GB2074887A

GB2074887A - Oil recovery apparatus and method

Info

Publication number: GB2074887A
Application number: GB8112776A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-05-02
Filing date: 1981-04-24
Publication date: 1981-11-11
Also published as: GB2074887B

Abstract

Oil floating on the sea is recovered by trawling a net 10 having a tubular dracone 15 at the trailing end through the oil to collect the oil in the dracone. The oil may be heavy crude in which case the mesh size of the dracone is sufficiently small to contain the collected oil, but if the oil is a light oil, the method may require an initial step of causing the oil to solidify by applying a solidifying agent, which may be a chemical or absorbent chips, to the oil slick. <IMAGE>

Description

SPECIFICATION Oil recovery apparatus and method This invention relates to apparatus for and a method of oil recovery at sea.

According to one aspect of the present invention there is provided a method of recovering oil from an oil slick at sea comprising the steps of a net having a tubular dracone at the trailing end through the oil slick and collecting the oil in the dracone.

The oil may be heavy crude in which case the mesh size of the dracone is sufficiently small to contain the collected oil.

If the oil is a light oil the method may require an initial step of causing the oil to solidify by applying a solidifying agent to the slick. The solidifying agent may be a chemical or an absorbent chip.

Preferably, the method includes the step of detaching the filled dracone from the forenet and replacing it by an empty dracone.

Preferably also, the method includes pumping the light oil contained in the dracone into a tank and separating the oil from the solidifying agent.

According to another apsect of the present invention, there is provided apparatus for use in recovering oil from an oil slick at sea, comprising a tubular trawl net having a leading open end which tapers to an elongate narrow tubular net or dracone at the trailing end for collection of oil therein.

Preferably, the trawl net comprises a forenet which has a relatively large open leading end, tapering side wall or walls which form a relatively small opening at the trailing end and a tubualr rear extension therefrom, and a tubular dracone detachably secured to the rear extension of the forenet.

Preferably also, a dracone coupler is provided, part of which is attached to the leading end of the dracone and part of which is attached to the trailing end of the forenet rear extension.

Preferably also, a boom is provided to support the leading end of the forenet and locate the net alongside the hull of a vessel.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings in which: Fig. 1 is a plan view illustrating the apparatus alongside a vessel; Fig. 2 is a front elevation of the apparatus to a larger scale.

Fig. 3 is a detail showing part of the apparatus after use; and Fig. 4 is a detail of the apparatus.

Referring to the drawings, the apparatus comprises a tubular trawl net 10, the leading end of which is suspended from the boom 11 extending out from the side of an oil recovery vessel 12.

The net is in two parts namely, a forenet 14 and a dracone 15, which is detachably secured as illustrated in Fig. 4 to the rear end of the forenet.

The forenet 14 may be conical or other suitable section, but in this embodiment, it has a trapezoidal section as illustrated in Fig. 2, the leading end tapering to a small rectangular rear opening 1 6 from which a rear extension piece 1 7 extends. A dracone coupler 20 is provided, one part being attached to the extension piece 1 7 and the other part being attached to the leading end of the dracone 1 5. The dracone 1 5 is a narrow elongate net closed at its rear trailing end.

Choker lines 21, 22 are provided, one at the leading end of the dracone, one at the trailing end.

The trawl is made entirely of nylon twine. The forenet to the dracone coupler is 1 4 mm. mesh; the dracone 7 mm. mesh. The net is roped to 10 mm. polypropylene rope, with 12 mm.

polyester rope securing the net to the ship's side and supporting the main weight.

The outside wing or upright 25 of the net is longer (x 2) than the inside wing to ensure good water/net contact in heavy weather.

The trawl is deployed as shown and the vessel proceeds through the oil slick. When the dracone is full the leading choker is tightened and the dracone uncoupled. This can be buoyed and left for uplift or towed behind the vessel. Another dracone can be deployed and the tow continued.

By tightening the trailing choker approximately 500 kilos of oil can be recovered at a time.

The net is designed primarily for the collection of heavy crude oil, and the narrative describes the process required for such oils. The process can, however, be adapted for use in relation to light oils. Such light oil slicks are treated either by chemicals or absorbent chips which solidify the oil. The oil collected in the dracone is pumped on board by means of a 14" submersible pump connected to the after end of the dracone. The oil can then be separated from the chips and the chips re-cycled for further use.

Various mesh sizes can be used for the forenet and dracone depending on the type of oil to be cleared.

Although the drawings show the trawl net on one side of the vessel only, it would be intended to practice that nets be attached to each side of the vessel.

1. A method of recovering oil from an oil slick at sea comprising the steps of trawling a net having a tubular dracone at the trailing end through the oil slick and collecting the oil in a dracone.

2. A method as claimed in claim 1, wherein, if oil is heavy crude the mesh size of the dracone is sufficiently small to contain the collected oil.

3. A method as claimed in claim 1 , wherein, if the oil is a light oil there is an initial step of causing the oil to solidify by applying a solidifying agent to the slick.

4. A method as claimed in any one of claims 1 to 3, including the step of detaching the filled dracone from the forenet and replacing it by an empty dracone.

5. A method as claimed in claim 3 including the step of pumping the light oil contained in the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Oil recovery apparatus and method This invention relates to apparatus for and a method of oil recovery at sea. According to one aspect of the present invention there is provided a method of recovering oil from an oil slick at sea comprising the steps of a net having a tubular dracone at the trailing end through the oil slick and collecting the oil in the dracone. The oil may be heavy crude in which case the mesh size of the dracone is sufficiently small to contain the collected oil. If the oil is a light oil the method may require an initial step of causing the oil to solidify by applying a solidifying agent to the slick. The solidifying agent may be a chemical or an absorbent chip. Preferably, the method includes the step of detaching the filled dracone from the forenet and replacing it by an empty dracone. Preferably also, the method includes pumping the light oil contained in the dracone into a tank and separating the oil from the solidifying agent. According to another apsect of the present invention, there is provided apparatus for use in recovering oil from an oil slick at sea, comprising a tubular trawl net having a leading open end which tapers to an elongate narrow tubular net or dracone at the trailing end for collection of oil therein. Preferably, the trawl net comprises a forenet which has a relatively large open leading end, tapering side wall or walls which form a relatively small opening at the trailing end and a tubualr rear extension therefrom, and a tubular dracone detachably secured to the rear extension of the forenet. Preferably also, a dracone coupler is provided, part of which is attached to the leading end of the dracone and part of which is attached to the trailing end of the forenet rear extension. Preferably also, a boom is provided to support the leading end of the forenet and locate the net alongside the hull of a vessel. An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings in which: Fig. 1 is a plan view illustrating the apparatus alongside a vessel; Fig. 2 is a front elevation of the apparatus to a larger scale. Fig. 3 is a detail showing part of the apparatus after use; and Fig. 4 is a detail of the apparatus. Referring to the drawings, the apparatus comprises a tubular trawl net 10, the leading end of which is suspended from the boom 11 extending out from the side of an oil recovery vessel 12. The net is in two parts namely, a forenet 14 and a dracone 15, which is detachably secured as illustrated in Fig. 4 to the rear end of the forenet. The forenet 14 may be conical or other suitable section, but in this embodiment, it has a trapezoidal section as illustrated in Fig. 2, the leading end tapering to a small rectangular rear opening 1 6 from which a rear extension piece 1 7 extends. A dracone coupler 20 is provided, one part being attached to the extension piece 1 7 and the other part being attached to the leading end of the dracone 1 5. The dracone 1 5 is a narrow elongate net closed at its rear trailing end. Choker lines 21, 22 are provided, one at the leading end of the dracone, one at the trailing end. The trawl is made entirely of nylon twine. The forenet to the dracone coupler is 1 4 mm. mesh; the dracone 7 mm. mesh. The net is roped to 10 mm. polypropylene rope, with 12 mm. polyester rope securing the net to the ship's side and supporting the main weight. The outside wing or upright 25 of the net is longer (x 2) than the inside wing to ensure good water/net contact in heavy weather. The trawl is deployed as shown and the vessel proceeds through the oil slick. When the dracone is full the leading choker is tightened and the dracone uncoupled. This can be buoyed and left for uplift or towed behind the vessel. Another dracone can be deployed and the tow continued. By tightening the trailing choker approximately 500 kilos of oil can be recovered at a time. The net is designed primarily for the collection of heavy crude oil, and the narrative describes the process required for such oils. The process can, however, be adapted for use in relation to light oils. Such light oil slicks are treated either by chemicals or absorbent chips which solidify the oil. The oil collected in the dracone is pumped on board by means of a 14" submersible pump connected to the after end of the dracone. The oil can then be separated from the chips and the chips re-cycled for further use. Various mesh sizes can be used for the forenet and dracone depending on the type of oil to be cleared. Although the drawings show the trawl net on one side of the vessel only, it would be intended to practice that nets be attached to each side of the vessel. CLAIMS

5. A method as claimed in claim 3 including the step of pumping the light oil contained in the dracone into a tank and separating the oil from the solidifying agent.

6. Apparatus for use in recovering oil from an oil slick at sea, comprising a tubular trawl net having a leading open end which tapers to an elongate narrow tubular net or dracone at the trailing end for collection of oil therein.

7. Apparatus as claimed in claim 6, in which the trawl net comprises a forenet which has a relatively large open leading end, tapering side wall or walls which form a relatively small opening at the trailing end and a tubular rear extension therefrom, and a tubular dracone detachably secured to the rear extension of the forenet.

8. Apparatus as claimed in claim 6 or 7, in which a dracone coupler is provided, part of which is attached to the leading end of the dracone and part of which is attached to the trailing end of the forenet rear extension.

9. Apparatus as claimed in claim 7 or 8, in which a boom is provided to support the leading end of the forenet and locate the net alongside the hull of a vessel.

10. A method of recovering oil from an oil slick at sea substantially as hereinbefore described.

11. Apparatus for use in recovering oil from an oil slick at sea, substantially as hereinbefore described with reference to the accompanying drawings.