桉木化学机械浆碱木素热解特性初步研究

Pyrolysis Characteristics of Alkali Lignin from Eucalyptus Mechanical Pulping Waste Liquor

关键词:  APMP  碱木素  TG-FTIR  热解特性

Key Words:APMP  alkali lignin  TG-FTIR  pyrolysis characteristic

摘要:采用酸析法分离桉木碱性过氧化氢法（APMP）制浆废液中的碱木素，应用热重红外联用（TG-FTIR）分析方法对碱木素的热解特性进行初步研究，并对热解过程中挥发性产物释放规律进行追踪。热重分析（TG）结果表明，热解主要分为玻璃态转化、主要热解、残留物质缓慢分解3个阶段；傅里叶红外光谱（FTIR）分析结果表明，热解阶段可挥发性产物有H₂O、CO₂、CO、CH₄、酚醇类化合物和醛酮类化合物，反应时间在2000 s以后的高温阶段热解产物主要为CO和CO₂。其中，CH₄、醛酮类化合物、酚类和醇类化合物释放主要集中在300～600℃之间，且产率均较高。

Abstract:The alkali lignin was separated from eucalyptus alkaline peroxide mechanical pulping (APMP) spent liquor by acid precipitating method. Then the pyrolysis characteristics of the alkali lignin were investigated using a thermogravimetric analyzer (TGA) and the releasing mechanisms of main volatile products during pyrolysis were on-line measured by Fourier Transform Infrared (FTIR) Spectrometer. The TG results showed that the pyrolysis of alkali lignin could be approximately described by three stages, which included glass transition stage, main pyrolysis stage, and residue decomposition stage. The FTIR results indicated that H2O, CO2, CO, CH4, aldehydes and ketones, alcohols and phenols were the main volatile products at the main pyrolysis stages. CO and CO2 were main products after 2000 s. It was also obvious that CH4, aldehydes and ketones, alcohols and phenols were released concentrically in 300~600℃ with considerably high yield.