Oxygen separation system

The separation of oxygen from air is extremely important in connection with medical treatments, combustion processes, etc. Relatively thin effective membrane layers are required for practical oxygen separation systems, because the permeability coefficients of oxygen of most polymers are lower than those of hydrogen and carbon dioxide. 

In the SOFC systems, fuel and air enter the SOFC stack, and electricity, exhaust gas and possibly hot water or steam exit the system. Such systems Include atmospheric SOFC CHP systems pressurised SOFC/turbine hybrid systems atmospheric SOFC residential and auxiliary power systems and oxygen separating systems. The difference between an SOFC stack and an SOFC system is generally referred to as the balance-of-plant (BOP). BOP equipment may differ for each application, depending on the size of the system, the operating pressure, and the fuel used. 

A typical SOFC system takes fuel and air as the input and electricity hot water or steam is the main output. Major commercial organisations have shown interest and made large investments in this technology. They have come up with their own designs for different applications. Different SOFC systems include residential and auxiliary power systems, oxygen separating systems, pressurised SOFC or turbine hybrid systems, and atmospheric SOFC combined heat and power (CHP) systems. 

Both air and oxygen processes can be designed to be comparable in the following areas product quaUty, process flexibiUty for operation at reduced rates, and on-stream rehabiUty (97,182). For both processes, an on-stream value of 8000 h/yr is typical (196). The rehabiUty of the oxygen-based system is closely linked to the rehabiUty of the air-separation plant, and in the air process, operation of the multistage air compressor and power recovery from the vent gas is cmcial (97). 

A conventional pump-and-treat extraction system is typically designed to recover only ground-water. Integrated or separate systems have also been used to capture free product or contaminated vapor concurrently with groundwater. More detailed information relevant to the application of pump-and-treat at sites contaminated with MTBE and other oxygenates and in general is available in the literature.88-90... 

Fig. 5. Exploded view of an ion-exchange membrane electrochemical oxygen separator. Oxygen removal characteristics of the flow-through type oxygen removal system are shown. Air cathode area = 100 cm2, water temperature = 40 °C.

Ibsen, K., Equipment design and cost estimation for small modular biomass systems, synthesis gas cleanup, and oxygen separation equipment, Contract Report NREL/SR-510-39943, NREL Technical Monitor, Section 2, May 2006. 

Figure 15. The mean trajectories of amylosic chains based on the rigid residue (filled circles) and relaxed residue (open circles) models projected into the XY plane of a coordinate system attached to a terminal residue. Circles represent the mean positions of successive glycosidic oxygens in the primary sequence. The persistence vector (mean end-to-end vector) for a chain of x residues is the vector (not shown) connecting the origin and the mean position of the glycosidic oxygen separated from it along the chain by x virtud bonds.

Many carboxylic acids exist in the free state as hydrogen-bonded dimers with an oxygen-oxygen separation (between oxygens linked to the same carbon atom) close to 220 pm. Replacement of these hydrogens by two metal atoms results in the close approach of the two metal atoms.28 Much of the interest in these dinuclear paddlewheel systems has been generated by a need to understand the nature of these metal-metal interactions. The natural desire of chemists is to use formal bond orders as an index of this interaction and much has been published to this end. However, there are growing indications that such a formal concept is not entirely appropriate for such systems.29... 

Photocatalytic Hydrogen and Oxygen Evolution in Separate Systems... 

Body fluids, such as serum, contain several different carotenoids in low amounts. The crucial point in the isolation and analysis of these samples is the enrichment factor. Serum samples can be directly analysed with hyphenated extraction-sample enrichment-separation systems, such as on-line SPE-HPLC employing tailored stationary phases [29]. By using special restricted access materials (RAMs) for sample enrichment, the carotenoids are retarded on the pre-column while the protein binding is broken and the macromolecules are eluted. The preparation of artifacts is hindered, as the whole analysis steps take place under conditions of light- and oxygen-exclusion. The scheme of on-line SPE-HPLC is presented in Figure 5.2.2. 

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