反应条件对介孔Ni-CaO-ZrO_2催化剂上CH_4耦合重整反应性能的影响

利用并流沉淀法制备了介孔Ni-CaO-ZrO2催化剂,在该催化剂上考察了水蒸气重整(SRM)、CH4部分氧化(POM)和CO2重整(CDR)反应的不同耦合方式对CH4重整反应的影响,以及反应温度和气态空速对CH4三重整反应制合成气过程的影响。实验结果表明,与单纯的CDR反应相比,SRM-CDR耦合反应与CDR-POM耦合反应均具有明显的优势,前者侧重于产物分布的调节,而后者则对增强催化剂的活性和稳定性有重要意义。CH4三重整条件下催化剂失活的主要原因是复杂气氛条件下的晶相烧结;在反应温度为973 K、气态空速35.0 L/(h.g)、n(CH4)∶n(CO2)∶n(O2)∶n(H2O)=2∶1∶0.875∶0.50的条件下,催化剂上CH4转化率约为83%,产物合成气中n(H2)∶n(CO)约为2.00,且在反应10 h内催化剂活性稳定。

Influence of Reaction Conditions on Methane Coupling Reforming over Mesoporous Ni-CaO-ZrO2 Catalyst

A mesoporous Ni-CaO-ZrO2 catalyst was prepared by a co-precipitation method.The influences of reaction temperature and GHSV on the catalyst activities in H2O-CO2 reforming(SRMCDR),CO2-O2(CDR-POM) reforming and H2O-O2-CO2 reforming(tri-reforming) of CH4 were investigated.It was found that the SRM-CDR and CDR-POM processes were better than CO2 reforming(CDR).The product distribution for SRM-CDR is easy to adjust,and POM-CDR was is beneficial for improving the activity and stability of the catalyst.And the tri-reforming of CH4 has the advantages of both SRM-CDR and POM-CDR.The complex atmosphere in the tri-reforming process can result in the sintering of the catalyst,which leads to the catalyst deactivation.CH4 conversion and H2/CO mole ratio in the products can reach 83% and 2.00 respectively under the conditions of 973 K,GHSV 35.0 L/(h.g),and n(CH4)∶n(CO2)∶n(O2)∶n(H2O) 2∶1∶0.875∶0.50,and the catalyst is stable in the reaction for 10 h.