FCC催化剂焙烧尾气中HCl的吸收、提浓与综合利用

Absorption,Concentration and Comprehensive Utilization of HCl in Roasting Tail Gas of FCC Catalyst

FCC(催化裂化)催化剂在制备过程中,为了调节反应的pH值,反应过程中加入了一定量的盐酸,其中氯离子绝大部分在焙烧过程中以HCl气体的形式被除去或排放到空气中。提出了将这部分Cl-以盐酸的形式重新回收,直到产品中氯离子含量符合工艺要求。提高盐酸的浓度,将HCl变废为宝,降低废气的治理成本。针对如何有效除去并吸收尾气中的HCl气体通过优化原有系统,改善吸收效果,在原有的一级急冷+二级吸收的系统上,研发了一级急冷+三级吸收的尾气处理系统,通过新系统使催化裂化催化剂焙烧高温尾气除尘后出口粉尘含量≤60 mg/Nm^3,最终尾气粉尘含量≤5 mg/Nm^3,盐酸含量≤5 mg/Nm^3,尾气吸收液中氯离子的回用率达到90%;回收盐酸浓度≥25%(wt)。

During the preparation of FCC catalyst, in order to adjust the pH of the reaction, a certain amount of hydrochloric acid is added in the reaction, most of the chloride ions in which are removed or discharged as HCl gas during the roasting process. In this article, it’s innovatively proposed that part of the CL-should be recovered in the form of hydrochloric acid until the chlorine ion content in the product meets the process requirements. Increasing the concentration of hydrochloric acid can turn waste HCl into useful material to reduce the cost of waste gas treatment. In view of how to effectively remove and absorb the HCl gas in the exhaust gas, the absorption effect was improved by optimizing the original system. Based on the primary quenching + secondary absorption system, a primary quenching+ tertiary absorption tail gas treatment technology was developed. The technology can make catalytic cracking catalyst roasting high-temperature tail gas dust content be less than 60 mg/Nm^3, final exhaust dust content is ≤5 mg/Nm^3,hydrochloric acid content is ≤5 mg/Nm^3, tail gas absorption liquid chlorine ion reuse rate reaches 90%, recovered hydrochloric acid concentration is ≥ 25%(wt).