Abstract The bleaching sector of the wood pulp industry is its largest effluent generator. The aim of this study was to reuse the bleaching filtrate in order to reduce water consumption. The experiment was conducted by simulating the D0(EP)D1 bleaching sequence and recirculating different amounts of filtrate from the oxidation stage to control the pulp consistency of the delignification stage (pre-O). Physical, mechanical, chemical and optical properties of the pulp were studied. The accumulation of the non-process elements (NPE) and their effects were evaluated with the Aspen-Plus® computer simulator. The results of the computational modeling were satisfactory. The recirculation of filtrates increased the saturation index of the system by 19 %, but remained at sub-saturation levels. The pulp viscosity and elongation remained statistically stable. Recirculation of up to 50 % of the filtrate did not produce differences in pulp brightness; however, there were slight losses in the pulp resistances. In order to maintain 84 % ISO brightness, there was a higher consumption of the bleaching reagents. Up to 50 % of recirculation of the filtrates was accomplished without jeopardizing the system and the pulp quality and resulted in a savings of 55 m3 h−1 of water – 7 % of the consumption of the entire mill.

中文翻译：

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ECF 漂白厂滤液的部分回路闭合

摘要 木浆工业的漂白部门是其最大的废水产生源。本研究的目的是重复使用漂白滤液以减少用水量。该实验是通过模拟 D0(EP)D1 漂白顺序和循环不同量的来自氧化阶段的滤液来控制脱木素阶段 (pre-O) 的纸浆稠度来进行的。研究了纸浆的物理、机械、化学和光学特性。非过程元素 (NPE) 的积累及其影响使用 Aspen-Plus® 计算机模拟器进行评估。计算建模的结果是令人满意的。滤液的再循环使系统的饱和指数增加了 19%，但仍保持在亚饱和水平。纸浆粘度和伸长率在统计上保持稳定。高达 50% 的滤液再循环不会产生纸浆白度的差异；然而，纸浆阻力略有下降。为了保持 84% 的 ISO 亮度，漂白剂的消耗量更高。在不危及系统和纸浆质量的情况下实现了高达 50% 的滤液再循环，从而节省了 55 m3 h-1 的水——占整个工厂消耗量的 7%。