The role of recycle oil in direct coal liquefaction process development

It has long been recognized that use of a recycle oil is a convenient and perhaps necessary feature of a practical direct coal liquefaction process. The recycle oil performs a number of important functions. It serves as a vehicle to convey coal into the liquefaction reactor and products from the reactor. It is a medium for mass and heat transfer among the solid, liquid, and gaseous components of the reactor inventory. It can act as a reactant or intermediate in the liquefaction process. Therefore, the nature of the recycle oil can have a determining effect on process configuration and performance, and the characterization of recycle oil composition and chemistry has been the subject of considerable interest. This paper discusses recycle oil characterization and its influence on the industrial development of coal liquefaction technology