A study of the regeneration of fresh and aged SO_x adsorbers under reducing conditions

摘要

Sorption of SO_2 over a commercial SO_x adsorber was studied at a laboratory scale usign a fixed bed reactor.The adsorbent material contains mainly alumina,barium oxide and precious metals.Sulphates formed by SO_2 sorption are reduced by carbon monoxide or hydrogen in teh presence of water.the main species emitted during the reduction was H_2S.The species COS was emitted at a very low level when carbon monoxide was used as a reducing agent.The total removal of sulphur was not possible in the absence of water,the sulphur remaining bonded to platinum (or palladium) sites.The role of water is to hydrolyse these sulphides,leading to H_2S or COS.The species SO_2 was also emitted when an aged catalyst was used,without a loss of the catalytic reduction efficiency.After a first sequence adsorption-regeneration,the adsorption capacity was not affected and the second regeneration was more efficient.Such a SO_x adsorber can be placed upstream a NO_x adsorber to avoid posoning of this latter by SO_2.