Kinetic models for the oxy-fuel combustion of coal and coal/biomass blend chars obtained in N2 and CO2 atmospheres

Gil, M.V.; Riaza, Juan; Álvarez, L.; Pevida, C.; Pís, J.J.; Rubiera, F.

doi:10.1016/j.energy.2012.10.033

Cited by 88 publications

(39 citation statements)

References 37 publications

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“…[20] resulted in no significant difference in reactivity. Gil et al [17,21] also performed TGA experiments and observed no or just a slightly higher reactivity of the N 2 -chars. Rathnam et al [11] obtained partially similar results comparing burn-out degree of the chars in different oxygencontaining N 2 /CO 2 atmospheres at twice the residence times: two of the four examined samples showed a similar burn-out in both atmospheres, while in CO 2 -atmospheres the burn-out degree was higher for the other two coals.…”

Section: Introductionmentioning

confidence: 94%

Effects of oxy-fuel conditions on the products of pyrolysis in a drop tube reactor

Heuer

Senneca

Wütscher

et al. 2016

Fuel Processing Technology

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Section: Introductionmentioning

confidence: 94%

Effects of oxy-fuel conditions on the products of pyrolysis in a drop tube reactor

Heuer

Senneca

Wütscher

et al. 2016

Fuel Processing Technology

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“…Larger CO concentrations, formed partly due to incomplete combustion of the volatiles, and partly driven from char CO 2 gasification reactions, would also contribute to the worsening of the burning properties of the coal, by forming a persistent cloud around the particle, thereby preventing the access of oxygen to the surface of the particle [17].…”

Section: Effect Of the Diluent Background Gases (N 2 And Co 2 ) And Omentioning

confidence: 99%

“…These coal particles ignited and burned heterogeneously by direct attack of oxygen on their surfaces. Due to the known low reactivity of the anthracite AC particles [17], their ignition was delayed. The color of the particles changed from dark (black) to bright (nearly-white) as their surfaces became incandescent; this change occurred gradually over a few milliseconds.…”

Section: High-speed Cinematography Stillsmentioning

confidence: 99%

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

191

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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“…RPM, URCM and VM models have been used to study the coal char gasification, and a series of achievements have been reported [2][3][4][5][13][14][15][16][17]22,24]. In this paper, a new mathematical treatment of calculation kinetic parameters has been established to reduce the error caused by dealing with experimental data.…”

Section: Analysis Of Calculation Methodsmentioning

confidence: 99%

“…In order to evaluate accuracy of different models, the deviation caused by different models is calculated by Eq. (14) [22].…”

Section: Samplementioning

confidence: 98%

Investigation of non-isothermal and isothermal gasification process of coal char using different kinetic model

Wang

Zhang

Shao

et al. 2015

International Journal of Mining Science and Technology

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a b s t r a c tIsothermal and non-isothermal gasification kinetics of coal char were investigated by using thermogravimetric analysis (TGA) in CO 2 atmosphere, and the experimental data were interpreted with the aids of random pore model (RPM), unreacted shrinking core model (URCM) and volume model (VM). With the increase of heating rate, gasification curve moves into high temperature zone and peak rate of gasification increases; with the increase of gasification temperature, gasification rate increases and the total time of gasification is shortened. The increase of both heating rate and gasification temperature could improve gasification process of coal char. Kinetics analysis indicates that experimental data agree better with the RPM than with the other two models. The apparent activation energy of non-isothermal and isothermal gasification of coal char using RPM is 193.9 kJ/mol and 212.6 kJ/mol respectively, which are in accordance with reported data. Gasification process of coal char under different heating rates and different temperatures are predicted by the RPM derived in this study, and it is found that the RPM predicts the reaction process satisfactorily.

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Kinetic models for the oxy-fuel combustion of coal and coal/biomass blend chars obtained in N2 and CO2 atmospheres

Cited by 88 publications

References 37 publications

Effects of oxy-fuel conditions on the products of pyrolysis in a drop tube reactor

Effects of oxy-fuel conditions on the products of pyrolysis in a drop tube reactor

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

Investigation of non-isothermal and isothermal gasification process of coal char using different kinetic model

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