Jatropha Biodiesel Pilot Study

With the increasing depletion of oil resources, environmental pollution and the increase of the trend of vehicles with diesel, all countries in the world speed up the pace of development of replacement of fossil fuels. Under such circumstances, environmental protection and renewable biofuel technologies have emerged. Because of the nature of biodiesel and petrochemical diesel oil are very similar, so biodiesel can replace petrochemical diesel oil and turn to a new type of environmental clean renewable bio-liquid fuel, and has a great potential and broad market prospects. Biodiesel is also known as Fatty acid methyl ester. It is made of vegetable oil or animal fats and other renewable resources, which is the new clean fuels and can replace fossil fuels. It main comprises some ester compounds which are synthesized by palmitic acid, stearic acid, oleic acid, linoleic acid and methanol or ethanol. Those are long-chain saturated and unsaturated fatty acids. At present, most of the industrial techniques use acid or alkali catalyst to manufacture biodiesel. Although this method is much more mature, but this method claims raw materials higher and need longer reaction time. At the same time the latter process is more complex and catalyst life is limited and the products are separated difficultly with saponification occurred. So we need to seek new methods of preparation of biodiesel.Jatropha curcas.L is also known as Jatropha curcas, foul Tung, Tung oil tree, cream-tung, hibiscus trees, and so on. It is a Jatropha in Euphorbiaceae. Deciduous shrub or small tree is one of four major oil-bearing woody plants (Tallow, tea, nuts and small polycarpa) in China. Its seeds content high oil, the oil yielding rate was as high as more than 50%. Jatropha curcas.L seed oil which is toxic and cannot be eaten is mostly used in Chemical industry traditionally, such as the production of paints, hardening oil, soap and so on. At present, the main raw materials of domestic production of biodiesel are oil trench, edible waste oils. This is limiting large-scale development of biodiesel. That Jatropha curcas.L seed oil is as for raw materials of biodiesel enlarges the biodiesel source of raw materials and meets the large-scale development of biodiesel needs. At the same time this can be avoided the situation that development of biodiesel will compete with people for cooking oil.The author adopt two-step method of sub-critical water and supercritical methanol which does not add any catalyst to prepare biodiesel, with Jatropha curcas.L seed oil for raw material. The first step:the Jatropha curcas.L seed oil is hydrolysised into fatty acid in sub-critical water; The second step:The fatty acid is esterified into fatty acid methyl ester that is biodiesel in supercritical methanol. This paper has been detailed study of many factors which are effect on the preparation of biodiesel in the two step reaction, such as reaction temperature, reaction time, reaction pressure and the ratio of raw materials and other factors. The analysis of acid value is major, while it is calibrated by the ultra-high performance liquid chromatography. The best conditions that the Jatropha curcas.L seed oil hydrolysis in sub-critical water is temperature 290℃, oil-water volume ratio 1:3, reaction time 40min, which yields 98.9% of fatty acids. Reaction kinetics analysis shows that the reaction order of hydrolysis reaction is 0.7778; activation energy is 55.34kJ/mol, and kinetics equation is -dcA/dt=7254.96e55.34/RTcA0.7778.This article is firstly analysed Jatropha curcas.L seed oil fatty acid in supercritical methanol esterification with single-factor methods. According to the results of the test, I do orthogonal experiment for the reaction temperature, reaction time and fatty acids with the volume to Methanol factor in three factors and three levels, using L9 (34) orthogonal table. By range analysis and variance analysis, the most appropriate conditions of esterification are reaction temperature 290℃, reaction time 30min, volume ratio of to methanol 1:2. With the conditions of the test, the yields of fatty acids methyl ester is 99.02%. The reaction order of esterification is 1.45 and activation energy is 66.79 kJ/mol, reaction kinetics equation is-dcA/dt=5.56×105e66.79/RTcA1.45. Finally, Jatropha curcas.L and its biodiesel performance indicators are determined. In addition to the water content and acid value of the two indicators, all other indicators have reached national standards of China's biodiesel.