Omodeo-Sale S.,French Institute of Petroleum |
Deschamps R.,French Institute of Petroleum |
Michel P.,French Institute of Petroleum |
Chauveau B.,French Institute of Petroleum |
Suarez-Ruiz I.,INCAR CSIC
International Journal of Coal Geology | Year: 2017
This work analyzes the distribution of coal-bearing strata in the stratigraphic framework of the Mannville Group (Lower Cretaceous, Western Canada Sedimentary Basin). In the 3rd-order depositional sequence the maximum abundance of coal layers is found in the highstand system tracts (HST), whereas in the 4th-order eustatic sequences, coal deposits distribute similarly in the highstand and transgressive system tracts (TST). These trends have been related to the variation of accommodation space in the basin, which mostly influence the occurrence of favorable conditions for organic matter preservation. Petrographic analyses permit to identify variation in the coal layers composition and to relate them with the stratigraphic dynamic of the basin. The HST is characterized by a low subsidence rate, which induces low levels of the groundwater table, favoring dry conditions in the peat. By consequence, in the HST a higher abundance of inertinite maceral group is observed than in the TST. On the other hand, the TST is characterized by higher subsidence rates, thus more stable groundwater table levels, promoting the organic matter preservation. Therefore, in the TST a higher content of vitrinite and liptinite maceral groups is observed. In correspondence of the maximum flooding surface (MFS), the peat is frequently flooded, with the consequent dilution of the organic matter with terrigeneous sediment, forming carbonaceous shales deposits. By the analysis of the organic matter composition, seven depositional environments for coal were identified, located at different distance from the coast line. Each depositional environment is characterized by a specific organo-facies association, which is the reflex of different environmental conditions in the peat, in terms of water table level, type of vegetation and hydrodynamic processes. The vertical superimposition in a coal package of different depositional environments has been related to high order climatic cyclicity (5th-order transgressive and regressive cycles), which controls the groundwater table fluctuations. © 2017 Elsevier B.V.
Staiti P.,CNR Institute of Advanced Energy Technologies Nicola Giordano |
Arenillas A.,INCAR CSIC |
Lufrano F.,CNR Institute of Advanced Energy Technologies Nicola Giordano |
Menendez J.A.,INCAR CSIC
Journal of Power Sources | Year: 2012
An ultracapacitor (UCap) based on carbon xerogel electrodes and sodium sulfate electrolyte was investigated in the voltage range between 0 and 1.8 V. Notwithstanding the high value of maximum voltage (1.8 V) the UCap exhibited excellent stability during 20000 of cycling test. Moreover, the achievement of this high voltage made possible to obtain high value of specific energy. The stability was possible because the potential limits of electrode-electrolyte decomposition at positive and negative electrodes were never achieved. This is because an asymmetric UCap with different amounts of carbon xerogel in the electrodes was used. The UCap with the carbon xerogel of BET specific surface area of 3100 m 2 g -1 demonstrated a specific energy of 17.5 Wh kg -1 and a specific capacitance of 156 F g -1 and, retained 91% of initial capacitance after 20000 cycles of duration test. © 2012 Elsevier B.V. All rights reserved.
Bermudez J.M.,INCAR CSIC |
Francavilla M.,University of Foggia |
Francavilla M.,National Research Council Italy |
Calvo E.G.,INCAR CSIC |
And 4 more authors.
RSC Advances | Year: 2014
An efficient methodology based on low temperature microwave-induced pyrolysis has been developed for syngas production from macroalgae. The protocol provided unprecedented hydrogen production, with switchable H2/CO ratios depending on pyrolysis conditions which were found to remarkably improve conventional pyrolysis experiments even at significantly higher temperatures (400 vs. 800 °C). Arcing effects under microwave irradiation, which result in an interesting observed pseudo-catalytic effect promoted by the metal oxides contained in macroalgae, seem to account for the improved results. © the Partner Organisations 2014.