Attrition characteristics of Ca-based dual functional material in a micro fluidized-bed reactor for integrated CO2 capture and conversion

Abstract

Integrated carbon capture and utilization coupled with reverse water-gas shift reaction is a promising technology for converting captured CO₂ into value-added CO or syngas using a Ca-based dual functional material (DFM). However, existing Ca-based DMFs are primarily powder-based formulations, which poses challenges for their direct application in a real fluidized-bed reactor, and the attrition characteristics of DFM particles remain largely unexplored. Herein, a micro-fluidized-bed thermogravimetric analyzer coupled with a mass spectrometer (MFB-TGA-MS) was employed to investigate the attrition properties of three types of well-prepared Ca-based DFM particles under fluidizing conditions. It was found that Al-modified Ca-based DFM retained ∼6 mmol g^-1 CO₂ after 100 cycles, but high forming pressure reduced this to ∼4 mmol g^-1 while low pressure caused 2.24 % h^-1 physical loss in the first 10 cycles. Physical loss peaked within 20 cycles, while chemical loss occurred mainly before cycle 40 for the DFM without Al and shifted to cycles 40–80 with Al. SEM and TEM confirmed that the Al skeleton is beneficial for reducing the chemical loss via suppressing the sintering of Ni and CaO. However, high pellet-forming pressure would lessen the pore structure, hindering the volume change during the capture and hydrogenation processes. Finally, the integrated carbon capture and utilization - reverse water gas shift (ICCU-RWGS) performance was analyzed over a wide range of CO₂ and H₂ partial pressures. Decoupling of DFM particle attrition into chemical loss and physical loss provides insight to develop a highly efficient DFM particle.