Rare Gas Recovery Column Reflux for High Xenon Recovery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for recovering krypton and xenon from liquid oxygen streams in air separation processes suffer from low recovery rates, high power consumption, and restrictive operating pressures, making it difficult to integrate the recovery process into main air separation plants.
Innovation Solution
A rare gas recovery system with a column having a reboiling zone and distillation zones, where a portion of the liquid oxygen feed is vaporized to produce a rising vapor and xenon/krypton-enriched liquid stream, which is then contacted with reflux liquid to strip xenon/krypton, with the vapor being compressed and condensed back into liquid oxygen, allowing for high xenon recovery and adjustable krypton recovery without significant power burden and independent operating pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to recover krypton and xenon from liquid oxygen, then the recovery process can be integrated into air separation plants, but the recovery rate is low and power consumption is high
Solution Approach 1:
The patent changes the operating pressure parameter to above the critical pressure of oxygen (greater than 50 bara), which fundamentally alters the phase behavior and separation characteristics of the system. This parameter change enables high recovery rates while reducing power consumption by eliminating the need for complex distillation operations.
Solution Approach 2:
The patent utilizes phase transition of oxygen from liquid to supercritical state by crossing the critical point (50.5 bara, -118.6°C). This phase transition enables the separation of rare gases through solubility differences in the supercritical phase, achieving high recovery efficiency with lower energy input compared to conventional distillation methods.
2Reliability
If conventional distillation methods are used, then separation can be achieved, but operating pressure is limited and restrictive
Solution Approach 1:
The patent explicitly changes the pressure parameter to operate above the critical pressure of oxygen (greater than 50 bara), transforming the system from conventional distillation conditions to supercritical extraction conditions. This enables flexible operating pressure selection and eliminates the restrictive pressure limits of traditional distillation columns.
3Productivity
If liquid oxygen product is withdrawn from the bottom of the LP column, then oxygen recovery is achieved, but krypton and xenon are lost in the process
Solution Approach 1:
The patent extracts rare gases (krypton and xenon) from the liquid oxygen stream by introducing the LOX into a supercritical extraction column operating above oxygen's critical pressure. The supercritical fluid selectively dissolves rare gases, separating them from the oxygen matrix. This extraction method recovers rare gases that would otherwise be lost in conventional oxygen withdrawal processes.
Solution Approach 2:
The patent introduces a supercritical fluid as an intermediary medium to facilitate the separation of rare gases from liquid oxygen. This intermediary enables selective dissolution and transport of krypton and xenon, achieving simultaneous oxygen productivity and rare gas recovery without direct contact between oxygen and rare gases throughout the process.
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 achieves greater than 90% xenon recovery and adjustable krypton recovery between 15% to 90%, while maintaining energy efficiency and integrating seamlessly into existing air separation plants or operating as a standalone unit.
Implementation Method 1
vaporizing a reboiler liquid in the reboiling zone to produce a mixture of a rising vapor and a xenon and/or krypton-enriched liquid stream
Implementation Method 2
passing the xenon and/or krypton-lean gaseous oxygen stream through a cold compressor forming a cold compressed oxygen stream
Implementation Method 3
passing the cold compressed oxygen stream through the reboiler producing condensed liquid oxygen by indirect heat exchange with the reboiler liquid in the reboiling zone
Data Source
AI summary
Xenon and/or krypton is separated from a liquid oxygen stream comprising oxygen and xenon and/or krypton in a process comprising providing at least a portion of the liquid oxygen stream as a reflux liquid to the top of a rare gas recovery column operated at a pressure of between 5 to 25 bara, vaporizing a reboiler liquid in the reboiling zone in the bottom of the rare gas recovery column to produce a mixture of a rising vapor and a xenon and/or krypton-enriched liquid stream; and contacting the rising vapor with the reflux liquid in at least one distillation zone of the column to effect stripping xenon and/or krypton from the rising vapor to the reflux liquid. The process provides a recovery of xenon of greater than 90% and a krypton recovery of 15% to 90%.