Hydrogen separation palladium-based membranes

The unusual interaction of hydrogen with palladium-based membrane materials opens up the possibility of oxidative hydrogen pump for tritium recovery from breeder blankets. The feasibility for this potential commercial application hinges on the hot-fusion and cold-fusion technology under development [Saracco and Specchia, 1994]. At first, Yoshida et al. [1983] suggested membrane separation of this radioactive isotope of hydrogen followed by its oxidation to form water. Subsequently, Hsu and Bauxbaum [1986] and Drioli et al. [1990] successfully tested the concept of combining the separation and reaction steps into a membrane reactor operation. 

N. I. Timofeev, F. N. Berseneva, V. M. Makarov, New palladium-based membrane alloys for separation of gas mixtures to generate ultrapure hydrogen, Int.]. Hydrogen Energy 1994, 39(11), 895-898. 

The first scientific study on palladium-based membranes, available in the Elsevier Scopus database [1], where more than 6,000 scientific journals are taken into account, is dated 1955, when Juenker et al. [2] analyzed the use of palladium membranes for hydrogen purification. Today, it is well known that the palladium membranes are, mainly, applied in the field of gas separation and, particularly, in the issue of the hydrogen rich-stream purification [3], As reflected by the data of Fig. 2.1, the scientific interest towards palladium-based membranes is increased... 

Arstad et al. [141] used a self-supported, Pd/(23 wt%) Ag-based MR (with a thickness of 1.6 pm) achieving 100.0% the production of pure hydrogen. Hence, the authors concluded that the low-thickness of the paUadium-based membrane can represent a fundamental step for reducing the palladium-cost and making competitive the hydrogen separation technologies by palladium-based membrane. 

Membrane Reactor Technologies Ltd (MRT) has experimentally verified the permeative-stage membrane reactor concept. With the membranes outside the reaetor, operation at more favorable conditions for both reaction (750 °C) and membrane separation (450 °C or lower) is possible. A decrease in the metal cost of palladium-based membranes by 86.5% and membrane area by >70% to aehieve equal hydrogen production capacity was reported. The volume of reformer decreases accordingly, thus, the costs of both the reactor and membrane module are reduced. 

Tong H D (2004), Microfabricated palladium-based membranes for hydrogen separation , PhD thesis. Transducers Science and Technology of the MESA+ Research Institute at the University of Twente, Enschede, Netherlands. 

Another research field under development is based on MR technology. In particular, in recent years, palladium-based membrane technology has been widely studied both as a permeator and as in MRs. The latter allows combining hydrogen production and its separation in only one device with many benefits in terms of process intensification with respect to the conventional process. However, before addressing this topic, brief overviews on MSR kinetic and reforming catalyst are given. 

Palladium-based membranes for hydrogen separation have been deeply investigated in the latest decades. The possibility of separating a pure hydrogen stream makes them significant for applications requiring uncontaminated hydrogen, such as low temperature PEMFC (Roses et a/., 2011). 

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