Lu P.,Jiangnan Environmental Technology Inc. |
Zhang K.,Jiangnan Environmental Technology Inc.
Sulphur 2016 32nd International Conference and Exhibition | Year: 2016
An ammonia-based desulfurization process, in which ammonia is used as the desulfurization absorbent to react with SO2, removes SO2 from SO2-containing streams such as sulfur recovery unit (SRU) tail gas and produces ammonium sulfate fertilizer by-product without generating any waste water or solid waste. The patented Efficient Ammonia Desulfurization (EADS) technology offered by Jiangnan Environmental Technology (JET) can achieve SO2 emissions as low as 35 mg/Nm3 (10 ppmv), which meets today's most stringent environmental regulations with much lower capital and operating costs compared to the traditional tail gas treatment technologies. The EADS technology has been applied to Datang International Hexigten's Coal Gasification Unit. The H2S-containing process gas is treated with the conventional SRU followed by an ammonia absorber as the tail gas treatment unit (TGTU). The ammonium sulfate solution generated from the ammonia-based SRU tail gas desulfurization unit is combined with the ammonium sulfate solution generated from an ammonia-based boiler FGD unit, and is further processed to produce fertilizer-grade ammonium sulfate. The desulfurization absorbent used is 20% aqueous ammonia, which is recovered from the waste water stream generated from the gasifier. The SO2 emission at the outlet of the ammonia absorber is less than 100 mg/Nm3 (35 ppmv). The production of sellable ammonium sulfate using the ammonia recovered from the waste stream produces a second revenue stream and makes the process unique and attractive both environmentally and economically.