Biodiesel is a long chain fatty acid alkyl ester molecule with robust characteristics suitable for both environment and as alternate energy resources. This paper aimed in summarizing the detailed literature study on biodiesel produced from waste animal fats discarded from leather tanneries and animal slaughter houses. This study concentrated on the extraction techniques, refining process, biodiesel production process along with its advantages and effect on engine. The fats had been proven to a viable feedstock when compared to vegetable oil and waste cooking oil in terms of productivity and economy. Various technical challenges involved in biodiesel production are food vs. fuel conflict over feedstock, auxiliary energy requirement for fat extraction and biodiesel production, Free Fatty Acid content, optimizing the reaction. Effects of biodiesel on engine application had also been discussed and will be providing wider scope of research for overcoming these short comes. This literature study affirmed that biodiesel produced from waste animal fat has a very good impact in reducing environmental pollution and moving a step ahead towards an effective sustainable development.

Comprehensive study on biodiesel produced from waste animal fats-A review

This present study aims in understanding the influence of dominant fatty acid esters of waste animal fat biodiesel on its emission characteristics in CI engine. Biodiesel was produced from waste animal fat by means of base catalysed transesterification; and Ethyl oleate (40.21%), ethyl palmitate (25.36%) and ethyl stearate (16.87%) were characterized as dominant fatty acid esters using GC spectra. Test samples were prepared for these ester molecules based on their availability, in addition to biodiesel blend and plain diesel and were tested for their emission levels in single cylinder four stroke CI engine using flue gas analyser. High exhaust gas temperature was contributed by Ethyl oleate (1.15% lesser than biodiesel), as a result of low cetane number due to unsaturation and high viscosity. Likewise, the increased carbon chain length and unsaturation of ethyl oleate (2.55% lesser than biodiesel) resulted in high concentration of CO emission for biodiesel whereas high CO2 emission concentration was because of ester molecules with increased carbon chain length (stearate and Oleate esters). Reduced NOX emission for biodiesel was as a result of higher cetane number from ethyl stearate (CN=86.83) and ethyl palmitate (CN=86.55), which reduced its ignition delay thereby moderating the heat release rate. In addition, long carbon chained ester molecules (oleate and stearate esters) in biodiesel consumed more oxygen content for improving overall rate of combustion while increased HC emission was explained by unsaturation in biodiesel because of ethyl oleate (on average ,50 PPM).

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Effect of Dominant Fatty Acid Esters on Emission Characteristics of Waste Animal Fat Biodiesel in CI Engine

Biodiesel is considered as most promising alternative for fossil fuels because of its robust combustion characteristics and self-sustainability. Identifying a suitable feed stock with good lipid content, optimized reaction parameters will help standardizing this fuel globally. This paper deals with production of biodiesel from the oil of Mimusops elengi by heterogeneous catalyzed transesterification reaction. Methanol in stoichiometric molar ratio was used as the solvent for reaction whereas potassium aluminium silicate was used heterogeneous catalyst with a weight corresponding to weight of oil. Maximum oil content present in the seed was found to be 13%, which was determined using Soxhlet’s extraction and the dominant acids found in the extracted oil were stearic acid and Palmitic acids. The molar ratio was found out to be 1:9, with catalyst concentration of 2% weight of oil, for a temperature of 60oC. A maximum yield of 73.4% was obtained using this novel catalyst with stearate as dominant methyl ester. The novel catalyst can be reused again for the reaction without compromising the conversion yield.

Ranjitha J

Papers

Biodiesel Production from the Seeds of Mimusops elengi Using Potassium Aluminium Silicate as Novel Catalyst