Coal-fueled power plants use selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR) technologies to reduce emissions of nitrogen oxides. During operation of SCRs and SNCRs, unreacted ammonia reagent can cause fouling of air heaters and other downstream components of power plant units and yield excess amounts of ammonia that deposit on coal ash left over after combustion. This condition, known as “ammonia slip,” creates maintenance and operational issues for power plants, including complications for handling the coal ash for disposal and beneficial use.
Among these complications are:
When fly ash with excess amounts of ammonia is wetted under alkaline conditions, ammonia gas is released, potentially endangering utility and concrete workers.
Fly ash with excess amounts of ammonia in disposal sites may emit an odor and/or impact groundwater.
Fly ash with high levels of ammonia is not acceptable for use in concrete.
Boral’s Gas-Phase Ammonia Slip Mitigation (ASM) Technology eliminates ammonia slip through the injection of oxidizers, enhancing the performance of SCR and SNCR systems. The chemical reagent treats the fly ash by converting the ammonia to harmless compounds, allowing its use in concrete applications and providing safer disposal operations. The treatment reagent can be added and blended with the dry fly ash at any point between the ash collection system at the power plant and final delivery to the ready mixed concrete producer.