• 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.

• Applied Chemistry for Engineering
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• v.7 no.5
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• pp.999-1005
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• 1996

Pt catalyst on carbon black was prepared by colloidal method, ion exchanging method and methanol reducing method. The colloidal method has been used generally. At ion exchanging method, $H^+$ of functional group on carbon surface made by oxidation treatment was exchanged with Pt ion. At methanol reducing method, Pt was impregnated on carbon to reduce by methanol contained with surfactants. With TEM and XRD, Pt particle size impregnated on carbon by various methods was $30{\sim}50{\AA}$. Loading yield was about 100%, loading yield of ion exchanging method was 99.92% by DCP analysis and 99.87% by combustion method. Within 60 hour, current density of oxygen reduction was $460mA/cm^2$ at 0.7V(vs. RHE) at colloidal method. It was the better performance than catalyst prepared by ion exchanging, methanol reducing method. But, it was shown some decrease of performance for long operation time(after 100hour), catalyst prepared by methanol reducing method was shown stable performance.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.12
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• pp.840-846
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• 2012

Global climate changes caused by $CO_2$ emissions are currently debated around the world; green sources of energy are being sought as alternatives to replace fossil fuels. The sustainable use of biogas for energy production does not contribute to $CO_2$ emission and has therefore a high potential to reduce them. Catalytic steam reforming of a model biogas ($CH_4:CO_2$ = 60%:40%) is investigated to produce $H_2$-rich synthesis gas. The biogas utilized 3D-IR matrix burner in which the surface combustion is applied. The ruthenium catalyst was used inside a reformer. Parametric screening studies were achieved as Steam/Carbon ratio, biogas component ratio, Space velocity and Reformer temperature. When the condition of Steam/Carbon ratio, $CH_4/CO_2$ ratio, Space velocity and Refomer temperature were 3.25, 60% : 40%, $14.7L/g{\cdot}hr$ and $550^{\circ}C$ respectively, the hydrogen concentration and methane conversion rate were showed maximum values. Under the condition mentioned above, $H_2$ yield, $H_2$/CO ratio, CO selectivity and energy efficiency were 0.65, 2.14, 0.59, 51.29%.

• Applied Chemistry for Engineering
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• v.20 no.6
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• pp.653-657
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• 2009

Nitrous oxide is a typical greenhouse gas which is produced from various organic or fossil fuel combustion processes as well as chemicals producing plants. $N_2O$ has a global worming potential of 310 times that of $CO_2$ on per molecule basis, and also acts as an ozone depleting material in the stratosphere. However, its removal is not easy for its chemical stability characteristics. Most SCR processes with several effective reducing agents generally require the operation temperature higher than $450^{\circ}C$, and the catalytic conversion becomes decreased significantly when NOx is present in the stream. Present experiments have been performed to obtain basic design data of actual application concerning the effects of $SO_2$ and $NH_3$ on the interim and long term activities of $N_2O$ reduction with CO over the mixed metal oxide (MMO) catalyst derived from a hydrotalcite-like compound precursor. The MMO catalysts used in the experiments, have shown prominent activities displaying full conversions of $N_2O$ near $200^{\circ}C$ when CO is introduced. The presence of $SO_2$ is considered to show no critical behavior as can be met in the $NH_3$ SCR DeNOx systems and the effect of $NH_3$ is considered to play as mere an impurity to share the active sites of the catalysts.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.7
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• pp.884-891
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• 2016

A secondary injection system in a diesel engine has benefits: it can be controlled independently without interrupting engine control, it can be adapted to various layouts for exhaust systems, and it pose no reductant dilution problems compared to post injection systems in the combustion chamber or other supplemental reductant injections. In a secondary injection system, the efficiency of the catalyst depends on the method of reducing the supply. The reductant needs to be maintained and optimized with constant pressure, the positions and angles of injector is a very important factor. The concentration and amount of reductant can be changed by adjusting secondary injection conditions. However, secondary injection is highly dependent upon the type of injector, injection pressure, atomization, spray technology, etc. Therefore, it is necessary to establish injection conditions the spray characteristics must be well-understood, such as spray penetration, sauter mean diameter, spray angle, injection quantity, etc. Uniform distribution of the reductant corresponding to the maximum NOx reduction in the DeNOx catalyst system must also assured. With this goal in mind, the spray characteristics and impingement plate types of a secondary injector were analyzed using visualization and digital image processing techniques.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.33-36
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• 2014

Gasification of biomass produces syngas containing CO, $H_2$ and/or $CH_4$, which can then be converted into energy or value-added fuels. One of key issues for efficient gasification is to minimize tar concentration in the syngas for use in a final conversion device such as gas engine. This study investigated the decomposition of primary tar by catalytic cracking using char as catalyst, of which the feature can be integrated into a fixed bed gasifier design. The pyrolysis vapor containing tar from pyrolysis of wood at $500^{\circ}C$ was passed through a reactor filled with or without char at $800^{\circ}C$ for a residence time of 1, 3 or 5 sec. Then, the condensable vapor (water and tar) and gases were analyzed for the yields and elemental composition. Four types of char particles with different microscopic surface area and pore size distribution: wood, paddy straw, palm kernel shell and activated carbon. The results were analyzed for the mass and carbon yields of tar and the composition of product gases to conclude the effects of char types and residence time.

• Journal of Environmental Science International
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• v.11 no.6
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• pp.577-582
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• 2002

Selective catalytic reduction and selective non-catalytic reduction processes are mainly used to treat nitrogen oxidants generated from fossil-fuel combustion. Especially, the selective non-catalytic reduction process can be operated more economical and designed more simply than the selective catalytic reduction. For this reason, many researchers carried out to increase the removal efficiency of nitrogen oxidants in the condition of low oxygen concentration by using the selective non-catalytic reduction process. However, this study was flue gas contained high oxygen concentration of 20(v/v%) with ammonia as a reducing agent. Moreover, it carried out experiment with many factors that are reaction temperature, retention time, initial NO concentration, NSR(normalized stoichiometric ratio). It was determined optimal operating conditions to improve NO removal efficiency with SNCR process. The De-NOx efficiency was increased with NSR, initial NO concentration and retention time increasement. This study has NO removal efficiency over 80% in the high oxygen concentration as well as low oxygen concentration. The injection of reducing agent may be considered for SNCR process and facility operation in 850$\^{C}$ of optimal condition.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.5
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• pp.1-6
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• 2009

The temperature of exhaust gas was raised by increasing of engine movement on developing engine. Thermal of high temperature and pressure reverse in bellows, because of increasing of engine movement and the thermal performance of converter in combustion. As a result, thermal loss is increased and thermal efficiency is decreased rapidly in bellows, it can occur to damage in mechanical structure. In this study, it was necessary to analyze back pressure performance and thermal characteristic on driving condition in exhaust system. It was adapted braid type bellows and straight type exhaust pipe. It was compared with curve type exhaust pipe for lay-out on considering to design of exhaust system. It was necessary to improve thermal characteristic and back pressure performance so that expansion cavity pipe(ECP) was installed between bellows and catalyst convert. Not only decreasing back pressure was solved but also thermal characteristic problems in exhaust pipe because of increasing capacity. According to this study, the basis of data is presented when new exhaust system is designed.

• Journal of Oriental Neuropsychiatry
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• v.16 no.2
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• pp.125-133
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• 2005

Object : This paper is designed to inquire into the influence of eating habits on the emotion of modem people. Method : The methodology is used that searches for materials such as books and treatises on the relationship between eating habits and emotion. Result : Meat used for fast food comes from cows that are fed the feed containing growth hormone and antibiotic. Growth hormone extremely supplements fire or yang within the body while antibiotics undermines the process of yin, leading to an accumulation of damp-heat and inflammation of ministerial fire. Additives contained in instant foods also impinge on the process of yin, leading to poor digestion, damp-heat toxins and ministerial fire. Excessive consumption of meat results in incomplete combustion of fat and hinders the formation of essence. Subsequently, ministerial fire becomes hyperactive as a result of the lack of yin energy. Increased meat consumption in the human diet is coupled with unhealthy eating pattern in which people eat too much for dinner and too quickly. Eating too much disturbs digestion, making it slow and incomplete, leading to excess damp-heat conditions, insufficient amount of vital essence and eventually hyperactive ministerial fire. Milk is considered a catalyst of faster growth, making it suitable for calves. Milk intake rapidly increases the balance of yang and eventually cause hyperactivity of ministerial fire. Conclusion : It is estimated that the eating habits of modern people cause the process of yang, making them feel restless, impatient and aggressive.

• Journal of ILASS-Korea
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• v.21 no.2
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• pp.71-77
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• 2016

Air pollutants nitrogen oxides are inevitably generated in the combustion reaction. Its amount trend is steadily increasing because the rapid modern industrialization and population growth. For this reason, NOx is controlled to reducing the harmful components in the exhaust gas. So Marine Environment Protection Committee (MEPC) take effect 'Tier I', 'Tier II' of air pollution regulation in 2005 and 2011 respectively. According to NOx emissions are strictly regulated management of the vessel through them. In addition, since 2016 the regulation enter into force in the next step 'Tier III' was confirmed by MEPC 66th committee. It's 80% enhanced emissions limits than the 'Tier I' Alternatively these emission regulation, research is actively being carried out about exhaust gas after-treatment methods through the vessel application of Selective Catalytic Reduction(SCR). Therefore depending on the basic specification of cell density according to the Area velocity, Space velocity, Linear velocity is studied the effects of NOx removal efficiency