TY - JOUR
T1 - High-temperature CO2 capture by fly ash derived sorbents
T2 - Effect of scale-up on sorbents performance
AU - Fermoso, Javier
AU - Sanna, Aimaro
N1 - Funding Information:
The authors thank the Innovate UK Technology Strategy Board (Grant n°. 132397 ) and EPSRC (Grant n°. EP/P018955 ) for funding support. PYRO YIELD Ltd and especially Dan Morgan are acknowledged for their technical support with the synthesis of the large batch of material and its performance on high temperature CO 2 capture. LAFARGE CEMENT is also acknowledged for providing fly ash samples.
Funding Information:
The authors thank the Innovate UK Technology Strategy Board (Grant n?. 132397) and EPSRC (Grant n?. EP/P018955) for funding support. PYRO YIELD Ltd and especially Dan Morgan are acknowledged for their technical support with the synthesis of the large batch of material and its performance on high temperature CO2 capture. LAFARGE CEMENT is also acknowledged for providing fly ash samples.
Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2022/2/1
Y1 - 2022/2/1
N2 - Dry sorbent high temperature CO2 capture process is a promising technology to remove CO2 efficiently from flue gas. Here we report the performance of fly ash derived potassium-aluminium silicates sorbents (K-FAs) for high-temperature CO2 capture at different scale setups, from milligrams to hundred kilograms. Li2CO3 and Na2CO3 were evaluated as promoters by their incorporation at 10 – 20 wt% on the sorbents for pure (100 vol%) or diluted (14 vol%) CO2 capture. The properties of the K-FAs sorbents were characterised by a number of techniques and linked to their performance and cyclability. The maximum CO2 uptake of 2.82 mmol CO2/gsorbent was achieved with K-FAs_20%Li with pure CO2 using a thermogravimetric set-up, while K-FAs_20%Na exhibited the faster CO2 adsorption and no CO2 capture decay in 10 consecutive cycles when tested in a fixed bed reactor, which was linked to enhanced diffusion of CO2 and Na due to the smaller crystals (33 nm), smaller particles (56.3 µm) and larger pores (16.9 nm) compared to the Li and Li-Na doped K-FAs sorbents. SEM-EXD analyses indicate formation of K/Na eutectic melt on surface, which also facilitates CO2 and K diffusion and protect from strong sintering. The capability of deploying the K-FAs_20%Na sorbent at 100 kg scale was also demonstrated with the separation of 6 kg CO2/h (from a 50 kg/h biomass pyrolysis unit) at 700 °C in 30 min cycles. The gas recovered in the desorption stage had a purity of 55 mol% in wet basis and 80 mol% in dry basis, suggesting improvements are required to achieve ≥ 90% efficiency. Detailed kinetics analysis concluded that the adsorption of CO2 on K-FAs sorbents could be described by double exponential kinetics and the diffusion was found to be governed by a mixture of different mechanisms with intramolecular particle being the prominent. The accessibility and cost-effectiveness of K-FAs_20%Na and its performances render it as interesting candidate sorbents for high temperature CO2 capture only at small scale.
AB - Dry sorbent high temperature CO2 capture process is a promising technology to remove CO2 efficiently from flue gas. Here we report the performance of fly ash derived potassium-aluminium silicates sorbents (K-FAs) for high-temperature CO2 capture at different scale setups, from milligrams to hundred kilograms. Li2CO3 and Na2CO3 were evaluated as promoters by their incorporation at 10 – 20 wt% on the sorbents for pure (100 vol%) or diluted (14 vol%) CO2 capture. The properties of the K-FAs sorbents were characterised by a number of techniques and linked to their performance and cyclability. The maximum CO2 uptake of 2.82 mmol CO2/gsorbent was achieved with K-FAs_20%Li with pure CO2 using a thermogravimetric set-up, while K-FAs_20%Na exhibited the faster CO2 adsorption and no CO2 capture decay in 10 consecutive cycles when tested in a fixed bed reactor, which was linked to enhanced diffusion of CO2 and Na due to the smaller crystals (33 nm), smaller particles (56.3 µm) and larger pores (16.9 nm) compared to the Li and Li-Na doped K-FAs sorbents. SEM-EXD analyses indicate formation of K/Na eutectic melt on surface, which also facilitates CO2 and K diffusion and protect from strong sintering. The capability of deploying the K-FAs_20%Na sorbent at 100 kg scale was also demonstrated with the separation of 6 kg CO2/h (from a 50 kg/h biomass pyrolysis unit) at 700 °C in 30 min cycles. The gas recovered in the desorption stage had a purity of 55 mol% in wet basis and 80 mol% in dry basis, suggesting improvements are required to achieve ≥ 90% efficiency. Detailed kinetics analysis concluded that the adsorption of CO2 on K-FAs sorbents could be described by double exponential kinetics and the diffusion was found to be governed by a mixture of different mechanisms with intramolecular particle being the prominent. The accessibility and cost-effectiveness of K-FAs_20%Na and its performances render it as interesting candidate sorbents for high temperature CO2 capture only at small scale.
KW - Fly ash
KW - High-temperature CO capture
KW - Lithium
KW - Potassium silicates
KW - Sodium, scale-up
UR - http://www.scopus.com/inward/record.url?scp=85114665696&partnerID=8YFLogxK
U2 - 10.1016/j.cej.2021.132201
DO - 10.1016/j.cej.2021.132201
M3 - Article
SN - 1385-8947
VL - 429
JO - Chemical Engineering Journal
JF - Chemical Engineering Journal
M1 - 132201
ER -