Bipolar Membrane Electrodialyzer Operation to Suppress Scale Deposition
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Solution Overview
Problem
Bipolar membrane electrodialyzers face challenges in achieving high current efficiency due to deposition of scale in cation exchange membranes caused by divalent cations, which reduces mobility and increases drive voltage, hindering efficient operation in carbon recycling processes.
Innovation Solution
A method for operating a bipolar membrane electrodialyzer that includes adjusting acid and alkali solutions to contain a salt for decomposition, using brine produced in a carbon recycling process, and employing a bipolar membrane, cation exchange membrane, and anion exchange membrane to suppress scale deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrodialysis is performed using conventional bipolar membrane electrodialyzer, then acid and alkali can be produced from brine, but deposition of scale in cation exchange membrane occurs due to divalent cations, reducing current efficiency
Solution Approach 1:
The patent applies preliminary action by adjusting the acid solution and/or alkali solution to contain a salt to be decomposed before the electrodialysis process begins. This preparatory step ensures that the necessary ions are present in the solution to prevent scale deposition on the cation exchange membrane during operation, thereby maintaining high current efficiency and preventing the harmful effect of scale accumulation.
2Productivity
If brine with divalent cations is used as feed solution, then carbon recycling process can operate, but scale deposition increases and current efficiency decreases
Solution Approach 1:
The patent applies parameter changes by modifying the composition parameters of the acid solution and/or alkali solution used in the electrodialysis process. Specifically, the salt content and concentration are adjusted to optimal levels that prevent scale deposition while maintaining the ability to process brine with divalent cations. This parameter optimization enables the carbon recycling process to operate with high current efficiency despite the presence of divalent cations in the feed brine.
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 method achieves current efficiencies of 90% or higher and enables long-term operation in brine with low Ca concentrations by suppressing scale deposition, improving operational stability and efficiency.
Implementation Method 1
a bipolar membrane electrodialyzer including a bipolar membrane, a cation exchange membrane and an anion exchange membrane
Implementation Method 2
a bipolar membrane electrodialyzer including a bipolar membrane, a cation exchange membrane and an anion exchange membrane
Implementation Method 3
adjusting an acid solution and/or an alkali solution to contain a salt to be decomposed
Data Source
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AI summary
Provided are a bipolar membrane electrodialyzer where a current efficiency is high such that deposition of scale in a cation exchange membrane caused by divalent cations is suppressed, and a method for operating the same. The method is a method for operating a bipolar membrane electrodialyzer to produce an acid and an alkali from brine using a bipolar membrane electrodialyzer including a bipolar membrane, a cation exchange membrane and an anion exchange membrane, the method including: performing electrodialysis while adjusting an acid solution and/or an alkali solution to contain a salt to be decomposed.