Membrane reactor hydrogenation

Below, we first briefly describe conventional hydrogen production. Then the combination of hydrogen production and CCS is described. Finally, we elaborate on two of the technologies for more efficient hydrogen production with C02 capture that are currently in the R D phase hydrogen membrane reactors and C02 sorption enhanced reactors. 

J.W. Dijkstra, Y.C. van Delft, D. Jansen, P.P.A.C. Pex, Development of a hydrogen membrane reactor for power production with pre-combustion decarbonisation, Proceedings of the 8th International... 

The hydrogen membrane reactor was initially evaluated by measuring the performance of a pure palladium membrane. The permeability of pure palladium under various conditions has been well established and therefore can be used as a baseline test to verify if a new hydrogen membrane reactor is calibrated properly. At 440°C and under a simulated WGS feed stream, the pure palladium membrane exhibited a permeability of 2.0 x 10 mol m s Pa that is consistent with literature reports. 

Catalytic Dehydrogenation of Ethane in Hydrogen Membrane Reactor... 

Jansen D, Dijkstra JW, van den Brink RW, Peters TA, Stange M, Bredesen R, Goldbach A, Xu HY, Gottschalk A, Doukelis A (2009) Hydrogen membrane reactors for CO2 capture. Energy Procedia 1 253-260... 

Figure 7.10 Exploded isometric view of the different layers of the hydrogen membrane reactor, fSource After Ref [148])...

Michelsen, F. A., WiUielmsen, 0., Zhao, L., Asen, K. I. (2013). A distributed dymamic model of a monohth hydrogen membrane reactor. Energy Conversion and Management, 67, 160—170. 

Dijkstra J. W., van Delft Y. C., Jansen D. and Pex R, Development of hydrogen membrane reactor for power production with pre-combustion decarbonisation, Proc. of GHGT 5, Trondheim (NO), June 18-23,2006. 

Dijkstra J. W, Jansen D., Van den Brink R.W. and Reters T. A., Development of Hydrogen Membrane Reactors for CO2 Capture, in Eide L. I. (Ed.), Carbon Dioxide Capture for Storage in Deep Geological Formations - Results from the CO2 Capture project, CRL Press, 3 (2009) 121-134. 

As an example the use of ceramic membranes for ethane dehydrogenation has been discussed (91). The constmction of a commercial reactor, however, is difficult, and a sweep gas is requited to shift the product composition away from equiUbrium values. The achievable conversion also depends on the permeabihty of the membrane. Figure 7 shows the equiUbrium conversion and the conversion that can be obtained from a membrane reactor by selectively removing 80% of the hydrogen produced. Another way to use membranes is only for separation and not for reaction. In this method, a conventional, multiple, fixed-bed catalytic reactor is used for the dehydrogenation. After each bed, the hydrogen is partially separated using membranes to shift the equihbrium. Since separation is independent of reaction, reaction temperature can be optimized for superior performance. Both concepts have been proven in bench-scale units, but are yet to be demonstrated in commercial reactors. 

Fig. 7. Equihbrium conversion of ethane versus temperature at 210 kPa in a membrane reactor. The effect of hydrogen removal on ethane conversion is...

One of the most studied applications of Catalytic Membrane Reactors (CMRs) is the dehydrogenation of alkanes. For this reaction, in conventional reactors and under classical conditions, the conversion is controlled by thermodynamics and high temperatures are required leading to a rapid catalyst deactivation and expensive operative costs In a CMR, the selective removal of hydrogen from the reaction zone through a permselective membrane will favour the conversion and then allow higher olefin yields when compared to conventional (nonmembrane) reactors [1-3]... 

A special version of the membrane reactor using Pd was made for separating hydrogen and oxygen and their controlled reaction. 

The design of the Pd-membrane reactor was based on the chip design of reactor [R 10]. The membrane is a composite of three layers, silicon nitride, silicon oxide and palladium. The first two layers are perforated and function as structural support for the latter. They serve also for electrical insulation of the Pd film from the integrated temperature-sensing and heater element. The latter is needed to set the temperature as one parameter that determines the hydrogen flow. 

GP 11] ]R 20] Investigations with a Pd membrane reactor relied on reaction of streams separated via a membrane (to prevent complete mixing of reactants, not to enhance conversion) [11]. A hydrogen/nitrogen stream is guided parallel to an oxygen stream, both separated by the membrane and water is thereby formed. The membranes, made by thin-film processes, can sustain a pressure up to 5 bar. 

Barbiery, G. et al., Hydrogen production using membrane reactor, Korean Membrane., 5,68,2003. 

Ishihara, T. et al., Decomposition of methane over Ni/Si02 catalysts with membrane reactor for the production of hydrogen, Chem. Lett., 93, 1995. 

Because Pd-alloy membranes operate at high temperatures in the range of WGS reaction and on the lower end of methane reforming reaction, they can be used in a membrane reactor configuration for the simultaneous separation of hydrogen. As discussed earlier,... 

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