• 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.

• Journal of Hydrogen and New Energy
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• v.32 no.4
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• pp.271-276
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• 2021

Although the development of electric vehicles or electric commercial vehicles is underway in Korea, most companies are seeking to enter the global market because it is difficult to expand their business only in the domestic market. In addition, it is recognized that the country has difficulties in responding to regulations or related procedures when entering overseas markets, and due to such difficulties, it is not possible to gain opportunities to enter the market and gain the technical advantage. Therefore, it is necessary to support individual companies to overcome the difficulties of promoting and exporting products by establishing a pre-cycle support environment for technology development so that development parts can be installed in small electric commercial vehicles. Therefore, this study tried to understand the necessity and factors of small electric commercial vehicles for major ASEAN countries, and as a result, most of them raised the urgency and necessity of joint research.In addition, human resource development, government support, and technical support were suggested as the necessary factors for the study.

• Journal of Hydrogen and New Energy
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• v.32 no.4
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• pp.236-244
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• 2021

Fuel cell systems for medium duty truck require high power demands under driving. Since high power demands results in significant heat generation, thermal management is crucial for the performance and durability of medium duty truck. Therefore, various configurations of dual stacks with cooling systems are investigated to understand appropriate thermal management conditions. The simulation model consists of a dynamic fuel cell stack model, a cooling system model equipped with a controller, and the mounted controller applies a feedback controller to control the operating temperature. Also, In order to minimize parasitic power, the comparison of the cooling systems involved in the arrangement was divided into three case. As a result, this study compares the reaction of fuel cells to the placement of the cooling system under a variety of load conditions to find the best placement method.

• Journal of Hydrogen and New Energy
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• v.32 no.4
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• pp.277-284
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• 2021

This paper deals with multi-objective optimization using response surface method to improve the hydraulic performances of a 2 vane pump for wastewater treatment. For analyzing the internal flow field in the pump, steady Reynolds-averaged Navier-Stokes equations were solved with the shear stress transport turbulence model as a turbulence closure model. The impeller and volute variables were defined in the shape of the 2 vane pump. The objective functions were set to satisfy the total head at the design flow rate as well as to improve the efficiency. The hydraulic performance of the optimally designed shape was verified by numerical analysis results.

• Journal of Hydrogen and New Energy
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• v.30 no.5
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• pp.418-427
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• 2019

Activated carbon was synthesized from bamboo charcoal by KOH activation at various temperatures for electrochemical double layer capacitor applications. The micro-structural and surface properties of all the samples were characterized by X-ray diffraction, scanning electron microscopy and N2 adsorption/desorption isotherm method. The electrochemical properties of the activated bamboo charcoal were examined by cyclic voltammetry in the potential window of -1.0 to 0.2 V in 6 M KOH electrolyte at different scan rates. An electrode made from the sample activated with 7.5 M KOH and heat treated at $750^{\circ}C$ for 3 h gave a maximum capacitance of 553 F/g at 1 mV/s and 450 F/g at 10mV/s.

• Journal of Hydrogen and New Energy
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• v.30 no.5
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• pp.436-447
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• 2019

The circulating fluidized bed boiler has an advantage that can burn a variety of fuels from low-grade fuel to coal. In this study, for the design of a circulating fluidized bed boiler using wood pellets, a circulating fluidized bed combustion test device using no external heater was manufactured and used. According to the increase of co-combustion rate with wood pellet, combustion fraction and heat flux by combustor height were measured and pollutant emission characteristics were analyzed. In terms of combustibility, the effect on primary and secondary air ratio were also studied. In addition, as a result of analysis of the effect of corrosive nanoparticles on the combustion of coal with wood pellets, it was confirmed that coal is mostly composed of Ca and S, whereas wood pellets are mostly composed of K, Cl, and Na.

• Journal of Hydrogen and New Energy
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• v.30 no.5
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• pp.448-454
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• 2019

This paper presents a high-efficiency design technique for developing the serialized models of a single-channel pump based on the diameter, flow rate and head as the main performance parameters. The variation in pump performance by changing of the single-channel pump geometry was predicted based on computational fluid dynamics (CFD). Numerical analysis was conducted by solving three-dimensional steady Reynolds-averaged Navier-Stokes equations with the shear stress transport (SST) turbulence model. The tendencies of the hydraulic performance depending on the pump geometry scale were analyzed with the fixed rotational speed. These performances were expressed and evaluated as the functionalization for designing the serialized models of a single-channel pump in this work.

• Journal of Hydrogen and New Energy
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• v.31 no.6
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• pp.558-563
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• 2020

Hydrogen is attracting attention as an alternative energy source as an eco-friendly fuel without emitting environmental pollutants. In order to use hydrogen as an energy source, technologies such as hydrogen production and storage must be used, and new storage methods are being studied. In this study, the behavior of hydrogen in the storage tank were numerically studied under high-pressure hydrogen discharge conditions in a Type III hydrogen tank. Numerical results were compared with the experimental value and the results were quantitatively analyzed to verify the numerical implementation. With the results of pressure and temperature values under a given discharge condition, the Redich-Kwong gas model showed the adequate models with the smallest error between numerical and experimental results.

• Journal of Hydrogen and New Energy
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• v.31 no.6
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• pp.571-577
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• 2020

Thermal analysis was performed for a cold box of a hydrogen liquefaction pilot plant with 0.5 ton/day capacity. The pilot plant has adopted a hydrogen liquefaction process using two-stage helium Brayton cycle with precooling of liquid nitrogen. The cold box for hydrogen liquefaction has generally vacuum insulation but inevitable heat invasion by conduction and radiation exists. The heat loads were calculated for cold box internals according to multilayer insulation emissivity. Total heat load of 181.7 W is estimated for emissivity of 0.03 considered in field condition.

• Journal of Hydrogen and New Energy
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• v.31 no.6
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• pp.614-621
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• 2020

Recently, as the fine dust is increased and the emission regulations of diesel engines are strengthened, interest in diesel soot filtration devices is rapidly increased. In particular, there is a demand for technology development for higher efficiency of diesel exhaust gas after-treatment devices. As part of this, many studies conducted to increase the exhaust gas treatment efficiency by improving the flow uniformity of the exhaust gas in the DPF and reducing the pressure drop between the inlet and outlet of disel particle filter (DPF). In this study, computational fluid dynamics (CFD) simulation was performed when exhaust gas flows into the canning reduction device equipped with a 13" asymmetric DPF in order to maintain the flow uniformity in the diesel exhaust system and reduce the pressure. In particular, a study was conducted to find the geometry with the smallest pressure drop and the highest flow uniformity by simulating the DPF I/O ratio, exhaust gas temperature, inlet-outlet pressure and flow uniformity according to the geometry and hole size of distributor.