Inorganic Membranes for Process Intensification: Challenges and Perspective

Abstract

Membrane separators and reactors represent some of the most interesting options for process identification and modularization. In spite of intensive research and significant progress in material development and understanding of fundamentals of membrane properties and membrane processes, commercialization of inorganic membrane separation and reaction processes remains a big challenge. This paper summarizes important separation/permeation properties of several groups of inorganic membranes for molecular separation and discusses key hurdles in commercializing inorganic membrane separators and reactors for process intensification. Future research and development efforts should be focused on addressing these key hurdles including synthesis of membranes with higher permeance and stability, fabrication of low cost and high packing density membrane substrates, and development of cost-effective, scalable methods for synthesis of a membrane separation layer. Commercial applications of highly permeable water-selective zeolite membrane separation processes will be expanded to membrane reactors coupling reaction with the removal of water from the membrane reactor.

Ultrafast Semi‐Solid Processing of Highly Durable ZIF‐8 Membranes for Propylene/Propane Separation

“…Most of the reported performance have already met the industrial application requirements, i.e., C 3 H 6 permeability higher than 1 Barrer and C 3 H 6 /C 3 H 8 selectivity higher than 35 [20] . Nevertheless, there are still several challenges remaining to be overcome towards industrial applications, including reduction of membrane cost, improvement of process reproducibility, long‐term membrane durability, and more importantly, modularization with high packing density [21] …”

“…[20] Nevertheless, there are still several challenges remaining to be overcome towards industrial applications, including reduction of membrane cost, improvement of process reproducibility, long-term membrane durability, and more importantly, modularization with high packing density. [21] Herein, we report a reliable and scalable semi-solid processing approach, i.e., dip coating-thermal conversion (DCTC) method (Figure 1 a) for the fabrication of ZIF-8 membranes. The precursor solution was prepared by dissolving stoichiometric metal and ligand in H 2 O/DMAc (dimethylacetamide) mixed solvent.…”

Membranes for olefin–paraffin separation: An industrial perspective

“…The main advantage of inorganic membranes compared to other types of membranes is their thermal and chemical resistance along with high gas separation performance, which makes them an attractive choice for petrochemical separations. Two types of inorganic porous membranes that were studied extensively for petrochemical applications are zeolites an MOFs (42). Porous materials showed great potential for petrochemical separations because of their high gas fluxes compared to nonporous materials while having desirable selectivity due to their rigid and uniform pore structures in the range of molecular dimensions.…”

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

“…cat ⇔ H 2 + CO 2 , ∆H o r = − 41.2 kJ/mol (1) For the past decades, the concept of high-temperature H 2 -permselective WGS membrane reactor (MR) has attracted tremendous interest because of its capability to overcome the limit of equilibrium conversion by instantaneously separating and removing the H 2 product from the catalyst bed during reaction. The H 2 -permselective WGS MRs are thus widely viewed as a promising means to lower costs of H 2 production with simultaneous CO 2 separation and capture because they enable significant process intensification and simplification for the reduction of energy consumption and capital cost [1].…”

“…The water gas shift (WGS) reaction is a key operation in the industrial production of hydrogen from fossil fuel and biomass or biogas-derived syngas. The reaction, as expressed by Equation (1), is moderately exothermic and reversible. The WGS reaction rate is enhanced but the equilibrium CO conversion is lowered when increasing reaction temperature.…”