Evaluation of high-temperature CO2 capture performance of cellulose-templated CaO-based pellets

• Published in: Fuel (Guildford) 2019-03, Vol.239, p.1046-1054
• Main Authors: Sun, Jian, Liang, Cheng, Tong, Xianliang, Guo, Yafei, Li, Weiling, Zhao, Chuanwen, Zhang, Jubing, Lu, Ping
• Format: Article
• Language: English
• Subjects: Cellulose-templated pellet; CO2 capture; Particle size; Pre-calcination conditions
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2018.11.123

[Display omitted] •Cellulose addition improves CO2 capture performance of CaO-based sorbent pellets.•Pellet size scarcely affects CO2 uptake of sorbent pellets.•Cellulose particle size limitedly affects CO2 uptake of cellulose-templated pellets.•Coal combustion causes dramatic CO2 uptake decrease of cellulose-templated sorbent pellets. The addition of biomass-based pore-forming templates is an effective approach to improve CO2 capture performance of CaO-based pellets. In this work, cellulose-templated CaO-based pellets were prepared via an extrusion-spherization method. The cyclic CO2 uptake capacity of cellulose-templated pellets was investigated with the variation of pellet size, particle size of cellulose and pre-calcination conditions. It is found that the smaller pellets possess the faster CO2 capture rate during chemical reaction-controlled stage, while the pellet size scarcely affects the ultima CO2 capture capacities of cellulose-templated pellets in 30 min carbonation. Although the addition of cellulose template contributes to enhance CO2 uptake of CaO-based sorbent pellets (over 0.32 g CO2/g sorbent after 25 cycles), the particle size of cellulose plays a limited role on the CO2 capture performance enhancement effectiveness. Additionally, the cellulose-templated pellets pre-calcined under severe conditions (air calcination and coal combustion) exhibit the inferior, initial CO2 capture capacities due to the excessive sintering as a result of heat release of cellulose and coal combustion. However, severe pretreatments are rewarding to improve the CO2 sorption stability of cellulose-templated sorbent pellets because of the generation of large amounts of micro-sized cavities which are less sensitive to sintering.