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1.
采用程序升温脱附(TPD)、透射电子显微镜(TEM)等方法,在柴油的裂化反应中,进行了镍沉积对分子筛催化剂的表面性质及催化裂化性能的研究。结果表明,在与工业操作相对应的水蒸汽作用条件下,随着分子筛催化剂上金属镍量的增加,催化剂的结构和性质将发生不同程度的影响,导致催化剂的裂化活性下降,脱氢生焦量增多;水蒸汽处理温度的升高,金属镍分散度降低,将部分地抑制和消除镍的脱氢生焦倾向。  相似文献   

2.
王涛  王继龙  林宏 《甘肃科技》2007,23(1):35-37
介绍了乙苯脱氢催化剂的制备方法和制备工艺改进历程,将LH365M催化剂与LH365、进口催化剂在物理性能和化学性能上作了对比,针对乙苯脱氢工艺的发展情况,提出了理想的乙苯脱氢催化剂制备工艺。结果表明:通过催化剂配方的调整、原料预处理的改进和催化剂制备工艺、设备的改进,催化剂的物理性能和化学性能有了明显的提高,在化学性能上已接近国际同类先进催化剂的水平。  相似文献   

3.
对共Y-15平衡剂进行了模拟工业条件下的不同温度、压力和时间的水蒸汽钝化处理,考察了其钝化效果,并与锑钝化剂的钝化性能作了比较。结果表明:经高温水蒸汽钝化后,氢产率、焦炭产率明显降低;汽油产率有所提高,微活性指数下降缓慢,其钝化效果无论是从活性还是选择性上都优于锑钝化剂。平衡剂经一定条件的水蒸汽处理后,可有效地抑制沉积在催化剂上的金属Ni的脱氢生焦性能,而本身活性不至于有明显改变。  相似文献   

4.
考察了反应温度,空速、压力及催化剂水蒸汽处理条件对石脑油在稀土HZSM-5分子筛催化剂上的非临氢芳构化制取高辛烷值汽油反应性能的影响.结果表明,反应温度和空速对催化剂的催化性能有明显影响而压力的影响不太明显,高温、低空速有利于非临氢芳构化反应,但其中高温会导致C+5收率变低.在相同处理时间(6 h)下,随着催化剂的水蒸汽处理温度的升高,其初始芳构化活性下降,但催化剂的芳烃产率随着水蒸汽处理温度的增加先提高后降低,550 ℃水蒸汽处理温度下,催化剂芳烃产率最高,为催化剂最适宜的水蒸汽处理温度.  相似文献   

5.
乙苯脱氢制苯乙烯Fe_2O_3-K_2O系催化剂的XPS研究   总被引:2,自引:2,他引:2  
对铈、钼助催的Fe_2O_3-K_2O乙苯脱氢制苯乙烯催化剂使用前后和工业用后卸下的样品作XPS研究,结果表明:用后催化剂中铁以Fe~(2+)和e~(3+)两种价态并存,表面上生成一定量羟基,反应条件下钾和氧化铁发生作用生成新相K_2Fe_2O_4,它也是活性相,表面钾被水蒸汽溶解随物料流动而迁移流失,钾的流失是失活的重要原因,还有结构因素的影响,在催化剂表面铈以CeO_2微晶存在,反应条件下部分被还原,因而增加了晶格氧的活动性和电子传递渠道,通过促进氧转移脱氢而使催化剂脱氢活性增加。  相似文献   

6.
考察Mo2V1M0.5Ox(M=Co,Zr,Nb,Bi,Ni,Fe,Mn,Al,Sb,P,Nd,Te)系列催化剂的丙烷氧化脱氢性能,其中,添加Co的催化剂表现出较好的催化活性和丙烯选择性.对催化剂的BET,XRD,H2-TPR和NH3-TPD表征结果表明,Co元素的添加,改变了催化剂的物相组成,氧化还原性和酸碱性质,从而提高了Mo2V1Co0.5Ox催化剂的丙烷氧化脱氢性能.  相似文献   

7.
采用碱土金属Mg对SiO2进行预处理后, 用浸渍法制备Cu-ZnO/MgO-SiO2催化剂. 研究不同质量分数Mg对催化剂的结构和性能的影响, 考察该催化剂对仲丁醇脱氢活性和选择性的影响. 采用XRD,TPD和TPR对催化剂进行表征. 实验结果表明, Mg的加入提高了Cu组分的分散度, 同时降低了催化剂表面的酸性. 调节合适的Mg质量分数可获得性能较佳的仲丁醇脱氢催化剂.  相似文献   

8.
分别在空气气氛中和在乙苯脱氢反应中测试了11号、无铬210、无铬XH—02等工业催化剂及其去钾样品的电导。所有样品的电导随着温度上升而上升。在空气气氛中脱氢催化剂的电导比相应去钾样品的电导大。但在乙苯脱氢反应气氛中,两类样品的电导行为相反。对比了两类样品对乙苯脱氢制苯乙烯的性能。脱氢催化剂在水蒸汽存在下,间歇注入氯苯时,其电导脉冲式地上升;注入硫化氢气体时,电导脉冲式地下降。去钾样品无相似规律性。文中讨论了上述实验条件下各样品所产生的种种电导行为的原因。  相似文献   

9.
采用微反应活性测试(MAT)装置,以正庚烷为原料在反应温度为550℃和液空速为10h-1下,考察了CRC-3裂化催化剂活性随水蒸汽处理时间的变化规律.模拟工业流化催化裂化(FCC)条件,制备了无机钒酸盐中毒的催化剂,进而对其活性进行考察.MAT活性评价数据表明,用水蒸汽处理CRC-3裂化催化剂12h以后,其活性趋于平衡;而使CRC-3裂化催化剂中毒的无机钒酸盐中钒含量高达0.5%时,催化剂活性将发生明显的变化.  相似文献   

10.
用组合法合成HxKzM0.76Mo11VPAs0.68Oy系列杂多化合物,以浸渍负载于多孔钛片上制成催化剂膜,在自制膜式反应釜中对环已烷进行催化脱氢生成苯的反应,探讨了Fe^3 ,Bi3 ,K^ 的加入对催化剂催化脱氢反应性能的影响。结果表明:Fe^3 ,Bi^3 ,K^ 的加入都能很好的提高催化剂的催化脱氢反应性能。特别是铋离子的加入,能大大的提高环已烷的催化脱氢生成苯的效果。组成为HxK0.37Bi0.76PVAs0.68Mo11Oy的杂多化合物膜催化剂对环已烷的催化氧化脱氢反应有着良好的催化活性。在适宜的条件下,环已烷的催化氧化脱氢最高收率可以达到25.8%。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

20.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

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