THE INFLUENCE OF PROCESS PARAMETERS ON BROWN STOCK PULP WASHING
AT NATRON-HAYAT MAGLAJ

Brown stock washing is one of the major unit operations within the pulp manufacturing business.
Poor operating washers have the potential to significantly and negatively affect almost every other area of a pulp and paper mill, including the mill’s environmental performance. The objective of the pulp washing is to remove the soluble impurities such as organic solids (lignin), fines, inorganic solids (Na, Mg, Ca, and K ions), and byproducts after each processing step. The present paper attempts to look
at various parameters influencing pulp washing at Natron-Hayat Maglaj to ensure a complete understanding of the process. The results showed for this mixture of raw materials (15 % pine and 85 % fir) that the most influential parameters are Kappa number and dilution factor. Working with a high Kappa number above 50 requires additional equipment. Online control of the dilution factor would further improve the quality of the washing process and provide additional saving water and savings at the Evaporation plant. The First step for the future to improve the washing of unbleached kraft pulp is the optimization of the washing process through advanced control.