GB1112580A - Volume compensation in vapour sorption systems - Google Patents

Abstract

1,112,580. Seperating gases. CONTINENTAL OIL CO. 8 Oct., 1965, No. 42798/65. Heading B1L. In a closed-circuit heated gas regeneration system for adsorption apparatus, in which the regenerated bed is recooled before use, there is incorporated in the regeneration circuit a "compensator" whose heat capacity and volume are substantially equal to those of the bed, which has been previously heated while another bed was being cooled, so that as the bed being regenerated is heated, the "compensator" is cooled and the volume of gas in the regeneration circuit is held substantially constant. Compensators are thus essentially regenerative heat exchangers whose void volumes are made equal to those of the adsorption bed. In Fig. 1 is shown an apparatus for the separation of vapours from natural gas. Gas from line 1 enters adsorber 4, 5, or 6 by line 2, 2A, or 2B respectively and leaves by lines 7, 7A, or 7B respectively and line 3. Regeneration gas from heater 23 and line 8 passes to the adsorbers via lines 9, 9A, or 9B respectively and leaves via lines 10, 10A, and 10B respectively and line 11 from which it passes to coolers 14 and 15 and liquid separator 16, from which liquids are removed by line 17. Regenerating gas now passes by line 18, and lines 19 and 19A respectively to compensator 20 or 21, from which it leaves by lines 33 and 31 respectively to line 22 and heater 23. Cooling gas leaves the compensators by lines 35 or 32, line 34, pump 47 line 24 and line 26, 26A, or 26B. It is returned to the compensators by lines 27, 27A, or 27B, 28, and 30 or 30A. With such a system at the end of the desorption phase, the adsorber so treated is hot while the corresponding compensator is cool, and the after cooling an adsorber the corresponding compensator is hot. At the changeover between each phase of the cycle there is a displacement phase in which gas in the absorber being regenerated and the corresponding compensator is displaced into the adsorber which is about to be regenerated and the other compensator, while gas in the cooling circuit is displaced into the new cooling circuit, so that loss of vapour from the system is minimized. During the displacement phase the coolers may be bypassed by conduit 36. Specified adsorbents are active carbon and silica gel. The compensators may be filled with a porous or permeable non-adsorbent which is stable under operating conditions, e.g. up to 700‹F, specified materials including metal turnings and "shapes", glass fibres, glass spheres, crushed glass, crushed or brown slag, quartz, volcanic rocks and ceramics. During regeneration vapours of light hydrocarbons are first displaced from the adsorbent, and so the volume of gas in the regeneration circuit first increases and then decreases. This may be compensated for by arranging that the void volume of the compensator decreases in the direction of flow of the regeneration gas, or by providing some other pressure equalizer. The flow of regeneration gas in the compensator may be cocurrent or countercurrent to that of the cooling gas.