A model-based approach for simultaneous water and energy reduction in a pulp and paper mill

Pulp and paper mills receive much attention from environmentalist and authority due to their impact on natural resources, particularly in water and energy consumption. Many research works have been reported for water and energy savings for the pulp and paper mill. However, none of them were targeted at the brown stock washing system (BSWS), where significant water and energy are consumed to perform pulp cleaning and black liquor concentration. This paper presents an optimization model aiming for simultaneous water and energy saving for BSWS in the pulp and paper mills. A mixed integer non-linear programming (MINLP) model has been developed to optimize the water network design. The synthesized water network results in significant reduction in energy and water consumption. Sensitivity analysis is performed to analyse the relationship between washing efficiency and utilities (water and energy) consumption.