Differences in reactivity of pulverised coal in air (O2/N2) and oxy-fuel (O2/CO2) conditions

Rathnam, Renu Kumar; Elliott, Liza; Wall, Terry; Liu, Yinghui; Moghtaderi, Behdad

doi:10.1016/j.fuproc.2009.02.009

Cited by 269 publications

(183 citation statements)

References 12 publications

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“…At higher temperatures, however, in CO 2 atmosphere char-CO 2 gasification was observed, which is also in accordance with the results obtained by Rathnam et al [37]. At the temperature used in the present study for obtaining the chars (1273 K), gasification process could therefore occur at some extent, which would affect the char characteristics.…”

Section: Kinetic Parameterssupporting

confidence: 92%

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

Gil

Riaza

Álvarez

et al. 2012

Energy

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The thermal reactivity and kinetics of five coal chars, a biomass char, and two coal/biomass char blends in an oxy-fuel combustion atmosphere (30%O 2 -70%CO 2 )were studied using the non-isothermal thermogravimetric method at three heating rates.Fuel chars were obtained by devolatilization in an entrained flow reactor at 1273 K under N 2 and CO 2 atmospheres.Three nth-order representative gas-solid models -the volumetric model (VM), the grain model (GM) and the random pore model (RPM) -were employed to describe the reactive behaviour of the chars. The RPM model was found to be the best for describing the reactivity of the high rank coal chars, while VM was the model that best described the reactivity of the bituminous coal chars, the biomass char and the coal-biomass blend char. The kinetic parameters of the chars obtained in N 2 and CO 2 in an oxy-fuel combustion atmosphere with 30% of oxygen were compared, but no relevant differences were observed. The behaviour of the blend of the bituminous coal (90%wt.) and the biomass (10%wt.) chars resembled that of the individual coal concealing the effect of the biomass. Likewise, no interaction was detected between the high rank coal and the biomass chars during oxy-fuel combustion of the blend.

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Section: Kinetic Parameterssupporting

confidence: 92%

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

Gil

Riaza

Álvarez

et al. 2012

Energy

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“…The greater mass loss observed after devolatilization in the CO 2 atmosphere could have been caused by the gasification reaction between the char and CO 2 . Previous works in literature [7][8][9] reported higher apparent volatile yield values after devolatilization of coal at temperatures of 1000-1400 ºC under CO 2 than under N 2 and they attributed this effect to the char-CO 2 gasification reaction. However, other authors [8,12] obtained slightly lower values after devolatilization in CO 2 at lower temperatures (800-1000 ºC), since the gasification reaction rate was considered to be not significant at low temperature.…”

Section: Apparent Volatile Yieldmentioning

confidence: 88%

“…They have studied the differences in the chars obtained by devolatilization in N 2 and CO 2 in drop tube furnaces or entrained flow reactors in order to elucidate the firing differences between a conventional combustion process and the oxy-fuel combustion process. Thus, Rathnam et al [7] studied the differences of coal chars obtained after devolatilization in N 2 and CO 2 in a drop tube furnace (DTF) at 1400 ºC. Li et al [8] compared the coal chars obtained in N 2 and CO 2 atmospheres in a DTF at 800-1400 ºC.…”

Section: Introductionmentioning

confidence: 99%

Biomass devolatilization at high temperature under N2 and CO2: Char morphology and reactivity

Gil

Riaza

Álvarez

et al. 2015

Energy

116

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“…However, the addition of CO2 weakened the interaction between H2 and the char matrix and increased the H2 fluidity (Pilon and Lavoie 2013). In addition, the specific surface area and pore volume of the char were increased to different degrees in CO2 atmosphere, meaning that the char gasification reaction was promoted more fully (Borrego et al 2009;Rathnam et al 2009;Guizani et al 2013). After a certain amount of CO2 was added, the H2 yield was not much changed for similar reasons.…”

Section: Resultsmentioning

confidence: 99%

Experimental Study on the Gasification Characteristics of Biomass with CO2/Air in an Entrained-flow Gasifier

Yu¹,

Chen²,

Xu³

et al. 2016

BioResources

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This study explored the gasification characteristics of pine sawdust and rice straw with CO2/air in a bench-scale entrained-flow gasifier. The effects of various gasification parameters, i.e., CO2/C, temperature, and biomass type, on the syngas composition, gasification index, and tar yield were investigated. When compared to air gasification, the CO2/air agent for gasification improved the yield of CO, and it decreased the tar yield and the yield of CO2 produced from biomass. The cold gas efficiency (CGE) of pine sawdust reached 87.06% at the CO2/C equivalence ratio of 0.25, whereas that of rice straw reached 73.35% at the CO2/C equivalence ratio of 0.50. When compared with air gasification, the CO2/air gasification increased the CGE of pine sawdust and rice straw by 4.20% and 9.17%, respectively. However, excessive CO2 was unfavorable to the gasification process. As the temperature increased, the yields of CO and H2 increased, and the tar yield decreased, thus improving the syngas quality. This study indicated that the addition of the proper level of CO2 for gasification improved the overall gasification efficiency. Moreover, the improvement for rice straw (herbaceous plant) was more noteworthy than for pine sawdust (woody plant).

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Differences in reactivity of pulverised coal in air (O2/N2) and oxy-fuel (O2/CO2) conditions

Cited by 269 publications

References 12 publications

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

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

Biomass devolatilization at high temperature under N2 and CO2: Char morphology and reactivity

Experimental Study on the Gasification Characteristics of Biomass with CO2/Air in an Entrained-flow Gasifier

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