Temperature Management Considerations in Closed Water Loop Deinking Plants, 1998 Recycling Symposium Proceedings

Most deinking plants can operate at designed temperatures for process and effluent when sufficient cool fresh water is introduced as make-up water at various points throughout the system. However, closing the white water system to save fresh water and reduce effluent flows can result in serious temperature management problems in many office paper deinking plants.

Temperature management is an important part of the design of any deinking plant. There may be temperature targets for many of the operations which occur in the complex deinking plants that we are building and operating today. Heat is added to several parts of most of the plants to obtain the desired temperatures required for pulping, oxidative bleaching, reductive bleaching, and dispersion with little thought given to the detrimental effects high temperatures may have on other parts of the process. Even operations external to the deinking plant, such as effluent treatment plants may be severely impacted, especially during summertime operation.

This paper will discuss some of the more common temperature related problems which have been encountered in modem office waste deinking plants and some solutions which are being employed in a number of these plants.