390MW燃气-蒸汽联合循环机组炉水磷酸盐加药自动控制实现途径

Realization Approach for Automatic Control for Boiler Water Phosphate Dosing for 390MW Gas-steam Combined Cycle Unit

针对目前火力发电厂炉水调节过程中加磷酸盐主要以人工为主、成本高、劳动强度大的问题,提出利用低压炉水与中、高压炉水在线电导率差值和中、高压炉水pH表输出信号与磷酸盐加药泵联锁,以实现中压和高压炉水磷酸盐自动启动和停止加药的建议,利用intouch组态和VB编程实现全自动加药的逻辑控制.自动加药实施后炉水的pH值为9.2～9.6,磷酸根的质量浓度维持在0.5～3 mg/L的低磷酸盐水平,水质合格率由99.2％提高到99.95％,余热锅炉未出现明显的磷酸盐“隐藏”现象.

Aiming at problems such as manual work primarily, high cost and strong labor intensity in dosing phosphate during the period of boiler water adjustment for thermal power plant, this paper proposes to use differential value of low pressure boiler water and medium and high pressure boiler water online conductivity and interlock of output signals of medium and high pressure boiler water pH meter and phosphate dosing pump to realize automatic startup and stop for dosing of medium and high pressure boiler water phosphate. By using intouch configuration and VB programming, it is successful in realizing logic control for full-automatic dosing. After implementing automatic dosing, the pH value of boiler water is 9.2-9.6, mass concentration of carbonate keeps at low phosphate level of 0. 5-3 mg/L while percent of pass of water is improved from 99.2% to 99.95% and no hidden phosphate is existing in waste heat boiler.