复杂多相体系煤加氢液化反应与氢传递的研究

研究新疆淖毛湖煤(NMH)在四氢萘为溶剂条件下的加氢液化反应行为,探究了液化过程氢传递规律,并借助XRD、饱和磁化强度和扫描电镜表征手段,研究了煤液化条件下铁系催化剂的相态变化对煤液化性能的影响。结果表明,NMH煤在420℃、17 MPa就具有良好的液化效果;催化剂的活性态Fe7S8在煤液化反应初期发挥了催化作用,加氢液化后期,转变为非活性态Fe_9S_(10)和FeS;提高催化剂加氢活性并延长反应时间有利于沥青烯和前沥青烯加氢轻质化;催化剂有利于活化气相氢向煤的热解产物和溶剂转移,也有利于活化溶剂中的氢向煤的热解产物转移;溶剂对液化反应的活性氢贡献更大,约为气相氢的两倍,气相氢向溶剂传递的氢量随温度的升高、压力的增大和时间的延长变化不大,气相氢和供氢溶剂供氢与煤和沥青质向油气转化呈正相关。

Reaction and hydrogen transfer in complex multi-phase system during coal hydro-liquefaction

Reaction behavior of Naomaohu (NMH) coal in tetralin was carried out under atmosphere of H₂. Hydrogen transfer in complex multi-phase system of direct coal liquefaction were discussed. The influence of phase transition process of iron-based catalyst on liquefaction performance was investigated using X-ray diffraction, saturate magnetization and scanning electron microscope. The results show that NMH coal presents good liquefaction performance at 420℃ and 17 MPa. Active phase Fe₇S₈ plays catalytic role during initial reaction and changes into nonactive phase-Fe₉S₁₀ and FeS later. High hydrogenation activity of catalyst and long residence time are beneficial to hydrogenation of preasphaltene and asphaltene into light oil. Catalyst promotes the activation of H₂ transferring to coal pyrolysis products and solvent. Catalyst promotes the hydrogen in solvent to transfer to coal pyrolysis products as well. The contribution to activated hydrogen from solvent is twice as that from H₂ in the condition of the experiment. Hydrogen transferring from H₂ to solvent changes little with temperature, pressure and time. Activated hydrogen from H₂ and solvent is proportional to the conversion of coal and asphaltene to oil and gas.