MODELLING AND OPTIMIZATION OF TRANSESTERIFICATION OF PALM KERNEL OIL CATALYSED BY CALCIUM OXIDE DERIVED FROM HEN EGGSHELL WASTES

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1 Several waste materials have been utilised as hetergeneus catalyst fr the prductin f bidiesel. Birla et al. (01) used snail shell as catalyst in the synthesis f bidiesel frm waste frying il and btained a bidiesel yield f 87.8% under ptimum cnditins f 6.0:1 methanl t il rati, wt.% catalyst cncentratin and temperature f 60 C after 8 h f reactin. Viriyahttps://dx.di.rg/ /ijs.v0i1.13 Ife Jurnal f Science vl. 0, n. 1 (018) MODELLING AND OPTIMIZATION OF TRANSESTERIFICATION OF PALM KERNEL OIL CATALYSED BY CALCIUM OXIDE DERIVED FROM HEN EGGSHELL WASTES Akhabue, C. E.* and Ogg, J. A. Department f Chemical Engineering, Faculty f Engineering, University f Benin, Benin City, Nigeria *Crrespnding Authr: christpher.akhabue@uniben.edu th th (Received: 7 Nvember, 017; Accepted: 4 February, 018) ABSTRACT In this study, mdelling and ptimizatin f transesterificatin f palm kernel il (PKO) catalysed by calcium xide (CaO) derived frm hen eggshell wastes were investigated. The eggshells were calcined fr 5 h at 900 C. The catalyst derived frm the eggshells after calcinatin was characterized by Furier transfrm infrared (FTIR), scanning electrn micrscpe (SEM) and X ray flurescence (XRF). The XRF results shws that the catalyst cntains 98.16% f CaO. Variables fr the transesterificatin f the PKO were ptimized using respnse surface methdlgy (RSM) based n central cmpsite design (CCD). The variables investigated were methanl t il mlar rati, catalyst cncentratin, reactin temperature and time. A secnd rder quadratic mdel (p < ) was develped fr predicting the bidiesel yield. The mdel predicted maximum bidiesel yield f % under the fllwing ptimum prcess cnditins: methanl t il mlar rati f 9.0:1, catalyst cncentratin f wt.%, temperature f 51.4 C and reactin time f min. The value f the bidiesel yield predicted was clse t the experimental value f 94.63%. Physicchemical prperties f the bidiesel btained were within the American Sciety fr Testing and Materials (ASTM) standards fr bidiesel. Hence, hetergeneus catalyst derived frm eggshells wastes can be used fr transesterificatin. Keywrds: Eggshells, Calcium Oxide, Transesterificatin, Optimizatin, PKO 17 INTRODUCTION Bidiesel, a prmising alternative fuel t petrleum-based diesel fuel used in cmpressin ignitin (CI) engines has becme the fcus f many researchers in recent times. Bidiesel is prduced by reacting vegetable ils r animal fats with a lw mlecular weight alchl, preferably methanl and ethanl in the presence f a catalyst. This reactin is knwn as transesterificatin. The use f bidiesel fuel instead f petrleum-based fuel in CI engines has several advantages. These include, its high flash pint, nn-txic nature and abve all, it is bidegradable and als renewable. Less emissin f CO and xides f nitrgen and sulphur are als advantages f using bidiesel in CI engines (Mnyem and Van Gerpen, 001; Hess et al., 007). Hmgeneus catalysts such sdium hydrxide (NaOH) and ptassium hydrxide (KOH) have been used in transesterificatin reactins (Shahla et al. 01; Dharma et al., 016; Akhabue and Okwundu, 017). Althugh, these hmgeneus catalysts exhibit high catalytic activity, several prblems have been identified with their uses (Tariq et al., 01). Sme f these prblems include the fllwings: lw bidiesel yield due t the frmatin f emulsin, the catalyst is nt reusable and mre water is used during the washing prcess. The waste water frm the washing prcess als requires further treatment which leads t additinal csts. As a result, many researchers have fcused attentin n the use f hetergeneus catalysts fr bidiesel prductin due t its cnvenience in separatin and reusability (Birla et al., 01; Viriya-empikul et al., 01; Rezaei et al., 013; Zeng et al., 015; Eswarara et al., 016; Gupta and Agarwal, 016; Ye et al., 016; Kstic et al., 016). The hetergeneus catalysed systems cnsist f three phases (il/methanl/catalyst). On adsrptin f methanl n the catalyst surface, the active methxide specie is frmed. The rate at which the methxide is frmed is related t the efficiency f the catalyst.

2 18 Akhabue and Ogg: Mdelling and Optimizatin f Transesterificatin f Palm Kernel Oil empikul et al. (01) in anther study used Cabased slid catalyst derived frm industrial wastes fr the prductin f bidiesel frm palm lein ils. Hetergeneus mussel shell was used as catalyst fr the prductin f bidiesel frm sybean il by Rezaei et al. (013). A maximum bidiesel yield f 94.1% was btained at a catalyst cncentratin f 1 wt.%, methanl t il rati f 4.1:1 and at a temperature f 60 C after 8 h. In a recent study cnducted by Eswarara et al. (016), a mixture f natural shells was used as slid catalyst in the transesterificatin f Jatrpha il. Gupta and Agarwal (016) used snail shell mdified with KOH as catalyst fr the prductin f bidiesel frm sybean il. A bidiesel yield f 96% was btained. Kstic et al. (016) used palm kernel shell bichar as hetergeneus catalyst fr the transesterificatin f sunflwer il. In the present study, eggshell waste was used as hetergeneus catalyst fr the transesterificatin f palm kernel il (PKO). The catalyst derived frm the eggshell was characterized by scanning Table 1. Physic-chemical Prperties f Palm Kernel Oil electrn micrscpe (SEM), Furier transfrm infrared (FTIR) spectrphtmeter and X ray flurescence (XRF). Transesterificatin was ptimized by respnse surface methdlgy (RSM) with the aid f central cmpsite design (CCD). The effect f methanl t il mlar rati, catalyst cncentratin, temperature and time n the yield f bidiesel was investigated. MATERIALS AND METHODS Materials Waste egg shells were cllected frm varius eatery centres at the University f Benin, Benin City, Nigeria. Palm kernel il (PKO) was supplied by Je Chemicals in Onitsha, Anambra State in Nigeria. The physicchemical prperties f the PKO are shwn in table 1. The chemicals used were methanl (99.5%), ethanl (99.5%), sulphuric acid, ptassium hydrxide pellets and benzene (99.5%). The chemicals were f analytical grade and supplied by Pyrex IG Scientific Cmpany, Benin City, Nigeria. Prperty (Unit) Value Density at 7 C (kg/m 3 ) 90 Viscsity at 7 C (mm /s) 9.8 Idine Value (mg KOH/g il) 81.5 Acid Value (mg KOH/g il) FFA Cntent (%) Sapnificatin Value (mg KOH/g il) 03.7 Water cntent (%) 0.86 Fatty acid cmpsitin (mass %) Octanic acid C8: n-decanic acid C10: Ddecanic acid C1: Tetradecanic acid C14: n-hexadecanic acid C16: Oleic acid C18: Preparatin f Catalyst frm the Waste Eggshells The waste eggshells were washed with tap water t remve impurities frm their surfaces. The washed eggshells were thereafter sun dried fr three days. The dried eggshells were crushed t fine pwder particles using a wden mrtar and pestle. Calcinatin f the particles was carried ut using a muffle furnace fr 5 h and the temperature was set t 900 C. The ht calcined samples were remved frm the muffle furnace befre the temperature f the furnace culd reach rm temperature and immediately placed inside a

3 Akhabue and Ogg: Mdelling and Optimizatin f Transesterificatin f Palm Kernel Oil desiccatr t cl. The samples were remved frm the desiccatr and kept in an air tight cntainer t prevent reactin with misture. Characterizatin f the Catalyst btained frm the Eggshells The chemical cmpsitin f the catalyst was analysed using an X ray flurescence spectrmeter (PANalytical MiniPal 4) with an inbuilt XRD. The surface mrphlgy f the catalyst derived frm egg shells was bserved by a scanning electrn micrscpe (SEM). The SEM images were bserved using Phenm PrX wrking at an accelerated vltage f 10 kv and beam size f 3. Micrgraphs were bserved at 00 and 400 mm. The functinal grups present in the catalyst were analysed using a Furier transfrm infrared (FTIR) spectrphtmeter (FTIR-8400 S, SHIMADZU) within the wavelength regin f t 4000 cm. Bidiesel Preparatin Pretreatment f the Palm Kernel Oil As shwn in table 1, the free fatty acid (FFA) cntent f the PKO was mre than 1%, pretreatment f the PKO was therefre carried ut t reduce the FFA cntent t less than 1%. The pretreatment prcess f the il als called esterificatin was carried ut in a 1 L rund bttm flask using a methanl t il mlar rati f 7:1, sulphuric acid cncentratin f 1 wt % and at temperature f 60 C. The reactin was carried ut using a temperature cntrlled magnetic stirrer (Mdel N. HJ 3D) fr h. At the end f the reactin, the ily part was separated frm the excess methanl and water. The FFA cntent f the treated il was fund t be less than 1%. Transesterificatin Reactin Transesterificatin f the treated PKO was carried ut in a 50 ml cnical flask using the temperature cntrlled magnetic stirrer. Briefly, g f the treated PKO was measured int the cnical flask which was placed n the stirrer and heated t the desired temperature. A knwn weight f the catalyst was added t methanl and the mixture was thrughly agitated. The catalystmethanl mixture was added t the heated PKO as sn as the desired temperature fr reactin was reached. The magnetic stirrer was turned n and reactin was allwed t prceed. At the end f the reactin, the mixture was separated frm the catalyst by decantatin and filtratin. The mixture was later transferred t a separating funnel and allwed t settle vernight. The glycerl bttm layer was separated frm the bidiesel layer. The bidiesel was purified by washing with warm water. The prcess f washing invlves adding warm water apprximately ne-third the vlume f the bidiesel t the bidiesel inside the separating funnel. The washing prcess was carried ut thrice. The washed bidiesel was later heated in an ven at a temperature f 80 C in rder t remve water that might still be present in the bidiesel. The bidiesel yield was btained using Eq. (1). (1) Experimental Design and Statistical AnalysisCentral cmpsite design (CCD) with fur parameters was used t study the respnse pattern and t determine the ptimum cmbinatin f variables. The effect f methanl t il mlar rati (X ), catalyst cncentratin (X ), 1 temperature (X ) and time (X ) at five variables 3 4 levels in the transesterificatin prcess is presented in table. The cded and actual levels f the variables used fr the transesterificatin f the PKO are als presented in table. The variables were cded accrding t Eq. (). ()

4 130 Table. Cded and actual levels fr the fur parameters in the CCD Symbl Factr Unit Levels X 1 Akhabue and Ogg: Mdelling and Optimizatin f Transesterificatin f Palm Kernel Oil ( ) ( 1) (0) (1) (+) X Catalyst cnc. wt.% f il Methanl:il ml/ml X 3 Temperature C X 3 Time min where X i and x i are the actual and cded factrs respectively, x is the value x i at the centre pint and Dx is the step change. A ttal f 30 experimental runs were carried ut in a randm rder t minimise the effects f explained variability in the bserved respnses due t extraneus factrs. The experiments were carried ut in duplicate and the mean bidiesel yield btained are shwn in table 3. Design Expert Table 3. Central Cmpsite Design Matrix fr Bidiesel yield sftware versin 10 (Stat-Ease Inc., Minneaplis) was used fr the regressin and the pltting f the respnse surface plts. The experimental data btained frm the transesterificatin reactin was analysed by the respnse surface regressin using the plynmial equatin shwn in Eq. (3). Run Cded values Actual values n. X 1 X X 3 X 4 X 1 X X 3 X 4 Bidiesel yield (%) Experiment. Predicted

5 Akhabue and Ogg: Mdelling and Optimizatin f Transesterificatin f Palm Kernel Oil (3) 131 characterized accrding t the American Sciety fr Testing and Materials (ASTM) D6751 standards. Basic fuel prperties such as flash pint, acid value, density, viscsity amngst thers were carried ut. where Y is the respnse factr (bidiesel yield), X i is the independent variables, b is the intercept, b i is first rder cefficient f the mdel b ii is the quadratic cefficient f the ith factr, b is the ij linear cefficient f the mdel fr the interactin between the ith and jth variables, k is the number f variables and e is the experimental errr. The statistical significance f the mdel was checked using the analysis f variance (ANOVA) and the cefficient f determinatin (R ). The ANOVA was als used t determine the significance f each term in the mdel. The mdel was cnsidered satisfactry when the ANOVA data shwed a high level f significance. Physicchemical Characterizatin f the Bidiesel The physicchemical prperties f the bidiesel btained at the ptimal prcess cnditins were RESULTS AND DISCUSSION Characterizatin f the Catalyst The chemical cmpsitin f the catalyst derived frm the eggshell is shwn in table 4. The catalyst cntained a very high cmpsitin f calcium xide (98.16%) fllwed by MnO and Fe O. 3 Sme elements such as Cr, Sr, and Cu were als detected in trace amunts. The high cmpsitin f CaO in the calcined eggshell is a result f the fact that during calcinatin at high temperature, calcium carbnate present in eggshell (Laca et al., 017) is decmpsed t frm CaO and CO accrding t reactin equatin shwn in Eq. (4). (4) The mrphlgy f the catalyst derived frm the eggshell were examined by bserving the SEM images f the calcined eggshells at different magnificatins as shwn in Figure 1. Table 4. Chemical cmpsitin f catalyst derived frm eggshell Oxides Cmpsitin (%) CaO Fe O MnO 0.06 TiO Trace elements Figure 1. Scanning electrn micrscpe images f calcined eggshells at magnificatin f (a) 500 and (b) 1000

6 13 Akhabue and Ogg: Mdelling and Optimizatin f Transesterificatin f Palm Kernel Oil The shape f the particles was almst regular as can be seen frm Figures. 1a and 1b Similar bservatins have been reprted by Yin et al. (016) and Zeng et al. (015). The FTIR spectrum f the catalyst derived frm the calcined eggshells is shwn in Figure. Majr absrptin peaks were bserved at , , and cm. The -1 peak at cm crrespnds t an asymmetric streching OH frm Ca(OH) frmed as a result f the fact that CaO readily absrbs misture n expsture t the atmsphere. The -1 peaks at and cm are ascribed t the carbnyl functinal grup while that at cm is attributed t the streching -1 vibratin f Si-O and the peak at cm is characteristics f carbnyl functinal grup. Figure. FTIR spectrum f the catalyst derived frm calcined eggshell Mdelling and Optimizatin f the Transesterificatin Reactin Quadratic Regressin Mdel Experimental results were fitted using the plynmial equatin (Eq. (3)) by multiple regressin analysis t btain the quadratic regressin mdel fr the transesterificatin f PKO based n the cded values shwn in Eq. (5). (5) Where Y is the bidiesel yield, X is the methanl 1 t il mlar rati, X is the catalyst cncentratin, X is the reactin temperature and X the reactin 3 4 time. The statistical significance and fitness f the develped mdel as well as the significance f the individual and interacting terms were analysed using ANOVA. The ANOVA results are presented in table 5. The mdel F value f and p value less than was an indicatin f the high significance f the mdel. The significance f each mdel terms was als checked using the F value and p value. Results indicated that mst significant term in the mdel was the methanl t il mlar rati (X ) with an F 1 value f , fllwed by the reactin time (X ) 4 with F value f Temperature (X ) was 3 nt a significant term in the mdel based n the p value f Fr a term t be significant, p value must be less than All the interacting terms were significant with (X X ) being the mst 1 4 significant. The lack f fit was als determined fr the quadratic mdel. The lack f fit F value f 1.13 and p value f was nt significant, an indicatin that the mdel sufficiently describes the relatinship between the transesterificatin variables and the bidiesel yield. The cefficient f variatin (CV) was als used t check the

7 adequacy f the mdel. Accrding t Daniel (1991), the CV shuld nt be mre than 10%. The CV was 3.76%, which further cnfirms the mdel adequacy. The R value was als used t test the suitability f the mdel. The R value f which is clse t ne indicates an excellent agreement between experimental and predicted 133 bidiesel yield. In rder wrds, nly 0.54% f the variatins in the bidiesel yield culd nt be explained by the quadratic mdel. The predicted R value f was in reasnable agreement with the adjusted R value f , i.e. the difference is less than 0.. Table 5. ANOVA results fr the secnd - rder quadratic mdel Surce Sum f df Mean F value p-value squares Square Prb.> F Mdel < significant X 1 X X 3 X 3 X 1 X X 1 X 3 X 1 X 4 X X 3 X X 4 X 3 X 4 X 1 X X 3 X 4 Akhabue and Ogg: Mdelling and Optimizatin f Transesterificatin f Palm Kernel Oil < < < < < < < < Residual Lack f fit nt significant Pure errr Cr Ttal C.V. = 3.767% R = Adj. R = Pred. R = Adeq. Precisin = A plt f the predicted bidiesel yield versus the experiment bidiesel yield is shwn in Figure 3. The randm scattering f data pints arund the diagnal line is futher evident f the suitability f the develped mdel. Adeq Precisin which measures the signal t nise rati had a value f which is greater than 4. It thus indicates an adequate signal and the mdel can be used t navigate the design space.

8 134 Akhabue and Ogg: Mdelling and Optimizatin f Transesterificatin f Palm Kernel Oil Figure 3. Predicted and experimental bidiesel yield Interactive Effect f Variables n the Bidiesel Yield The respnse surface plts shwn in figure 4 is used t described the interactive effect f tw variables n the bidiesel yield, while the ther tw variables are kept cnstant at their central pint. The respnse surface plt f the bidiesel yield as a functin f methanl t il rati and catalyst cncentratin at a temperature f 5.5 C and time f 135 min is shwn in figure 4a. Frm the figure, it is bserved that an increase in methanl t il rati frm 9:1 t 15:1 at a catalyst cncentratin f 3 wt.% reduces the bidiesel frm 9.04 t %. Hwever, there was a slight decrease in bidiesel yield at methanl t il rati f 9:1, when the catalyst cncentratin was increased. The respnse surface plt f the interactive effect f methanl t il rati and temperature at 5 wt.% catalyst cncentratin and reactin time f 135 min n the bidiesel yield is shwn in figure 4b. Increasing the reactin temperature increases the bidiesel yield. Hwever, beynd reactin temperature f 53.5 C, there is a decrease in the bidiesel yield. The interacting effect f methanl t il rati and time at a catalyst cncentratin f 5 wt.% and a reactin temperature f 5.5 C is shwn in figure 4c. Increasing methanl t il rati at a cnstant time f 8.5 min reduces the bidiesel yield. On the ther hand, there is an increase in the bidiesel yield with increase in the reactin time frm 8.5 min t min at a cnstant methanl il rati f 9:1. Figure 4d shws the respnse surface plts which describe the interactive effect f catalyst cncentratin and temperature n the bidiesel yield. Increasing catalyst cncentratin at fixed reactin temperature d nt have significant effect n the bidiesel yield as seen in the figure. It was als bserved that maximum bidiesel yield is btained at abut C. The interactive effect f catalyst cncentratin and time at methanl t il rati f 1 and reactin temperature f 5.5 C is shwn in figure 4e. A slight reductin in bidiesel yield was bserved at increasing catalyst cncentratin while keeping the reactin time cnstant at 8.5 min. Increasing bth catalyst cncentratin and time increases the bidiesel yield frm 68.03% t 75.81%. Figure 4f shws the respnse plt f the interactive effect f reactin temperature and time n the bidiesel yield. Frm the figure, at a fixed reactin temperature, there is an increase in bidiesel yield when the reactin time was increased.

9 Akhabue and Ogg: Mdelling and Optimizatin f Transesterificatin f Palm Kernel Oil 135 a b c d e f Figure 4. Respnse surface plts f bidiesel yield between (a) methanl:il rati and catalyst cncentratin (b) methanl:il rati and temperature (c) methanl t il rati and time (d) catalyst cncentratin and temperature (e) catalyst cncentratin and time (f) temperature and time

10 136 Akhabue and Ogg: Mdelling and Optimizatin f Transesterificatin f Palm Kernel Oil Optimizatin f Bidiesel Yield and Mdel Verificatin The ptimum cnditins fr achieving maximum bidiesel yield was calculated using RSM numerical ptimizatin. The slutins t the numerical ptimizatin were methanl t il mlar rati f 9:0:1, catalyst cncentratin f wt.%, temperature f C and a reactin time f min. Verificatin f the quadratic mdel was dne by carrying ut transesterificatin under the ptimal cnditins. The mean experimental yield was 94.63%, slightly different frm the predicted value f %. The experimental bidiesel yield was cmpared with yield btained by ther researchers wh used eg gshell as hetergeneus catalyst in transesterificatin reactin as shwn in table 6. Table 6. Cmparisn f bidiesel yield using different ils and eggshells as catalyst Eggshell Feedstck M:O Catalyst Temp. Time Yield Reference surce cnc. (wt.%) ( C) (min) (%) Duck Sybean il 10: Yin et al. (016) Ostrich used cking il 1: Tan et al. (015) Chicken used cking il 1: Tan et al. (015) Hen Sybean il 1: >95 Zeng et al. (015) Duck Palm il 9: Buasri et al. (013) Hen Palm il 9: Buasri et al. (013) Hen PKO 9.0: This Study Methanl: Oil mlar rati (M: O) Physicchemical Prperties f PKO Bidiesel The physicchemical prperties f the bidiesel prduced under ptimal reactin cnditins were analysed and cmpared with the ASTM D6751 bidiesel standard shwn in table 7. It can be seen that the majr fuel prperties such as density and flash pint are within the bidiesel standard. Table 7. Physic-chemical prperties f PKO bidiesel Prperty Unit Value Test Methd Bidiesel Standard ASTM D 6751 Viscsity at 5 C mm /s 4.64 D Density kg/m D Acid value mg KOH/g 0.6 D664 < 0.80 Flash pint C 16 D min Clud pint C 8 D500 - Idine value gi /100g 7.83 D Misture cntent (%) <0.05 CONCLUSION This study has fcussed n mdelling and ptimizing the prcess parameters n the prductin f bidiesel frm palm kernel il using hetergeneus catalyst derived frm chicken eggshell wastes. The eggshells were calcined at 900 C fr 5 h. Calcium xide cntent f the calcined eggshell was fund t 98.16%. The ptimizatin f the prcess parameters was dne using respnse surface methdlgy (RSM) based n the central cmpsite design. The parameters ptimized in the prductin prcess are methanl t il mlar rati, catalyst cncentratin, temperature and time. A secnd rder quadratic mdel with R = was develped t predict the bidiesel yield. The predicted maximum bidiesel yield was % under the fllwing cnditins (methanl t il rati f 9.0:1, catalyst

11 Akhabue and Ogg: Mdelling and Optimizatin f Transesterificatin f Palm Kernel Oil cncentratin f wt.%, temperature f C and a time f min. The experimental value btained under these same cnditins was 94.63%. The quality f the bidiesel prduced under these ptimum cnditins is in the range f the ASTM standard fr bidiesel. REFERENCES Akhabue, C. E. and Okwundu S. O. (017). Mnitring the transesterificatin reactin f castr il and methanl by ultravilet visible spectrscpy. Bifuels. Available in Birla, A., Singh, B., Upadhyay, S. N. and Sharma, Y. C. (01) Kinetics studies f synthesis f bidiesel frm waste frying il using a hetergeneus catalyst derived frm snail shell. Biresurce Technlgy 106: Buasri, A., Chaiyut, N., Vrrada L., Wngweang, C., Khamsrisuk, S. (013) Applicatin f eggshell wastes as a hetergeneus catalyst fr bidiesel prductin. Sustainable Energy 1(): Daniel, W. W. (1991) Bistatistics: A fundatin in the th health sciences (5 editin). New Yrk: Wiley. P. 1. Dharma, S., Masjuki, H. H., Ong, H. C., Sibayang, A. H., Silitnga, A. S., Kusum, F., Mahlia, T. M. I. (016). Optimizatin f bidiesel prductin prcess fr mixed Jatrpha curcas-ceiba pentandra bidiesel using respnse surface methdlgy. Energy and Cnversin Management 115: Eswarara, Y., Niju, S., Begum, K. M. M. S., Anantharaman, N. and Raj, S. M. (016) Transesterificatin f jatrpha il using mixture f natural shells as slid catalyst. Bifuels. Available in rg/ / Gupta, J. and Agarwal, M. (016) Preparatin and characterizatin f highly active slid based catalyst frm snail shell fr bidiesel prductin. Bifuels. Available in dx.di.rg/ / Hess, M. A., Hass, M. J., and Fglia, T. A., (007). Attempts t reduce NO exhaust emissin x by using refrmulated bidiesel. Fuel Prcessing Technlgy 88: Hideki, F., Akihik, K., Hide, N., (001). B i d i e s e l f u e l p r d u c t i n b y transesterificatin f ils. Jurnal f Biscience and Biengineering 9 (5), pp Kstic, M. D., Bazargan, A., Stamenkvic, O. S., Veljkvic, V. B. and McKay, G. (016) Optimizatin and kinetics f sunflwer il methanlysis catalysed by calcium xide-based catalyst derived frm palm kernel shell bichar. Fuel 163: Laca, A., Laca, A., Diaz, M. (017) Eggshell wastes as a catalyst: A review. Jurnal f Envirnmental Management 107: Mnyem, A. and Van Gerpen, J., H., (001). The effect f bidiesel xidatin n engine perfrmance and emissins. Bimass and Bienergy 0: Rezaei, R., Mhadesi, M. and Mradi, G. R. (013) Optimizatin f bidiesel prductin using waste mussel shell catalyst. Fuel 109: Shahla, S., Ngh, G. C., Yusff, R. (01). The evaluatin f varius kinetic mdels fr base-catalyzed ethanlysis f palm il. Biresurce Technlgy 104: 1-5 Tan, Y. H., Abdullah, M. O., Nlasc Hiplit, C. and Taufiq Yap, Y. H. (015) Waste strich and chicken eggshells as hetergeneus base catalyst fr bidiesel prductin frm used cking il: catalyst characterizatin and bidiesel yield perfrmance. Applied Energy 160: Tariq, M., Ali, S., Khalid, N. (01) Activity f hmgeneus and hetergeneus c a t a l y s t s, s p e c t r s c p i c a n d chrmatgraphic characterizatin f bidiesel: A review. Renewable and Sustainable Energy Reviews 16: Viriya -empikul, N., Krasae, P., Nualpaeng, W., Ysuk, B. and Faungnawakij, K. (01) Bidiesel prductin ver Ca-based slid catalysts derived frm industrial wastes. Fuel 9: Ye, W., Ga, Y., Ding, H., Liu, M., Liu, S., Han, X., Qi, J. (016) Kinetics f transesterificatin f palm il under cnventinal heating and micrwave irradiatin using hetergeneus catalyst. Fuel 180: Yin, X., Duan, X., Yu, Q., Dai, C., Tan, Z., Zhu,

12 138 Akhabue and Ogg: Mdelling and Optimizatin f Transesterificatin f Palm Kernel Oil X. (016) Bidiesel prductin frm sybean il dedrizer distillate using calcined duck eggshell as catalyst. Energy Cnversin Management 11: Zeng, D., Zhang, Q., Chen, S., Liu, Chen, Y., Tian, Y. (015) Preparatin and characterizatin f a strng base frm waste eggshell fr bidiesel prductin. Jur nal f Envirnmental Chemical Engineering 3: