• Journal of Korean Society of Environmental Engineers
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• v.28 no.3
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• pp.323-328
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• 2006

The purpose of this paper was to investigate the reforming characteristics and optimum operating condition of the GlidArc-assisted $C_3H_8$ reforming reaction for the synthesis gas(SynGas) production without formation of carbon black from propane using GildArc plasma reforming. Also, in order to increase the hydrogen production and the propane conversion rate, 13 wt % nickel catalyst was filled into the catalytic reactor and parametric screening studies were conducted, in which there were the variations of vapor mole ratio$(H_2O/C_3H_8),\;CO_2$ mole ratio($CO_2/C_3H_8$), input power and injection flow rate. When the variations of vapor mole ratio, $CO_2$ mole ratio, input power and injection flow rate were 1.86, 0.48, 1.37 kW and 14 L/min, respectively, the conversion rate of the propane reached its most optimal condition, or 62.6%. Under the condition mentioned above, the dry basic concentrations of the SynGas were $H_2\;44.4%,\;CO\;18.2%,\;CH_4\;11.2%,\;C_2H_2\;2.0%,\;C_3H_6\;1.6%,\;C_2H_4\;0.6%\;and\;C_3H_4$ 0.4%. The conversion rate of carbon dioxide was 29.2% and the concentration ratio of hydrogen to carbon monoxide($H_2/CO$) in the SynGas was 2.4.

• Korean Chemical Engineering Research
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• v.51 no.3
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• pp.319-324
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• 2013

The partial oxidation reaction of methane was investigated to produce syngas with $Ni/CeO_2-ZrO_2$, $Ni-Ru/CeO_2-ZrO_2$ and $Ni-Pd/CeO_2-ZrO_2$ catalysts. Honeycomb metallic monolith was applied in order to obtain high catalytic activity and stability in partial oxidation reforming. The catalysts were characterized by XRD and FE-SEM. The influence of various catalysts on syngas production was studied for the feed ratio (O/C), GHSV and temperature. Among the catalysts used in the experiment, the $Ni-Pd/CeO_2-ZrO_2$ catalyst showed the highest activity. The 99% of $CH_4$ conversion was obtained at the condition of T=$900^{\circ}C$, GHSV=10,000 $h^{-1}$ and feed ratio O/C=0.55. It was confirmed that $H_2$ yield increased slightly as O/C ratio increased, while CO yield remained almost constant. Also, $CH_4$ conversion decreased as GHSV increased. It was found that the safe range of GHSV for high $CH_4$ conversion was estimated to be less than 10,000 $h^{-1}$.

• Korean Chemical Engineering Research
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• v.49 no.2
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• pp.168-174
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• 2011

Various La-based perovskite catalysts were prepared by a Pechini method, and they were applied to the low-temperature oxidation of odor compounds exhausted from waste food treatment process for effective deodorization. Quantitative and qualitative analyses of exhausted gas were conducted to measure the amount of major odor compounds with respect to operation time. A standard odor sample composed of major odor compounds was then prepared for use as a feed for oxidation reaction system. Various transition metal(M)-substituted La-based perovskite catalysts ($LaMO_{3}$: M=Cr, Mn, Fe, Co, and Ni) were prepared and applied to the oxidation of odor compounds in order to investigate the $LaNiO_3$ catalyst showed the best catalytic performance. Pt-substituted perovskite catalysts ($LaNi_{1-x}Pt_{x}O_{3}$: x=0, 0.03, 0.1, and 0.3) were then prepared for enhancing the catalytic performance. It was found that $LaNi_{0.9}Pt_{0.1}O_{3}$ catalyst served as the most efficient catalyst. Supported perovskite catalysts ($XLaNi_{0.9}Pt_{0.1}O_{3}/Al_{2}O_{3}$: X=perovskite content(wt%), 0, 10, 20, 30, 40, 50, and 100) were finally applied for the purpose of maximizing the catalytic performance of perovskite catalyst in the low-temperature oxidation reaction. Catalytic performance of $XLaNi_{0.9}Pt_{0.1}O_{3}/Al_{2}O_{3}$ catalysts showed a volcano-shaped curve with respect to perovskite content. Among the catalysts tested, $20LaNi_{0.9}Pt_{0.1}O_{3}$/$Al_{2}O_{3}$ catalyst exhibited the highest conversion of odor compounds of 88.7% at $180^{\circ}C$.

• Korean Chemical Engineering Research
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• v.51 no.4
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• pp.418-425
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• 2013

The catalytic conversion of ethanol to aromatic compounds ETA was studied over ZSM-5 heterogeneous catalysts. The effect of reaction temperature, weight hourly space velocity (WHSV), and addition of water and methanol, which are the potential impurities of bio-ethanol, on the catalytic performance was investigated in a fixed bed reactor. Commercial ZSM-5 catalysts having different Si/$Al_2$ ratios of 23 to 280 and modified ZSM-5 catalysts by addition of metal (Zn, La, Cu, and Ga) were used for the activity and stability tests in ETA reaction. The catalysts were characterized with ammonia temperature programmed desorption ($NH_3$-TPD) and nitrogen adsorption-desorption techniques. The results of catalytic performance revealed that the optimal Si/$Al_2$ ratio of ZSM-5 is about 50~80 and the selectivity to aromatic compounds decreases in the order of Zn/La > Zn > La > Cu > Ga for the modified ZSM-5 catalysts. Among these catalysts from the ETA reaction, Zn-La/ZSM-5 showed the best catalytic performance for the ETA reaction. The selectivity to aromatic compounds was 72% initially and 56% after 30 h over the catalysts at reaction temperature of $437^{\circ}C$ and WHSV of $0.8h^{-1}$.

• Korean Chemical Engineering Research
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• v.50 no.4
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• pp.723-728
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• 2012

The production of biodiesel by transesterification of soybean oil was performed on $MoO_3$, $SnO_2$ and $CeO_2$ mixed oxides. The catalysts were characterized using XRD and $NH_3$-TPD. $MoO_3$ showed the highest activity among the three metal oxides. When 7 wt% of catalysts was introduced into the reactants, the highest activity was obtained and the water added to reactant decreased the catalytic activity. $MoO_3$ and $SnO_2$ mixed with 50:50 showed the highest activity and $CeO_2$ added with 20% on the $MoO_3-SnO_2$ mixed oxide also showed the highest activity. The catalytic activity showed to have a good relationship with the amount of acid site of catalysts. When the waste soybean oil was used as a reactant, the conversion was decreased about 30%.

• Korean Chemical Engineering Research
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• v.51 no.2
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• pp.189-194
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• 2013

A sulfonated activated carbon (AC-$SO_3H$) was used as a solid acid catalyst for dehydration of sorbitol to isosorbide and its catalytic performance was compared with the commercial solid acid such as acidic ion exchange resin, Amberlyst-36, and sulfated copper oxide. The catalytic performance with 100% sorbitol conversion and 52% isosorbide selectivity was obtained over AC-$SO_3H$ at 423.15 K. Although AC-$SO_3H$ possessed only 0.5 mmol/g of sulfur content, it showed the similar dehydration activity of sorbitol to isosorbide with Amberlyst-36 (5.4 mmol/g) at 423.15 K. Based on the high thermal and chemical stability of AC-$SO_3H$, one-step reactive distillation, where isosorbide separation can be carried out simultaneously with sorbitol dehydration, was tried to increase the recovery yield of isosobide from sorbitol. The reactive distillation process using AC-$SO_3H$, the turnover number of AC-$SO_3H$ was 4 times higher than the conventional two-step process using sulfuric acid.

• Applied Chemistry for Engineering
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• v.9 no.3
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• pp.355-360
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• 1998

Reduction activity of precious metal-loaded HZSM-5 for NO has been studied and was compared to that of Cu-HZSM-5 in the presence of excess oxygen. It was found that among the catalysts used in this study, Ru-HZSM-5 was the most active catalyst for the reduction of NO to $N_2$ in the absence of hydrocarbon reductant. The highest conversion obtained was 45%. No severe inhibition of water vapor to the reduction was observed. It is suggested that the higher catalytic activity of Ru-HZSM-5 may result from the better ability to oxidize NO to $NO_2$ in the presence of excess oxygen. A proposed reaction mechanism for the reduction of NO to $N_2$ in the presence of excess oxygen is that NO is oxidized to $NO_2$ on the surface of Ru-HZSM-5 catalyst and the adsorbed $NO_2$ on the surface is then decomposed to $N_2$. $NO_2$ is supposed to the reaction.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.1
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• pp.1-9
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• 2015

To satisfy stricter $NO_X$ emission regulations for light- and heavy-duty diesel vehicles, a control algorithm needs to be developed based on a selective catalytic reaction (SCR) dynamics model for chemical reactions. This paper presents the development and validation of a SCR dynamics model through test rig experiments and MATLAB simulations. A nonlinear state space model is proposed based on the mass conservation law of chemical reactions in the SCR dynamics model. Experiments were performed on a test rig to evaluate the effects of the $NO_X$ and $NH_3$ concentrations, gas temperature, and space velocity on the $NO_X$ conversion efficiency for the urea-SCR system. The parameter values of the proposed SCR model were identified using the experimental datasets. Finally, a control-oriented model for an SCR system was developed and validated from the experimental data in a MATLAB simulation. The results of this study should contribute toward developing a closed-loop control strategy for $NO_X$ and $NH_3$ slip reduction in the urea-SCR system for an actual engine test bench.

• Clean Technology
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• v.17 no.1
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• pp.41-47
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• 2011

[ $MnO_2$ ]catalysts were prepared by precipitation method using potassium manganate and manganese acetate. The effect of calcination temperatures of $MnO_2$ catalysts for CO oxidation has been studied and their physicochemical properties were studied by X-ray diffraction (XRD), $N_2$ sorption, temperature programmed reduction of $H_2$ ($H_2-TPR$), and temperature programmed desorption of CO (CO-TPD) techniques. $MnO_2$ calcined at $300^{\circ}C$ catalyst has a large surface area $181m^2/g$ having a narrow pore size distribution at 9 nm. The results of XRD and $H_2-TPR$ showed that the catalysts calcined at different temperatures showed mixed oxidation states of Mn such as $Mn^{4+}$ and $Mn^{3+}$. CO-TPD showed that the quantity of $CO_2$ desorbed was decreased with increasing the calcination temperatures. The catalytic activity over the catalyst calcined at $300^{\circ}C$ exhibited the highest conversion reaching to 100% at $200^{\circ}C$. $H_2O$ vapor showed an inhibiting effect on the efficiency of the catalyst because of co-adsorption with CO on the active sites of manganese oxide catalysts and the initial catalytic activity of CO oxidation could be regenerated by removing $H_2O$ vapor in the reactants.

• Clean Technology
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• v.17 no.1
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• pp.56-61
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• 2011

In this study, hydrocarcking of vacuum residue was carried out in an autoclave reactor at $450^{\circ}C$ and $500^{\circ}C$ with a commercial catalyst (HDM) and the quantitative product distributions were analyzed by GC-SIMDIS method or simple distillation. During catalytic hydrocracking, thermal cracking also occurred together with catalytic cracking and the higher conversion and selectivity of gasoline and naphtha were obtained at high reaction temperature. GC-SIMDIS and simple distillation revealed different results for the analysis of products produced at different hydrocracking temperatures; almost same results were obtained for the product produced at $500^{\circ}C$ but different ones for the product produced at $450^{\circ}C$. In the analysis of product produced at $450^{\circ}C$, the GC-SIMDIS showed that a main product was VGO while a main product in the simple distillation was diesel, which implies that the simple distillation for the $450^{\circ}C$ reaction was not accurate due to thermal cracking of the product by the simple distillation.