Development of a new hydrodemetallization catalyst for deep desulfurization of atmospheric residue and the effect of reaction temperature on catalyst deactivation

2005 ◽  
Vol 104 (1) ◽  
pp. 76-85 ◽  
Author(s):  
Takeshige Takahashi ◽  
Hidehiro Higashi ◽  
Takami Kai
Keyword(s):  
Reaction Temperature ◽  
Catalyst Deactivation ◽  
Deep Desulfurization ◽  
Atmospheric Residue

Removal of Thiophene from Simulated Oil by Catalytic Oxidation Using K2FeO4/ V2O5

2011 ◽  
Vol 183-185 ◽  
pp. 1568-1572
Author(s):  
Yan Xiu Liu ◽  
Hua Song
Keyword(s):  
Reaction Time ◽  
Catalytic Oxidation ◽  
Sulfur Content ◽  
Reaction Temperature ◽  
Temperature Reaction ◽  
Optimal Conditions ◽  
Catalyst Amount ◽  
Deep Desulfurization

Oxidation extraction of thiophene from simulated oil by using K2FeO4as oxidant and methanol as extractant has been investigated. The effects of different catalyst, oxidant amount, catalyst amount, reaction temperature, reaction time, and extraction conditions were studied. This process is capable of decreasing the sulfur content of simulated oil from 100 mg•L-1to 17.8 mg•L-1at the optimal conditions. The results indicate that such a process could be an alternative to common hydrodesulfurization for deep desulfurization.

Distribution and Conversion of Sulfur in Residue Thermal Reaction

2012 ◽  
Vol 524-527 ◽  
pp. 1792-1797
Author(s):  
Wen Long Cui ◽  
Wen An Deng ◽  
Rong Zhuo ◽  
Dong Liu ◽  
Chuan Li ◽  
...  
Keyword(s):  
Reaction Temperature ◽  
Thermal Reaction ◽  
Desulfurization Rate ◽  
Variation Trend ◽  
Atmospheric Residue ◽  
Reaction Severity

Lungu atmospheric residue (LGAR) was separated systematically to analyze the distribution of sulfur in subfractions. Based on this, the distribution and conversion of sulfur in products and residue subfractions were investigated at different thermal reaction temperatures. The result shows that the sulfur in each subfraction of LGAR had the same polarity and distribution tendency as corresponding fraction. At the same thermal reaction temperature, the distribution of sulfur in LGAR was in the descending order of aromatics, asphaltenes, resins I, resins II and saturates, which was similar with the distribution of sulfur before thermal reaction. In addition, a relatively uniform variation trend was found between each subfraction and its sulfur in LGAR thermal reaction, suggesting that the conversion of sulfur in LGAR was accompanied with the cracking and condensation of subfractions during thermal reaction. Moreover, the desulfurization rate of LGAR increased from 55.24% to 69.24%, while the desulfurization rates of LGAR subfractions were at the range of 45%-90% after thermal reaction. The desulfurization rates of both LGAR and subfractions increased with the reaction severity.

scholarly journals Effect of Operating Conditions on the Performance of Rh/TiO2 Catalyst for the Reaction of LPG Steam Reforming

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 374
Author(s):  
Aliki Kokka ◽  
Theodora Ramantani ◽  
Paraskevi Panagiotopoulou
Keyword(s):  
Reaction Temperature ◽  
Steam Reforming ◽  
Catalyst Deactivation ◽  
Space Velocity ◽  
Catalytic Performance ◽  
Operating Conditions ◽  
Propane Conversion ◽  
Liquefied Petroleum Gas ◽  
Steam Content ◽  
Tio2 Catalyst

The catalytic performance of Rh/TiO2 catalyst was investigated for the reaction of Liquefied Petroleum Gas (LPG) steam reforming with respect to the operating conditions employed. The impacts of reaction temperature, steam/C ratio, Gas Hourly Space Velocity (GHSV), and time were examined and discussed both in the absence and presence of butane in the feed. It was found that the catalytic performance is improved by increasing the reaction temperature, steam content in the feed, and/or by decreasing GHSV. In the presence of butane in the feed, the effect of H2O/C ratio on catalytic performance is prominent, whereas the opposite was observed for the effect of GHSV. The propane conversion curve decreases by adding butane in the feed, indicating that the presence of butane retards propane steam reforming. The investigation of the dynamic response of Rh/TiO2 catalyst to variations of H2O/C ratio showed that neither catalytic activity nor product selectivity is varied with time following abrupt changes of the steam/C ratio between 2 and 7. The catalyst exhibited excellent stability with time-on-stream at 500 and 650 °C. However, a reversible catalyst deactivation seems to be operable when the reaction occurs at 600 °C, resulting in a progressive decrease of propane conversion, which, however, can be completely restored by increasing the temperature to 650 °C in He flow, respectively. The long-term stability of Rh/TiO2 catalyst in the form of pellets showed that this catalyst is not only active and selective but also stable, and therefore, it is a promising catalyst for the reaction of LPG steam reforming.

What catalysis needs from the electron microscopist

1988 ◽  
Vol 46 ◽  
pp. 694-695
Author(s):  
Alexis T. Bell
Keyword(s):  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Catalyst Deactivation ◽  
Surface Composition ◽  
Internal Surface ◽  
Active Phase ◽  
Atomic Scale ◽  
Metal Catalyst ◽  
Internal Surface Area ◽  
Porous Support

Heterogeneous catalysts, used in industry for the production of fuels and chemicals, are microporous solids characterized by a high internal surface area. The catalyticly active sites may occur at the surface of the bulk solid or of small crystallites deposited on a porous support. An example of the former case would be a zeolite, and of the latter, a supported metal catalyst. Since the activity and selectivity of a catalyst are known to be a function of surface composition and structure, it is highly desirable to characterize catalyst surfaces with atomic scale resolution. Where the active phase is dispersed on a support, it is also important to know the dispersion of the deposited phase, as well as its structural and compositional uniformity, the latter characteristics being particularly important in the case of multicomponent catalysts. Knowledge of the pore size and shape is also important, since these can influence the transport of reactants and products through a catalyst and the dynamics of catalyst deactivation.

Analytical Electron Microscopy study of two vehicle-aged automotive exhaust catalysts having dissimilar activities

1989 ◽  
Vol 47 ◽  
pp. 272-273
Author(s):  
Sooho Kim ◽  
M. J. D’Aniello
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Noble Metal ◽  
Catalyst Deactivation ◽  
Analytical Electron Microscopy ◽  
Microscopy Study ◽  
Metal Particles ◽  
Automotive Exhaust ◽  
Exhaust Catalysts ◽  
Analytical Electron

Automotive catalysts generally lose-agtivity during vehicle operation due to several well-known deactivation mechanisms. To gain a more fundamental understanding of catalyst deactivation, the microscopic details of fresh and vehicle-aged commercial pelleted automotive exhaust catalysts containing Pt, Pd and Rh were studied by employing Analytical Electron Microscopy (AEM). Two different vehicle-aged samples containing similar poison levels but having different catalytic activities (denoted better and poorer) were selected for this study.The general microstructure of the supports and the noble metal particles of the two catalysts looks similar; the noble metal particles were generally found to be spherical and often faceted. However, the average noble metal particle size on the poorer catalyst (21 nm) was larger than that on the better catalyst (16 nm). These sizes represent a significant increase over that found on the fresh catalyst (8 nm). The activity of these catalysts decreases as the observed particle size increases.

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