焙烧温度对镧改性HZSM-5表面性质及乙醇脱水制乙烯反应性能的影响  

Effect of Calcination Temperature on Surface Properties and Catalytic Performance in Dehydration Ethanol to Ethylene of La-Modified HZSM-5

作　　者：成源海[1] 张红漫[1] 胡耀池[1] 黄和[1] 应汉杰[1] 胡燚[1] 

机构地区：[1]南京工业大学材料化学工程国家重点实验室,江苏南京210009

出　　处：《中国稀土学报》2010年第3期330-334,共5页Journal of the Chinese Society of Rare Earths

基　　金：国家高技术研究发展计划项目(2006AA020101);国家科技支撑计划重点资助项目(2006BAE02B04)

摘　　要：采用浸渍法将稀土金属La负载在HZSM-5分子筛上,考察了在450-600℃范围内焙烧温度对La改性HZSM-5（La/HZSM-5）表面性质及催化乙醇脱水制乙烯性能的影响。X射线衍射和N2吸附-脱附分析分别表明焙烧温度对La/HZSM-5的晶体结构和孔结构影响不大,而NH3程序升温脱附测试则表明随着焙烧温度的升高La/HZSM-5的表面酸量和酸强度均有明显下降的趋势,相应的催化性能测试表明催化剂的活性和寿命也随之下降,这可归结于不同焙烧温度下La物种形态差异的结果。以450℃下焙烧制备的3%La/HZSM-5为优选催化剂,在最佳的反应条件下,其单程使用寿命可达108天。A series of La/HZSM-5 catalysts were prepared by impregnating the HZSM-5 zeolite with lanthanum nitrate solution.The effect of calcination temperature between 450 and 600 ℃ was investigated on the surface properties and catalytic performance in dehydration of ethanol to ethylene of these catalysts.According to XRD and N2 adsorption-desorption measurements,it was shown that calcination temperature had little influence on crystal structure,specific surface area and pore volume of La/HZSM-5.While NH3-TPD results indicated that the surface acid quantities and strength of La/HZSM-5 were significantly decreased as calcination temperature rose and their catalytic performance and lifetime also reduced.It might be attributed to different existence of La species under different calcination temperatures.The optimized catalyst was 3%La/HZSM-5 calcined at 450 ℃,whose single pass lifetime could reach 108 d at its optimal reaction conditions.

关 键 词：镧 HZSM-5 焙烧温度 乙烯 

分 类 号：O643.3[理学—物理化学] TQ221.21[理学—化学]