Photometric Amine Determination via pH-Buffered Colorimetry
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for determining film-forming amine concentrations in nuclear power plant water-steam cycles are either time-consuming, lack accuracy, or require sensitive pH control, making them unsuitable for real-time monitoring and reliable corrosion prevention.
Innovation Solution
A method involving the formation of a colored complex with a reagent, such as Phloxine B, using a buffer solution with a weak acid (pKa ≥ 4.5) and strong acid (pKa ≤ 1), where the pH of the sample solution is adjusted to match the diluted buffer solution's pH, allowing for precise photometric measurement and continuous monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional photometric methods using rose bengal or methyl orange are used to determine amine concentrations, then color formation occurs for measurement, but the methods require sensitive pH control (pH 2.3-3.3) and are very pH sensitive, leading to unreliable results
Solution Approach 1:
The patent changes the pH parameter range from the conventional sensitive range (2.3-3.3) to a more stable range (4.0-6.0), specifically optimizing to pH 4.5-5.5. This parameter change makes the measurement less sensitive to pH fluctuations while maintaining accurate color formation for amine detection, resolving the contradiction between measurement precision and ease of operation.
Solution Approach 2:
The patent introduces a buffer solution as an intermediary substance to stabilize the pH at the optimized range (4.5-5.5). The buffer acts as a mediator between the amine sample and the color reagent, ensuring consistent pH conditions without requiring sensitive manual control, thereby improving both measurement reliability and operational ease.
2Reliability
If film-forming amine concentration is not monitored accurately, then corrosion protection may be insufficient, but overdosing of amines causes clogging of filters and undesired effects
Solution Approach 1:
The patent implements a feedback mechanism by enabling continuous or periodic monitoring of amine concentrations in the water-steam cycle. The photometric method provides real-time concentration data, allowing the system to adjust amine dosing to maintain optimal protection levels and prevent both under-dosing (insufficient corrosion protection) and over-dosing (filter clogging).
Solution Approach 2:
The patent replaces manual sampling and laboratory analysis with an automated photometric measurement system. This substitution enables continuous monitoring without mechanical intervention, providing reliable real-time data for corrosion protection while preventing amine overdose through automated control.
3Measurement precision
If conventional amine determination methods are used, then color formation can be achieved, but the sample preparation is time-consuming and the methods are not suitable for on-line monitoring
Solution Approach 1:
The patent performs preliminary action by pre-adjusting the pH of the buffer solution to the optimized range (4.5-5.5) before mixing with the amine sample. This preliminary pH adjustment eliminates time-consuming pH adjustments during sample analysis, enabling rapid measurements suitable for on-line monitoring while maintaining measurement precision.
Solution Approach 2:
The patent enables continuous measurement by eliminating time-consuming sample preparation steps. The optimized method allows for continuous or periodic sampling and analysis, maintaining uninterrupted monitoring of amine concentrations in the water-steam cycle, which is essential for both precision and productivity.
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 enhances the accuracy and reproducibility of film-forming amine concentration measurements, preventing side reactions and enabling reliable, on-line monitoring of amine concentrations in industrial processes.
Implementation Method 1
a reagent is added to the liquid to form a colored complex of the amine and the reagent, wherein the colored complex is measured photometrical
Implementation Method 2
measuring an initial absorbance of said diluted buffer solution containing the reagent
Data Source
Figure 1
Figure 2
AI summary
A photometric method for the determination of a film forming amine in a liquid, comprises the steps of a) providing a buffer solution of a weak acid having a pKa ≥ 4.5 and a strong acid having a pKa ≤ 1; b) diluting an aliquot of the buffer solution with a given volume of water, and determining a pH value of said diluted buffer solution; c) adding a given amount of a reagent to said diluted buffer solution and measuring an initial absorbance of said diluted buffer solution containing the reagent; d) preparing a sample solution by adding a given volume of the liquid containing the film forming amine to an aliquot of the buffer solution and measuring a pH value of the sample solution; e) adjusting the pH value of the sample solution to match with the pH value of the diluted buffer solution by adding a calculated amount of the strong acid; and f) adding a given amount of said reagent to the pH adjusted sample solution to form a colored complex, and measuring the absorbance of the pH adjusted sample solution containing the reagent and the colored complex in a photometer.