Improving the DME steam reforming catalyst by alkaline treatment of the HZSM-5 zeolite

Authors:  Jorge Vicente, Ana G. Gayubo, Javier Ereña, Andrés T. Aguayo, Martin Olazar, Javier Bilbao

Abstract:
Dimethyl ether (DME) steam reforming for hydrogen production has been studied on a bifunctional catalyst prepared by the (wet) physical mixing (at 50 wt%) of a metallic function of CuO–ZnO–Al₂O₃ (Cu/Zn/Al atomic ratio = 4.5:4.5:1.0, prepared by co-precipitation) and an acidic function of HZSM-5 zeolite modified by alkaline treatments of different severity. The runs have been carried out in a fluidized bed reactor. The results obtained by using treated HZSM-5 zeolites and γ-Al₂O₃ as acid functions have been compared. The alkaline treatment affects both the acid properties of the zeolite (attenuating total acidity and acid strength) and its porous structure (increasing the mesoporous surface and decreasing the microporous volume and BET surface area). The attenuation in acidity hinders the formation of undesired hydrocarbons from oxygenates (methanol + DME). Consequently, alkaline treatment (with 0.2–0.4 M NaOH solutions for 300 min) is suitable for improving the kinetic performance of the bifunctional catalyst, as it provides high selectivity and a high yield of H₂ at 300^◦C without hydrocarbon formation, as well as minimizing CO formation and avoiding deactivation by Cu sintering. The catalyst is stable, and its kinetic performance remains constant throughout long runs.

Keywords:
Dimethyl ether
Hydrogen
Steam reforming
HZSM-5 zeolite
Alkaline treatment

Published in: Applied Catalysis B: Environmental (Volumes 130–131, Pages 1-336, 7 February 2013)

Publisher: Elsevier  

ISSN Information: 0926-3373

Improving the DME steam reforming catalyst by alkaline treatment of the HZSM-5 zeolite

Bình luận của bạn

*

*

*

*

 Captcha

Gửi bình luận nhập lại