Antisurge Control for Turbo Compressors with Side Stream
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Solution Overview
Problem
Existing turbo compressor systems face inefficiencies due to inaccurate estimation of operating points, leading to inefficient antisurge control and potential surge phenomena, which can cause damage to the turbomachine and connected components.
Innovation Solution
The method involves estimating the temperature of the flow delivered by the upstream compressor stage using a non-dimensional performance map, allowing for accurate estimation of the temperature entering the downstream compressor stage, enabling effective antisurge control by recirculating fluid through antisurge valves when the operating point approaches the surge limit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional antisurge control methods are used without accurate temperature estimation, then the control system is simpler, but the accuracy of antisurge control deteriorates leading to potential surge phenomena
Solution Approach 1:
The patent introduces a non-dimensional performance map as an intermediary tool that correlates temperature, pressure, and flow rate parameters. This map serves as a mediator between the measured parameters (pressure and flow rate) and the unmeasured parameter (temperature), enabling accurate temperature estimation without direct temperature sensors in the compressor stages, thus improving measurement precision while avoiding excessive system complexity
Solution Approach 2:
The patent replaces direct physical temperature measurement (mechanical/thermal sensing) with a computational approach using non-dimensional performance maps and parameter correlations. This substitution eliminates the need for complex temperature sensing infrastructure while achieving accurate temperature estimation through mathematical relationships between pressure, flow rate, and temperature
2Power
If the compressor operating point approaches the surge limit, then the compressor can operate at higher pressure ratios, but the risk of surge phenomena increases causing potential damage
Solution Approach 1:
The patent implements a feedback control mechanism that continuously monitors pressure and flow rate parameters, estimates the operating point on the non-dimensional performance map, and adjusts the antisurge valve position accordingly. When the estimated operating point approaches the surge limit line, the system increases recirculation flow through the antisurge valve to maintain a safe distance from surge, thereby managing the trade-off between pressure ratio and surge risk
Solution Approach 2:
The patent applies preliminary anti-action by proactively increasing recirculation flow through the antisurge valve before the compressor actually reaches the surge condition. By continuously estimating the operating point and anticipating approach to the surge limit, the system takes preventive action to maintain safe operating margins, preventing surge phenomena before they can occur
Data Source
AI summary
A method is described for providing antisurge control in a system comprising a compressor having at least an upstream compressor stage, a downstream compressor stage and a side stream bringing flow into a flow passage between the upstream compressor stage and the downstream compressor stage. The method provides for estimating a temperature of a flow delivered by the upstream compressor stage using a non-dimensional performance map of the upstream compressor stage and further estimating a temperature of a flow entering the downstream compressor stage based on the mass flow and flow temperature of the flow delivered by the downstream compressor stage and the mass flow and the flow temperature of the side stream. The method further provides for performing antisurge control of the downstream compressor stage based on the temperature of the flow entering the downstream compressor stage.