煤液化油加氢脱硫反应动力学研究

Study on hydrodesulfurization kinetics of coal liquefaction oil

固定床加氢精制对煤液化油具有明显的稳定和改质作用,研究煤液化油中含硫化合物分布形态与加氢脱除规律有利于推动煤化工清洁油品技术发展并实现煤化工产品技术升级,其动力学研究可为加氢反应器设计、新型催化剂开发提供理论指导。采用气相色谱-脉冲火焰光度检测器(GC-PFPD)对煤液化油进行不同类型含硫化合物组成分析,研究反应条件对加氢总脱硫率、不同类型含硫化合物脱除的影响,并基于加氢脱除速率差异对煤液化油的脱硫反应进行动力学研究。煤液化油中含硫化合物主要集中在苯并噻吩类和二苯并噻吩类化合物,其中二苯并噻吩类化合物占液化油中含硫化合物总量的54.45%。采用10 mL固定床加氢反应器对煤液化油进行加氢精制,研究加氢过程中反应条件对含硫化合物脱除效果的影响以及不同类型含硫化合物的脱除规律。结果表明:当空速为1 h^(-1)时,320℃条件下脱硫率达到了95.57%。硫醇、硫醚等化合物在较缓和条件下即可脱除完全,提高反应苛刻度主要针对二苯并噻吩类化合物加氢脱除。通过对噻吩类化合物、苯并噻吩类化合物与二苯并噻吩类化合物脱硫动力学分别进行研究,建立了基于混合组分差异加氢速率的煤液化油加氢脱硫反应动力学模型,匹配煤液化油组分特点且适用范围更广。通过验证可知,煤液化油加氢脱硫反应动力学模型的相对误差为0.59%,可为煤液化油加氢精制工艺设计提供理论指导。

It has obvious stability and modification effect on coal liquefaction by fixed bed hydrogenation.The research of distribution form and law of removal of sulfur-containing compounds in coal liquefaction is conducive to the development of clean coal chemical oil technology and implementation of technological upgrades for coal chemical products.The dynamics research of hydrofining can provide theoretical guidance for hydrogenation reactor design and new catalyst development.The composition of various sulfur-containing compounds in coal liquefication oil was analyzed by gas chromatography with pulse flame photometric detector(GC-PFPD).The impacts of reaction circumstances on the overall hydrodesulfurization rate and the removal of various types of sulfur-containing compounds were studied,as well as the kinetics of the desulfurization reaction of coal liquefaction oil based on the variety of hydrogenation removal rate.Benzothiophenes and dibenzothiophenes were the dominant sulfur-containing compounds in the coal liquefication oil,of which dibenzothiophenes accounted for 54.45%of the total sulfur-containing compounds.The influence of reaction conditions on the removal of sulfur-containing compounds,as well as the removal law of different types of sulfur-containing compounds,were investigated by hydrofining of coal liquefication oil in a 10 mL fixed-bed hydrogenation reactor.The results reveal that the desulfurization rate can reach 95.57%at 320℃when the space velocity is 1 h^(-1).The improvement of reaction severity is primarily aimed at the hydrogenation removal of dibenzothiophenes,as mercaptan,thioether and other compounds can be removed under moderate conditions.The desulfurization kinetics of thiophenes,benzothiophenes and dibenzothiophenes were studied respectively and a kinetic model for the hydrodesulfurization of coal liquefication oil was established,which matches the characteristics of coal liquefaction oil and is more applicable,based on differential hydrogenation rates of the mixed compounds.The relative error of kinetic model of hydrodesulfurization reaction of coal liquefaction oil is 0.59%by model verification,and therefore it can provide theoretical advice for hydrofining process design of coal liquefaction oil.