Non-steam-driven ejectors for steam turbine cooling
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Solution Overview
Problem
Existing steam turbine forced air cooling systems face limitations in cooling efficiency due to the capacity and suction capability of vacuum pumps, leading to prolonged cooling times and wasteful use of thermal energy when using steam-driven ejectors, which hinders quick shutdown and startup of power plants.
Innovation Solution
A steam turbine forced air cooling system utilizing non-steam-driven ejectors, such as compressed air or nitrogen-driven ejectors, installed separately from existing vacuum pumps, to increase cooling air flow and avoid the need for auxiliary steam and air coolers, allowing for efficient cooling without wasting thermal energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the existing vacuum pump is used to suck cooling air into the steam turbine, then the cooling system can be implemented using existing equipment, but the amount of cooling air introduced is limited by the vacuum pump's capacity and suction capability
Solution Approach 1:
The patent combines multiple ejectors with different capacities (start-up ejector and normal operation ejector) to work together with the vacuum pump, creating a hybrid system that overcomes the limited suction capability of the vacuum pump alone and enables sufficient cooling air flow for effective steam turbine cooling
Solution Approach 2:
The ejectors are designed to serve multiple functions: the start-up ejector handles both condenser evacuation and cooling air introduction, while the normal operation ejector manages ongoing cooling requirements, allowing a single equipment type to address varying cooling demands across different operational phases
2Productivity
If steam-driven ejectors are used to increase cooling air flow, then the cooling capability is improved, but auxiliary steam is required and thermal energy is wasted when the boiler is not operated
Solution Approach 1:
The patent changes the drive mechanism parameter from steam-driven to electrically-driven compressors, eliminating the dependency on auxiliary steam and allowing the cooling system to operate independently of boiler status, thereby preventing thermal energy waste during plant start-up or shutdown phases
Solution Approach 2:
The compressor system is designed to independently provide both the drive gas for ejectors and the cooling air flow without requiring external steam resources, making the cooling system self-sufficient and capable of operation during all plant phases including start-up and shutdown
3Stability of the object's composition
If the cooling time is extended to allow natural heat-release, then the cooling is gentle and avoids thermal stress, but the time required for shutdown and startup operations increases significantly
Solution Approach 1:
The patent implements a dynamic cooling system that can adjust cooling intensity based on operational requirements, using controllable ejectors and compressors to modulate cooling air flow, thereby enabling both gentle cooling when needed and accelerated cooling when operational time constraints require faster shutdown or startup
4Reliability
If air coolers are installed to cool the high-temperature air before it enters the vacuum pump, then the vacuum pump can handle the cooling air, but the delivery interval and installation process increase, resulting in more time-consuming installation
Solution Approach 1:
The patent extracts the air cooling function from the vacuum pump system by using ejectors that can handle high-temperature air directly, eliminating the need for separate air coolers and their associated cooling water piping, thereby simplifying the system and reducing installation time while maintaining vacuum pump reliability
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
This solution enables faster cooling of steam turbines, reduces energy waste, and provides a cost-effective and simple configuration for improved cooling efficiency, ensuring stable electric power supply and minimizing installation complexities.
Implementation Method 1
A steam turbine forced air cooling system utilizing non-steam-driven ejectors, such as compressed air or nitrogen-driven ejectors
Implementation Method 2
the steam turbine is cooled with the use of the outside air so as not to cause heat stress or thermal strain
Data Source
AI summary
The invention offers a steam turbine forced air cooling system, its method, and a steam turbine provided with the system, the system being of an inexpensive and simple device configuration and improving a cooling effect by the use of an easy-to-get device.Suction is applied to the steam introduction side of an HP turbine 4 or an IP turbine 9 by the use of cooling air suction ejectors 27, 28 which use a compressed medium other than steam as a drive source. The cooling air is then introduced from the steam exhaust portion of the steam turbine into the inside of the steam turbine and is discharged from the ejectors 27, 28 to the atmosphere.