The Effect of Oxygen Staging on Nitrogen Conversion in Oxy-Fuel CFB Environment

Jankowska, Sylwia; Czakiert, Tomasz; Krawczyk, Grzegorz; Borecki, P.; Jesionowski, Ł.; Nowak, Wojciech

doi:10.2478/cpe-2014-0036

Cited by 16 publications

(9 citation statements)

References 12 publications

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“…Fuel NO x was the main source of NO x under the circulating fluidized bed combustion, and fuel N will be mainly thermal decomposition into NH 3 and HCN and other intermediates . As Figure shows, with the increase of the oxygen concentration in the oxygen-enriched combustion, the NO concentration increases, which is consistent with the former reports. , As a result of the same heat input during the oxy-coal combustion, as the oxygen concentration increased, the flue gas volume decreased . Therefore, NO emissions decreased.…”

Section: Resultssupporting

confidence: 85%

“…16 As Figure 7 shows, with the increase of the oxygen concentration in the oxygen-enriched combustion, the NO concentration increases, which is consistent with the former reports. 38,39 As a result of the same heat input during the oxycoal combustion, as the oxygen concentration increased, the flue gas volume decreased. 15 Therefore, NO emissions decreased.…”

Section: Co 2 Emissions Undermentioning

confidence: 99%

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Inner Relationship between CO, NO, and Hg in a 6 kW_th Circulating Fluidized Bed Combustor under an O₂/CO₂ Atmosphere

Wang

Duan

et al. 2016

Energy Fuels

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Combustion experiments of semianthracite coal were conducted on a 6 kWth oxy-fuel circulating fluidized bed combustor. The inner relationship between CO, NO, and Hg in the combustor under an O2/CO2 atmosphere was explored. The results demonstrate that all temperatures are lower under a 21% O2/79% CO2 atmosphere than those under an air atmosphere. In oxy-coal combustion, the increasing oxygen concentration can increase CO emission. NO emission in oxy-coal is much lower than that in air combustion as a result of coal particle combustion generating less oxygen status under a 21% O2/79% CO2 atmosphere. The percentage of mercury oxidation is higher under air–coal combustion than that under 21% O2/79% CO2–coal combustion, because the specific heat of CO2 is higher in 21% O2/79% CO2 than that in air. The increase of the oxygen concentration under oxy-coal combustion leads to the total reducing atmosphere decrease, which is suitable for the mercury oxidation. These results are very significant for selection of operating conditions for an oxy-coal circulating fluidized bed.

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Section: Resultssupporting

confidence: 85%

Section: Co 2 Emissions Undermentioning

confidence: 99%

Inner Relationship between CO, NO, and Hg in a 6 kW_th Circulating Fluidized Bed Combustor under an O₂/CO₂ Atmosphere

Wang

Duan

et al. 2016

Energy Fuels

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“…Our experiments showed that switching to oxy-fuel combustion did not alter the NO x emissions. The nitrogen conversion ratio to NO x was up to 24%, similar to results from Jankowska et al [32] with bituminous coal (20-25%). However, Pikkarainen et al [33] measured higher nitrogen conversion ratios (28-50%).…”

Section: Sulfur Oxides Emissionssupporting

confidence: 89%

“…One advantage of oxy-fuel technology is its potentially lower NO x production. Results from different experimental facilities are rather diverse [18,[29][30][31][32][33]. Overall, the results indicate that nitrogen behavior in the oxy-fuel mode is similar to combustion in air and no drastic changes are expected in fuel nitrogen conversion to oxides.…”

Section: Introductionmentioning

confidence: 86%

Ash and Flue Gas from Oil Shale Oxy-Fuel Circulating Fluidized Bed Combustion

et al. 2018

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Carbon dioxide emissions are considered a major environmental threat. To enable power production from carbon-containing fuels, carbon capture is required. Oxy-fuel combustion technology facilitates carbon capture by increasing the carbon dioxide concentration in flue gas. This study reports the results of calcium rich oil shale combustion in a 60 kW th circulating fluidized bed (CFB) combustor. The focus was on the composition of the formed flue gas and ash during air and oxy-fuel combustion. The fuel was typical Estonian oil shale characterized by high volatile and ash contents. No additional bed material was used in the CFB; the formed ash was enough for the purpose. Two modes of oxy-fuel combustion were investigated and compared with combustion in air. When N 2 in the oxidizer was replaced with CO 2 , the CFB temperatures decreased by up to 100 • C. When oil shale was fired in the CFB with increased O 2 content in CO 2 , the temperatures in the furnace were similar to combustion in air. In air mode, the emissions of SO 2 and NO x were low (<14 and 141 mg/Nm 3 @ 6% O 2 , respectively). Pollutant concentrations in the flue gas during oxy-fuel operations remained low (for OXY30 SO 2 < 14 and NO x 130 mg/Nm 3 @ 6% O 2 and for OXY21 SO 2 23 and NO x 156 mg/Nm 3 @ 6% O 2 ). Analyses of the collected ash samples showed a decreased extent of carbonate minerals decomposition during both oxy-fuel experiments. This results in decreased carbon dioxide emissions. The outcomes show that oxy-fuel CFB combustion of the oil shale ensures sulfur binding and decreases CO 2 production.

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“…Moreover, the process can decrease emissions of gaseous pollutants, especially if nitrogen oxides (NOx) are taken into account (Jankowska et al, 2014;Toftegaard et al, 2010) Currently, the application of oxy-fuel technology in big-, industrial-scale is still being discussed and considered. The construction of new oxy-fuel boilers is taken into account, although retrofitting an existing power plant to an oxy-firing system (Fei et al, 2015;Fry et al, 2011) provides another solution.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Transition Time From Air to Oxy-Combustion

Lasek¹,

Lajnert²,

Głód³

et al. 2015

Chemical and Process Engineering

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In this paper some issues of the transition process from air-to oxy-combustion were investigated. Advantages of flexible combustion were described. Flexible combustion tests carried out at four European plants and five plants outside Europe of different scales of process and test parameters were presented. An analysis of the transition time from air to oxy-combustion of different laboratory and pilot scale processes was carried out. The "first-order + dead time" approach was used as a model to describe transition process. Transitional periods between combustion modes and characteristic parameters of the process were determined. The transition time depends not only on the facility's capacity but also it is impacted by specific operational parameters.

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The Effect of Oxygen Staging on Nitrogen Conversion in Oxy-Fuel CFB Environment

Cited by 16 publications

References 12 publications

Inner Relationship between CO, NO, and Hg in a 6 kW_th Circulating Fluidized Bed Combustor under an O₂/CO₂ Atmosphere

Inner Relationship between CO, NO, and Hg in a 6 kW_th Circulating Fluidized Bed Combustor under an O₂/CO₂ Atmosphere

Ash and Flue Gas from Oil Shale Oxy-Fuel Circulating Fluidized Bed Combustion

Analysis of the Transition Time From Air to Oxy-Combustion

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The Effect of Oxygen Staging on Nitrogen Conversion in Oxy-Fuel CFB Environment

Cited by 16 publications

References 12 publications

Inner Relationship between CO, NO, and Hg in a 6 kWth Circulating Fluidized Bed Combustor under an O2/CO2 Atmosphere

Inner Relationship between CO, NO, and Hg in a 6 kWth Circulating Fluidized Bed Combustor under an O2/CO2 Atmosphere

Ash and Flue Gas from Oil Shale Oxy-Fuel Circulating Fluidized Bed Combustion

Analysis of the Transition Time From Air to Oxy-Combustion

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Product

Resources

About

Inner Relationship between CO, NO, and Hg in a 6 kW_th Circulating Fluidized Bed Combustor under an O₂/CO₂ Atmosphere

Inner Relationship between CO, NO, and Hg in a 6 kW_th Circulating Fluidized Bed Combustor under an O₂/CO₂ Atmosphere