Iron-catalyzed cocurrent flow destruction and dechlorination of chlorobenzene during gasification

Iron-treated char was used in an attempt to catalyze chlorobenzene destruction in the ChemChar thermal waste gasification process. The contribution to the destruction removal efficiency (DRE) of chlorobenzene from gasification per se was increased from 99.75% when char was used in the gasifier bed to >99.99% when char treated with iron was used. This clearly satisfies the EPA requirement of 99.99% (4-nines) destruction. Furthermore, other operations in the total system including condensation of condensable matter from the gas stream, filtration of the dried gas over a char filter, and secondary combustion of the product gas contribute to additional removal of unreacted parent compound and byproducts, so that the DRE should easily be increased to 99.9999% (6-nines). The primary mechanism for chlorobenzene dechlorination was determined to involve the reduction of chlorobenzene by reaction with nascent hydrogen. Nascent hydrogen is produced through the water-gas shift reaction, which is believed to be catalyzed by FeO on the iron-treated char surface. Direct electron transfer from the reductive iron surface is also believed to contribute to dechlorination, however, to a lesser extent.