Pentosan Extraction from Poplar Treated by Green Liquid

Green liquor, a process liquor of alkali recovery in pulp and papermaking industry, pretreatment used in poplar kraft pulping process and the influences of pretreatment conditions on pentosan extraction have been studied. The results show that the influence of green liquor dosage on pentosan extraction is the most remarkable, with temperature taking the second place and time the third. Under the conditions of liquor ratio 1:4, green liquor dosage 1.5 L/kg (based on oven dried material), temperature 100 °C, time 90 min, higher pentosan extraction ratio of 13.81% (based on the pentosan content of raw material) is achieved. The wood was pulped under normal KP conditions after pretreated by the optimal pentosan extraction conditions. Comparing two kinds of pulp with and without pretreatment at similar stock yield level, the results show that the former has a little lower viscosity, significantly decreased Kappa number and excellent paper physical properties.