UV Oxidation Control in Pure Water Production Under Flow Fluctuation
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Solution Overview
Problem
Conventional ultrapure water production devices face issues with increased hydrogen peroxide generation and dissolved oxygen levels when the water production volume fluctuates, leading to a failure in maintaining the required DO levels due to over-irradiation of ultraviolet rays in the UV oxidation device.
Innovation Solution
A pure water production device with a detection means, such as a flow meter, H2O2 meter, dissolved hydrogen meter, or dissolved oxygen meter, is used to monitor downstream conditions, and a control means adjusts the ultraviolet rays based on these measurements to maintain optimal irradiation levels, even with fluctuations in water volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the water production volume is increased or decreased in response to water demand, then energy efficiency is improved, but the concentration of hydrogen peroxide increases when flow rate decreases
Solution Approach 1:
The ultraviolet ray irradiation amount is made dynamically adjustable based on the flow rate of water. The system transitions from fixed irradiation to variable irradiation that adapts to changing water production volumes, preventing excessive hydrogen peroxide generation during low-flow operation while maintaining effective TOC decomposition during high-flow operation.
Solution Approach 2:
The control system monitors the flow rate of water and uses this feedback to automatically adjust the ultraviolet ray irradiation amount. When flow rate decreases, the system reduces irradiation intensity to match the lower water volume, thereby suppressing hydrogen peroxide concentration increase while still achieving adequate treatment.
2Manufacturing precision
If the amount of ultraviolet rays is increased to decompose TOC, then TOC decomposition is improved, but hydrogen peroxide generation increases
Solution Approach 1:
The system changes the irradiation parameter (ultraviolet ray amount) based on operating conditions. By adjusting irradiation intensity to match actual water flow and TOC load, the system achieves effective TOC decomposition without generating excessive hydrogen peroxide, optimizing the balance between treatment effectiveness and harmful byproduct formation.
3Loss of energy
If the water production volume is decreased to match demand, then energy consumption is reduced, but dissolved oxygen levels increase due to over-irradiation
Solution Approach 1:
The ultraviolet irradiation system dynamically adjusts its output based on water production volume. During low-production periods, the reduced irradiation amount prevents over-oxidation that would otherwise generate excessive dissolved oxygen, while still maintaining sufficient treatment capability.
Solution Approach 2:
The control system uses flow rate feedback to regulate ultraviolet irradiation intensity. This feedback mechanism ensures that irradiation is proportional to actual water treatment needs, preventing dissolved oxygen accumulation during low-flow operation while maintaining energy efficiency.
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 effectively suppresses hydrogen peroxide generation and maintains dissolved oxygen levels within the required limits, ensuring stable ultrapure water production despite variations in water demand.
Implementation Method 1
an ultraviolet oxidation device 13 for treating this primary pure water W1, a platinum group metal catalyst resin tower 25, a membrane degassing device 26... the ultraviolet oxidation device 24 oxidizes and decomposes trace amounts of organic substances (TOC components) contained in the primary pure water W1 by ultraviolet rays
Implementation Method 2
it is known that hydrogen peroxide (H2O2) is generated by the irradiation of ultraviolet rays
Implementation Method 3
dissolved gases such as DO (dissolved oxygen) that have been mixed in are removed by the downstream membrane degassing device 26
Implementation Method 4
by treating through the reverse osmosis membrane device 27 and the non-regenerative ion exchange device 28, residual carbonate ions, organic acids, anionic substances, as well as metal ions and cationic substances are removed
Implementation Method 5
a non-regenerative mixed bed ion exchange device 28... metal ions and cationic substances are removed
Data Source
AI summary
Provided is a pure water production device including an ultraviolet oxidation device for treating TOC components in water to be treated, in which an amount of water to be treated increases or decreases by 5 flow % or more with respect to a set value, and the pure water production device includes: a detection means for detecting an index directly or indirectly related to a concentration of H2O2 downstream or upstream of the ultraviolet oxidation device; and a control means for controlling an amount of ultraviolet rays in the ultraviolet oxidation device based on a detection value of the detection means.