覆炭载体Pt-Sn催化剂脱氢活性及抗结焦性能的研究

以覆炭γ-Al2O3复合材料(CCA)为载体,制备了Pt-Sn/CCA系列催化剂,并对其脱氢活性进行考察,结果表明:Pt-Sn/CCA催化剂的脱氢活性与稳定性均优于以γ-Al2O3为载体的Pt-Sn催化剂;CCA载体上的覆炭量对于Pt-Sn/CCA的脱氢活性具有一定影响,催化剂中铂质量分数为0 7%时,在覆炭质量分数12 3%左右出现脱氢活性峰;同时,Pt-Sn/CCA催化剂具有较好的低温活性及抗结焦能力。这些结果显示,借助CCA载体可能为提高脱氢活性及抑制催化剂结焦失活开拓一条新途径。     

Cu/ZSM-5催化剂的表征及其环己醇脱氢性能

以制备的ZSM-5分子筛为载体,采用浸渍法制备了一系列Cu负载量不同的Cu/ZSM-5催化剂。采用X射线衍射、氢气程序升温还原、吸附氨气程序升温脱附和BET等方法对Cu/ZSM-5催化剂进行了表征,用H2-N2O滴定法测定了Cu金属的比表面积和分散度。以环己醇气相脱氢制备环己酮为探针反应对Cu/ZSM-5催化剂的催化性能进行了评价。实验结果表明,Cu负载量影响Cu物种在载体表面的状态和分布,Cu是环己醇脱氢反应的活性中心,其比表面积、分散度与Cu/ZSM-5催化剂的活性相关,Cu/ZSM-5催化剂的B酸中心与环己醇脱氢反应的选择性相关。Cu质量分数5%的Cu/ZSM-5催化剂上Cu金属的比表面积较大而B酸中心较少,显示出很高的环己醇转化率(58.7%)和较好的环己酮选择性(97.2%)。     

在V-Mg-O催化剂上丁烷氧化脱氢制丁二烯和丁烯Ⅰ.反应器的影响

采用惰性膜反应器（IMR）和固定床反应器（FBR）研究了V－Mg-O催化剂上丁烷氧化脱氢制丁二烯和丁烯的反应，采用在陶瓷膜上部分涂釉方法得到的惰性膜的渗透率符合实验要求，用多级全混流模型描述IMR中丁烷氧化脱氢反应，数学模型的计算结果与实验结果相差较小，分析了IMR和FBR中轴向气体分压，反应速率及瞬时选择性的分布，结果表明，用惰性陶瓷膜管作为空气分布器的膜反应器，可以降低丁烷氧化脱氢反应中催化剂床层的氧气分压，提高C4烯烃（丁二烯和丁烯）的选择性。     

新型高稳定性长链烷烃脱氢催化剂的研制

介绍了新型脱氢催化剂的研制和该催化剂H2化学吸附性能以及脱氢反应性能,讨论了助催化剂组分Sn和碱金属对催化剂活性、稳定性及选择性的影响。结果表明,新型催化剂的转化率比工业用DF-2催化剂高2个百分点,寿命和选择性与DF-2相当。     

羟基磷酸铜钙催化环已烷氧化脱氢反应研究

采用共沉淀法制备羟基磷酸铜钙（CCHP）,考察了CCHP催化剂在环已烷气相氧化脱氢反应中的催化性能。结果表明,该类催化剂只表现出深度脱氢活性,在所考察的温度范围内,催化剂活性和稳定性较好。催化剂进一步用正硅酸乙酯处理后,其表面变得更亲油,脱氢活性明显改善,600 ℃时,环已烷脱氢产物苯的收率可达25.6%。     

新型环己醇脱氢催化剂的制备及其与工业催化剂性能比较

以硝酸铜和高氯酸锆为原料,氢氧化钠为沉淀剂,采用共沉淀法制备了环己醇脱氢生产环己酮的新型Cu/ZrO2催化剂。通过正交试验确定了较优的催化剂制备条件为锆铜原子比为2,焙烧温度为500℃,焙烧时间为5 h,锆盐初始浓度为0.2 mol.L-1,滴定终点pH为12。优化条件下制得的催化剂在实验室中用于环己醇脱氢,环己醇收率达85%,选择性高于98%,优于目前该反应过程工业上所用的同类催化剂。     

DH-2型脱氢催化剂的使用及维护

介绍CO2汽提法尿素装置应用DH-2型脱氢催化剂的情况,包括脱氢原理、工艺操作指标、催化剂装填、运行中的注意事项、影响其活性的因素,以及异常情况的处理等。     

Effect of initial powder type on the hydrogen storage properties of high-pressure torsion consolidated Mg

While severe plastic deformation (SPD) on bulk samples has been widely applied for modifying the H-sorption properties, there has been little attention towards the use of SPD on powder materials. In this context, the aim of the present work was to compare the H-storage properties of high-pressure torsion (HPT) consolidated products obtained from two distinct Mg powder precursors: atomized micro-sized and condensed ultrafine powder particles. The results showed that the nature of the initial powder precursor had a pronounced effect on the H-sorption behavior. The HPT product obtained from the condensed ultrafine powder showed faster absorption kinetics than the consolidated product obtained from the atomized powder. However, the HPT product obtained from atomized powder could absorb more hydrogen and showed faster desorption kinetics corresponding to a lower activation energy. These results are discussed by taking into account the effectiveness of the HPT process to refine the grain sizes and differences in the dispersion of fine MgO oxide particles.     

Highly selective and stable bimetallic catalysts supported on different materials for n-butane dehydrogenation

A study about the performance of Pt(0.3 wt%)Sn(0.3 wt%) catalysts supported on different materials in n-butane dehydrogenation is reported in this paper. The materials used as supports were γ-Al₂O₃, ZnAl₂O₄ spinel, MgAl₂O₄ spinel and spheres of α-Al₂O₃ with a washcoating of γ-Al₂O₃. The syntheses of both spinels leaded to very pure ZnAl₂O₄ and MgAl₂O₄ supports. The material prepared by washcoating showed the presence of an uniform and homogeneous layer of γ-Al₂O₃ (with a thickness between 12 and 18 μm) deposited on the spheres of α-Al₂O₃.The best behavior in activity, selectivity and stability through five severe cycles was achieved by bimetallic PtSn catalysts supported on MgAl₂O₄ spinel and on the material prepared by washcoating. The very good performance of these catalysts through the different cycles of reaction-regeneration can be due to the presence of metallic phases which preserve the strong intermetallic interaction along the different treatments, thus avoiding segregation processes.