摘要
换流站换流阀循环冷却水系统在运行过程中易发生设备腐蚀结垢、微生物繁殖及排污量大等问题。使用传统化学药剂阻垢存在运行成本高、易产生二次污染的问题。电化学除垢技术兼具除垢、防腐蚀、杀菌等功能,且不产生二次污染。针对国网浙江省某柔性直流换流站换流阀循环冷却水系统进行为期3个月的电化学除垢中试研究,在电流密度5 A·m^(-2),循环流量15 m^(3)·h^(-1)的最佳运行参数下,Ca^(2+)、Mg^(2+)及电导率呈现逐渐下降趋势,出水Ca^(2+)、Mg^(2+)及电导率分别控制在22 mg·L^(-1)、21 mg·L^(-1)及2300μS·cm^(-1)以下,余氯质量浓度达6.80 mg·L^(-1),COD去除率达46.15%,比能耗达17.10 Wh·L·mg^(-1)。处理后的冷却水对碳钢、不锈钢腐蚀速率分别小于0.0161 mm·a^(-1)、0.00003 mm·a^(-1),符合工业循环冷却水处理设计规范。对电极沉积水垢和冷却塔自然沉积水垢进行了扫描电镜、能谱分析和X射线衍射分析,发现电化学沉积水垢空隙小,结构疏松,有利于剥离和去除。电化学除垢系统的综合运行成本较原有加药阻垢系统大幅降低。本研究为电化学除垢技术在换流站换流阀循环冷却水系统中的应用提供了技术基础。
The equipment corrosion and scaling,microorganism propagation and large amount of pollution often occurs during operation of the circulating cooling water system of converter valve in converter station.Using traditional chemical additive for scale inhibition involves high operating costs and is prone to causing secondary pollution.Electrochemical descaling technology has many functions such as scale removal,corrosion prevention and bactericidal,without causing secondary pollution.The three-month pilot test of electrochemical descaling technology used in the converter valve circulating cooling water system in a flexible DC converter station of Zhejiang State Grid was explored.At the optimal operating parameters as follows:current density of 5 A·m^(2) and circulating flow rate of 15 m^(3)·h^(-1),the effluent Ca^(2+),Mg^(2+)and conductivity decreased gradually,and they were controlled below 22 mg·L^(-1),21 mg·L^(-1) and 2300μS·cm^(-1),respectively;the residual chlorine concentration reached 6.80 mg·L^(-1) and the removal rate of COD reached 46.15%,the best specific energy consumption was 17.10 Wh∙L·mg^(-1).After electrochemical treatment,the corrosion rates of circulating water on carbon steel and stainless steel were lower than 0.0161 mm·a^(-1) and 0.00003 mm·a^(-1),respectively,which could meet the industrial circulating cooling water treatment design code.Scanning electron microscope(SEM),Energy Dispersive Spectrometer(EDS)and X-Ray Diffraction(XRD)analysis were carried out on the scale deposited on the electrode of the pilot electrochemical device and the scale deposited in the cooling tower of the circulating water tank after long-term operation.It was found that after the electrochemical descaling process,the scale had smaller pores and loose structure,which is conducive to peeling and further removal.The comprehensive operation cost of the electrochemical descaling system is greatly reduced compared with the traditional chemical additive scaling control system.This study provides a technical basis
作者
明菊兰
傅乐伟
程一杰
周芳
冯礼奎
赖骁威
魏卡佳
刘润
MING Julan;FU Lewei;CHENG Yijie;ZHOU Fang;FENG Likui;LAI Xiaowei;WEI Kajia;LIU Run(State Grid Zhejiang Electric Power Co.Ltd.Research Institute,Hangzhou 310000,China;State Grid Zhejiang Electric Power Co.Ltd.,Zhoushan Power Supply Company,Zhoushan 316000,China;School of Environmental and Biological Engineering,Nanjing University of Science and Technology,Nanjing 210094,China)
出处
《环境工程学报》
CAS
CSCD
北大核心
2024年第8期2142-2154,共13页
Chinese Journal of Environmental Engineering
基金
国网浙江省电力有限公司科技项目(5211DS22000L)。
关键词
循环冷却水
电化学除垢法
中试实验
换流阀
circulating cooling water
electrochemical descaling
pilot-scale test
converter valve