• Journal of Microbiology and Biotechnology
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• v.3 no.1
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• pp.46-50
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• 1993

In 12:12 hour light/dark cycle cultivation of D. salina 1650, maximum specific growth rate of 0.59 (l/day) and 0.35 (g-crude hydrocarbons/l/day) were obtained. The cell growth was inhibited at above 15$\times$$10^{-4} (kcal/cm^2/h)$ of light intensity in an outdoor cultivation. It was also showed that temperature is one of the critical growth parameters in the outdoor cultivation. The hydrocarbon production from D. salina 1650 seems to be partially growth related production process, and these algal hydrocarbons can be used for subsituting petroleum directly or through cracking processes. The value of weight fraction carbon of D. salina 1650 was similar to that of Botryococcus braunii and so was the hydrocarbon productivity.

• Korean Chemical Engineering Research
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• v.57 no.4
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• pp.565-574
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• 2019

Fischer-Tropsch synthesis process is a typical method for synthesizing hydrocarbons from syngas and is mainly known as iron (Fe) and cobalt (Co) catalysts. Currently, some technologies such as CTL (Coal to Liquid) and GTL (Gas to Liquid) are operated on a commercial scale depending on the products, but the research to produce light hydrocarbons and middle distillates directly has not been commercialized. Therefore, in this study, domestic studies for direct production of light hydrocarbons and middle distillates are summarized and the effect of catalyst preparation, promoter addition, zeolite combination on product selectivity is investigated.

• Transactions of the Korean hydrogen and new energy society
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• v.35 no.1
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• pp.27-33
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• 2024

In this study, we researched Ni-based bead catalysts for the catalytic thermal decomposition of light hydrocarbons. A Ni-based bead-type catalyst was prepared, and catalytic thermal decomposition performance of light hydrocarbons was evaluated. The 30Ni/Al₂O₃ catalyst exhibited the most superior performance, with the presence of both fibrous and carbon black forms on the catalyst surface. Catalytic performance was evaluated for particles sized between 150-250 and 500 ㎛, with excellent catalytic thermal decomposition properties in the 150-250 ㎛ range. After the reaction, carbon removal through collision between catalysts in the fluidized bed was observed. It was confirmed that as the particle size increases, the amount of carbon removed increases.

• Journal of Environmental Health Sciences
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• v.24 no.2
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• pp.74-79
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• 1998

This study was conducted to evaluate the surfactant solutions which influence solvent extraction from light hydrocarbon contaminated soils. Nine characteristic compounds were studied: benzene, toluene, ethylbenzene, o-xylene, mxylene, p-xylene, n-propylbenzene, 1,2,4-trimethylbenzene, and n-butylbenzene which were found in gasoline. Adsee-799 and Witbreak DRA-22 showed some extractive capacity for light hydrocarbons from soil. There was no added advantage obtained by using other surfactants in this study. No removal of contaminants from soil was observed when the surfactant concentration was 0.5 percent or below. When the surfactant concentration was 4 percent, the average recovery for some hydrocarbons was 10.8 percent, which was the best obtained at these levels. There was 10 percent surfactant contribution for methanol extraction from soil with the Witbreak DPG-482 and Witbreak DRA-22. This study provided a useful screening technique for procedures that can be used to remediate soils contaminated with light hydrocarbons.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1995.05a
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• pp.31-40
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• 1995

The degradation of aqueous chlorinated compounds such as trichloroethylene (TCE), tetrachloroethylene (PCE) and dichloroacetic acid (DCA) to $CO_2$ and HCl was accomplished in the presence of UV light and suspended TiO$_2$ slurries. The decomposition of chlorinated hydrocarbons at 253.7 m irradiation was more effective than that at 360 nm irradiation. Our results show that 253.7 nm irradiation alone can be used for decomposing some chlorinated hydrocarbons such as PCE and TCE.

• Journal of the Korean Chemical Society
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• v.55 no.5
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• pp.824-829
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• 2011

In Fischer-Tropsch Synthesis, because of few reactants ($H_2$, CO), scarce operating parameters affected on efficiency especially the selectivity of products. In this research, effect of operating parameters on the selectivity of Co-Mn-$TiO_2$ Fischer-Tropsch synthesis catalyst were studied by design of experimental procedure and Taguchi method. According to this research, interactions between operating factors have a crucial effect on light products selectivity. Among these interactions, (temperature${\times}$feed ratio) has the main influence on light hydrocarbons selectivity. It was concluded that temperature and feed ratio ($H_2$/CO) were the most integral operating parameters for much greater selectivity of light hydrocarbons.

• Journal of Microbiology and Biotechnology
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• v.1 no.2
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• pp.111-115
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• 1991

The green alga, Dunaliella salina under fed-batch cultivation produced 51.12 mg of hydrocarbon per liter with maintaining 0.313 (g dry wt/l). About 20% of hydrocarbon production yield based on dry biomass was obtained from both batch and fed-batch processes. Optimum culture conditions of light intensity, pH and salt concentration were obtained as 0.0080 (kJ/$cm^2$/h), 8.0 and 1.4 (g of NaCl/l), respectively by response surface analysis. The production of hydrocarbons in D. salina was closely correlated to cell growth. Fed-batch cultivation produced more hydrocarbons and maintained better cell growth than a batch process.

• Journal of Environmental Health Sciences
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• v.23 no.4
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• pp.82-90
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• 1997

This study was conducted to establish an ideal condition for obtaining maximum extraction efficiencies using an array of soil types and under a wide variety of conditions. Nine characteristic compounds were studied: benzene, toluene, ethylbenzene, o-xylene, m-xylene, p-xylene, n-propylbenzene, 1,2,4-trimethylbenzene, and n-butylbenzene which were found in gasoline. Increasing the moisture content resulted in decreased recovery, and recovery of hydrocarbons from wet soils was significantly lower than from dry soils. For the batch extraction process, 4 hours of extraction time was sufficient to give optimum recovery of the contaminants. With methanol as an extraction solvent, maximum recovery time appeared to be reached quicker for BTEX components than with 2-propanol. The 2 to 1 ratio of solvent/soil was chosen as a compromise to provide for the indicated minimum solvent use and high extraction efficiency. The 0.4 mg/g soil contamination was adequate to show quantitative recovery. The percent recovery of BTEX was concentration dependent more than the semivolatile compounds. Methanol and 2-propanol consistently gave higher efficiency than water. Methanol was superior to 2-propanol in removing contaminants from silty clay loam soil. Using the most efficient extraction procedure, the average recovery of the light hydrocarbons from the three soils was 66 percent. Recoveries were also dependent on soil type, solvent type, extraction time, solvent amount, contaminant concentration, and compounds volatility. This study provided a useful screening technique for procedures that can be used to remediate soils contaminated with light hydrocarbons.

• Journal of Environmental Science International
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• v.27 no.11
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• pp.967-974
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• 2018

In this study, we evaluated the photocatalytic oxidation efficiency of aromatic volatile hydrocarbons by using $WO_3$-doped $TiO_2$ nanotubes (WTNTs) under visible-light irradiation. One-dimensional WTNTs were synthesized by ultrasonic-assisted hydrothermal method and impregnation. XRD analysis revealed successful incorporation of $WO_3$ into $TiO_2$ nanotube (TNT) structures. UV-Vis spectra exhibited that the synthesized WTNT samples can be activated under visible light irradiation. FE-SEM and TEM images showed the one-dimensional structure of the prepared TNTs and WTNTs. The photocatalytic oxidation efficiencies of toluene, ethylbenzene, and o-xylene were higher using WTNT samples than undoped TNT. These results were explained based on the charge separation ability, adsorption capability, and light absorption of the sample photocatalysts. Among the different light sources, light-emitting-diodes (LEDs) are more highly energy-efficient than 8-W daylight used for the photocatalytic oxidation of toluene, ethylbenzene, and o-xylene, though the photocatalytic oxidation efficiency is higher for 8-W daylight.

• Journal of the Korean Society of Combustion
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• v.4 no.2
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• pp.23-33
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• 1999

A turbulent non-premixed ethylene flame, which was set up in a vertical wind tunnel, was examined to understand the effect of turbulent mixing on formations of soot and gaseous species in the flames. Temperature and velocity profiles were measured using uncoated thermocouples and LDV system. Gaseous samples were withdrawn by using a water cooled stainless iso-kinetic gas sampling probe. The samples for inorganic compounds and light hydrocarbons were collected with sampling bottles and were analyzed by a gas chromatography. The samples for aromatic hydrocarbons were collected on a sorbent tube and were analyzed on a GC/MS system. Some of main results were followed. CO and $CO_2$ were measured relatively in early part of flame and the concentration of CO was greater than that of $CO_2$ all over the early flame region due to the scavenging of the oxidizing species OH by soot particles. Aromatic hydrocarbons were measured at x/D=122 along the radial direction and main important species were benzene, xylene, toluene, styrene, indene, naphthalene. The peak points of these compounds occurred at r/D=0.8 apart from the center of flame, around in which the concentration of $C_2H_2$ decayed relatively rapidly from the maximum value.