Corrosive And Anticorrosive Research On Reinforced Concrete Chimney After Wet Flue Gas Desulfurization In Power Plant

Flue gas from coal-fired power plant exist a certain amount of SO3, which will reduce the acid gas dew point significantly. As the temperature of the smoke after wet desulfurization (FGD) below the acid dew point, the sulfuric acid vapor form by water vapor and SO3 in flue gas will condense down, resulting in low-temperature corrosion of concrete chimney. This paper based on the analysis of the flue gas corrosion and pilot study of migration and transformation of erosion corrosion factor present in the environment to predict the corrosion in power plant case, to find out the corresponding measures to protect the chimney from corrosion, and to play a guiding role to the safe operation of power plants.This paper first determined the existence of the corrosion factor as SO2,NOx,HCl,HF,SO3 and water vapor in flue gas, The conclusion is that the main corrosion factor is SO3 and water vapor. Then we do some experimental study on the coagulate process on the corrosion factor,the composition of condensate was tested under the temperature at45℃and 50℃and condensation time at 2s,4s,6s and 8s.then select the appropriate method from the existing calculation of dew point method to test changes of the acid gas dew point under the experimental conditions. Analyze corrosion environment of the chimney in power plant. The results show that, the smoke after FGD has a strong corrosion. Chemical corrosion was reduced from FGD exports the flue to the chimney.Corrosion factor of the flue gas conversion to liquid and form a new corrosion environment, this paper introduce the accelerated corrosion experiment of reinforced concrete specimens to study the effects of liquid environments on the corrosion of chimney materials in power plan and analyzed the corrosion mechanism. Then weight loss,compressive strength,impermeability,neutralization depth and Cl-,SO42-penetration depth of concrete specimens was tested under different corrosion age. The results showed that smoke condensate corrosion to reinforced concrete is decomposition erosion in formation of sulfuric acid-based erosion under multi-factor. The decomposition erosion would be a serious impact to security in power plant.CFD-based platform, using Fluent to simulate distribution of the gas flow velocity,pressure and temperature in the chimney, analyze physical and chemical erosion results of each part of chimney in the power station under the influence of the flue gas temperature, pressure and flow and find out the worst erosion part of the chimney. The results show that:import and export region of the chimney suffer the most serious corrosion.Finally, put forward measures to weaken the chimney corrosive environment by the operation of power plants, describes the current common anti-corrosion coating and lining in the chimney.