Abstract:
This research has the objective to determine the mixing formula of pulp with different brightness from the EOP and D1 stages to reduce the variation of the brightness of pulp sent to the paper mill during the changing period of dry pulp grades. This research uses the Design of Experiment technique with the response surface design type and the regression technique to find optimal mixing formula for each of the seven brightness levels to obtain the target brightness of 86% and the pH of 5.25. The mixing formulas are determined by the pulp mixing percentage and the sulfuric acid consumption. The experimental results reveal that when using higher EOP mixing ratio, the brightness decreases and the pH increases. Regarding the effect of the sulfuric acid, when increase the sulfuric acid, the brightness and the pH decrease. After implementing the optimal formula in the production line, the mean of pulp brightness is closer to the target and the brightness variation decreases without affecting the quality of other pulp grades.