Gas Turbine Compressor Bypass Line for Surge Prevention
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Solution Overview
Problem
In gas turbine plants, the supply of steam between the compressor outlet and turbine inlet can lead to surging in the compressor due to increased pressure, especially when fuel with a low calorific value is used, which requires a higher fuel flow rate to maintain output, exacerbating the issue.
Innovation Solution
A gas turbine plant configuration with a bypass line and adjustment device to manage the air flow and fluid supply, allowing for the bypass of compressed air from the low-pressure stage around the high-pressure stage and the controlled supply of steam or water with different enthalpies to the connection line between the compressor and turbine, thereby regulating the pressure and flow rates to prevent surging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If steam is supplied between the outlet of the compressor and the inlet of the turbine, then the output of the turbine is increased, but the pressure at the outlet of the compressor increases causing surging in the compressor
Solution Approach 1:
The compressor is divided into two independent stages: a low-pressure stage and a high-pressure stage. This segmentation allows the system to independently control air flow through each stage, preventing surging in the low-pressure stage while maintaining high turbine output through the high-pressure stage.
Solution Approach 2:
A bypass line is introduced as an intermediary pathway that allows air compressed in the low-pressure stage to bypass the high-pressure stage and be supplied to the combustor. This mediator enables the system to maintain stable operation by providing an alternative flow path that prevents pressure buildup and surging.
2Power
If fuel having a low calorific value is supplied to the combustor, then the fuel flow rate required to obtain the same output is greater, but this increases the pressure at the outlet of the compressor causing surging
Solution Approach 1:
By segmenting the compressor into low-pressure and high-pressure stages with independent flow control, the system can accommodate variable fuel flow rates required for low calorific value fuels without causing surging. The low-pressure stage can operate independently to maintain stable air flow regardless of fuel characteristics.
Solution Approach 2:
The bypass line with adjustment device provides dynamic control capability, allowing the system to adapt air flow rates in real-time based on fuel characteristics and operating conditions. This dynamic adjustment prevents surging when using fuels with varying calorific values.
3Productivity
If the flow rate of fluid supplied between the outlet of the compressor and the inlet of the turbine is increased, then the output of the turbine is increased, but the pressure at the outlet of the compressor increases causing surging
Solution Approach 1:
The two-stage compressor configuration allows independent optimization of flow rates for each stage. The low-pressure stage can be designed for high flow rate operation to increase turbine productivity, while the high-pressure stage maintains stable operation within safe pressure limits, preventing surging.
Solution Approach 2:
The bypass line acts as a mediator that enables high flow rate operation by allowing excess air from the low-pressure stage to bypass the high-pressure stage. This intermediary pathway decouples the flow rate increase from pressure increase, enabling productivity improvement without compromising 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 configuration effectively suppresses compressor surging by adjusting the fluid supply and air bypass, allowing for increased turbine output while maintaining efficiency and preventing pressure fluctuations.
Implementation Method 1
a compressor high-pressure stage for further compressing the air compressed at the compressor low-pressure stage
Implementation Method 2
a plurality of supply lines configured to supply steam or water having different enthalpies to the connection line
Implementation Method 3
a combustor configured to mix and combust the air compressed by the compressor with fuel
Implementation Method 4
a turbine configured to be driven by combustion gas generated in the combustor
Data Source
AI summary
A gas turbine plant includes a connection line configured to connect an outlet of a compressor high-pressure stage and an inlet of a turbine via a combustor, a bypass line configured to cause some or all of air compressed at a compressor low-pressure stage to bypass the compressor high-pressure stage and to be supplied to the connection line, and an adjustment device configured to adjust a flow rate of the air flowing through the bypass line. A plurality of types of fluid are supplied to the connection line in addition to the air compressed by the compressor, and during operation of the gas turbine plant, supply of at least one type of fluid of the plurality of types of fluid to the connection line is stopped according to an operating state of the gas turbine plant.