• Bulletin of the Korean Chemical Society
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• v.23 no.5
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• pp.674-678
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• 2002

The dehydrogenation of propane to propylene has been studied in an isothermal high-temperature shell-and-tube membrane reactor containing a Pd-coated ${\psi}$-Al2O3 membrane and a Pt/K/Sn/Al2O3 packed catalyst . A tubular Pd-coated ${\psi}$-Al2O3 membrane was prepared by an electroless plating method. This membrane showed high hydrogen to nitrogen permselectivities (PH2N2 = 10-50) at 400 $^{\circ}C$ and 500 $^{\circ}C$ with various transmembrane pressure drops. The employment of a membrane reactor in the dehydrogenation reaction, which selectively separates hydrogen from the reaction mixture along the reaction path, can greatly increase the conversion and enable operation of the reactor at lower temperatures. High hydrogen permselectivity has been confirmed as a key factor in determining the reactor performance of conversion enhancement.

• Clean Technology
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• v.14 no.2
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• pp.71-86
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• 2008

In this review we discussed the effective ways to catalytically derive value-added chemicals from propane which has been utilized only as an energy source so far. Among various propane-derived products, the most valuable chemicals such as propylene and acrylonitrile were mainly focused herein. Propylene could be manufactured through oxidative dehydrogenation of propane using $O_2,\;CO_2$, etc. as an oxidant for the purpose of overcoming thermodynamic limitations of propane dehydrogenation. On the other hand, propane ammoxidation would be an alternative to propylene ammoxidation for producing acrylonitrile since propane is much cheaper than propylene as a starting material. Although effective $MoVTeNbO_x$ catalysts have been developed fur propane ammoxidation in recent years, more detailed studies should be thoroughly performed. In carrying out both oxidative dehydrogenation and ammoxidation of propane fur a long period, the most critical issue is definitely considered to find out the most active and selective catalysts, which makes it possible to commercialize both reactions into economically viable processes.

• Clean Technology
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• v.22 no.2
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• pp.82-88
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• 2016

The loss of activity by coke is an important cause of catalyst deactivation during industrial operation. In this study, hydrogen ratio of reaction condition, which has influenced on coke formation over Pt-Sn catalyst, and regeneration of catalysts activity by coke burning, Pt sintering of coke burning as coke contents, effects of coke formation and deactivation with different Sn contents were confirmed. Pt-Sn-K catalyst supported on θ-alumina and γ-alumina was prepared progressively. Activity of regenerated catalyst for propane dehydrogenation was compared with fresh catalyst by coke burning, after propane dehydrogenation was carried out with different hydrogen ratio at 620 ℃ on fresh catalyst. Regenerated catalyst’s physical characterization such as BET, coke analysis and XRD was investigated. Through catalytic activity test and characterization, Sn contents of catalyst and hydrogen ratio in feed stream could affect coke formation on catalyst surface. Excessive coke makes loss of activity and Pt sintering during air regeneration process.

• Korean Chemical Engineering Research
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• v.57 no.4
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• pp.575-583
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• 2019

The results of the catalytic reaction by pulsed injection of reactants are useful for studying the initial reaction characteristics in the case of many coke invloved reactions. The dehydrogenation characteristics of alumina supported platinum tin catalysts were investigated by pulsed injection of propane. The yield of propylene was maximized when the reduction time of propane injection catalyst was $550^{\circ}C$. Raman analysis showed that the amount of coke was very small when PtSn (4.5) catalyst was used and the short contact time was simulated by propane pulse injection. n order to differentiate the degree of dispersion of platinum, PtSn (4.5) catalyst was sintered at $900^{\circ}C$ with hydrogen, and then the temperature of air - redispersion was varied and propane pulse was injected. As a result, conversione and yield were the highest when air-redispersion temperature is $600^{\circ}C$. The lower the air-redispersion temperature, the higher the selectivity. As the tin content in the platinum catalyst increased, the propane conversion was lowered, but the selectivity to propylene increased and the yield increased. From this, it can be seen that the tin-added platinum catalyst is less active than the platinum catalyst from the beginning of the reaction, which is less affected by coke. The dehydrogenation reaction by the propane pulse injection shows a higher conversion rate than the result of continuous injection due to the formation of COx, and the amount of coke is very small. Decrease in selectivity due to the formation of COx can be reduced by increasing the reduction temperature and time.

• Journal of the Korean Applied Science and Technology
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• v.33 no.2
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• pp.401-410
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• 2016

The $Pt-Sn/Al_2O_3$ catalysts mixed with metal oxides for propane dehydrogenation were studied. $Cu-Mn/{\gamma}-Al_2O_3$, $Ni-Mn/{\gamma}-Al_2O_3$, $Cu/{\alpha}-Al_2O_3$ was prepared and mixed with $Pt-Sn/Al_2O_3$ to measure the activity for propane dehydrogenation. As standard sample, $Pt-Sn/Al_2O_3$ catalyst mixed with glassbead was adopted. In the case of catalytic activity test after non-reductive pretreatment of catalyst and metal oxide, $Pt-Sn/Al_2O_3$ mixed with $Cu-Mn/{\gamma}-Al_2O_3$ showed higher conversion of 15% and similar selectivity at $576.5^{\circ}C$, compared to conversion of 8% in standard sample. In the case of catalytic activity test after reductive pretreatment of catalyst and metal oxde, $Cu/{\alpha}-Al_2O_3$ showed higer yield than standard sample. But, increase of yield of most of samples after reductive pretreatment was not significant, so it was found that lattice oxygen of $Cu-Mn/{\gamma}-Al_2O_3$ is effective to propane dehydrogenation.

• Journal of the Korean Applied Science and Technology
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• v.35 no.3
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• pp.757-767
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• 2018

In the propane dehydrogenation reaction proceeding at high temperature, the main cause of deactivation of the catalyst is coke deposition and sintering. In order to investigate the catalysts for reducing such inactivation, we have investigated the applicability of $MgAl_2O_4$ as a carrier for the catalytic dehydrogenation reaction. $MgAl_2O_4$ was prepared by Alcohthermal method at calcination temperature of 800, 900, $1000^{\circ}C$, and $Pt-Sn/MgAl_2O_4$ catalyst was prepared by supporting Pt and Sn by co-impregnation method. The reaction temperature was conducted at a high temperature of 650, $600^{\circ}C$ to confirm the thermal stability. As a result of the reaction experiment, it was confirmed that the conversion rate and yield of propane dehydrogenation reaction test were higher than that of the carrier-applied catalyst having a carrier calcination temperature of 900 and $1000^{\circ}C$, when the carrier-applied catalyst having a calcination temperature of $800^{\circ}C$ was used, It was found that the yield was higher than that of $Pt-Sn/{\theta}-Al_2O_3$ at $650^{\circ}C$. TGA, BET, XRD, CO-chemisorption, and SEM-EDS analyzes were performed for characterization. $MgAl_2O_4-800^{\circ}C$ was correlated with the relationship between good yield, Pt dispersion and low deactivation rate.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.218-221
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• 2009

Solid oxide fuel cells (SOFCs), as high-temperature fuel cells, have various advantages. In some merits of SOFCs, high temperature operation can lead to the capability for internal reforming, providing fuel flexibility. SOFCs can directly use CH4 and CO as fuels with sufficient steam feeds. However, hydrocarbons heavier than CH4, such as ethylene, ethane, and propane, induce carbon deposition on the Ni-based anodes of SOFCs. In the case of the ethylene steam reforming reaction on a Ni-based catalyst, the rate of carbon deposition is faster than among other hydrocarbons, even aromatics. In the reformates of heavy hydrocarbons (diesel, gasoline, kerosene and JP-8), the concentration of ethylene is usually higher than other low hydrocarbons such as methane, propane and butane. It is importatnt that ethylene in the reformate is removed for stlable operation of SOFCs. A new methodology, termed post-reforming was introduced for removing low hydrocarbons from the reformate gas stream. In this work, activity tests of some post-reforming catalysts, such as CGO-Ru, CGO-Ni, and CGO-Pt, are investigated. CGO-Pt catalyst is not good for removing ethylene due to low conversion of ethylene and low selectivity of ethylene dehydrogenation. The other hand, CGO-Ru and CGO-Ni catalysts show good ethylene conversion, and CGO-Ni catalyst shows the best reaction selectivity of ethylene dehydrogenation.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.07a
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• pp.33-36
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• 2003

This research was aimed at developing new catalytic membrane reactors to be used for : i) partial oxidation of toluene (to benzaldehyde and benzoic acid) ii) oxidative dehydrogenation of propane iii) complete oxidation of propane and toluene. The reactor is particularly useful for the optimisation and the industrial development of heterogeneous catalytic processes, particularly for those processes where it is necessary to control the reactants stoichiometry in the reaction zone. This control limits consecutive reactions, thus obtaining high selectivity with industrially interesting conversions. This presentation will concentrate on the partial oxidation of toluene.

• Korean Chemical Engineering Research
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• v.60 no.3
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• pp.459-467
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• 2022

Redispersion of Pt-Sn particles in Pt, PtSn catalyst which have been sintered by high temperature hydrogen reduction was investigated using oxygen treatment with various temperatures. The aim of this study was to understand the relationship between the catalytic activity for propane dehydrogenation reaction and the change in the physicochemical properties of the catalyst. X-ray diffraction analysis (XRD), CO pulse chemisorption, and H₂ temperature programmed reduction (H₂-TPR) were performed to investigate the state of active metal and interactions between particles of redispersed catalyst. It was confirmed that the dispersion and particle size of platinum, the crystal phase of the catalyst, and the reduction behavior were changed according to the oxygen treatment. As for the catalytic activity in propane dehydrogeantion, sintered PtSn catalyst treated with oxygen at 500 ℃ showed best activity and recovery of initial activity. It was confirm that catalyst after oxygen treatment at 500 ℃ showed high dispersion of Pt and decreased particle size as the results of CO pulse chemisorption and XRD of catalyst, and thus the redispersion of PtSn particles in sintered catalyst was occurred. Catalytic activity was recovered due to redispersion using oxygen treatment, and the activity recovery of the PtSn catalyst was higher than that of Pt catalyst.

• Applied Chemistry for Engineering
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• v.9 no.1
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• pp.129-134
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• 1998

Conversion of propane to acrylonitrile via ammoxidation was studied using physically mixed catalysts composed of $Nb_2O_5(10{\sim}30wt%)$ and $V_{0.4}Mo_1Te_{0.1}$. Catalytic activities of ammoxidation were improved by adding strong acidic niobium oxide to $V_{0.4}Mo_1Te_{0.1}$, the selectivities to acrylonitrile+propylene being remained constant. The maximum activity was obtained at the mixing ratio 25wt% niobium oxide in $Nb_2O_5-V_{0.4}Mo_1Te_{0.1}$. Niobium oxide was found to be a selective catalyst for the oxidative dehydrogenation of propane.