RU2723799C1 - "dome" type device for liquidation of underwater oil spills complete with process equipment - Google Patents

Abstract

FIELD: environmental protection.SUBSTANCE: invention relates to environmental protection in terms of maintaining water bodies in proper condition and is intended for liquidation of emergency oil spill by localization of underwater spill and redirecting oil flow to surface with possibility of further transportation or recycling. Device "dome" represents metal structure with reservoir of cylinder shape opened from below, smoothly changing into dome-shaped upper part. Structure contains a power frame of round cross-section pipes closed on a flat base. Flange of quick-detachable connection is welded on base in lower part of structure. Dome has a reservoir inside an open in the lower part of the case. On the structure there fixed is a metal cavity of the heat exchanger, which is located inside the housing for circulation of heat carrier, device for fixation of cable-rope sealing, buoyancy units for provision of positive buoyancy, electric winches of deep-water execution for performance of "dome" movements during positioning and pointing operations, sensors of the medium control system, strong housing with installed inside components of control system and unit of electric power elements.EFFECT: increased efficiency of oil pumping out due to heating of oil mixture.7 cl, 1 dwg

Description

The invention relates to the field of environmental protection in terms of maintaining water bodies in good condition and is intended to eliminate an emergency oil spill by localizing an underwater spill and redirecting the oil flow to the surface for subsequent transportation or disposal.

A known system for collecting and localizing oil in an aqueous medium in the form of a dome in the form of a truncated pyramid having 4, 5 or 6 faces, in the center of the pyramid there is a round hole to which a sleeve formed from separate panels fastened with fastening devices is attached via a connecting ring, connected to the sleeve by means of connecting rings, and held upright by floats attached to the connecting rings. RU No. 2634118 C1, publ. 10.24.2017.

The system is fixed above the spill site by means of anchor ropes attached to dead anchors installed at the bottom. A boom is installed on the surface of the water around the upper edge of the sleeve, which is anchored to dead anchors at the bottom by anchor ropes and holds the upper edge of the sleeve in the center of the fence by stretch marks.

In this case, the upper edge does not reach the surface of the water and allows oil or oil products to freely exit and spread over the surface of the water area, limited by the boom. The prototype has the following disadvantages:

- the dome and connecting sleeve in the unfolded state are dimensional, which makes it doubtful whether the system can be deployed and installed in a predetermined position in deep waters;

- the presence of many bonds and stretch marks under adverse weather conditions can lead to their confusion;

- there are no methods to combat the formation of hydrates and deposits.

The technical result of this invention is the creation of a system that eliminates the above disadvantages and ensures the conduct of emergency response operations on any source of oil leakage at depths of up to 2200 m, with the possibility of ships operating at a safe distance from the source of the spill.

The dome device is a metal structure with a cylindrical reservoir open from the bottom, smoothly turning into a domed upper part. The design is based on a power frame made of circular pipes, closed to a flat base.

The tank body has a metal cavity located on the inner surface and is a heat exchanger for circulating the coolant and heating the flooded oil mixture. The housing has an opening with a connecting device for docking the transportation pipeline. On the heat-insulated outer surface of the housing there are openings for the coolant to exit (since the heating system is open). A quick-connect flange is welded to the flat base of the structure. The counter flange is mounted on a reinforced concrete structure that acts as a ballast during immersion and the role of an anchor during operation.

A device is mounted to the upper frame elements for connection with a power termination of a cable cable.

Spherical-plastic buoyancy blocks are attached to the frame structure on the outer surface of the body, which are necessary to ensure positive buoyancy of the structure without ballast and give a streamlined shape to the upper part of the device.

Four electric winches of deep-water design are installed along the perimeter of the base equidistant from each other on the lower part of the frame. Winches are designed to change the length of anchor ties to ensure the implementation of horizontal and vertical movements of the "dome" during the operations of positioning and pointing to a point.

The sensors of the environmental control system (depth, temperature sensor, oil product analyzers, sonar sensors for detecting associated gases) are located symmetrically around the circumference of the cross section of the tank body of the “domed” space that localizes the oil flow.

The hardware of the systems is located in an airtight, durable case with the volume necessary for placement inside the components of the block of electric power elements. The robust housing has pressure glands for connecting power and control cables.

The materials used in the design of the device are resistant to prolonged exposure to aggressive environments, such as sea water with a high content of hydrogen sulfide.

The functioning of the device is ensured by the installation of the following connections:

- electrical and power communication with a surface vessel by means of a cable-rope for hoisting operations, transmission of electricity, information and control signals (via a fiber optic channel);

-transportation hydraulic connection with a surface vessel in the form of a specialized flexible pipeline for pumping oil from the "dome" and transferring the coolant;

- sonar communication with a vessel or TYPE for navigational support of the “dome” operation through sonar transponder beacons and sonar;

-power ties with anchors located at the bottom, for fixing the "dome" in a given position and adjusting it if necessary.

A set of "domes" incorporates the following process equipment:

- anchors with beacons responders;

- hoisting device (SPU) with cable;

- a flexible specialized pipeline with a pump for transporting oil;

- a container with shipboard control equipment;

- power supply container;

- container with ship rigging;

- a container with spare tools and accessories (spare parts);

- a complex of remote-controlled uninhabited underwater vehicle (TYPE).

A set of technological equipment together with the “dome” is mobile, stored at the coastal base and transported to the accident area on a carrier vessel.

The principle of operation of the device is based on blocking the oil flow from the leak through adaptive positioning (the ability to change position when changing the parameters of the pumped medium), followed by transportation of the oil mixture to the surface (vessel) through the pipeline using a specialized submersible pump.

The main advantage of the “dome” is the possibility of installing it from the surface of the water above any source of oil leakage (wellhead equipment of subsea wells, emergency riser, elements of the subsea production complex, subsea pipeline, bottom cracks with the formation of griffins, etc.) at depths up to 2200 m At the same time, it is significant that the vessels participating in the accident liquidation operation can operate at a safe distance from the source of the spill (without entering the oil slick zone).

The main difficulty lies in the method of ensuring operability and sufficient pumping efficiency. Under conditions of relatively low temperatures and high pressure at great depths of the sea in the “dome” space and the transportation pipeline, when light hydrocarbons or gas molecules come into contact with water, the formation of gas hydrates in the form of crystalline deposits is inevitable, which in turn leads to a narrowing and complete blockage flow section of the pipeline.

In world practice, this phenomenon was encountered during attempts to install an identical device for the purpose of oil spill response in the Gulf of Mexico in 2010. In this case, the attempts were unsuccessful. The massive steel “dome” turned out to be inoperative as a result of the ill-conceived method of combating gas hydrates.

In addition, at low temperatures, oil viscosity increases and the likelihood of formation of paraffin deposits appears, which also leads to blockage of the flow area.

In practice, when transporting oil, to prevent the formation of deposits and increase the fluidity of the oil mixture, the method of heating the mixture has proven itself.

In the proposed device, the heating is carried out by transferring heat through the heat exchanger of the "domed" space by supplying hot water along the external circuit of the transportation pipeline. The flexible transportation pipeline of the “dome” is a heat-insulated system of the “pipe in pipe” type.

An external open circuit between the heat-insulated pipes of the transport pipeline delivers hot water from the boilers of the carrier vessel down to the heat exchanger of the “domed” space. The dimensions of the “dome” heat exchanger and the flow diameters of the external and internal pipelines are selected so that the surface of the heat exchanger can provide heating, and the internal pipeline is followed by transportation of the oil mixture in the amount of up to 475 m ³ / h.

An alternative method of combating gas hydrates is the electric heating method. However, its use at great depths is technically difficult for the following reasons:

- increases the hydrodynamic resistance to movement of the electrical connection due to the increase in its diameter as a result of the use of a massive heating cable with conductive conductors of large cross section for transmission of high power and, accordingly, due to the installation of additional buoyancy units for unloading;

- there is no sufficient flexibility of the heating cable (increase in connection stiffness), which is a significant factor when the carrier vessel performs operations at a safe distance from the leak source;

- there is a need to install additional electrical converters in underwater design with significant weight and size characteristics.

In FIG. shows a schematic diagram of the kit "dome". After examining the current underwater situation in the accident zone using TNLA 1 and determining the optimal positioning scheme, three anchors 3 with transponder beacons are installed at the bottom in a certain range along the radius from leak point 2. Then from the carrier vessel 4 using SPU 5 on the cable cable 6 descends the "dome" 7.

Structurally, the device "dome" has a positive buoyancy. In the initial position, for the descent operation, the negative buoyancy of the device is ensured by fastening the ballast anchor 9 with the help of the quick disconnect device 8. After the device is lowered, the ballast anchor is automatically or automatically, if necessary, TYPE (if necessary).

The “dome” floats to a predetermined height and remains connected to the anchor by means of a synthetic cable 10, the length of which is adjusted by one of the winchs installed on the “dome” 11. The “dome” itself and each anchor are equipped with a responder beacon 12 to ensure accurate observation during positioning and adjusting the position during the descent and installation in the working position.

The defendant beacon is anchored in buoy 13, which has positive buoyancy, and in the underwater position rises above the anchor on a synthetic cable with a length of about 20 m, which ensures its visibility when the anchor is buried in the silt. TYPE, using a manipulator complex, engages the free end of the cable of each of the "dome" winches with the anchor cable bracket.

The holding force of each anchor and the synthetic winch cable are designed to hold the underwater position of the “dome” under the force of the fountain of the leaking fluid and increase positive buoyancy by filling the “dome” space with gas hydrates.

After the “dome” is unfastened with anchor links, the operator, located on the carrier vessel, using the remote control system for winches, directs the “dome” in an area suitable for connecting the transportation pipeline.

Next, the transportation pipeline 14 is launched with unloading in the form of buoyancy units and its further connection to the device using TYPE means. After that, the operation is carried out to bring the “dome” into the working area above the leak source. Thanks to anchor connections, with horizontal guidance into the working area, the device remains stable even at high oil flow pressure and unstable flow.

An environmental control system 15 is installed on the “dome”, according to the information signal of which, together with the data from the TNPA cameras, the operator guides or corrects the position of the device by the method of successive approximation to localize the maximum volume of oil. When the optimal working area is determined, and further adjustment is not required, the transportation system and the mixture are heated.

The “Dome” can be used in the working position for a long period of time (up to 3 months) until measures are taken to eliminate the leak. The device is reusable.

Claims (7)

1. The device is a type of "dome" for the elimination of underwater oil spills complete with technological equipment, consisting of a device in the form of a metal structure with an open bottom housing of the tank of complex shape, and elements of the kit that provide functioning, characterized in that the device is made in the form of a metal frame structures made of pipes of circular cross-section, closed on a flat base and having a tank open inside the lower part of the casing, while the metal cavity of the heat exchanger located inside the casing for circulating the coolant, a quick disconnect flange welded to the base in the lower part, are fixed to the structure cable cable termination, buoyancy units to ensure positive buoyancy, deep-sea electric winches to perform dome movements during positioning and pointing operations, sensors of the environmental control system, rugged housing with inside the control system components and the block of electric power elements. 2. A device of the "dome" type for the elimination of underwater oil spills according to claim 1, characterized in that the device is operated in conjunction with a set of technological equipment, which includes anchors with beacon responders, a hoisting device with a cable cable, a flexible specialized pipeline with a pump for transporting oil, a container control system and energy supply; a container with ship rigging, a container with spare tools and accessories, a complex of remote-controlled uninhabited underwater vehicle. 3. A device of the “dome” type for the elimination of underwater oil spills according to claim 1, characterized in that the set of technological equipment included in the device is mobile and reusable, and its storage is carried out on the coastal base. 4. A device of the "dome" type for the elimination of underwater oil spills according to claim 1, characterized in that the deployment of the system can be carried out from the surface of the water outside the zone of the oil slick to a depth of 2200 m above any source of leakage. 5. The device type "dome" for the elimination of underwater oil spills according to claim 1, characterized in that the device provides a system for combating the formation of gas hydrates and viscous deposits, which is a system for heating the oil mixture by supplying hot water through a "domed" heat exchanger space, followed by maintaining the temperature of the mixture along the pipeline, provides transportation and heating of the oil mixture. 6. A device of the "dome" type for the elimination of underwater oil spills according to claim 1, characterized in that the device provides a positioning and position adjustment system using remotely controlled electric winches by changing the length of the anchor link cables with anchors installed at the bottom. 7. A device of the "dome" type for the elimination of underwater oil spills according to claim 1, characterized in that the device is equipped with an adaptive control system with feedback that is sensitive to changes in flow parameters and flow direction.

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