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1.
本文用微量差热天平(DTA-TG)和电子微量天平分别考察了裂化催化剂再生过程中焦炭和水的吸附-脱附作用。结果表明,焦炭脱附热为2350kJ/kg焦炭,占焦炭燃烧热的6.3%,比ESSO公司提出的11.5%低得多。在工业催化裂化过程中,催化剂在反应器和再生器之间循环运转时吸水-脱水量很小,对再生热效应计算的影响可以忽略,在工艺计算中可以不予考虑。  相似文献   

2.
对连续重整催化剂上生成的焦炭和反应器壁上的结焦,进行了TGA、TPO、XRD、HNMR、GC-MS、SEM、TEM等测试。发现两种焦炭的形貌、结构、组成和性能等方面存在很大差别,从而阐明了两种焦炭不同的形成机理。  相似文献   

3.
新建一套以CAHN2000型电子微量记录天平为核心的流动式热重反应装置,并应用该装置进行工业微球分子筛裂化催化剂CRC-1再生动力学研究。结果表明,温度在500~600℃、常压下氧浓度为10%~15.2%的反应条件下,再生反应在动力学区进行,焦炭燃烧速度与催化剂上焦炭含量和氧分压均成一级反应关系;由异丙苯或甲基环已烷生成的焦炭具有基本相同的燃烧性能。该装置具有灵敏度高、准确性好、操作简便等优点,可用于催化剂方面的多种研究。  相似文献   

4.
Zn/HZSM-5丙烷芳构化催化剂反应与再生过程的稳定性   总被引:1,自引:0,他引:1  
对分别用离子交换法和浸渍法制备的 Zn/ HZSM- 5丙烷芳构化催化剂 ,进行了反应与再生过程的稳定性研究。在固定床连续流动反应器上考察了催化剂的结焦行为 ,用NH3- TPD和 TG对结焦催化剂作了酸性、结焦量的测定 ,并进行了 TEM形貌表征 ,表明催化剂上的结焦是造成失活的主要原因。 5 2 0℃下的空气烧炭并不能使催化剂恢复到初始水平 ,但催化剂的芳烃选择性有所提高 ,而失活速率明显降低 ;二次再生的催化剂同一次再生的基本保持了相同的活性和选择性。对经历了 3次反应与再生后的催化剂进行了锌含量测定 ,表明锌的流失相当缓慢。  相似文献   

5.
生物质油催化裂解精制中催化剂上焦炭前身物的分析   总被引:3,自引:0,他引:3  
采用热重、红外、核磁等分析手段,对生物质油催化裂解精制中使用的催化剂HZSM-5上的焦炭前身物进行了表征。沉积在催化剂表面上的焦炭前身物主要是短链饱和烃类化合物,沸点200℃以下;催化剂内部的结焦前身物主要为芳香族碳氢化合物,这些化合物的沸程为350~650℃。  相似文献   

6.
用静态甲醇吸附法分别测定纯分子筛、担体及CRC-1裂化催化剂结焦前后孔分布。采用严继民等建议的方法计算中孔分布,试用MP法计算微孔分布。在计算机上进行数据处理,结果表明所用计算方法可行。CRC-1催化剂结焦量为2.47%时没有明显堵孔现象,分子筛及担作两部位都结有焦炭。  相似文献   

7.
用异丙苯裂解反应考察了Ti-ZSM-5分子筛的催化活性,发现裂解活性与Ti-ZSM-5中Si/Ti有关,Ti进入分子筛骨架降低了积炭活性,但焦炭的生成并不影响稳态活性,表明炭主要沉积在催化剂的外表面上。  相似文献   

8.
研究了炭化工况对木质素焦炭电阻率的影响,并结合拉曼光谱和XRD分析研究了温度和催化剂对焦炭结构和导电性能的影响.结果表明:炭化温度的提高和催化剂的添加有利于焦炭石墨化,即提高焦炭导电性能.添加催化剂需要采用两段炭化法以避免焦油对催化剂的中毒作用.随着温度的升高,拉曼光谱中D峰强度不断增加,产生的活性炭原子与焦炭中的灰分结合形成的离子络合物导致了电阻率的降低.添加催化剂使得D峰和G峰强度均有增加,说明催化剂可以促进焦炭的炭化和石墨化.镍基催化剂较容易使焦炭获得石墨化结构,在低温阶段催化效果明显.而铁基催化剂在高温下也可以体现出较强的催化能力.  相似文献   

9.
为了探讨结焦因素对乙炔水合磷酸镉钙催化剂稳定性的影响,本文应用石英弹簧秤在常压微分流动体系中,于300-420℃和250-450℃的温度范围内分别研究了乙炔和乙醛在这种催化剂上的结焦动力学行为.找出抛物线经验方程表达了乙炔的结焦动力学.认为过程吸附平衡迅速建立,吸附层的结焦分解为其控制步骤,并以多层沉积的焦上结焦机理和由于焦层扩散阻滞的影响而使结焦速度同焦量成反比的假设,讨论了经验方程式的物理意义.实验表明,乙炔催化水合伴随有强烈的乙炔和乙醛在催化剂上的焦化作用.乙醛缩聚的沉积物发现有进一步的脱羧分解过程.催化剂表面吸附的水分子能显著抑制催化剂的焦化作用.乙炔结焦活化能比水合活化能大约低10Kcal/mol的数量级.  相似文献   

10.
为解决高超音速飞行中喷气燃料的热裂解结焦问题,在连续流动反应装置上研究了结焦抑制剂二苄基二硒醚对RP-3喷气燃料超临界热裂解结焦的影响.结果表明,在RP-3中添加100×10-6二苄基二硒醚可降低结焦总量约达50%,裂解气的产量降低约20%,产物分布变化不大.SEM、TPO、EDS和XPS分析表明,高温下二苄基二硒醚与反应管表面铁原子形成金属硒化物,从而既抑制了纤维状焦炭的生成,又减少了无定形炭和富氢吸附炭的沉积量。  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.
<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   

20.
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