• Applied Chemistry for Engineering
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• v.9 no.1
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• pp.141-148
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• 1998

Reactivity of Pt catalysts(0.2, 0.5 wt% Pt) supported on solid super acid, $ZrO_2$ $SO_4{^{2-}}$ for low-temperature oxidation was investigated for complete oxidation of cyclohexane. Catalytic activity measured as reactant conversion in a packed-bed tubular reactor increased in accordance with the acidity and specific surface area of the catalyst activity and specific surface area of $Pt/ZrO_2$ $SO_4{^{2-}}$ catalyst were diminished by adding potassium during catalyst preparation. the catalyst activity decreased in accordance with the amount of potassium added. In addition, $Pt/ZrO_2$ $SO_4{^{2-}}$ catalyst exhibited an activity greater than that of a $Pt/SiO_2$ or $Pt/Al_2O_3$ catalyst possessing much larger specific surface area at $250^{\circ}C$ for the reactant stream of 15.000 ppm cyclohexane concentration and $18,000hr^{-1}$ space velocity, a cyclohexane conversion as high as 96% was obtained over 0.2 wt% $Pt/ZrO_2$ $SO_4{^{2-}}$, whereas cyclohexane conversions over 0.2 wt% $Pt/SiO_2$ and 0.2 wt% $Pt/Al_2O_3$ were 83 and 79%, respectively.

• Journal of Energy Engineering
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• v.19 no.4
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• pp.221-227
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• 2010

In this study, we consider gas generation characteristics on pyrolysis of eco-fuel which were made by mixing of Pitch Pine and Lauan sawdust as biomass and polyethylene, polypropylene, polystyrene as municipal plastic wastes with catalyst in fixed bed reactor. From the result of higher heating value(HHV) measurement and of ultimate analysis, the heating value of plastic wastes and a hydrogen content in plastic sample are higher than biomass. An activation energy was reduced by a catalyst addition. However the catalyst content influence over 5 wt% was insignificant. The yield of hydrogen from gasification of biomass containing plastic wastes such as polyethylene, polypropylene and polystyrene were obtained higher than that of sole biomass. The high temperature and mixture ratio of catalyst conditions induced to high hydrogen yield in most of the samples. As the influence of catalyst, the hydrogen yield by catalytic reaction was higher than non-catalytic reaction. We confirmed that Ni-$ZrO_2$ catalyst is more active in increasing the hydrogen yield in comparison with that of carbonate catalyst. The maximum hydrogen yield was 65.9 vol.%(Pitch Pine / polypropylene / 20 wt.% Ni-$ZrO_2$(1:9) at $900^{\circ}C$).

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.4
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• pp.391-397
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• 2011

The use of Hydrogen as a fuel is receiving considerable attention and as a result, research on novel methods of hydrogen production is necessary so that the hydrogen demands in the future can be satisfied. This study presents experimental data on methanol Autothermal Reformation that quantifies the relationship between the oxygen-to-methanol ratio ($O_2/CH_3OH$) and reformer efficiency. For each catalyst configuration, the $O_2/CH_3OH$ was varied from 0.1 to 0.4, with an increment of 0.05, to investigate the effects of $O_2/CH_3OH$ on the reactor performance, including temperature profile, conversion, and efficiency. $O_2/CH_3OH$ was increased from 0.15 to 0.20, and the catalyst bed temperature increased by $235^{\circ}C$ to approximately $550^{\circ}C$. The catalyst bed temperature increased with increasing $O_2/CH_3OH$ as the reaction shifted from endothermic to exothermic reaction and as a result, excess heat, which raised the reactor temperature, was generated. The reactor performance was shown to be highly dependent on $O_2/CH_3OH$. The optimum $O_2/CH_3OH$ = 0.30 found in the experimental tests is 30% higher than the theoretical optimum of 0.23. This is attributed to a combination of factors such as the concentrations of the $O_2$ and $CH_3OH$ gas, reaction rate, catalyst effects, heat loss from the reactor, and the difference between the actual amounts of reaction products formed and the theoretical amounts of the reaction products.

• Clean Technology
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• v.26 no.2
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• pp.145-150
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• 2020

Nitrous oxide (N₂O) is one of the six greenhouse gases, and it is essential to reduce N₂O by showing a global warming potential (GWP) equivalent to 310 times that of carbon dioxide (CO₂). Selective catalytic reduction (SCR) is a technology that converts ammonia into harmless N₂ and H₂O by using ammonia as a reducing agent to remove NOx, one of the air pollutants; the process also produces high denitrification efficiency. In this study, the Fe-BEA catalyst was steam-treated at 100 ℃ for 2 h before Fe ion exchange in the fixed bed reactor in order to investigate the effect of the steam-treated Fe-BEA catalyst on the NH₃-SCR reaction. NH₃-SCR reaction test of synthesized catalysts was performed at WHSV = 180 h^-1, 370 to 400 ℃ in the fixed bed reactor. The Fe-BEA(100) catalyst steam-treated at 100 ℃ showed a somewhat higher activity than the Fe-BEA catalyst at 370 to 390 ℃. The catalysts were characterized by BET, ICP, NH₃-TPD, H₂-TPR, and ²⁷Al MAS NMR in order to determine the cause affecting NH₃-SCR activity. The H₂-TPR result confirmed that the Fe-BEA(100) catalyst had a higher reduction of isolated Fe³⁺ than the Fe-BEA catalyst, and that the steam treatment increased the amount of isolated Fe³⁺ as an active species, thus increasing the activity.

• Transactions of the Korean hydrogen and new energy society
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• v.18 no.4
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• pp.382-390
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• 2007

To check the feasibility of SMART(Steam Methane Advanced Reforming Technology) system, an experimental investigation was performed. A fluidized bed reactor of diameter 0.052m was operated cyclically up to 10th cycle, alternating between reforming and regeneration conditions. FCR-4 catalyst was used as the reforming catalyst and calcined limestone(domestic, from Danyang) was used as the $CO_2$ absorbent. Hydrogen concentration of 98.2% on a dry basis was reached at $650^{\circ}C$ for the first cycle. This value is much higher than $H_2$ concentration of 73.6% in the reformer of conventional SMR (steam methane reforming) condition. The hydrogen concentration decreased because the $CO_2$ capture capacity decreased as the number of cycles increased. However, the average hydrogen concentration at 10th cycle was 82.5% and this value is also higher than that of SMR. Based on these results, we could conclude that the SMART system can replace SMR system to generate pure hydrogen without HTS (high tempeature shift), LTS (low temperature shift) and $CO_2$ separation process.

• Journal of Environmental Science International
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• v.22 no.8
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• pp.945-951
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• 2013

Alumina-supported catalysts containing different transition metals such as Cu, Cr, Mn, Zn, Co, W were investigated for their activity in the selective oxidation of toluene. Catalytic oxidation of toluene was investigated at atmospheric pressure in a fixed bed flow reactor system over transition metals with $Al_2O_3$ catalyst. The result showed the order of catalytic activities for the complete oxidation of toluene was Mn > Cu> Cr> Co> W> Zn for 5wt.% transition $metals/Al_2O_3$. $Mn/Al_2O_3$ catalysts containing different amount of Mn were characterized by X-ray diffraction spectroscopy for decision of loading amount of metal to alumina. 5 wt.%$Mn/Al_2O_3$ catalyst exhibits the highest catalytic activity, over which the toluene conversion was up to 90% at a temperature of $289^{\circ}C$.

• Journal of Environmental Science International
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• v.18 no.4
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• pp.445-450
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• 2009

In this study, the fundamental experiments were performed for catalytic oxidation of NO (50 ppm) on $MnO_2$ in the presence of ozone. The experiments were carried out at various catalytic temperatures ($30-120^{\circ}C$) and ozone concentrations (50-150 ppm) to investigate the behavior of NO oxidation. The honeycomb type $MnO_2$ catalyst was rectangular with a cell density of 300 cells per square inch. Due to $O_3$ injection, NO reacted with $O_3$ to form $NO_2$, which was adsorbed at the $MnO_2$ surface. The excessive ozone was decomposed to $O^*$ onto the $MnO_2$ catalyst bed, and then that $O^*$ was reacted with $NO_2$ to form $NO_3^-$. It was found that the optimal $O_3$/NO ratio for catalytic oxidation of NO on $MnO_2$ was 2.0, and the NO removal efficiency on $MnO_2$ was 83% at $30^{\circ}C$. As a result, NO was converted mainly to $NO_3^-$.

• Journal of Korean Society for Atmospheric Environment
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• v.13 no.4
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• pp.319-325
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• 1997

The catalytic decomposition of CFC-113(1,1,2-trichloro-1,2,2-trifluoroethane) was studied over an activated carbon catalyst in a fixed-bed reactor at the temperature from 300 to 600$^\circ$C, the space velocity (SV) of 1800 $\sim 14400h^{-1}$ and the mole ratio(decomposition agent/CFC-113) of 0.25 $\sim$ 5. In the absence of a decomposition agent, the decomposition efficiency of CFC-113 was low but when a decomposition agent was added to the gas stream, it was dramatically increased with the increase of temperature. In particular, in the presence of n-hexane as the decomposition agent it showed a high decomposition efficiency compared with benzene at 400$^\circ$C. It was found that the decomposition activity of CFC-113 was very sensitive to reaction temperature. Thus it is expected that to raise the reaction temperature is more effective than to increase the residence time and the amount of decomposition agent. Over the activated carbon catalyst more than 99% decomposition was achieved at the reaction temperature of 600$^\circ$C, SV of 7200$h^{-1}$, the mole ration $(C_6H_{14}/CFC-113)$ of 1 in this study.

• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.343-347
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• 2012

The decomposition behaviors of gaseous cyanides in non-thermal plasma-catalyst hybrid reactor have been investigated with the variation of discharge power, influent concentration of cyanide, humidity of air carrier and packed materials in the reactor. Destruction of cyanides by plasma only process was very difficult compared to that of trichloroethylene. But the destruction efficiencies of cyanides were dramatically improved through packing alumina or Pt/alumina bead in the plasma discharge region. From the results, it could be assumed that thermal catalytic effect is involved simultaneously with plasma in the reaction of cyanides destruction on the alumina or Pt/alumina packed plasma reactor.

• Journal of the Korean Chemical Society
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• v.57 no.6
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• pp.769-777
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• 2013

The effect of operating conditions (temperature and the partial pressures of H2 and CO) on the reaction rate of Fischer-Tropsch synthesis (FTS) were investigated by carrying out experiments according to a Box-Behnken design (BBD), and were mathematically modeled by using response surface methodology (RSM). The catalyst used was a nano-structured cobalt/manganese oxide catalyst, which was prepared by thermal decomposition. The rate of synthesis was measured in a fixed-bed micro reactor with $H_2/CO$ molar feed ratio of 0.32-3.11 and reactor pressure in the range of 3-9.33 bar at space velocity of $3600h^{-1}$ and a temperature range of 463.15-503.15 K, under differential conditions (CO conversion below 2%). The results indicated that in the present experimental setup, the temperature and the partial pressure of CO were the most significant variables affecting reaction rate. Based on statistical analysis the quadratic model of reaction rate of FTS was highly significant as p-value 0.0002.