Metal oxide-stabilized calcium oxide CO2 sorbent for multicycle operation

A highly efficient CaO-based CO2 sorbent prepared by a citrate-assisted sol–gel technique

“…Ridha et al [44] reported a CO 2 adsorption capacity of 12 wt% after the 20th cycle for an acidified limestone stabilized with 10% cement (calcination at 920°C in the presence of 100% CO 2 ). Radfarnia and Iliuta [11] proposed an Al 2 O 3 -stabilized limestone (CaO-Ca 9 Al 6 O 18 ) that could preserve 23 wt% CO 2 capacity during severe calcination condition (50% CO 2 /N 2 and 930°C). Recently, Angeli et al [24] reported a CO 2 capture of 27 wt% at the 30th cycle of sorption for their proposed CaO-Ca 3 Al 2 O 6 material.…”

“…Researchers focused mainly on improving the structure and thermal resistance of CaO either by introducing a metal oxide stabilizer phase or exploring different Ca-precursors leading to improved properties. An extensive range of metal oxide stabilizers was used to enhance the stability of CaO, including Zr, Al, Ti and Si oxides [8][9][10][11][12][13][14][15][16]. A key point toward large-scale application of any CO 2 sorbent is its production cost.…”

High temperature CO2 sorbents and their application for hydrogen production by sorption enhanced steam reforming process

“…The transition between steps 3 and 4 depends on the precursors used during the synthesis step, which can limit Ca 2+ diffusion into the stabilizer structure for further reaction. (1) Recently, different research groups have developed various synthesis methods with the aim of increasing surface area and pore volume and obtaining high dispersion of inert supports within the sorbent structure: wet mixing [12,63,65,66,68,70], limestone acidification by citric acid followed by two step calcination [71], solid state reaction [72], ultrasonic spray pyrolysis (USP) [73], combination of precipitation and hydration [74], coprecipitation [75], citrate preparation [64], sol-gel [77,79], citrate-assisted sol-gel technique followed by two-step calcination [78], single nozzle flame spray pyrolysis (FSP) [69], and precipitation [80]. [89].…”

Improving the stability of synthetic CaO-based CO 2 sorbents by structural promoters

“…Although a high initial capacity is important in order to minimize the amount of sorbent circulating between the two reactors, maintaining or recovering this high capacity after multiple cycles, plays an equally important role. Different approaches have been applied to improve the cyclic stability of the sorbents, including thermal pre-treatment [47,48], incorporation of inert thermally resistant materials in the structure of CaO [49][50][51][52][53][54][55][56] and reactivation through water or steam hydration [57,58]. Different synthesis methods have also been employed in order to improve the stability of CaO, including precipitation, dry or wet mixing, flame spray pyrolysis and several modified sol-gel routes [49,51,53,[59][60][61][62][63].…”