Cu-Mg-Al催化剂催化甲醇裂解制氢的研究

Study on catalytic performance of Cu-Mg-Al catalyst for hydrogen production by methanol cracking

利用共沉淀法制备了一系列不同铜镁铝摩尔比的Cu-Mg-Al催化剂,并用于固定床上甲醇裂解制氢的研究。采用BET、XRD、H_2-TPR和CO_2-TPD等表征手段对催化剂的结构和物化性质进行表征,并分析其对甲醇制氢反应催化性能的影响。结果表明,以1∶2∶1的铜镁铝摩尔比制得的催化剂对甲醇裂解制氢反应具有较高的催化活性,可改善前驱体的结晶度,增大催化剂的比表面积,增强催化剂的可还原性和碱性,从而提高了甲醇裂解制氢的转化率和气体收率,并抑制了液相副产物的生成。使用该催化剂,在压力为1. 0 MPa、反应温度为280℃、体积空速为0. 5 h^(-1)的反应条件下,甲醇的转化率为99. 28%,气体收率为97. 75%,液相副产物质量分数为1. 25%,反应稳定运行180 h后催化剂未发现明显失活。

A series of Cu-Mg-Al catalysts with different Cu/Mg/Al molar ratio are prepared via co-precipitation method.Their catalytic performance for hydrogen production by methanol cracking is investigated in a fixed bed rector and their structure and physic-chemical properties are characterized by BET,XRD,H2-TPR,CO2-TPD,etc.The results show that Cu-Mg-Al catalyst with a Cu/Mg/Al molar ratio of 1 ∶2 ∶1 can enhance catalytic performance for hydrogen production by methanol cracking because it has an increased crystallinity of the precursor,a larger surface area,an enhanced reducibility and an improved alkalinity. The conversion rate of methanol can reach 99. 28%,the gas yield can achieve 97. 75% and the content of byproducts in liquid phase is as low as 1. 25% when the reaction is performed over Cu1Mg2Al1 catalyst under the reaction conditions that the pressure is 1. 0 MPa,reaction temperature at 280℃ and volume space velocity at 0. 5 h-1.After experiencing 180 h of reaction,the catalyst does not show deactivation in the system.