CaSO_4在CO气氛下的平行竞争反应实验与模型研究

Experiments and model of the decomposition of CaSO_4 under CO atmosphere

采用热重等温实验研究了不同CO体积分数下CaSO4 的分解反应,利用红外光谱仪分析反应析出的气体成分,通过亚甲基蓝分光光度法测定固体残留物中CaS的质量分数。在CO气氛下,CaSO4 分解反应为平行竞争反应,反应生成了CaO和CaS。在0. 5%CO体积分数下,CaSO4 分解最终产物以CaO为主。在2%和4%CO体积分数下,反应初期分解产物以CaO为主,后期分解产物以CaS为主。分解反应最终产物中CaS质量分数随CO体积分数增加而升高,随温度升高而降低。推导出平行竞争反应模型,可以很好的描述CaSO4 的平行竞争反应。

The decomposition of CaSO4 is the key reason for the low efficiency of the desulphurization in grate furnace. In this paper, the decompostion of CaSO4 was investigated by means of a Metteler Toledo TGA with a infrared spectral analyzer for exhausted gas under isothermal condition. The mass fraction of CaS in final solid product was analyzed with the spectrophotometric measurement using ethylene blue. CaSO4 is converted to CaO and CaS simultaneously by parallel reactions under CO atmosphere. Under 0.5% CO atmosphere, CaSO4 is mainly converted to CaO. However, under 4% CO atmosphere CaSO4 is mainly converted to CaO in initial stage and CaS in latter stage. The mass fraction of CaS in final solid product increases with increasing the concentration of CO and decreases with increasing the temperature. The model of parrallel reactions could depict the decompositon of CaSO4 well under CO atmosphere.