Carbon capture from steam methane reforming (SMR) stream by Supported Ionic Liquids (SILPs) using commercial supports

The selective capture of CO 2 from reforming stream for H 2 productions was evaluated in fixed-bed columns using Supported Ionic Liquid Phases (SILP) based on commercial ionic liquid 1-butyl-3-methylimidazolium acetate ([Bmim][Acetate]). Thirteen different commercial supports were evaluated, varying in particle size, porosity and surface chemistry. Selected supports were used to prepare SILP materials via incipient wetness impregnation, incorporating ~40 wt% IL. Supports and SILP sorbent characterization were performed using scanning electron microscopy, nitrogen adsorption-desorption isotherms and thermogravimetric and elemental analysis. A synthetic gas mixture modeling a Steam Methane Reforming (SMR) stream with composition of H 2 /CO 2 /CH 4 (70/25/5%) was used to evaluate the CO 2 capture performance of the six different SILP materials by means of fixed-bed experiments. Measured breakthrough curves at 30 ºC under various operating pressures (1, 5, and 10 bar) allowed to estimate thermodynamic and kinetic parameters on CO 2 sorption from SMR gas model. The experimental fixed-bed tests revealed CO 2 sorption capacities of 0.4–0.6 mol·kg⁻¹, with pre-breakthrough times up to 20 min and CO 2 removal efficiencies above 90% at 10 bar. Thermodynamics (sorption capacity) was maintained independently of the support, while particle size governed sorption/desorption kinetics, with smaller particles exhibiting faster mass transfer and more efficient use of the sorbent. Increasing CO 2 partial pressure enhanced both sorption capacity and kinetic constants, leading to improved process performance. The LDF model successfully described the experimental breakthrough curves, using K MTC as reference kinetic parameter. Additionally, regeneration tests, using a N 2 stripping stream and pressure-swing, were conducted on one selected SILP material over seven sorption-desorption cycles. So, experimental results highlighted the improved performance of SILP materials with smaller particle sizes, with high effective CO 2 sorption capacity and enhanced sorption and desorption rates, enabling treating SMR streams by a simple two-fixed bed configuration. • 13 supports of very different nature were evaluated as SILP in CO 2 capture from SMR streams • The amount of IL in SILP determined the CO 2 sorption capacity • Higher IL loadings were reported in supports with high BET surfaces and mesopore volumes • The support particle size is the key parameter of the CO 2 sorption kinetics • The reusability of the SILP was demonstrated by 7 sorption/desorption cycles preserving CO 2 sorption capacity