Study on thermodynamic calculation of a coal-fired boiler retrofitted with pulverized coal oxy-fuel combustion

Four types of boiler were selected to analyze the feasibility of oxy-fuel combustion boiler retrofitted from existing conventional air boiler and the changes of the thermal performance parameters before and after retrofit. Research results show that the air boiler can operate in the oxy-fuel combustion atmosphere by adjusting the circulation ratio without any change of structure. CO2 has a high thermal capacity, resulting in uneven absorbing heating on the heating surface and the greatly decrease of flue gas rate, thus influencing safe operation of the boiler. Targeted improving the gas flow rate and reducing the heating surface area can achieve the oxy-fuel combustion boiler retrofits. The results show that the thermodynamic calculation parameters of after the oxy-fuel transformation boiler have reached the similar conditions of air atmosphere. Compared with air atmosphere, oxy-fuel combustion retrofit boiler have 0.7%~2.5% decrease on the volume thermal load and the sectional thermal load, and the total of flue gas reduces by about 20%, but the thermal efficiency of boiler increase by 0.42%~4.10%. ©, 2014, Huazhong University of Science and Technology. All right reserved.