共查询到20条相似文献,搜索用时 15 毫秒
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By means of XPS, ESR, DTA, and pyridine flash desorption techniques; micropulse reactor studies; and quantum-chemical calculations, it was shown that, during the coking of platinum-alumina catalysts in hydrocarbon media, the electron density of the platinum atom increases up to the formation of Pt0, which is a deactivating factor from the viewpoint of the electronic effects. The stabilization of the activity of platinum-alumina catalysts consists in an increase in the effective positive charge on the platinum atom; this function is fulfilled by modifier elements. It was found that the platinum protection mechanism differs, depending on the nature of the modifying additive: certain elements function via another, additional mechanism of catalyst stabilization, the blocking action. The theoretical conclusions made in this study are corroborated by the results of testing a new, Pt-Sb-Re catalyst supported on Al2O3-Cl with predicted properties. 相似文献
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固定床渣油加氢催化剂失活的原因分析及对策 总被引:1,自引:0,他引:1
固定床渣油加氢技术是重油改质的重要手段,是优化重油催化裂化装置原料的主要措施,而固定床渣油加氢装置催化剂的价格昂贵、使用周期短且不具再生使用性,因此探讨固定床渣油加氢催化剂失活的原因并采取相应的对策,对延长催化剂的使用周期有积极的意义。通过对固定床渣油加氢装置催化剂末期运行的现象、废旧催化剂化学组成等方面的分析,发现导致固定床渣油加氢装置催化剂失活的主要原因是积炭和金属沉积。同时分析催化剂级配装填的比例、催化剂硫化、原料油的性质和反应温度的分布等因素对固定床渣油加氢催化剂失活的影响,提出了采用抗积炭和容垢能力高的催化剂,进行合理的催化剂级配装填,控制好原料的性质,调整各床层反应温度的匹配分布和控制好催化剂开工条件等措施,可有效延长催化剂的使用寿命。 相似文献
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E. V. Asachenko O. V. Rodina V. V. Ordomskii Yu. V. Gur’ev I. I. Ivanova 《Petroleum Chemistry》2008,48(2):100-104
The specifics of the deactivation of acid and Zn-containing MFI catalysts in the propane aromatization reaction at high-feed space velocities (600–2400 h?1) and temperatures (550–610°C) was studied. The kinetics of the buildup of carbonaceous products (coke) was investigated in situ during the catalytic reaction in a thermal analyzer coupled to a mass spectrometer and a gas chromatograph (TA-MS-GC). The nature of the coke was studied by means of differential thermal analysis (DTA) and elemental analysis. It was found that the buildup of heavy coke on the H-MFI zeolite takes place on the outer crystal surface and pore openings, thus leading to a decrease in the propane conversion at the beginning of the reaction. In contrast, light coke appears first and is transformed to heavy coke at later stages on Zn/H-MFI. The light coke leads to a decrease in the yield of methane, ethane, and ethylene, and the heavy coke impedes the formation of aromatic hydrocarbons. 相似文献
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S. G. Prokopyuk E. D. Radchenko R. R. Aliev I. V. Egorov 《Chemistry and Technology of Fuels and Oils》1988,24(6):245-246
Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 6, pp. 14–15, June, 1988. 相似文献
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A five-lump kinetic model has been presented to describe the process of heavy oil hydrocracking, and tested in moderate condition. In the condition of low temperature and pressure relatively, coke formation can be controlled and the model is well applied with product distribution. In this paper, we explored the process of hydrocracking in slurry-phase by using dispersed catalyst at higher temperature and pressure, it was found that at the high residue conversion, the coke formation could be controlled even if the residue conversion is up to 90%. Then, a five-lump model by analytical method based on Monte Carlo technique was used to calculate the kinetic parameters, and the product distribution in the condition of high conversion was predicted successfully. 相似文献
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CH_4-CO_2重整制合成气Ni基催化剂的失活研究 总被引:2,自引:0,他引:2
CH4-CO2重整制合成气反应(MCR)中导致Ni基催化剂失活的主要原因可能有二:一是助剂组份碳酸化生成稳定碳酸盐物种毒化了反应活性位;二是笼状(包括石墨态和无定型态)炭的沉积覆盖了催化剂表面。MCR反应中炭的沉积主要有两种形式:一是以须状形式进行堆集,二是以笼状形式覆盖于催化剂表面,前者对于催化剂活性的保持似无明显影响,后者则是导致催化剂失活的主要原因之一。 相似文献
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Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 1, pp. 37–40, January, 1992. 相似文献
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可控震源技术使用误区分析 总被引:1,自引:1,他引:0
曹务祥 《石油地球物理勘探》2006,41(3):341-345
本文针对可控震源技术应用和参数选取的问题,重点讨论了垂直叠加、驱动幅度、扫描斜坡和激发能量等方面的问题,并提出了一些新的认识和建议。垂直叠加对时不变噪声不起作用,提高覆盖次数比提高震次更有利于压制噪声;驱动幅度增加到一定程度时,不一定能增加扫描信号的下传能量,而是增加了谐波成分;扫描斜坡对低频有压制作用,并能减少吉布斯现象;震动能量与扫描长度成正比,单位频率扫描能量与扫描频宽成反比。在可控震源的使用中,人们应克服凭经验选取参数的缺点,通过增强科学分析和定量计算选取参数。 相似文献
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A. Yu. Evdokimiv I. G. Fuks N. G. Zagorodnii 《Chemistry and Technology of Fuels and Oils》1990,26(11):569-578
Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 11, pp. 3–8, November, 1990. 相似文献