Membrane Air Purification with Equal-Pressure CO2 Removal
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Solution Overview
Problem
Conventional air purifying systems require high carbon dioxide selectivity membranes with low permeation rates, leading to increased system size and cost, and high air-conditioning loads due to the need for large membrane surface areas.
Innovation Solution
An air purifying system utilizing a carbon dioxide remover with a gas permeable membrane having micropores of 50 nm or less, where the gas pressure in the first and second spaces is adjusted to be equal, allowing carbon dioxide to permeate from the first space to the second space and oxygen to permeate back, while minimizing heat mixing and reducing air-conditioning loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional high carbon dioxide selectivity membranes are used, then carbon dioxide removal efficiency is improved, but membrane permeation rate decreases and system size increases
Solution Approach 1:
The patent changes the operating parameters by equalizing gas pressure between the first space (feed side) and second space (permeate side), eliminating the need for decompression pumps and enabling high permeation rates without compromising carbon dioxide selectivity. This parameter optimization allows achieving both high removal efficiency and compact system size
Solution Approach 2:
The patent employs composite membrane structures combining multiple layers with different functions: a support layer providing mechanical strength, an active separation layer with micropores of 50 nm or less for selective carbon dioxide permeation, and potentially functional coatings. This composite structure achieves high selectivity and permeation rate simultaneously, reducing the required membrane area and system size
2Productivity
If large membrane surface area is used to achieve predetermined carbon dioxide removal amount, then carbon dioxide removal efficiency is improved, but system cost increases
Solution Approach 1:
By changing the pressure parameter to equal conditions on both sides of the membrane, the system achieves high permeation flux without requiring large membrane areas. This reduces material costs, manufacturing complexity, and overall system cost while maintaining the required carbon dioxide removal amount
Solution Approach 2:
The patent replaces the conventional mechanical decompression pump system with a pressure-equalization system, eliminating complex mechanical components and reducing system cost. The carbon dioxide removal is achieved through membrane permeation driven by concentration gradients rather than pressure differences, simplifying the overall system
3Productivity
If gas pressure difference is created across the membrane to enhance permeation, then carbon dioxide removal rate is improved, but air-conditioning load increases due to heat mixing
Solution Approach 1:
The patent applies equipotentiality by equalizing the gas pressure in the first space and second space, eliminating pressure-driven heat transfer across the membrane. This prevents unwanted heat mixing that would increase air-conditioning loads, while still achieving high carbon dioxide permeation rates through concentration gradient-driven diffusion
Solution Approach 2:
By optimizing the pressure parameter to be equal on both sides, the system achieves decoupling between mass transfer (carbon dioxide permeation) and heat transfer (thermal mixing). This allows high productivity without the penalty of increased air-conditioning energy consumption
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 efficiently purifies air while reducing air-conditioning loads and preventing system size increases, achieving efficient carbon dioxide removal and oxygen supply with minimal heat exchange.
Implementation Method 1
a carbon dioxide remover with a gas permeable membrane having micropores of 50 nm or less, where the gas pressure in the first and second spaces is adjusted to be equal, allowing carbon dioxide to permeate from the first space to the second space and oxygen to permeate back
Data Source
AI summary
An air purifying system includes: a carbon dioxide remover including first and second spaces partitioned by a gas permeable membrane with 50 nm or less diameter micropores; a feed passage leading to-be-purified air from a room to the first space; a supply passage supplying clean gas having lower carbon dioxide and higher oxygen concentrations than the to-be-purified air to the second space; a discharge passage discharging, from the second space, mixed gas; a return passage leading purified air from the first space into the room, the purified air resulting from removing carbon dioxide from the to-be-purified air; and adjusting equipment adjusting a gas pressure in the first and second spaces to be substantially equal to each other. The to-be-purified air flows in the first space along a surface of the gas permeable membrane, and the clean gas flows in the second space along a surface of the gas permeable membrane.