System and method for production of argon by cryogenic rectification of air
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Solution Overview
Problem
Conventional argon recovery processes in cryogenic air separation units are costly and inefficient, with tall column/coldbox heights and complex argon condensing assemblies that increase capital expenses and safety concerns due to potential vaporization of kettle liquids.
Innovation Solution
A method and system where an argon condensing assembly is disposed within the lower pressure column of an air separation unit, utilizing an oxygen-enriched mixed liquid stream to condense argon-rich vapor, with a stripping reflux condenser or once-through condenser cores to enhance argon recovery, reducing capital costs and improving safety by maintaining adequate liquid flow to prevent boiling to dryness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional argon condensing assembly is used with multiple thermo-syphon type condensers in a large separation vessel, then argon recovery is achieved, but the column/coldbox height increases to over 200 feet and capital expenses increase
Solution Approach 1:
The argon condensing assembly is merged with the lower pressure distillation column by disposing the condenser internally within the column structure. The condenser is positioned in the lower portion of the column where it can utilize the existing column infrastructure, eliminating the need for a separate large separation vessel and reducing overall column height while maintaining argon recovery functionality
Solution Approach 2:
The argon condenser is nested within the lower pressure distillation column structure. The condenser tubes are positioned inside the column, utilizing the column's existing walls and support structure, thereby reducing the external dimensions and capital expenses associated with a separate condensing vessel
2Reliability
If a conventional argon condensing assembly with large separation vessel and external plumbing is used, then argon condensation is achieved, but device complexity and capital expenses increase
Solution Approach 1:
The argon condensing function is merged with the distillation column structure, eliminating external plumbing requirements. The condenser is integrated into the column with internal fluid distribution systems, reducing device complexity and capital expenses while maintaining effective argon condensation
Solution Approach 2:
The complex external plumbing and large separation vessel are extracted from the system. The invention uses a simplified internal condenser design within the column that eliminates the need for external vessels and complex piping, reducing device complexity while maintaining condensation functionality
3Reliability
If kettle liquid is drawn into the bottom of condensers and flows upwards boiling to absorb heat from argon vapor, then argon condensation is achieved, but safety risk increases due to potential complete vaporization of kettle liquid
Solution Approach 1:
The flow direction is inverted from the conventional upward flow to a downward flow of liquid through the condenser tubes. Liquid is introduced at the top of the condenser and flows downward, counter-current to the rising argon vapor. This inversion ensures that liquid is always present in the tubes to absorb heat and prevents complete vaporization, eliminating the safety risk while maintaining condensation efficiency
Solution Approach 2:
The downward flow arrangement provides preliminary protection against complete vaporization by ensuring liquid continuously replenishes the heat absorption surfaces from the top. This prevents the harmful condition of dry boiling before it can occur, enhancing safety while maintaining effective argon condensation
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 reduces capital expenses, simplifies the coldbox design, and enhances argon recovery efficiency while ensuring safe operation by maintaining sufficient liquid flow to prevent boiling to dryness, thereby improving the cost-effectiveness and safety of argon production.
Implementation Method 1
condensing the argon rich vapor stream against the oxygen-enriched mixed liquid stream in the argon condensing assembly
Implementation Method 2
condense the argon rich vapor stream
Implementation Method 3
vaporizing a portion of the oxygen-enriched mixed liquid stream
Implementation Method 4
boiling as it absorbs heat from the argon vapor
Implementation Method 5
cryogenic rectification of air using a multiple column distillation system
Data Source
AI summary
A system and method for producing argon that uses a higher pressure column, a lower pressure column, and an argon column collectively configured to produce nitrogen, oxygen and argon products through the cryogenic separation of air. The present system and method also employs a once through argon condensing assembly that is disposed entirely within the lower pressure column that is configured to condense an argon rich vapor stream from the argon column against the oxygen-enriched liquid from the higher pressure column to produce an argon liquid or vapor product. The control system is configured for optimizing the production of argon product by ensuring an even flow split of the oxygen-enriched liquid is distributed to the argon condenser cores and by adjusting the flow rate of the argon removed from the argon condensing assembly to maintain the liquid/vapor balance in the argon condensing assembly within appropriate limits.