Compressor Surge Control Using Dewpoint-Based Steam Adaptation
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Solution Overview
Problem
Existing surge limit controllers in compressors are slow to react to changes in process gas composition, leading to unstable operation due to the reliance on gas chromatographs, which are costly and time-consuming.
Innovation Solution
Determine the steam proportion of the process gas using a dewpoint mirror hygrometer and adapt the control line based on steam proportion and optionally temperature, allowing rapid adjustment of the control characteristic curve within milliseconds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a gas chromatograph is used to determine gas composition, then measurement precision is improved, but response time increases and cost increases
Solution Approach 1:
The patent replaces the expensive gas chromatograph with a dewpoint mirror hygrometer that provides sufficient measurement precision for compressor surge limit control at lower cost and with much faster response time. The dewpoint measurement directly yields steam proportion without requiring complex gas composition analysis.
Solution Approach 2:
The patent substitutes the mechanical/chemical analysis method (gas chromatography) with a physical measurement method (dewpoint mirror hygrometry). This replacement achieves the same control objective (determining steam proportion) through a simpler, faster physical measurement rather than complex chemical separation and detection.
2Measurement precision
If a gas chromatograph is used to determine gas composition, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts only the essential measurement function needed for compressor control (determining steam proportion) from the complex gas chromatograph system. By using a dewpoint mirror hygrometer, the system retains the necessary measurement capability while removing unnecessary complexity associated with full gas composition analysis.
Solution Approach 2:
The patent replaces the complex and expensive gas chromatograph with a simpler, more affordable dewpoint mirror hygrometer that provides adequate measurement precision for the control application, thereby reducing both device complexity and cost.
3Stability of the object's composition
If the control line is fixed away from the surge limit, then compressor stability is improved, but adaptability to changing gas composition deteriorates
Solution Approach 1:
The patent transforms the fixed control line into a dynamic control characteristic that automatically adapts to changing steam proportions in the process gas. The surge limit controller continuously adjusts the control line position based on real-time dewpoint measurements, enabling the system to maintain stability across varying gas compositions.
Solution Approach 2:
The patent implements a feedback mechanism where dewpoint measurements of the process gas are continuously fed back to the surge limit controller. This feedback loop enables the control system to detect changes in steam proportion and automatically adjust the control line position to maintain adequate distance from the surge limit, thereby preserving both stability and adaptability.
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
Ensures stable compressor operation by dynamically adapting the control line to steam proportion and temperature changes, maintaining a safe distance from the surge limit within seconds.
Implementation Method 1
the dewpoint of the process gas is measured in particular with the help of a dewpoint mirror hygrometer, and the proportion of steam is determined dependent on the dew point
Data Source
AI summary
A method for operating a compressor. A flow rate of the process gas through the compressor is determined. Dependent on a measured inlet pressure of the compressor and a measured outlet pressure of the compressor, a delivery head of the compressor is determined. A surge limit controller, dependent on the flow rate and dependent on the delivery head determines a control variable for a control element interacting with the compressor such that the compressor is operated along a control line, which has a defined distance from the surge limit of the compressor. A proportion of steam of the process gas is determined, and the control line, along which the compressor is operated, is adapted dependent on the proportion of steam.