• Transactions of the Korean hydrogen and new energy society
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• v.20 no.4
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• pp.337-343
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• 2009

Noncatalytic partial oxidation of methane for producing synthesis gas was studied in a lab-scale experimental apparatus. Partial oxidation developed for high-temperature, fuel-rich combustion and it is exothermic process. but Steam reforming and Caron reforming is highly endothermic process to need much energy. Noncatalytic partial oxidation of methane is affected by temperature and equivalent ratio, so we studied effect about composition of synthesis gas at lab scale reactor. We used electronic heater to control the temperature of reactor. The quality of synthesis gas is improved and reduced heat value to require at Noncatalytic partial oxidation because the reacting temperature is lower at oxy condition.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.250.1-250.1
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• 2014

A multicusp ion source has been used widely in negative hydrogen cyclotrons mainly for radioisotope productions. The ion source is designed to have cusp geometries of magnetic field inside plasma chamber, where ions are confining and their mean lifetimes increase. The magnetic confinement produced a number of permanent magnetic poles helps to increase beam currents and reduce the emittance. Therefore optimizing the number of magnets confining more ions and increasing their mean lifetime in plasma has to be investigated in order to improve the performance of the ion source. In this work a numerical simulation of the magnetic flux density from a number of permanent magnets is carried to optimize the cusp geometries producing the highest plasma density, which is clearly indicated along the full-line cusp geometry. The effect of magnetic fields and a number of poles on the plasma structure are investigated by a computing tool. The electron confinement effect becomes stronger and the density increases with increasing the number of poles. On the contrary, the escape of electrons from the loss cone becomes more frequent as the pole number increases [1]. To understand above observation the electron and ion's trajectories along with different cusp geometries are simulated. The simulation has been shown that the optimized numbers of magnets can improve the ion density and uniformity.

• Transactions of the Korean hydrogen and new energy society
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• v.11 no.4
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• pp.149-159
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• 2000

This paper is concerned with the performence of a steam reformer for 25kW class MCFC, which is compared with the theoretically calculated results at various operating conditions. The theoretical $H_2$ production amount and $CH_4$ conversion rate are calculated with variations of temperature and steam/carbon (S/C) ratio using fortran program, and the actual values are measured from flowmeter and gas chromatography. As a result of the comparison of theoretical and actual values, the theoretical $H_2$ production amount is calculated by $24.4m^3/hr$ at the normal operating condition(LNG $9m^3/hr$, S/C ratio 5, absolute pressure $2.77kg/cm^2$, $610^{\circ}C$), but the actual production amount is only $19.4m^3/hr$, which is 79.5% of the theoretical value. Nevertheless, at the normal operating condition, the reformer for 25kW class MCFC performed well for a 2,100 hr long run operation, constantly producing $H_2$.

• Transactions of the Korean hydrogen and new energy society
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• v.29 no.6
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• pp.668-679
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• 2018

Experimental and numerical data were compared through a counterflow burner for the characteristic of basic flame about SNG- C11. In order to use the numerical mechanism accurately, the validation was carried out at strain rate ($a_g=30$, $120s^{-1}$) and the UCSD model showed satisfactory results. The effective Lewis number of the extinction boundary, and the behavior of extinction for the symmetric flames of the SNG-C11, could be explained through the trend of $Le_V$, and the flame of the extinction condition was inspected by the major species, key radicals and the chemical reaction paths. The interactions phenomenon in the merged flames has chemical reaction path for producing $HO_2$ were generated at stagnation point. It can be expected the one of major factors in interaction phenomenon.

• Journal of the Korean institute of surface engineering
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• v.55 no.6
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• pp.319-327
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• 2022

Ion exchange membranes have been developed from laboratory tools to industrial products with significant technical and trade impacts in the last 70 years. Today, ion exchange membranes are successfully applied for water and energy for different electro-membrane processes. Hydrogen could be produced by electrochemical water splitting using renewable energy, for example, solar, biomass, geothermal and wind energy. This review briefly summarizes the recent studies reporting the state-of-the-art anion-exchange membrane water electrolysis, especially focusing on the enhancement of the durability of anion-exchange membranes. Anion-exchange membrane water electrolysis could be used as inexpensive non-noble metal electrocatalysts that are capable of producing low cost of hydrogen. However, the main challenge of anion-exchange membrane water electrolysis is to increase the performance and durability. In this mini review, the limiting factors of the durability and the technology enhancing the durability will be discussed for anion exchange membrane water electrolysis.

• Journal of the Korean institute of surface engineering
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• v.56 no.6
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• pp.427-436
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• 2023

In the industry, it is recognized that human activities significantly lead to a large amount of wastewater, mainly due to the increased use of water and energy. As a result, the growing field of wastewater resource technology is getting more attention. The common technology for hydrogen production, water electrolysis, requires purified water, leading to the need for desalination and reprocessing. However, producing hydrogen directly from wastewater could be a more cost-effective option compared to traditional methods. To achieve this, a series of first-principle computational simulations were conducted to assess how waste nutrient ions affect standard electrolysis catalysts. This study focused on understanding the adsorption mechanisms of byproducts related to the oxygen evolution reaction (OER) in anion exchange membrane (AEM) electrolysis, using Co₃O₄ as a typical non-precious metal catalyst. At the same time, efforts were made to develop a comprehensive free energy prediction model for more accurate predictions of OER results.

• KSBB Journal
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• v.20 no.6
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• pp.413-417
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• 2005

The purple sulfur phototrophic bacterium, Thiocapsa roseopersicina NCIB 8347 has been studied on hydrogen production and cell growth under different culture conditions, such as light source, light intensity, and growth temperature. T. roseopersicina showed maximum cell growth of 1.38 and 1.42 g-DCW/L under 7.5-10 klux of halogen and fluorescent light, respectively, and produced maximum amount of hydrogen with values of 0.90 and 0.48 $mL-H_2/mg$-DCW under the irradiation of 10 klux of halogen and fluorescent light, respectively. The optimum growth temperature for hydrogen production was $26^{\circ}C$, and hydrogen production rate was lowered over $30^{\circ}C$. When T. roseopersicina was grown photoheterotrophically under irradiation of 8-9 klux of halogen lamp, the generation time was 4.2 hr. The strains started producing hydrgen from the middle of the logarithmic growth phase and continued until succinate concentration leveled out.

• Membrane Journal
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• v.33 no.6
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• pp.352-361
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• 2023

Steam methane reforming is currently the most widely used technology for producing hydrogen, a clean fuel. Hydrogen produced by steam methane reforming contains impurities such as carbon monoxide, and it is essential to undergo an appropriate post-purification step for commercial usage, such as fuel cells. Recently, membrane separation technology has been gaining great attention as an effective purification method; in this study, we evaluated the feasibility of using commercial polysulfone membranes for biogas upgrading to separate and recover hydrogen from a hydrogen/carbon monoxide gas mixture. Initially, we examined the physicochemical properties of the commercial membrane used. We then conducted performance evaluations of the commercial membrane module under various conditions using mixed gas, considering factors such as stage-cut and operating pressure. Finally, based on the evaluation results, we carried out simulations for process design. The maximum H₂ permeability and H₂/CO separation factor for the commercial membrane process were recorded at 361 GPU and 20.6, respectively. Additionally, the CO removal efficiency reached up to 94%, and the produced hydrogen concentration achieved a maximum of 99.1%.

• Journal of Microbiology and Biotechnology
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• v.10 no.1
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• pp.1-7
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• 2000

Bioconversion of fumarate to succinate was anaerobically conduced in a synthetic medium containing glycerol as a hydrogen donor and fumarate as a hydrogen acceptor. We investigated the effects of pH, carbon and nitrogen sources, conversion substrate, and other culture conditions on the production of succinate using a nwely isoloated Enterococcus facalis PKY1. Addition of a variety of carbonates to the medium significantly increasd the rates of production of succinate. The production of succinate and cell growth were relatively satisfactory in the pH range of 7.0-7.6. By using glycerol as a hydrogen donor, high purity succinate was produced with few byproducts. Yeast extract as a sole nitrogen source was the most effective for producing succinalte. As a result, the optimum condition of biconversion was obtained at a medium containing 20g/I glycerol, 50 g/l fumarate, 15 g/l yeast extract, 10 g/l $K_2HPO_4$, 1 g/I NaCl, 50ppm $MgCl_2{\cdot}6H_2O$, 10ppm $FeSo_4{\cdot}7H_2O$, and 5 g/I $Na_2CO_3$ at pH 7.0-7.6. Under the optimum condition, a succinate concentration of 153 g/I was produced in 36 h. The total volumetric production rate and the molar yield of succinate were 4.3 g/l/h and 85%, respectively.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.5
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• pp.621-629
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• 2007

This study intends to investigate the characteristics of the foul smell of sewer pipes near large apartment complexes as complaints about offensive odors have drastically increased in urban residential areas. Targeting apartments where people actually complained about foul orders, the study result revealed that components in the smell of the water-purifier tank of the target apartment were very similar to those of sewage treatment plants and night soil treatment plants. Measuring components of odors inside the management layer of tank showed that the concentration of hydrogen sulfide was 10ppm, which is approximately 160 times the safety standard of 0.06ppm; the concentration of mercaptan was 0.9ppm, which is about 220 times the safety standard of 0.004ppm. The source materials of foul odors were discharged outside through ducts, and those households living near outlets producing bad smell complain that it gets worse depending on the air pressure or wind direction and strength, and they could not even open windows. As well, these source materials were transferred by discharge pumps to public sewer pipes outside the apartment complex. While discharge pumps starts operating, they remain on the sewer pipe and then begin to spread over to roads through small openings of manholes on the road. Then, the smell offends passers-by and residents near the road, leading to a lot of complaints. The study results suggest that, among the sources of foul odors in sewer pipes of residential areas, especially those from the water-purifier tank of large apartments, hydrogen sulfide should be the main target for follow-up treatment.