Transformation Characteristics of Hydrogen-Donor Solvent Tetralin in the Process of Direct Coal Liquefaction

The aim of this study is to investigate the transformation of hydrogen-donor solvent tetralin in the direct liquefaction process of coal. Pure tetralin liquid as well as mixture of tetralin and Wucaiwan coal (WCW) were separately reacted under a liquefaction condition, and constituents of liquid product were analyzed by GC-MS. The results show that after the tetralin liquid reacts with high-pressure hydrogen, 90% of the reaction product is in liquid state, the gaseous products mainly include alkane gas and COx gas. When the reaction temperatures were set at 380 and 420 degrees C, respectively, the corresponding transformation rates of tetralin can be 34.72 and 52.74%. At 380 degrees C, the tetralin mainly plays a role of passing active hydrogen, while at 420 degrees C, it mainly occurs dehydrogenation transformation to provide active hydrogen, as well as generate naphthalene, methyl indan, and substituted benzene, etc. Taking tetralin as the hydrogen-donor solvent, the WCW was performed liquefaction reaction, and the obtained results show that the transformation rates of tetralin are 69.76 and 83.86% at liquefaction temperatures of 380 and 420 degrees C, respectively. Tetralin mainly occur to dehydrogenation transformation to generate naphthalene, followed by methyl indan, where contents order of main constituents of the liquefaction products were: naphthalene> tetralin > methyl indan.