Burning characteristics of Victorian brown coal under MILD combustion conditions

Saha, M.; Dally, Bassam B.; Medwell, Paul R.; Chinnici, Alfonso

doi:10.1016/j.combustflame.2016.07.026

Cited by 92 publications

(61 citation statements)

References 57 publications

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“…It must be mentioned that the excess O 2 primarily provides a better combustion environment, benefitting the reaction kinetics and reducing the penalty from unburnt solid fuel. Some studies have shown that the burnout of coal was reduced under MILD combustion condition . The carbon burnout is significantly affected by the particle residence time, particle size, and reaction rate .…”

Section: Resultsmentioning

confidence: 99%

“…MILD combustion is flameless, and it has the potential to offer ultralow pollutant emission, high thermal efficiency, enhanced combustion stability and fuel flexibility . MILD combustion has been successfully applied for gaseous fuels as well as pulverized fuels (with size 50‐120 μm) . Kiga et al successfully implemented the MILD combustion of high volatile pulverized coal using a drop tube furnace.…”

Section: Introductionmentioning

confidence: 99%

“…[21][22][23] MILD combustion has been successfully applied for gaseous fuels [24][25][26][27] as well as pulverized fuels (with size 50-120 μm). [28][29][30][31] Kiga et al 32 successfully implemented the MILD combustion of high volatile pulverized coal using a drop tube furnace. Suda et al 33 investigated the behavior of pulverized coal in high-temperature air combustion using a burner of 250 kW.…”

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confidence: 99%

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Application of chemical looping air separation for MILD oxy‐combustion in the supercritical power plant with CO₂ capture

Chen

Sun

et al. 2018

Energy Science & Engineering

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Chemical looping air separation (CLAS) is a novel and promising technology for oxygen production. This paper presents the application of CLAS to the supercritical power plant for MILD oxy‐combustion. Compared with the reference conventional supercritical power plant, the power generation efficiency of the CLAS integrated MILD oxy‐combustion plant is only reduced by about ~1.37% points at the baseline case. CO2 compression process imposes additional ~3.97% points efficiency penalty, which is inevitable to all of the CO2 capture technologies. The net power efficiency of the CLAS integrated MILD oxy‐combustion plant is ~37.37%. Even though a higher reduction reactor temperature could boost the power efficiency and a higher oxidization reactor temperature reversely decreases the power efficiency, the influence of reactor temperature is marginal. The performance of CLAS integrated MILD oxy‐combustion plant is not sensitive to excess CO2 and O2 ratio. Different oxygen carriers have different suitable operating region, but possess similar power efficiency. The carbon capture rate of the CLAS integrated MILD oxy‐combustion plant is up to ~100%, resulting in a virtually carbon‐free fossil power plant.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Application of chemical looping air separation for MILD oxy‐combustion in the supercritical power plant with CO₂ capture

Chen

Sun

et al. 2018

Energy Science & Engineering

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“…[2][3][4][5][6][7][8][9][10][11][12][13] The essence of this technology for coal combustion is to achieve strong recirculation of the injected streams so that the coal particles are heated and combusted in a highly substoichiometric condition. Galbiati et al 15 and Saha et al 16 experimentally investigated the fuel-NO formation under MILD conditions burning nitrogen-rich fossil fuels. There is a growing body of research on coal MILD combustions.…”

Section: Introductionmentioning

confidence: 99%

“…The results highlighted the potential of coal MILD combustion for NO x emission reduction owing to the stronger NO reburning mechanism as compared with the conventional combustion. Galbiati et al 15 and Saha et al 16 experimentally investigated the fuel-NO formation under MILD conditions burning nitrogen-rich fossil fuels. The results showed that fuel-NO formation could be significantly reduced, and the extent of the reduction depends on the oxygen excess level.…”

Section: Introductionmentioning

confidence: 99%

Numerical study of further NO _x emission reduction for coal MILD combustion by combining fuel‐rich/lean technology

Zeng

et al. 2019

Int J Energy Res

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Summary This paper numerically examines the feasibility of further reducing NOx emission from a semi‐industrial scale coal MILD (moderate and intense low‐oxygen dilution) combustion furnace by adopting fuel‐rich/lean technology. The implementation is achieved by separating the original fuel jet into two parallel jets which will be used as rich and lean streams. An effort has been made to develop a 13‐step reaction mechanism and NOx evolution UDFs (user defined functions) for better understanding the interactions between MILD combustion and fuel‐rich/lean technology. The experiment of the reference case (Combustion and Flame 156.9 (2009): 1771‐1784) is well reproduced by the present numerical simulation, indicating high reliability of developed models. The validity of the further reduction of NOx emission is assessed by the comparison among inner‐fuel‐rich (IFR), outer‐fuel‐rich (OFR), and reference cases resulting from the adjustment of the fuel supply through the two fuel‐rich/lean jets. The results show that both IFR and OFR configurations succeed in achieving further reduction of NOx emission as compared with the reference case, which stems from both thermal and fuel paths. Specifically, the decrease of thermal‐NO emission originates from the contraction of high‐temperature regions (>1800 K), where nearly 94% reduction occurs within the temperature range of 1800 K and 1950 K while only 6% within 1950 K and 2030 K despite their high temperature sensitivity. The reduction of the fuel‐NO emission is mainly attributed to the promoted NO reduction on char surface and neutralization with HCN and NH3. Generally, the NOx emission can be minimized by enlarging the equivalence ratio difference between rich and lean jets, and the OFR configuration exhibits a higher potential than the IFR counterparts. However, since a relatively high temperature (1623 K) secondary air was used in the experiment, the maximum NOx reduction potential was limited to only 2.5%.

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Experimental research on NO emission with coal preheating combustion technology

Wen

Ouyang

et al. 2020

Asia-Pacific J Chem Eng

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Coal preheating combustion technology was adopted to achieve stable combustion and low NO emission of Shenmu semicoke, and an air‐staging method was also used to further reduce NO emission. A series of experiments have been launched on a 30‐kW coal preheating combustion test rig with a coaxial jet triple channel nozzle. In the study, coal preheated characteristics, combustion behavior, and the formation and destruction mechanisms of NO were discussed. Shenmu semicoke could be preheated up to a temperature above 840°C, and stable combustion was easily established; ~63% of the volatile and 59% of carbon were released and converted into coal gas in the self‐preheating burner. Flame images along the axis of the down‐fired combustor were gained, and the images was dark red without obvious flame fronts. The initial generation of NO in the near field of the preheated fuel nozzle exit had impacts on the NO emission, and lower initial NO generation might result in lower NO emission. By decreasing the inner secondary gas (air), increasing the external secondary air and adding CO2 in the secondary gas, the initial NO could be inhibited effectively, which finally controlled the NO emission. However, the CO emission might increase in turn generally. In the research, the NOX emissions were <180 mg/m3 (@6% O2) with the lowest <80 mg/m3. To achieve an optimal scheme of NO emission and CO emission, some adjustment methods need to be applied synchronously.

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Burning characteristics of Victorian brown coal under MILD combustion conditions

Cited by 92 publications

References 57 publications

Application of chemical looping air separation for MILD oxy‐combustion in the supercritical power plant with CO₂ capture

Application of chemical looping air separation for MILD oxy‐combustion in the supercritical power plant with CO₂ capture

Numerical study of further NO _x emission reduction for coal MILD combustion by combining fuel‐rich/lean technology

Experimental research on NO emission with coal preheating combustion technology

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Burning characteristics of Victorian brown coal under MILD combustion conditions

Cited by 92 publications

References 57 publications

Application of chemical looping air separation for MILD oxy‐combustion in the supercritical power plant with CO2 capture

Application of chemical looping air separation for MILD oxy‐combustion in the supercritical power plant with CO2 capture

Numerical study of further NO x emission reduction for coal MILD combustion by combining fuel‐rich/lean technology

Experimental research on NO emission with coal preheating combustion technology

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Application of chemical looping air separation for MILD oxy‐combustion in the supercritical power plant with CO₂ capture

Application of chemical looping air separation for MILD oxy‐combustion in the supercritical power plant with CO₂ capture

Numerical study of further NO _x emission reduction for coal MILD combustion by combining fuel‐rich/lean technology