Humidity Swing Sorbent for Low-Energy CO2 Capture
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Solution Overview
Problem
Current methods for removing carbon dioxide from air are inefficient due to high energy expenditure in CO2 recovery and sorbent regeneration, particularly in processes using pressure swing or thermal swing adsorbents like zeolites, amines, and activated alumina.
Innovation Solution
A method and apparatus utilizing a sorbent that captures CO2 when dry and releases it with humidity, combined with thermal swings and a heat exchanger to optimize regeneration, employing a substrate with embedded cations and hydroxide ions to facilitate CO2 capture and release, and using a bias voltage to manage hydroxide ions for efficient CO2 extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If pressure swing or thermal swing adsorbents are used to remove CO2 from air, then CO2 capture capability is improved, but energy consumption increases
Solution Approach 1:
The patent employs humidity swing adsorption, which changes the physical-chemical state of the sorbent material by varying humidity levels rather than using high energy-consuming pressure or temperature changes. The sorbent material's CO2 adsorption capacity is modulated by humidity, allowing CO2 capture at high humidity and release at low humidity, thereby reducing energy consumption while maintaining effective CO2 capture.
Solution Approach 2:
The invention utilizes the phase transition or state change of water (from liquid to vapor) to drive the adsorption and desorption cycles. By controlling the humidity environment, the sorbent material transitions between CO2-binding and CO2-releasing states, enabling efficient CO2 separation without requiring the high energy input associated with traditional thermal or pressure swing methods.
2Duration of action of stationary object
If traditional sorbent regeneration methods are used, then sorbent reusability is improved, but energy expenditure increases
Solution Approach 1:
The patent uses humidity as the controlling parameter for sorbent regeneration instead of high temperature or pressure changes. The sorbent is regenerated by exposing it to low humidity conditions, which causes CO2 release and restores the sorbent's CO2 capture capacity. This humidity-based regeneration method significantly reduces energy expenditure compared to traditional thermal regeneration while ensuring continuous sorbent reusability.
3Object-affected harmful factors
If CO2 is removed from air to compensate for emissions, then environmental impact is reduced, but process complexity increases
Solution Approach 1:
The patent employs sorbent materials that automatically respond to humidity changes by adsorbing or desorbing CO2, eliminating the need for complex control systems, sensors, and actuators required in traditional pressure or thermal swing systems. The humidity-driven mechanism provides inherent self-regulation, where the sorbent naturally cycles between capture and release modes based on environmental humidity, thereby reducing process complexity while achieving effective CO2 removal for environmental mitigation.
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 energy consumption by leveraging humidity and thermal swings to regenerate the sorbent, achieving efficient CO2 capture and release, with the sorbent capable of reaching high CO2 loading concentrations and maintaining performance across varying humidity levels.
Implementation Method 1
a sorbent that captures the contaminant, such as carbon dioxide (CO2) when it is sufficiently dry and releases the contaminant to a contained atmosphere when the sorbent is exposed to water or humidity
Implementation Method 2
the heat retained by the sorbent after regeneration is conserved by passing the sorbent through a heat exchanger
Data Source
AI summary
The present invention provides a method and apparatus for removing a contaminant, such as carbon dioxide, from a gas stream, such as ambient air. The contaminant is removed from the gas stream by a sorbent which may be regenerated using a humidity swing, a thermal swing, or a combination thereof. The sorbent may be a substrate having embedded positive ions and individually mobile negative ions wherein the positive ions are sufficiently spaced to prevent interactions between the negative ions. Where a thermal swing is used, heat may be conserved by employing a heat exchanger to transfer heat from the regenerated sorbent to an amount of sorbent that is loaded with the contaminant prior to regeneration.