A Carbide Slag-Based, Ca12Al14O33-Stabilized Sorbent Prepared by the Hydrothermal Template Method Enabling Efficient CO2 Capture

Abstract

Calcium looping is a promising technology to capture CO2 from the process of coal-fired power generation and gasification of coal/biomass for hydrogen production. The decay of CO2 capture activities of calcium-based sorbents is one of the main problems holding back the development of the technology. Taking carbide slag as a main raw material and Ca12Al14O33 as a support, highly active CO2 sorbents were prepared using the hydrothermal template method in this work. The effects of support ratio, cycle number, and reaction conditions were evaluated. The results show that Ca12Al14O33 generated effectively improves the cyclic stability of CO2 capture by synthetic sorbents. When the Al2O3 addition is 5%, or the Ca12Al14O33 content is 10%, the synthetic sorbent possesses the highest cyclic CO2 capture performance. Under harsh calcination conditions, the CO2 capture capacity of the synthetic sorbent after 30 cycles is 0.29 g/g, which is 80% higher than that of carbide slag. The superiority of the synthetic sorbent on the CO2 capture kinetics mainly reflects at the diffusion-controlled stage. The cumulative pore volume of the synthetic sorbent within the range of 10–100 nm is 2.4 times as high as that of calcined carbide slag. The structure of the synthetic sorbent reduces the CO2 diffusion resistance, and thus leads to better CO2 capture performance and reaction rate.

Review of Carbonate-Based Systems for Thermochemical Energy Storage for Concentrating Solar Power Applications: State-of-the-Art and Outlook

“…The multicyclic performances of Al 2 O 3 -supported CaO-based sorbents are summarized in Table . When Al 2 O 3 is incorporated into CaO-based sorbents, different Ca-Al mixed oxides (such as Ca 3 Al 2 O 6 , Ca 5 Al 6 O 14 , Ca 9 Al 6 O 18 , and Ca 12 Al 14 O 33 ) are formed, as also shown in Table ; as a consequence, these CaO particles are stabilized thanks to an increased sintering resistance during the multicyclic operations. It is important to underline that the achievable multicyclic performance of the Al 2 O 3 -stabilized sorbent is greatly affected by the synthesis procedure since it determines how the CaO and Al 2 O 3 (or Ca-Al mixed oxides) are distributed in the final material .…”

“…84 Among the materials forming mixed oxide with CaO, Al 2 O 3 is also one of the most commonly used support, thanks to its quite high T t (900 °C, Table 6), low cost, and good mechanical strength. 84 The multicyclic performances of Al 2 O 3 -supported CaO-based sorbents are summarized in 139 are formed, as also shown in Table 7; as a consequence, these CaO particles are stabilized thanks to an increased sintering resistance during the multicyclic operations. It is important to underline that the achievable multicyclic performance of the Al 2 O 3 -stabilized sorbent is greatly affected by the synthesis procedure since it determines how the CaO and Al 2 O 3 (or Ca-Al mixed oxides) are distributed in the final material.…”

Enhanced Sewage Sludge Gasification by Bauxite‐Modified Carbide Slag for Hydrogen‐Rich Syngas Production with In Situ CO2 Capture

“…where 8), which plays an important role in improving the reactivity of cyclic CO 2 capture of CaO. [9,38] 7Al 2 O 3 þ 12CaO ! Ca 12 Al 14 O 33 (8) The mechanical strength of various carbide slag sorbents is shown in Table 3.…”

“…The loss of CO 2 absorption capacity caused by sintering and attrition is a key challenge to use CaO-based sorbents for CO 2 capture. [9][10][11] To improve the stability of carbide slag to capture CO 2 during cyclic carbonation, [12,13] different methods such as the carbon microsphere template method, [14] extruded spheroidal method, [15] and liquid-phase precipitation [16] have been tested by adding inert materials. However, the produced sorbents by aforementioned methods using pore-forming materials such as microcrystalline cellulose, glucose, etc., or inert supports like NiO and ZrO 2 still need to evaluate the sorbent cost in large-scale application.…”

Review on the Development of Sorbents for Calcium Looping

“…Al 2 O 3 is the most commonly used support as a result of its high T t , good mechanical strength, and low cost. A series of Ca–Al mixed oxides, such as Ca 3 Al 2 O 6 , Ca 5 Al 6 O 14 , Ca 9 Al 6 O 18 , and Ca 12 Al 14 O 33 , are formed when Al 2 O 3 is incorporated into the CaO-based sorbents (as shown in Table ), which effectively stabilize the CaO particles and retard their sintering during cyclic operation. Hu et al used a wet mixing method to prepare synthetic CaO-based sorbents stabilized by different supports, aiming to screen the optimal inert support for the CaO-based sorbents .…”