Method for the low-temperature decomposition of air and air separation plant
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Solution Overview
Problem
Conventional air separation plants with mixing columns have a limited injection equivalent, leading to increased energy consumption and operational costs due to inefficient air flow participation in the rectification process, resulting in a lower oxygen yield and higher energy demands.
Innovation Solution
The method involves feeding an oxygen-enriched liquid from the high-pressure column into a mass transfer column, where it is evaporated and the resulting gas is fed into the low-pressure column at a higher position, optimizing the liquid/vapor ratios and rectification conditions, allowing for a higher injection equivalent and reduced energy requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional mixing columns are used with limited injection equivalent, then the air separation plant can operate with simpler construction, but the energy consumption increases and oxygen yield decreases
Solution Approach 1:
The patent changes the fundamental parameter of how air is introduced into the distillation system by using a vaporizer to convert liquid air into vapor that is fed into the mixing column, rather than introducing compressed liquid air directly. This parameter change enables higher injection equivalent while maintaining construction simplicity and resolving the energy consumption issue.
Solution Approach 2:
The patent employs phase transition by using a vaporizer to convert liquid air into vapor phase before introducing it into the mixing column. This phase change allows the air to participate more effectively in the rectification process, increasing oxygen yield and reducing energy consumption while maintaining simpler construction.
2Productivity
If the injection equivalent is increased to improve oxygen yield, then more air can participate in rectification, but the existing mixing column design becomes inefficient and energy consumption increases
Solution Approach 1:
The patent changes the state parameter of the injected air from liquid to vapor phase using a vaporizer, which enables efficient mass transfer in the mixing column at higher injection equivalents. This parameter change allows increased oxygen yield without the energy penalties associated with conventional liquid injection methods.
Solution Approach 2:
The vaporizer acts as an intermediary device that converts liquid air into vapor, serving as a mediator between the liquid air supply and the mixing column. This intermediary enables efficient integration of high volumes of air into the rectification process, improving oxygen yield while maintaining energy efficiency.
3Device complexity
If compressed air is fed directly into the mixing column as liquid, then the system requires less equipment, but the air flow does not participate optimally in the rectification process
Solution Approach 1:
The patent uses phase transition in the vaporizer to convert liquid air into vapor phase, which dramatically improves rectification efficiency. The vapor phase air participates optimally in mass transfer within the mixing column, resolving the contradiction between equipment simplicity and rectification efficiency.
Solution Approach 2:
The patent replaces the mechanical direct-injection system with a thermal field-based system using a vaporizer. This substitution uses thermal energy to achieve phase change, enabling superior mass transfer and rectification efficiency without requiring complex mechanical injection systems.
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 significantly enhances the efficiency of air separation, reduces the power needed for rectification, and minimizes the volume of the main heat exchanger, enabling energy savings and lower construction costs by optimizing the air flow participation in the rectification process.
Implementation Method 1
wherein the oxygen-enriched liquid is evaporated and the gas formed is fed into the low-pressure column
Implementation Method 2
liquid evaporation by heat exchange with a condensing gas
Data Source
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AI summary
A process for the low-temperature separation of air using an air separation unit (100-900) is proposed, wherein a liquid first fluid and a gaseous second fluid are subjected to mass transfer in a mass transfer column (13), wherein a gaseous third fluid is withdrawn from the mass transfer column (13) and at least partially discharged from the air separation unit (100-900), wherein a liquid fourth fluid is withdrawn from the mass transfer column (13) and at least partially fed into a low-pressure column (12), and wherein the first fluid is formed using at least a portion of an oxygen-rich liquid withdrawn from the low-pressure column (12). The second fluid is formed using an oxygen-enriched liquid withdrawn from a high-pressure column (11).The oxygen-enriched liquid taken from the high-pressure column (11) and the bottom liquid from the mass transfer column (13) are mixed and partially evaporated by means of a condenser evaporator (7), in which a liquid stream comprising at least a part of the oxygen-enriched liquid taken from the high-pressure column (11) and at least a part of the bottom liquid from the mass transfer column (13) is forced through an evaporation chamber by means of its own pressure and is partially evaporated there.A fifth liquid fluid is withdrawn from the mass transfer column (13) between an inlet for the first fluid and an inlet for the oxygen-enriched liquid and at least partially fed into the low-pressure column (12), wherein the fifth fluid, or the portion thereof fed into the low-pressure column (12), is fed into the low-pressure column (12) below the fourth fluid, or the portion thereof fed into the low-pressure column (12). An air separation unit (100-900) is also part of the invention.