Study On Dynamic Characteristics Of Boiler Convection Heating Surfaces Under Oxy-fuel Combustion Condition

Slather using of the fossil fuel makes the greenhouse effect increasing greatly. Theresearch and demonstration project of the carbon capture and storage have become a veryimportant task in the field of thermal power generation. The oxygen-fuel combustiontechnology is a new technology which can trap high concentration CO2directly withoutseparation and control pollutant emission comprehensively. The existing researchesmainly include combustion mechanism, combustion condition and pollutant formationcharacteristics and so on, however the research is relatively less about whether or notthere are differences about the dynamic heat transfer characteristics of convection heatingsurfaces between oxygen-fuel combustion condition and conventional air combustioncondition. Hence study on the dynamic heat transfer characteristics of boiler convectionheating surfaces under oxygen-fuel combustion condition is of great significance.In this paper, a300MW boiler was taken as the research object. Firstly, thecharacteristics and system composition of oxygen-fuel combustion technology are brieflyintroduced, and then the physical properties of flue gas which was produced by O2/CO2(30:70) oxygen-fuel combustion and1MPa pressurized oxygen-fuel combustion arecalculated with ASPEN software, and compared with that was produced by conventionalair combustion. On the basis of the calculated properties of flue gas, the boilerthermodynamic calculation was performed under conventional air combustion、oxygen-fuel combustion and1MPa pressurized oxygen-fuel combustion conditions, itprovides data for the research of dynamic characteristics of convection heat transfersurfaces.Then according to the structure and operation characteristics of boiler convectionheating surfaces, the numerical simulation on dynamic heat transfer characteristics ofconvection heating surfaces in different combustion conditions was performed firstlywith FLUENT software, secondly the simulation research on dynamic heat transfercharacteristics of the calculated convection heating surfaces was performed with Matlabsoftware, and analyzed the results of two kinds of research to determine the differencesand causes of dynamic characteristics of convection heat transfer surfaces under differentcombustion atmosphere conditions, and obtained the dynamic response time and temperature of the working medium. The calculation plays an important role inoptimization, design and control of oxygen-fuel combustion technology.