Salt Cavern Hydrogen Storage Stagnant Layer

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Solution Overview

Problem

The existing methods for storing hydrogen in salt caverns often require complex and costly carbon dioxide removal systems to meet pipeline specifications, adding complexity and expense to the operation.

Innovation Solution

A method and system where compressed hydrogen is injected into a salt cavern with a stagnant layer containing carbon dioxide, maintaining a minimum hydrogen volume to inhibit disturbance of the layer, thereby minimizing carbon dioxide contamination in the stored hydrogen stream, which is then introduced into a hydrogen pipeline without the need for carbon dioxide removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If carbon dioxide purification system is used to remove carbon dioxide from stored hydrogen stream, then pipeline specification compliance is achieved, but device complexity and operational expense increase

Engineering Contradiction:
Improvecarbon dioxide content in hydrogenVSAvoidpurification system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention extracts and removes the carbon dioxide-containing brine layer from the salt cavern before hydrogen storage. By taking out the harmful brine layer that contains carbon dioxide, the need for complex purification systems is eliminated, as the hydrogen stored above this removed layer remains free of carbon dioxide contamination

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention performs preliminary action by removing the carbon dioxide-containing brine layer before hydrogen is introduced into the salt cavern. This preliminary removal prevents carbon dioxide contamination from occurring in the first place, eliminating the need for subsequent purification steps

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If carbon dioxide purification system is used to remove carbon dioxide from stored hydrogen stream, then pipeline specification compliance is achieved, but operational expense increases

Engineering Contradiction:
Improvecarbon dioxide content in hydrogenVSAvoidoperational expense
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention extracts and removes the carbon dioxide-containing brine layer from the salt cavern before hydrogen storage. By taking out the harmful brine layer that contains carbon dioxide, the need for complex purification systems is eliminated, as the hydrogen stored above this removed layer remains free of carbon dioxide contamination

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention performs preliminary action by removing the carbon dioxide-containing brine layer before hydrogen is introduced into the salt cavern. This preliminary removal prevents carbon dioxide contamination from occurring in the first place, eliminating the need for subsequent purification steps

Inventive Principle:
Principle #10Preliminary action

3Quantity of substance

If hydrogen is stored in salt cavern with residual brine layer, then storage capacity is maximized, but carbon dioxide contamination of hydrogen stream occurs

Engineering Contradiction:
Improvehydrogen storage capacityVSAvoidcarbon dioxide contamination
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The invention extracts and removes the carbon dioxide-containing brine layer from the salt cavern before hydrogen storage. By taking out the harmful brine layer that contains carbon dioxide, the need for complex purification systems is eliminated, as the hydrogen stored above this removed layer remains free of carbon dioxide contamination

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention performs preliminary action by removing the carbon dioxide-containing brine layer before hydrogen is introduced into the salt cavern. This preliminary removal prevents carbon dioxide contamination from occurring in the first place, eliminating the need for subsequent purification steps

Inventive Principle:
Principle #10Preliminary 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

This approach significantly reduces the complexity and cost of hydrogen storage by maintaining low carbon dioxide levels in the stored hydrogen stream, eliminating the necessity for carbon dioxide removal, thus ensuring compliance with pipeline specifications.

Implementation Method 1

The stagnant layer has a carbon dioxide content that is a potential source of carbon dioxide contamination to the stored hydrogen stream. The flow rates and the velocities at which the compressed hydrogen feed stream is injected into the salt cavern and the stored hydrogen stream is withdrawn from the salt cavern are limited such that the stagnant layer is not disturbed and the carbon dioxide contamination of the stored hydrogen stream from the stagnant layer is inhibited.

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP2580156B2Hydrogen storage method
Publication Date: 2020.07.01 PRAXAIR TECH INC
  • EP2580156B2 patent drawingFigure 1
  • EP2580156B2 patent drawingFigure 2
  • EP2580156B2 patent drawingFigure 3

AI summary

A method and system for storing and supplying hydrogen to a hydrogen pipeline in which a compressed hydrogen feed stream is introduced into a salt cavern for storage and a stored hydrogen stream is retrieved from the salt cavern and reintroduced into the hydrogen pipeline. A minimum quantity of stored hydrogen is maintained in the salt cavern to produce a stagnant layer having a carbon dioxide content along the cavern wall and the top of a residual brine layer located within the salt cavern. The compressed hydrogen feed stream is introduced into the salt cavern and the stored hydrogen stream is withdrawn without disturbing the stagnant layer to prevent carbon dioxide contamination from being drawn into the stored hydrogen stream being reintroduced into the hydrogen pipeline.