石灰石-石膏法脱硫过程中浆液雾化夹带与细颗粒排放的关系

doi:10.11949/j.issn.0438-1157.20171000

摘要/Abstract

摘要：

脱硫浆液的雾化夹带是导致石灰石-石膏法脱硫过程中细颗粒物排放特征发生显著变化的主要原因。利用相位多普勒粒度分析仪（PDA）、电称低压冲击器（ELPI⁺）在线测试分析了脱硫浆液雾化、夹带特性及其与细颗粒物排放的关系。结果表明，石灰石-石膏法烟气脱硫过程中浆液雾化夹带可导致脱硫净烟气中含大量细小雾滴及亚微米级细颗粒，脱硫净烟气中雾滴粒径与喷嘴的雾化效果有关，主要集中在20 μm以下，雾滴含固量为脱硫浆液的20%～40%。脱硫操作参数如空塔气速、液气比和浆液浓度对脱硫净烟气中的雾滴夹带量存在显著影响，适当降低空塔气速、液气比及浆液浓度，优化喷淋工艺如增加喷淋层、合理布置脱硫喷嘴，能够有效抑制浆液夹带作用，进而降低脱硫净烟气中细颗粒物的排放浓度。

关键词: 石灰石-石膏法脱硫, 浆液雾化, 浆液夹带, 细颗粒物

Abstract:

Slurry droplets containing fine particles are entrained out of the scrubber in the process of the limestone-gypsum desulphurization, leading to significant impacts on the fine particle emission characteristics. The slurry atomization, entrainment characteristics of desulfurization slurry, and the relationship between fine particle emission and desulfurization slurry characteristics were on-line measured with the Phase Doppler Analyzer (PDA) system and the electrical low pressure impactor (ELPI⁺). The results show that large numbers of fine droplets and submicron solid particles exist in the flue gas after desulfurization, which attributes to the slurry entrainment during the desulfurization process. The emitted droplet sizes are related to the slurry atomization characteristics. They are mainly less than 20 μm and the solid content ratio of the emitted droplets and the slurry ranges from 20% to 40%. The operating parameters have significant effects on the amount of entrained slurry droplets such as the superficial gas velocity, the liquid gas ratio and the slurry concentration. With the decrease of these operating parameters and the spray optimization such as the increase of spray layers and the proper arrangement of the nozzles, the slurry entrainment is inhibited, resulting in the reduction of fine particle emissions.

Key words: limestone-gypsμm desulphurization, slurry atomization, droplet entrainment, fine particle

中图分类号:

侯大伟, 潘丹萍, 周心澄, 黄荣廷, 沈凯, 杨林军. 石灰石-石膏法脱硫过程中浆液雾化夹带与细颗粒排放的关系[J]. 化工学报, 2018, 69(4): 1714-1722.

HOU Dawei, PAN Danping, ZHOU Xincheng, HUANG Rongting, SHEN Kai, YANG Linjun. Relationship between fine particle emission and droplets during limestone-gypsum WFGD process[J]. CIESC Journal, 2018, 69(4): 1714-1722.

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