Perovskite Wire-mesh Honeycomb For Catalytic Combustion Of Air Diluted Methane

First,two kinds of composite powders of La_0.8Ca_0.2FeO₃?LCF?and La_0.8Sr_0.2MnO₃?LSM?with MgAl₂O₄?MgAl?were prepared by deposition-precipitation method.The activity of the composite powder was measured in the Temperature-Programmed Micro Reactor?TPRS?and properties characterized by XRD,BET,SEM,and TPR in an effort to optimize the molar ratio of LCF to MgAl,as well as the proper calcination temperature of the composite.It was found that after compositing with MgAl,the thermal resistance of LCF was improved substantially,and its activity almost doubled(from 508.8 to 508.7?quantified by T₅₀,with half amount of LCF).Compared with LCF,the improvement of LSM was even greater(from 582.7 to 483.7?quantified by T₅₀,with half amount of LSM)after compositing with MgAl,resulting in a composite powder with better activity.Then,the metallic wire-mesh honeycomb substrate modules were dip-coated sequentially by slurries of MgAl spinel and LCF/MgAl composite powders,respectively.The monolith was applied for catalytic combustion of air diluted methane?0.5vol.%?.Influences of the calcination temperature of the composite powder before ball-milling and loadings of MgAl and composite powder coatings were investigated.For comparison,the catalytic combustion of 0.5vol.%methane was carried out at GHSV of 40000 h^-1 for both wire-mesh and ceramic honeycomb catalysts,where the catalyst on wire-mesh substrate was proved to be48.1%more effective at 600?.Finally,the performance of the wire-mesh honeycomb was examined in a 500 hrs'time-on-stream test.The activity was dropped by20.3%in the initial 200 hrs,then stable for the remaining 300 hrs.