Catalytic purification reactor

Reactor consists of vertical cylindrical housing with gas inlet-outlet nozzles, conical cover and flat bottom. Inner space is divided by blind horizontal partition into two chambers - upper and lower, connected to each other by central support tube-mixer with internal turbulising partitions. In each chamber on the grates there is a layer of intertert packing (for example, Rashig rings) and on top of the packing - a layer of catalyst. On top of each chamber, above the catalyst bed, there are detachable packages of electric heaters in the form of TENs located in cassettes, in each of which, at the bottom and at the end, there are openings for gas passage, the rest section of the reactor is covered with a blind partition. Cover in upper chamber is shielded from heat loss by additional partition. For selective catalytic cleaning of gases in the middle of the mixer there installed is a gas sprayer header with holes, which is connected by pipeline to a union for supply of reducing agent (ammonia, ammonia water). The achieved technical result of using the whole set of essential features described above consists in reduction of metal consumption and cost of the reactor, reduction of heat loss into the environment and, as a result, reduction of the amount of heat supplied to the reaction zone.

Before start-up the layers of the catalyst and the part of an inert nozzle adjoining to them are heated to 280-380os by supply of atmospheric air alternately via unions in camera I, then supply flue gas with a temperature 60-80os. The cold cleaning gas passing through the inert packing bed and the catalyst bed in chamber I is heated as in the regenerative heat exchanger to a temperature at which the selective reduction reaction proceeds at a sufficiently high rate at 280-380C. Simultaneously, a reducing agent is fed to the nitrogen oxide-containing gas stream through the spray header; which is mixed in the mixer downstream, then through the heater packs and the windows the reaction mixture is further mixed and introduced into chamber II onto the catalyst bed; where nitrogen oxides are finally reduced, the heat of the reacted mixture is absorbed in an inert nozzle; then the mixture flows out of the apparatus into atmosphere through the side connector.

After a certain period of time, the direction of movement of the gas stream to be purified is reversed (second half-cycle) and the reaction mixture travels the same path but in the opposite direction. After a predetermined period of time, the cold gas supply direction is reversed again, thereby continuously operating the reactor in a so-called non-stationary mode. The amount of heat introduced into the reaction mixture is controlled by the heaters depending on the concentration of impurities in the gas to be cleaned. The contact apparatus is designed for selective purification of gases from nitrogen oxides, from organic impurities, etc.