Electrolytic Halogen Disinfectant Production with Scale Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing microbiocidally active solutions through electrolysis of brines often result in the formation of undesirable compounds like trichloramine and dichloramine, which are highly reactive and have strong odors, and can lead to the evolution of hazardous chlorine gas, as well as scale formation in electrolytic cells, causing operational challenges and safety hazards.
Innovation Solution
The method involves adding a halogen stabilizing compound, such as sulfamic acid, to the brine before electrolysis to suppress the formation of trichloramine and dichloramine, maintaining a low pH to prevent scale formation, and using buffering agents to regulate pH and minimize free halogen concentration, while also reversing the polarity of the electrolytic cell to remove scales, thereby producing a stabilized halogen-based disinfectant solution that is acidic and non-volatile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electrolysis of brine is performed to produce microbiocidally active solution, then halogen-based disinfectant is generated, but trichloramine and dichloramine are formed which have strong odors and are highly reactive
Solution Approach 1:
A halogen stabilizing compound is introduced as an intermediary substance that reacts with free halogen to form stabilized halogen compounds. This mediator prevents the direct reaction between halogen and ammonia that would produce harmful chloramines, while still maintaining microbiocidal activity. The stabilizing compound acts as a buffer that controls the chemical reactions in the solution.
Solution Approach 2:
The pH of the brine solution is adjusted to a low range (less than 7, preferably less than 5 or 3) before electrolysis. This parameter change suppresses the formation of chloramines by shifting the chemical equilibrium and reducing the reactivity of ammonia with halogen. The acidic conditions also help stabilize the halogen compounds and prevent unwanted side reactions.
2Productivity
If electrolysis is performed to generate halogen-based disinfectant, then microbiocidal activity is achieved, but hazardous chlorine gas evolves
Solution Approach 1:
The pH is lowered below 7 (preferably below 5 or 3) to shift the equilibrium of halogen species. At low pH, hypohalous acids dominate over hypohalite ions, and the solubility of halogen gases increases. This parameter change reduces the evolution of hazardous chlorine gas while maintaining the microbiocidal effectiveness of the solution.
Solution Approach 2:
The halogen stabilizing compound serves as an intermediary that binds free halogen, reducing its volatility and tendency to escape as gas. This mediator keeps the halogen in solution in a stabilized form, preventing hazardous gas evolution while maintaining the active disinfectant properties.
3Productivity
If electrolysis operates continuously to produce disinfectant solution, then steady supply is achieved, but scale forms in electrolytic cell causing operational challenges
Solution Approach 1:
The pH is maintained in an acidic range (less than 7, preferably less than 5 or 3) which prevents scale formation. At low pH, calcium and magnesium ions remain in solution as soluble salts rather than precipitating as carbonates or hydroxides. This parameter control allows continuous operation without scale buildup on electrodes or cell surfaces.
Solution Approach 2:
The brine is pre-treated by adjusting pH and adding halogen stabilizing compounds before electrolysis begins. This preliminary action prepares the solution to resist scale formation during the electrolysis process, enabling continuous operation without interruption for cleaning or maintenance.
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 prevents the formation of volatile chloramines and chlorine gas, reduces scale buildup, and produces a stable, effective microbiocidal solution that is safer to handle and more efficient in operation, with improved microbial inactivation efficacy.
Implementation Method 1
electrolyzing the brine in an electrolytic cell, thereby producing a microbiocidally active solution comprising a stabilized halogen compound
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Disclosed in the present invention are methods and apparatuses for the electrochemical conversion of halide ion containing brines into halogen based disinfection solutions while the impact of scale formation on electrochemical system operations. This is accomplished by controllably modifying the brine with one or more of halide ions, a halogen stabilization compound, an acid component, or a buffering component. These chemical modifications of the brine allow for the production of stabilized 10 halogen solutions, which can then be used as disinfectants. The present invention is especially useful in the production of halogen-based biocides from flowback or produced waters resulting from oil and gas production, but can be applied to any halide ion containing water stream, including reject water from reverse osmosis filtration processes or ocean water, that contains ammonia.