Fuel Additive Injection System for Gas Turbine Coke Prevention
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Solution Overview
Problem
Gas turbine engines experience coking in their liquid fuel supply systems due to increased temperatures near combustors, leading to hard deposits that clog fuel lines and valves, requiring costly hardware changes and downtime for flushing or additive mixing that may not be part of the control sequence.
Innovation Solution
A fuel additive injection system with a recirculation loop that mixes a chemical additive, such as an antioxidant, polymer inhibitor, or metal deactivator, with liquid fuel to inhibit coke formation, using a controller to manage the additive's supply and concentration, and an ejector for efficient mixing without moving parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If liquid fuel is stored in the fuel lines during gaseous fuel operation, then the liquid fuel supply system is ready for quick switching, but coke formation occurs due to increased temperature near combustors
Solution Approach 1:
The system performs preliminary flushing of the liquid fuel lines with an inert gas (nitrogen) before coke formation becomes problematic. This preventive action removes the liquid fuel that would otherwise decompose and form coke deposits during gaseous fuel operation, while maintaining the capability for quick switching back to liquid fuel mode.
2Object-affected harmful factors
If the fuel lines are flushed with liquid or gas to prevent coking, then coke formation is reduced, but hardware changes and downtime are required
Solution Approach 1:
The inert gas supply system serves multiple functions: it provides atmosphere control for the combustion chamber, and simultaneously flushes the liquid fuel lines to prevent coke formation. This multi-functionality eliminates the need for separate dedicated flushing hardware, reducing overall device complexity while effectively preventing coking.
3Object-affected harmful factors
If bulk fuel is mixed with additive to prevent coking, then coke formation is inhibited, but substantial retrofit costs and downtime are required
Solution Approach 1:
The invention extracts the additive mixing function from the bulk fuel treatment approach and implements it as a localized injection system at the fuel line entrance. This allows additive to be introduced only where needed (in the liquid fuel lines during gaseous operation) rather than treating all bulk fuel, significantly reducing retrofit requirements and costs while maintaining effective coke prevention.
4Object-affected harmful factors
If the fuel lines are flushed during operation, then coke formation is prevented, but fuel treatment may not be part of the control sequence and may leave fuel untreated in a trip
Solution Approach 1:
The system incorporates feedback through sensors that monitor fuel line conditions and automatically trigger the inert gas flushing sequence when liquid fuel is detected in the lines during gaseous fuel operation. This automated feedback control ensures consistent coke prevention without requiring manual intervention, and integrates seamlessly with the existing control sequence including trip scenarios.
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 effectively reduces coke formation, improving the reliability and efficiency of gas turbine engines by preventing clogging and extending maintenance intervals, while being compatible with existing systems and requiring minimal modifications.
Implementation Method 1
an ejector for efficient mixing without moving parts
Data Source
AI summary
A turbine engine comprising includes at least one combustor, a liquid fuel supply system, and a fuel additive injection system. The combustor is configured to combust liquid fuel. The liquid fuel supply system is configured to channel liquid fuel through at least one fuel line to the at least one combustor. The fuel additive injection system is coupled in fluid communication with the liquid fuel supply system. The fuel additive injection system includes a recirculation circuit configured to recirculate at least a portion of liquid fuel to the liquid fuel supply system. The fuel additive injection system is configured to channel chemical additive through the recirculation circuit for mixing with the at least a portion of liquid fuel to generate an additive fuel mixture configured to inhibit coke formation in the liquid fuel supply system.