Modeling and dynamic simulation of a bleach plant

• Published in: AIChE journal 1995-12, Vol.41 (12), p.2603-2613
• Main Authors: Wang, R. X., Tessier, P. J.-C., Bennington, C. P. J.
• Format: Article
• Language: English
• ISSN: 0001-1541; 1547-5905
• DOI: 10.1002/aic.690411209

A dynamic model of five‐stage (C+D)EDED bleach plant was developed using SIMNON a dynamic simulation language developed at Lund Institute of Technology, as a platform. The model is composed of individual modules that represent each bleaching stage. Each module includes chemical addition and mixing, diffusion and reaction in a retention towel, and washing. These unit operations are coupled with chemical kinetics for each bleaching stage using appropriate models. A relationship between the (C+D)E Kappa number and the input absorption coefficient to the D1 stage was used to link the delignification and brightening partial sequences of the bleach plant. The model, verified using steady‐state data, was used to model the dynamic response of the plant to step changes in production rate, (C+D) chemical addition, and incoming Kappa number, as well as the open‐loop response of the plant to a simulated variation in incoming Kappa number. The modular structure of the program allows a variety of bleach plants to be assessed once flow parameters and chemical kinetics are known. The dynamic model can also be used to develop and compare control strategies before being implemented at the mill.