• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.10
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• pp.729-753
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• 2008

Oxy-fuel combustion is a reliable way for the reduction of pollutants, the higher combustion efficiency and the separation of carbon dioxide. The review of recent research trends and the prospects of oxy-fuel combustion were presented. The difference in characteristics among oxy-fuel combustion, conventional air combustion, oxy-fuel combustion with flue gas recirculation (FGR) technique was investigated. Recent experiments of oxy-fuel combustion with/without FGR were surveyed in various ways which are optimized burner design, flame characteristics, the soot emission, the radiation effect, the NOx reduction and the corrosion of combustor. Numerical simulation is more important in oxy-fuel combustion because flame temperature is so high that conventional measurement devices have a restricted application. Equilibrium and non-equilibrium chemical reaction mechanisms for oxy-fuel combustion were investigated. Combustion models suitable for the numerical simulation of non-premixed oxy-fuel flame were surveyed.

• 한국연소학회:학술대회논문집
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• 2012.04a
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• pp.337-339
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• 2012

This study investigates the combustion and heat transfer characteristics of a 100MWe pulverized coal boiler retrofitted for demonstration of oxy-coal combustion. By computational fluid dynamics (CFD), the flame temperature and wall heat flux were compared for air-fuel and oxy-fuel combustion with different $O_2$ concentration in the oxidizers. It was found that the oxy-fuel combustion requires an $O_2$ concentration higher than 27 vol.% for the boiler to achieve the similar value of wall heat flux with air-fuel combustion.

• 한국연소학회:학술대회논문집
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• 2004.11a
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• pp.175-180
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• 2004

Improving furnace efficiency is a high priority need for aluminum, glass, steel and other metal casting industries. Oxy-fuel combustion is considered to be one of the most effective method to improve thermal efficiency and reduce $NO_x$, SOx and $CO_2$ emissions for high temperature furnaces. The characteristics of an oxy-fuel flame, in particular its shape, radiation profile and exhaust gas composition are considerably different to those of an air-fuel burner. For this reason, a new approach is needed regarding factors such as burner design, power input levels, number and positioning strategies of burners and also control philosophies. In this paper will discuss the latest developments of high performance oxy-fuel combustion reheating furnace system. This high performance oxy-fuel combustion system will be shown to be technologically superior to other types of combustion systems in the areas of fuel efficiency, emissions and productivity.

• Journal of the Korean Society of Combustion
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• v.13 no.1
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• pp.31-43
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• 2008

Oxy-fuel flame has a significantly different structure from that of air-fuel flame because of its high temperature. This study is aimed to find out the difference of the oxy-fuel flame structure in order to understand reaction mechanism closely, which is crucial to design real-scale oxy-fuel combustion system. By examining pictures of counterflow flame and LIF images, we found that oxy-fuel flame had two-zone structure: fuel decomposition region and distributed CO oxidation region. In the oxy-fuel flame, OH radical was distributed intensely through the whole flame due to its higher flame temperature than crossover temperature. For showing those features of the oxy-fuel flame, 1 MW scale IFRF oxy-natural gas burner was simulated by conditional moment closure(CMC) model. Calculation results were compared with experimental data, and showed agreements in trend. In the simulated distributions of fuel decomposition/CO oxidation rates, CO oxidation region was also separated from fuel decomposition zone considerably, which showed the two-zone structure in the oxy-fuel flame.

• Journal of the Korean Society of Combustion
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• v.16 no.1
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• pp.22-29
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• 2011

This paper focuses on the combustion characteristics of blended coals with bituminous and sub-bituminous coals under air and oxy-fuel combustion conditions. The effects of oxygen concentration and blending ratio on the combustion characteristics were experimentally investigated using a thermogravimetric analyser (TGA). Characteristic temperatures including ignition, burnout temperature and activation energy were determined from TG and DTG combustion profiles. As oxygen concentration increased and the presence of sub-bituminous coal, characteristic temperatures and activation energy decreased. The ignitability, reactivity and kinetics have all been greatly improved under oxy-fuel combustion conditions. Based on this, co-firing with bituminous and sub-bituminous coals under oxy-fuel combustion conditions may be suggested as an alternative method to the fuel flexibility and cost-effective power production with carbon capture and sequestration.

• 한국연소학회:학술대회논문집
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• 2006.10a
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• pp.229-234
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• 2006

The oxy-fuel combustion heating characteristics is investigated experimentally by measuring furnace and steel temperature variations for batch type furnace simulator with a specially designed low NOx oxy-fuel burner. Economics of using oxy-fuel combustion is confirmed and, the furnace and steel temperature variations for different heating conditions are compared to deduce optimal heating control pattern for energy savings and rapid uniform heating. High $CO_2$ concentration (> 80-90%), low NOx (< 40ppm) and CO (< 10ppm) are measured in the flue gas. Temperature differences (< $30^{circ}C$) inside the furnace and steel are reduced relatively by increasing the burner jet momentum.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2175-2180
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• 2008

Oxy-fuel combustion has been gaining its significance as a means of migrating the green house effects. Some experimental measurements were conducted to investigate the characteristics of oxy-fuel combustion and to aid a fundamental design of a lab-scale oxy-fuel combustor with a coaxial burner. CO emission was measured along the combustor centerline while combustion of methane and oxygen diluted by CO2 took place. Substitution of CO2 with N2 indicates a possibility that some CO is formed by dissociation of CO2. Some parametric tests were also performed to see the mixing effects of reactant gases on CO emission by changing the gas injection velocity at the burner nozzles with various heat loads. The overall results indicate that CO emission was reduced when the reactants are injected at higher velocities of similar magnitude.

• 한국연소학회:학술대회논문집
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• 2013.06a
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• pp.121-122
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• 2013

In recent years, the usage of fossil fuels has caused problems of climate change and global warming. Because the combustion of fossil fuels is related to the production of greenhouse gases ($CO_2$, $CH_4$, etc.), new technology in the field of combustion is needed in order to handle the crisis of climate change and the global warming. As one of the efforts to reduce the emission of greenhouse gases, the concept of regenerative oxy-fuel combustion for energy efficiency and carbon capture was suggested, In the current study, the development of an industrial regenerative oxy-fuel combustion furnace was introduced, which has been being performed at Korea Institute of Energy Research (KIER).

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.51-54
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• 2008

This study aims to devise and analyze a power generation system combining the solid oxide fuel cell and oxy-fuel combustion technology. The fuel cell operates at an elevated pressure, a constituting a SOFC/gas turbine hybrid system. Oxygen is extracted from the high pressure cathode exit gas using ion transport membrane technology and supplied to the oxy-fuel power system. The entire system generates much more power than the fuel cell only system due to increased fuel cell voltage and power addition from oxy-fuel system. More than one third of the power comes out of the oxy-fuel system. The system efficiency is also higher than that of the fuel cell only system. Recovering most of the generated carbon dioxide is major advantage of the system.

• Korean Chemical Engineering Research
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• v.55 no.6
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• pp.846-853
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• 2017

Cold bed and $30kW_{th}$ pilot bed tests using circulating fluidized bed (CFB) were conducted to apply oxy-fuel technology for waste sludge combustion as a carbon capture and storage technology. In cold bed test, the minimum fluidization velocity ($u_{mf}$) and superficial velocity for fast fluidization was determined as 0.120 m/s and 2.5 m/s, respectively. In the pilot test, air and oxy-fuel combustion experiments for waste sludge were conducted using CFB unit. The flue-gas temperature in 21~25% oxy-fuel combustion was higher than that of air and up to 30% oxy-fuel combustion. In addition, the concentration of carbon dioxide was more than 80% with the oxygen injection range from 21% to 25% in oxy-fuel CFB waste sludge combustion.