Sequential Combustor Firing Temperature Control at Low Load
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gas turbine systems with sequential combustion face limitations in their lower load range due to increased carbon monoxide emissions, requiring a method to maintain operational limits while reducing air flow and controlling firing temperatures during low part load operations.
Innovation Solution
A gas turbine controller determines a limiting firing temperature or schedule for operative burners in the second combustor, based on parameters like inlet guide vane position and operational limits, to keep the system within acceptable operational ranges by switching off multiple burners and adjusting air flow, including external cooling air provision during low part load modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If multiple burners are switched off to reduce carbon monoxide emissions during low part load operation, then emissions compliance is improved, but the operational range and flexibility of the gas turbine system deteriorates
Solution Approach 1:
The system dynamically adjusts the number of operative burners and their firing temperatures based on real-time load conditions and emissions constraints. The controller continuously monitors operational parameters and switches burners on/off or adjusts fuel flow to maintain compliance while maximizing operational flexibility across varying load conditions.
Solution Approach 2:
The invention changes operational parameters including the number of active burners, fuel flow rates, and firing temperatures to maintain carbon monoxide emissions within acceptable limits. By varying these parameters dynamically, the system expands its operational range while meeting emissions requirements at different load levels.
2Reliability
If air flow through the hot gas path is reduced via closing compressor inlet guide vanes to keep SEV burners within operational range, then burner operation stability is improved, but the system's load range and efficiency deteriorates
Solution Approach 1:
The system performs preliminary actions by pre-cooling the hot gas path using external cooling air before introducing fuel to the SEV burners. This pre-cooling ensures that burners operate within stable temperature ranges even when main air flow is reduced, allowing the system to maintain reliability while extending the usable load range.
Solution Approach 2:
External cooling air acts as an intermediary substance that mediates between the reduced main air flow and the SEV burners. This cooling air provides the necessary thermal management to keep burners within operational limits without requiring proportional reduction in main air flow, thereby preserving load range and efficiency.
3Use of energy by moving object
If firing temperature is increased to maintain efficient combustion during low part load mode, then energy efficiency is improved, but operational limits and component durability deteriorate
Solution Approach 1:
The combustion system is segmented into multiple independent burners, allowing selective operation of SEV burners in addition to main burners. This segmentation enables efficient combustion at low loads by activating only the necessary number of burners, while distributing thermal loads to prevent any single component from exceeding durability limits.
Solution Approach 2:
External cooling air is introduced as a preliminary action before SEV burners operate at high firing temperatures. This pre-cooling of the hot gas path allows burners to operate at efficient high temperatures without causing excessive thermal stress on downstream components, thereby maintaining both efficiency and 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 approach enhances the precision of firing temperature control, allows for more burners to be switched off, increases operational range by 5-10%, reduces fuel consumption, and improves environmental compliance by minimizing pollutant emissions and greenhouse gas output.
Implementation Method 1
A gas turbine system includes a gas turbine controller (46) that determines based on an operational parameter of the gas turbine system (10), a limiting firing temperature for operative burners (28) of a second combustor (18)
Data Source
AI summary
A method for operating a gas turbine system includes utilizing a gas turbine controller to determine a schedule for a firing temperature for operative burners of a second combustor located downstream of a first combustor when the gas turbine system is operating in a low part load mode. During the low part load mode, multiple burners for the second combustor are switched-off. Further, the schedule is determined based on a position of inlet guide vanes of a compressor of the gas turbine system located upstream of both the first and second combustors. The method also includes controlling the firing temperature of the operative burners utilizing the schedule during the low part load mode to keep the gas turbine system within relevant operational limits of the gas turbine system.