Analysis of the flame formed during oxidation of pulverized coal by an O2CO2 mixture

Nozaki, Tomohiro; Takano, Shinichi; Kiga, Takashi; Omata, Kouji; Kimura, Naokazu

doi:10.1016/s0360-5442(96)00143-0

Cited by 107 publications

(53 citation statements)

References 2 publications

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“…NO x emissions from coal combustion in O 2 /CO 2 combustion were found to be smaller than those from conventional coal-air combustion [141,145,146]. The flame propagation speed of pulverized coal cloud was measured in a micro-gravity combustion chamber and was found to be much lower in an O 2 /CO 2 atmosphere than in an O 2 /N 2 atmosphere, however, it could be increased by increasing O 2 concentration in CO 2 [143].…”

Section: Advantages Disadvantagesmentioning

confidence: 92%

Coal gasification in CO2 atmosphere and its kinetics since 1948: A brief review

Irfan

Usman

Kusakabe

2011

Energy

425

229

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Section: Advantages Disadvantagesmentioning

confidence: 92%

Coal gasification in CO2 atmosphere and its kinetics since 1948: A brief review

Irfan

Usman

Kusakabe

2011

Energy

425

229

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“…Pilot scale and demonstration plant studies were subsequently carried out by Argonne National Laboratories and the Energy and Environmental Research Corporation (Payne et al, 1989;Abele et al, 1987;Weller et al, 1985) with corresponding numerical modelling investigations (Berry and Wolsky, 1986;Wang et al, 1988). During the 1990s, the technology received further interest for greenhouse gas and NO x reduction with pilot-scale studies conducted in a project led by the International Flame Research Foundation (Woycenko et al, 1995) and in work carried out by Ishikawajima Harima Engineering to consider oxyfuel retrofits to Japanese boilers (Nozaki et al, 1997;Kiga et al, 1997;Kimura et al, 1995;Nakayama et al, 1992). Oxyfuel studies led by CAN-MET began in the late 1990s using their vertical combustor research facility (Douglas et al, 2001) with computational fluid dynamic (CFD) modelling studies following later (Chui et al, 2003(Chui et al, , 2004.…”

Section: Introductionmentioning

confidence: 99%

Combustion modelling opportunities and challenges for oxy-coal carbon capture technology

Edge

Gharebaghi

Irons³

et al. 2011

Chemical Engineering Research and Design

161

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“…This improvement was attributed to reburning of recycled NO X . Nozaki et al (1997) in a follow up paper report that NO X in the flame (mostly recycled NO X ) was reduced rapidly to HCN or NH 3 in the early stages of coal combustion. Oxygen injection at the burner centerline raised near burner gas temperatures, causing increased devolatilization.…”

Section: Review Of No X Formation In Oxy-combustionmentioning

confidence: 97%

“…In furnace areas other than the flame, CO 2 and H 2 O may become more important radiators as ash emittance decreases with increased carbon conversion (Nozaki et al, 1997). There is some difference in gas emittance between wet and dry recycled oxy-fuel flue gas, and air-fired flue gas (Khare et al, 2005).…”

Section: Review Of No X Formation In Oxy-combustionmentioning

confidence: 99%

A Mechanistic Investigation of Nitrogen Evolution and Corrosion with Oxy-Combustion

Tree

Mackrory²,

Fletcher³

2008

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A premixed, staged, down-fired, pulverized coal reactor and a flat flame burner were used to study the evolution of nitrogen in coal contrasting differences in air and oxy-combustion. In the premixed reactor, the oxidizer was staged to produce a fuel rich zone followed by a burnout zone. The initial nominal fuel rich zone stoichiometric ratio (S.R.) of 0.85 selected produced higher NO reductions in the fuel rich region under oxy-combustion conditions. Air was found to be capable of similar NO reductions when the fuel rich zone was at a much lower S.R. of 0.65. At a S.R. of 0.85, oxy-combustion was measured to have higher CO, unburned hydrocarbons, HCN and NH 3 in the fuel rich region than air at the same S.R. There was no measured difference in the initial formation of NO. The data suggest devolatilization and initial NO formation is similar for the two oxidizers when flame temperatures are the same, but the higher CO 2 leads to higher concentrations of CO and nitrogen reducing intermediates at a given equivalence ratio which increases the ability of the gas phase to reduce NO. These results are supported by flat flame burner experiments which show devolatilization of nitrogen from the coal and char to be similar for air and oxy-flame conditions at a given temperature. A model of premixed combustion containing devolatilization, char oxidation and detailed kinetics captures most of the trends seen in the data. The model suggests CO is high in oxy-combustion because of dissociation of CO 2 . The model also predicts a fraction (up to 20%, dependent on S.R.) of NO in air combustion can be formed via thermal processes with the source being nitrogen from the air while in oxy-combustion equilibrium drives a reduction in NO of similar magnitude. The data confirm oxy-combustion is a superior oxidizer to air for NO control because NO reduction can be achieved at higher S.R. producing better char burnout in addition to NO from recirculated flue gas being reduced as it passes back through the flame.4

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Analysis of the flame formed during oxidation of pulverized coal by an O2CO2 mixture

Cited by 107 publications

References 2 publications

Coal gasification in CO2 atmosphere and its kinetics since 1948: A brief review

Coal gasification in CO2 atmosphere and its kinetics since 1948: A brief review

Combustion modelling opportunities and challenges for oxy-coal carbon capture technology

A Mechanistic Investigation of Nitrogen Evolution and Corrosion with Oxy-Combustion

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