NO x and SO 2 emissions from O 2 /CO 2 recycle coal combustion

Croiset, Eric; Thambimuthu, K V

doi:10.1016/s0016-2361(00)00197-6

Cited by 275 publications

(140 citation statements)

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“…Indeed, small amounts of N 2 can lead to significant NO x emissions due to the high-temperature characteristic of oxy-fuel flames and the induced predominance of the thermal mechanism. However, if CO 2 dilution is considered, flame temperatures can be significantly reduced and NO x emissions are expected to be lower than in air-diluted conditions [7].…”

Section: Introductionmentioning

confidence: 99%

On the structure of the near field of oxy-fuel jet flames using Raman/Rayleigh laser diagnostics

Sevault

Dunn

Ditaranto

2012

Combustion and Flame

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An experimental study on turbulent non-premixed jet flames is presented with focus on CO 2 -diluted oxy-fuel combustion using a coflow burner. Measurements of local temperatures and concentrations of the main species CO 2 , O 2 , CO, N 2 , CH 4 , H 2 O and H 2 were achieved using the simultaneous line-imaged Raman/Rayleigh laser diagnostics setup at Sandia National Laboratories. Two series of flames burning mixtures of methane and hydrogen were investigated. In the first series, the hydrogen molar fraction in the fuel was varied from 37 to 55 %, with a constant jet exit Reynolds number Re Fuel of 15,000. In the second series the jet exit Reynolds number was varied from 12,000 to 18,000, while keeping 55 % H 2 molar fraction in the fuel. Besides local temperatures and concentrations, the results revealed insights on the behaviour of localized extinction in the near-field. It was observed that the degree of extinction increased as the hydrogen content in fuel was decreased and as the jet Reynolds number was increased. Based on the distribution of the temperature, a fully burning probability index able to quantify the degree of extinction along the streamwise coordinate was defined and applied to the present flame measurements. A comparison of measured conditional mean of mass fractions and laminar flame calculations underlined the significant level of differential diffusion in the near-field that tended to decrease farther downstream. The results also showed high local CO levels induced by the high content of CO 2 in the oxidizer and flame products. A shift of maximum flame temperature was observed toward the rich side of the mixture fraction space, most likely as a consequence of reduced heat release in the presence of product dissociation. Main characteristics of laser Raman scattering measurements in CO 2 -diluted oxy-fuel conditions compared to air-diluted conditions are also highlighted. Most data, including scalar fluctuations and conditional statistics are available upon request.

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Section: Introductionmentioning

confidence: 99%

On the structure of the near field of oxy-fuel jet flames using Raman/Rayleigh laser diagnostics

Sevault

Dunn

Ditaranto

2012

Combustion and Flame

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“…However, there have been contradictory observations on SO 2 emissions under oxy firing and air firing. Some researchers (Kiga et al 1997, Croiset et al 2001, Yamada 2007, D.M. Woycenko 1995, Hu et al 2000, Wall et al 2009) have indicated that SO 2 emissions under oxy firing decreased as compared to air firing.…”

Section: Subtask 34 -Oxy-coal Combustion In Circulating Fluidized Bedsmentioning

confidence: 99%

Oxy-coal Combustion Studies

Wendt

Eddings

Lighty

et al. 2012

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The objective of this project is to move toward the development of a predictive capability with quantified uncertainty bounds for pilot-scale, single-burner, oxy-coal operation. This validation research brings together multi-scale experimental measurements and computer simulations. The combination of simulation development and validation experiments is designed to lead to predictive tools for the performance of existing air fired pulverized coal boilers that have been retrofitted to various oxy-firing configurations. In addition, this report also describes novel research results related to oxy-combustion in circulating fluidized beds. For pulverized coal combustion configurations, particular attention is focused on the effect of oxy-firing on ignition and coal-flame stability, and on the subsequent partitioning mechanisms of the ash aerosol. To these ends, the project has focused on the following:• The development of reliable Large Eddy Simulations (LES) of oxy-coal flames using the Direct Quadrature Method of Moments (DQMOM) (Subtask 3.1). The simulations were validated for both non-reacting particle-laden jets and oxy-coal flames.• The modifications of an existing oxy-coal combustor to allow operation with high levels of input oxygen to enable in-situ laser diagnostic measurements as well as the development of strategies for directed oxygen injection (Subtask 3.2). Flame stability was quantified for various burner configurations. One configuration that was explored was to inject all the oxygen as a pure gas within an annular oxygen lance, with burner aerodynamics controlling the subsequent mixing.• The development of Particle Image Velocimetry (PIV) for identification of velocity fields in turbulent oxy-coal flames in order to provide high-fidelity data for the validation of oxy-coal simulation models (Subtask 3.3). Initial efforts utilized a laboratory diffusion flame, first using gas-fuel and later a pulverized-coal flame to ensure the methodology was properly implemented and that all necessary data and image-processing techniques were fully developed. Success at this stage of development led to application of the diagnostics in a large-scale oxy-fuel combustor (OFC).• The impact of oxy-coal-fired vs. air-fired environments on SO x (SO 2 , SO 3 ) emissions during coal combustion in a pilot-scale circulating fluidized-bed (CFB) (Subtask 3.4). Profiles of species concentration and temperature were obtained for both conditions, and profiles of temperature over a wide range of O 2 concentration were studied for oxy-firing conditions. The effect of limestone addition on SO 2 and SO 3 emissions were also examined for both air-and oxy-firing conditions.• The investigation of O 2 /CO 2 and O 2 /N 2 environments on SO 2 emissions during coal combustion in a bench-scale single-particle fluidized-bed reactor (Subtask 3.5). Moreover, the sulfation mechanisms of limestone in O 2 /CO 2 and O 2 /N 2 environments were studied, and a generalized gassolid and diffusion-reaction single-particle model was developed to s...

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“…Oxy-fuel combustion has the following advantages: (1) up to 95% CO 2 concentration in the dry flue gas; (2) improved boiler efficiency; (3) reduced power consumption in flue gas treatment because of the small amount of flue gas involved; and (4) saved denitrogenation equipment and process. 4,5 However, the high cost of oxygen production limits the implementation of oxycombustion. Therefore, significant reduction in the cost of oxygen production is important for the viability of oxy-fuel combustion power plants in the future when CO 2 capture becomes a necessity.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of SrCo_1-xFe_xO_3-_δPerovskite Powders with Improved O₂/CO₂Production Performance for Oxyfuel Combustion

Shen¹,

Zheng²,

Luo³

et al. 2014

Bulletin of the Korean Chemical Society

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Perovskite-type oxides are promising oxygen carriers in producing oxygen-enriched CO 2 gas stream for oxyfuel combustion. In this study, a new series of SrCo 1-x Fe x O 3-δ (x = 0.2, 0.4, 0.6, 0.8) was prepared and used to produce O 2 /CO 2 mixture gas. The phase, crystal structure, and morphological properties of SrCo 1-x Fe x O 3-δ were investigated through X-ray diffraction, specific surface area measurements, and environmental scanning electron microscopy. The oxygen desorption performance of SrCo 1-x Fe x O 3-δ was studied in a fixed-bed reactor system. Results showed that the different x values of SrCo 1-x Fe x O 3-δ have no obvious effects on crystalline structure. However, the oxygen desorption performance of SrCo 1-x Fe x O 3-δ is improved by Co doping. Moreover, SrCo 0.8 Fe 0.2 O 3-δ synthesized via a new EDTA method has a larger BET surface area (40.396 m 2 /g), smaller particle size (48.3 nm), and better oxygen production performance compared with that synthesized through a liquid citrate method.

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NO x and SO 2 emissions from O 2 /CO 2 recycle coal combustion

Cited by 275 publications

References 2 publications

On the structure of the near field of oxy-fuel jet flames using Raman/Rayleigh laser diagnostics

On the structure of the near field of oxy-fuel jet flames using Raman/Rayleigh laser diagnostics

Oxy-coal Combustion Studies

Characteristics of SrCo_1-xFe_xO_3-_δPerovskite Powders with Improved O₂/CO₂Production Performance for Oxyfuel Combustion

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NO x and SO 2 emissions from O 2 /CO 2 recycle coal combustion

Cited by 275 publications

References 2 publications

On the structure of the near field of oxy-fuel jet flames using Raman/Rayleigh laser diagnostics

On the structure of the near field of oxy-fuel jet flames using Raman/Rayleigh laser diagnostics

Oxy-coal Combustion Studies

Characteristics of SrCo1-xFexO3-δPerovskite Powders with Improved O2/CO2Production Performance for Oxyfuel Combustion

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Characteristics of SrCo_1-xFe_xO_3-_δPerovskite Powders with Improved O₂/CO₂Production Performance for Oxyfuel Combustion