Inert purge cycle

One version of UOP purge IsoSiv for to naphtha employs inert-purge cycle (64). UOP also developed a similar process, OlefinSiv, for the... 

Regenerative adsorption units can be operated by a thermal-swing cycle, pressure-swing cycle, displacement-purge cycle, or inert-purge cycle. Combinations of these are frequently employed. 

Inert-Purge Cycle. In this cycle, the adsorbate, Instead of being removed by temperature Increase, is removed by passing a non-adsorbing gas containing no adsorbate through the bed. 

Displacement-Purge Cycle This cycle, which is somewhat similar to the previous one, differs from it in that a gas or vapor which adsorbs about as strongly as the adsorbate is used to remove the adsorbate (see Figure 1) Removal is thus facilitated both by adsorbate partial-pressure reduction in the fluid around the particles and by competitive adsorption of the displacement medium. As with the inert-purge cycle, the maximum delta loading is the equilibrium loading ... 

Displacement-Purge and Inert-Purge Cycles By far the most widespread embodiment of these cycles Is the separation of normal and lso-parafflns In a variety of petroleum fractions. These fractions In general contain several carbon numbers and can Include molecules from about C5 to about C g All of these separations use 5A molecular sieve as the adsorbent Its 0.5 nm pore diameter Is such that normal paraffins can enter but lso-parafflns are excluded this constitutes the basis for separation. 

The simplest cycle is the so-called inert-purge cycle, shown in Figure 14.19. It is basically a two-step process of a few minutes or hours duration. First is adsorption (often with heat evolution). 

Inen-puige cycles, given the recently demonstrated success in drying of azeotropes,1 would seem to be poised for use in several new separations. Prime candidates include those systems now separated by azeotropic and extractive distillation, many of which contain water as one constituent. The use of inert-purge cycles for isomer and other close-boiler sepurations sheuld also grow for those systems whose components can be easily separated from the purge gas,... 

Recently, a quite different use for an inert-purge cycle has emerged the removal of large amounts (up to and exceeding 20 wt. %) of water from organic streams. Thus, inert-purge adsorption can now compete directly with azeotropic and extractive distillation and other means for a number of azeotrope-breaking separations, the most common of which is the production of dry ethanol. The process, as depicted in Fig. 

---