On Modeling and Identification of a Continuous Pulp Digester

Abstract The main contribution of this paper is to introduce a procedure for modeling and identification of the continuous paper pulp digester. The technique should, however, be applicable to similar distributed parameter processes. The approach taken is gray box identification, where partial physical information is utilized in order to specify model structures. The method of orthogonal collocation is applied in order to approximate the distributed parameter system with a low-order lumped parameter state space model. Simulations of identified models with structures of different complexity arc presented.