Search

EP-4540469-B1 - SYSTEM AND METHOD FOR CAPTURING WATER FROM UNDERWATER AND OR COASTAL SOURCES WITH OVERFLOW BASIN

EP4540469B1EP 4540469 B1EP4540469 B1EP 4540469B1EP-4540469-B1

Inventors

  • FOURNO, ANDRE
  • CASTAGNE, MICHEL
  • DUPIN, Victor
  • BATOT, GUILLAUME
  • Darbouret, Myriam

Dates

Publication Date
20260513
Application Date
20230605

Claims (14)

  1. System for collecting water from at least one subsea water source comprising at least one separation means (1) for separating the water from the at least one source from sea water, each separation means (1) being connected to a separate overflow basin (5), each overflow basin (5) comprising an opening (A1, A2, A3, A4, A5, A6) for the inlet of water from the at least one source, the collecting system comprising at least one water recovery device (4, 150), each overflow basin (5) comprising an overflow wall (51, 130) configured such that water from the at least one source passes over said overflow wall (51, 130) to enter, under the effect of gravity, the at least one recovery device (4, 150) within each overflow basin (5), the overflow cross section (9, 135) of said overflow basin (5) being strictly greater than the cross section of said opening (A1, A2, A3, A4, A5, A6) of said overflow basin (5), characterized in that the overflow cross section (9, 135) of the overflow basin is located strictly above sea level (8).
  2. System for collecting water from at least one subsea water source according to Claim 1, wherein each separation means (1) is connected to the opening (A1, A2, A3, A4, A5, A6) of the overflow basin (5) by a pipe (3), the flow cross section for the flow of water along each pipe (3) being strictly smaller than the maximum flow cross section for the flow of water in the separation means (1) to which the pipe (3) is connected and in the maximum flow cross section for the flow of water in the overflow basin (5) to which the pipe (3) is connected.
  3. System for collecting water from a subsea water source according to one of the preceding claims, wherein the at least one separation means (1) comprises a shroud, preferably a flexible shroud.
  4. System for collecting water from at least one subsea water source according to one of the preceding claims, wherein the at least one separation means (1) comprises at least one non-return valve (10) capable of allowing the water from said source to pass to outside the separation means (1) and of preventing the passage of sea water towards the inside of the separation means (1).
  5. System for collecting water from at least one subsea water source according to one of the preceding claims, wherein said overflow wall (51, 130) of at least one overflow basin (5) is in the form of a concave bowl (30), the opening of this at least one overflow basin (5) being positioned at the bottom of the concave bowl (30), the recovery device (4) preferably surrounding the concave bowl (30).
  6. System for collecting water from at least one subsea water source according to one of Claims 1 to 4, wherein at least one overflow basin (5) is formed by a caisson comprising the overflow wall (130), the overflow wall (130) separating the overflow basin (5) on one side of the overflow wall (130) from the recovery device (4) on the other side of the overflow wall (130).
  7. System for collecting water from at least one subsea water source according to one of the preceding claims, wherein the system comprises adjusting means for adjusting the height of the overflow cross section (9, 135) of at least one overflow basin (5) at least at the time of installation of the collecting system, the system preferably comprising adjustment means for adjusting the height of the overflow cross section (9, 135) of at least one overflow basin (5) as a function of variations in flow rates and/or pressures and/or variation in the density of the sea water or of the water of the at least one source.
  8. System for collecting water from at least one subsea water source according to one of the preceding claims, wherein the vertical distance zc between the outlet of each subsea source and the level of the overflow cross section (9, 135) of each overflow basin (5) to which said outlet is connected is determined using the following formula: z c = ρ m ⋅ z s ⋅ g + Δ p ρ s ⋅ g where zs is the depth of the outlet (S1, S2, S3) of the relevant subsea source relative to sea level (8), g is the acceleration due to gravity, Δp is a predetermined overpressure value greater than or equal to zero and defined as a function of the characteristics of the relevant source, ρ m is the density of the sea water and ρ s is the density of the water of said relevant subsea source.
  9. System for collecting water from at least one subsea water source according to one of the preceding claims, wherein the at least one recovery device (4) includes a pump (24) configured to be turned on when the water level in the recovery device (4) exceeds a first predetermined threshold and configured to be turned off when the water level is below a second predetermined threshold, the second predetermined threshold being less than or equal to the first predetermined threshold.
  10. System for collecting water from at least one subsea water source according to one of the preceding claims, wherein the collecting system comprises a water storage means and a supply pipe (15) connecting the at least one water recovery device (4) to the storage means, the storage means being floating, and preferably capable of being disconnected from the supply pipe, or placed on the ground.
  11. System for collecting water from at least one subsea water source according to one of the preceding claims, wherein the at least one water recovery device (4) is floating and anchored to the ground by cables, preferably by tensioned cables, or placed on the ground onshore or offshore.
  12. System for collecting water from at least one subsea water source according to one of the preceding claims, wherein the at least one water recovery device (4) comprises an orifice for allowing the introduction of water from an outlet (S2) of an additional water source, the orifice allowing water from said additional water source (S2) to enter the at least one water recovery device (4) directly or indirectly, the at least one recovery device (4) preferably comprising control means for controlling the water level in the at least one water recovery device when the orifice is below the water level.
  13. System for collecting water from at least one subsea water source according to one of the preceding claims, wherein the collecting system is configured to collect water from a plurality of subsea sources, said collecting system comprising as many separation means (1) and overflow basins (5) as there are sources, each separation means (1) being connected to a separate overflow basin (5), the collecting system preferably comprising a single water recovery device (4) for recovering water from all the overflow basins.
  14. Method for collecting water from at least one subsea water source, wherein at least the following steps are carried out using the collecting system according to one of Claims 1 to 13: - Water from the at least one source is separated from the sea water at a subsea outlet by the at least one separation means (1); - The water separated from the sea water is conveyed to the opening (A1, A2, A3, A4, A5, A6) in the overflow basin (5); - The speed at which the water flows in the overflow basin (5) is slowed down by means of an overflow cross section (9, 135) of the overflow basin (5) that is strictly greater than the flow cross section for the flow of the water through the opening (A1, A2, A3, A4, A5, A6); - The water is caused to overflow from the overflow basin (5) and the water is recovered under the effect of gravity in the recovery device (4), the recovery device (4) being floating or placed on the ground, onshore or offshore, and then, preferably, the water is transferred from the water recovery device (4) to a floating storage means and the floating water storage means is towed to land by a boat.

Description

technical field The invention relates to the field of capturing water flowing into the sea (submarine, coastal sources) whose salinity is lower than that of seawater, in particular, fresh water or drinking water in order to use it for populations and/or crops and/or livestock. Previous technique There are many techniques for collecting water from springs that flow into the sea. We are particularly familiar with the patent application FR 2,857,389 which concerns a collection system allowing part of the fresh water to be discharged into the sea when the fresh water flow is too high, for example in the event of a flood at the source. However, this system can generate pressure variations at the source outlet into the sea, thus inducing a decrease in the source's flow rate and causing the source to exit through another channel. Another technique involves inserting a pipe directly at the spring outlet and creating a watertight connection between the pipe and the outlet, thus forcing the spring water into the collection system. This technique is described in the patent application. FR 2,792,664 This technique alters pressure balances and can therefore modify the spring's flow rate by creating a different, preferential pathway for the water via an outlet other than the one where the intake system was implemented. Furthermore, this blockage of the spring water can disrupt the local marine ecosystem, as the fauna and flora at the spring's outlet were accustomed to a lower salinity than that of seawater. Another technique involves using a bell jar above the source outlet. Patent applications WO2009/001,145 , FR2,926,569 , FR2,795,109 And WO2007/017,703 This technique involves the following: Because spring water has a lower density than seawater, it rises and is trapped inside the bell jar. A pipe and pump then carry the water to the surface or to the shore. However, the larger the bell jar, the more the spring water and seawater will mix, resulting in the collected water being saltier than the water coming from the source. Furthermore, the use of the pump creates a vacuum, disrupting the pressure balance and potentially causing some of the salt water to enter the system. Consequently, the recovered water will be saltier than the water leaving the bell jar. initially from the source. Furthermore, since the pump generates a vacuum, it might be necessary to implement real-time pump monitoring to adapt it to pressure variations. The use of real-time monitoring adds complexity to the system. Summary of the invention To overcome the drawbacks of the prior art, the invention seeks to capture water from a submarine spring without altering the pressure balance (or with a slight overpressure) at the spring's outlet, preventing the spring from finding another outlet and thus preventing the capture of salty seawater. By minimally altering the pressure balance, we mean that the pressure at the spring's outlet remains unchanged or is slightly overpressured, the value of which depends on the spring's conditions (presence or absence of other nearby spring outlets, pressure, temperature, salinity, etc.), and that the spring's flow rate will be minimally affected by any slight overpressure. For example, the flow rate of the spring with or without the invention's capture system varies by less than 5%. Therefore, unlike prior art systems that use a pump to extract fresh water from the spring, the invention does not generate a negative pressure at the spring's outlet. To this end, the invention relates to a water intake system from at least one water source opening via a subsea outlet, comprising at least one separation means for separating the source water from seawater (one separation means for each water source), each separation means being connected to an overflow basin comprising an opening for the inlet of the source water, and one (at least one) water recovery device (a single water recovery device or several, for example, a separate water recovery device connected to each source), each overflow basin comprising an overflow wall configured so that the source water flows over said overflow wall to enter the water recovery device by gravity. Furthermore, the overflow area at the outlet of each overflow basin is strictly greater than the cross-sectional area of the opening of the overflow basin in question, and the overflow (horizontal) area of the overflow basin is located above sea level. The invention relates to a system for capturing water from at least one underwater water source, comprising at least one separation means for separating the water from at least one source from seawater, each separation means being connected to a separate overflow basin, each overflow basin comprising an opening for the inlet of water from at least one source, the capture system comprising at least one water recovery device, each overflow basin comprising an overflow wall. configured so that water from at least one source passes over said overflow