Hydrogen separation integrated membrane

In 1980, Permea, with its hydrogen-separating Prism membrane, launched the first large industrial application of GS membranes. Since then, membrane-based operations, substituting or to be integrated with the traditional ones, have had a rapid growth, with many companies, such as Cynara-NATCO, UOP Separex, GMS, Generon, Praxair, Air Products, and Ube, involved in this field. ... 

As most of the chemical reactions for hydrogen production are equilibrium-limited reactions, the integration of hydrogen separation through membranes in the reactor leads to equilibrium shift toward the products. Therefore, in membrane reactors higher conversions can be achieved compared with conventional reactors operated under the same conditions (pressures and temperatures) [1]. 

An integrated proof-of-concept (POC) size fluidized-bed methane reformer with embedded palladium membrane modules for simultaneous hydrogen separation is being developed for demonstration (Tamhankar et al., 2007). The membrane modules will use two 6 in. X 11 in. Pd-alloy membrane foils, 25-pm thick, supported on a porous support. The developmental fluidized-bed reactor will house a total of five (5) membrane modules with a total membrane area of about 0.43 m2 and is scheduled for demonstration by September 2007. 

Franz et al. [93] developed a palladium membrane micro reactor for hydrogen separation based on MEMS technology, which incorporated integrated devices for heating and temperature measurement. The reactor consisted of two channels separated by the membrane, which was composed of three layers. Two of them, which were made of silicon nitride introduced by low-pressure chemical vapor deposition (0.3 pm thick) and silicon oxide by temperature treatment (0.2 pm thick), served as perforated supports for the palladium membrane. Both layers were deposited on a silicon wafer and subsequently removed from one side completely... 

Fig. 9.2 Scenario for integrating hydrogen separation membranes with coal gasifiers and WGS reactors for producing hydrogen at high purity while retaining CO2 at high pressure and concentration for economic sequestration...

High-temperature membranes allow hydrogen separation to accompany and be thermally integrated with chemical reactions. First and foremost - and always central in equilibria with oxidic membranes - is the equilibrium between hydrogen, oxygen, and water vapor Eq. (1.1) ... 

The hydrogen produced at the reaction device exit is recovered in a separation unit downstream (Fig. 9.15). In the study performed, the two reactors plus the separator were compared in terms of capital and operating costs, with a Pd-based membrane reactor in which the pure hydrogen is recovered at the permeate side (Fig. 9.16). Table 9.8 shows the main operating conditions of the industrial plant considered. The membrane reactor unit was designed in order to operate with industrial quantities and to achieve the same industrial hydrogen recovery. An integrated membrane system in which the feed stream is first fed to a Pd-based... 

Few studies are reported in literature dealing with the integration of an autothermal reforming reactor with a membrane for hydrogen separation, and most of them are simulation studies. 

The research project allowed to compare two different ways of integrating catalytic reaction and hydrogen separation one in which the membranes are set inside the reaction environment (e.g. the membranes constitute the catalytic tube walls) and another one in which the catalytic module is separated from the hydrogen permeation one. 

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