Energy saving in pulping

The purpose of slushing in recovered paper processing is to break down the raw material into individual fibers as much as possible to form a suspension that can at least be pumped. Tosaveenergy, the first step with the pulpers is limited to coarse slushing and heavy particle separation. Fine disintegration and coarse screening with the disk screen usually follows. The main advantage of the high consistency pulper with spiral rotor is economy of pulping energy and gentle slushing with low breaking down of contaminants. It was developed the equation determining the power required by the helical rotor for circulating of a stock in a pulper vat. To avoid excessive energy use, the impeller operating rotational speed as well as the power of the motor should be adequate for good disintegration but have the least possible value. To this effect was applied frequency converter. Energy efficiency of pulping represent the specific energy consumption expressed as kWh/t. The intensity of the slushing, kW/m3, is described by comparing consumed power to the vat filling volume.