Axially Staged Gas Turbine Combustor Premixer

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Solution Overview

Problem

Gas turbine combustion systems do not completely burn fuel particles, leading to higher emissions of nitrous oxide (NOx) and carbon monoxide (CO), which reduces energy output and increases environmental impact.

Innovation Solution

An axially staged combustion system is implemented, featuring a combustion liner with a premixer that includes channels and fuel injectors positioned to mix fuel and air radially outward of the liner, imparting swirl and directing the mixture radially inward for complete burning in a second combustion stage, reducing emissions and enhancing energy output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If a typical combustor is used, then the structure is simple, but fuel particles are not completely burned leading to higher emissions

Engineering Contradiction:
ImproveemissionsVSAvoidcombustor structure
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The combustor is divided into multiple stages: a first combustion chamber for initial combustion and a second combustion stage with a premixer for completing fuel particle combustion. This segmentation allows each stage to perform a specific function, ensuring complete burning while managing complexity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A premixer is positioned between the combustion liner and transition duct to pre-mix fuel and air before the second combustion stage. This preliminary mixing action ensures proper fuel-air preparation that enables complete combustion of fuel particles in the second stage, reducing emissions

Inventive Principle:
Principle #10Preliminary action

2Power

If fuel is not completely burned, then energy output is reduced, but the combustion process is simpler

Engineering Contradiction:
Improveenergy outputVSAvoidcombustion system
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The combustion system is segmented into two stages: first combustion chamber for initial energy release and second combustion stage with premixer for completing fuel particle combustion and maximizing energy extraction. This ensures complete fuel utilization and maximum energy output

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The premixer acts as an intermediary device between the combustion liner and transition duct, preparing the fuel-air mixture for complete combustion in the second stage, thereby maximizing energy output from fuel particles

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If a premixer with multiple channels and fuel injectors is added, then fuel mixing and burning is more complete, but the device complexity increases

Engineering Contradiction:
Improvecombustion efficiencyVSAvoidpremixer structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The premixer incorporates multiple channels and fuel injectors that are segmented and positioned to create controlled swirl flow patterns. This segmentation of the mixing function across multiple elements achieves thorough fuel-air mixing and complete combustion while maintaining a manageable structural complexity through systematic arrangement

Inventive Principle:
Principle #1Segmentation

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

The axially staged combustion system achieves more complete fuel burning, minimizing NOx and CO emissions while increasing turndown capability, allowing the engine to operate efficiently at lower load settings and maximizing energy output.

Implementation Method 1

fuel and air pass through the channels positioned radially outward of the combustion liner, is imparted with a swirl, mix and is directed radially inward

Methodology Applied
Scientific EffectSwirl: Vortex Ring

Implementation Method 2

an axially staged combustion system achieves more complete fuel burning, minimizing NOx and CO emissions

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP3169938B1Axially staged gas turbine combustor with interstage premixer
Publication Date: 2019.09.04 ANSALDO ENERGIA IP UK LTD
  • EP3169938B1 patent drawingFigure 1
  • EP3169938B1 patent drawingFigure 2
  • EP3169938B1 patent drawingFigure 3

AI summary

The present invention discloses a novel and improved apparatus and method for reducing the emissions of a gas turbine combustion system. More specifically, a combustion system (200) is provided having a first combustion chamber (216) and a premixer (220) positioned proximate an outlet end of a combustion liner (208) for mixing a second fuel/air mixture with hot combustion gases and burning the subsequent mixture to achieve reduced emissions levels. The premixer is positioned generally about the combustion liner and includes a plurality of channels and fuel injectors for introducing a fuel/air mixture, induced with a swirl, into a second, axially staged combustor.