EDI运行内阻陡升的原因及应对措施

The Cause of EDI Rising Internal Resistance and its Countermeasures

EDI设备在正常运行过程中出现电压不断升至高限(350 V以上),电流逐渐下降趋于零,产水电阻率低至2 MΩ·cm以下,除盐率降至30%的现象,但各个进水压力,压差均正常,原因是模块内的阴树脂可能被某羧酸盐类的有机物包裹,使阴树脂失去离子交换的能力,且该污染难以通过常规的酸碱清洗及通电再生进行恢复。采取部分模块更换,同时优化自控程序、加强水质监测及管路改造等措施后,经过1 a的运行观察,新旧设备性能稳定,产水电阻率均符合锅炉补给水的水质要求。

During the normal operation of EDI equipment,the voltage continuously rose to a high limit( above 350 V),the current gradually decreased to 0,the resistivity of water production was lower than 2 MΩ·cm,and the desalination rate dropped to 30%. However,the inlet pressure and the differential pressure were normal. Maybe the anion resins in the module were wrapped up by some carboxylate organic compounds,so that the anion resins lost the ion exchange capacity,and the pollution cannot be recovered by conventional acid-base cleaning and electrified regeneration.Taking some measures such as replacing some modules,optimizing the auto-control program,strengthening water quality monitoring and reforming the pipeline,the new and old equipments are stable in performance during the recent one year,and the resistivity of water production conforms to the water quality requirement for the boiler feedwater.