Heat Recovery Steam Generator Fuel Limiting Control
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Solution Overview
Problem
Conventional heat recovery steam generators with auxiliary burners face challenges in maintaining thermal balance and preventing equipment damage due to excessive fuel input, especially when the gas turbine output varies, leading to potential damage to heat-transfer pipes.
Innovation Solution
A heat recovery steam generator with multiple heat exchangers and a fuel limiting system that restricts fuel input to the auxiliary burner based on reference values, ensuring the charging quantity does not exceed defined limits, thereby preventing equipment damage and maintaining optimal steam generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the auxiliary burner is used to increase steam supply amount, then steam generation capability is improved, but exhaust gas temperature rises excessively causing damage to heat-transfer pipes
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the fuel input quantity to the auxiliary burner based on the gas turbine output. The control device modifies operational parameters (fuel input) according to varying conditions to maintain exhaust gas temperature within safe limits while maximizing steam generation capability.
2Productivity
If the auxiliary burner fuel input is increased to compensate for gas turbine output decrease, then steam generation is maintained, but heat-transfer pipes may be damaged due to excessive temperature
Solution Approach 1:
The patent implements feedback control where the control device continuously monitors gas turbine output and adjusts the auxiliary burner fuel input accordingly. This closed-loop feedback mechanism ensures that steam generation requirements are met while preventing excessive temperatures that would damage heat-transfer pipes, thus maintaining both productivity and reliability.
3Reliability
If multiple auxiliary burners are installed to prevent equipment deterioration, then equipment durability is improved, but device complexity increases
Solution Approach 1:
Instead of increasing the number of auxiliary burners, the patent achieves improved equipment durability through parameter changes - specifically by optimizing the fuel input quantity to existing burners based on gas turbine output. This approach maintains reliability while avoiding the complexity and cost associated with installing multiple burners.
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 system effectively regulates fuel input to the auxiliary burner, preventing overheating and ensuring safe operation by setting limits based on gas turbine output, reducing the risk of damage to heat-transfer pipes and optimizing steam generation.
Implementation Method 1
a heating unit configured to heat the exhaust gas by burning of fuel
Implementation Method 2
a plurality of heat exchangers consisting of a superheater, an evaporator and an economizer are installed in a duct along a flow direction of an exhaust gas from a gas turbine, so as to generate steam by utilizing the exhaust gas of the gas turbine
Data Source
AI summary
An auxiliary burner configured to heat exhaust gas on an upstream side of any one of heat exchangers, and a fuel supply system configured to supply fuel to the auxiliary burner. To avoid damage of a heat-transfer pipe by exhaust gas of high temperature, a reference value on which the restriction on the charging quantity to be supplied to the auxiliary burner is based is set, and the charging quantity of fuel to the auxiliary burner is restricted so as not to exceed a limit defined by the reference value.