Coalescence Clarification

7/27/2019 Coalescence Clarification

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PALMOIL ENGINEERING BULLETINNO. 105 9

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* Malaysian Palm Oil Board, P. O. Box 10620, 50720Kuala Lumpur, Malaysia.

**Concept Engineering Sdn Bhd, No. 29 & 31, JalanIndustri USJ 1/4, 47600 Subang Jaya, Selangor,

Malaysia.E-mail: [email protected]

Coalescing Clarifier for Crude Palm OilClarification

Mohamad Sulong*; Ronnie C W Tan** and Krisada Chavananand**

W

FUNDAMENTALS

hen oil passes throughinterspaces between thecoalescence plate separatorplate, it imparts shear

forces to the small oil particles causingthem to agglomerate, thereby preventingthe formation of emulsion. As a result, thediameter of the oil particles become large

and separation eciency improves.

BASIS FOR SIZING AND SELECTION

For liquid-liquid coalescers, as with anyprocess equipment, successful sizingand selection is always a combination ofempirical observation/experience andanalytical modelling.

Of the three steps in coalescing, i.e.

droplet capture, combining of the collecteddroplets and gravity separation of theenlarged droplets the rst and the lastcan be modelled with good accuracyand repeatability. The modelling of themiddle and the actual coalescing step isa complex function of surface tension and

viscous eects, droplet momentum andthe dynamics of sizes of the droplets in thedispersion.

Two units were designed for a 60 t FFBhr-1 palm oil mill that used a conventionalvertical clarier tank as shown in Figures1 and 2. The material used for theconstruction of the coalescence separatorwas stainless steel SS 316 inserts, in a mild

steel casing with insulation thermal controland ow control equipment.

a

b


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PALMOILENGINEERINGBULLETINNO. 10510

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c d

e f

g h


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i j

Figure 1. Coalescing clarier (OILSEP) rst generation (Indonesia).

Figure 2. Coalescing clarier (OILSEP) at Vichitbhan oil mill second generation.

OILSEP DEVELOPMENT HISTORY

Years Events

2000

2002

2005 2008

2009

2009

2010

R&D with MPOB. Tested pilot unit at Krau Palm Oil Mill.

First units installed in a mill in Indonesia. First generation.

Three units in operation in Thailand.

Two units installed in Thailand for mill upgrading.

Discussion with interested parties: Univanich (Thailand),Papua New Guinea, Keck Seng (Malaysia), West Africa.

Planning to conduct testing on OILSEP without dilution.

k


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TYPICAL PERFORMANCE OF A SLUDGE SEPARATOR

Average ow rate: 11 800 kg hr-1 with 1.8 mm nozzle showing a strong correlation betweenoil content in feed and the oil content in the centrifuge heavy phase.

Figure 3. Oil in underow of coalesce clarier Vichitbahan oil mill.

Figure 4. Average material ow into centrifuge.

Figure 5. Infeed oil content conventional clarier.

k

g

hr-

1

16

14

12

10

8

6

4

2

0

(000)

Day

Day


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Figure 6. Centrifuge heavy phase oil content.

Figure 8. Oil in the underow of the coalescer clarier Vichitbahan oil mill.

COMPARISON OF OIL CONTENT IN THE UNDERFLOW OF THE OIL CLARIFIER

Average 6.82% Average 7.72%

Average 11.7%

Figure 7. Infeed oil content conventional clarier.

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Day

Day

Day


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Figure 9. Material balance of conventional crude palm oil clarier.

Figure 10. Material balance of coalescing clarier (OILSEP).

Figures 3 and 6 give the performance of the sludge separated, while Figures 7 and 10 give theperformance of the coalescing clarier (OILSEP).

PERFORMANCE COMPARISON

Tables 2 and 3 show the performance data of the oil separator (OILSEP) and the verticalclarier. OILSEP seems to outperform vertical clarier in almost all activities except in thecost which is more than double.

CONCLUSION

OILSEP utilises coalescing principle to enhance stokes gravity settling. This device also helpsto agglomerate small oil droplets formed during emulsication of crude oil slurry resulting in

better oil recovery in a short oil retention time. The process also complies with good millingpractices as all parts in contact with oil are made of stainless steel.

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Flow 36 000 kg hr-1

Oil 35% 12 600 kg hr-1

VM 58% 20 880 kg hr-1

NOS 7% 2520 kg hr-1

Flow 10 551 kg hr-1

Oil 98.9% 12 600 kg hr-1

VM 0.82% 85.0 kg hr-1

NOS 0.28% 29 kg hr-1

Flow 25449 kg hr-1

Oil 8.5% 12 600 kg hr-1

VM 81.7% 20 795 kg hr-1

NOS 9.8% 2491 kg hr-1

1946.7 kg hr-1 oil

216.3 kg hr-1 oil (3.6 kg t-1 FFB)

RT= 4-7 hr

Flow 11 985.6 kg hr-1

Oil 99.5% 10 985.6 kg hr-1

VM 0.47% 52.6 kg hr-1

NOS 0.03% 3.5 kg hr-1

Flow 24 958.3 kg hr-1

Oil 6.5% 1614.4 kg hr-1

VM 83.5% 20 827.4 kg hr-1

NOS 10% 2516.5 kg hr-1

Flow 36000 kg hr-1

Oil 35% 12 600 kg hr-1

VM 58% 20 880 kg hr-1

NOS 7% 2520 kg hr-1

1453 kg hr-1 oil

161.4 kg hr-1 oil (2.6 kg t-1 FFB)


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TABLE 1. COMPARISON BETWEEN OILSEP AND VERTICAL CLARIFIER

Description OILSEP Vertical clarifer Remarks

Oil recovery 12 438 kg hr-1 12 383.7 kg hr-1 54.9 kg hr-1

Oil content (underow) 5% - 7% 8.0% - 12% OILSEP very consistentFeeding and temperaturecontrol

Automatic90C 2C

Normally non-auto95C 98C

Low temperature minimisequality deterioration

Oil quality DOBI2.6 2.8

DOBI2.0 2.5

Consistent

Retention time 1 1.5 hr 4 7 hr Oil ow out within 45 min

Footprint for oil room 9 m x 6.5 m x 6 m (H) Much bigger Depends on tank size

Material of construction Housing 304 SSInserts 316 SS

304 SS lining Complies with CoP of millsLong life

Note: DOBI deterioration of bleachability index.CoP- code of practices.


Description OILSEP Vertical clarifer Remarks

Maintenance andcleaning

Very easy Time consuming High pressure water jetfor inserts cleaning

Puricationrequirement

Not required Yes Cleaner oil

Automation Fully auto, ow control,temperature control

Partial in someinstallation

Ensuring laminar ow forbetter oil coalescing

System performance Dynamic constantshearing of crude slurry

Static, no barrier forsolid movement

OILSEP is a dynamicsystem

Total surface area 150 m2 surface forshearing action

No shearing surface OILSEP surface area isequivalent to 200 t verticalclarier


Description OILSEP Vertical clarifer RemarksInvestment cost RM 1.4 million RM 600 00 RM 800 000

Return oninvestment

0.86 year new millcompared to verticalclarier1.52 years if installed inexisting oil room

- Overall oil recover = 54.9 kg hr-1or 1098 kg day-1 at 20 hr day-1 or1098 kg x 350 day yr-1 = 384.3 tyr-1 x RM 2400 t -1= RM 922 320

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Coalescence Clarification