Ballast Water Dechlorination Using ORP Feedback Control
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Solution Overview
Problem
Shipboard ballast water management systems face challenges in maintaining optimal chlorine concentrations due to variability in nitrogen compounds, leading to excessive oxidizer concentrations that cause corrosion and undesirable disinfection by-product formation, while existing systems fail to effectively regulate biocide levels across different ports and seasons.
Innovation Solution
A ballast water management system that utilizes an electrolytic cell with a power supply to generate chlorine-based biocides, incorporating ORP sensors to regulate the biocide generation and neutralization, ensuring optimal oxidation-reduction potential values and adjusting flow rates to maintain effective disinfection while minimizing corrosion and by-product formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chlorine-based biocides are generated and introduced into ballast water to inhibit biological activity, then disinfection effectiveness is improved, but excessive oxidizer concentration causes corrosion of ship systems and formation of disinfection by-products
Solution Approach 1:
The system employs ORP sensors to continuously monitor the oxidation-reduction potential of ballast water and provides feedback to the controller. The controller adjusts the biocide generation rate based on this feedback, maintaining ORP within a target range (e.g., 200-400 mV) to ensure effective disinfection while preventing excessive oxidizer concentration that would cause corrosion and by-product formation.
Solution Approach 2:
The system dynamically adjusts the ORP parameter within an optimized range (200-400 mV) rather than maintaining a fixed high chlorine concentration. This parameter change approach allows effective disinfection while minimizing corrosion and by-product formation, as the ORP range is sufficient to inhibit biological activity without requiring excessive oxidizer levels.
2Ease of operation
If fixed chlorine output is used in ballast water management systems, then system operation is simplified, but variability in nitrogen compounds across different ports and seasons causes inconsistent disinfection效果和over-chlorination
Solution Approach 1:
The system uses ORP sensors to provide real-time feedback on water conditions, allowing automatic adjustment of biocide generation rates. This feedback mechanism enables the system to adapt to varying nitrogen compound concentrations across different ports and seasons while maintaining consistent disinfection effectiveness, eliminating the need for manual intervention.
Solution Approach 2:
The system transitions from fixed chlorine output to dynamic biocide generation controlled by the controller based on ORP sensor readings. This dynamic operation allows the system to automatically adapt to changing water conditions (nitrogen compound variability) across different ports and seasons, maintaining optimal disinfection without over-chlorination.
3Reliability
If high chlorine concentration is maintained to ensure disinfection, then biological activity inhibition is improved, but corrosion of ballast water pumps, piping, and tanks increases
Solution Approach 1:
The system maintains ORP within an optimized range (200-400 mV) rather than using high chlorine concentrations. This parameter optimization ensures sufficient biological activity inhibition while minimizing corrosion of ballast water pumps, piping, and tanks, as the ORP range is effective for disinfection without requiring excessive oxidizer levels that would accelerate corrosion.
Solution Approach 2:
The ORP sensor provides continuous feedback on the actual oxidation-reduction potential, allowing the controller to adjust biocide generation to maintain ORP within the target range. This prevents excessive chlorine concentration that would cause corrosion while ensuring sufficient levels for biological activity inhibition.
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 effectively manages biocide concentrations, reducing the risk of corrosion and by-product formation, ensuring effective disinfection of ballast water across varying conditions without over-chlorination, thereby protecting ship systems and the environment.
Implementation Method 1
an electrolytic cell with at least one anode and at least one cathode, a power supply disposed to supply direct current through at least one anode and at least one cathode to generate the biocide
Implementation Method 2
incorporating ORP sensors to regulate the biocide generation and neutralization, ensuring optimal oxidation-reduction potential values
Implementation Method 3
a neutralization system configured to introduce a neutralizing agent selected to at least partially neutralize the biocidal activity of the biocide into the discharged ballast water
Data Source
AI summary
Techniques and systems for neutralizing discharge waters from ballast and/or cooling water biocidal treatment and disinfection systems are provided. The systems utilize, inter alia, oxidation reduction potential control to regulate the dechlorination of an electrocatalytically generated biocidal agent to allowable discharge levels in ship buoyancy systems and ship cooling water systems.