EXHAUST EMISSION CONTROL DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an exhaust emission control device using and allowing an NOx storage and reduction type catalyst for removing NOx in exhaust gas of a gas engine heat pump using natural gas as a fuel to be regenerated at a low temperature of 500 to 600 deg.C when deteriorated by SOx. SOLUTION: The NOx storage and reduction type catalyst for storing NOx in combustion exhaust gas when an air-fuel ratio is under lean atmosphere and reducing absorbed NOx in combustion exhaust gas when an air-fuel ratio is under rich atmosphere is provided in an exhaust gas passage of an internal combustion engine. The NOx storage and reduction type catalyst contains NOx storing agent containing at least potassium element as a part of component. When it stores SOx in exhaust gas and its catalyst activity is reduced, a temperature is raised up to 500 to 600 deg.C under the presence of combustion exhaust gas in rich atmosphere, and the stored SOx is reduced and released to regenerate the catalyst.