• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.602-605
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• 2008

$CO_2$ 분리는 크게 연소전 탈탄소화(pre-combustion capture)와 연소후 포획(post-combustion capture)으로 나누어지는데, post-combustion capture는 연료가 연소하면 $N_2$와 $CO_2$가 남게 되고 흡수나, 흡착, 막분리 등을 이용해서 $CO_2$를 분리하는 것이고, Pre-combustion capture(연소전 회수)는 연소 전에 이산화탄소가 발생되지 않도록 하는 기술로써, 부분 산화나 개질 및 수성가스 변위반응 등이 포함되며 생성된 수소와 이산화탄소를 분리하여 수소를 생산하는 기술($CO_2/H_2$ 분리가 핵심)이다. 우리나라는 대부분 연소 후 포획 위주로 많은 연구가 진행되어 왔지만, 최근 고유가 시장이 형성되면서 석탄화력발전 및 복합가스발전(IGCC)에 필요한 연소전 탈탄소화($H_2/CO_2$ 가스로부터 $CO_2$ 회수) 연구에 산업적 관심이 급상승 되고 있다. 특히, Pre-combustion 과정에서는 높은 자체압력(약 2.5 - 5.0MPa)과 비교적 높은 농도의 $CO_2$(약 40%의)가 발생되기 때문에, 연소전 탈탄소화는 가스하이드레이트 형성/분해 원리가 가장 잘 적용될 수 있는 기술이라 할 수 있다. 본 연구에서는 비교적 저압 조건에서도 하이드레이트를 보다 쉽게 형성시키는 촉진제를 이용하여 $CO_2/H_2$ 혼합 가스 중 $CO_2$를 분리하는 실험을 수행하였다.

• Journal of Mechanical Science and Technology
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• v.16 no.9
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• pp.1112-1120
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• 2002

Numerical investigations on air staging and fuel staging were carried out with a newly designed coaxial cyclone combustor, which uses the method of two stage coal combustion composed of pre-combustor and main combustor. The pre-combustor with a high air/fuel ratio is designed to supply gas at high temperature to the main combustor. To avoid local high temperature region in this process, secondary air is injected in the downstream. Together with the burned gas supplied from the pre-combustor and the preheated air directly injected into main combustor, coals supplied through the main burner react rapidly at a low air/fuel ratio. Strong swirling motion of cyclone combustor keeps the wall temperature high, which makes slagging combustion possible. Alaska, US coal is used for calculations. Predictions were made for various coal flow rates in the main combustor for fuel staging and for the various flow rate of secondary air in the pre-combustor for air staging. In-scattering angles are also chosen as a variable to increase residence times of coal particles. Temperature fields and particle trajectories for various conditions are described. Predicted temperature variations at the wall of the combustor are compared with corresponding experimental data and show a similar trend. The in-scattering angle of 20° is recommended to increase the combustion efficiency in the main chamber.

• 한국연소학회:학술대회논문집
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• 2001.06a
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• pp.187-192
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• 2001

A homogeneous premixed charge compression ignition engine is experimentally investigated for the reduction of exhaust emissions in diesel engines. In this study, the premixed fuel is injected into the intake manifold to form homogeneous pre-mixture in the combustion chamber and then this pre-mixture is ignited by small amount of diesel fuel directly injected into the cylinder. In the premixed charge compression ignition engine, NOx and smoke concentration of the exhaust emissions were reduced simultaneously as compared with the conventional diesel engine. But HC and CO emissions were increased with the increase of premixed ratio. The combustion characteristics of premixed charged diesel engine such as the power output, the rate of heat release, and the other characteristics are discussed.

• Journal of Power System Engineering
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• v.18 no.6
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• pp.113-119
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• 2014

Due to the development of the petroleum refining technology and continuously increased demand from markets, a quantity of gasoline and diesel oil produced from a restricted quantity of crude oil has been increasing, and residual fuel to be used at marine diesel engines has been gradually becoming low quality. As a result, it was recently reported that trouble oils which cause abnormal combustion such as knocking with extreme noise and misfire from internal combustion engines were increasing throughout the world. In this study, an author investigated ignitability and combustion quality by using combustion analyzer with constant volume(FCA, Fuel Combustion Analyzer) and middle speed diesel engine about MDO(Marine Diesel Oil), HFO(Heavy Fuel Oil), LCO(Light Cycle Oil) and Blend-HFO which was blended LCO of 1000 liters with HFO of 600 liters. Moreover, for betterment of ignitability and combustion quality of injected fuels, multi-injection experiment was carried out in the diesel engine using Blend-HFO. According to the results of FCA analysis, ignitability and combustion quality was bad in the order of MDO

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.35.1-35.1
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• 2005

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.5
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• pp.343-348
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• 2009

The present study has experimentally investigated the effects of $CO_2$ diluted oxygen on the structure of swirl-stabilized flame in a lab-scale combustor. The methane fuel and oxidant mixture gas ($CO_2$ and $O_2$) were mixed in a pre-mixer and introduced to the combustor through different degrees of swirl vanes. The flame characteristics were examined for various amount of carbon dioxide addition to the methane fuel and various swirl strengths. The effects of carbon dioxide addition and swirl intensity on the combustion characteristics of pre-mixed methane flames were examined using chemiluminescence techniques to provide information about flow field. The results show that the hot combustion zone increases at the upstream reaction zone because of an increase in the recirculation flow for an increase in swirl intensity. The hot combustion zone is also increased at the downstream zone by recirculation flow because of an increase in swirl intensity which results in higher centrifugal force. The OH and CH radical intensities of reaction zone decrease with carbon dioxide addition because the carbon dioxide plays a role of diluted gas in the reaction zone.

• International Journal of Automotive Technology
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• v.7 no.1
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• pp.17-23
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• 2006

An experimental study was carried out to obtain the fundamental data about the effect of sub-chamber on pre-mixture combustion. A eve (constant volume combustor) divided into a sub-chamber and a main chamber was used in this experiment. The volume of the sub-chamber was varid trom $0.45\%$ to $1.4\%$ about the whole combustion chamber. The sub-chamber has twelve narrow radial passage holes and a spark plug to ignite the pre-mixture. As the ignition occurs in the sub-chamber by a spark discharge, burned and unburned gas including a great number of radicals is injected into the main chamber, then the multi-point ignition occurs in the main chamber. The combustion pressure is measured to calculate the burning velocity mainly as a function of the sub-chamber volume, the diameter of the passage holes, and the equivalence ratio. In the case of RI (radical ignition) methods, the overall burning time became very short and the maximum burning pressure was slightly increased as compared with that of SI (spark ignition) method. The optimum design value of the sub-chamber is near 0.11 $cm^{-l}$ in the ratio of total area of holes to the sub-chamber volume.

• Journal of the Korean Society of Visualization
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• v.14 no.3
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• pp.51-58
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• 2016

New concept spark plug was developed to study its influence on the combustion characteristics of SI engine. It has pre-ignition chamber at the lower end of spark plug and flame hole, in which fresh mixture gas can be put in through the flame hole without any fuel supply system. This spark plug was tested in a single cylinder engine dynamometer for different air fuel ratio to measure the fuel consumption rate, emission gases, and MBT timing. And constant volume combustion chamber was made to understand flame characteristics of spark plug. New spark plug induced fast burn compared to the conventional spark plug and its effects were increased in lean air fuel ratio. Pre-ignition chamber spark plug with 5 holes which had adjusted size was more stable and effective in combustion performance than pre-ignition chamber spark plug with 1 hole. And its effects showed larger differences in lean air fuel ratio than stoichiometric condition. Flame kernel and flame growth process of conventional spark plug and pre-ignition chamber spark plug studied by flame visualization of schlieren method.

• Tribology and Lubricants
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• v.37 no.2
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• pp.62-70
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• 2021

The problem with intermetallics coating using the heat of molten casting is that the heat generated during combustion synthesis dissolves the coating and the substrate metal. This study investigates whether pre-annealing before synthesis can control the reaction heat, with the aim of Ni₃Al coating on the casting surface. Therefore, the effects of the annealing temperature and time on the combustion synthesis behavior of the powder compact of Ni-25at%Al after annealing were investigated. As results, the reaction heat when synthesized decreased as the annealing temperature was high and the annealing time was longer. This was attributed to the fact that Al was diffused to Ni particles during low temperature annealing and intermediate Ni-Al compounds were formed during high temperature annealing. After combustion synthesis, however, it was found that their microstructures were almost identical except for the amount of intermediate intermetallics. Furthermore, an annealing temperature above 450℃, at which intermediate compounds begin to form, is needed to prevent the dissolving problem during synthesizing. The intermetallics synthesized after annealing at higher temperature and prolonger annealing time showed a good wear resistance. This might be because much intermediate intermetallics of high hardness were remained in the microstructure.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.2
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• pp.9-14
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• 2002

A homogeneous premixed charge compression ignition engine has been experimentally studied far the reduction exhaust emissions of diesel engines. In this study, the gasoline fuel is injected into the intake manifold to from homogeneous pre-mixture in the combustion chamber and then this pre-mixture is ignited by small amount of diesel fuel directly injected into the cylinder. In the premixed charge compression ignition engine, NOx and smoke concentration of the exhaust emissions were reduced simultaneously as compared with the conventional diesel engine. The combustion characteristics of premixed charged diesel engine such as the power output, the rate of heat release, and the other characteristics are discussed.