Pyrolysis kinetics of oil shale from northeast China: Implications from thermogravimetric and Rock–Eval experiments

Han, Hwataik; Zhong, Ningning; Huang, Can; Zhang, Wei

doi:10.1016/j.fuel.2015.07.052

Cited by 31 publications

(9 citation statements)

References 47 publications

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“…The average activation energy corresponding to the OM pyrolysis process of CK oil shale is estimated to be 211.5 ± 4.7 kJ mol −1 . This value is consistent with the energies obtained during the type I kerogen pyrolysis of the Green River, Colorado and Huadian oil shales which were evaluated to be 201, 219.4 and 231 kJ mol −1 , respectively (Campbell et al 1978;Han et al 2015;Maaten et al 2017).…”

Section: Activation Energy Determinationsupporting

confidence: 89%

Type I kerogen-rich oil shale from the Democratic Republic of the Congo: mineralogical description and pyrolysis kinetics

et al. 2019

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The Democratic Republic of the Congo holds important reserves of oil shale which is still under geological status. Herein, the characterization and pyrolysis kinetics of type I kerogen-rich oil shale of the western Central Kongo (CK) were investigated. X-ray diffraction, Fourier-transform infrared spectroscopy and thermal analysis (TG/DTA) showed that CK oil shale exhibits a siliceous mineral matrix with a consistent organic matter rich in aliphatic chains. The pyrolysis behavior of kerogen revealed the presence of a single mass loss between 300 and 550 °C, estimated at 12.5% and attributed to the oil production stage. Non-isothermal kinetics was performed by determining the activation energy using the iterative isoconversional model-free methods and exhibits a constant value with E = 211.5 ± 4.7 kJ mol −1. The most probable kinetic model describing the kerogen pyrolysis mechanism was obtained using the Coats-Redfern and Arrhenius plot methods. The results showed a unique kinetic triplet confirming the nature of kerogen, predominantly type I and reinforcing the previously reported geochemical characteristics of the CK oil shale. Besides, the calculation of thermodynamic parameters (ΔH*, ΔS* and ΔG*) corresponding to the pyrolysis of type I kerogen revealed that the process is non-spontaneous, in agreement with DTA experiments.

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Section: Activation Energy Determinationsupporting

confidence: 89%

Type I kerogen-rich oil shale from the Democratic Republic of the Congo: mineralogical description and pyrolysis kinetics

et al. 2019

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“…A thermocouple was used to measure the temperature of the sample center. For each test, 50 g of oil shale was loaded into the retorting reactor, which was then slowly heated from room temperature to the pyrolysis temperature at a heating rate of 2 °C·min –1 to guarantee uniform temperature distribution in the sample. , Upon reaching the temperature, the reactor was quickly cooled to room temperature, and then the gas, shale oil, and semicoke were weighed. Thermal bitumen was extracted from the semicoke by using the Soxhlet extractor with chloroform solvent (CHCl 3 ) at 65–70 °C for 48 h. The chloroform solution was finally evaporated to obtain thermal bitumen and then maintained in a cold storage for further analysis (Figure ).…”

Section: Methodsmentioning

confidence: 99%

Characteristics of Thermal Bitumen Structure as the Pyrolysis Intermediate of Longkou Oil Shale

Jian

et al. 2017

Energy Fuels

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The effects of pyrolysis temperature on the structure of thermal bitumen as the pyrolysis intermediate of Longkou oil shale are investigated through electron paramagnetic resonance spectroscopy, Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, gas chromatography–mass spectrometry (GC-MS), and X-ray photoelectron spectroscopy (XPS). Results indicate that the free radical concentration of thermal bitumen increases at a maximum temperature of 410 °C and then decreases between 410 and 450 °C. Moreover, the g factors of thermal bitumen are slightly higher than 2 and decrease with increasing temperature because of the aromatization of saturates and decarboxylation. FTIR analysis indicates that decarboxylation is completed before the temperature reaches 370 °C. NMR analysis shows that aliphatic and aromatic compounds comprise more than 80% and 15–16% thermal bitumen, respectively. During pyrolysis, the fraction of aliphatic compounds, branched alkane, and the average methylene chain length decrease because of secondary cracking, and the C–C bond at the branch chain is easily cracked into gas and light oil.

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“…To obtain thermal bitumen, 30 g of oil shale sample was loaded into the retort. Then, the reactor was slowly heated from room temperature to the pyrolysis temperature at a heating rate of 2 °C/min to guarantee that the whole sample was evenly heated. , When the final temperature was reached, the reactor was rapidly cooled to room temperature. The thermal bitumen was then extracted from semi-coke by a Soxhlet extractor with chloroform (CHCl 3 ) as the solvent at 65–70 °C for 48 h. The chloroform solution was finally evaporated in a rotary evaporator to obtain thermal bitumen, which was then stored in cold storage for further analysis.…”

Section: Experimental Sectionmentioning

confidence: 99%

Characteristics of Estonian Oil Shale Kerogen and Its Pyrolysates with Thermal Bitumen as a Pyrolytic Intermediate

Jian

et al. 2017

Energy Fuels

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Preparation and collection of thermal bitumen, a pyrolytic intermediate, are key factors in elucidating the mechanism of oil shale pyrolysis. Electron paramagnetic resonance (EPR), gas chromatography, Fourier transform infrared spectrophotometry, nuclear magnetic resonance (NMR) spectrometry, distortionless enhancement by polarization transfer (DEPT), and X-ray photoelectron spectroscopy were employed to investigate the thermochemical transformation in oil shale pyrolysis. Results showed that thermal bitumen was continuously generated and decomposed during the pyrolysis process. The maximum yield of thermal bitumen at 380 °C was 11.17%. EPR analysis showed that the g factor of kerogen and the pyrolysates was slightly higher than 2 and increased as pyrolysis progressed because of the aromatization of saturates and decarboxylation. CO2 and CO were mainly generated at temperatures lower than 340 °C, and less was obtained in the subsequent pyrolysis process. In contrast, C2–C5 organic gases were mainly generated at temperatures higher than 340 °C. NMR and DEPT analyses indicated that kerogen, thermal bitumen, and shale oil were mainly composed of aliphatic structures. During the pyrolysis process, aliphatic structures were constantly transformed into aromatic compounds, which were easily retained in shale oil and semi-coke. Pyrrolic, pyridinic, and quaternary compounds constituted 80% of the nitrogen compounds in kerogen and the pyrolysates. The sulfoxide content of thermal bitumen and semi-coke was considerably higher than that of kerogen, indicating that sulfoxide compounds present better thermostability during the pyrolysis process.

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Pyrolysis kinetics of oil shale from northeast China: Implications from thermogravimetric and Rock–Eval experiments

Cited by 31 publications

References 47 publications

Type I kerogen-rich oil shale from the Democratic Republic of the Congo: mineralogical description and pyrolysis kinetics

Type I kerogen-rich oil shale from the Democratic Republic of the Congo: mineralogical description and pyrolysis kinetics

Characteristics of Thermal Bitumen Structure as the Pyrolysis Intermediate of Longkou Oil Shale

Characteristics of Estonian Oil Shale Kerogen and Its Pyrolysates with Thermal Bitumen as a Pyrolytic Intermediate

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