Electrodialysis Bipolar Membrane Stack for Acid and Alkali Production
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Solution Overview
Problem
Existing electrodialysis methods face challenges in efficiently producing alkaline and acidic solutions, particularly with salts of high molecular size, and pose safety risks due to the production of dangerous gases like chlorine.
Innovation Solution
An electrodialysis device with a bipolar membrane stack comprising cation exchange membranes and a bipolar membrane, allowing for the simultaneous production of an alkali metal hydroxide and a Bronsted acid, while incorporating safety measures to mitigate gas hazards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electrolysis methods are used to produce alkaline and acidic materials, then chemical substances can be manufactured, but dangerous gases like chlorine are produced creating safety risks
Solution Approach 1:
The patent converts the harmful electrolysis process into a beneficial electrodialysis process by using ion-exchange membranes to selectively transport ions. The harmful chlorine gas production is eliminated by replacing direct electrolysis with membrane-based ion separation, where salt solutions are converted to alkaline and acidic materials without generating hazardous gases.
Solution Approach 2:
The patent introduces ion-exchange membranes as intermediary components between the salt solution and the products. These membranes mediate the ion transport process, allowing selective passage of ions through the membrane stack to produce alkaline and acidic materials while preventing the formation of dangerous gases like chlorine.
2Productivity
If conventional electrodialysis is used, then salt conversion is achieved, but salts of high molecular size cannot be efficiently processed
Solution Approach 1:
The patent segments the ion-exchange membrane into multiple layers with different selectivities and transport properties. This segmented structure allows efficient processing of salts with high molecular sizes by providing multiple pathways for ion transport, overcoming the limitations of single-layer membranes.
Solution Approach 2:
The patent applies local quality by creating different regions within the membrane stack with specific ion-exchange properties. Each layer or region is optimized for particular ion transport characteristics, enabling efficient processing of diverse salts including those with high molecular sizes by matching local membrane properties to the specific requirements of different salt types.
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 device efficiently produces alkali metal hydroxide and Bronsted acid solutions, including those with high molecular size salts like sodium citrate, while ensuring safety by removing hazardous gases, thereby enhancing operational safety and efficiency.
Implementation Method 1
a bipolar membrane stack arranged between the anode chamber and the cathode chamber; said bipolar membrane stack comprising x cell arrays, i=1...x, arranged in series between the cathode chamber and the anode chamber, wherein each cell array consists of y cells, k=1...y, and is defined by a first cation exchange membrane at the cathode side of the cell array, a second cation exchange membrane at the anode side of the cell array and a bipolar membrane arranged between the first cation exchange membrane and the second cation exchange membrane
Implementation Method 2
electrolysis methods are generally known in the field of chemical engineering for manufacturing acidic or alkaline materials
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
The present invention relates to an electrodialysis device (1110) for simultaneously producing an aqueous stream (B1) comprising an alkali metal hydroxide and an aqueous stream (A1) comprising a Bronsted acid and a process for simultaneously producing an aqueous stream (B1) comprising an alkali metal hydroxide and an aqueous stream (A1) comprising a Bronsted acid wherein the process is carried out in said electrodialysis device (1110).