Screening of inert solid supports for CaO-based sorbents for high temperature CO2 capture

• A screening of 12 inert supports for CaO-based sorbents was conducted.
• For the first time, 2 inert supports were used to improve the CaO performance.
• BET surface area and melting point were found to affect the sorbent performance.

A screening of inert solid supports as metal skeletons of CaO-based sorbents was conducted in this work, aiming to provide the basis and guideline for the selection of inert solid refractories to produce high temperature CO2 capture sorbent. We studied 12 different refractories including Al-, Ti-, Mn-, Mg-, Y-, Si-, La-, Zr-, Ce-, Nd-, Pr- and Yb-based supports, among which Yb and Pr are newly introduced ones. The sorbents were synthesized using the same wet-mixing method, by which the inert supports could be well dispersed among the ultra-fine active specie of CaO/CaCO3 particles to fully play the role of frameworks for sintering resistance. The sorbents stabilized by these inert supports were also cyclically tested under the same conditions. Y- and Al-based supports were found to exhibit much superior cyclic performance than the other supports. Mn-, Mg-, La-, Yb- and Nd-based supports are also good candidates, whereas the other ones containing Ti-, Ce-, Zr-, Si- and Pr-based supports show less effectiveness. The melting point of the inert support and surface area of the synthetic sorbents are found to be the key factors to affect the sorbent performance.

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