• Clean Technology
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• v.6 no.1
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• pp.17-25
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• 2000

Catalytic oxidation of volatile organic compounds(benzene, toluene, xylene) over transition metals/ALO-6 catalysts was investigated in a fixed bed flow reactor system at atmospheric pressure. The orders of catalytic activities for the complete oxidation of toluene were Cu>Mn>Fe>V>Mo>Co>Ni>Zn for 15% transition metals/ALO-6 catalyst system. Increasing the calcination temperature resulted in decreasing the specific surface areas of catalyst, subsequently the catalytic activity. The loading of Cu on ALO-6 had a great effect on the catalytic activity and 5% Cu/ALO-6 catalyst showed higher catalytic activity, which may be contributed to the uniformly distributed active sites. Benzene, toluene and xylene were completely oxidized to carbon dioxide over 5% Cu/ALO-6 catalyst at over $380^{\circ}C$ and 4.5 g-cat.hr./g-mole. The orders of the kinds of reactants for catalytic activity over 5% Cu/ALO-6 were toluene>xylene>benzene. As the concentration of reactant increased, the catalytic activity decreased due to self-poison of reactant.

• Clean Technology
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• v.12 no.2
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• pp.87-94
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• 2006

The reduction of $SO_2$ to elemental sulfur by CO over a series of iron niobate with nominal Nb/Fe atomic ratios of 1/0, 10/1, 5/1, 1/1, 1/5, 1/10 and 0/1 was studied with a flow fixed-bed reactor. Strong synergistic phenomena in catalytic activity and selectivity were observed for the iron niobate catalysts, and the best catalytic performance was observed for the catalyst with Fe/Nb atomic ratio of 1/1. The active phase of the activated iron niobate catalysts was identified to be $FeS_2$ using XRD and XPS. Selective reduction of $SO_2$ by CO was followed by the COS intermediate mechanism.

• Applied Chemistry for Engineering
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• v.27 no.4
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• pp.407-414
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• 2016

Ex-situ catalytic pyrolysis of a Korean native oak tree over microporous zeolites (HZSM-5, HBeta, and HY) was performed by using a fixed bed reactor. The effect of sample to catalyst ratio and reaction temperature was also investigated to optimize production conditions of high quality bio-oil. Among three catalysts, HZSM-5 showed the highest aromatic formation due to its proper pore size and strong acidity. Although HY and HBeta also showed the catalytic activity, they produced larger amounts of coke due to their larger pore size. The smaller ratio of the sample to the catalyst and higher reaction temperature were also required to maximize the yields of aromatic hydrocarbons via the catalytic pyrolysis of oak tree over HZSM-5.

• Journal of Energy Engineering
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• v.8 no.2
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• pp.248-255
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• 1999

Catalytic cracking of pyrolysed waste lubricating oil over solid acid catalysts (HY zeolite, ${\beta}$-zeolite, HZSM-5) has been carried out in a micro-fixed bed system. The feed oil for catalytic activity tests has been prepared by thermal cracking of waste lubricating oil under the reaction conditions of 480$^{\circ}C$, 60 min. Optimum reaction conditions for the maximum light oil yields($\_$21/) were WHSV(weight hourly space velocity)=1 at 375$^{\circ}C$. The amounts of total and strong acid sites appeared to be the largest in ${\beta}$-zeolite as determined by NH$_3$, TPD. It is seen that the catalytic activity order, in terms of the light fuel oil ($\_$21/) production, were HY zeolite)${\beta}$-zeolite>HZSM-5. Also, coke formation followed the same order. The highest activity in HY zeolite may be attributed from the fact that it has supercages facilitating the easy diffusion of larger molecules and also the effectiveness of the acid sites for cracking within the pore. This fact could be confirmed by the coke formation characteristics.

• Korean Chemical Engineering Research
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• v.53 no.1
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• pp.116-120
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• 2015

Synthesis of butenes through dehydration of 2-butanol was investigated over HY zeolite catalysts. 2-Butanol dehydration reaction was carried out in a fixed bed catalytic reactor. 2-Butanol conversion was increased with increase of $Si/Al_2$ ratio of HY zeolite catalysts, which can be ascribed to increase of acid strength with increase of $Si/Al_2$ ratio. Selectivities to 1-butene, trans-2-butene, and cis-2-butene were not greatly influenced by the change of the $Si/Al_2$ ratio of HY zeolite. As a result, it was advantageous to use a HY zeolite catalyst with 60 $Si/Al_2$ ratio for maximizing the yield of 1-butene in the dehydration of 2-butanol. The optimal reaction temperature for maximizing the yield of 1-butene was $250^{\circ}C$ over HY (60) catalyst.

• Clean Technology
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• v.20 no.3
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• pp.256-262
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• 2014

Catalytic oxidation characteristics of benzene as a VOC was investigated in a fixed bed flow reactor using $Cu/{\gamma}-Al_2O_3$ catalyst. The parametric tests were conducted at the reaction temperature range of $200{\sim}500^{\circ}C$, benzene concentration of 400~650 ppm, gas flow rate of 50~100 cc/min, and space velocity range of $7,500{\sim}22,500hr^{-1}$. The property analyses by using the BET, SEM, TGA and the conversion of catalytic oxidation of benzene were examined. The experimental results showed that the conversion was increased with decreasing benzene concentration, gas flow rate and space velocity. Benzene oxidation reaction over $Cu/{\gamma}-Al_2O_3$ catalyst could be expressed as the first order homogeneous reaction of which the activation energy was 17.2 kcal/mol and frequency factor was $1.33{\times}10^6sec^{-1}$.

• Applied Chemistry for Engineering
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• v.29 no.2
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• pp.248-251
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• 2018

Catalytic pyrolysis of the waste paper cup containing coffee residual (WPCCCR) was performed using a fixed bed reactor and pyrolyzer-gas chromatography/mass spectrometry (Py-GC/MS). Non-catalytic pyrolysis of WPCCCR produced a large amount of oil together with gas and char. The use of both HZSM-5 and HY decreased the yields of oil and increased the yield of gas due to the additional catalytic cracking. Owing to the acidic catalytic properties of HZSM-5 and HY, catalytic Py-GC/MS analysis of WPCCCR increased the selectivity to aromatic hydrocarbons in product oil. Owing to properties of HZSM-5 having a stronger acidity and medium pore size, the catalytic pyrolysis of WPCCR over HZSM-5 produced much larger amounts of aromatic hydrocarbons than that of using HY.

• Journal of the Korean Applied Science and Technology
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• v.37 no.4
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• pp.723-732
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• 2020

The spent RHDS (Residue HydroDeSulfurization) catalyst is deactivated mainly by deposition of various contaminants such as coke, sulfur and vanadium on the surface of catalyst. To eliminate those contaminants, the following remanufacturing process was conducted. The first, heavy oil on the surface of the spent RHDS catalyst was removed by kerosene and dehydrated. The second, the high temperature incineration was carried out to eliminate coke and sulfur components deposited on the surface of spent RHDS catalyst. The third, the excessive quantity of Vanadium deposited on the surface of catalyst was removed by leaching process as follows: ultrasonic agitation was carried out at 50℃, for 10 seconds with 0.5% and 1% oxalic acid solution. The purpose of this process is to find out regenerated RHDS catalyst can be used as SCR catalyst for NOx reduction by controlling the vanadium residual content of the regenerated RHDS catalyst through leaching process. The composition of regenerated RHDS catalyst was analyzed by XRF and the NOx reduction efficiency was also measured by continuous catalytic fixed bed reactor. As the result, regenerated catalyst, with 0.5% oxalic acid, ultrasonic agitation in 10 seconds, showed the most stable NOx reduction efficiency. Also, in comparison with commercial SCR catalyst, the NOx reduction performance of regenerated catalyst was similar to that of commercial SCR catalyst at the temperature 375℃ and higher whereas was lower than commercial SCR catalyst at the temperature range between 200~250℃. Therefore, it was confirmed that the regenerated catalyst as powder form wash coated on the surface of metal corrugated substrate can be used for commercial SCR catalyst.

• 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 $900^{\circ}C$).

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.934-937
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• 2007

As skyscraper projects are emerging as a new trend in the market place, successful cost management is becoming critical issues because of their characteristics in terms of size and complexity. In addition, the lack of experience in cost management of skyscraper projects and the under-development of cost management profession pose great challenges to domestic cost managers. This paper examines major cost management issues and challenges through two major on-going skyscraper projects and discusses implications in the field of cost management.