Selective Deoxygenated Fuel System for Gas Turbine Coking Prevention
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Solution Overview
Problem
In gas turbine engines, stagnant fuel in fuel lines and injector nozzles can coking due to extreme temperatures, leading to decreased efficiency and damage, especially when oxygen content is high, as it lowers the coking temperature and increases coke production.
Innovation Solution
A multi-stage fuel injection system with a selective de-oxygenation unit that transitions to de-oxygenated fuel in the second fuel injector stage during non-use periods, using a controller and selective valve to manage fuel flow between standard and de-oxygenated fuel reservoirs, ensuring de-oxygenated fuel remains stagnant at higher temperatures without coking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If staged fuel injection is used to reduce emissions, then NOx and particulate matter emissions are reduced, but fuel stagnation occurs in unused fuel lines and injector nozzles leading to coking
Solution Approach 1:
The patent applies local quality by providing different fuel types to different fuel injection stages based on their operational status. Active stages receive standard fuel while inactive stages receive de-oxygenated fuel, allowing each stage to be protected according to its specific operational requirements and preventing coking in unused stages.
Solution Approach 2:
The patent changes the chemical composition parameter of the fuel by using de-oxygenated fuel (reduced oxygen content) for inactive fuel injection stages. This parameter change raises the coking temperature and prevents coke formation in stagnant fuel lines and injector nozzles during non-operational periods.
2Object-affected harmful factors
If de-oxygenated fuel is used in all stages continuously, then coking is prevented, but system complexity and fuel storage requirements increase
Solution Approach 1:
The patent segments the fuel injection system into active and inactive stages, applying different fuel types to each segment based on operational status. This segmentation allows coking prevention to be applied only where needed (inactive stages) rather than throughout the entire system, reducing overall complexity.
Solution Approach 2:
The patent applies partial action by providing de-oxygenated fuel only to inactive fuel injection stages rather than to all stages continuously. This partial application of the de-oxygenation measure prevents coking in the most vulnerable components while minimizing the overall system complexity and fuel storage requirements.
3Object-affected harmful factors
If de-oxygenation unit is installed onboard, then fuel coking is prevented, but weight and size of the system increase
Solution Approach 1:
The patent applies partial action by installing the de-oxygenation unit and using de-oxygenated fuel only for inactive fuel injection stages rather than for all stages continuously. This reduces the required de-oxygenation capacity and fuel storage volume, thereby minimizing the weight and size of the onboard system.
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
Prevents fuel coking in gas turbine engines by increasing the coking temperature of fuel, reducing maintenance costs and extending nozzle lifespan, while minimizing the size and weight of de-oxygenation systems by only using de-oxygenated fuel during specific operational phases.
Implementation Method 1
a fuel de-oxygenation unit having a fuel outlet fluidly coupled to the second fuel reservoir
Data Source
AI summary
A gas turbine engine includes a multi-stage fuel injection system including at least a first fuel injection stage and a second fuel injection stage, a first fuel reservoir fluidly connected to the first fuel injection stage and fluidly connected to a selective valve, and a second fuel reservoir fluidly connected to the selective valve. The selective valve connects one of the first fuel reservoir and the second fuel reservoir to the second fuel injection stage.