涂布白卡纸机白水三级过滤分级回用新工艺的应用OA

The paper introduced a new water-saving process for the white water circulation system of a 300 000 t/year white cardboard ma-chine at the company,the white water circulation system of this paper machine adopted a three-stage filtration method.It successively uti-lized a multi-disc filter,a filter,and a fine filter with 15 discs to treat the white water.The final filtrate obtained had an suspended solids(SS)content of≤10 mg/L and could partially replace fresh water.It was used for high-pressure spraying in the press section of the paper machine and for the secondary dilution of wet-end chemicals.This process saved 2 976 m³ of fresh water per day and achieved a fresh water reduction of 3.27 m³ per ton of paper produced.However,the continuous reuse of white water also led to the continuous accumulation of anionic trash(DCS)in the BM4 wet-end system,which interfered with the retention and drainage aid system.As a result,the performance of retention and drainage aids gradually deteriorated,leading to a gradual decrease in the first-pass retention rate of the three-layer headbox,as well as a grad-ual increase in the turbidity and conductivity of the white water from all three layers.