613 / 2019-01-20 22:54:04

Pyrolysis characteristics and kinetics of oleic acid based on tga

rubber seed oil；oleic acid；thermogravimetric infrared analysis； pyrolysis characteristics； kinetics

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Cheap and readily available plant oils and fats as a biomass, and at the same time a renewable resource, are receiving more and more attention in the production of chemical raw materials and fuels. The chemical nature of vegetable oils and fats is acylglycerols, which are mainly triacylglycerols. It is a complex mixture of several fatty acids. On the other hand, rubber trees have a long history of planting and application in yunnan. As a waste of the rubber industry, rubber seed oil is cheap and can be used to prepare chemical products, which not only realizes waste utilization, but also improves the added value of the rubber industry. Pyrolysis is one of the most widely studied methods for the conversion of triacylglycerol to hydrocarbons. Although the thermally catalyzed deoxidation of fatty acids and hydrothermal deoxidation of fatty acids have been well documented, there are few studies on the thermally catalyzed deoxidation and pyrolysis of free fatty acids. Therefore, for the complex mixture containing multiple fatty acids, including rubber seed oil, the study on the pyrolysis characteristics of a single component of the fatty acid can provide characteristic parameters for the kinetic study of the whole plant oil, so as to establish the kinetic model or criterion.
This experiment uses thermogravimetric infrared linkage technology (TG-DTG-FTIR) to treat a major monounsaturated free fatty acid oleic acid in rubber seed oil at different heating rates (10, 20, 30℃/ min). The pyrolysis characteristics were studied to obtain thermogravimetric dynamic analysis (TG-DTG) at different heating rates, changes in functional groups, and absorption bands and characteristic peaks of volatile products. The experimental results show that the oleic acid pyrolysis process can be divided into two stages: water volatilization stage (0-268 °C) and volatilization analysis stage (268-300 °C). As the heating rate increases, the initial pyrolysis temperature, pyrolysis termination temperature and maximum weight loss temperature in the pyrolysis process move to the high temperature region, and the maximum weight loss rate increases with the increase of the heating rate. At the same time, the pyrolysis activation energy and the pre-exponential factor have better compensation effects; and the pyrolysis reaction mechanism functions at different heating rates are different. It can be seen from the infrared spectrum that the characteristic peaks of CH4（Strong absorption band interval of 2650～3000 cm-1）, CO2（Near 670 cm-1 wave number）and CO (2000～2250 cm-1 weak absorption section)，appearing in the second stage of pyrolysis at different heating rates.