沉淀pH对共沉淀制备ZnCr_(2)O_(4)及其合成气一步法制烯烃反应性能的影响  

Effect of precipitation pH of ZnCr_(2)O_(4) on catalytic performance in directing conversion syngas to light olefins

作　　者：尚蕴山 李民 韦慧 袁德林 刘华 刘意 邢爱华 SHANG Yunshan;LI Ming;WEI Hui;YUAN Delin;LIU Hua;LIU Yi;XING Aihua(National Institute of Clean-and-Low-Carbon Energy,Beijing 102211,China;China Shenhua(Baotou)Charcoal Chemical Industry Co.,Ltd.,Baotou 014060,Inner Mongolia,China)

机构地区：[1]北京低碳清洁能源研究院,北京102211 [2]神华包头煤化工有限责任公司,内蒙古包头014060

出　　处：《天然气化工—C1化学与化工》2022年第6期39-45,共7页Natural Gas Chemical Industry

摘　　要：合成气一步法制取低碳烯烃是一条极具发展潜力的非油基资源转化利用途径。金属氧化物与分子筛之间的“亲密性”可影响双功能催化剂中金属氧化物与分子筛之间的耦合效应,进而影响催化剂的催化活性。通过控制共沉淀法制备ZnCr_(2)O_(4)时的沉淀pH,获得了不同晶粒尺寸、团聚态的ZnCr_(2)O_(4)。结果表明,沉淀pH的变化不仅影响ZnCr_(2)O_(4)的结构组成、晶粒尺寸及其还原性,而且对ZnCr_(2)O_(4)与SAPO-34分子筛之间在介观上的“亲密性”效应也有显著的影响。沉淀pH为6.5~7.0时制备的ZnCr_(2)O_(4)具有良好的分散性,更容易与SAPO-34分子筛充分混合,ZnCr_(2)O_(4)与SAPO-34分子筛耦合更加紧密。ZnCr_(2)O_(4)/SAPO-34双功能催化剂(BS-6.5)在合成气一步法制烯烃反应中表现出最高的CO转化率(25.00%),其C_(2)=~C_(4)=选择性74.05%。Catalytic conversion of syngas to light olefins to be seen as potential routes for conversion and utilization of non-oil-based resources.The coupling effect between metal oxides and zeolites in bifunctional catalysts is closely related to the“proximity”,which in turn affects the catalytic activity of catalyst.ZnCr_(2)O_(4) with different particle size and aggregates were prepared by controlling the precipitation pH during co-precipitation process.The results show that,precipitation pH value not only affects the crystal structure,crystalline size and reducibility of ZnCr_(2)O_(4),but also affects the mesoscopic“proximity”effect between ZnCr_(2)O_(4) and SAPO-34 zeolite.The ZnCr_(2)O_(4) prepared at pH from 6.5 to 7.0 shows excellent dispersibility,which is easier to mix with SAPO-34 zeolite uniformly,leading to a higher proximity between ZnCr_(2)O_(4) and SAPO-34 zeolite.The ZnCr_(2)O_(4)/SAPO-34 bifunctional catalyst(BS-6.5)exhibits the highest CO conversion(25.00%)in one-step conversion of sy ngas to light olefins reaction and its C_(2)=~C_(4)=selectivity is 74.05%.

关 键 词：合成气 低碳烯烃 pH ZnCr_(2)O_(4) 耦合效应 双功能催化剂 

分 类 号：TQ241[化学工程—有机化工] O643.36[理学—物理化学]