SO3 Removal from Flue Gas by Using Na2SO3
SO3 Removal from Flue Gas by Using Na2SO3
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DOI：
10.1021/acs.energyfuels.0c00476
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发表时间：
2020-06-18
期刊：
影响因子：
5.3
通讯作者：
Yao, Qiang
中科院分区：
文献类型：
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作者：
He, Kejia;Song, Qiang;Yao, Qiang
燃煤电厂SO 3排放造成设备腐蚀和环境污染，可通过注入吸附剂来缓解。采用固定床反应器，在250-350 ℃温度范围内，模拟烟气条件下，研究了Na_2SO_3对SO_3的动态吸附。在SO 3吸附过程中，O-2对Na 2SO 3的氧化存在明显的竞争反应。SO_3吸附和O_2-氧化对Na_2SO_3的转化率均在反应初期迅速增加，然后缓慢增加。除250 ℃外，Na 2SO 3对SO 3的选择性也是先迅速增加后缓慢增加。后期在0.06 ~ 0.12之间。降低温度和增加SO_3浓度可提高SO_3的选择性。SO_3浓度的增加也促进了Na_2SO_3的氧化。孔结构分析表明，SO 3吸附增强后形成了多孔性更强的产物层，有利于O-2的扩散。SO2作为SO 3吸附的产物气体，抑制了Na 2SO 3与SO 3的正向反应。因此，增加SO2浓度削弱了SO 3吸附，降低了SO 3选择性。强烈的竞争反应大大降低了吸附剂的有效利用率，在设计deSO（3）工艺时应予以考虑。
SO3 emissions from coal-fired plants cause equipment corrosion and environmental pollution, which can be alleviated by adsorbent injection. The dynamic adsorption of SO3 by Na2SO3 was studied with a fixed-bed reactor at 250-350 degrees C under simulated flue gas. An obvious competitive reaction of Na2SO3 oxidation by O-2 was found during SO3 adsorption. The conversions of Na2SO3 by SO3 adsorption and by O-2 oxidation all rapidly increased in the initial stage and then slowly increased. The selectivity of SO3 adsorption by Na2SO3 also rapidly increased first and then slowly increased, except at 250 degrees C. It was between 0.06 and 0.12 in the later stage. Decreasing temperature and increasing SO3 concentration increased the SO3 selectivity. Na2SO3 oxidation was also promoted by the increasing SO3 concentration. Pore structure analysis showed that a more porous product layer was formed by the enhanced SO3 adsorption, facilitating the O-2 diffusion. As the product gas of SO3 adsorption, the presence of SO2 in the reactant gas suppressed the forward reaction of Na2SO3 and SO3. Thus, increasing SO2 concentrations weakened SO3 adsorption and decreased the SO3 selectivity. The strong competitive reactions greatly reduced the effective utilization of adsorbents, which should be considered during deSO(3) process design.