A novel catalyst-sorbent system for an efficient H2 production with in-situ CO2 capture

Abstract This paper presents an experimental investigation for an improved process of sorption-enhanced steam reforming of methane in an admixture fixed bed reactor. A highly active Rh/Ce α Zr 1−α O 2 catalyst and K 2 CO 3 -promoted hydrotalcite are utilized as novel catalyst/sorbent materials for an efficient H 2 production with in situ CO 2 capture at low temperature (450–500 °C). The process performance is demonstrated in response to temperature (400–500 °C), pressure (1.5–6.0 bar), and steam/carbon ratio (3–6). Thus, direct production of high H 2 purity and fuel conversion >99% is achieved with low level of carbon oxides impurities ( 4 conversion is obtained at a temperature of 450 °C and a pressure of 6 bar using a steam/carbon molar ratio of 4. The high catalyst activity of Rh yields an enhanced CH 4 conversion using much lower catalyst/sorbent bed composition and much smaller reactor size than Ni-based sorption enhanced processes at low temperature. The cyclic stability of the process is demonstrated over a series of 30 sorption/desorption cycles. The sorbent exhibited a stable performance in terms of the CO 2 working sorption capacity and the corresponding CH 4 conversion obtained in the sorption enhanced process. The process showed a good thermal stability in the temperature range of 400–500 °C. The effects of the sorbent regeneration time and the purge stream humidity on the achieved CH 4 conversion are also studied. Using steam purge is beneficial for high degree of CO 2 recovery from the sorbent.