Study On Performance Of Hydrogen Removal From Tail Chlorine Catalyzed By Copper And Copper Oxide Catalysts At Low Temperature

Chlor-alkali industry plays an important role in the industrial development in China and even in the world.The development of China's chlor-alkali industry is advancing by leaps and bounds,and now the chlor-alkali production ranks first in the world.However,when the chlor-alkali industry began to develop there has been a problem of tail chlorine which,a mixture of chlorine gas including chlorine,nitrogen,oxygen,and hydrogen,is enriched when the chlorine is compressed and liquefied to prepare liquid chlorine and due to the risk of explosion,the presence of hydrogen?about 4%volume fraction?become the biggest potential safety hazard in tail-chlorine treatment.Therefore,researchers have been paying attention to how to safely and effectively remove the hydrogen in tail gas.The experiment prepared reaction gas according to the composition and content of tail chlorine in the industry that Cl₂ is 65%-80%,N₂ is 6-16%,O₂ is8%-10%,H₂ is 1.5%-4%.The experiment used fixed-bed reactor and cheap materials copper and copper oxide as a catalyst by catalytic hydrogen-hydrogen and hydrogen-chloride reaction to achieve the purpose of removal hydrogen safely and effectively.The following conclusions can be drawn from the experimental results:First.The catalytic selectivity of hydrogen-chloride is greater than that of hydrogen-oxygen when copper is catalyst.When the reaction temperature is110?and the copper mesh is 100-120 in the measurement range,the catalytic effect is best and the average conversion rate of hydrogen is 89.79%.The order of catalytic effect of copper mixed with aluminum and activated carbon and so on as catalysts is:alumina>water-absorbing resin>silica>activated carbon>molecular sieve.Second,the stability and catalytic performance of CuO/Al₂O₃ as catalyst in the removal of hydrogen from tail gas is superior to pure copper oxide catalyst.The catalytic effect of CuO/Al₂O₃ catalyst is best when the active component is8%,the calcination temperature is 550°C,and the reaction temperature is110°C that the average conversion rate of hydrogen is 90.03%,and the selectivity of catalytic hydrogen-chloride reaction is greater than that of hydrogen-oxygen reaction.Third,through the characterization of EDS,SEM and XRD to copper catalysts,it can be concluded that part of the copper catalyst is chlorinated into cuprous chloride after the reaction.For the supported copper oxide catalyst,Copper was found after loading than before loading by EDS,and the characteristic peak of the copper oxide was not detected after the XRD characterization analysis to the catalyst of after loading indicating that the copper oxide is highly dispersed on the support.The characterization of the SEM shows that the surface of the catalyst after the reaction is uneven and has traces of corrosion,therefor the characteristic peaks of copper chloride in the XRD characterization was found after the reaction of catalyst indicating that the active component in the supported catalyst is copper oxide and part of the copper oxide was chlorinated to copper chloride.In addition,N₂ adsorption and desorption characterization showed that there is no significant change in the pore size and surface area of the alumina-loaded copper oxide catalyst before and after the reaction indicating that the catalyst has a certain stability.