基于污水换热器污垢不同生长阶段的除垢试验研究

为了提高污水换热器的除垢效果,文章以管壳式污水换热器为研究对象,以沙粒作为除垢粒子,以污垢热阻变化率表征除垢效果,在利用烘干灼烧失重法、能谱分析法和微观结构分析法分析污垢成分的基础上,运用污垢热阻法进行除垢试验研究。通过试验研究了在污垢生长的诱导期、生长期和渐近期3个阶段除垢对污垢热阻值的影响。试验结果表明:管壳式污水换热器管内污垢的主要成分为含水量较高的有机物;结垢工况下,污垢热阻渐近值为0.74×10^-3(m^2·K)/W;在污垢生长的诱导期、生长期和渐近期进行除垢后,污垢热阻渐近值分别为0.4×10^-3,0.42×10^-3,0.6×10^-3(m^2·K)/W,与结垢工况相比,污垢热阻渐近值分别降低了45.9%,43.2%,18.9%,除垢工况下污垢热阻增长速率较结垢工况明显减缓。

Descaling experiment resesrch on different growth stages of the fouling in the sewage heat exchanger

In order to improve the descaling effect of the sewage heat exchanger,the article takes the shell-and-tube sewage heat exchanger as the research object and uses sand as the descaling particles.The descaling effect is characterized by the change rate of fouling thermal resistance.Based on the analysis of fouling components by loss-on-drying and burning weightlessness,energy spectrum analysis and microstructure analysis,the fouling thermal resistance method is used to carry out the descaling experiment research.The effects of descaling on the fouling thermal resistance in the induction period,the growth period and the stabilization period are studied.The experiment results show that the main component of the fouling in the tube of the sewage heat exchanger is organic matter with high water content.In the scaling condition,the fouling thermal resistance asymptotic value is 0.74×10^-3(m^2·K)/W.The fouling thermal resistance asymptotic values of descaling during the induction period,the growth period and the stabilization period are 0.40×10^-3(m^2·K)/W,0.42×10^-3(m^2·K)/W and 0.60×10^-3(m^2·K)/W.Compared with the fouling thermal resistance asymptotic value of the fouling condition,the fouling thermal resistance asymptotic values reduce by 45.9%,43.2%and 18.9%.In the descaling condition,the increase rate of the fouling thermal resistance is significantly is significantly slower than that in the fouling condition.