DIESEL HYDRODESULPHURISATION UNIT
CHAPTER-1 DESIGN BASIS 1/27
CHAPTER-1
DESIGN BASIS
1.1 GENERAL
Panipat refinery is designed to cater the demand of the petroleum products in the
northern region of India .The Panipat refinery consists of the following units:
1. Atmospheric and Vacuum Unit.
2. Once Through Hydrocracker Unit
3. Catalytic Reformer Unit
4. Resid Fluid Catalytic Cracking Unit
5. Hydrogen Generation Unit
6. Visbreaking Unit
7. Bitumen Blowing Unit
8. Amine Regeneration Unit
9. Sour Water Stripper
1.2 PURPOSE OF THE DHDS PROCESS
The DHDS unit is set up to reduce sulfur content in the diesel and produce diesel with
0.25% Sulphur.
The unit treats the following gas-oils fractions.
1. S.R.Gas oil
2. Vacuum Diesel
3. Vis-Breaker Gas Oil
4. Total Cycle Oil
1.2.1 Hydrodesulfurisation Section
The purpose of the section is to reduce 90% Sulphur in feed diesel using
hydrogen from Catalytic Reformer or Hydrogen Generation Units. In addition to
the deep desulfurisation, the diolefin and olefins will be saturated and a
denitrification will also occur.
The choice of catalysts and operating conditions is made in order to avoid
hydrogenation of the aromatics.
Feedstocks are blended from various sources, straight run or cracked products
Sulfur and nitrogen contents are depending upon the crude. Cracked products are
characterized by the presence of unsaturated hydrocarbons (olefins, diolefins and
aromatics)
Nowadays, more and more stringent specifications are imposed upon sulfur
content of diesel delivered by refineries.
DIESEL HYDRODESULPHURISATION UNIT
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Denitrification improves the product stability.
The required level of desulfurisation is achieved by hydrotreating over a specially
selected catalyst.
The presence of olefins or diolefins calls for additional bed installed in upstream
of the desulfurisation bed.
In the present case, no aromatic hydrogenation is aimed at.
The unit is able to produce treated Diesel Oil with maximum sulfur content of
500 ppm by providing an additional second Reactor in series.
1.2.2 Amine Treatment Section
The Amine Treatment Section is designed to remove Hydrogen Sulfide (H2S)
from gaseous hydrocarbons effluents.
H2S removal from gaseous hydrocarbons effluents is achieved by means of a
continuous absorption/regeneration process using a 25% wt. Di-Ethanol Amine
(DEA) for H2S removal.
This section includes the following main equipments
- HP Amine Absorber
- LP Amine Absorber
1.3 CAPACITY AND TURNDOWN RATIO
The DHDS unit is designed to hydrodesulfurise the two feedstock blends as in the
table named as “Feed 1” and “Feed 2” in section 1.4.1 and 1.4.2 respectively.
The characteristics of “Feed 3” used as check feed is given in 1.4.3.
The unit nameplate capacity is 700,000 MTPA with a stream factor of 8000 hours
per year. The design capacity is 770,000 MTPA.
The unit turndown rate is 50% of the design capacity
The design covers 2 cases:
In the case 1, 90% of the feed sulphur is converted to H2S.
In the case 2 with the installation of second reactor the sulphur in the feed is
reduced to 500 wt. ppm for the feeds 1 and 2.
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CHAPTER-1 DESIGN BASIS 3/27
The hydrogen required for the reactions is supplied either from the Catalytic
Reforming Unit or Hydrogen Generation Unit.
Lean Amine is supplied from the Amine Regeneration Unit
Nitrogen/air facilities for HR - 945 and HR-348 catalyst in-situ regeneration are
also provided.
The two feedstock blends are a mixture of:
Feed 1 : 87% wt. of SRGO and 13% wt. of SRVD
Feed 2 : 70% wt. of SRGO, 10% wt. of SRVD, 3% wt. of VBGO
and 17% wt. of CGO
Check Feed : 65% wt. of SRGO, 10% wt. of SRVD and 25% wt of
Total Cycle Oil
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CHAPTER-1 DESIGN BASIS 4/27
1.4 FEED SPECIFICATIONS
1.4.1 Feed 1
The characteristics of the feed 1 to be treated is as follows ((value)=estimated)
DESCRIPTION SRGO SRVD FEED 1
% on feed mix (wt) 87 13 100
Sp. Gr. 0.850 0.860 0.851
% S. wt. 1.53 2.48 1.65
Nitrogen ppm wt. 165 250 176
Cetane number 52.8 52.8 52.8
Flash point,
oC 81 100 (81)
Dist. ASTM.
oC
- IBP 226.5 276.2 226
- 05% 246 294 243
- 10% 265.4 312.5 269
- 30% 302.7 331.7 306
- 50% 316.9 340.7 321
- 70% 333.4 352.1 336
- 90% 359.7 366.8 362
- 95% 381 373.7 383
- EP 399 379.2 404
Metal content, wt ppm
- Nickel 0.07 0.07 0.07
- Vanadium 0.13 0.13 0.13
Name plate capacity : 7,00,000 T/y
Design capacity : 7,70,000 T/y
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CHAPTER-1 DESIGN BASIS 5/27
1.4.2 Feed 2
The characteristics of the feed 2 to be treated is as follows ((value)=estimated)
DESCRIPTION SRGO SRVD VBGO CGO FEED 2
% on feed mix (wt) 70 10 3 17 100
Sp. Gr. 0.850 0.860 0.859 0.869 0.854
% S. wt. 1.53 2.48 2.4 2.44 1.81
Nitrogen ppm wt. 165 250 500 675 270
Bromine number 34 27.4 5.6
Cetane number 52.8 52.8 38.9 38.6 -
Flash point,
oC 81 100 65 (67)
Dist. ASTM.
oC
- IBP 226.5 276.2 168 (178.6) 172
- 5% 246 294 199 - 212
- 10% 265.4 312.5 216 (202.6) 253
- 30% 302.7 331.7 248 (228) 293
- 50% 316.9 340.7 280 (252.6) 313
- 70% 333.4 352.1 307 (279.5) 331
- 90% 359.7 366.8 348 (313) 358
- 95% 381 373.7 361 - 380
- EP 399 379.2 407 (349.1) 403
Metal content.Wt ppm
- Nickel 0.07 0.07 - -
- Vanadium 0.13 0.13 - -
Name plate capacity : 700,000 T/y
Design capacity : 770,000 T/y
1.4.3 Feed 3
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CHAPTER-1 DESIGN BASIS 6/27
The characteristics of the feed 3 used as check feed are as follows
((value)=estimated)
DESCRIPTION SRGO SRVD TCO FEED 3
% on feed mix (wt) 65 10 25 100
Sp. Gr. 0.850 0.860 0.861 0.854
% S. wt. 1.53 2.48 0.74 1.43
Nitrogen ppm wt. 165 250 260 200
Bromine number 8.7 2.2
Cetane number 52.8 52.8 33
Flash point,
oC 81 100 36 (36)
Dist. ASTM.
oC
- IBP 226.5 276.2 141 141
- 05% 246 294 151 195
- 10% 265.4 312.5 162 220
- 30% 302.7 331.7 199 282
- 50% 316.9 340.7 240 312
- 70% 333.4 352.1 278 332
- 90% 359.7 366.8 341 362
- 95% 381 373.7 362 375
- EP 399 379.2 382 403
Metal content.Wt ppm
- Nickel 0.07 0.07
- Vanadium 0.13 0.13
Name plate capacity: 690,000 T/Y
1.5 MAKE-UP HYDROGEN SPECIFICATIONS
DIESEL HYDRODESULPHURISATION UNIT
CHAPTER-1 DESIGN BASIS 7/27
The hydrogen make-up is available at the battery limit with the following
composition:
a. Hydrogen from Catalytic Reforming Unit
Molar Composition Vol. %
H2 90.0
Cl 6.2
C2 1.6
C3 0.8
C4 0.7
C5 + 0.7
Impurities ppm v
Chlorine & Chloride 2 max.
b. Hydrogen from Hydrogen Generation Unit
Molar Composition Vol. %
H2 99.9
Cl 0.1
Impurities ppm v
CO + CO2 50 max.
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CHAPTER-1 DESIGN BASIS 8/27
1.6 ESTIMATED PRODUCT SPECIFICATIONS
1.6.1 Desulfurised Diesel
The Desulfurised diesel is produced at the stripper bottom and dried in the
coalescer before being sent to storage.
Description
Feed 1
Feed 2
Case 1 Case 2 Case 1 Case 2
SPGR 0.841 0.838 0.842 0.839
Sulfur content, wt. ppm 1650 500 1810 500
Nitrogen content, wt. ppm 110 70 160 110
Water content, wt. ppm <500 <500 <500 <500
Bromine Number <1 <1 <1 <1
Cetane index 58 59 57 58
Pour Point oC Same as feed Same as feed Same as feed Same as feed
Flash point oC Same as feed Same as feed Same as feed Same as feed
Color Same as feed Same as feed Same as feed Same as feed
1.6.2 Stabilized Naphtha
The naphtha recovered as liquid distillate from the stabilizer bottom is sent to the
naphtha storage.
Description
Feed 1
Feed 2
Case 1 Case 2 Case 1 Case 2
SPGR 0.750 0.748 0.750 0.747
H2S content wt ppm
Nitrogen wt ppm
max
10
2
5
1
10
2
5
1
RON 72 to 74 72 to 74 72 to 74 72 to 74
RVP 0.26 0.28 0.28 0.27
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CHAPTER-1 DESIGN BASIS 9/27
1.6.3 Sweet Fuel Gas from LP Amine Absorber
Sweet Fuel gas from LP amine is routed to FCC fuel gas header.
Description
Feed 1
Feed 2
Case 1 Case 2 Case 1 Case 2
H2 content, mol% 35 to 30 31 to 26 31 to 28 28 to 23
H2S content, ppm vol 100 100 100 100
H2O content, mol% 2 2 2 2
HC content, mol% 63 to 78 67 to 72 70 to 77 70 to 75
MW 19.3 to 20.9 20.4 to 22.4 20.3 to 21.6 21.2 to 22.9
1.6.4 Purge Gas from HP Amine Absorber
Normally this flow is zero.
1.6.5 Sour Water from Cold Separator
Description
Feed 1
Feed 2
Case 1 Case 2 Case 1 Case 2
NH4SH, wt% 1.0 1.7 1.6 2.5
This sour water is oversaturated with hydrocarbon and excess of H2S :
HC content : 600 wt. ppm
H2S content : 150 to 300 wt. ppm
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CHAPTER-1 DESIGN BASIS 10/27
1.7 CHEMICALS, CATALYSTS AND OTHER ITEMS
1.7.1 Anhydrous Ammonia
During in-situ catalyst regeneration under nitrogen/air atmosphere anhydrous
ammonia is injected at the reactor bottom at a rate of 100 wt ppm (compare to gas
at reactor inlet).
Properties:
Density, kg/m3 : 636
Viscosity, cP : 0.14
Molecular weight : 17
1.7.2 Dimethyl Disulfide(DMDS)
The Dimethyl Disulfide is injected at the feed pump suction at 1 wt % rate in the
recirculating gas oil, during catalyst sulfiding
Estimated DMDS consumption per catalyst sulfiding is about 3500 kg (Provision
for dense loading included).
1.7.3 Antifouling Agent
The antifouling agent is injected at the feed pump suction diluted at 10% in
straight run gasoil at the rate of 10 ppm of pure product compared to the feed.
Type : CHIMEC 3033 or equivalent
Estimated Annual consumption = 7700 kg
1.7.4 Antifoaming
The antifoaming is injected at the 52-PA-CF-107 suction, 52-CC-00-103 feed and
52-CC-00-104 feed, diluted at 10% in demineralised water at the rate of 20 wt.
ppm of pure product compared to each stream.
Type : CHIMEC 8039 or equivalent
Estimated annual consumption = 2400 kg
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CHAPTER-1 DESIGN BASIS 11/27
1.7.5 Corrosion Inhibitor Solution
The corrosion inhibitor is injected in the stripper and stabilizer overheads diluted
at 1% in stabilized naphtha at the rate of 6 wt. ppm of pure product compared to
the total column overhead.
Type : CHIMEC 1044 or equivalent
Estimated annual consumption = 600 kg
1.7.6 Caustic Soda Solution
During in-situ Catalyst regeneration under nitrogen/air atmosphere, a 10% wt.
Caustic soda solution is injected downstream of reactor effluent water cooler 52-
EE-00-104 at a rate of 0.7 wt.% of pure caustic (compare to gas at reactor inlet).
Estimated pure NaOH consumption per catalyst regeneration = 71,000 kg
1.7.7 Catalysts
Type : HR - 348 HR-945
Manufacturer : PROCATALYSE PROCATALYSE
Quantity :
Case 1 : 26.5 m3 3.3 m3
Case 2 : 61.1 m3 3.3 m3
1.7.7.1 Catalyst HR 348 1.2 Deep Hydrorefining of Petroleum Cuts
HR 348 1.2 presents very high denitrification and aromatic hydrogenation
activities as well as desulfurization activity better than common NiMo catalysts.
These features are particularly interesting in the treatment of feedstocks coming
from thermal and catalytic conversion processes.
It can be used in association with other NiMo type or CoMo type catalysts where
specific objectives are required.
HR 348 1.2 is either delivered under oxide form to be sulfided in-situ, or
presulfurized ex-situ by SULFICAT
process.
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CHAPTER-1 DESIGN BASIS 12/27
TYPICAL PROPERTIES
Nickel and molybdenum oxides on very high purity alumina
Cylindrical extrudates
Diameter
1.2
mm
Nickel (NiO) 3.3 Wt%
Molybdenum (MoO3) 16.5 Wt%
Total pore volume 0.42 Cm3/g
Sock loading density 0.72 Kg/l
Dense loading density 0.82 Kg/l
Bulk crushing strength 1.49 MPa
1.7.7.2 Catalyst HR 945 Hydrotreatment of Cuts Containing Olefins
HR 945 is a NiMo type catalyst to be used in front of hydrotreatment catalysts to
protect them against deactivation by unsaturated compounds generally contained
in cracked stocks.
HR 945 special design limits the polymerization of olefins and diolefins and
thus, the coke formation, even at low hydrogen partial pressure. The resulting
advantage is longer cycle operation.
It can be used in combination with any HR series catalysts.
HR 945 is either delivered under oxide form to be sulfided in-situ, or
presulfurized ex-situ by SULFICAT
process.
TYPICAL PROPERTIES
Nickel and molybdenum oxides on very high purity alumina
Spheres
Diameter 2 to 4 mm
Surface area 140 m2/g
Total pore volume 0.4 cm3/g
Tapped bulk density 0.88 kg/l
Bulk crushing strength 1.55 mini. MPa
1.7.8 Other Items
DIESEL HYDRODESULPHURISATION UNIT
CHAPTER-1 DESIGN BASIS 13/27
1.7.8.1 Absorbent
Type : Puraspec 2110 Puraspec 2240
Manufacturer : ICI-Katalco ICI-Katalco
Quantity : 1.9 m3 3.6 m3
1.7.8.2 Alumina Balls
Type : Mullite or equivalent
Quantity : 1/4” diameter Case 1 : 1.56 m3
Case 2 : 2.02 m3
3/4” diameter Case 1 : 2.08 m3
Case 2 : 3.27 m3
1.7.8.3 Ceramic Balls
Type : 1” ½ or 50 mm
Quantity : 0.3 m3
1.8 BATTERY LIMIT CONDITIONS - PROCESS
Operating Design
Temp.(oC) Pressure
(kg/cm2g)
Temp.(oC) Pressure
(kg/cm2g)
Feed from storage 40 5.0 95 15.0
Feed from CDU 65 5.5 95 22.0
Feed from VDU 74 6.3 95 17.0
Feed from VBU 133 18.8 150 26.0
Feed from FCCU 87 3.9 105 13.5
Make-up H2 (HGU) 40 19.5 55 27.5
Makeup H2 (CRU) 40 20 55 27.5
Sour Water 50 5.0 65 6.0
Rich Amine 66.4 6.9 80 12.8
Lean Amine 40 8.0 65 12.6
Diesel to Storage 40 6.0 55 16.6
Offspec Diesel 40 6.0 55 16.6
Stabilized Naphtha 40 5.0 55 10.1
Naphtha to Slop 40 3.5 150 10.1
Spent Caustic 55 2.0 70 21.0
Caustic Solution 40 9.0 65 17.0
Sweet FG to RFCCU 50 3.0 65 6.6
FO Supply 210 10 260 15.0
FO Return 210 5.3-1.9 260 15.0
Flare Header AMB ATM-1.5 150 65.0
1.9 BATTERY LIMIT CONDITIONS - UTILITIES
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CHAPTER-1 DESIGN BASIS 14/27
1.9.1 Steam and Condensate
Units Min. Normal Max. Mech. Design
Low Pressure
Pressure Kg/cm2g 3.0 4.0 5.0 7.0
Temperature
oC 143 175 190 240
Medium Pressure
Pressure Kg/cm2g 12.0 14.0 15.0 18.0
Temperature
oC 210 290 305 350
Condensate
Pressure Kg/cm2g 5.0 8.0 10.0 16.0
Temperature
oC 50 100 150 180
1.9.2 Cooling Water
Units Min. Normal Max. Mech. Design
Supply
Pressure Kg/cm
2g 3.8 - 4.5 7.0
Temperature
oC 33 65
Return
Pressure Kg/cm
2g 2.2 - 7.0
Temperature
oC 45 65
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CHAPTER-1 DESIGN BASIS 15/27
1.9.3 DM Water
Units Min. Normal Max. Mech. Design
Pressure Kg/cm
2g 4.0 7.5 8.0 12.0
Temperature oC Ambient 65
1.9.4 Boiler Feed Water
Units Min. Normal Max. Mech. Design
Pressure Kg/cm2g 28 40
Temperature oC 100-110 150
1.9.5 Nitrogen
Units Min. Normal Max. Mech. Design
Pressure Kg/cm2g 6.0 10.5
Temperature oC ambient 65
1.9.6 Service/Plant Air
Units Min. Normal Max. Mech. Design
Pressure Kg/cm
2g 7.0 10.0
Temperature
oC ambient 65
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CHAPTER-1 DESIGN BASIS 16/27
1.9.7 Instrument Air
Units Min. Normal Max. Mech. Design
Pressure Kg/cm
2g 7.0 10
Temperature oC 40 65
Dew Point at Atm. pressure = -40oC
1.9.8 Fuel Gas from B/L to Unit, from Unit to B/L
Units Min. Normal Max. Mech. Design
Pressure Kg/cm2g 3.0 3.5 6.2
Temperature oC 40 65
1.10.0 SITE DATA AND OTHER INFORMATION
1.10.1 Reference Documents
1) Survey of India Maps
2) Meteorological Data
1.10.2 Site Location
1 State where located Haryana
2 Nearest important town and distance Panipat
3 Nearest railway station and distance Panipat
4 Railway approach Gharonda
5 Nearest port -
6 Nearest airport and distance Delhi
7 Nearest highway milestone and distance NH-1
8 Approach road - Existing
- Planned
-
From NH-1, 8 km
DIESEL HYDRODESULPHURISATION UNIT
CHAPTER-1 DESIGN BASIS 17/27
1.10.3 Geographical Data
1 Geographic bearing of site -
2 Height above mean sea level 238 M
3 Bench mark level and location Plate no.136, 238.33
M.WL, Behind Canal Rest
House at app. S-1570.00
and W-140.00 co-ordinates
4 Site characteristics (Terrain Type) Flat land
5. Grade variation low point/high point 236.60 m/238.30 m
1.10.4 Meteorological Data
1 Climate of area Moderate
2 Air Temperature
Maximum/min. Dry bulb temperature 38.3
oC/6.8
oC
Design dry bulb/Wet bulb temperature 39
oC/27.5
oC
Ambient Temperature max./min. 46.6oC/(-)0.7oC
3 Rainfall
Maximum recorded in 1 hour 72 mm
Maximum recorded in 24 hours 218 mm
Annual max./min./Avg. 705 mm/307 mm/709.36
mm
Design intensity for surface 72
water drainage (MM/HR)
4 Rainy season June - September
5 HFL data for last 20 years and
maximum HFL recorded
237.72 m
6 Relative humidity – Maximum 94%
Normal
19%
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CHAPTER-1 DESIGN BASIS 18/27
7
Wind velocity and direction
- Wind velocity - Maximum 168 km/hr as a height of
30 mtr.
- Wind direction and % age Mor. SE (28.4%) to NW
(25.0 %), Eve.
NW(35.5%)to SE (27.0 %)
- Prevailing wind direction Mor SE to NW
Eve NW to SE
8. Barometric Pressure
- Maximum 988.4 mb
- Minimum 967.3 mb
- Average 978.675 mb
9. Earthquake design As per IS:1893 Zone IV
1.10.5 Site Grading
1.10.5.1 Design HFL for grading : 237.72 M
1.10.5.2 Borrow area location/details : Across Western Jamuna Canal
1.10.5.3 Proposed FGL : 237.72 / 238.02/238.32
1.10.6 Roads and Pavements
1.10.6.1 C.B.R. Value of soil:
1.10.7 Drainage
Storm water disposal point and
distance : To main drain no. 2 at RD 33650
Approx. distance from refinery: 800M
1.10.8 Water Supply
1.10.8.1 Source of water : Munak head works
1.10.8.2 Quality of water : Potable
1.11.0 OPERATING CONDITIONS AND YIELDS
DIESEL HYDRODESULPHURISATION UNIT
CHAPTER-1 DESIGN BASIS 19/27
1.11.1 Estimated ex-reactor yields (% wt. of liquid HC feed)
Feed 1
Description Case 1 Case 2
SOR MOR EOR SOR MOR EOR
H2S 1.59 1.59 1.59 1.7 1.7 1.7
NH3 0.008 0.008 0.008 0.013 0.013 0.013
C1 0.01 0.02 0.04 0.020 0.033 0.06
C2 0.02 0.03 0.05 0.020 0.036 0.07
C3 0.020 0.033 0.06 0.03 0.053 0.1
C4 0.020 0.036 0.07 0.03 0.053 0.1
C5 - 150 0.700 0.900 1.300 0.840 1.026 1.4
150+ 98.042 97.803 97.322 97.847 97.596 97.087
Total 100.41 100.42 100.44 100.50 100.51 100.53
H2 Chemical
Consumption
0.41 0.353 0.44 0.5 0.51 0.53
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CHAPTER-1 DESIGN BASIS 20/27
1.11.1 Estimated ex-reactor yields (% wt. of liquid HC feed) (Contd.)
Feed 2
Description Case 1 Case 2
SOR MOR EOR SOR MOR EOR
H2S 1.74 1.74 1.74 1.87 1.87 1.87
NH3 0.013 0.013 0.013 0.02 0.02 0.02
C1 0.01 0.02 0.04 0.02 0.036 0.07
C2 0.02 0.03 0.05 0.03 0.047 0.08
C3 0.020 0.033 0.06 0.03 0.056 0.11
C4 0.020 0.036 0.07 0.04 0.067 0.12
C5 - 150 0.7 0.9 1.3 0.90 1.117 1.55
150+ 97.997 97.758 97.277 97.70 97.407 96.82
Total 100.52 100.53 100.55 100.610 100.620 100.640
H2 Chemical
Consumption
0.52 0.53 0.55 0.610 0.620 0.640
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CHAPTER-1 DESIGN BASIS 21/27
1.11.2 Operating conditions
1.11.2.1 Reactor
Feed 1
Description Case 1 Case 2
SOR MOR EOR SOR MOR EOR
R01 inlet temperature, 0C 326 341 356 326 341 356
R01 outlet temperature, 0C 343 358 373 343 358 373
R01 WABT, 0C 335 350 365 335 350 365
Inlet pressure, kg/cm2 g 60.6 60.6 60.6 63.8 63.8 63.8
Outlet pressure, kg/cm2 g 56.6 56.6 56.6 59.8 59.8 59.8
R02 inlet temperature, 0C 330 345 360
R02 outlet temperature, 0C 338 353 368
R02 WABT, 0C 334 349 364
Inlet pressure, kg/cm2 g 59.6 59.6 59.6
Outlet pressure, kg/cm2 g 56.6 56.6 56.6
Space velocity 3.8 3.8 3.8 1.75 1.75 1.75
H2 recycle ratio, Sm3/m
3 150 150 150 150 150 150
H2 partial press., kg/cm2
Minimum recommended
35 35 35 35 35 35
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CHAPTER-1 DESIGN BASIS 22/27
1.11.2.1 Reactor (Contd.)
Feed 2
Description Case 1 Case 2
SOR MOR EOR SOR MOR EOR
R01 inlet temperature, 0C 323 338 353 323 338 353
R01 outlet temperature, 0C 346 361 376 346 361 376
R01 WABT, 0C 335 350 365 335 350 365
Inlet pressure, kg/cm2 g 60.6 60.6 60.6 63.8 63.8 63.8
Outlet pressure, kg/cm2 g 56.6 56.6 56.6 59.8 59.8 59.8
R02 inlet temperature, 0C 336 351 366
R02 outlet temperature, 0C 343 358 373
R02 WABT, 0C 340 355 370
Inlet pressure, kg/cm2 g 59.6 59.6 59.6
Outlet pressure, kg/cm2 g 56.6 56.6 56.6
Space velocity 3.8 3.8 3.8 1.75 1.75 1.75
H2 recycle ratio, Sm3/m
3 150 150 150 150 150 150
H2 partial press., kg/cm2
Minimum recommended
35 35 35 35 35 35
Feed 3 (check Feed) : The operating conditions are the same as for Feed 2 except
for space velocity which is increased by 10% due to the smaller flow rate.
The Space velocity (LHSV) is the volume of liquid HC feed at 15 0C in m
3/hr
divided by the volume of catalyst.
The hydrogen recycle ratio is a measure of the hydrogen recycle through the
furnace to the reactor entry. It is expressed as the standard m3/hr of pure H2
recycled divided by the volume of HC liquid feed in m3/hr at 15
0C.
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The minimum hydrogen recycle ratio = 150 Sm3/m
3.
The hydrogen partial pressure is measured at the reactor outlet.
The minimum hydrogen partial pressure = 35 kg/cm2.
1.11.2.2 Cold Separator
Temperature, 0C : 50
Pressure, kg/cm2 g : 50
1.11.2.3 Stripper
Stripper feed temperature, 0C : 262 to 265
Stripper reflux drum temperature, 0C : 40
Stripper reflux drum Pressure, kg/cm2 g : 5.0
Stripping ratio = Stripping steam (kg / h) : 22 to 24
Stripper feed (t / h)
Reflux ratio:
Feed 1 Feed 2
Description Case 1 Case 2 Case 1 Case 2
SOR EOR SOR EOR SOR EOR SOR EOR
Reflux / feed (% wt) 5.37 5.60 5.24 6.08 6.92 7.05 6.77 7.44
DIESEL HYDRODESULPHURISATION UNIT
CHAPTER-1 DESIGN BASIS 24/27
1.12.0 ESTIMATED UTILITIES CONSUMPTION
The following table gives estimated utility consumption for DHDS plant.
S.No. UTILITY CONSUMPTION
1 Cooling Water, m3/hr. 710
2 Boiler Feed Water Unit, kg/hr 500
3 D.M. Water, m3/hr. Intermittent use
4 Service Water, m3/hr. 10
5 Condensate flowrate(condensate pump) 2970
6 LP Steam consumed, kg/hr. 2260
7 MP Steam Consumed, kg/hr. 12130
8 Power Consumed, KW 1340
9 Fuel, MG Kcal./hr. 4.34
DIESEL HYDRODESULPHURISATION UNIT
CHAPTER-1 DESIGN BASIS 25/27
1.13 ESTIMATED CATALYST, ALUMINA BALLS, CERAMIC BALLS,
CONSUMPTION
1.13.1 Catalysts
Type : HR - 348 HR - 945
Manufacturer : PROCATALYSE PROCATALYSE
Quantity :
Case 1 : 26.5 m3 3.3 m
3
Case 2 : 61.1 m3 3.3 m
3
1.13.2 Alumina balls
Type : Mullite or equivalent
Quantity :
1/4” diameter : Case 1 : 1.56 m3
: Case 2 : 2.02 m3
3/4” diameter : Case 1 : 2.08 m3
: Case 2 : 3.27 m3
1.13.3 Ceramic Balls
Type : 1½“ OR 50 mm
Quantity : 0.3 m3
DIESEL HYDRODESULPHURISATION UNIT
CHAPTER-1 DESIGN BASIS 26/27
1.14.0 ESTIMATED CHEMICALS CONSUMPTION
1.14.1 Chemicals used during normal operation
S. No CHEMICALS CONSUMPTION
Kg/year
REMARKS
1 Corrosion Inhibitor 600 -
2 Antifouling 7,700
3 Antifoaming 2,400 -
1.14.2 Chemicals used during transient/catalyst regeneration operation
S. No CHEMICALS CONSUMPTION
Kg.
REMARKS
1 DMDS 6,400 Consumption per
catalyst sulfiding
2 Anhydrous Ammonia 580 Consumption per
catalyst regeneration
3 NaOH (pure) 71,000 Consumption per
Catalyst regeneration
DIESEL HYDRODESULPHURISATION UNIT
CHAPTER-1 DESIGN BASIS 27/27
1.15.0 WASTE EFFLUENTS
1.15.1 Off-gases to Atmosphere
1.15.1.1 Flue Gas from Fired Heater
Continuous flow : About 4000 Sm3/h. H2S content depends on FG quality.
1.15.1.2 N2 Bleed during regeneration
Once every 2 years. Duration : about 8 days
Flow rate : Max. 615 kg/h
Composition N2 : 91% wt.
CO2: 7% wt.
1.15.2 Aqueous Effluent
1.15.2.1 The sour water is the purge of the SWS unit.
1.15.2.2 Water from fired heater decoking
Once every 4 years. Duration about 2 days.
Content : Coke, SO2, H2S, NH3
1.15.2.3 Spent caustic during regeneration
Once every 2 years. Duration about 8 days.
Flowrate of water : 2440 kg/h
content (NH4)2SO4 : 12 kg/h
Na2CO3 : 210
Na2SO3 : 107
This spent caustic has to be sent to an oxidation plant with aeration by air in
presence of catalyst to oxidize the sulfites in sulfates.
1.15.2.4 Waste Water during Sulfiding
Once every 2 years. Duration about 8 hours.
Flow rate : 270 kg/h, H2S content : Up to 0.2% wt.