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Sains Malaysiana 39(5)(2010): 805-809
Optimization of Process Parameters for
Alkaline-Catalysed Transesterification of Palm Oil Using Response Surface
Methodology
(Pengoptimuman
Parameter Proses untuk Transesterifikasi Minyak Sawit Bermangkin Alkali Menggunakan
Kaedah Sambutan)
N. Razali, H. Mootabadi, B. Salamatinia, K.T. Lee & A.Z. Abdullah*
School of Chemical Engineering, Universiti
Sains Malaysia
Engineering Campus, Seri Ampangan
14300 Nibong Tebal, Penang, Malaysia
Diserahkan: 14 April 2009 / Diterima:
18 Disember 2009
ABSTRACT
Biodiesel
(fatty acid methyl esters) was synthesized from direct transesterification of
vegetable oils, where the corresponding triglycerides react with methanol in
the presence of a suitable catalyst. The alkali catalysts are the most common
catalyst used in biodiesel industry, because the process proves faster and the
reaction conditions are moderate compared to the acid catalyst. In the present
study, biodiesel production using heterogeneous alkaline-catalysed transesterification
process (KOH supported on SBA 15) was proposed. The influence of reaction temperature x1 (50 – 90 oC), ratio of methanol to oil, x2 (6:1 – 14:1 mol/mol), amount of catalyst, x3 (1 – 5wt.%), and reaction time, x4 (2 – 6 h) to the reaction was studied. These four conditions
were studied using design of experiment (DOE), based on four-variable central composite design (CCD) with α = 2. The process variables were optimised using
the Response Surface Methodology (RSM) in obtaining the maximum yield of biodiesel. This method was
also applied to determine the significance and interaction of the variables
affecting the biodiesel production. The biodiesel produced in the experiment
was analysed by gas chromatography, which considered five major fatty acid
methyl esters. The optimal conditions of
response were found to be 70 oC
for reaction temperature, 11.6 wt/wt of ratio methanol to oil, 3.91wt.% of
weight of catalyst and 5 h for reaction time with 93% of biodiesel yield for
predicted value and 87.3% from experimental.
Keywords:
Base catalyst; biodiesel; response surface methodology
ABSTRAK
Biodiesel
telah disintesis daripada transesterifikasi langsung minyak sayuran yang
melibatkan trigliserida bertindak balas dengan metanol dengan kehadiran mangkin
yang sesuai. Mangkin beralkali adalah mangkin yang biasanya digunakan di dalam
industri biodiesel kerana proses terbukti lebih cepat dan keadaan tindak balas
sederhana berbanding dengan mangkin berasid. Dalam kajian ini, penghasilan
biodiesel menggunakan proses transesterifikasi bermangkinkan heterogen
beralkali (KOH disokong di atas SBA-15) telah dikaji. Kesan suhu tindakbalas, x1 (50 – 90 oC), nisbah metanol kepada minyak, x2 (6:1 – 14:1 mol/mol), berat mangkin, x3 (1 – 5wt.%), dan masa, x4 (2 – 6 h) terhadap tindak balas dikaji. Empat keadaan ini telah
dikaji menggunakan reka bentuk eksperimen (DOE) berdasarkan kepada empat pembolehubah reka bentuk gabungan
berpusat (CCD) dengan α = 2.
Pembolehubah proses telah dioptimumkan menggunakan kaedah sambutan permukaan (RSM) dalam mendapatkan hasil biodiesel yang maksimum. Kaedah ini
juga digunakan untuk menentukan kepentingan dan interaksi
pembolehubah-pembolehubah yang mempengaruhi hasil biodiesel. Biodiesel yang
dihasilkan telah dianalisis melalui kromatografi yang mengambilkira lima metil
ester asid lemak utama. Keadaan optimum sambutan didapati pada suhu tindak
balas 70 oC, nisbah metanol kepada minyak 11.6 mol/mol, berat
mangkin 3.91 wt.% dan 5 jam masa tindak balas dengan 93% hasil keluaran biodiesel
untuk nilai jangkaan dan 87.3% daripada eksperimen.
Kata kunci:
Biodiesel; kaedah sambutan permukaan; mangkin beralkali
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*Pengarang untuk surat-menyurat; email: chzuhairi@eng.usm.my
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