GB2110562A - Apparatus for treating mixtures of liquid and gas - Google Patents

Abstract

Apparatus for treating mixtures of liquid and gas, comprising an open- ended tubular element 2 of which the interior forms a separating space 3, inlet means for supplying a mixture of liquid and gas into the separating space 3, swirl imparting means comprising a plurality of vanes 4 for imparting a rotary movement to the mixture of liquid and gas to separate the liquid and the gas, and outlet means for separately discharging the liquid and the gas from the separating space 3. The apparatus is provided with a deflecting element 6 for directing the mixture of liquid and gas supplied through the inlet means towards the periphery of the swirl imparting means, said deflecting element 6 being located in or near the centre of the swirl imparting means. Liquid exits via 5 and gas via the top of cylinder 2. The device may be fitted in a contactor tray 9. <IMAGE>

Description

SPECIFICATION Apparatus for treating mixtures of liquid and gas The invention relates to an apparatus for treating mixtures of liquid and gas, comprising a normally vertically extending open-ended tubular element of which the interior forms a separating space, inlet means for supplying a mixture of a liquid and a gas into the separating space, swirl imparting means inside the separating space for imparting a rotary movement to the mixture of liquid and gas to separate the liquid and the gas, and outlet means for separately discharging the liquid and the gas from the separating space, the swirl imparting means being formed of a plurality of vanes substantially equally distributed over the cross-section of the separating space.

The term gas is taken throughout the specification and the claims also to include vapour.

Apparatuses of the above-mentioned type are suitable for use in columns for separating liquid/gas mixtures, as well as in columns for contacting liquid with gas for obtaining an exchange of matter and/or heat between the two fluid phases, followed by a separation of the phases.

When such an apparatus is used for contacting liquid with gas, the apparatus is provided with a mixing chamber having separate liquid and gas inlet means. In the mixing chamber the liquid is atomized in the supplied gas stream so that matter and/or heat can be exchanged between the liquid and the gas. The obtained mixture of liquid and gas is subsequently supplied to the swirl imparting means of the above apparatus for separating the liquid from the gas stream.

Apparatuses of the above-mentioned type are widely used in the oil and chemical industry, and are for example described in British patent specifications 1,055,913 and 1,172,680.

The object of the present invention is to provide an apparatus for treating mixtures of liquid and gas, which apparatus has a higher separating efficiency even at high liquid loads and/or high flow velocities than the known apparatuses for treating mixtures of liquid and gas.

The apparatus for treating mixtures of liquid and gas thereto comprises according to the invention a normally vertically extending openended tubular element of which the interior forms a separating space, inlet means for supplying a mixture of a liquid and a gas into the separating space, swirl imparting means inside the separating space for imparting a rotary movement to the mixture of liquid and gas to separate the liquid and the gas, outlet means for separately discharging the liquid and the gas from the separating space, the swirl imparting means comprising a plurality of vanes having areas increasing in outward direction and being substantially equally distributed over the cross-section of the separating space, wherein the apparatus is further provided with a deflecting element for directing the mixture of liquid and gas supplied through the inlet means towards the periphery of the swirl imparting means, said deflecting element being located in or near the centre of the swirl imparting means.

By the arrangement of a deflecting element in the separating space at the level of the vane assembly a liquid/gas mixture introduced in said space is urged to flow away from the centre of the vanes towards those parts of the vanes imparting the major part of the swirl action to the mixture of liquid and gas. Further the deflecting element gives an initial velocity in outward direction to the liquid droplets in the mixture resulting in a preseparation of the liquid and gas prior to reaching the main part of the vanes, where the main separation between liquid and gas takes place.

The above two main effects of the deflecting element result in a considerable enhancement of the separating action of the vanes. It has been found that this improvement in the separating efficiency of the apparatus is not attended with an inadmissible increase of the pressure drop over the vanes.

The invention will now be described by way of example with reference to the accompanying drawings, wherein: Figure 1 shows a vertical section of a first embodiment of the invention; and Figure 2 shows a vertical section of a second embodiment according to the invention.

It should be noted that identical elements shown in the drawings have been indicated with the same reference numeral.

In Figure 1, item 1 represents an apparatus for separating mixtures of liquid and gas, hereinafter also called "swirl tube", mounted in an opening of a tray 9. Swirl tube 1 comprises a tubular wall 2 enclosing a separating space 3 open at the lower end and at the upper end. The separating space 3 is provided with swirl imparting means formed by a plurality of inclined vanes 4 substantially equally distributed over the cross-section of said separating space 3. The part of the tubular wall 2 arranged above the vanes 4 is provided with a plurality of liquid discharge openings 5 substantially equally distributed over the circumference of the tubular wall 2.The swirl tube 1 is further provided with a hollow conically shaped deflecting element 6 having its apex pointing towards the upstream end of the separating space 3 and arranged on the longitudinal axis of the separating space 3 in the centre of the swirl imparting means. The deflecting element 6, being open at its upper end, is secured to the vanes 4 for example by means of welding. As shown in Figure 1, the half apex angle a of the deflecting element 6 is equal to the angle of inclination of the upper ends of the vanes 4 with the vertical. The area of the base of the deflecting element 6 is suitably chosen at least 25 percent of the cross-sectional area of the separating space 3.

During operation of the swirl tube 1, a gas/liquid mixture is supplied to the separating space 3 via the open lower end thereof. In the separating space 3 the flow of the gas/liquid mixture is deflected outwardly upon arriving at the deflecting element 6. As a result thereof the gas/liquid mixture gets a horizontal velocity component. Subsequently, the gas/liquid mixture impinges on the wider outer part of the inclined vanes 4 and obtains a rotary movement. The liquid droplets in the gas/liquid mixture are flung outwardly and impinge and coalesce on the inner surface of the tubular wall 2 and leaves the separating space 3 via the liquid discharge openings 5. The gas leaves the separating space 3 via the upper end thereof.

Reference is now made to Figure 2 showing an alternative of the apparatus shown in Figure 1.

The swirl tube 1 is at its lower end provided with a mixing chamber 10 formed by an extension of the tubular wall 2. For the supply of liquid into the mixing chamber 10 a plurality of liquid supply openings 1 1 are arranged in the lower part of the tubular wall 2.

To separate the liquid treated by the swirl tube 1 from the liquid to be introduced in the mixing chamber 10 a wall 12 is arranged around the swirl tube 1 above the liquid supply openings 11. The separating space 3 is provided with a deflecting element 13 arranged at the level of the inclined vanes 4. The deflecting element 13 being solid and conically shaped is secured to the upper ends of the vanes 4. An inverted conically shaped element 14 is arranged on top of the deflecting element 13 in such a manner that the two elements 13 and 14 have a common base. The area of said base is at least 25 percent of the cross-sectional area of the separating space 3.

During operation of the apparatus shown in Figure 2, gas is introduced into the mixing chamber 10 via the open lower end thereof, whereas liquid to be contacted with the gas for heat and/or matter exchange is introduced via the liquid supply openings 12. In the mixing chamber 10, the liquid is atomized in the supplied gas stream and a mixture of liquid droplets and gas is formed allowing the exchange of matter and/or heat between the liquid phase and the gas phase.

The mixture enters the separating space 3 where the liquid is subsequently separated from the gas by the action of the deflecting element 13 and the vanes in the same manner as described with reference to Figure 1. The inverted conically shaped element 14 acts during operation as a socalled vortex finder. The element 14 namely controls the vortexes occurring in the fluid stream above the vanes 4, to prevent undesired turbulence in the separating space 3 which turbulence might interfere with the swirl imparting action of the vanes 4. Instead of a conical shape, the element 14 may have any other suitable tapering shape.

To facilitate insertion of the deflecting elements 6, 13, the tops of the cones forming said elements may be cut off.

It should be understood that the present invention is not restricted to the application of a conically shaped deflecting element. Any other shape of deflecting element tapering towards the centre of the swirl imparting means may be applied.

Further, the invention is not restricted to swirl tubes of the types shown in the drawings. The deflecting element according to the invention may for example be applied in a swirl tube of the kind as described in British patent specification 1,123,546 or of the kind described in co-pending British patent application 8030134.

Claims (8)

1. Apparatus for treating mixtures of liquid and gas, comprising a normally vertically extending open-ended tubular element of which the interior forms a separating space, inlet means for supplying a mixture of a liquid and a gas into the separating space, swirl imparting means inside the separating space for imparting a rotary movement to the mixture of liquid and gas to separate the liquid and the gas, outlet means for separately discharging the liquid and the gas from the separating space, the swirl imparting means comprising a plurality of vanes having areas increasing in outward direction, substantially equally distributed over the cross-section of the separating space, wherein the apparatus is further provided with a deflecting element for directing the mixture of liquid and gas supplied through the inlet means towards the periphery of the swirl imparting means, said deflecting element being located in or near the centre of the swirl imparting means.

2. Apparatus as claimed in claim 1. wherein the deflecting element tapers towards the centre of the swirl imparting means.

3. Apparatus as claimed in claim 2. wherein the deflecting element is formed by at least part of a cone having an apex pointing towards the inlet means.

4. Apparatus as claimed in claim 3. wherein the apex of the cone is substantially arranged in the centre of the swirl imparting means.

5. Apparatus as claimed in claim 4, wherein the half apex angle of the cone is substantially equal to the angle of inclination of the vanes with the vertical.

6. Apparatus as claimed in any one of the claims 2-5, wherein the area of the base of the deflecting element is at least 25 per cent of the cross-sectional area of the separating space.

7. Apparatus as claimed in any one of the claims 2-6, wherein the deflecting element is provided with a tapering element having a base coinciding with the base of the deflecting element.

8. Apparatus for treating mixtures of liquid and gas, substantially as described with particular reference to the accompanying drawings.