Multi-Stage Turbo Compressor Blow-off System Surge Control
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Solution Overview
Problem
Multi-stage turbo compressors face challenges in rapid load and no-load transformation and bearing load reduction due to surge generation, with existing systems either causing excessive bearing load during pressure changes or requiring prolonged revolution reduction to avoid surge.
Innovation Solution
A blow-off system comprising multiple blow-off pipes and valves staged according to the compressor, with nozzles positioned at the valves to manage flow rates and prevent surge, including an on/off type first and second blow-off valve and nozzle configuration to control pressure and flow during loading and unloading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a relatively large valve is used to blow off at high flow rate to avoid surge, then surge is prevented, but momentary pressure increase applies much load to bearing during valve closure
Solution Approach 1:
The single blow-off valve is divided into multiple blow-off valves (first and second blow-off valves) positioned at different stages of the compressor. This segmentation allows the system to blow off air at multiple locations simultaneously, maintaining sufficient flow rate to prevent surge while distributing the load impact across multiple smaller valve closures rather than one large valve closure.
Solution Approach 2:
Different blow-off valves are positioned at different locations (stages) of the compressor to address local surge conditions. The first blow-off valve is positioned at one stage while the second blow-off valve is positioned at another stage, allowing targeted blow-off where surge is most likely to occur without unnecessarily increasing load at other locations.
2Force
If a relatively small valve is used to decrease blow-off quantity and reduce impact, then bearing load is reduced, but low speed surge occurs at low revolution
Solution Approach 1:
Multiple smaller blow-off valves are used instead of one large valve. Each valve handles a portion of the blow-off flow, allowing the system to maintain adequate total flow rate to prevent low-speed surge while each individual valve creates less impact load when closed.
Solution Approach 2:
Multiple blow-off valves operate simultaneously or in coordination to achieve the cumulative effect of a larger blow-off capacity. By combining the flow rates of multiple smaller valves, the system prevents surge without requiring any single valve to be large enough to cause excessive bearing load.
3Speed
If blow-off valve is closed rapidly to change to load state, then response time is reduced, but pressure increases momentously applying much load to bearing
Solution Approach 1:
The rapid closure of multiple smaller blow-off valves distributes the pressure increase event across several locations and time moments, rather than concentrating it in a single rapid closure event. This maintains fast response capability while reducing peak bearing load.
4Adaptability or versatility
If multiple nozzles are disposed at each stage of multi-stage compressor to prevent surge, then operating range is expanded, but device complexity increases
Solution Approach 1:
The compressor system is divided into multiple stages, with blow-off valves and nozzles positioned at specific stages rather than uniformly at all stages. This selective segmentation provides adequate surge prevention and operating range expansion while avoiding the complexity of equipping every single stage with full blow-off capability.
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 system enables rapid transformation between load and no-load states while minimizing bearing load impact, effectively preventing surge and ensuring safe operation by distributing the impact of pressure changes across multiple stages.
Implementation Method 1
a plurality of nozzles disposed at the front or back sides of the plurality of blow-off valves, thereby preventing the generation of surge
Data Source
Figure 1~2
Figure 3
AI summary
The present invention relates to a blow-off system for a multi-stage turbo compressor that includes a plurality of blow-off pipes disposed according to respective stages of the multi-stage turbo compressor; a plurality of blow-off valves disposed correspondingly to the plurality of blow-off pipes; and a plurality of nozzles disposed at the front or back sides of the plurality of blow-off valves and adapted to prevent the generation of surge.