Grouping eucalyptus species in kraft pulp process for cost reduction

Abstract

The objective of this research is to study the level of the important factors that can decrease total cost of pulp
production. First of all, experts and experienced users identify the factors that affect the total production cost
by applying the principle of 4M 1E cause and effect diagram. Then the primary factors were chosen based on
80% of their significance and tested by hypothesis for two population means. It was found that at the 95%
confidence level the significant factors that have effects on the total production cost are amount of Effective
alkali in white liquor and Kappa number. However, the proportion of easy delignification according to Eucalyptus
species is considered as a significant factor based on various studies. Box-Behnken experiment is designed
with respect to 3 mentioned factors and 3 levels of each factor. The response surface method (RSM) is employed
to determine the non-linear relation between the total cost as the response and the proportion of easy
delignification, amount of Effective alkali in white liquor and Kappa number. To minimize the total cost, the optimal
values of each factor are 75% of easy delignification, 112 grams per liter of Effective alkali in white liquor and
13.5 of kappa number. Under this optimal condition, the average total cost per ton of Eucalyptus is 13,393.91
Baht which is significantly less than the total cost of 15,517.06 Baht per ton before improvement.