椰子油催化裂解提质生物油的燃烧性能评价

Combustion Performance Evaluation of Upgraded Bio-oil Derived From Coconut Oilby Catalytic Cracking

在温度450℃、氮气气氛下,将椰子油液相热解为椰子油热解油,然后进一步以CaO为催化剂进行气相催化裂解制得提质生物油。将柴油、提质生物油和棕榈生物柴油按不同比例混合得到柴油-提质生物油二元燃料和柴油-提质生物油-生物柴油三元燃料,采用柴油机测试混合燃料的燃油经济性和燃烧性能。结果表明:与椰子油热解油相比,提质生物油的酸值显著降低,低热值提升4.46%,含氧质量分数下降31%。柴油-提质生物油-生物柴油三元燃料在预喷阶段的放热率比柴油略有下降,而在主喷阶段的放热率有所升高,这与2段喷射期间的缸内压力变化相一致。与柴油-提质生物油二元燃料相比,生物柴油的加入使得三元燃料的十六烷值得到提升,滞燃期缩短,放热起始点提前,并且瞬时放热率峰值相位更加接近柴油。因此,柴油-提质生物油-生物柴油三元燃料在燃烧特性上更接近柴油,更适合作为理想的替代燃料。

The liquid-phase coconut oil was pyrolyzed in a nitrogen atmosphere at 450℃,based on which the upgraded bio-oil was further prepared by gas phase catalytic pyrolysis using CaO as catalyst.Diesel oil,refined bio-oil and palm biodiesel were mixed in different proportions to obtain diesel-upgraded bio-oil binary fuel and diesel-upgraded bio-oil-biodiesel terpolymer fuel.The fuel economy and combustion performance of the hybrid fuel were tested on diesel engine.The results show that compared with the pyrolysis oil from coconut oil,the acid value of the upgraded bio-oil is decreased significantly,the low calorific value is increased by 4.46%,and the oxygen content is decreased by 31%.The heat release rate of diesel-upgraded bio-oil-biodiesel ternary fuel is slightly lower than that of diesel in the pre-injection stage,and is increased in the main injection stage,which is consistent with the change of in-cylinder pressure during the two-stage injection.Compared with diesel-upgraded bio-oil binary fuel,the addition of biodiesel leads to an increase in the cetane value of terpolymer fuel,the ignition delay period is shortened,the heat release starting point is ahead of schedule,and the peak phase of instantaneous heat release rate is closer to that of diesel.Therefore,diesel-upgraded bio-oil-biodiesel ternary fuel is more similar to diesel fuel in terms of combustion characteristics,and is more suitable as an ideal alternative fuel.