换热设备微生物污垢的动态模拟及影响因素分析

Dynamic simulation of microbial fouling in heat exchanger and analysis of affecting factors

在水温及流速恒定的实验工况下,利用自行研制的循环冷却水动态模拟实验装置,通过模拟不锈钢管换热器在硫酸盐还原菌以及铁细菌存在时循环冷却水系统的结垢特性,验证了Fe2+浓度、COD、细菌总数等水质参数与微生物污垢之间的关联性。实验结果证明硫酸盐还原菌和铁细菌的是导致污垢热阻增加的直接因素;铁细菌会为硫酸盐还原菌的繁殖提供厌氧的条件,两种菌类协同作用,导致微生物污垢的形成速度增快。各水质参数之间相互影响,决了定微生物污垢的特性。水质参数检测结果表明:Fe2+的含量和硫酸根的含量决定铁细菌和硫酸盐还原菌数量的多少,进而影响管壁黏泥量,pH值、COD、氨氮与SRB和IB繁殖代谢密切相关,从而影响了微生物污垢的形成。

This paper presented the dynamic simulation of an experimental facility of shell-and-tube recirculating cooling water.Under the experimental conditions of the constant water temperature and velocity,simulate the fouling situation in the stainless steel tube was simulated at the presence of sulfate-reducing bacteria and iron bacteria in recirculating cooling water system.The relevance between water quality parameters and fouling formation,such as Fe2＋concentration,COD and the total number of bacteria was obtained.The results showed that sulfate-reducing bacteria and iron bacteria were the main reasons of the fouling resistance increase.Iron bacteria provided anaerobic conditions for the breeding of sulfate-reducing bacteria,accelerating the formation of bio-fouling,and the interaction among various parameters codetermined the feature of bio-fouling.Analysis of water quality parameters showed that the concentrations of Fe2＋ and sulfate directly affected the number of iron bacteria and sulfate-reducing bacteria,thereby affecting the amount of wall slime.In addition,pH,COD and ammonia were also closely related to other bio-fouling formation factors,such as SRB and IB breeding metabolism.