CATALYTIC COMBUSTION OF POLYCHLORINATED-BIPHENYLS IN MONOLITH REACTORS

The catalytic combustion of Aroclor 1242 (consisting of polychlorinate d biphenyls, PCBs) was studied using a single channel monolith reactor of 15 mm i.d. and lengths varying from 150 to 310 mm. Experiments wer e performed at gas hourly space velocities in the range of 6 x 10(3) t o 13 x 10(3 h-1 and inlet temperatures > 740 K. The catalyst used was chromia on an alumina support for ceramic substrates, and chromia on z irconia for the metal inserts; catalyst coating techniques are also de scribed. Reaction experiments were performed with varying internal des igns for the monolith reactor, that is, with and without the use of ca talyst coated inserts. A technique of coating the metal insert with a ceramic substrate prior to catalyst loading is described. The catalyst coated insert substantially enhanced the performance of the reactor. Reaction experiments in a segmented multichannel catalytic monolith sh owed that fractional conversions of PCBs in excess of 0.99 can be achi eved. A single channel annular flow model has also been used as a diag nostic tool to interpret the experimental results.