Gas Turbine Bleed Air Control for Stable Low-Output Operation
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Solution Overview
Problem
Existing gas turbine systems face instability when reducing output, as they struggle to maintain stable operation and drive auxiliary turbines with bled air effectively.
Innovation Solution
A gas turbine system with a bleed line, exhaust line, and adjustment valves to control the flow rates of bleed air, allowing for stable operation even at reduced outputs by adjusting the bleed amount, inflow, and exhaust amounts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the output of the gas turbine is reduced by bleeding air from the gas turbine, then the power generation output can be decreased to match lower demand, but the stable operation of the gas turbine and auxiliary turbine becomes difficult to maintain
Solution Approach 1:
The bleed air flow path is segmented into multiple controlled sections with separate adjustment valves. The bleed line includes a bleed amount adjustment valve near the gas turbine, an inflow amount adjustment valve before the auxiliary turbine, and an exhaust amount adjustment valve after the auxiliary turbine. This segmentation allows independent control of each flow section, enabling the system to maintain stable operation while reducing overall output by adjusting individual valve positions rather than uniformly reducing all flows.
Solution Approach 2:
The system employs dynamic adjustment of multiple valves to control bleed air flow rates in real-time. The bleed amount adjustment valve, inflow amount adjustment valve, and exhaust amount adjustment valve can be independently positioned at different opening degrees based on operational requirements. This dynamic control capability allows the system to adapt to varying power demands while maintaining stable combustion and turbine operation, resolving the contradiction between output reduction and operational stability.
2Productivity
If the flow rate of compressed air flowing into the combustor is reduced below the minimum intake flow rate, then the power output can be reduced further, but stable combustion of fuel becomes difficult to maintain
Solution Approach 1:
The exhaust line acts as an intermediary pathway that allows bleed air to be exhausted independently from the main combustion process. By providing this separate exhaust path with its own adjustment valve, the system can reduce the amount of air entering the combustor below the minimum intake flow rate while maintaining stable combustion. The exhaust line serves as a mediator that decouples the combustion stability requirement from the power output requirement, enabling low-power operation without compromising combustion stability.
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
Enables stable operation of the gas turbine and auxiliary turbine by maintaining constant bleed air flow rates, ensuring stable combustion and efficient power generation even at reduced outputs.
Implementation Method 1
a compressor that is configured to compress air
Implementation Method 2
a combustor that is configured to generate combustion gas by combusting fuel in compressed air
Implementation Method 3
a turbine that is driven by the combustion gas
Implementation Method 4
an auxiliary turbine that is connected to the bleed line and driven by the bleed air which has flowed through the bleed line
Data Source
AI summary
A gas turbine system includes a gas turbine, a bleed line through which a part of compressed air generated by a compressor of the gas turbine is bled from the gas turbine as bleed air, an exhaust line that branches off from a middle of the bleed line, an auxiliary turbine that is driven by the bleed air which has flowed through the bleed line, a bleed amount adjustment valve that is provided in the bleed line and that is configured to adjust the flow rate of the bleed air bled from the gas turbine, an inflow amount adjustment valve that is provided in the bleed line and that is configured to adjust the flow rate of the bleed air flowing into the auxiliary turbine, and an exhaust amount adjustment valve that is provided in the exhaust line and that is configured to adjust the flow rate of the bleed air exhausted from the bleed line.