金属氧化物对霍林河褐煤催化热解行为的影响

Effect of metal oxides on catalytic pyrolysis of Huolin River lignite

选用4种金属氧化物(CaO、Al2O3、Fe2O3、NiO)作为催化剂对霍林河褐煤进行热解,利用热重分析技术和动力学模型对褐煤热解行为进行分析,研究不同金属氧化物对褐煤热解催化效果的影响。结果表明,4种金属氧化物催化剂的加入均能有效提高褐煤热解的转化率,其对褐煤热解转化率的促进作用顺序为:NiO>CaO>Fe2O3>Al2O3;在褐煤整个热解过程中,CaO、Fe2O3及NiO均表现出良好的催化作用,而Al2O3仅在热缩聚阶段有一定的催化效果;褐煤在活泼热解阶段和热缩聚阶段的热解过程分别可用一级单一反应模型和二级单一反应模型进行描述,4种金属氧化物在活泼热解阶段对褐煤的催化效果为:NiO>Fe2O3>CaO>Al2O3,在热缩聚阶段对褐煤的催化效果为:Fe2O3>CaO>NiO>Al2O3。

Four metal oxides (CaO,Al2 O3 ,Fe2 O3 and NiO)were selected as catalysts for the pyrolysis of Huolin River lignite.The pyrolysis behaviors of the lignite were analyzed by thermogravimetric a-nalysis technique and kinetic model.The effects of different metal oxides on the catalytic pyrolysis be-haviors of the lignite were investigated.The results show that the addition of any of these metal oxide catalysts can effectively improve conversion rate of the lignite pyrolysis,and their effects on the con-version rate of the lignite pyrolysis are NiO>CaO>Fe2 O3>Al2 O3 .CaO,Fe2 O3 and NiO have pro-motion effects for the whole pyrolysis process of the lignite,whilst Al2 O3 only shows a certain cata-lytic effect during the thermal condensation stage.The pyrolysis process during the active pyrolysis and thermal condensation stage can be described by the first-order reaction and second-order reaction model,respectively.The catalytic effect order of four metal oxides on the lignite pyrolysis during the active pyrolysis stage is NiO>Fe2 O3 >CaO>Al2 O3 ,while that during the thermal condensation stage is Fe2 O3>CaO>NiO>Al2 O3 .