Research on prediction model of formation temperature of ammonium bisulfate in air preheater of coal-fired power plant

Abstract

Ammonium bisulfate (ABS) is a viscous compound produced by the escape NH3 in the NO reduction process and SO3 in the flue gas at a certain temperature, which can cause the ash corrosion of the air preheater in coal-fired power plants. Therefore, it is essential to study the formation temperature of ABS to prevent the deposition of ABS in air preheaters. In this paper, the SO3 reaction kinetic model is used to analyze the SO3 generation process from coal combustion to the selective catalytic reduction (SCR) exit stage, and the kinetic model of NO reduction is used to analyze the NH3 escape process. A prediction model for calculating the ABS formation temperature based on the S content in coal and NO reduction parameters of the SCR is proposed, solving the difficulty of measuring SO3 concentration and NH3 concentration in the previous calculation equation of ABS formation temperature. And the reliability of the model is verified by the actual data of the power plant. Then the influence of S content in coal, NH3/ NOx molar ratio, different NOx concentrations at SCR inlet, and NO removal efficiency on the formation temperature of ABS are analyzed.