2种木质素的醇热反应条件研究

以华燕醇溶碱木质素和TCI脱碱木质素为原料，在180～300 ℃的亚/超临界乙醇中转化为油、炭和气体产物，研究反应温度、反应时间和无机添加成分对产物分布和油炭化学结构的影响。结果表明：随着醇热反应温度从180 ℃升高到300 ℃，木质素原料通过裂解、重整和脱烷氧基等反应转化为了饱和脂肪链浓度增大、芳烃成分减少的生物油和以H₂和烃质气体为主的气体产物，生物油的产率先降低后升高；超临界条件增强了乙醇参与反应的活性，促成气体产率急速升高；在260 ℃反应时间延长到5 h之后，油和气体的产率急速上升，可能与反应残渣的催化作用相关，但是对于木质素成炭影响不大；而H₂SO₄和Na₂SiO₃催化均对2种木质素通过醇热反应产油产气带来了不利影响。

Comparative Study on the Alcohothermal Degradation of 2 Lignin Feedstocks in Sub-/Supercritical Ethanol

Huayan alcohol-soluble alkali lignin and TCI dealkali lignin as raw materials were converted into oils, chars and gas products at 180−300 ℃ with sub-/supercritical ethanol. The effects from reaction temperature, reaction time and inorganic additives on the product composition and the chemical structure of bio-oils and bio-chars were studied. The results showed that as the reaction temperature increased from 180 ℃ to 300 ℃, lignin feedstocks were cracked, reformed and dealkoxylated to produce bio-oils with increased concentration of saturated aliphatic composition and less aromatic compounds, while gas product mainly composed of H2 and gaseous hydrocarbons was also detected. The yield of bio-oil was firstly decreased and then increased with temperature. The activity of ethanol taking part in the reaction was enhanced under supercritical condition, which contributed to the rapid increase in gas yield. When the reaction time at 260 ℃ was extended to longer than 5 h, the yield of oil and gas rose rapidly, which might be related to the catalytic effect of solid carbonaceous residue, but had little impact on the formation of biochar. The addition of H2SO4 and Na2SiO3 provided adverse effect on the production of oil and gas during alcohothermal reaction.