Simultaneous thermogravimetric–mass spectrometric study on the pyrolysis behaviour of different rank coals

Arenillas, A.; Rubiera, F.; Pís, J.J.

doi:10.1016/s0165-2370(99)00024-8

Cited by 198 publications

(142 citation statements)

References 29 publications

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“…The rate of mass loss was recorded as a function of temperature or time, and the different compounds evolved during pyrolysis were analysed by means of a mass spectrometer (MS), linked to the TG. The optimisation of this on-line equipment has been described elsewhere [4]. The results obtained at different heating rates were examined and different models were applied in order to obtain the kinetic constants for the 50ºC min -1 run.…”

Section: Methodsmentioning

confidence: 99%

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A comparison of different methods for predicting coal devolatilisation kinetics

Arenillas

Rubiera

Pevida

et al. 2001

Journal of Analytical and Applied Pyrolysis

132

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Knowledge of the coal devolatilisation rate is of great importance because it exerts a marked effect on the overall combustion behaviour. Different approaches can be used to obtain the kinetics of the complex devolatilisation process. The simplest are empirical and employ global kinetics, where the Arrhenius expression is used to correlate rates of mass loss with temperature. In this study a high volatile bituminous coal was devolatilised at four different heating rates in a thermogravimetric analyser (TG) linked to a mass spectrometer (MS). As a first approach, the Arrhenius kinetic parameters (k and A) were calculated from the experimental results, assuming a single step process.Another approach is the distributed-activation energy model, which is more complex due to the assumption that devolatilisation occurs through several first-order reactions, which occur simultaneously. Recent advances in the understanding of coal structure have led to more fundamental approaches for modelling devolatilisation behaviour, such as network models. These are based on a physico-chemical description of coal structure.In the present study the FG-DVC (Functional Group-Depolymerisation, Vaporisation and Crosslinking) computer code was used as the network model and the FG-DVC predicted evolution of volatile compounds was compared with the experimental results.In addition, the predicted rate of mass loss from the FG-DVC model was used to obtain a third devolatilisation kinetic approach. The three methods were compared and discussed, with the experimental results as a reference.

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Section: Methodsmentioning

confidence: 99%

“…These fragments will be released as tar if they are small enough to vaporise and be transported out of the char particle. Functional groups also decompose to release gases, mainly CO 2 , light aliphatics, CH 4 and H 2 O.…”

Section: Introductionmentioning

confidence: 99%

A comparison of different methods for predicting coal devolatilisation kinetics

Arenillas

Rubiera

Pevida

et al. 2001

Journal of Analytical and Applied Pyrolysis

132

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“…The ion signals given by the spectrometer were normalised by the total intensity and the sample mass to make the results internally consistent. The repeatability of the profiles was excellent, and a statistic study of the integrated peak area values was performed, using Student`s t-test, giving a very good precision [33]. In this way, it was possible to compare the same m/z signals for different samples and perform a semi-quantitative analysis of the evolved gaseous compounds.…”

Section: Methodsmentioning

confidence: 99%

“…initial It has to be taken into account that in this work no calibration was performed to quantify the amount of each volatile species. Nevertheless, the ion signals given by the spectrometer were normalised by the total intensity and the sample mass to make the results internally consistent [33]. In this way, it was possible to compare the same m/z signals for different samples; in addition the peak area from the different species profiles can be calculated, in order to provide a semi-quantitative analysis.…”

Section: Evaluation Of Ms Response Factorsmentioning

confidence: 99%

Thermogravimetric–mass spectrometric study on the evolution of nitrogen compounds during coal devolatilisation

Arenillas

Rubiera

Pevida

et al. 2002

Journal of Analytical and Applied Pyrolysis

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Emissions of nitrogen oxides during coal combustion are a major environmental problem. The chemically bound nitrogen in fuel accounts for up to 80% of total NOx emissions. In this respect, fundamental studies are needed to clarify the mechanisms and to identify the different species that are precursors in the formation of the NOx. Mass spectrometry (MS) has been used for decades as a successful technique in evolved gas analysis. However, MS is normally used to identify typical volatile compounds formed during coal pyrolysis (i.e. H 2 , CH 4 , CO,

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“…Arenillas et al [23] performed the optimization of TG-MS coupling and developed a normalization procedure allowing a semiquantitative comparison between pyrolysis gases from various rank coals. Nali et al [12] performed gas chromatography and mass spectrometry studies for the pyrolysis of various Polish and US lignites.…”

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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Simultaneous thermogravimetric–mass spectrometric study on the pyrolysis behaviour of different rank coals

Cited by 198 publications

References 29 publications

A comparison of different methods for predicting coal devolatilisation kinetics

A comparison of different methods for predicting coal devolatilisation kinetics

Thermogravimetric–mass spectrometric study on the evolution of nitrogen compounds during coal devolatilisation

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

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