Combined Cycle Power Plant Startup Emission Control
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Solution Overview
Problem
Traditional start-up methods for combined cycle power plants require the gas turbine to operate in high emission areas for extended periods, leading to increased CO and NOx emissions due to the need to load the steam turbine slowly, which limits the efficiency and environmental compliance of the process.
Innovation Solution
A method that initializes the combined cycle power plant by operating the gas turbine within an emission-compliant window using only the first combustion chamber, then gradually introduces the sequential combustion chamber to achieve faster and more environmentally friendly start-up, minimizing time in high emission zones by optimizing the variable inlet guide vane positions and steam turbine loading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gas turbine is loaded up slowly through the high emission area to heat the steam turbine, then the steam turbine can be loaded up without preheating, but the gas turbine operates in high emission areas for extended periods
Solution Approach 1:
The start-up process is segmented into distinct phases: first loading the gas turbine to a first operating point within the emission compliant window, then regulating to a second operating point within the same window, and finally loading the steam turbine. This segmentation allows the gas turbine to remain in emission-compliant operation throughout the process.
Solution Approach 2:
The gas turbine is preliminarily loaded to operating points within the emission compliant window before steam turbine loading begins. This preliminary action establishes suitable operating conditions that enable subsequent steam turbine loading without requiring the gas turbine to operate in high emission areas.
2Loss of time
If the gas turbine is loaded up quickly through the high emission area, then start-up time is reduced, but emissions increase significantly
Solution Approach 1:
The method dynamically adjusts the gas turbine operating points during start-up, transitioning between different operating points within the emission compliant window. This dynamic adjustment allows for optimized start-up timing while maintaining emission compliance throughout the process.
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 approach significantly reduces emissions by limiting the gas turbine's operation in high emission areas to short periods, allowing for rapid and efficient start-up while maintaining compliance with environmental limits, thereby reducing the operational impact on emissions and extending the steam turbine's lifespan.
Implementation Method 1
a reheat boiler (Heat Recovery Steam Generator) fed with exhaust gas from the gas turbine
Implementation Method 2
a steam turbine fed with steam generated at the reheat boiler
Implementation Method 3
a gas turbine having a compressor, a first combustion chamber and a sequential combustion chamber
Data Source
Figure 1~3
Figure 4~5
Figure 6~9
AI summary
The method for starting up a combined cycle power plant (1), comprises operating the gas turbine (2) with only the first combustion chamber (4) and loading up the gas turbine (2) to a first operating point (45) within the second emission compliant operating window (40), then within the second emission compliant operating window (40), regulating the gas turbine (2) up to a second operating point (47) and loading up the steam turbine (11), then operating the gas turbine (2) with both the first combustion chamber (4) and the sequential combustion chamber (5) and further regulating the gas turbine (2) to a third operating point (48) within the first emission compliant operating window (21).