| 摘要 |
PURPOSE:To always maintain the prescribed denitration efficiency even if SOx concn. is fluctuated by remarkable load fluctuation by providing a pipeline of offgas and introducing offgas discharged from a sulfur recovery equipment to the inlet of a denitration tower. CONSTITUTION:In a two-stage treatment equipment for desulfurization and denitration consisting of a desulfurization tower 1, a denitration tower 2 and a sulfur recovery equipment 4 wherein activated carbon is circulated and ammonia is injected, the offgas pipelines 6, 7 are provided between the sulfur recovery equipment 4 and the inlet of the denitration tower 2. In case of treating low- concn. exhaust gas in an equipment designed in accordance with high-concn. SOx, SOx concn. in the inlet of the denitration tower is maintained in the range of 30-100ppm by opening a valve 8 and introducing offgas E wherein SOx remains to the inlet of the denitration tower 2 through the pipelines 6, 7. By such method, the prescribed denitration efficiency can be maintained without increasing leak of injected ammonia D even if exhaust gas of low-load SOx is treated. |
