GB1445978A - Vortex nucleation scrubbing - Google Patents

Abstract

1445978 Centrifugal separators CARRIBBEAN PROPERTIES Ltd 26 Sept 1973 [2 Oct 1972] 45266/72 Heading B2P A process for the separation of particles from a gaseous phase in which the particles are suspended comprises (a) continuously supersaturating the gaseous phase with the vapour of a liquid which is capable of wetting the particles until at least some of the particles have been wetted by the vapour condensing on them, and (b) continuously spinning the supersaturated gaseous phase to centrifugally separate the wet particles therefrom. The supersaturation may be accomplished either (1) by saturating the gaseous phase at a relatively elevated temperature, e.g. by evaporation of the liquid or introduction of the vapour, and adiabatically cooling the saturated gaseous phase until condensation occurs; or (2) introducing the vapour at a relatively elevated temperature into a relatively cooler gaseous phase. One simple form of apparatus, not shown, for carrying out the process comprises a generally vertical conduit, having an inlet for the particle-bearing gaseous phase, preferably directed circumferentially around its vertical axis, near its lower end, one or more similarly circumferentially directed inlets for vapour or evaporatable liquid preferably situated above the gaseous phase inlet, an outlet for the scrubbed gaseous phase at the top, and an outlet for the condensed vapour carrying the scrubbed particles at the bottom. Another form of apparatus, Fig. I, comprises two coaxial hollow members 1, 11 defining between them an annular venturi conduit having a convergent portion 13. a throat 14 and a divergent portion 15. The member 1 is enclosed by insulation 18. An inlet 5 for gaseous feed, e.g. dust-bearing air, is tangential to the wall 2 of the member 1. Scrubbing fluid, e.g. saturated steam, is supplied through a valved conduit 10 and nozzles 8 tangentially directed to the wall 2. A mist collector 17 comprising a cylindrical mesh of knitted filaments is supported by a plate 16 having holes 20 for the passage of scrubbing liquid and centrifugally separated wet solid particles into the hollow conical bottom 4 of the member 1 from which they are continuously withdrawn via a valved outlet 6. An exhaust fan 21 may be installed within the member 11 to spin the gaseous phase as it is discharged to provide final scrubbing thereof. A further form of the apparatus, Fig. 2, comprises a conduit 1 made of a series of one or more Venturi tubes having a tangential inlet 5 for particle laden gaseous fluid and a scrubbed gas outlet 11 which may be shielded by a conical baffle 26 and a mist collector 17. Scrubbing fluid is fed through tangential nozzles 8 connected to a manifold 10 and through one or more valved nozzles 24. The scrubbing fluid supplied through the nozzle(s) 24 may be a gaseous coolant, e.g. part of the scrubbed gas discharged through outlet 11 and compressed and cooled before being recycled.