RU2224842C1 - Method of oil gathering from under ice cover in flow basin - Google Patents

Abstract

FIELD: technologies protecting environment. SUBSTANCE: invention deals with cleaning of water surface covered by ice, oil and oil products caused by breakthrough of underwater pipe-lines, disturbance of integrity of oil-containing tanks located in close proximity to water basins and by similar situations. Oil is gathered from under ice cover of water basin by its direction towards open oil receptacle with the help of barrage installed in opening of ice cover transverse to water flow, at angle with its dynamic axis with subsequent removal of oil from oil receptacle. Flexible elastic shell with weight attached to lower edge is utilized in the capacity of barrage, upper part of shell being anchored on ice cover. After installation shell is filled with water under excessive pressure. EFFECT: timely and effective localization and gathering of oil in case of breakthroughs of pipe-lines and of oil storages under conditions of water basing getting ice- bound. 1 dwg

Description

The invention relates to environmental technologies used for contamination of an ice-covered water surface with liquid hydrocarbons of oil and oil products that occur during breakthroughs of subsea oil pipelines, integrity violations of oil-containing containers located in close proximity to water bodies, and other similar situations.

A known method of collecting oil from under the ice cover using a device by AS RF №1765292, class E 02 B 15/04. Oil is collected by localizing the oil slick using an ice-covered boom that is placed under the ice through the ice hole, then pulling the oil slick to the oil receiver by towing the boom by means of a winch and pumping the oil through a hose using a pump.

A known method of collecting oil from under the ice cover of a reservoir according to the patent of the Russian Federation No. 2107127, E 02 B 15/04, including the localization of an oil polluting spot, making an ice hole in ice, placing a floating boom under an ice sheet with the formation of a closed triangular contour into which hot air is injected, and oil is collected in the lower corner of the triangular contour.

The disadvantages of these methods are as follows: their efficiency is relatively low due to the ablation of part of the oil by the flow beyond the areas marked for cleaning, the boundaries of which are limited by the fixed location of the most important working bodies of devices and ice holes, and the transfer of these boundaries is difficult due to the low mobility of the devices used. These methods are unsafe due to the need to constantly work on the surface of the ice away from the coast, including in conditions of low temperatures, wind, snowfall. In addition, the second method requires the presence of hot air, which in conditions of remoteness from habitable places and off-road in Siberia is almost unrealistic.

A known method of collecting oil from under the ice cover of a flowing body of water according to the patent of the Russian Federation No. 2176701, E 02 B 15/04, which provides for the opening of the ice cover so that the ice edge forms an acute angle with the river, and the oil accumulated in the coastal zone is sent to in advance fillers prepared on the shore.

This method is also not effective enough, because under freezing conditions at a negative air temperature, which happens in Siberia for more than 200 days a year, water in the slot begins to freeze quickly, supercooled oil, emerging, enhances water freezing and mixes with ice in the slot. As a result, there is no movement of oil (a mixture of oil and ice) to the coastal zone, and oil that has not surfaced continues to move under the ice. In the event of an oil pipeline accident, a significant release of oil occurs and even a wide (several meters) slot in ice does not save from its spread. In addition, to open the ice cover about a meter thick (the usual ice thickness in winter on Siberian rivers) and a slot width of several meters, considerable time and special equipment are required, for the delivery of which off-road conditions take time and additional funds.

The prototype of the proposed solution is a method of collecting oil from under the ice cover of a flowing reservoir, described in the article “Method for the localization and elimination of emergency oil spills at underwater crossings of oil pipelines”, published in the journal “Pipeline transport of oil” No. 11 for 1999. The method consists in that cut the ice cover across the water stream at an angle to its dynamic axis and install a barrier in it that directs oil to the coastal zone, where an oil receiver is arranged in the form of an open lane. The fence is made of separate panels of a rigid structure measuring 6x1.5 m and they are installed in the ice sheet slots with some inclination in order to block the slot. With the correct setting of the fence, the contact of oil with cold air is excluded and it moves under the ice to the oil receiver.

The known method requires less specialized equipment, it is more efficient, and the localization of the spill and the collection of spilled oil are more successful.

However, the sections of the fence are large, which leads to some complexity and the duration of transporting them to the accident site. In addition, due to the rigid structure of the barrier, it is impossible to cover all the gaps between the ice sheet and the barrier that arise due to the uneven surface of the ice sheet, as a result, part of the oil floats up and freezes in cold air.

The objective of the present invention is to provide a method of collecting oil from under the ice cover of a flowing reservoir, which would quickly and efficiently localize and collect oil in the event of an oil pipeline (oil storage) accident under ice freezing conditions.

To solve this problem, oil is collected from under the ice cover of a flowing reservoir by directing it to an open oil receiver using a barrier installed in the ice cover slot across the water flow at an angle to its dynamic axis and subsequent removal of oil from the oil receiver.

The difference from the prototype lies in the fact that a flexible elastic shell with weighting along the lower edge is used as a barrier, the upper edge of which is fixed on the ice cover, after which the said shell is filled with water under overpressure.

The drawing shows a cross section of the location of the shell in the slot ice cover: 1 - ice cover, 2 - water, 3 - oil. A flexible elastic shell was used as a barrier, for example, an inflatable boom with valves 5 for pumping water and bleeding off its excess, a skirt 6 with weighting agents 7 along the bottom edge and with devices 8 for attaching the shell to the ice cover, for example, a cable with a transverse rod, the length of which is longer the width of the slot in the ice cover 1. The weighting agent 7 may be, for example, a metal chain, which simultaneously increases the tensile strength of the shell. Discrete load can also be used. Sheath material - synthetic gas-oil-resistant material.

The method is as follows. When a pipeline breaks out or another similar situation, an oil slick spreads downstream under the ice. Downstream from the place of pollution spreading, the ice sheet is cut through the water flow at an angle to its dynamic axis. This takes into account the speed of the current and the time elapsed since the accident. For more efficient operation, it is advisable to determine the place of the fence in advance when designing the pipeline, taking into account hydrological studies of the coastline and access roads. The ice sheet can be cut through in any possible way, for example, using the BGM-1 drilling rig on a MTZ-82.1 tractor. With a small width of the river, you can use a chainsaw. The width of the slot is 0.1-0.15 m. The angle between the screen mounting barrel and the dynamic axis of the flow depends on the flow velocity. For example, the optimal angle at a flow velocity of 0.2-0.4 m / s is 30 °. In the downstream part of the slot, an oil receiver is created in the form of an open lane. A flexible elastic shell 4 is lowered into the prepared slot. With a large pond width, several sections of this shell can be used, connecting them together in the same way as the sections of an inflatable boom. The shell is suspended in the slots so that under the lower surface of the ice sheet 1 protrudes 20-30 cm of the lower part of the shell 4. The shell is pumped with a pump using water with an overpressure of 0.1 atm (0.01 MPa), which ensures almost tight closing of the working cuts at the ice-water interface and, therefore, eliminates the flow of water and oil into the ice cut and directs the oil flow along the resulting screen to the open reservoir oil collector, where the oil floats, and it can be collected with any available oil esborschikom. Uninterrupted operation of the oil collector is possible at a positive air temperature. To ensure this condition, the easiest option is to install a heated tent over an open lane. If the oil spill occurred in a pond with a small current or with still water, the water flow can be simulated using a special drag moving under the ice. As tests have shown, the installation time of one section of the fence with a team of 3 people is 5-6 minutes. To remove the shell from it with the help of a motor pump, water is pumped out, after which 1 worker removes it from under the ice. The clotting time of 1 section is 4-5 minutes. The assembled fence is compact and can be easily transported by any type of equipment.

Claims (1)

A method of collecting oil from under the ice cover of a flowing reservoir by directing it to an open oil receiver using an obstacle in the ice cover cut across the water stream at an angle to its dynamic axis, followed by removing oil from the oil receiver, characterized in that a flexible elastic shell is used as a barrier with weighting along the lower edge, the upper edge of which is fixed on the ice cover, after which the specified shell is filled with water under excess pressure.

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