微碱超/近临界法制备无甘油生物柴油动力学及其性能研究

Kinetics of trace KOH catalyzed glycerol-free biodiesel production under super/subcritical and its properties

对微碱超/近临界条件下,棕榈油与碳酸二甲酯(DMC)酯交换制备无甘油生物柴油的动力学进行了考察,并测试了无甘油生物柴油与0号柴油混合燃料的低温流动性能以及燃烧性能。结果表明:该反应在260~300℃的温度范围内呈拟一级反应,其反应活化能Ea为43.0 k J/mol,远低于常压碱催化的反应活化能79.1 k J/mol;当生物柴油的掺混比例低于5%时,其对0号柴油的冷滤点、倾点以及基本燃烧特性参数影响不大;通过低温结晶以及流变性能的测试,发现生物柴油中的饱和脂肪酸可以与石化柴油中的正构烷烃形成最低共熔物,从而延缓低温下燃料蜡晶的析出。

The transesterification kinetics of glycerol - free biodiesel from palm oil and dimethyl carbonate （DMC） under super/subcritical conditions with trace amount of KOH as catalyst was studied. Then the biodiesel was mixed with 0# diesel to produce the blend fuel, and the low temperature flow properties and combustion performance of the blend fuel were studied. The results showed that a pseudo first - order model was proposed at 260 -300 and the activation energy （Ea） was 43.0 kJ/mol ,which was far low- er than that of the alkine catalysis under normal pressure （79.1 k J/tool）. Besides, there was little difference of the cold filter plugging point, pour point and the basical combustion performance parameters of 0# diesel when the biodiesel account for less than 5% in the blend fuel. The low temperature crystallization and rheological properties test showed that the saturated fatty acids in biodiesel and n -alkanes in diesel could form the eutectic mixture, which could hinder the precipitation of fuel wax crystal.