Device and method for separating air by cryogenic distillation
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Solution Overview
Problem
Existing air separation technologies face challenges in producing large quantities of gaseous oxygen at pressures below 9 bars abs, with oxygen concentrations below 98% mol, while maintaining stable production and pressure, particularly for oxycombustion devices.
Innovation Solution
The apparatus and method involve vaporizing the deconcentration purge of a vaporizer in an exchanger to recover negative calories, using a separate exchanger connected to the purge oxygen line, which also handles air and refrigerant flows, and pressurizing the purge oxygen to at least 10 bar abs to maintain a stable gaseous product under pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If liquid oxygen is vaporized in an external vaporizer to produce gaseous oxygen at low pressure, then gaseous oxygen can be produced, but the production pressure is limited and requires additional pressurization equipment
Solution Approach 1:
The patent combines the vaporization function and pressurization function into a single integrated device. The exchanger serves both to vaporize liquid oxygen and to pressurize the resulting gaseous oxygen to at least 10 bar abs, eliminating the need for separate external vaporizer and pressurization equipment while maintaining efficient oxygen production
Solution Approach 2:
The exchanger is designed to perform multiple functions simultaneously: it acts as a heat exchanger for vaporization, a pressurization device for achieving high pressure output, and a mixing chamber for combining purge oxygen with pressurized oxygen. This multi-functionality reduces system complexity while improving production efficiency
2Loss of energy
If purge oxygen is vented without recovery, then system operation is simplified, but energy is wasted and production stability is reduced
Solution Approach 1:
The patent converts the previously wasted purge oxygen, which carries away valuable cold temperatures, into a useful resource. The purge oxygen is routed through the exchanger where it pre-cools incoming liquid oxygen and contributes to the vaporization process, transforming an energy loss into an energy recovery mechanism that improves overall system efficiency
Solution Approach 2:
Instead of discarding the purge oxygen stream, the system recovers its cooling capacity by directing it through the exchanger. The cold purge oxygen pre-cools the feed liquid oxygen and participates in the vaporization process, recovering the cold temperatures that would otherwise be lost and reducing the energy required for heating
3Stability of the object's composition
If purge oxygen is not pressurized, then equipment requirements are reduced, but production pressure stability cannot be maintained
Solution Approach 1:
The patent merges the pressurization function with the vaporization exchanger. The exchanger is designed to deliver gaseous oxygen at a pressure of at least 10 bar abs directly from the vaporization process, combining thermal and mechanical functions in one device and eliminating the need for separate pressurization equipment while maintaining stable pressure output
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 ensures a stable production of gaseous oxygen with varying flow rates and pressures, allowing for efficient oxygen supply to oxycombustion devices and providing a backup during apparatus failures, ensuring continuous operation.
Implementation Method 1
The exchanger comprises passages connected to a feed air supply pipe and passages connected to a refrigerant supply pipe
Implementation Method 2
vaporize the deconcentration purge of a vaporizer in an exchanger to recover negative calories
Implementation Method 3
pressurizing the purge oxygen to at least 10 bar abs to maintain a stable gaseous product under pressure
Implementation Method 4
All the air 1 is compressed in the main compressor 2 to produce air at the pressure P1 substantially equal to the pressure of the medium pressure column 27
Implementation Method 5
expanded in a turbine 19 coupled to the booster 17 before being sent to the low pressure column 29
Data Source
Figure 1
Figure 2
AI summary
Device for separating air comprises a pipe for withdrawing liquid oxygen from the low-pressure column and for sending it to a first pump (39), a pipe for sending liquid oxygen that has been pressurized to a pressure of below 9 bar abs from the first pump to a vaporizer (41), a pipe for sending gaseous oxygen from the vaporizer to a main exchanger (21) where it is heated up, a pipe for sending liquid oxygen for purging from the vaporizer to a second pump (63) to pressurize it and a pipe for sending the pressurized oxygen from the second pump to an exchanger where it vaporizes to form gaseous oxygen.