Low-Pressure Hydrogen Gasometer Venting for Membrane Permeation
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Solution Overview
Problem
Conventional pneumatic membrane gasometers face significant challenges in maintaining impermeability, particularly when storing hydrogen, leading to hydrogen permeation and accumulation, which poses safety risks due to its low explosion ignition point and wide explosion range, exacerbated by electrostatic charge generation.
Innovation Solution
A pneumatic membrane gasometer design featuring a first and second membrane with a third membrane forming a cavity, equipped with a passive natural ventilation system and duct to vent hydrogen losses externally, utilizing antistatic materials and channels on the third membrane to facilitate upward flow through a flexible bellows pipe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional first membrane (PVC-coated polyester fibre) is used to delimit the gas storage chamber, then the structure is simple and cost-effective, but hydrogen permeation occurs through the membrane due to its minimal porosity and small hydrogen molecular size, leading to safety risks
Solution Approach 1:
The single membrane structure is segmented into three distinct membranes: a first membrane for the gas storage chamber, a second membrane for the pressurization chamber, and a third membrane forming a cavity. This segmentation creates multiple barriers that collectively prevent hydrogen permeation while maintaining manufacturing feasibility through standardized membrane components.
Solution Approach 2:
The third membrane acts as an intermediary element between the first and second membranes, creating a cavity that serves as a buffer zone. This intermediary structure intercepts hydrogen that permeates through the first membrane before it can reach the pressurization chamber, allowing safe venting through the duct system.
2Ease of operation
If the pressurization chamber is maintained with air flow to provide thrust for gas supply, then the gas can be supplied at desired pressure, but hydrogen accumulation occurs in the cavity between membranes due to electrostatic charge generation and low explosion ignition point
Solution Approach 1:
The harmful effect of hydrogen permeation is converted into a beneficial safety feature by designing a dedicated venting duct that opens to the atmosphere. The hydrogen that does permeate through the first membrane is safely channeled outward through the third membrane and duct, preventing dangerous accumulation in the pressurization chamber while maintaining operational pressure control.
Solution Approach 2:
The cavity between the first and second membranes, bounded by the third membrane, serves as an intermediary safety zone. This cavity receives permeated hydrogen and provides a buffer before the hydrogen can reach the pressurization chamber, with the venting duct acting as an intermediary escape route to the atmosphere.
3Reliability
If a third membrane is added to form a cavity and improve impermeability, then hydrogen leakage is reduced, but the device complexity increases with additional membranes and sealing requirements
Solution Approach 1:
The third membrane performs multiple functions simultaneously: it forms the boundary of the safety cavity, provides an additional barrier against hydrogen permeation, and works in conjunction with the venting duct to safely discharge hydrogen. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity.
Solution Approach 2:
The cavity formed by the third membrane is nested within the existing gasometer structure, utilizing the space between the first and second membranes. The venting duct is nested within this cavity structure, creating a compact integrated system that adds safety functionality without proportionally increasing overall device complexity.
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 design effectively reduces hydrogen infiltration into the pressurization chamber, preventing accumulation and explosion risks by ensuring hydrogen leaks are vented externally, while minimizing electrostatic charge generation and maintaining safety.
Implementation Method 1
a natural passive ventilation system, adapted to vent any hydrogen losses towards the outside, including a duct adapted to connect said cavity to the external environment through said pressurization chamber
Implementation Method 2
Hydrogen permeability means that, even at low pressure (in the range of a few mbar of positive pressure), there is a constant passage of hydrogen through said first storage membrane
Implementation Method 3
a flexible bellows pipe with a first and a second end, where said first end is connected to said third membrane and said second end is connected to the outside
Data Source
AI summary
Disclosed is a pneumatic membrane gasometer for the storage of hydrogen gas at low pressure. The gasometer includes: a first bag-shaped membrane delimiting a hydrogen storage chamber; a second membrane partially delimiting a pressurization chamber superimposed, at least in part, on the storage chamber; a third membrane, placed resting on top of the first membrane, fixed in an impermeable manner at least to the second membrane, defining, with the first membrane, a cavity open towards the outside of the gasometer; hydrogen supply and discharge unit associated with the storage chamber; pressurization unit; mechanical anchor to a base surface of the first, second and third membranes; and a natural passive ventilation system to vent any hydrogen losses to the outside, including a duct adapted to connect cavity to the outside environment passing through the pressurization chamber.