Optimization of the Exhaust Gas Oxygen Content for Coal-fired Power Plant Boiler

Abstract

During the running of utility boiler, the flue gas oxygen content is one of the most important factors that affects boiler efficiency, and it affects each other with other thermal economic parameters such as flue gas temperature, unburned carbon in fly ash and slag and coal consumption of power supply. So it's a key parameter to optimize the combustion process of fuel in utility boiler through combustion control system. Colligating the effect of flue gas oxygen content, flue gas temperature and unburned carbon in fly ash and slag on coal consumption, and aim for reducing coal consumption, the equations for associating flue gas temperature with power and oxygen content, and unburned carbon in fly ash and slag with power and oxygen content are obtained by three dimensional data fitting. And model for calculating boiler efficiency based on boiler heat balance is established. With the formula of coal consumption, the partial differential equation for calculating the variation rate of coal consumption is obtained, and optimal oxygen content is obtained through theoretical analysis and experimental research. The analysis of a 1000MW coal-fired power unit in Guangdong Province shows that the coal consumption operated at optimal oxygen content is reduced.