In-situ Chlorine Generation via Carbon Dioxide Injection

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Solution Overview

Problem

Existing chlorination methods for water, particularly in swimming pools and drinking water treatment, face challenges with gaseous chlorine's toxicity and environmental hazards, and the use of solid or dissolved chlorine compounds introduces additional chemicals that can lead to corrosion and pH imbalances, necessitating frequent acid additions.

Innovation Solution

A method involving a chlorine compound that releases gaseous chlorine upon contact with carbon dioxide, allowing for the formation of chlorine gas upstream from the water treatment process, which is then introduced into the water, avoiding direct contact with the chlorine compound and reducing the need for pH-adjusting chemicals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If gaseous chlorine is used for chlorination, then disinfection effectiveness is improved, but safety hazards and environmental risks increase

Engineering Contradiction:
Improvedisinfection effectivenessVSAvoidtoxicity and environmental hazards
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses carbon dioxide as an intermediary substance to generate chlorine in-situ. Instead of directly introducing gaseous chlorine, the system introduces CO2 which reacts with hypochlorite ions in the water to produce chlorine gas locally. This mediator approach maintains disinfection effectiveness while eliminating the need to handle and store hazardous chlorine gas cylinders.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If solid or dissolved chlorine compounds are used for chlorination, then safety and plant complexity are improved, but additional chemicals are introduced into the water

Engineering Contradiction:
Improvesafety hazardsVSAvoidintroduction of additional compounds
Core Design Contradiction:
Object-affected harmful factorsVSLoss of substance

Solution Approach 1:

The patent extracts only the desired chlorine component from the chlorine compound through a chemical reaction with carbon dioxide. The reaction Ca(ClO)2 + CO2 + H2O → CaCO3 + 2HClO releases chlorine in-situ, while the calcium carbonate precipitates out and does not remain in the water. This selective extraction avoids introducing unwanted salts and chemicals into the treated water.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the chemical parameters by using carbon dioxide to trigger the release of chlorine from hypochlorite compounds. By controlling the CO2 introduction, the system activates chlorine generation only when needed, converting stable hypochlorite storage into active chlorine disinfectant on-demand, thereby avoiding continuous presence of additional chemicals.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If additional chemicals are added for pH adjustment, then pH control is improved, but ion load and process complexity increase

Engineering Contradiction:
ImprovepH value controlVSAvoidprocess complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The system achieves self-regulating pH control through the chemistry of the chlorine generation reaction itself. When CO2 is introduced to generate chlorine, it forms carbonic acid which naturally buffers the pH. The reaction produces calcium carbonate precipitate that also helps stabilize pH. This self-service mechanism eliminates the need for separate pH adjustment chemicals and complex dosing systems.

Inventive Principle:
Principle #25Self-service

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 eliminates the introduction of unwanted salts and reduces the complexity of the chlorination process, making it safer and more efficient for small to medium-sized water treatment systems by using inorganic or organic chlorine compounds like magnesium or calcium hypochlorite, which release chlorine when exposed to CO2, thus maintaining optimal pH levels without additional acid additions.

Implementation Method 1

a chlorine compound which liberates gaseous chlorine on contact with carbon dioxide, liberating gaseous chlorine by contacting the chlorine compound with carbon dioxide

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentEP2803640B1Method and system for chlorination of water
Publication Date: 2018.01.31 BWT AG
  • EP2803640B1 patent drawingFigure 1~2

AI summary

A process for chlorinating water is described, in which a chlorine compound (preferably a salt of hypochlorous acid or di-/trichloroisocyanic acid), which releases gaseous chlorine upon contact with carbon dioxide, is provided and brought into contact with carbon dioxide. The chlorine released in this process is added to the water to be chlorinated via the gas injector (16). Furthermore, a device (11) for generating gaseous chlorine and a system (10) comprising such a device (11) are described. A swimming pool (20) with a water basin (21) and such a device (11) and/or such a system (10) is also described.