Glycerol alkyl ether is a good fuel additive, which can improve fuel performance, increase cetane number, increase fluidity, reduce the composition and content of harmful substances in combustion tail gas, and be used as additives for diesel and biodiesel.The application of crude glycerol in this technology can not only utilize the by-product glycerol of biodiesel, but also obtain high value-added glycerol alkyl ether fuel additive. Among them, glycerol tert-butyl ether obtained by the reaction of glycerol with isobutene or tert-butyl alcohol is a promising additive. Adding glycerol tert-butyl ether to diesel fuel can significantly reduce the content of particulate matter, hydrocarbons and carbon monoxide in tail gas.KARINEN et al. investigated the etherification of crude glycerol with isobutene in liquid phase catalyzed by acidic ion exchange resin. It was found that the main reaction in the whole process was etherification. The main products were five kinds of ethers, and the side reaction was oligomerization of isobutene, resulting in hydrocarbons of C8-C16. Moreover, when the molar ratio of isobutene to glycerol was 3:1 and the reaction temperature was 80 C, the selectivity of the reaction was the best. The composition of ether products and the degree of etherification reaction can be controlled by changing reaction conditions.KIATKITTIPONG et al. used fluidized bed catalytic cracking (FCC) gasoline and glycerol as reactants and Amberlyst 16, Amberlyst 15, and beta-zeolite as catalysts to investigate the effect of etherification process on the performance of FCC gasoline. The results showed that the olefin content of etherified gasoline products decreased significantly and the octane number increased compared with the initial FCC gasoline. It was found that beta-zeolite had better catalytic effect and was more suitable as catalyst for etherification reaction when using beta-zeolite and mberlyst 16 as catalysts.
Glycerol can also be converted into fuel additives by acetylation and acetalization. RAHMAT etc studied the reaction process and specific characteristics of glycerol converted into fuel additives through etherification, acetylation and acetalization, and applied it to gasoline, biodiesel and diesel oil. The effects of the additives obtained from these reactions were investigated. PRADIMA et al. also summarized the different reaction processes (esterification, etherification, acetylation and acetalization) of glycerol to biofuel additives and related catalysts. It was found that when the fuel additives were mixed with diesel oil, the fuel additives could increase cetane number, improve low temperature fluidity, improve lubricity and reduce the harmful substances in exhaust gas. The effect of quantity. It can be seen that the utilization rate and application value of high value-added fuel additives can be improved by using crude glycerol. However, considering the influence of impurities in crude glycerol on the performance of final fuel, high efficient catalysts can be developed to increase the selectivity and yield of glycerol alkyl ethers. At the same time, unreacted components in crude glycerol can be separated with high efficiency separation and extraction process to avoid secondary pollution to fuel.
