Hydrogen Supply Mixing Salt Cavern Purity

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Solution Overview

Problem

Hydrogen storage in salt caverns often results in impurities that do not meet pipeline purity specifications, leading to increased costs and complexity when attempting to reintroduce stored hydrogen into hydrogen pipeline systems, especially during periods of high demand or when production facilities are taken offline.

Innovation Solution

A method and system that dilute crude hydrogen streams from salt caverns with higher purity hydrogen from the pipeline to achieve acceptable product purity levels, allowing for cost-effective and simplified operation by mixing the streams within a processing facility before reintroduction into the pipeline.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If crude hydrogen stream is removed from salt cavern to meet customer demand, then hydrogen supply availability is improved, but hydrogen purity deteriorates due to contaminants from the salt cavern

Engineering Contradiction:
Improvehydrogen supply availabilityVSAvoidhydrogen purity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

A mixing facility acts as an intermediary between the salt cavern and the hydrogen pipeline. The crude hydrogen stream from the salt cavern is mixed with high-purity hydrogen from the pipeline in controlled proportions, producing a blended stream that meets purity specifications while maintaining supply availability. This intermediary mixing process resolves the contradiction between supplying hydrogen and maintaining purity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If large storage capacity is provided to effectively backup pipeline supply, then hydrogen supply reliability is improved, but storage facility complexity and cost increase

Engineering Contradiction:
Improvehydrogen supply reliabilityVSAvoidstorage facility complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The existing hydrogen pipeline system serves a dual function: it not only transports hydrogen to customers but also provides high-purity hydrogen for mixing with crude hydrogen from storage. This self-service approach allows the pipeline to contribute to its own backup capability, reducing the need for separate, complex purification facilities at the storage site.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The salt cavern storage facility is designed to work in conjunction with the existing hydrogen pipeline infrastructure. The pipeline serves multiple functions: customer supply, hydrogen transport, and providing dilution hydrogen for purity management. This multi-functionality reduces overall system complexity compared to having dedicated separate systems for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If crude hydrogen stream is directly introduced into pipeline without dilution, then operational simplicity is improved, but pipeline integrity deteriorates due to purity specification violations

Engineering Contradiction:
Improveoperational simplicityVSAvoidpipeline integrity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

A mixing facility serves as an intermediary that blends crude hydrogen with high-purity pipeline hydrogen in controlled proportions. This intermediary process maintains operational simplicity by using a straightforward mixing operation rather than complex purification, while simultaneously ensuring pipeline integrity by guaranteeing that the blended stream meets purity specifications before re-introduction.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 effectively meets customer demand while reducing operational costs and complexity by ensuring the hydrogen product stream meets purity specifications, allowing for efficient use of stored hydrogen and maintaining pipeline integrity.

Implementation Method 1

the stored hydrogen is removed from the salt cavern as a crude hydrogen stream that is thereafter diluted with higher purity hydrogen from the pipeline to form a hydrogen product stream at or below a product purity specification

Methodology Applied
Scientific EffectDilution:

Data Source

PatentEP2815169B1Hydrogen supply method and system
Publication Date: 2021.09.15 PRAXAIR TECH INC
  • EP2815169B1 patent drawingFigure 1
  • EP2815169B1 patent drawingFigure 2

AI summary

A method and system for supplying additional hydrogen from a reservoir of stored hydrogen in a salt cavern to a hydrogen pipeline to assist in meeting customer demand for hydrogen is provided. Contaminants introduced while the stored hydrogen stream is in the salt cavern may cause the crude hydrogen stream to not have the required product purity specification. The stored hydrogen is removed from the salt cavern as a crude hydrogen stream and thereafter diluted with higher purity hydrogen formed from the pipeline to form a hydrogen product stream at or below the product purity specification. The hydrogen product can be formed without removal of any of the contaminants in the crude stream, thereby creating a more cost effective and simplified supply process compared to conventional processes employing a salt cavern for hydrogen supply.