芦苇等非木材纤维原料KP法蒸煮过程中黑液污染负荷的变化

Pollution Loads of Sulfate Black Liquor from Reed and Other Nonwood Raw Materials

本文对芦苇、麦草、蔗渣、慈竹、龙须草和棉秆等几种较常用的非木材纤维原料,在 KP 法蒸煮过程中黑液污染负荷的变化进行了研究.研究结果表明,芦苇等蒸煮过程中黑液污染值的形成可分为两阶段.不同纤维原料的 SC(COD 比污染值)与 SB(BOD 比污染值)都有一定的差异.蒸煮条件对 SC 的影响并不显著。原科种类是 SB变化的较重要影响因素.黑液的 COD_Cr、BOD_s 污染负荷(CL、BL)与纸浆得率之间存在倒数相关关系.

Pollution loads of spent liquor from kraft pulping of the commonly used nonwood fiber materials have been studied.It shows that pollutants(expressed as CODer)are being formed in two different phases during the kraft cook.It is observed that most of the polluting compounds are formed at the early stage of cook before the digestion temperature reaches 150℃.Further elevation of the temperature and up to the end of the cook,less polluting com- pounds(as indicated CODcr measurements)are being noted BODs values for the pollutants formed in the above phases show comparatively little differences in tendency as detected by CODcr measurements. Specific COD(SC) and specific BOD(SB)are introduced in this paper to describe the responses of pollutants formed during the digestion process to CODcr and BOD_5 determinations.It has been found that both SC and SB de- pend highly on the fibrous species eooked and to a certain extent vary with the digestion parameters. A reciprocol relationship between CODcr Load(CL)and BOD_5 Load (BL) with pulp yield can be established. And,for black liquor from reed pulping,the following is being suggested: CL=135900×1/Y-1359[kg/t] BL=35400×1/Y-354[kg/t] Where Y stands for pulp yield.