Testing of hydrotalcite-based sorbents for CO2 and H2S capture for use in sorption enhanced water gas shift

Regenerable magnesium-based sorbent for high-pressure and moderate-temperature CO2 capture: Physicochemical structures and capture performances

“…5(B)-(D)). These qualitatively illustrate that the chemical sorption of CO 2 is certain to occur during CO 2 capture, which has been also proved by some Literatures [1,2,14,15]. Consequently, it is concluded that the carbonation reaction of Mg(OH) 2 is certain to occur under the investigated capture conditions.…”

“…From Fig. 15(B), it is seen that the MS signal peaks of both CO 2 and H 2 S appear obviously as the decomposition temperature gradually increases to 400°C, suggesting that the co-exposed HS can be regenerated by simultaneously releasing CO 2 and H 2 S. The adsorption and regeneration mechanisms of the magnesium-based sorbent for H 2 S capture has been reported by van Dijk et al's investigation [14], which concluded that the main occurring reaction during capture and regeneration was the reversible reaction: Mg-(O-H) 2 + H 2 S M (H-O)-Mg-(S-H) + H 2 O. The above results illustrate that the prepared sorbent also can be adopted for the co-capture of CO 2 and H 2 S. However, from Figs.…”

“…This illustrates that H 2 S in the feed gas can importantly reduces the CO 2 capture capacity of the sorbent. This is obviously due to the competitive co-adsorption of CO 2 and H 2 S, which can been explained by the mechanistic model proposed by van Dijk et al [14].…”

“…A variety of solid sorbents for CO 2 capture have been studied and reported in Literatures. According to the CO 2 adsorption mechanisms, these solid sorbents can be classified into two types: physisorbents (microporous and mesoporous inorganic and organic materials such as zeolites [3], silica gel [4], activated carbon [5], and metal-organic frameworks (MOFs) [6]) and chemisorbents (Ca-based materials such as CaO [7], alkali metal-based materials such as NaOH [8], K 2 CO 3 [9] and Na 2 CO 3 [10], and Mg-based materials such as Mg(OH) 2 [1,2], MgO [11][12][13], hydrotalcite [14,15], and alkali metal-promoted hydrotalcite [16][17][18][19]). Usually, these physisorbents and chemisorbents for CO 2 capture are separately used in the pressure/temperature swing adsorption (PSA/TSA) system at relatively low temperatures (even near ambient temperature) and the TSA system at different temperatures [20].…”

“…Siriwardane et al [2] investigated the CO 2 adsorption performances of the Mg(OH) 2 sorbent at warm gas temperatures, and reported that the sorbent could exhibit a high CO 2 capture capacity of above 3 mmol/g at 200°C and was regenerable at 375°C under high pressures. van Dijk et al [14] investigated the CO 2 and H 2 S co-capture behaviors of the hydrotalcite-based sorbent (a similar sorbent), and considered that the sorbent could simultaneously eliminate CO 2 and H 2 S from the syngas. Ramirez-Moreno et al [15] made some investigations on the microstructure evolutions of the Mg-Al layered double hydroxide sorbent (a similar sorbent), and found that the double-layered structure of the sorbent was completely destroyed and no crystalline phase was detected at 325°C.…”