Current Hurdles

It is evident that zeoHte membranes can have added value in catalysis, but industrial applications are stiU lacking. Thus, the question remains what the major factors are that stand in the way of application. The following factors are considered troublesome and are discussed in more detail  

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In this chapter, the focus is on how zeohte membranes can be appHed in the field of catalysis and to what extent this is successful. The latter is illustrated by reviewing some commonly studied zeohte membrane applications. Finally, the current hurdles that impede industrial application are discussed and some remarks... 

There is a clear need for the synthesis and more complete characterization of new PEM polymeric materials. Polymers bearing functional moieties for proton conduction might also be designed to serve as a host for inorganic compounds to afford a proton conducting component in a blend, as well as a standalone PEM. The two current hurdles for polymeric membranes are the high protonic conductivity at low water contents (e.g. under conditions of 120 °C and... 

G Saraco, G F Versteeg, W P M van Swaaij, Current hurdles to the success of high-temperature membrane reactors , J Membr Sci, 1994, 95, 105-123... 

Tennison S. Current hurdles in the commercial development of inorganic membrane reactors. Membr. Technol. 2000 128 4-9. 

G. Saracco, G.F. Versteeg and W.P.M. van Swaaij, Current Hurdles to the Success of High-Temperature Membrane Reactors.. Membr. Sci., 95 (1994) 105. 

Project screening means checking that the predicted economic performance of a project passes a prescribed threshold or hurdle . Investors commonly apply a screening value to the project, which is a chosen IRR at a chosen oil price (for example, 20% IRR at 20/bbl). Provided the project IRR exceeds the hurdle rate the project is considered further, otherwise it is rejected in current form. 

The economic)technical approach focuses on the question of which occurrences can be extracted economically with today s technology. According to this approach, all occurrences that at present are economically extractable with existing available technology are classified as conventional, whereas occurrences that are not extract-able at present owing to economic or technical hurdles are considered unconventional. The physical properties of the oil are not taken into account. It is important to note that, in this approach, the boundary between conventional and unconventional crude oil is current, as it is subject to the market price of oil, the production cost and the available technology. 

It is clear that the combination of different architectures and the precise localization of functionalities within a single macromolecule provide unique opportunities for the control of molecular shape as well as molecular, optical, and electronic properties. A significant hurdle that still remains today is the relatively demanding multistep process used to prepare dendrons and hybrids. This, in turn, translates into limited availability but, as high added-value applications emerge, it is clear that current, as well as yet-to-be-developed, syntheses will be used to prepare specialty materials that benefit from the unique properties derived from the combination of dendritic and linear architectures. 

Issues with mass transport resistance, especially at higher current densities, represent an important hurdle that fuel cells need to overcome to achieve the required efficiencies and power densifies that different applications require. Diffusion layers represenf one of fhe major fuel cell components that have a direct impact on these mass transport issues thus, optimization of the DLs is required through the use of differenf experimental and characterization techniques. 

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