Biofuel Product By Pyrolysis Of Oils And Fats With Molten Salt

The contradiction between supply and demand of petroleum resources and environmental pollution are going to exacerbate. The research of oil and fats transformation attracts more attention from people. In pyrolysis, the molten salts act as heat transfer medium, dispersing agent and catalyst, so it has a unique application prospect. In this paper, the ZnCl2-KCl which has a low melt point was used as the catalyst in soybean oil transformation. The main research contents and conclusions were as follows:(1) The pyrolysis behavior of molten salts in soybean oil pyrolysis was investigated using themogravimetric analysis (TG). The pyrolysis products were analyzed using Fourier transform infrared spectrometer (FTIR). The results showed that at the presence of water, the ZnCl2was transformed into ZnO by hydrolysis reaction at high temperature. Then ZnO combined with the carboxylic acid, and completed the decarboxylation reaction at last. The KC1directly participated in soybean oil pyrolysis and decarboxylation reaction.(2) The trait of molten salts in soybean oil pyrolysis was investigated in continuous stirred tank reactor (CSTR). The influences of pyrolysis conditions and CaO on the composition distribution and acid value of bio-oil were investigated. The appropriate pyrolysis temperature was430℃and feed rate was1.2g/min under no carry gas. The main compositions of bio-oil were alkenes (46.6%), alkanes (25.6%) and aromatics (16.1%). The other compounds which were oxygen-containing compounds like ketones and esters accounted for11.7%. The acid value was6.7mgKOH/g, much lower than that of the direct thermal pyrolysis (89.0mgKOH/g). It means that the molten salts have the ability of decarboxylation. When the basic catalyst of CaO at the mass proportion of5%was added into the molten salts, the acid value further decreased to3.9mgKOH/g.(3) In order to decrease the alkenes and oxygen compounds in bio-oil, hydrotreating process was carried out in a tubular reactor. The results showed that after hydrotreating using W-Ni catalyst, the alkenes and oxygen-containing compounds decreased to1.0%and0.7%, respectively. In order to decrease the heavy components in bio-oil, a tubular reactor was installed in the exit of the CSTR. The USY was added in the tubular reactor. The results showed that at the temperature of400℃, after USY catalytic pyrolysis, the carbon chain distributions of bio-oil were C6-8(32.0%), C9.14(36.8%) and C15-20(31.1%).(4) The molten salts pyrolysis of waste oil was investigated. The results showed that the appropriate temperature was405℃considering the bio-oil yield and acid value. At this point, the yield of bio-oil was58.9%. And the acid value was5.0mgKOH/g, much lower than that of the material (36.0mgKOH/g).