TG-FTIR研究煤油共热解产物逸出行为

TG-FTIR study on escape behavior of products from co-pyrolysis of coal and residuum

煤油共液化过程中煤与重油先发生共热解,而后加氢转化为小分子产品。因此,阐明重油对煤热解逸出产物的影响规律是调控共液化产物组成的重要热化学基础。本研究采用TG-FTIR对比研究塔河渣油(AR)和淖毛湖煤(NMH)单独热解及其共热解过程,结合热解活化能计算,探索共热解过程中塔河渣油(AR)对淖毛湖煤(NMH)热解产物逸出产物的影响。结果表明,单独热解时AR先于NMH发生热解反应。两者1∶1(质量比)混合共热解时,相比于单独热解计算的理论值,最大失重峰温度前移7℃,失重率增加约3%,共热解平均活化能降低23.6 kJ/mol,表明AR率先热解会诱发NMH热解,降低热解反应能垒。TG-FTIR结果显示,AR产生的烷烃类自由基会与NMH热解产生的含氧自由基结合,形成醇、醚等烷基类含氧有机化合物,从而抑制煤中羧基转化为CO_(2)的过程。研究结果有助于揭示共液化反应过程中重油对煤液化产物组成的影响。

Coal and residuum are first co-pyrolyzed,and then hydrogenated into small molecule products during coliquefaction.Therefore,clarifying influence of residuum on coal pyrolysis performance is an important thermochemical basis for regulating the process.The co-pyrolysis behavior of atmospheric residuum(AR)and Naomaohu coal(NMH)were investigated by TG,TG-FTIR and distributed activation energy model.The results showed that the peak temperature of the maximum rate of weight loss for the co-pyrolysis process was reduced by 7℃ compared with the theoretical value calculated by weighted average of AR and NMH pyrolysis alone,while the weight loss increased by 3%,the average activation energy decreased by 23.6 kJ/mol.In addition,the peak area of alkyl O-containing functional groups such as alcohols and ethers increased,whereas those of CO and CO_(2) decreased,suggesting that AR had a positive effect on NMH pyrolysis.Meanwhile,alkyl radicals from AR decomposition would combine with O-containing radicals generated from coal pyrolysis,thus resulting in a decrease of CO and CO_(2) by inhibiting breakage of carboxyl groups.This work will provide a scientific evaluation basis for revealing the influence of residuum on composition of coal liquefaction product during co-liquefaction.