In situ gasification Chemical-Looping Combustion of coal using limestone as oxygen carrier precursor and sulphur sorbent

Abstract

In-situ Gasification Chemical-Looping Combustion (iG-CLC) burning coal is achieving a great interest due to the possibility of using low cost oxygen carriers such as CaSO 4. The Limestone Chemical Looping Combustion process (LCL-C TM) registered by Alstom Power Inc. proposes the use of a continuous CaCO 3 feeding together with coal to produce CaSO 4 as an oxygen carrier via sulphur retention. The operation is similar to what happens in a circulating fluidized bed boiler burning coal. In the present research work, the study of thermodynamic equilibrium limitations together with mass and enthalpy balances have been carried out for a CLC system in order to investigate whether the LCL-C TM process is a promising and energy efficient option to carry out the coal combustion with CO 2 capture and in-situ desulphurisation. So, no limitations were found to transfer the required oxygen from air to fuel using sulphated limestone as oxygen carrier for whatever coal used. However, coals with sulphur content above 1 wt.% are advisable to perform this process. In addition, no drawback referred to thermal integration in the system has been detected. Thus, operation at 950 ºC in the fuel reactor

Demonstrating the applicability of chemical looping combustion for the regeneration of fluid catalytic cracking catalysts

“…Chemical Looping Combustion (CLC) potentially offers lower energy penalties than PCC [7,8,12]. The CLC process, where metal oxides are used as an oxygen supplier instead of air to combust the fuel stream [14,15], has been suggested as an alternative process to decrease the CO2 capture cost [15][16][17]. In CLC, since air and fuel are never mixed [18], the technique does not need any separation process [14,19,20] unlike PCC [3][4][5][6]21], or OCC [9,11,22].…”

Use of natural ores as oxygen carriers in chemical looping combustion: A review

“…This process uses limestone (primarily CaCO 3 ) converted to CaSO 4 by sulfur released from coal, thus also achieving in-situ desulphurization. The process was recently reviewed by Abad et al (2017). The reduction kinetics of CaSO 4 with CO in a differential fixed bed is studied by Zheng et al (2011) and Xiao et al (2010b).…”

Environmental and Comparative Assessment of Integrated Gasification Gas Cycle with CaO Looping and CO2 Adsorption by Activated Carbon: A Case Study of the Czech Republic

“…The high-temperature purification process includes high-temperature desulphurization at temperatures between 800-900 • C. Desulphurization is done via adsorption of all the acidic impurities (e.g., H 2 S) on sorbent CaO/CaCO 3 (reaction (3)) [22] that comes from the carbonator . The waste product after the purification process is a mix of CaCO 3 + CaSO 4 , which is transported as waste to a landfill.…”