Membrane reactor micro-reactors

Alternate PI configurations Hybrid separations Membrane reactors Micro-reactors... 

The values of the Michaelis-Menten kinetic parameters, Vj3 and C,PP characterise the kinetic expression for the micro-environment within the porous structure. Kinetic analyses of the immobilised lipase in the membrane reactor were performed because the kinetic parameters cannot be assumed to be the same values as for die native enzymes. 

Concerning function integration, for example, micro-flow membrane reactors can exhibit similar process intensification, as shown already for their large-scale counterparts [75]. Separation columns for proteomics, immobilizing enzymes, utilize the large surface-to-volume ratios. Surface tension differences can guide and transport liquids selectively. 

Figure 2.37 Temperature profiles across the membrane covering the reaction channel of the T micro reactor for a silicon and a silicon nitride membrane and two different heater designs, as discussed by Quiram et al. [128].

Reactor 10 [R 10] Catalyst Membrane Si-chip Micro Reactor with Sensing and Heating Functions... 

Figure 3.16 Schematic of Si-chip catalyst membrane micro reactor. Top view (A), end-on cross section of reaction channel (B) side-view cross section of reaction channel (C) [60].

Figure 3.17 Microfabrication sequence for the silicon component of the catalyst membrane micro reactor [57],...

Figure 3.28 Unexpected increase in NO/N2 selectivity for ammonia oxidation reaction in a micro membrane reactor [19],...

Figure 3.29 Ammonia oxidation over a Pt catalyst in different membrane micro reactors. Experimental results show good temperature uniformity across the catalyst regions [19].

Figure 3.30 Ignition/extinction loops for ammonia oxidation over platinum performed in micro reactors with different membranes [19],...

Membrane reactors can be considered passive or active according to whether the membrane plays the role of a simple physical barrier that retains the free enzyme molecules solubilized in the aqueous phase, or it acts as an immobilization matrix binding physically or chemically the enzyme molecules. Polymer- and ceramic-based micro- and ultrafiltration membranes are used, and particular attention has to be paid to the chemical compatibility between the solvent and the polymeric membranes. Careful, fine control of the transmembrane pressure during operation is also required in order to avoid phase breakthrough, a task that may sometimes prove difficult to perform, particularly when surface active materials are present or formed during biotransformahon. Sihcone-based dense-phase membranes have also been evaluated in whole-cell processes [55, 56], but... 

Franz et al. [93] developed a palladium membrane micro reactor for hydrogen separation based on MEMS technology, which incorporated integrated devices for heating and temperature measurement. The reactor consisted of two channels separated by the membrane, which was composed of three layers. Two of them, which were made of silicon nitride introduced by low-pressure chemical vapor deposition (0.3 pm thick) and silicon oxide by temperature treatment (0.2 pm thick), served as perforated supports for the palladium membrane. Both layers were deposited on a silicon wafer and subsequently removed from one side completely... 

Molten carbonate fuel cells Micro-electro-mechanical systems Microreactor Technology for Hydrogen and Electricity Micro-structured membranes for CO Clean-up Membrane reactor... 

Membrane technology has been performed using either micro-, ultra- or nanofiltration or reverse osmosis in either batch-wise or continuous-flow membrane reactors (CFMR). 

The development of a novel membrane reactor requires considerable effort, so a European consortium of universities, institutes and industry was formed. The complete consortium consists of seven partners including the University of Twente. The development of a new micro-... 

The first membrane reactor studies made use of dense metallic membranes, but due to certain limitations of these dense materials (sec below) and due to the rapid progress in the development of (micro)porous... 

This chapter gives an overview of the synthesis procedures and appUcations of zeoUte membranes (gas separation, pervaporation, zeolite-membrane reactors), as well as new emerging appUcations in the micro- and nanotechnology field. Related areas such as new zeoUte and zeoUte-related materials for membranes, alternative supports, and scale-up issues are also discussed. 

Tsuru, T., Yamaguchi, K., Yoshioka, T., and Asaeda, M. Methane steam reforming by micro-porous catalytic membrane reactors. AIChE Journal, 2004, 50 (11), 2794. 

Plant cells or tissues may be fermented like micro-organisms in the submerged fermenter if grown on the surface of carrier beads or are kept in suspension. There is also experience in the operation of special membrane reactors for this purpose [13]. 

Scaling up of the processes to large surface areas (i.e. to obtain asymmetric membrane systems with several layers) as is necessary for large-scale operations has been successfully demonstrated for micro/ultrafiltration and bioseparation processes, but not for other applications such as gas/vapour separation and membrane reactors, for which only small-scale laboratory equipment is available. 

O. Wolfrath, L. Kiwi-Minsker, A. Renken, Filamenteous catalytic beds for the design of membrane micro-reactor propane dehydrogenation as a case study, in M. Matlosz, W. Ehrfeld, J.P. Baselt (Eds.), Proceedings of the 5th International Conference on Microreaction Engineering (IMRET 5), Springer, Berlin, 2001, p. 191. 

In addition to the preparation of packed beds and monoliths, wall coating is an alternative method forthe introductionofcatalysts into continuous flow systems, due to the short diffusion distances obtained within micro reaction channels. An early example of this was demonstrated by Yeung and co-workers [59]. who employed a stainless-steel micro reactor [channel dimensions = 300 pm (width) x 600 pm (depth) x 2.5 cm (length)] coated with an NaA zeolite membrane, followed by a layer of... 

A third way to build up pFCs based on MEMS-polymers such as poly-dimethylsiloxane (PDMS) or polymethyl methacrylate (PMMA) or PCB-materials such as polyimid (PI) or FR4. These polymers can be micro-machined by molding or by laser ablation. Shah et al. [22,23] have developed a complete PEMFC system consisting of a PDMS substrate with micro-flow channels upon which the MEA was vertically stacked. PDMS micro-reactors were fabricated by employing micro-molding with a dry etched silicon master. The PDMS spin coated on micro-machined Si was then cured and peeled off from the master. The MEA employed consisted in a Nafion - 12 membrane where they have sputtered Pt through a Mylar mask. Despite an interesting method, this FC gave poor results, a power density of 0.8 mW cm was achieved. 

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