Steady state behavior and maintenance planning of bleaching system in a paper plant

This paper presents the steady state behavior and maintenance planning of the bleaching system in a paper plant. The paper plant comprises of various systems including feeding, chipping, digesting, wash-ing, bleaching, screening, stock preparation and paper making, etc. One of the most important functionaries of a paper plant, on which quality of paper depends, is the bleaching system, where removal of coloring constituents is done to obtain the desired degree of brightness. The bleaching system consists of two subsystems A and B arranged in series with two states; good and failed. The mathematical modeling is carried out on the basis of Markov birth-death process using a probabilistic approach. An expression for steady state availability is also developed. Based upon the maintenance data available from medium sized paper plant, the effect of each working unit on the system availability behavior has been explained. In this regard, the behavioral chart for bleaching system has been given. Besides, a maintenance schedule has also been suggested and utilized for the purpose of maintenance planning of the bleaching system in a paper plant. The findings of this paper have been discussed with the concerned plant personnel and found to be highly beneficial for enhancing the performance level of the plant concerned.