Steam methane reforming reaction enhanced by a novel K2CO3-Doped Li4SiO4 sorbent: Investigations on the sorbent and catalyst coupling behaviors and sorbent regeneration strategy

• A novel sorbent was evaluated under the steam and low CO2 concentration conditions.
• Different sorbent-catalyst coupling methods were discussed in SE-SMR system.
• High-purity H2 and low CO concentration can be obtained at low temperatures.
• A reasonable sorbent regeneration strategy was proposed to simplify the process.
• Steam increased the sorbent regeneration rate and can keep the system stable.

A homemade K2CO3-doped Li4SiO4 sorbent was applied into the sorption-enhanced steam methane reforming (SE-SMR) system. Both the activated K2CO3-doped Li4SiO4 sorbent and the Ni/γ-Al2O3 catalyst showed good activity and stability. The result shows that the application of the activated K2CO3-doped Li4SiO4 sorbent into SMR system can remarkably enhance the process. High-purity hydrogen (H2 yield >95%) was obtained at relatively low temperatures (500–550 °C), which was 100–150 °C lower than that of using the calcium-based sorbents. Furthermore, the effects of different absorbent-catalyst coupling methods and particle sizes on the reactant diffusion were also discussed, finding that in-situ enhancement and moderate particle sizes (20–40 mesh) were beneficial for the reaction system. Finally, a reasonable sorbent regeneration strategy was proposed. It is found that steam enhances the regeneration rate of sorbent and has little negative effects on the activity of sorbent and catalyst, which makes it possible to obtain high-purity CO2 directly and simplify the subsequent separation process for the sorption-desorption operation design.