• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.58-61
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• 2009

The characteristics of nitrous oxide catalytic decomposition were studied to utilize the nitrous oxide as a propellant. The Ru and Pt were selected as nitrous oxide decomposition catalysts and loaded in the $Al_2O_3$ support using an impregnation method. The nitrous oxide conversions as a variation of GHSV and reaction temperature were measured in a tubular reactor. At the low GHSV and high temperature, the conversion was increased, and Ru/$Al_2O_3$ catalyst showed better performance than Pt/$Al_2O_3$ catalyst.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.269-272
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• 2009

Catalytic decomposition of nitrous oxide was investigated experimentally. Two noble metal catalyst (Pt, Ir) were chosen to decompose nitrous oxide. Each catalyst was tested with different chamber pressure and preheating temperature. Ir decomposed $N_2O$ at lower temperature ($230^{\circ}C$) and suitable for $N_2O$ decomposition. In addition, the minimum required preheating temperature decreased as the chamber pressure increased. However, deactivation of Ir catalyst was observed during the experiments.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.4
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• pp.369-375
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• 2010

The study on the characteristics of nitrous oxide catalytic decomposition was carried out to utilize the nitrous oxide as a propellant. The Pt, Ir and Ru were synthesized to select a high performance catalyst for the nitrous oxide decomposition reaction. The respective catalyst precursors were loaded in the $Al_2O_3$ support using an wet impregnation method. The $N_2O$ conversion as a variation of space velocity and reaction temperature was measured using a tubular reactor. The catalyst loss was measured to evaluate the durability of catalysts after the reaction at $800^{\circ}C$ for 2 hours. The $N_2O$ conversion was increased at the decrease of space velocity and at the increase of temperature. The Ru/$Al_2O_3$ catalyst had the highest $N_2O$ conversion at low temperature and the best durability.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.2
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• pp.46-54
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• 2015

Nitrous oxide is known as green and safe propellant, and can be supplied by its own vapor pressure. So, many liquid propulsion research institutes and university laboratories use nitrous oxide as oxidizer of experimental liquid rocket engine. However, the unknown explosions occurred twice during hot fire experiments using subscale ethanol/nitrous oxide thruster. In this paper, we surmised that the explosions were caused by the decomposition of nitrous oxide in the injector body and the recondensation of nitrous oxide. Improvement and the safe handling methods are suggested.

• Applied Chemistry for Engineering
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• v.19 no.6
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• pp.624-628
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• 2008

Nitrous oxide ($N_2O$), known as one of the major greenhouse gases, is an important component of the earth's atmosphere, and gives rise to precursor of acid rain and photochemical smog. For the removal of $N_2O$ and other nitrogen oxides, the SCR reaction system with various reductants is widely used. This study is based on the results of experimental and theoretical examinations on the catalytic decomposition of sole nitrous oxide ($N_2O$) and selective catalytic reduction of $N_2O$ with $CH_4$ in the presence of oxygen using mixed metal oxide catalysts obtained from hydrolatcite-type precursors. When $CH_4$ is fed together with a reductant, it affects positively on the $N_2O$ decomposition activity. At an optimum ratio of $CH_4$ to $O_2$ mole ratio, the $N_2O$ conversion activity is enhanced on the SCR reaction with partial oxidation of methane.

• Clean Technology
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• v.15 no.2
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• pp.122-129
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• 2009

The effect of calcination temperature or hydrothermal treatment of commercial Fe-beta zeolites in the range of $450{\sim}900^{\circ}C$ were examined in the direct decomposition of $N_2O$. Fe-beta zeolites used were characterized using XRD, $N_2$ sorption, $^{27}Al$ MAS NMR and XPS. Although the surface area and micropore volume of Fe-beta zeolite after calcination at $900^{\circ}C$ and hydrothermal treatment at $750^{\circ}C$ decreased ca. 30%, a larger decrease in the surface area and micropore volume by hydrothermal treatment was observed than by calcination treatment alone. However, the Al sites in frameworks of zeolite were conserved in stable tetrahedral form resulting from low degree of dealumination which was related to the adjacent Fe ions on the Al sites. This could likely be correlated with the conservation of high surface area and micropore volume of Fe-beta zeolites. The increase in the calcination or hydrothermal treatment temperature caused the increase of decomposition temperature of $N_2O$ and the severe deactivation was observed after hydrothermal treatment than calcination treatment.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.202-205
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• 2010

Auto ignition of hybrid rocket using $N_2O$ catalytic decomposition was studied in the present study. The hybrid rocket consists of catalytic igniter, solid fuel, combustor, and nozzle. The Ru/$Al_2O_3$ catalyst for $N_2O$ decomposition was synthesized by an impregnation method, and $N_2O$ conversion as reaction temperatures was measured. The temperature change of the catalytic ignitor was measured at the operating condition, and the possibility for the auto ignition of hybrid rocket was validated.

• Applied Chemistry for Engineering
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• v.19 no.1
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• pp.17-26
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• 2008

With the effectuation of Kyoto Protocol on the United Nations Framework Convention on the Climate Change, the emission reduction of greenhouse gases became an urgent issue and has been competitively secured among countries as the form of certificates through clean development mechanism (CDM) or joint implementation (JI). Nitrous oxide ($N_2O$) is one of the major greenhouse gases along with carbon dioxide ($CO_2$) and methane ($CH_4$) having warming potential 310 times that of carbon dioxide and chemically very stable in the atmosphere to give a life time of more than 120 years so that it reaches to the stratosphere to act as an ozone depleting substance. $N_2O$ hardly decomposes and thus, besides to the adoption of thermal decomposition at high temperature, selective catalytic reduction methods are usually used at temperatures over $400^{\circ}C$ in which the presence of NOx acts as a major impeding material in the decomposition process. In this article, the sources of various $N_2O$ generation, catalytic reduction processes and the status and trends of emission trade with CDM projects for greenhouse gas reduction are summarized and discussed on a condensed basis.

• Journal of ILASS-Korea
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• v.25 no.3
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• pp.132-138
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• 2020

N₂O is hazardous atmosphere pollution matter which can damage the ozone layer and cause green house effect. There are many other nitrogen oxide emission control but N₂O has no its particular method. Preventing further environmental pollution and global warming, it is essential to control N₂O emission from industrial machines. In this study, the thermal decomposition experiment of N₂O gas mixture is conducted by using cylindrical reactor to figure out N₂O reduction and NO formation. And CHEMKIN calculation is conducted to figure out reaction rate and mechanism. Residence time of the N₂O gas in the reactor is set as experimental variable to imitate real SNCR system. As a result, most of the nitrogen components are converted into N2. Reaction rate of the N₂O gas decreases with N₂O emitted concentration. At 800℃ and 900℃, N₂O reduction variance and NO concentration are increased with residence time and temperature. However, at 1000℃, N₂O reduction variance and NO concentration are deceased in 40s due to forward reaction rate diminished and reverse reaction rate appeared.

• Korean Chemical Engineering Research
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• v.40 no.6
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• pp.746-751
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• 2002

Fluidized bed combustion is a coal combustion technology that can reduce both SOx and NOx emission; SOx is removed by limestone that is fed into the combustion chamber and the NOx is reduced by low temperature combustion in a fluidized bed combustor and air stepping, but $N_2O$ generation is quite high. $N_2O$ is not only a greenhouse gas but also an agent of ozone destruction in the stratosphere. The calcium oxide(CaO) is known to be a catalyst of $N_2O$ decomposition. This study of $N_2O$ decomposition reaction in fixed bed reactor packed over CaO bed has been conducted. Effects of parameters such as concentration of inlet $N_2O$ gas, reaction temperature, CaO bed height and effect of $CO_2$, NO, $O_2$ gas on the decomposition reaction have been investigated. As a result of the experiment, it has been shown that $N_2O$ decomposition reaction increased with the increasing fixed bed temperature. While conversion of the reaction was decreased with increasing $CO_2$ concentration. Also, under the present of NO, the conversion of $N_2O$ decomposition is decreased. From the result of kinetic study gained the heterogeneous reaction rate on $N_2O$ decomposition. In the case of $N_2O$ decomposition over CaO, heterogeneous reaction rate is. $\frac{d[N_2O]}{dt}=\frac{3.86{\times}10^9{\exp}(-15841/R)K_{N_2O}[N_2O]}{(1+K_{N_2O}[N_2O]+K_{CO_2}[CO_2])}$. In this study, it is found that the calcium oxide is a good catalyst of $N_2O$ decomposition.