Fuel Supply Acceleration Command for IGCC Load Response
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Solution Overview
Problem
In Integrated coal Gasification Combined Cycle (IGCC) plants, load changes lead to delays in output response of the steam turbine, causing rapid changes in gas turbine output and system gas pressure, which can result in instability and excessive responses to external disturbances due to existing control methods.
Innovation Solution
A control device calculates a fuel supply command value using a fuel supply acceleration command to adjust fuel amounts quickly in response to load changes, and incorporates a base fuel supply command value to account for slower output responses of the steam turbine, ensuring stable operation by balancing pressure and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the gas turbine output is rapidly adjusted to compensate for steam turbine delay, then the output response speed is improved, but the system gas pressure becomes unstable
Solution Approach 1:
The control device calculates a fuel supply acceleration command value in advance based on the expected load change amount, and adds this to the base fuel supply command value. This preliminary action allows the gasifier to prepare fuel gas supply changes before the pressure instability occurs, enabling faster response while maintaining pressure stability through coordinated control.
2Stability of the object's composition
If feedback control is used to settle pressure changes, then pressure stability is improved, but the response time increases
Solution Approach 1:
The control device performs preliminary calculation of the fuel supply acceleration command value based on the load change amount before the pressure deviation fully develops. This advance preparation reduces the time required for pressure stabilization by having the fuel supply already adjusted when the pressure change occurs, rather than waiting for feedback to detect and respond to the deviation.
Solution Approach 2:
The control device dynamically adjusts the fuel supply command value by combining the base fuel supply command value with the calculated acceleration command value that responds to load changes. This dynamic adjustment allows the system to adapt quickly to changing conditions while maintaining pressure stability, reducing the time needed for pressure settlement compared to static feedback control.
3Speed
If the gas turbine governor opening is adjusted rapidly, then the output change speed is improved, but excessive response to external disturbances occurs
Solution Approach 1:
The control device calculates the fuel supply acceleration command value in advance based on the load change amount, and combines it with the base fuel supply command value. This preliminary calculation ensures that fuel supply adjustments are made in a controlled manner that matches the actual load requirements, preventing excessive responses to external disturbances while maintaining fast output change capability.
Data Source
AI summary
A control device for a power generation system whereby power is generated by a first power source that operates by burning a fuel. The control device identifies, on the basis of a pressure difference in a prior-stage mechanism that supplies the fuel to the first power source, a fuel capacity that compensates for the pressure difference in the prior-stage mechanism. The pressure difference is the difference between a pressure set for the fuel before a load change in the prior-stage mechanism and a pressure set for the fuel after the load change in the prior-stage mechanism. The control device calculates a fuel supply command value, which is a command value for adjusting the amount of fuel supplied to a fuel supply device that supplies the fuel to the first power source, and is output to the fuel supply device using a fuel supply acceleration command value.