Metallic membrane reactors

Edlund, D.J. and W. Pledger, Thermolysis of hydrogen sulfide in a metal membrane reactor, /. Membr. Sci., 77, 255-264, 1993. 

Gas solubility (and thus permeation rate) in dense metal membranes typically decreases with increasing temperatures. Therefore, dense metal membrane reactors have the inherent advantage of avoiding runaway reactions. 

Edlund, DJ., W.A. Pledger. B.M. Johnson and D.T. Fricscn, 1992. Toward economical and energy-efficient production of hydrogen from coal using metal-membrane reactors (paper 11. present at 5th NAMS Annual Meeting. Lexington. Kentucky. USA. 

Based on matenal considerations, membrane reactors can be classified into (1) organic-membrane reactors, and (2) inorgamc-membrane reactors, with the latter class subdivided into dense (metals) membrane reactors and porous-membrane reactors Based on membrane type and mode of operation, Tsotsis et al. [15] classified membrane reactors as shown in Table 3. A CMR is a reactor whose permselective membrane is the catalytic type or has a catalyst deposited in or on it. A CNMR contains a catalytic membrane that reactants penetrate from both sides. PBMR and FBMR contain a permselective membrane that is not catalytic the catalyst is present in the form of a packed or a fluidized bed PBCMR and FBCMR differ from the foregoing reactors in that membranes are catalytic. 

Tosti S, Borelli R, Borgognoni F, Favuzza P, Rizzello C, Tarquini P (2008) Study of a dense metal membrane reactor for hydrogen separation from hydroiodic acid decomposition, hit J Hydrogen Energy 33 5106-5114... 

A multilayer metallic membrane reactor for H2S decomposition was patented by Edlund and Friesen [78] and, later, further described by Edlund and Pledger [79, 80]. The membrane consisted of three distinct layers a base-metal/mechanical support layer, an intermediate layer and a coating-metal layer. The coating metal was a H2-permeable metal resistant to chemical corrosion by H2S (e.g. Pd alloyed with about 40% Cu). It was reported that at 700°C, the membrane-assisted... 

A large number of hydrogenation and dehydrogenation reactions were tested in the early studies of dense-metal membrane reactors (see listing in Shu et al. [34], Hsieh [35], and Gryaznov and Orekhova [36]). Many works tested the dehydrogenation of cyclohexane to benzene as a model reaction since it can be carried out at low temperature with no side reactions and no deactivation a conversion of 99.5% was achieved with a palladium membrane, compared with 18.7% at equilibrium, at 200°C [31]. 

Lopez, E., Divins, N.J. and Llorca, J. (2012) Hydrogen production from ethanol over Pd-Rh/Ce02 with a metallic membrane reactor. Catalysis Today, 193, 145-150. Montane, D., Bolshak, E. and Abello, S. (2011) Thermodynamic analysis of fuel processors based on catalytic-wall reactors and membrane systems for ethanol steam reforming. Chemical Engineering Journal, 175, 519-533. 

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