High ash coal pyrolysis at different heating rates to analyze its char structure, kinetics and evolved species

Jayaraman, Kandasamy; Gökalp, I.; Bostyn, Stéphane

doi:10.1016/j.jaap.2015.03.007

Cited by 56 publications

(24 citation statements)

References 55 publications

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“…features emphasize that the occurances of thermal lag increases along with the pyrolysis of heating rate of the coal, similar to the results reported in the literatures [28,35,[37][38][39].…”

Section: Coal-char Production Under High Heating Ratessupporting

confidence: 90%

“…Lua et al [42] also investigated that the growth of pores during initial pyrolysis is mainly due to the higher volatile matter release rate. Chars produced from high heating rate have already their pores open and exhibits high surface area [43,44], while the chars prepared from low heating rate possess a less-developed reactive surface and a narrower porous network, as presented in the SEM images ( Figure 7) and confirmed by BET surface area analysis [35,37]. Hence, the heating rate affects the coal devolatilisation rate, thereby it also influences the pore structure of the generated char particles and the probability of participation of active sites located in micropores.…”

Section: Coal-char Characterization Studiesmentioning

confidence: 75%

“…Owing to the variation in the ash and volatile content of the Turkish coals, larger particles have comparatively Gasification for Low-grade Feedstock higher content of residual char-mass, therefore, the DTG is quite low for 900 μm particles. This aspect can be elucidates by the fact that large particles exhibit more resistance to volatiles escape, in that way the secondary reactions rate increased and as a result of carbon deposition [37]. It can be seen that 800 μm particles shows the maximum DTG value of 80% when compared to the 50% value for 3 mm particles.…”

Section: Coal-char Production Under High Heating Ratesmentioning

confidence: 92%

“…The DTG results show that the maximum thermal degradation (DTG max ) of coal particles are shifted towards higher temperature as the heating rate increased. This is caused by differences in heat transfer and kinetic rates, thereby delaying sample decomposition [35,[37][38][39]. Hence, the heating rate mainly influences the primary pyrolysis stage of the coal, while the maximum weight loss rate and the corresponding temperature increases with heating rate.…”

Section: Coal-char Production Under High Heating Ratesmentioning

confidence: 99%

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Pyrolysis and Gasification Characteristics of High Ash Indian and Turkish Coals

Kandasamy¹,

Gökalp²

2018

Gasification for Low-Grade Feedstock

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Pyrolysis and gasification studies of Indian and Turkish high ash coal samples have been performed using coupled TGA-MS method. Coal samples were heated in the TGA apparatus in an argon, steam, CO 2 and blended mixtures of CO2 and steam in a temperature range from 25-1250°C with heating rates from 35 to 1000 K/min. Gas evolution measurements is performed using the mass spectrometry system. During the devolatilisation stage (350-700°C), the maximum mass loss has observed in which O 2 , CO 2 , CO, H 2 and small amount of hydrocarbon compounds are released. Char gasification is mainly influenced by operating conditions such as heating rate and reaction temperature and also the char production method, its physical structure and size and chemical composition of the char. The steam and CO 2 gasification rates of the chars are carried out at the temperatures of 850, 900, 950, and 1000°C. Three kinetic models are applied to describe the char conversion rates: volumetric model, grain model, and random pore model. The activation energy of Indian coal-char is varying from 122 to 177 kJ mol-1 under steam gasification and from 130 to 214 kJ mol-1 for CO 2 gasification. The activation energy for char-steam gasification is 156-173 kJ/ mol, whereas in the steam blended with CO 2 gasification, it ranges between 162 and 196 kJ/ mol for 3 mm particles. Similar trends are observed for the Arrhenius constant values for both sized particles.

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Section: Coal-char Production Under High Heating Ratessupporting

confidence: 90%

Section: Coal-char Characterization Studiesmentioning

confidence: 75%

Section: Coal-char Production Under High Heating Ratesmentioning

confidence: 92%

Section: Coal-char Production Under High Heating Ratesmentioning

confidence: 99%

See 2 more Smart Citations

Pyrolysis and Gasification Characteristics of High Ash Indian and Turkish Coals

Kandasamy¹,

Gökalp²

2018

Gasification for Low-Grade Feedstock

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“…The Friedman and FWO [23,39] model-free methods were applied in order to describe the pyrolysis reactive behavior of the raw lignite and the blends of lignite with oil shale chars. The TG experimental results obtained as mass loss versus temperature data, were converted to conversion degree (a) versus temperature profiles as Eq.…”

Section: Kinetic Analysismentioning

confidence: 99%

Catalytic characteristics of the pyrolysis of lignite over oil shale chars

2016

Applied Thermal Engineering

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Co‐pyrolysis of coal‐biomass: study on reaction kinetics and thermodynamics

Bhattacharyya

Shadangi

Mahanta

et al. 2021

Biofuels Bioprod Bioref

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This investigation reports a kinetic and thermodynamic study (using the Kissinger–Akahira–Sunose method) of coal–sawdust co‐pyrolysis calculated beyond the evaporation zone. The effects of co‐pyrolysis on activation energy (E a) and thermodynamic parameters are compared with those of individual pyrolysis. This study clarifies the effect of biomass on the thermal stability of coal during co‐pyrolysis. The co‐pyrolysis of sawdust with coal helps increase the rate of thermal degradation in the low‐temperature degradation zone by reducing the activation energy and Gibbs free energy. The alternation of the value of E a from positive to negative occurs beyond the active pyrolytic zone. The overall E a of coal pyrolysis (196 kJ mol−1) shows a value higher than that for the co‐pyrolysis of coal and sawdust (100.632 kJ mol−1). Similarly, the Gibbs free energy and enthalpy for coal also show higher values associated with co‐pyrolysis. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd

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High ash coal pyrolysis at different heating rates to analyze its char structure, kinetics and evolved species

Cited by 56 publications

References 55 publications

Pyrolysis and Gasification Characteristics of High Ash Indian and Turkish Coals

Pyrolysis and Gasification Characteristics of High Ash Indian and Turkish Coals

Catalytic characteristics of the pyrolysis of lignite over oil shale chars

Co‐pyrolysis of coal‐biomass: study on reaction kinetics and thermodynamics

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