Pyrolysis Of Triglycerides And Its Derivatives For Liquid Hydrocarbon Fuels In Molten Alkali

Under the double pressures of energy and environmental crisis, triglycerides have been concerned intensely for its renewability and the similar composition of fossil fuels. And the pyrolysis with high temperature of triglycerides is considered to be one of the most promising ways to produce liquid hydrocarbon fuels. Triglycerides derivatives, for example, fatty acid salts, have also been paid more and more attention by researchers.The pyrolysis of single saturated fatty acid salt——sodium stearate is conducted in a continuous bed reactor which is filled with molten alkali, and nitrogen is used as carrier gas. The appropriate pyrolysis temperature is425℃, gas flow rate is0.7L/min and feed rate is1.4g/min. Combined with gas and liquid composition of sodium stearate pyrolysis with molten alkali, the molten alkali not only is a heat carrier, but also participates in the reaction. The molten alkali promotes the decarboxylation and decarbonylation of sodium stearate, reacts with CO and CO2produced from pyrolysis, and also prompts reaction moving to the positive direction. Soaps produced by saponification reaction of soybean oil, tallow catalpa oil, lard oil and illegal cooking oil are cracked in molten sodium hydroxide system. The influence of different raw materials, deoxidization rate, composition and physical properties of pyrolysis liquid are investigated. It shows that the existence of a large number of saturated fatty acid salts in lard oil gains highest amount of alkane in liquid product, and because of lots linolenic acid which contains three unsaturated fatty acid in tallow catalpa oil, the highest content of aromatic hydrocarbon in liquid product. The physical and chemical properties of liquid product are more close to petroleum diesel.The pyrolysis of soybean oil mixed with glycerin is studied. The mixing ratio of soybean oil with glycerin and the different types of catalyst are investigated. Simultaneously, the pyrolysis characteristics of soybean oil and the mixture with glycerin are investigated by using TG-FTIR. When the mixing ratio is1:5, the content of alkane in liquid reaches the highest, from21.69%to26.11%compared with pyrolysis of soybean oil. And3%Pd/C-Al2O3catalyst shows better alkane yield. Reaction activation energy reduces nearly50%when the pyrolysis with molten alkali, it means that the addition of alkali prompting the pyrolysis. From FTIR, there is nearly no aldehyde, ketone, alcohol, and the most content in liquid is alkane. Therefore, it predicts that triglycerides convert into fatty acids firstly, and then fatty acids react with sodium hydroxide to generate the corresponding fatty acid salt, further decarboxylation or decarbonylation which takes off the carbonyl or carboxyl to generate hydrocarbon occurs.