2 Basic New Handout

7/25/2019 2 Basic New Handout

1/42

1

1

SEPARATION THEORYFrom basic separation to ALCAP system


2/42

2

3

Separation efficiency is proportional

to settling area and inversely to Q

Inlet

Q

W

A

Separation effic iency

100

50

0A

Outlet

Basic separation

Separation effic iency100

50

0Q

4

Q = V Ag

Q = Throughput capacity, m3 /s

vg = Gravitational settling velocity, m/s

A = Settling area (l w), m2

Separation efficiency100

50

0Q

Throughput capacity directly proportional

to settling area and velocity

Inlet

Q

WA

Outlet

Continuous gravity separation


3/42

3

5

Basics!

The efficiency of all separating equipmentis a function of:

Flow rate

Settling area

Settling velocity

6

Continuous gravity

separation vessel

Increased efficiency.

Enlarged settling area by

means of buffer plates

Improving the gravity separation vessel


4/42

4

7

Separation by density difference

Density ~ 1000 kg/m3Continuous water phase

Oil droplet

Solid particle

Density < 1000 kg/m3

Density > 1000 kg/m3

8

Conventional separator

= a TANK


5/42

5

9


With liquid

10

With liquid &

solids



6/42

6

11

Separation of liquid & solids

only

What to do in order to getliquid / liquid / solid

separation ??


12

Install baffle

plates



7/42

7

13

Water seal

filled


14

Static separation of oil / water and

solids



8/42

8

15

Static separation with discs


16

Turning the

tank



9/42

9

17


18

Centrifugal Force

Centrifugal force; 1000s of G replacing the static 1 G



10/42

10

19

Feed to separator

Rotation of thetank

Light phase out

Heavy phase out

Gravity Disc

Level Ring

Solids out

Conventional separator= a rotating tank

20

2 Basic Separation principles

# 1: SEPARATOR arranged for PURIFICATION

OIL / WATER / SOLIDS INLET

CLEANED OIL OUTLET

WATER OUTLET

SOLIDS /SLUDGE

OUTLET

OIL is cleaned from water and sol ids

Dewatering of oils


11/42

11

21

# 2: SEPARATOR arranged for CLARIFICATION


OIL / SOLIDS INLET CLEANED OIL OUTLET

SOLIDS / SLUDGE

OUTLET

NOTE !

No Water Outlet

Water Outlet i s Closed

Solids are removed from OIL

Polishing of oils

22


= Continuous cleaning of oils wi th max. density

991 Kg/m3 / 15oC

= Continuous removal of solids from oils.

Water removal is limited

Dewatering of oils

A Gravity Disc is used to match actual working condit ion,

but it s size is depending on the density of the oil, theseparation temperature and the required flow over the

separator

A Clar if ier Disc is used to seal of f water outlet

Polishing of oils

purifier

clarifier


12/42

12

23

Conventional separator applications

Purifier Types for:

Clarifier Types for:

Fuel Oil Cleaning

- Lube Oil Cleaning

Hydraulic Oil Cleaning

Fuel Oil Polishing Hydraulic Oil Polishing

24

Some basics!

The oil, water and particles must beimmiscible!

Do not form a stable chemical mixture , like

gin/tonic

There has to be a density differencebetween the oil, water and particles


13/42

13

25

More basics!

The efficiency of all separating equipmentis a function of:

Flow rate

Settling area

Settling velocity

26

The disc-stack

The disc-stack

Short settling paths, large settling area

Caulk(s) 0,5 - 0,8 mm

The disc stack is the most

important part of theseparator, here the

separation of the dirt

particals takes place.

Should the disc stack

get dirty, or blocked

in some way, the separation

efficiency will be drastically

reduced


14/42

14

27

Flow between discs.

Caulk(s) 0,5 - 0,8 mm

The disc-stack

0,5 mm

FLOW

>5000 G

28

Flow between discs

The river!n Parabolic velocity profile:

friction close to wall -> lower

velocity

centre of tube -> higher velocity

A pipe.

Between discs

0,5 - 0,8 mm


15/42

15

29

1

2

1: G-Forces

2: Flow

Flow between discs

30

Flow between discs


16/42

16

31

Flow between discs

32

Flow between discs


17/42

17

33

Basic Separation principles

Purifier bowl

The disc-stack

Sludge

outlet

34

Clarifier bowl

- Oil inlet- Clean Oil outlet

- Closed Water

outlet

- Sludge

outlet

Basic Separation principles


18/42

18

35


36

Conventional separator:Conventional separator:

The purifierThe purifier

Factors affecting

interface position : 1

Density of oil decrease

Viscosity of oil decrease

Flow rate decrease

Temperature of oil

increase

- Water coming in

oil outlet

- Interface moving

towards centre:

- Water blocking

disc stack

- Risk for

Bad separationBad separation

Gravity disc too small


19/42

19

37

Density of oil increase

Viscosity of oil increase

Flow rate increase

Temperature of oil

decrease

Disc stack dirty

- Oil in Water outlet

= broken Water seal

- Interface moving

towards periphery

Risk forBroken WaterBroken Water--sealseal

Conventional separator:Conventional separator:


Factors affecting

interface position : 2

Gravity disc too big

38

How to find right GHow to find right G--disc:disc:



20/42

20

Separation Efficiency

Factors effecting separation

Efficiency

40

Separator Filter

Particles < 4 m 65-85 5-10

Cat fines 60-90 ~ 5Iron 40-60 ~ 5

Sodium 40-50 < 5

Average samples from 44 ships during normal operation

source Alfa Laval SMT/F 9402

Separation Efficiency (%)


21/42

21

41

Components in oils not effected by Separation

Density

Viscosity

CCAI

Flash point

Pour point

Micro Carbon Residue

Sulphur / Vanadium

Asphalthenes


42

Water

Sodium

Aluminium Silicone

Iron

Magnesium

Ash

Calcium

Cat-fines

Components in oils strongly effected by Separation



22/42

22

43

Water in separator bowl in general:

In order to get the best possible separation result

- Water must never enter the disc stack !!!


44

Conventional separator: The purifier

Purifier optimum interface position: 1

Outside the outer edge of the disc-stack

Inside the outer edge of the top-disc



23/42

23

45

Correct gravity disc size

Clean Disc-stack

Maintain following feed conditions:

Constant oil properties = viscosity & density Constant FLOW - rate

Constant TEMPERATURE


Purifier optimum interface position: 2


46


Sensitivity of interface position

for Mineral oils in

Marine & Diesel

appl.



24/42

24

47

Conventional separator system :

PURIFIER LIMITATIONS

The Gravity Disc

Maximum Density 991 kg/m3

Manual Adjustment

Optimum Separation hard to achieve

Need of qualified attention for optimum

result


48

NOTE :

All MAPX type separators and All MOPX / WHPX typeseparators from before 1984/85 have a density limitaround 985 kg / m at 15 C

Water separation with oil densities above this densitylimit will cause problems with this separators whenoperated as purifiers



25/42

25

49

Conventional separator system :

OPTIMUM SEPARATION RESULT on HFO

Maximum Density 991 kg/m3

PURIFIER followed by CLARIFIER

Operation in SERIES for optimum separation result

CLARIFIER act as SAFETY NET = POLISHER

CLARIFIER to be discharged at same interval as thepreceding purifier


50

Conventional separators:

Density limit = 991 Kg /

m3 / 15 oC

Viscosity l imit = 600 cSt /

50 oC


26/42

26

ALCAP THEORY

52

When the oil crisis of early 70 s happened , refineries

were forced to remove more and more light fractions

from the crude oil.To achieve this , a number of different distillation

methods were developed resulting in a HFO quality that

was to bad for conventional purifiers to clean. The

density of the oil got too high as well as the viscosity and

we were forced to develop better separation techniques.

This resulted in the so called ALCAP system.

Need to develop new type separators:


27/42

27

53

ALCAP type separators:

Working principle:

ALCAP means:

A = Alfa

L = laval

C = Clarifier

A = And

P = Purifier

It is a clarifier and a purifier

type separator in one

frame;

Giving the benefits (higher

separation efficiency) of the

clarifier and the water drain

capability of the purifier.

54

Working principle benefit.

Before the ALCAP was on the market , the treatment of

HFO was mostly done by means of purifier / clarifier in

series operation.

Meaning:

a purifier to remove the water and the larger dirt particles

from the oil, then this pre-cleaned oil was led to the

clarifier were it was polished( removing the smaller dirt

particles).

With the ALCAP this task is done in just one separator.



28/42

28

55

Working principle benefit

The ALCAP separator is actually a Clarifier , thus the

water removal capacity of the separator is very low as

the water outlet is closed.

In order to solve this we have installed a water drain

valve in the water outlet , thus giving the possibility to

drain out the water when required.

Therefore we could say that the ALCAP is basically aClarifier when in operation , but with the possibility to

remove the water during a temporary purifier function.

(opening the water outlet for a number of seconds)


56

Density limit = 1010 Kg /

m3

/ 15o

CViscosity limit = 700 cSt /

50 oC



29/42

29

57

- FOPX

- MFPX

- LOPX

Older types

- S type separators,

new type

ALCAP separators are:

58

Are Always part of an ALCAP system

This System consists of;

- The separator- The control unit

- The transducer in the clean oil outlet



30/42

30

59

SU configuration


MT : Transducer

PI : Pressure indicator

Pt 4 : Pressure transmitter

Back pressure regulation valve

RV4combined with shut-off

valve V4

Valve V5 in water outlet:

normally closed

Opens on signal from

control unit only

60

HANDLING of FUELS

FOPX configuration


Mt4 : Transducer

PI : Pressure indicator

PS : Pressure sensor

FI : Flow indicator

Valve V5 in water outlet:

normally closed

Opens on signal from

control unit only


31/42

31

61

Working principle

The basics of the ALCAP is the continuous supervision

of the cleaned oil quality.

The cleaned oil leaves the separator through the

transducer , this is a sensor that is continuously

measuring the percentage of water in the cleaned oil,

should this get too high , more then 0.2 % , the system

will take action to discharge the water.

This can be done via the drain valve V5 in the water

outlet , or by means of a sludge discharge cycle


62

Working principle

The water content in the oil is measured by comparing

the di electric constant of oil and water.

Oil has a constant of approx. 4-6Water has a constant of approx 90-95

This means that only a little amount of water will

drastically increase the reading of the oil constant and

thus indicates water in the oil.



32/42

32

63

Working principle

When a ALCAP system is started , as soon as oil is being fed into

the bowl , the system takes a reference value of the oil passing

through the transducer .This value is stored in the memory.

As we start with a clean bowl , we have the maximum efficiency

from the separation, so no water should be measured.

During separation , as sludge builds up in the bowl , some of the

water in the bowl will eventually be forced out with the clean oil.

This is measured with the transducer and signalled to the controller,the controller compares this value to the stored reference value and

if the deviation is to large the controller will take action to remove the

water from the bowl.


64

Working principle

The reading of the water amount in the cleaned oil is displayed in

the control system display in the form of picofarad(pF),

The stored reference value is also in pF , the signal that indicates

the increase of water is called the trigger and 100% trigger equals

a water increase of 0,2 %.

As soon as the measured trigger reaches 100% the controller will

take action to remove the water from the bowl , either by draining

through valve V5 or by initiating a sludge discharge cycle.

Should the measured water amount not decrease a alarm is

triggered and the operators will be notified that something is wrong.



33/42

33

65

Sludge

Water

Oil Interface

Bowl


66

Oil inlet

Oil outlet (normally open)

Water outlet (normally closed)

Sludge / solids

outlet

Conditioning and displacement water inlet


34/42

34

67

Transducer principle

FOPX / MFPX

68

Transducer principle FOPX / MFPX

Stored reference value 0.2 %water in

cleaned oil

Time between discharges ( 30 min.) timer 60 =10

minutes + timer 61 = 20 minutes

Ref. time

Time

Transducer valueAt start up

trigger

range

0%

100 %


35/42

35

69

Stored

reference

value

Time between discharges

Time

Transducer value

No 100% trigger

reached

Sludge discharge

sequence starts

No,or low water in the oil

Normal operation

trigger

range

0%

100 %

Timer 60, 10 minutes Timer 61, 20 minutes


70

Stored

reference

value

trigger

range

0%

timer 60 , 10 minutes

Time

Transducer value

Low to normal water in the oil (1)

Normal operation

100 %

Trigger 100%,drain

valve V5 in water

outlet opens

Trigger 80%,drain

valve V5 in water

outlet closes againafter 20 seconds

( valve may stay openfor max. 2 minutes)

Timer 61, 20 minutes



36/42

36

71

Stored

reference

value

trigger

range

0%

timer 60

Time

Transducer valueNormal operation

100 % Trigger 100%,

Sludge discharge

timer 61 , 20 minutes30 minutes

Low to normal water in the oil (2)


72

Stored

reference

value

trigger

range

0%Time

Transducer value

High water in the oil

Normal operation

100 %

Trigger 100%,drain

valve V5 in water

outlet opens

Trigger 80%,drain

valve V5 in water

outlet closes again

after 20 seconds

timer 60 , 10 minutes Timer 61, 20 minutes

Trigger 100%,

Sludge discharge



37/42

37

73

Stored

reference

value

trigger

range

0% Time

Transducer value

Very much water in the oil

Normal operation

100 %

Trigger 100%,drain valve V5 in water outlet opens and

stays open for two minutes, sludge discharge!

Again trigger 100%,drain valve V5 in water outlet opens

and again stays open for two minutes,Alarm A7-1 , feed-

valve in re-circulation

timer 60 , 10 minutes Timer 61, 20 minutes


74

FOPX / MFPX separators

Sludge discharge is based on

TRIGGER

But time takes over


38/42

38

75

Transducer principle

SU / SA

76

Storedreference

value

trigger

range 0.2%

Time between dischargesRef. time

Time

Transducer value

At start up

Transducer principle SU / SA


39/42

39

77

Stored

reference

value

Set time between discharges

Time

Transducer value

Sludge discharge

sequence starts

No,or low water content in the oil

Normal operation on Fuel oil

trigger

range

0%

100 %


78

Stored

reference

value

trigger

range

0%


Time

Transducer value

Normal water in the oil

100 %

Trigger 100%,drain

valve V5 in water

outlet opens

Trigger 70%,drainvalve V5 in water

outlet closes again

Normal operation on Fuel oil



40/42

40

79

Stored

reference

value

trigger

range

0%


Time

Transducer value

High water in the oil

100 %

Trigger 100%,drain

valve V5 in wateroutlet opens

Trigger 70%,drain

valve V5 in water

outlet closes again

Sludge discharge


80

Stored

reference

value

trigger

range

0%


Time

Transducer value

100 %

Trigger 100%,drain

valve V5 in water

outlet opens,trigger

does not drop to 70%

so drain valve

remains open for thepreset time, then

closes for 5 seconds

and opens again forthe other preset

times

Sludge discharge

Much water in the oil



41/42

41

81

Storedreference

value

trigger

range

0%


Time

Transducer value

100 %

Trigger 100%,drain

valve V5 in water outlet

opens, trigger stays

above 70% until time

for discharge or after

the preset number of

valve openings.

ALARM too high water

content in oil

Very much water in the oil


82

SU / SA separators

Sludge discharge is based on

TIME

But trigger takes over


42/42

83

Summary Continuous monitoring of the cleaned oil

Always optimum protection of the diesel engine

No gravity disc less operator dependent

Self adaptive

Single stage fuel oil treatment

Improved separation performance, ALCAP

always optimum cleaning result

very low oil losses at sludge discharge

84

Continuous monitoring of the cleaned oil

Full flow measurement

Variations in dielectric constant are detected

dielectric constant for mineral oil: 2 6

dielectric constant for water : 90-95

Always optimum protection of the diesel engine

Interface control no water or sludge in the cleaning area continuous monitoring of water content

Summary

Documents

2 Basic New Handout