PYROLYSIS OF COAL-TAR ASPHALTENE IN SUPERCRITICAL WATER

摘要

IntroductionThe increase in demand for light fuel oil and the price of crude oil leads to the further process heavy fuel. The annual output of coal tar in China is more than 6 million tons in 2006. The study shows that catalytic hydrogenation of coal tar could obtain light oil [1]. But in this process mass transport resistance is high and the deactivation of catalyst by coke deposition is serious. Recently, supercritical water (SCW) is attracting increased as a good solvent for chemical processes. It can complete miscible with gases and organic compounds [2], thus the pyrolysis fragments can dissolve well in SCW and the formation of char is suppressed. Experiments carried out in our laboratory have shown that the upgrading of coal tar in SCW is feasible, and the data suggest that asphaltene is the mainly active component during this process. Therefore, a further understanding of the reaction of asphaltene would provide additional insight into the upgrading mechanism of coal tar. In this study, the pyrolysis of coal-tar asphaltene in N2 and in SCW was investigated. The effect of reaction environment on asphaltene conversion were studied. The analysis of pyrolysis products was carried out and pyrolysis mechanism was discussed.