Thermally driven processes

Membranes can contribute significantly to new concepts in more energy-efficient and low C02 emission power generation, and the following section explores some of these cases as alternatives to conventional amine-absorption-based thermally driven processes. 

Separation processes are intensively used in practically all industrial processes. About 40-50% of the energy use in major commodity-producing industries is utilized in separations, but most of these are still carried out by traditional thermally driven processes [1],... 

The drawbacks of the mesa structure stated above are acknowledged in US-A-S189297. Instead, a structure having a planar surface is proposed. Isolation junctions are formed by a thermally driven process converting regions in a top layer to an opposite type of material. A method to fabricate the structure without removing it from an epitaxial reactor is also disclosed. 

Vaccum membrane distillation, such as any membrane distillation process, is a thermally driven process in which a feed solution is bought into contact with one side of a microporous membrane and a vacuum is created on the opposite side to create a driving force for transmembrane flux (Figure 19.8). The microporous membrane only acts as a support for a vapor-liquid interface, and does not affect the selectivity associated with the vapor-liquid equilibrium [76]. 

As a thermally driven process, the photoacid diffusion length and rate in CARs is temperature dependent, as illustrated in Fig. 17.24 for the diffusion of perfluoro-octane sulfonate photoacid in partially protected poly(4-t-butyloxycarbonyloxy-strene)-based resist. Within normal processing conditions, the higher the PEB temperature, the faster is the rate of the photoacid diffusion and the longer is the diffusion length. Although the PEB temperature can be used to modulate photoacid diffusion and consequently resist sensitivity, it nevertheless involves a trade-off... 

Being MD, a thermally driven process solar energy can be directly applied. Combinations of MD with other renewable sources have not been implemented until now. However, an interesting application of MD using solar and wind energy for water supply was patented by Wenten et al. (2002). This development was designed for small board and rural or coastal areas where electricity is not available. The feed is preheated by permeate stream... 

First we will illustrate the minimum energy required to separate a small amount of mixture for the following processes evaporation of water from a saline solution recovery of water by reverse osmosis separation of an ideal binary gas mixture by membrane permeation. Then we will consider the definition of net work consumption for thermally driven processes. Next we will consider a variety of separation processes vis-k-vis their minimum energy requirement for separation. 

In Chapter 1, R.C. De Mattel and R.S. Feigelson review electrochemical methods for the deposition and doping of semiconductors. Potential advantages of these methods over thermally driven processes include electrical control over the deposition rate, relatively low deposition temperatures, and applicability to a wide range of materials. Despite these advantages, electrochemical methods have been overlooked as a route to electronic semiconductors. The incentive for research described in this chapter has come largely from photovoltaic applications. 

From one perspective, the second law of thermodynamics addresses directionality. From another, it is about the reversibility and irreversibility of processes. In this section, we review examples of when mechanically and thermally driven processes are reversible and when they are irreversible. 

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