Nitrogen Purge Subsystem for Combustion Turbine Fuel Systems
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Solution Overview
Problem
Dual-fuel combustion turbines are susceptible to carbonaceous particulate formation in the liquid fuel system when out of service, leading to obstruction of fuel passages and reduced efficiency due to air infiltration and interaction with static liquid fuel, especially in warmer turbine compartments.
Innovation Solution
A nitrogen purge sub-system is implemented to remove air and residual fuel from the fuel system using a gravity drain and nitrogen flow, followed by venting to evacuate air and nitrogen during refilling, thereby mitigating carbonaceous particulate formation by ensuring the system is refilled with fuel and evacuated of air and nitrogen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the liquid fuel system is removed from service for extended periods, then the system can be maintained for rapid fuel transfer readiness, but carbonaceous particulate precipitation and deposition occur in the liquid fuel system due to air infiltration and heat
Solution Approach 1:
The system performs preliminary purging actions before extended outages by removing liquid fuel and introducing nitrogen to displace air. This preliminary action prevents carbonaceous particulate formation during the subsequent extended period when the system is out of service, while still maintaining readiness for rapid restart.
Solution Approach 2:
Nitrogen is introduced into the liquid fuel system to create an inert atmosphere that displaces air. This inert environment prevents oxygen from contacting the liquid fuel, thereby eliminating the conditions for carbonaceous particulate precipitation and deposition during extended outages.
2Ease of operation
If purge air is used to facilitate rapid fuel transfer readiness, then the liquid fuel system can be quickly restarted, but air infiltration into the liquid fuel system facilitates carbonaceous particulate formation
Solution Approach 1:
Nitrogen serves as an intermediary substance that performs the same functional role as purge air (displacing fuel and preparing the system for restart) but without the harmful side effect of promoting carbonaceous particulate formation. Nitrogen acts as a neutral mediator that prevents oxygen-fuel interaction.
3Reliability
If the liquid fuel system is kept out of service for extended periods, then maintenance and safety can be performed, but the system becomes susceptible to carbonaceous particulate precipitation and passage obstruction
Solution Approach 1:
Before taking the system out of service for maintenance, nitrogen purging is performed to remove air and create an inert atmosphere. This preliminary action ensures that during the extended maintenance period, no carbonaceous particulates can form, thus maintaining reliability while preventing passage obstruction.
Solution Approach 2:
The introduction of nitrogen creates a protective inert atmosphere that prevents oxygen from contacting the liquid fuel during extended outages. This inert environment maintains system reliability during maintenance periods while eliminating the chemical conditions necessary for carbonaceous particulate precipitation.
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 nitrogen purge sub-system effectively reduces the formation of carbonaceous particulates, maintaining fuel passage integrity and enhancing the reliability and efficiency of combustion turbines by preventing air-fuel interaction, thus extending the in-service life of fuel system components and reducing maintenance costs.
Implementation Method 1
removing fuel from at least a portion of the fuel system using a gravity drain process
Implementation Method 2
channeling nitrogen into at least a portion of the fuel system to facilitate removing air and residual fuel
Implementation Method 3
removing air and nitrogen from at least a portion of the fuel system during a fuel refilling process using a venting process
Data Source
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AI summary
A method of operating a fuel system (100) is provided. The method includes removing fuel from at least a portion of the fuel system using a gravity drain process The method also includes channeling nitrogen into at least a portion of the fuel system to facilitate removing air and residual fuel from at least a portion of the fuel system, thereby mitigating a formation of carbonaceous precipitate particulates. The method further includes removing air and nitrogen from at least a portion of the fuel system during a fuel refilling process using a venting process, such that at least a portion of the fuel system is substantially refilled with fuel and substantially evacuated of air and nitrogen. The method also includes removing air from at least a portion of the refilled fuel system using a venting process.