海水冷却水析晶污垢分析及其生长模型

摘要

Cooling seawater is used generally in petrochemical industry,power generation and shipping,however crystallization fouling of seawater would deteriorate heat transfer and increase energy consumption. The experiments of crystallization-fouling by seawater were conducted under static condition. The crystallization fouling composition was analyzed by XRD,and the results showed that seawater fouling was CaSO4·2H2O and Mg(OH)2. A crystallization-fouling growth model was proposed asm=ke−bt+M0,and the experimental data of different roughness metal at 80℃ was fitted to the correlation with maximum relative error of 15.7%. The crystallization-fouling correlation and the growth curve showed that induction period,growth rate and mass of seawater crystallization-fouling were closely related to fouling-ions properties,super-saturation and metal surface roughness. When roughness of metal decreased,induction period of crystallization fouling became longer and grown rate became lower.%海水冷却水广泛应用于沿海地区的石油、化工、电力和船舶领域，但是海水容易引起严重的析晶结垢，从而降低换热效率和运行能耗。本文对海水析晶污垢的形成过程进行了静态实验研究，通过XRD分析了海水析晶污垢的组成，结果显示污垢主要成分为CaSO4·2H2O和Mg(OH)2。本文提出了海水析晶污垢的生长模型，推导了污垢生长曲线关联式m=ke−bt+M0，拟合了80℃时不同表面粗糙度试片的海水析晶污垢生长关联式和生长曲线，拟合最大相对误差15.7%。海水析晶污垢生长关联式和生长曲线显示，海水析晶结垢的诱导期、污垢生长速率和结垢量与海水中成垢离子的晶体生长活化能、过饱和度以及换热试片的表面粗糙度有关，试片的粗糙度越小，海水析晶结垢的诱导期越长，生长速率越慢。