Catalytic combustion type exhaust gas processing device and drying furnace for use in coating utilizing the same

Claim 2

A catalytic combustion-type processing device for exhaust gas discharged from a furnace for heating and drying a coating on an object and which exhaust gas contains volatile noxious/smelly components, said device comprising: a catalytic reactor housing comprising wall means defining a chamber having an inlet and an outlet for a gas stream following in a direction along a path; a first catalyst layer disposed in said chamber for dehydrogenating into aldehydes noxious/smelly components contained in a gas stream, said first catalyst layer comprising, in sequence along said path, a first sub-layer and a second sub-layer, each said sub-layer comprising at least one platinum group metal selected rom the group consisting of platinum, palladium, and mixtures thereof, said at least one platinum group metal being carried on a support; said support, in said first sub-layer being made of heat-resistant fibers; and a second catalyst layer disposed in said chamber downstream of said second sub-layer of said first catalyst layer, said second catalyst layer comprising a copper-cerium compound carried on a support, for oxidatively decomposing said aldehydes and thereby effectively decomposing noxious/smelly components.

Claim 3

The catalytic combustion-type exhaust gas processing device of claim 1, wherein: said support for said second catalyst layer is made of porous ceramic material.

Claim 4

The catalytic combustion-type exhaust gas-processing device of claim 1, wherein: said support for said second catalyst layer is made of heat resistant fibers.

Claim 5

The catalytic combustion-type exhaust gas-processing device of claim 1, wherein: said support for said second sub-layer of said first layer being one which is made of pellets, and said support for said second layer being made of porous ceramic material.

Claim 6

A furnace for heating and drying a coating on an object, comprising: an enclosure for receiving an object having a coating which is to be heated and dried; a recycle loop communicated both at a return duct end thereof and at a supply duct end thereof with said enclosure and incorporating a means for heating in said recycle loop a gas stream being recycled from and to said enclosure, and a catalytic combustion-type processing device for exhaust gas discharged from said furnace and which exhaust gas contains volatile noxious or smelly components, said device comprising: a catalytic combustion-type exhaust gas-processing device, comprising: a catalytic reactor housing comprising wall means defining a chamber having an inlet and an outlet for a gas stream flowing in a direction along a path; a first catalyst layer and a second catalyst layer, disposed in said chamber, for being sequentially contacted by said gas stream when flowing in said direction along said path; said first catalyst layer being disposed for dehydrogenating into aldehydes noxious or smelly components contained in said gas stream, said first catalyst layer comprising, in sequence along said path, a first sub-layer and a second sub-layer, each said sub-layer comprising at least one platinum group metal selected from the group consisting of platinum, palladium, and mixtures thereof, said at least one platinum group metal being carried on a support; said support, in said first sub-layer being made of heat resistant fibers; and said second catalyst layer being disposed for oxidatively decomposing said aldehydes and comprising a quantum of chemically active copper, and cerium, in the form of a copper-cerium compound, disposed on a second support; said inlet of said chamber being in communication via duct means with said enclosure and adapted to receive through said duct means a gas stream withdrawn from said chamber for passage along said path, whereby this gas stream is processed in said chamber and, after being processed, passes therefrom through said outlet of said chamber.

Claim 7

A furnace for heating and drying a coating on an object, comprising: an enclosure for receiving an object having a coating which is to be heated and dried; a recycle loop communicated both at a return duct end thereof and at a supply duct end thereof with said enclosure and incorporating a means for heating in said recycle loop a gas stream being recycled from and to said enclosure, and a catalytic combustion-type processing device for exhaust gas discharged from said furnace and which exhaust gas contains volatile noxious or smelly components, said device comprising: a catalytic combustion-type exhaust gas-processing device, comprising: a catalytic reactor housing comprising wall means defining a chamber having an inlet and an outlet for a gas stream flowing in a direction along a path; a first catalyst layer and a second catalyst layer, disposed in said chamber, for being sequentially contacted by said gas stream when flowing in said direction along said path; said first catalyst layer being disposed for dehydrogenating into aldehydes noxious or smelly components contained in said gas stream, said first catalyst layer comprising, in sequence along said path, a first sub-layer and a second sub-layer, each said sub-layer comprising at least one platinum group metal selected from the group consisting of platinum, palladium, and mixtures thereof, said at least one platinum group metal being carried on a support; said support, in said first sub-layer being made of heat resistant fibers; and said second catalyst layer being disposed for oxidatively decomposing said aldehydes and comprising a quantum of chemically active copper, and cerium, in the form of a copper-cerium compound, disposed on a second support; said inlet of said chamber being in communication via duct means with said enclosure and adapted to receive through said duct means a gas stream withdrawn from said chamber for passage along said path, whereby this gas stream is processed in said chamber and, after being processed, passes therefrom through said outlet of said chamber.

Claim 8

The furnace of claim 5, wherein: said heating means comprises a heat exchanger, a heater positioned and arranged to heat a gas stream in said duct means, a duct to atmosphere connected to said outlet of said chamber, and said recycle loop, intermediate said ends thereof, and said duct to atmosphere being disposed in indirect heat exchange relation through said heat exchanger.

Claim 9

The furnace of claim 5, wherein: said chamber of said catalytic reactor housing is interposed in said recycle loop, intermediate said ends of said recycle loop, with a corresponding part of said recycle loop providing a portion of said duct means; and said heating means comprises a heater interposed in said recycle loop, intermediate said chamber of said catalytic reactor, and said return duct end of said recycle loop.

Claim 10

The furnace of claim 5, wherein: said heating means comprises a heater for heating a gas stream in said duct means, and a duct connecting said outlet of said chamber with said recycle loop, intermediate said ends thereof.