Retrogressive reactions in catalytic coal liquefaction using dispersed MoS2

Abstract

Publisher Summary This chapter discusses how retrogressive reactions occur in catalytic liquefaction using dispersed Mo sulfide catalyst. Retrogressive reactions occur in coal liquefaction at 425–450° C in 25 mL reactors, even in the presence of dispersed Mo sulfide catalyst. By using H-donor solvent in catalytic runs at higher temperatures, the retrogressive reactions can be mitigated. Two approaches can be considered for improving the balance between thermal fragmentation(TF) and hydrogen available (HD): (1) modifying the rate of coal fragmentation at high temperatures by incorporating low-temperature coal pretreatment, temperature-staging, temperature-programming, and catalytic pretreatments and (2) increasing the hydrogen transfer capacity by using H-donor and hydrogen shuttler, in combination with hydrogenation catalyst under high pressure of hydrogen.