CO₂ Capture Performance of Mesoporous Synthetic Sorbent Fabricated Using Carbide Slag under Realistic Calcium Looping Conditions

Abstract

Calcium looping is techno-economically feasible for industrial CO 2 reduction. Carbide slag as a waste from the PVC (polyvinyl chloride) industry is a good candidate for low-cost calcium-based CO 2 sorbents. A novel synthetic sorbent with rich mesopores was fabricated from high alumina cement, carbide slag, and byproduct of biodiesel, in order to overcome the loss in CO 2 capture capacity of calcium-based sorbents with the number of carbonation/calcination cycles. The CO 2 capture capacities of synthetic sorbents were examined under the severe calcination condition of high CO 2 concentration and high temperature, which is close to the actual atmosphere for industrial applications. The effects of high alumina cement addition, byproduct of biodiesel addition, calcination condition, and steam addition in carbonation atmosphere on CO 2 capture by the synthetic sorbents were also discussed. Results show that the synthetic sorbent with 90 wt % CaO achieves the highest CO 2 capture capacity of about 0.27 g/g after 30 cycles under the realistic calcination condition, which is 1.7 times higher than that of carbide slag. N 2 physisorption measurement reveals typical mesoporous structure in the synthetic sorbent with 90 wt % CaO and large amounts of pores in the range of 10−100 nm are maintained over 10 cycles. C 12 A 7 (Ca 12 Al 14 O 33 ) and C 2 AS (Ca 2 Al 2 SiO 7 ) are found in the synthetic sorbent, which are uniformly distributed as the pore skeleton between CaO grains. The combining effect of the mesoporous structure and stabilization of pores over the repeated cycles is responsible for the high CO 2 capture capacity of the synthetic sorbent. The synthesized mesoporous CO 2 sorbent appears promising for the implementation of the cost-effective CO 2 capture technique.

Self-activated, nanostructured composite for improved CaL-CLC technology

“…It is interesting to notice that large amounts of mesopores were found in the interiors of grains, as shown in Fig. 9d, which was considered to be beneficial for CO 2 uptake [26,27]. Moreover, the shape of the grains in the CaO/CuO matrix composites differed greatly with a decreasing molar ratio of CaO to CuO in the composites, changing from nearly spherical to long strips.…”

“…As shown in Fig. 8, there is a clear increase in the pore size distribution of 2-50 nm when CaO-CuO-1-800-30 underwent 15 repeated cycles, which is beneficial for CO 2 uptake capacity since it plays a critical role in CO 2 capture [26]. The increases of both specific surface area and pore volume lead to the increase of CO 2 uptake capacity, i.e., the occurrence of self-activation.…”

“…Moreover, an additional step, i.e., the high-temperature product calcination that typically follows the conventional synthesis method, can be eliminated via SCS [25]. Li et al [26][27][28][29] For simplicity, the abbreviation CaO-CuO-x-T-t is used to denote the different CaO/CuO matrix composites, where x represents the molar ratio of CaO to CuO, T is the combustion temperature (°C), and t is the combustion duration (min). Here, the abbreviation CuO* is used for the pure CuO sorbent, which is synthesized at a combustion temperature of 800°C for a duration of 30 min.…”

Calcium‐Based Sustainable Chemical Technologies for Total Carbon Recycling

“…The sorbent achieves its highest capturec apacity of about 0.27 gg À1 after 30 cycles.T his is 1.7 times highert han that of CS. [138] The CO 2 capturep erformance of C-H-90 during multiple cycles is 1.7 and 2.6 times higher than that of CS and limestone, respectively (Figure 25).…”

“…N = number of cycles; C N = capacity of the sorbent. Reproduced from Ref [138]. with permission from American Chemical Society.…”