• 한국연소학회:학술대회논문집
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• 2002.11a
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• pp.41-47
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• 2002

Oxygen has been used extensively in various industries for many years. Despite earlier successful attempts to use oxygen in industrial combustion furnaces, its full theoretical researches have only recently begun to be realized. The aim of this study is to investigate the effect of oxygen enriched combustion. This paper analyzes the characteristics of oxygen enriched combustion, and deals with the experimental investigation of the flame temperature and NOx concentration in exhaust gas. The flame temperature, concentration of exhaust gas were measured and flame configurations were photographed according to the variation of oxygen concentrations in oxidizer.

• Journal of the Korean Society of Combustion
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• v.11 no.1
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• pp.19-26
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• 2006

Structure of edge flame established in a mixing layer, formed between two uniformly flowing pure $CH_4$ and pure $O_2$ streams, is numerically investigated by employing a detailed methane-oxidation mechanism. The numerical results exhibited the most outstanding distinction of using pure oxygen in the fuel-rich premixed-flame front, through which the carbon-containing compound is found to leak mainly in the form of CO instead of HC compounds, contrary to the rich $CH_4-air$ premixed flames in which $CH_4$ as well as $C_2H_m$ leakage can occur. Moreover, while passing through the rich premixed flame, a major route for CO production, in addition to the direct $CH_4$ decomposition, is found to be $C_2H_m$ compound formation followed by their decomposition into CO. Beyond the rich premixed flame front, CO is further oxidized into $CO_2$ in a broad diffusion-flame-like reaction zone located around moderately fuel-rich side of the stoichiometric mixture by the OH radical from the fuel-lean premixed-flame front. Since the secondary CO production through $C_2H_m$ decomposition has a relatively strong reaction intensity, an additional heat-release branch appears and the resulting heat-release profile can no longer be seen as a tribrachial structure.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.5
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• pp.371-377
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• 2009

In oxy-fuel combustion, $CO_2$ concentration in the flue gas may be enriched up to 95% owing to the gas recirculation. Under the high $CO_2$ concentration, the calcination characteristic of limestone is different from that of the conventional air combustion system. In this study, three types of limestone taken from different regions in Korea were used as $SO_2$ absorbent and their calcination characteristics depending on calcination temperature were investigated. The experiments were performed to examine the effects of operating variables such as absorbent species, reaction temperatures on the $SO_2$ removal efficiency and reacted limestone particles were captured to examine the sulfur contents. The degree of calcination and the specific surface area increased with calcination temperature and $SO_2$ removal efficiency increased with reaction temperature. The results showed remarkable difference in $SO_2$ removal efficiencies between the limestone types. The sulfur content of the reacted limestone with the highest $SO_2$ removal efficiency was about 10%.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.258-262
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• 2011

The laminar burning velocity in premixed Oxy-CH4 flames was studied in a lab-scale Bunsen burner. $CH^*$ chemiluminescence method and Schliren photography were used. Experimental results were compared with numerical prediction which was calculated with a CHEMKIN 3.7 package with a PREMIX code. Global equivalence ratio of oxy-CH4 mixture was varied from 0.5 to 2.0 in a laminar flow region. The laminar burning velocity was measured as 3.1 m/s for Schlieren photograph and 2.9 m/s for $CH^*$ chemiluminescence technique (angle method).

• Journal of Korean Society of Environmental Engineers
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• v.33 no.6
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• pp.420-425
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• 2011

In general, the decomposition of $CaSO_4$ formed by sulfation reaction in the in-furnace desulfurization process using limestone has strong effect on the desulfurization reaction under the oxy-fuel combustion condition. In this study, the conversion rates were measured and reaction rates were calculated in order to investigate the effects of the experimental variables such as temperature and the concentrations of $CO_2$, $O_2$, $SO_2$, on the $CaSO_4$ decomposition reaction using DTF (Drop Tube Furnace) in the desulfurization reaction. The conversion rate and the reaction rate of $CaSO_4$ decomposition reaction were increased with reaction temperature. $CO_2$ concentration has little effect on $CaSO_4$ decomposition reaction in the presence of $O_2$. Under the same experimental conditions, the decomposition rate of $CaSO_4$ was enhanced with the decreasing the $O_2$ concentration, but vice versa with the increasing of $SO_2$ concentration.

• Journal of the Korean Institute of Gas
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• v.23 no.1
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• pp.27-35
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• 2019

In order to solve the global warming and reduce greenhouse gas emissions, $CO_2$ capture technology was developed by applying oxy-fuel combustion. But there has been such a problem that its economic efficiency is low due to the high price of oxygen gases. ASU is known to be most suitable method to produce large quantity of oxygen, to reduce the oxygen production cost, the efficiency of ASU need to be improved. To improve the efficiency of ASU, exergy analysis can be used. The exergy analysis provides the information of used energy in the process, the location and size of exergy destruction. In this study, the exergy analysis was used for process developing and optimization of large scale ASU. The process simulation of ASU was conducted, the results were used to calculate the exergy. As a result, to reduce the exergy loss in the cold box of ASU, a lower operating pressure process was suggested. It was confirmed the importance of heat leak and heat loss reduction of cold box. Also, the unit process of ASU which requires thermal integration was confirmed.

• 한국연소학회:학술대회논문집
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• 2006.04a
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• pp.149-156
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• 2006

Structure of edge flame established in a mixing layer, formed between two uniformly flowing pure $CH_4$ and pure $O_2$ streams, is numerically investigated by employing a detailed methane-oxidation mechanism. The numerical results exhibited the most outstanding distinction of using pure oxygen in the fuel-rich premixed-flame front, through which the carbon-containing compound is found to leak mainly in the form of CO instead of HC compounds, contrary to the rich $CH_4-air$ premixed flames in which $CH_4$ as well as $C_2H_m$ leakage can occur. Moreover, while passing through the rich premixed flame, a major route for CO production, in addition to the direct $CH_4$ decomposition, is found to be $C_2H_m$ compound formation followed by their decomposition into CO. Beyond the rich premixed flame front, CO is further oxidized into $CO_2$ in a broad diffusion-flame-like reaction zone located around moderately fuel-rich side of the stoichiometric mixture by the OH radical from the fuel-lean premixed-flame front. Since the secondary CO production through $C_2H_m$ decomposition has a relatively strong reaction intensity, an additional heat-release branch appears and the resulting heat-release profile can no longer be seen as a tribrachial structure.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2010.04a
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• pp.369-370
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• 2010

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2010.04a
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• pp.610-611
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• 2010

• The KSFM Journal of Fluid Machinery
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• v.12 no.4
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• pp.30-36
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• 2009

Recently, there has been growing interest in the oxyfuel combustion cycle since it enables high-purity $CO_2 capture with high$ efficiency. However, the oxyfuel combustion cycle has some important issues regarding to its performance such as the requirement of water recirculation to decrease a turbine inlet temperature and proper combustion to enhance cycle efficiency. Also, Some of water vapour remain not condensed at condenser outlet because cycle working fluid contains non-condensable gas, i.e., $CO_2$. The purpose of the present study is to analyze performance characteristics of the oxyfuel combustion cycle with different turbine inlet temperatures, combustion pressures and condenser pressure. It is expected that increasing the turbine inlet temperature improves cycle efficiency, on the other hand, the combustion pressure has specific value to display highest cycle efficiency. And increasing condensing pressure improves water vapour condensing rate.