Jiao Kunling, Chen Xiangyang, Bie Xuan, Liu Daokuan, Qiu Mingjie, Ma Shuangchen
Department of Environmental Science and Engineering, North China Electric Power University, Baoding, 071003, Hebei, China.
School of Energy and Environment, Inner Mongolia University of Science and Technology, Baotou, 014010, Inner Mongolia, China.
Sci Rep. 2021 May 17;11(1):10457. doi: 10.1038/s41598-021-90040-w.
When denitrification technology using NH or urea as the reducing agent is applied to remove NOx from the flue gas, ammonium bisulfate (ABS) by-product will also be generated in the flue gas. ABS has an impact on catalyst life span, denitrification efficiency etc., air preheater and its downstream thermal equipment also have a significant negative impact due to its plugging and corrosion. The requirement for NOx removal efficiency is improved by ultra-low emissions in China. However, wide-load denitrification makes the flue gas composition and temperature changing more complicated. Increasing ammonia injection can improve the NOx removal effect, but too much ammonia injection will lead to the formation of ABS and the increase of deposition risk, the contradiction between these two aspects is amplified by ultra-low emissions and wide-load denitrification in many plants. Coordinating NOx control and reducing the impact of ABS on equipment are issues that the industry needs to solve urgently. In recent years, extensive research on ABS had been carried out deeply, consequently, there has been a relatively in-deepth knowledge foundation for ABS formation, formation temperature, deposition temperature, dew point temperature, decomposition behavior, etc., but the existing researches are insufficient to support the problem of ABS under full load denitrification completely resolved. Therefore, some analysis and detection methods related to ABS are reviewed in this paper, and the impact of ABS on SCR, air preheater and other equipment and the existing research results on reducing the impact of ABS are summarized also. It is hoped that this review will provide a reference for the industry to solve the problems of ABS that hinder wide-load denitrification and affect ultra-low emissions.
当采用以氨（NH）或尿素作为还原剂的脱硝技术来去除烟气中的氮氧化物（NOx）时，烟气中还会生成副产物硫酸氢铵（ABS）。ABS会对催化剂寿命、脱硝效率等产生影响，其堵塞和腐蚀还会对空气预热器及其下游热力设备造成显著的负面影响。中国通过超低排放提高了对NOx去除效率的要求。然而，宽负荷脱硝使得烟气成分和温度变化更加复杂。增加氨的注入量可以提高NOx去除效果，但过多的氨注入会导致ABS的形成以及沉积风险的增加，在许多电厂中，超低排放和宽负荷脱硝加剧了这两方面的矛盾。协调NOx控制并降低ABS对设备的影响是行业亟待解决的问题。近年来，对ABS进行了广泛深入的研究，因此，对于ABS的形成、形成温度、沉积温度、露点温度、分解行为等方面已经有了较为深入的知识基础，但现有的研究尚不足以完全解决全负荷脱硝工况下的ABS问题。因此，本文综述了一些与ABS相关的分析和检测方法，并总结了ABS对选择性催化还原（SCR）、空气预热器等设备的影响以及降低ABS影响的现有研究成果。希望本综述能为行业解决阻碍宽负荷脱硝和影响超低排放的ABS问题提供参考。
