Multi-Stage Flamesheet Combustor Fuel Staging Control
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Solution Overview
Problem
Gas turbine combustion systems face instability and high emissions at lower load settings, leading to inefficient operation and premature hardware degradation, as they are typically staged for high load conditions, resulting in wasted fuel and additional engine cycles when operating at part-load or shut down.
Innovation Solution
A method of operating a gas turbine combustor that involves multiple fuel stages and modes of operation, including the use of a pilot nozzle, pilot tune injectors, and main fuel injectors, with fuel flow modulation to maintain stability and low emissions across varying load conditions, utilizing a system with four fuel circuits and temperature sensors to transition between operational modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If combustion systems are staged for high load settings, then combustion efficiency is improved at high load, but combustion stability and emissions performance deteriorate at lower load settings
Solution Approach 1:
The combustion system is divided into multiple independently controllable fuel stages (first stage, second stage, third stage) with distinct injector groups. Each stage can be activated or deactivated based on load conditions, allowing the system to optimize combustion characteristics for both high and low load operations. The first stage uses a first group of injectors, the second stage adds a second group, and the third stage adds a third group, enabling progressive fuel addition tailored to demand.
Solution Approach 2:
The combustion system dynamically adjusts the number of active fuel injector groups based on real-time load conditions. At high load, all three stages are active with all injector groups operating. At lower load, only the necessary first and second stages are active, with the third stage deactivated. This dynamic reconfiguration maintains optimal combustion stability and emissions performance across the entire operating range.
2Power
If combustion systems are staged for high load settings, then power output is maximized, but fuel consumption increases and operating costs rise at part-load conditions
Solution Approach 1:
The system applies partial action by activating only the necessary fuel stages and injector groups required for the current load demand. At part-load conditions, only the first and second stages are active with selective injector groups, rather than operating all injectors at reduced capacity. This partial activation reduces fuel consumption and operating costs while maintaining adequate power output.
3Loss of energy
If combustion systems operate at lower load settings, then fuel consumption is reduced, but combustion instability increases and emissions performance deteriorates
Solution Approach 1:
Different injector groups are activated in specific spatial locations based on load conditions. The first group of injectors operates at all loads, the second group activates at medium loads, and the third group activates at high loads. This localized activation ensures that the combustion zone maintains optimal fuel-air mixing and flame stability characteristics even at lower overall fuel consumption levels, thereby controlling emissions.
4Loss of energy
If combustion systems operate at lower load settings, then operating costs are reduced, but hardware degradation accelerates due to additional engine cycles
Solution Approach 1:
The system dynamically adapts its operational configuration to match load demand, activating only the minimum necessary fuel stages and injector groups. This prevents unnecessary cyclic operation of all hardware components and reduces wear on injectors and combustion chamber elements during part-load operation, thereby extending hardware life while maintaining cost-effective operation.
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 combustion stability and reduces emissions at both full and part-load conditions, allowing for efficient operation at lower loads without the need for shutdown, thereby saving fuel and extending engine hardware life.
Implementation Method 1
supplying fuel to a pilot nozzle and igniting the fuel to form a pilot flame
Implementation Method 2
The fuel/air mixture then reverses direction and enters the combustion liner 304 where it is ignited and combusted by the pilot flame
Implementation Method 3
Main fuel injectors 306 are positioned radially outward of the combustion liner 304 and are designed to provide a fuel supply to mix with compressed air
Data Source
AI summary
The present invention discloses a novel way of controlling a gas turbine engine using detected temperatures and detected turbine rotor speed. An operating system provides a series of operating modes for a gas turbine combustor through which fuel is staged to gradually increase engine power, yet harmful emissions, such as carbon monoxide, are kept within acceptable levels.