脱除SO2并回收硫磺的冶炼烟气处理工艺

介绍用甲烷(天然气)直接还原技术使冶炼烟气中SO2生成元素硫的工艺研究。SO2直接还原法分2 步:在高温下用甲烷将部分SO2还原成S和H2S,然后未反应的SO2和H2S发生Claus转化反应生成S。研究发现, 在工业装置中还原反应器宜采用分批甲烷法进料,以避免烟灰的生成;另需严格控制各种物料的相对比例,以确保位于Claus转化系列的硫冷凝器排出的尾气中的H2S／SO2为2,从而优化工艺性能。另外试验发现,在不同的停留时间下,SO2转化率与反应温度的关系曲线变化趋势是相反的,因此必须根据具体的现场条件选择停留时间。Siirtec Nigi公司和Albera硫研究有限责任公司联合开发了一种CH4／SO2还原／Claus／HCRTM工艺,其总硫回收率可达到99％以上。试验确定了一组有价值的化学工程数据,可用于该工艺的工业装置设计。

Smelter Off-Gas Treatment for SO2 Removal and Sulphur Recovery

Technological research for direct reduction of SO2 to elemental sulphur using methane (natural gas) as reduction agent is described. Sulphur production by direct reduction of SO2 consisted of two steps; reduction of part of SO2 with methane to H2S and sulphur followed by the Claus conversion of the unreacted SO2 with H2S to sulphur. The tests indicated that split methane strategy remained the most viable route to eliminate soot formation in an industrial plant. The relative ratios of various materials had to be controlled carefully to assure that an H2S/SO2 ratio of 2 was achieved in the tail gas issuing from sulphur condenser of Claus converter train for optimum process performance. The tests also indicated that, the shapes of the curves relevant to the SO2 conversion versus the operating temperature were reversed at different residence time, so the selection of the residence time had to be done very carefully, taking into account the specific field condition. The collaborative efforts of Siirtec Nigi and Alberta Sulphur Research Ltd aimed at developing a combined SO2/CH4 reduction/Claus/HCR process to achieve overall sulfur recovery of >99%, had resulted in the definition of a set of valuable chemical engineering data which could be used for the implementation of the process.