Fpso External Anti-Corrosion Device

The present invention relates to a field of anti-corrosion technology, particularly to an FPSO external anti-corrosion device.

FPSO (Floating Production Storage and Offloading), also known as floating oil storage and offloading unit, is used for the preliminary processing and storage of crude oil and is referred to as “marine oil factory”. The hull of an FPSO is often exposed to environments containing salt mist, moisture, and seawater, etc., causing severe electrochemical corrosion due to the surrounding media, leading to serious structuralcorrosion. Corrosion reduces the mechanical properties of structural materials and shortens the service life. FPSOs, being far from the coast, cannot be docked for regular maintenance and repairs like ships, making anti-corrosion measures for FPSO hulls very necessary.

Currently, anti-corrosion measures for FPSO hulls are basically the same as those for conventional ships, primarily involving coating and cathodic protection. Generally, the exterior surface below the waterline of the hull adopts combined protection, while the exterior surface above the waterline adopts coating protection.

However, sacrificial anode protection current is not adjustable, and is not suitable for high-resistance environments, limiting the applicable environments of FPSOs. The lifespan of sacrificial anodes is relatively short, requiring frequent replacement for FPSOs operating at sea for extended periods. Since sacrificial anodes are installed on the hull surface, frequent replacement and maintenance affect the stability of the hull structure. Additionally, sacrificial anodes consume non-ferrous metals, causing environmental pollution.

The present invention provides an FPSO external anti-corrosion device to solve the aforementioned problems.

The FPSO external anti-corrosion device includes: a hull; support arms; composite cables; and auxiliary anodes, wherein at least two of the support arms are provided on one side of the hull, ends of the support arms extending away from the hull, the ends of the support arms being connected to the composite cables, the composite cables being tensioned by the support arms, and the auxiliary anodes being arranged on the composite cables.

The FPSO external anti-corrosion device further includes a lifting device, wherein the lifting device includes a winch, a lifting platform, steel cables, and rails, the winch being installed on the hull, the winch being connected to the lifting platform via the steel cables, the lifting platform being arranged on the rails, the rails being vertically arranged on an outer side of the hull, and the support arms being fixed on the lifting platform.

The FPSO external anti-corrosion device further includes a lifting device, wherein the lifting device includes a motor and a reducer, the motor being installed on the hull and connected to the support arms via the reducer, and a winch being able to drive the support arms to rotate through the reducer, causing the composite cables to rotate to a top of the hull.

The FPSO external anti-corrosion device further includes a lifting device, wherein the lifting device includes a winch and steel cables, the winch being installed on the hull and connected to the ends of the support arms via the steel cables, the support arms being hinged to a side of the hull, and the winch being able to lift the support arms via the steel cables.

Further, the support arms are hinged to a side of the hull via installation shafts, axes of the installation shafts being perpendicular to a horizontal plane, the installation shafts being connected to a driving structure, and the driving structure being used to drive the installation shafts to rotate.

Further, the support arms are hinged to a side of the hull via installation shafts, axes of the installation shafts being parallel to a bow-and-stern line of the hull, the installation shafts being connected to a driving structure, and the t driving structure being used to drive the installation shafts to rotate.

Further, the support arms are hydraulic telescopic arms or electric telescopic arms, the support arms being installed on a side of the hull and located below a water surface, and the support arms being parallel to a horizontal plane.

Further, the support arms are hydraulic telescopic arms or electric telescopic arms, the support arms being installed on the hull, the support arms extending obliquely downward, with a support member provided between the support arms and a side of the hull, and the ends of the support arms extending below a water surface.

Further, the ends of the support arms are provided with tensioning devices, the tensioning devices being able to tension the composite cables.

The FPSO external anti-corrosion device according to the present invention provides auxiliary anodes outside a hull via support arms, solving the problem of underwater anti-corrosion for FPSOs. Furthermore, a protective current is adjustable, offering a wider range of applications. The external installation of auxiliary anodes does not affect the hull's structure, ensuring the stability and reliability of the hull structure. Additionally, the FPSO external anti-corrosion device is suitable for existing FPSOs, and the external anti-corrosion structure according to the present invention can be implemented with minimal modifications to the original hull structure, making it convenient to use and easy to maintain.

In the drawing:. Hull;. Support arm;. Composite cable;. Auxiliary anode;. Winch;. Lifting platform;. Steel cable;. Rail;. Motor;. Reducer;. Installation shaft;. Driving structure;. Tensioning device

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments the present invention. Obviously, the embodiments to be described are some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by a person skilled in the art without creative efforts are within the protection scope of the present invention.

As shown in, the present embodiment discloses an FPSO external anti-corrosion device, including: a hull; support arms; composite cables; and auxiliary anodes, wherein

The present embodiment also includes a lifting device, wherein the lifting device includes a winch, a lifting platform, steel cables, and rails, the winchbeing installed on the hull, the winchbeing connected to the lifting platformvia the steel cables, the lifting platformbeing arranged on the rails, the railsbeing vertically arranged on an outer side of the hull, and the support armsbeing fixed on the lifting platform.

The ends of the support armsare provided with tensioning devices, the tensioning devicesbeing able to tension the composite cables.

In the present embodiment, the support armsare parallel to a horizontal plane and vertically fixed to the lifting platform. The lifting platformis provided with a slider that can move along the rails. The steel cablesare fixedly connected to the lifting platform. The winchpulls the steel cables, driving the lifting platformto move, thus allowing the support armsto move with the lifting platformso that the composite cablescan leave the water surface or go underwater.

The size and number of auxiliary anodes are calculated and determined based on the area of the structure to be protected, the coating situation, operating conditions, the designed protection years, etc. The position of the auxiliary anodes is calculated and determined using cathodic protection numerical simulation software. The auxiliary anodes are installed on the composite cables. Based on the hydrodynamic calculation results of the composite cables, corresponding mechanical calculations are carried out to determine the specifications of the composite cables, the fixing device between the composite cables and the lifting platform, and the tensioning device.

The tensioning devicecan adopt turnbuckle bolts or waterproof electric telescopic rods, as well as other forms of tensioning structures. By prefabricating the tensioning force to tension the auxiliary anode composite cables, the overall rigidity of the composite cables is improved, effectively resisting alternating stress loads from seawater waves and flow, preventing external damage under extreme marine conditions, and preventing the composite cables from colliding with the hull under the action of ocean currents.

During normal operation, the composite cablesand the auxiliary anodesare both underwater. For maintenance or repair, the composite cablescan be pulled up by the winch.

The FPSO external anti-corrosion device according to the present invention can be implemented with minimal modifications to the original structure of the FPSO, and thus is easy to install, does not require operation on the hull during maintenance, does not affect the hull structure, and is convenient for maintenance.

The FPSO external anti-corrosion device according to the present invention adopts an applied current cathodic protection and provides auxiliary anodes outside a hull via support arms, solving the problem of underwater anti-corrosion for FPSOs. Furthermore, a protective current is adjustable, offering a wider range of applications. The external installation of auxiliary anodes does not affect the hull's structure, ensuring the stability and reliability of the hull structure. Additionally, the FPSO external anti-corrosion device is suitable for existing FPSOs, and the external anti-corrosion structure according to the present invention can be implemented with minimal modifications to the original hull structure, making it convenient to use and easy to maintain.

As shown in, the present embodiment differs from Embodiment 1 in that the lifting device includes a motorand a reducer, the motorbeing installed on the hulland connected to the support armsvia the reducer, and a winchbeing able to drive the support armsto rotate through the reducer, causing the composite cablesto rotate to a top of the hull.

In the present embodiment, the motorand the reducerare installed on the side of the hull, a torque is transmitted through the motorand the reducerto rotate the support arms, and the axes of rotation of the support armsare parallel to the bow-and-stern line of the hull.

During operation, the support armsextend obliquely downward into the water, providing anti-corrosion protection for the hull surface. For maintenance, the motoris activated to rotate the support armsto the top of the hullfor inspection.

As shown in, the present embodiment differs from Embodiment 1 in that the lifting device includes a winchand steel cables, the winchbeing installed on the hulland connected to the ends of the support armsvia the steel cables, the support armsbeing hinged to a side of the hull, and the winchbeing able to lift the support armsvia the steel cables.

In the present embodiment, the winchdrives the support armsthrough the steel cables, allowing the support armsto rotate and thus causing the composite cablesprovided at the ends of the support armsto enter or leave the water.

As shown in, the present embodiment differs from Embodiment 1 in that the support armsare hinged to a side of the hullvia installation shafts, axes of the installation shaftsbeing perpendicular to a horizontal plane, the installation shaftsbeing connected to a driving structure, and the driving structurebeing used to drive the installation shaftsto rotate.

In the present embodiment, the driving structureadopts a waterproof motor. The motor drives the installation shaftsand the support armsto rotate, and other forms of driving structures can also be adopted. The rotation of the support armsmakes the composite cablesand the auxiliary anodeslean against the side of the hull, allowing maintenance personnel to carry out inspections through rope ladders or a hull maintenance platform.

As shown in, the present embodiment differs from Embodiment 1 in that the support armsare hinged to a side of the hullvia installation shafts, axes of the installation shaftsbeing parallel to a bow-and-stern line of the hull, the installation shaftsbeing connected to a driving structure, and the driving structurebeing used to drive the installation shaftsto rotate.

In the present embodiment, the driving structureadopts a waterproof motor. The motor drives the installation shaftsand the support armsto rotate, and other forms of driving structures can also be adopted. The rotation of the support armsmakes the composite cablesprovided at the ends of the support armsto enter or leave the water. Once out of the water, the composite cablescan rotate to a side of the hull, and thus, maintenance personnel can perform inspections and maintenance on the hull.

As shown in, the present embodiment differs from Embodiment 1 in that the support armsare hydraulic telescopic arms or electric telescopic arms, the support armsbeing installed on a side of the hulland located below a water surface, and the support armsbeing parallel to a horizontal plane.

In the present embodiment, the support armsare telescopic arms, installed on both sides of the hull. The support armscan be driven hydraulically or electrically. During normal operation, the support armsextend. For maintenance, the support armsretract.

As shown in, the present embodiment differs from Embodiment 6 in that the support armsare installed on the hull, the support armsextend obliquely downward, with a support member provided between the support armsand a side of the hull, and the ends of the support armsextend below a water surface.

In the present embodiment, the support armsare installed on the side of the hull, and thus, the power structure of the support armsis protected better. The ends of the support armsextend below the water surface. The support armseach have a certain angle with the horizontal plane, and a support member is provided between the support armsand the hull to maintain the stability and firmness of the support arms. During normal operation, the support armsextend. For maintenance, the support armsretract, bringing the composite cables and the auxiliary anodes close to the hull for convenient inspection.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, a person skilled in the art should understand that the technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features thereof can be equivalently substituted. However, these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.