• Transactions of the Korean hydrogen and new energy society
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• v.26 no.2
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• pp.96-104
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• 2015

Reactivity of commercial WGS catalyst and four new catalysts(RMC-3, PC-73, PC-67SU, PC-59) manufactured with various compositions by Korea Electric Power Research Institute(KEPCO RI) were compared to select suitable WGS catalyst for SEWGS system. Steam/CO ratio, gas velocity, flow rates of syngas, and temperature were considered as operating variables. As a result, commercial catalyst showed the highest CO conversion and RMC-3 catalyst showed also high CO conversion. Therefore, commercial and RMC-3 catalysts were selected as applicable catalysts. However, PC-73 catalyst showed low CO conversion at low temperature($200^{\circ}C$) but showed good reactivity at high temperature($225{\sim}250^{\circ}C$), and therefore, PC-73 catalyst was selected as applicable catalyst for high temperature operation. Continuous operations up to 24 hours for those three catalysts(commercial, RMC-3, PC-73) were conducted to check reactivity decay of catalysts. All three catalysts maintained their original reactivity.

• Korean Chemical Engineering Research
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• v.56 no.3
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• pp.297-302
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• 2018

Bead type and hollow fiber type catalyst (HFC, Hollow Fiber type Catalyst) was prepared by $La_{0.1}Sr_{0.9}Co_{0.2}Fe_{0.8}O_{3-{\delta}}$ (LSCF1928) perovskite powder catalyst which showed excellent methane complete oxidation characteristics through previous studies. The HFC have a cylindrical shape with an empty interior, and pores can be formed through Phase inversion method so the specific surface area can be remarkably improved. In the case of the bead type catalyst prepared by adding Methyl Cellulose (MC), $SrCO_3$ was produced in addition to the original catalyst composition of LSCF1928 due to the reaction of $CO_2$ emitted from MC and Sr of the catalyst. In the case of the HFC, a single phase perovskite structure was obtained without impurities. The HFC calcined at $700{\sim}900^{\circ}C$ showed pore structure of finger-sponge-finger structure, and 99.9% oxygen conversion rate was achieved through complete oxidation of methane at $475^{\circ}C$. Air gap and spinning pressure condition were changed to control the HFC pore. 2 cm air gap and 7 bar spinning pressure showed the best catalytic performance and achieved oxygen conversion rates of more than 70.65%, 93.01%, and 99.99% at $425^{\circ}C$, $450^{\circ}C$ and $475^{\circ}C$, respectively.

• Clean Technology
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• v.25 no.1
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• pp.1-6
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• 2019

Effects of the Cu and K addition and the reduction condition of Fe-based catalysts for Fischer-Tropsch reaction are studied in a continuous flow reactor in this research. The catalysts for the reaction were prepared by homogeneous precipitation followed by incipient wetness impregnation. Physicochemical properties of the $Al_2O_3$ supported Fe-based catalysts are characterized by various methods including X-ray diffraction (XRD), temperature programmed reduction (TPR), and scanning electron microscopy (SEM). Catalytic activities and stabilities of the Fe/Cu/K catalyst are investigated in time-on-stream for an extended reaction time over 216 h. It is found that a reduction of the catalysts using a mixture of CO and $H_2$ can promote their catalytic activities, attributed to the iron carbides formed on the catalysts surface by X-ray diffraction analysis. The addition of Cu induces a fast stabilization of the reaction reducing the time to reach at the steady state by enhancement of catalytic reduction. The addition of K to the catalysts increases the CO conversion, while the physical stability of catalyst decreases with potassium loading up to 5%. The Fe/Cu (5%)/K (1%) catalyst shows an enhanced long term stability for the Fischer-Tropsch reaction under the practical reaction condition, displaying about 15% decrease in the CO conversion after 120 h of the operation.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.4
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• pp.355-363
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• 2014

Thermal shock or overheating of WGS catalyst for SEWGS system during hydrogen pre-treatment can cause reactivity decay of the catalyst. To select appropriate pre-treatment condition, temperature profiles of catalyst bed (or outside fluidized particle bed of bed insert) during pre-treatment were measured and then CO conversions of those catalysts during WGS reaction were also measured and compared. Drastic overheating of catalyst took place when we reduce catalyst at fixed bed condition and these catalysts showed low CO conversion during WGS reaction. On the contrary, there was no overheating of catalyst at fluidized bed condition not only physical mixing case but also bed insert case. Spring type bed insert showed acceptable CO conversion even at low WGS content. Consequently, feasibility of high CO conversion without decay of reactivity of catalyst and holding the WGS catalyst inside the SEWGS reactor as tablet shape were confirmed using spring type bed insert.

• Clean Technology
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• v.24 no.1
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• pp.63-69
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• 2018

The reduction reaction characteristics and physicochemical properties were studied for the selection of oxygen carrier, which is the core of the chemical looping combustion (CLC) technology. Fuel conversion and $CO_2$ selectivity of oxygen carrier according to the concentration of reducing gas and the reduction temperature using three kinds of oxygen carrier (SDN70, N018-R2, N016-R4) were measured and compared. In addition, Attrition Index (AI) and BET surface area were measured to analyze the attrition resistance and the surface characteristics of the oxygen carrier. As a result, it was confirmed that all three kinds of oxygen carrier were suitable for use in chemical roofing combustion system, and the best particle was determined to be N016-R4.

• Applied Chemistry for Engineering
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• v.5 no.2
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• pp.327-336
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• 1994

The synergistic effects in mechanical mixture catalysts of Mo-V-O and metal oxide were investigated for the selective oxidation of acrolein. The metal oxides used are $SnO_2$, ${\alpha}-Sb_2O_4$, $WO_3$, ${\alpha}-Al_2O_3$, CuO, $MnO_2$, $Cu_2O$, MgO, CoO, and ZnO. Mechanical mixtures of Mo-V-O plus $SnO_2$ or ${\alpha}-Sb_2O_4$ had resulted in higher conversion of acrolein and higher yield of acrylic acid than Mo-V-O. The origin of the synergy is attributed to the cooperation of Mo-V-O and $SnO_2$ or ${\alpha}-Sb_2O_4$, in which $SnO_2$ or ${\alpha}-Sb_2O_4$ forms dissociated oxygens at their oxygen vacancies and transports them to Mo-V-O. $Cu_2O$, MgO, CuO, and $MnO_2$, increased conversion of acrolein but decreased yield of acrylic acid. CoO and ZnO inhibited the catalytic performance of Mo-V-O. The different role of these metal oxides is explained in terms of their oxidation-reduction properties.

• Journal of Energy Engineering
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• v.12 no.2
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• pp.145-153
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• 2003

In order to develop the carbonation process as a core technology of zero emission coal power plant, study on characterization of methane steam reforming (MSR) which is main reaction of this process was carried out. The effects of gas hourly space velocity (GHSV), steam/carbon (S/C) ratio and pressure in the MSR using reforming catalyst were investigated. The equilibrium composition of the gases produced in the MSR were obtained below GHSV 7,000 hr$\^$-1/. The operating conditions of carbonation process using hybrid reaction (MSR+CO$_2$ adsorption using CaO) were 700∼800$^{\circ}C$ and S/C ratio of 2.5∼3. The equilibrium mixture of gases composed of 75∼78% H$_2$ and 8∼9％ CO$_2$ at atmospheric pressure and 60∼78% H$_2$ and 9∼l1% CO$_2$ at 1∼30 atm respectively under above operating conditions.

• Korean Chemical Engineering Research
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• v.49 no.1
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• pp.21-27
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• 2011

The comparison work was conducted for the methanol steam reforming among commercial Cu-based catalysts, viz. ICI-M45, which is for the methanol synthesis, MDC-3 and MDC-7, which are for the water-gas shift reaction. The catalytic activity for the water-gas shift reaction was also compared over three catalysts. Among them, MDC-7 showed the highest methanol conversion and formation rate of hydrogen and carbon dioxide at 473 K for the methanol steam reforming. To find out any promotional effect between ICI-M45 and MDC-7, three different packing methods with these two catalysts were examined. However, no synergistic effect was observed. The catalytic activity for watergas shift reaction decreased in the following order: MDC-7 > MDC-3 > ICI-M45. The highest activity of MDC-7 for the methanol steam reforming as well as the water-gas shift reaction can be due to its high surface area, copper dispersion, and an adequate Cu/Zn ratio.

• 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.

• Applied Chemistry for Engineering
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• v.4 no.4
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• pp.701-708
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• 1993

Hydrodemetallation(HDM) of VO-tetraphenylporphyrin(VO-TPP) was studied over $CoMo/{\gamma}-Al_2O_3$ catalyst at emperatures between $300^{\circ}C$ and $400^{\circ}C$, the total pressure between $15{\times}10^5$ and $30{\times}10^5$ Pa and the contact times between 0.008 and 0.020gcat. hr./ml teed. HDM of VO-TPP was inhibited by pyridine because the increase of pyridine concentration(up to 4mole%) caused the decrease of HDM conversion. The reaction rate of VO-TPP was found to be apparently 1st order over $350^{\circ}C$ and its activation energy was determined to be about 23kca1/mo1e by Arrhenius plot. Pore mouth-plugging phenomena were shown by ad/desorption isotherm and pore size distribution of fresh and aged catalysts.