ABSTRACT

The composite solid absorbent was developed for simultaneous desulfurization and denitrification of low-temperature flue gas. The efficiency of this absorbent was confirmed by a pilot experiment in a coke oven. The surface and cross-section morphologies, elemental compositions and distributions, specific surface areas and pore size distributions, and phase compositions of fresh and used absorbents were measured to investigate the enhanced performance mechanism of absorbent and its removal mechanism for SO₂ and NO_x. The results showed that the absorbent had an efficient desulfurization and denitrification performance with about 99.9% SO₂ removal and more than 80% NO_x removal. The narrow pore distribution of absorbent produced more specific surface area as well as more active sites, which significantly enhanced the reactive activity of the absorbent greatly. Furthermore, the nanometer-scale channels and pores on the surface of absorbent promoted the diffusion of flue gas and the reaction of absorbent. SO₂ reacted with residual O₂ to produce SO₃, which formed CaSO₄ in the absorbent ultimately. NO reacted with residual O₂ and CO to form N₂ under the action of absorbent, which could be promoted at low temperature. For the CO-uncontained flue gas, NO will be removed by reacting with residual O₂ and the absorbent to produce Ca(NO₃)₂, which is beneficial for the solidified absorption of SO₂.

摘要

复合固体吸收剂是为低温烟气同时脱硫脱硝而开发的。在焦炉中进行的中试实验证实了这种吸收剂的效率。测量了新吸收剂和用过吸收剂的表面和横截面形态、元素组成和分布、比表面积和孔径分布以及相组成，以研究吸收剂的增强性能机制及其对 SO ₂和 NO _{x 的}去除机制。结果表明，该吸收剂具有高效脱硫脱硝性能，SO ₂去除率约99.9% ，NO _x去除率达80%以上。移动。吸收剂的窄孔分布产生了更大的比表面积和更多的活性位点，大大提高了吸收剂的反应活性。此外，吸收剂表面的纳米级通道和孔隙促进了烟气的扩散和吸收剂的反应。SO ₂与残留O反应₂产生SO ₃，其形成的CaSO ₄在吸收最终。NO在吸收剂的作用下与残留的O ₂和CO反应生成N ₂，可在低温下促进。对于不含 CO 的烟气，NO 将通过与残留的 O ₂反应去除和吸收剂生成Ca(NO ₃ ) ₂，有利于SO ₂的固化吸收。