## 1 Introduction
Among the opportunities for the development of sustainable blue hydrogen production, sorption-enhanced steam methane reforming (SE-SMR) is an advanced technology in which the reforming and CO\({}_{2}\) separation steps are integrated in a single reactor. The concept of sorption-enhanced reaction for hydrogen production was proposed by [PERSON] et al. [8] to shift the equilibrium of the reaction towards a higher hydrogen production by simultaneously removing the produced CO\({}_{2}\) using a proper solid sorbent, according to [PERSON]'s principle. The steam reforming and CO\({}_{2}\) removal reactions occur in the reformer/adsorber in the presence of a catalyst and a sorbent. The sorbent is then regenerated in another reactor [2]. This technology leads to a more compact (two-in-one) process unit with the reduction of operational complexity and, thus, of capital cost (CAPEX), improving hydrogen yield at a lower cost of gas post-processing compared with traditional hydrogen production technologies such as SMR. Furthermore, quite moderate operating conditions, even up to 450-490 \({}^{\circ}\)C, 180-890 kPa, with the production of a gas stream with 90-98% hydrogen, can be applied, potentially decreasing operational expenses (OPEX) [1]. Overall, when considering blue hydrogen, SE-SMR presents, when compared with SMR combined with commercial CCS technologies, higher yields of H2 and conversions of methane as well as lower reforming temperatures, with no multiple shift reactors and subsequent purification steps. The main challenge of SE-SMR technology lies in the energy-intensive sorbent regeneration processes, such as oxyfuel combustion or indirect heating, required to sustain calcination without emitting CO2 into the atmosphere. Several integrated solutions are studied for decarbonized and high-purity hydrogen production with reduced energy penalties and CO2 emissions from the regeneration of the CO2 sorbent [9]. The configurations studied for SE-SMR, both experimentally and by means of modeling, include trickle beds [10], fixed beds, which are focused mainly on the development of highly performing sorbent materials [11; 12], and fluidized bed reactors, known to be favorable for large-scale continuous operation [13; 14; 15; 16; 17]. In these investigations, the reforming and water-gas shift reactions occurred together with the in situ CO2 sorption reaction at temperatures ranging between 550 \({}^{\circ}\)C and 650 \({}^{\circ}\)C and generally under atmospheric conditions. On the other hand, CFD (1-D, 2-D and 3-D) is the most adopted tool for modeling SE-SMR in fluidized bed reactors [2]. Fluidized bed experimental studies involved lab-scale reactors operated in the bubbling regime, with mostly traditional catalysts and natural dolomites as sorbents, showing the expected reduction in sorption capacity with an increasing number of carbonation-calcination cycles. The distinct operating conditions of the reforming and regeneration stages make it favorable for the two stages to operate in different reactors to ensure the continuous production of hydrogen by periodically regenerating the sorbent, with an important impact on the final design of the SE-SMR system in a potential scale-up to commercial size. When considering fixed bed configurations, whose advantages include compact design and easier operability at high pressures, batteries of several fixed beds are required, alternating their operation between reforming and regeneration, to overcome their discontinuous operation. On the other hand, for fluidized beds presenting good gas-solid contact and better heat management, the solution of interconnected fluidized beds is widely studied, enabling the continuous solids looping between the reactors. In the literature it is reported that, under specific operating conditions, a hydrogen concentration ranging from 96 to 99 vol% on a dry basis can be obtained [2; 14; 15].