CO gasification rate analysis of coal char in entrained flow coal gasifier

Kajitani, Shiro; Suzuki, Norihiro; Ashizawa, Masami; Hará, Saburo

doi:10.1016/j.fuel.2005.07.024

Cited by 257 publications

(144 citation statements)

References 4 publications

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“…On the other side, type and composition of fuel used for char preparation strongly affect the rate of gasification [6,7]. Gasification is usually carried out with air, oxygen and steam mixtures.…”

Section: Introductionmentioning

confidence: 99%

“…However, nowadays when there is a worldwide discussion about utilization of carbon dioxide, the so-called dry gasification by means of CO 2 is also of great importance [8,9]. Also in some places Integrated Coal Gasification Combined Cycle power plants have been developed to reduce CO 2 emissions [6]. The presence of CO 2 can improve char conversion and decrease the volume of gasification residue [10].…”

Section: Introductionmentioning

confidence: 99%

“…In general, there are many publications concerning gasification kinetics of chars obtained from different types of coal [6,[21][22][23] or any types of biomass [4,[24][25][26]. However, according to our knowledge there are no publications on gasification kinetics of char derived from sewage sludge, except the study of Scott et al [26], who measured the rate of gasification by CO 2 of different chars, including char derived from sewage sludge.…”

Section: Introductionmentioning

confidence: 99%

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The kinetics of gasification of char derived from sewage sludge

Nowicki

Antecka

Bedyk

et al. 2010

J Therm Anal Calorim

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Gasification of char derived from sewage sludge was studied under different oxidizing atmospheres containing CO 2 , O 2 or H 2 O. The gasification tests were carried out in thermobalance at different temperatures and oxidizing reagent concentrations. The most efficient were the gaseous mixtures containing oxygen. The reaction took place at temperature 400-500°C, whilst in the case of CO 2 and steam much higher temperatures (700-900°C) were necessary to complete the conversion. Two rate models for gas-solid reaction were applied to describe the effect of char conversion on reaction rate. The shrinking core model for reaction-controlled regime was found to be the best for predicting the rate of char gasification in CO 2 and O 2 atmosphere. The experimental data for steam gasification of the char were fitted best by the first-order kinetics. The kinetic parameters estimated from the experimental data are in accordance with the literature for lignocellulosic char gasification and are the first published for sewage sludge char gasification.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The kinetics of gasification of char derived from sewage sludge

Nowicki

Antecka

Bedyk

et al. 2010

J Therm Anal Calorim

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“…15,16) However, it is difficult to comprehend the reactions within the composite in detail, because changes in the partial pressures of CO and CO2 are difficult to measure or evaluate accurately. On the other hand, the generation rates of CO and CO2 gases from the composite during heating can be determined by gas analysis.…”

Section: Analysis Methodsmentioning

confidence: 99%

Quantitative Analysis on Contribution of Direct Reduction of Iron Oxide in Carbon Composite

et al. 2013

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Many reactions such as the reduction of iron oxide, gasification of carbon, and so on occur simultaneously during heating of the iron oxide-carbon composites which attract attention as "microreactors". Solid carbon and CO gas react with iron oxide via direct and indirect reductions, respectively. The rate of indirect reduction has been studied extensively. On the other hand, there are very few reports on the quantitative analysis on the direct reduction due to analytical difficulties, although it is important to understand the total reduction mechanism in detail. In this study, the contribution of the direct reduction by solid carbon in the composite while heating at a constant rate under inert gas flow was quantitatively evaluated.The direct reduction from Fe2O3 to Fe3O4 proceeds at a low temperature during heating of the Fe2O3-graphite composite. When the reduction from Fe2O3 to Fe3O4 completes below 1 000°C, the contribution ratio of the direct reduction in the total reduction is approximately 45%. However, there is no effect of the particle size of the raw materials on the contribution ratio. Further, the contribution ratio of the direct reduction for the reduction from Fe3O4 to FeO is small.

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“…Several researchers [27][28][29][30][31] reported the temperature dependence of gasification reactivity. Kajitani et al [32] reported the gasification rate of coal chars with different particle size distributions in a high-temperature zone. Jayaraman and Gökalp [33][34][35] investigated the size effects of Indian and Turkish coal and char particles during pyrolysis and gasification using coupled thermogravimetric and mass spectrum analysis.…”

Section: Introductionmentioning

confidence: 99%

Thermogravimetric and evolved gas analyses of high ash Indian and Turkish coal pyrolysis and gasification

Jayaraman

Gökalp

2015

J Therm Anal Calorim

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High ash coals from India and Turkey are investigated in this study. A coupled thermogravimetric analyzer and mass spectrometer system is used for the thermal decomposition characterization of the coal samples and the identification of the volatiles evolved during the various reaction regions. Coal samples are heated in argon, air, oxygen, steam and blended gas mixtures at the temperature range from 25 to 1250°C. The experiments are performed to study the pyrolysis, combustion and gasification characteristics of typical Indian and Turkish high ash coals. Thermogravimetry and derivative thermogravimetry studies are applied to measure the conversion level and half-life time of the coals/chars during and after pyrolysis. The maximum mass loss occurs during the devolatilization stage of coals at the temperatures from 350 to 700°C, where O 2 , CO 2 , CO, H 2 and a small amount of CH 4 are released. Coal particles start to react with steam and produce CO 2 , CO and H 2 when the temperature is increased above 750°C. The gasification reactions are completed around 950°C in steam and steam blended ambience. The reactivity of high ash coal chars mainly depends on reagents' and surrounding gases concentration and also the reaction temperature. The results indicate that the size effect of the char particles is minimal at high gasification temperatures. Char gasification rates determined by TG techniques under isothermal conditions in different reagent flow rates and size effect contribute to enhance the knowledge on high ash coal thermal characterization and gasification and, therefore, to establish the optimum operational conditions for syngas production from high ash coals.

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CO gasification rate analysis of coal char in entrained flow coal gasifier

Cited by 257 publications

References 4 publications

The kinetics of gasification of char derived from sewage sludge

The kinetics of gasification of char derived from sewage sludge

Quantitative Analysis on Contribution of Direct Reduction of Iron Oxide in Carbon Composite

Thermogravimetric and evolved gas analyses of high ash Indian and Turkish coal pyrolysis and gasification

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