Cryogenic Air Separation with Turbine-Driven Cold Compression
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Solution Overview
Problem
Existing air separation methods struggle to efficiently manage a wide variation in the proportion of liquid product output, particularly in achieving maximum liquid production while maintaining energy efficiency across different operating modes.
Innovation Solution
The method employs a turbine-driven cold compressor, which operates at a lower load during high liquid production modes and is optimized for efficient energy consumption by adjusting air flow and pressures across multiple compressor stages, allowing for flexible liquid product variation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional air separation method is used to achieve maximum liquid production, then liquid product output is improved, but energy consumption increases significantly
Solution Approach 1:
The patent applies dynamics by making the compressor loading flexible and adjustable based on operating mode. The cold compressor can operate at different loading levels (lower in first mode for liquid production, higher in second mode for gas production), allowing the system to adapt its energy consumption to the required product output, thereby resolving the contradiction between maximum liquid production and energy efficiency
Solution Approach 2:
The patent changes operational parameters (compressor loading, air flow distribution, pressure settings) to optimize performance for different operating modes. By adjusting these parameters, the system achieves satisfactory energy efficiency in both high liquid production mode and low liquid production mode, resolving the contradiction between productivity and energy consumption
2Productivity
If the cold compressor operates at high load to increase liquid production, then productivity is improved, but energy efficiency deteriorates
Solution Approach 1:
The system dynamically adjusts the cold compressor loading based on the operating mode. In the first operating mode optimized for liquid production, the cold compressor operates at lower load with optimized air flow distribution, achieving acceptable energy efficiency. This dynamic adaptation resolves the contradiction between high liquid production and energy efficiency
3Productivity
If the system is optimized for high liquid production mode, then liquid product output is improved, but adaptability to different operating modes deteriorates
Solution Approach 1:
The patent designs the air separation system with multi-functionality to handle different operating modes effectively. The cold compressor and air flow distribution system can be configured for either maximum liquid production (first mode) or optimized energy efficiency (second mode), making the system universally applicable to varying operational requirements while maintaining satisfactory performance in both modes
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 a significant variation in liquid product output with satisfactory energy efficiency in both high and low liquid production modes, reducing overall energy consumption and maintaining operational efficiency.
Implementation Method 1
a turbine-driven cold compressor (14c, 202c) is used, which is run at a lower load in the first operating mode than in the second
Implementation Method 2
a pressurized liquid first product stream is vaporized in the main heat exchanger and finally recovered as a gaseous pressurized product
Implementation Method 3
Against the (pseudo-)evaporating product stream, a high-pressure heat carrier is liquefied (or pseudo-liquefied if it is under supercritical pressure)
Data Source
Figure 1
AI summary
The method and device are used for the low-temperature separation of air in an air separation plant which has a main air compressor, a main heat exchanger (8) and a distillation column system with a high-pressure column (10) and a low-pressure column. All of the feed air (1) is compressed in the main air compressor (3) to a first air pressure that is at least 3 bar higher than the operating pressure of the high-pressure column. A first part of the compressed total air flow is cooled and liquefied or pseudo-liquefied as the first air flow (100) under the first air pressure in the main heat exchanger (8), then expanded (101) and introduced into the distillation column system (102, 9). A second part of the compressed total air flow is post-compressed as a second air flow (200) in a turbine-driven post-compressor (202c) to a second air pressure. A first partial flow of the second air flow is introduced as a third air flow (210) under the second air pressure and at a first temperature (T1) into a first turbine (202t), expanded there to produce work and then introduced into the distillation column system (211, 213, 22), wherein the first turbine (202t) drives the first turbine-driven booster (202c). At least temporarily, at least one liquid product (30; 39; LAR) is recovered in the distillation column system and withdrawn from the air separation unit. A first product stream (37; 43) is withdrawn in liquid form from the distillation column system, brought to a first increased product pressure in the liquid state (41; 44), evaporated or pseudo-evaporated and heated in the main heat exchanger (8) and then as the first compressed gas product won. At least temporarily, a second partial flow of the second air flow is further compressed as a fourth air flow (230) in the main heat exchanger (8) in a cold compressor (14c) to a third air pressure, cooled in the main heat exchanger (8) and liquefied or pseudo-liquefied, then expanded ( 233) and introduced into the distillation column system (234, 9). The fourth air stream (230) flowing through the cold compressor (14c) has at least one of the following properties: - its volume is greater in the second operating mode than in the second operating mode - its pressure at the outlet of the cold compressor is higher in the second operating mode than in the first Operation mode.