2 Basic NewVIIx

8/6/2019 2 Basic NewVIIx

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SEPARATION THEORY

Basic separation

2

Separation efficiency is proportional

to settling area and inversely to Q

Inlet

Q

W

A

Separation efficiency

100

50

0A

Outlet

Separation efficiency100

50

0Q

Basic separation.


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3

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

Basic separation.

Gravity separation

4

The efficiency of all separating equipmentis a function of:

Flow rate

Settling area

Settling velocity

Basic separation.

Basics


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5

Density ~ 1000 kg/m3Continuous water phase

Oil droplet

Solid particle

Density < 1000 kg/m3

Density > 1000 kg/m3

Basic separation.

Density difference

6

Continuous gravityseparation vessel

Increased efficiency.Enlarged settling area bymeans of buffer plates

Basic separation.

Improving separation


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7

= a TANK

Basic separation.

Conventional separator

8

With liquid

Basic separation.



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9

Long sett ling distance Short settling distance

With liquid &solids

Basic separation.


10

What to do in order to getliquid / liquid / solidseparation ??

Separation of liquid & solidsonly

Basic separation.



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11

Install baffle plates

U- tube

Basic separation.


12

U- tube

Water seal filled

Basic separation.



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13

U- tube

Water seal filled

Basic separation.


14

Density

difference

I Svedberg / 02 09 12 Page 14BASICPURTHEORY.PPT

OilColumnheight

WaterColumnheight U- tube

Static separation of oil / water andsolids

Basic separation.



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15

Static separation

Oil surface

level weir

Fixed Oil surface level weir = The Level ring

Fixed

U- tube

Basic separation.


16

Static separation

U- tube

Densityweir

Oil surfacelevel weir

Adjustable heightDensity weir

= TheGravity disc

Adjustable

Fixed

Fixed Oil surface level weir = The Level ring

Basic separation.



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17

Static separation with discs

G forceG force

Basic separation.


18

Turning thetank

Basic separation.



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19Basic separation.


20

Centrifugal Force

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

Basic separation.



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21

Feed to separator

Rotation of the

tank

Light phase out

Heavy phase out

Gravity Disc

Level Ring

Solids out

Basic separation.


22

# 1: SEPARATOR arranged for PURIFICATION

OIL / WATER / SOLIDS INLET

CLEANED OIL OUTLET

WATER OUTLET

SOLIDS /SLUDGEOUTLET

OIL is cleaned from water and solidsDewatering of oils

Basic separation.

Separation principles


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23

# 2: SEPARATOR arranged for CLARIFICATION

OIL / SOLIDS INLET

CLEANED OIL OUTLET

SOLIDS / SLUDGEOUTLET

Solids are removed from OILPolishing of oils

NOTE !

Water Outlet is Closed

Basic separation.


24

= Continuous cleaning of oils with max.

density 991 Kg/m3 / 15oC

= Continuous removal of solids from oils.Water removal is limited

Dewatering of oils

Polishing of oils

Purifier

Basic separation.


Clarifier


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25

Purifier Types for:

Clarifier Types for:

Fuel Oil Cleaning

- Lube Oil Cleaning

Hydraulic Oil Cleaning

Fuel Oil Polishing

Hydraulic Oil Polishing

Basic separation.

Separator applications

26

Wear

Soot, ash

Acids

Other combustion

products

Water, sand, dirt

Air vent

Oil refill

Blow by

Combustion

Sn

PbCu FeCrCaSo4

Basic separation.

Clarifier in lube oil

Calcium carbonate

Calcium Sulfate


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The disc-stackCaulk(s) 0,5 - 0,8 mm

The disc stack is the mostimportant part of the

separator, here theseparation of the dirt

particals takes place.

Should the disc stack

get dirty, or blocked

in some way, the separation

efficiency will be drasticallyreduced

Basic separation.

The disc stack

28

The disc-stackCaulk(s) 0,5 - 0,8 mm

0,5 mm

FLOW

7000 G

Basic separation.

The disc stack


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29

The river!n Parabolic velocity profile:

friction close to wall -> lowervelocitycentre of tube -> higher velocity

A pipe.

Between discs

0,5 - 0,8 mm

Basic separation.

Flow between discs

30

1

2

1: G-Forces

2: Flow

Basic separation.

Flow between discs

2

1


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31Basic separation.

Flow between discs

32Basic separation.

Flow between discs


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33Basic separation.

Flow between discs

34

Oil inlet

Clean Oil outlet

Open Water outlet

Gravity Disc

Top disc

Interface

Sludge outlet

Basic separation.

Purifier bowl


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35

Oil inlet

Clean Oil outlet

Closed Water outlet

Clarifier Disc

Top disc

Sludge outlet

Basic separation.

Clarifier bowl

36

Factors affectinginterface position: 1

Density of oil decrease

Viscosity of oil decrease

Flow rate decrease

Temperature of oil

increase

- Interface movingtowards centre:

- Water blockingdisc stack

--Bad separationBad separation

efficiencyefficiency

Gravity disc too small

Basic separation.

Purifier


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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 movingtowards periphery

Factors affectinginterface position: 2

Gravity disc too big

Basic separation.

Purifier

38Basic separation.

Correct G-disc


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Separation Efficiency

Factors effecting separationEfficiency

40

Separator Filter

Particles < 4 m 65-85 5-10

Cat fines 60-90 ~ 5

Iron 40-60 ~ 5

Sodium 40-50 < 5

Average samples from 44 ships during normal operation

source Alfa Laval SMT/F 9402

Basic separation.



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41

Components in oils not effected by Separation

Density

Viscosity

CCAI

Flash point

Pour point

Micro Carbon Residue

Sulphur / Vanadium

Asphalthenes

Basic separation.


42

Water

Sodium

Aluminium

Silicone

Iron

Magnesium

Ash

Calcium

Cat-fines

Components in oils strongly effected by Separation

Basic separation.



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43Basic separation.

ISO 8217 . 2005

44Basic separation.


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45Basic separation.

Cat-fines distribution

46

Water in separator bowl in general:

In order to get the best possible separation result

- Water must never enter the disc stack !!!

Basic separation.



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47

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

Basic separation.


48

Correct gravity disc size

Clean Disc-stack

Maintain following feed conditions:

Constant oil properties = viscosity & density Constant FLOW - rate

Constant TEMPERATURE

Conventional separator: The purifier

Purifier optimum interface position: 2

Basic separation.



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49

HFO 380 temperature changedown from 98C to 95C

a change from 26 cSt up to 29 cSt

HFO 380 temperature changedown from 98C to 90C

a change from 26 cSt up to 35 cSt

Basic separation.


50

centrifugalsettlingvelocity(m/s)

continuousphaseViscosity(Kg/m, s )

centrifugalacceleration(m/s )2

heavy phasedensity(kg/m )

light phasedensity(kg/m )33

dropletsize(mm )

d

Basic separation.

Stokes LawApplied on centrifugal separation


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51

Density differenceParticle size

Separationefficiency

+

Viscosity

Basic separation.

Stokes LawAnd efficiency

52

Conventional separator system :

PURIFIER LIMITATIONS

PURIFIER followed by CLARIFIERThe Gravity Disc

Maximum Density 991 kg/m3

Manual Adjustment

Optimum Separation hard to achieve

Need of qualified attention for optimum result

Basic separation.



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NOTE :

All MAPX type separators and All MOPX / WHPX type

separators from before 1984/85 have a densitylimit around 985 kg / m at 15C

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

Basic separation.


54

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

Basic separation.



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55

Density limit =

991 Kg / m3 / 15C

Viscosity limit =

600 cSt/ 50C

Basic separation.

Limitations

56

Purifier Clarifier

From settling tank To clarifier To service tank

Basic separation.

Normal setup:Purifier to Clarifier


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ClarifierClarifier

From settling tank From settling tank

To service tankTo service tank

Reduced water removal!Disharge every 10 min!

Basic separation.

Emergency setup:High density oil

58

PurifierPurifier

From settling tank From settling tank

To service tankTo service tank

Reduced flow to consumption+ 10% over two separators

Basic separation.

Emergency setup:High cat fines in oil


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Know your oil!

Good instructions!Normal handling and in crices.

Eduicate the operators.

Advice:

Advice:

=

Documents

2 Basic NewVIIx