Fundamental Study On Coal Combustion And Furnace Radiation Heat Transfer Character Under Oxy-fuel Combustion

CO2,SOX and NOX produced in the coal combustion pollute the environment badly. Many scholars in the world have studied on the methods to control contaminations released in coal combustion. But these techniques are basically single and have some disadvantages. The combustion style which can simultaneously curb CO2, SOX and NOX as well as other pollutant will be the most competitive and promising, so is a new coal combustion style developed in recent years-O2/CO2 recycling combustion. Research on this combustion style has very important scientific meaning and practical meaning. This dissertation summarizes researchful actuality and developmental current of O2/CO2 recycling combustion. This dissertation focuses on the combustion characteristics of pulverized coal under oxy-fuel combustion, as well as radiation heat transfer characteristics of furnace through a lot of experiments and theoretical calculations.Firstly this paper uses thermal analyzer and small tube furnace to study combustion characteristics of pulverized coal of conventional combustion and oxy-fuel combustion, on this basis, to study the differences of temperature, individual properties of oxygen concentration and CO2 concentration affection on coal combustion, and also the analysis of the kinetics of pulverized coal combustion characteristics. The result indicates that: as the effect of thermal properties of CO2, comparing with the conventional combustion, under oxy-fuel combustion of pulverized coal, ignition point and burn-out points are delayed; increasing O2 concentration to some extent improved the performance of coal combustion. Secondly, the conventional radiation heat transfer formula be amended and for oxy-fuel combustion radiation heat transfer which including the different recirculation ratio, gas decomposition products affection on adiabatic flame temperature, the furnace heat transfer characteristics. The result indicates that: for dry flue gas, wet flue gas recycling rate of 0.71, 0.67, access the same performance as conventional combustion radiation heat transfer properties. Finally, based on thermal analysis software IECM, we analyze the economics of oxy-fuel combustion and the conventional combustion + ammonia absorption of CO2 of different capacities. The total cost and plant efficiency are calculated and compared. Research shows that: Compared to conventional combustion, under oxy-fuel combustion the efficiency of power stations improves, but an increase in costs. And oxygen combustion method is more suitable for large units.The study of oxy-fuel combustion technology will lay a foundation in practical application.