Hydrogen membrane integration

A sweeping gas is fed through the inner tube, co-currently or counter-currently, in order to carry out the permeated hydrogen. Membrane integration can of course also be achieved by assembling many smaller... 

S. Elnashaie, T. Moustafa, T. Alsoudani, S.S. Elshishini, Modeling and basic characteristics of novel integrated dehydrogenation-hydrogenation membrane catalytic reactors, Computers Chemical Engineering, 24(2-7) 2000, 1293-1300... 

Localization of double bonds in unknown compounds has frequently been determined by ozonolysis. Unsaturated fatty acids of biological membranes are susceptible to ozone attack, but there are some important differences from autoxidation reactions. These include the fact that malonaldehyde is produced from linoleate by ozonolysis (53) but not autoxidation and also that ozonolysis does not cause double bond conjugation as judged by absorption at 233 nm (52). Reactions with the polyunsaturated fatty acids produce several possibilities for toxic reactions direct disruption of membrane integrity and toxic reactions caused by fatty acid hydroperoxides, hydrogen peroxide, and malonaldehyde. 

In relation to the hydrogen membrane processes, the direction of mass transfer would be defined from the retentate (hydrogen rich feed stream) to the permeate (hydrogen poor stream). Assuming a steady state permeation process and integrating Eq. 10.2 yields the governing, steady state form of Pick s law for membrane processes, Eq. 10.3,... 

In conclusion, hydrogen membranes can have significant impact on the overall process efficiency of gasification by implementation as a separation device or an integrated WGSMR. However, chemical degradation from syngas constituents... 

Natural gas steam reforming process is an ideal candidate for hydrogen selective membrane integration tanks to its high reaction endothermicity and the fast kinetics leading to equilibrium condition inside traditional reactors. 

Globally, if the GHSV value corresponding to the maximum pure hydrogen recovery is taken as optimal, the benefits of MR compared to TR are not enough to justify membrane integration (methane conversion improvement of 14.3%). Therefore, the optimal value can be taken equal to 6,000-6,500 h ... 

Membrane integration into the reaction environment ensures a first substantial hydrogen separation step (up to 90% of the hydrogen produced can be removed) as for CO2 separation, because of the higher carbon dioxide partial pressure in the reformer outlet stream, due to the hydrogen removal, physical separation methods could be used to separate CO2 rather than the chemical adsorption in mono-diethanol ammine (MDEA). 

Key words hydrogen production, power generation, COj capture, membrane integration, oxygen membranes for oxy-combustion, hydrogen separation membrane reactors. 

Layout of a power plant integrated with a hydrogen membrane reformer. (GT refers to gas turbine.)... 

A number of different plant layouts integrating hydrogen membrane reformers have been proposed in the literature. The main characteristics of these plants are reported in Table 10.2. Due to the wide variety of proposed layouts and design assumptions, it is difficult to obtain a clear indication of their relative thermodynamic performance. Efficiencies between 43% and 53% are reported, corresponding to penalties of 5-10% points with respect to the reference technologies without CO2 capture note that the extent of CO2 capture is -100% in cases where high selectivity dense membranes are used and no natural gas external firing is adopted. 

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