Cryogenic Liquid Impurity Determination Using Wet-Surface Vaporization
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Solution Overview
Problem
Current methods for determining impurity levels in cryogenic liquids, particularly in systems for separating gases from air, face challenges such as low solubility and equilibrium coefficients, leading to inaccurate measurements and safety risks due to impurity buildup and potential explosions, especially with impurities like propane and carbon dioxide, which require precise concentration and analysis at very low parts per billion levels.
Innovation Solution
A system and method that concentrate impurities in a residual cryogenic liquid before vaporization, utilizing a vessel with vaporization means that create a thermosiphon effect to keep the heating surface wet, preventing excessive vaporization and impurity deposition, allowing for precise measurement of impurities like propane, nitrous oxide, and carbon dioxide without distorting concentration factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complete vaporization of the sample is performed to obtain a gas for analysis, then the impurity proportion can be measured, but impurities build up in the vaporization device distorting measurements
Solution Approach 1:
The patent extracts only a portion of the cryogenic liquid sample for vaporization and analysis, rather than vaporizing the entire sample. This prevents impurity buildup in the vaporization device while still providing sufficient material for accurate measurement of impurity proportions at parts per billion levels.
Solution Approach 2:
The system performs preliminary concentration of impurities in the remaining liquid sample before analysis. By controlling the vaporization process to concentrate impurities in the residual liquid, the system prepares the sample in advance for more accurate detection without requiring complete vaporization that would cause device contamination.
2Measurement precision
If vaporization is performed to concentrate impurities in residual liquid, then measurement sensitivity is improved, but impurities may escape into gas phase distorting concentration factors
Solution Approach 1:
The patent carefully controls vaporization parameters (temperature, pressure, heating rate) to optimize the concentration process. By adjusting these parameters, the system concentrates impurities in the residual liquid while minimizing their escape into the gas phase, maintaining accurate concentration factors for measurement.
3Measurement precision
If gas analyzers are used to measure impurities, then impurity levels can be detected, but the equipment and operational skill requirements are excessive
Solution Approach 1:
The system performs preliminary concentration of impurities in the liquid sample before analysis. This pre-concentration step enhances the sensitivity required for parts per billion detection, allowing the use of less complex gas analyzer equipment while still achieving the necessary measurement precision.
4Reliability
If adsorption processes are used to eliminate heavy hydrocarbons, then safety is improved, but light hydrocarbons and propane remain undetected and can cause explosive situations
Solution Approach 1:
The patent uses an intermediary measurement system that detects light hydrocarbons and propane in the cryogenic liquid before they can accumulate to dangerous levels. This intermediary detection capability complements the existing adsorption processes by providing early warning of potentially explosive conditions.
Solution Approach 2:
The system implements feedback monitoring of light hydrocarbon and propane levels in the cryogenic liquid. By continuously measuring these impurities and providing feedback to the control system, the plant can take corrective action before explosive conditions develop, enhancing overall safety.
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 concentrates impurities in the residual liquid, reducing the amount escaping into the gas phase, preventing impurity buildup and ensuring accurate measurement, thereby enhancing the safety and efficiency of gas separation systems by maintaining acceptable impurity levels and preventing combustion risks.
Implementation Method 1
the vaporization means being capable of producing a thermosiphon effect between the intake duct and the plurality of discharge ducts
Implementation Method 2
vaporization means for vaporizing the initial volume of cryogenic liquid until a volume of residual cryogenic liquid is obtained in which the impurity is concentrated
Data Source
AI summary
The present invention relates to a determination system for determining the content of at least one impurity in a cryogenic liquid, comprising:a vessel capable of receiving an initial volume of the cryogenic liquid,vaporization means for vaporizing the initial volume of cryogenic liquid until a volume of residual cryogenic liquid is obtained in which the impurity is concentrated, the vaporization means being disposed in the lower part of the vessel andmeans for determining the proportion of the impurity in the residual cryogenic liquid,wherein that the vaporization means comprise a heating surface capable of vaporizing the cryogenic liquid, the vaporization means being configured to keep said heating surface wet using the volume of residual cryogenic liquid.