Air separation processes

X 10 m (l.9x lO " /t ) of heHum in each cubic meter (35 ft ) of air entering the air separation process, the small quantities of cmde coUected in even a large air separation unit may be easily appreciated. It is sometimes desirable, therefore, to combine cmdes coUected from several air plants and to process them at a centralized location in specialized equipment. 

VAROX An air separation process, allowing for variable oxygen demand. Developed by Linde from 1984. 

Figure 8. Capital Cost-Efficiency Relations Air Separation Process (5).

The cryogenic air separation process starts with air entering the plant through air filters, where it is compressed and cooled. The air is passed through heat exchangers for further cooling and for removal of water vapor and carbon dioxide by freezing. Solid adsorbents, such as molecular sieves, silicas, and aluminas can also be used to remove the water and carbon dioxide by adsorption before separation of... 

Carbon molecular sieve (CMS) is useful in air separation processes because of its ability to selectively discriminate on the basis of molecular size and hence adsorb the smaller oxygen molecule over nitrogen. The difference in the adsorption kinetics of various gases allows the separation of gas mixtures into pure components using pressure swing adsorption (PSA). 

Air leakage, vacuum systems, 164, 165 other gases, 165 Air properties, 674 Air separation process, 37 Air-water interaction, 231-234... 

In an air separation process using a perfect-mixing membrane separator, the feed air flow rate is rip = 1 x 10 cm- (STP)/s, with mole fraction oxygen yp = 0.21 and mole fraction nitrogen yp2 = 0.79. The membrane permeances for oxygen and nitrogen are, respectively, 1.5 x 10" and... 

Process design the report gives several examples of products that reduce environmental impact. It also identifies that electricity is the principal component of the air separation process, and that we constantly strive to improve the energy efficiency of our plants . Even so a no score has been awarded since only one example of a process improvement is given (changing a cleaning system to reduce ozone emissions), while at the same time the report includes a number of examples where tail-end treatment has been used to reduce emissions. 

Finally, it should he mentioned that the article hy Benedict and Gyftopoulos (j) in this volume illustrates the use of entropy balances for (i) analyzing the consumptions in an air-separation process, and (ii) for Second-Law costing analyses applied to optimal economic selection of the process equipment. 

Cryogenic air separation processes combine the principles of refrigeration and distillation in a single process to carry out the separation of oxygen, nitrogen and sometimes argon and other rare gases present in atmospheric air. 

The simplest air separation process is the Linde single column plant, first used in 1902. Figure 8 shows a simplified schematic of the process. 

A schematic representation of the air separation process using ITM as a whole is presented in Fig. 2.1. The driving force for the transport of oxygen is a difference in partial oxygen pressure (PO2) between the feed and permeate side of the membrane. As a result, oxygen permeates from the side with the high PO2 to the side with the... 

Fig. 6.2. Medium pressure air separation process, (a) Compressor, (ft) (1-3) heat exchanger, (c) 1. dryer, 2. low pressure column...

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