不锈钢缩放管中典型致垢微生物致垢能力

摘要

This study simulated dynamical fouling process of three fouling microorganisms, i.e. iron bacteria (IB),sulfate-reducing bacteria (SRB),and slime forming bacteria (HB),and their mixtures isolated from the slime in the bottom of circulating cooling tower. Experimental conditions were kept constant at 30 ℃ water temperature and 0.4 m/s flow rate. The fouling resistances for IB,SRB,HB and their mixture were by ICP-MS and anion analysis of fouling samples was investigated. The results showed that the induction time of fouling for the four groups were 28 h,45 h,70 h and 18 h, respectively. The fouling resistance asymptotic values were 2×10−4 m2·K/W,1.75×10−4 m2·K/W,1.45 ×10−4 m2·K/W and 4.9×10−4 m2·K/W,respectively. The fouling abilities of the four groups were in the order of mixture>IB>SRB>HB. The composition analysis of fouling samples showed that IB contained relatively high concentrations of Fe,C and NO3−,and low contents of heavy metal ions and Cl−, indicating abilities of strong fouling and weak corrosion. The SRB sample contained mainly S, Fe,Cl−,Ni and Cr,indicating strong corrosion abilities. The HB sample mainly contained C,N, NO3−and certain amount of Cl−,showing its ability of corrosion.%　　以电厂循环冷却塔塔底黏泥中分离纯化出的3种致垢微生物铁细菌（IB）、硫酸盐还原菌（SRB）、黏液形成菌（HB）为实验菌种，利用污垢热阻动态模拟实验台，在恒定工况下（水温30℃，流速0.4 m/s），动态模拟了3种致垢菌及其混合菌的微生物污垢形成过程。实验测得了3种致垢菌和混合菌的污垢热阻，并对垢样成分进行了ICP-MS和阴离子分析。结果表明：污垢诱导期分别为28 h、45 h、70 h和18 h；污垢热阻渐近值为210−4 m2·K/W、1.7510−4 m2·K/W、1.4510−4 m2·K/W和4.910−4 m2·K/W。由此表明致垢菌的致垢能力大小为：混合菌＞IB＞SRB＞HB。垢样成分分析结果表明：IB 垢样成分分析中 Fe、C 和 NO3−含量较多，而重金属离子及Cl−含量较少，说明其具有较强的致垢能力而腐蚀能力较弱；SRB垢样分析显示，S、Fe及Cl−相对较高，且重金属Ni、Cr含量较多，说明其致垢的同时具有较强的腐蚀特性；HB形成的污垢主要以C、N及NO3−为主，且含有一定量的Cl−，表明此菌也具有一定的腐蚀性质。