Sequential Combustion Gas Turbine Part-Load CO Emission Control
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Solution Overview
Problem
Gas turbines with sequential combustion face challenges in reducing CO emissions and pressure drop during part-load operation without increasing flashback risk, as existing solutions either stress the low-pressure turbine or are limited by temperature constraints.
Innovation Solution
The method involves varying the second combustor inlet temperature by adjusting the dilution air flow and fuel-to-air ratio in the first combustor, using a mixer to control the hot gas temperature, and employing fuels with short ignition times, such as those with high H2 content, to manage CO emissions and pressure drop effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the second combustor is started at the highest possible load, then CO emissions are reduced, but the hot gas temperature for the first combustor must be maintained within limits imposed by the high pressure turbine lifetime
Solution Approach 1:
The invention changes the operational parameters of the sequential combustion system by dynamically adjusting the temperature of hot gas from the first combustor to the second combustor based on load conditions. At part-load operation, the hot gas temperature is increased to maintain efficient combustion and reduce CO emissions, while at base-load, the temperature is reduced to protect turbine components. This parameter adaptation resolves the contradiction between emission reduction and temperature management.
2Object-generated harmful factors
If the hot gas temperature from the first combustor is increased for part-load operation, then CO emissions are reduced, but this increases flashback risk in the second combustor
Solution Approach 1:
The invention dynamically adjusts the hot gas temperature parameter based on operational load and fuel composition. When operating at part-load with fuels having longer ignition times, the system increases the hot gas temperature to maintain combustion efficiency and reduce CO emissions. The control system monitors fuel properties and adjusts temperature accordingly, allowing higher temperatures at part-load without excessive flashback risk, while maintaining safety at base-load operation.
3Temperature
If dilution air is injected into the hot gas channel to cool the gas, then the second combustor inlet temperature is reduced, but this increases the pressure drop and reduces performance
Solution Approach 1:
The invention optimizes the dilution air injection parameter by controlling both the temperature and mass flow rate of dilution air based on operational conditions. Instead of using excessive dilution air that would cause large pressure drops, the system precisely adjusts the dilution air flow to achieve the required temperature reduction with minimal impact on performance. This optimized parameter control reduces the energy loss associated with dilution air injection while still protecting the turbine from excessive temperatures.
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 significantly reduces CO emissions and pressure drop during part-load operation while maintaining engine performance and avoiding flashback risks, allowing for increased hot gas temperature variations and flexible fuel compositions without compromising engine reliability.
Implementation Method 1
a first combustor (14, 17) with a first combustion chamber and first burners (17), which receives compressed air from the compressor (13)
Implementation Method 2
a second combustor (15, 19) with a second combustion chamber and second burners (20), which receives hot gas from the first combustor (14, 17)
Implementation Method 3
The hot gas from the second combustor (15, 19) enters the turbine (16) to do work
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention discloses a method for operating a gas turbine (10) with sequential combustion (14, 15, 17, 19), which gas turbine (10) comprises a compressor (13), a first combustor (14, 17) with a first combustion chamber (14) and first burners (17), which receives compressed air from the compressor (13), a second combustor (15, 19) with a second combustion chamber (15) and second burners (19), which receives hot gas from the first combustor (14, 17) with a predetermined second combustor inlet temperature, and a turbine (16), which receives hot gas from the second combustor (15, 19). The CO emission for part-load operation is reduced by reducing the second combustor inlet temperature for base-load operation of the gas turbine (10), and increasing the second combustor inlet temperature when decreasing the gas turbine load (RLGT) from base-load to part-load.