Energy efficiency study of the paper making drying process

Pulp and paper industry is a highly energy intensive and the drying section of the paper machine consumes 64 % of total energy. The heat of the humid hot air resulting from the drying process has a usable energy potential which has to be recovered and represents a secondary energy resource. This paper analyses efficiency of introducing a complex heat recovery, in three stages, integrated into the drying process of the paper production technology line. The type of recovery used is an interior recuperation in the first and third stage due to the fact the energy contained by the secondary energy resources, namely the heat of the exhausted hot air from the drying process, is recovered within the process itself. In the second stage, the secondary energy resource has an energetic potential since it is used to maintain the microclimate in the industrial hall. The performed energy analysis is leading to conclusions regarding the methodology for establishing the optimal regime of operation.