Study On Soybean Biodiesel And Its Application In Diesel Engine

Biodiesel is consisted of the monoester which obtained through the chemical reaction of the animal fat or the vegetable oil. As an alternative, non-toxic, biodegradable and renewable diesel fuel, more and more attentions are paid to the Biodiesel. Many studies have shown that the properties of biodiesel are very close to diesel fuel. Therefore, biodiesel can be used directly in the diesel engines and does not need to change diesel engine's structure.This thesis introduces the manufacture process of soybean biodiesel which was manufactured through transesterification of soybean oil by methanol under the action of NaOH as catalyst. Through orthogonal analysis, the optimum conditions are obtained for the transesterification, that is, reaction temperature is 65℃, molar ratio of methanol to oil is 6:1, amount of NaOH is 1.3% and reaction time is 25 min. The yield of biodiesel is 92% under these conditions. Physical and chemical characteristics of a self-made biodiesel and diesel NO.0 were compared. The results indicate that cetane number, viscosity and density of biodiesel are larger than those of diesel. Sulfur content of biodiesel is much lower than that of diesel. Biodiesel contains about 10 percent of oxygen, but diesel contains no oxygen.The performance and emission characteristics of a sofim 8140.27 diesel engine fueled with NO.0 diesel and bio-diesel separately were studies. The result shows that the engine power and torque decrease for biodiesel fuel, and the NO_X emission decrease. Soot decreases greatly for biodiesel in full load. But in 13-step test, Soot decrease only on point 6 and 8,and almost not change on the other points.The fuel ecnomic and emission characteristics of the disel engine fueled with blend of NO.0 disel and biodiesel were tested with the different ratio in the thesis. The results show that the biodiesel and different blending ratios of biodiesel engines have the same tendency of power performance, fuel consumption and exhaust emissions in the load test. Soot greatly reduced under high load, and NO_X decreased.