Ionic Liquid Regeneration Using Membrane Separation for Water Removal
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Solution Overview
Problem
Environmental control systems (ECS) used for contaminant removal in environments like spacecraft cabins are hindered by large, heavy components that consume significant power and have short service lives due to high energy demands for water removal from ionic liquid mixtures used in contaminant absorption and desorption processes.
Innovation Solution
The implementation of an ionic liquid sorbent system with a scrubber and stripper, utilizing reverse osmosis (RO) or nanofiltration (NF) membranes in an ionic liquid regeneration assembly to separate liquid water from the ionic liquid mixture, reducing the volume of water and energy consumption, and extending the service life of vacuum pumps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional methods are used to remove water from ionic liquid mixture by evaporation and condensation, then water can be removed from the mixture, but energy consumption increases and system weight increases
Solution Approach 1:
The patent replaces the thermal evaporation-condensation system with a membrane separation system. Reverse osmosis membranes and nanofiltration membranes mechanically separate water from the ionic liquid mixture through selective permeability, eliminating the need for high-energy heating and phase change processes while maintaining effective water removal.
Solution Approach 2:
The patent introduces membrane materials as intermediary substances between the ionic liquid mixture and the separation process. These membranes act as selective filters that allow water molecules to pass through while blocking ionic liquid components, enabling water removal without direct thermal processing of the entire mixture.
2Productivity
If vacuum pumps are used to desorb contaminants from the stripper, then contaminants can be removed from the ionic liquid sorbent, but the vacuum pumps experience high energy demand and reduced service life
Solution Approach 1:
The patent changes the operating parameters of the desorption process by using membrane separation to remove water before vacuum pumping. This reduces the workload on vacuum pumps by eliminating the need to handle large volumes of water-vapor mixtures, thereby extending pump service life while maintaining contaminant desorption productivity.
Solution Approach 2:
The patent performs preliminary water removal from the ionic liquid mixture using membrane separation before the vacuum pumping step. This preliminary action reduces the volume and viscosity of the liquid to be pumped, decreasing energy consumption and mechanical stress on the vacuum pumps, which directly extends their operational lifespan.
3Productivity
If water is absorbed into the ionic liquid mixture during contaminant absorption, then contaminants can be removed from air, but the capacity of the ionic liquid sorbent decreases
Solution Approach 1:
The patent extracts water from the ionic liquid mixture using reverse osmosis and nanofiltration membranes. This extraction process removes water selectively while retaining the ionic liquid sorbent components, thereby restoring and maintaining the sorbent's capacity for contaminant absorption without compromising productivity.
Solution Approach 2:
The patent discards water from the ionic liquid mixture through membrane separation while recovering and retaining the ionic liquid sorbent. This separation process allows the sorbent to be reused multiple times without loss of capacity, maintaining high productivity while managing water content.
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
This approach reduces the size, weight, and power consumption of ECS components, enhancing their efficiency and longevity by minimizing water content in the ionic liquid mixture and optimizing contaminant processing.
Implementation Method 1
The ionic liquid regeneration assembly may include one or more reverse osmosis (RO) or nanofiltration (NF) membranes
Implementation Method 2
The ionic liquid regeneration assembly may include one or more reverse osmosis (RO) or nanofiltration (NF) membranes
Implementation Method 3
A contaminant removal system may include a scrubber that removes contaminants from an air stream through absorption using an ionic liquid sorbent
Implementation Method 4
a stripper that desorbs the contaminants from the ionic liquid sorbent
Implementation Method 5
A vacuum pump or other vacuum source downstream of the stripper drives desorption of the contaminants by generating a vacuum on the stripper
Data Source
AI summary
A contaminant removal system includes a scrubber and an ionic liquid regeneration assembly. The scrubber is configured to absorb a contaminant from an air stream into an ionic liquid sorbent in an ionic liquid mixture. The ionic liquid regeneration assembly is configured to desorb the contaminant from the ionic liquid sorbent and remove liquid water from the ionic liquid mixture. The ionic liquid regeneration assembly may include a stripper for desorbing the contaminant and one or more reverse osmosis (RO) or nanofiltration (NF) membranes for removing the liquid water from the ionic liquid mixture.