Process for Homogenizing Polyolefin Drag Reducing Agents

Abstract

According to the present invention there is provided fluidising apparatus comprising: a flow chamber 2 having a fluid inlet 4 and a fluid outlet 6; means 18 for establishing a swirling flow in a fluid passing out of the fluid outlet; and a transport outlet 30 for transporting fluidised material away from the flow chamber 2, the transport outlet 30 being situated externally of the flow chamber 2.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention and to show how it may be carried into effect, reference will now be made by way of example to the accompanying drawings, in which:—

FIG. 1 is a longitudinal cross-section through a fluidising apparatus;

FIG. 2 is a cross-section on line AA in FIG. 1;

FIG. 3 is a schematic representation of an atmospheric system using the fluidising apparatus of FIG. 1; and

FIG. 4 is a schematic representation of a pressurised system using the fluidising apparatus of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 and 2 illustrate a fluidising apparatus comprising a flow chamber 2 having a fluid inlet 4 and a fluid outlet 6. The flow chamber 2 comprises a housing in the form of a cap 8 having a side wall 10 and a top 12 which in the region 14 is generally in the shape of a cone with a concave side wall. The underside of the top 12 is provided with an annular recess 16 in which is located a cylindrical flow guide 18. As best shown in FIG. 2, the upper portion 20 of the flow guide 18 is provided with a series of tangential slots 22a to 22f. The lower portion 24 of the flow guide 18 has an external thread which cooperates with an internal thread formed in an annular flange 26.

A fluid outlet 6 is defined between the side wall 10 of the cap 8 and the flange 26 and an annular flow passage 28 is defined between the side wall 10 of the cap 8 and the upper portion 20 of the flow guide 18. The annular flow passage 28 is continuous with the fluid outlet 6, so that the fluid inlet 4 communicates with the fluid outlet 6 by means of the tangential slots 22a to 22f and the flow passage 28. Directly above the flow chamber 2 is located a transport outlet 30.

In use of the fluidising unit in a pressurised system, fluid under pressure enters the fluidising unit through the fluid inlet 4, passes down the flow guide 18 and exits the flow guide tangentially via the slots 22a to 22f (as the open end of the flow guide 18 is closed by the cap 8). The cap 8 also acts as a swirl enhancer and is positioned such that its side wall. 10 forms one side of the said annular flow passage 28 around the tangential slots 22a to 22f. The cap 8 is longer than the slots 22a to 22f, such that it overlaps the slots by an amount d and defines the fluid outlet 6 by which the concentrated swirling fluid exits the flow chamber 2. The profiled region 14 of the cap 8 is shaped in order to encourage a stable fluid regime above the flow chamber 2. The swirling flow exiting the flow chamber 2 fluidises, mixes and breaks up settled or partly settled solids adjacent to the flow chamber 2, thereby forming a mobile slurry, which is directed towards the transport outlet 30 from where it can be directed to a slurry pipeline or for further processing. The transport outlet 30 may, for example, comprise a substantially horizontal pipe or a pipe with a bend (preferably a 90 degree bend), and it may be funnelled, such that it flares outwardly towards the flow chamber 2.

The fluidising apparatus may be fixed within a vessel or tank at any orientation, passing through the vessel or tank wall by means of a normal flanged nozzle or threaded inlet boss, whereby the inlet to the fluidising apparatus is fed by a fluid under pressure. The outlet 6 of the fluidising apparatus sets up a swirl that can be created by, for example, a tangential fluid inlet or inlets, tangential slots or holes in a flow guide, or an auger unit within the inlet pipe or flow chamber 2. The swirl from the fluidising apparatus mobilises any settled or partly settled solids into a slurry mixture. In the case of a pressurised unit the only exit from the vessel is a separate transport outlet 30 which is preferably situated directly above or under the fluidising unit. The prepared slurry then reports via the transport outlet 30 to a slurry pipeline, pump or process system as may be required. In an atmospheric system the outlet duct can be attached to a pump, or inductor to create the pressure differential required to transport the slurry to its required destination.

FIG. 3 shows an atmospheric system incorporating a fluidising apparatus in accordance with the present invention.

Solids to be transported are loaded into V1. Should fluids be present in V1 these may be displaced by incoming solids and will report to the Tank T1 by means of an overflow.

When V1 is filled with solids the pump is started and the valve 40 opens to allow fluids to pass through non-return valve 42 into fluidising unit F1.

Solids will be fluidised and discharged through pipe 44, due to the vessel operating at atmospheric pressure the slurry will discharge at an equal or less pressure, controlled by the hydrostatic head of solids/water/slurry available in V1.

The discharging slurry can be fed into an inductor 46 to provide motive force to deliver the slurry over a short distance. Feed to the inductor may be from a separate feed or from the main pump by opening valve 48. Alternatively the exiting slurry from 44 may be fed into the suction of a slurry pump 50 to provide motive force without further dilution. Using this method will in most cases reduce the need for large mixing tanks normally required to feed slurry pumps.

FIG. 4 shows a pressurised system using a fluidising apparatus in accordance with the present invention.

Solids to be transported are loaded into the vessel via a hopper 58 and valve 60. Fluids in vessel V1 are displaced by incoming solids and report to the feed tank T1 via valve 62.

When the vessel is filled with solids, valves 60 and 62 are closed together with all other valves.

The pump is started and valve 64 is opened to allow fluid to pass non-return valve 66 and to enter V1 via fluidising unit F1 to pressurise V1 and solids will discharge as a slurry through the discharge line 68. Should the slurry be too dilute then valve 70 may be opened to cause partial flow to the top of vessel V1 to compact the solids and cause greater concentration of solids in the slurry discharge.

In the event that the slurry is too concentrated valve 70 is opened to cause the discharging slurry to be diluted to suite the process conditions. This can be pre-set or can be operated whilst slurry is discharging until the set point is reached.

Alternatively valve 70 may be automatic and opening set by using a signal from a mass density meter installed in the slurry discharge line.

Claims

1. A fluidising apparatus comprising: a flow chamber having a fluid inlet and a fluid outlet;means for establishing a swirling flow in a fluid passing out of the fluid outlet; anda transport outlet for transporting fluidised material away from the flow chamber, the transport outlet being situated externally of the flow chamber.

2. Fluidising apparatus as claimed in claim 1, in which the transport outlet is situated close to the flow chamber.

3. Fluidising apparatus as claimed in claim 1, in which the transport outlet is situated on a central axis of the flow chamber.

4. Fluidising apparatus as claimed in claim 1 in which the flow chamber is located with its central axis substantially vertical and the transport outlet is situated directly above or directly below the flow chamber.

5. Fluidising apparatus as claimed in claim 1 in which the said means for establishing a swirling flow comprises an offset fluid inlet with a central axis which does not intersect the central axis of the flow chamber.

6. Fluidising apparatus as claimed in claim 1 in which the flow chamber comprises a housing and a flow guide, the flow guide being situated at least partially within the housing.

7. Fluidising apparatus as claimed in claim 6, in which the housing comprises a cap which fits over the flow guide.

8. Fluidising apparatus as claimed in claim 6 in which the flow guide is substantially helical.

9. Fluidising apparatus as claimed in claim 6 in which the flow guide is substantially tubular and has a side wall in which is formed an opening.

10. Fluidising apparatus as claimed in claim 9, in which the opening extends through the side wall of the flow guide in a direction which is offset from a radial direction of the flow chamber.

11. Fluidising apparatus as claimed in claim 10, in which the opening extends substantially tangentially through the side wall of the flow guide.

12. Fluidising apparatus as claimed in claim 9 in which there are a plurality of openings formed through the flow guide.

13. Fluidising apparatus as claimed in claim 12, in which the openings are in the form of tangential slots.

14. Fluidising apparatus as claimed in claim 6 in which the flow chamber is closed off at its outlet end by an end wall.

15. Fluidising apparatus as claimed in claim 14, in which the end wall is supported on the flow guide and extends radially outwardly beyond the side wall of the flow guide to form a flange.

16. Fluidising apparatus as claimed in claim 15, in which the end wall is threaded onto the flow guide.

17. Fluidising apparatus as claimed in claim 16, in which the fluid outlet from the flow chamber is annular and is delimited on one side by the flange.

18. Fluidising apparatus as claimed in claim 16 in which the flange is movable relative to the housing of the flow chamber along the central axis of the flow chamber.

19. Fluidising apparatus as claimed in claim 15 in which the flange can be moved into abutment with a bottom edge of the housing of the flow chamber, thereby closing off the fluid outlet from the flow chamber.

20. Fluidising apparatus as claimed in claim 1 in which the portion of the flow chamber which is adjacent to the transport outlet is profiled in order to encourage a stable fluid regime between the flow chamber and the transport outlet.

21. Fluidising apparatus as claimed in claim 20, in which the said portion is generally in the shape of a cone with a concave side wall.

22. (canceled)

23. A method of removing fluidised material from a container comprising: providing a container comprising the fluidising apparatus of claim 1 where the only outlet from the container is the transport outlet, andone or more other openings which are closed during operation of the fluidising apparatus;operating the fluidising apparatus by transporting fluidised material away from the flow chamber by establishing a swirling flow passing out of the fluid outlet.

24. A fluidising apparatus comprising: a flow chamber having a fluid inlet, a fluid outlet, a housing and a substantially tubular flow guide having a side wall, the flow guide being situated at least partially within the housing, where the housing comprises a cap which fits over the flow guide;means for establishing a swirling flow in a fluid passing out of the fluid outlet comprising an opening in the side wall of the substantially tubular flow guide; anda transport outlet for transporting fluidised material away from the flow chamber, the transport outlet being situated externally of the flow chamber.

25. A container comprising: a wall; anda fluidising apparatus passing through the wall comprising: a flow chamber having a fluid inlet and a fluid outlet;means for establishing a swirling flow in a fluid passing out of the fluid outlet; anda transport outlet for transporting fluidised material away from the flow chamber, the transport outlet being situated externally of the flow chamber.