Recent Advances in Structured Catalysts Preparation and Use in Water-Gas Shift Reaction

Abstract

The water-gas shift reaction plays a key role in hydrogen production processes from fossil sources and renewable biomass feedstock and can be considered as the first purification process of syngas. The water gas shift process is normally carried out in two adiabatic stages, of high and low temperature with an intersystem cooling. The two stages use two different catalytic systems, which present some critical issues, thus making extremely attractive the designing and implementing of new configurations. Innovative and highly active catalytic formulations along with more efficient reactor systems could provide the basis for the design of a single-stage process, resulting in a noticeable process intensification. In the last decades, much attention has been paid to the use of structured catalysts, which have numerous advantages, related to both fluid dynamics and heat transfer phenomena. Numerous papers have been published in which the competitive performances of structured catalysts have been shown with respect to conventional catalytic systems. In this brief review, we provide an overview of the most recent developments in the preparation of structured catalysts and use in the water gas shift reaction.

Recent Advances in the Development of Highly Conductive Structured Supports for the Intensification of Non-adiabatic Gas-Solid Catalytic Processes: The Methane Steam Reforming Case Study

“…Thus, activation strategies are required to disperse effectively the catalytic active phase on the surface of the supports. Among others, electrochemical deposition, spray-based techniques, chemical vapor deposition (CVD) and slurry coating have been extensively studied and reported in recent reviews (Mehla et al, 2019;Palma et al, 2019).…”

Main Hydrogen Production Processes: An Overview

“…In addition to carbon monoxide and hydrogen, in the gas stream at the outlet of the reformer, unreacted methane and carbon dioxide are also present, therefore, further treatment/purification steps are necessary for obtaining pure hydrogen. In particular, one [15] or two stages of CO-water gas shift [16,17] followed by selective methanation [18], preferential oxidation [19] or a treatment with permselective membranes [20]. Although noble metal-based catalysts provide high activity and good stability, the high cost and the limited availability of the noble metals prevent their use, so Ni/Al 2 O 3 is the most used commercial catalyst for MSR [21].…”

Carbon Nanotube Formation on Cr-Doped Ferrite Catalyst during Water Gas Shift Membrane Reaction: Mechanistic Implications and Extended Studies on Dry Gas Conversions

“…The pre-membrane catalyst bed, which converts a significant amount of CO before entering the membrane section, is necessary for membranes of moderate α H2/CO to lower the reaction side CO partial pressure at the beginning of the membrane for preventing excessive permeation of unreacted CO. The WGS and dry gas reactions are exothermic overall, which may cause temperature increases to induce instability and affect reactor performance [41]. However, the small ceramic tube reactor, because of the large stainless steel housing and minimal amount of catalyst used, was able to stabilize the operation, with the exiting gas temperature increases being limited to <10 • C. The catalyst was activated after being packed in the MR by partial reduction at 400 °C for 4 h in a process gas flow containing 33.3% CO, 25.0% CO2, 25.0% H2, and 16.7% H2O [4].…”