(644d) High-Purity Hydrogen Production at Lower Temperatures Via Sorption-Enhanced Steam Methane Reforming Using a Novel K-Doped Li4SiO4 with High-Purity CO2 Generation during Desorption Process

In this work, a novel K-doped Li₄SiO₄ sorbent with high capacity was applied to sorption-enhanced steam methane reforming (SE-SMR) system, and its enhancement for the steam methane reforming (SMR) reaction was investigated under various conditions. Since large amount of steam exists in the SE-SMR system, it is necessary to discuss the effects of steam on the sorbent’s sorption ability and stability first. It is found that steam can increase sorbent’s sorption ability and sorbent also shows good stability in the humidity atmosphere. When applying the novel K-doped Li₄SiO₄ to the SE-SMR system, the chemical equilibrium was broken and the SMR reaction was dramatically enhanced in the temperature range of 450°C-650°C. In particular, H₂ yield was enhanced from 78% in the SMR system to more than 95% in the SE-SMR system at 550°C. Traditional desorption method by purging N₂ at high temperatures needs further separation to obtain high-purity CO₂, therefore, a novel method by purging steam to obtain high-purity CO₂ using one-single step was proposed and studied in this work. The desorption ability of N₂ and steam was firstly compared and the results showed that the desorption rate of steam was much faster than that of the desorption rate of N₂. Furthermore, both the catalyst and K-doped Li₄SiO₄ sorbent present good stability, indicating its good application prospect in hydrogen production at relativitely lower temperatures.