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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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e f
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PALMOIL ENGINEERING BULLETINNO. 105 11
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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.
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PALMOILENGINEERINGBULLETINNO. 10512
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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
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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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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.
TABLE 2. COMPARISON BETWEEN OILSEP AND VERTICAL CLARIFIER
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
TABLE 3. COMPARISON BETWEEN OILSEP AND VERTICAL CLARIFIER
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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PALMOILENGINEERINGBULLETINNO. 10516