The assessment of maturation changes of humic coal organic matter - Insights from closed-system pyrolysis experiments
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2016
Authors
Vuković, Nikola
Životić, Dragana

Mendonca Filho, Joao Graciano

Kravić-Stevović, Tamara

Hamor-Vido, Maria
Mendonca, Joalice de Oliveira

Stojanović, Ksenija

Article (Published version)

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The artificial maturation changes of the humic coal organic matter (OM) from late diagenesis to the semianthracite stage of coalification were investigated using the closed-system pyrolysis. Two extracted coal samples, a subbituminous coal 26C (with a random vitrinite reflectance Rr = 0.42%) and a high volatile bituminous coal 30C (Rr = 0.56%), were pyrolysed during 4 hat two different temperatures, 250 degrees C and 400 degrees C. The applied petrographic and organic geochemical analyses showed that the humic coal OM is sensitive to the artificial thermal stress. A good correlation between the changes in petrographic characteristics and the derived liquid products was observed. The contents of all vitrinite macerals, as well as total vitrinite, increased during the thermal maturation. The abundance of liptinite macerals decreased during the maturation and they practically disappeared after 4 h of the pyrolysis at 400 degrees C. The total inertinite contents increased after the pyrolys...is at 250 degrees C, yet to be decreased after the pyrolysis at 400 degrees C. The content of organic carbon increased from coals to the solid residues at 400 degrees C, whereas the contents of total hydrogen and sulphur decreased. The yields of gases, liquid products and solid residues at respective temperatures were very similar for both coals, regardless of the rank. As expected, the pyrolysis at 400 degrees C gave higher gas and liquid yields than at 250 degrees C. Regarding the liquid pyrolysates, more pronounced changes were observed in the distribution of aromatic compounds than in saturated biomarkers. The distributions of the aromatics indicate that apart from cracking and isomerisation (the formation of thermodynamically more stable isomers), the reactions of dehydrocyclization, condensation (the formation of more stable conjugated systems) and aromatization, as well as reactions involving H2S, elemental sulphur and reactive phenyl radicals released during the pyrolysis, also play an important role. It was shown that bentonitic clay plays a more important role in the subsequent aromatization of the OM than the initial maturity of the coal OM. n-Alkane parameters were useful at lower maturities (up to similar to 0.75% Rr), whereas sterane, naphthalene and phenanthrene maturity ratios are applicable at higher maturities (>0.75% Rr). Hopane parameters showed variable sensitivities over the investigated maturity range (0.5-1.8% Rr). The most sensitive maturity parameters in the wide range of the humic OM maturity (0.5-1.8% Rr) are vitrinite reflectance, phenylnaphthalene ratio, methylchrysene index 2 and a parameter proposed in this study, based on the distribution of methylfluorenes (MF): (2- + 3-MF) / (1- + 4-MF). Generally, maturity parameters based solely on the isomerisation reactions of alkylaromatics, which do not include alkylation/dealkylation processes, are more appropriate for the humic OM, particularly at higher maturities.
Keywords:
Pyrolysis / Maturity / Macerals / Humic coal organic matter / Biomarkers / Aromatic compoundsSource:
International Journal of Coal Geology, 2016, 154-155, 213-239Publisher:
- Elsevier, Amsterdam
Funding / projects:
- Geochemical investigations of sedimentary rocks - fossil fuels and environmental pollutants (RS-176006)
DOI: 10.1016/j.coal.2016.01.007
ISSN: 0166-5162
WoS: 000371554300018
Scopus: 2-s2.0-84955238090
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Institut za tehnologiju nuklearnih i drugih mineralnih sirovinaTY - JOUR AU - Vuković, Nikola AU - Životić, Dragana AU - Mendonca Filho, Joao Graciano AU - Kravić-Stevović, Tamara AU - Hamor-Vido, Maria AU - Mendonca, Joalice de Oliveira AU - Stojanović, Ksenija PY - 2016 UR - https://ritnms.itnms.ac.rs/handle/123456789/414 AB - The artificial maturation changes of the humic coal organic matter (OM) from late diagenesis to the semianthracite stage of coalification were investigated using the closed-system pyrolysis. Two extracted coal samples, a subbituminous coal 26C (with a random vitrinite reflectance Rr = 0.42%) and a high volatile bituminous coal 30C (Rr = 0.56%), were pyrolysed during 4 hat two different temperatures, 250 degrees C and 400 degrees C. The applied petrographic and organic geochemical analyses showed that the humic coal OM is sensitive to the artificial thermal stress. A good correlation between the changes in petrographic characteristics and the derived liquid products was observed. The contents of all vitrinite macerals, as well as total vitrinite, increased during the thermal maturation. The abundance of liptinite macerals decreased during the maturation and they practically disappeared after 4 h of the pyrolysis at 400 degrees C. The total inertinite contents increased after the pyrolysis at 250 degrees C, yet to be decreased after the pyrolysis at 400 degrees C. The content of organic carbon increased from coals to the solid residues at 400 degrees C, whereas the contents of total hydrogen and sulphur decreased. The yields of gases, liquid products and solid residues at respective temperatures were very similar for both coals, regardless of the rank. As expected, the pyrolysis at 400 degrees C gave higher gas and liquid yields than at 250 degrees C. Regarding the liquid pyrolysates, more pronounced changes were observed in the distribution of aromatic compounds than in saturated biomarkers. The distributions of the aromatics indicate that apart from cracking and isomerisation (the formation of thermodynamically more stable isomers), the reactions of dehydrocyclization, condensation (the formation of more stable conjugated systems) and aromatization, as well as reactions involving H2S, elemental sulphur and reactive phenyl radicals released during the pyrolysis, also play an important role. It was shown that bentonitic clay plays a more important role in the subsequent aromatization of the OM than the initial maturity of the coal OM. n-Alkane parameters were useful at lower maturities (up to similar to 0.75% Rr), whereas sterane, naphthalene and phenanthrene maturity ratios are applicable at higher maturities (>0.75% Rr). Hopane parameters showed variable sensitivities over the investigated maturity range (0.5-1.8% Rr). The most sensitive maturity parameters in the wide range of the humic OM maturity (0.5-1.8% Rr) are vitrinite reflectance, phenylnaphthalene ratio, methylchrysene index 2 and a parameter proposed in this study, based on the distribution of methylfluorenes (MF): (2- + 3-MF) / (1- + 4-MF). Generally, maturity parameters based solely on the isomerisation reactions of alkylaromatics, which do not include alkylation/dealkylation processes, are more appropriate for the humic OM, particularly at higher maturities. PB - Elsevier, Amsterdam T2 - International Journal of Coal Geology T1 - The assessment of maturation changes of humic coal organic matter - Insights from closed-system pyrolysis experiments EP - 239 SP - 213 VL - 154-155 DO - 10.1016/j.coal.2016.01.007 UR - conv_752 ER -
@article{ author = "Vuković, Nikola and Životić, Dragana and Mendonca Filho, Joao Graciano and Kravić-Stevović, Tamara and Hamor-Vido, Maria and Mendonca, Joalice de Oliveira and Stojanović, Ksenija", year = "2016", abstract = "The artificial maturation changes of the humic coal organic matter (OM) from late diagenesis to the semianthracite stage of coalification were investigated using the closed-system pyrolysis. Two extracted coal samples, a subbituminous coal 26C (with a random vitrinite reflectance Rr = 0.42%) and a high volatile bituminous coal 30C (Rr = 0.56%), were pyrolysed during 4 hat two different temperatures, 250 degrees C and 400 degrees C. The applied petrographic and organic geochemical analyses showed that the humic coal OM is sensitive to the artificial thermal stress. A good correlation between the changes in petrographic characteristics and the derived liquid products was observed. The contents of all vitrinite macerals, as well as total vitrinite, increased during the thermal maturation. The abundance of liptinite macerals decreased during the maturation and they practically disappeared after 4 h of the pyrolysis at 400 degrees C. The total inertinite contents increased after the pyrolysis at 250 degrees C, yet to be decreased after the pyrolysis at 400 degrees C. The content of organic carbon increased from coals to the solid residues at 400 degrees C, whereas the contents of total hydrogen and sulphur decreased. The yields of gases, liquid products and solid residues at respective temperatures were very similar for both coals, regardless of the rank. As expected, the pyrolysis at 400 degrees C gave higher gas and liquid yields than at 250 degrees C. Regarding the liquid pyrolysates, more pronounced changes were observed in the distribution of aromatic compounds than in saturated biomarkers. The distributions of the aromatics indicate that apart from cracking and isomerisation (the formation of thermodynamically more stable isomers), the reactions of dehydrocyclization, condensation (the formation of more stable conjugated systems) and aromatization, as well as reactions involving H2S, elemental sulphur and reactive phenyl radicals released during the pyrolysis, also play an important role. It was shown that bentonitic clay plays a more important role in the subsequent aromatization of the OM than the initial maturity of the coal OM. n-Alkane parameters were useful at lower maturities (up to similar to 0.75% Rr), whereas sterane, naphthalene and phenanthrene maturity ratios are applicable at higher maturities (>0.75% Rr). Hopane parameters showed variable sensitivities over the investigated maturity range (0.5-1.8% Rr). The most sensitive maturity parameters in the wide range of the humic OM maturity (0.5-1.8% Rr) are vitrinite reflectance, phenylnaphthalene ratio, methylchrysene index 2 and a parameter proposed in this study, based on the distribution of methylfluorenes (MF): (2- + 3-MF) / (1- + 4-MF). Generally, maturity parameters based solely on the isomerisation reactions of alkylaromatics, which do not include alkylation/dealkylation processes, are more appropriate for the humic OM, particularly at higher maturities.", publisher = "Elsevier, Amsterdam", journal = "International Journal of Coal Geology", title = "The assessment of maturation changes of humic coal organic matter - Insights from closed-system pyrolysis experiments", pages = "239-213", volume = "154-155", doi = "10.1016/j.coal.2016.01.007", url = "conv_752" }
Vuković, N., Životić, D., Mendonca Filho, J. G., Kravić-Stevović, T., Hamor-Vido, M., Mendonca, J. d. O.,& Stojanović, K.. (2016). The assessment of maturation changes of humic coal organic matter - Insights from closed-system pyrolysis experiments. in International Journal of Coal Geology Elsevier, Amsterdam., 154-155, 213-239. https://doi.org/10.1016/j.coal.2016.01.007 conv_752
Vuković N, Životić D, Mendonca Filho JG, Kravić-Stevović T, Hamor-Vido M, Mendonca JDO, Stojanović K. The assessment of maturation changes of humic coal organic matter - Insights from closed-system pyrolysis experiments. in International Journal of Coal Geology. 2016;154-155:213-239. doi:10.1016/j.coal.2016.01.007 conv_752 .
Vuković, Nikola, Životić, Dragana, Mendonca Filho, Joao Graciano, Kravić-Stevović, Tamara, Hamor-Vido, Maria, Mendonca, Joalice de Oliveira, Stojanović, Ksenija, "The assessment of maturation changes of humic coal organic matter - Insights from closed-system pyrolysis experiments" in International Journal of Coal Geology, 154-155 (2016):213-239, https://doi.org/10.1016/j.coal.2016.01.007 ., conv_752 .