Two-Stage Electrodialysis for Low-Loss Amine Solvent Recovery
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Solution Overview
Problem
Existing electrodialysis technologies for recovering CO2-lean amine solvent suffer from high amine loss rates and inability to effectively remove heat-stable salts (HSSs), leading to reduced CO2 absorption capacity, increased solvent viscosity, equipment corrosion, and increased cycle costs, while producing additional waste solutions.
Innovation Solution
A two-stage electrodialysis system comprising a C-A homogeneous membrane electrodialysis system and a BP-A bipolar membrane electrodialysis system, with pretreatment filtering, to sequentially remove HSSs and neutral degradation products, achieving a purified amine solution with less than 500 ppm HSSs concentration without generating additional waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional electrodialysis device is used to remove HSSs, then HSSs concentration is reduced, but amine loss rate increases to 15%-20% and additional waste solution is generated
Solution Approach 1:
The electrodialysis process is divided into two sequential stages: first stage removes HSSs from the amine solution, second stage treats the concentrated waste solution to recover neutral degradation products. This segmentation allows optimized treatment for each type of contaminant, reducing overall amine loss while achieving effective purification.
Solution Approach 2:
The system recovers neutral degradation products from the concentrated waste solution through the second stage electrodialysis treatment, converting what would be waste into recoverable material. This reduces amine loss by reclaiming valuable components that would otherwise be discarded with the waste stream.
2Quantity of substance
If traditional electrodialysis device is used to remove HSSs, then HSSs concentration is reduced, but additional waste solution is produced requiring special treatment
Solution Approach 1:
The second stage electrodialysis unit treats the concentrated waste solution to recover neutral degradation products, converting waste material into recoverable substances. This eliminates additional waste solution discharge by transforming it into a resource for potential reuse or environmentally benign disposal.
Solution Approach 2:
The concentrated waste solution containing neutral degradation products, which would normally be harmful waste requiring special treatment, is converted into a valuable stream for recovering neutral products. The harmful waste stream becomes a source of recoverable materials, turning a liability into an asset.
3Quantity of substance
If HSSs accumulate in absorbent, then CO2 absorption capacity is reduced, but removal of HSSs increases operation costs
Solution Approach 1:
The system recovers neutral degradation products from the waste stream, reducing the frequency and volume of absorbent replacement needed. By reclaiming valuable amine components, the system extends absorbent life and reduces operational costs associated with continuous absorbent make-up and disposal.
Solution Approach 2:
The electrodialysis system performs self-service by automatically removing HSSs and recovering neutral products, maintaining CO2 absorption capacity without requiring external intervention for absorbent replacement. This continuous self-purification reduces operational costs by minimizing downtime and material replacement expenses.
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 system achieves low amine loss rates, improves system stability, reduces operation costs, and enables secondary recycling of HSSs, ensuring stable CO2 absorption performance without producing additional waste solutions.
Implementation Method 1
Electrodialysis (ED) devices migrate anions from one solution chamber to another solution chamber in a directional manner under the action of anion and cation exchange membranes and an electric field
Implementation Method 2
When a voltage is applied to two electrodes, positive ions and negative ions move towards opposite electrodes and pass through the ion exchange membranes
Implementation Method 3
BP-A bipolar membrane electrodialysis system
Data Source
AI summary
A two-stage electrodialysis system and a method for recovering waste CO2-lean amine solvent are provided. The system includes an amine solution pretreatment filtering system, a C-A homogeneous membrane electrodialysis device, a BP-A bipolar membrane electrodialysis system, and a CO2 recovery and capture system. The C-A homogeneous membrane electrodialysis system includes a material chamber, a C-A homogeneous membrane electrodialysis device, a concentrated HSSs waste solution chamber, an electrode solution chamber, and corresponding pipelines and peristaltic pumps. The BP-A bipolar membrane electrodialysis system includes a secondary feed chamber, a BP-A bipolar membrane electrodialysis device, an acid liquor chamber, an electrode solution chamber, and corresponding pipelines and peristaltic pumps. The waste CO2-lean amine solvent enters the material chamber after passing through the amine solution pretreatment filtering system. The concentrated HSSs waste solution chamber is connected to the secondary feed chamber by a buffer tank.