Insulated chamber and method for flushing such a chamber
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Solution Overview
Problem
Existing insulated chambers used in air separation units, particularly those employing solid insulation at subambient or cryogenic temperatures, face inefficiencies in nitrogen distribution, leading to inadequate thermal performance, risk of moisture ingress, and potential ignition hazards due to uneven gas flow and incomplete flushing.
Innovation Solution
The implementation of a nitrogen flushing system that injects gas containing at least 95% nitrogen into the insulation via vertically positioned, perforated pipes or porous flexible pipes, ensuring even distribution across the chamber, particularly above insulated elements, to maintain a dry atmosphere and prevent condensation and ignition risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If nitrogen is sent through an opening in the roof of the chamber, then the nitrogen passes freely through the insulation, but the distribution of nitrogen is not good
Solution Approach 1:
The distribution system is segmented into multiple injection points positioned at different locations (roof, walls, bottom) of the chamber. This segmentation allows nitrogen to be injected at multiple strategic positions, creating a more uniform distribution pattern throughout the insulation rather than relying on a single opening.
Solution Approach 2:
Different regions of the chamber are provided with different injection characteristics. The roof opening provides top-down flow, wall injections provide lateral distribution, and bottom injections provide upward flow. Each location is optimized for its specific position to achieve overall uniform distribution.
2Ease of operation
If gaseous nitrogen is sent from the distillation into the insulation by means of a distributer positioned in the middle of the mass of insulation, then nitrogen is injected centrally, but optimal distribution of the inert gas is not achieved
Solution Approach 1:
The single central distributer is replaced by multiple injection points distributed throughout the chamber structure (roof, walls, bottom). This segmentation eliminates the concentration of flow at one location and enables nitrogen to reach all regions of the insulation more uniformly.
Solution Approach 2:
The injection system transitions from a single-point (0D) or localized (2D) distribution to a three-dimensional distribution network. Injection points are positioned at roof, walls, and bottom, creating volumetric coverage that ensures uniform gas distribution throughout the entire insulation mass.
3Reliability
If nitrogen is used to maintain a dry atmosphere with slight overpressure, then moisture ingress is prevented, but the thermal performance of the insulation is impaired if moisture enters
Solution Approach 1:
Nitrogen injection is implemented as a preliminary and continuous protective action before and during any potential moisture ingress scenarios. By maintaining continuous nitrogen flow and positive pressure, the system proactively prevents moisture entry rather than reacting after contamination occurs.
Solution Approach 2:
An inert nitrogen atmosphere is established and maintained within the insulation chamber. This inert environment prevents both moisture ingress and oxygen-related safety hazards, creating a protective atmosphere that preserves insulation thermal performance and ensures operational safety.
4Object-affected harmful factors
If air enters the insulation, then oxygen-enriched air may condense below the dew point, but the risk of ignition and explosion increases
Solution Approach 1:
Nitrogen injection creates and maintains an inert atmosphere within the insulation, replacing oxygen-containing air with nitrogen. This eliminates the risk of oxygen-enriched air condensation and removes the ignition hazard entirely, as nitrogen is non-flammable and displaces oxygen needed for combustion.
Solution Approach 2:
The system applies preliminary anti-action by continuously injecting nitrogen to prevent the formation of flammable or oxygen-enriched conditions before they can occur. The inerting action counteracts any potential air ingress that could lead to condensation or ignition hazards.
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 enhances nitrogen distribution within the insulated chamber, improving thermal performance, reducing the risk of moisture ingress and ignition, while simplifying installation and reducing costs by using less expensive and lighter porous pipes, ensuring comprehensive flushing and efficient operation.
Implementation Method 1
at least some of the means for injecting the gas into the insulation open into the insulation arranged at a position vertically above at least one element that is to be insulated, so that the gas can seep out
Data Source
AI summary
The invention relates to an insulated chamber comprising at least one element that may operate at sub-ambient temperature, the space around the element(s) being filled with solid insulation and means for injecting a gas containing at least 95 mol-% nitrogen into the insulation, at least some of the gas-injection means opening at a position vertically above at least one element to insulate.