Design of kraft pulp mill hot and warm water systems—A new method that maximizes excess heat

Many pulp mill hot and warm water systems are overdimensioned and produce more hot and warm water than demanded. This overproduction could be used for other applications, if heat could be released at high enough temperatures. In this paper a new method to release as much excess heat of a high temperature as possible in the secondary heat system has been developed.A case study of a Swedish kraft pulp mill showed that 5–6 MW excess heat with a temperature above 90 °C could be released if the system were rebuilt. Two different alternatives for using the excess heat have been investigated.