• Transactions of the Korean hydrogen and new energy society
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• v.27 no.5
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• pp.562-570
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• 2016

At the carbon dioxide capture process using the aqueous amine solution, degradation of absorbents is main factor to reducing the process performance. Also, degradation mechanism of absorbent is important for understanding the environmental risk, route of degradation products, health risk etc. In this study, the degradation products of MEA were studied to clarify mechanism in thermal degradation process. The degradation products were analyzed using a $^1H$ NMR (nuclear magnetic resonance) and $^{13}C$ NMR. The analysis methods used in this study provide guidelines that could be used to develop a degradation inhibitor of absorbent and a corrosion inhibitor.

• Journal of Sensor Science and Technology
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• v.18 no.3
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• pp.202-206
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• 2009

Flat type catalytic combustible hydrogen sensors were fabricated using platinum micro-heaters and sensing material pastes. The platinum micro-heater was formed on an alumina substrate by sputtering method. The paste for the sensing materials was prepared using ${\gamma}-Al_2O_3$ 30 wt%, $SnO_2$ 35 wt%, and Pd/Pt 30 wt% and coated on the platinum micro-heater. The sensing performances were tested for the prepared sensors with different substrate sizes. The micro catalytic combustible hydrogen sensors showed quick response time, high reliability, and good selectivity against various gases(CO, $C_3H_8,\;CH_4$) at low operating temperature of $156^{\circ}\C$.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.47-52
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• 2004

In the design of scramjet intake for hypersonic flight, a variety of aerothermodynamics phenomena are encountered. These phenomena include blunt leading - edge effects, boundary layer development issues, transition, inviscid / viscous coupling, shock - shock interactions, shock / boundary - layer interactions, and flow profile effects. For intakes that are designed to operate within a narrow Mach number / altitude envelope, an understanding of a few of these phenomena might be required. In this work several predominant flowfield phenomena (viscous phenomena, boundary - layer separation, and combustor entrance profile) are discussed to investigate the performance of the intake at the altitude and angle of attack extremes of the HyShot flight experiment.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.42-45
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• 2012

As a basic research for the development of Korean lunar lander, propulsion system development for ground test is in progress. Design target is 220 N in ground thrust at 130 g/s flow rate, 200 psi chamber pressure. For the performance improvement, two type injector and catalyst bed was designed. For ground test, thrust measurement system using LM guide was developed and test was performed. The result shows 214.1 N thrust in atmosphere condition at 126.6 g/s flow rate.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.424-428
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• 2012

Air-breathing Propulsion System is one of the promising propulsion systems because of low cost, easy storage, compactness and simplicity. A study of gas generator propellant for air-breathing propulsion system was performed in this paper. Amorphous Boron Powder was applied in propellant with various kinds of additives to determine combustion characteristics. And boron beads were made to apply them to the propellant. Combustion characteristics of propellant using amorphous boron powder and boron beads was compared.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.6
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• pp.45-52
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• 2020

In this paper, a subminiature solid rocket motor(SSRM) was designed to develop a miniature smart-bullet and the designed propellant grain was made of thermoplastic propellant for production convenience of inner shape. The internal ballistics analysis and ground test were performed to investigate the performance of SSRM. And a numerical simulation was carried out to obtain basic data on the design of safety distance between the nozzle outlet and a gunner, the temperature distribution of exhaust gas was analyzed by comparing a numerical simulation and the results of IR camera.

• Journal of The Korean Association For Science Education
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• v.28 no.6
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• pp.633-640
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• 2008

In this study, we investigated the possibility of using science laboratory reports in identifying students' ideas about discrepant events. A specially designed science laboratory report was developed in this study, and used to collect the information about students' responses toward discrepant events. A total of 839 laboratory reports on the solubility of gas, combustion, and the electrical conductivity of a solution were analyzed. Students' responses in the laboratory reports were classified into eight types; rejection, reinterpretation, exclusion, uncertainty, peripheral theory change, theory change, maintenance of scientific conception, and regressive theory change. In addition, reinterpretation and theory change were further classified into several subcategories. The characteristics of students' responses in this study were discussed in comparison with those of previous studies.

• Clean Technology
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• v.27 no.4
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• pp.350-358
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• 2021

The results of this study shows that the combustor temperature ranged from 848.27 to 1,026.80 ℃, averaging about 976.61 ℃, and the NOx concentration increased as the temperature increased. The urea usage ranged from 291.00 to 693.00 kg d^-1, averaging about 542.34 kg d^-1, and the NOx concentration decreased as the urea usage increased. Residence time was about 3.38 to 9.17 s, averaging about 5.22 s, about 2.61 times larger than the 2 s of the design details. This is 1,086 kg h^-1, averaging about 55.71%, compared to the 1,950 kg h^-1 SRF input permission standard. The combustion chamber area is constant, but the residence time is shown to increase with the decrease of exhaust gas. The O₂/CO ratio was 847.05 to 14,877.34, averaging about 3,111.30, and the NOx concentration slightly increased as the O₂/CO ratio increased. As the combustor temperature and O₂/CO ratio increased, the combustion reaction with nitrogen in the air increased and the NOx concentration slightly increased. As the urea usage and residence time increased, the NOx concentration decreased slightly with an increase in reactivity with NOx. The NOx concentration at the stack ranged from 7.88 to 34.02 ppm with an average of 19.92 ppm, and was discharged within the 60 ppm emission limit value. The NOhx emission factor was 1.058 to 1.795 kg ton^-1, averaging about 1.450 kg ton^-1. This value was about 24.87% of the maximum emission factor of 5.830 kg ton^-1 of other solid fuels. Other synthetic resins and industrial wastes were 79.80% and 43.65% compared to 1.817 kg ton^-1 and 3.322 kg ton^-1, respectively. This value was similar to 1.400 kg ton^-1 of RDF in the NIER notice (2005-9), 10.98% compared to the maximum SRF of 13.210 kg ton^-1. Therefore, the NOx emission factor had a large deviation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.6
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• pp.584-590
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• 2012

In this study, we have conducted a work on homogenizer development which is operated by high shearing force generated by stator and rotor inside it. To investigate the performance for homogenization and atomization of homogenizer, Bunker-C (IFO 380 cSt) was used as a fuel for experiment. Pre-treatment of bunker-C was carried out with homogenizer developed in this study. Oil purifier was used to investigate effect of oil sludge reduction after pre-treatment. Experimental result showed that the amount of sludge of fuel oil after pre-treatment with homogenizer has decreased by 13 %. To confirm combustion efficiency, Bunker-C which have pre-treatment with homogenizer and purified after are burned in boiler system. The result showed that CO concentration in exhaust gas was decreased. These results mean that if the homogenizer which is developed in this study for marine fuel oil is applied on real vessels, oil costs and operating costs can be reduced.

• Clean Technology
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• v.7 no.1
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• pp.51-63
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• 2001

In this study, PSA, known as the most economic process, was used to recover $CO_2$ from the power-plant flue gas. Activated carbon and zeolite molecular sieve 13X were used as adsorbent. Activated carbon has been deemed inadequated adsorbent for separating $CO_2$ from the flue gas. However, highly concentrated $CO_2$ could be obtained as a product on the activated carbon adsorbent using the new operating cycle modifying the rinse step. Also, the recovery of $CO_2$ was improved using double-layered adsorption column packed with the activated carbon and the zeolite 13X simultaneously. Adsorption column was filled with the activated carbon in the feed-end side, and the zeolite 13X in the product-end side. The recovery of $CO_2$ increased about 40% with only 25% zeolite, and increased 67% with 50% zeolite at the experimental conditions of 13% $CO_2$ concentration, 10 SLPM flow rate and 2.2 atm adsorption pressure.