A modular device for liquid/liquid gravity separation of two liquid phases of different densities from a liquid fluid, more preferably the aqueous phase and the oil phase of a crude oil that has preferably been degassed in part or in full, said modular separation device resting on the sea bottom, preferably at great depth of at least 1000 m, wherein the device comprises:
- a) at least one separation module, preferably a plurality of n separation modules, mi with i=1 to n, and n preferably being an integer in the range 5 to 10, each said separation module being supported by at least a first base resting on the sea bottom, said first base being anchored to the sea bottom by being fastened on an anchor, preferably fastened on a first pile of the “suction anchor” type embedded in the sea bottom, each separation module comprising:
- a.1) a fluid delivery pipe extending in an axial longitudinal direction X1X1;
- and
- a.2) at least one gravity separation pipe extending in rectilinear manner in an axial longitudinal direction X2X2, and arranged in such a manner that:
- a first end of said delivery pipe is connected to at least one first end of at least one separation pipe;
- and
- the second end of said delivery pipe is connected to a first outlet orifice of a first cylindrical manifold tank preferably extending in an axial longitudinal direction Y1Y1 perpendicular to the axial longitudinal direction X1X1 of said delivery pipe, said second end of each separation pipe being connected to a second inlet orifice of a second cylindrical manifold tank;
- and
- a.3) a tubular bend device suitable for enabling said fluid to be transferred between said first end of said delivery pipe and each said first end of each said separation pipe of said separation module;
- and
- b) a common manifold device supported by a second base resting on the sea bottom, said second base being anchored to the sea bottom by being fastened on an anchor, preferably being fastened on a second pile of the “suction anchor” type embedded in the sea bottom, said common manifold device having a first support structure supported by said second base and supporting:
- b.1) said first cylindrical tank comprising:
- at least one first inlet orifice, preferably situated in a low portion of said first tank, said first inlet orifice being connected or for connection to an undersea feed pipe resting on the sea bottom feeding or for feeding said first tank with said fluid;
- and
- a plurality of said first outlet orifices, each said first outlet orifice including or co-operating with a first closure valve, at least one said first outlet orifice being connected to a respective said second end of a said delivery pipe, said first outlet orifices being arranged side by side in the longitudinal axial direction Y1Y1 of said first tank;
- and
- b.2) a said second tank comprising:
- a plurality of second inlet orifices, each said second inlet orifice including or co-operating with a second closure valve, at least one said second inlet orifice being connected to a respective said second end of a separation pipe, said second inlet orifices being arranged side by side in the axial longitudinal direction Y2Y2 of said second tank;
- at least one upper second outlet orifice co-operating with a first export pump connected or for connection to a first removal pipe;
- and
- at least one lower second outlet orifice comprising or co-operating with a second export pump connected or for connection to a second removal pipe.