JT Valve Control for Stable Refrigerant Tank Level in Gas Liquefaction
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Solution Overview
Problem
The existing raw material gas liquefying devices face challenges in stabilizing the liquid level in the liquefied refrigerant storage tank due to changes in liquefaction yield caused by variations in entrance temperature or pressure at the Joule-Thomson valve, leading to cycle balance disorders that are difficult to restore.
Innovation Solution
A raw material gas liquefying device with a feed line and refrigerant circulation line that includes temperature and liquid level sensors, allowing the controller to adjust the opening rate of the Joule-Thomson valve to maintain a predetermined liquid level and temperature, ensuring a stable cycle balance by prioritizing liquid level control when it's outside the range and temperature control when it's within the range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the opening rate of the Joule-Thomson valve is adjusted to control temperature, then the temperature control precision is improved, but the liquid level stability deteriorates
Solution Approach 1:
The control method dynamically switches between temperature control mode and liquid level control mode based on the current liquid level status. When liquid level is within the allowable range, temperature control is active; when liquid level exceeds the range, liquid level control takes priority. This dynamic switching resolves the contradiction by adapting the control objective to the current system state.
Solution Approach 2:
The invention changes the controlled parameter from temperature to liquid level when the liquid level exceeds the allowable range. This parameter switching allows the system to prioritize liquid level stability when needed, while maintaining temperature control precision when conditions permit.
2Stability of the object's composition
If the opening rate of the Joule-Thomson valve is adjusted to control liquid level, then the liquid level stability is improved, but the temperature control precision deteriorates
Solution Approach 1:
The control method dynamically switches between temperature control mode and liquid level control mode based on the current liquid level status. When liquid level is within the allowable range, temperature control is active; when liquid level exceeds the range, liquid level control takes priority. This dynamic switching resolves the contradiction by adapting the control objective to the current system state.
Solution Approach 2:
The invention changes the controlled parameter from temperature to liquid level when the liquid level exceeds the allowable range. This parameter switching allows the system to prioritize liquid level stability when needed, while maintaining temperature control precision when conditions permit.
3Stability of the object's composition
If the Joule-Thomson valve opening rate is manipulated for liquid level control, then the liquid level is stabilized, but the temperature may deviate from the set value
Solution Approach 1:
The control method dynamically switches between temperature control mode and liquid level control mode based on the current liquid level status. When liquid level is within the allowable range, temperature control is active; when liquid level exceeds the range, liquid level control takes priority. This dynamic switching resolves the contradiction by adapting the control objective to the current system state.
Solution Approach 2:
The invention changes the controlled parameter from temperature to liquid level when the liquid level exceeds the allowable range. This parameter switching allows the system to prioritize liquid level stability when needed, while maintaining temperature control precision when conditions permit.
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 stabilizes the liquid level and temperature in the liquefied refrigerant storage tank, maintaining a good cycle balance and ensuring stable production of liquefied raw material gas by effectively distributing cryogenic energy.
Implementation Method 1
the raw material gas is cooled by the heat exchangers 81 to 86 and the cooler 88 while flowing through them, and is liquefied by Joule-Thomson (isenthalpic) expansion at the feed system JT valve 16
Implementation Method 2
heat exchangers 81 to 86 which exchange heat between the raw material gas in the feed line 1 and the refrigerant in the refrigerant circulation line 3
Implementation Method 3
the raw material gas which has been compressed (whose pressure has been increased) by a compressor or the like (not shown) and has a high pressure
Data Source
AI summary
A raw material gas liquefying device includes a feed line; a refrigerant circulation line; and a controller. In a refrigerant liquefaction route, a refrigerant flows through a compressor, a heat exchanger, a circulation system JT valve, a liquefied refrigerant storage tank, and the heat exchanger, and returns to the compressor. In a cryogenic energy generation route, the refrigerant flows through the compressor, the heat exchanger, an expansion unit, and the heat exchanger, and returns to the compressor. The controller determines if a refrigerant storage tank liquid level is within an allowable range, manipulates a feed system JT valve opening rate to control refrigerant temperature at the high-temperature-side refrigerant flow path exit side of the heat exchanger, and manipulates the opening rate of the feed system JT valve to control the refrigerant storage tank liquid level so that the refrigerant storage tank liquid level falls into the predetermined allowable range.