The review of Cr-free Fe-based catalysts for high-temperature water-gas shift reactions

High-temperature Water–Gas Shift catalysts for hydrogen enrichment of a gas produced by biomass steam gasification

“…No CH 4 formation was observed and the carbon formed on the foam (carbon balance lower than 100%) was probably oxidized by the excess of water permitting a 4-h duration test. These a. results are in accordance with those obtained by Lee et al [31] who observed an increase in CO conversion with an increase in the H 2 O/CO ratio. The results obtained are not close to the thermodynamic values due to the very low residence time imposed by the reactor size at the pilot scale.…”

“…þP H 2 0 [31]. Kahn et al [32] defined an optimal R factor of 1.4 to reach a CO conversion of 79% at 550 8C (thermodynamic CO conversion 93%).…”

Kinetics of the high temperature water–gas shift over Fe2O3/ZrO2, Rh/ZrO2 and Rh/Fe2O3/ZrO2

“…Recently, from industry [4] and academia [5,6] work is reported to develop chromium-free high temperature shift catalysts because of environmental and health hazards to handle chromium. In a previous study we reported chromiumfree Rh/Fe 2 O 3 /ZrO 2 as a highly active catalyst under realistic WGS conditions with better performance than a commercial catalyst, although with formation of some side product methane (<1000 ppm) [7].…”

Promotion of the Water‐Gas‐Shift Reaction by Nickel Hydroxyl Species in Partially Reduced Nickel‐Containing Phyllosilicate Catalysts

“…To strike ab alance between the kinetics and thermodynamics, this reaction is industrially operated in two stages:o ne at lower temperatures ( % 200-250 8C) catalyzed by Cu-Zn catalysts;t he other at higher temperatures ( % 350-450 8C) catalyzed by Fe-Cr catalysts. [1][2][3][4] In the high-temperature WGS reaction, Ni is widely studied as ac andidate to replaceF e-Cr catalysts, whicha re known to be toxic owing to theC rc ontent. [5] Despite the high catalytic activity of Ni at high temperatures, it catalyzes the undesirable methanation side reaction, which decreasest he H 2 selectivity and hinders the commercialization of Ni-basedc atalysts.…”