Dissemin is shutting down on January 1st, 2025

Published in

De Gruyter, Nordic Pulp & Paper Research Journal, 3(35), p. 471-478, 2020

DOI: 10.1515/npprj-2020-0028

Links

Tools

Export citation

Search in Google Scholar

Partial circuit closure of filtrate in an ECF bleaching plant

Distributing this paper is prohibited by the publisher
Distributing this paper is prohibited by the publisher

Full text: Unavailable

Red circle
Preprint: archiving forbidden
Red circle
Postprint: archiving forbidden
Orange circle
Published version: archiving restricted
Data provided by SHERPA/RoMEO

Abstract

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.