Numerical study on coupled condensation of sulfuric acid and steam in heat exchanger for waste heat utilization
JIANG Wei1*, JIANG Ting2, ZHU Xiangyuan3
1. College of Water Resources and Architectural Engineering, North A&F University, Yangling, Shaanxi 712100, China; 2. Xi′an Ae-rospace Pump Co. Ltd., Xi′an, Shaanxi 710100, China;3. Key Laboratory of Thermal Fluid Science and Engineering of MOE, Xi′an Jiaotong University, Xi′an, Shaanxi 710049, China
Abstract Low-temperature corrosion characteristics of flue gas heat exchanger surfaces are the key factors affecting the reliability of equipment operation. And an accurate prediction of condensation of sulfuric acid vapor is crucial for investigation into the mechanism of low temperature corrosion characteristics. A coupled numerical model was adopted to predict the condensation of sulfuric acid vapor on the heat exchanger surfaces. By integrating the vapor-liquid equilibrium data of H2SO4-H2O solutions and multi-component diffusion theory, a model for the sulfuric acid pressure on the fin surfaces under the coupled condition is obtained. A rectangular type finned tube heat exchanger was employed to identify the effect of acid vapor content and water vapor content on the sulfuric acid condensation and corrosion by using CFD. The results show that the distribution of acid solution concentration is dependent on the fin temperature. The fin regions with higher temperature also are subject to a higher acid solution concentration. An increase in water vapor concentration can result in a sharp reduction in acid solution concentration and an increase in deposition, indicating a severe risk of low-temperature corrosion. The results can be used as a reference for the safety design of heat exchangers.
JIANG Wei-*,JIANG Ting-,ZHU Xiang-Yuan-. Numerical study on coupled condensation of sulfuric acid and steam in heat exchanger for waste heat utilization[J]. Journal of Drainage and Irrigation Machinery Engin, 2019, 37(5): 420-426.
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