Cryogenic Tank Pressure Control via Liquid Circulation

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Solution Overview

Problem

Maintaining constant pressure in cryogenic fluid storage tanks is challenging due to inconsistencies between venting equipment and pressure regulation devices, requiring complex adjustments and often resulting in unsatisfactory pressure control, especially in the lower part of the tank.

Innovation Solution

The tank features an automated pressure regulation system where the pressurization pipe valve maintains a minimum pressure by circulating reheated liquid and includes a vent regulator to manage pressure above a maximum value, using sensors to control electrically actuated valves and ensure consistent pressure management through integrated valves for pressurization, vaporized gas withdrawal, and filling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate venting equipment and pressure regulation devices are used, then pressure control functions are provided, but the system complexity increases and pressure regulation becomes inconsistent

Engineering Contradiction:
Improvepressure control reliabilityVSAvoidpressure regulation system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple pressure control functions (venting, pressure regulation, and liquid circulation control) into a single integrated pressure control device. This device includes a regulator valve for pressure maintenance, a venting valve for overpressure relief, and a circulation valve for liquid recirculation, all controlled by a single actuator that responds to pressure sensor signals. This integration eliminates the need for separate control mechanisms, reducing system complexity while maintaining reliable pressure control throughout the tank.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated pressure control device performs multiple functions simultaneously: it regulates pressure to maintain minimum levels, vents excess pressure to prevent overpressure, and controls liquid circulation through the heater. The single actuator can position the valve elements to achieve different control functions based on real-time pressure conditions, making the device universal for all pressure management needs in the cryogenic storage tank.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If complex settings are used for pressure regulation, then pressure control capability is improved, but the ease of operation decreases

Engineering Contradiction:
Improvepressure regulation capabilityVSAvoidpressure control operation simplicity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The pressure control system operates autonomously without requiring manual intervention or complex settings. Pressure sensors continuously monitor the tank pressure and automatically signal the actuator to adjust the valve positions. The system self-regulates by maintaining pressure above the minimum threshold while preventing overpressure conditions, eliminating the need for operators to make complex adjustments or monitor multiple separate control devices.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system incorporates continuous pressure feedback through sensors that monitor the actual pressure conditions in the tank. This feedback is used by the actuator to automatically adjust the valve positions in real-time, creating a closed-loop control system that maintains pressure within the desired range without requiring manual intervention or complex operator decisions.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If separate devices are used for venting and pressure regulation, then specific functions are achieved, but the overall pressure stability deteriorates

Engineering Contradiction:
Improvepressure control function coverageVSAvoidpressure stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent merges venting, pressure regulation, and liquid circulation control into a single integrated device with coordinated valve elements. This ensures that pressure control actions are synchronized and consistent, preventing the instability that arises from conflicting settings of separate devices. The integrated design maintains pressure stability by ensuring that all control functions work together harmoniously based on real-time pressure conditions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated pressure control device dynamically adjusts the opening positions of its multiple valve elements based on real-time pressure feedback. The actuator can simultaneously or sequentially activate different valve elements depending on whether pressure needs to be maintained, reduced, or stabilized. This dynamic coordination of multiple functions within a single device ensures pressure stability while maintaining the versatility to handle various pressure control scenarios.

Inventive Principle:
Principle #15Dynamics

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 solution provides stable and automatic pressure regulation within the tank, preventing overpressure and ensuring consistent operation by integrating sensors and actuated valves to manage pressure across the tank's envelope, enhancing safety and efficiency.

Implementation Method 1

a heater, in particular a vaporization heat exchanger

Methodology Applied
Scientific EffectVaporization: Evaporation

Implementation Method 2

a heater, in particular a vaporization heat exchanger

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 3

a set of sensor(s) measuring the pressure in the first casing

Methodology Applied
Scientific EffectPressure sensing:

Implementation Method 4

said control valve comprises at least one movable element closing or opening a passage for the fluid in the pressurization pipe, said movable element being opened or closed according to the pressure difference

Methodology Applied
Scientific EffectPressure differential control: Pressure Gradient

Implementation Method 5

the vent regulator comprises a pneumatic valve or an electrically controlled valve configured to control the opening and closing of the valve towards the atmosphere as a function of the pressure measured

Methodology Applied
Scientific EffectPressure regulation:

Data Source

PatentEP3891431B1Storage vessel for cryogenic fluid
Publication Date: 2024.08.28 LAIR LIQUIDE SA POUR LETUDE & LEXPLOITATION DES PROCEDES GEORGES CLAUDE
  • EP3891431B1 patent drawingFigure 1
  • EP3891431B1 patent drawingFigure 2~3
  • EP3891431B1 patent drawingFigure 4~5

AI summary

The invention relates to a tank for storing a two-phase cryogenic mixture of liquid and gas, comprising a first casing (1), at least one drawing pipe (5, 7), a tank filling circuit, the tank comprising a sensor assembly (12) measuring the pressure in the first casing (1), the tank comprising a pipe (21) for pressurizing the internal casing (1), comprising an upstream end connected to the lower end of the first casing (1) and a downstream end connected to the upper part of the first casing (1), the pressurization line (21) comprising at least one regulating valve (14) and a heater (13), in particular a vaporization heat exchanger. The invention is characterized in that the regulating valve (14) is configured to automatically maintain the pressure in the first casing (1) at a minimum value by ensuring, when the pressure in the first casing (1) is lower than said first value, a circulation of liquid taken from the first casing (1) in the heater (13) and a re-injection of said heated fluid into the first casing (1).