Gas Turbine Recirculation Control for Flashback Prevention
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Solution Overview
Problem
Power plants face challenges in operating gas turbine units when switching to fuels with higher C2+ and/or H2 content, as it can lead to flashback and reduced efficiency, requiring lower combustion temperatures which decrease power and performance.
Innovation Solution
A control unit is implemented to regulate the mass flow rate of the recirculated flow in a gas turbine unit based on the C2+ and/or H2 content of the fuel, using sensors and look-up tables to maintain optimal combustion conditions without reducing the combustion chamber temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the recirculated flow mass flow rate is increased to reduce discharged flow and increase CO2 concentration, then the plant and operating costs are reduced, but the oxygen content in the combustion chamber decreases and combustion is impaired
Solution Approach 1:
The patent applies dynamics by making the recirculated flow mass flow rate adjustable and controllable through a diverter valve, allowing the system to adapt to different fuel compositions. The control unit dynamically modifies the recirculated flow based on detected fuel properties, transforming a static system into a dynamic one that can optimize both cost and combustion quality under varying conditions.
Solution Approach 2:
The patent changes the parameter of recirculated flow mass flow rate based on fuel composition detection. When high reactivity fuel is detected, the control unit adjusts the recirculated flow to prevent flashback while maintaining efficient combustion. This parameter adjustment resolves the contradiction by adapting the system to different fuel types, allowing cost optimization with standard fuel and safety maintenance with high reactivity fuel.
2Reliability
If the combustion chamber temperature is reduced to prevent flashback with high reactivity fuel, then flashback is avoided, but power and efficiency are reduced
Solution Approach 1:
The patent applies preliminary action by detecting the fuel composition (C2+ and H2 content) before combustion occurs. The control unit proactively adjusts the recirculated flow mass flow rate based on the detected fuel properties, preventing flashback before it can occur. This eliminates the need for conservative temperature reduction, allowing the combustion chamber to operate at optimal temperatures for power and efficiency while maintaining safety.
Solution Approach 2:
The patent implements feedback through a detection device that continuously monitors fuel composition and provides information to the control unit. The control unit uses this feedback to dynamically adjust the recirculated flow, creating a closed-loop control system. This feedback mechanism allows the system to respond to actual fuel conditions rather than operating with fixed conservative settings, thereby maintaining both safety and performance.
3Reliability
If the recirculated flow is increased to dilute high reactivity fuel, then flashback is prevented, but the flow to be treated increases significantly
Solution Approach 1:
The patent changes the recirculated flow parameter dynamically based on the detected fuel composition. Rather than using fixed high dilution ratios for all high reactivity fuels, the control unit adjusts the recirculated flow to the minimum necessary to prevent flashback for each specific fuel type. This optimized parameter adjustment reduces the excessive flow treatment while maintaining safety.
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
This solution allows for safe and efficient operation of gas turbine units with fuels of varying reactivity, preventing flashback and maintaining power and efficiency by dynamically adjusting the recirculated flow in response to changing fuel compositions.
Implementation Method 1
a fuel is burnt together with the mixture in at least one combustion chamber of the gas turbine unit
Implementation Method 2
The recirculated flow is fed into a mixer together with fresh air to form a mixture that is fed to the gas turbine unit
Implementation Method 3
within the boiler 9 the flue gases 8 transfer heat to water of the steam unit 10
Data Source
AI summary
The power plant includes a gas turbine unit adapted to feed flue gases into a diverter where they are divided into a recirculated flow and a discharged flow. The recirculated flow is fed into a mixer together with fresh air to form a mixture that is fed to the gas turbine unit. The gas turbine unit includes a combustion chamber where a fuel is burnt together with the mixture. A control unit is provided, that is supplied with information regarding the fuel C2+ and/or H2 content and is connected to at least the diverter to drive it and online regulate the recirculated flow mass flow rate in relation to the fuel C2+ and/or H2 content.