Study On Deep Removal Of Thiophene From Hydrogen By Adsorption

Under the background of"carbon neutral"and"carbon peak",China has increased support for proton exchange membrane fuel cells.The quality of hydrogen is one of the key factors determining the life of fuel cells.China’s industrial hydrogen production wide sources,large output,at the same time,hydrogen containing trace sulfur compounds,through the traditional method of pressure swing adsorption can only be easy to removal of organic sulfur and inorganic sulfur removal,residual sulfur content in the vast majority of is more difficult to removal of thiophene,the existence of traces of thiophene results in proton exchange membrane fuel cell toxicity,battery system.Therefore,the study on the removal of trace thiophene in hydrogen has very important practical significance and broad industrial application prospects.In this paper,activated carbon（AC）,13X molecular sieve,Na Y molecular sieve and ZSM-5 molecular sieve were selected as adsorbent carriers,and hydrogen containing thiophene was used as feed gas to evaluate the adsorption performance of thiophene in a fixed-bed reactor.means to characterize the carrier.The results showed that the AC support had the highest adsorption performance for thiophene,with a penetrating sulfur capacity of 1.76%,a specific surface area and a micropore volume of718.99 m²/g and 0.25 cm³/g,respectively.Secondly,using AC as the adsorbent carrier,various metal salts were loaded on the pretreated AC by the equal volume impregnation method,and the adsorption of thiophene in hydrogen by a series of prepared adsorbents was investigated in a fixed bed reactor.The prepared adsorbents were characterized by BET,SEM/EDS and XRD.The results showed that when Cu（NO₃）₂ was used as the copper source,the immersion time was 12 h,and the copper loading was 3.0 wt%,the prepared 3Cu/AC adsorbent had the highest breakthrough sulfur capacity of 3.31%.Cu（NO₃）₂ exists on the AC surface in the form of Cu O after calcination at high temperature.Compared with AC,the specific surface area,average pore diameter and pore volume of the copper-modified adsorbent are reduced.Thiophene forms complexes throughπ-bond coordination,thereby improving the desulfurization performance of the adsorbent.Finally,in order to further improve the sulfur capacity of the adsorbent,taking3Cu/AC adsorbent as the research object,a series of adsorbents modified with acid additives were prepared by the equal volume impregnation method.The adsorption performance was evaluated by using BET,SEM/EDS,XRD,FT-IR and other characterization methods to characterize the adsorbents with better thiophene removal performance.The results show that the specific surface area and pore volume of the adsorbent modified with citric acid are reduced compared with Cu/AC;citric acid promotes the dispersion of the active component Cu O on the adsorbent surface and improves the utilization of Cu O It also increases the acidic oxygen-containing groups on the surface of the adsorbent,the acid-base interaction between thiophene and the acidic groups is enhanced,and the adsorption performance of the adsorbent for thiophene is improved.Under the conditions of reaction temperature of 30°C,reaction pressure of 0.1 MPa,and reaction space velocity of feed gas of 1000 h^-1,the breakthrough sulfur capacity of 3CA-3Cu/AC adsorbent was 3.91%.