A Study On Monolith Catalysts' For The Catalytic Combustion Of Lean Methane

As to low concentrated methane of huge flow and low concentration, catalytic combustion is one of the best ways to resolve,and the exploitation of catalyst is the key point and crucial technique for methane catalytic combustion.This text which aims at the catalytic combustion of low concentrated methane,researches the monolith catalysts that take noble metal as active component,Ce,Zr as additives,cordierite and Al₂O₃ as the first and second carriers.We also have investigated the influence of the catalyst different preparation conditions on performance of methane catalytic combustion catalysts,using BET,XRD,TPR and SEM etc to analyze different catalyst samples.At the same time,we also have carried elementary study on reactive mechanism and activation vanishing mechanism of Supported Pd-Catalyst.First of all,we have investigated the influence of acid treatment on the activity of methane catalytic combustion.The conclusion shows that acid treatment can increase the BET surface area,pore volume,and the mesopore, micropore,and loading content,and it can also improve performance of methane catalytic combustion. Secondly,we have investigated the influence of Pd loading content, transition-mucus loading content and the content of rare-earth additives on the activity of methane catalytic combustion.The result indicates that quantity supported Pd and transition-mucus loading content separately takes up 0.5% and 10%of the catalyst quality is proper.While the content of CeO₂,ZrO₂ and Ce_xZr_1-xO₂ accounting for 5%of coating's quality is the best.The experimental results still indicate that adding additives can improve the PdO dispersive appearance and oxidative function in the catalyst,and raise the activity of the catalyst.Adding different additives vary the activity of the catalyst,5%CeO₂ behaves best.With the reduction of x in the Ce_xZr_1-xO₂ (x=0～1),the catalyst activity descends continuously,and 5%ZrO₂ catalyst behaves the worst.Thirdly,we have investigated the influence of calcination temperature and deoxidant on the activity of methane combustion catalyst.The outcome indicates that when calcination temperature is higher than 500℃,catalytic activity reduced obviously.Furthermore,the catalyst deoxidized by hydrazine hydrate can improve the activity of methane catalytic combustion.Finally,we have investigated the influence of noble metal Pt on the activity of methane catalytic combustion.We also have studied Pt-Pd double metal catalyst' producing process,and examined catalytic activity of single Pd catalyst,single Pt catalyst and Pt-Pd double-rare mental catalyst as well.The result indicates that Pt,Pd immerses together makes the activity of the catalyst higher than that immersed step by step.Pt-Pd double metal catalyst' activity is higher than single Pd and single Pt catalyst.