Recent advances on materials and processes for intensified production of blue hydrogen

Steam reforming of natural gas is the dominant process for large-scale hydrogen production. The process is characterized by high energy requirements and high carbon footprint due to the high endothermicity of the reforming reaction and the harsh operating conditions applied (high temperature, in the range of 800-900 ? and pressure of 20-30 atm). The necessity for a cost-effective and competitive hydrogen production process has spurred the interest towards the development of alternative reforming routes. In view of the above, considerable research efforts have been directed in the past years to the development of novel reforming concepts such as Chemical Looping Reforming (CLR) and Sorption Enhanced Reforming (SER). These alternatives target towards reduction of energy requirements of the steam reforming and/or in-situ separation of one of the products (CO2), leading to significant process intensification. The work performed on the development of the aforementioned concepts for intensified blue hydrogen production, the required materials and the strategies followed to improve their performance are critically reviewed in this paper. Moreover, research efforts targeting the development of hybrid processes that combine the advantages of the standalone, intensified concepts are also discussed.