The Effect Of Surfactants To The Conversion Of Coal And Coal-Derived Asphaltenes In Coal Liquefaction Process

Abstract

Due to the agglomeration of coal particles and coal-derived asphaltenes, conventional processes for coal liquefaction require its reactions under severe conditions. Even at a high temperature and a high hydrogen pressure, the yield of coal liquefaction is still not satisfactory. In this investigation, surfactant is introduced in the coal liquefaction process to reduce the agglomeration of the coal particles and coal-derived asphaltenes. Thus, the yield of coal liquefaction is improved significantly. In the surfactant screening test, six selected surfactants were examined at elevated temperatures separately in both coal/coal solvent systems. The viscosity of coal suspension and the suspended coal concentration are used as indicators to determine the performance of surfactants. The results show that surfactant calcium lignosulfonate has the best performance among selected surfactants which may be due to the increase of surface charges and double layer expansion. In the autoclave experiments, the suggested surfactant not only raises the yield of coal liquefaction but also changes the distribution of products. Under the same condition, almost twice the yield was obtained for both coal and lignite samples with the aid of surfactants.