Analysis of the Influence of Boiler Parameters on the Flue Gas Recirculation Rate of the Second Reheat Unit

Compared with the primary reheat unit, the secondary reheat unit can effectively reduce the coal consumption of the unit and improve the efficiency of the coal-fired power plant. This paper takes the secondary reheat million unit as the research object, simulates the boiler with Ebsilon software. The boiler operation under different loads is analyzed. The maximum error of the model verification results is about 5%, which is considered to be reliable. Then the regulation mode of reheat steam temperature is deeply discussed. The main research work is to study the effects of load, coal quality, excess air coefficient and feedwater temperature on flue gas recirculation rate (FGR) on the premise of controlling the intermediate point temperature. The results show that under the condition of constant intermediate temperature, FGR decreases with the increase of load at low load and almost remains unchanged at high load; The FGR rate is inversely proportional to the excess air coefficient; With the increase of excess air coefficient, the FGR rate decreases; The FGR rate of low calorific value and high moisture coal is low, and the influence of low volatile and high ash coal on reheat steam temperature is great; The feed water temperature are inversely proportional to the flue gas recirculation rate.