A Review of CO2 Capture by Absorption and Adsorption

Abstract

Global warming resulting from the emission of greenhouse gases, especially CO 2 , has become a widespread concern in the recent years. Though various CO 2 capture technologies have been proposed, chemical absorption and adsorption are currently believed to be the most suitable ones for post-combustion power plants. The operation of the chemical absorption process is reviewed in this work, together with the use of absorbents, such as the ionic liquid, alkanolamines and their blended aqueous solutions. The major concerns for this technology, including CO 2 capture efficiency, absorption rate, energy required in regeneration, and volume of absorber, are addressed. For adsorption, in addition to physical adsorbents, various mesoporous solid adsorbents impregnated with polyamines and grafted with aminosilanes are reviewed in this work. The major concerns for selection of adsorbent, including cost, adsorption rate, CO 2 adsorption capacity, and thermal stability, are compared and discussed. More effective and less energy-consuming regeneration techniques for CO 2 -loaded adsorbents are also proposed. Future works for both absorption and adsorption are suggested.

Feasibility of CO2 adsorption by solid adsorbents: a review on low-temperature systems

“…Thus, the kinetics of adsorption and desorption controls the cycle time and the amount of adsorbent required in the adsorption system. The faster an adsorbent can adsorb/desorbed CO 2 , the less amount of adsorbent will be needed to capture a given volume of CO 2 (Samanta et al 2011;Yu et al 2012). It has been reported that the overall kinetics of CO 2 adsorption is influenced by functional groups present, as well as the pore size and distribution in the support.…”

“…If an appropriate sorbent and proper operation conditions are chosen, continuous removal of CO 2 up to 80 % can be achieved with ease under favorable economics Park et al 2006a, b). Various metal oxides such as Na-, K-and Libased materials are considered to be efficient for the CO 2 adsorption operation, but the seriousness of diffusion resistance has hindered their commercial consumption (Iwan et al 2009;Yu et al 2012). The attrition or abrasion resistance affects the CO 2 capture.…”

“…In a water-gas shift reaction (WGSR), steam is added to the syngas converting CO to hydrogen and CO 2 . After physical wash, CO 2 is separated and dehydrated from the gas stream leaving H 2 behind, which is a clean source of energy (Jin and Zhang 2011;Yu et al 2012). Oxy-fuel technology burns fuel and pure oxygen instead of ambient air.…”

“…Therefore, it is not necessary that the CO 2 adsorption will increase with the increase of surface area (Maroto-Valer et al 2005;Reddy et al 2015). The other approach is to form structures of single-walled carbon nanotubes (CNTs), multi-walled CNTs, graphenes, ordered mesoporous carbon, microporous carbon (Yu et al 2012). In Table 1, different reagents and their general effects on CO 2 adsorption in carbonaceous material-based adsorbents are summarized.…”

Polyethyleneimine functionalised nanocarbons for the efficient adsorption ofcarbon dioxide with a low temperature of regeneration

“…[28] A comparison of CO 2 absorption performance of PEI-GO and three different kinds of PEI-impregnated mesoporous silica substrates [29] is given in Table 3. The absorption capacity of PEI-GO is comparable to that of KIT-6-PEI at 25 C. …”