Modeling of sorption enhanced steam methane reforming in an adiabatic packed bed reactor using various CO₂ sorbents

A 1-D heterogeneous model of sorption-enhanced steam methane reforming (SE-SMR) process in a packed bed reactor consisting of nickel catalyst well mixed with CO₂ sorbent particles is investigated for three types of common sorbents. The performance of SE-SMR process is studied under low medium pressure conditions (3 – 11 bar) to find the optimum operating conditions. Optimal CaO sorption corresponding to 82% CH₄ conversion and 85% H₂ purity is found at 900 K, 3 bar, 3.5 kgm⁻²s⁻¹ and S/C of 3.0. In contrast, lithium zirconate (LZC) and hydrotalcite (HTC) sorbents exhibited best sorptions under the operating conditions of 773 K, 5 bar and S/C of 3 with CH₄ conversion of 91.3% and 55.2%, and H₂ purity of 94.1% and 77.8% respectively. In these conditions, the CH₄ conversion increased by 114%, 111% and 67% compared to the conventional SMR for the processes enhanced by HTC, LZC and CaO sorption respectively.