Study On Condensation Characteristic Of Sulfuric Acid Vapor On Low-temperature Heating Surface For Coal-fired Boiler

With the rapid development of China's economy, the energy consumption is growing, and the commercial power to get fast growth, driving the whole society at a high growth rate of electricity consumption, China's generating capacity has maintained a rapid growth trend. Thermal power still occupy a large proportion in power generation industry in China. In the foreseeable time, Thermal power still occupy a large proportion in China's power generation industry. In the foreseeable period of time, China's consumption of coal-based energy consumption patterns will not change.The combustion of fuels in utility boiler emits large quantities of pollutions,SO3 included. Sulfuric acid vapor from power plant firing fuel can cause low temperature corrosion of the co-components,once the temperature of flue gas is blow the acid dew point. With the increase of the capacity of thermal power plant, corrosion studies on low-temperature heating surface even more urgent, and sulfuric acid vapor condensation rate is an important factor affecting the low temperature corrosion.In this paper, a mathematical model for describing the concentration of acid solution on the low temperature wall is established by using the theory of phase equilibrium and fugacity equation theory. Based on this model, a MATLAB program was written to predict the concentration of acid concentration in the wall, which was the boundary condition of the Fluent numerical model. The user defined function(UDF) was written, and the condensation rate of sulfuric acid vapor under different flue gas conditions was investigated. The results show that the increased content of water vapor in the flue gas and the low wall temperatures will reduce the acid concentration on the wall. And increasing the wall temperature will reduce the condensation rate. With the increase of the volume fraction of acid vapor and the flue gas velocity, acid vapor deposit rate increases. At the same time, the water vapor has few effects on the deposit rate.At the same time, the experimental platform is set up and the results are verified by numerical simulation. The results show that the numerical results are in good agreement with the experimental results, which proves the validity and reliability of the numerical model.For the condensation deposition of sulfuric acid vapor in the low temperature surface, the numerical simulation method has very important practical value, which provides a reliable theoretical basis for the design of the low temperature heating surface and the formulation of anti-corrosion measures.