Abstract
The paper describes a study of the influence of Overfire Air (OFA) technology on heat and mass transfer parameters for a furnace chamber in the BKZ-75 boiler at the Shakhtinsk power plant (Kazakhstan); this plant is fueled with Karaganda high-ash coal. The computer simulation methods were applied for studying different air supply regimes through the air injectors operating in OFA design with different contributions: 0 (reference variant), 5, 10, 15, 18, and 20 %. The computer simulation of in furnace processes offers the distribution for total velocity vector, tempertaure field, NO 2 concentration field for the entire furnace and the exit zone. The study demonstrated that the operation with air injection at 18 % of OFA is optimal for combustion of high-ash coal. This operation mode offers a higher tempertaure at the flame core and a gradual tempertaure reduction at the chamber outlet; the latter feature is significant for chemistry of combustion products. The boiler under this operation mode offers a reduction of nitrogen oxide NO 2 emissions from the furnace.