GB2353230A

GB2353230A - Apparatus for the resuspension of solids in a crude oil storage tank

Info

Publication number: GB2353230A
Application number: GB0015804A
Authority: GB
Inventors: John Keith Tooley
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-07-02
Filing date: 2000-06-29
Publication date: 2001-02-21
Anticipated expiration: 2020-06-29
Also published as: GB0015804D0; GB9915491D0; GB2353230B

Abstract

The apparatus comprises a housing 2 which can be bolted at 2a to the inlet valve 10 of a manway cover 11 in the base 15 of the tank. The housing 2 has an internal bore within which a sealing piston assembly 3,4,5 is received. The piston assembly carries an S-shaped nozzle 16 which enters the tank via access opening 12 when the piston assembly is driven, by a hydraulic ram, along the housing 2 and through the valve 10. The housing 2 and piston assembly are bolted together by means of flanges 2b,4a. The nozzle is supplied with oil under pressure so that a jet of oil is discharged within the tank. The oil can be discharged in a fan-shaped pattern by pivoting the nozzle hydraulically.

Description

2353230 TOOLI 127.GF3.wpd Title - Resuspension Apparatus for Liquid

Storage Tanks This invention relates to apparatus for the resuspension of solid material in storage tanks for liquids, and in particular to an apparatus for the resuspension of accumulated sludge in crude oil storage tanks.

S Crude oil is commonly stored in massive cylindrical storage tanks. Such tanks commonly have diameters in the range 50 to 100m. Since crude oil contains suspended solid matter in the form of sludge, and since the oil may be stored in a tank for lengthy periods of time, it is common for solid material to settle out of suspension and to accumulate in the lower region of the tank. 10 It is necessary for such accumulated material to be periodically redispersed and suspended in the stored oil. Known methods of achieving this objective suffer from numerous disadvantages, not least in that they are time-consuming and hence expensive. There has now been devised apparatus for the resuspension of accumulated solids in a liquid storage tank which overcomes or substantially mitigates the above-mentioned and/or other 15 disadvantages of the prior art. According to the invention, there is provided apparatus for the resuspension of solid material in storage tanks for liquids, which apparatus comprises a housing adapted for connection to a closeable access opening in the tank, said housing having an internal bore within which a sealing piston assembly is received, said piston assembly carrying a nozzle assembly which 20 enters the tank via the access opening when said piston assembly is driven along said bore towards the tank, and means for supplying said nozzle assembly with liquid under pressure such that, in use, a jet of liquid is discharged from said nozzle assembly within the tank. The apparatus according to the invention is advantageous primarily in that it effectively breaks up, redisperses and resuspends accumulated solid material which has settled in the

TOOL] 12TGB.wpd 2 lower region of the tank. In addition, the apparatus can be quickly fitted to the tank and resuspension of the solid material can be achieved in considerably less time than has hitherto been required.

The housing is preferably a pipe or tube of sufficient internal diameter to receive the piston assembly and nozzle assembly.

The piston assembly is most preferably mounted on an inlet pipe through which oil under pressure is, in use, delivered to the nozzle assembly. The inlet pipe thus serves as a piston rod by which the piston assembly can be driven along the internal bore of the housing towards the tank.

The access opening is most preferably a manway, a number of which are conventionally provided around the lower periphery of an oil storage tank. The manway is preferably fitted with a cover which is adapted to receive the apparatus of the invention, eg by having an inlet fitted with a valve to which the apparatus can be connected and through which the nozzle assembly can be passed. The access opening is also preferably provided with an outlet, also preferably fitted with a valve, through which oil can be discharged from the tank, eg to a reservoir, and then pumped back under pressure through the nozzle assembly.

The nozzle assembly is most preferably adapted to discharge a jet of liquid under pressure close to the floor of the tank, and substantially parallel to the floor. The terminal portion of the nozzle assembly may be cranked to bring its outlet closer to the floor level, and may also be pivoted such that it can be raised whilst received within the housing and then lowered to its operational position once inside the tank- The nozzle assembly is preferably operable, either automatically or manually, such that it pivots about a vertical axis, so that the jet of liquid discharged from it traverses an angular range, typically of 90' to 150'. In this way, a substantial portion of the area of the tank is acted upon by thejet of oil. Typically, thejet may traverse from one end of the angular range TOOLI 12TGB.wpd to the other in a period of one hour or so.

The invention will now be described in greater detail, by way of example only, with reference to the accompanying drawings, in which Figure 1 is a perspective exploded view of sludge resuspension apparatus in accordance with the invention, attached at one end to an oil storage tank manway cover and at the other end to a valve; Figure 2 is a side view, partly in section, of the apparatus of Figure 1 prior to installation on an oil storage tank; Figure 3 is a side view, again partly in section, of the apparatus, in an operating condition; Figure 4 is a view on the arrow IV in Figure 3; Figure 5 is a view on the arrow V in Figure 3; and Figure 6 is a view on the arrow V1 in Figure 3.

Referring first to Figure 1, sludge resuspension apparatus according to the invention is generally designated 1. The apparatus 1 comprises a tubular housing 2 with peripheral flanges 2a,2b at its ends. The housing 2 receives a nozzle assembly 3 which is mounted on the end of an inlet pipe 4. The inlet pipe 4 carries, immediately behind the nozzle assembly 3, a cylindrical seal 5 which is dimensioned to sealingly engage the internal walls of the housing 1. A sealing flange 4a is provided near the other end of the inlet pipe 4 and is positioned and dimensioned to mate with the corresponding flange 2b at the end of the housing 2.

A hydraulic line 8 extends from the nozzle assembly 3, through the seal 5 and the flange 4a to a hydraulic cylinder 9 mounted adjacent a cranked end portion of the inlet pipe 4.

TOOL1127.GB.wpd 4 The end of the inlet pipe 4 which is remote from the housing 2 is fitted to a first inlet valve unit 7.

As shown in Figure 1, the housing 2 is connected via the flange 2a to a second inlet valve unit 10 mounted on an inlet 12 of a specially adapted manway cover I I which is also provided with an outlet 13. In practice, the outlet 13 would also be fitted with a valve (not shown). All of the mating components (eg housing 2, second inlet valve unit 10, outlet 13 and outlet valve) are provided with abutting flanges similar to the flange 2a, with angularly spaced holes by which the flanges can be sealingly bolted together in conventional fashion.

The apparatus I is fitted, in use, to an oil storage tank having manways located near the bottom thereof at intervals around the periphery of the tank. Manway covers I I are previously fitted to the manways (or at least to those of the manways to which the apparatus is to be fitted). The apparatus I is initially in the condition shown in Figure 2, in which the nozzle assembly 3 is contained entirely within the housing 2, the seal 5 closes the housing 2 behind the nozzle assembly 3, and the inlet pipe 4 projects rearwardly from the housing 2.

is Immediately prior to use, the end of the housing 2 is bolted to the second inlet valve unit 10 which is then opened. Oil from the tank can thus flow into the interior of the housing 2, surrounding the nozzle assembly 3, but is prevented from escaping from the housing 2 by the cylindrical seal 5.

The nozzle assembly 3 is then driven by a hydraulic ram (not shown) along the housing 2 and through the second inlet valve unit 10 into the tank (the wall of which is designated 15 in Figure 3), until the flange 4a abuts the flange 2b at the end of the housing 2. The flanges 4a and 2b are then bolted together. As indicated in Figure 2, the terminal portion of the nozzle assembly 3 comprises an S-shaped pipe 16 which, when the nozzle assembly 3 is housed within the housing 2, is pivoted upwards so as to reduce the overall diameter of the nozzle assembly 3 to less than the internal diameter of the housing 2. Pivoting of the S-shaped pipe 16 is brought about by the action of the hydraulic line 8. Once the nozzle assembly 3 is fully extended from the housing 2 and has passed through the second inlet valve unit 10 into the TOOLI 127.GB.wpd S interior of the tank, the S-shaped pipe 16 is pivoted into its operational position as shown in Figure 4. In this position the outlet of the pipe 16 is positioned approximately level with the lower edge of the manway, just above the floor of the tank.

An outlet pipe (not shown) is connected to the outlet valve (also not shown) connected to the S outlet 13. When the outlet valve is opened oil can flow through the outlet pipe to an external reservoir. Oil is in turn pumped under pressure from that reservoir through the first inlet valve unit 7 fitted to the cranked end portion of the inlet pipe 4 and through the inlet pipe 4 to the nozzle assembly 3.

The S-shaped pipe 16 is, during use, pivoted from side to side, again by hydraulic means, through an angular range of approximately 120'. A jet of oil under pressure is thus discharged under pressure across a fan-shaped area of the tank. The action of the liquid jet is to break up and dislodge sludge or other solid material which has accumulated in the lower region of the tank. Movement of the S-shaped pipe 16 from side to side may be under manual control, or may be automatic and continuous.

Typically, the apparatus I may be fitted in turn to each of, say, three manways spaced around the base of the tank. Alternatively, of course, several such apparatus may be fitted to a corresponding number of manways and used simultaneously. In either case, effectively the whole of the lower region o f the tank is traversed by the high pressurej et so that accumulated solids are resuspended.

Once the resuspension process has been completed, the supply of pressurised oil through the inlet pipe 4 is stopped and the first inlet valve unit 7 is closed. The outlet valve connected to the outlet 13 is also closed. The bolts holding the flanges 2b and 4a together are removed. The S-shaped pipe 16 is pivoted to its raised position and the nozzle assembly 3 is withdrawn into the housing 2. The second inlet valve unit 10 is then closed and the apparatus disconnected from that unit 10, by separation of the flange 2a from the corresponding flange of the second inlet valve unit 10.

TOOL I 127.GB.wpd 6

Claims

Claims

Apparatus for the resuspension of solid material in storage tanks for liquids, which apparatus comprises a housing adapted for connection to a closeable access opening in the tank, said housing having an internal bore within which a sealing piston assembly is received, said piston assembly carrying a nozzle assembly which enters the tank via the access opening when said piston assembly is driven along said bore towards the tank, and means for supplying said nozzle assembly with liquid under pressure such that, in use, a jet of liquid is discharged from said nozzle assembly within the tank.
2. Apparatus as claimed in Claim 1, wherein the housing is a pipe or tube of sufficient internal diameter to receive the piston assembly and nozzle assembly.
3. Apparatus as claimed in Claim I or Claim 2, wherein the piston assembly is mounted on an inlet pipe through which liquid under pressure is, in use, delivered to the nozzle assembly.
4. Apparatus as claimed in Claim 3, wherein the inlet pipe serves as a piston rod by which the piston assembly can be driven along the internal bore of the housing towards the tank.
5. Apparatus as claimed in any preceding claim, wherein a terminal portion of the nozzle assembly is cranked to bring its outlet closer, in use, to the floor.
6. Apparatus as claimed in any preceding claim, wherein a terminal portion of the nozzle assembly is pivoted such that it can be raised whilst received within the housing and then lowered to its operational position once inside the tank.
7. Apparatus as claimed in any preceding claim, wherein the nozzle assembly pivots about a vertical axis, so that thejet of liquid discharged from it traverses an angular TOOLI 12TGB.wpd 7 range of 90' to 15T.
8. A storage tank for a liquid, the tank having at its lower periphery a manway to which is connected apparatus as claimed in any preceding claim.
9. A storage tank as claimed in Claim 8, wherein the manway is fitted with a cover which receives said apparatus, by having an inlet fitted with a valve to which the apparatus is connected and through which the nozzle assembly can be passed.
10. A storage tank as claimed in Claim 9, wherein the manway is also provided with an outlet through which liquid can be discharged from the tank and then pumped back under pressure through the nozzle assembly.
11. A storage tank as claimed in any one of Claims 8 to 10, wherein the nozzle assembly of said apparatus is adapted to discharge a jet of liquid under pressure close to the floor of the tank, and substantially parallel to the floor.
12. Apparatus for the resuspension of solid material in storage tanks for liquids, substantially as hereinbefore described and as illustrated in the accompanying is Figures.