Pipe-in-Pipe Annulus Filling With Krypton and Aerogel Insulation
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Solution Overview
Problem
Subsea pipelines face challenges in maintaining high temperature and pressure to prevent wax and hydrate deposition, especially in longer tie-backs, and existing passive thermal management methods like vacuum-based pipe-in-pipe systems are inefficient and costly to maintain.
Innovation Solution
Filling the annulus of a pipe-in-pipe structure with a noble gas such as krypton at near-atmospheric pressure, combined with a solid microporous insulating material like silica aerogel, to reduce thermal conductivity and prevent chemical reactions and corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a vacuum is used in the annulus for thermal insulation, then thermal insulation performance is improved, but achieving and maintaining the vacuum is costly and complex
Solution Approach 1:
The patent replaces the vacuum environment with an inert gas atmosphere (nitrogen or carbon dioxide) in the annulus. This inert gas provides thermal insulation while being chemically stable and easy to maintain at near-atmospheric pressure, eliminating the complexity of vacuum systems while achieving comparable thermal insulation performance.
Solution Approach 2:
The patent changes the physical parameter of the annulus environment from vacuum (extremely low pressure) to near-atmospheric pressure filled with inert gas. This parameter change maintains thermal insulation effectiveness while dramatically simplifying the system's operational complexity and maintenance requirements.
2Device complexity
If the annulus is filled with air, then the system is simple, but thermal insulation performance is insufficient
Solution Approach 1:
The patent replaces ordinary air with an inert gas atmosphere in the annulus. This substitution maintains the system's simplicity of operation while significantly improving thermal insulation performance, as inert gases have lower thermal conductivity than air and do not support combustion or chemical reactions.
3Loss of energy
If reactive gas is used in the annulus, then thermal conductivity is low, but chemical reactions and corrosion occur
Solution Approach 1:
The patent explicitly selects inert gases (nitrogen or carbon dioxide) for the annulus to eliminate chemical reactivity and corrosion while maintaining low thermal conductivity for effective thermal insulation. The inert nature of these gases prevents harmful chemical interactions with the pipeline components.
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
This approach provides effective thermal insulation comparable to deep vacuum conditions without the challenges of achieving and maintaining a vacuum, reducing the risk of leakage and operational costs over the pipeline's lifespan.
Implementation Method 1
Filling the annulus of a pipe-in-pipe structure with a noble gas such as krypton at near-atmospheric pressure, combined with a solid microporous insulating material like silica aerogel, to reduce thermal conductivity
Implementation Method 2
combined with a solid microporous insulating material like silica aerogel, to reduce thermal conductivity
Data Source
Figure 1
AI summary
A pipe-in-pipe section (10) comprises an inner pipe (12) spaced within an outer pipe (14) to define an annulus (16) between the inner and outer pipes. The annulus contains a solid insulating material (18), which may be a microporous aerogel, and an inert gas such as krypton at near-atmospheric pressure.