Corrosive Characteristic Research On Heat Pipe GGH After Wet Flue Gas Desulfurization In Power Plant

Heat pipe GGH has more advantages than normal heat exchanger, but the problem about corrosion has arrested its application in FGD of power plants. Therefore it is very necessary to carry out research on corrosive problem of Heat pipe GGH and find measures for engineering application.Discrete design model of heat pipe GGH is introduced and a VB program is compiled to test its correctness. This model will provide the necessary parameters for the numerical simulation about corrosive environment in heat pipe GGH.Computational fluid dynamics (CFD) software― FLUENT is used to simulate the basic corrosive environments such as temperature and flow field in heat pipe GGH. When the structure of heat pipe GGH changed, its influences on temperature and flow field are considered also. The results show that the tube pitch has an obvious influence on the temperature field and flow field will be homogeneous behind three lines of heat pipe.The FLUENT is also employed to simulating the consistence of sulfuric acid on the heat pipe's mural, the consistence field of sulfuric steam in flue gas and the deposition rate of sulfuric steam. When the structure of heat pipe GGH or the components of flue gas changed, their influences on the corrosive environment are considered also. It found that the tube pitch and the water steam in flue gas has an obvious influence on the corrosive range, the consistence of sulfuric acid and the deposition rate of sulfuric steam. In flue gas, the deposition rate of sulfuric steam reduces along its flow way and that in the cold side of the GGH is less than the hot side and that will go to stabilization in the middle of the GGH. While the component of sulfuric acid increasing, the deposition rate of sulfuric steam increase too, and this phenomenon is more obvious in cold side than in hot side.The corrosion experiment and electrochemistry testing are carried to study the anticorrosive performance of materials that heat pipe GGH often used. The influences on corrosion rate are studied from the aspects of the consistence of sulfuric acid and the mural temperature of heat pipe. The results show that the corrosion rate increases when the temperature of the sulfuric acid increasing and jumps at a specific temperature. The corrosion rate of ND steel is less than other steels that heat pipe GGH often used.The gray theory is introduced, then its correctness on material's lifetime predicting is tested by the data from the corrosion experiment. So it can be used to predict and evaluate the materials'lifetime that heat pipe GGH often used.