Method for starting an argon separation column of an air separation device by cryogenic distillation and unit for implementing said method
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Solution Overview
Problem
Existing methods for starting an argon separation column in a cryogenic distillation air separation apparatus are inefficient, leading to prolonged startup times and significant argon losses due to uncontrolled venting of gases during the startup phase.
Innovation Solution
Implementing a control loop with an analyzer to regulate the degassing valve of the argon separation column, measuring nitrogen concentration to determine when to vent gas to the atmosphere or direct it to a deazotization column, minimizing argon losses and accelerating the startup process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the overhead gas from the argon separation column is continuously sent to the atmosphere during start-up, then the start-up process can proceed, but argon losses increase and start-up time is prolonged
Solution Approach 1:
The patent implements a feedback control system where an analyzer continuously measures the nitrogen content in the overhead gas of the argon separation column. Based on this real-time measurement, the control system automatically adjusts the position of the diversion valve to optimize the start-up process. When nitrogen content is high, gas is diverted to the atmosphere; when nitrogen content drops below a threshold, gas is redirected to the denitrogenation column, thereby minimizing argon losses while maintaining efficient start-up.
Solution Approach 2:
The patent changes the operational parameter of gas destination based on the measured nitrogen content. The diversion valve switches between two states: sending overhead gas to the atmosphere (when nitrogen content is high) and sending it to the denitrogenation column (when nitrogen content is low). This dynamic parameter change optimizes both start-up time and argon recovery.
2Loss of substance
If the overhead gas is diverted to the denitrogenation column too early during start-up, then argon losses are reduced, but nitrogen content in the argon product increases
Solution Approach 1:
The analyzer provides continuous feedback on the nitrogen content in the overhead gas, enabling the control system to make informed decisions about when to divert gas to the denitrogenation column. This feedback mechanism ensures that gas is only redirected when the nitrogen content has dropped to an acceptable level, thereby preventing contamination of the argon product while minimizing argon losses.
Solution Approach 2:
The patent replaces manual judgment and mechanical timing with an automated analytical measurement system. Instead of relying on fixed time intervals or operator experience to determine when to divert gas, the system uses an analyzer to objectively measure nitrogen content and automatically control the diversion valve, ensuring precise control over product quality.
3Productivity
If manual control of the diversion valve is used during start-up, then system complexity is reduced, but operational efficiency and precision decrease
Solution Approach 1:
The system performs self-service through automated control. The analyzer automatically measures nitrogen content, the control system automatically interprets the measurements, and the diversion valve automatically adjusts its position based on pre-programmed logic. This eliminates the need for continuous manual monitoring and intervention, significantly improving start-up efficiency and precision.
Solution Approach 2:
The patent substitutes manual mechanical control with an automated control system that uses analytical measurements to drive valve actuation. This replacement of human-operated mechanical systems with automated instrumented systems increases productivity while the added complexity is justified by the significant improvements in operational efficiency and product quality.
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
Significantly reduces argon losses and speeds up the startup phase by up to 25%, achieving rapid reduction of nitrogen and oxygen concentrations through controlled nitrogen management.
Implementation Method 1
an analyzer for measuring the nitrogen content at the top of the argon separation column and/or in a fluid drawn off at the top of the argon separation column
Implementation Method 2
Method for starting an argon separation column of an apparatus for separating air by cryogenic distillation
Data Source
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AI summary
An argon production unit by cryogenic distillation, adapted to be connected to a double air separation column consisting of a first and a second column (K1, K2) thermally connected to each other, comprises an argon separation column (K3) surmounted by a top condenser and a deazotation column (K4), means for withdrawing an argon-rich and nitrogen-depleted product (LAR) from the tank of the deazotation column, means for connecting the top of the argon separation column to the deazotation column, means for sending a top gas (13, 15) from the argon separation column to the atmosphere, means for withdrawing a nitrogen-rich fluid from the top of the deazotation column, an analyzer (AIC1,AIC2) for measuring the nitrogen content at the top of the argon separation column and means for opening and closing the means for connecting the top of the argon separation column to the deazotation column as a function of the nitrogen content detected by the analyzer.