Synthesis, Pelleting, and Performance Evaluation of a Novel K-Promoted γ-Alumina/MgAl-Layered Double Oxide Composite Adsorbent for Warm Gas H₂/CO₂ Separation

Abstract

Development of stable solid adsorbent in pellet form is of importance for CO 2 /H 2 separation at elevated temperature (250−450°C). This study provides a novel synthesis method by adding K 2 CO 3 solution into alumina sol soaked MgAl-layered double hydroxide paste. The delay time of K 2 CO 3 addition is studied to demonstrate that the formation of Kpromoted γ-alumina is facilitated by an immediate addition. Extruded adsorbent of higher CO 2 capacity (0.65 mmol/g) and radial crushing strength (75.6 N per pellet) is obtained. The existing crystalline phase of obtained adsorbent is screened by X-ray diffraction. The adsorption capacity and adsorption kinetics of the developed adsorbent is characterized by a thermogravimetric analyzer in terms of calcination temperature of both dominant constituent materials, MG63 hydrotacite, and K-promoted pseudo boehmite. Crystal transit temperatures of the constituents are considered in selecting the optimal calcinations temperature. The adsorbent pellets, pretreated with the optimal parameters studied, are packed in a fixed-bed to test breakthrough curves of CO 2 , consistent dynamic capacity compared to that of thermogravimetric testing data were obtained. Results of multicycle CO 2 adsorption and desorption, steam sweeping, pressure change, and wear tests prove the stability of the adsorbent both in CO 2 capacity and mechanical strength.

Adsorption of CO2 on MgAl-CO3 LDHs-Derived Sorbents with 3D Nanoflower-like Structure

“…Up until now, the research on MgAl-CO 3 LDHs and MgAl-CO 3 LDHs-derived mixed oxides mainly concentrates on developing novel preparation methods, , replacing the intercalation inorganic or organic anions, , changing the molar ratio of Mg/Al, employing the supporters, − doping alkali metal (K, Na, Cs), and exploring sorption/desorption kinetics . Among diversified preparation methods, the coprecipitation method is the most common one.…”

Layered Double Hydroxides-Based Mixed Metal Oxides: Development of Novel Structured Sorbents for CO2Capture Applications

“…Apart from improving the CO 2 capture capacity and cycling stability, overcoming the particle size issue is a very important aspect on the development of CO 2 capture sorbents. There are efforts to address these issues in other high temperature sorbents such as CaO and Li 4 SiO 4 by developing structured forms of the materials. − However, these issues have been largely ignored for LDH-based MMOs sorbents. , …”

Desulfurization Kinetics and Regeneration of Silica Gel-Supported TiO2 Extrudates for Reactive Adsorptive Desulfurization of Real Diesel

“…The progress on dramatically enhanced adsorption selectivity and capacity of TiO 2 adsorbents by RADS unlocks its potential for ultradeep desulfurization of fuels, which is, however, still limited to powdered adsorbents. Due to the challenges of high-pressure drop of powdered adsorbents in the packed bed, as well as material losses in multiple cycles, molding TiO 2 -based ADS adsorbents into customizable forms and their regeneration are considered as essential steps and cannot be underestimated when considering potential industrial applications. , Most recent research studies have focused on the adsorption performance and mechanism of desulfurization. − However, studies on the adsorption kinetics and regeneration of molded materials are rarely reported. As indispensable parts of the RADS process, the adsorption kinetics of materials affect the desulfurization rate and the regeneration performance of adsorbents, which subsequently influence the adsorbent durability for industrial applications .…”

“…Due to the challenges of highpressure drop of powdered adsorbents in the packed bed, as well as material losses in multiple cycles, molding TiO 2 -based ADS adsorbents into customizable forms and their regeneration are considered as essential steps and cannot be underestimated when considering potential industrial applications. 31,32 Most recent research studies have focused on the adsorption performance and mechanism of desulfurization. 33−35 However, studies on the adsorption kinetics and regeneration of molded materials are rarely reported.…”