Air Fractionation Control for Stable and Fast Load Changes
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Solution Overview
Problem
Low-temperature air fractionation systems face challenges in achieving stable operation and rapid load changes while maintaining high product yield and production flexibility, as existing control technologies like ALC and MPC controllers have limitations in handling variable loads and intercoupled multi-variable systems.
Innovation Solution
A process that combines ALC control and MPC controller to dynamically adjust setpoint values for process parameters, where ALC outputs target values to MPC, which calculates and adjusts setpoint values for basic controllers, enabling simultaneous stable operation and rapid load changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If ALC control is used to achieve rapid load changes, then load changing rate is improved, but system stability deteriorates
Solution Approach 1:
The control system dynamically switches between ALC mode (for rapid load changes) and MPC mode (for stable steady-state operation). The system adapts its control strategy based on operational requirements, enabling both fast response and stability by making the control approach variable rather than fixed.
Solution Approach 2:
The control functionality is segmented into two distinct modes: ALC (Automatic Load Change) for rapid transitions and MPC (Model Predictive Control) for stable steady-state operation. This segmentation allows each control mode to be optimized for its specific purpose while the system switches between them as needed.
2Stability of the object's composition
If MPC controller is used to achieve stable steady-state operation, then system stability is improved, but load changing rate deteriorates
Solution Approach 1:
The control system dynamically switches between ALC mode (for rapid load changes) and MPC mode (for stable steady-state operation). The system adapts its control strategy based on operational requirements, enabling both fast response and stability by making the control approach variable rather than fixed.
Solution Approach 2:
The control functionality is segmented into two distinct modes: ALC (Automatic Load Change) for rapid transitions and MPC (Model Predictive Control) for stable steady-state operation. This segmentation allows each control mode to be optimized for its specific purpose while the system switches between them as needed.
3Manufacturing precision
If basic controllers are used to control process parameters, then manufacturing precision is improved, but device complexity deteriorates
Solution Approach 1:
The patent combines multiple control strategies (ALC and MPC) into a unified control system that manages process parameters. This merging allows the system to leverage the strengths of each control approach while reducing overall complexity through integrated management rather than separate independent control systems.
Solution Approach 2:
The control system is designed to perform multiple functions: it can operate in ALC mode for load changes, switch to MPC mode for steady-state stability, and manage multiple process parameters simultaneously. This multi-functionality reduces the need for separate specialized control systems for each function.
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 combination reduces system complexity and achieves stable steady-state operation along with high load changing rates, allowing for efficient adaptation to varying product demands and load cases in low-temperature air fractionation systems.
Implementation Method 1
compressed feed air is cooled down in a main heat exchanger, warmed up in the main heat exchanger
Implementation Method 2
low-temperature fractionation of air in a distillation column system
Data Source
AI summary
The process and the apparatus serve for the low-temperature fractionation of air in a distillation column system, which has at least one separating column. Feed air is compressed in a main air compressor. Compressed feed air is cooled in a main heat exchanger. Cooled feed air is introduced into the distillation column system. At least one product stream is drawn off from the distillation column system, heated in the main heat exchanger and drawn off as a gaseous end product. At least one process parameter is set by a basic controller. The control of the process parameter is set by a combination of an ALC control and an MPC controller. This involves the ALC control outputting a first target value to the MPC controller.