Cathodic Pipeline Pigging for In-Situ Corrosion Control
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Solution Overview
Problem
Pipeline pigs often get stuck due to debris and obstructions, leading to costly downtime and restricted pipeline flow, as existing systems are inefficient in cleaning and maintaining pipelines to prevent corrosion and blockages.
Innovation Solution
A pipeline pig equipped with a cathodic protection system that includes guide discs, an anode, and an impressed current source, using materials like mixed metal oxide, platinized niobium, or platinized titanium, to clean the pipeline surface and form a protective coating, preventing corrosion and facilitating movement through the pipeline.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pipeline pig is used to clean and maintain pipelines, then corrosion protection and debris removal are improved, but the pig frequently gets stuck due to debris and obstructions, causing downtime and restricted flow
Solution Approach 1:
The cathodic protection system is activated before the pig encounters debris, creating a protective environment that prevents corrosion buildup. The anode and current source are pre-positioned on the pig body, ready to immediately protect the pipeline interior surface as the pig moves through, preventing the formation of corrosive deposits that could cause sticking
Solution Approach 2:
The patent replaces purely mechanical cleaning approaches with an electrochemical cathodic protection system. Instead of relying solely on mechanical force to push through debris, the system uses electrochemical reactions at the anode to prevent corrosion and reduce adhesion of deposits to the pipeline wall, making the pig less likely to stick
2Speed
If flow channels are provided through the pipeline pig to regulate speed, then the pig speed is controlled, but the maximum fluid force that can be applied is reduced, increasing the likelihood of getting stuck
Solution Approach 1:
The pipeline pig is designed with multi-functionality: it serves both as a speed-regulating device with flow channels and as a cathodic protection system with anode and current source. This allows the pig to maintain controlled speed while simultaneously preventing corrosion and reducing debris adhesion through electrochemical means, compensating for the reduced fluid force
3Productivity
If the pipeline pig gets stuck, then flow of pipeline fluid is restricted or impeded, but recovery requires cutting the pipeline, which is costly and causes extended downtime
Solution Approach 1:
The pipeline pig incorporates a disposable or replaceable battery-powered cathodic protection system. The battery and anode assembly can be easily replaced on the pig body without requiring pipeline cutting. This transforms a complex recovery operation into a simple pig replacement task, significantly reducing recovery complexity and restoring flow continuity
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
The cathodic protection system effectively cleans the pipeline surface, prevents corrosion, and ensures the pipeline pig can move efficiently, reducing the likelihood of getting stuck and minimizing downtime by maintaining a debris-free and corrosion-free environment.
Implementation Method 1
an anode and an impressed current source, where the interior of the pipeline acts as a cathode when current is applied from the current source so that ions flow from the anode, through the fluid, to the interior of the pipeline
Data Source
AI summary
Apparatus and method for cleaning the inner surface of a pipeline from deposits and for forming a protective coating are disclosed. The apparatus includes a cleaning tool which is caused to move in the interior of the pipeline by a flow of a fluid, the cleaning tool comprising a plurality of guide discs engaging the pipeline surface and mounted along a longitudinal axis of the cleaning tool, an anode positioned inside the cleaning tool, and an impressed current source electrically connected to the anode and the interior of the pipeline, the interior of the pipeline acting as a cathode when current is applied from the current source so that ions flow from the anode, through the fluid, to the interior of the pipeline.