Cryogenic air separation apparatus
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Solution Overview
Problem
Existing cryogenic air separation methods face inefficiencies in recovering nitrogen, argon, and high-purity oxygen due to proportional reductions in intermediate-pressure nitrogen gas and feed air supply, leading to reduced argon recovery and economic inefficiencies.
Innovation Solution
A cryogenic air separation apparatus with a heat exchanger, multiple rectification columns, and a high-purity oxygen rectification column using compressed recycled nitrogen gas as a reboiling source, enhancing reflux liquid and argon recovery by utilizing the oxygen-rich liquid and nitrogen gas efficiently across the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If intermediate-pressure nitrogen gas is used as a reboiling source for high-purity oxygen, then high-purity oxygen can be produced, but the quantity of intermediate-pressure nitrogen gas supplied to the low-pressure column bottom portion is reduced, leading to reduced argon recovery
Solution Approach 1:
The patent introduces a heat exchanger as an intermediary device that enables thermal energy transfer between the oxygen-rich liquid and the nitrogen gas. This allows the oxygen-rich liquid to serve as a reboiling source for high-purity oxygen while simultaneously preheating the nitrogen gas that will be supplied to the low-pressure column, thus maintaining argon recovery capability without compromising high-purity oxygen production
Solution Approach 2:
The patent changes the thermal parameters of the nitrogen gas by passing it through the heat exchanger where it is preheated by the oxygen-rich liquid. This parameter change (temperature increase) allows the nitrogen gas to fulfill dual functions: maintaining argon recovery in the low-pressure column and serving as an effective reboiling source for high-purity oxygen production
2Manufacturing precision
If feed air is used as a reboiling source for high-purity oxygen, then high-purity oxygen can be recovered, but the feed air supply to the intermediate-pressure column is reduced, leading to reduced nitrogen recovery
Solution Approach 1:
The heat exchanger acts as an intermediary that transfers thermal energy from the oxygen-rich liquid to the feed air. This enables the feed air to be preheated before entering the intermediate-pressure column, maintaining nitrogen recovery capability while allowing the oxygen-rich liquid to serve as the reboiling source for high-purity oxygen production
3Manufacturing precision
If oxygen-rich liquid from intermediate-pressure column bottom portion is used as a reboiling source, then high-purity oxygen can be recovered, but only limited sensible heat corresponding to temperature difference can be utilized
Solution Approach 1:
The patent replaces the direct thermal contact method (which is limited by temperature difference) with a heat exchanger-based thermal energy transfer system. This substitution allows for more efficient energy utilization by enabling controlled heat transfer between the oxygen-rich liquid and the nitrogen gas or feed air, maximizing the use of sensible heat from the oxygen-rich liquid
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 configuration allows for high-yield recovery of nitrogen, argon, and high-purity oxygen, improving economic efficiency by maintaining argon recovery while reducing energy consumption through optimized compression ratios and reflux liquid usage.
Implementation Method 1
a heat exchanger (1) for subjecting feed air to heat exchange
Implementation Method 2
a first condenser (nitrogen condenser) (3) which is disposed above the first column top portion (23) and condenses the first vaporized gas in the first column top portion (23)
Implementation Method 3
an oxygen column bottom portion (81) having a high-purity oxygen vaporizer (9) disposed in a lower region thereof
Data Source
AI summary
A cryogenic air separation apparatus comprises: a heat exchanger, a first rectification column, a first condenser, a second rectification column, a third rectification column, a second condenser, a high-purity oxygen rectification column, a third condenser, a nitrogen compressor, and a compressed recycled gas line L52 for introducing product nitrogen gas compressed by the first nitrogen compressor into a warm end (heat source) of an ultra-high-purity oxygen vaporizer as a compressed recycled gas.