Membrane reactors integrated

FIGURE 13.17 Schematic flow diagram of the integrated membrane reactor system. (From Gan, Q., Allen, S.J., and Taylor, G., Biochem. Eng. J., 12, 223, 2002. With permission.)... 

Gan Q, Allen SJ, and Taylor G. Design and operation of an integrated membrane reactor for enzymatic cellulose hydrolysis. Biochem Eng J, 2002 12(3) 223-229. 

Figure 5.15 Schematic flow diagram of the integrated membrane reactor system. From Ref. [341] with permission.

Figure 1.4. A conventional membrane reactor system (a) and an integrated membrane reactor system (b).

A technical way to fulfill this plan is to surround the reacting mixture by a membrane selectively permeable to one of the products at least (Integrated Membrane Reactor). As a result, the reaction rate of the reverse reaction is lower than that of the forward reaction and the conversion increases theoretically to the value corresponding to the complete depletion of the limiting reactant... 

An integrated membrane reactor (IMR) is usually composed by a tube, packed with catalyst pellets, inside which one or more membrane modules are assembled (Fig. 4.7). The catalyst could be also packed in the inner tube, but generally it is preferred assembling the membrane in such a way that the higher pressure (reaction pressure) is imposed outside membrane wall. 

Integrated membrane reactor configmation. Selective membrane is assembled directly inside the reaction environment, so that the hydrogen produced by reactions is immediately removed. 

Natural gas steam reforming Integrated membrane reactor 20-50% Chap. 5... 

Autothermal reforming Integrated membrane reactor 5-20% Chap. 6... 

Water-gas shift Integrated membrane reactor 10% Chap. 7... 

Alkanes dehydrogenation Integrated membrane reactor 50-300% Chap. 9... 

Integrating the selective membrane in a critical enviromnent as chemical reaction one (high temperature and pressure, presence of membrane contaminants), i.e., imposing the integrated membrane reactor configuration, is a challenging issue. Nowadays, only laboratory scale prototypes have been constructed, and even if promising performance has been obtained, the reactor scale-up problems have stiU not be properly faced. 

The major features and applieadon opportunities for integrated membrane reactor and staged membrane reactor configuration have been described in some details. We may conclude that membrane reactors actually show promises for conversion of equilibrium-limited reactions, selectivity toward some intermediates and improvement of energy efficiency. Consistent application of such technology... 

At the same operating conditions, IMR leads to better performance, since an integrated membrane reactor is equivalent to an infinite series of reactor + separator modules... 

Two membrane reactor configurations, the staged membrane reactor (SMR) and the integrated membrane reactor (IMR), are presented and compared, with the following main outcomes ... 

Integrated membrane reactor (IMR), where the selective membrane is integrated directly in the reaction environment and the reaction product is removed as it is produced. A sweeping gas is fed counter-currently (as shown in Fig. 12.1) or co-currently to carry out the product permeated through the membrane. 

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