Study On Preparation Of Biodiesel Oil From Tong Oil

Increasing environmental awareness and depletion of energy resources stimulate people to develop renewable fuels which are environmentally friendly. The research resulted in an alternative fule called biodiesel, which , generally, consisted of alkyl esters of natural oils or fats, and can be preparaed by transesterification. The main advantages of biodiesel are the renewability, the better quality exhaust gas emissions, the biodegradability and not contributing to a net rise in the level of carbon dioxide in the atmosphere.The aim of this research is to study the preparation method of biodiesel fules from cottonseed oil and Tung oil, and investigate the possibility of transforming Tung oil to biodiesel. Tung oil is rich in China and its annual output is about 75% of worldwide Tung oil output, therefore there is a resource preponderance in developing biodiesel from Tung oil in China.In this paper, Firstly, we studied the main fatty acid compositions and properties of cottonseed oil, Tung oil , rapeseed oil, and determined the acid value, density, soapnification value, peroxidate value and the average molecular weight. The transesterification reaction is manily affected by four factors:molar ratio of oil to methanol, catalyst dosage, reaction temperature and reaction time. Subsequently, the prepartion methods of the former two biodiesels by transesterication and its optimum conditions were investigated by orthogonal test. Finally, the properties of biodiesel fules from the Tung oil and cotton oil were analyzed, and compared with that of fossil diesel.The results showed that the average molecular weight of Tung oil, cotton oil and rapeseed oil were 927.32, 988.24, 933.96, the densities were 0.9375, 0.9182, 0.9141 g/mL, the soapnification value were 185.8100, 170.5000, 182.2000 mg/g, the peroxidate value were 0.1200, 0.0795, 0.0740 g/100g, resp.. The main compositions of Tung oil, cotton oil and rapeseed oil wereα-elaeostearic acid, octadecadienoic acid and octadecenoic acid, resp. . For three plants, the amounts of fatty acids with 16-22 carbon atom number accounts for about 97% of total fatty acids, of which the percent of unsaturated fatty acids was about 94%. The important factors affecting transesterification are the molar ratio of oil to alcohol, the amount of catalyst, reaction temperature and reaction time. By the orthogonal test of the Tung oil transesterification reaction, the optimum conditions for biodiesel preparation were:molar ratio of Tung oil to methanol 6∶1, 1.0% w/w(oil) of catalysts, reaction time 20 min, reaction temperature 30℃with the average yield of 91.1% and 0.59 RSD. However, the optimum reaction conditions for magnifying test were: molar ratio of oil to methanol 6∶1, 0.8 % w/w(oil) of catalysts, reaction time 40 min, reaction temperature 40℃with the average yield of about 88.0%. In addition, The optimum conditions for biodiesel preparation from cottonseed oil was obtained with molar ratio of oil to methanol 7 : 1, 1.1% w/w(oil) of catalysts, reaction tempreture 35℃, reaction time 30 min with 98.9% in yield.The performance analyses showed that the physical and chemical characteristics of of above two biodiesels were very closer to Number 0 diesel fuel, which made them a good substitutes for Diesel fuel.But their acid value, density and kinematic viscosity are a bit higher than Number 0 diesel fuel.