Method for producing one or more air products and air separation system
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional air separation plants face challenges in achieving flexible and rapid load changes, leading to imbalances in cryogenic liquid distribution and deteriorating product purity during transitions in production volume.
Innovation Solution
Implementing a delayed or leading setpoint adjustment of fluid streams in the rectification column system, particularly the nitrogen-rich liquid reflux, to synchronize with changes in total air quantity processed, allowing for smoother load changes without compromising product purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rapid load changes are implemented in air separation plants, then flexibility and productivity are improved, but product purity deteriorates due to imbalances in cryogenic liquid distribution
Solution Approach 1:
The control system performs preliminary actions by adjusting the nitrogen-rich liquid reflux quantity in advance before the actual load change occurs. When a load increase is detected, the system increases the reflux quantity beforehand to prevent purity deterioration. This proactive adjustment ensures that the rectification columns maintain proper liquid distribution even during rapid load changes, thereby preserving product purity while enabling flexible productivity changes.
2Stability of the object's composition
If conventional control methods are used during load changes, then system stability is maintained, but flexibility and rapid load changes are limited
Solution Approach 1:
The control system dynamically adapts the nitrogen-rich liquid reflux quantity based on real-time load conditions. Rather than using fixed conventional control parameters, the system continuously adjusts the reflux flow rate in response to load changes. This dynamic control approach allows the plant to rapidly transition between load conditions while maintaining system stability through active compensation of cryogenic liquid distribution imbalances.
3Manufacturing precision
If backup storage facilities with higher capacities are provided to support load changes, then product purity is maintained, but construction costs increase
Solution Approach 1:
The control system enables the air separation plant to self-regulate during load changes by automatically adjusting the nitrogen-rich liquid reflux quantity. This self-service capability eliminates the need for large backup storage facilities, as the control system itself provides the necessary compensation for load transitions. The plant uses its own internal resources (reflux control) rather than requiring external backup infrastructure, thereby reducing construction costs while maintaining product purity.
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
Enables flexible and rapid load changes with minimal impact on product purity, reducing the need for backup storage and potentially lowering construction and operating costs.
Implementation Method 1
The production of air products in liquid or gaseous state by cryogenic separation of air in air separation plants is known and described
Implementation Method 2
The rectification columns of the aforementioned rectification column systems are operated at different pressure levels
Implementation Method 3
heat exchanger for cooling and heating of gas streams in counter-current heat exchange
Implementation Method 4
a main condenser for condensing a gaseous, nitrogen-rich overhead product of the high-pressure column
Implementation Method 5
an evaporator for evaporating a liquid oxygen product
Implementation Method 6
compressed air in an adjustable total air quantity
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a method for obtaining one or more air products, wherein an air separation system (100) having a rectification column system (10) is used, in which pressurised air is processed in an adjustable total air volume, wherein the total air volume is set to a first value during a first operating period (T1) and set to a second value that is different from the first value during a second operating period (T2), and wherein the setting of the total air volume is changed from the first value to the second value in a third operating period (T3) from a first time (X1) to a second time (X2). The second operating period (T2) is after the first operating period (T1), the third operating period (T3) is between the first operating period (T1) and the second operating period (T2). According to the invention, in the third operating period (T3), a setting of a volume of a fluid, which is formed via rectification using the pressurised air and transported in or out of the rectification column system (10), is changed from a third time (X3) up to a fourth time (X4), wherein the third time (X3) is before or after the first time (X1) and before the second time (X2), and the fourth time (X4) is after the first time (X1) and the third time (X3) and before or after the second time (X2). A time period between the first time (X1) and the second time (X2) is set to be substantially the same as a time period between the third time (X3) and the fourth time (X4). The invention also relates to a corresponding air separation system (100).