【摘要】 用过渡金属氧化物Co2O3·xH2O取代铁铬催化剂中的Cr2O3,以硝酸法制备了用于大型合成氨工艺使用的不含硫的铁基无铬CO高温变换催化剂。控制铁盐溶液中Fe2+和Fe3+的比例能保证催化剂的主相是γ Fe2O3。Co2O3·xH2O的存在减缓了催化剂因受热引起烧结而导致的比表面积下降,提高了热稳定性。活性评价结果表明,所制备的催化剂有很好耐热性和活性。Co2O3·xH2O的加入量w(Co2O3·xH2O)从1%增加到5%,耐热15h后的低温活性从29 6%提高到了61 3%,证明Co2O3·xH2O是Cr2O3理想的替代物。更多还原

【Abstract】 A nonchromium and nonsulfur ironbased CO high temperature shift catalyst suitable for largescale ammonia technology was prepared through coprecipitation of nitrate salts by NH4OH.Transition metal oxide Co2O3·xH2O was used as catalyst promoter to replace noxious ingredient Cr2O3 in ironchromium catalyst.γFe2O3 used as the catalyst support was obtained by means of controlling Fe2+/Fe3+ ratio in the aqueous reactant.Owing to the action of Co2O3·xH2O,the decrease of specific area caused by sintering effect slowed down.When use level of Co2O3·xH2O increased from 1% to 5%(mass fraction),after resisting heat for 15 h, the low temperature activity of the catalyst increased from 296% to 613%.It was proved that Co2O3·xH2O was an ideal substitute for Cr2O3 because of providing the catalyst with a good heat resistance and high activity.更多还原