title: Potassium-based sorbents from fly ash for high-temperature CO2capture.
abstract: Potassium-fly ash (K-FA) sorbents were investigated for high-temperature CO2sorption. K-FAs were synthesised using coal fly ash as source of silica and aluminium. The synthesised materials were also mixed with Li2CO3and Ca(OH)2to evaluate their effect on CO2capture. Temperature strongly affected the performance of the K-FA sorbents, resulting in a CO2uptake of 1.45 mmol CO2/g sorbent for K-FA 1:1 at 700 °C. The CO2sorption was enhanced by the presence of Li2CO3(10 wt%), with the K-FA 1:1 capturing 2.38 mmol CO2/g sorbent at 700 °C in 5 min. This sorption was found to be similar to previously developed Li-Na-FA (2.54 mmol/g) and Li-FA (2.4 mmol/g) sorbents. The presence of 10 % Li2CO3also accelerated sorption and desorption. The results suggest that the increased uptake of CO2and faster reaction rates in presence of K-FA can be ascribed to the formation of K-Li eutectic phase, which favours the diffusion of potassium and CO2in the material matrix. The cyclic experiments showed that the K-FA materials maintained stable CO2uptake and reaction rates over 10 cycles.
authors.affiliation: Centre for Innovation in Carbon Capture and Storage (CICCS), School of Engineering and Physical Sciences, Heriot-Watt University, 3.04 Nasmyth Building, Edinburgh, EH14 4AS, UK. A.Sanna@hw.ac.uk.
authors.forename: Aimaro
authors.initials: A
authors.lastname: Sanna
authors.affiliation: Centre for Innovation in Carbon Capture and Storage (CICCS), School of Engineering and Physical Sciences, Heriot-Watt University, 3.04 Nasmyth Building, Edinburgh, EH14 4AS, UK.
authors.forename: M Mercedes
authors.initials: MM
authors.lastname: Maroto-Valer
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry*; D003031:Coal; D060729:Coal Ash / Q000737:chemistry*; D003247:Conservation of Natural Resources; D006358:Hot Temperature; D008094:Lithium; D011188:Potassium / Q000737:chemistry*
chemical_list: D003031:Coal; D060729:Coal Ash; D002245:Carbon Dioxide; D008094:Lithium; D011188:Potassium
keywords: Absorption; CCS; CO2 sorbents; Fly ash; Potassium