Selected physical parameters of spruce chips vs. alkali consumptions in the impregnation step of kraft pulping

Abstract

The uniformity of pulp and the amount of rejects are influenced by many factors, but impregnation can be the most important. The opportunities for improving impregnation of kraft white liquor start in description of the parameters affecting the process. The first parameter is the chip itself (its basic density, moisture, and pH) and the second is the process parameters set by the technological possibilities of the digester. During outside storage, the chips deteriorate via the fungal stains, brittleness, and high acidity. The moisture content also decreases. Understanding the relationships of chip parameters in the impregnation step and amount of rejects requires the assignment of effective alkali consumption. This study shows the effects of selected physical parameters, such as bulk density, moisture, and pH, of spruce chips on alkali consumption during impregnation step of a Super Batch process.