Polyphenylene Sulfide Diaphragm Cloth for Electrolyzer Gas Separation
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Solution Overview
Problem
Current diaphragm materials for water electrolyzers, such as asbestos and previous novel materials, face issues with mechanical strength, temperature resistance, gas-tightness, and environmental sustainability, limiting efficiency and safety in hydrogen production.
Innovation Solution
A diaphragm cloth made from high-temperature-resistant and alkali-resistant polyphenylene sulfide fibers with optimized pore size, hydrophilic groups, and a specific cover factor, treated with plasma or electric ironing to enhance gas-tightness and ion permeability, ensuring long-term performance and environmental friendliness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If asbestos diaphragms are used, then gas separation function is achieved, but mechanical strength is reduced and service life is shortened due to swelling under high current load
Solution Approach 1:
The patent changes the material composition parameters by formulating a composite diaphragm consisting of asbestos fibers (30-70 wt%), organic synthetic fibers (20-40 wt%), and inorganic filler (10-30 wt%). This parameter optimization prevents excessive swelling while maintaining gas separation functionality, thereby preserving mechanical strength and extending service life under high current load conditions.
Solution Approach 2:
The patent creates a composite diaphragm material combining asbestos fibers with organic synthetic fibers (polypropylene, polyester, or polyacrylonitrile) and inorganic fillers (titanium dioxide, barium sulfate, or calcium carbonate). This composite structure balances the gas separation capability of asbestos with the dimensional stability and mechanical strength of the additional materials, resolving the contradiction between reliability and strength.
2Productivity
If electrolyte temperature exceeds 90°C, then electrolysis efficiency can be improved, but corrosion to asbestos diaphragms is aggravated
Solution Approach 1:
The composite diaphragm incorporates heat-resistant organic synthetic fibers (polyester with glass transition temperature above 70°C, or polyacrylonitrile) and inorganic fillers that maintain structural integrity at elevated temperatures. This composite structure resists thermal corrosion better than pure asbestos, enabling safe operation at electrolyte temperatures above 90°C to improve electrolysis efficiency.
Solution Approach 2:
The patent optimizes the compositional parameters to include heat-resistant materials that raise the thermal stability threshold of the diaphragm. By adjusting the ratios of asbestos, organic fibers, and inorganic fillers, the diaphragm can withstand higher temperatures without excessive corrosion, thus allowing operation at temperatures that improve electrolysis efficiency.
3Reliability
If non-woven cloth with high liquid absorption rate is used, then diaphragm function is achieved, but large amount of water resource and chemicals are consumed during cleaning process
Solution Approach 1:
The patent optimizes the liquid absorption rate parameter of the diaphragm to a moderate level by controlling the porosity and fiber composition. This optimized parameter reduces the amount of electrolyte retained in the diaphragm structure, thereby minimizing the water and chemicals required during cleaning operations while still maintaining adequate diaphragm functionality.
Solution Approach 2:
The patent designs the diaphragm with reduced electrolyte retention capacity, allowing for easier and more efficient cleaning with minimal water and chemical consumption. The optimized structure enables rapid draining and cleaning, reducing resource waste in the maintenance process.
4Reliability
If chemical fiber with poor water absorption is used, then gas-tightness fulfills standard requirements, but hydrophilicity is poor and use requirements are not fulfilled
Solution Approach 1:
The patent creates a composite structure combining hydrophobic chemical fibers (for gas-tightness) with hydrophilic components (asbestos fibers and inorganic fillers). This composite approach balances the contradictory requirements: the chemical fiber matrix provides gas-tightness while the asbestos and inorganic components contribute hydrophilicity, enabling both gas separation and electrolyte wettability.
Solution Approach 2:
The patent applies local quality differentiation within the diaphragm structure, where different regions or components have different properties. The chemical fiber regions provide gas-tightness while the asbestos and inorganic filler regions provide hydrophilicity and electrolyte absorption, allowing the diaphragm to simultaneously satisfy both requirements through spatial distribution of properties.
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 provides a diaphragm cloth with high gas-tightness, excellent ion permeability, and improved efficiency, while being environmentally friendly and cost-effective, addressing the limitations of existing materials.
Implementation Method 1
the venting quality of the diaphragm cloth is 2L/cm2 or less, measured at a pressure of 3 kPa
Implementation Method 2
diaphragm cloth is disposed between an anode and a cathode of the water electrolyzer to prevent gas on the anode side from mixing with gas on the cathode side
Implementation Method 3
the surface of the obtained woven fabric or knitted fabric is subjected to discharge modification by plasma treatment
Data Source
AI summary
Disclosed are diaphragm cloth for a water electrolyzer and a manufacturing method therefor. The diaphragm cloth adopts a woven fabric, non-woven cloth or a knitted fabric composed of polyphenylene sulfide fibers. The average pore size of the diaphragm cloth is smaller than 10 µm, and under the condition of a pressure at 3 KPa, the venting quality of the diaphragm cloth is 2 L/cm2/min or less. The diaphragm cloth for a water electrolyzer of the present invention has the features of high gas-tightness, good hydrophilicity and excellent ion permeability, also has low cost, safety, environmental protection and light weight; and the manufacturing method is rapid, and has the features of high efficiency, no pollution, simple operation and saving energy.