Abstract: After the continuous electrodeionization modules of Huaneng Henan Zhongyuan Gas Power Generation Company Limited operated for 4 years, the resistivity of the produced water decreased to 5MΩ·cm, and the mass concentration of SiO2 in the produced water increased to 120μg/L, so the produced water can not meet the production requirement already. Using the mixed liquids of 1.8%HCl，1.0%NaOH and 5.0%NaCl, the electrodeionization modules were cleaned respectively. Through debugging for several days, the function of the modules returned to normal; and the resistivity of produced water of the electrodeionization modules No.1 and No.2 increased to 18.26MΩ·cm and 17.30MΩ·cm respectively, which are very ideal results.

Key words: continuous electrodeionization (EDI) module, chemical cleaning technology, silicon dioxide, hardness, resistivity