EVALUATION OF THE USE OF CONDENSATE FROM AN EVAPORATION PLANT IN THE WOOD LOG WASHING PROCESS AT A PULP MILL

• DOI: https://doi.org/10.22533/at.ed.13176326270313

• Palavras-chave: Pulp industry; Condensate reuse; Kraft process; Water efficiency; Log washing.

• Keywords: Pulp industry; Condensate reuse; Kraft process; Water efficiency; Log washing.

• Abstract:

  The pulp industry is characterized by high water consumption and significant effluent generation, especially during the wood preparation and pulp washing stages. In the kraft process, the black liquor evaporation system generates large volumes of condensate, the reuse of which is still limited. This study evaluated the technical, economic, and environmental feasibility of reusing condensates from a multi-effect evaporation plant in log washing. The methodology was based on mass balances, industrial operational data, physicochemical characterization of the streams, hydraulic evaluation of the existing system, and economic analysis based on avoided costs. The results indicated a total generation of approximately 670 m³/h of condensate, with an operational surplus of about 140 m³/h currently directed to the effluent system. The characterization demonstrated that condensate B has a quality compatible with its controlled application in log washing, partially replacing industrial water, without the need to replace the main hydraulic equipment. The proposal resulted in reductions of approximately 1.7% in specific water consumption and effluent generation, as well as 17.7% in specific COD load, with an estimated payback period of 2.6 years. It is concluded that the reuse of condensate B constitutes a viable alternative aligned with the pulp industry’s water efficiency and sustainability guidelines.