Patent ID: 6019952
Filing Date: 2000-02-01
Classification: B01D

Abstract:
A process for the oxidative removal of pollutants from an oxygen containing exhaust gas, comprising the steps:providing a first reactor comprising a plurality of serially arranged reaction zones, wherein each reaction zone contains an upstream catalyst; a downstream absorbent and a heater and providing a second reactor comprising a plurality of serially arranged reaction zones, wherein each reaction zone contains an upstream catalyst; a downstream absorbent and a heater;periodically alternating the following steps (a) and (b);(a) increasing the relative flow rate of the exhaust gas flowing into the first reactor so that a major portion of the exhaust gas flows into the first reactor and the pollutants within the exhaust gas are sorbed onto the absorbents, while, simultaneouslydecreasing the relative flow rate of the exhaust gas flowing into the second reactor so that a minor portion of the exhaust gas flows into the second reactor, and heating said second reactor to a catalyst light-off temperature, so that the pollutants within the exhaust gas and the pollutants released from the absorbents in this second reactor are catalytically destroyed in a downstream catalyst in a downstream reaction zone, and, after a predetermined period of time(b) decreasing the relative flow rate of the exhaust gas flowing into the first reactor so that a minor portion of the exhaust gas flows through the first reactor, and heating said first reactor to a catalyst light-off temperature, so that the pollutants within the exhaust gas and the pollutants released from the absorbents are catalytically destroyed in a downstream catalyst in a downstream reaction zone, while, simultaneouslyincreasing the relative flow rate of the exhaust gas flowing into the second reactor so that a major portion of the exhaust gas flows into the second reactor and the pollutants within the exhaust gas are sorbed by the absorbents.