| 摘要 |
<p>An exhaust gas purifying apparatus, including an NOx occlusion reduction catalyst (2) and a filter catalyst (3) arranged in series, is used, and the exhaust gas is allowed to flow from the NOx occlusion reduction catalyst (2) to the filter catalyst (3) in a normal flow process, and, in a recovery process for allowing exhaust gas added with a reducing agent to flow, the flow direction of the exhaust gas is reversed toward the NOx occlusion reduction catalyst (2) from the filter catalyst (3). Since the exhaust gas is heated by reaction heat of the filter catalyst (3), the NOx occlusion reduction catalyst (2) can recover from sulfur poisoning in the exhaust gas at a low temperature. Thereby, overheating of the filter catalyst (3) is prevented. Therefore, recovery from sulfur poisoning can be improved, and also deterioration and breakage of the filter catalyst can be prevented.</p> |
