Grouping eucalyptus species in kraft pulp process for cost reduction

摘要

The objective of this research is to study the level of the important factors that can decrease total cost of pulpproduction. First of all, experts and experienced users identify the factors that affect the total production costby applying the principle of 4M 1E cause and effect diagram. Then the primary factors were chosen based on80% 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 Effectivealkali in white liquor and Kappa number. However, the proportion of easy delignification according to Eucalyptusspecies is considered as a significant factor based on various studies. Box-Behnken experiment is designedwith respect to 3 mentioned factors and 3 levels of each factor. The response surface method (RSM) is employedto determine the non-linear relation between the total cost as the response and the proportion of easydelignification, amount of Effective alkali in white liquor and Kappa number. To minimize the total cost, the optimalvalues of each factor are 75% of easy delignification, 112 grams per liter of Effective alkali in white liquor and13.5 of kappa number. Under this optimal condition, the average total cost per ton of Eucalyptus is 13,393.91Baht which is significantly less than the total cost of 15,517.06 Baht per ton before improvement.