Fuel Gas Heater Temperature Control via Water Flow Feedback
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Solution Overview
Problem
The temperature of fuel gas on the outlet side of the fuel gas heater in a gas turbine combined cycle plant is not consistently controlled to a desired value due to insufficient adjustment of the water flow rate, leading to potential inefficiencies in power generation.
Innovation Solution
A control system that adjusts the flow rate of heated water supplied to the fuel gas heater based on the difference between the target temperature and the actual temperature of the fuel gas on the outlet side, using a combination of valve opening calculations and feedback control to regulate the water flow rate regulator valve and dump valve, ensuring precise temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the water flow rate to the fuel gas heater is controlled based on gas turbine load only, then the control system is simple, but the fuel temperature cannot be consistently maintained at the desired value
Solution Approach 1:
The patent implements feedback control by measuring the actual fuel temperature with a thermometer and comparing it to the target temperature, then adjusting the water flow rate regulator valve based on the temperature difference. This closed-loop feedback mechanism ensures the fuel temperature is consistently maintained at the desired value rather than relying solely on open-loop load-based control.
Solution Approach 2:
The control system dynamically adjusts the water flow rate based on real-time temperature measurements and varying operating conditions. The system transitions from static load-based control to dynamic temperature-based control, allowing the fuel temperature to be maintained at the desired value across different operating loads.
2Reliability
If the water flow rate is increased to ensure sufficient heating, then the fuel temperature can be maintained, but energy is wasted when the temperature is already sufficient
Solution Approach 1:
The feedback control mechanism continuously monitors the fuel temperature and adjusts the water flow rate accordingly. When the fuel temperature approaches or reaches the target value, the system automatically reduces the water flow rate, preventing unnecessary energy consumption while ensuring the temperature requirement is met.
Solution Approach 2:
The system changes the water flow rate parameter dynamically based on the actual temperature conditions. Instead of maintaining a constant high flow rate, the flow rate is adjusted as a variable parameter that responds to temperature measurements, optimizing the balance between reliable temperature maintenance and energy efficiency.
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 control system effectively maintains the fuel gas temperature at a desired value, enhancing the efficiency and reliability of the gas turbine combined cycle plant by accurately adjusting the water flow rate to match the temperature requirements.
Implementation Method 1
a fuel gas heater (FGH) is provided in a fuel system for the purpose of control of a temperature of a fuel which is supplied to a gas turbine. In the fuel gas heater, a fuel gas is heated by exchange of heat with heated water from a heat recovery steam generator (HRSG).
Data Source
AI summary
A control system is configured to control a temperature of a fuel which is supplied to a combustor of a gas turbine via a fuel gas heater, which is configured to heat the fuel of the gas turbine, by adjusting a flow rate of heated water which is supplied to the fuel gas heater. The control system includes a water flow rate adjusting unit configured to adjust the flow rate of the heated water which is supplied to the fuel gas heater based on a difference between a target temperature of the fuel and the temperature of the fuel on an outlet side of the fuel gas heater.