Potassium Borohydride Aqueous Composition Low-Temperature Hydrolysis
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Solution Overview
Problem
Conventional dihydrogen generation cartridges using sodium borohydride experience low yield and safety issues at temperatures below 20°C due to precipitation of reaction products, which can inhibit the catalytic hydrolysis reaction and lead to sudden pressure increases, risking implosion.
Innovation Solution
An aqueous composition of hydrides comprising potassium hydroxide, potassium borohydride, and a second hydride with higher hydrogen storage capacity, along with an exothermic additive, is used, which maintains solubility of reaction products and regulates dihydrogen pressure, ensuring reliable and safe high-yield dihydrogen generation even at low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sodium borohydride is used as the hydride in conventional cartridges, then the cartridge operates safely at temperatures above 20°C with simple implementation, but the yield becomes low and safety issues occur at temperatures below 20°C due to precipitation of reaction products
Solution Approach 1:
The patent changes the chemical composition parameters of the aqueous medium by replacing sodium borohydride with potassium borohydride and adding specific salts (potassium chloride, sodium chloride, calcium chloride, magnesium chloride) to modify the solubility characteristics of reaction products. This parameter change prevents precipitation at low temperatures, maintaining both safety and high yield of dihydrogen generation across a wide temperature range.
Solution Approach 2:
The patent creates a composite aqueous composition by combining potassium borohydride with multiple salts (potassium chloride, sodium chloride, calcium chloride, magnesium chloride) in specific proportions. This composite material approach ensures that reaction products remain soluble at low temperatures, preventing catalyst deactivation and maintaining high productivity while ensuring safe operation.
2Use of energy by moving object
If the concentration of hydrides is increased to improve mass energy density, then the ratio of dihydrogen generated to cartridge mass improves, but the risk of uncontrollable runaway reaction increases at low temperatures due to product precipitation on the catalyst
Solution Approach 1:
The patent modifies the chemical environment parameters by introducing specific salts that alter the solubility product of reaction products. This allows higher hydride concentrations to be used safely, as the salts prevent precipitation of metaborate and other products even at elevated concentrations and low temperatures, thereby maintaining high mass energy density without increasing runaway risk.
Solution Approach 2:
The patent introduces salts (potassium chloride, sodium chloride, calcium chloride, magnesium chloride) as intermediary substances that mediate between the hydride and reaction products. These intermediaries maintain product solubility in the aqueous medium, preventing the formation of sealing joints that would isolate the catalyst and cause uncontrolled pressure buildup, thus enabling safe operation at high energy density.
3Reliability
If the catalytic system is isolated from the aqueous hydride composition to prevent runaway reactions, then safety is improved, but dihydrogen generation stops prematurely
Solution Approach 1:
The patent changes the solubility parameters of the reaction medium by adding specific salts, which keeps reaction products in solution rather than allowing precipitation. This parameter change maintains catalyst accessibility throughout the reaction process, allowing the system to safely complete dihydrogen generation without premature isolation of the catalytic system.
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 proposed composition and device configuration enable rapid and consistent dihydrogen generation with reduced risk of runaway reactions, maintaining high yield and safety by keeping reaction products dissolved and controlling pressure, even at temperatures below 0°C.
Implementation Method 1
an aqueous composition of hydrides dedicated to being hydrolyzed by a catalytic route to generate dihydrogen H2
Implementation Method 2
an exothermic additive chosen from a third hydride, different from potassium borohydride and second hydride, having a latent heat of hydrolysis reaction greater than 8 kJ/kg
Implementation Method 3
a water-soluble compound having a latent heat of dissolution less than -30 kJ/mol
Data Source
Figure 1~5
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Figure 10~12
AI summary
The invention relates to an aqueous composition of hydrides to be catalytically hydrolysed in order to generate dihydrogen H2, the aqueous composition of hydrides comprising an aqueous solvent and constituents that are at least partially, preferably completely, solubilised in the aqueous solvent, said constituents being: potassium hydroxide KOH, potassium borohydride KBH4, and a second hydride other than KBH4 and with a hydrogen storage capacity of more than 7.4%, optionally, an exothermic additive selected from a third hydride, different from the potassium borohydride and the second hydride, exhibiting hydrolysis reaction latent heat of more than 8 kJ/kg, a water-soluble compound exhibiting dissolution latent heat of less than -30 kJ/mol, and the mixtures thereof.