增设加碱装置减缓热网循环水系统腐蚀的研究与实践

Research and Practice of Adding Alkali Device to Slow Down Corrosion of Circulating Water System in Heat Supply Network

对于兼顾城市热网供热的燃煤火力发电厂,分析城市热网换热设备和管道结垢和腐蚀的机理。反渗透产生的去离子水pH值较低,为5.9~6.5,使得铸铁或钢制管壁腐蚀产物变得容易溶解,导致铁离子浓度增加。用于热网补水的反渗透去离子水应适当提高pH值,增设氢氧化钠加药系统,将热网补水的pH值提高至10.5以上,碳钢、不锈钢就基本不产生腐蚀。

For the coal-fi red power plant which takes into account the heating of urban heat supply network,the mechanism of scaling and corrosion of heat exchange equipment and pipelines in urban heat supply network is analyzed.The pH value of deionized water produced by reverse osmosis is low,ranging from 5.9 to 6.5,which makes the corrosion products of cast iron or steel pipe wall easy to dissolve,resulting in the increase of iron ion concentration.The pH value of reverse osmosis deionized water used for heat supply network replenishment should be properly increased,and sodium hydroxide dosing system should be added to increase the pH value of hot water supply to above 10.5,and carbon steel and stainless steel will not be corroded.