Catalytic Membrane Reactors – Chemical Upgrading and Pollution Control

Abstract

This article presents an overview on oxygen permeation, oxidative activation of light hydrocarbons and splitting of various molecules (H 2 O, N 2 O, NO x ) containing oxygen in a hollow fiber catalytic membrane reactor made of BaCo x Fe y Zr z O 3-d (BCFZ, x+y+z = 1) which is used to separate oxygen from oxygen containing gases. Innovative reactor concepts are introduced and performances for the various applications are discussed. A detailed view is also given on the thermodynamic and kinetic background with regard to the above mentioned reactions. The potentials in terms of product intensification and energy saving by usage of the BCFZ hollow fibers as reaction vessels are evaluated. However, there are still technological challenges that prevent the described processes from being practiced on commercial scale by now.

Membrane Reactors: Advanced Systems for Intensified Chemical Processes

“…Perovskites membranes with the composition BaCo x-Fe y Zr z O 3-δ (BCFZ, x + y + z = 1) have showed outstanding properties for selective oxygen permeation and have been used in numerous lab-scale membrane reactor investigations, where they achieved several advantages in comparison to traditional reactors [19]. An interesting example is the improvment of NO x (x = 1 or 2) conversion by selective oxygen removal in a perovskyte catalytic membrane extractor.…”

“…Perovskite membranes have been used for oxygen distribution to a reaction mixture in oxidative coupling of methane (OCM) to C 2 products [19,30]. In the membrane reactor, a BCFZ hollow fiber was combined with a silicasupported Mn/Na 2 WO 4 catalyst as a packed bed around the fiber (Fig.…”

Direct Conversion of Methane to C2Hydrocarbons in Solid-State Membrane Reactors at High Temperatures

“…For example, high rates of O 2 in the feed of the OCM reactor lead to the total combustion of CH 4 and C 2 products, forming CO and CO 2 . Other practical issues such as the buildup of hot spots in the exothermic OCM process and the risk of explosions also hinder the design of large-scale reactors, whereas in the NOCM process, it would be interesting to constantly remove the hydrogen formed to shift the thermodynamic equilibrium to the formation of C 2 products and to avoid subsequent hydrogenation reactions. ,,− ,− …”