Tubular membranes reactors

Using an approach involving a tubular membrane reactor in which the biocatalysts were retained, Nasufi et al. [59] reported the production of ascorbic acid by a... 

Two types of reactors were utilized 1) a conventional (co-feed) fixed bed reactor and 2) a tubular membrane reactor. Both reactors were filled with the catalyst particles. A schematic illustration of the configurations used is shown in Fig. 12.15. 

Gallucci F., Paturzo L., Basile A. A simulation study of the steam reforming of methane in a dense tubular membrane reactor. Int.J. Hydrogen Energy 2004 29 611-617. 

Enick, R.M. Hill, J. Cugini, A.V., Rothenberger, K.S. Mcllvried, H.G. A Model of a High Temperature, High Pressure Water-Gas Shift Tubular Membrane Reactor , Am. Chem. Soc., Fuel Chem. Div., Prepr. Pap., 44(4), (1999) 919-923. 

Figure 6. Tubular membrane reactor (fixed-bed catalyst + inert porous membrane) for dehydrogenation reactions [51].

To illustrate this approach, we will consider a new example the case of a simple tubular membrane reactor for which we wish to show the dependence between the conversion (rij of the main reactant and other variables which influence the process. 

Figure 6.5 Principle of the simple tubular membrane reactor.

Single tubular membrane reactors are often used in experimental and feasibility studies. Its justification for use in production environments can sometimes be made in small volume applications. As mentioned in Chapters 4 and 5, inorganic composite membranes consist of multiple layers. The inner most layer in a tubular composite membrane reactor does not necessarily possess the finest pores. For example, a two>layered tubular ceramic membrane reactor used for enzymatic reactions has an inner layer containing pores larger than those in the outer layer [Lillo, 1986]. The pores of the inner layer are immobilized with enzymes. Under the influence of an applied pressure difference across the membrane matrix, a solution entering the hollow central core of the tube Hows into the inner layer where the solution reacts with the enzyme. The product which is smaller than the enzyme passes through the permselective outer layer membrane which retains the enzyme. Thus the product is removed from the reaction mixture. 

Deactivation of the catalyst is always an industrially important problem. For fixed-bed reactors, to which class the cross-flow reactors also belong, catalyst poisoning is a particularly delicate matter, since the reactivation is often complicated and expensive. Some poisoning effects may be difficult to explain and understand, and this of course causes extra uncertainty. One example of such poisoning was the observation by Amor and Farris [33] that a special deactivation effect appeared in liquid-phase hydrogenation of toluene using a spiral tubular membrane reactor. Toluene was not hydrogenated at all over the palladium foil used. This phenomenon and reactivation of the catalyst have recently been studied by Ali et al. [56]. 

Enzyme immobilization via dynamic formation of an enzyme gel layer has been applied both to flat and tubular membrane reactors, either recirculating the permeate or the axial stream. 

Lu et al. [50] investigated the OCM in a tubular membrane reactor, which consisted of two layers, with SrFeCoo.sOs as the MIECM and BaCeo.6Smo.4O3 as the secondary layer deposited inside the SrFeCoo.sOs tube to minimize the effect of the total oxidation catalytic activity of SrFeCoo.sOs. La/MgO as OCM catalyst was added inside the reactor. C2 product yields of up to 7% were reported. 

A prototypic design for a tubular membrane reactor can be found in linde AG s patent appUcation shown in Fig. 8.9 [24]. This design uses a bundle of ceramic membrane tubes that are inside a pressure vessel. The tubes are closed at one end with the air fed to the tubes in the annulus between the ceramic tube, labeled 32,... 

FIGURE 6.25 Scheme of the multi-tubular membrane reactor. (Taken from Figure 1 of M.E. Adrover, A. Anzola, S. Schbib, M. Pedernera, D. Borio, Catal. Today 156 (2010) 223.)... 

Dixon, A.G., 2001. Analysis of Intermediate Product Yield in Distributed-Feed Nonisothermal Tubular Membrane Reactors. Catalysis Today, 67(1-3) ... 

Gallucci F, Tosti S, Basile A (2008) Pd-Ag tubular membrane reactors for methane dry reforming a reactive method for CO2 consumption and H2 production. J Memb Sci 317 96-105... 

Wang H, Cong Y, Zhu X and Yang W (2003b), Oxidative dehydrogenation of propane in a dense tubular membrane reactor . React Kinet Cat Lett, 79(2), 351-356. 

Wang H, Cong Y and Yang W (2005), Oxidative coupling of methane in Bao.5Sro.5Coo.gFeo.203.5 tubular membrane reactors , Catal Today, 104,160-167. 

Diels, L., van Roy, S., Somers, K., Willems, I., Doyen, W, Mergeay, M., Springael, D. and Leysen, R. 1995. The use of bacteria immobilized in tubular membrane reactors for heavy metal recovery and degradation of chlorinated aromatics. Journal of Membrane Science, 100,249-258. 

Figure 8.1 Conceptual scheme of a tubular membrane reactor (MR).

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