Numerical study on acid condensation and corrosion characteristics of three-dimensional finned tube surface

Low temperature corrosion is a key factor affecting the performance and safety of heat exchanger for industrial waste heat recovery system. Acid dew point temperature and vapor condensation characteristics are two major parameters to evaluate corrosion behavior. However, previous studies focused solely on acid dew point temperature or condensation characteristics. In present paper, a numerical model was established to investigate the heat and mass transfer process of flue gas on three-dimensional finned tube surface and predict the acid dew point temperature and condensation characteristics simultaneously. Firstly, the effects of operation parameters were examined both by single variable method and orthogonal method. The results show that the flue gas inlet velocity and acid vapor concentration have the most significant effects on acid dew point temperature; the tube wall temperature and water vapor concentration have the most significant effects on the condensed acid solution concentration. Then, the corrosion characteristics was discussed and the optimization working parameters (the water vapor concentration in flue gas below 10.12% and the tube wall temperature above 349.3 K) are recommended.