Study of Activation of Coal Char

Suuberg, E M; Kulaots, I; Aarna, I; Callejo, M; Hsu, A

doi:10.2172/875822

Cited by 7 publications

(12 citation statements)

References 33 publications

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“…Oxygen partial pressure variations from 1 to 21 kPa did not influence these results, consistent with results from another type of char [34]. All of the coal chars exhibit a steep increase in surface area with burn-off, near zero burnoff (the fresh char state).…”

Section: Surface Area Development In Laboratory Chars Under Zone I Cosupporting

confidence: 84%

“…Adsorption of N2 and CO2 were performed at 77 K and 195 K, respectively. Nitrogen was the preferred adsorbate for reasons discussed previously [7,18,19], and reviewed below. Results obtained on a bituminous coal-derived fly ash carbon are shown for comparison (because of fuel switching at the utility, the precise identity of the parent coal was unknown, as is typical of commercial ash samples).…”

Section: Porosity Characterizationmentioning

confidence: 99%

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Study of Activation of Coal Char

Suuberg¹

2003

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Section: Surface Area Development In Laboratory Chars Under Zone I Cosupporting

confidence: 84%

Section: Porosity Characterizationmentioning

confidence: 99%

Study of Activation of Coal Char

Suuberg¹

2003

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“…The results of the studies (Agrawal and Sears, 1980;Floes et al, 1988;Johnson, 1975;Kulaots et al, 2004;Suuberg et al, 2003;) and our study results were used for verification of the proposed Equations (26) and (27). In Table 3, selected initial parameters are presented.…”

Section: Determination Of Internal Surface Area Changesmentioning

confidence: 61%

“…On the basis of Niwka coal experiments and literature data from Johnson (1975), Agrawal andSears (1980), Floes et al (1988), Suuberg et al (2003) and Kulaots et al (2004) a comparative analysis of matching the model to the assumed porosity change plots (for n=0 and n=1) was performed and presented in Figure 6. The analysis results show that a much better agreement is achieved for the value n=1 which will be used in further analyses of changes in total active centres.…”

Section: Determination Of Internal Surface Area Changesmentioning

confidence: 99%

Changes in total active centres on particle surfaces during coal pyrolysis, gasification and combustion

Gil¹,

Mocek²,

Bialik³

2011

Chemical and Process Engineering

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In the paper, on the basis of our studies and the available literature data, a model of changes in the number of active centers corresponding to the structure of the reactive coal particle has been developed. A new distribution function that links the specific surface area of a particle with its porosity and reaction degree has been proposed. An equation for estimation of changes in this parameter during the reaction, on the basis of the initial value, has been presented. In the range of our data and the analysis of the literature data, the model, with satisfactory accuracy, describes internal structural changes of coal and coal char particles. The present results may constitute a basis for complex modelling of coal conversion processes.Based on the results it was found that the total active centres are related to the internal surface area and porosity of the particle. For a specific coal type, this value depends on the porosity, true density and size of the particle. Changes in total active centres, when these structural properties during thermal conversion of coal are considered, are described in equations.

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“…where _ m 00 C is the char surface oxidation rate per unit area, DH C is the heat of combustion of char, h is the convective heat transfer coefficient (10 W/m 2 K, estimated from laminar natural convection over a vertical plate), and e is the surface emissivity (0.6-0.7, taken from [15]). …”

Section: Solid Phase Modelmentioning

confidence: 99%