柴油-生物质油乳化燃料最佳HLB值及理化性质研究

采用超声波乳化法制备柴油-生物质油乳化燃料，并研究了乳化燃料所需乳化剂的最佳亲水亲油平衡（HLB）值以及乳化条件对乳化燃料稳定性的影响，测定了乳化燃料的密度、黏度、闭口闪点、烟点、凝点和总热值等理化性质。结果表明，柴油-生物质油乳化燃料乳化剂的最佳HLB值为5.5~6.2；当乳化温度为50℃~60℃、单位容积输入功为180J/mL~300J/mL时，乳化燃料的稳定性最好；乳化燃料的密度、黏度、闪点和烟点随生物质油比例的增加而增大，而凝点和总热值则随生物质油比例的增加而降低。

Study on optimum HLB value and physicochemical properties of diesel and bio-oil emulsions

Bio-oil produced from biomass by fast pyrolysis is mainly composed of oxygenated organics and contains high content of water, which makes it unsuitable for direct use as fuel. By developing emulsions from diesel and bio-oil, however, the bio-oil can then be used in compression ignition engines. In this work, the emulsions from diesel and bio-oil are produced by using ultrasonic emulsification method. The physicochemical properties of the emulsions were measured, including density, viscosity, flash point, smoke point, freezing point, and gross heating value. The optimum hydrophilic and lipophilic balance (HLB) value of the emulsifier and the influence of emulsification conditions on the emulsion stability were investigated. The results show that the optimum HLB value of the emulsifier for the emulsification of diesel and bio-oil is about 5.5～6.2;the most stable emulsions are then obtained when the emulsification is conducted at 50℃～60℃ and with the input work of 180J/mL～300J/mL. With the increase of bio-oil content in the emulsions, the density, viscosity, flash point and smoke point of the emulsions are increased, while their freezing point and gross heating value are decreased.