This article critically reviews the literature on iron-based catalysts for the high-temperature water–gas shift (HT-WGS) reaction. The reaction mechanism, reaction intermediates, rate-determining step, kinetics, active site, and promoters are covered. Unlike the low-temperature water–gas shift (LT-WGS) reaction by Cu/ZnO catalysts that has received intensive analysis with modern in situ and operando spectroscopy and DFT studies, the corresponding HT-WGS reaction by Fe-based catalysts still lacks a fundamental understanding because of the absence of modern catalysis studies of this important catalytic system. Given the role of the WGS catalysts on production of H2 for a hydrogen economy, it is imperative that the fundamental molecular-level understanding of the HT-WGS catalyst be advanced.

Iron-Based Catalysts for the High-Temperature Water–Gas Shift (HT-WGS) Reaction: A Review

Water gas shift reaction for hydrogen production and carbon dioxide capture: A review

Adsorption equilibria and kinetics of six pure gases on pelletized zeolite 13X up to 1.0 MPa: CO2, CO, N2, CH4, Ar and H2

Future prospects for production of methanol and hydrogen from biomass

An evaluation of hydrogen production from the perspective of using blast furnace gas and coke oven gas as feedstocks

The world’s progression towards the Hydrogen economy is facilitating the production of hydrogen from various resources. In the carbon based hydrogen production, Water gas shift reaction is the intermediate step used for hydrogen enrichment and CO reduction in the synthesis gas. This paper makes a critical review of the developments in the modeling approaches of the reaction for use in designing and simulating the water gas shift reactor. Considering the fact that the rate of the reaction is dependent on various parameters including the composition of the catalyst, the active surface and structure of the catalyst, the size of the catalyst, age of the catalyst, its operating temperature and pressure and the composition of the gases, it is difficult to narrow down the expression for the shift reaction. With different authors conducting experiments still to validate the kinetic expressions for the shift reaction, continuous research on different composition and new catalysts are also reported periodically. Moreover the commercial catalyst manufacturers seldom provide information on the catalyst. This makes the task of designers difficult to model the shift reaction. This review provides a consolidated listing of the various important kinetic expressions published for both the high temperature and the low temperature water gas shift reaction along with the details of the catalysts and the operating conditions at which they have been validated.

A Review of the Water Gas Shift Reaction Kinetics

The world is bound to make a gradual shift from Hydrocarbon Economy towards the Hydrogen Economy. This shift is being facilitated by the technological development in Hydrogen energy that is occurring around the world. Gasification of Biomass for generating Biomass Synthesis Gas is a promising source for the distributed power generation concept as it is based on the local raw material supply. This concept has to be augmented by hydrogen fuel cell technology for modular, efficient and environmentally benign implementation. This provides the platform for looking at the option of separating Hydrogen from Biomass Synthesis gas which is composed of H2, N2, CO, CO2, CH4, Tar, alkali traces and particulate matter at varying compositions depending on the Biomass and operating conditions. This paper makes a critical review of the attempts made to reform and separate Hydrogen through a Hydrogen Permeable Membrane Reformer Reactor as it provides the energy efficient route. The feasibility and various membranes from Palladium to ceramic membranes used in the reactor configurations and the engineering problems of the reactor will be analyzed. The inherent problems in providing a one shot modular solution for solving the problem will be discussed in the paper.

Membrane Reactor Based Hydrogen Separation from Biomass Gas -- A Review of Technical Advancements and Prospects

Membrane reactor is a process intensified equipment that carries out both the reaction and separation in a single vessel. The equilibrium limited water gas shift reaction is an ideal reaction to be carried out in a membrane reactor as it improves the conversion of the reaction and reduces the space requirement for the reactor. Computational fluid dynamics offers a virtual prototyping of the reactor and helps in design, optimization, and scale-up of the reactor. To obtain pure hydrogen from the membrane reactor, the pressure of the reactor needs to be optimized. Hence the water gas shift membrane reactor is subjected to computational fluid dynamic analysis to understand the role played by pressure on the performance of the reactor using three different gas mixtures. The CO conversion and H2 recovery for the different operating pressures are simulated and the effects of pressure are discussed in this paper.

Murthy Shekhar Shantha

Papers

A Review of the Water Gas Shift Reaction Kinetics

Membrane Reactor Based Hydrogen Separation from Biomass Gas -- A Review of Technical Advancements and Prospects

CFD Simulation of Water Gas Shift Membrane Reactor--Pressure Effects on the Performance of the Reactor