Combustion behavior of single particles from three different coal ranks and from sugar cane bagasse in O2/N2 and O2/CO2 atmospheres

Khatami, Reza; Stivers, Chris; Joshi, Kulbhushan; Levendis, Yiannis A.; Sarofim, Adel F.

doi:10.1016/j.combustflame.2011.09.009

Cited by 227 publications

(235 citation statements)

References 46 publications

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“…The combustion and emission studies of bituminous coals has been well-documented in the aforementioned studies of Khatami et al and Kazanc et al in this laboratory [4,5,6] as well as in other studies including those of [7][8][9][10]. However, studies on anthracite and semi-anthracite coal particle ignition and combustion are scarce.…”

Section: Introductionmentioning

confidence: 93%

“…Each data point in this figure represents average ignition temperatures from at least 8 randomly-selected particles. Ignition temperature data for lignite coal particles from a previous study in this laboratory [4] are also displayed in this figure for comparison. Fig.9 illustrates that higher rank coals ignited at higher temperatures.…”

Section: (B) Ignition Temperaturesmentioning

confidence: 99%

“…Single particle combustion modes were discussed comprehensively in previous studies [4,5,20]. In summary, Howard and Essenhigh [20] studied the combustion phenomena of coal particles and proposed a model to assess whether the burning of the volatiles and char takes place sequentially or simultaneously.…”

Section: Combustion Modementioning

confidence: 99%

“…In summary, Howard and Essenhigh [20] studied the combustion phenomena of coal particles and proposed a model to assess whether the burning of the volatiles and char takes place sequentially or simultaneously. Khatami et al [4,5] employed that model to a number of coals from different ranks in a variety of oxygen-nitrogen and oxygen-carbon dioxide environments. The terms two-mode and one-mode combustion were used to respectively signify events where gas-phase combustion of the volatiles takes place in an enveloping flame, prior to heterogeneous char particle combustion, and where volatile and solid char combustion take place simultaneously.…”

Section: Combustion Modementioning

confidence: 99%

“…Previous work in this laboratory contrasted the combustion behaviors of single solid fuel particles of a bituminous high-volatile type-A coal, three low rank coals (low carbon content and low heating value coals): a sub-bituminous and two different lignites, as well as biomass (sugarcane bagasse) under air and under simulated dry oxyfiring conditions [4,5]. This work aims at examining the combustion behavior of additional bituminous coals (high-and medium-volatile types-B) as well high rank coals (high carbon content and high heating value coals), i.e., anthracite and semi-anthracite.…”

Section: Introductionmentioning

confidence: 99%

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Single particle ignition and combustion of anthracite, semi-anthracite and bituminous coals in air and simulated oxy-fuel conditions

Riaza

Khatami

Levendis

et al. 2014

Combustion and Flame

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188

111

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A fundamental investigation has been conducted on the combustion behavior of single particles (75-150 μm) of four coals of different ranks: anthracite, semi-anthracite, medium-volatile bituminous and high-volatile bituminous. A laboratory-scale transparent laminar-flow drop-tube furnace was used to burn the coals, electricallyheated to 1400 K. The experiments were performed in different combustion atmospheres: air (21%O 2 /79%N 2 ) and four simulated dry oxy-fuel conditions: 21%O 2 /79%CO 2 , 30%O 2 /70%CO 2 , 35%O 2 /65%CO 2 and 50%O 2 /50%CO 2 . The ignition and combustion of single particles was observed by means of three-color pyrometry and high-speed high-resolution cinematography to obtain temperature-time histories and record combustion behavior. On the basis of the observations made with these techniques, a comprehensive examination of the ignition and combustion behavior of these fuels was achieved. Higher rank coals (anthracite and semi-anthracite) ignited heterogeneously on the particle surface, whereas the bituminous coal particles ignited homogeneously at the gas phase. Moreover, deduced ignition temperatures increased * Corresponding author: Tel.: 001 (617) 373-3806; Fax: 001 (617) 373-2921 E-mail address: y.levendis@neu.edu 2 with increasing coal rank and decreased with increasing oxygen concentrations.Strikingly disparate combustion behaviors were observed depending on the coal rank.The combustion of bituminous coal particles took place in two phases. First, volatiles evolved, ignited and burned in luminous enveloping flames. Upon extinction of these flames, the char residues ignited and burned. In contrast, the higher rank coal particles ignited and burned heterogeneously. The replacement of the background N 2 gas of air with CO 2 (i.e., changing from air to an oxy-fuel atmosphere) at the same oxygen mole fraction impaired the intensity of combustion. It reduced the combustion temperatures and lengthened the burnout times of the particles. Increasing the oxygen mole fraction in CO 2 to 30-35% restored the intensity of combustion to that of air for all the coals studied. Volatile flame burnout times increased linearly with the volatile matter content in the coal in both air and all oxygen mole fractions in CO 2 . On the other hand, char burnout times increased linearly or quadratically versus carbon content in the coal, depending on the oxygen mole fraction in the background gas.

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Section: Introductionmentioning

confidence: 93%

Section: (B) Ignition Temperaturesmentioning

confidence: 99%

Section: Combustion Modementioning

confidence: 99%

Section: Combustion Modementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Single particle ignition and combustion of anthracite, semi-anthracite and bituminous coals in air and simulated oxy-fuel conditions

Riaza

Khatami

Levendis

et al. 2014

Combustion and Flame

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188

111

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Oxyfuel Combustion forCO₂Capture

Yan

2015

Handbook of Clean Energy Systems

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Oxyfuel combustion is one of the technologies for carbon dioxide ( CO 2 ) capture and storage ( CCS ) in fossil‐fuel‐based power systems to mitigate global greenhouse gas ( GHG ) emissions. When introducing oxyfuel combustion into the power systems, physical and chemical processes of the combustion differ from conventional combustion, and the energy penalty for CCS has significant impacts on the system operation and performance, similar to combustion process, heat transfer, flue gas properties, and emission control. Around these topics, dozens of oxyfuel‐related projects were launched within this decade in the worldwide, and many techno‐economic assessments for oxyfuel technology including competitive technologies (pre‐/post‐combustion and emerging technologies) are continuously being published. Although the technologies for oxyfuel combustion are relatively well understood today, it is only investigated experimentally in lab and pilot‐scale combustion equipment. The estimated costs of electricity and CO 2 avoidance costs are varied by uncertainties from economical assessments from different referenced databases and from restricted regulation of different countries and regions. Therefore, all addressed issues must be clarified and proved to be feasible deployment for the commercial scale CCS plants to cope with emission targets according to Copenhagen Accord to reduce GHG emission and mitigate world temperature rising.

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The competitive reaction mechanism between oxidation and pyrolysis consumption during low‐rank coal combustion at lean‐oxygen conditions: A quantitative calculation based on thermogravimetric analyses

Wang

Xin

et al. 2018

Can J Chem Eng

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The evolution of the oxidation-pyrolysis competitive mechanism during low-rank coal combustion at lean-oxygen conditions determines the development of the coalfield fires and the burning loss rate of the coal resource. In the present work, the mass increments of oxygen-chemisorption were measured and calculated firstly. An abstract shrinking core model was built for distinguishing the oxidation and pyrolysis pathways. On this basis, the consumption rates of oxidation and pyrolysis were respectively calculated with the TGA data obtained under the lean-oxygen gradient of 21-0 %. The results demonstrate that the oxidation path gradually delays in temperature while the pyrolysis exhibits great temperature stability as the oxygen concentration decreases. Besides, the significant transition of the competitive consumption mechanism exists below 9 % for the oxidation phase before ignition and 5 % for the combustion phase after ignition, respectively. Two temperature indicators of T C1 and T C2 for guiding the optimal fire extinguishing schemes based on the actual oxygen concentrations and temperatures are proposed. Furthermore, 1 % is identified as the limiting oxygen concentration for the development of the coalfield fires where the ignition mechanisms of both the HST and WD coal transform into the homogeneous ignition. The WD lignite, which always maintains the coke state as the burnout mechanism, holds higher reactivity but wider dispersion degrees of combustion compared with the HST sub-bituminous coal.

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Combustion behavior of single particles from three different coal ranks and from sugar cane bagasse in O2/N2 and O2/CO2 atmospheres

Cited by 227 publications

References 46 publications

Single particle ignition and combustion of anthracite, semi-anthracite and bituminous coals in air and simulated oxy-fuel conditions

Single particle ignition and combustion of anthracite, semi-anthracite and bituminous coals in air and simulated oxy-fuel conditions

Oxyfuel Combustion forCO₂Capture

The competitive reaction mechanism between oxidation and pyrolysis consumption during low‐rank coal combustion at lean‐oxygen conditions: A quantitative calculation based on thermogravimetric analyses

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Combustion behavior of single particles from three different coal ranks and from sugar cane bagasse in O2/N2 and O2/CO2 atmospheres

Cited by 227 publications

References 46 publications

Single particle ignition and combustion of anthracite, semi-anthracite and bituminous coals in air and simulated oxy-fuel conditions

Single particle ignition and combustion of anthracite, semi-anthracite and bituminous coals in air and simulated oxy-fuel conditions

Oxyfuel Combustion forCO2Capture

The competitive reaction mechanism between oxidation and pyrolysis consumption during low‐rank coal combustion at lean‐oxygen conditions: A quantitative calculation based on thermogravimetric analyses

Contact Info

Product

Resources

About

Oxyfuel Combustion forCO₂Capture