• Journal of Electrochemical Science and Technology
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• v.3 no.4
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• pp.149-153
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• 2012

Among the various solar-hydrogen production techniques a combination of a photovoltaic (PV) and an electrolytic cell into one single system, a monolithic PV-electrolytic cell, has been suggested as a promising one in terms of efficiency and stability. In this mini-review, we describe our recent efforts on the fabrication of the monolithic PV-electrolytic cell. Particularly, we focus on the electrocatalysts for water oxidation and its fabrication method suitable for a monolithic PV-electrolytic cell. We also introduce proto-type devices with a dye-sensitized solar cell module and an InGaP/GaAs photoelectrodes.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.6
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• pp.635-641
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• 2005

Batch experiments were performed to evaluate the effect of sulfate reduction on methane production and reductive dechlorination, both compete for hydrogen with sulfate reduction. Dechlorination was inhibited by sulfate reduction at lower hydrogen concentration because their threshold values for hydrogen are similar (2 nM). Unlike methane production mainly inhibited transformation of cDCE to ethene, sulfate reduction inhibited the initial dechlorination step, PCE reduction into cDCE as well as cDCE dechlorination. The presence of sulfate eliminated methanogens as hydrogen competitor because of its high threshold value of 10 nM. When sulfate coexisted with PCE, dechlorination efficiency was not affected by the increase of seed concentration as both dechlorination and sulfate reduction were stimulated simultaneously by the increased seeding culture.

• Membrane Journal
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• v.19 no.1
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• pp.1-6
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• 2009

Hydrogen energy id the 2nd clean energy able to be produced from the abundant resources, and the products of combustion or reaction do not spread an environmental pollution. Also, the hydrogen is the chemical media easily to transport and storage as energy source. The hydrogen production technology using by water splitting through electrolysis could be usable as a permanent renewable energy system without the environmental impact. The key technology of high temperature steam electrolysis is the development of an electrolyte rapidly to conduct an oxygen or proton ion decomposed from water. Subsequently, the important technology is to keep the joining technology of an electrolyte membrane and electrode materials to affect into the current efficiency.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.3
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• pp.299-306
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• 2008

This study has been conducted to derive the bio-energy, hydrogen and methane production, from mixture of food wastewater and swine wastewater, the high strength organic wastewater and to increase effluent quality. To overcome this limitation in one-phase anaerobic process, two-phase anaerobic process combining hydrogen fermenter and methane fermenter was applied. In this system $2,323ml\;H_2/L$ was produced daily from Run II where 500 ml of heattreated sludge in methane fermenter was injected, and methane produced from methane fermenter did not show big difference regardless of the amount of returning sludge at each Run. It was concluded that the two-phase anaerobic process was the appropriat process to produce hydrogen and methane simultaneously and stably. Influent $TCOD_{Cr}$ to two-phase anaerobic process showed the range of 132~145 g/L(average 140 g/L), and effluent $TCOD_{Cr}$ range was 25~40 g/L(average 32 g/L), and organic removal efficiency showed 71~82%(average 76.3%).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.7
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• pp.563-566
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• 2013

We investigated the variation of anion exchange membrane of hydrogen generator of alkaline electrolysis. We detected the variation of elements and change of anion exchange membrane using EDS and FE-SEM. We detected two different sites of membrane because of different structure of membrane. $Sp_1$ shows that the distribution ratio of C, O, Al is 98% very higher than $Sp_2$ of 78%. Especially, the main elements of STS316 which is P, S, Fe, Ni were more detected at $Sp_2$ than $Sp_1$. We think that this result depends on the structure of membrane. This also affect the resistance, lifetime of membrane and decrease the efficiency of hydrogen production. We hope that this article is a foundation of developing of hydrogen production technology.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.6_3
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• pp.1247-1260
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• 2022

The steel industry accounts for about 5% of the total annual global energy consumption and more than 6% of the total anthropogenic carbon dioxide emissions. Therefore, there is a need to increase energy efficiency and reduce greenhouse gas emissions in these industries. The utilization of coke oven gas, a byproduct of the coke plant, is one of the main ways to achieve this goal. Coke oven gas used as a fuel in many steelmaking process is a hydrogen-rich gas with high energy potential, but it is commonly used as a heat source and is even released directly into the air after combustion reactions. In order to solve such resource waste and energy inefficiency, several alternatives have recently been proposed, such as separating and refining hydrogen directly from coke oven gas or converting it to syngas. Therefore, in this study, recent research trends on the separation and purification of hydrogen from coke oven gas and the production of syngas were introduced.

• Environmental Engineering Research
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• v.17 no.2
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• pp.89-94
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• 2012

Pyrolysis/gasification technology utilizes an energy conversion technique from various waste resources, such as biomass, solid waste, sewage sludge, and etc. to generating a syngas (synthesis gas). However, one of the major problems for the pyrolysis gasification is the presence of tar in the product gas. The tar produced might cause damages and operating problems on the facility. In this study, a gliding arc plasma reformer was developed to solve the previously acknowledged issues. An experiment was conducted using surrogate benzene and naphthalene, which are generated during the pyrolysis and/or gasification, as the representative tar substance. To identify the characteristics of the influential parameters of tar decomposition, tests were performed on the steam feed amount (steam/carbon ratio), input discharge power (specific energy input, SEI), total feed gas amount and the input tar concentration. In benzene, the optimal operating conditions of the gliding arc plasma 2 in steam to carbon (S/C) ratio, 0.98 $kWh/m^3$ in SEI, 14 L/min in total gas feed rate and 3.6% in benzene concentration. In naphthalene, 2.5 in S/C ratio, 1 $kWh/m^3$ in SEI, 18.4 L/min in total gas feed rate and 1% in naphthalene concentration. The benzene decomposition efficiency was 95%, and the energy efficiency was 120 g/kWh. The naphthalene decomposition efficiency was 79%, and the energy yield was 68 g/kWh.

• Applied Chemistry for Engineering
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• v.20 no.2
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• pp.186-190
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• 2009

This study is purposed to analyze thermodynamic properties on the hydrogen production by dimethyl ether steam reforming. Various reaction conditions of temperatures (300~1500 K), feed compositions (steam/carbon = 1~7), and pressures (1, 5, 10 atm) were applied to investigate the effects of the reaction conditions on the thermodynamic properties of dimethyl ether steam reforming. An endothermic steam reforming competed with an exothermic water gas shift reaction and an exothermic methanation within the applied reaction condition. Hydrogen production was initiated at the temperature of 400 K and the production rate was promoted at temperatures exceeding 550 K. An increase of steam to carbon ratio (S/C) in feed mixture over 1.5 resulted in the increase of the water gas shift reaction, which lowered the formation of carbon monoxide. The maximum hydrogen yield with minimizing loss of thermodynamic conversion efficiency was achieved at the reaction conditions of a temperature of 900 K and a steam to carbon ratio of 3.0.

• Environmental Engineering Research
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• v.20 no.2
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• pp.121-125
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• 2015

Biohydrogen production from food waste via dark fermentation was conducted by using mixed culture under various environmental conditions (initial pH, initial F/M ratio, initial ferrous iron ($Fe^{2+}$), and temperature condition) in batch reactor. The results revealed that the maximum hydrogen yield of $46.19mL\;H_2/g\;COD_{add}$ was achieved at the optimal conditions (initial pH 8.0, initial F/M ratio 4.0, initial iron concentration 100 mg $FeSO_4/L$ and thermophilic condition ($55{\pm}1^{\circ}C$)). Furthermore, major volatile fatty acid (VFA) productions of butyrate (765.66 mg/L) and acetate (324.69 mg/L) were detected and COD removal efficiency was detected at 66.00%. Therefore, these optimal conditions could be recommended to operate a system.

• Journal of Ceramic Processing Research
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• v.19 no.6
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• pp.514-518
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• 2018

The direct carbon fuel cell (DCFC) has attracted researcher's attention recently, due to its high conversion efficiency and its abundant fuel, carbon. A DCFC mathematical model has developed in two-dimensional, lab-scale, and considers Boudouard reaction and carbon monoxide (CO) oxidation. The model simulates the CO production by Boudouard reaction and additional electron production by CO oxidation. The Boudouard equilibrium strongly depends on operating temperature and affects the amount of produced CO and consequentially affects the overall fuel cell performance. Two different operating temperatures (973 K, 1023 K) has been calculated to discover the CO production by Boudouard reaction and overall fuel cell performance. Moreover, anode thickness of the cell has been considered to find out the influence of the Boudouard reaction zone in fuel cell performance. It was found that in high temperature operating DCFC modeling, the Boudouard reaction cannot be neglected and has a vital role in the overall fuel cell performance.