Hydrogen Chloride Production via pH-Controlled Electrolysis
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Solution Overview
Problem
Existing methods for producing high purity hydrogen chloride are complex and inefficient, particularly in removing impurities like hydrogen bromide and carbon dioxide due to their close boiling points with hydrogen chloride, leading to facility complications and reduced production efficiency.
Innovation Solution
Adjusting the pH of an inorganic chloride aqueous solution during electrolysis and controlling the molar ratio and temperature of chlorine and hydrogen reaction to minimize impurity concentrations, followed by dehydration and distillation steps, simplifies the facility and enhances purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If distillation is used to remove impurities from hydrogen chloride, then the hydrogen chloride purity is improved, but impurities like hydrogen bromide and carbon dioxide cannot be effectively removed due to close boiling points
Solution Approach 1:
The patent applies preliminary action by adjusting the pH of the inorganic chloride aqueous solution to 3.1-4.5 before electrolysis. This pre-adjustment ensures that impurities like hydrogen bromide and carbon dioxide are minimized at the source, preventing them from being generated in the first place rather than attempting to remove them later through distillation.
Solution Approach 2:
The patent changes the pH parameter of the electrolyte solution to a specific range (3.1-4.5) and controls the molar ratio of hydrogen to chlorine (1.05-1.20) to optimize the electrolysis process. These parameter changes ensure that the generated hydrogen chloride contains minimal impurities, making subsequent purification easier and more effective.
2Manufacturing precision
If distillation towers or adsorption towers are mounted to purify chlorine and hydrogen in advance, then the hydrogen chloride purity is improved, but the facility complexity increases and production efficiency decreases
Solution Approach 1:
The patent extracts the impurity removal function from the post-electrolysis purification stage and moves it to the pre-electrolysis stage by controlling the pH and composition of the inorganic chloride aqueous solution. This eliminates the need for separate distillation towers or adsorption towers for chlorine and hydrogen purification, simplifying the overall facility while maintaining high purity output.
Solution Approach 2:
The electrolysis system becomes self-service regarding impurity removal by using the pH-adjusted inorganic chloride aqueous solution as both the electrolyte and the purification mechanism. The controlled electrolysis process inherently produces high-purity hydrogen chloride without requiring external complex purification facilities.
3Manufacturing precision
If distillation towers or adsorption towers are mounted to purify chlorine and hydrogen in advance, then the hydrogen chloride purity is improved, but the production efficiency decreases
Solution Approach 1:
By performing pH adjustment and impurity minimization before electrolysis, the patent eliminates the need for time-consuming post-electrolysis distillation or adsorption processes. This preliminary action streamlines the production flow and increases overall production efficiency while maintaining high purity standards.
Solution Approach 2:
The optimized electrolysis process with controlled pH and molar ratios enables continuous production of high-purity hydrogen chloride without interruption for complex purification cycles. The process maintains continuous useful action throughout, improving productivity while ensuring purity requirements are met.
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 method efficiently produces hydrogen chloride with impurity concentrations below 0.5 ppm, achieving a purity of 99.999 mass% or more with a simplified facility, suitable for semiconductor and thin film transistor processes.
Implementation Method 1
an electrolysis step of obtaining the chlorine and the hydrogen by electrolyzing an inorganic chloride aqueous solution
Implementation Method 2
a dehydration step of dehydrating the crude hydrogen chloride obtained in the reaction step
Implementation Method 3
a distillation step of compressing and liquefying the dehydrated crude hydrogen chloride obtained in the dehydration step
Implementation Method 4
purifying the liquid crude hydrogen chloride by distillation
Data Source
Figure 1
AI summary
Provided is a method for producing a hydrogen chloride that is capable of efficiently producing a hydrogen chloride with a simple facility. The hydrogen chloride is produced by a method including obtaining chlorine and hydrogen by electrolyzing an inorganic chloride aqueous solution of which a pH is 3 to 5, obtaining a crude hydrogen chloride by reacting the chlorine and the hydrogen obtained in the electrolyzing at 1000°C to 1500°C with a use of an excess quantity of the hydrogen with respect to the chlorine in a molar ratio, dehydrating the crude hydrogen chloride obtained in the reacting, and compressing and liquefying the dehydrated crude hydrogen chloride obtained in the dehydrating, and purifying the liquid crude hydrogen chloride by distillation.