Polymer Sheath Composition to Block Acid Corrosion in Petroleum Ducts

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Solution Overview

Problem

Petroleum pipes transporting acidic compounds like H2S and CO2 under high pressure and temperature experience accelerated corrosion, threatening mechanical integrity due to migration of these compounds through polymer sheaths to metal parts, especially in offshore oil exploitation.

Innovation Solution

Incorporating chemically active fillers with high specific surface areas, such as metal oxides, into the polymer sheaths during extrusion, which react with H2S and CO2 to neutralize their corrosive effects, while optimizing the sheath's structure and composition to enhance mechanical resistance and reduce thickness for improved efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the polymer sheath thickness is increased to prevent acid compound migration, then corrosion protection is improved, but pipe weight and complexity increase

Engineering Contradiction:
Improvecorrosion protectionVSAvoidpipe weight
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent changes the chemical composition parameters of the polymer sheath by incorporating chemically active fillers (metal oxides, hydroxides, carbonates, or bicarbonates) that react with acidic compounds. This allows the sheath to provide adequate corrosion protection with reduced thickness compared to inert polymer materials, thereby reducing pipe weight while maintaining reliability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite polymer sheath material by combining inert polymer base material with chemically active filler particles. This composite structure provides both the barrier properties of the polymer matrix and the chemical neutralization capability of the filler particles, achieving effective corrosion protection with optimized thickness and weight.

Inventive Principle:
Principle #40Composite materials

2Reliability

If chemically active fillers are added to neutralize acid compounds, then corrosion resistance is improved, but the sheath thickness must be increased to provide sufficient neutralizing capacity

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidsheath thickness
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent applies local quality by concentrating chemically active filler particles within the polymer sheath matrix at strategic locations where acid compound penetration is most likely. This localized distribution of neutralizing agents provides effective corrosion resistance without requiring uniform thickening of the entire sheath, thus minimizing the increase in sheath thickness.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent optimizes the concentration and particle size parameters of the chemically active fillers to maximize neutralizing efficiency per unit thickness. By controlling these parameters, the sheath achieves sufficient corrosion resistance with minimal thickness increase.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If high concentrations of neutralizing agents are used to maximize neutralizing effect, then corrosion protection is improved, but the mechanical strength of the sheath decreases

Engineering Contradiction:
Improvecorrosion protectionVSAvoidsheath mechanical strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent formulates a composite material where chemically active filler particles are dispersed within a continuous polymer matrix. The polymer matrix provides the mechanical strength and structural integrity, while the filler particles provide corrosion protection. This composite structure allows high concentrations of neutralizing agents without sacrificing mechanical strength, as the load-bearing function remains with the polymer matrix.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent distributes chemically active fillers as discrete particles within the polymer matrix rather than using continuous high-concentration layers. This particle dispersion approach maintains local polymer continuity for mechanical strength while providing adequate neutralizing capacity throughout the sheath structure.

Inventive Principle:
Principle #3Local quality

4Productivity

If the sheath is made thinner to improve efficiency, then productivity is improved, but the neutralizing capacity against acid compounds is reduced

Engineering Contradiction:
Improveoperational efficiencyVSAvoidneutralizing capacity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent uses composite polymer-filler materials that provide enhanced neutralizing capacity per unit thickness. The chemically active filler particles react with acidic compounds that penetrate the polymer matrix, providing a secondary line of defense that extends the effective service life of thinner sheaths, thereby improving operational efficiency without sacrificing neutralizing capacity.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent ensures continuous neutralizing action throughout the sheath thickness by dispersing chemically active fillers throughout the polymer matrix. This continuous distribution of neutralizing agents maintains protection effectiveness even in thinner sheaths, allowing for improved productivity while preserving adequate neutralizing capacity.

Inventive Principle:
Principle #20Continuity of useful action

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 use of chemically active fillers with high specific surface areas significantly delays the passage of acidic compounds through the polymer sheath, extending the operational life of the pipes by reducing corrosion and maintaining mechanical integrity under harsh conditions.

Implementation Method 1

chemically active fillers with H2S and/or CO2 so as to irreversibly neutralize the corrosive effects of said acid compounds

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

products chemically active with the acid compounds (H2S and/or CO2) so as to irreversibly neutralize the corrosive effects

Methodology Applied
Scientific EffectNeutralization reaction: Chemical Bonding

Implementation Method 3

acidic compounds such as H2S and CO2 tend to migrate through the polymer sheath until they reach the metal parts of the pipe

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 4

Incorporating chemically active fillers with high specific surface areas, such as metal oxides, into the polymer sheaths during extrusion, which react with H2S and CO2 to neutralize their corrosive effects

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP2296871B2Duct with sheath having reduced perviousness to acid compounds
Publication Date: 2024.05.15 IFP ENERGIES NOUVELLES
  • EP2296871B2 patent drawingFigure 1~3

AI summary

The duct of the invention is intended for carrying a petroleum effluent containing at least one of the CO2 and H2S acid compounds. The duct includes at least a first metal element (3, 5) and a tubular sheath made of a polymer material (2, 4), the first element being provided outside the sheath. The sheath is made of a mixture of a polymer material and of a predetermined amount of products that are chemically active with said acid compounds in order to irreversibly neutralise the corrosive effects of said compounds and to limit the corrosive effects on said metal elements. The duct is characterised in that the chemically active products are fed into the sheath in the form of particles having a specific surface higher than 5 m2/g.