Cryogenic Pressure Control via Heated Conduits
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Solution Overview
Problem
Existing systems for storing cryogenic fluids face challenges in maintaining pressure within predetermined values without venting, and are prone to freezing issues due to the circulation of liquefied gases at cryogenic temperatures through system components.
Innovation Solution
A pressure control system that includes a storage tank with conduits for delivering liquefied gas and vapor to a use device, equipped with heaters and flow controllers actuated by a pressure sensor to maintain pressure within set limits, preventing freezing by warming the fluids before they circulate through the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If liquefied gas is circulated through delivery lines to the use device, then the use device receives cryogenic fuel, but the valves and components in the delivery lines freeze due to exposure to cryogenic temperatures
Solution Approach 1:
The delivery system is divided into separate heated and unheated sections. Flow controllers are positioned in heated sections while the liquefied gas storage and vaporization occur in unheated cryogenic sections, allowing each component to operate in its optimal temperature zone
Solution Approach 2:
Heated delivery lines act as an intermediary between the cryogenic storage tank and the use device, allowing the cryogenic fuel to be transported without exposing downstream components to freezing temperatures
2Stress or pressure
If pressure relief venting is used to maintain tank pressure, then pressure is controlled, but fluid is lost and not delivered to the use device
Solution Approach 1:
Pressure sensors continuously monitor tank pressure and provide feedback to the control system, which automatically adjusts flow controller positions to maintain pressure within predetermined limits, eliminating the need for relief venting
Solution Approach 2:
The system changes the operational parameters of flow controllers based on real-time pressure conditions, adjusting their opening positions to regulate pressure while directing all fluid toward the use device rather than venting
3Stress or pressure
If flow controllers are placed in unheated sections to maintain pressure control, then pressure regulation is achieved, but the flow controllers freeze due to exposure to cryogenic temperatures
Solution Approach 1:
The system separates flow control functions from cryogenic temperature zones by positioning flow controllers in heated delivery lines while maintaining pressure control capabilities through automated adjustment mechanisms
Solution Approach 2:
Heated delivery lines serve as an intermediary zone that allows flow controllers to regulate cryogenic fluid flow without being exposed to freezing temperatures, protecting the controllers from damage
4Ease of operation
If predetermined pressure settings are fixed in the system, then pressure control is simplified, but the system cannot adapt to different operating conditions or user requirements
Solution Approach 1:
The system transitions from fixed predetermined pressure settings to dynamic, adjustable pressure control where users can modify pressure limits through the interface, and the control system automatically adapts its operation to maintain the new settings
Solution Approach 2:
The pressure control system is designed to handle multiple operating conditions and user preferences through a single adjustable interface, making the system versatile enough to adapt to different fuel types, delivery rates, and operational requirements
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
The system effectively maintains pressure within predetermined values, preventing the freezing of components and allowing for adjustable pressure settings, thereby enhancing the efficiency and reliability of cryogenic fluid delivery.
Implementation Method 1
a heater operable to vaporize the liquefied gas before it is delivered to the use device
Implementation Method 2
Each of these flow controllers is independently actuated to control the pressure inside the tank
Implementation Method 3
actuated by a pressure sensor to maintain pressure within set limits
Data Source
AI summary
A pressure control system comprises separate conduits for supplying liquefied gas and vapor from a cryogen space defined by a cryogenic storage tank. A first conduit can deliver liquefied gas to a use device through a heater and then a first flow controller. A second conduit can deliver vapor to the use device with flow therethrough controlled by a second flow controller. The first flow controller is not exposed to liquefied gas at cryogenic temperatures because it is located downstream from the heater. For automatic operation a pressure sensor measures pressure inside the cryogen space and the first and second flow controllers are independently operable to maintain the pressure inside the cryogen space within a predetermined range. In a preferred embodiment the liquefied gas is a combustible fuel that is consumed by an internal combustion engine, which is the use device.