Abstract: In a steam system having a turbine driven by steam supplied from a high-pressure header to a low-pressure header, when the pressure in the low-pressure header drops, a turbine bypass valve is opened and the high-pressure side steam is supplied to the low-pressure side header in a normal control. When the turbine is tripped, steam is rapidly flow into the low-pressure side header and its pressure temporally increases. the steam in the low-pressure header is discharged through a discharge valve. After that, if a steam supply from the low-pressure header to another process increases, the discharge valve is closed. After the discharge valve is fully closed, an after-trip control is performed in which the opening of the turbine bypass valve is increased at an earlier timing than the normal control for preventing the steam amount in the low-pressure header to be too small. The control stability of the steam system when the turbine is tripped can be enhanced.

Abstract: A steam system control method applied to a steam system including: a low-pressure header storing low-pressure steam; a high-pressure header storing high-pressure header; a steam turbine connected between them; and a turbine bypass line introducing controlled amount of steam from the high-pressure header to the low-pressure header by bypassing the steam turbine. The low-pressure header has a blow-off valve for discharging excessive steam to the outside. The steam system control method includes: a normal time blow-off valve control step of PI controlling the opening of the blow-off valve; and a trip time blow-off control step of controlling the opening of the blow-off valve by changing the MV value to a predetermined trip time opening set value when the turbine is tripped.

Abstract: A steam system control method applied to a steam system including: a low-pressure header storing low-pressure steam; a high-pressure header storing high-pressure header; a steam turbine connected between them; and a turbine bypass line introducing controlled amount of steam from the high-pressure header to the low-pressure header by bypassing the steam turbine. The low-pressure header has a blow-off valve for discharging excessive steam to the outside. The steam system control method includes: a normal time blow-off valve control step of PI controlling the opening of the blow-off valve; and a trip time blow-off control step of controlling the opening of the blow-off valve by changing the MV value to a predetermined trip time opening set value when the turbine is tripped.

Abstract: In a steam system having a turbine driven by steam supplied from a high-pressure header to a low-pressure header, when the pressure in the low-pressure header drops, a turbine bypass valve is opened and the high-pressure side steam is supplied to the low-pressure side header in a normal control. When the turbine is tripped, steam is rapidly flow into the low-pressure side header and its pressure temporally increases. the steam in the low-pressure header is discharged through a discharge valve. After that, if a steam supply from the low-pressure header to another process increases, the discharge valve is closed. After the discharge valve is fully closed, an after-trip control is performed in which the opening of the turbine bypass valve is increased at an earlier timing than the normal control for preventing the steam amount in the low-pressure header to be too small. The control stability of the steam system when the turbine is tripped can be enhanced.

Abstract: The present invention includes an inflow quantity regulating means 5 for regulating the inflow quantity of a fuel gas to a compressor 1; a recycle valve 7 for returning the fuel gas discharged from the compressor 1 to the inlet side of the compressor 1; and a control means which sets a control operating value for operating the compressor 1 at a predetermined operation point, and controls the inflow quantity regulating means 5 and the recycle valve 7 based on the control operating value. The control means has a first control signal generating means 27 which generates a signal increasing with an increase in the operating value as a control signal for the inflow quantity regulating means 5 when the control operating value is a predetermined value or larger and a second control signal generating means 29 which generates a signal decreasing with an increase in the operating value as a control signal for the recycle valve 7 when the control operating value is smaller than the predetermined value.

Abstract: In the NH3 injection rate control method for an NOx removal apparatus, operating area of the apparatus is divided into first area in which molar ratio of NH3 injection rate with respect to NOx flow rate at an inlet of the apparatus is smaller than molar ratio at minimum point where NOx concentration assumes minimum value and second area in which the molar ratio is equal to or larger than the minimum point molar ratio, and virtual NOx concentration with respect to the molar ratio is set according to virtual characteristic line which varies monotonically to stride across desired operating point without rising with increase of the molar ratio from the first area to the second area. Moreover, feedback control is implemented for adjusting the NH3 injection rate with respect to the NOx flow rate in direction that the virtual NOx concentration is brought close to the desired NOx concentration.

Abstract: In the NH3 injection rate control method for an NOx removal apparatus, operating area of the apparatus is divided into first area in which molar ratio of NH3 injection rate with respect to NOx flow rate at an inlet of the apparatus is smaller than molar ratio at minimum point where NOx concentration assumes minimum value and second area in which the molar ratio is equal to or larger than the minimum point molar ratio, and virtual NOx concentration with respect to the molar ratio is set according to virtual characteristic line which varies monotonically to stride across desired operating point without rising with increase of the molar ratio from the first area to the second area. Moreover, feedback control is implemented for adjusting the NH3 injection rate with respect to the NOx flow rate in direction that the virtual NOx concentration is brought close to the desired NOx concentration.

Abstract: A transverse trolley 11 is transversally movable on a crane girder. A driver is provided for the transverse trolley 11. A pair of sheave blocks 14, 15 which is movable relative to a transverse trolley 11 are disposed on both (right and left) sides of a transverse trolley 11. Drivers are provided for the sheave blocks. Detectors 31 through 38 are provided which detect the displacement and velocity of the transverse trolley 11, the sway displacement and velocity of a hoisted load-piece 23 on both (right and left) sides and the displacement and velocity of the two sheave blocks 14, 15. A notch is disposed on an operation controlling panel of the transverse trolley 11 for setting a trolley transverse velocity by an operator. A transverse notch-driving control quantity detector 40 is provided which outputs signals indicative of notch-driving control quantity (a trolley transverse velocity set value) which is set by operating the notch.

Abstract: A transverse trolley 11 is transversally movable on a crane girder. A driver is provided for the transverse trolley 11. A pair of sheave blocks 14, 15 which is movable relative to a transverse trolley 11 are disposed on both (right and left) sides of a transverse trolley 11. Drivers are provided for the sheave blocks. Detectors 31 through 38 are provided which detect the displacement and velocity of the transverse trolley 11, the sway displacement and velocity of a hoisted load-piece 23 on both (right and left) sides and the displacement and velocity of the two sheave blocks 14, 15. A notch is disposed on an operation controlling panel of the transverse trolley 11 for setting a trolley transverse velocity by an operator. A transverse notch-driving control quantity detector 40 is provided which outputs signals indicative of notch-driving control quantity (a trolley transverse velocity set value) which is set by operating the notch.

Abstract: A transverse trolley (11) is transversally movable on a crane girder. A driver is provided for the transverse trolley (11). A pair of sheave blocks (14, 15) which is movable relative to a transverse trolley (11) are disposed on both (right and left) sides of a transverse trolley (11). Drivers are provided for the sheave blocks. Detectors (31 through 38) are provided which detect the displacement and velocity of the transverse trolley (11), the sway displacement and velocity of a hoisted load-piece (23) on both (right and left) sides and the displacement and velocity of the two sheave blocks (14, 15). A notch is disposed on an operation controlling panel of the transverse trolley (11) for setting a trolley transverse velocity by an operator. A transverse notch-driving control quantity detector (40) is provided which outputs signals indicative of notch-driving control quantity (a trolley transverse velocity set value) which is set by operating the notch.