Impact of a CO₂-Enriched Gas on the Decarbonation of CaCO₃ and the Oxidation of Carbon in the Smoldering Process of Oil Shale Semicoke

Abstract

One way of recovering oil is to propagate a co-current feed smoldering front in oil shale. This can be performed either in situ or as an ex situ process. Smoldering in oil shale semicoke achieves both thermal valorization and carbon release. In both cases, two phenomena cause CO 2 formation and release: the oxidation of fixed carbon and the decarbonation of CaCO 3 . It is shown in this work that enriching the gas fed to the front with CO 2 significantly impacts both phenomena, potentially in a positive way: (i) the oxidation of fixed carbon to CO is encouraged, leading to the production of a richer gas and limiting the amount of CO 2 formed, and (ii) the decarbonation of CaCO 3 is limited, which also contributes to reducing the formation of CO 2 .

Heat losses in a smouldering system: The key role of non-uniform air flux

“…Here, the chemistry is only approximated, and some pyrolysis reactions evolving CO/CO2 may be embedded within the estimated % ̇'123 term. Nevertheless, the following analysis will be structured as if the net heat released from smouldering is from a an effective oxidation term, which aligns with previous smouldering research using similar fuels [46,55,83,84]. The fundamental chemistry steps within smouldering systems, even simple systems using pure carbon, GAC, or charcoal, presents an opportunity for future research [18].…”

Darcy Scale Modeling of Smoldering: Impact of Heat Loss

“…The stoichiometry of carbon consumption by the fed oxygen has been expressed in Eq. (2) by Sennoune et al (2012).…”

“…Understanding why a front is not flat is interesting for a man-controlled application because it underlies the front stability question. There are several reasons to explain the front shape change as already discussed in Sennoune et al (2012). The front velocity is basically controlled by the chemical reaction stoichiometry.…”

“…As the wave progresses, the endothermic drying of the medium is forced. If the medium contains carbonates, the endothermic decarbonation of the medium occurs when the temperature overpasses approximately 800°C (Sennoune et al, 2011).…”

Utilization of a CO2 Storage Material: Shape-Controlled Preparation of CaCO3 Microspheres

“…In recent years, carbon capture and storage (CCS) and CCU processes have been developed to control CO 2 emission and resource recovery [8][9][10][11][12]. In particular, the preparation of CaCO 3 via the chelation of CO 2 has been studied extensively because CaCO 3 , as one of the cheaper biological materials, has important applications in various fields [13][14][15][16][17][18][19][20]. There are four polymorphic phases that have been prepared as follows: calcite, aragonite, vaterite, and amorphous CaCO 3 (ACC) [21,22].…”