Improvement Cold Flow Properties Of Three Biodisel

Biodiesel is a green renewable energy. But the poor low temperature fluidity of biodisel making it easy crystallize at lower temperature and limiting its application. while cold flow improvers can reduce the freezing point of biodiesel and improve the cold flow properties of biodiesel. In this paper, different raw materials were used to synthesis biodiesel by transesterification. Cold flow improvers and winterization were used to improve the cold flow properties of biodiesel. Low temperature XRD, polarizing microscope and cryogenic differential scanning calorimetry were used to analysis crystallization in the course of the study.The main contents are as follows:(1) Using orthogonal experiment method to elect the optimal combination conditions of biodiesel preparation. The optimal reaction conditions of soybean biodiesel preparation was selected a molar methanol to oil ratio of 7:1 and the amount of 0.75% catalyst reaction 2 hours under 65℃; The optimal reaction conditions of waste cooking biodiesel preparation was selected a molar methanol to oil ratio of 7:1 and the amount of 0.5% catalyst reaction 2 hours under 65℃; The optimal reaction conditions of palm biodiesel preparation was selected a molar methanol to oil ratio of 8:1 and the amount of 0.75% catalyst reaction 2 hours under 65℃. The conversion rate of three raw material can reached 95% under optimum conditions optimization. Kinematic viscosity, closed flash point, acid value, water content, oxidation stability and cetane number of three biodisel meet ASTM D6751 and EN 14214 standards.(2) Using DSC, polarizing microscope and XRD analysis the effect of polyethylene-vinyl acetate (PEVA) on the cold flow properties of soybean biodiesel blend. The results showed that the cold filter plugging point of B60 can reduce to-7℃, the rate of crystallization of wax crystals slow down, crystal content decreased, solid-liquid phase-change decreased and the system more stable with addition of 1% PEVA.(3) Explored the blending effect and impact of mixed cold flow improving additive (EHMA, EAA and IOMA) on cold flow properties of biodiesel blends as well as the impact of mixed CFIs on other important fuel properties. Binary mixed CFIs (EAA-IOMA) performed better improvement on cold flow properties than others. The best PP and CFPP depression was observed in 2.5:10 (EAA-IOMA). The CFPP and PP are decreased by 11℃ and 12℃, respectively, with respect to the neat biodiesel.(4) Study of winterization impact on cold flow properties of palm biodiesel. After winterization, the CFPP and PP are decreased by 7℃ and 2℃, respectively, and other properties of palm biodiesel are within the standard range.