Method and apparatus for cryogenic air separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cryogenic air separation methods cannot regulate liquid output to meet different yield requirements, as they lack the flexibility to adjust production according to actual needs.
Innovation Solution
The method involves compressing air to a higher pressure, partially cooling and expanding it through turboexpanders and boosters, and regulating the flow rates to vary the refrigeration input to the rectification column system, allowing for adjustment of liquid output yields by modifying the enthalpy drop and compression work.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional cryogenic air separation method is used, then the system structure is simple, but the liquid output yield cannot be regulated to meet different requirements
Solution Approach 1:
The feed air stream is divided into multiple parts with different processing paths: one part is expanded in a turboexpander to provide refrigeration, another part is compressed in a booster compressor to high pressure, and a third part is expanded in a second turboexpander. This segmentation allows independent control of refrigeration input and liquid output yield without requiring complete system redesign.
Solution Approach 2:
The system employs dynamic flow rate regulation of the air streams passing through the turboexpanders and booster compressor. By adjusting the flow rates of different air parts, the refrigeration input to the rectification column can be dynamically controlled, enabling flexible regulation of liquid output yield according to actual requirements.
2Productivity
If the refrigeration input is increased to increase liquid output yield, then the productivity improves, but the energy consumption increases
Solution Approach 1:
The turboexpanders utilize the expansion of compressed air to generate refrigeration effect and drive the booster compressor, creating a self-sustaining system where the expansion work directly provides the refrigeration needed for liquid production. This reduces the need for external energy input while maintaining high productivity.
Solution Approach 2:
The system changes the pressure and temperature parameters of different air streams to optimize the refrigeration effect. By controlling the pressure ratios and flow rates through the turboexpanders and booster, the system achieves efficient refrigeration with minimized energy consumption across different productivity levels.
3Measurement precision
If multiple compression stages are added to regulate flow rates, then the flow rate control precision improves, but the device complexity increases
Solution Approach 1:
The turboexpanders and booster compressor serve multiple functions simultaneously: they compress/expand air for pressure regulation, generate refrigeration effect for cooling, and control flow rates for yield regulation. This multi-functionality achieves precise flow rate control without adding dedicated compression stages, thereby avoiding increased device complexity.
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 enables the apparatus to produce liquid output at varying yields by regulating the flow rates through turboexpanders and boosters, increasing or decreasing the refrigeration input, thus adapting to different requirements without the need for additional recompressors, reducing energy consumption and system complexity.
Implementation Method 1
a first part of the air of the third pressure is partially cooled in the main heat exchanger and expanded in a first turboexpander
Implementation Method 2
a main heat exchanger and a rectification column system which has a low-pressure column operating at a first pressure and a high-pressure column operating at a second pressure
Implementation Method 3
further compressing a second part of the air at the third pressure in a first booster to form air at a fourth pressure
Implementation Method 4
feeding all parts of the total feed air to the rectification column system at the first and/or the second pressure, at least some of the air being sent to the high pressure column, and obtaining a liquid stream from the rectification column system
Data Source
Figure 1
AI summary
In a method for cryogenic air separation, part (b2) of the air (b) is compressed in warm booster (7), cooled in heat exchanger (2) and then divided in two, one part (c1) being compressed in a cold booster(9) driven by the Claude turbine (11) in which the other part (c2) of air (c) is expanded, another part of the feed air is not booster but is expanded in another Claude turbine (6) which drives the warm booster (7).