On the alternating physicochemical characteristics of Colombian coal during pyrolysis

Wütscher, Annika; Wedler, Carsten; Seibel, Christopher; Hiltrop, Dennis; Fieback, Tobias

doi:10.1016/j.jaap.2017.01.007

Cited by 10 publications

(5 citation statements)

References 21 publications

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“…Volatiles released may burn near the vicinity of the particles surface in the presence of oxygen. Generally, the composition of the volatiles released during devolatilization of coal depends on the composition of the parent coal, operating conditions such as temperature, reactor type, and particle size. − CH 4 , CO, CO 2 , H 2 O, H 2 , and C 2 H 6 and traces of other higher hydrocarbons are the main gaseous constituents in the evolved volatiles . In the present study, however, the individual components have not been considered, and the evolution of total volatiles is estimated at different time instants and with ΔH vc , the average value of heat of combustion for the volatiles as −44 × 10 6 J/kg …”

Section: Results and Discussionmentioning

confidence: 98%

Devolatilization and Combustion of Coarse-Sized Coal Particles in Oxy–Fuel Conditions: Experimental and Modeling Studies

et al. 2018

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A generalized unsteady-state kinetic model, coupled with all modes of heat transfer, was developed to describe the combined coal devolatilization and the subsequent combustion of the residual char under oxy−fuel condition in both O 2 −CO 2 and O 2 −N 2 environments. Experiments were conducted to validate the model, which was also found to predict the experimental data published in the literature well. The effect of coal particle diameter, temperature of the reactor, and oxygen concentration on devolatilization time was investigated. Peaks in devolatilization and char combustion rates and particle center temperature were studied, and the effect of different parameters assessed. Higher reaction time was observed in an O 2 −CO 2 environment compared to that in an O 2 −N 2 environment due to lower particle temperatures resulting from endothermic gasification reaction and the difference in thermo-physical properties. Simulation studies were carried out to generate temperature, carbon, O 2 , CO, and CO 2 contours to understand the char combustion reaction mechanism. The reaction started at the external surface of the particle, following unreacted shrinking core model with two zones; the solid product layer and the unreacted shrinking core, separated by a thin reaction front. Gradually, the reaction front thickness increases, leading to the shrinking reactive core model, consisting of three zones: completely reacted ash layer, partially burnt reacting char called reaction zone, and unreacted zone or slightly reacted char core. At the outset, O 2 cannot penetrate into the particle and CO produced near the surface diffuses out to the boundary layer, forming a thin flame. Subsequently, O 2 diffuses through porous ash layer into the char, and CO burns within the pores, with hardly any CO detected in the boundary layer as the particle temperature increases.

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Section: Results and Discussionmentioning

confidence: 98%

Devolatilization and Combustion of Coarse-Sized Coal Particles in Oxy–Fuel Conditions: Experimental and Modeling Studies

et al. 2018

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“…For higher temperatures, the structure changes significantly indicated by a decrease of the CC and CO bands and an increase of the aromatic out-of-plane bands. In addition, the aliphatic C–H vibrations corresponding to the band at around 2920 cm –1 disappear with increasing pyrolysis temperature. , Simultaneously, the intensity of the band at 3045 cm –1 assigned to aromatic C–H vibrations , rises.…”

Section: Resultsmentioning

confidence: 99%

“…In addition, the aliphatic C−H vibrations corresponding to the band at around 2920 cm −1 disappear with increasing pyrolysis temperature. 30,31 Simultaneously, the intensity of the band at 3045 cm −1 assigned to aromatic C−H vibrations 31,33 rises.…”

Section: Introductionmentioning

confidence: 91%

“…Also, a broad band in the range from 3600 to 3200 cm −1 is visible, originating from O−H stretching vibrations. 33 Bands between 1470 and 1370 cm −1 are mainly due to different CH vibration modes, 27,29,30 and the ones between 1200 and 1000 cm −1 indicate the presence of C−O groups. 27,30,32 Up to a pyrolysis temperature of 300 °C, changes in the recorded spectra are minor.…”

Section: Introductionmentioning

confidence: 99%

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Tuning the Properties of Iron-Doped Porous Graphitic Carbon Synthesized by Hydrothermal Carbonization of Cellulose and Subsequent Pyrolysis

et al. 2019

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The applied pyrolysis temperature was found to strongly affect composition, structure, and oxidation behavior of pure and iron oxide nanoparticle (NP)-loaded carbon materials originating from hydrothermal carbonization (HTC) of cellulose. A strong loss of functional groups during pyrolysis at temperatures beyond 300 °C of the HTC-derived hydrochars was observed, resulting in an increase of the carbon content up to 95 wt% for the carbon materials pyrolyzed at 800 °C and an increase of the specific surface area with a maximum of 520 m 2 g –1 at a pyrolysis temperature of 600 °C. Devolatilization mainly took place in the range from 300 to 500 °C, releasing light pyrolysis gases such as CO, CO 2 , H 2 O and larger oxygen-containing molecules up to C 11 . The presence of iron oxide NPs lowered the specific surface areas by about 200 m 2 g –1 and resulted in the formation of mesopores. For the iron oxide-containing composites pyrolyzed up to 500 °C, the oxidation temperature was decreased by about 100 °C, indicating tight contact between the iron oxide NPs and the carbon matrix. For higher pyrolysis temperatures, this catalytic effect of iron oxide on carbon oxidation vanished due to carbothermal reduction to iron and iron carbide, which, however, catalyzed the graphitization of the carbon matrix. Thus, the well-controlled two-step synthesis based on a biomass-derived precursor yielded stably embedded iron NPs in a corrosion-resistant graphitic carbon matrix.

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“…With the development of people's awareness of the rational use of coal resources, the Chinese government has continuously improved environmental protection standards, improved relevant laws and regulations, and developed and utilized various new types of clean energy. However, as far as my country's current situation is concerned, coal resources dominate the energy structure the status cannot be fundamentally changed within a period of time [3][4]. In recent years, smog has occurred frequently in many places in my country, and one of the main culprits is the burning of coal [5][6].…”

Section: Introductionmentioning

confidence: 99%

Coupling Oil Increase by Coal Liquefaction Residue Pyrolysis and Coal Pyrolysis Depolymerization Based on Big Data

Zhang

Liu

et al. 2022

J. Phys.: Conf. Ser.

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With the continuous improvement of big data technology, my country’s coal liquefaction technology has also continued to mature, maintaining a stable industrial development. Traditional coal pyrolysis technology for tar production with the purpose of increasing tar production, such as coal hydropyrolysis, has problems such as high cost of pure hydrogen atmosphere and complex process and equipment operations, which severely restrict its industrial operation process. Based on this, this paper proposes a new technology of coal pyrolysis and depolymerization coupled with oil increase by using hydrogen precipitated by the condensation polymerization reaction at relatively high temperature under big data technology to study the effect of this process on coal pyrolysis for oil production. Experiments show that at 700°C, the tar yield reaches 21.5wt.%, which is 6% and 7% higher than the pyrolysis tar yield under the same conditions under hydrogen and nitrogen atmospheres. At 600°C, the methane aromatization reaction is relatively weak, and it can be seen that the tar yield is only slightly higher than that under hydrogen and nitrogen atmospheres. As the temperature of the methane anaerobic aromatization reaction increases, the equilibrium conversion rate increases accordingly. Therefore, as the reaction temperature increases, the tar yield also begins to increase.

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On the alternating physicochemical characteristics of Colombian coal during pyrolysis

Cited by 10 publications

References 21 publications

Devolatilization and Combustion of Coarse-Sized Coal Particles in Oxy–Fuel Conditions: Experimental and Modeling Studies

Devolatilization and Combustion of Coarse-Sized Coal Particles in Oxy–Fuel Conditions: Experimental and Modeling Studies

Tuning the Properties of Iron-Doped Porous Graphitic Carbon Synthesized by Hydrothermal Carbonization of Cellulose and Subsequent Pyrolysis

Coupling Oil Increase by Coal Liquefaction Residue Pyrolysis and Coal Pyrolysis Depolymerization Based on Big Data

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