Undersea Vehicle Reactor Pressure Control for Borate Solubility
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Solution Overview
Problem
The solubility limitations of borate byproducts in hydrogen generation systems using sodium borohydride (NaBH4) lead to reactor clogging and reduced hydrogen storage efficiency, as borate becomes insoluble under certain temperature and pressure conditions, limiting the concentration of NaBH4 that can be used and reducing the reactor's lifespan.
Innovation Solution
Incorporating a back-pressure regulator to maintain elevated pressure in the reactor, pre-heating the reactor feed stream with a heat exchanger, and implementing a system-level water management strategy using hydrogen peroxide (H2O2) to ensure full solubility of borate byproducts and optimize water utilization, thereby increasing the effective storage concentration of NaBH4 and extending reactor lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If sodium borohydride concentration is increased to improve hydrogen storage efficiency, then hydrogen storage efficiency is improved, but borate byproduct solubility is exceeded causing reactor clogging
Solution Approach 1:
The patent changes the temperature parameter of the reactor system to maintain borate byproduct solubility. By operating at elevated temperatures (e.g., above 60°C), the solubility of borate increases, allowing higher sodium borohydride concentrations to be used without causing precipitation and reactor clogging, thus resolving the contradiction between hydrogen storage efficiency and reactor reliability
Solution Approach 2:
The patent introduces a heat exchanger as an intermediary component to control the temperature of the reactor feed stream. This intermediary device enables precise temperature management to maintain borate solubility while allowing high sodium borohydride concentrations, thereby preventing reactor clogging while maximizing hydrogen storage efficiency
2Productivity
If reactor pressure is reduced to improve waste removal, then waste removal is improved, but borate solubility decreases causing precipitation
Solution Approach 1:
The patent changes the pressure parameter by implementing a back-pressure regulator to maintain elevated pressure in the reactor system. This pressure maintenance prevents borate precipitation while still allowing effective waste removal through the liquid separator, resolving the contradiction between productivity and reliability
Solution Approach 2:
The patent implements a feedback control system using a back-pressure regulator that continuously monitors and adjusts reactor pressure to maintain conditions above the borate precipitation point. This feedback mechanism ensures that pressure is maintained at levels that prevent precipitation while still enabling effective waste removal, resolving the contradiction between waste removal efficiency and prevention of borate precipitation
3Object-affected harmful factors
If temperature is decreased to improve system safety, then system safety is improved, but borate solubility decreases leading to crystallization
Solution Approach 1:
The patent changes the temperature parameter by implementing controlled heating through heat exchangers and operating at elevated temperatures (e.g., 60-100°C). This temperature maintenance ensures borate remains soluble while the system incorporates safety features like pressure regulators and thermal management to address safety concerns, resolving the contradiction between system safety and prevention of borate crystallization
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 solution maintains full solubility of borate byproducts, allowing for higher NaBH4 feed concentrations and increased hydrogen storage efficiency, while preventing reactor clogging and extending the reactor's operational life.
Implementation Method 1
a back-pressure regulator that maintains a pressure in the reactor and an elevated temperature to prevent precipitation of the waste
Implementation Method 2
a heater that pre-heats at least one of a fuel or a reactant prior to entering a reactor
Implementation Method 3
a heat exchanger that cools the hydrogen
Implementation Method 4
a hydrogen separation chamber, and includes a gas permeable membrane or membranes that allow hydrogen gas to pass through the membrane while preventing aqueous solutions from passing through the membrane
Implementation Method 5
a hydrogen and liquid separator, wherein the liquid is stored in a reservoir
Implementation Method 6
a fuel cell capable of generating an electrical current when exposed to hydrogen
Implementation Method 7
producing hydrogen from a reaction involving a hydride solution such as sodium borohydride
Data Source
AI summary
The present invention includes an underwater vehicle power unit and method of operating the same comprising: a fuel and waste stack comprising one or more reactant or fuel storage bladders and one or more waste storage bladders; a heater; a reactor that generates hydrogen and waste; a hydrogen and waste separator; a back-pressure regulator; a hydrogen and liquid separator; a fuel cell; and a controller that controls the temperature of the heater, the flow of fuel into the reactor, the flow of hydrogen into the fuel cell, the flow of water that dilutes the fuel, the flow of waste from the reactor and/or the fuel cell into the one or more waste storage bladders.