Study Of Pectinase Combining With Chemical Additives To Control DCS In HYP

In recent years, papermaking industry have come to rely increasingly on high yield pulp (HYP) which mainly includ bleached chemithermomechanical pulps (BCTMP), alkaline peroxide mechanical pulp (APMP), preconditioning followed by refiner chemical treatment alkaline peroxide mechanical pulp (PRC-APMP). However during the pulping and bleaching, a variety of wood components are released into the paper mill process water. These components are termed dissolved and colloidal substances (DCS), and include a wide variety of chemical species such as lipophilic extracts, pectic acids, colloidal lignin, dissolved hemicelluloses et al. Because of white water recirculation and reuse, various DCS will accumulate in the mill process water systems. Many of these DCS substances are detrimental to both the papermaking wet end process and the quality of the resulting paper products. Therefore, there is a significant economical incentive to develop some practical strategies to control and treat DCS in white water.Pectinase treatment can decrease the cationic demand in a certain extent, and the addition of chemical additives could destabilize DCS, and decrease the cationic demand of HYP effectively. In this paper, poplar APMP and BCTMP were used as raw materials, and pectinase and chemical additives were used to treat DCS in pulp suspension.Pectinase could decrease the cationic demand of HYP, the degradation of pectinase to the pectin and their effect on cationic demand were analysised by GC-MS chromatography and PCD.For the treatment of BCTMP by combining pectinase with chemical additives, at the conditions of the dosage of alkaline pectinase1U/g pulp、talc5%、HCS0.5%、 CPAM0.01%, cationic demand decreased by42.59%with the sequence of adding pectinase first chemical additives second, and cationic demand decreased by49.23%with the adverse sequence.For the treatment of APMP by combining pectinase with chemical additives, at the conditions of the dosage of alkaline pectinase1U/g pulp、talc3%、HCS0.5%、 CPAM0.01%, cationic demand decreased by52.00%with the sequence of adding pectinase first chemical additives second, and cationic demand decreased by55.79%with the adverse sequence.At last the costs of pectinase and the chemical additives used for treatment of HYP were calculated, and it spends just about80yuan, so there is a good application prospect.