• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.697-704
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• 2015

This study was carried out to assess bioenergy conversion efficiency by biogas and solid fuel production in the cattle feedlot manure discharged from beef cattle barn. Feedlot manure was sampled from the cattle farmhouse located in Yong-in, Gyeonggi during the mid-fattening stage, periodically. The chemical characteristics, BMP (Biochemical methane potential) and HV (Heating values) of feedlot cattle manures were analyzed. Total solid contents of cattle feedlot manure were in the range of 29.98~44.28%, and volatile solid contents were in the range of 23.53~24.47%. In the anaerobic digestion of cattle feedlot manure, the methane production potential has increased from 0.141 to $0.187Nm^3kg^{-1}-VS_{added}$. The methane production of fresh cattle feedlot manure showed the range $0.141{\sim}0.187Nm^3kg^{-1}$-Manure (average $0.047Nm^3kg^{-1}$-Manure), the LHVs (lower heating values) of the produced methane were in the range of $316{\sim}560kcalkg^{-1}$-Manure (average $400kcalkg^{-1}$-Manure). In the direct combustion of fresh cattle feedlot manure, the LHVs were measured in the range of $747{\sim}1,271kcalkg^{-1}$-Manure (average $916kcalkg^{-1}$-Manure), and LHVs of solid fuel which have the water content of 20% were in the range of $2,694{\sim}2,876kcalkg^{-1}$-Manure (average $2,791kcalkg^{-1}$-Manure). Then, the drying energy of average $443kcalkg^{-1}$-Manure was consumed in the production of solid fuel which has a water content of 20%. Therefore, the direct combustion of cattle feedlot manure showed about 2.3 times higher LHV than the LHV of methane produced by anaerobic digestion. And LHV of solid fuel was about 6.0 times higher than the LHV of methane produced by anaerobic digestion. Then, the production of solid fuel presented more bioenergy conversion efficiency than the biogas production in the bioenergy use of cattle feedlot manure.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.5
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• pp.12-18
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• 2014

A study of gas generator Fuel-Rich propellant for air-breathing propulsion system was performed in this paper. General solid propellant comprises a mean of 60% or more oxidizing agents. but, to develop the fuel-rich solid propellant increased the content of the metal fuel and reduced the content of the oxidizing agents by approximately 30%. Very high amount of heat per volume of fuel into the metal having the Boron was used. Amorphous Boron Powder was applied to propellant as beads type and it allowed to design more amount of metal fuel in the fuel-rich propellant. And the Combustion characteristics and properties of fuel-rich solid propellant according to the Boron-bead sizes were confirmed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1995.11a
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• pp.3-8
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• 1995

An experimental investigation was conducted in order to figure out the multiple fire effects on the combustion efficiency and fuel properties of the solid fuel ramjet. Pure HTPB and metallized $B_4$C/HTPB fuel were studied. Fuel property effects were analyzed by using differential scanning calorimetry, The thermal or mechanical properties of the fuel grain were not affected and the combustion efficiency was a little increased.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.1
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• pp.12-19
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• 2022

The propellants used in the gas generator of the ducted rocket are fuel-rich propellants, which contain an excessive amount of metal fuel and a small amount of oxidizing agent compared to general solid rocket propellants. In this paper, boron powder and MgAl(Magnesium-Aluminium alloy) were applied to produce fuel-rich propellants. The optimum formulation was determined by characterizing these metal fuel-rich propellants. Analysis of combustion products in the gas generators confirmed that the fuel-rich propellants containing fine boron powder itself instead of boron-bead could be useful in gas generators.

• Journal of the Korean Ceramic Society
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• v.52 no.5
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• pp.350-355
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• 2015

To develop ceramic composite anodes of solid oxide fuel cells without metal catalysts, a small amount of barium carbonate was added to an $(La_{0.8}Sr_{0.2})(Cr_{0.5}Mn_{0.5})O_3(LSCM)$ - YSZ ceramic composite anode and its catalytic effects on the electrode performance were investigated. A barium precursor solution with citric acid was used to synthesize the barium carbonate during ignition, while a barium precursor solution without citric acid was used to create hydrated barium hydroxide. The addition of barium carbonate to the ceramic composite anode caused stable fuel cell performance at 1073 K; this performance was higher than that of a fuel cell with $CeO_2$ catalyst; however, the addition of hydrated barium hydroxide to the ceramic composite anode caused poor stability of the fuel cell performance.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.226-240
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• 2023

This paper provides an overview of the trends and future directions in the development of anode materials for solid oxide fuel cells (SOFCs) using hydrocarbons as fuel, with the aim of enabling a decentralized energy supply. Hydrocarbons (such as natural gas and biogas) offer promising alternatives to traditional energy sources, as their use in SOFCs can help meet the growing demands for energy. We cover several types of materials, including perovskite structures, high-entropy alloys, proton-conducting ceramic materials, anode on-cell catalyst reforming layers, and anode functional layers. In addition, we review the performance and long-term stability of cells based on these anode materials and assess their potential for commercial manufacturing processes. Finally, we present a model for enhancing the applicability of fuel cell-based power generation systems to assist in the realization of the H₂ economy as the best practice for enabling distributed energy. Overall, this study highlights the potential of SOFCs to make significant progress toward a sustainable and efficient energy future.

• Journal of Mechanical Science and Technology
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• v.17 no.10
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• pp.1572-1582
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• 2003

Hybrid rocket combustion has a manifestation of stable response to the perturbations compared to solid propellant combustion. Recently, it has revealed that the low frequency combustion instability about 10 Hz was occurred mainly due to thermal inertia of solid fuel. In this paper, the combustion response function was theoretically derived by use of ZN (Zeldovich-Novozhilov) method. The result with HTPB/LOX combination showed a quite good agreement in response function with previous works and could predict the low frequency oscillations with a peak around 10 Hz which was observed experimentally. Also, it was found that the amplification region in the frequency domain is independent of the regression rate exponent n but showed the dependence of activation energy. Moreover, the response function has shown that the hybrid combustion system was stable due to negative heat release of solid fuel for vaporization, even though the addition of energetic ingredients such as AP and Al could lead to increase heat release at the fuel surface.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.129-132
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• 2007

Advanced structure of metal-supported solid oxide fuel cells was devised to overcome sealing problem and mechanical instability in ceramic-supported solid oxide fuel cells. STS430 whose dimensions were 26mm diameter, 1mm thickness and 0.4mm channel width was used as metal support. Thin ceramic layer composed of anode(Ni/YSZ) and electrolyte(YSZ) was joined with STS430 metal support by using a cermet adhesive. $La_{0.8}Sr_{0.2}Co_{0.4}Mn_{0.6}O_{3}$ perovskite oxide was used as cathode material. It was noted that oxygen reduction reaction of cathode governed the overall cell performance from oxygen partial pressure dependance.

• 한국연소학회:학술대회논문집
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• 2003.12a
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• pp.167-173
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• 2003

An experimental study on the behavior of droplets impinging on a solid flat surface was carried out in the present study. Breakup of a liquid droplet impinging on a solid surface has been investigated experimentally for various fuels with different properties. The fuel temperature and incident angle were chosen as major parameters. And fuel temperature and incident angle varied in the range from $-20^{\circ}C$ to $30^{\circ}C$ and from $30^{\circ}$ to $60^{\circ}$, respectively, were investigated. It was found that the variation of fuel temperature influences upon droplet mean diameter which were bounced out from the solid surface. As the increases of incident angle, the break-out mass flow rate increases. This causes the decrease of liquid film flow rate. The larger incident angle gives less liquid film flow rate.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.51-54
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• 2008

This study aims to devise and analyze a power generation system combining the solid oxide fuel cell and oxy-fuel combustion technology. The fuel cell operates at an elevated pressure, a constituting a SOFC/gas turbine hybrid system. Oxygen is extracted from the high pressure cathode exit gas using ion transport membrane technology and supplied to the oxy-fuel power system. The entire system generates much more power than the fuel cell only system due to increased fuel cell voltage and power addition from oxy-fuel system. More than one third of the power comes out of the oxy-fuel system. The system efficiency is also higher than that of the fuel cell only system. Recovering most of the generated carbon dioxide is major advantage of the system.