涂布白卡纸机白水三级过滤分级回用新工艺的应用

Application of Innovative Three-stage Filtration and Graded Reuse Technology for White Water in Coated White Cardboard Machine

关键词:  白水回用  三级过滤  设备原理  清水节降

Key Words:white water recycling  three-stage filtration  equipment principle  freshwater consumption reduction

摘要:本研究介绍了某公司30万t/年白卡纸机白水循环系统清水节降新工艺。该纸机白水循环系统采用三级过滤方式，依次使用多圆盘过滤机、过滤器和15个盘的精细过滤器对白水进行处理，最终得到的滤液固体悬浮物（SS）含量≤10 mg/L，可部分替代清水，用于纸机网压部的高压喷淋以及湿部化学品的二次稀释，每天可节约清水2 976 m³，实现吨纸清水节降3.27 m³。但白水的不断回用，也使得BM4湿部系统阴离子垃圾（DCS）不断累积，对助留助滤剂体系造成干扰，助留助滤效果逐渐变差，导致三层流浆箱首程留着率逐渐降低，三层白水浊度和三层白水电导率逐渐升高。

Abstract:The paper introduced a new water-saving process for the white water circulation system of a 300 000 t/year white cardboard machine at the company, the white water circulation system of this paper machine adopted a three-stage filtration method. It successively utilized 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 gradual increase in the turbidity and conductivity of the white water from all three layers.