Study On Solid Basic Catalysts Derived From Ca-based Wastes For Biodiesel Production

As energy demand continues to rise while the supply of fossil fuels is limited,finding an environmentally benign and sustainable alternative fuel is on the agenda.Biofuel such as biodiesel from renewable energy source (vegetable oils) areconsidered to be one of the next generation fuels for the transportation. Generally,biodiesel could be synthesized through transesterification of triglycerides withmethanol using homogeneous basic or acidic catalysts. However the use ofhomogeneous catalysts may cause many problems such as reactor corrosion, soapproduction, difficult to reuse the catalysts and the production of large amount of wastewater, which increase the overall cost of the biodiesel production. Heterogeneousbasic catalysts have been widely studied in the last decades and possessed severaloutstanding advantages such as simpler separation, no toxicity, no environmentalpollution and no corrosion, which can overcome the problems associated with the useof homogeneous catalysts.The study is to explore the transesterification process in the presence ofheterogeneous based catalyst using palm oil and methanol as raw materials. The maincomponents, which consists of methyl tetradecanoate, hexadecanoic acid methyl ester,8,11-Octadecadienoic acid methyl ester,9-Octadecenoic acid methyl ester andoctadecanoic acid methyl ester, of biodiesel are analyzed by GC-MS apparatus.Biodiesel yield is tested with external standard method via gas chromatography.This work was also focused on developing a new series of low cost and highefficiency heterogeneous basic catalysts for biodiesel production from waste duckshells, waste abalone shells and waste pig bones. The physicochemical properties ofthe catalysts were characterized by N2adsorption-desorption, XRD, Hammetindicator method and XRF. Once the catalysts utilized for conducting thetransesterification reaction, the effects of catalysts preparation and operatingconditions were thoroughly studied. The main conclusions were as follows:The waste duck shell was used as the raw material for Ca-based catalyst. Thecalcination of duck shell was conducted at800℃for4h. The experimental resultsshowed that the maximum yield of fatty acid methyl esters was92.5%at thefollowing reaction conditions: reaction temperature of65℃, reaction time of3h, amount of catalyst at7wt.%and a ratio of methanol-oil at9:1. Reusability resultsalso showed that the prepared catalyst could be reused up to8times, procreating apotentially applicable in biodiesel synthesis.Biodiesel production via transesterification of palm oil with methanol using solidoxide catalyst derived from waste shell of abalone was investigated. The shells werecalcined at different temperatures for3h. Formation of solid oxide i.e. CaO wasconfirmed at calcination temperature of900℃. The effect of the reactiontemperature, the molar ratio of methanol to oil, catalyst amount and catalystcalcinations temperature used for transesterification were studied to optimize thereaction conditions. Biodiesel yield was up to90.3%when transesterification wascarried out at65℃by employing12:1methanol to oil molar ratio and6.0wt%catalyst. The results showed that the Ca-based catalysts derived from shells showedgood reusability and had high potential to be used as biodiesel production catalystsWaste pig bone was used as a cost effective catalyst for the transesterification ofpalm oil. The catalyst was calcined at different temperatures to transform the CaO and1000℃was found to give the best yield of biodiesel. Under the optimal reactionconditions of15wt%of catalyst,1:18oil to methanol molar ratio,800rpm of stirringof reactants and at a temperature of65℃, the methyl ester conversion was86.7%and it was achieved in4h. Reusability of waste shell catalystwas also examined. Theresults indicated that the CaO catalysts derived from waste bones showed goodreusability and had high potential to be used as biodiesel production catalysts intransesterification of palm oil with methanol.From the results above, the Ca-based catalysts derived from eggshell (duckeggshell), mollusc shell (abalone shell), and bone (pig bone) were elucidated tobecome active in heterogeneous transesterification for biodiesel production. Thedescending order of the catalytic activity over the shell-derived catalysts was asfollows: eggshell> mollusc shell> bone. Among three raw materials, the catalystsynthesized from eggshell showed the highest Ca content and highest surface area,which could be the reasons of highest biodiesel yield.