Cryogenic Pump Control for Thermal Shock Reduction
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Solution Overview
Problem
Cryogenic gas delivery systems face challenges with thermal shock, freezing of components, and wide temperature cycling, which can lead to permanent damage and degraded performance due to the cryogenic temperatures and pressure differences.
Innovation Solution
A method and system that control the pump operation to maintain the process fluid temperature above a predetermined threshold by temporarily suspending and restarting the pump based on pressure and temperature conditions, using a controller to manage the heat exchange fluid and ensure the process fluid is not cooled below a certain temperature, thereby reducing thermal shock and extending component lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pump operates continuously to deliver cryogenic gas, then the gas delivery rate is maintained, but thermal shock and freezing of components occur due to cryogenic temperatures
Solution Approach 1:
The pump operates in periodic cycles rather than continuously. The controller suspends pump operation when the process fluid temperature drops below a threshold temperature, allowing the system to recover from thermal shock conditions while maintaining overall productivity through controlled intermittent operation.
Solution Approach 2:
The controller monitors the process fluid temperature and suspends pump operation in advance before severe thermal shock or freezing occurs. By detecting when the temperature approaches critical levels and preemptively stopping the pump, the system prevents damage to components while maintaining gas delivery during safe temperature ranges.
2Stress or pressure
If the pump operates at high pressure to meet delivery requirements, then the gas delivery pressure is sufficient, but the temperature of the process fluid drops below the threshold temperature
Solution Approach 1:
The controller continuously monitors both the process fluid temperature and pressure, and uses this feedback to determine when to suspend or resume pump operation. When temperature drops below the threshold during high-pressure operation, the controller suspends the pump, creating a feedback control mechanism that balances pressure delivery requirements with temperature protection.
Solution Approach 2:
The system dynamically adjusts pump operation based on real-time temperature and pressure conditions. Rather than operating at fixed high pressure continuously, the pump's operational state (on/off) is dynamically controlled to maintain pressure when temperatures are safe and to prevent excessive pressure-induced cooling when temperatures approach critical levels.
3Duration of action of stationary object
If the pump is suspended to prevent thermal shock, then component lifespan is extended, but the gas delivery is interrupted
Solution Approach 1:
The pump is suspended only partially and temporarily when necessary to protect components, rather than being stopped completely or continuously. The suspension is applied selectively based on temperature conditions, extending component lifespan while minimizing delivery interruptions by resuming operation as soon as temperature conditions improve.
Solution Approach 2:
The system uses its own process fluid and operating conditions to regulate itself. The controller monitors the process fluid temperature and automatically suspends/resumes pump operation based on these conditions, allowing the system to self-regulate and protect its own components without external intervention while maintaining gas delivery during safe operating conditions.
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 reduces thermal shock and freezing issues, maintaining system performance and extending the lifecycle of components by ensuring the process fluid remains above a critical temperature, thus preventing damage from extreme temperature fluctuations.
Implementation Method 1
transferring heat from a heat exchange fluid to the process fluid to convert the process fluid from a liquefied form to the gaseous phase
Implementation Method 2
transferring heat from a heat exchange fluid to the process fluid to convert the process fluid from a liquefied form to the gaseous phase
Data Source
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AI summary
A system and method pumps process fluid from a cryogenic storage vessel to a vaporizer, and delivers the fluid as a pressurized gas. The method includes measuring process fluid temperature after the process fluid exits the vaporizer, temporarily suspending operation of the pump when the process fluid temperature is below a threshold temperature, and restarting a suspended pump if at least one predefined enabling condition is satisfied and process fluid pressure is less than a high pressure threshold. The system comprises components that cooperate with one another to execute the method, including a storage vessel, a pump, a vaporizer, a conduit for delivering a pressurized gas from the vaporizer to the end user, a pressure sensor and a temperature sensor for measuring process fluid properties within the conduit, and a controller for commanding operation of the pump responsive to temperature and pressure measurements.