Evaluation of CO₂ Hydrogenation in a Modular Fixed-Bed Reactor Prototype

• Main Authors: Heather D. Willauer, Matthew J. Bradley, Jeffrey W. Baldwin, Joseph J. Hartvigsen, Lyman Frost, James R. Morse, Felice DiMascio, Dennis R. Hardy, David J. Hasler
• Format: Article
• Language: English
• Published: MDPI AG 2020-08-01
• Series: Catalysts
• Subjects: carbon dioxide; hydrogenation; catalyst; gas hourly space velocity (GHSV); fixed-bed reactor
• Online Access: https://www.mdpi.com/2073-4344/10/9/970

Low-cost iron-based CO₂ hydrogenation catalysts have shown promise as a viable route to the production of value-added hydrocarbon building blocks. It is envisioned that these hydrocarbons will be used to augment industrial chemical processes and produce drop-in replacement operational fuel. To this end, the U.S. Naval Research Laboratory (NRL) has been designing, testing, modeling, and evaluating CO₂ hydrogenation catalysts in a laboratory-scale fixed-bed environment. To transition from the laboratory to a commercial process, the catalyst viability and performance must be evaluated at scale. The performance of a Macrolite^®-supported iron-based catalyst in a commercial-scale fixed-bed modular reactor prototype was evaluated under different reactor feed rates and product recycling conditions. CO₂ conversion increased from 26% to as high as 69% by recycling a portion of the product stream and CO selectivity was greatly reduced from 45% to 9% in favor of hydrocarbon production. In addition, the catalyst was successfully regenerated for optimum performance. Catalyst characterization by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), along with modeling and kinetic analysis, highlighted the potential challenges and benefits associated with scaling-up catalyst materials and processes for industrial implementation.