• Journal of the Korean Institute of Gas
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• v.23 no.6
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• pp.67-73
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• 2019

Hydrogen is difficult to accurately measure the amount of charge due to sudden temperature changes and pressure rise when charging the vehicle. In order to construct a hydrogen infrastructure, it is important to precisely measure the amount of charge that can be a sensitive issue in commercial transactions. In this study, the accuracy of metering of domestic hydrogen stations was evaluated as a study for metering management of hydrogen dispenser. For the experiment, we constructed metering system using master meter method and measured the flow rate in the actual hydrogen vehicle charging environment. As a result of error occurred about 10% on average, and the hydrogen loss per one charge was found to be up to 60g.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.350-355
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• 2011

The hot gas reingestion phenomenon of helicopter brings about the reduction of engine power available around in-ground. The phenomenon will vary for the conditions of ambient conditions and engine exhaust gas, the flow field associated with the downwash effect of main rotor. To verify the amount of hot gas reingestion to intake, Tests(Wind tunnel test, Flight test) or CFD could be available. At this study, the reingestion around in-ground would be predicted by numerical analysis(CFD).

• International Journal of Air-Conditioning and Refrigeration
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• v.16 no.3
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• pp.77-82
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• 2008

For heat pumps used in a cold region, it is very important to obtain appropriate heating capacity. Several studies using a variable speed compressor and an additional heater have been performed to enhance heating capacity at low ambient temperatures. However, for outdoor temperature conditions below $-15^{\circ}C$, it is still difficult to obtain enough heating capacity above the rated value. In recent studies, the application of gas injection technique into a two-stage heat pump yielded noticeable heating performance improvement at low temperature conditions. In this study, the heating performance of a two-stage gas injection heat pump with a rated capacity of 3.5 kW was measured and analyzed by varying refrigerant charge amount and EEV opening at the standard heating condition. The heating performance of the two-stage gas injection heat pump was compared with that of a two-stage non-injection heat pump. The heating capacity and COP of the two-stage gas injection heat pump were improved by 2-10% at the optimal charging condition over those of the two-stage non-injection heat pump.

• Journal of Biosystems Engineering
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• v.33 no.4
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• pp.248-252
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• 2008

An experiment was conducted in order to investigate gasification characteristics of rice husks in a fixed bed, which was a pre-step to design a continuous gasification system. Two air supply levels for gasification were chosen and their effects on the producer gas amount and producer gas composition were discussed. The main components of the producer gas were CO, $CO_2$, $O_2$, $H_2$ and THC (Total HydroCarbon). As airflow rate decreased, more producer gas was produced. The peak amount of CO, $H_2$ and THC were 28%, 7.5% and 0.68% in volume when constant airflow rate of $3.36\;m^3/s$ was used in the batch operation. About 4.5 kg of ash (9%) and condensed water including tars of 6 kg (11%) were produced from 50 kg rice husks in the gasification. Excluding the byproducts, all rice husks seemed to be transformed into producer gas. This gasification study was conducted prior to developing a continuous gasification system for biomass including agricultural byproducts.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.5
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• pp.649-658
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• 2012

In this study, the influencing factors for efficient anaerobic digestion of high strength ammonia-nitrogen wastewater removal were investigated by testing biochemical methane potential test. In the influencing factors, the trace metals which could increase activity of anaerobic microorganisms, microbial concentration and types were evaluated. In the results, trace metals supplementation showed gas production amount higher than those without addition of trace metals. Among the tested trace metals, B, Ni, and Se were preferable to gas production. In the result of gas production according to the microbial concentration, the amount of gas production was proportional to the microbial concentration. In addition, the shortest lag time and the fastest gas production rate were achieved when the highest microbial concentration was tested. granule-type microorganism produced more gas than suspended-type microorganism. In conclusion, the efficient anaerobic digestion for high strength ammonia-nitrogen wastewater removal could be achieved by applying necessary trace metals injection and high concentration granule type microorganism.

• 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.

• Journal of Korea Foundry Society
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• v.9 no.6
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• pp.474-482
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• 1989

The aim of this research is to investigate the effects of gas bubbles on the formation of spheroidal graphite in cast iron, Fe-Si-8%Mg alloy, mischmetal hydride($MmH_2$) and $CaCO_3$, which discharge various amounts of Mg, $H_2$ and $Co_2$, gases, were added to Fe-3.9% C-2.0%Si melt and the melt was innoculated with 0.3wt% of 75%Fe-Si. The spheroidal graphites and/or compacted vermicular graphites were produced with more than 0.625cc/g of Mg gas or more than 0.3125cc/g of $H_2$ gas while $CO_2$ gas did not contribute to graphite spheroidization. Nodule counts increased with the amount of Fe-Si-Mg added ; but they decreased with the amount of $MmH_2$ added because the number of effective gas bubbles decrease with the increase in Mm residual. The bull's eye structure was revealed with 0.625cc/g, 1.25cc/g of Mg and 0.3125cc/g of $H_2$ ; the ledeburite structure was revealed with more than 0.625cc/g of $H_2$.

• Journal of Hydrogen and New Energy
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• v.32 no.4
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• pp.197-204
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• 2021

Pressure swing adsorption is a purification process which can get pure hydrogen. The purification process is composed of four process: compression, adsorption, desorption and discharge. In this study the adsorption process was simulated by using the Fluent and validated with experimental results. A gas used in experiment is composed of H₂, CO₂, CH₄, and CO. Adsorption process conducted under 313 kelvin and 3 bar and bituminous-coal-based (BPL) activated carbon was used as the adsorbent. Langmuir model was applied to explain the gas adsorption. And diffusion of all the gases was controlled by micro-pore resistances. The result shows that, the most adsorbed gas was carbon dioxide, followed by methane and carbon monoxide. And carbon monoxide took the least amount of time to reach the maximum adsorption amount. The molar fraction of the off-gas became the same as the molar fraction of the gas supplied from the inlet after adsorption reached the equilibrium.

• YAKHAK HOEJI
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• v.22 no.4
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• pp.242-249
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• 1978

We have compared the panaxadiol and panaxatriol contents of white ginsengs from different countries and red ginseng, by using gas and high-pressure liquid chromatographies. Oleanolic acid contents in various ginseng species were compared by gas liquid chromatography and densitometry. Korean ginseng was found to contain greater amount of panaxadiol and panaxatriol than those of any other countries. The ginsengs from other countries, especially Chikusetzu ginseng, were found to contain far greater amount of oleanolic acid than Korean ginseng.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.6
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• pp.743-749
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• 1985

In this study the usefulness of Gas Chromatograph for the measurement of engine exhaust gas composition was confirmed. It was found that the composition of standard gas which was used for the calibration of Gas Chromatograph should not be greatly different from that of exhaust gas. Although self-evident, it cannot be overemphasized that utmost attention should be paid to prevent even a minute amount of air being mixed into the gas throughout the sampling process.