Research progress on deactivation mechanism and its improvement method of CO catalyst in steel gas
The composition of steel sintering gas is complex,which can easily lead to the decline of CO catalyst activity,so inhibiting catalyst deactivation and prolonging catalyst life are the key problems that need to be solved urgently.The deactivation mechanism of CO catalyst and its improvement process are reviewed,the mechanism of action of various toxic substances and their influence on CO catalytic reaction are introduced,the deactivation mechanism of the catalyst is explored and corresponding prevention or recovery measures are proposed.Catalyst deactivation mainly includes chemical poisoning,binder barrier,high temperature inactivation,water vapor poisoning,gas-solid reaction failure,and mechanical wear.The results show that the carbon deposition,coking and hydration reactions are easy to poison on the surface of the catalyst,and an inert overburden is formed to block the reaction.Long-term high-temperature reaction can easily lead to consolidation on the surface of the catalyst;in the gas-solid reaction,oxygen or chlorine will react with the metal activity to form volatile oxides or chlorides into the gas phase,causing material loss.In addition,the use of air flow blowing or catalytic bed stacking extrusion will reduce the pore structure strength,cause particle fragmentation and dusting,and affect the life of the catalyst.Precious metal consumption can be reduced by dispersing gold and silver precious metals on the surface of alumina or other non-precious metal carriers.Precious metals maintain a stable and highly dispersed state in high-temperature heat treatment,which will form nanoparticles on the surface of the catalyst,and synergistically interact with transition metals to cause lattice distortion and construct active sites,thereby improving the activity and stability of the catalyst.Rotation of catalysts involved in the reaction through process design is the main means of active regeneration.The replaced waste catalyst is sent into the regeneration system to clean the deposited coke that blocks the pore channel and the toxins that occupy the site by washing and blowing,which can eliminate the obstacle to the CO catalytic oxidation system.
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