A theoretical comparison of multifunctional catalyst for sorption-enhanced reforming process. (21st August 2016)

• Record Type: Journal Article
• Authors: Lugo, Elva L.; Wilhite, Benjamin A.
• Is Part Of: Chemical engineering science. Volume 150(2016)
• Page Start: 1
• Page End: 15
• Publication Date: 2016-08-21
• Subjects: Sorption-enhanced reforming process -- Multifunctional catalyst -- CO2 sequestration -- Reaction-diffusion -- Dusty-gas-model; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; Chemical engineering; Periodicals; Electronic journals; 660
• DOI: 10.1016/j.ces.2016.04.011
• Languages: English
• ISSNs: 0009-2509

Abstract

Abstract: This work presents the first side-by-side comparison of the two leading multifunctional catalyst designs reported in the literature today for sorption-enhance reforming processes. Two-dimensional unsteady-state models were developed to compare the performance of a core–shell multifunctional catalyst, consisting of a calcium-based sorbent core enclosed in a porous shell of methane steam reforming or water-gas shift catalyst, against an equivalent case of a uniform-distributed multifunctional design in which catalyst and sorbent materials are uniformly distributed within the particle. Additionally, these two multifunctional catalyst designs were compared against the conventional two-pellet approach, where the capture and catalytic properties are distinguished into separate pellets. Both multifunctional catalyst designs (i.e. core-shell and uniform-distributed) had greater adsorbent utilization and higher H2 outlet concentration up to breakthrough time than the conventional two pellet design. The uniform-distributed multifunctional catalyst design had greater adsorbent utilization up to breakthrough conditions as compared to the core-shell design. This behavior may be attributed to the fact that for the uniform-distributed multifunctional, the active catalyst is constantly producing CO2 next to an adsorbent active site. For the core-shell multifunctional catalyst design, decreasing catalyst-shell thickness resulted in performance approaching the uniform-distributed case. For the case of exothermic water-gas shift reaction coupled with CO2 chemisorption, the core-shell design mitigated local bed hot-spot magnitudes by ~40 K. Highlights: Comparison of two one-pellet catalyst designs for sorption-enhanced processes. Both one-pellet designs had greater adsorbent utilization than a two-pellet design. Uniform-distributed design is recommended over core-shell due to better utilization. Core-shell design approaches uniform-distributed results at low catalyst thicknesses. Core-shell design mitigates hot-spot for an adiabatic sorption-enhanced WGS process.