Single-stage operations

As it is desirable that the separative capacity of the stage be independent of the concentration of the material with which it is operating, the terms in the equation involving the concentration are set equal to a constant, taken for convenience to be unity, and the separative capacity of a single stage operating with a cut of one-half is seen to be ... 

This is satisfactory for single-stage operation if temperature does not limit. 

Carbon Dioxide Removal. Aside from contained carbon dioxide which is removed from syngas when absorbing hydrogen sulfide, the total carbon dioxide produced in the methanation system is removed by conventional absorption in a single-stage operation in which the volume of gas to be treated is minimum and the partial pressure of the carbon dioxide is maximum. 

The experimental results are summarized in Table 2. CO2 permeance (Rco2), selectivity (oicx)2/N2) and CO2 recovery (Y) increased with decreasing CO2 mole fraction in feed gas. CO2 in the feed gas was successfully concentrated to 97-99 % by the single-stage operation. CO2... 

All freeze separation processes depend on the formation of pure solvent crystals from solution, as described for eutectic systems in Section 15.2.1. which allows single-stage operation. Solid-solution systems, requiring multistage-operation, are not usually economic. Several types of freeze crystallisation processes may be designated according to the kind of refrigeration system used as follows . 

A thermodynamic analysis of the energy requirements of desalting processes is presented, to clarify the conditions under which such calculations are valid. The effects of departure from isothermal operation, finite product recovery, differential as opposed to single-stage operation, and salt concentration in the feed are examined. A comparison shows that there is essentially no difference between the energy requirements for a distillation and a freezing process. The minimum heat consumption and maximum number of efFects for a multiple-effect evaporation plant are calculated. The above analysis leads to the conclusion that efficiencies in the range 10 to 20% will be very difficult to achieve. 

Single-Stage Adsorption Contact filtration can be carried out as a single-stage operation (Figure 10.8) either in a batch or a continuous mode. If we assume that the amount of liquid retained with the solid is negligible, the material balance for a solute gives... 

This equation may be rearranged in terms of X. For the single-stage operation, set... 

Note The triple-quadrupole mass spectrometer can be configured for single-stage operation. 

Flash vaporization is a single-stage operation wherein a liquid mixture is partially vaporized, the vapor is allowed to come to equilibrium with the residual liquid, and the resulting vapor and liquid phases are separated and removed from the apparatus. It may be batch or continuous. 

Staged separations at controlled pressure ratios have been shown to produce more oxygen from a speciflc amount of air and at lower power consumption when compared with the single-stage operation [23]. However, staging in ITM devices is not necessary to improve product purity. 

Drying of granulated moist mix is performed in one or two stages to about 12%-13% (wb) moisture content. Airlift dryers are used in a single-stage operation. The dryer consists... 

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