IMPROVEMENT OF GALACTOMANNAN HEMICELLULOSE ON RUNNABILITY OF OFFSET NEWSPRINT PAPER MACHINE

Galactomannan(GM) is a heterogeneous polysaccharide hemicellulose, and has a cellulose-like structure resulting in high affinity to cellulosic fibers, which can be adsorbed onto the surface of fibers. Meanwhile, sorb fine cellulose fibers, mineral fillers and colloidal particles are present in fibre suspension at very low addition rate, and are thus regarded as a high-performance wet-additive in the papermaking process. In this study, effects of galactomannan hemicellulose on runnability of offset newsprint paper machine have been discussed via both lab trial and pilot plant. In the suspension of deinked old newspaper fibers pulp, only when a lower dosage of 0.3%similar to 0.5% (weight fraction) galactomannnan hemicellulose was added might the fiber, colloid composition and filler be bonded together, leading to a higher surface strength and a reduced risk of tinting and dusting on printing operation; the initial wet strength might also be increased by similar to 20% to improve the runnability of wire and press section, when increased strength and retention, and the micro-agglomeration conformation had a little effect on the drainage of pulp stock; the adsorption resulting from molecular association (i.e. hydrogen bond and Van der Waals force) was capable of retaining fine fibers, colloids and inorganics in the fiber web, and reduced the COD content of white water system of paper machine in favor of 'effluent free' demand of high-speed paper machine.