商品桦木片对杨木BCTMP生产线的影响及对策

The Impact of Birch Chips on Poplar BCTMP Production Line and Its Solution

因优质原料供应不足,某企业在杨木BCTMP生产线原料中添加了40%的商品桦木片。原料质量变更后,成浆抗张指数下降20.16%,松厚度下降3.90%。并且工艺调整空间有限,无法制备满足纸机需求的合格浆料,为解决此问题,对该进口生产线进行了技术改造,在两段预浸渍中加入一台双螺杆加压浸渍器,对混合木片进行均质化处理。使用新系统后,与原系统混合材的最优工艺相比,过氧化氢总用量降低14.15%,氢氧化钠总用量降低9.69%,所得浆料在较高游离度下,满足纸机对浆料的各项需求。对原料的均质化处理是解决原料结构波动对化机浆生产线稳定运行影响问题的关键。

Birch chips were added to the raw material of the poplar BCTMP production line to alleviate the shortage of raw material supply.A 20%reduction in the pulp tensile index and a 3.90%one in bulk were obtained after the addition.Moreover,it was impossible to produce qualified pulp by process conditions adjustment alone.The production line was updated with addition of a twin-screw pressure impregnator between the first-stage and the second-stage impregnation to homogenize the mixed wood chips.After the upgrading,the total dosage of hydrogen peroxide and sodium hydroxide were reduced by 14.15%and 9.69%respectively.The pulp met all the requirements of the paper machine at a higher freeness.The homogenization of raw materials is the key to mitigate the impact of fluctuations in the raw materials quality on the stability of the BCTMP pulp production line operation.