Membrane microreactors

Inorganic Membrane Reactors Fundamentals and Applications First Edition. Xiaoyao Tan and Kang Li. 2015 John Wiley Sons, Ltd. Published 2015 by John Wiley 8c Sons, Ltd. 

Since the membranes incorporated in MMRs are zeolite or dense metal ones, which have been described extensively in previous chapters, this chapter focuses mainly on the general structure, design, and fabrication of MMRs and their applications. The recent advances and future trends of MMR technology are also given. 

A distinctive feature of microreactors is the microchannels for fluid flow. MMRs are mainly characteristic of such microchannels with anchored catalysts for reactions and miniature membranes to perform separation, which are formed on the porous ceramic or metal supports. Based on the configuration and architecture of the reactor, MMRs can be classified into two categories plate type and tubular type. 

or ceramic membranes formed within a microchannel can be used also as a catalyst support [98]. The most of the demonstrated reactions involved two liquid phases and separated aqueous from an organic phase. 

Nitrite reduction in water is tested as a model reaction. It is shown that nitrite reduction proceeds by both catalytic reduction (with Pd and H2) and by the reactor material itself (i.e., by Fe on CNFs). Eventually, the latter effect will exhaust in time and the reaction will still proceed with the immobilized Pd-catalyst on the CN Fs and the membrane-assisted supply of hydrogen. Results proved that the porous metallic membrane microreactors with carbon nanofibers are suitable materials for the reduction of nitrite and the reactor design is very promising for the multiphase microreactor technologies [lOOj. 

A high-throughput tube-in-tube microchannel reactor was recently designed and developed as a novel gas-liquid contactor [102,103]. 

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Mixet/vaporizet Catalytic reformer membrane microreactor... 

Lai SM, Ng CP, Martin-Aranda R, and Yeung KL. Knoevenagel condensation reaction in zeohte membrane microreactor. Micropor Mesopor Mater 2003 66(2-3) 239-252. 

Yeung KL, Zhang X, Lau WN, and Martin-Aranda R. Experiments and modeling of membrane microreactors. Catal. Today 2005 110 26-37. 

Lai SM, Martin-Aranda R, Yeung KL (2003) Knoevenagel condensation reaction in a membrane microreactor. Chem Commun 22 218-219... 

Another silicon membrane microreactor, composed of an aluminum bottom plate, a microstructured silicon layer carrying the channel system, and a 3 pm thick SiN membrane as a cover of the reactor, was developed [60]. Pt as an active component was put on the membrane either by wet chemistry or by PVD on a Ti adhesion layer. The reactor was manufactured by photolithography and plasma etching. The channels were introduced either by wet-etching or deep reactive ion etching. By increasing the thickness of the membrane from 1 to 1.5 and 2.6 pm. 

Figure 6.14 Membrane microreactor designed. (Adapted from Ref. [67].)...

Alfadhel, K. and Kothare, M.V. (2005) Modeling of multicomponent concentration profiles in membrane microreactors. Industrial Engineering Chemistry Research, 44 (26), 9794-9804. 

Abstract Process intensification (PI) is the future direction for the chemical and process industries and in this chapter, two key technologies to achieve this are discussed microreactors and so-caUed membrane microreactors (MMRs).There is great potential to enhance the overall efficiency of microreactors by integrating them with membrane technologies to make MMRs and there are tremendous opportunities for the application of MMRs in many fields. This chapter reviews microreactor design, fabrication and apphcations as well as materials for micromembranes (MM). The integration of MMs with microreactors and the applications of the resulting MMRs are then discussed. 

Key words membrane microreactor, microfluidic device, palladium... 

Membrane microreactor Fabrication methods Thickness (nm) Reaction Temperature (°C) Catalyst Membrane function References... 

Scheme for membrane microreactors for multiphase reactions, that is, gas-liquid reactions (left), a PSS supported dense PDMS gas-permeable membrane with CNFs as a catalyst support (right). (Aran eta ., 2011) (Copyright permission 2011 Elsevier). 

Product yield as a function of residence time for a fixed-bed reactor (triangles), a multi-channel microreactor (circles) and a multi-channel membrane microreactor (squares) (Lai etal., 2003) (Copyright permission 2006 Royal Society of Chemistry). 

Aran H C, Benito S P, Luiten-OliemanMW J,Er S,Wessling M,Lefferts L,BenesN E and Lammertink R G H (2011), Carbon nanofibers in catalytic membrane microreactors , J Membrane Sci, 381,244-250. 

Goto S,TagawaT, Assabumrungrat S and PraserthdamP (2003), Simulation of membrane microreactor for fuel cell with methane feed , Catal Today, 82,223-232. 

Lau W N, Yeung K L, Zhang X F and Martin-Arand R (2007), Zeolite membrane microreactors and their performance , Stud Surf Sci Catal, 170,1460-1465. 

Takahashi T, Tanaka S, Chang K S and Esashi M (2005), In-situ chemical vapor deposition of alumina catalyst bed on a suspended membrane microreactor , Solid-State Sensors, Actuators and Microsystems, TRANSDUCERS 05. The 13th International Conference, 1,899-903. 

Ye S Y, Tanaka S, Esashi M, Hamakawa S, Hanaoka T and Miznkami F (2006), MEMS-based thin palladium membrane microreactors , Proc SPIE, 6032, 603207. 

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