详细调研了火电厂空预器发生堵塞的各种原因，认定空预器内生成硫酸氢铵是重要原因。进一步讨论了导致空预器入口SO₃浓度高的因素，发现硫酸氢铵的生成速率与SO₃浓度呈正比；提出了解决空预器堵塞最好的办法是降低空预器入口SO₃浓度，即在空预器入口或SCR出口等处喷射碳酸钠或注入其他碱性吸附剂来降低空预器入口SO₃浓度，指出此方法中核心技术是喷射系统。对于已经堵塞的空预器，提出采用化学清洗方法来提高清洗效果。

The causes of clogging happened in air preheater of thermal power plant are investigated in detail.It is confirmed that the formation of ammonium bisulfate in air preheater is an important cause for clogging.The factors causing high concentrations of SO₃ in air preheater inlet are discussed further.It is found that the formation rate of ammonium hydrogen sulfate is proportional to the concentration of SO₃.Thus,the best way to solve the air preheater clogging is to reduce SO₃ concentration in air preheater inlet,i.e.,sodium carbonate or other alkaline adsorbent is injected at the places such as the entrance of air preheater or the exit of SCR.The injection system is the core technology of this method.In addition,chemical cleaning method is proposed for the clogged air preheater.