Rectification Column Temperature Control Under Pressure Fluctuations
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Solution Overview
Problem
Existing rectification column control methods are inadequate in maintaining the quality of separation under pressure fluctuations and changes in hydraulic loading, often leading to instability and inaccurate control due to reliance on pressure measurements, which are prone to errors and require additional sensors.
Innovation Solution
A method for controlling a rectification column using temperature measurements to adjust the mass fractions of components A and B in product streams, utilizing a calculated control temperature setpoint based on reference temperatures and a factor F, which remains constant under varying pressures, allowing for precise control through adjustments in heating, reflux flow, and product stream flows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure measurements are used to compensate for pressure fluctuations in rectification column control, then control accuracy under pressure changes can be improved, but device complexity increases due to additional pressure sensors and measurement systems
Solution Approach 1:
The invention extracts the pressure compensation function from the control temperature measurement system by using a separate, dedicated pressure sensor that provides pressure data independently. This allows the temperature measurement to focus solely on composition information while the pressure sensor handles pressure fluctuations, eliminating the need for complex pressure-compensated temperature calculations and reducing overall system complexity.
Solution Approach 2:
The invention introduces an intermediary pressure sensor that mediates between the pressure fluctuations and the control system. The pressure sensor acts as a separate information source that allows the controller to distinguish between temperature changes due to composition changes and those due to pressure changes, enabling accurate control without complicating the temperature measurement system.
2Reliability
If pressure-compensated temperature control is implemented, then control reliability under pressure fluctuations can be improved, but device complexity and susceptibility to malfunctions increase due to additional pressure sensors
Solution Approach 1:
The invention applies self-service by using the existing pressure sensor already present in the rectification column system for control purposes. Instead of adding complex pressure-compensated temperature measurement systems, the invention utilizes the available pressure information in conjunction with temperature measurements, allowing the system to serve its own control needs without additional complex instrumentation.
3Measurement precision
If multiple temperature sensors are used for differential temperature measurement, then pressure compensation can be achieved, but device complexity and cost increase
Solution Approach 1:
The invention applies universality by making the single temperature sensor serve multiple functions: it provides both the process temperature information needed for composition control and, in combination with pressure data, enables pressure compensation. This eliminates the need for multiple temperature sensors or differential temperature measurement systems while achieving the same control objectives.
4Adaptability or versatility
If pressure measurements are integrated into the control system, then adaptability to pressure changes can be improved, but ease of operation and maintenance deteriorate due to additional measurement points requiring calibration
Solution Approach 1:
The invention merges the pressure compensation function with the existing temperature control system by using a single integrated controller that processes both temperature and pressure data. This combination allows the system to adapt to pressure changes while maintaining a simple, unified control architecture that does not require separate calibration procedures for multiple measurement systems.
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
The method ensures consistent separation quality of components A and B by stabilizing control despite pressure changes, improving accuracy and reliability without the need for additional pressure sensors, thus maintaining desired mass fractions in product streams.
Implementation Method 1
heating of the column bottom (130) by the evaporator (200)
Implementation Method 2
heating of the column bottom (130) by the evaporator (200)
Implementation Method 3
a condenser (300) for partially condensing the gaseous overhead fraction (A1)
Implementation Method 4
continuous rectification in industrial production... transfer B into the bottom of the column... and transfer A into the top of the column
Data Source
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AI summary
The present invention provides a method for operating a rectification column (1000) for separating a mixture (S) containing a component A and a component B having a boiling point higher than that of the component A at an operating pressure of the rectification column (1000) which is lower than ambient pressure, wherein the method comprises a step for controlling the mass fraction of the component B in the product stream of the component A (P1) to a value within a first target range from 0.1% to 5.0% and the mass fraction of the component A in the product stream of the component B (P2) to a value within a second target range from 0.1% to 5.0%, wherein the control is carried out as a function of a controlling temperature (TC) for which a setpoint TCsetpoint is calculated according to the equation TCsetpoint =T2 + F • (T1 − T2), where F is a factor which is in the range from 0.1 to 0.9 and T1 and T2 are reference temperatures, wherein in the case of a deviation in the measured control temperature (TC) from its setpoint TCsetpoint being found the control temperature (TC) is readjusted to the setpoint TCsetpoint by varying one or more of the following actuating variables: (i) heating of the column bottom (130) by the evaporator (200), (ii) the mass flow ṁA42 of the reflux (A42) fed back into the rectification column, (iii) the mass flow ṁP2 of the product stream P2 and (iv) the mass flow ṁP1 of the product stream P1.