Production of biodiesel from sludge palm oil (SPO) by enzymatic transesterification /
Biodiesel is a non-toxic, renewable and biodegradable fuel that can replace the fossil fuels which have issues on toxic emissions, higher price and depleting reserve. The high cost of biodiesel feedstock can be reduced by using low cost and abundant waste oils such as sludge palm oil (SPO) especiall...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
Kuala Lumpur:
Kulliyyah of Engineering, International Islamic University Malaysia,
2013
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| Subjects: | |
| Online Access: | Click here to view 1st 24 pages of the thesis. Members can view fulltext at the specified PCs in the library. |
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| Summary: | Biodiesel is a non-toxic, renewable and biodegradable fuel that can replace the fossil fuels which have issues on toxic emissions, higher price and depleting reserve. The high cost of biodiesel feedstock can be reduced by using low cost and abundant waste oils such as sludge palm oil (SPO) especially in Malaysia which produces 40 million tons SPO per year. In this study, SPO with a high free fatty acids (FFA) content (51.64 ± 0.59% as palmitic acid) was used to produce biodiesel using locallyproduced Candida cylindracea lipase fermented from palm oil mill effluent (POME) as a low-cost basal medium. The concentration of lipase was 0.15 mg/ml and its activity was 4.76 U/ml at pH 5. The inhibition of lipase activity was reduced by investigating the suitable solvent system and process conditions using one factor at a time (OFAT) method. In the study of solvent system, ethanol was found to be a better alcohol as the acyl-acceptor rather than methanol. The optimum factors of ethanol solvent system were studied and the results were 4:1 ethanol/SPO molar ratio in the presence of small water content (1:15 – 1:10 water/SPO volume ratio). The optimum factors of process conditions were 10 U/25g of SPO enzyme loading, 400C reaction temperature, 250 rpm mixing speed and 24 hours reaction time. The highest conversion of FFA into biodiesel (Conversion) and the total yield of biodiesel (YT) of the OFAT study was 12.0% and 62.3 % (w/w SPO) respectively. Statistical optimization of process conditions was done using response surface methodology (RSM). The optimal level of inputs predicted by RSM were 10 U/25g of SPO, 410C reaction temperature and 250 rpm mixing speed with Conversion and YT equal to 15.5% and 57.5% (w/w SPO) respectively. The kinetic study revealed that the reaction rate was faster at 0 to 3 hours which is 3.9% yield of fatty acid ethyl ester per hour (YFAEE/h) then it became slower at 0.6% YFAEE/h. The enzymatic biodiesel production of the optimum condition was first order reaction with reaction rate (K) and regression coefficient (R2) equal to 0.028 hour-1 and 0.900 respectively. The enzymatic biodiesel production was improved by adding co-solvent which acts as lipase stabilizer. The highest Conversion and YT were 28.8% and 71.6 % (w/w SPO) respectively with the addition of ter-butanol at 2:1 tert-butanol/SPO molar ratio. The biodiesel was characterised by 27.91% of triacylglyceride (TAG), 14.09 % of diacylglyceride (DAG), 1.91% of monoacylglyceride (MAG), 35.13% of FFA and 20.94% of fatty acid ethyl esters (FAEE). The SPO and locally produced lipase were found to have a promising potential for enzymatic biodiesel production. |
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| Physical Description: | xviii, 156 leaves : ill. ; 30cm. |
| Bibliography: | Includes bibliographical references (leaves 134-146). |