Modelling of a continuous sorption-enhanced methanation process in an adiabatic packed-bed reactor system

• Sorption-enhanced methanation in a Ni-13X zeolite packed beds network was modelled. • Autothermal continuous operation of the proposed system can be achieved. • High purity (Y CH4 > 99 %) methane stream can be produced under optimal conditions. • For any given GHVS value, an increase in operating pressure increases methane purity. The present study investigates a sorption-enhanced methanation process and successive solid regeneration stages using a dual-function catalyst containing nickel as a catalyst and zeolite 13X for water removal. An adiabatic packed bed, modelled by a dynamical and heterogeneous model, has been considered, and a five-stage sequence describes the sorption-enhanced methanation and successive solid regeneration. First, methanation occurs with in-situ water removal; then, the catalyst drying using a pressure and temperature swing approach implemented by blowdown, purge, cooling, and pressurisation stages. In adiabatic operation, heat management is crucial; on the other hand, the heat produced can be efficiently used to dry the zeolite. Process intensification is pursued by addressing the effect of gas inlet temperature, pressure, and GHSV on system performance. Achieving an average purity of 99 % of the methane for pressures greater than 2 bar is possible for long-time operation, with productivity averaging 0.8 mol/(kg ads min) at the highest gas hourly space velocity investigated.