Staged Liquid Fuel Combustion for Gas Turbine Liner Protection
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Solution Overview
Problem
Conventional gas turbine combustors face challenges when operating on liquid fuel, including insufficient penetration of liquid spray, liner wetting, coking, and thermal stress, which lead to unstable flames and increased emissions.
Innovation Solution
A liquid fuel cartridge system with radial fuel injection ports and a bundled tube fuel nozzle design, where air streams from the nozzle help atomize the liquid fuel, and downstream oxidant injection enhances the mixedness and velocity of combustion products, mimicking premixed flame characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If liquid fuel spray is extended across a large area, then fuel distribution is improved, but liner wetting and coking occur
Solution Approach 1:
The liquid fuel injection system is segmented into multiple injection zones along the axial direction. The first liquid fuel injection nozzle injects fuel at a first location, and the second liquid fuel injection nozzle injects fuel at a second location downstream, creating distributed fuel zones rather than a single large spray area. This segmentation allows fuel to be distributed across the combustion chamber while maintaining controlled spray patterns that prevent liner wetting.
Solution Approach 2:
The solution transitions from radial spray distribution to axial distribution by positioning fuel injection nozzles at different axial locations. The first nozzle is positioned upstream and the second nozzle downstream, creating a staged injection approach that distributes fuel along the axial dimension rather than relying solely on radial spray expansion, thereby avoiding liner contact.
2Use of energy by moving object
If combustion gas temperature is increased, then thermodynamic efficiency is improved, but NOx emissions increase
Solution Approach 1:
The combustion process is segmented into multiple stages with fuel injected at different axial locations. The first liquid fuel injection nozzle creates an initial combustion zone, and the second liquid fuel injection nozzle creates a downstream combustion zone. This staged combustion allows temperature control in different zones, maintaining high overall efficiency while limiting peak temperatures that generate NOx.
Solution Approach 2:
The system changes the spatial distribution parameter of fuel injection by using two nozzles at different axial positions rather than a single injection point. This parameter change enables staged combustion with controlled temperature profiles, achieving high thermodynamic efficiency through complete combustion while reducing NOx formation by avoiding excessive peak temperatures in any single zone.
3Stability of the object's composition
If liquid spray penetration is increased, then flame stability is improved, but liner wetting occurs
Solution Approach 1:
The fuel injection function is segmented between two nozzles positioned at different axial locations. Each nozzle provides moderate spray penetration sufficient for its local combustion zone, eliminating the need for any single nozzle to achieve excessive penetration that would cause liner wetting. The combined effect of both nozzles ensures stable combustion across the entire combustion chamber.
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 system achieves stable combustion, reduces liner wetting, and improves thermodynamic efficiency by producing combustion products with higher mixedness and velocity, thereby minimizing emissions and operational issues.
Implementation Method 1
The liquid fuel cartridge has a plurality of injection ports and is configured to produce combustion products via a diffusion flame
Implementation Method 2
air streams from the nozzle help atomize the liquid fuel
Implementation Method 3
downstream oxidant injection enhances the mixedness and velocity of combustion products
Data Source
AI summary
A combustion system includes a head end comprising a liquid fuel cartridge. The liquid fuel cartridge has liquid fuel injection ports and is configured to produce combustion products via a diffusion flame. A liner is configured to deliver the combustion products from the head end to an aft frame, and an injector having an outlet is located along the liner between the head end and the aft frame. The injector outlet delivers a stream of oxidant inwardly into the liner, such that a mixedness and a velocity of the combustion products are increased prior to the combustion products reaching the aft frame. A method of producing combustion products having characteristics of a premixed flame in a liquid fuel combustion system is also provided herein.