熟石灰在脱除含氯尾气过程中的失活热力学研究

Thermodynamic Study of the Deactivation of Slaked Lime in the Process of Chlorine-containing Tail Gas Removal

熟石灰在脱除含氯尾气过程中会因杂质气体的存在发生失活反应。使用HSC Chemistry热力学数据库对熟石灰(Ca(OH)_(2))的失活热力学进行分析计算,分析了Ca(OH)_(2)在100~1000℃的温度范围内可能存在的热力学反应,并且比较了各化学反应的化学平衡常数。结果表明,在吸附反应的条件下,Ca(OH)_(2)对HCl的反应能力较强;Ca(OH)_(2)与烟气组分(SO_(2)、NO、CO_(2)、O_(2)、H_(2)O)共存时均能引起Ca(OH)_(2)的失活,其中,NO对Ca(OH)_(2)的失活影响最大,最易生成的失活产物为CaCl_(2)和Ca(NO_(3))_(2),增加反应温度可以抑制失活反应的发生。

Deactivation reactions of slaked lime occur in the process of chlorine-containing tail gas removal due to the presence of impurity gases.The deactivation thermodynamics of slaked lime(Ca(OH)_(2))was analyzed and calculated using the HSC Chemistry thermodynamic database.The possible thermodynamic reactions of Ca(OH)_(2)in the temperature range of 100~1000℃were analyzed and the chemical equilibrium constants of each chemical reaction were compared.The results showed that under the condition of adsorption reaction,Ca(OH)_(2)has a strong reaction ability to HCl;the coexistence of Ca(OH)_(2)with flue gas components(SO_(2),NO,CO_(2),O_(2),H_(2)O)can all cause the deactivation of Ca(OH)_(2),among which,NO has the greatest influence on the deactivation of Ca(OH)_(2),and the most easily generated deactivation products are CaCl_(2)and Ca(NO_(3))_(2).Increasing the reaction temperature can inhibit the deactivation reaction.