Effect of Recirculated Flue Gas on Steam Parameters of 660MW Double Reheat Boiler

In order to solve the double reheat unit thermostat mode and heating surface heat absorption characteristics of large coupling difficult technical problems, the double reheat p-type boiler with a 660MW unit was taken as the object of study. The numerical simulation method which was carried out by using power station engineering system simulation software EBSILON and computational fluid dynamics software FLUENT, and field test method was introduced to study the effect of flue gas recirculation amount on the flue gas temperature at screen bottom, main steam temperature and reheat steam temperature under the different loads. The results show that the effect of flue gas recirculation amount on the flue gas temperature at screen bottom is little, the main steam temperature is not obvious, but the reheat steam temperature is significant. The reheat steam temperature shows a rising trend with the increase of the recirculating flue gas;The steam temperature deviation of the heating surface does not change with the amount of flue gas recirculation. The optimal flue gas recirculation rate of 660, 550 and 330MW are determined as follows: 15%, 18% and 30% of the three working conditions, which can provide theoretical guidance for the efficient, clean and stable operation of the double reheat boiler.