(560er) Long-Term Stability of Modified Ferrite Catalysts for High-Temperature Water-Gas Shift Reaction at Elevated Pressures

Devaiah Dammaand Panagiotis G. Smirniotis*

Chemical Engineering, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, OH 45221-0012, USA

*panagiotis.smirniotis@uc.edu (P.G. Smirniotis)

The water gas shift (WGS) reaction is an important operation for H₂ production from the CO-rich gas stream (synthesis gas) that generated from fossil fuels, agricultural and forestry biomass, and municipal wastes via the gasification route. Especially, the high temperature and high-pressure WGS reaction in a single stage catalytic membrane reactor is a promising technology because of the advantages of faster reaction rate and enhanced H₂ transport through the membrane that is necessary to obtain complete CO-conversion and total H₂ recovery. Industrially, Fe–Cr-based spinels had been proven to be a promising catalyst for HT-WGS. However, excess steam (H₂O/CO ≈ 5) is used in the industry to maintain the catalyst stability by preventing over-reduction of the catalyst and suppressing side reactions (methane formation). Therefore, the commercial catalyst could not be suitable for the WGS reaction based on gasification process because of the presence of CO-rich gas in the reactant stream that leads to catalyst deactivation. In this context, some catalysts have been developed to satisfy the requirements for the HT-WGS reaction using gasification-derived synthesis gas. However, most of the reported catalysts tested at atmospheric conditions, which is not representative for the industrial application (20–30 bar) regarding deactivation of the catalyst and side product formation (especially methane). Development of catalysts at high pressures and temperatures can meet the stringent requirements of membrane reactors operating conditions. The present study is aimed at developing the catalysts for HT-WGS at elevated pressures which represent the membrane reactor conditions. For this purpose, we have reported various modified ferrite catalysts prepared by co-precipitation method for WGS at elevated pressures and high temperatures. Our catalysts showed a stable performance in terms of CO conversion without significant loss in the activity for a long period of time. Generally, methanation reaction can cause the catalyst deactivation during the WGS reaction at elevated pressures. Interestingly, no significant formation of methane was observed in the present investigation. The catalysts in fresh and spent states were also characterized by using various structural and surface techniques in order to establish structure-activity relationships. These interesting results will be discussed in the presentation.