Research On Coupling Relationship Between Low Temperature Fluidity And Oxidation Stability Of Biodiesel

With the rapid economic development and fossil fuel depletion and environmental degradation,the developed and developing countries have been confronted with an energy crisis.As an alternative of diesel,biodiesel has attracted world wide attention because it’s environmentally friendly and renewable.In recent years,more and more countries focus on the quality of biodiesel.It shows that the quality of biodiesel is an important factor,which restricts the use of biodiesel.Low temperature fluidity and oxidation stability are very important properties of biodiesel,which primarily affects the use in diesel engine.This thesis mainly completes as following:(1)Research on low temperature fluidity and oxidation stability of biodieselAdding cold flow improver and 0 # diesel into biodiesel,the impact of cold flow improver and the blending ratio of biodiesel on cold flow properties was analysed,it was found that cold filter plugging point of biodiesel blending fuel(B10,B20,B50)would increase at first and drop after with the increasing addition amount of cold flow improver,a low proportion(B5)with 0 # diesel could effectively reduce cold filter plugging point of biodiesel,but with increasing proportion of biodiesel added in 0 # diesel,cold filter plugging point was increased;adding antioxidants and 0 # diesel to biodiesel,the impact of antioxidants and blending ratio on the oxidation stability of biodiesel was analysed,it was found that adding a few amount(0.1%)of antioxidants can significantly improve the oxidation stability of biodiesel,the effects on biodiesel are quite different,at a low percentage of biodiesel(B10)with 0 # diesel can effectively improve the oxidation stability,along with the 0 # diesel blending ratio increasing,the oxidation stability of biodiesel became worse.(2)Influence factors of cold flow properties and oxidation stability coupling relationship of biodieselBy researching 10 kinds of composition of fatty acid methyl ester,the relations between cold filter plugging point and oxidation induction period was analysed,the ratio of the saturated fatty acid methyl esters,the monounsaturated fats and polyunsaturated fatty acid methyl ester would impact cold flow properties and oxidation stability coupled relationships of biodiesel,it was found that according to the requirements of biodiesel cold flow properties and oxidation stability,generally the consist of fatty acid methyl esters need a small amount of saturated fatty acids(<20%),more monounsaturated fatty acids(> 20%)and a certain amount of polyunsaturated fatty acids(<70%).(3)Diesel engine bench test to evaluate the feasibility of the improvementsThrough deploying the composition of fatty acid methyl esters to obtain biodiesel blending fuel,the emissions and fuel economy of biodiesel blending fuel were tested in a diesel engine,it was found that under certain circumstances of the engine output power,under low load,H20,H10,(H60WC40)10,W10 fuel consumption were lower than 0 # diesel,under load and full load,fuel consumption of biodiesel blending fuel were higher than 0 # diesel,and a larger increase in the medium load.NOX,HC,CO,CO2 emissions of biodiesel blending fuel were different in conditions.