Air Separation Cold Compressor Switching for Variable Liquid Output
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Solution Overview
Problem
Existing air separation methods struggle to efficiently manage varying liquid product proportions, particularly in maximizing liquid production while maintaining energy efficiency and flexibility between different operating modes.
Innovation Solution
The method employs a cold compressor that can be switched on or off and operated at different loads depending on the operating mode, along with a turbine-cold compressor combination, to optimize liquid production and energy consumption across varying liquid product proportions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a cold compressor is added to maximize liquid production, then liquid product amount increases, but device complexity and energy consumption increase
Solution Approach 1:
The cold compressor is designed to serve multiple functions: it can operate independently to maximize liquid production, or it can be coupled with the turbine to provide both compression and power generation. The system can switch between different operating modes (first operating mode with cold compressor only, second operating mode with turbine-cold compressor combination, third operating mode with turbine only) to adapt to different production requirements, making the compressor system universal and multi-functional.
Solution Approach 2:
The system incorporates dynamic switching capabilities between different operating modes. The cold compressor can be dynamically coupled or decoupled from the turbine based on production requirements. The control system dynamically adjusts the operation of the cold compressor and turbine combination to optimize performance for either maximum liquid production or energy efficiency, making the system adaptable and dynamic rather than static.
2Use of energy by moving object
If turbine-cold compressor combination is used for energy efficiency, then energy consumption decreases, but liquid production capability is reduced
Solution Approach 1:
The turbine and cold compressor are merged into a combined system where the turbine drives the cold compressor. This merging allows the system to recover energy from the expansion process and use it for compression, significantly improving energy efficiency. The combined system operates as an integrated unit where waste energy from one component becomes useful energy for another component.
Solution Approach 2:
The system can dynamically switch between the turbine-cold compressor combination mode (for energy efficiency) and the cold compressor independent mode (for maximum liquid production). This dynamic capability allows the system to optimize for energy consumption when liquid production requirements are moderate, while still maintaining the ability to maximize liquid production when needed.
3Productivity
If cold compressor operates independently for maximum liquid production, then liquid production increases, but energy efficiency decreases
Solution Approach 1:
The system incorporates dynamic switching capabilities that allow the cold compressor to operate independently when maximum liquid production is required, or to be coupled with the turbine when energy efficiency is the priority. This dynamic reconfiguration enables the system to adapt its energy consumption characteristics based on production requirements.
4Adaptability or versatility
If system is designed for flexible operation between modes, then adaptability increases, but device complexity increases
Solution Approach 1:
The cold compressor and turbine combination is designed with universal functionality to operate in multiple modes: independent cold compressor operation, turbine-cold compressor combination operation, and turbine-only operation. This multi-functionality is achieved through universal coupling mechanisms and control systems that can seamlessly switch between different operational configurations, making the system adaptable to various production scenarios.
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 allows for a strong variation in liquid product amounts with satisfactory efficiency in both high and low liquid production modes, achieving low energy consumption and flexible operation.
Implementation Method 1
a first set 3a of a main air compressor and a second set 3b of air compressor stages, in particular a cold compressor, whose discharge is connected to the suction of the first turbine-driven booster
Implementation Method 2
a turbine-driven booster (202c, 50c), in particular a first and a second turbine-driven booster, whose drive is formed by a turbine (202t, 50t)
Implementation Method 3
a main heat exchanger (8), in particular a main heat exchanger with a cold end and a warm end
Implementation Method 4
a distillation column system comprising a high-pressure column (10), a main condenser-evaporator (11) and a low-pressure column (12)
Data Source
Figure 1
Figure 1A
Figure 1B
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 (3a) to a first air pressure which 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 an air booster (3b) to a second air pressure and at least partially further compressed to a third air pressure in a first turbine-driven booster (202c). A first partial flow of the second air flow is introduced as a third air flow (210) under a first turbine inlet pressure into a first turbine (202t), expanded there to perform work and then introduced into the distillation column system (211, 213, 22), the first turbine inlet pressure being greater than the first barometric pressure but not greater than the third barometric pressure, and the first turbine (202t) drives the first turbine driven booster (202c). A second partial flow of the second air flow is cooled as a fourth air flow (220) under a pressure that is greater than the first air pressure, but not greater than the third air pressure, in the main heat exchanger (8) and liquefied or pseudo-liquefied, then expanded ( 221) and introduced into the distillation column system (222). 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 third partial flow of the second air flow is further compressed as a sixth air flow (230) in the main heat exchanger (8) in a cold compressor (14c) to a fourth 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). In a first operating mode with high liquid production, the amount of air that is passed through the cold compressor (14c) as sixth air flow (230) is less than in a second operating mode with lower liquid production.