Improved Sorption‐Enhanced Steam Methane Reforming via Calcium Oxide–Based Sorbents with Targeted Morphology

Abstract

Calcium oxide (CaO)‐based sorbents for sorption enhanced steam methane reforming (SE‐SMR) that achieve stoichiometric capacity are synthesized via thermal and electrospinning methods. Small CaO crystallites (39 nm) and macroporous intrafiber networks imparted by electrospinning lead to stoichiometric capacities (0.79 normalgCO2 normalgsorbent−1) and uptake kinetics (first order rate constant, k = 8.9 × 10−4 ± 1.8 × 10−5 cm4 mol−1 s−1) at 873 K that are superior to CaO derived from thermal syntheses (0.05−0.7 normalgCO2 normalgsorbent−1 and k < 5.0 × 10−4 ± 2.5 × 10−6 cm4 mol−1 s−1). Al‐doped electrospun CaO samples (Al:Ca ratios of 3:10, 1:10 and 2:10) also exhibit high sorption capacities (0.35−0.74 normalgCO2 normalgsorbent−1 at 873 K) and are stable over multiple reaction‐regeneration cycles (<5% loss in initial capacity after 15+ cycles). X‐ray diffraction and scanning electron microscopy analysis reveal that thermally stable Al‐Ca mixed phases (Ca12Al14O33) mitigate crystallite agglomeration and maintain macroporous structures imparted by electrospinning. Nanofibers and Al‐doped nanofibers (Al:Ca ═ 2:10) exhibit more than a factor of three longer CO2 breakthrough time compared to CaO from marble (1650, 6400, and 7500 mL gsorbent−1 for CaO‐marble, 2Al‐10Ca‐O‐nanofibers, and CaO‐nanofibers respectively) under reforming conditions, with Al‐doped CaO‐nanofibers retaining 94% of their initial performance after ten reforming‐regeneration cycles, indicating their potential as improved sorbents for SE‐SMR processes.

Simulation of Sorbent-Enhanced Steam Methane Reforming and Limestone Calcination in Dual Turbulent Fluidized Bed Reactors

“…Previous studies have shown that in situ H 2 and CO 2 removal can favorably shift the thermodynamic equilibrium of the SMR reactions toward higher feedstock conversions. ,− In situ hydrogen removal can be achieved by inserting hydrogen perm-selective membranes (usually Pd-based) inside the reactor. Steam methane reforming can instead be integrated with calcium looping technology, with lime-based sorbents assisting in capturing high-temperature CO 2 and producing hydrogen. − …”

A novel technological blue hydrogen production process: industrial sorption enhanced autothermal membrane (ISEAM)

“…5 Hence, the deployment of an environmentally friendly and economically attractive process 6 with a low energy-penalty is of huge interest to researchers. Various research studies have been carried out to address the limitations of steam methane reforming (SMR) 7,8 which include Sorption Enhanced Reforming (SER), 9–29 Membrane Reforming (MR), 17,25,30–33 integrated Sorption Enhanced Membrane Reforming (SEMR) 34,35 and Gas Switching Reforming (GSR). Abanades et al 24,36–38 proposed the use of Ca/Cu looping in a single reactor through a three-step process; (a) sorption enhanced reforming with simultaneous carbonation of CaO; (b) oxidation of Cu to CuO with air; (c) calcination of CaCO 3 during the reduction of CuO with a fuel gas.…”

Comprehensive Investigation of Operating Parameters for Enhanced CO2 Capture Using CaO Sorbent and Machine Learning

“…Numerous experimental studies have been conducted to enhance the capture performance of CaO-based sorbents. These studies include high-temperature heat treatment, , hydration treatment, , development of synthetic high-specific-surface-area porous CaO-based materials, − and doping modification with other elements or oxides. − However, due to the limitations of time and resources, the number of experimental studies is limited. Simulation studies can bridge this gap and provide insights into the capture efficiency of sorbents under different conditions by using experimental data to establish a reaction kinetic model for the capture of CO 2 by CaO.…”