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SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 11 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
CONTENT
This instruction outlines the process descriptions of NGL trains. There are three (3) NGL trains,
which are identical. The description is mentioned based on train number 1. All instrument tag
numbers on this section is prefixed “41-“ for Train 1 and “42-“ and “43-“ for Train 2 and 3 unless
otherwise noted.
The text includes:
1. INTRODUCTION
2. DESIGN BASIS
3. PROCESS DESCRIPTION AND CONTROL
4. OVERALL PLANT CONTROL
5. PROCESS CONTROL
6. COMPLEX CONTROL
7. REGENERATION /ABSORPTION LOGIC SEQUENCE DESCRIPTION
8. PROCESS THEORY
9. PROCESS VARIABLE
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SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 22 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
1 INTRODUCTION
The NGL Recovery Trains recover ethane and heavier hydrocarbons. The ethane recovery
is limited only by the minimum gross heating value specification on the residue gas of 930
BTU/SCF. The carbon dioxide content of the ethane plus NGL is specified as less than 1500
ppmv.
The NGL recovery unit consists of three identical trains; each designed to handle 33.3% of
the peak total inlet gas flow rate. The capacity of each train is 1333 MMSCFD.
Although the Haradh and Hawiyah inlet gas streams to each NGL recovery unit have been
dew-point controlled, it contains impurities such as nitrogen, carbon dioxide, mercury and
water, which adversely affect cryogenic processing to recover ethane and heavier
hydrocarbons (ethane plus).
The Haradh and Hawiyah inlet gas streams to each NGL recovery unit will be mixed inside
the train and then pre-cooled before passing through the molecular sieve beds for
dehydration and the activated carbon beds for mercury removal. The water is removed
using a molecular sieve dehydration system, since cryogenic temperatures are required to
recover ethane product and water freezing and hydrate formation shall be prevented. Since
brazed aluminum heat exchangers (BAHE) are used in the cryogenic process; mercury that
could attack the aluminum material removed in the activated carbon beds.
The ethane and heavier hydrocarbons are extracted from the methane component of the inlet
gas by fractionation in a demethanizer column. This is accomplished by liquefying the gas
streams using heat exchangers, turbo expanders, or Joule-Thompson (JT) valves before it
enters the demethanizer column. The demethanizer column operates at a controlled
pressure with heat being added to the bottom by means of reboilers and overhead
temperature being controlled by the cold feed stream. The overhead residue gas stream is
essentially ethane free and passes to the sales gas compression unit (B68) after
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SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 33 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
recompression by brake compressors.
The nitrogen is not removed from the inlet gas and simply passes through the plant with the
residue gas unaffected by the process.
The NGL products coming off the bottom of the demethanizer are primarily ethane, heavier
hydrocarbon liquids. Major part of carbon dioxide (CO2) in Haradh gas is removed in B65,
and remaining CO2 in Haradh gas and CO2 containing in Hawiyah gas pass through the
process with the ethane plus product and is send to NGL surge spheres (B67) as part of the
ethane plus liquid.
A simplified block diagram of the NGL trains is shown on the next page and Attachment 10.
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SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 44 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
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SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 55 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
The following is a brief description of the main facilities included in each NGL Train:
• Precondition System
Two Feed Gas enters this system, one from HUG-1 and the other from HDUG-1. The Dry
Hawiyah Feed Gas is coming from HUG-1 after filtration in B64. The Hawiyah gas inlet
does not have to be treated as the Carbon dioxide (CO2) was removed at the existing
Hawiyah Gas Plant. The Hawiyah gas goes through two heat exchangers which will lower
its temperature from 139 °F to 80 °F.
The Haradh Gas is wet gas because it is coming from DGA gas treating facility (B65) after
removing CO2. The wet Haradh gas enters a heat exchanger and a separator where the
temperature is reduced to 80 °F and the condensed liquid separated. Both Gas will then join
in a Static Mixer and fed to the Dehydration System.
• Molecular Sieve Gas Dehydration
The Feed Gas Dehydration Beds contain the molecular sieve used to dehydrate the feed gas.
There are 6 beds per train, 5 beds are on absorption and one is on regeneration/stand-by at
any time.
• Mercury Removal
The Mercury Removal Beds use activated carbon to remove the mercury from the feed gas.
The carbon beds are disposable, and when fully loaded with mercury, must be replaced with
fresh material.
The dehydrated mercury free gas flows to the dust filters where it is filtered to remove any
entrained fine dust and particles.
• Regeneration Gas System
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SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 66 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Sales gas heated to 550 °F is used to regenerate the beds. The regeneration gas is heated in
two Heaters. The first heater utilizes medium pressure hot water to heat the regeneration
gas to 400 °F. The second heater utilizes electricity to further heat the regeneration gas to
550 °F.
• Cryogenic System
The gas is cooled through the Brazed Aluminum Heater Exchanger to approximately -55 °F,
and separated liquids are routed to the Demethanizer.
Gas from the expander feed separator is split into two streams. One stream (28 %vol) is fed
to the Demethanizer Overhead Exchanger where it is cooled and passes through an
expansion valve where the pressure is dropped to 259 psig. This stream is then fed to the top
separator section of the Demethanizer.
The remaining gas (72 %vol) from the expander separator is fed to the turbo expanders. The
gas exits the turbo expanders at approximately 260 psig and -124 °F and is fed to the top tray
of the Demethanizer.
Power recovered from the expanders is utilized in the brake compressor portion to increase
the pressure of the residue gas. There are two 50% capacity Turbo-Expanders in each NGL
train.
The Demethanizer distills the liquefied NGLs to produce an ethane rich NGL product that
meets the required specifications.
It is required to have a CO2 content of less than 1500 ppmv, and no more than 2.5% methane
in ethane. (The NGL liquid produced as bottoms product is pumped to the surge spheres).
• Demethanizer
The Demethanizer overhead gas stream (Residue Gas) flows through a series of Brazed
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SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 77 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Aluminum Heat Exchanger and is routed to the suction of the Brake Compressors where
those are compressed and sent to the Sales Gas Compression trains (Plant B68).
There are three reboilers on the Demethanizer, two side reboilers and a bottom reboiler with
auxiliary reboiler.
• Propane Refrigeration
Propane Refrigeration is used to assist in cooling the feed gas stream. Each NGL train has a
dedicated system and consists of two-motor driven, two-stage centrifugal compressors.
2 DESIGN BASIS
The NGL recovery unit consists of three identical trains that include the following main
facilities. The description is mentioned based on train number 1. All instrument tag
numbers on this section is prefixed “41-“ for Train 1 and “42-“ and “43-“ for Train 2 and 3
unless otherwise noted.
2.1 SYSTEM CAPACITY
The NGL recovery unit consists of three identical trains; each designed to handle 33.3% of
the peak total inlet gas flow rate. The capacity of each train is 1,323 MMSCFD. Turndown
capability is a minimum of 50% of design capacity.
The HNRP will recover from the inlet gases approximately 310,000 BPD of C2+ NGL
(180,000 – 185,000 BPD), whose ethane content is 60 mol%.
Each NGL train consists of the follows:
• six 20% capacity molecular sieve beds per train – 5 beds are on adsorption and one
is on regeneration at any point in time.
• five 20% capacity activated carbon beds for mercury removable system
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SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 88 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
• two 50% capacity turbo expander / brake compressors (50% x 2, no spare)
• one demethanizer column with reboilers
• two 50% capacity two-stage refrigerant compressors (no spare)
• Pre-coolers and Brazed aluminum heat exchangers, etc.
2.2 FEED AND PRODUCT DATA
The ethane recovery is limited only by the minimum gross heating value specification on the
residue gas of 930 BTU/SCF. The CO2 content of the C2+ NGL is specified as less than
1500 ppmv.
The design parameters of the NGL unit are as follows:
• Capacity of each train: 1,323 MMSCFD
• Turndown capability: to a minimum of 50% of design capacity
1) Feed Gas Pre-cooling
• Dry inlet gas temperature of Hawiyah gas stream: 140 ºF
• Wet inlet gas temperature of Haradh gas downstream of gas treating: 146 ºF
(water saturated)
• Pre-cooling temperature for dehydration: 80 ºF
2) Molecular Sieve Gas Dehydration
• Design water content of the wet gas for molecular sieve: 20 lb/MMSCF at
1,323 MMSCFD and saturated at 680 MMSCFD (Haradh gas only case)
• Water content of the dehydrated gas: less than 0.1 ppmv.
• Designed bed life is 3 years
• Regeneration gas temperature: 550 ºF (heating) and 90 ºF (cooling)
• Regeneration gas flow rate: Maximum 60 MMSCFD
3) Mercury Removal
• Design mercury content of the inlet gas: 70 micrograms/ Nm3
• Mercury content of the dehydrated gas: less than 0.01 microgram/Nm3 of
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03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 99 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
gas.
• Designed bed life is 3 years
4) C2+ NGL recovery
• Heat content of residue gas 930 BTU/SCF (minimum gross heating value)
• NGL liquid produced as a bottoms product when processed at Saudi
Aramco’s NGL Fractionation plants to meet the following ethane
specifications:
- CO2 content of less than 1500 ppmv
- No more than 2.5% mole methane in ethane.
5) Propane Refrigeration
• Refrigeration design levels:
(1) 1st suction: -14 ºF at 13 psig
(2) side stream: economizer 52 ºF at 83 psig, chillers 55 ºF at 83 psig and 75
ºF at 118 psig
(3) condenser 140 ºF at 302 psig
• The heat gain in the propane refrigeration system is 2% of the chiller duties in
summer operation and 1% of the chiller duties in winter operation.
3 PROCESS DESCRIPTION AND CONTROL
The following description is based on train 1 (Unit 41), but is also applicable to train 2 & 3
(Unit 42 & 43).
3.1 FEED GAS PRE-COOLING
The pre-cooling area equipment is used to lower the temperature of the feed gas stream to
80 °F, which is based on hydrate formation temperature of approximately 62 °F plus 18 °F
margin, before it passes into the Molecular Sieve Dehydrators. The feed gas streams are
Hawiyah gas and Haradh gas. Haradh gas is coming from gas tearing trains (B65) and water
saturated, although Hawiyah gas is dry.
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SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 1100 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
The Feed Gas/Residue Gas Exchanger (B66-E-0101 A/B) is the first set of shell-and-tube
type heat exchangers on Hawiyah feed gas lines in the NGL recovery process. It is used to
cool the Hawiyah inlet gas to 90 °F. Due to the presence of mercury in the gas, this
exchanger is a shell-and-tube type heat exchanger of steel material.
After the Feed Gas/Residue Gas Exchanger, the Hawiyah gas is fed to the Hawiyah Gas
Chiller (B66-E-0102). It is a steel tube bundle inside a propane-bath kettle-type heat
exchanger and is used to cool the gas to 80 °F. The propane refrigerant for this chiller is fed
from the propane sub-cooler (B66-E-0117 A/B). The outlet gas from this chiller is fed to the
static mixer where it is mixed with the chilled Haradh gas.
The Haradh Gas Chiller (B66-E-0108) is a steel tube bundle inside a propane-bath
kettle-type heat exchanger and is used to cool the wet Haradh gas from 146 °F to 80°F and
condense the majority of the water vapor. The propane refrigerant for this chiller is fed from
the propane sub-cooler (B66-E-0117 A/B).
Gas from the Haradh Gas Chiller is fed to Haradh Gas Chiller Separator (B66-D-0101)
to remove the water/entrained DGA condensed in the Haradh Gas Chiller. The
condensed is recycled back to the gas treating trains (B65) where the water/entrained
DGA is reused by adding it to the Diglycolamine (DGA) solution to minimize DGA
loss.
The chilled Hawiyah gas and the chilled Haradh gas are commingled and mixed in the static
mixer (B66-SM-001). The purpose of this mixer is to ensure the mixture is homogeneous
and is without stratification, which could cause unequal loadings of water in the molecular
sieve dehydration beds.
If temperature of Hawiyah gas is lower than that of Haradh gas, Condensation of water may
take place and, thereby, performance of molecular sieves dehydrator worsens. Therefore,
the differential temperature between Hawiyah and Haradh gas at mixer inlet is monitored
and the alarm signal is initiated when warmer Haradh gas (i.e. lower Hawiyah gas) is
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SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 1111 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
detected.
3.2 MOLECULAR SIEVE GAS DEHYDRATION
The Feed Gas Dehydration Beds (B66-D-0102A/B/C/D/E/F) contain the molecular sieve
used to dehydrate the feed gas to 0.1 ppmv (0.1 ppmV water content corresponds to less than
-174degF at 263psig which is the operating condition of demethanizer reflux line). This low
water content is required to prevent hydrate formation in the cryogenic section of the plant.
There are 6 beds per train – 5 beds are on adsorption and one is on regeneration or stand-by
at any point in time. Each bed is sized to process 20% of the inlet gas flow. Adsorption is
done with the gas flowing vertically down through the bed. Regeneration gas is lean sales
gas and taken from the discharge of each sales gas compressors (B68) and flowing vertically
up through bed.
Once a bed has adsorbed as much water as the molecular sieve can handle, it is placed on
regeneration. Sales gas heated to 550 °F is used to regenerate the beds. Following
regeneration, the bed is cooled down to 90 °F, which is the normal operating temperature
plus 10 °F, using cooled lean sales gas.
Sequencing of the dehydration bed switching valves is to be controlled by timer sequencers
programmed into the DCS control system.
The water content of the dehydrator outlet gas will be monitored with an on-line moisture
analyzer. The time span the beds are on adsorption shall be adjusted to ensure that the beds
are on adsorption as long as possible while ensuring that water break-through does not
occur.
The outlet gas from the Feed Gas Dehydration Beds is fed to the Mercury Removal Beds.
During the regeneration heating cycle, the sales gas is heated in two regeneration gas heaters.
The first of the heaters, the Regen Gas Hot Water Heater (B66-E-0103A/B), utilizes
medium pressure hot water to heat the regeneration gas to 400 °F. The second heater, the
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SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 1122 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Regen Gas Electric Heater (B66-E-0105 A/B), utilizes electricity to further heat the
regeneration gas to 550 °F.
The regeneration gas can be automatically heated in two steps by activating or deactivating
the electric heater and by controlling the hot-water flow rate.
During the regeneration cooling cycle, the Regen Gas Cooling Cycle Chiller (B66-E-0104)
cools the sales gas to 90 °F using propane refrigerant.
Two coolers in series cool the regeneration gas from the gas dehydration beds. The first
cooler is the Regen Gas Air Cooler (B66-E-0106), a fin-fan cooler that cools the gas to
approximately 145 °F. The second cooler, the Regen Gas/Propane Chiller (B66-E-0107),
cools the gas to 80 °F using propane refrigerant. This is to condense as much water vapor as
practicable. Hydrate formation temperature is approximately 51 °F. The gas is then routed
to the Regen Gas Separator.
The Regen Gas Separator (HP) (B66-D-0105) separates any water that condenses out of the
regeneration gas stream as it is cooled. The gas from B66-D-0105 is then routed to sales gas
pipeline via the regeneration gas blowers KO drums and Blowers (B64). The water from
B66-D-0105 is flashed to the Regen Gas LP Knock Out Drum (B66-D-0106) to
depressurize it to 5 psig. Condensed water is routed to the Oily Water Sewer (OWS) and the
flashed gas is routed to LP flare.
3.3 MERCURY REMOVAL
The gas from the Dehydration Beds passes through the Activated Carbon Beds
(B66-D-0107A/B/C/D/E). Flow direction is vertically down through the beds. The beds
contain an activated carbon that removes the mercury from the feed gas. The activated
carbon is disposable, and when fully loaded with mercury, the bed must be replaced with
fresh material.
There are five beds for each NGL train. Each is sized for 20% of the inlet-gas flow.
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SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 1133 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
The Carbon Bed Outlet Dust Filters/Basket Strainers (B66-D-0103A/B/C/D/E and
B66-D-0104 A/B/C/D/E) are used to remove the fine dust and particles to prevent foiling or
plugging of the downstream brazed aluminum heat exchangers. Each dust filter/basket
strainer is dedicated to one of the activated-carbon beds.
3.4 C2+ NGL RECOVERY
The NGL Recovery Area equipment is used to lower the temperature of the gas stream to
liquefy and distill the NGLs.
The Feed Gas Exchanger (B66-E-0110 A/B) receives gas from the molecular-sieve
dehydration unit. The gas is fully dehydrated and is free of mercury. The exchanger is a
brazed aluminum heat exchanger (BAHE) and has three sections (passes) – the feed gas
section (Pass A), a residue gas section (Pass B), and the Demethanizer reboiler section (Pass
C). It is used to cool the feed gas to approximately 30 ºF.
Two 50% units (A &B) have been provided to allow one unit to be taken out of service for
maintenance (back puffing) without shutting down the entire train.
Following this exchanger, the gas is split into two streams, approximately 42% being fed to
the Second Stage Feed Gas Chiller (B66-E-0114), and the remaining 58% being fed to the
Warm Gas Exchanger (B66-E-0111).
The Second Stage Feed Gas Chiller (B66-E-0114) is a BAHE (core) inside a propane-bath
kettle-type heat exchanger and is used to cool the gas to approximately -9 ºF. The propane
refrigerant for this chiller is fed from the Refrigerant Economizer (B66-D-0115).
The Warm Gas Exchanger (B66-E-0111) receives gas from the Feed Gas Exchanger. The
exchanger is a brazed aluminum heat exchanger (BAHE) and has three sections (passes) –
the feed gas section (Pass A), a residue gas section (Pass B), and the Demethanizer bottom
side reboiler section (Pass C). It is used to cool the inlet gas to approximately -9 ºF.
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SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 1144 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
The feed gas fluid stream from the Warm Gas Exchanger is commingled with the feed gas
fluid stream from the Second Stage Feed Gas Chiller and is routed to the Chiller Separator.
The Chiller Separator (B66-D-0110) receives a two-phase fluid stream from the Second
Stage Feed Gas Chiller and from the Warm Gas Exchanger. The separator is designed with
a single inlet, a single liquid outlet and two vapor outlet connections, one vapor outlet at
each end of the vessel. Each of these vapor outlet connections is provided with a mist
eliminator pad. Liquids separated are routed to the Demethanizer as a side feed. The
remaining gases are fed to the Cold Gas Exchanger.
The Cold Gas Exchanger (B66-E-0112) receives feed gas from the Chiller Separator. The
exchanger is a brazed aluminum heat exchanger (BAHE) and has three sections (passes) –
the feed gas section (Pass A), a residue gas section (Pass B), and the Demethanizer top side
reboiler section (Pass C). It is used to cool the inlet gas to approximately -56 ºF.
The Expander Feed Separator (B66-D-0111) receives a two-phase stream from the Cold Gas
Exchanger. The separator is designed with a single inlet, a single liquid outlet and two
vapor outlet connections, one vapor outlet at each end of the vessel. Each of these vapor
outlet connections is provided with a mist eliminator pad. Liquids separated are routed to
the Demethanizer as a side feed.
Following this separator, the gas is split into two streams, approximately 28% being fed to
the Demethanizer Overhead Exchanger (B66-E-0113), and the remaining 72% being fed to
the Turbo-Expanders.
The Demethanizer Overhead Exchanger (B66-E-0113) receives feed gas from the Expander
Feed Separator. The exchanger is a brazed aluminum heat exchanger (BAHE) and has two
sections (passes) – the feed gas section (Pass A), and a residue gas section (Pass B). It is
used to cool the feed gas to approximately -159 ºF.
The liquid stream exiting the exchanger is passed through a Joule-Thompson (J-T)
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_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 1155 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
expansion valve where the pressure is dropped to 264 psig and the temperature is decreased
to -174 ºF. The fluid is then fed to the top packed section of the Demethanizer.
The Turbo-Expander/Brake Compressor Units (B66-K-0110A/B) receive gas from the
Expander Feed Separator. The two-phase fluid stream exits each of the expanders at
approximately 276 psig and -123 ºF, and are fed individually to the top tray of the
Demethanizer. Power recovered in the expander portion of the Turbo-Expander is utilized
in the compressor portion to increase the pressure of the residue gas.
There are two 50% capacity Turbo-Expanders in each NGL train; there are no spare or
stand-by units. The Turbo-Expander/Brake Compressor units are connected in parallel.
The Demethanizer (B66-C-0110) is used to distill the recovered liquid NGLs and produce
an ethane rich NGL product, which meets the methane and carbon dioxide content
specifications. The Demethanizer receives a two- phase (gas and liquid) feed from the
Demethanizer Overhead Exchanger and from the two Turbo-Expanders. It also receives
flashed liquid NGLs from the Expander Feed Separator and from the Chiller Separator.
The demethanizer smaller diameter section has 34 Flexitrays (Valve trays) with four
chimney trays and larger diameter section has random packing with two chimney trays.
There are three reboilers on the Demethanizer. The bottom reboiler is heated by the Feed
Gas Exchanger, the bottom side reboiler is heated by the Warm Gas Exchanger, and the top
side reboiler is heated by the Cold Gas Exchanger.
The NGL liquid produced as a bottoms product shall meet the ethane product specification
when further processed at Saudi Aramco’s NGL Fractionation plants.
A Demethanizer Auxiliary Reboiler (B66-E-0118) is provided for one JT / one
Turbo-Expander operation mode so that the produced NGL liquids meet the required
specifications.
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_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 1166 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
3.5 PROPANE REFRIGERATION
Propane Refrigeration is used to supply the cold source for heat removal. The Propane
Refrigeration system in each NGL train has two 50% (Unit A & Unit B) capacity
compressors, suction drums, condensers and accumulators. The sub-cooler and economizer
are common to both Unit A and Unit B.
The Propane Refrigerant Compressors (B66-K-0111A/B) are centrifugal compressors and
have two stages. The low pressure stage takes propane vapors from the Second Stage Feed
Gas Chiller (B66-E-0114) and the high pressure stage takes propane vapors from the
Refrigerant Economizer (B66-D-0115), Hawiyah Gas Chiller (B66-E-0102), Regen Gas
Cooling Cycle Chiller (B66-E-0104), Regen Gas/Propane Chiller (B66-E-0107), and
Haradh Gas Chiller (B66-E-0108).
The discharge from the compressors is routed to the Refrigerant Condensers (B66-E-0115
A/B).
The Refrigerant Compressors are equipped with anti-surge flow-control loops on the first
and second stages. Each recycle-gas stream is temperature controlled by quenching (i.e.,
mixing) with liquid refrigerant.
The Refrigerant First Stage Compressor Suction Drums (B66-D-0112A/B) and the
Refrigerant Second Stage Compressor Suction Drums (B66-D-0113A/B) are intended to
prevent any liquid propane from entering the suction of the compressors. Each of the drums
is equipped with a mist eliminator pad and heating coil in the bottom of the drum used to
vaporize any liquid propane which accumulates in the drum. The coils are heated using hot
refrigerant compressor discharge gas.
Each compressor discharges into a Refrigerant Condenser (B66-E-0115A/B). This is a
battery of air cooled heat exchangers. Condensed propane refrigerant from the condenser is
combined and fed to the Refrigerant / Water Sub-cooler (B66-E-0117 A/B).
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_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 1177 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
A Refrigerant Accumulator (B66-D-0114A/B) is installed between the Refrigerant
Condenser and the common sub-cooler. System liquid fluctuations will be accommodated
in the accumulator. In order to ensure there is always sufficient pressure in the accumulator
to allow flow through the chillers, a hot gas by-pass is installed around the Refrigerant
Condenser. This maintains pressure in the Refrigerant Accumulator when ambient
temperatures decrease.
A Refrigerant / Water Sub-cooler (B66-E-0117 A/B) is installed downstream of the
Refrigerant Accumulators. The Refrigerant / Water Sub-cooler uses chilled cooling water
that has been further cooled by the export NGL in the Product Surge area (B67).
The compressors are equipped with a common Refrigerant Economizer (B66-D-0115) to
reduce the overall load on the compressors.
Propane refrigerant transferred from the storage facility in Plant B67 to Plant B66 is filtered
through a Refrigerant Filter (B66-D-0116) before being distributed into the refrigerant
circuit. During a unit shutdown, propane refrigerant is transferred from Plant B66 to B67 via
the Refrigerant Return Pump (B66-G-0114) from economizer and accumulators.
During Haradh gas only operation, refrigerant compressors' side stream duty is almost same
as that of normal operation, however, 1st suction stream duty is reduced to less than 45% of
normal and possible minimum flow recycle is required for 1st stage only. To prevent
minimum flow recycle and save energy consumption, side stream flow is bypassed to 1st
suction via letdown valve.
4 OVERALL PLANT CONTROL
On the main gas line, there are five control valves for overall plant control as below:
1. Hawiyah Feed Gas Line, 41/42/43-FV-001
2. Haradh Feed Gas Line, 31/32-FV-003
3. 41/42/43-HV-311/330 (Expander inlet guide vane) and FV-238 (DeC1 reflux)
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_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 1188 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
4. 41/42/43-PV-537 (DeC1 overhead)
5. 61/62/63/64-FV-001, Sales Gas Compressor Inlet
The detail of control is mentioned the following section and B74-J-BE530023
(S-741-1371-101), Specification for Complex Control Strategies, para 6.
4.1 PURPOSE
The priority of purpose is the follows.
a. To maintain inlet pressure to turbo expander (K-0110A/B, K-0210A/B,
K-0310A/B).
b. To maintain constant pressure in both inlet pipelines (to match the plant
processing rate to the supply from both pipelines).
c. To provide flexibility of evenly splitting both Hawiyah and Haradh gas flows
between all three NGL recovery trains.
d. To limit gas flow through each NGL train to the train design capacity and to
allow any single train capacity testing during multi-train operation, also to
limit Hawiyah gas flow through a single line train.
e. To automatically perform all the above independently of number DGA, NGL
and sales compression trains in operation.
f. To ensure priority of operation with Haradh gas, over Hawiyah gas, in case of
reduced plant capacity.
g. To perform all the above with minimum pressure drop to the gas flow.
Demethanizer overhead pressure is controlled by 4x-PV-537 during normal operation.
During JT operation, Demethanizer overhead pressure is depend on sales gas
compressor master pressure control and pipeline pressure.
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_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 1199 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
4.2 STRADDLE CONTROL (PLANT BYPASS): (GTCC PORTION.)
This control loop operates the plant bypass on the Haradh & Hawiyah sales gas lines. In the
event of a plant trip or emergency, gas feed is bypassed around the Hawiyah NGL plant.
This loop is controlled by continually monitoring the Pressure in the HUG-1 and HDUG-1
pipelines In and Out of the plant.
If the Hawiyah gas supply header pressure exceeds its preset value, Hawiyah Gas supply
header high pressure protection controller 21-PIC-005 opens pipeline bypass valves,
21-PV-005A/B to reduce the header pressure.
Differential Pressure 21-PDI-007 will provide permissive-to-open bypass valves,
21-PV-005A/B via DCS logic. If the pressure difference between supply header pressure
and return pressure becomes less than preset value, this DCS logic will close the pipeline
bypass valves to avoid reverse flow. A 48 inches check valve is also available to
mechanically ensure that no back flow will occur.
If the Haradh gas supply header pressure exceeds its preset value, Haradh Gas supply header
high pressure protection controller 22-PIC-105 opens pipeline bypass valves,
22-PV-105A/B to reduce the header pressure.
Differential Pressure 22-PDI-008 will provide permissive-to-open bypass valves,
22-PV-105A/B via DCS logic. If the pressure difference between supply header pressure
and return pressure becomes less than preset value, this DCS logic will close the pipeline
bypass valves to avoid reverse flow. A 48 inches check valve is also available to
mechanically ensure that no back flow will occur.
4.3 HAWIYAH GAS AND HARADH GAS FLOWRATE CONTROL
Nitrogen component of Hawiyah feed gas is higher than that of Haradh feed gas. If
Hawiyah gas is only feed to DeC1, Nitrogen content of sales gas is increased and possible
off-spec sales gas occurs. In view of keep the heating value of sales gas as minimum 930
MMBTU/SCF, Hawiyah gas is to be reduced first in case of reduced plant capacity.
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_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 2200 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
For C2 recovery rate, the difference between the Hawiyah gas maximum case and Haradh
gas maximum case is +/- 0.3% and negligible.
Therefore, ratio control for Haradh gas and Hawiyah gas flow rate is not required and
Haradh feed gas flow to each NGL train is controlled by balance of NGL train Maximum
total flow controller (41/42/43-FIC-237) and Hawiyah gas flow controller
(41/42/43-FIC-001).
Haradh gas and Total NGL feed gas flow ratio of each NGL train is calculated
(41/42/43-FY-009) and indicated in DCS (41/42/43-FI-009) as a reference for operator.
4.3.1 Maximum Flow Limit Control on Total Hawiyah and Total Haradh Feed Lines
The maximum total feed gas flow from Hawiyah can be set through 40-HIC-004. When
measured total gas feed flow from Hawiyah gas pipeline exceeds this limit, 40-HIC-004 will
override signal from 21-PIC-006 via low signal selector, 40-PY-036 and thus limit the
setpoint of 40-FIC-002.
The maximum total feed gas from Hawiyah and Haradh to NGL train is limited by
41/42/43-FIC-237. 41/42/43-FIC-237 setpoint is about 1,400 MMSCFD in consideration of
the Demethanizer, B66-C-0*10 capacity. When this value is exceeded, 41/42/43-FIC-237
will manipulate the expander Inlet guide vane to close via low signal selector,
41/42/43-PY-499A and override signals from 41/42/43-PIC-499A.
The maximum total Haradh feed gas to DGA units is around 1,700 MMSCFD in
consideration of the DGA unit capacity of 816 MMSCFD per DGA unit. This maximum
limit can be set through 22-HIC-004. When this limit is exceeded, 22-HIC-004 will override
signal from 22-PIC-004 via low signal selector, 22-PY-004 and thus limit the setpoint of
22-FIC-003.
When one or two NGL trains are shutdown, the total Haradh gas max total flow limit will be
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_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 2211 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
calculated by 40-FY-004. When 41/42/43-FIC-004 process value read lower than a preset
value, 40-FY-004 will consider that train to be blocked/shutdown and reduce 22-FIC-003
setpoint via low signal selector 22-PY-004 and override signal from 22-PIC-004 and
22-HIC-004.
No. of Running Trains Max. Total Haradh Gas Feed Flow Rate
0 or 1 900 MMSCFD
2 or 3 1700 MMSCFD
The set point of maximum feed gas rate of total feed gas (Hawiyah and Haradh) and Haradh
gas is calculated from the number of operating trains as below:
NGL train # Hawiyah + Haradh Gas output Haradh Gas (10-FY-004)
1 1,400 MMSCFD 900 MMSCFD
2 2,800 MMSCFD 1,700 MMSCFD
3 4,380 MMSCFD 1,700 MMSCFD
Logic for 40-FY-004 output is as follows:
Three NGL Trains in operation
If 41-FIC-004.PV >= X and 42-FIC-004.PV >= X and 43-FIC-004.PV >= X
Then 40-FY-004.MV= 1700
Two NGL Trains in operation
If 41-FIC-004.PV < X and 42-FIC-004.PV >= X and 43-FIC-004.PV >= X or
If 41-FIC-004.PV >= X and 42FIC004.PV< X and 43-FIC-004.PV>=X or
If 41-FIC-004.PV >= X and 42-FIC-004.PV >= X and 43-FIC-004.PV < X
_____
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_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 2222 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Then 40-FY-004.MV= 1700 (MMSCFD)
One NGL Train in operation
If 41-FIC-004.PV < X and 42-FIC-004.PV<X and 43-FIC-004.PV>= X or
If 41-FIC-004.PV < X and 42-FIC-004.PV>= X and 43-FIC-004.PV<X or
If 41-FIC-004.PV >= X and 42-FIC-004.PV< and 43-FIC-004.PV<X
Then 40-FY-004.MV= 900 (MMSCFD)
Where “X” is low flow value to consider that the train is blocked or shutdown.
The DCS logic shall be provided to set the Max Total Haradh Gas Feed Flow Rate to
22-HIC-004 as one shot action in case of the number of running NGL train becomes less
than 2.
A rate of change limiter in “SCFD/ sec” shall be provided for 22-HIC-004 output signal to
change gradually when number of NGL trains running is changed.
4.3.2 Equal Distribution of Total Haradh Flow on NGL Trains
NGL trains are to have same flow rate for all 3 Hawiyah feed flow to NGL trains, and all 3
Haradh feed also at the same flow rate which is mixed with Hawiyah feed gas on each Train.
The ratio of Hawiyah to Haradh gas feed is not really a main concern but an unevenly
distributed Hawiyah & Haradh feed flows may shorten the running time of Dehydration
system on NGL Trains, and may cause operation problem.
At normal operation, where 3 NGL trains are operating, to avoid overloading the
dehydration systems by uneven distribution of Haradh feed, Hawiyah ratio setter,
41/42/43-FY-001B will be automatically adjusted by 41/42/43-FDC-010 to maintain a set
value on Haradh flow to each NGL train. Process value of 41/42/43-FIC-004.PV will be
averaged, 40-FY-003 and the calculated value will then be compared to individual NGL
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_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 2233 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
train process value, 41/42/43FIC004.PV. The difference between process value and average
value (41/42/43-FIC-004.PV-Average) will then be used to automatically adjust the ratio set
via 41/42/43-FY-001B on corresponding Hawiyah flow.
DCS logic will disable this control by changing the mode of 41/42/43-FY-001B Ratio Setter
from “CAS” to “AUTO” when one of NGL trains is shutdown and keep the last ratio
setpoint.
4.3.3 Hawiyah Gas Feed Flow Control & Supply Header Pressure Control
During normal plant operation, Hawiyah gas supply header pressure controller, 21-PIC-006
will control the header pressure by manipulating the setpoint of total Hawiyah feed gas flow
controller, 40-FIC-002 via low signal selector, 40-PY-036. The total Hawiyah feed gas
flowrate is then equally distributed by controller, 40-FIC-002 by manipulating the setpoint
of 41/42/43-FIC-001 for each NGL train via ratio setter, 41/42/43-FY-001B. Hawiyah feed
gas flow to each NGL train is controlled by 41/42/43-FIC-001 that manipulates control
valve, 41/42/43-FV-001. The total Hawiyah gas feed flow rate is calculated from the PV
value of 41/42/43-FIC-001 and used as process value of total Hawiyah gas feed flow rate
controller 40-FIC-002.
If operator would like to limit the maximum total flow rate through the NGL trains, operator
can set the maximum flow limit to the 40-HIC-004 connected with the total Hawiyah gas
feed flowrate setpoint via low signal selector, 40-PY-036.
21-PIC-006 to be “non-linear gain PI controller” will minimize the change of feed flow to
NGL unit under small Hawiyah Gas header pressure changes. The non-linear gain PI
controller will lower the proportional gain to moderate the 41/42/43-FV-001 movement
when the pressure variation is within a range (Gap). This Gap will be decided at later and
can be modified during plant commissioning.
The total gas flowrate, Hawiyah and Haradh gas to NGL train is limited by total feed gas
max flow limit controller (DCS) described in section 4.2.
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_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 2244 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
If the operator would like to operate one or two NGL trains in FIC (Stable feed flow) mode
and the remaining trains by PIC - FIC cascade control, the DCS operator can disconnect the
cascade connection of each train to be run in FIC mode by changing Hawiyah gas
41/42/43-FIC-001 on each NGL train to Auto mode.
If the expander suction pressure exceeds the preset value, the High Pressure protection
controller, 41/42/43-PIC-499B will reduce feed gas flow rate from Hawiyah gas header via
41/42/43-HIC-014 and low signal selector, 41/42/43-FY-001. Even if the gas feed from
Hawiyah pipeline is reduced but the expander suction pressure still exceeds its preset value,
41/42/43-PIC-499B will then reduce feed gas from Haradh gas supply header.
If the Hawiyah gas supply header pressure exceeds its preset value, Hawiyah gas supply
header high pressure protection controller 21-PIC-005 opens pipeline bypass valves to
reduce the header pressure via low signal selector.
4.3.4 Haradh Gas Feed Flow Control & Supply Header Pressure Control
During normal plant operation, Haradh gas supply header pressure controller 22-PIC-004
will control the header pressure by manipulating the setpoint of the total Haradh gas feed
flow controller, 22-FIC-003 via low signal selector, 22-PY-004. The total Haradh feed gas
is then equally distributed to two DGA trains by controller, 22-FIC-003 by manipulating the
setpoint of controller, 3*-FIC-003 to each DGA via ratio setter, 3*-FY-036/039. Haradh
feed gas flow to each DGA train is controlled by 3*-FIC-003 that manipulates control valve,
3*-FV-003. The total Haradh gas feed flow rate is calculated from the PV value of
3*-FIC-003 and used as process value of total Haradh gas feed flow rate controller
22-FIC-003.
If operator would like to limit the maximum total flow rate through the DGA trains, operator
can set the maximum flow limit to the 22-HIC-004 connected with the total Haradh gas feed
flowrate setpoint via low signal selector, 22-PY-004.
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_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 2255 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
22-PIC-004 to be “non-linear gain PI controller” will minimize the change of feed flow to
DGA units under small Haradh Gas header pressure changing. The non-linear gain PI
controller will lower the proportional gain to moderate the 3*-FV-003 movement when the
pressure variation is within a range (Gap). This Gap will be decided at later and can be
modified during plant commissioning.
The total Haradh gas max flow rate to NGL trains via DGA trains is limited by total Haradh
gas max flow limit controller (DCS) described in section 4.3.1.
If operator would like to operate one DGA train in FIC (Auto mode) and other train by PIC
- FIC cascade control, DCS operator can disconnect the cascade connection by changing the
mode of Haradh gas 3*-FIC-003 on DGA train to Auto mode which the operator would like
to operate the train in FIC mode, i.e. stable feed flow rate.
If the expander suction pressure exceeds the preset value, the expander suction header high
pressure protection 41/42/43-PIC-499B will reduce feed gas flow rate from Hawiyah gas
header first, and if the header pressure is still higher than the preset value, the
41/42/43-PIC-499B will reduce the gas flow rate from Haradh gas pipeline via
3*-HIC-AAA and low signal selector, 3*-FY-003.
If the Haradh gas supply header pressure exceeds its preset value, the High Pressure
protection controller 22-PIC-105 opens pipeline bypass valves to reduce the header pressure
via low signal selector. Refer to Section 4.2.
4.4 EXPANDER INLET HEADER PRESSURE CONTROL AND NGL TRAIN
MAXIMUM TOTAL GAS FLOW LIMIT
At normal operation, the turbo expander inlet header pressure is controlled at a pseudo
setpoint value via 41/42/43-PIC-499A. 41/42/43-PIC-499A output goes through low signal
selector, 41/42/43-PY-499A to manipulate the 2 set of Turbo Expanders’ IGVs
(41/42/43-HV-311, 330) or Expander bypass JT valves (41/42/43-FV-237A, C) via
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03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 2266 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
expander/compressor control system.
The Demethanizer overhead feed flow controller, 41/42/43-FIC-238 receives its setpoint
from total feed flow 41/42/43-FIC-237 via fixed flow ratio setter, 41/42/43-FY-238. By this
ratio setter, the Demethanizer overhead (OVHD) feed flow through the DeC1 OVHD
exchanger (B66-E-*13) via 41/42/43-FV-238 is maintained at a preset flow ratio of total gas
flow to the NGL train.
The 41/42/43-PIC-499A pseudo pressure set point value is calculated via
41/42/43-PY-499C which consider the following:
P499A setpoint = Higher Signal ((P499A (PFD Value) - PDEH), PFIC004.MV)
1. P499A (PFD Value) = 748 psig as per PFD
2. PDEH = a manual term to allow bias for aging desiccant higher pressure drop
If Pressure drop on dehydrators is increased, the operator have to compare PDEH with
other trains and determine a PDEH bias value (from zero to a certain value) in order to
have same operating pressure at mixing point of Hawiyah and Haradh Gas on three
NGL trains. Same pressure at mixing point of Hawiyah and Haradh Gas on three NGL
trains means that the gas flow from Haradh gas pipeline will be equalized.
3. PFIC004 = 41/42/43-FIC-004 output value in psig
If 41/42/43-FIC-004.PV exceed its set point (Maximum Haradh Gas flow limit per
train), 41/42/43-FIC-004 output value will be increased. If 41/42/43-PIC-499A.SP is
increased and 41/42/43-PIC-499A.PV is increased, the Haradh gas flowrate will be
decreased because the Haradh flowrate is determined by the pressure balance between
DGA outlet header pressure and mixing point pressure between Hawiyah and Haradh
gas.
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03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 2277 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Haradh gas distribution to each NGL trains is by hydraulic balancing by the piping and
resistance (dehydrator pressure drops). Hawiyah flow to each NGL train is controlled
by 41/42/43-FV-001. The Haradh gas must be balanced to avoid overloading the
dehydrators in the units (Max = 680 MMSCFD @ Haradh only case). The overall flow
distribution must be biased to prevent possible crushing the dehydrator beds as the
desiccant ages.
Total gas flow rate to Demethanizer (DeC1) is also limited by NGL train total flow
controller (41/42/43-FIC-237) via low signal selector, 41/42/43-PY-499A. When the
limit setpoint around 1,400 MMSCFD is exceeded, 41/42/43-FIC-237 will override
41/42/43-PIC-499A to manipulate the Turbo expander IGVs (41/42/43-HV-310,330).
This is to protect DeC1 from operating at over the design capacity.
If the sales gas (SG) compressor suction pressure exceeds its preset value due to one or
more of SG compressor trip, the SG suction header high pressure protection 90-PIC-016
via SG compressor master pressure validation controller will override the signals from
41/42/43-PIC-499A and 41/42/43-FIC-237 via low signal selector, 41/42/43-PY-499A.
In this case, 60-PIC-016 will manipulate the opening of the turbo expander IGVs to
reduce DeC1 overhead flow.
If the expander suction pressure exceeds the preset value, the Header High Pressure
protection, 41/42/43-PIC-499B will reduce feed gas flow rate from Hawiyah gas
pipeline first and if the header pressure is still higher than the preset value, the
41/42/43-PIC-499B will reduce the gas flow rate from Haradh gas pipeline (especially
for Haradh Gas Only Operation).
The control action of the SG suction Header High Pressure protection 60-PIC-016 and
expander suction header High Pressure protection 41/42/43-PIC-499B are reverse (the
output of the controller will decrease if suction pressure measurement increases) and the
expander suction header pressure controller 41/42/43-PIC-499A is direct (output of the
controller will increase if pressure measurement increases).
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03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 2288 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Operator can limit the NGL train total gas flow rate during start-up or during normal
operation by changing the controller 41/42/43-FIC-237 setpoint.
4.5 DEMETHANIZER OVERHEAD PRESSURE CONTROLLER
In normal operation, i.e. two expanders in operation, Demethanizer overhead pressure is
controlled by manipulating 41/42/43-PV-537 at common suction line of brake compressors.
If one of turbo expander/ compressor tripped, the Demethanizer will operate at a higher
pressure. The Demethanizer overhead pressure controller 41/42/43-PIC-537 kept in AUTO
mode will fully open 41/42/43-PV-537. In this case, Demethanizer overhead pressure is not
controlled by 41/42/43-PIC-537, rather it would be determine by the hydraulic balance from
the suction pressure controller of the Sales Gas Compressor. All Demethanizer overhead gas
can be sent to SG compressor via running brake compressor and bypass line.
If two set of Expander / compressor trip, it is possible to produce off-specification of NGL,
operator should take appropriate action, e.g., shut down the train or reduce the NGL feed gas
rate.
4.6 ONE NGL RECOVERY TRAIN SHUTDOWN
When one of NGL trains is shutdown, Hawiyah and Haradh feed gas rate controlled by the
Total Feed gas flow limit controller. Refer to section 4.3.1.
5 PROCESS CONTROL
5.1 SALES GAS RECYCLE FOR START-UP
During Process Dry-out and Start-up, Sales Gas Recycle is utilized first before introducing
Haradh Gas (coming from DGA) to the Unit. To ensure that enough Sales Gas is used,
Selective Control method is applied. With this method the low Signal Selector 41-FY-002
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03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 2299 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
shall select the lower manipulative value between the input signal from pressure controller
41-PIC-003 and flow controller 41-FIC-002 (Both are located at the Sales Gas Line). Output
signal from 41-FY-002 is then used to manipulate control valve 41-FV-002 which controls
the flow rate of Sales Gas Recycle entering the Unit. Note that this line is normally no flow.
5.2 HAWIYAH FEED GAS FLOW RATE
Actual Hawiyah feed gas flow rate is measured by 4-*FIC-001. To get an accurate flow
indication, temperature 4*-TI-008 and pressure 4*-PI-014 is accounted for (calculated in
4*-FY-001A). Hawiyah feed gas flow rate indicated in 4*-FY-001A is pressure and
temperature compensated.
5.3 HARADH FEED GAS FLOW RATE
Actual Haradh feed gas flow rate is measured by 4-*FIC-004. To get an accurate flow
indication, temperature 4*-TI-015 and pressure 4*-PI-033 is accounted for (calculated in
4*-FY-004). Haradh feed gas flow rate indicated in 4*-FY-004 is pressure and temperature
compensated.
5.4 REGEN GAS FROM SALES GAS COMPRESSOR
Sufficient Regeneration Gas Flow is necessary to make sure that the Feed Gas Dehydrators
(B66-D-0102A~F) are effectively regenerated within the required Regeneration time. To
achieve this, during normal operation, flow controller 4*-FIC-101A will control the regen
gas flow rate. If the regen system pressure exceeds the preset value, pressure controller
4*-PIC-228 will reduce regen gas flow rate via low signal selector 4*-FY-101. Output
signal from 4*-FY-101 is then used to manipulate control valve 4*-FV-101 which controls
regen gas flow rate to B66-E-0103A/B or B66-E-0104. Note that during stand-by period (i.e.
no flow of regen gas), PIC-228 will close FV-101.
5.5 PROPANE REFRIGERANT FEED TO B66-E-0104
Temperature controller 4*-TIC-182 on regen gas line to B66-D-0102A~F is cascaded to
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03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 3300 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
slave level controller 4*-LIC-033 which manipulates control valve 4*-LV-033 at Regen
Gas Cooling Cycle Chiller (B66-E-0104) shell side inlet line. B66-E-0104 outlet Regen gas
temperature is controlled by maintaining the propane level and pressure in the exchanger
and hence its rate of boiling.
TC-LC cascade will be disconnected by dehydrator sequence via HS-173 except for cooling
period.
5.6 PROPANE VAPOR TO COMPRESSOR SUCTION DRUM
The Low Signal Selector 4*-TY-195 shall select the lower manipulative value between the
input signal from temperature controller 4*-TIC-195 on the Regen gas line or temperature
controller 4*-TIC-196 on the liquid propane line. Output signal from 4*-TY-195 is then
used to manipulate control valve 4*-TV-195 which controls the flow rate of propane vapor
from Regen Gas/Propane Chiller (B66-E-0107) to Refrigerant 2nd Stage Compressor
Suction Drum (B66-D-0113AB). Outlet Regen gas temperature is controlled by maintaining
the propane vapor pressure in the exchanger and hence its rate of boiling.
5.7 DEMETHANIZER RESIDUE GAS FLOW RATE
Actual residue gas flow rate from Demethanizer is measured by 4*-FI-289A. To get an
accurate flow indication, temperature (average between upstream, 4*-TI-431 and
downstream, 4*-TI-364 of FE-289) and pressure 4*-PIC-608 located in Demethanizer
overhead line is accounted for (calculated in 4*-FY-289). Residue gas flow rate from
Demethanizer indicated in 4*-FI-289B is pressure and temperature compensated.
5.8 DEMETHANIZER BOTTOMS
Level of Demethanizer (B66-C-0110) Bottoms is maintained by level controller
4*-LIC-127A by manipulating control valve 4*-FV-341 by cascade control with flow
controller 4*-FIC-341. 4*FV-341 located at Demethanizer Bottoms Pumps
B66-G-0113A/B discharge line controls the flow rate of NGL going to Surge Spheres
B67-D-0101A/B.
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03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 3311 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
At process upset, with Demethanizer bottoms level exceeding LIC-127A high set point,
level controller 4*-LIC-127B will open control valve 4*-LV-127B to divert NGL to
Cryogenic Burn Pit. Further increase in liquid level (exceeding LIC-127B high set point),
level controller 4*-LIC-127C will open control valve 4*-LV-128C to divert NGL to
Cryogenic Burn Pit.
5.9 DEMETHANIZER CHIMNEY TRAY #3
Level Controller 4*-LIC-123 cascades onto flow controller 4*-FIC-303 with positive bias
(calculated in 4*-FY-303). This controls the level in Demethanizer Chimney Tray 3 by
manipulating control valve 4*-FV-303. 4*-FV-303 located at Demethanizer Top Side
Reboiler Pumps (B66-G-0112A/B) discharge line controls the HC Liquid flow rate going to
Cold Gas Exchanger, B66-E-0112.
5.10 DEMETHANIZER CHIMNEY TRAY #2
Level Controller 4*-LIC-124 cascades onto flow controller 4*-FIC-316 with positive bias
(calculated in 4*-FY-316). This controls the level in Demethanizer Chimney Tray 2 by
manipulating control valve 4*-FV-316. 4*-FV-316 located at Demethanizer Bottom Side
Reboiler Pumps (B66-G-0111A/B) discharge line controls the HC Liquid flow rate going to
Warm Gas Exchanger, B66-E-0111.
5.11 DEMETHANIZER CHIMNEY TRAY #1
Level Controller 4*-LIC-125 cascades onto flow controller 4*-FIC-329 with positive bias
(calculated in 4*-FY-329). This controls the level in Demethanizer Chimney Tray 1 by
manipulating control valve 4*-FV-329. 4*-FV-329 located at Demethanizer Reboiler
Pumps (B66-G-0110A/B) discharge line controls the HC Liquid flow rate going to Feed Gas
Exchanger, B66-E-0110A/B.
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03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 3322 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
5.12 CHILLED COOLING WATER FOR B66-E-0117A/B
50-TE-018 is installed on NGL/Water Exchanger B67-E-0101A~E in order to have stable
NGL Product temperature. 50-TIC-018 output signal is split range:
a) X% - This signal is cascaded to slave flow controller 4*-FIC-404 to manipulate
control valve 4*-FV-404 located on the Chilled Cooling Water line from
Refrigerant / Water Subcooler, B66-E-0117A/B to B67-D-0103. This controls the
temperature of propane from B66-E-0117A/B by varying the flow rate of Chilled
Cooling Water.
b) X-100% - This signal is used to control the Chilled Water (Warm) Supply bypass
control valve 50-TV-018 to the chilled water return header.
On Temperature increase, first close 4*-FV-404 to reduce water flow to minimum flow of
B67-G-0105ABC, then open bypass control valve 50-TV-018.
Close
Open
TC-018
TV018FV404
0 X 100
5.13 HAWIYAH GAS CHILLER B66-E-0102 OUTLET TEMPERATURE CONTROL
(BA-543210.005)
The 41-TIC-003 cascades onto 41-LIC-002 to control 41-LV-002. Also 41-TIC-003 process
value is passed to 41-TY-005 to compare with 41-TIC-016. The temperature difference
between 41-TIC-003 and 41-TIC-016 will be shown on 41-TDI-005. If the temperature of
the Haradh stream to the mixer gets significantly warmer than the temperature of the
Hawiyah stream, condensation of water may take place. Any liquid water going to the
dehydrator beds will damage the mol sieve material. Therefore, the temperature difference
between the Hawiyah and Haradh streams going to the mixer is monitored by 41-TDI-005
and an alarm signal is initiated when the Haradh stream is more than 9 degF warmer than the
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03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 3333 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Hawiyah stream.
5.14 HARADH GAS CHILLER B66-E-0108 OUTLET TEMPERATURE CONTROL
(BA-543210.005)
Either lower MV of 41-TIC-018 or 41-TY-016 is selected at 41-TY-005 to control
41-TV016. During ESD condition, 41-TV-016 and 41-TXV-016 behave as well as control
description for control valve with SOV in 2.15.
5.15 TEMPERATURE CONTROL WITH WARM GAS EXCHANGER (B66-E-0111) &
2ND STAGE GAS CHILLER (B66-E-0114) (BA-543212.001/003/004)
The 2nd Stage Gas Chiller (B66-E-0114) outlet temperature (41-TI-312) cascade on outlet
temperature (41-TIC-292) of Warm Gas Exchanger (B66-E-0111) to control 41-TV-292.
During ESD condition, 41-TV-292 and 41-TXV-292 behave as well as control description
for control valve with SOV in 2.15.
6 COMPLEX CONTROL
6.1 NGL RECOVERY AREA B66 (3 TRAINS)
NGL Trains High Pressure Protection Control
Refer to P&ID: B66-A-BA-543210-001, B66-A-BA-543213-001, B65-A-BA-540691-002
and Figure 4.13.1 of this document.
Objective
Protect each NGL Train feed gas header from over-pressure by reducing the feed gas flow
rate from Hawiyah gas pipeline first and if the header pressure is still higher than the set
value, reduce the feed gas flow rate from Haradh gas pipeline.
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03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 3344 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Functional Description
The controls description that follows is for the NGL recovery Train1 only, but the control
scheme is the same for NGL Train 2 and NGL Train 3 only with different prefix for
instrument tag identifications.
The NGL train feed gas header High Pressure protection controller 41-PIC-499B receives
its PV from the Expander suction header pressure measurement 41-PT-499. The output of
41-PIC-499B is split via a split range calculator. Two outputs of the split range calculator
are connected to blocks 41-HIC-014 and 40-PY-499B.
Higher range split control signal to reduce feed gas flow rate from Hawiyah gas pipeline will
adjust setpoint of Max Hawiyah train feed flow limit controller, 41-HIC-014, when it is in
Cascade mode. Output of 41-HIC-014 will then pass through low signal selector,
41-FY-001 to finally control 41-FV-001.
When 41-HIC-014 is in Auto mode, the operator can set the maximum feed gas flow rate for
NGL train 1 at the SP of 41-HIC-014.
When 41-HIC-014 is in Manual mode, the operator can manually change HIC output signal
to override the output signal from 41-FIC-001 via low signal selector 41-FY-001.
Lower range split control signal from 41/42/43-PIC-499B to reduce feed gas flow rate from
Haradh gas pipeline will pass through low signal selector, 40-PY-499B. Output of
40-PY-499B will then adjust the SP of both 31-HIC-003 and 32-HIC-003 when it is in
Cascade mode. Output of 31/32-HIC-003 will then pass through low signal selector switch
31/32-FY-003 to finally control 31/32-FV-003.
When 31/32-HIC-003 is in Auto mode, the operator can set the maximum feed gas flow rate
for DGA train 1/2 at the SP of the HIC.
When 31/32-HIC-003 is in Manual mode, the operator can manually change HIC output
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03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 3355 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
signal to override the output signal from 31/32-FIC-003 via low signal selector
31/32-FY-003.
Operational and Implementation Aspects
NGL Train Header High Pressure Protection control scheme is required to be operational
during start up and normal operation.
In normal steady state, for Hawiyah pipeline feed gas control, low signal selector
41-FY-001 is cascaded to 41-HIC-014, which in turn cascaded to NGL Train High pressure
controller, 41-PIC-499B. While for Haradh pipeline feed gas control, low signal selectors
31/32-FY-003 are cascaded to low signal selector 40-PY-499B via 31/32-HIC-003
respectively. Low signal selector 40-PY-499B will select the lower value from
41/42/43-PIC-499B lower range output signals to control the feed gas rate to DGA trains
when one or more NGL Trains header pressure is too high.
NGL Train Header High Pressure Protection Controller: Operator to be able to decrease SP
down to an enforced low limit. The operator shall not have access to 41-PIC-499B
controller’s mode or set point enforced low limit. Only engineer can change the controller
mode or set point enforced low limit.
Crippled Mode Operation
Failure of the NGL Train gas inlet pressure input signal from 41-PIT-499, identified as a
“Bad Value” status in DCS, will cause an alarm and high pressure protection controller
41-PIC-499B to go to MANUAL mode, with the output remaining at the last good value
previous to transferring to MANUAL mode.
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_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 3366 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Figu
re 4
.13.
1: H
NG
L Tr
ain
Hig
h Pr
essu
re P
rote
ctio
n C
ontr
ol
Feed
Gas
from
Haw
iyah
AO/A
FS
42FV
-001
43FV
-001
41FY 001
42FY 001
43FY 001
41FI
C00
1
42FI
C00
1
43FI
C00
1
31FV
-003
32FV
-003
DG
A-1
B65
-C-1
01
DG
A-2
B65
-C-X
XX
31FY 003
32FY 003
31FI
C00
3
32FI
C00
3
Feed
Gas
from
Har
adh
41PI
C49
9A41
PIC
499B
41HI
C01
4
42HI
C01
4
43HI
C01
4
SR (N
OTE
1)
42P
IC49
9B
43P
IC49
9B
31HI
C00
3
32HI
C00
3
HN
GL-
1B
66-C
-110
0-X
%
X-10
0 %
NO
TES
: 1.
Typ
ical
for
HN
GL
Trai
n 1,
2 a
nd 3
Hig
h P
ress
ure
Pro
tect
ion
Con
trolle
r 4*P
IC-4
99B
.
Valv
eO
peni
ng [%
]
0
100
100
4*P
IC-4
99B
MV
[%]
x
4*FV
-001
31/3
2FV
-003
SR (N
OTE
1)
SR (N
OTE
1)
40PY
499B
HN
GL
Trai
n-2
HN
GL
Trai
n-3
HN
GL
Trai
n-2
HN
GL
Trai
n-3
X-10
0 %
0-X
%
X-10
0 %
0-X
%
SP SP SP
SP
SP
41FV
-001
AO/A
FS
AO/A
FS
AO/A
FS
AO/A
FS
Rev
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 3377 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Calculation
41-PIC-499B Output Split Range Calculation
When 41-PIC-499B.PV is less than the setpoint value, the High Pressure protection
controller, 41-PIC-499B, output signal is on the high side, 100%.
When process value is greater than or equal to the set value, Split range calculation block
should convert 41-PIC-499B higher range output signal, X% ~ 100% to 0% ~ 100% as input
signal to 41-HIC-014, and lower range output signal, 0% ~ X% to 0% ~ 100% as input
signal to low signal selector switch, 40-PY-499B.
Initializations
NGL Train Header High Pressure Protection controller, 41-PIC-499B SP shall not track PV
when it is in MANUAL mode.
Output of 41-PIC-499B should be configured to track the 41-HIC-014 setpoint, when HIC is
placed in MANUAL or AUTO mode. Upon switching 41-HIC-014 to CASCADE mode,
41-PIC-499B output should be initialize to 41-HIC-014 setpoint to prevent bumping of the
process.
No output pushback shall be configured for low signal selector 40-PY-499B when any of the
31/32-HIC-003 switched from AUTO or MAN mode to CASCADE. Upon switching
31/32-HIC-003 from AUTO or MAN mode to CASCADE, HIC SP should ramp slowly to
match MV of 40-PY-499B.
Anti reset windup (ARWU) shall be configured for NGL train feed flow controller
41-FIC-001 and feed flow override controller 41-HIC-014 to ensure bumpless transfer in
case HIC is overriding the FIC as follows:
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 3388 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Normally, 41-FIC-001 in control, 41-HIC-014 MV shall be initialized to the low selector
output value (41-FY-001.MV). When 41-HIC-014 in control, the NGL train feed flow
controller 41-FIC-001 MV shall be initialized to the low selector output value
(41-FY-001.MV)
Anti reset windup (ARWU) shall be configured for DGA feed flow controller
31/32-FIC-003 and Maximum DGA feed flow limit controller 31-HIC-003/32-HIC-003 to
ensure bumpless transfer in case HIC is overriding the FIC as follow:
Normally, 31/32-FIC-003 in control, 31/32-HIC-003 MV shall be initialized to the low
selector output value (31/32-FY-003.MV). When the 31/32-HIC-003 in control, the DGA
train feed flow controller 31/32-FIC-003 MV shall be initialized to the low selector output
value (31/32-FY-003.MV)
Special Consideration
Upon 41-FY-001 selecting signal from 41-HIC-014 for more than 10 seconds, and the mode
of 41-HIC-014 is in CASCADE, 42-FIC-001 and 43-FIC-001 will set to AUTO mode (one
shot signal) if it is in CASCADE. The Operator is responsible to switch 42/43-FIC-001
back to CASCADE when the operating condition is back to normal.
Maximum Hawiyah train feed flow limit controllers, 41/42/43-HIC-014, and Hawiyah train
feed flow controllers, 41/42/43-FIC-001 must have the same process variable range.
Similarly, Maximum DGA feed flow limit controller, 31/32-HIC-003, and DGA feed flow
controller, 31/32-FIC-003 must have the same process variable range.
6.2 NGL TRAIN EXPANDER INLET PRESSURE CONTROL
Refer to P&ID: B66-A-BA-543213-001/ 002/003/004, B68-BA-540838-003 and Section
9.2, 9.3 & 9.4: Appendix , Figure 7.2.2 & Attachment 1 & 2 of this document.
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 3399 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
The anti-sure control system for Brake Compressor will be implemented in the Unit Control
Panel (PLC) by compressor vendor (MTC) and the control narrative for its compressor will
be described in the vendor’s documents.(V-2158-201A-050).
Refer to P&ID: B66-A-BA-543213-001/ 002/003/004, B68-BA-540838-003 and Figure
4.13.2 of this document.
Objective
To maintain constant Inlet pressure to each NGL Train turbo expander by regulating the
total gas flow to expander and Demethanizer overhead feed flow through DeC1 Overhead
Exchanger via fixed flow ratio setter.
Functional Description
The controls description that follows is for the NGL recovery Train1 only, but the control
scheme is the same for NGL Train 2 and NGL Train 3 only with different prefix for
instrument tag identifications.
41/42/43-PIC-499A output goes through low signal selector, 41/42/43-PY-499A to
manipulate the 2 set of Turbo Expanders’ IGVs (41/42/43-HV-311, 330) or Expander
bypass JT valves (41/42/43-FV-237A, C) via expander/compressor control system.
The Demethanizer overhead feed flow controller, 41/42/43-FIC-238 receives its setpoint
from total feed flow 41/42/43-FIC-237 via fixed flow ratio setter, 41/42/43-FY-238. By this
ratio setter, the Demethanizer overhead feed flow through the DeC1 OVHD exchanger
(B66-E-0*13) via 41/42/43-FV-238 is maintained at a preset flow ratio of total gas flow to
the NGL train.
Total gas flow rate to Demethanizer (DeC1) is also limited by NGL train total flow
controller (41/42/43-FIC-237) via low signal selector, 41/42/43-PY-499A. When the limit
setpoint around 1,400 MMSCFD is exceeded, 41/42/43-FIC-237 will override
41/42/43-PIC-499A to manipulate the Turbo expander IGVs. This is to protect DeC1 from
operating at over the design capacity.
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 4400 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
If the sales gas (SG) compressor suction pressure exceeds its preset value due to one or more
of SG compressor trip, the SG suction header high pressure protection 90-PIC-016 via SG
compressor master pressure validation controller will override the signals from
41/42/43-PIC-499A and 41/42/43-FIC-237 via low signal selector, 41/42/43-PY-499A. In
this case, 90-PIC-016 will manipulate the opening of the turbo expander IGVs via
expander/compressor control system to reduce DeC1 overhead flow.
The control action of the SG suction header High Pressure protection 90-PIC-016 and
expander suction header High Pressure protection 41/42/43-PIC-499B are reverse (the
output of the controller will decrease if suction pressure measurement increases) and the
expander suction header pressure controller 41/42/43-PIC-499A is direct (output of the
controller will increase if pressure measurement increases).
Operator can limit the NGL train total gas flow rate during start-up or during normal
operation by changing the controller 41/42/43-FIC-237 setpoint.
The turbo expanders inlet header pressure is controlled at a pseudo setpoint value via
41/42/43-PIC-499A.
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 4411 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Exp
ande
rB
66-K
-110
A/B
DeC
1 O
VH
D E
xch
B66-
E-11
3
B66
-D-1
11E
xp F
eed
Sepa
TR3
SG C
ompr
esso
rB6
8-K-
101A
~D
CC
SLo
adSh
arin
g(H
OLD
)34 23 19
Chi
m1
Tray
1 -
10
Chi
m2
Tray
11
- 18
Chi
m3
Chi
m4
Chi
m5
#1#6#10
#10
#11
#15
#20
41PI
C49
9B49
9A41
PIC
237
41FI
C23
841
FIC
238
41FYRS
016
90PI
C
TR2
PV
SP
41-F
IC-0
04.M
V
HIGH
PRE
SSUR
EPR
OTEC
TION
41FV
-238
41FV
-237
A
41FV
-237
C
A B
Brea
k C
ompr
esso
rB
68-K
-110
A/B
B66-
E-1
01A
/BB6
6-E
-110
A/B
B66
-E-1
11/1
12
Rev
Dir
Rev
AC/A
FO
AO/A
FC
AO/A
FC
499A
41PY
Max
Tot
alFe
ed G
as
300
41HI
C30
141
HIC
PD
EHB
IAS
PP
FD
Har
adh
Max
Flow
Lim
it
Not
e 1
SP
NO
TE 1
: PY
499C
.MV
= P P
FD -
P DE
H b
ias
whe
re: P
PFD
= s
et P
ress
ure
as p
er P
FD
P
DE
H =
Bia
s du
e to
pre
ssur
e dr
op o
n de
hydr
ator
(-)
(+)
Rev
41HV
-311
41HV
-330
499C
41PY
41PY
Figu
re 4
.13.
2: H
NG
L Tr
ain
Expa
nder
Inle
t Pre
ssur
e C
ontr
ol
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 4422 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Operation and Implementation Aspects
The Turbo Expander/Brake Compressor Control System (CCS) is required to be operational
during start-up and normal operation.
During the plant start-up, flow controller, 41-FIC-238, may be operated in MANUAL mode
until the flow indication has stabilized. Once the gas flow to DeC1 Overhead Exchanger can
be reliably controlled in AUTO mode, 41-FIC-238 can be placed in CASCADE to the Ratio
setter, 41-FY-238.
In normal operation, turbo expanders inlet header pressure is controlled at a pseudo setpoint
value via 41/42/43-PIC-499A. 41/42/43-PIC-499A output goes through low signal selector,
41/42/43-PY-499A to manipulate the 2 set of Turbo Expanders’ IGVs (41/42/43-HV-311,
330) or Expander bypass JT valves (41/42/43-FV-237A, C) via expander/compressor
control system. The Demethanizer overhead feed gas flow controller, 41-FIC-238, is in
CASCADE mode with ratio setter 41-FY-238.
Crippled Mode Operation
Crippled mode operation occurs when some instrument fails. Usually this will be a failure of
feed flow or pressure measurement, as described below.
Failure of total DeC1 feed flow transmitter, 41-FIT-237
Failure of the flow signal resulting in a "Bad Value" parameter in DCS will result in placing
affected flow controller 41-FIC-237 and ratio setter block, 41-FY-238, in MANUAL, with
the output remaining at the last good value prior to transferring to MANUAL, and initiating
an alarm.
Failure of DeC1 Overhead feed gas flow transmitter, 41-FIT-238
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 4433 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Failure of the flow signal resulting in a "Bad Value" parameter in DCS will result in placing
affected flow controller 41-FIC-238 in MANUAL, with the output remaining at the last
good value prior to transferring to MANUAL, and initiating an alarm.
Failure of Expander Inlet pressure transmitter, 41-PT-499
Failure of the pressure signal resulting in a "Bad Value" parameter in DCS will result in
placing affected pressure controller 41-PIC-499A in MANUAL, with the output remaining
at the last good value prior to transferring to MANUAL, and initiating an alarm.
Calculation
DeC1 Overhead Feed Gas Flow Ratio Setter, 41-FY-238
Demethanizer overhead feed gas flow ratio setter, 41-FY-238 calculates the set point signal
for expander bypass flow controller 41-FIC-238 using the operator inputted ratio value and
the filtered process value of total gas flow rate to Demethanizer, 41-FIC-237.
[ ]PVFRMV 237-FIC41*1][238-FY-41 −=
where:
41-FY-238.MV = calculation block outputs to 41-FIC-238.SP
FR1 = calculation block input, ratio set by operator
41-FIC-237.PV = filtered NGL total gas flow rate to train 1
Note: Low pass filter shall be used for the process value of each NGL train feed flow
controller.
41/42/43-PIC-499A pseudo pressure setpoint value setter, 41-PY-499C
The 41/42/43-PIC-499A pseudo pressure set point value is calculated via
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 4444 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
41/42/43-PY-499C which consider the following:
41/42/43-PY-499C.MV = P499A (PFD Value) – PDEH
1. P499A (PFD Value) = 748 psig as per PFD
Engineer to provide input through 41/42/43-HIC-300
2. PDEH = a manual term to allow bias for aging desiccant higher pressure drop
If pressure drop on dehydrators is increased, the operator has to compare PDEH with
other trains and determine a PDEH bias value (from zero to a certain value) in order
to have same operating pressure at mixing point of Hawiyah and Haradh Gas on
three NGL trains. Same Pressure at mixing point of Hawiyah and Haradh Gas on
three NGL trains means that the gas flow from Haradh gas pipeline will be
equalized.
Operator to input through 41/42/43-HIC-301
PFIC004 = 41/42/43-FIC-004 output value (MV) in psig (the same range as
41-PIC-499A.SP)
If 41/42/43-FIC004.PV exceed its set point (Maximum Haradh Gas flow limit per
train), 41/42/43FIC004 output value will be increased. Via high signal selector,
41/42/43-PY-49D, 41/42/43-PIC499A.SP will increase to adjust the expander’s
IGVs to close. When expander IGVs adjust to close, 41/42/43-PIC499A.PV will
be increased to meet the setpoint. At the same time, Haradh gas flowrate will be
decreased. This control limits the maximum flow rate of Haradh gas to protect
from moisture of Haradh gas.
Initialization
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 4455 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Anti-reset windup (ARWU) shall be configured for NGL train expander inlet pressure
controller, 41-PIC-499A , SG compressor suction header pressure protection controller,
90-PIC-016, and NGL Train Max Total Feed gas flow controller, 41-FIC-237 to ensure
bumpless transfer in case one controller is overriding the other controllers as follows;
With 41-PIC-499A in control, SG suction header pressure control, 90-PIC-016 and NGL
Train Max Total Feed gas flow controller, 41-FIC-237 shall be set using the MV value of
41-PY-499A for ARWU.
With 90-PIC-016 in control, NGL train expander suction header pressure controller,
41-PIC-499A and NGL Train Max Total Feed gas flow controller, 41-FIC-237 shall be set
using the MV value of 41-PY-499A for ARWU.
With 41-FIC-237 in control, NGL train expander suction header pressure controller,
41-PIC-499A and SG suction header pressure controller, 90-PIC-016 shall be set using the
MV value of 41-PY-499A for ARWU.
Special Consideration
41-FIC-004 shall be a direct acting controller. 41-PIC-499A shall be forced to CASCADE
mode. Engineer and NOT Operator shall have access to 41-HIC-300 PFD set value and
41-PIC-499A controller’s mode. Operator shall have access to 41-HIC-301 set value as
Dehydrator’s pressure bias.
6.3 EQUAL DISTRIBUTION OF TOTAL HARADH FLOW ON NGL TRAINS
Refer to P&ID B66-A-BA-543210-001, and Figure 4.13.3 of this document.
Objective
To avoid overloading of the dehydration system by evenly distributing the total Haradh feed
gas to the three (3) NGL trains.
Functional Description
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 4466 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
[ ])67.459(*)6959.14.01441()67.459.00841(*)6959.14(*004-FIC41][004-FY-41
++−−+−−+−=
D
D
TMVPIMVTIPPVMV
At normal operation, where 3 NGL trains are operating, to avoid overloading the
dehydration systems by uneven distribution of Haradh feed, Hawiyah ratio setter,
41/42/43-FY-001B will be automatically adjusted to maintain a set value on Haradh flow to
each NGL train. Pressure and temperature compensated flow of 41/42/43-FIC-004 will be
calculated via 41/42/43-FY-004. Compensated flow from each NGL trains will be averaged
via 40-FY-003 and the calculated value will then be compared to individual NGL train
process value, 41/42/43-FY004.MV. The difference between compensated flow value and
average value (41/42/43-FY-004.PV-40FY-003) will then be used to automatically adjust
the ratio set via 41/42/43-FY-001B on corresponding Hawiyah flow through
41/42/43-FDC-010 controllers. For example, incase of Haradh gas flow exceeds above the
setpoint, ratio for setpoint of Hawiyah gas flow will be increased. By the pressure from
Hawiyah gas will control the Haradh gas flow rate to reduce Haradh flow to avoid over flow.
During Start-up, NGL train Hawiyah gas ratio setter, 41/42/43-FY-001B will be operated in
Auto mode and operator will set the initial ratio. Once the Three NGL trains are running and
operating in stabilized condition, the 41/42/43-FY-001B can be switch from Auto to
Cascade mode so that controller 41/42/43-FDC-010 will set the Hawiyah feed ratio.
Crippled Mode Operation
Failure of Haradh feed gas to NGL train flow signal, 41/42/43-FIT-004 resulting in a "Bad
Value" parameter in flow controller, 41/42/43-FIC-004, and will result in placing the
controllers 41/42/43-FIC-004 and 41/42/43-FDC-010 and calculation blocks,
41/42/43-FY-004, 41/42/43-FY-010 and 40-FY-003 in MANUAL mode, with the output
remaining at the last good value prior to transferring to MANUAL mode and initiating an
alarm.
Calculation
41-FY-004 Pressure and Temperature Flow compensation Calculation Block
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 4477 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
where;
41-FY-004.MV = P,T compensated volumetric Flow rate [MMSCFD]
41-FIC-004.PV = Raw measured volumetric Flow rate [MMSCFD]
41-PI-014.PV = measured pressure [psia]
41-TI-008.PV = measured temperature [degF]
DP = Orifice Design Pressure [psia]
DT = Orifice Design Temperature [degF]
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 4488 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Figu
re 4
.13.
3: E
qual
Dis
trib
utio
n of
Tot
al H
arad
h Fl
ow o
n N
GL
Trai
ns
Feed
Gas
from
Haw
iyah
Feed
Gas
from
DG
A1&
2(H
arad
h)
HN
GL
Trai
n-1
Har
adh
Max
Flow
lim
it
Rat
ioC
alcu
lato
r
RS41
FY00
1B NOTE
3
NOTE
3
NOTE
3
42FY
001B
43FY
001B
41FD
C01
0
42FD
C01
0
43FD
C01
0
41FY 010
42FY 010
43FY 010
40FY 003
AVE
42FI
C00
4.PV
43FI
C00
4.PV
NOTE
2
NOTE
1
3. D
CS
Log
ic s
hall
disa
ble
this
con
trol b
y ch
angi
ng th
em
ode
of ra
tio s
ette
r, 4*
FY00
1B fr
om C
AS
to A
UTO
and
keep
the
last
ratio
whe
n on
e N
GL
train
is s
hutd
own
2. 4
*FY
010
= 4*
FIC
004.
PV
-40F
Y00
3
NO
TES
: 1.
40F
Y-0
03(A
vera
ge) =
(41F
IC00
4.P
V +
42F
IC00
4.P
V +
43FI
C00
4.P
V) /
3
Ratio
SP
Dir
Dir
Dir
(-) (+)(-) (+)(-)(+)
40FI
C00
2
40FY
004
41FI
C00
4Re
v41
PI03
341
TI01
5
41FY 004
41PY
499C
Har
adh
Gas
Tota
l Flo
w
41FY
009
41FI
C00
1
AO/A
FS
SP41
FY 001
PV
41H
IC01
4
Rev
41PI
014
41TI
008
41FY
001A
40FY
002
Flow
Total
izer
Rat
ioC
alcu
lato
r
41FY
009
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 4499 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Operation and Implementation Aspects
40-FY-003 Calculation Block
This calculation block computes for the average feed gas flow rate to NGL trains.
40-FY-003.MV = (41-FY-004.PV + 42-FY-004.PV + 43-FY-004.PV) / 3
41/42/43-FY-010 Calculation Block
This calculation block computes for the difference between the process value of Haradh
feed gas to each NGL and the calculated average value, 40-FY-003.MV.
41-FY-010.MV = 41-FY-004.PV- 40FY-003.MV
42-FY-010.MV = 42-FY-004.PV- 40FY-003.MV
43-FY-010.MV = 43-FY-004.PV- 40FY-003.MV
Special Consideration
This control scheme is only functional when three NGL trains are all in operation.
When at least one train is shutdown or if the difference of the process value of one train from
the average value is more than 10%, DCS logic will disable this control by changing the
mode of 41/42/43-FY-001B Ratio Setter from “CAS” to “AUTO” and keep the last ratio
setpoint.
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 5500 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
6.4 DEMETHANIZER OVERHEAD PRESSURE AND BOTTOMS TEMPERATURE
CONTROL
Refer to P&ID B66-A-BA-543213-003/005/008/010, B66-A-BA-543212-001 and Figure
4.13.4 of this document
Objective
Maintain and adjust the overhead pressure and bottom temperature of the Demethanizer to
maximize NGL recovery with on-specification overhead and bottom products.
Functional Description
The controls description that follows is for Demethanizer, 41-B66-C-110, on NGL recovery
Train1 only, but the control scheme is the same for NGL Train 2 and NGL Train 3 only with
different prefix for instrument tag identifications.
The Demethanizer overhead pressure is controlled at preset value via 41-PIC-537 by
manipulating the control valve, 41-PV-537 at common suction line of the break
compressors, B66-K-0110A/B.
The Demethanizer bottom temperature and chimney tray #1 level is controlled by a
decoupling scheme. With this decoupling control scheme, the LIC125A-FIC329 cascade
controller with positive bias calculated by 41-FY-329 will simultaneously adjust TV-429A
and TV-429C in the same direction. When liquid level becomes higher than level set point,
LIC-125A will increase the set point of FIC-329 that will result in increased opening of both
valves. This way, chimney tray 1 level can be controlled without disturbing the liquid flow
ratio distribution between inlet to B66-E-0110A/B, pass C and its bypass line. Thus,
maintaining control of DeC1 bottom temperature.
The temperature controller, TIC-429, will simultaneously adjust TV-429A and TV-429C
but in opposite direction by equal flow amount. In this way, the flow liquid distribution can
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 5511 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
be adjusted between inlet to B66-E-0110A/B, pass C, and its bypass line without changing
the total flow. Thus, maintaining control of Demethanizer chimney tray 1 level.
When more duty is required, TIC-429 will open TV-429B (TV-429A is fully open and
TV-429C is fully close). In this case, DeC1 chimney tray 1 level may be affected.
41-LIC-125B low level over ride signal via low signal selector, 41-TY-429B will close
TV-429B.
Operation and Implementation Aspects
During the plant start-up, DeC1 overhead pressure controller, 41-PIC-537 and DeC1 bottom
temperature controller, 41-TIC-429, shall be operated in AUTO mode.
In normal operation, i.e, two expanders in operation, DeC1 overhead pressure controller,
41-PIC-537 and DeC1 bottom temperature controller, 41-TIC-429, shall be operated in
AUTO mode with preset value as set points
If the one of expander / compressor tripped, the Demethanizer will operate in a higher
pressure. The Demethanizer overhead pressure controller 41/42/43-PIC-537 kept in Auto
mode will fully open 41/42/43-PV-537. In this case, Demethanizer overhead pressure is not
controlled by 41/42/43-PIC-537, rather it would be determined by the hydraulic balance
from the suction pressure controller of the Sales Gas Compressor. All Demethanizer
overhead gas can be sent to SG compressor via running brake compressor and bypass line.
In normal operation, 41-TIC-429 output pass through a split range calculator, 41-TY-429
which converts lower range signal 0~50% to 0~100% and higher range signal 50~100% to
0~100%. The higher range signal will manipulate 41-TV-429B via low signal selector,
41-TY-429B.The lower range signal will manipulate 41-TV-429A and 41-TV-429C via
decoupling control scheme. The decoupling control scheme is controlling the Demethanizer
bottom temperature via 41-TIC-429 and Demethanizer chimney tray # 1 liquid level via
41-LIC-125.
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 5522 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
The decoupling control modes operate as follows:
Control Mode Valve Manipulated
TIC LIC-FIC TV-429A TV-429C
Man Man Operator via TIC.MV Operator via LIC-FIC.MV
Auto Man TIC FIC.MV jumps to TV-429C
position and FIC.MV connects
to TV-429C.
Man Auto/Cascade TIC.MV jumps to
TV-429A position and
TIC.MV connects to
TV-429A
LIC-FIC
Auto Auto/Cascade TIC and LIC-FIC TIC and LIC-FIC
In the case that one expander/ compressor trips, a trip signal will activate logic, to
automatically ramp up the setpoint of DeC1 bottom temperature controller, 41-TIC-429 to
produce on-spec bottoms products. If the tripped Expander/Brake Compressor is recovered
from trip condition and put back on service, the Operator is responsible to ramp the set point
of TIC-429 toward normal operating point.
If two sets of the expander/compressor trip, it is possible to produce off-specification NGL.
The operator should take the appropriate action such as reducing the NGL feed gas rate and/
or shutting down the NGL train.
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 5533 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Figu
re 4
.13.
4: D
emet
hani
zer O
verh
ead
Pres
sure
and
Bot
tom
Tem
pera
ture
Con
trol
Expa
nder
B66-
K-01
10A/
B
DeC
1 O
VH
D E
xch
B66-
E-01
13
B66-
D-0
111
Exp
Feed
Sep
a
SG C
ompr
esso
rB6
8-K-
0101
A~D
41FV
-238
41FV
-237
A/C A&
B
B66-
E-10
1A/B
Brak
e C
ompr
esso
rB6
6-K-
110A
/B
NN
F
A
B
ESD
Log
icZC
AO/A
FS
537
41PI
C
34 23 19
Chi
m1
Tray
1 -
10
Chi
m2
Tray
11
- 18
Chi
m3
Chi
m4
Chi
m5
#1#6#10
#10
#11
#15
#20
B66-
G-0
110A
/BD
eC1
Reb
oile
r Pum
p
Feed
Gas
Exc
hB
66-E
-011
0A/B
429
41TI
C
Aux
iliary
Reb
oile
rB
66-E
-011
8
125A
41LI
C
AC/A
FO
AO/A
FC
41PV
-537
Dir
Dir
Rev
Feed
Gas
(Hot
Gas
)
41FV
-326
A/32
7AAC
/AFO
326A
/7A41
FIC
RevNN
F
B66-
E-01
11/0
112
B66-
D-0
110
NOTE
1
AC/A
FS41
TV-42
9A
AO/A
FC
Hot
Ref
riger
ant
Ref
riger
ant
NNF
429B
41TY
41LIC
125B
LL
329
Rev
41FI
C
SP
AC/A
FS41
TV-4
29C
41TV
-429
B
NOTE
1
NOTE
1 100%
100% 0
X %
100 %
TIC-
429.M
V [%
] X %
0
TV-4
29A
FIC3
29.M
V [%
]
VALV
EOP
ENIN
G[%
]
VALV
EOP
ENIN
G[%
]
30 d
egF
49 de
gF
78 de
gF
63 de
gF23
degF
Dem
etha
nize
rB6
6-C
-011
0
Low
Leve
l Ove
rride
TV-4
29C
TV-4
29A
TV-4
29B
TV-4
29C
SR
429
41TY
429A
41TY
429C
41TY 50
-100
%
0-50
%
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 5544 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Crippled Mode Operation
Crippled mode operation occurs when some instrument fails. Usually this will be a failure of
pressure or temperature measurement, as described below.
Failure of Demethanizer overhead pressure transmitter, PIT-537
Failure of the pressure signal resulting in a "Bad Value" parameter in DCS will result in
placing affected DeC1 overhead pressure controller, PIC-537, in MANUAL, with the output
remaining at the last good value prior to transferring to MANUAL, and initiating an alarm.
Failure of Demethanizer bottom temperature transmitter (TT-429) or RTD
Failure of the temperature signal resulting in a "Bad Value" parameter in DCS will result in
placing affected DeC1 bottom temperature controller, 41-TIC-429, in MANUAL, with the
output remaining at the last good value prior to transferring to MANUAL, and initiating an
alarm.
Failure of Flow transmitter (FIT-329)
Failure of the Flow signal resulting in a "Bad Value" parameter in DCS will result in placing
affected flow controller, 41-FIC-329, in MANUAL, with the output remaining at the last
good value prior to transferring to MANUAL, and initiating an alarm.
Failure of DeC1 Chimney Tray #1 Level transmitter (LIT-125)
Failure of the DeC1 Chimney Tray #1 level signal resulting in a "Bad Value" parameter in
DCS will result in placing affected level controller, 41-LIC-125A and 41-LIC-125B, in
MANUAL, with the output remaining at the last sound value prior to transferring to
MANUAL, and initiating an alarm.
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 5555 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Calculation
41-TY-429 Split Range Calculation Block
Split range calculation block, 41-TY-429 shall convert 41-TIC-429 higher range output
signal, 50~100% to 0~100% as input signal to low signal selector, 41-TY-429B and lower
range output signal, 0~50% to 0~100% as input signal to calculation blocks, 41-TY-429A
and 41-TY-429C.
41-TY-429A Calculation Block
100/).42941*100(.32941.42941 MVTYkMVFICMVATY −−∗−−=−−
where :
designA
designB
PP
CvACvBk
∆∆
= = 0.24
429A-TV-41 of valueCvCvA = = 550
429C-TV-41 of valueCvCvB = = 130
drop pressure 42941 designATVP designA −−=∆ = 500 psi
drop pressure 42941 designCTVP designB −−=∆ = 500 psi
41-TY-429C Calculation Block
100/).42941.32941(.42941 MVTYMVFICMVCTY −−∗−−=−−
41 FY-329 Calculation Block
41 –FY-329.MV = 41-LIC-125A.MV * Positive Bias (Range: 0.5 ~ 1.5)
Initialization
PV tracking option shall be provided for both 41-TIC-429 and 41-FIC-329 to initialize the
SP by PVs when the controllers are in Manual mode.
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 5566 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
If first controller (TIC or LIC-FIC) mode is changed from Manual to Auto, both controller
output values shall be back calculated from the current valve opening value for bumpless
transfer.
If next controller (LIC-FIC or TIC) mode is changed from Manual to Auto, the controller’s
output value shall be kept at current value and only the SP shall be initialized by its PV.
Special Consideration
Upon one expander/ compressor trip, a logic block, 41-ZC-427/432 will automatically ramp
up the setpoint of DeC1 bottom temperature controller, 41-TIC-429 to77degF at a rate of
measuring Temperature valve
6.5 B66-E-102 CHILLER OUTLET TEMPERATURE CONTROL
Refer to P&ID: B66-A-BA-543210-002/005 and Figure 4.13.5 of this document.
Objective
To maintain temperature of Hawiyah Feed gas at B66-E-102 chiller outlet.
Functional Description
The chiller outlet temperature is maintained by heat transfer rate of the chiller. The heat
transfer rate is controlled by varying the level of chiller refrigerant (propane), thus changing
surface area of gas carrying tubes in contact with the boiling liquid refrigerant. The chiller
level control is cascaded with chiller Hawiyah gas outlet temperature control. A change in
the process gas feed rate to the chiller will result in a change in chiller Hawiyah gas outlet
temperature. The chiller Hawiyah gas outlet temperature controller, 41-TIC-003 will then
change the setpoint of chiller propane refrigerant level controller, 41-LIC-002 to adjust the
propane refrigerant flow to chiller.
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 5577 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
The temperature of Hawiyah gas is compared to Haradh gas temperature where the
difference is calculated by 41-TY-005. When warmer Haradh gas is detected, alarm via
41-TDI-005 will be initiated.
Operational and Implementation Aspects
B66-E-102 chiller outlet temperature control scheme is required to be operational during
start up and normal operation
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 5588 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Figu
re 4
.13.
5: B
66-E
-102
Hea
t Chi
ller O
utle
t Tem
pera
ture
Con
trol
C3
Ref
riger
ant
B66-
E-11
7A/B
41LV
-002
Haw
iyah
Gas
B66-
E-10
1A/B
Haw
iyah
Gas
to S
tatic
Mix
er
C3
Vapo
rto
B66
-D-1
13A
/B
003
41TI
C
002
41LIC
Haw
iyah
Gas
Chi
ller
B66-
E-10
2
SP
MV
AO/A
FS
005
41TY
41TI
C-0
16.P
V
Note
1
005
41TD
IH
NO
TE 1
: Com
pare
the
tem
pera
ture
bet
wee
n H
awiy
ah a
nd
H
arad
h G
as. W
hen
war
mer
Har
adh
gas
is d
etec
ted,
Ala
rm v
ia T
DI-0
05 w
ill b
e in
itiat
ed.
PV
From
Fig.
7.2.
6
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 5599 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Crippled Mode Operation
Failure of chiller level signal resulting in a "Bad Value" parameter in DCS will result in
placing level controller 41-LIC-002 in MANUAL, with the output remaining at the last
good value prior to transferring to MANUAL, and initiating an alarm.
Failure of chiller exit temperature signal resulting in a "Bad Value" parameter in DCS will
result in placing temperature controller 41-TIC-003 in MANUAL, with the output
remaining at the last good value prior to transferring to MANUAL, and initiating an alarm.
Calculations 41-TY-005 Calculation Block 41-TY-005.MV = 41-TIC-016.MV – 41-TIC-003.MV Where: 41-TIC-016.MV = Hawiyah gas chiller outlet temperature 41-TIC-003.MV = Haradh gas chiller outlet temperature
Initializations
The output of 41-TIC-003 shall track SP of 41-LIC-002 when 41-LIC-002 is placed in
MANUAL or AUTO mode. When 41-LIC-002 is placed in CASCADE, 41-TIC-003 MV
initializes to 41-LIC-002 SP to prevent bumping of the process.
6.6 B66-E-108 CHILLER OUTLET TEMPERATURE CONTROL
Refer to P&ID: B66-A-BA-543210-002/005, Figure 4.13.6 of this document.
Objective
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 6600 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
To maintain temperature of Haradh process gas at B66-E-108 chiller outlet.
Functional Description
The chiller outlet temperature is maintained by heat transfer rate of the chiller. The
B66-E-108, chiller heat transfer rate is controlled by varying the propane refrigerant vapor
outlet rate to B66-D-113A/B. The refrigerant level is maintained constant by 41-LIC-013,
while the propane refrigerant vapor pressure (and associated refrigerant boiling rate) is
varied by the outlet gas temperature control loop 41-TIC-016 via the chiller backpressure
valve, 41-TV-016.
A change in Haradh feed gas flow rate to the chiller will result in a change in chiller Haradh
gas outlet temperature as detected by 41-TIC-016 as process value. The chiller Haradh feed
gas outlet temperature controller, 41-TIC-016 controls the valve position for C3R
backpressure control valve, 41-TV-016 via low signal selector, 41-TY-016.
To prevent hydrate formation in Haradh Gas due to low temperature, the propane refrigerant
inlet temperature controller 41-TIC-018, will also manipulate 41-TV-016 via the low signal
selector, 41-TY-016. When 41-TIC-018.PV (refrigerant temperature) becomes less than
41-TIC-018.SP, 41-TIC-018 closes 41-TV-016 via LSS (41-TY-016).
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 6611 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
C3
Ref
riger
ant
B66-
E-11
7A/B
41LV
-013
Haw
iyah
Gas
to S
tatic
Mix
er
C3
Vapo
rto
B66
-D-1
13A/
B
016
41TI
C
013
41LI
C
Har
adh
Gas
Chi
ller
B66
-E-1
08H
arad
h Fe
edG
as
AO/A
FS
018
41TI
C
MV
41TV
-016
Dir
Dir
AO/A
FS
016
41TY
41TY
-005
Note
1
PVTo
Fig
. 7.2
.5
NO
TE 1
: Min
imum
C3
Ref
riger
ant T
empe
ratu
re O
verr
ide
Con
trolle
r
t
o av
oid
hydr
ate
form
atio
n in
Har
adh
Gas
.
Figu
re 4
.13.
6: B
66-E
-108
Hea
t Chi
ller O
utle
t Tem
pera
ture
Con
trol
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 6622 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Operational and Implementation Aspects
B66-E-108 chiller outlet temperature control scheme is required to be operational during
start up and normal operation
Crippled Mode Operation
Failure of chiller exit temperature signal resulting in a "Bad Value" parameter in DCS will
result in placing temperature controller 41-TIC-016 in MANUAL, with the output
remaining at the last good value prior to transferring to MANUAL, and initiating an alarm.
Initializations
B66-E-108 chiller outlet temperature controller 41-TIC-016 and C3 refrigerant inlet
temperature controller 41-TIC018 shall be configured with anti reset windup (ARWU)
function. The function allows the output of 41-TIC-016 to track MV of Lower Signal
Selector (LSS) 41-TY-016 when 41-TY-016 is placed in MANUAL mode. When
41-TY-016 is placed in AUTO, 41-TIC-016 [MV] initializes to 41-TY-016 MV to prevent
bumping of the process.
6.7 TEMPERATURE CONTROL WITH B66-E-111 EXCHANGER AND B66-E-114
CHILLER
Refer to P&ID: B66-A-BA-543212-001/002/003/004/005, Figure 4.13.7 of this document.
Objective
To control NGL trend pressure, and to extract cooling from residue gas at B66-E-0111 up to
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 6633 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
a level to achieve the same B66-E-0111 feed gas outlet temperature as the outlet
temperature of Core-In-Kettle Chiller, B66-E-0114.
Functional Description
The NGL Feed gas trend pressure is controlled at preset value via 41-PIC-362 by
manipulating the feed gas flow to 2nd stage feed gas chiller B66-E-0114 via 41PV-362.
To match the outlet temperature of the 2nd stage feed gas chiller, B66-E-0114 and the outlet
temperature of pass A of B66-E-0111 warm gas exchanger, the setpoint of TIC-292 is set by
the 2nd stage feed gas chiller outlet temperature, 41-TI-312.
The control valve 41-TV-292 located on the inlet of pass A line of B66-E-0111, is
manipulated by the temperature controller 41TIC-292.
Temperature of the mixed feed gas is measured at the inlet to the chiller separator
B66-D-0110 via 41-TI-308 with high alarm.
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 6644 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Chi
ller
Sep
arat
orB6
6-D
-011
0
B66-
E-01
01A/
B
Feed
Gas
Exc
hB6
6-E-
0110
A/B
Figu
re 4
.13.
7: T
empe
ratu
re C
ontr
ol w
ith B
66-E
-011
1 H
eat E
chan
ger a
nd B
66-E
-011
4 C
hille
r
41TV
-292
287
41TI
AC/A
FO
2nd
Stag
e Fe
edG
as C
hille
rB6
6-E-
0114
War
m G
as E
xch
B66-
E-01
11
41PI
T
163B
41FI
163
41FI
362
41PI
C
B66-
D-0
104A
~E
C3
Econ
omiz
erB6
6-D
-011
541
LV-0
88
088
41LIC
B66-
E-01
12
41PV
-443
A
AC/A
FO
AO/A
FC
Dir
Rev
C3
Ref
riger
ant
Con
dens
erB6
6-E-
0115
A
1st S
tage
Cap
acity
& L
oad
Shar
eC
ontro
ller
1st S
tage
Suct
ion
Dru
mB6
6-D
-011
2A
B66-
K011
1A
41PV
-362
AC/A
FO
B A C
B A C
+63°
F
+78°
F+3
0°F
+23°
F-1
3°F
-9°F
-9°F
-14°
FAC
/AFO
41PV
-443
B
C3
Ref
riger
ant
Con
dens
erB6
6-E-
0115
B
1st S
tage
Suct
ion
Dru
mB6
6-D
-011
2B
B66-
K011
1B
443
41TI 308
443
41PI
41TI
312
Rev
41TI
C29
2
H
SP
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 6655 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Operation and Implementation Aspects
During Start-up, Operator will manipulate 41-TV-292 and 41-PV-362 in manual mode until
the mixed flow temperature on 41-TI-308 reads acceptable temperature. Once the system
stabilizes, 41-TIC-292 will be changed from Manual mode to Auto mode and control
41-TV-292. 41-PIC-362 in Auto mode will control 41-PV-362. High Pressure protection
will be dependent on the Over all master control.
When mixed flow temperature reading on 41-TI-308 exceeds the acceptable temperature
range, High alarm will be enabled and operator to change the C3 refrigerant compressor
suction pressure controller’s setpoint to adjust the C3 refrigerant temperature.
NGL trend pressure control and B66-E-0111 and B66-E-0114 gas outlet temperature
control scheme is required to be operational during normal operation.
Crippled Mode Operation
Failure of dehydrated gas pressure signal 41-PIT-362 resulting in a "Bad Value" parameter
in dehydrated gas pressure controller, 41-PIC-362, and will result in placing the controller
41-PIC-362 in MANUAL, and initiating an alarm.
Failure of warm gas exchanger B66-E-0111 feed gas exit temperature signal 41-TIT-292
resulting in a "Bad Value" parameter in DCS will result in placing temperature controller
41-TIC-292 in MANUAL, and initiating an alarm.
7 REGENERATION /ABSORPTION LOGIC SEQUENCE DESCRIPTION
There are six (6) Feed Gas Dehydrators (B66-D-0102A/B/C/D/E/F) in the NGL train.
During normal operation, Five (5) Beds are in Absorption Mode and one (1) in Regeneration
Mode. For instance, while dehydrators A/B/C/D/E are in normal operation (adsorption
mode), dehydrator F is in regeneration mode.
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 6666 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
The major process variables, which control and optimize the process in the dehydration
section, are described below.
Feed Gas Flow Rate
The water to be adsorbed during an adsorption cycle of the Dehydrators is directly
proportional to the flow rate of the feed gas. At low feed flow rates the accumulation of
water on the molecular sieve beds will occur more slowly and could theoretically allow for
longer adsorption cycle times. However, in practice the adsorption time will normally be
kept constant.
Feed Gas Temperature
The temperature of the mixed-feed gas exiting the static mixer directly influences the water
load on the Dehydrators. An increase in the temperature of the feed gas leaving the mixer
increases the water contents in the vapor phase (kg-H2O/m3), and therefore, this influences
adsorption cycle time.
The outlet temperature of the mixed-feed gas is controlled by two temperature controllers
located on separate feed gas chillers. Propane cooled chiller is provided each for the Haradh
feed gas and the Hawiyah feed gas. The temperature of each feed gas is maintained at 80
degF. After cooling the two streams, they are mixed in the static mixer.
Feed Gas Pressure
If the feed pressure is increase, the water content remaining in the feed gas leaving the
chiller is reduced. In normal operation, however, the pressure is stable and the pressure
fluctuation effects can be ignored.
Operational Description
For Ease of understanding, the discussion below describes steps undergone specifically by
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 6677 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Feed Gas Dehydrator A (B66-D-0102A) but also applies to Dehydrators B/C/D/E/F.
The dehydrators sequence consists of the following operation.
7.1 ADSORPTION PHASE: 54 HOURS
The wet gas enters the dehydrator and flows downwards; this step lasts 54 hours.
A water analyzer (4*-AI-045) is installed at the outlet of each dehydrator with a high alarm
keeping the operator informed about the water concentration in the dry gas, and avoiding
water breakthrough in the Gas Chilling section.
7.2 PRESSURIZATION: 10 MINS
a. Disconnect dehydrator from Adsorption (Step1)
At the end of the adsorption phase, the dehydrator-A is isolated by closing the KV valves
(41/42/43-KV-043, 41/42/43-KV-055, 41/42/43-KV-046 and 41/42/43-KV-057) at
dehydrator inlet/outlet lines at the same time. Also, AXV-045 at the sampling line for
41/42/43-AI-045 closes at the same time.
b. Dehydrator pressurization (Step2)
Then the inlet KV valve (41/42/43-KV-147) of Regen Gas Hot Water Heater
(B66-E-0103A/B) and outlet KV valves (41/42/43-KV-160 and 41/42/43-KV-165) of
Regen Gas Electric Heater (B66-E-105A/B) will be opened. The dehydrator is then
slowly pressurized to the regeneration gas operating pressure by opening the pressuring
line through pressure control valve (41/42/43-PV-075) thus preventing any bed
movement. Dehydrator pressure, controlled by pressure controller 41/42/43-PIC-075,
will increase (ramp up: 10 minutes) set point from 780 psig to 902 psig.
41/42/43-PIC-079 set point for 41/42/43-PV-079 is 991 psig to prevent PV-079 opening.
41/42/43-PIC-075 and 41/42/43-PIC-079 set pressure are changed by DCS Dehydrator
Logic for regeneration operation when KV make up is finished. Pressurization of
dehydrators is complete when PDIT (41/42/43-PDI-565) measures a 15 psi or less
difference between dehydrator and the Regen Gas pressure. The PV (41/42/43-PV-075)
is only used for pressurization and will be closed by controller when 902 psig is reached.
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 6688 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
The close limit switch of 41/42/43-PV-075 is included to permissive to go to next step.
c. Connect dehydrator to Regeneration (Step3)
Then the regeneration gas inlet (41/42/43-KV-047 and 41/42/43-KV-058) will be opened
at first, and outlet KV valves (41/42/43-KV-056 and 41/42/43-KV-044) of the dehydrator
will be opened next and heating step will proceed. Regeneration gas flow to the
dehydrator is up-flow (from bottom to top). Change TIC152 SP from 43 degF to 144
degF when this step is started. Also it overrides 41/42/43-PIC-075 SP to 780 psig to keep
close 41/42/43-PV-079.
7.3 HEATING: 385 MINS
a. 1st Ramp-up temperature (Step4): 10mins
After the pressurization of the dehydrator and connected dehydrator to regeneration,
regeneration gas temperature (41/42/43-TIC-152) set point is increased (ramp up: 10
minutes) from 144°F to 248°F using the Regen Gas Hot Water Heater (B66-E-103A/B).
Regeneration gas flow rate is controlled by low selection of either flow controller
(41/42/43-FIC-101A) or pressure controller (41/42/43-PIC-228) located on the inlet line
to B66-E-0103A/B. Temperature of Regen gas is controlled by temperature controller
(41/42/43-TIC-152) by varying the flow rate of MP hot water through control valve
41/42/43-TV-152 on the MP hot water line. During this step, Regen Gas Electric Heater
(B66-E-105A/B) is not on service. Also, inlet and outlet KV valves (41/42/43-KV-175
and 41/42/43-KV-176) of Regen Gas Cooling Cycle Chiller (B66-E-0104) are closed.
With the increase in Regen gas temperature, the dehydrator temperature
(41/42/43-TI-082) will also increase. The dehydrator temperature will increase from
79°F to 200°F.
b. 1st Stage Regeneration (Step5): 30 mins
When the temperature reaches 248°F at B66-E-103A/B outlet, which is controlled by
41/42/43-TIC-152, it is kept at this temperature for 30 mins before proceeding to 2nd
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 6699 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Ramp-up
c. 2nd Ramp-up temperature (Step6): 15mins
At 2nd Ramp-up Regen Gas temperature (41/42/43-TIC-152) set point at B66-E-103A/B
outlet is ramped up from 248°F to 400°F within 10 mins.
Regen Gas Electric Heater (B66-E-0105A/B) is also started via 41/42/43-HY-158/163
after 10mins of Step 6, and Regen Gas temperature (41/42/43-TI-164/169) is increased
further from 400°F to 550°F.
Note: The temperature control of B66-E-0105A/B is performed by Control Panel
supplied by Heater Vendor.
d. 2nd Stage Regeneration (Step7): 320 mins
When the temperature reaches 550°F at B66-E-0105A/B outlet (41/42/43-TI-164/169), it
is kept at this temperature for 320 mins. The regeneration gas flow rate is maintained as
the previous step. As Hot Regen Gas passes through the dehydrator, water adsorbed in
the bed is evaporated and mixed with the Hot Regen Gas. PV of 41/42/43-TI-082 should
be higher than 528°F and keeps the temperature 5 min within 320 min before go to next
step.
Before step-7 Dehydrator Heating is completed, the Dehydrator outlet temperature
(41/42/43-TI-082) to the Regen Gas Air Cooler (B66-E-0106) shall be confirmed in DCS
that it is sufficiently heated up to 528°F and the Heating Completed status
(41/42/43-YL-104) shall be indicated in DCS. In case it is below 528°F after step-7, the
Heating Not Completed and message “Please confirm to continue the dehydrator
sequence” shall be generated in DCS. Operation mode shall be changed to MANUAL
mode automatically. After then the operator can select from the three types of operation.
One is to stop the sequence. Other is to continue the sequence without excess Heating
Step. The other is to continue the Heating Step. In order to stop the sequence, the Stop
Sequence (41/42/43-HS-103) shall be used. To continue sequence without excess
Heating Step, operator shall change operation mode to AUTO mode. To continue
_____
| |
| |
_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 7700 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Heating Step, an operator shall keep the MANUAL mode and Heating step manually
e. Ramp down (Step8): 10 mins
Once the 2nd Stage Regeneration step is over, Regen Gas Electric Heaters
(B66-E-0105A/B) are turned off and 41/42/43-TIC-152 set point is decreased (ramp
down:10 minutes) from 400°F to 144°F.
7.4 COOLING (STEP9): 133 MINS
Once the heating step is over, the regen gas is then diverted to Regen Gas Cooling Cycle
Chiller (B66-E-0104) by opening KV valves (41/42/43-KV-175 and 41/42/43-KV-176).
Also, 41/42/43-LIC-033 cascade to 41/42/43-TIC-182.
After confirming that these KV valves at inlet and outlet of B66-E-0104 are completely
open, KV valves (41/42/43-KV-147, 41/42/43-KV-160 and 41/42/43-KV-165) around
B66-E-0103A/B and B66-E-0105A/B are closed. The regeneration gas flow rate is
maintained as the previous step. Regen Gas temperature (41/42/43-TIC-182) from Sales
Gas Compressor is cooled down from 144°F to 90°F and will be used to cool the dehydrator
for 133 mins.
The set point of 41/42/43-TIC-152 is changed to 43°
7.5 DEPRESSURIZATION
a. Disconnect dehydrator from Regeneration (Step10)
At the end of the cooling phase, the dehydrator is disconnected from the regeneration gas
line by closing the relevant KV valves (41/42/43-KV-044, 41/42/43-KV-058,
41/42/43-KV-044 and 41/42/43-KV-056) at dehydrator inlet/outlet. Also,
41/42/43-TIC-182/41/42/43-LIC-033 cascade is disconnected.
b. Dehydrator Depressurization (Step11): 10 mins
The dehydrator is then depressurized to the Feed gas operating pressure by opening the
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03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 7711 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
depressuring line through changing set point of pressure control valve
(41/42/43-PV-079) to residue gas header. Dehydrator pressure should be carefully
decreased (ramp down: 10 minutes) from 991 psig to 821 psig to prevent any bed
movement. The PV is only used for depressurization and will be closed when 821 psig is
reached. Dehydrator pressure is controlled by pressure controller 41/42/43-PIC-079. Set
pressure is changed by DCS Dehydrator Logic for adsorption operation.
Depressurization of dehydrator is complete when PDIT (41/42/43-PDI-077) measures a
15 psi or less difference between dehydrator and the Feed Gas pressure. When this
pressure difference is reached the system will now proceed to stand-by mode.
7.6 STAND-BY TIME: 110 MINS (STEP12)
The system will wait until 110mins have elapsed before going to adsorption mode. 110 mins
of stand-by time will be changed and will depend on operating conditions because starting
time of next Step 13 is fixed. During sequence Manual mode, the operator can skip this step
anytime when operator pressed Go to Next step “41/42/43-HS-105” under his responsibility.
Such kind of operation is considered when one of dehydrator regeneration time exceeds 10.8
hr.
7.7 CONNECT DEHYDRATOR TO ADSORPTION (STEP13)
Prior to opening of the Feed Gas inlet and outlet KV valves (41/42/43-KV-043,
41/42/43-KV-055, 41/42/43-KV-046 and 41/42/43-KV-057), blowdown KV valve
(41/42/43-KV-053) will open to the wet hydrocarbon burn pit after 648 mins later starting
from Step 1. The 41/42/43-KV-053 will be closed after 30 second pass from detecting open
limit switch. This will ensure that accumulated free water, if any, in the Feed Gas line is
flushed out from the feed gas system. This will protect the dehydrator bed from degradation
due to free water carry-over.
Normal operation
1) Regeneration and Adsorption sequence step
One cycle of the regeneration is 648 minutes (10.8 hrs) and consists of the following 14
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SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 7722 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
steps. Once sequence passes through Step 0, the Step 0 cannot be reached again during
normal sequence operation in Auto Mode except in case of 5 Dehydrators modes and
skipped.
Step Description Regen Gas
Temp. (°F)
Time
(Minutes)
0 Initialization - -
1 Disconnect Dehydrator from
Adsorption
- -
2 Dehydrator Pressurization - 10
3 Connect Dehydrator to Regeneration - -
4 Dehydrator Heating – Ramp up (1st
stage)
144 248 10
5 Dehydrator Heating (1st stage) 248 30
6 Dehydrator Heating – Ramp up (2nd
stage)
248 400
550
15
7 Dehydrator Heating (2nd stage) 550 320
8 Disconnect Regen Gas Electric Heaters
(B66-E-0105A/B) from Regeneration
- -
9 Dehydrator Heating – Ramp down 400 144 10
10 Dehydrator Cooling 90 133
11 Disconnect Dehydrator from
Regeneration
- -
12 Dehydrator Depressurization - 10
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SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 7733 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
13 Standby time - Approx.
110-
14 Connect Dehydrator to Adsorption -
Total - 648
NOTE 1: Each step timers can be extended anytime.
NOTE 2: Standby timers can be skipped by the operator when it is manual mode.
2) Automatic operation
The dryer sequence shall have two operation modes, Auto and Manual selectable by the
Auto/Man Selector Switch (41/42/43-HS-104). When it is in Auto position, Start
Sequence (41/42/43-HS-100) shall start the sequence, which always starts from
Dehydrator A in regeneration and Dehydrator B, C, D, E and F in adsorption mode. The
regeneration process shall move from one step to another in sequential order from A, B,
C, D, E and F and continue until it is stopped by the Stop Sequence (41/42/43-HS-101).
As the sequence starts in Auto mode, all the sequence related valves are initialized to
close position and then the sequence continues step by step. During AUTO sequence
operation, sequence gives open/close command to KV, change the controller setpoint
and turn on/off electric heater automatically. When a sequence is in Auto mode, the
operator must not manually manipulate any sequence valve. If operator wants to
manipulate the discrepancy valve, the Sequence Manual mode should be selected by
operator and changes controller mode to Manual individually. The timer for each step is
keep counting to proceed to next step. The transition to next step will be done
automatically if all permissive condition is cleared.
All individual valve position status, both open and close, shall be repeated to DCS and
the sequence monitors all the time that they are in the appropriate position as the
sequence programmed. If there is a discrepancy between the sequence command and the
actual valve position or a discrepancy between the start/stop command for Electric
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03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 7744 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Heater and it’s feed back, the sequence shall be turned to Sequence Manual mode and
allow to proceed the sequence manually by operator. The timer keeps counting and
generate the discrepancy alarm in DCS. It will continue to sending command to valves
until operator disconnect the valve from sequence by changing controller mode to
manual. After DCS receives the expected feedback of the sequence and all controller
modes is in AUTO, operator is able to put back Sequence mode to AUTO.
If the operator wants to stop the sequence intentionally by any reason, it is allowed to
stop the sequence using the Stop Sequence Switch (41/42/43-HS-101). In order to
resume the sequence from the stopped position, the Start Switch (41/42/43-HS-100)
shall be used.
The status of the Sequence Stopped (41/42/43-YL-102) shall be indicated in DCS when
it is stopped by the Stop Switch. (41/42/43-HS-101)
The mode status of each dehydrator if it is in regeneration or adsorption modes shall be
indicated in DCS by the Dehydrator Status (41/42/43-YI-100A/B/C/D/E/F). The timers
shall be indicated with the unit of “minutes”.
All timers and counters shall be available for operator in DCS graphic by the Phase
Timer.
The duration after depressurization to adsorption operation of the dehydrator is called
“Stand-by” mode, and therefore it is called Available Stand-by Time (41/42/43-KI-008).
The Stand-by time finishes by means of the timer when the total regeneration time is
expired (648 min. = 10.8 hrs).
3) Manual operation
During sequence Manual mode, the sequence also sends command to valves as well as
AUTO mode unless controller mode is changed to Manual by operator. The operator can
also change setpoint and MV.
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03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 7755 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
This manual mode operation is provided for trouble shooting of the sequence valve
position and for a step by step operation and not intended to manipulate a manual
operation of all the sequence valves. The step by step operation means the sequence can
not proceed to the next step automatically. Therefore, the Go to Next Step HS
(41/42/43-HS-105) shall be highlighted in DCS once all valve position matches to the
expected position in each step. The HS is not to be pressed until all permissive condition
is cleared, including timer. The sequence can start and stop during this manual mode.
Also, a series of the regeneration mode from step-1 through step-14 can be performed in
auto by the regen start switch (41/42/43-HS-100) without operator’s interference in this
manual mode.
4) Five (5) dehydrator’s operation (one dehydrator is out of service)
When one dehydrator is out of service, four (4) beds are in adsorption mode and one (1)
in regeneration mode. In this operation, the adsorption mode lasts for 54 hours, and one
cycle of the regeneration is 13.5 hours (Only stand-by time changes to 4.7 hours instead
of 110 minutes.) The total feed gas flow rate shall be reduced to 80% in this operation.
To change to the five dehydrator’s operation, the selector switch for five dehydrator’s
operation (41/42/43-HS-107) and the selector switch for a skipped dehydrator
(41/42/43-HS-108 A/B/C/D/E/F) shall be used any time. Once the selector switch for
five dehydrator’s operation is initiated, the DCS logic will be ready for switching, and
the five dehydrator’s operation starts when one of the dehydrators goes to step 13 “stand
by time” in regeneration mode by final command before step is moved to step 13, i.e.,
step-1. Any of five dehydrator operation command or skipped dehydrator command
during step 13 will be applied when next dehydrator’s step 13 is started.
8 PROCESS THEORY
The purpose of the Dehydration section is to remove water from the feed gas sent from the
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03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 7766 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Haradh and Hawiyah plants.
Feed gas drying is required:
• to meet the dryness specification for sales gas, i.e., water dew point.
• to prevent ice and hydrate formation in the Cryogenic section, which will cause
blockages in piping and equipment.
Dehydration section uses molecular sieves to remove the water from the feed gas.
Molecular sieves are a crystalline form of sodium alumina silicate (zeolite). They can be
manufactured with very specifically sized pore openings into their lattice structure. This
sizing can make the sieve very selective to which particular molecule it adsorbs.
Type 4A molecular sieves, which have a pore diameter of approximately 4 Angstroms
(100,000,000 A = 1 cm), are used in the Gas Dehydration section. They will basically adsorb
molecules with a nominal diameter less than 4A. The internal surfaces of molecular sieves
are electrically charged and are attracted to dissimilar changes on polar molecules. Water
molecules have a strong polarity and can be adsorbed onto 4A molecular sieves. It is
possible to reduce the water content in the outlet gas to less than 0.1 ppmv.
The purpose of the Mercury (Hg) Removal section is to remove trace quantities of mercury
present in the feed to the Cryogenic section, and this protects the Cold Box and
Turbo-Expander impeller made of aluminium against corrosion.
Eliminating mercury from hydrocarbon gas requires the use of a mercury trapping material
such as Activated Carbon. Mercury is trapped in the activated carbon and it is possible to
reduce the mercury content to less than 0.01 microgram/Nm3 of feed outlet gas. The
activated carbon is disposable, and when fully loaded with mercury, the bed must be
replaced with fresh material.
The purpose of the Cryogenic section and Demethanizer (C-0110) is to extract ethane and
heavier components as NGL from the Feed gas and at the same time to control High Heating
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03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 7777 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
Value of the residue gas to satisfy the sales gas specification. One of the cryogenic
expansion processes with parallel Turbo-Expanders (K-0110 A/B) is used for this unit. In
the cryogenic expansion process, a feed gas stream under high pressure is cooled by Brazed
Aluminum Heat Exchangers (BAHEs) with core in kettle type C3 Refrigerant Chiller
(E-0114). As the feed gas is cooled, liquids are partially condensed and collected in
separators as high-pressure liquids containing some of the desired ethane and heavier
components.
9 PROCESS VARIABLE
9.1 JOULE-THOMSON OPERATING MODE
The unit will be normally operated with two 50% Turbo-Expander. In case of one 50%
Expander shutdown, the Joule-Thompson valve installed on the by-pass line of the
Expander will be commissioned. The unit is designed to produce on-specification Sales Gas
considering one normal Expander operation and the other in Joule-Thomson operation.
1) Demethanizer Temperature
The operating temperatures of the train increases comparing with the normal 2
Turbo-Expander operation because of the lower thermal expansion effect through
Joule-Thomson valve.
2) Demethanizer Pressure
Since one of the Brake Compressor is bypassed in the residue gas line and the suction
pressure of Sales Gas Compressor in Unit B68 is maintained by a pressure controller, the
system operating pressure downstream of Joule-Thompson valve is higher than the
normal operation.
3) Demethanizer Feed Liquid Flow Rate
Liquid flow rate coming from the Chiller Separator and Expander Feed Separator
decreases due to higher temperature level in the Unit.
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_____INDRA
03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 7788 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
For One JT Operation 100% feed flow rate can handled in One JT operation.
Two JT operation is unstable operation with the current design. In order to satisfy the NGL
product specification of C1/C2 less than 2.5%, the feed gas rate at static mixer is reduced to
594.3 MMSCFD (44.9 % of design), because the current UA of B66-E-118 (0.274
MMBtu/F-hr including margin) is bottleneck. At this flow rate, tray load of Demethanizer
is significantly less than Demethanizer minimum turndown ratio (about 20% of normal
flowrate).
Therefore, during start-up, off-spec condensate is possible to be produced before one
expander is started-up. When two Expander/Compressors are tripped, off-spec condensate
is possible to be produced and unit shutdown will be initiated by operator manually.
9.2 FLOWRATE AT MIXER TO JT TRAIN (MMSCFD)
Flow/MMSCFD Total Hawiyah Haradh Normal 1322.9 100.0% 789.5 533.4 One JT 1322.9 100.0% 789.5 533.4 Two JT 594.3 44.9% 60.9 533.4
For Two JT operation, total 594.3 MMSCFD (44.9 % of design) can only be handled by design limit of Demethanizer auxiliary reboiler.
9.3 PRODUCT SPECS OF JT TRAIN
Normal One JT Two JT Heat content of residue gas BTU/SCF 930.0 960.9 997.0 Residue gas lbmol/hr 126,472 131,321 60,661 C1/C2 in NGL % 2.302 2.375 2.375 CO2 in NGL ppmV 464.1 175.0 179.5
% 95.65 56.28 27.62 Ethane Recovery lbmol/hr 18,730 13,881 4,543
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03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 7799 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
9.4 DEMETHANIZER
The temperature within the demethanizer will have a significant increase compared to normal
operation. Its overhead temperature will increase from -162.7 °F during normal to -125.4/
-104.9 °F (one/Two JT) and the bottom from 45.3 °F to 76.5/ 106.1 °F during One/ Two JT
Operation. This in turn will affect the whole train where residue gas is used as a cooling medium to
other streams.
The Overhead Pressure of the Demethanizer will increase from 263.1 psig during normal operation
to 307.7 psig during One & Two JT operation.
1) Temperature and pressure
OVHD Press(psig): 263.1 (Nor), 307.7 (One & Two JT)
OVHD Temp (degF): -162.7 (Nor), -125.4 (One JT), -104.9 (Two JT)
Bottom Press(psig): 267.5 (Nor), 312.1 (One & Two JT)
Bottom Temp (degF): 45.3 (Nor), 76. 5 (One JT), 106.1 (Two JT)
2) Feed Flow (Normal/One JT/Two JT):
From OVHD exchanger, E-0113/ lbmol/hr) 35,896/ 37,499/ 17,003
From Expander and/or JT valves, K-110/ lbmol/hr) 92,764/ 96,425/ 43,723
From Exp. Feed separator, D-111 / lbmol/hr) 12,013/ 7,866/ 3,422
From Chiller separator, D-110 / lbmol/hr) 4,529/ 3,412/ 1,055
3) Outlet Flow (Normal/One JT/Two JT):
C-110 OVHD/ lbmol/hr) 126,472/ 131,321/ 60,661.
C-110 Bottom/ lbmol/hr) 18,730/ 13,881/ 4,543.
4) Reboilers (Normal/One JT/Two JT):
B66-E-112 / lbmol/hr) 29,850/ 20,540/ 6,321
B66-E-111/ lbmol/hr) 23,585/ 18,133/ 5,949
B66-E-110A/B / lbmol/hr) 24,893/ 15,640/ no use
B66-E-118 / lbmol/hr) no use/ 3,203/ 5,109
For Two JT operation, tray load of Demethanizer is significantly lower than that of normal case and less than Demethanizer minimum turndown ratio. Therefore, Demethanizer cannot be stable
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03-OCT-2006
SSAAUUDDII AARRAABBIIAANN OOIILL CCOOMMPPAANNYY ((SSAAUUDDII AARRAAMMCCOO)) HHAAWWIIYYAAHH NNGGLL RREECCOOVVEERRYY PPLLAANNTT IINNSSTTRRUUCCTTIIOONN
PPLLAANNTT:: NNGGLL RREECCOOVVEERRYY TTRRAAIINNSS ((BB6666)) PPAAGGEE 8800 OOFF 8800 SSEECCTTIIOONN:: PPRROOCCEESSSS DDEESSCCRRIIPPTTIIOONN IINNSSTTRRUUCCTTIIOONN NNOO:: BB6666..0022 ____________________________________________________________________________________________________________________________________________________________________________________________
Issued: APR 2006 Revised: SEP 2006 Job No: 0-3850 Doc No: S-660-1283-001
operation with this conditions.
9.5 BLAZED ALUMINUM HEAT EXCHANGERS
The following figures shall be used for long period One/Two JT operation.
B66-E-0110A/B Hot gas outlet (degF): 30.0 (Nor), 39.2 (One JT), 50.0 (Two JT)
B66-E-0111&0114 Hot gas outlet (degF): -8.65 (Nor), -2.46 (One JT), 6.00 (Two JT)
Sprit flow ratio to E-114 (mol%): 41.61 (Nor), 41.90 (One JT), 48.00 (Two JT)
B66-E-0112 Hot gas outlet (degF): -56.56 (Nor), -41.70 (One JT), -35.00 (Two JT)
B66-E-0113 Hot gas outlet (degF): -159.3 (Nor), -110.4 (One JT), -97.0 (Two JT)
Sprit flow ratio to Expander & JT valve (mol%): 72.1 (Nor), 72.0 (One & Two JT)
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03-OCT-2006
Recommended