In current development efforts, the conversion of coal resid to liquid fuels is mass-transfer-limited because the conversion catalyst particles are surrounded and fluidized by the slow moving fluidizing liquid. In turn, movement of the reacting molecules to and from the catalyst surface is severely limited. In this project, the reacting coal resid will be sprayed as a thin layer on fluidized solids, and fast moving hydrogen gas will be used as a dry fluidizing medium. In this arrangement, all the reacting resid will be in a very thin layer on the solid particles, and, therefore, the reacting distillate product will vaporize off the solid surface and be carried out of the reactor with the fluidizing hydrogen stream. This reactor will be the second stage of a two-stage liquefaction process. (The first, a thermal stage, converts coal to resid, and has been well developed.) Phase I will test this concept by impregnating small (100-1500 micron) ceramic particles with resid. The resid will contain a soluble molybdenum hydrogenation catalyst, which was developed for coal liquefaction. The impregnated ceramic particles will be injected into a reactor and fluidized by hydrogen at a conversion temperature (greater than 750ºF). Reaction products will be collected and analyzed. The kinetics of conversion and selectivity to liquid products will be compared with those of the current direct liquefaction process. Commercial Applications and Other Benefits as described by awardee: The technology should significantly increase the space-time yield of the second stage of a coal liquefaction process, thereby significantly reducing the size and cost of this reactor. This should reduce the cost of converting coal to transportation fuels by several dollars per barrel.
