A SEPARATION APPARATUS WITH INSERT

Abstract

A separation apparatus for separating hydrocarbons and water, comprising a vessel (1) and an insert (5, 6) within said vessel (1). The has a bottom (7), a conical wall (8) and a quiecer (10) at the top of the wall (8), which enclose a separation chamber (11). The insert (5, 6) has an inlet pipe (12) for a mixture of water and hydrocarbons and a spreader arrangement (13, 14) arranged inside the separation chamber (11), which directs an inflow of fluids in a tangential direction, setting the fluids into a tangential laminar swirl. The vessel (1) has at least one manhole (3, 4), and said insert bottom (7), wall (8) and quiecer (10) are assembled by a plurality of generally wedge shaped segments (7a-l, 8a-l, 10a-l) having a size that allows the segments (7a-l, 8a-l, 10a-l) to be brought through the manhole (3, 4).

Claims

1. A separation apparatus for separating hydrocarbons and water, the separation apparatus comprising: a vessel; an insert within the vessel, the insert comprising a bottom, a generally conical wall that has a narrowing diameter from the bottom and a quiescer at the top of the wall, the bottom, wall, and quiescer enclosing a separation chamber; wherein the insert comprises an inlet pipe for an untreated mixture of water and hydrocarbons coupled to a spreader arrangement arranged inside the separation chamber immediately above the bottom, the spreader arrangement directing an inflow of fluids through the inlet pipe in a tangential direction within the separation chamber, setting the fluids into a tangential laminar swirl; and wherein the vessel has at least one manhole through which a person can get access to the inside of the vessel, and the insert bottom, wall and quiescer are assembled by a plurality of generally wedge shaped segments, the segments having a size that allows the segments to be brought one by one through the manhole.

2. The separation apparatus of claim 1, wherein the inlet pipe is adapted to support the weight of the insert, the inlet pipe having a first and a second bolt ring attached thereto at mutual distance, the segments of the bottom being adapted to be bolted to the first bolt ring and the segments of the quiescer being adapted to be attached to the second bolt ring.

3. The separation apparatus of claim 2, wherein the inlet pipe extends from above the insert, through the quiescer to the spreader arrangement, and that both the two bolt rings are attached directly to the pipe.

4. The separation apparatus of claim 2, wherein the inlet pipe extends from below the insert, through the bottom, and that a first bolt ring is attached directly to the pipe and a second bolt ring is attached to a rod that in turn is attached to an end of the inlet pipe.

5. The separation apparatus of claim 1, wherein each segment has a web part at the edges that are to be attached to adjoining segments, the web part extending at right angle to a main plane of the segment, the web part 17 facing away from the separation chamber, web parts of adjoining segments being adapted to be connected by bolts.

6. The separation apparatus of claim 1, wherein the quiescer segments comprises a grating along their main plane.

7. The separation apparatus of claim 1, wherein the bottom, the wall and the quiescer have the same number of segments.

8. The separation apparatus of claim 1, wherein the segments constituting the bottom, wall and quiescer, respectively, are identical.

9. The separation apparatus of claim 1, wherein the vessel is a gravity separator and that the fluids exiting from the insert through the quiescer are further separated by gravity separation in the vessel outside of the insert.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0020] The invention will now be explained in further detail, referring to exemplary embodiments shown in the accompanying drawings, in which: FIGS. 1-4 show a gravity separator vessel with two inserts according to the present invention in partially transparent views, where:

[0021] FIG. 1 shows the vessel in an isometric view,

[0022] FIG. 2 shows the vessel in a side elevation view,

[0023] FIG. 3 shows the vessel in a planar top view, and

[0024] FIG. 4 shows the vessel in end elevation view.

[0025] FIGS. 5-8 show an insert according to the invention in various views, where:

[0026] FIG. 5 shows the insert in isometric view,

[0027] FIG. 6 shows the insert in cross-sectional elevation view,

[0028] FIG. 7 shows the insert in a top planar view, and

[0029] FIG. 8 shows a top cross-sectional view.

[0030] FIG. 9 shows a partially assembled insert in a first embodiment, and

[0031] FIG. 10 shows a partially assembled insert in a second embodiment.

DETAILED DESCRIPTION OF THE INVENTION

[0032] FIG. 1 shows a gravity separator vessel 1. The vessel is generally cylindrical. It has an inlet tube for well fluid and outlet tubes for water and oil and possibly gas. These are not shown in FIGS. 1-4. In the vessel, water and oil will separate due to gravity. In the vessel 1 a light liquid bucket 2 is arranged at a level which allows the oil to flow into the bucket 2.

[0033] The vessel has manholes 3, 4 for inspection of the interior of the vessel 1. These manholes 3, 4 are large enough for a person to crawl through.

[0034] FIGS. 1-4 shows two inserts 5, 6 that have been arranged within the vessel. The inserts 5, 6 are according to the invention and will be explained in detail below.

[0035] FIGS. 5-8 shows one insert 5 of the invention. The insert 5 comprises a bottom 7 (best shown in FIG. 6). The bottom has a slightly conical or convex shape with its lowest point along the perimeter of the bottom 7. The bottom is made up of a plurality of wedge-shaped segments 7a-7l (in the present case twelve segments), which are assembled to form a circular bottom.

[0036] The insert also has a wall 8, which joins the bottom 7 at the perimeter thereof. The wall 8 is generally conical, but may, as shown have a small cylindrical part 9 close to the bottom 7. The wall 8 is also made up of wedge-shaped segments 8a-8l (twelve in the shown embodiment).

[0037] At the top of the wall 8 a quiescer in the form of a grating 10 is attached. The grating 10 is also made up of wedge-shaped segments 10a-10l (twelve in the present case) that assembled form a circle.

[0038] The bottom 7, wall 8 and grating 10 enclose a separation chamber 11.

[0039] An inlet pipe 12 extends through the middle of the separation chamber 11 to the bottom 8 and is preferably attached to the apex of the bottom 8. The upper end of the pipe 12 extends out through the wall of the vessel 1. From the inlet pipe 12 a plurality of spreader arms 13 extend radially towards the wall 8. The spreader arms 13 have an outer portion 14 that extends in a tangential direction along the wall 8.

[0040] At the inside of the upper part of the wall 8 vertical vanes are arranged (not shown in the drawings).

[0041] The function of the separator insert is described in detail in NO 20190982 and will therefore only be given briefly here:

[0042] Well fluids mixed with gas are flowing through the pipe 12 to the spreader arms 13. Die to the tangential direction of the outlet from the spreader arms 13, the well fluid will be set into a swirling motion. The swirling motion will increase as the fluids are forced upward within the conical chamber 11. Particles in the fluids will be flung outwards and fall towards the bottom 7 along the wall 8 and collect at the perimeter of the bottom 7. Water in the swirling fluids will tend to collect into larger droplets, and as the flow exits the chamber 11 at the grating 10, the water will flow downwards on the outside of the insert 5 while the lighter oil and gas will collect above the insert 5.

[0043] The vanes (not shown) will slow down the swirl before it exits the insert 5, and the grating 10 at the top of the insert 5 will force the flow into an outwardly directed radial laminar flow.

[0044] Consequently, when the fluids exit the chamber 11 the water will already have been separated to a large extend from the oil and gas. The vessel 1 outside of the insert 5 will function as a gravitational separator and allow the fluids to further separate due to gravity. Hence the retention time of the fluids in the vessel can be greatly reduced compared to a conventional gravity separator.

[0045] It is convenient if the number of wedge-shaped segments of the bottom 7, wall 8 and grating 10 is equal, but it is also feasible to have a different number of segments for the bottom, wall and grating.

[0046] FIG. 9 shows a partially assembled insert. In this case the inlet pipe 12 enters the vessel 1 through the top thereof. The pipe 12 is equipped with a first bolt ring 15 and a second bolt ring 16. The bolt rings 15, 16 are preferably welded to the outside of the pipe 12. The first bolts ring 15 serves to support the bottom segments 7a-7l and the second bolt ring 16 serves to support the grating segments 10a-10l. In FIG. 9 one segment for each of the bottom 7, wall 8 and grating 10 has been mounted. These are denoted 7a, 8a and 10a.

[0047] Each of the segments 7a, 8a and 10a comprises a main portion A. For the bottom segment 7a and the grating segment 8a, this portion is generally planar, but for the wall segment 8a, the main portion is divided into a conus section A1 (i.e. a part of the resulting conical wall 8, and a cylinder section A2.

[0048] At right angle to the main portions are formed webs 17. These webs 17 are adapted to be mated with corresponding webs of adjoining segments. When the webs 17 of two adjoining segments are mated, a sealing is placed between the two webs. This can be a rubber seal, a polyurethane seal or similar sealing material that will endure the temperature and chemical impacts by the fluids in the separator.

[0049] With the seal in place, the webs are fixedly attached to one-another by bolts inserted through the webs.

[0050] While FIG. 9 shows an insert where the inlet pipe 12 extends through the upper part of the vessel 1, FIG. 10 shows an embodiment with the inlet pipe 12 extending through the lower part of the vessel 1. This embodiment deviates from the embodiment of FIG. 9 by not having a second bolt ring 16 placed around the pipe 12. Instead the second bolt ring is placed at the end of a rod 18, that extends upwards from a closed end of the pipe 12. A grating 19 is arranged within the bolt ring 16. This grating 19 is of the same type as the grating 10. The two bolt rings 15, 16 are held at the same distance as the bolt rings 15, 16 of FIG. 9.

[0051] The installation of the insert may be done in a varying sequence depending on the space available within the vessel. Now will be explained a few alternative sequences.

[0052] First an opening 20 (see FIG. 1) for the inlet pipe 12 is made either at the top or the bottom of the vessel, depending on which direction the inlet is planned to be entering the vessel. The chosen direction depends on the space available above and below the vessel and where the well flow ducts are in relation to the vessel.

[0053] The pipe 12 is strong enough to carry the weight of the insert. Hence, the pipe 12 will be fixedly attached to the vessel wall. This may be done by welding or by attaching a collar to the vessel and around the pipe 12 at the opening 20.

[0054] The pipe may be brought through one of the manholes 3, 4 and inserted through the opening 20 from the inside of the vessel 1. Next the pipe 12 is positioned at a predetermined distance from the bottom of the vessel 1, which provides the workers sufficient space for performing the assembly of the insert.

[0055] When the pipe 12 has been positioned and fixedly attached to the vessel 1, the assembly of the segments forming the bottom 7, wall 8 and grating 10 can commence. The sequence of this assembly depends on the space available and the size of the insert.

[0056] In one sequence, the segments 7a-7l of the bottom 7 are first assembled by bolting the segments one by one to the first bolt ring 15 and to the adjoining segments. Then the spreader arms 13 are attached to the pipe 12 via flange connections. Then the wall segments 8a-8l are attached by bolts to the perimeter of the bottom 7 and to the adjoining wall segments. Finally, the grating segments 10a-10l are attached to the second bolt ring 16, to the top of the wall 8 and to the adjoining grating segments.

[0057] However, the assembly may also be done by attaching one bottom segment 7a, one wall segment 8a and one grating segment 10a to each other and then attach the combined structure to the bolt rings 15, 16. FIGS. 9 and 10 show the situation when the first combined structure has been attached. In this case, the spreader arms 13 will have to be attached to the pipe 12 either before the first segments 7a, 8a, 10a are attached, or at least before the last segments 7l, 8l, 10l are attached.

[0058] The bolt rings 15, 16 preferably have threaded holes, which enables the bolts to be screwed in from the outside of the insert without the need for a nut on the inside. The webs may be bolted together by bolts and nuts, as these are readily accessible from the outside of the insert.

[0059] When all the segments of the bottom 7, wall 8 and grating 10 have been assembled and are supported by the pipe 12, struts (not shown) are attached to the insert, at separate brackets (not shown) or a web 17, and already present features inside the vessel 1, such as the liquid bucket 2, partition walls or similar. These struts serve to stabilize the insert and prevent it from oscillating due to the swirling fluids. The positioning and length of the struts depend on the construction of the individual vessel 1.

[0060] Especially in larger vessels, the inlet pipe may also be fed through the vessel wall from the side or through the end caps, and the inlet pipe may have a bend that turns the direction of the pipe into the vertical. In that case the pipe has to be supported by brackets inside the vessel.

[0061] With the insert, or inserts properly installed inside the vessel, all that remain is to connect the inlet pipe to the well flow and gas mixer and close the manholes. The insert will separate the water and hydrocarbons efficiently. After this separation, the gravity separation inside the vessel but outside the inserts will work at a much higher efficiency than the original gravity separation without the inserts.