Can-Annular Combustor Segmentation for Stable Low-Load Operation
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Solution Overview
Problem
Current gas turbine combustion systems face challenges in achieving stable combustion and reducing NOx and CO emissions, especially at lower load conditions, due to the lack of adjustability and optimal combustion for each premixed burner load and type of fuel in annular designs.
Innovation Solution
The implementation of a sequential combustion system using can-combustors with premixed burners, conical swirlers, and mixing tubes, along with optimized fuel injection and cooling systems, allows for independent control of combustion dynamics and emissions across various load conditions, enhancing serviceability and reducing pollution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If annular combustion chamber design is used, then compact structure is achieved, but stable combustion at lower load conditions deteriorates
Solution Approach 1:
The annular combustion chamber is segmented into multiple individual tubular units (can-combustors) arranged circumferentially around the rotor shaft. Each can-combustor operates as an independent combustion zone with its own premixed burners, allowing individual control of combustion parameters. This segmentation enables stable combustion at lower loads by isolating combustion zones and preventing flow interference between adjacent burners.
2Object-generated harmful factors
If multiple injectors and swirlers are added for fuel staging, then emissions control improves, but device complexity increases
Solution Approach 1:
The combustion system is divided into multiple can-combustors, each equipped with its own fuel injection system and swirler. This segmentation allows independent fuel staging control in each can-combustor, enabling effective NOx and CO emissions reduction through localized optimization without requiring a single complex centralized injection system.
Solution Approach 2:
Fuel flow to each injector is controlled independently to allow for fuel staging throughout various load conditions. The system dynamically adjusts fuel distribution across multiple can-combustors based on operating conditions, maintaining optimal combustion and emissions control across the entire load range.
3Reliability
If flow reversal and recirculation zones are created in the liner, then combustion stability improves, but pressure loss increases
Solution Approach 1:
The combustion chamber is divided into multiple can-combustors with individual flow paths. Each can-combustor creates its own recirculation zones independently, providing combustion stability without requiring strong recirculation zones that would cause significant pressure drops in a single large annular chamber. The segmented design distributes the recirculation requirements across multiple smaller zones.
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 design achieves stable combustion and reduced emissions by allowing for optimal operation of premixed burners across the entire load range, improving serviceability, reducing development costs, and extending turbine part lifetime while minimizing CO emissions.
Implementation Method 1
a conical swirler provided upstream of a mixing tube, the conical swirler having tangential air inlet slots
Implementation Method 2
at least one can-combustor with at least one premixed burner
Implementation Method 3
a first main-combustor which is connected downstream to the compressor and in which fuel combustion takes place
Implementation Method 4
cooling channels in the can-combustors
Data Source
Figure 1~1a
Figure 2~2a
Figure 3~3b
AI summary
The invention concerns a gas turbine system, comprising a compressor, at least one combustion chamber (10), and eventually a secondary combustion chamber, for generating working gas. An intermediate turbine may be placed between two combustion chambers. The combustion chamber (15) consists of an individual can-combustor (120) or a number of can-combustors (120) arranged in an annular can-architecture. The can-combustor (120) comprises a number of premixed burners (10) arranged uniformly or divided at least in two groups. One or more groups of the premixed burners (10) may be shifted along the combustor axis with respect to another group, and may also be inclined with respect to the combustor axis. Optional Helmholtz dampers (16) reduce combustion pulsations. Ignition of the mixture starts at the premixed burner outlet. The flame is stabilized in the region of the premixed burner outlet by means of a backflow zone.