Use of Computer Modeling for Closed-Cycle Assessment and Design, 1996 International Pulp Bleaching Conference Proceedings

P. Gleadow

H.A. Simons Ltd

C. Hastings

AF-IPK

Closed-cycle designs offer promise in that they are compatible with both existing and new bleaching technologies, yet through alignment of design objectives with both public and client expectations, may offer more durable long term solutions to the challenges facing our industry. Many mills exploring or implementing bleach effluent recycle use computer simulation as an integral tool to planning implementation. These include Union Camp (Joseph, 1996), Champion (Caron, 1995). Weyerhaeuser (Holman 1994) and Louisiana Pacific (Martin 1996) in the US and MoDo(Ahlenius 1996), Södra, Stora (Naslund 1996) and Lenzing (Krotscheck, 1995) in Europe. Part of the current progress toward mill close-up can be attributed to the use of computer modelling as tool in developing process understanding, knowledge and design. This poster discusses the development and application of computer process simulation within the authors’ Organisation for research and design of chemical pulp mills with increasing levels of process water reuse. The methods and models presented here have been used by Simons for: . Research, in the: Paprican-Simons “Towards Closed-cycle Kraft” research program (Canada); CSIRO (Australia) National Pulp Mills Research Program; and Papro (New Zealand) “Inorganic Chemistry of Closed-Cycle Kraft” research program. . Mill studies, in which the approaches, costs and risks for closed-cycle application in client mills are developed. . Closed-cycle engineering, design and construction. The models have been developed based on mill design experience, current research and mill sampling programmes. Individual models to be discussed include the: Overall Material Balances (OMB); Multi-Component Fibreline and Multi-Component Recovery Cycle models; and Water and Energy Balance models.