Numerical predictions of sulfuric acid corrosion on novel heat transfer surfaces

doi:10.11949/j.issn.0438-1157.20160603

Abstract

Abstract:

Low temperature corrosion determined by the sulfuric acid dew point temperature and the sulfuric acid vapor and water vapor condensation rate is an important reason denoting the failures of heat transfer equipment. In this study, the sulfuric acid dew point temperature and sulfuric acid vapor and water vapor condensation rate on the wall and fin surface are calculated by considering both the vapor-liquid equilibrium effect and multi-component diffusion effect. In addition, the local distribution of acid dew point temperature on the fin surface is numerically predicted. It provides a precise guidance for the design of heat exchanger. The results show that the acid dew point temperature is affected by the factors of fuel type, fly ash particle (size and quantity) and structure of heat transfer fins. The fuel type, which affects the flue gas compositions and the combustion temperature, plays an important role on the sulfuric acid dew point temperature. The condensation of the sulfuric acid vapor on the ash particle surface leads to the decrease of sulfuric acid dew point temperature. The studied novel heat transfer fins (the H-type fin with compound dimples and rectangular longitudinal vortex generators) can reduce the local sulfuric acid dew point temperature and the sulfuric acid vapor and water vapor condensation rate on the fin surface.

Key words: sulfuric acid dew point, sulfuric acid vapor condensation rate, water vapor condensation rate, novel fins, surface, numerical simulation, prediction

摘要：

低温腐蚀是造成换热设备失效并降低其经济性的重要原因。基于汽液平衡理论和多组分扩散影响数值模拟了不同换热管管壁表面及翅片表面酸露点温度和酸蒸气、水蒸气冷凝沉积速率等影响低温腐蚀的相关因素，数值预测了换热表面局部酸露点温度，为换热器精细设计提供指导。结果表明，燃料类型、飞灰颗粒和翅片结构均会对换热表面酸露点温度造成不同程度影响。燃料类型决定烟气成分和燃烧温度，对酸露点温度影响较大；烟气中飞灰颗粒的存在会降低酸露点温度；翅片结构能够改变周围烟气速度，影响酸露点温度和壁面上酸蒸气、水蒸气冷凝沉积速率。基于以上数值研究提出丁胞和矩形纵向涡复合H型翅片结构可降低壁面上烟气酸露点温度，降低酸蒸气、水蒸气冷凝沉积速率。

关键词: 硫酸露点, 酸冷凝沉积速率, 水冷凝沉积速率, 新型翅片结构, 表面, 数值模拟, 预测

CLC Number:

TK124

WANG Yuchen, TANG Guihua. Numerical predictions of sulfuric acid corrosion on novel heat transfer surfaces[J]. CIESC Journal, 2016, 67(S1): 76-83.

王禹晨, 唐桂华. 新型换热表面硫酸腐蚀特性的数值预测[J]. 化工学报, 2016, 67(S1): 76-83.

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