This chapter describes the flash copyrolysis of coal retaining depolymerized polyethylene as radical donor. Flash pyrolysis is an attractive coal conversion process for the production of useful chemicals, such as benzene and naphthalane derivatives. These light aromatics are generated by the vapor-phase secondary pyrolysis of tar that is produced in the primary pyrolysis stage. To increase the yield of the tar that is the precursor of light aromatics, decomposition of the macromolecular network of coal is enhanced in the primary pyrolysis. Rapid donation of hydrogen and hydrocarbon radicals to fragment radicals of coal molecules is essential both to promote tar evolution and to suppress char formation. Polypropylene and polyethylene coated on the surface of a brown coal increased the tar yield by 5–12 wt% on the daf-coal basis by donating hydrogen and hydrocarbon radicals under atmospheric pressure. The promotion of tar formation is strongly dependent on the contact between coal and polyolefin. The swollen coals are physically incorporated with depolymerized polyethylene (DPE) and are subjected to flash pyrolysis with a Curie point pyrolyzer and an entrained-flow pyrolyzer.
All Science Journal Classification (ASJC) codes