Inert Gas Blanket for Stable Salt Cavern Roof
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Solution Overview
Problem
Leached storage caverns in salt formations with flat roofs are unstable due to low tensile strength, salt movement, and contamination risks from residual hydrocarbons, necessitating improved stability and purity measures.
Innovation Solution
A method involving solution mining with an inert gas blanket to create a domed roof structure, where leaching water is injected below the gas pad with controlled velocity and pressure, incrementally reducing diameter and raising the gas pad to form a stable dome shape, using nitrogen, helium, or argon gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flat roof is leached in a salt cavern, then the leaching process is simple, but the roof stability is poor due to low tensile strength
Solution Approach 1:
The patent applies curvature by transforming the flat roof geometry into a domed roof geometry. The leaching process creates a curved surface with radius of curvature R, where the dome shape provides inherent structural stability through its geometric form. This curvature distributes stresses more effectively across the roof structure, addressing the stability issue while maintaining the leaching process feasibility.
2Ease of manufacture
If liquid hydrocarbons are used as a blanket during leaching, then the process is cost-effective, but product contamination occurs
Solution Approach 1:
The patent replaces the liquid hydrocarbon blanket with an inert gas blanket (such as nitrogen or carbon dioxide). This inert atmosphere prevents contamination of the stored product while maintaining the protective blanket function. The gas blanket eliminates the harmful effects of hydrocarbon residue contact with the product, achieving both safety and purity requirements.
3Stability of the object's composition
If a domed roof is leached to increase stability, then roof stability improves, but the leaching process complexity increases
Solution Approach 1:
The patent employs parameter changes by systematically varying injection velocity, gas blanket pressure, and leaching fluid composition to achieve the desired domed geometry. By controlling parameters such as injection velocity (V) and maintaining gas pressure above injection pressure, the process achieves stable dome formation without requiring complex additional equipment or procedures.
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 enhances the overall stability of the salt cavern roof and prevents contamination by maintaining a clean environment, achieving a stable and contamination-free domed geometry through controlled water flow and gas pressure management.
Implementation Method 1
solution mining
Implementation Method 2
stream of leaching water which is injected below the inert gas pad with a velocity V, thereby leaching
Data Source
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AI summary
This method includes a solution mined underground salt cavern, wherein the salt cavern has a main body with a mean diameter of DN and an upper portion comprising an inert gas pad, a stream of leaching water which is injected below the inert gas pad with a velocity V, thereby leaching an Nth tier adjacent to the upper portion having a height H1 and a mean diameter DN+1 that is smaller than DN by a ratio R raising the inert gas pad by an amount A1, providing a stream of leaching water which is injected below the inert gas pad with a velocity V, thereby leaching an N+1th tier adjacent to the Nth tier having a height H2 and to a mean diameter DN+2 that is smaller than DN+1 by a ratio R, and repeating steps c and d a number of times T, thereby forming a stable roof.