Method of and device for controlling fuel for gas turbine
AssigneeMitsubishi Heavy Industries, Ltd.
InventorSatoshi Tanaka
Life of this patent
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Abstract
Values such as a pressure for supplying fuel gas to a gas turbine, a pressure in a combustor casing of the gas turbine, an output of a generator connected to the gas turbine, and a controlled output for a flow rate control valve are detected by sensors. The detected values are input into a control device. A differential pressure across the flow rate control valve and a target value of the differential pressure are also input into the control device. The control device performs a desired arithmetic operation based on these input values to output a lift instruction for a pressure control valve.
Claims3
A gas turbine fuel control method of controlling a lift amount of a pressure control valve provided at a piping in which fuel for a gas turbine flows, by feeding back an actually obtained differential pressure across a flow rate control valve also provided at the piping to the pressure control valve and making the differential pressure follow a desired target value of the differential pressure, the gas turbine fuel control method comprising:
- expressing a conductance of the pressure control valve using
- a pressure used to supply fuel gas that is detected upstream of the pressure control valve at the piping,
- a pressure in a combustor casing of the gas turbine,
- an output of a generator connected to the gas turbine, and
- a controlled output for the flow rate control valve that is calculated based on a difference between an output target value of the generator and an actual output of the generator;
- obtaining an additional lift amount of the pressure control valve from a relationship between the conductance of the pressure control valve and lift;
- and
- adding the additional lift amount to the lift amount.
A gas turbine fuel control method of controlling a lift amount of a pressure control valve provided at a piping in which fuel for a gas turbine flows, by feeding back an actually obtained differential pressure across a flow rate control valve also provided at the piping to the pressure control valve and making the differential pressure follow a desired target value of the differential pressure, the gas turbine fuel control method comprising:
- obtaining a mass flow rate of inflow fuel to the gas turbine that is derived from a relationship with an output of a generator connected to the gas turbine;
- obtaining density of the fuel by multiplying a pressure for fuel gas supply detected upstream of the pressure control valve by a proportional constant for a relationship between the pressure of the fuel gas supply and the density of the fuel;
- obtaining the differential pressure across the flow rate control valve by multiplying a square of the mass flow rate by the density of the fuel to obtain a product, and dividing the product by a square of a conductance of the flow rate control valve which is obtained from a controlled output for the flow rate control valve using a function between the controlled output for the flow rate control valve and the conductance of the flow rate control valve, the controlled output being calculated based on a difference between an output target value of the generator and an actual output of the generator;
- obtaining a conductance of the pressure control valve by dividing a product between the mass flow rate and a square root of the fuel density, by a square root of a differential pressure across the pressure control valve, the square root of the differential pressure being expressed by subtracting a pressure in a combustor casing of the gas turbine from the pressure for the fuel gas supply to obtain a pressure and further subtracting the differential pressure from the obtained pressure;
- determining an additional lift amount of the pressure control valve using a function between the conductance of the pressure control valve and lift;
- and
- adding the additional lift amount to the lift amount.
Dependencies are inferred from the claim text.