Hybrid catalytic materials with CO2 capture and oxygen transfer functionalities for high–purity H2 production

Abstract

In this work, we report the development and performance evaluation of hybrid, multifunctional catalytic materials based on NiO and CaO for the Sorption Enhanced Chemical Looping Steam Methane Reforming process (SE–CL–SMR). The multifunctional materials with various NiO/CaO/inert ratios were prepared via the sol–gel auto–combustion method. Testing under SE–CL–SMR conditions was conducted in a fixed bed reactor unit. High CH4 conversion is achieved over all developed materials, resulting in the production of high–purity hydrogen (> 95 %) at 650 °C and steam/carbon ratio of 3. Compared to a mixed bed of sorbent and oxygen transfer material (OTM), operation with the multifunctional material allows for more efficient use of the heat generated by Ni reoxidation during regeneration due to the direct heat transfer between the OTM and sorbent phases. Although higher NiO and CaO content in the hybrid material translates to greater loss of autothermicity during regeneration with increasing number of cycles, the decrease of the inert fraction reduces up to ∼25 % the volume of the bed compared to the respective sorbent/OTM mixture. Such an outcome clearly demonstrates the benefit of using a multifunctional material for the intensified SE–CL–SMR process.