Purge gas stripping

Displacement Desorption. The temperature and pressure are maintained essentially constant, as in purge gas stripping, but instead of an inert purge the adsorbed species are displaced by a stream containing a competitively adsorbed species, as in displacement chromatography. The method is applicable to both gas and liquid systems. 

Steam stripping, which is widely used in the regeneration of solvent recovery systems using an activated carbon adsorbent, can be considered as a combination of thermal swing and displacement desorption. Vacuum desorption, which is used in some versions of the Union Carbide IsoSiv process for separation of medium-chain linear paraffins as well as in some air separation systems can be considered as a special case of pressure swing. 

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Purge gas stripping. The bed is regenerated by purging with a non adsorbing inert gas... 

Displacement desorption. The method is essentially the same as for purge gas stripping but the regeneration stream is adsorbed and displaces the adsorbed species... 

FIGURE 11.6. Simulated adsorption and desorption curves for a two-bed cyclic isothermal purge gas stripping system showing progress towards the cyclic steady stale. Cycle numbers are indicated on the curves. Broken lines represent profiles at the end of the desorption cycle while solid lines represent profiles at the end of the adsorption cycle. (From Chao. 0... 

Inert-purge gas stripping cycle. In this cycle the adsorbate is removed by passing a nonadsorbing or inert gas through the bed. This lowers the partial pressure or concentration around the particles and desorption occurs. Regeneration cycle times are usually only a few minutes. 

Displacement-purge cycle. The pressure and temperature are kept essentially constant as in purge-gas stripping, but a gas or liquid is used that is adsorbed more... 

Purge gas stripping Essentially at constant T andP Only for weakly sorbed species, purge flow is high. Not normally used when desorbate needs to be recovered Relatively uncommon without thermal swing since purging alone is only suitable for weakly adsorbed species ... 

After flue gas pretreatment, SO2 absorbed into Na2S02 solution sohds and chloride purged, SO2 stripped, regenerating Na2S02, and SO2 processed to S. 

The methods that generally are used to remove volatile organic chemicals (VOCs) from biological samples for analysis are applicable to chlorobenzene. These include headspace analysis, purge-and-trap (gas stripping) collection from aqueous solutions or slurry samples, solvent extraction, and direct collection on resins. Headspace analysis offers speed, simplicity, and good reproducibility for a particular type of sample. However, partitioning of the analyte between the headspace and the sample matrix is dependent upon the nature of the matrix and must be determined separately for different kinds of matrices (Walters 1986). 

The tips of the test swabs were cut off and placed in labeled plastic vials. One ml of 1M HNO was added, the samples were agitated and allowed to leach for 15 min. A 10 yul aliquot was placed on the tantalum strip and the purge gas flow was started (At alone for Sb and Ar H2 for barium). The atomizer unit was automatically cycled through preset time for drying, ashing and atomization (at 2500°C). Absorbance values were recorded on the chart recorder and results were obtained by comparison with a standard curve prepared for each tantalum strip. 

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