Solid Hydride Dissolution for Anaerobic Submarine Propulsion
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Solution Overview
Problem
The storage of hydrogen in aqueous solutions for anaerobic propulsion systems in underwater vehicles is hindered by weight, size, and stability issues, leading to undesirable hydrogen emissions and uncontrolled crystallization, which limits diving autonomy and increases technical risks.
Innovation Solution
Storing borohydrides or aluminohydrides in solid form and using a process involving sequential dissolution and recirculation to produce hydrogen on board, optimizing the hydrogen mass fraction and eliminating crystallization risks through controlled aqueous solution creation and recycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If XH4 is stored in aqueous solution form, then hydrogen production is simplified, but weight increases and storage stability deteriorates
Solution Approach 1:
The patent changes the physical state parameter of XH4 from liquid/aqueous solution to solid form. This parameter change resolves the contradiction by eliminating the weight penalty associated with aqueous solutions while maintaining the ability to produce hydrogen through controlled hydrolysis. The solid XH4 provides both weight reduction and improved storage stability.
Solution Approach 2:
The patent utilizes the phase transition between solid XH4 and its dissolved state during hydrolysis. XH4 is stored in solid form for stable, compact storage, then transitions to dissolved state during controlled hydrolysis to produce hydrogen. This phase transition approach allows the system to benefit from both solid-state stability and solution-state reactivity.
2Productivity
If XH4 is stored in aqueous solution, then hydrogen can be produced continuously, but uncontrolled crystallization occurs and reliability decreases
Solution Approach 1:
The patent changes the storage state from aqueous solution to solid form, which eliminates crystallization issues entirely. Solid XH4 does not undergo unwanted crystallization or precipitation, thereby improving reliability while still allowing continuous hydrogen production through controlled hydrolysis when needed.
Solution Approach 2:
The patent prepares XH4 in advance in solid form with optimal properties for storage and controlled reaction. This preliminary preparation in solid form prevents crystallization problems that would occur with aqueous solutions, ensuring reliable operation throughout the mission duration.
3Volume of moving object
If solid XH4 is stored on board, then storage volume efficiency increases, but dissolution control becomes more difficult
Solution Approach 1:
The patent divides the solid XH4 storage into multiple separate tanks rather than using a single large storage system. This segmentation allows independent control and dissolution of each tank, making it easier to manage the dissolution process while maintaining high volume efficiency. Each tank can be dissolved separately according to mission requirements.
Solution Approach 2:
The patent implements a dynamic dissolution system where the state of XH4 transitions from static solid storage to dynamic dissolved state during hydrolysis. The system can control this transition dynamically, dissolving XH4 only when hydrogen production is required, thereby maintaining ease of operation while achieving compact solid-state storage.
4Productivity
If solid XH4 is conveyed and pumped on board, then hydrogen production is enabled, but noise increases and technical risks increase
Solution Approach 1:
The patent extracts and eliminates the solid conveying and pumping mechanisms from the system by using pre-positioned solid XH4 tanks that dissolve in place. This removal of mechanical conveying equipment eliminates the associated noise and technical risks while maintaining the ability to produce hydrogen through controlled hydrolysis of the solid XH4.
Solution Approach 2:
The patent replaces mechanical conveying and pumping systems with a chemical dissolution process. Instead of mechanically moving solid XH4 through pumps and conveyors, the system uses controlled hydrolysis where water is introduced to dissolve XH4 in situ, thereby eliminating mechanical noise and associated technical risks.
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 method enhances hydrogen production control, reduces emissions, increases storage efficiency, and minimizes technical risks by allowing continuous hydrogen production from solid borohydrides or aluminohydrides, improving diving autonomy and reducing noise and weight constraints.
Implementation Method 1
production of hydrogen (H2) by hydrolysis of borohydride or an aluminohydride, of formula XH4
Implementation Method 2
addition of an aqueous dissolution solution and an aqueous basic solution in one of the storage tanks
Implementation Method 3
Forced circulation of the mixture thus obtained within a dissolving box and said storage tank
Data Source
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AI summary
The present invention relates to a method of anaerobic propulsion of a submarine comprising an on-board hydride reserve in solid form and the sequenced dissolution of the solid hydride, as well as the corresponding production system.