Feasibility of CaO/CuO/NiO sorption-enhanced steam methane reforming integrated with solid-oxide fuel cell for near-zero-CO2 emissions cogeneration system

Abstract In this article, a process for sorption-enhanced steam methane reforming in an adiabatic fixed-bed reactor coupled with a solid oxide fuel cell (SOFC) is evaluated using a 1D numerical reactor model combined with a simplified fuel cell simulation. A novel material comprising CaO/CuO/Al 2 O 3 (NiO) pellets is considered. Three operating stages are considered in the proposed system, namely (i) CaO carbonation/reforming, (ii) Cu and Ni oxidation, and (iii) CaCO 3 calcination/CuO and NiO reduction. The operating conditions that enable cyclic operation of these stages and the strategy needed to switch between each stage are evaluated. Under the adopted control strategy, methane conversion was about 95%, whilst H 2 yield and purity were around 3.2 mol H2  mol CH4 −1 and 90%, respectively. Moreover, a concentrated CO 2 stream ready for storage was obtained. By using a portion of the produced H 2 to make the process self-sufficient from an energy standpoint, an equivalent H 2 yield and a reforming efficiency of about 2.8 mol H2  mol CH4 −1 and 84% were achieved, respectively. With respect to SOFC integration, net power and thermal energy generation of around 11 kW and 6 kW, respectively, can be achieved. With respect to the chemical energy of the inlet methane, the net electrical and thermal efficiencies of the considered process are 56% and 30%, respectively, i.e. , the overall efficiency of the entire system is 86%. The proposed cogeneration system showed better thermodynamic, environmental and economic performances than those of conventional systems, with an investment pay-back period of 2.2 years in the worst-case scenario. The levelised cost of electricity, of heat and total power were about 0.096 € kW h −1 , 0.19 € kW h −1 , and 0.065 € kW h −1 , respectively, while the CO 2 emissions were avoided at no cost.