Method and a system for removal of oil under ice

Abstract

Provided is a method and a system for removal of oil under ice through an opening made into ice. The system includes oil booms extending under ice in two different directions from the opening so as to constitute an angle of less than 180 degrees between each other; an oil collection device placed in the opening; and a propulsion device placed on the level of the lower surface of ice at a distance from the opening in the area of the angle so as to provide a flow directed towards the opening between the oil booms in the area of the angle.

Claims

1. A method for removal of oil under ice through an opening made into ice, wherein an opening is made into ice, two oil booms able to be pressed against the lower surface of ice are provided under ice so as to extend in different directions from the opening, jointly constituting an angle of less than 180 degrees, an oil collection device is provided in the opening and a flow directed towards the opening is provided by introducing a propulsion device under ice from a second opening made into ice on the lower surface of ice in the area of said angle so as to transfer the oil on the lower surface of ice towards the opening and the oil collection device by the guidance of the booms to recover the oil, wherein the propulsion device includes a rotatable propeller configured to be placed under ice through the second opening made into ice, and wherein the two oil booms are positioned at a distance from the oil collection device, and the second opening is positioned at at least the same distance from the oil collection device as the two oil booms and within the angle between the two oil booms.

2. A system for removal of oil under ice through an opening made into ice, wherein the system includes oil booms configured to extend under ice in two different directions from said opening so as to constitute an angle of less than 180 degrees between each other; an oil collection device configured to be placed in the opening; and a propulsion device configured to be placed on the level of the lower surface of ice at a distance from the opening in the area of said angle so as to provide a flow directed towards the opening between the oil booms in the area of the angle, wherein the propulsion device includes a rotatable propeller configured to be placed under ice through a second opening made into ice, and wherein the two oil booms are positioned at a distance from the oil collection device, and the second opening is positioned at at least the same distance from the oil collection device as the two oil booms and within the angle between the two oil booms.

3. The system according to claim 2, wherein the system includes at least two propulsion devices placed in the area of said angle at a distance from each other.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The accompanying drawing, which is included to provide a further understanding of the invention and constitutes a part of this specification, illustrates schematically an embodiment of the invention and together with the description helps to explain the principles of the invention.

DETAILED DESCRIPTION

(2) In the system and the method according to the FIGURE, when oil is present under ice and should be removed, an opening 1 is first made into ice. Two oil booms 2 are conveyed under ice through the opening 1 in such a way as to extend from this opening 1 and project in different directions in such a way that they constitute an angle 3 between each other. The angle must be smaller than 180 degrees. Most appropriately, it is of the order of 90 degrees, possibly 50-100 degrees, depending on the extent of the area being cleaned and the length of the oil booms being used.

(3) A good way of opening the oil booms straight under ice is first to float ropes in two directions from the opening 1 and pull them up at a sufficient distance from small openings 8. The applicable floating devices are common for example among fishermen engaging in net fishing in winter. Finally, the ropes can be used to pull the oil booms in place and at an angle relative to each other and lock them in place between the opening 1 and the small openings 8.

(4) Next, an oil collection device 4 that may be a skimmer based on the rotating brush technique or any other device appropriate for separation and recovery of oil is installed in the opening 1.

(5) Then, at least one further opening 7 is made in the area of the open angle 3, for example approximately between the ends of the oil booms or even farther. A propulsion device 6 is placed in this opening 7. It may be an outboard motor used in boats, a water or air pump or other device for providing a flow in the desired direction under ice. It should be noted that the flow need not be very strong. Under ice, the conditions are in general quite steady, so that even a small extra flow will make the layer of oil move in the desired direction.

(6) Thus, in the method and the system according to the invention the oil collection device 4 at the vertex of the angle 3 recovers oil flowing into the opening 1, generating slight suction at the angle. At the same time, the propulsion devices 6 push oil towards the vertex of the angle 3 by an under-ice flow 5. Thus, the oil is moved by their joint effect towards the collector 4 and separation from water in the entire area of the angle.

(7) In the invention it is also possible to place the propulsion devices in such vicinity to the sides of the angle 3, i.e. the oil booms 2, that pulling and locking of the oil booms can be made in the same openings 7 through which the propulsion devices 6 are placed in the area of the angle 3.

(8) It is obvious to a person skilled in the art that with the advancement of technology, the basic idea of the invention may be implemented in various ways. The invention and its embodiments are thus not limited to the example described above; instead they may vary within the scope of the claims.