Sequential Gas Turbine Combustor Start-Up for CO Emissions Control
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Solution Overview
Problem
Gas turbine assemblies face challenges in achieving quick and reliable start-up while maintaining emissions within regulatory limits, particularly during transient power variations and start-up phases, which are exacerbated by the use of renewable energy sources with unpredictable power production.
Innovation Solution
A method for operating a gas turbine assembly involving a sequential combustor system with two combustion stages, where the second combustor is ignited before reaching minimum load, allowing controlled CO emissions and rapid start-up, and a control system to manage fuel and air flow to optimize performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the gas turbine assembly operates with rapid start-up and load adjustments, then operational flexibility and responsiveness to grid demands improve, but CO emissions increase rapidly during start-up phases
Solution Approach 1:
The combustor assembly is divided into two separate combustors (first and second combustors) that can operate independently or together. During start-up, only the first combustor is activated, and during full operation, both combustors are active. This segmentation allows the system to meet emission limits during transient phases while maintaining operational flexibility.
2Productivity
If the gas turbine assembly increases power output quickly during transient situations, then responsiveness to grid demands improves, but emissions limits are violated
Solution Approach 1:
The second combustor is pre-configured and ready for ignition, allowing rapid transition from partial to full power operation. The control system is pre-programmed to manage the sequential activation of combustors based on grid demand signals, enabling quick response while maintaining emission compliance through controlled fuel injection and air flow management.
3Use of energy by moving object
If the gas turbine assembly operates at high temperatures to achieve high efficiency, then energy conversion efficiency improves, but NOx emissions increase
Solution Approach 1:
The combustion process is segmented into two stages with two separate combustors. This allows the system to distribute the thermal load and control combustion temperatures more effectively, reducing peak temperatures that lead to NOx formation while maintaining overall energy conversion efficiency through optimized fuel-air mixing in each combustor stage.
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
Enables quick and reliable start-up with controlled emissions, facilitating flexible operation and rapid load adjustments without violating emission limits, enhancing operational flexibility and responsiveness to grid demands.
Implementation Method 1
The compressor is configured for compressing incoming air supplied at its inlet
Implementation Method 2
The mixture of fuel and compressed air enters a combustion chamber where this mixture ignites
Implementation Method 3
The resulting hot gas flow leaves the combustion chamber and flows through the turbine assembly performing a rotating work on a rotor connected to a generator
Data Source
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AI summary
A method for operating a gas turbine assembly for a power plant comprises the steps of: - providing a gas turbine assembly (1) comprising a compressor (2), a combustor assembly (4), a turbine (5) and an generator; the compressor (2), the turbine (5) and the generator being connected to a common rotor (12) rotating around an axis (A); the combustor assembly (4) comprising at least one first combustor (14) and at least one second combustor (15) arranged downstream the first combustor (14) along a gas flow direction (D); - starting-up the gas turbine assembly (1); wherein the step of starting up the gas turbine assembly (1) comprising igniting the second combustor (15) before reaching the minimum load target value and after the ignition of the first combustor (14).