Sequential Combustion Gas Turbine Part Load Emissions Control
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Solution Overview
Problem
Gas turbines with sequential combustion experience high CO emissions at low part loads due to self-ignition and short residence time in the second combustor, limiting their operational flexibility and efficiency.
Innovation Solution
Controlling the position of variable compressor inlet guide vanes based on burner exhaust temperature to manage fuel flow and prevent excessive temperatures, while strategically activating or deactivating burners in the second combustor to maintain optimal operating conditions and minimize CO emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the second combustor is ignited at low part load with minimum fuel flow, then the gas turbine can operate at low load, but high CO emissions occur due to short residence time and low reaction speed
Solution Approach 1:
The patent changes the air-fuel ratio parameter in the second combustor from the conventional high value (lean combustion) to a lower value by controlling the air fuel ratio of operative burners. This parameter change increases the reaction speed and residence time effectiveness, thereby reducing CO emissions while maintaining low part load operation capability
Solution Approach 2:
The patent dynamically adjusts the number of operative burners in the second combustor based on load conditions. At low part load, fewer burners are operated with optimized air-fuel ratios, while at higher loads more burners are activated. This dynamic configuration allows the system to maintain low CO emissions across different operating conditions
2Adaptability or versatility
If the variable compressor inlet guide vanes are closed to enable low part load operation, then flexibility is improved, but CO emissions increase due to self-ignition and short residence time
Solution Approach 1:
The patent implements feedback control by monitoring the air-fuel ratio and burner exhaust temperature, and adjusting the operation of the second combustor accordingly. The system continuously adapts the number of operative burners and their air-fuel ratios based on real-time operating conditions, ensuring low CO emissions while maintaining operational flexibility across the full load range
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 approach reduces CO emissions, extends component lifespan, and ensures efficient operation of subsequent steam cycles or waste heat processes by maintaining burner temperatures within safe limits and optimizing fuel distribution.
Implementation Method 1
a compressor for compressing air
Implementation Method 2
a first combustor which is connected downstream to the compressor and the hot gases of which first combustor are admitted to the first turbine
Implementation Method 3
a first turbine, referred to as the high-pressure turbine, is exposed to admission of hot gases
Implementation Method 4
a second combustor which is connected downstream to the first turbine and the hot gases of which are admitted to the second turbine
Implementation Method 5
a second turbine, which is referred to as the low-pressure turbine, is exposed to admission of these hot gases
Data Source
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AI summary
In a method for the low-CO emissions part load operation of a gas turbine with sequential combustion, the opening of the row of variable compressor inlet guide vanes (14) is controlled depending on the temperatures of the operative burners (9) of the second combustor (15) and simultaneously the number of operative burners is kept at a minimum. This leads to low CO emissions at partial load of the gas turbine.