Cryogenic Liquid Analyzer Using Partial Vaporization for Trace Impurities
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Solution Overview
Problem
Current methods for analyzing impurities in cryogenic liquids, such as those used in air separation by cryogenic distillation, face challenges in detecting low levels of contaminants like N2O and CO2, which are below 100 ppb, requiring complex apparatus and significant operating skill, and often result in incomplete or inaccurate determination of impurity types and quantities due to prolonged vaporization processes and lack of precise sampling.
Innovation Solution
An apparatus that involves partial vaporization of a known quantity of cryogenic liquid, allowing impurities to concentrate in the liquid phase, followed by direct analysis of the vaporized phase after overheating to ensure complete vaporization and measurement of contaminant content using conventional analyzers capable of detecting concentrations below 1 ppm, with a controlled cycle time to avoid prolonged accumulation and ensure accurate quantification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex apparatus and prolonged vaporization processes are used to detect low levels of impurities, then measurement precision is improved, but device complexity and operational time increase
Solution Approach 1:
The invention changes the concentration parameter by partially vaporizing the liquid oxygen sample, which concentrates the impurities in the remaining liquid phase. This parameter change enables conventional analyzers to detect impurities at levels below 100 ppb without requiring complex specialized apparatus, thus resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
The invention utilizes the phase transition of oxygen from liquid to vapor during controlled partial vaporization. By exploiting the different vaporization characteristics of oxygen and impurities, the method concentrates impurities in the liquid phase while oxygen vaporizes, enabling detection with standard equipment and reducing both device complexity and operational time
2Measurement precision
If prolonged vaporization processes are used to accumulate sufficient impurities for detection, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The invention applies partial vaporization rather than complete vaporization of the liquid oxygen sample. By vaporizing only a controlled portion (enough to concentrate impurities to detectable levels), the method achieves accurate impurity quantification significantly faster than prolonged complete vaporization processes, thus resolving the contradiction between measurement precision and time loss
Solution Approach 2:
The method changes the concentration parameter through controlled partial vaporization, achieving sufficient impurity concentration for accurate detection within a short time frame. This parameter change eliminates the need for prolonged accumulation processes while maintaining measurement precision
3Ease of operation
If conventional analyzers are used for impurity detection, then ease of operation is improved, but measurement precision deteriorates due to detection limits
Solution Approach 1:
The invention changes the concentration parameter by partially vaporizing the liquid oxygen, which concentrates impurities in the remaining liquid phase. This parameter change raises the impurity concentration above the detection limits of conventional analyzers, enabling these simpler devices to achieve the required measurement precision for detecting impurities below 100 ppb
Solution Approach 2:
The invention creates a local concentrated phase of impurities in the remaining liquid after partial vaporization. This local concentration enables conventional analyzers to detect and measure impurities accurately without requiring complex specialized equipment, thus resolving the contradiction between ease of operation and measurement precision
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
Enables rapid and precise measurement of impurity concentrations below 1 ppm, reducing operational complexity and cycle time, while ensuring accurate determination of contaminant content without the need for prolonged accumulation or external sampling, thereby enhancing operational safety and efficiency in cryogenic distillation systems.
Implementation Method 1
a) a partial vaporization of a determined quantity of this liquid is performed
Implementation Method 2
allowing impurities to concentrate in the liquid phase
Implementation Method 3
b) the vaporized phase is then overheated, thus creating a rise in pressure in the vaporization enclosure
Implementation Method 4
The evolution of the pressure measured in the closed enclosure gives the quantity of matter initially present in the liquid or solid phase
Data Source
Figure 1
AI summary
An apparatus for analysing the content of at least one contaminant in a liquid cryogen comprising a cylindrical enclosure (E), an annular enclosure (V) arranged around the cylindrical enclosure, means (1, 3, 5) for dividing a flow of liquid cryogen in two, means for delivering a first part (3) of the liquid cryogen to the cylindrical enclosure, means for delivering a second part (5) of the liquid cryogen to the annular enclosure, a pipe (13) connected to the cylindrical enclosure to allow vaporised liquid to pass through, a pipe (6) connected to the annular enclosure to allow vaporised liquid to pass through, a heater (H) for heating the cylindrical enclosure vessel and means (V1) for stopping the delivery of liquid cryogen to the cylindrical enclosure.