NZ210910A

NZ210910A - Separating gases using stationary acoustic waves

Info

Publication number: NZ210910A
Application number: NZ210910A
Authority: NZ
Inventors: H Willot
Original assignee: Soredi Soc Rech Dev Ind
Priority date: 1984-01-24
Filing date: 1985-01-23
Publication date: 1987-09-30
Also published as: FI850284L; FI850284A0; EP0153290A1; AU3798885A; BE898745A; ES8700576A1; DK21485D0; DK21485A; ES539771A0; ZA85465B; PT79851B; PT79851A; OA07937A; JPS60238125A; BR8500293A

Description

2109 1 0 Priority Date(s): ... ."^.'7/. *.

Complete Specification Filed: •? 3 Class: "3 O SEP 1987 Publication Date: P.O. Journal, No: .f.P.ZP. 3* .

^ JAN 1985 ^fleCT/VEL Patents Form No.

NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION "PROCESS AND APPARATUS FOR SEPARATING A MIXTURE OF FLUIDS" I, WE SOCIETE DE RECHERCHES ET DE DEV3LOPPEMENT INDUSTRIEL S.A., a Belgian Company, of Chemin des Crolis, 4 -1470, Glabais/Genappe, Belgium, hereby declare the invention, for which I/we pray that a patent may be granted to me/us, and the method by which it is to be performed, to be particularly described in and by the following statement (followed by page 1A) f 2109 10 - 1 A- PROCESS_AND_APPARATUS_FOR SEPARATING_A_MIXTURE °*L?kyiDs BACKGROUND OF_THE_INVENTION FIELD_OF_THE_INVENTION This invention relates to a process for separating a mixture of fluids, entrained, in a subsonic flow, by a supply conduit, across a plurality of axisymmetric cavities comprising at least 5 one resonance cavity for defining, between an inlet and an outlet, stationary acoustic waves of different oscillation frequencies.

This process enables gaseous constituents to be separated even if the p hysical and chemical properties 10 thereof are similar. Only one of the properties needs to be different. The physical parameter which allows the constituents to be characterised and to be distinguished from each other may be the molecular weight, the polarity, the viscosity and/or the 15 calorific conductibility coefficient.

The principal application of this invention is in the production of pure gases, the purification of gaseous mixtures, the purification of air, pollution control, the removal of S02 from gaseous effluent and the removal of 20 radioactive elements and particles from the environment. 2 1091 It also permits the enrichment of a partial flow with a larger proportion of one of the constituents. A conventional example consists of isotope separation, inter alia for the enrichment or uranium.

This isotope separation has hitherto generally been effected by gaseous diffusion across a semipermeable wall at the base of larger installations.

However, other processes, particularly aerodynamic processes, have recently been developed by different 10 industrialised countries to guarantee their independance with regard to the supply of enriched uranium. 25§£5ZP£J9N_OF_THE_prior_ART The best known processes include in particular the processes based on the principle of - Becker's separation nozzle; - the Ranque tube (or Hilsch tube); - centrifuges; - the separation probe by impact effect, according to Fenn, claimed in US Patent No. 3,4 6 5,500; ^ - acoustic cavities, according to Zenner and Yendall described in US Patent No. 3,109,721 - vibrating bar according to Eisenkraft which is the subject of US Patent No. 4,197,094; - differential velocity deviation by Anderson; - separation by Campargue invasion. 21091 There are few similarities between the various processes given above. However, the fundamental principl of molecular separation resides in subjecting a plurality of gaseous molecules to specific accelerations using a force field derived from stationary acoustic pressure waves or a centrifugal force field, so as to modify the population density of certain constituents in particular sections of an enclosed space.

These known processes suffer from the common problems of the coefficients of separation of the various constituents being insufficient, the specific energy consumptions being too great and the complexity of the installations.

The aerodynamic process using the Becker separation nozzle makes use of the pressure gradient created in a deflected supersonic flow. The deflection of the flow in a curved nozzle produces a pressure gradient enabling the isotopes to be separated due to the different diffusion thereof, that is by barodiffusion. The heavy molecules are concentrated in the vicinity of the outer deflecting wall. A divertor then separates the flow into fractions, one of which is enriched with light gases, and the other with heavy gases.

This process is for the most part developed from aerodynamic processes. 2109 t This process has given rise to numerous variants which still form the subject of theoretical and experimental studies. The following are the most important variants: - double deflection separation; - double deflection separation using deflector gas; - double feed separation; - separation by opposing jets.

However, all these processes are still a long way 10 from replacing the conventional processes of gaseous diffusion and ultracentrifugation for isotope separation.

An obtuse or round-pointed obstacle is provided in the axis of a supersonic jet in the separation probe device using impact effect according Fenn, for 15 separating certain constituents of gaseous mixture. In fact, a detached wave is formed upstream of this obstacle. The trajectory of different molecules of gas crossing such a shock wave thus depends on the physical and chemical properties thereof. The central 20 zone of the shock wave, formed directly in front of the obstacle is enriched with heavy molecules which maybe removed by an axial channel provided in the obstacle.

The main disadvantage of the probe separation 25 process is the poor partition coefficient value, defined as the ratio between the flow crossing the probe (heavy fraction) and the flow entering, which forms the jet. 21^9 1 The cross-section of the axial channel of the obstacle, which may consist of a pitot tube, is negligible with respect to the cross-section of the conduit for supplying the gaseous mixture, such that the yields 5 of the operation can only be extremely poor, even if several obstacles are provided in the same conduit.

Furthermore, this process can only be applied to a mixture consisting of only two gaseous constituents.

The method of separation in an acoustic field 10 according to G.H. Zenner and C.F. Yendall, described in US Patent No. 3,109,721, operates with a sealed chamber of conical shape, provided with an acoustic source fixed at the summit of the cone . The base of this conical chamber is provided with a spherical surface 15 which serves to reflect the acoustic waves. By selecting a suitable oscillation frequency, it is possible to create, by resonance, due to the stationary waves, a substantial acoustic pressure field in relation to the intensity of the source.

In the afore-mentioned chamber, the acoustic intensity increases from one end to the other. It is poor in the vicinity of the spherical reflector and intensifies in the vicinity of the source. This intensity gradient enriches the zone adjacent to the 25 reflector with heavy constituents and the zone adjacent to the source with light constituents. 210910 However, this known process suffers from the major disadvantage of not being capable of providing sufficient quantitative yields. The poor yields which are obtained can be explained by the fact that the zones of enrichment are created in a longitudinal direction, while the supply of unused gas and the sampling of an enriched partial flow are effected in a transverse direction. Consequently, this arrangement continually creates an imbalance. This therefore becomes an unstable system which only permits the separation of relatively insubstantial throughputs. Eisenkraft's vibrating bar suffers from problems similar to those of the preceding method, and furthermore, it can only be applied for the separation of binary mixtures. BRIEF SUMMARY OF THE INVENTION This invention sets out to overcome the aforementioned problems. This invention proposes a process which permits the zone of enrichment to be staggered in the direction of the gaseous flow, thereby ensuring a stable equilibrium, and permits substantial throughputs.

This invention provides a process for separating a fluid mixture comprising at least one compressible component entrained in subsonic flow by a supply conduit across a set of axisymmetric cavities comprising at least one resonance cavity for beginning between an inlet and an outlet stationary acoustic waves of different oscillation frequencies, comprising: (a) creating an annular outflow of said fluid, by directing the throughput of gas onto an aerodynamically shaped central core of a first inlet neck; (b) creating a recirculation zone in a diverging section of the supply conduit thereby producing toroidal vortices in said gas; (c) compressing the vortices in said fluid thereby increasing the rotational speed of the vortices; (d) producing waves from vortices and the outflow of fluid; (e) amplifying the waves; and (f) producing stationary acoustic waves of varied frequency which contribute to formation and detachment of the vortices from the zone of recirculation thereby creating an acoustic pressure field which favours the separation of various constituents of the fluid mixture, while at the stationary acoustic waves, a separation effect is superposed, creating annular layers which are enriched with at least one constituent of the fluid mixture.

According to a further feature the invention further comprises creating a second vortex which is paraxial to the first, thereby displacing the outflow so 21091 as to facilitate the reflection of stationary waves. A low pressure zone is advantageously created along the first central core of aerodynamic shape which is capable of producing a break-down of the annular flow far from the walls of this body, which the low pressure zone establishes a zone of recirculation along the said walls.

This invention also relates to an apparatus for carrying out the aforementioned process. This apparatus is essentially characterised in that it comprises an apparatus for separating a fluid mixture comprising at least one compressible component entrained in subsonic flow by a supply conduit, across a set of axisyrranetric cavities comprising at least one resonance cavity for defining between an inlet and an outlet stationary acoustic waves of different oscillation frequencies, said apparatus comprising: (a) a means for moving the fluid mixture to be treated in a circuit; (b) a supply conduit for regulating the throughput of fluids, said supply conduit communicating with said means for moving the fluid mixture; (c) an inlet neck provided with an aerodynamically-profiledcentral core, in communication with and downstream of said supply conduit; (d) a chamber for supporting the central core, said central core in communication with and downstream of the inlet neck; (e) said chamber containing a set of axisymmetric cavities comprising at least one resonance cavity, the - 9 - , 210910 walls of which are profiled so as to produce a break-down of an annular stream distant from the outer walls of the cavity and thereby to create, under the influence of a acoustic waves, in/zone of recirculation, toroidal vortices which are entrained along the outer walls of the cavity by the annular outflow, in the direction of the flov (f) a contraction zone in communication with and downstream of said chamber; (g) a second neck in communication with and downstream of said contraction zone; (h) a second cavity in communication with and downstream of said second neck; (i) an outlet neck in communication with and downstream of said second cavity, the periphery of the outlet neck being provided with annular traps; and (j) a second central body which is or is not surrounded by a concentric annular body in which there are provided annular traps and are or are not provided a central channel, said second central body being in communication with and downstream of said outlet neck; and wherein a dryer is or is not present, said dryer being communicated with said means for moving the fluid mixture; and wherein there is or is not provided a filter capable of removing particles of predetermined dimensions from the fluid mixture to be treated, said filter being in communication with and upstream of said dryer or said means for moving the fluid mixture to be treated if said dryer is not present.

Other characteristics, details and advantages of the invention will emerge from the following detailed description of a particular embodiment of the invention. 2 109 1 n §5I51LP§SCRIPTION_OF_THE_SEyERAL VIEWS_OF THE_DRAWINGS - Figure 1 is a general diagram of the apparatus according to the invention; - Figure 2 illustrates the formation of toroidal vortices 5 in a nozzle according to the invention; - Figure 3 is a longitudinal section of the set of undulators assembled in series as shown in Figure 1; - Figure 4 shows an additional resonator; - Figure 5 is a detailed section of one of the lO undulators, and - Figure 6 illustrates the creation of a magnetic field in an undulator.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The same reference numerals designate similar elements in different figures.

The entire apparatus shown in Figure 1, designated by reference numeral 1, comprises two undulators, 2,3, each of which is provided with various cavities 4,5, 6,7,7' arranged one after the other and connected J 20 by necks 8,9,10 and 11 and means 12 permitting a flow of air, which has optionally been dried and purified, charged with any gaseous constituents to be separated, and to be discharged.

/ These means 12 comprise, in a particular embodiment of the invention, a turbine, a ventilator or a volumetric 3 compressor ensuring a throughput of 200 Nm /h under a 210910 - ii - pressure of 1220 millibars absolute. The air drawn in from the environment is optionally filtered and dried.

Sulphur dioxide tapped from a steel cylinder 13, ,14 is metered in using a flow -meter/and injected into a tail pipe 15, positioned upstream of the turbine 12.

The throughput of gas mixture to be treated is regulated in the supply conduit 16 which has a diameter^ * of 300 mm and a length of 3 metres.-. In this supply conduit 16, the flow of gas is subjected to a turbulent outflow and is directed towards the inlet neck 17 of the central core of the aerodynamically-profiled annular shaper 18 which is positioned in the axis of the said inlet neck 17. The central core of the annular shaper has a central channel 19 which permits the frontal pressure at the inlet of the undulator 2 to be harnessed.

The inlet velocity of the gaseous flow in the supply tube preceding the inlet neck 17 is 15.25 metres/ second. The central core of the annular shaper is designed to form an annular flow and to modulate this flow by several pressure reductions before conveying it into the undulator 2 itself at a speed on 132 metres/second. A variation in velocity of the order of 20% is allowable.

The undulator 2 comprises a tranquillizing chamber 20 provided with transverse fins 21 for holding in place the central core of the annular shaDer 18. 9 o: (W 210910 The acceleration neck 17 opens into a cavity 4 through a flared portion 22 which causes the separation of the flow so as to create a recirculation zone which produces torodial vortices 26.

The axisyinmetric profile of the undulator 2 causes the formation of vortices in the gaseous flow. These vortices rotate in a clockwise or anti-clockwise direction i i depending on whether they are along the outer walls of the annular shaper 18 or along the central axis of the nozzle. A contraction 30 compresses the vortices at the outlet of the first nozzle, thereby substantially increasing their rotational speed until they enter the tranquilizing chamber 5. As the diameter of the tranquilizing chamber 5 is small, very substantial pressure gradiants are obtained.

It can also be seen in the tranquillizing chamber 5 that the variation in resistance to the flow of the vortices causes, by a pumping effect, an acoustic wave which develops towards the inlet of the first acoustic cavity 4 where it feeds and regulates the formation of vortices.

The acceleration of;the vortices amplified by the acoustic pressure causes the migration of heavy gases towards the periphery of the vortices. The different constituents of the gas are thereby separated and need only be drawn off by notches provided on the wall of the nozzle or in the central flow zone. 210910 For this purpose, the annular flow obtained at the outlet of the first undulator is projected by an acceleration neck 9 into the second undulator 3.

The acceleration neck 9 is provided with a sharp- edged divertor 28 which is designed to create a wave.

It opens through a diffusor 23 into a cavity 6 having an aerodynamic profile, which diffusor is capable of producing a break-down of the annular flow remote from the wall of the diffusor 23, which performs the task of acoustic parabol contributing to create stationnary waves.

Indeed, along the wall of the diffusors 22 and 2 3 and the further away one moves from the change in cross-section, the more abrupt this change becomes, and there is an increase in pressure and a drop in speed; the 25 fluid molecules in contact with the wall finish with insufficient energy to overcome the positive pressure gradient; they become stationnary or move backwards, thereby creating recirculating zones.

Thus, along the walls of the cavities 4 and 6, are 2Q produced zones of toroidal recirculation which produce 'w' toroidal vortices 26 which, under the combined effect of the acoustic waves produced at 5, 7, and 24, move along the walls of the undulators 2 and 3.

^ The tranquillizingzone 27 protects the fins 28, ^ ^ *-n the form of a cross for example, which support the central core 20. The average speed of the entire volume of the annular flow is llm/s at this point (Fig. 4). iMxmjMi/WNtSi 2109 1 0 The contraction zones 30, 31 produce an acceleration of the central stream of the outflow which increases from 15.25 m/s to 106.5 m/s in the necks 32 and 33. This acceleration is associated with a concentration of the vortices. Owing to the conservation in the amount of movement, the rotational speed gradually increases up to cavities 5 and 7, where the vortices slow down. The cavities 5 and 7 are profiled in such a manner that the intermittent variations of the outflow in this zone produce acoustic waves of high intensity. These end at the outflow necks 8 and 10 in the vicinity of which annular nappes enriched with one or more constituents are selectively taken, using traps 34 provided in the periphery of the outer wall of the chamber, on the surface of a second central body or an annular body positioned concentrically with respect to this second central body.

By halving the spacing in the chamber, the central body prevents the production of interfering acoustic waves in a transverse direction perpendicular to the axis of the chamber.

The lighter gases are recovered by annular vents or by notches.

It may be advantageous to provide annular shapers 29 and 35 which are designed to introduce- a rr.agnetic field so as t o encourage the migration of certain molecules (Fig. 6). 2109 1 Example 1 A nozzle 1 having a profile similar to that shown in Fig. 1 is supplied with air containing from 1,700 to 318,000 ppni of SOj. This throughput is from 95 to 5 100 normal cubic metres per hour.

The SO2 is introduced in a foot pipe 15 for surrounding air from a steel cylinder 13 filled with concentrated SOj.

A plenum chamber with an inner diameter of 300mm 10 and a length of 3 m is positioned upstream and is connected to a turbine/ventilator which ensures the intake• and pulsation of the polluted air at a distance which may vary from 1.5m to several tens of metres, taking into account, of course, the capacity of the ventilator 15 and the registered losses of charge. This turbine injects the polluted gas into the entire cavity-undulator.

The content of SO2 at the inlet of the first undulator 2 is measured using a "Thetra-Sensor"apparatus based on the principle of voltametry.

The SO2 concentration of the gas mixture at the inlet of the first undulator 2 in a supply conduit 16 is selected during three distinct tests and is respectively 4,000 ppm (0.3 % by volume) in the firt test; 6,000 ppm (0.6 % by volume) in a second test; 318,000 ppm (31.8% by volume) in a third test; The first part of the sets of cavity-undulatuis is known as the "ring former" part 18 and has two function?: <PB\ 6\ 1. Harness the frontal pressure at the inlet of the cavity undulator 2. Form an annular flow while creating several pressure reductions on this annular flow before entering the undulator 1.

The inlet speed is 15 m/s, the outlet is 132 m/s under a pressure of 18,000 pascal, a variation of 20% of this pressure being accepted.

The same holds true for the variation in throughput which istalso 20%.

The second cavity-undulator has a separating fuction and comprises a diffusor, a cylindrical section supporting a cross which serves to support the central obstacle of the ring former , the speed at this point being 11 m/s and remaining unchanged up to the inlet of the .tranguilizing section of the undulator which brings the speed to 90 m/s and which accelerates the flow to a speed at a-first neck of 106 m/s so that it enters the cavity at an average speed of 15 m/s. It undergoes an acceleration in the outflow neck 8,10, just in front of the divertor 24, to a speed of 126.6 m/s for reaching the necks 9 and 11, a speed of 152.5 m/s. The second undulator has the same characteristics as the first undulator, although a loss in volume of from 1 to 10 %, due to the divertors has to be accounted for in the calculations; the passage sections have therefore to be adapted in order to maintain the same speeds. 210 9 1 ® The SC>2 content of the purified air at the outlet of the reactor is measured using a "Thermo electron" apparatus based on the principal of pulsated UV fluorescence .

The SC>2 concentrations measured at the outlets of the purifiers are determined, after being sampled in "radlar" sacks, by oxidative micro-coulometry.

During the test, the SC^ concentration of the purified air at the outlet was outside the limit of lO detection of the "thermo Electron" apparatus. This liir.it of detection is 50 ppb.

S02 content of the gas INLET OUTLET OF THE REACTOR 4000ppm less than 50 ppb 6000ppm less than 5 ppm 318000ppm less than 0... 3 ppm The carrier gas, in this case air, issues almost 20 pure while the carried gas, that is the SO2 for the first undulat is charged with about 10% of its own volume. By re-injecting the latter, as a carrier gas into a second nozzle, it is possible to obtain a greater degree of purity.

By the undulator, the total loss of throughput 25 is about 2% and equals the quantity of test gas sampled to eliminate the 4,000 ppm ox SO2. The effect of multiple separation in cascade is obtained by aligning revcral undulators in series as in Exsjr.ple 3.

J <S (f> 9 * A A test was carried out using a series of 10 consecutive undulators each of which samples some of the sulphurous anhydride mixed in a flow. This operation enabled a pollution control to be obtained, the yield of which was controlled by agreed organisms and which achieves 99.99% of yield of separation with an extraction of 35% of the volume entering of sulphurous anhydride.

The outlet of the last cavity-undulator provided with a 5 m long tube connected at its end enabled samples to be made. The measuring point was at the outlet end of the inlet plenum chamber.

The' treatment and pollution-controlled air is sampled at the centre of the plenum chamber of the outlet at a spacing of 3 metres from the end.

These tests were carried out several times.at different temperatures, from 0 to 150°, without there being any fundamental changes in the results.

The only adjustment to be made was the frontal pressure of the inlet of the cavity-undulator. The efficiency of separation is not influenced by different tygrometric degrees. The SO., which has thus been separated can be conveyed by tubes having an inner diameter of 4mm up to distances of 6 m in blowers so as to neutralize the S0_. — i ' i. ■ njWf I # o r- to In particular tests, good results were obtained by providing additional resonators in the extension of the resonance cavity.

A particular embodiment of an additional resonator 5 36 consists of a vase or a bell provided with very thin walls. The inner volume forms a resonance volume with a depth approximately corresponding to a fraction of the fundamental vibration wavelength (c.f. Fig. 3).

The various constituents which form the concentric 10 annular streams are separated by means of divertors or by means of traps positioned at several places on the cavity on the periphery of the outer walls or of a central or concentric annular body.

Example 2 An industrial prototype operating in the SOPAR plant at Sart-Dames-Avelines was produced for a gas 3 throughout equal to 5000 Nm /h with a tolerance of more or less 10% on the throughput.

A mixture of air charged with 5,644mg/m"* of 20 dichloromethane and 3,464 mg/m^ of isopropanol at a temperature of 39. 4 "C is conveyed by means of a ventilator-suDercharger provided with four turbines in an apparatus similar to that shown in Fig.l. The separated dichloromethane, leaving enriched the main reacior, is injected in an incinerator and the so produced hydrochloric acid is on its turn separated from the combustion gases by means of a second reactor working at temperatures of more than 400°C, in order to be then diluted by bubbling and stocked. 2109 ^ At the outlet of the main reactor, the purified air is only charged with 566 mg/m3 of dichloromethane, 1011 gm/m3 of isopropanol.

The separation yields expressed in % are therefore: - for dichloromethane : 90% - for isopropanol : 4 8% for acetone : 80% For the matter of the yield of the second reactor for enrichment and separation of hydrochloric acid, it is 99.99%, this reactor working at the nominal throughout provided by construction.

The application of the aforementioned apparatus are manifold and particularly concern the chemical and pharmaceutical industries, nuclear science, medicine and hospitals.

The following are some examples of the applications of the apparatus: - the separation of CO from air; - the recovery of C02, S02, NOx and CO in industrial exhaust fumes inter alia from thermal power stations; - the removal of solvents, such as acetone, dichloromethane and isopropanol in a vent - incineration and recuperation; - the production of CO for the chemical industry; - the removal and recovery of carbon disulphide in vents from the production of viscose; - production of air enriched with oxygen; - production of hydrogen by enriching cracking gas of coke gas; - production of methane and elimination of CO and H2S; - separ a Lion of air and product! or, of O2 and N2 ; 2 © - production of rare gas; -—production of—CO for preparing phoegen; - enrichment of gases from coal-gaseification; - isotopic separation of uranium; - elimination of radio-activity from air by separating radio-active gases carrying optionally particles; - production of heavy water; - the isotope separation of uranium; - the elimination of radio-actovoty in air by separating the radio-active gases which optionally carry particles; - preparation of a sterile air containing a particular agent with a view to: treating allergies, treating asthma or immunological treatment, treatment of chronic diseases, 15 climatotherapy; - creation of clean rooms, that is completely sterile preparation chambers for improving the environment of inocculating devices; - supply of pure air; - enrichment of HF; —rocuporation—and enrichment—&£—HF contained in water; - anti-pollution device for vehicles; - accidentally depollution installation .

The gas S O O 3 T~ ci t. i O fj process can also be used for 25 ded-jst ing, granulomotry and the purification of liquid in vapour phase.

The efficiency of the afore-mentioned apparatus has been verified by different tests.

Noise level measurements were taken around the reactor using a static noise level analyser "BRUEL and KJAER". This noise level is about 63.0 dB(A) at a distance of 50 m from the reactor, unprovided with acoustic protection.

The afore-mentioned examples describe the use of throughputs of gas of from 100 to 5000 Nrr^/H. The process can, however, be extended to far more substantial gas throughputs, thereby making its industrialization very straight forward in a large number of fields.

The energy consumption is low and solely results from the loss of charges of from 10 to 20% of the gas, initial pressure being 100 to 200 mbars above the atmospheric pressure.

It is clear that the invention is not exclusively limited to the embodiment shown and that modifications may be made to the shape, arrangement and compositon of some of the elements used in the design, without departing from the scope of the invention.

Thus the efficiency of separation and the selection of components to be sampled may be influenced as required by modifying the capacity of the emitting cavities 5, 7 and the position of the gap traps 34. ) 1109 The apparatus does not comprise any movable mechanical part other than the supercharger. A plurality of cavities may be placed in series thereby permitting the yield of a separating apparatus to be increased.

O ^ The apparatus preserves its efficiency even if the staked pressures and temperatures are high, under the condition that the expansions occur outside the circuits of the reactor. 210910

Claims

WHAT WE CLAIM IS:

1. A process for separating a fluid mixture comprising at least one compressible component entrained in subsonic flow by a supply conduit across a set of axisymmetric cavities comprising at least one resonance cavity for beginning between an inlet and an outlet stationary acoustic waves of different oscillation frequencies, comprising: (a) creating an annular outflow of said fluid, by directing the throughput of gas onto an aerodynamically shaped central core of a first inlet neck; (b) creating a recirculation zone in a diverging section of the supply conduit thereby producing toroidal vortices in said gas; (c) compressing the vortices in said fluid thereby increasing the rotational speed of the vortices; (d) producing waves from vortices and the outflow of fluid; (e) amplifying the waves; and (f) producing stationary acoustic waves of varied frequency which contribute to formation and detachment of the vortices from the zone of recirculation thereby creating an acoustic pressure field which favours the separation of various constituents of the fluid mixture, while at the stationary acoustic waves, a separation effect is superposed, creating annular layers which are enriched with at least one constituent of the fluid mixture.

2. A process according to claim 1, further comprising /•''V thereby displacing the outflow so as to facilitate the creating a second vortex which is paraxial to the firsto reflection of stationary waves. \ 17 AUG 1987 - 25 - 2 1 09 1 0

3. A process according to claim 1, wherein low pressure fields are created along the first central core of aerodynamic shape which is capable of producing a breakdown of the annular flow distant from the walls of this body, which fields produce a zone of recirculation along the said walls.

4. A process according to Claim 1, further comprising creating low pressure fields which produce a zone of recirculation along the walls of the supply conduit.

5. An apparatus for separating a fluid mixture comprising at least one compressible component entrained in subsonic flow by a supply conduit, across a set of axisymmetric cavities comprising at least one resonance cavity for defining between an inlet and an outlet stationary acoustic waves of different oscillation frequencies, said apparatus comprising: (a) a means for moving the fluid mixture to be treated in a circuit; (b) a supply conduit for regulating the throughput of fluids, said supply conduit communicating with said means for moving the fluid mixture; (c) an inlet neck provided with an aerodynamically-profiled central core, in communication with and downstream of said supply conduit; (d) a chamber for supporting the central core, said central core in communication with and downstream of the inlet neck; (e) said chamber containing a set of axisymmetric cavities comprising at least one resonance cavity, the walls of which are profiled so as to produce a break-down of an annular stream distant from the outer walls of the i - 26 - 210910 % cavity and thereby to create, under the influence of acoustic waves, in a zone of recirculation, toroidal vortices which are entrained along the outer walls of the cavity by the annular outflow, in the direction of the flow; (f) a contraction zone in communication with and downstream of said chamber; (g) a second neck in communication with and downstream of said contraction zone; ^0 (h) a second cavity in communication with and down stream of said second neck; (i) an outlet neck in communication with and downstream of said second cavity, the periphery of the outlet neck being provided with annular traps; and 15 (j) a second central body which is surrounded by a concentric annular body in which there are provided annular traps and is provided with a central channel, said second central body being in communication with and downstream of said outlet neck; and wherein a dryer is present, 20 said dryer being communicated with said means for moving i^i the fluid mixture; and wherein there is provided a filter capable of removing particles of predetermined dimensions from the fluid mixture to be treated, said filter being in communication with andupstream of said dryer.or caid means-L2.5 -for moving—Lhe fluid mixture to be treated if said dryor- i-s noL jJiUL.unL'v

6. An apparatus for separating a fluid mixture comprising at least one compressible component entrained in subsonic flow by a supply conduit, across a set of axisymmetric cavities comprising at least one resonance cavity for ■i t ' Oil mi! 1 17 Ay g 1987 ^ <** * . 27 . 210910 m defining between an inlet and an outlet stationary acoustic waves of different oscillation frequencies, said apparatus comprising: (a) a means for moving the fluid mixture to be 5 treated in a circuit; (b) a supply conduit for regulating the throughput of fluids, said supply conduit communicating with said means for moving the fluid mixture; (c) an inlet neck provided with an aerodynamically-10 profiled central core, in communication with and downstream of said supply conduit; (d) a chamber for supporting the central core, said central core in communication with and downstream of the inlet neck; 15 (e) said chamber containing a set of axisymmetric cavities comprising at least one resonance cavity, the walls of which are profiled so as to produce a break-down of an annular stream distant from the outer walls of the 20 Is! CO cavity and thereby to create, under the influence of acoustic waves, in a zone of recirculation, toroidal r- \ ^,1 vortices which are entrained along the outer walls of O • \ the cavity by the annular outflow, in the direction of ^ \ the flow; (f) a contraction zone in communication with and downstream of said chamber; (g) a second neck in communication with and downstream of said contraction zone; (h) a second cavity in communication with and downstream of said second neck; (i) an outlet neck in communication with and downstream of said second cavity, the periphery of the outlet neck being provided with annular traps; and - 28 - 210910 10 (j) a second central body which is provided with a central channel, said second central body being in communication with and downstream of said outlet neck; and wherein a dryer is present, said dryer being communicated with said means for moving the fluid mixture; and wherein there is provided a filter capable of removing particles of predetermined dimensions from the fluid mixture to be treated, said filter being in communication with and upstream of said dryer, or said moano-lui iiiuving- the—fluid minturo to be treated if diyfel is not pi^beiiLi

7- An apparatus for separating a fluid mixture comprising at least one compressible component entrained in subsonic flow by a supply conduit, across a set of axisymmetric cavities comprising at least one resonance cavity for defining between an inlet and an outlet stationary acoustic waves of different oscillation frequencies, said apparatus comprising: 20 (a) a means for moving the fluid mixture to be treated in a circuit; (b) a supply conduit for regulating the throughput of fluids, said supply conduit communicating with said means for moving the fluid mixture; (c) an inlet neck provided with an aerodynamically-profiled central core, in communication with and downstream '• \. of said supply conduit; A, (3) a chamber for supporting the central core, said I|<i5 i 17AUG" 3- central core in communication with and downstream of the y 30 inlet neck; (e) said chamber containing a set of axisymmetric ~ 29 - i 210910 i*- downstream of said chamber? cavities comprising at least one resonance cavity, the walls of which are profiled so as to produce a break-down of an annular stream distant from the outer walls of the cavity and thereby to create, under the influence of 5 acoustic waves, in a zone of recirculation, toroidal ^ vortices which are entrained along the outer walls of the cavity by the annular outflow, in the direction of the flow; 10 (f) a contraction zone in communication with and (g) a second neck in communication with and downstream of said contraction zone; (h) a second cavity in communication with and down-15 stream of said second neck; (i) an outlet neck in communication with and downstream of said second cavity, the periphery of the outlet neck being provided with annular traps; and (j) a second central body which is surrounded by 20 a concentric annular body in which there are provided annular traps and is provided with a central channel, said ^ second central body being in communication with and down stream of said outlet neck; and wherein there is provided a filter capable of removing particles of predetermined 25 dimensions from the fluid mixture to be treated, said filter being in communication with an upstream of caid- dryer or said means for moving the fluid mixture to be treated.-if ■oaid dryer io not present. I Aug J* ' - 30 - 210910

8. An apparatus according to any one of Claims 5 to 7, wherein one of the cavities is provided with a device, positioned around this cavity and/or in the central body and/or in an intermediate body, for creating a continuous or alternating electro-magnetic field.

9. An apparatus according to any one of Claims 5 to 7, wherein at least one resonator having very thin walls, in the shape of a bell, is positioned axially upstream or downstream of the resonance cavity and is for producing variations in frequency.

10. A process according to claim 1 substantially as herein described with reference to the accompanying drawings.

11. An apparatus according to claim 5 substantially as herein described with reference to the accompanying drawings. SOCIETE RECHERCHES ET DE DEVELOPPEMENT INDUSTRIE!, S.A. ■''&-1 " f' ~~:s\ (y- A jp WAUG198Z a