Experimental and modeling study of sorption enhanced catalytic methane reforming to pure hydrogen with in situ carbon dioxide capture

This paper presents an experimental and modeling investigation for a novel technique of low temperature high purity hydrogen production using sorption assisted catalytic methane reforming in a laboratory – scale fixed bed adsorptive reactor. The performance of methane steam reforming is experimentally tested over a newly developed catalyst – sorbent materials. Rh/CeaZr1-aO2 is employed as an efficient low temperature catalyst for steam reforming and autothermal reforming of methane. K-promoted hydrotalcites, Zr-doped K-promoted hydrotalcites, and lithium zirconate are employed as newly developed candidate sorbents for high purity hydrogen production at temperatures lower than 550oC. Experimental and modeled results are compared to the conventional Ni – based catalytic reforming processes. An enhanced methane conversion of 84%, which is the equilibrium conversion is attained using Hydrotalcites/Ni – based sorption enhanced autothermal reforming at operational conditions of 500oC, 4.47 bar, steam/carbon ratio of 6, oxygen/carbon ratio of 0.45 and space velocity of 3071 hr-1. The corresponding hydrogen yield and purity on dry basis are 3.6 and 95%, respectively. The lithium zirconate – based process demonstrated a gain of enhanced methane conversion of 99.5% and dry basis hydrogen purity of 99.5% achieved at the same conditions. The influence of major parameters of steam/carbon, oxygen/carbon, gas and catalyst temperatures, pressure, gas space velocity, and feed contamination is also examined.