Surface sulfidation modification of magnetospheres from fly ash for elemental mercury removal from coal combustion flue gas
Surface sulfidation modification of magnetospheres from fly ash for elemental mercury removal from coal combustion flue gas
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DOI：
10.1016/j.cej.2022.135212
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发表时间：
2022-02
影响因子：
15.1
通讯作者：
Feng Xin;Rihong Xiao;Yongchun Zhao;Junying Zhang
中科院分区：
文献类型：
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作者：
Feng Xin;Rihong Xiao;Yongchun Zhao;Junying Zhang
减少燃煤发电厂的元素汞（Hg 0）排放是一项巨大的挑战。在这项工作中，从飞灰中分离的磁球通过H2S作为有效的吸附剂进行改性（即，S-MS）。通过H2S的选择性催化氧化，在S-MS表面形成了对Hg 0具有高亲和力的元素硫。硫化温度对S-MS吸附Hg 0的影响很大，这与S-MS上硫物种的变化有关。当硫化温度为150 °C，硫化时间为30 min时，S-MS对Hg 0的吸附率可达80%以上。在50 ° C和75 °C下，S-MS对Hg 0的吸附性能最佳，说明S-MS可以通过在湿式电除尘器（WESP）系统的上游管道中喷射的方式来实现。气态Hg 0通过S-MS固定为稳定的硫化汞（HgS），由于存在丰富的硫物种，这是积极的结合Hg 0。废S-MS中汞在WESP出水中的浸出率低至1%，从而最大限度地减少了工业废物中汞的二次污染。成本分析表明，磁球吸附除汞技术在运行成本上明显优于商业活性炭喷射除汞技术。因此，S-MS具有吸附性能高、环境危害小、可回收等特点，在Hg 0封存方面具有巨大的潜力。
Reduction of elemental mercury (Hg0) emission from coal-fired power plants is an enormous challenge. In this work, magnetospheres separated from fly ash was modified through H2S as an efficient sorbent (i.e., S-MS) for Hg0. Elemental sulfur with high affinity towards Hg0was formed on the S-MS surface through selective catalytic oxidation of H2S. The sulfidation temperature played an important role in Hg0adsorption over S-MS, ascribing to the variation of sulfur species on S-MS. The S-MS exhibited above 80% Hg0adsorption efficiency with a sulfidation temperature of 150 °C for 30 min. The optimal Hg0adsorption performance was obtained at 50 and 75 °C, implying that the S-MS could be adopted by injecting into the duct upstream of wet electrostatic precipitator (WESP) system. The gaseous Hg0was immobilized by S-MS as stable mercury sulfide (HgS) owing to the presence of abundant sulfur species that is active for binding Hg0. The leaching ratio of mercury from spent S-MS in WESP effluent was as low as 1%, hence minimizing the secondary mercury pollution from the industrial waste. The cost analysis demonstrates that the mercury removal technology on the basis of magnetospheres adsorbents exhibited much superiority in operation cost compared with commercial activated carbon injection technology. Thus, the S-MS, with specific features, such as high Hg0adsorption performance, minimized environmental hazardous and recyclability, displayed great potential in Hg0sequestration.