Jean-Christophe Bonhivers

Applications of Process Integration Methodologies in the Pulp and Paper Industry

Abstract: This chapter describes the mass and energy requirements of pulp and paper processes in general, and specifically the Kraft process, which is the dominant pulping process as well as the most intensive steam user. The strong interactions between water and heat networks in pulp and paper mills are discussed. Water in pulp and paper processes is used for dilution, washing, cooling and heating, and is the main heat transporter and dissipator in pulp and paper processes. Approaches to increasing energy efficiency in existing mills are presented. Results show that there is a heat-savings potential of approximately 15–30% in typical existing mills. Finally, trends in Process Integration techniques in the pulp and paper industry are presented.

Simultaneous Water and Energy Minimization for Brown Stock Washing System

Abstract Pulp and paper mills are huge consumers of water and energy. Hence, much research works have been dedicated to simultaneous reduction of water and energy in the past decades. However, none of those works are addressing the brown stock washing system (BSWS), which is the core processing section that determines the amount of energy required in black liquor (BL) concentration. The latter is the largest energy consumption in a typical pulp and paper mill. Therefore, minimizing water consumption in the BSWS will lead to energy saving too. In this work, mass balances of the BSWS is first analyzed in a process simulation software (Cadsim), and adopted as the base case model for the study. Next, a mixed integer non-linear programming (MINLP) optimization model is developed to minimize the total annualized cost incurred in the project. The synthesized water network features significant reduction in both energy and water consumption in the BSWS.