Neural Network Based Double-Objective Optimization and Application to Pulp Washing Process Improvement

Abstract

For a countercurrent paper pulp washing system, the requirements of craft to residual soda in the final washed pulp and Baume degree in the first stage filtrate tank are usually inconsistent. To compromise this pair of contradiction, a neural network (NN) based two-objective optimization algorithm is proposed. Two NN models of the residual soda in washed pulp and the Baume degree in the first stage filtrate tank are obtained by a two-step identification method. An external penalty function method based on the double-objective optimization algorithm on the hot clean water input and final washed pulp output is employed. In terms of the DCS development platform of Xinhua XDPS 4000, China, a novel pulp washing process DCS is implemented and put into operation in paper mills in China with notable profit.

Data-Driven Optimal Control for Pulp Washing Process Based on Neural Network

“…Most of these variables are interrelated, and an improvement in one variable may well have a favorable or unfavorable impact on the others. e primary objectives for achieving the best washing result are the lowest feed consistency, optimum mat formation with a uniform basis weight, a uniform shower liquor distribution, the highest discharge consistency, and minimal air content in the feed to the washer [13]. Pulp washing is a function of many variables, such as the amount of wash water, feed consistency, air entrancement, sheet formation, wash water distribution, and discharge consistency.…”

Iterative optimization of the economic efficiency of an industrial process within the validity area of the static plant model and its application to a Pulp Mill

“…According to Luyben (1989) it is usually much cheaper, safer and faster to conduct the optimization of plant operations on the basis of a mathematical model rather than experimentally. However, the significant number of studies is still concentrated on the optimization of single unit operations in Pulp Mills: Mcdonough, Uno, Rudie, and Courchene (2008) studied the optimization of the ClO2 requirements for the bleaching process; Tang, Wang, He, and Itoh (2007) optimized the Pulp Washing process; Sarimveis, Angelou, Retsina, Rutherford, and Bafas (2003) optimized the energy management in pulp and paper mills; Smith, Christlmeier, and Van Winkle (1986) studied the possibility of increasing of the recovery boiler throughput; Sidrak (1995) optimized the Kamyr Digester towards significant reduction in the amount of off-specification pulp. Klugman, Karlsson, and Moshfegh (2007) studied the energy consumption and production by the Pulp Mill; Savulescu and AlvaArgaez (2008) minimize the energy consumption through managing the direct heat transfer related to the water streams; Westerlund et al (1986) solved the equilibrium equations for the white liquor and optimized the lime feed rate; Santos and Dourado (1999) optimized energy consumption and the plant's production; Thibault et al (2003) concentrated their efforts on the multicriteria optimization of the plant.…”

Optimization of the Pulp Mill Economical Efficiency; study on the behavior effect of the economically significant variables

“…Due to the continuously increasing competition in the pulp and paper industry, there is a need to develop solutions that can increase the economical efficiency of the plants. However, the significant number of studies is still concentrated on the optimization of single unit operations in pulp mills: McDonough et al (2008) studied the optimization of the ClO2 requirements for the bleaching process; Tang et al (2007) optimized the Pulp Washing process; Sidrak (1995) optimized the Kamyr Digester towards significant reduction in the amount of off-specification pulp; Santos and Durado (1999) optimized energy consumption and the plant's production.…”