摘要：
以乙醇硫酸法从硫酸盐法制浆黑液中提取木质素,利用元素分析仪、氧弹式量热仪、热重分析仪和电子显微镜,对醇酸木素(CSL)中C、H、O元素的质量分数、燃烧热、热解特性及表面形貌进行测试与分析.结果表明:CSL的C、H、O元素的质量分数分别为62.55%,5.57%和29.53%,均较黑液和酸木素(SL)中的相应元素高;两种木质素的氢碳比(H/C)分别为1.057和1.068,均较黑液低很多.CSL的燃烧热为22.237 kJ/g,SL的燃烧热为21.591 kJ/g,均比黑液高;与SL和黑液相比,CSL更具有成为燃料的条件.CSL的热解过程分为水分散发阶段、脂肪键断裂阶段、醚键断裂阶段和解聚阶段4个阶段.CSL热解过程中出现两个质量损失峰,分别在350和369°C处,最大质量损失速率为13.0%/min,最后残渣质量百分比为35.48%.与SL相比,CSL热解速率快,且热解完全.与黑液和SL相比,CSL表面的空隙较多,粒径小,燃烧更为充分.利用乙醇硫酸法从造纸黑液中提取的木质素燃烧性能较单纯硫酸法提取的木质素及黑液燃烧性能优异.%Lignin was extracted from the black liquor of kraft pulping by using ethanol?sulfuric acid. The combustion and pyrolysis properties of extracted lignin(CSL)were studied by using elemental analyzer,oxygen bomb calorime?ter,thermogravimetric analyzer,and electron microscope. The contents of C,H,combustion heat,pyrolysis charac?teristics and surface morphology of the CSL were measured and analyzed. The results showed that the C, H and O contents were 62.55%,5.57% and 29.53%,respectively,which were higher than those of black liquor and acid lignin (SL). The hydrogen?carbon ratio of the CSL and SL was 1.057 and 1.068, which was much lower than that of the black liquor. The combustion heat of the CSL is 22.237 kJ/g, and that of the SL is 21.591 kJ/g, which was higher than that of black liquor,indicating the CSL has more potential used as fuel than the SL and black liquor do. The py?rolysis process of the CSL consisted of four stages including the water release phase,the fat bond breaking stage,the ether bond break stage and the depolymerization stage. There were two weight loss peaks in the pyrolysis of alkyd lig?nin at 350°C and 369°C. The maximum weight loss rate was 13%/min and the final percentage of residue mass was 35.48%. Compared with the SL,the CSL had a faster pyrolysis rate and more complete pyrolysis. Compared with the black liquor and the SL,the CSL surface had more voids,and the particle size was smaller,which also made the CSL burned more completely. The results indicated that the combustion performance of the lignin extracted from papermak?ing black liquor by ethanol sulfuric acid method is better than that of the lignin and the black liquor extracted by pure sulfuric acid method.
