• Journal of Aquaculture
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• v.13 no.4
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• pp.303-308
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• 2000

Effects of the sediments on water quality, and the consequent survival and growth of cultured fleshy prawns, Penaeus chil1ensis were determined under selected sediment types for 6 weeks. Dissolved oxygen was 5.1-5.9 mgll in both the sediments containing sand alone, and soft sand (50%) and mud (50%). It decreased to 4.6 mgll in the mud after 6 weeks. Nitrite, ammonia and hydrogen sulfide of the seawater were 0.07-0.12, 0.16-0.29 and 0.009~0.014 mgll in both the sediments containing sand alone, and soft sand (50%) and mud (50%). The values, however, increased to 0.15, 0.36 and 0.018 mgll in the mud sediment, respectively. Survival of the prawn was below 60% in bare and mud sediments. It was above 70% in both the sediments containing sand alone, and soft sand (50%) and mud (50%). Growth and food efficiency of the prawn were significantly lower in the 100 % sand than in the sediment containing soft sand (50%) and mud (50%).

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.2
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• pp.206-212
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• 2011

The effect of process parameters on $H_2$ production from water vapor excited by HF ICP has been qualitatively examined for the first time. With the increase of ICP power, characteristics of $H_2$ production from $H_2O$ dissociation in plasma was divided into 3 regions according to both reaction mechanism and energy efficiency. At the edge of region (II) in the range of middle ICP power, energy effective hydrogen production from $H_2O$ plasma can be achieved. Furthermore, within the region (II) power condition, heating of substrate up to $500^{\circ}C$ shows additional increase of 70~80% in $H_2$ production compared to $H_2O$ plasma without substrate heating. This study have shown that combination of optimal plasma power (region II) and wall heating (around $500^{\circ}C$) is one of effective ways for $H_2$ production from $H_2O$.

• Korean Chemical Engineering Research
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• v.45 no.5
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• pp.415-423
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• 2007

Photocatalytic water splitting (PWS) is the most promising technology to produce $H_2$ energy directly from renewable water and solar light. In spite of the remarkable progress made in the last decade, there are still many technical challenges remaining particularly in finding new photocatalytic materials with high efficiency and durability. This article discusses the application of nanocomposite materials in search of new photocatalytic materials for solar hydrogen production from water. It has been demonstrated that smart combination and modification of known materials and functions could be fruitful approach for the purpose.

• Transactions of the Korean hydrogen and new energy society
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• v.13 no.2
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• pp.127-134
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• 2002

A Study on the application of ultrasonic with high frequency is carried out as a plan to rise the efficiency of the hydrogen fuel production in an electrolysis of water. KOH is selected as an electrolyte and concentrations are 0 %, 10 %, 20 %, and 30%. The solvent is city water. A measurable device of buoyancy by an electronic balance and a measurable device of voltage with a sensor of pressure are planned newly as a measuring device to measure the quantity of hydrogen production. An ultrasonic transducer with high frequency of 2 MHz is selected to give them the ultrasonic forcing. In results, it is clarified that ultrasonic influences the decrease of overpotential in the electrolytic solution. And basic data according to the pole interval and the temperature are obtained.

• KSBB Journal
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• v.15 no.3
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• pp.268-273
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• 2000

A microbiological hydrogen production process was optimized. Anaerobic photosynthetic bacteria like Rhodospirillum rubrum which is known to produce hydrogen from carbon monoxide efficiently and remove sulfur was used. To evaluate the potenital of this microorganism the optimization of media fermentation condition light intensity and light requirement for CO conversionwas tried in batch cultures and the continuous fermenter was also applied for this process. The gas residence time on CO conversion was sought out to get high conversion of carbon monoxide to hydrogen. Through this study the possibility of microbial synthtics gas concersion process was proposed.

• Journal of the Korean Institute of Gas
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• v.15 no.2
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• pp.63-68
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• 2011

As an effective utilization of biomass, organic wastes and coal, attention has been made to use syngas to a reciprocating engine to generate power. However, significant component variation of syngas depending upon origin and gasification conditions, and its lower heating value than that of LPG and CNG can create difficulties in stable engine operation. Thus it is necessary to address these issues in order to successfully develop power generation engines. As a primary step to resolve these problems, effects of H2 content variation in syngas on engine performance and emission characteristics were discussed in this study. The results show that as H2 % in syngas increases, more stable combustion was achieved with retarded MBT spark timing and engine efficiency becomes maximum with syngas of 10% H2. In addition, NOx emission increased while THC emission decreased as H2 % rises in the syngas.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.3
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• pp.128-134
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• 2016

An analysis of the main factors and its degree of impact on power production is performed against the landfill gas power plant in S landfill site. The number of normal operation (50 MWh & 24 hr) days was 70.9% to the total number of operation days from 2007 to 2014, and the percentage of the actual power production was 79.3% of 3,428,400 MW which is the theoretical maximum estimation. The ratio of factors that accounted for the efficiency of power production are: 44.0% of repairing of the defect and regular servicing, 37.4% of cut-down operation due to hydrogen sulfide, and 18.6% of air pre-heater washing, respectively. Yet, considering that the cut-down operation due to hydrogen sulfide was carried out for only two years, the high concentration of hydrogen sulfide was the most influential factors on landfill gas power production. The long-term power production was analyzed as 35.9 MWh in 2018, and the constant drop is anticipated, resulting in 16.6 MWh by 2028, and under 8.4 MWh in 2038.

• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.410-415
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• 1996

It is well known that the heavy water separation process using hydrogen isotope exchange reaction over the platinum catalyst is the most efficient. In this study, the Pt/silicalite catalysts were prepared and characterized by hydrogen adsorption in order to develop the hydrophobic platinum catalyst for hydrogen isotope exchange reaction. Silicalite was synthesized as support material and it was verified that silicalite is more hydrophobic than activated carbon and ZSM-5. Also the platinum was loaded on silicalite by conventional impregnation and ion-exchange method respectively. The platinum dispersion of Pt/silicalite catalysts was measured through hydrogen adsorption experiment. The dispersion is very low in the catalyst prepared by the impregnation method while it is very high with limited platinum content in the catalyst prepared by the ion-exchange method.

• 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%.

• Clean Technology
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• v.26 no.2
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• pp.96-101
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• 2020

In this paper, the commercial feasibility of trigeneration, producing heat, power, and hydrogen (CHHP) and using biogas derived from macroalgae (i.e., seaweed biomass feedstock), are investigated. For this purpose, a commercial scale trigeneration process, consisting of three MW solid oxide fuel cells (SOFCs), gas turbine, and organic Rankine cycle, is designed conceptually and simulated using Aspen plus, a commercial process simulator. To produce hydrogen, a solid oxide fuel cell system is re-designed by the removal of after-burner and the addition of a water-gas shift reactor. The cost of each unit operation equipment in the process is estimated through the calculated heat and mass balances from simulation, with the techno-economic analysis following through. The designed CHHP process produces 2.3 MW of net power and 50 kg hr^-1 of hydrogen with an efficiency of 37% using 2 ton hr^-1 of biogas from 3.47 ton hr^-1 (dry basis) of brown algae as feedstock. Based on these results, a realistic scenario is evaluated economically and the breakeven electricity selling price (BESP) is calculated. The calculated BESP is ¢10.45 kWh^-1, which is comparable to or better than the conventional power generation. This means that the CHHP process based on SOFC can be a viable alternative when the technical targets on SOFC are reached.