Modelling and design of a novel calcination reactor integrated with a CO2 capture process for intensified hydrogen production

Sorption enhanced steam methane reforming (SE-SMR) is an advantageous process for the production of H2 and simultaneous CO2 capture with solid sorbents. Aiming at implementing a continuous SE-SMR process, it is necessary to foresee a regeneration step of the sorbent via its calcination, to make it available for further CO2 capture in the reforming reactor. This work focused on the design of a calcination reactor for the regeneration of a dolomite sorbent to couple with a methane reformer/carbonation reactor. Calcium carbonate (CaCO3) calcination in CO2 atmosphere was studied via thermo-gravimetric analysis (TGA) using naturally occurring dolomite, and kinetic parameters were extrapolated (pre-exponential factor Aapp = 6.28 E+25 s−1 and activation energy Eapp = 6.41 E+5 J/mol). A preliminary design of the calciner was defined and its performance was investigated with Computational Particle-Fluid Dynamics (CPFD) simulations. A first preliminary Geometry 1 showed some limitations in the CaCO3 conversion, due to insufficient particle residence time. An optimized Geometry 2 was developed with an internal tube (jacket tube) acting as obstacle for increasing the average residence time of the particles. A further simulation of this new geometry showed higher residence time and increased conversion rate of approximately 95% after 220 s of simulation.