Flash Vaporization Sampling for Online Fluid Mixture Detection
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Solution Overview
Problem
Conventional off-line detection methods for fluid mixtures from high-temperature and high-pressure reactors result in errors due to cooling delays, gas-dissolved-in-liquid issues, and evaporation losses, leading to inaccurate component analysis.
Innovation Solution
A system and method involving a pipeline assembly with valves and a vacuum pump, alternating valve operation, and heating elements to flash the fluid mixture into a gas state for direct injection into a gas chromatograph, minimizing errors through rapid pressure changes and temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If off-line detection with cooling depressurization is used, then the detection system is simple, but measurement errors occur due to cooling delays and component changes
Solution Approach 1:
The system performs preliminary flash vaporization of the fluid mixture in a controlled manner before injection into the gas chromatograph. By pre-flashing the sample under controlled conditions and then rapidly injecting it into the heated GC system, the method eliminates cooling delays and prevents component changes during the detection process, thereby improving measurement precision without significantly increasing system complexity
Solution Approach 2:
The invention changes the temperature and pressure parameters during the detection process. The gas chromatograph is maintained at an elevated temperature (e.g., 150-300°C) and the system transitions from liquid phase to gas phase through controlled heating and pressure reduction. This parameter change ensures that components remain in a stable gaseous state throughout detection, preventing condensation and measurement errors
2Measurement precision
If rapid flash vaporization is implemented, then gas dissolution errors are prevented, but system complexity increases due to vacuum pump and valve requirements
Solution Approach 1:
The invention utilizes phase transition from liquid to gas through flash vaporization. By rapidly heating the fluid mixture above its boiling point and immediately injecting it into the heated gas chromatograph system, the liquid phase components instantly vaporize. This rapid phase transition prevents gas components from dissolving in liquid components, thereby improving gas yield measurement accuracy
Solution Approach 2:
The system employs periodic opening and closing of the injection valve synchronized with the vacuum pump operation. The valve opens briefly to allow sample injection when the GC system is under vacuum, then closes to maintain the vacuum state. This periodic action enables continuous sampling while preventing backflow and maintaining system integrity, managing complexity through rhythmic operation rather than complex continuous control
3Measurement precision
If online detection is used, then cooling delay errors are eliminated, but the system requires more complex equipment and operation
Solution Approach 1:
The system maintains continuous operation by keeping the gas chromatograph heated and ready, with the vacuum pump continuously maintaining negative pressure in the detection system. The injection valve operates continuously in a periodic manner, allowing uninterrupted sampling and detection. This continuous operation eliminates cooling delays between samples and maintains components in a stable gaseous state throughout the process, improving conversion rate accuracy while automating operations to reduce manual intervention
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 online detection of fluid mixtures with reduced errors by preventing gas dissolution in liquids and evaporation, ensuring accurate analysis of components with different boiling points.
Implementation Method 1
enabling the fluid mixture to enter the first pipeline for flashing into a gas mixture
Implementation Method 2
heating respective surfaces of the first valve, the pipeline assembly, the gas chromatograph and the second valve by the heating element to a set preheating temperature
Data Source
AI summary
A system and method for detecting a fluid mixture are provided. The system includes a pipeline assembly, a first valve, a gas chromatograph and a vacuum pump. The pipeline assembly includes a first pipeline and a second pipeline. The first valve is connected to the first pipeline and controls a flow of the fluid mixture obtained from a reaction in a reactor. The gas chromatograph is provided with a sample injection end and a sample output end, where the sample injection end is connected to an end of the first pipeline away from the first valve; and the sample output end is connected to the second pipeline. The vacuum pump is connected to an end of the second pipeline away from the gas chromatograph.