Counterflow catalytic device

Abstract

A catalytic oxidizer having a combined central catalyst chamber and a spiral heat exchanger for treatment of air hydrocarbon vapor mixture including an outer shell of circular cross section having a tangentially directed longitudinal inlet aperture, a parallel exhaust aperture, an end cover plate and having a catalytic chamber centrally and coaxially positioned in the outer shell including an inlet port and an outlet port, the catalytic chamber including an upstream plenum, a catalyst core member and a downstream plenum, having perforated partitions for separating the catalyst core member from the inlet plenum and the exhaust plenum, and a coaxial spiral plate heat exchanger surrounding the catalytic chamber including a spiral inlet passage formed by coiled plates connected at one end to the inlet aperture and at the other end to an outlet associated with the inlet plenum defining a first heat exchange region, the coiled plates being spaced apart to create an intermediate spiral exhaust passage, the heat exchanger being sealed at opposite ends defining a second heat exchange region; and including a by-pass device for detecting and venting excess pressure in the catalyst chamber; wherein inlet flow passes through the spiral inlet passage inwardly and an opposed exhaust flow passes outwardly in the adjacent spiral exhaust passage, the exhaust, being heated by catalytic combustion in the core, heats the inlet flow.