FPSO Anode With Insulative Portion For At-Sea Maintenance
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Solution Overview
Problem
Existing cathodic protection systems for FPSO vessels require drydocking for maintenance, which is costly and disruptive, and do not account for the unique complexities of floating production units like mooring chains and changing drafts, leading to potential corrosion issues.
Innovation Solution
A Floating Production, Storage and Offloading (FPSO) vessel anode with a conductive and insulative portion, along with a pressure-tight container, allows for the installation and maintenance of the ICCP system while the vessel is in the water, using a connector to transmit electrical current away from the hull and reducing the risk of damage, and a method to attach the anode to the hull without drydocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional cathodic protection systems are used on FPSO vessels, then corrosion protection is provided, but drydocking is required for maintenance which is costly and disruptive
Solution Approach 1:
The anode is divided into multiple modular segments that can be independently installed, removed, and replaced. Each segment contains an insulative portion that electrically isolates adjacent anode segments, allowing individual maintenance without shutting down the entire cathodic protection system or requiring drydocking.
Solution Approach 2:
The system enables at-sea maintenance where anodes can be replaced while the vessel remains floating and operational. The modular design with quick-connect mechanisms allows the crew to perform maintenance operations without external assistance or drydocking, maintaining continuous corrosion protection during the process.
2Speed
If anodes are mounted flush to the hull for reduced drag, then hydrodynamic efficiency is improved, but access for maintenance and replacement becomes difficult
Solution Approach 1:
The anode incorporates a movable or extendable mounting mechanism that allows the anode to be positioned flush against the hull during normal operation for optimal hydrodynamics, and extended or repositioned during maintenance operations to provide accessible connection points for electrical connections and inspection.
Solution Approach 2:
The insulative portion serves as an intermediary element that provides both electrical isolation and a mechanical interface for mounting and maintenance. This intermediate structure allows the anode to maintain close proximity to the hull for drag reduction while providing accessible points for electrical connections and inspection without requiring the anode itself to be far from the hull.
3Reliability
If the anode is positioned close to the hull for effective corrosion protection, then protection efficiency is improved, but electrical current may cause damage to the hull
Solution Approach 1:
The insulative portion acts as an intermediary barrier between the conductive anode and the hull. It electrically isolates the anode from the hull while allowing the anode to remain positioned close to the hull surface for effective corrosion protection. The insulative material prevents direct electrical contact that could cause current damage to the hull structure.
Solution Approach 2:
The anode design incorporates localized conductive regions that contact the hull at specific protected areas, while insulative regions prevent current flow to adjacent areas. This local differentiation allows efficient corrosion protection at the anode-hull interface while preventing harmful current distribution to surrounding hull structures through the insulative portions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the control of corrosion on FPSO vessel hulls without the need for drydocking, reducing operational disruption and maintenance costs, while ensuring the integrity and safety of the hull.
Implementation Method 1
a first portion (32) (electrically conductive outer surface (33))
Implementation Method 2
a second portion (34) (electrically insulative outer surface (35))
Implementation Method 3
The basic principle of the ICCP method is the vulnerable metal is supplied with a surplus of electrons. The excess electrons reduce the potential of the metal (cathodic polarization) and tend to drive the anodic corrosion reaction in reverse.
Data Source
Figure 1
AI summary
A method of attaching an anode to a hull of a vessel is described. The method includes attaching a container to an inside surface of the hull of the vessel, the container having a through-bore and two open ends, one of the open ends being attached to the inside surface of the hull, the container including an isolation valve. A plug with an aperture is fitted in the remaining open end of the container. A cutting device is pushed in through the plug and through-bore of the container and a hole is cut in the hull of the vessel using the cutting device, operated from outside the container. The anode is pushed out through the hole in the hull of the vessel. The anode and an apparatus including the anode are also described.