CO₂ Sorption Enhancement of Extruded-Spheronized CaO-Based Pellets by Sacrificial Biomass Templating Technique

Abstract

The sacrificial biomass templating technique was used to enhance the sorption performance of CaO-based pellets that were prepared via an extrusion-spheronization method. Five types of biomass materials were used as the templates: microcrystalline cellulose, corn starch, rice husk, sesbania powder, and lycopodium powder. It is found that the addition of biomass templates is effective to improve the cyclic CO2 sorption capacity of the CaO-based pellets. However, two opposite enhancement tendencies of CO2 uptake were observed with the increment of biomass addition. For microcrystalline cellulose, corn starch, and rice husk, more addition amounts would result in better improvement of CO2 sorption performance of the CaO-based pellets. It is attributed to the generated porous microstructure and large amounts of small grains. However, for sesbania powder and lycopodium powder, a decreasing enhancement tendency of the CO2 sorption performance was found with the increasing addition amount. It is probably due to the accelerated sintering of the sorbent because of the presence of excessive amounts of alkali metal elements. Moreover, all biomass-templated CaO-based pellets possess a high anti-attrition capacity.

Increasing Porosity of Molded Calcium‐Based Sorbents by Glucose Templating for Cyclic CO2 Capture

“…The isothermal N 2 adsorption‐desorption curves of these samples exhibit a type II isotherm sorption behavior , which was associated with the mesoporous and macroporous structure of the samples, as displayed in Fig. a.…”

Acidification Optimization and Granulation of a Steel‐Slag‐Derived Sorbent for CO2 Capture

“…. These unimodal CO 2 capture rate curves consist of three segments (i.e., a steeply rising segment, a rapid declining segment, and a horizontal segment), corresponding to a stage controlled by chemical reaction, a transition stage, and a stage controlled by product‐layer diffusion , respectively. The chemical‐reaction‐controlled and transition stages make the major contribution to the CO 2 uptake of the sorbent (denoted fast CO 2 sorption stage in this work).…”

“…Although some nanosized grains are present on the surface of CAS‐E, larger amounts of dense, sintered blocks clearly decrease its porosity and therefore result in the inferior cyclic CO 2 uptake of the extruded pellets. The addition of an appropriate amount of pore‐forming materials, such as microcrystalline cellulose, starch, or rice husk, can effectively modify the pore structures of granulated sorbents , .…”

“…Approximately 25–30 mg of sample was calcined at 850 °C for 2 min under a N 2 flow rate of 100 mL min −1 , and the carbonation reaction of the calcined sample was conducted at 650 °C for 30 min under 15 vol % CO 2 (N 2 as balance gas). Specific information on the testing conditions can be found in the literature . The carbonation/calcination cycle was repeated 25 times.…”

“…To the best of our knowledge, further investigations of the effect of acetic acid pretreatment conditions on the CO 2 capture performance of steel‐slag‐derived sorbents by means of orthogonal experimental design have never been conducted. Moreover, the steel‐slag‐derived sorbents are generally in the form of powder, which is easily elutriated from the fluidized‐bed reactors during carbonation/calcination cycles . To maintain stable CO 2 capture efficiency, additional fresh sorbent must be added to replenish the elutriated sorbent, and consequently the cost of CO 2 capture is increased , .…”