Photocatalytic Air Purifier Humidity Control for Faster PCO
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for controlling humidity in photocatalytic oxidation (PCO) reactions are ineffective, leading to incomplete oxidation and slow reaction rates due to suboptimal humidity levels, which result in toxic byproducts and inefficient pollutant degradation.
Innovation Solution
A method and device that split air flow into two streams, where a smaller stream is adjusted to achieve the desired humidity for the photocatalyst by using a hygrometer to monitor and control humidity levels, ensuring the photocatalyst operates within an optimal humidity range without significantly altering the overall air humidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the humidity of air flow is controlled to adjust photocatalyst humidity, then the PCO reaction rate is improved, but the device complexity increases due to additional humidity control mechanisms
Solution Approach 1:
The air flow is divided into two separate streams: a first air stream that passes through the photocatalyst to adjust its humidity, and a second air stream that is discharged. This segmentation allows humidity control to be applied selectively to only the portion of air flow that contacts the photocatalyst, rather than controlling the entire air flow system, thereby reducing overall device complexity while maintaining improved reaction rates.
Solution Approach 2:
Humidity control is applied locally to the first air stream that directly interacts with the photocatalyst surface, rather than uniformly to the entire air flow. This localized approach ensures that the photocatalyst operates at optimal humidity for maximum reaction rate, while the second air stream remains unaffected and can be discharged without additional processing.
2Reliability
If a portion of air flow is used to adjust photocatalyst humidity, then the reaction completeness is improved, but the loss of time for humidity adjustment occurs
Solution Approach 1:
The humidity of the first air stream is adjusted before it contacts the photocatalyst, ensuring that the photocatalyst surface is pre-conditioned with optimal humidity levels. This preliminary humidity adjustment prevents incomplete oxidation reactions from occurring, ensuring reaction completeness is achieved before the main PCO process begins, thereby eliminating delays associated with mid-process humidity corrections.
3Ease of operation
If the humidity of photocatalyst is not maintained optimally, then the device operation is simpler, but toxic byproducts are generated
Solution Approach 1:
A hygrometer is integrated into the system to continuously monitor the humidity of the photocatalyst and provide feedback to a control unit. The control unit adjusts the humidity of the first air stream based on this feedback to maintain optimal humidity levels on the photocatalyst surface. This automated feedback mechanism ensures that the photocatalyst operates within the optimal humidity range (1000-4000 ppmv), preventing the formation of toxic byproducts while minimizing manual intervention and maintaining ease of operation.
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 allows for effective PCO reactions by maintaining the photocatalyst at an optimal humidity, enhancing reaction rates and minimizing toxic byproducts, while keeping the discharged air humidity unchanged.
Implementation Method 1
When the photocatalyst is irradiated by UV light, electron in the valence band (VB) is excited to a vacant conduction band (CB), producing a positive hole (h+)
Implementation Method 2
PCO reaction can degrade various VOC pollutants into innocuous products such as CO2 and H2O
Implementation Method 3
when the humidity is too high, water vapor competes with TiO2 for adsorption sites
Implementation Method 4
The positive holes (h+) will react with the adsorbed water molecules (H2O) to generate hydroxyl radicals (OH)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention relates to a method and a device for performing PCO reaction. The method comprises steps of: guiding an air flow into a PCO reactor, which PCO reactor contains photocatalyst for the PCO reaction; splitting the air flow into a first stream and a second stream, wherein quantity of the first stream being less than quantity of the second stream; obtaining the humidity of the photocatalyst; controlling the humidity of the first stream according to the obtained humidity of the photocatalyst; adjusting the humidity of the photocatalyst by guiding the first stream to the photocatalyst; guiding the second stream through the photocatalyst; and illuminating the photocatalyst with light. By controlling the humidity of air passing through the photocatalyst oxidation based on the obtained humidity of the photocatalyst, PCO reaction can be performed effectively.