Process concept for a zero-emission route to clean middle-distillate fuels from coal
A novel process configuration has been developed for producing clean middle-distillate fuels from coal with minimal emissions. The EMS Energy Institute at Penn State University has developed and tested a solvent extraction process for making liquids from bituminous coals, and has shown the successful use of these fuels in small jet engines, a diesel-engine pickup truck, and a solid oxide fuel cell. The core of the process involves extracting coals with light cycle oil, a refinery byproduct, separating the residual solids, hydrotreating the liquid to remove sulfur, hydrogenating to eliminate aromatic compounds, and finally distilling to obtain the fuel products, which represent the majority of the liquid yield. The optimum yield of the raw extract, after three stages of extraction, is as high as 75%. The recovery of middle-distillate fuels from the hydrotreated and hydrogenated extract is up to 80%. A solvent stream would be recycled back to the front...