Biodiesel production from waste oil feedstocks by solid acid catalysis

Biodiesel is a non-toxic and biodegradable substitute for petroleum-based diesel. However, it is impractical to use refined edible oils to produce biodiesel due to its high cost and priority for food products, especially in China, while waste oils with high free fatty acids (FFAs) can be considered as the raw materials. In the present work, a solid acid catalyst comprising SO₄²⁻/TiO₂–SiO₂ was prepared, characterized and studied for its activity for the production of biodiesel from several low cost feedstocks with high FFAs. The solid acid catalyst can be recycled, easily removed and can simultaneously catalyze esterification and transesterification. The influence of reaction parameters was studied, and the optimized reaction parameters are reaction temperature 200 °C, molar ratio of methanol to oil 9:1 and catalyst concentration 3 wt.%. The catalyst showed good stability. A continuous process for biodiesel production from cheap raw feedstocks was proposed, and a 10,000-tonnes/year biodiesel production demonstration plant has been built.     

Kinetic analysis of transesterification of waste pig fat in supercritical alcohols

The kinetic analysis method using non-isothermal technique was proposed to determine the kinetic parameters for the transesterification reaction of waste pig fat in supercritical alcohols. To investigate the transesterification of waste pig fat, the waste pig fat to alcohol ratio (w/w) was varied from 1:1.5 to 1:2.5 between the temperatures 220 and 290 °C at an interval of 10 °C in a 25 mL batch reactor. The products were analyzed by gas chromatography mass spectrometry. To verify the effectiveness of the proposed kinetic analysis method, the experimental values were compared with the values calculated using the kinetic parameters obtained from this work. It was found that the proposed kinetic analysis method gave reliable kinetic parameters for the transesterification of waste pig fat in supercritical alcohols. Further, it was found that the apparent activation energy for supercritical ethanol was lower than the value for supercritical methanol.     

Application of heterogeneous catalysis to biodiesel synthesis using microalgae oil

• Microalgae oil application for biodiesel synthesis is discussed. • Catalytic effectiveness of ferment preparations and chemical catalyst is disputed. • Application of heterogeneous catalysts for biodiesel synthesis is reviewed. • Possibilities of catalyst regeneration is shown. Recently, there is a growing interest in the use of microalga in various fields. Microalgae have properties such as rapid reproduction and high biomass accumulation, and under certain conditions, some are able to accumulate a large amount of oil. However, microalgae oil often contains more free fatty acids than the vegetable oil and is therefore unsuitable for biodiesel synthesis using alkaline catalysts. For this reason, some authors suggest the application of heterogeneous catalysis. A particular interest in the use of immobilized enzymes has developed. Other solid substances can also be used as heterogeneous catalysts are usually metal oxides, carbonates or zeolites. The use of these catalysts results in simpler biodiesel synthesis, especially purification processes, a cleaner end product and a less polluted environment. The molar ratio of alcohol to oil is lower during enzymatic transesterification, and more than 90% ester yield is obtained using a molar ratio of alcohol to oil of 3:1 to 4.5:1. The alcohols do not have a negative effect on the effectiveness of chemical catalysts, so it is possible to use alcohols in molar ratio from 4:1 to 12:1. The optimal temperature of enzymatic process is 30℃‒50℃. An ester yield of more than 95% was obtained in 12‒48 h. Using chemical catalysts, greater than a 95% yield of esters was obtained at higher temperatures in a shorter time. Material costs of enzymatic catalysis can be reduced by reusing the catalysts directly or after regeneration.     

The effect of cerium oxide additive on the performance and emission characteristics of a CI engine operated with rice bran biodiesel and its blends

In this study, the rice bran oil (RBO) has been converted into methyl ester with an aid of transesterification reaction. Chemically, transesterification means conversion of triglyceride molecule or a complex fatty acid into alcohol and ester by removing the glycerin and neutralizing the free fatty acids. The B20 blend samples [80% diesel + 20% biodiesel] were prepared for each methyl ester obtained from RBO and then the cerium oxide (CeO₂) nanoparticles were added to the each B20 blend samples at a dosage of 50 ppm and 100 ppm with an aid of ultrasonicator. Moreover, in the absence of any engine modifications, the performance and emission characteristics of those blend samples have been investigated from the experimentally measured values such as density, viscosity, cloud point, pour point, and calorific value while the engine performance was also analyzed through the parameters like exhaust gas temperature (EGT), brake specific fuel consumption (BSFC), brake thermal efficiency (BTE), exhaust emission of carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NOx). The experimental results reveal that the use of CeO₂ blended biodiesel in diesel engine has exhibited good improvement in performance characteristic and reduction in exhaust emissions.     

Optimization of novel pyrazolium ionic liquid catalysts for transesterification of bitter apple oil

In the present study, 4 different functionalized pyrazoliums based on sulfoalkyl-pyrazolium hydrogensulfate and alkylsulfo-alakylpyrazolium hydrogensulfate were explored to catalyze biodiesel production from bitter apple oil (BAO). The results demonstrated that a longer chains catalyst of 2-(4-sulfobutyl) pyrazolium hydrogensulfate (SBPHSO₄) exhibited the highest catalytic activity, which is attributed to its strong acidity. The highest yield of esters was up to 89.5% when the reaction was carried out under the conditions of 5.2 wt% of SBPHSO₄, molar ratio of methanol to BAO of 15:1, 170 °C, and 800 rpm for 6 h. These results demonstrated that ionic liquids offer a promising new type of pyrazolium catalyst for biodiesel production. The use of clean ionic liquids in preparing clean biodiesel could solve the drawbacks associated with using the old conventional catalysts and might be employed as an efficient catalyst for such relevance.