HEXANE ECONOMIZATION IN PALM KERNEL OIL PLANT: A STUDY AFTER PROCESS DESIGN IMPROVEMENT.
GLO BAL EN GIN EERS & TECH N O LO GISTS REVIEW
www.getview.org
HEXANE ECONOMIZATION IN PALM KERNEL OIL PLANT: A
STUDY AFTER PROCESS DESIGN IMPROVEMENT
SIVARAO1, KUMAR2, N., WIDODO3, W.S. and HAERYIP SIHOMBING4
1, 2
Department of Manufacturing Process
Department of Manufacturing Design
4
Department of Manufacturing Management
Faculty of Manufacturing Engineering
Universiti Teknikal Malaysia Melaka
Hang Tuah Jaya, 76100, Durian Tunggal, Melaka, MALAYSIA
1
sivarao@utem.edu.my
3
wswidodo@utem.edu.my
4
iphaery@utem.edu.my
3
A BSTRA CT
Hexane (C6H 14) is used as a solvent to extract oil from palm kernel to produce crude palm kernel oil
(CPKO) which is a common cooking ingredient. The main intention of this research work is to
reduce hexane loss during the extraction process of oil from palm kernel. This research project was
carried out in a leading vegetable factory in Malaysia. Although this plant managed to get high yield
(average 48.5 % ) compare with other similar conventional plants in Malaysia but the hexane loss is
very high, 8.5 litre/Metric Ton (l/MT) in average. To reduce the hexane loss, few modification jobs
were carried out; adding of new shell and tube condenser, sealing of leakages and developed a set of
standard operating procedures. Preliminary investigation after the improvement steps found that,
reduction of hexane loss showed a decrease of about 30 % from the average of 9.5 % litre/MT of palm
kernel 6.5 litre/MT of palm kernel after the improvement. This amounted of hexane savings of 3
litre/MT of palm kernel which is equivalent to about RM 727,660 for 8 months after the process
improvement taken into effect.
Keyw ords: Palm Kernel, Hexane, Extraction, Condenser.
1.0
I NTRODUCTION
Solvent extr action as a pr ocess utilizes solvents to extr act the r esidual oil fr om oil-bear ing seeds, cakes and
br ans (Dacer a et al., 2003). Vegetable oil has been the main sour ce of fat for human consumption. Most edible
oils and fats ar e soluble in liquid hydr ocar bons and hexane is the most commonly used hydr ocar bon fraction for
solvent extr action (Dacera et al., 2003). The solvent used in this pr ocess is not expanded, but is used over and
over again in the pr ocess of r ecycling and a lar ge volume of the solvent alw ays r emains in var ious stages of the
closed pr ocessing cycles.
Reducing pr oduction cost by r educing the hexane loss dur ing the pr ocess is the key point of this study.
The main aim of this r esearch w or k is to r educe hexane losses dur ing the oil extr acting pr ocess fr om palm ker nel
and to study how effectively hexane and oil in the for m of mischella can be separ ated in or der to r educe the
pr oduction cost w hile incr easing the pr ofit. Using Hexane to extr act oil is called solvent extr action or solvent
extr action plant. Solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, r esulting
in a solution that is soluble in cer tain volume of solvent at a specified temper atur e.
In solvent extr action plant, hexane is commonly used as a solvent to extr act the oil fr om the palm ker nel.
Hexane is a hydr ocar bon w ith the chemical for mula C6H14; that is, an alkane w ith six car bon atoms. Accor ding to
a r epor t by the Cor nucopia Institute, hexane is used to extr act oil fr om gr ains as w ell as pr otein fr om soy, to such
an extent that in 2007, gr ain pr ocessor s w er e r esponsible for mor e than tw o-thir ds of hexane emissions in the
United States (NVO Hexane Repor t, 2010). The r epor t also pointed out that the hexane can per sist in the final
food pr oduct cr eated; in a sample of pr ocessed soy, the oil contained 10 ppm, the meal 21 ppm and the gr its 14
ppm hexane. Using hexane to extr act oil is commonly used for oil-cake extr action (soya bean meal, gr oundnut
meal, r ice br an meal, cotton seed meal, sells seed, guar meal, copr a meal), oilseeds (soya bean, sunflow er seed,
gr oundnut, cotton, sal, niger , mustar d, castor ), vegetable oils (palm olefins, soya bean oil, r ap seed oil, sunflow er
seed oil), gr ains (w heat, cor n, r ice, sorghum, millets, bar ley) (Yuhazr i et al., 2012) and (House et al., 1981).
In Malaysia ther e is a leading vegetable oil plant using hexane to extr act oil fr om palm ker nel. This is the
only plant in Malaysia using hexane for dir ect extr action fr om palm ker nel flakes. This plant is divided into tw o
sections w her e the fir st section is pr epar ation plant and the second section is a solvent extr action plant. In the
-
G. L. O. B. A. L E. N. G. I . N. E. E. R. S. . & . . T . E. C. H. N. O. L. O. G. I. S. T . S R. E. V. I. E. W
7
Global Engineers & Technologist s Review , Vol.2 No.12
(2012)
pr epar ation plant, the palm ker nels w ill be hammer ed, cr ushed, flaked and conditioned by indir ect steam and
then, this flaked meal w ill be sent to the second section, solvent extr action plant w her e hexane w ill be pumped
and flushed to these flakes to extr act the oils. By using hexane about 48 % of cr ude palm ker nel oils and 52 % of
by-pr oduct, palm ker nel meal can be pr oduced.
By using this technology this plant is able to extr act mor e cr ude palm ker nel oils, yield an aver age 48 %
compar ed w ith conventional pr ess w hich w ould only be 44.5 % in average (Hai, 2002). Although this plant uses
hexane for solvent extr action fr om palm ker nel and gain higher yield compar ed w ith other conventional
methods, but they ar e facing pr oblem to r ecover hexane efficiently. Aver age hexane loss at the end of the day is
about 9.5 of hexane per ton of palm ker nel losses encounter ed. Basically this plant faces pr oblem w ith high
hexane losses dur ing the pr ocess of extr acting oils fr om palm ker nels. Complete pr ocess flow of pr epar ation and
extr action sections ar e show in the for m of flow char t in Figur e 1.
Figure 1 : Pr epar ation pl ant flow char t.
1.1
Preparation Plant
Pr epar ation plant is the place w her e daily pr oduction is set by key in the r equir ed flow r ate (MTs/ hour )
of palm ker nels in the w eigher machine. In this plant, after past the magnetic separator to separate metal
pieces, palm ker nels fr om silos will send to w eigher to pr oduce r equir ed flow rate per hour . After the
w eigher machine, the palm ker nels w ill enter to hammer mill wher e the palm ker nels w ill be hammer ed
to r educe the size and for fur ther r eduction the ker nels w ill past to the cracking r oller machine w her e the
ker nels w ill be cr ushed and br eak fur ther . To get high yield of cr ude palm ker nel oils (CPKO), the ker nels
must be soft and small size. So to get that r esult, the br oken ker nels w ill send to 1st oper ation flaker w her e
all these ker nels w ill be flaked to below 1.5 mm thickness and then all these mater ials w ill send to
conditioner w her e these flakes w ill be heated up w ith jacketed steam to get temper atur e about 70 °C.
After the conditioner these soft flakes w ill enter to 2nd oper ation flaker to get flakes thickness below 0.3 to
0.5 mm. Finally these flakes ar e r eady to extr act oil. All these pr ocess ar e online continuous pr ocess.
1.2
Extraction Plant
After the final pr ocess in pr epar ation plant, the flakes w ill be tr ansfer r ed to the ext r actor with 2
compar tments. In this extr actor , the fr esh hexane will be pumped into these flakes to extr act the oil. This
oil called miscella, means oil and hexane mixed together w her e miscella contains about 60 % of hexane.
To separ ate oil and hexane, this miscella will go thr ough another pr ocess in distillation plant. After the
oils w er e extr acted fr om the flakes, the by-pr oduct, palm ker nels meals fr om the 2nd compar tment w ill be
pr oduced. This by-pr oduct, palm ker nel meals contains ar ound 40 % of hexane. To separ ate meals and
hexane, these by pr oducts w ill be sent to another plant, meal de-solventizing. Pr ocess flow of the
extr action plant is show n in Figur e 2.
Distillation is the pr ocess to separ ate the miscella into cr ude palm ker nel oil and hexane. In this
plant the mischella will be heated up in thr ee differ ent stages and temper atur e till captur e all the hot
hexane vapor and this hot vapor w ill be vacuumed to thr ee differ ent condenser s to cool it and r egain the
hexane in liquid for m and w ill be r e-used. In this meal de-solventizing plant, the by-pr oduct w ill be heated
© 2012 GETview Limit ed. All right s reserved
8
Global Engineers & Technologist s Review , Vol.2 No.12
(2012)
up by going thr ough a super heater and by using vacuum about –0.5bar , the hot hexane vapor will be
sucked into condenser w her e, heat tr ansfer will take place to conver t the hexane into vapor to liquid
for m. This liquid hexane w ill be stor ed in w or king tank and w ill be r ecycled to the extr actor .
Whatever hexane missed to collect in distillation and meal de-solventizing pr ocess, will be sent to
absor ption plant w her e, in this plant absor ption oil will be used to tr ap w hatever missing hexane. The
hexane, w hich dilute w ith abr uption oil, w ill send to absor ption column and follow ed by heat exchanger
to heat up the hexane to separ ate it fr om absor ption oil and then w ill past to 2 nd heat exchanger to br ing
back the hexane to liquid for m and finally all the collected hexane w ill be tr ansfer r ed to the hexane
w or king tank. After the hexane r emoved thr ough the above pr ocess, the oil called cr ude palm ker nel oil,
CPKO and the by-pr oduct is palm ker nel meal. By this ext r action pr ocess ar ound 48 % Cr ude palm ker nel
oils and 52 % of by-pr oduct, palm ker nel meals is pr oduced. The CPKO w ill be t r ansfer r ed to main stor age
tank to sell out or fur ther pr ocess in the r efiner y plant. The palm ker nel meal w ill send to palletizing plant
to pr oduce palm ker nel pallets and palm ker nels meal.
Figure 2 : Extr action plant flow char t.
2.0
M ATERIALS AND M ETHODS
2.1
Pre-assessment
Pr e-assessment audit w er e car r ied out on high hexane loss follow ed an assessment to focus the major
pr oblems and implementation to r educe the hexane loss and finally monitor ing and evaluation of the final
r esult. The pr e-assessment audit was conducted in May, 2011. Pr e-assessment audit w as conducted to
focus ar ea of high hexane loss based on fish bone diagr am as show n in Figur e 3. Input details w er e
collected thr ough cur r ent r esult, par ameter s, inter view s, questionnair es and br ain stor ming sections.
Figure 3 : Fishbone analysi s.
© 2012 GETview Limit ed. All right s reserved
9
Global Engineers & Technologist s Review , Vol.2 No.12
(2012)
Based on the pr e-assessment findings, the audit w as focused on:
(i)
Excess loss
Excess loss is the amount of additional loss thr ough:
(a)
(b)
(c)
(d)
(e)
(f)
oil fr om the final oil str ipper.
air fr om the meal dr yer cooler.
meal fr om meal dr yer cooler.
air fr om the miner al oil system.
w ater fr om w aste water evapor ator.
inconsistent oper ation.
The excess loss due to inconsistent oper ation occur s dur ing the per iod star ting w hen the
input conditions change and ending w hen the input conditions change back to nor mal, or dur ing
the per iod star ting w hen the input condition change and ending w hen steady state is achieved after
the oper ating par ameter s have changed.
(ii)
Fugitive loss
Fugitive loss is the amount of solvent loss fr om the pr ocess equipment thr ough flanges, door s,
packing glands, pump seals, valves stems, sight glasses, etc. This loss occur s w hen the pr essur e
inside the vessel is higher than atmospher ic pr essur e, causing solvent vapour inside the vessel to
leak out thr ough any or ifice.
(iii)
Pur ging loss
Pur ging loss is amount of solvent loss fr om pr ocess equipment r esulting fr om fr eeing the pr ocess
equipment of solvent vapour for inspection or maintenance. This loss occur s as a r esult of opening
up the pr ocess equipment and as a r esult of using pur ge fans to pull air thr ough the pr ocess
equipment. Dur ing nor mal oper ation, pur ging loss does not exist. Pur ging loss only exists w hen the
plant is shutdow n. Thus, the solvent loss as a r esult of pur ging can not be quantified in ter ms of
litter s of solvent loss per ton of palm ker nel pr ocessed on a dir ect basis, as w ith other categories of
solvent loss.
2.2
Assessment
Based on findings in the fish bone diagram, the assessment audit w as conducted in July 2011. The
assessment w as focused on excess loss, fugitive loss and pur ging loss. The pur pose of the assessment w as
to collect detail infor mation on high hexane loss due to excess loss, fugitive loss and pur ging loss.
2.2.1 Assessment phase 1: excess loss
Excess loss is the only ar ea able to do analyse the quantity of hexane contains in cr ude palm ker nel
oil, palm ker nel meal, vent gases fr om absor ption and w ater fr om waste w ater system. Hexane
contains in cr ude palm ker nel oil measur ed by flash point temper atur e meanw hile hexane contain
in palm ker nel meal and waste water measur ed by mg/ kg or ppm and hexane contain in vent gases
fr om absor ption measur ed by kg/ or ppm. Accor ding to Solvent Extr actor s Association Handbook
of India 9 th r evised edition 2009, the allowable r ange for for flash point is min 100 °C, hexane
contain in palm ker nel meal is 170 ppm, hexane contain in vent gases is 50 mg/ and hexane contain
in waste water is 10 ppm. Detail audit of analyzing the hexane contains w er e car r ied on Januar y till
May 2011 and the aver age for these 5 months ar e as per i n Table 1.
Table 1 : Detail audit data.
Palm Ker nel thr u put
(MT)
CPKO-Flash Point
(°C)
Hexane i n Pal m Ker nel Meal
(ppm)
Vent gases fr om absor pt ion
(mg/ l tr )
Wat er
(ppm)
Januar y
2011
Febr uar y
2011
Mar ch
2011
Apr il
2011
May
2011
Acceptable
12,250
11,510
12,505
12,500
12,498
-
120
120
120
120
120
Min 100
210
300
250
225
220
170
600
500
550
580
570
50
8
6
10
8
8
10
© 2012 GETview Limit ed. All right s reserved
10
Global Engineers & Technologist s Review , Vol.2 No.12
(2012)
Base on data fr om Table 1, four independent plots w er e developed to have a clear pictur e of
the impr ovement in better hexane r ecover y.
(a)
(b)
Figure 4 : (a) compar i son of actual & allow abl e w it h PK thr u put, (b) compar ison of hexane contain in palm ker nel meal w it h PK thr u put.
Fr om Figur e 4(a), 4(b), 5(a) and 5(b), it was found that ther e is high hexane loss in vent air
fr om absor ption compar e with other hexane losses in CPKO, palm ker nel meal and waste water .
Decision w as made to focus on hexane loss in vent air and to dr aft an action plan and impr ovement.
Detail studies and audits w er e car r ied out in distillation section as show n in Figur e 6.
(a)
(b)
Figure 5 : Compar ison of hexane cont ai n i n (a) vent air w ith PK thr u put , (b) w aste w ater w ith PK thr u put.
The vent air blows thr ough absor ption section but the unr ecover ed hexane vapor comes
mainly fr om distillation section, w hile small amount from extr actor . To save 50 % steam of the
distillation is achieved using hot De-solventizer vapor s in a unique falling film economizer . This
r educes the steam consumption and the load on the final condenser . This is follow ed by a steam
heated r ising film evaporator s and str ipping column oper ating under vacuum.
Figure 6 : Dist illation section befor e modification.
The vapor s fr om falling film economizer , r ising film evapor ator s 1 and 2 and fr om str ipper
column w ill be sucked into condenser s to condense hexane vapor to liquid for m. The hexane vapor
that is not condensed in the last condenser is typically passed thr ough a miner al oil absor ption
system. The hexane liquid w ill be tr ansfer r ed into special water separ ator to r emove the w aste
w ater . After maximum r ecover y by condensation fur ther hexane content in the exhaust air can be
fur ther r educed only by an absor ption by intimate contact with chilled miner al oil in specially
designed packed column. Ther eafter the air is exhausted to the atmospher e with the maximum
hexane content and the absor ber oil is str ipped w ith dir ect str eam to r emove the t r aces of hexane
and send for r e-cir culation to cold absor ber .
The special absor ber unit is a packed column. The air aspir ated w ith the feedstock into the
plant has to be evacuated. This air is a car r ier of hexane at its satur ation vapor pr essur e. So the
© 2012 GETview Limit ed. All right s reserved
11
Global Engineers & Technologist s Review , Vol.2 No.12
(2012)
exhaust air is cooled fir st in chilled w ater vent condenser to a temper atur e ar ound 20 °C for
maximum r ecover y by condensation. To r educe the hexane content in vent air , ther e ar e tw o
options consider ed: upgr ade complete absor ption section and add 1 mor e condenser to incr ease
the condensation capacity. Since the cost is high to upgr ade the complete absor ption system,
r ecommendation given to management to add 1 mor e condenser s in the distillation plant. Table 2
show s the existing and the r ecommendation.
Table 2: Existi ng and pr oposed di still ation i nst allation.
Wat er Temper atur e
(°C)
In
Out
C1
450
200
32
38
C2
450
200
32
38
C3
450
200
32
38
*Recommendation: Add new condenser of 450m 2
Condenser
Ar ea
(m 2 )
Wat er Flow
Rate (m 3 )
Hexane Vapour
Temper atur e (°C)
In
Out
120
44
90
40
90
40
2.2.2 Assessment phase 2: fugitive loss
Decisions taken to car r y out pr essur e test all equipment and piping w ith pr essur ized w ater to
ensur e that the syst em is fr ee of leaks pr ior to star t oper ation.
2.2.3 Assessment phase 3: purging loss
Pur ging loss only exist once the plant is star ting back after the shutdow n. Case study w as car r ied
for the year 2010 of high hexane losses dur ing the plant star t back after mor e than 1 day shutdow n
as show n in Figur e 7. The actions that can be taken to minimize the pur ging loss ar e:
(i)
(ii)
(iii)
Impr ove equipment r eliability thr ough design impr ovement and tr ough pr eventive
maintenance pr ocesses. This w ill r educe the fr equency for w hich maintenance and
inspection ar e r equir ed, thus r educing the fr equency of vapor fr eeing and its r elated pur ging
solvent loss.
Allow the nor mal vapor r ecover y system t o r un as long as possible prior opening up the
pr ocess equipment. This will r ecover the major ity of the solvent pr ior to vapor fr eeing, thus
r educing pur ging loss.
Dischar ge the pur ge fan thr ough a condenser to r ecover as much as the solvent vapor as
possible, thus r educing pur ging solvent loss.
Decision w as taken to car r y out action plant no 2 due to able t o car r y out the action
immediately w ithout any major cost.
Figure 7 : Hexane loss aft er pl ant st ar ti ng back fr om shut dow n.
2.3
I mplementation
Once the action plans w er e selected for excess, fugitive and pur ging loss, decision taken to implement the
action plans in stages, 1st excess loss follow ed by fugitive loss and finally pur ging loss.
2.3.1 Excess loss
On 23 December 2011, added 1 mor e condenser , 450 m 2 to incr ease the cooling capacity fr om
1350m 2 to 1800m 2 (r efer to Figur e 8). This mainly to condense the vapor fr om economizer s,
evapor ator s and str ipper and r educe the excess load in absor ption section.
© 2012 GETview Limit ed. All right s reserved
12
Global Engineers & Technologist s Review , Vol.2 No.12
(2012)
2.3.2 Fugitive Loss
On 02 June 2012, the complete solvent extr action plant w as shutdow n for annual maintenance
w or ks. The action taken to pr essur e tests all the equipment including economizer s, evapor ator s,
str ipper , vapor s lines and vessels. The pr essur e test car r ied out by using w ater and found the w ater
leaking fr om economizer top manhole, evapor ator s tr ansfer line flange, sever al piping flange and 1
elbow cr acked. Gaskets w er e changed to all the leaking ar ea and r eplaced new elbow .
2.3.3 Purging Loss
A shutdow n pr ocedur es w as planned and a case study w as car r ied out fr om June to August 2012,
decision taken that vacuum pump, steam and cooling tow er need to be oper ated continuously for 3
hour s befor e the plant completely shut dow n. This due to allow the nor mal vapor r ecover y system
and r ecover the major ity hexane vapor to be condensed.
Figure 8 : Di stillation section after modification.
3.0
RESULTS AND DISCUSSION
The r esults after the impr ovement w er e r ecor ded in t hr ee differ ent stages. The findings and discussion ar e
focused on hexane loss in excess loss, pur ging loss and fugitive loss.
3.1
Excess Loss
After installed new condenser to incr ease the cooling capacity fr om 1350 m 2 to 1800 m 2, r esults ar e
monitor ed for hexane content in ventilated air fr om Januar y 2012 to May 2012. Based on the r esults, a
gr aph w as plotted as per Figur e 9(a). This graph show s hexane contains in vent r educed fr om average
560 mg/ litr e taken in Januar y-May 2011 to aver age 132 mg/ litr e. Detail analysis of hexane loss also
car r ied in the same per iod. Figur e 9(b) is the r esults and found after the installed new condenser , the
hexane loss r educed fr om aver age 9.5 litr e/ MT to 7.5 litr e/ MT.
Figure 9 : (a) Monitor i ng hexane i n vent air , (b) hexane excess loss befor e and after modification.
3.2
Fugitive Loss
After r ectified all the leakages especially fr om economizer , evapor ator s’ flanges and elbow s and fittings,
detail analysis w as car r ied for 3 months. A gr aph w as plotted base on the r esults. Figur e 10(a) clear ly
show s the impr ovement and saving about 1 litr e/ MT after stop the leakages.
© 2012 GETview Limit ed. All right s reserved
13
Global Engineers & Technologist s Review , Vol.2 No.12
(2012)
Figure 10: Hexane befor e and aft er modificat ion, (a) fugitive loss, (b) Pur gi ng loss.
3.3 Purging Loss
Although the hexane loss due to pur ging cannot be quantified in ter ms of litr e of solvent loss per ton of
palm ker nel pr ocessed on a dir ect basis but it’s ver y impor tant to keep the hexane loss as low as possible
dur ing the plant star t up after shutdow n. Follow ing the specific shutdow n and star t-up pr ocedur es
complying detailed checklists, the r esults have been impr oved as show n in Figur e 10(b).
4.0
CONCLUSION
Hexane loss has always been the significant r eason incurr ing cost for oper ating of an extr action plant. Per haps,
in the past, ther e w er e times w hen additional solvent usage was accepted as par t of having low er r esidual oils in
the meal and mill feed or even low er ener gy costs in steam pr oduction, but discar ded by r ecent food and safety
r egulations. How ever excessive expenditur e for additional solvent r ecover y or pollution contr ol equipment
w ould not be necessar y if a plant is pr oper ly oper ated and maintained. Table 3 clear ly show s the total saving of
RM 727, 660 fr om Januar y 2012 to August 2012 after the impr ovements w e implemented.
Table 3: Total saving of hexane
PK thr oughput ( mt)
Januar y
2012
Febr uar y
2012
Mar ch
2012
Apr il
2012
May
2012
June
2012
July
2012
August
2012
7,943
13,652
12,723
12,557
15,086
14,066
14,754
12,840
Hexane Loss (/ mt)
7.3
7.8
7.4
7.5
7.5
6.6
6.5
6.5
Hexane Pr ice (RM/ s)
2.89
2.82
2.82
2.43
3.17
3.22
3.05
2.94
Aver age Hexane loss
in year 2011
9.5
9.5
9.5
9.5
9.5
9.5
9.5
9.5
50,494
65,536
75,450
61,020
95,704
131,261
134,871
113,324
Saving (RM)
ACKNOWLEDMENTS
Author s w ould like to thank Faculty of Manufactur ing Engineer ing and Univer siti Teknikal Malaysia Melaka for
suppor ting this r esear ch Special thanks to Ministr y of Higher Education (MOHE) for awar ding r esear ch gr ants
(GLuar / 2012/ FKP(1)/ G00010) and (PRGS/ 2012/ TK01/ FKP/ 02/ 1/ T0003) w hich ver y much helped in
completing the study w ithout much hur dles.
REFERENCES
[ 1] Dacer a, D., Jenvanitpanjakul, P., Nitisoravut, S. and Babel, S. (2003): Hexan Reduction in a Thai Rice Bran Oil
factor y: A Cleaner Technology Appr oach. Thammasat Int. Jour nal of Science and Technology, Vol.8, No.4,
pp.6-16.
[ 2] NVO Hexane Repor t (2010): Soy Pr otein and Chemical Solvents in Nutr ition Bar s and Meat Alter natives,
Cor nucopia Institute.
[ 3] Hai, T.C. (2002): The Palm Oil Industr y in Malaysia: Fr om Seed to Fr ying Pan, Plantation Agr icultur e - WWF
Malaysia.
[ 4] House, R.J.R., Har combe, A.O. and Guinness R.G. (1981): Hexane Losses in Solvent Extr acted Soya Meal:
Measur ement by Gas Chr omatography and Br ief Evaluation. Jour nal of the Amer ican Oil Chemist’ Society,
pp.626-629.
[ 5] Yuhazr i, M.Y., Haer yip Sihambing, Umar Nirmal, Saijod Lau and Phongsakor n Pr ak Tom. (2012): Solid Fuel
fr om Empty Fr uit Bunch Fiber and Waste Paper s part1: Heat Released fr om Combustion Test. Global
Engineer s and Technologists Review . Vol.2, No.1, pp.7-13.
© 2012 GETview Limit ed. All right s reserved
14
www.getview.org
HEXANE ECONOMIZATION IN PALM KERNEL OIL PLANT: A
STUDY AFTER PROCESS DESIGN IMPROVEMENT
SIVARAO1, KUMAR2, N., WIDODO3, W.S. and HAERYIP SIHOMBING4
1, 2
Department of Manufacturing Process
Department of Manufacturing Design
4
Department of Manufacturing Management
Faculty of Manufacturing Engineering
Universiti Teknikal Malaysia Melaka
Hang Tuah Jaya, 76100, Durian Tunggal, Melaka, MALAYSIA
1
sivarao@utem.edu.my
3
wswidodo@utem.edu.my
4
iphaery@utem.edu.my
3
A BSTRA CT
Hexane (C6H 14) is used as a solvent to extract oil from palm kernel to produce crude palm kernel oil
(CPKO) which is a common cooking ingredient. The main intention of this research work is to
reduce hexane loss during the extraction process of oil from palm kernel. This research project was
carried out in a leading vegetable factory in Malaysia. Although this plant managed to get high yield
(average 48.5 % ) compare with other similar conventional plants in Malaysia but the hexane loss is
very high, 8.5 litre/Metric Ton (l/MT) in average. To reduce the hexane loss, few modification jobs
were carried out; adding of new shell and tube condenser, sealing of leakages and developed a set of
standard operating procedures. Preliminary investigation after the improvement steps found that,
reduction of hexane loss showed a decrease of about 30 % from the average of 9.5 % litre/MT of palm
kernel 6.5 litre/MT of palm kernel after the improvement. This amounted of hexane savings of 3
litre/MT of palm kernel which is equivalent to about RM 727,660 for 8 months after the process
improvement taken into effect.
Keyw ords: Palm Kernel, Hexane, Extraction, Condenser.
1.0
I NTRODUCTION
Solvent extr action as a pr ocess utilizes solvents to extr act the r esidual oil fr om oil-bear ing seeds, cakes and
br ans (Dacer a et al., 2003). Vegetable oil has been the main sour ce of fat for human consumption. Most edible
oils and fats ar e soluble in liquid hydr ocar bons and hexane is the most commonly used hydr ocar bon fraction for
solvent extr action (Dacera et al., 2003). The solvent used in this pr ocess is not expanded, but is used over and
over again in the pr ocess of r ecycling and a lar ge volume of the solvent alw ays r emains in var ious stages of the
closed pr ocessing cycles.
Reducing pr oduction cost by r educing the hexane loss dur ing the pr ocess is the key point of this study.
The main aim of this r esearch w or k is to r educe hexane losses dur ing the oil extr acting pr ocess fr om palm ker nel
and to study how effectively hexane and oil in the for m of mischella can be separ ated in or der to r educe the
pr oduction cost w hile incr easing the pr ofit. Using Hexane to extr act oil is called solvent extr action or solvent
extr action plant. Solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, r esulting
in a solution that is soluble in cer tain volume of solvent at a specified temper atur e.
In solvent extr action plant, hexane is commonly used as a solvent to extr act the oil fr om the palm ker nel.
Hexane is a hydr ocar bon w ith the chemical for mula C6H14; that is, an alkane w ith six car bon atoms. Accor ding to
a r epor t by the Cor nucopia Institute, hexane is used to extr act oil fr om gr ains as w ell as pr otein fr om soy, to such
an extent that in 2007, gr ain pr ocessor s w er e r esponsible for mor e than tw o-thir ds of hexane emissions in the
United States (NVO Hexane Repor t, 2010). The r epor t also pointed out that the hexane can per sist in the final
food pr oduct cr eated; in a sample of pr ocessed soy, the oil contained 10 ppm, the meal 21 ppm and the gr its 14
ppm hexane. Using hexane to extr act oil is commonly used for oil-cake extr action (soya bean meal, gr oundnut
meal, r ice br an meal, cotton seed meal, sells seed, guar meal, copr a meal), oilseeds (soya bean, sunflow er seed,
gr oundnut, cotton, sal, niger , mustar d, castor ), vegetable oils (palm olefins, soya bean oil, r ap seed oil, sunflow er
seed oil), gr ains (w heat, cor n, r ice, sorghum, millets, bar ley) (Yuhazr i et al., 2012) and (House et al., 1981).
In Malaysia ther e is a leading vegetable oil plant using hexane to extr act oil fr om palm ker nel. This is the
only plant in Malaysia using hexane for dir ect extr action fr om palm ker nel flakes. This plant is divided into tw o
sections w her e the fir st section is pr epar ation plant and the second section is a solvent extr action plant. In the
-
G. L. O. B. A. L E. N. G. I . N. E. E. R. S. . & . . T . E. C. H. N. O. L. O. G. I. S. T . S R. E. V. I. E. W
7
Global Engineers & Technologist s Review , Vol.2 No.12
(2012)
pr epar ation plant, the palm ker nels w ill be hammer ed, cr ushed, flaked and conditioned by indir ect steam and
then, this flaked meal w ill be sent to the second section, solvent extr action plant w her e hexane w ill be pumped
and flushed to these flakes to extr act the oils. By using hexane about 48 % of cr ude palm ker nel oils and 52 % of
by-pr oduct, palm ker nel meal can be pr oduced.
By using this technology this plant is able to extr act mor e cr ude palm ker nel oils, yield an aver age 48 %
compar ed w ith conventional pr ess w hich w ould only be 44.5 % in average (Hai, 2002). Although this plant uses
hexane for solvent extr action fr om palm ker nel and gain higher yield compar ed w ith other conventional
methods, but they ar e facing pr oblem to r ecover hexane efficiently. Aver age hexane loss at the end of the day is
about 9.5 of hexane per ton of palm ker nel losses encounter ed. Basically this plant faces pr oblem w ith high
hexane losses dur ing the pr ocess of extr acting oils fr om palm ker nels. Complete pr ocess flow of pr epar ation and
extr action sections ar e show in the for m of flow char t in Figur e 1.
Figure 1 : Pr epar ation pl ant flow char t.
1.1
Preparation Plant
Pr epar ation plant is the place w her e daily pr oduction is set by key in the r equir ed flow r ate (MTs/ hour )
of palm ker nels in the w eigher machine. In this plant, after past the magnetic separator to separate metal
pieces, palm ker nels fr om silos will send to w eigher to pr oduce r equir ed flow rate per hour . After the
w eigher machine, the palm ker nels w ill enter to hammer mill wher e the palm ker nels w ill be hammer ed
to r educe the size and for fur ther r eduction the ker nels w ill past to the cracking r oller machine w her e the
ker nels w ill be cr ushed and br eak fur ther . To get high yield of cr ude palm ker nel oils (CPKO), the ker nels
must be soft and small size. So to get that r esult, the br oken ker nels w ill send to 1st oper ation flaker w her e
all these ker nels w ill be flaked to below 1.5 mm thickness and then all these mater ials w ill send to
conditioner w her e these flakes w ill be heated up w ith jacketed steam to get temper atur e about 70 °C.
After the conditioner these soft flakes w ill enter to 2nd oper ation flaker to get flakes thickness below 0.3 to
0.5 mm. Finally these flakes ar e r eady to extr act oil. All these pr ocess ar e online continuous pr ocess.
1.2
Extraction Plant
After the final pr ocess in pr epar ation plant, the flakes w ill be tr ansfer r ed to the ext r actor with 2
compar tments. In this extr actor , the fr esh hexane will be pumped into these flakes to extr act the oil. This
oil called miscella, means oil and hexane mixed together w her e miscella contains about 60 % of hexane.
To separ ate oil and hexane, this miscella will go thr ough another pr ocess in distillation plant. After the
oils w er e extr acted fr om the flakes, the by-pr oduct, palm ker nels meals fr om the 2nd compar tment w ill be
pr oduced. This by-pr oduct, palm ker nel meals contains ar ound 40 % of hexane. To separ ate meals and
hexane, these by pr oducts w ill be sent to another plant, meal de-solventizing. Pr ocess flow of the
extr action plant is show n in Figur e 2.
Distillation is the pr ocess to separ ate the miscella into cr ude palm ker nel oil and hexane. In this
plant the mischella will be heated up in thr ee differ ent stages and temper atur e till captur e all the hot
hexane vapor and this hot vapor w ill be vacuumed to thr ee differ ent condenser s to cool it and r egain the
hexane in liquid for m and w ill be r e-used. In this meal de-solventizing plant, the by-pr oduct w ill be heated
© 2012 GETview Limit ed. All right s reserved
8
Global Engineers & Technologist s Review , Vol.2 No.12
(2012)
up by going thr ough a super heater and by using vacuum about –0.5bar , the hot hexane vapor will be
sucked into condenser w her e, heat tr ansfer will take place to conver t the hexane into vapor to liquid
for m. This liquid hexane w ill be stor ed in w or king tank and w ill be r ecycled to the extr actor .
Whatever hexane missed to collect in distillation and meal de-solventizing pr ocess, will be sent to
absor ption plant w her e, in this plant absor ption oil will be used to tr ap w hatever missing hexane. The
hexane, w hich dilute w ith abr uption oil, w ill send to absor ption column and follow ed by heat exchanger
to heat up the hexane to separ ate it fr om absor ption oil and then w ill past to 2 nd heat exchanger to br ing
back the hexane to liquid for m and finally all the collected hexane w ill be tr ansfer r ed to the hexane
w or king tank. After the hexane r emoved thr ough the above pr ocess, the oil called cr ude palm ker nel oil,
CPKO and the by-pr oduct is palm ker nel meal. By this ext r action pr ocess ar ound 48 % Cr ude palm ker nel
oils and 52 % of by-pr oduct, palm ker nel meals is pr oduced. The CPKO w ill be t r ansfer r ed to main stor age
tank to sell out or fur ther pr ocess in the r efiner y plant. The palm ker nel meal w ill send to palletizing plant
to pr oduce palm ker nel pallets and palm ker nels meal.
Figure 2 : Extr action plant flow char t.
2.0
M ATERIALS AND M ETHODS
2.1
Pre-assessment
Pr e-assessment audit w er e car r ied out on high hexane loss follow ed an assessment to focus the major
pr oblems and implementation to r educe the hexane loss and finally monitor ing and evaluation of the final
r esult. The pr e-assessment audit was conducted in May, 2011. Pr e-assessment audit w as conducted to
focus ar ea of high hexane loss based on fish bone diagr am as show n in Figur e 3. Input details w er e
collected thr ough cur r ent r esult, par ameter s, inter view s, questionnair es and br ain stor ming sections.
Figure 3 : Fishbone analysi s.
© 2012 GETview Limit ed. All right s reserved
9
Global Engineers & Technologist s Review , Vol.2 No.12
(2012)
Based on the pr e-assessment findings, the audit w as focused on:
(i)
Excess loss
Excess loss is the amount of additional loss thr ough:
(a)
(b)
(c)
(d)
(e)
(f)
oil fr om the final oil str ipper.
air fr om the meal dr yer cooler.
meal fr om meal dr yer cooler.
air fr om the miner al oil system.
w ater fr om w aste water evapor ator.
inconsistent oper ation.
The excess loss due to inconsistent oper ation occur s dur ing the per iod star ting w hen the
input conditions change and ending w hen the input conditions change back to nor mal, or dur ing
the per iod star ting w hen the input condition change and ending w hen steady state is achieved after
the oper ating par ameter s have changed.
(ii)
Fugitive loss
Fugitive loss is the amount of solvent loss fr om the pr ocess equipment thr ough flanges, door s,
packing glands, pump seals, valves stems, sight glasses, etc. This loss occur s w hen the pr essur e
inside the vessel is higher than atmospher ic pr essur e, causing solvent vapour inside the vessel to
leak out thr ough any or ifice.
(iii)
Pur ging loss
Pur ging loss is amount of solvent loss fr om pr ocess equipment r esulting fr om fr eeing the pr ocess
equipment of solvent vapour for inspection or maintenance. This loss occur s as a r esult of opening
up the pr ocess equipment and as a r esult of using pur ge fans to pull air thr ough the pr ocess
equipment. Dur ing nor mal oper ation, pur ging loss does not exist. Pur ging loss only exists w hen the
plant is shutdow n. Thus, the solvent loss as a r esult of pur ging can not be quantified in ter ms of
litter s of solvent loss per ton of palm ker nel pr ocessed on a dir ect basis, as w ith other categories of
solvent loss.
2.2
Assessment
Based on findings in the fish bone diagram, the assessment audit w as conducted in July 2011. The
assessment w as focused on excess loss, fugitive loss and pur ging loss. The pur pose of the assessment w as
to collect detail infor mation on high hexane loss due to excess loss, fugitive loss and pur ging loss.
2.2.1 Assessment phase 1: excess loss
Excess loss is the only ar ea able to do analyse the quantity of hexane contains in cr ude palm ker nel
oil, palm ker nel meal, vent gases fr om absor ption and w ater fr om waste w ater system. Hexane
contains in cr ude palm ker nel oil measur ed by flash point temper atur e meanw hile hexane contain
in palm ker nel meal and waste water measur ed by mg/ kg or ppm and hexane contain in vent gases
fr om absor ption measur ed by kg/ or ppm. Accor ding to Solvent Extr actor s Association Handbook
of India 9 th r evised edition 2009, the allowable r ange for for flash point is min 100 °C, hexane
contain in palm ker nel meal is 170 ppm, hexane contain in vent gases is 50 mg/ and hexane contain
in waste water is 10 ppm. Detail audit of analyzing the hexane contains w er e car r ied on Januar y till
May 2011 and the aver age for these 5 months ar e as per i n Table 1.
Table 1 : Detail audit data.
Palm Ker nel thr u put
(MT)
CPKO-Flash Point
(°C)
Hexane i n Pal m Ker nel Meal
(ppm)
Vent gases fr om absor pt ion
(mg/ l tr )
Wat er
(ppm)
Januar y
2011
Febr uar y
2011
Mar ch
2011
Apr il
2011
May
2011
Acceptable
12,250
11,510
12,505
12,500
12,498
-
120
120
120
120
120
Min 100
210
300
250
225
220
170
600
500
550
580
570
50
8
6
10
8
8
10
© 2012 GETview Limit ed. All right s reserved
10
Global Engineers & Technologist s Review , Vol.2 No.12
(2012)
Base on data fr om Table 1, four independent plots w er e developed to have a clear pictur e of
the impr ovement in better hexane r ecover y.
(a)
(b)
Figure 4 : (a) compar i son of actual & allow abl e w it h PK thr u put, (b) compar ison of hexane contain in palm ker nel meal w it h PK thr u put.
Fr om Figur e 4(a), 4(b), 5(a) and 5(b), it was found that ther e is high hexane loss in vent air
fr om absor ption compar e with other hexane losses in CPKO, palm ker nel meal and waste water .
Decision w as made to focus on hexane loss in vent air and to dr aft an action plan and impr ovement.
Detail studies and audits w er e car r ied out in distillation section as show n in Figur e 6.
(a)
(b)
Figure 5 : Compar ison of hexane cont ai n i n (a) vent air w ith PK thr u put , (b) w aste w ater w ith PK thr u put.
The vent air blows thr ough absor ption section but the unr ecover ed hexane vapor comes
mainly fr om distillation section, w hile small amount from extr actor . To save 50 % steam of the
distillation is achieved using hot De-solventizer vapor s in a unique falling film economizer . This
r educes the steam consumption and the load on the final condenser . This is follow ed by a steam
heated r ising film evaporator s and str ipping column oper ating under vacuum.
Figure 6 : Dist illation section befor e modification.
The vapor s fr om falling film economizer , r ising film evapor ator s 1 and 2 and fr om str ipper
column w ill be sucked into condenser s to condense hexane vapor to liquid for m. The hexane vapor
that is not condensed in the last condenser is typically passed thr ough a miner al oil absor ption
system. The hexane liquid w ill be tr ansfer r ed into special water separ ator to r emove the w aste
w ater . After maximum r ecover y by condensation fur ther hexane content in the exhaust air can be
fur ther r educed only by an absor ption by intimate contact with chilled miner al oil in specially
designed packed column. Ther eafter the air is exhausted to the atmospher e with the maximum
hexane content and the absor ber oil is str ipped w ith dir ect str eam to r emove the t r aces of hexane
and send for r e-cir culation to cold absor ber .
The special absor ber unit is a packed column. The air aspir ated w ith the feedstock into the
plant has to be evacuated. This air is a car r ier of hexane at its satur ation vapor pr essur e. So the
© 2012 GETview Limit ed. All right s reserved
11
Global Engineers & Technologist s Review , Vol.2 No.12
(2012)
exhaust air is cooled fir st in chilled w ater vent condenser to a temper atur e ar ound 20 °C for
maximum r ecover y by condensation. To r educe the hexane content in vent air , ther e ar e tw o
options consider ed: upgr ade complete absor ption section and add 1 mor e condenser to incr ease
the condensation capacity. Since the cost is high to upgr ade the complete absor ption system,
r ecommendation given to management to add 1 mor e condenser s in the distillation plant. Table 2
show s the existing and the r ecommendation.
Table 2: Existi ng and pr oposed di still ation i nst allation.
Wat er Temper atur e
(°C)
In
Out
C1
450
200
32
38
C2
450
200
32
38
C3
450
200
32
38
*Recommendation: Add new condenser of 450m 2
Condenser
Ar ea
(m 2 )
Wat er Flow
Rate (m 3 )
Hexane Vapour
Temper atur e (°C)
In
Out
120
44
90
40
90
40
2.2.2 Assessment phase 2: fugitive loss
Decisions taken to car r y out pr essur e test all equipment and piping w ith pr essur ized w ater to
ensur e that the syst em is fr ee of leaks pr ior to star t oper ation.
2.2.3 Assessment phase 3: purging loss
Pur ging loss only exist once the plant is star ting back after the shutdow n. Case study w as car r ied
for the year 2010 of high hexane losses dur ing the plant star t back after mor e than 1 day shutdow n
as show n in Figur e 7. The actions that can be taken to minimize the pur ging loss ar e:
(i)
(ii)
(iii)
Impr ove equipment r eliability thr ough design impr ovement and tr ough pr eventive
maintenance pr ocesses. This w ill r educe the fr equency for w hich maintenance and
inspection ar e r equir ed, thus r educing the fr equency of vapor fr eeing and its r elated pur ging
solvent loss.
Allow the nor mal vapor r ecover y system t o r un as long as possible prior opening up the
pr ocess equipment. This will r ecover the major ity of the solvent pr ior to vapor fr eeing, thus
r educing pur ging loss.
Dischar ge the pur ge fan thr ough a condenser to r ecover as much as the solvent vapor as
possible, thus r educing pur ging solvent loss.
Decision w as taken to car r y out action plant no 2 due to able t o car r y out the action
immediately w ithout any major cost.
Figure 7 : Hexane loss aft er pl ant st ar ti ng back fr om shut dow n.
2.3
I mplementation
Once the action plans w er e selected for excess, fugitive and pur ging loss, decision taken to implement the
action plans in stages, 1st excess loss follow ed by fugitive loss and finally pur ging loss.
2.3.1 Excess loss
On 23 December 2011, added 1 mor e condenser , 450 m 2 to incr ease the cooling capacity fr om
1350m 2 to 1800m 2 (r efer to Figur e 8). This mainly to condense the vapor fr om economizer s,
evapor ator s and str ipper and r educe the excess load in absor ption section.
© 2012 GETview Limit ed. All right s reserved
12
Global Engineers & Technologist s Review , Vol.2 No.12
(2012)
2.3.2 Fugitive Loss
On 02 June 2012, the complete solvent extr action plant w as shutdow n for annual maintenance
w or ks. The action taken to pr essur e tests all the equipment including economizer s, evapor ator s,
str ipper , vapor s lines and vessels. The pr essur e test car r ied out by using w ater and found the w ater
leaking fr om economizer top manhole, evapor ator s tr ansfer line flange, sever al piping flange and 1
elbow cr acked. Gaskets w er e changed to all the leaking ar ea and r eplaced new elbow .
2.3.3 Purging Loss
A shutdow n pr ocedur es w as planned and a case study w as car r ied out fr om June to August 2012,
decision taken that vacuum pump, steam and cooling tow er need to be oper ated continuously for 3
hour s befor e the plant completely shut dow n. This due to allow the nor mal vapor r ecover y system
and r ecover the major ity hexane vapor to be condensed.
Figure 8 : Di stillation section after modification.
3.0
RESULTS AND DISCUSSION
The r esults after the impr ovement w er e r ecor ded in t hr ee differ ent stages. The findings and discussion ar e
focused on hexane loss in excess loss, pur ging loss and fugitive loss.
3.1
Excess Loss
After installed new condenser to incr ease the cooling capacity fr om 1350 m 2 to 1800 m 2, r esults ar e
monitor ed for hexane content in ventilated air fr om Januar y 2012 to May 2012. Based on the r esults, a
gr aph w as plotted as per Figur e 9(a). This graph show s hexane contains in vent r educed fr om average
560 mg/ litr e taken in Januar y-May 2011 to aver age 132 mg/ litr e. Detail analysis of hexane loss also
car r ied in the same per iod. Figur e 9(b) is the r esults and found after the installed new condenser , the
hexane loss r educed fr om aver age 9.5 litr e/ MT to 7.5 litr e/ MT.
Figure 9 : (a) Monitor i ng hexane i n vent air , (b) hexane excess loss befor e and after modification.
3.2
Fugitive Loss
After r ectified all the leakages especially fr om economizer , evapor ator s’ flanges and elbow s and fittings,
detail analysis w as car r ied for 3 months. A gr aph w as plotted base on the r esults. Figur e 10(a) clear ly
show s the impr ovement and saving about 1 litr e/ MT after stop the leakages.
© 2012 GETview Limit ed. All right s reserved
13
Global Engineers & Technologist s Review , Vol.2 No.12
(2012)
Figure 10: Hexane befor e and aft er modificat ion, (a) fugitive loss, (b) Pur gi ng loss.
3.3 Purging Loss
Although the hexane loss due to pur ging cannot be quantified in ter ms of litr e of solvent loss per ton of
palm ker nel pr ocessed on a dir ect basis but it’s ver y impor tant to keep the hexane loss as low as possible
dur ing the plant star t up after shutdow n. Follow ing the specific shutdow n and star t-up pr ocedur es
complying detailed checklists, the r esults have been impr oved as show n in Figur e 10(b).
4.0
CONCLUSION
Hexane loss has always been the significant r eason incurr ing cost for oper ating of an extr action plant. Per haps,
in the past, ther e w er e times w hen additional solvent usage was accepted as par t of having low er r esidual oils in
the meal and mill feed or even low er ener gy costs in steam pr oduction, but discar ded by r ecent food and safety
r egulations. How ever excessive expenditur e for additional solvent r ecover y or pollution contr ol equipment
w ould not be necessar y if a plant is pr oper ly oper ated and maintained. Table 3 clear ly show s the total saving of
RM 727, 660 fr om Januar y 2012 to August 2012 after the impr ovements w e implemented.
Table 3: Total saving of hexane
PK thr oughput ( mt)
Januar y
2012
Febr uar y
2012
Mar ch
2012
Apr il
2012
May
2012
June
2012
July
2012
August
2012
7,943
13,652
12,723
12,557
15,086
14,066
14,754
12,840
Hexane Loss (/ mt)
7.3
7.8
7.4
7.5
7.5
6.6
6.5
6.5
Hexane Pr ice (RM/ s)
2.89
2.82
2.82
2.43
3.17
3.22
3.05
2.94
Aver age Hexane loss
in year 2011
9.5
9.5
9.5
9.5
9.5
9.5
9.5
9.5
50,494
65,536
75,450
61,020
95,704
131,261
134,871
113,324
Saving (RM)
ACKNOWLEDMENTS
Author s w ould like to thank Faculty of Manufactur ing Engineer ing and Univer siti Teknikal Malaysia Melaka for
suppor ting this r esear ch Special thanks to Ministr y of Higher Education (MOHE) for awar ding r esear ch gr ants
(GLuar / 2012/ FKP(1)/ G00010) and (PRGS/ 2012/ TK01/ FKP/ 02/ 1/ T0003) w hich ver y much helped in
completing the study w ithout much hur dles.
REFERENCES
[ 1] Dacer a, D., Jenvanitpanjakul, P., Nitisoravut, S. and Babel, S. (2003): Hexan Reduction in a Thai Rice Bran Oil
factor y: A Cleaner Technology Appr oach. Thammasat Int. Jour nal of Science and Technology, Vol.8, No.4,
pp.6-16.
[ 2] NVO Hexane Repor t (2010): Soy Pr otein and Chemical Solvents in Nutr ition Bar s and Meat Alter natives,
Cor nucopia Institute.
[ 3] Hai, T.C. (2002): The Palm Oil Industr y in Malaysia: Fr om Seed to Fr ying Pan, Plantation Agr icultur e - WWF
Malaysia.
[ 4] House, R.J.R., Har combe, A.O. and Guinness R.G. (1981): Hexane Losses in Solvent Extr acted Soya Meal:
Measur ement by Gas Chr omatography and Br ief Evaluation. Jour nal of the Amer ican Oil Chemist’ Society,
pp.626-629.
[ 5] Yuhazr i, M.Y., Haer yip Sihambing, Umar Nirmal, Saijod Lau and Phongsakor n Pr ak Tom. (2012): Solid Fuel
fr om Empty Fr uit Bunch Fiber and Waste Paper s part1: Heat Released fr om Combustion Test. Global
Engineer s and Technologists Review . Vol.2, No.1, pp.7-13.
© 2012 GETview Limit ed. All right s reserved
14