Molten shell-activated, high-performance, un-doped Li4SiO4 for high-temperature CO2 capture at low CO2 concentrations

Abstract

Lithium orthosilicate (Li4SiO4) represents a potential class of hightemperature sorbents for CO2 capture in power plants and sorption enhanced methane reforming to produce H2. However, conventional wisdom suggests that pure Li4SiO4 would have extremely slow sorption kinetics at realistic low CO2 concentrations. Here, we report the opposite result: using a simple and cost-effective glucose-based mild combustion procedure, an unusually efficient and pure form of Li4SiO4 (MC-0.6) was synthesized to achieve a maximum uptake capacity of 35.0 wt.% at 580 °C for CO2 concentrations under 15 vol.% and maintained this capacity over multiple cycles. The characterization results showed that highly porous nano-agglomerate-like (50-100 nm) morphologies were apparent and ensured a rapid surface-sorption of CO2. In this process, a macroporous nano-sized Li2SiO3 cover on the melt layer of Li2CO3 was

Efficient-and-stable CH4 reforming with integrated CO2 capture and utilization using Li4SiO4 sorbent

“…However, pure Li 4 SiO 4 has poor sorption performance at low CO 2 concentration. Modification of Li 4 SiO 4 is needed to improve its CO 2 sorption performance, including the treatment by organic acids [26] , alkali improvement [27] and doping of other metals [28,29] . In particular, K 2 CO 3 -doped Li 4 SiO 4 shows excellent sorption performance and cycling stability at low CO 2 concentrations, suggesting its potential as a sorbent for ICCU-DRM with long-term stability.…”

Synergistic promotions of K doping on CO2 capture and in situ conversion

“…[7][8][9][10][11] However, the high operating temperature above 700 C not only aggravates the sintering of sorbents and catalysts, 12 but also makes it more costly and challenging for large-scale industrial deployments due to the strict heat-resistant requirements for the installation materials, the high energy consumption, and the safety issues. 5,[13][14][15] In contrast, the alkaline ceramic materials, such as Li 4 SiO 4 through the lithium-looping (LiL, Li 4 SiO 4 + CO 2 $ Li 2 SiO 3 + Li 2 CO 3 ), [16][17][18][19] exhibit a high CO 2 capture capability and excellent cycle stability in a relatively lower temperature range of 500-600 C. [20][21][22][23] To match this CO 2 capture temperature, the revised water gas shift (RWGS) reaction can be a more promising choice than the dry reforming of methane (700-800 C) and CO 2 methanation (300-400 C) for the in situ CO 2 conversion. [24][25][26][27][28] However, there is few research working on the LiL@RWGS-based iCCC technology, which can be caused by the scarcity of lithium resources due to the fast development of lithium-ion batteries (LIBs).…”