High-Temperature CO2 Capture Using Regenerable Ca-Mg-based Sorbents Derived from Natural Minerals: Huntite, Hydromagnesite, and Magnesite

Autor: Sena Yasyerli, Dilsad Dolunay Eslek Koyuncu, Nail Yasyerli
Rok vydání: 2021
Předmět:
Zdroj: Arabian Journal for Science and Engineering. 47:6269-6281
ISSN: 2191-4281
2193-567X
Popis: In this study, performances of three different natural minerals, namely magnesite, hydromagnesite, and huntite, were investigated as regenerable Ca-Mg-based sorbents for high-temperature CO2 capture. XRD analyses results showed that these raw minerals contained different forms of Ca and Mg oxides, such as Mg-5(CO3)(4)(OH)(2).4H(2)O-hydromagnesite, MgCO3-magnesite, CaMg3(CO3)(4)-huntite, and CaMg(CO3)(2)-dolomite. In order to obtain CaO as an active phase, natural minerals were calcined at different temperatures (900-950 degrees C) as defined by TGA-DTA analyses. After activation, CaO and MgO phases were obtained in all of these sorbents. High-temperature CO2 removal tests were performed in a continuous-flow fixed-bed reactor system in the temperature range of 400-700 degrees C with a GHSV of 3600 cm(3)h(-1) g(-1). CO2 sorption capacities were determined using breakthrough curves and TGA-DTA analyses. Following CO2 sorption, CaCO3 formation via carbonation of the CaO phase was determined by TGA-DTA and XRD analyses. CO2 sorption capacities of huntite, hydromagnesite, and magnesite-derived sorbents were found as 3.5, 2.0, and 0.4 mmol CO2/gsorbent at 550 degrees C, respectively. In the experiments carried out at different temperatures using huntite-derived sorbent, the highest CO2 sorption was observed in the pre-breakthrough region at 550 degrees C. Huntite-derived sorbent was found to be highly stable after 10 cycles and its stability was attributed to the presence of MgO as an inert phase in the sorbent. After ten cycles, the huntite-derived sorbent maintained about 73% of its first cycle sorption capacity. It was concluded that the huntite-derived material is a promising sorbent for high-temperature CO2 capture based on using 83% of its CaO content in its structure.
Databáze: OpenAIRE
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