Formation of ammonia bisulfate in coal-fired power plant equipped with SCR reactors and the effect of reduced load operation

¹ AGH Akademia Górniczo - Hutnicza, al. Mickiewicza 30, 30-059 Kraków, Poland
² PGE Energia Ciepła S.A., ul. Złota 59, 00-120 Warszawa, Poland

mzyrkow@agh.edu.pl

Abstract

Coal fired power plant are still responsible for vast amount of electricity and heat production in Poland in 2019. Increasing number of units is equipped with SCR reactors in order to mitigate NOx emission. Older units have been designed to work in a base load operation· however increasing number of intermittent energy sources on the market· forces power plant owners to operate such units in reduced load for significant number of hours in a year. Most of parameters in coal-fired boiler would change in reduced load operation· particularly flue gas parameters. That would affect the formation of ammonia bisulfate (NH₄HSO₄) as well as operation of SCR reactors in the boiler. The NH₄HSO₄ formation is highly undesired as it can plug the catalyst or heating surfaces in the boiler. To investigate this phenomenon· the NH₄HSO₄ formation was comprehensively studied. Moreover· reduced load operation of boiler in a medium size CHP plant was simulated· using computer modelling tools. Obtained parameters were used to analyse· how different flue gas parameters affect NH₄HSO₄ formation and what consequences does it have for boiler operation. In particular, effect related with operation of SCR reactors equipped with V₂O₅-WO₃/TiO₂ catalyst was deeply studied.