An integrated approach to the optimisation of water usage and discharge in pulp and paper plants

Abstract

This paper is aimed at developing a systematic methodology for the cost-effective reduction of water usage and discharge in pulp and paper plants. As the industry moves towards increased system closure, the build-up of Non-Process Elements (NPEs) leads to serious consequences on the process equipment. In response, this paper achieves the following: a mathematical model to track water and primary NPEs throughout the pulping process; rigorous targeting for water usage and discharge; a systematic framework for water reduction using mass integration strategies including no/low cost techniques as well as capital-based techniques; an optimisation model for the optimisation of allocation, recycle and separation of aqueous streams. A case study for water management in a kraft pulping process has been solved to highlight the usefulness of the devised approach.