JP4287940B2 - Pressurized fluidized bed boiler apparatus and control method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pressurized fluidized bed boiler apparatus and a control method thereof, and in particular, prevents surging of a gas turbine compressor of a pressurized fluidized bed boiler apparatus having a pressure vessel containing a boiler connected to a gas turbine. The present invention relates to a pressurized fluidized bed boiler apparatus and a control method thereof that can control the amount of fuel or air necessary for boiler combustion.
[0002]
[Prior art]
FIG. 7 is an explanatory diagram showing an apparatus system of a pressurized fluidized bed plant to which the present invention is applied. In the figure, this apparatus includes a boiler pressure vessel 74 that houses a boiler body 75, a gas turbine compressor 71 that supplies air to the boiler pressure vessel 74 via an air duct 82, and a high-pressure exhaust gas duct 76 to the boiler body 75. And a gas turbine main body 79 provided coaxially with the gas turbine compressor 71, an exhaust duct 80 at the outlet of the gas turbine main body 79, and a gas turbine connecting the exhaust duct 80 and the air duct 82. The air duct 82, the high-pressure exhaust gas duct 76, and the gas turbine bypass duct 83 are provided with a compressor outlet valve 73, a gas turbine inlet valve 77, and a gas turbine bypass valve 78, respectively. Yes. 72 is an air flow rate adjusting mechanism of the compressor 71, and 81 is a chimney.
[0003]
In such a configuration, the fuel supplied from the fuel supply nozzle (not shown) to the boiler body 75 is pressurized by the gas turbine compressor 71 and supplied to the boiler body 75 via the air duct 82 and the boiler pressure vessel 74. The high-pressure exhaust gas generated by mixing with the gas is guided to the gas turbine main body 79 through the high-pressure exhaust gas duct 76, and the gas turbine main body 79 is started.
[0004]
FIG. 8 is a diagram showing static characteristics of a general pressurized fluidized bed plant. In FIG. 8, the compressor passing air flow rate controlled by the air flow rate adjusting mechanism in accordance with the plant load increases substantially in proportion to the increase in the plant load. On the other hand, it can be seen that the gas turbine inlet gas temperature rises steeply as the plant load increases. By the way, since the air flow rate adjusting mechanism is installed on the inlet side in order to improve the efficiency of the compressor, the net compressor inlet pressure becomes a negative pressure, and the ratio of the negative pressure increases as the passing air amount decreases. The ratio between the compressor outlet pressure and the inlet pressure is called the pressure ratio, and the limit value, that is, the upper limit value that does not cause the compressor to surging is set by the gas turbine employed. When surging occurs, not only the necessary air does not flow and the plant cannot be operated, but also the compressor itself may melt due to a rise in temperature.
[0005]
Conventionally, in such a pressurized fluidized bed boiler apparatus, when the load changes, the air flow adjustment mechanism of the compressor is operated directly so that the required air amount according to the required heat input (fuel input amount) is obtained. A method of controlling the amount was taken.
However, in such a conventional control method, in order to compensate for the delay in the boiler inflow air due to the volumetric action of the pressure vessel, which is a characteristic of the pressurized fluidized bed boiler device, the flow rate of air passing through the compressor is increased to an appropriate value or more when the load increases. It was necessary to increase it and reduce it below the appropriate value when the load dropped. Reducing the air flow rate leads to a decrease in the compressor inlet pressure, and the compressor pressure ratio is increased to cause surging, resulting in a problem that the load changing speed at the time of load drop is reduced. In addition, when the load drops, the gas turbine inlet gas temperature generally remains high according to the heat capacity of the high-pressure gas duct, and when the gas turbine inlet gas temperature is high, the gas pressure in the boiler also remains high. There has been a problem that the pressure ratio becomes high and compressor surging is likely to occur.
[0006]
To avoid such compressor surging, if the compressor pressure ratio may exceed the surging limit during load drop, it will be fully closed during normal operation to protect the compressor by a protective interlock. Control is performed to open the gas turbine bypass valve and reduce the pressure ratio.
However, when the gas turbine bypass valve is opened, since the amount of air passing through the compressor is constant, there is a problem that the boiler inflow air amount is insufficient and it is difficult to continue the operation of the boiler.
[0007]
That is, in the above prior art, the rate of change in load drop of a pressurized fluidized bed plant is effectively controlled by the surging limit value of the compressor, the heat capacity of the high-pressure exhaust gas duct, the volume of the pressure vessel, etc. It was not equipped with load change characteristics according to demand.
In order to solve such problems, in recent years, when the boiler load drops, the pressure in the pressure vessel containing the boiler is set to zero when the control deviation between the set pressure corresponding to the load command and the actual detected pressure is zero. Thus, a method of controlling by a gas turbine bypass valve has been proposed (Japanese Patent Laid-Open No. Hei 6-272815), but this method can prevent surging of the gas turbine compressor at the time of high speed load drop. When the flow rate fluctuates due to factors other than the load command, the amount of fuel actually burned in the boiler at the time of load drop does not necessarily correspond to the amount of input air, and the air / fuel ratio changes, which increases the oxygen concentration However, there is a problem in controlling the exhaust gas characteristics that the amount of generated NOx increases while the generated CO increases when the oxygen concentration is too low.
[0008]
By the way, the compressor used in the pressurized fluidized bed boiler plant is designed with a high compression ratio as compared with the conventional blower, and the operation restriction is determined by the pressure ratio as described above, and the pressure ratio on the restriction is determined. Surging occurs when the value exceeds. Therefore, it is necessary to open the gas turbine bypass system valve at a pressure ratio before surging occurs so that the pressure difference is eliminated.
[0009]
However, when the plant differential pressure increases while the plant load is static, if the gas turbine bypass valve is opened to avoid compressor surging, the boiler inflow combustion air flow rate will decrease and the amount of air will be insufficient. There is a problem of doing. That is, the compressor air flow rate adjusting mechanism is controlled to be proportional to the amount of fuel supplied to the boiler, and the signal is corrected by the oxygen concentration in the exhaust gas as a result of combustion. Therefore, when the gas turbine bypass valve is opened, an air amount increase signal is output only when the oxygen concentration is reduced as a result of combustion. Therefore, the operation of the exhaust gas oxygen concentration correction circuit becomes very slow due to the stability of the control, and is primarily However, there is a problem that the amount of air flowing into the boiler is insufficient and the SOx concentration and the unburned content in the exhaust gas increase.
[0010]
In a pressurized fluidized bed plant, the gas turbine is composed of a single unit. Therefore, when a compressor trip occurs, fuel injection is immediately shut off and the plant is stopped, as in a conventional conventional boiler having only one blower. There must be.
[0011]
[Problems to be solved by the invention]
The present inventionSectionThe title is to solve the above-mentioned problems of the prior art, use the conventional equipment as it is, and keep the oxygen concentration in the exhaust gas constant or according to the characteristics determined in static characteristics even during load changes according to power demand. Can driveAnd it is providing the control method of a pressurized fluidized bed boiler apparatus which can ensure the stable continuous operation | movement of a plant, even if surging of a gas turbine compressor generate | occur | produces.
[0013]
[Means for Solving the Problems]
In order to solve the above problems, the invention claimed in the present application is as follows.
(1) A pressure vessel that houses a boiler body, a gas turbine compressor that supplies pressurized air to the pressure vessel via an air duct, and a high-pressure exhaust gas that is discharged from the boiler body and supplied via a high-pressure exhaust duct A pressurized fluidized bed boiler apparatus comprising: a gas turbine that is operated by a gas turbine; an exhaust duct that discharges the exhaust gas from the gas turbine; and a gas turbine bypass duct that includes an on-off valve that connects the exhaust duct and the air duct. In the control method, when the load of the boiler device drops, first, the amount of pressurized air passing through the gas turbine compressor is controlled within a range equal to or greater than the surging limit value of the compressor, and then the gas turbine bypass duct is supplied to the gas turbine bypass duct. When opening the on-off valve provided to bypass a part of the pressurized air to the gas turbine outlet, The pressurized air amount supplied to the boiler body by adjusting the opening degree of the on-off valve, controlled required amount according to the amount of fuel injected into the boiler bodyWhen the pressure ratio of the gas turbine compressor rises to a predetermined value or more, the gas turbine bypass duct on-off valve is opened to protect the compressor from surging, and a part of the pressurized air is discharged from the gas turbine outlet. The amount of fuel supplied to the boiler body is reduced to an amount corresponding to the amount of air that passes through the gas turbine bypass duct and bypasses to the gas turbine outlet. A control method for a pressurized fluidized bed boiler apparatus, wherein the control is performed so as to correspond.
[0015]
(2) The fluidized bed height is lowered by adjusting the amount of pressurized air supplied to the boiler body or the flow velocity in accordance with the throttle amount of the fuel.1) Is a method for controlling a pressurized fluidized bed boiler apparatus.
[0016]
(3)the above(1), When the pressure ratio of the gas turbine compressor rises to a predetermined value or more, the on-off valve of the gas turbine bypass duct is opened as a protective operation against surging of the compressor. A portion of the compressed air that is bypassed to the gas turbine outlet, and the amount of pressurized air that passes through the gas turbine compressor is equivalent to the amount of air that passes through the gas turbine bypass duct and is bypassed to the gas turbine outlet. And a control method for the pressurized fluidized bed boiler apparatus, wherein the control is performed so that the amount of air supplied to the boiler body corresponds to the amount of fuel.
[0017]
(4)the above(1), When the pressure ratio of the gas turbine compressor rises to a predetermined value or more, the on-off valve of the gas turbine bypass duct is opened as a protective operation against surging of the compressor. When a part of the pressurized air is bypassed to the gas turbine outlet and the boiler load is high and the compressor passing air flow rate is close to the upper limit value, the fuel supply amount to the boiler body passes through the gas turbine bypass duct. Then, the amount of air to be bypassed to the gas turbine outlet is throttled, and when the boiler load is low and the amount of fuel input to the boiler body is in the vicinity of the lower limit, the passing pressurized air amount of the gas turbine compressor is This is equivalent to the amount of air that passes through the gas turbine bypass duct and bypasses to the gas turbine outlet. Is increased, the fuel amount and the method of controlling a pressurized fluid Doso boiler system air amount and controls to correspond supplied to the boiler body.
[0018]
(5)the above(1), When the pressure ratio of the gas turbine compressor rises to a predetermined value or more, the on-off valve of the gas turbine bypass duct is opened as a protective operation against surging of the compressor. And a compressor for bypassing a part of the pressurized air to the gas turbine outlet and reducing the amount of fuel supplied to the boiler body according to the amount of air passing through the gas turbine bypass duct and bypassing to the gas turbine outlet A control method for a pressurized fluidized bed boiler apparatus, wherein an operation for increasing a passing pressurized air amount is performed at the same time so that a fuel amount and an air amount supplied to the boiler body correspond to each other.
[0021]
Main departureIn order to avoid surging of the gas turbine compressor, when the gas turbine bypass valve is opened and air is bypassed to the gas turbine outlet, the operation of correcting the ratio of the fuel input to the boiler and the air supply amount to the optimum value is performed. This is performed rapidly before the correction operation based on the exhaust gas oxygen concentration takes place. The correction amount can be easily obtained if the compressor outlet pressure and the gas turbine bypass valve passage air flow rate are known.
[0022]
Using FIG.The present inventionexplain. Drawing 1 is a figure showing the plant characteristic at the time of boiler load fall of a fluidized bed boiler device. In the figure, it can be seen that the gas turbine inlet pressure (boiler furnace pressure) drops higher than the static characteristics. When the plant load drops from 1 to 2, if the flow rate of air passing through the compressor is reduced on a static characteristic basis, the pressure ratio becomes higher and surging may occur. Therefore, in the present invention, the compressor inlet pressure is set to be less than the surging limit value. Reduce to a high range, thereby flowing the flow rate of air passing through the compressor more than the appropriate value. In this state, open the gas turbine bypass valve to bypass part of the pressurized air to the gas turbine outlet and supply it to the boiler body. The air flow rate to be controlled is controlled to a required amount corresponding to the fuel flow rate at the time of load drop. Even if the gas turbine bypass valve is opened and the compressor outlet pressure decreases, the compressor passage air amount does not change as a characteristic of the compressor.
[0023]
furtherIn this case, if the compressor passing air flow rate is swallowed by the gas turbine as it is, the amount of combustion air and the amount of gas increase, resulting in an increase in the gas turbine inlet pressure, and an increase in exhaust gas oxygen concentration due to an excessive amount of combustion air. In the present invention, the gas turbine bypass valve is opened and a part of the pressurized air is bypassed to the gas turbine outlet, whereby the flow rate of air supplied to the boiler body is reduced when the load drops. By controlling in accordance with the amount of fuel, an increase in exhaust NOx can be suppressed.
[0024]
FIG. 4 shows the present invention.NoharaFIG. 3 is a diagram illustrating the relationship between the compressor passing air flow rate, the operating pressure, and the compressor surging detection pressure. In the figure, when the plant is new and the gas turbine is less contaminated, the fluidized bed boiler unit is operated under conditions close to the planned operating point 1, but the pressure gradually increases due to clogging of the boiler piping system, etc., and compressor surging is detected. When increased to pressure 2, the gas turbine bypass valve is opened to protect the compressor and the pressure balance moves to point 3. At this point 3, the compressor passing air flow rate does not change, but the boiler inflow air amount is reduced by an amount corresponding to the amount of air bypassed to the gas turbine outlet by opening the gas turbine bypass valve.
[0025]
In order to cope with such a decrease in the required air amount, in the present invention, the pressure in the boiler rises to the compressor surging detection pressure (2), the gas turbine bypass valve is opened to protect the compressor, and the gas turbine compressor passes through. At point (3) where a part of the air volume is bypassed to the gas turbine outlet, the fuel supply amount is reduced to the boiler load corresponding to point (4) (Solution A) or until it corresponds to point (5). The flow rate of air passing through the compressor is increased (Countermeasure B) so that the amount of air flowing into the boiler corresponds to the amount of fuel, thereby ensuring stable combustion of the boiler while avoiding surging of the gas turbine compressor.
[0026]
In the present invention, it is preferable to apply the coping method A when the load is high and the coping method B when the load is low.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in detail by way of examples.
FIG. 2 is a basic control circuit diagram showing an air amount control method at the time of load drop of the pressurized fluidized bed boiler apparatus which is an embodiment of the present invention (switched to another circuit at the time of load rise).
[0028]
In the figure, in the static state, a required fuel input signal is generated by the fuel request function generator 2 based on the boiler load request signal 1, and the boiler main body is supplied to the boiler body by the fuel input operating device 3 based on the required fuel input signal. The supplied fuel flow rate is controlled. On the other hand, the air flow rate supplied to the boiler body is controlled to an optimum flow rate corresponding to the fuel supply amount by the air flow rate adjusting mechanism 6 of the compressor.
[0029]
Now, when the fuel input amount is reduced due to the load drop of the boiler, the necessary air amount input signal for reducing the supply air flow rate generated by the air ratio setting device 4 based on the boiler load request signal 1 is transmitted. Since this signal is sent to the air flow rate adjusting mechanism 6 of the compressor through the delay characteristic function generator 5, the throttle control of the air flow rate is carried out programmatically. Therefore, at the beginning of the load drop, the amount of air passing through the compressor is equal to or greater than the appropriate amount corresponding to the fuel input amount reduced by the load drop. At this time, the required combustion air amount signal 8 of the boiler corresponding to the fuel input amount is sent to the comparator 9, where it is compared with the actual detection value of the boiler inflow air flow meter 7 and corrected by the controller 10. After that, the fuel is sent to the gas turbine bypass valve 11 and adjusted so as to increase the amount of air that is bypassed through the bypass valve, whereby the amount of air flowing into the boiler body is reduced as the load drops. It is controlled to the required amount corresponding to the supply amount.
[0030]
According to this embodiment, when the boiler load drops, the operation of restricting the air flow rate passing through the compressor by the compressor air flow rate adjustment mechanism is controlled programmatically to delay the predetermined time, and a boiler corresponding to the fuel input amount accompanying the load drop is necessary. By bypassing a part of the compressor passing air amount to the gas turbine outlet by the gas turbine bypass valve based on the combustion air amount signal, and adjusting the air supply amount to the boiler body to become the required amount, The air supply amount to the boiler can be controlled to a necessary amount corresponding to the boiler load without reducing the flow rate unnecessarily. Therefore, it is possible to secure the air flow rate corresponding to the load drop of the boiler and increase the load drop rate while avoiding surging due to an increase in the pressure ratio of the compressor.
[0031]
FIG. 3 is a basic control circuit diagram showing another embodiment of the present invention.
This control method is different from the above embodiment in that excess air flows through the compressor in advance, and in this state, the required air flow rate of the boiler is directly controlled by the air flow regulator of the compressor. That is, when the fuel input amount is reduced due to the boiler load drop, the opening degree of the gas turbine bypass valve 11 is controlled programmatically through the opening degree request signal generator 13 in accordance with the load change rate signal 12 to In this state, a part is bypassed to the exhaust duct at the gas turbine outlet, and an amount of air larger than the amount corresponding to the amount of fuel after the load drop is supplied to the boiler body flows. Thus, the air flow rate adjusting mechanism 6 of the compressor is controlled so that the flow rate of air flowing into the boiler body becomes a necessary amount corresponding to the amount of injected fuel after the load drop.
[0032]
According to this embodiment, as in the above embodiment, the air flow rate flowing into the boiler body is limited to the required amount corresponding to the fuel amount reduced by the drop in the boiler load without unnecessarily reducing the air flow rate through the compressor. Therefore, it is possible to increase the load drop rate by securing the air flow rate corresponding to the load drop of the boiler while avoiding surging due to the increase in the pressure ratio of the compressor.
[0033]
In this embodiment, the on-off valve provided in the gas turbine bypass duct may be used only for original compressor surging protection, and the bypass air flow rate may be controlled by a newly provided valve.
FIG. 5 is an explanatory diagram showing a control circuit according to another embodiment of the present invention. In this figure, this method generates a fuel request function based on the boiler load request signal 21 when the gas turbine bypass valve is opened to reduce the supply of air to the boiler body in order to avoid surging of the gas turbine compressor. The subtractor 24 subtracts the fuel reduction command signal 23 based on the surge generation signal from the required fuel input amount signal obtained by the generator 22, and the amount of fuel input to the boiler body based on the subtracted signal is reduced. It is controlled by the fuel input operation unit 25 so as to be a required amount corresponding to the air supply amount.
[0034]
According to this embodiment, the flow rate of air supplied to the boiler body is reduced by opening the gas turbine bypass valve and bypassing part of the compressor passing air amount to the gas turbine outlet in order to avoid surging of the gas turbine compressor. The subtractor 24 subtracts the fuel reduction command signal 23 based on the surge generation signal from the required fuel input amount signal obtained by the fuel demand function generator 22 based on the boiler load demand signal 21. Based on the signal, the amount of fuel input to the boiler is controlled so as to be the required amount corresponding to the reduced air supply amount. In addition, surging of the compressor can be avoided.
[0035]
In the present embodiment, it is preferable to reduce the fuel input amount to the boiler body so as to correspond to the air supply amount and at the same time lower the bed height corresponding to the load change. Thereby, the change of the layer temperature can be eliminated. As a method of lowering the bed height, for example, a method of adjusting the amount or flow rate of pressurized air supplied to the boiler body can be mentioned.
In the present invention, when the gas turbine bypass valve is opened to avoid surging of the gas turbine compressor and the flow rate of air supplied to the boiler body is reduced, the fuel demand function generator is generated based on the boiler load demand signal 21. 22, the air flow rate addition command signal 27 based on the surge generation signal calculated by the calculator 32 based on the surge generation signal 33 and the plant load signal 34 is added by the adder 26 to the required air input amount signal obtained in 22, The air flow rate signal 28 is corrected through the comparator 29 and the controller 30 based on the added signal, and the gas turbine bypass valve is opened by controlling the air flow rate adjusting mechanism 31 based on the corrected signal. As a result, the flow rate of air passing through the compressor is increased by an amount corresponding to the amount of air bypassed to the gas turbine outlet. The air flow supplied to the can also be controlled to correspond to the insertion amount of fuel into the boiler body.
[0036]
In the present invention, when the pressure ratio of the gas turbine compressor is increased to a predetermined value or more, the gas turbine bypass valve is opened to avoid surging of the compressor, and the flow rate of air supplied to the boiler body is reduced. When the boiler load is high and the flow rate of air passing through the compressor is close to the upper limit, the amount of fuel supplied to the boiler is equivalent to the amount of air that passes through the gas turbine bypass valve and is bypassed to the gas turbine outlet. When the boiler load is low and the fuel input amount is close to the minimum load, the gas turbine bypass valve is controlled by the air flow adjustment mechanism of the compressor. The air passing through the compressor is increased by an amount corresponding to the amount of air that passes through the gas turbine and is bypassed to the gas turbine outlet. It is preferable to control the amount. As a result, stable driving performance can be further improved.
[0037]
In the present invention, when the gas turbine bypass valve is opened to reduce the surging of the gas turbine compressor and the amount of air supplied to the boiler body is reduced, the operation of reducing the amount of fuel input to the boiler body and the passage of the compressor The operation of increasing the air amount can be performed at the same time, whereby the fuel amount supplied to the boiler body can be made to correspond to the air amount. As a result, the mutual operation amount is reduced and the control responsiveness is improved.
[0038]
In the present invention, when the gas turbine is started, in order to prevent the leak gas from flowing backward from the gas turbine inlet to the boiler body side, pressurized air is supplied to the boiler body in advance through the air duct, and the boiler body is supplied to the gas turbine. It is preferable to form a pressurized air flow that flows toward the air flow, entrain the leak gas in the air flow, bypass the gas turbine, and discharge it to the gas turbine outlet exhaust duct.
[0039]
FIG. 6 illustrates the present invention.Reference exampleIt is explanatory drawing of the fluidized-bed boiler apparatus which shows. This apparatus includes a pressure vessel 50 containing a boiler furnace 54, a gas turbine compressor (air compressor) 42 for supplying air to the pressure vessel 50 through an air duct 61, and the boiler furnace 54. A gas turbine 47 that is operated by high-pressure exhaust gas supplied through a high-pressure exhaust gas duct 60 having 55 and 56, an exhaust duct 62 that exhausts exhaust gas at the outlet of the gas turbine 47, the exhaust duct 62, and the air duct 61. In a pressurized fluidized bed boiler apparatus having a gas turbine bypass duct 67 having an on-off valve 66 connected thereto, a booster fan 49 for supplying pressurized air to the air duct 61 via a branch pipe 64 is provided, and the gas A gas turbine that connects the high-pressure exhaust gas duct 60 at the turbine inlet and the exhaust duct 62 at the gas turbine outlet. The provided Nbaipasu pipe 57, is provided with a bypass valve 58 valve and vacuum orifices 59 in the bypass pipe 57. 41 is a compressor inlet pressure reducing valve, 43 is a compressed air outlet valve, 44 is a compressed air bypass valve, 45 is a combustor, 46 is a high pressure gas stop valve, 48 is an exhaust silencer, 51 is hot air generated A furnace, 52 is an air box, and 53 is a fluidized bed.
[0040]
In such a configuration, prior to starting the gas turbine 47, the on-off valve 66, the compressor outlet valve 43, and the high-pressure gas stop valve 46 are closed, and the booster fan 49 is started to reduce the pressure in the pressure vessel 50 to 1 to 2 kg / cm²The pressure is increased to g and air is supplied to the high-pressure exhaust gas duct 60, the bypass valve 48 of the gas turbine bypass pipe 57 is opened, the pressure is reduced by the pressure-reducing orifice 59, and exhausted to the exhaust duct 62 upstream of the exhaust silencer 48. In this state, the compressed air bypass valve 44 is opened, the air compressor 42 and the gas turbine 47 are activated by a gas turbine activation motor (not shown), and the rotational speed is increased to, for example, 20 to 30 rotations. Air is supplied from 42 to the gas turbine 47 via the compressed air bypass valve 44 and the combustor 45. Next, the combustor 45 is ignited to increase the rotational speed of the gas turbine 47 to a rated value of 100%. At this time, the leak gas leaking from the high temperature gas stop valve 46 and going to flow back to the boiler side is reduced in temperature along with the air flow exhausted to the exhaust duct 62 through the high pressure exhaust gas duct 60 and the gas turbine bypass pipe 57. After the pressure is reduced, the exhaust gas is exhausted to the exhaust gas duct 62.
[0041]
BookReference exampleAccording to the present invention, the booster fan 49 is connected to the air supply duct 61 via the branch pipe 64, and the gas turbine bypass pipe 57 that connects the high-pressure exhaust gas duct 60 and the exhaust duct 62 is provided. The leak gas leaking from the gas stop valve 46 is boosted by the booster fan 49 and discharged to the exhaust duct 62 at the outlet of the gas turbine 47 along with the air flow flowing through the pressure vessel 50, the furnace 54, and the high-pressure exhaust gas duct 60. Therefore, it is possible to prevent the leak gas when starting the gas turbine from flowing backward to the boiler furnace side. Therefore, clogging of the fluidizing medium into the fluidizing air nozzle can be prevented in advance.
[0042]
The above-described leak gas backflow prevention method and apparatus configuration can be applied to a general one as long as it is a pressurized fluidized bed boiler apparatus.
[0043]
【The invention's effect】
According to the invention described in claim 1 of the present application, when the load of the boiler device drops, first, the amount of pressurized air passing through the gas turbine compressor is controlled in a range equal to or greater than the surging limit value of the compressor, according to the load change rate, Next, the open / close valve provided in the gas turbine bypass duct is opened to bypass a part of the pressurized air to the gas turbine outlet, and the pressurized air supplied to the boiler body by adjusting the opening of the open / close valve The amount is controlled to the required amount according to the amount of fuel charged into the boiler bodyFurther, when the pressure ratio of the gas turbine compressor rises above a predetermined value, the gas turbine bypass duct on-off valve is opened to protect the compressor from surging, and a part of the pressurized air is supplied to the gas turbine outlet. The amount of fuel supplied to the boiler body is reduced by an amount corresponding to the amount of air passing through the gas turbine bypass duct and bypassed to the gas turbine outlet. By controlling so as to respond, while avoiding the surging of the gas turbine compressor, the load drop rate of the pressurized fluidized bed boiler is increased, the plant operation according to the power demand becomes possible, and the safety of the equipment is improved. And stable combustion can be continued.
[0046]
Claims of the present application2According to the described invention, by lowering the fluidized bed height in accordance with the throttle amount of the fuel, in addition to the effects of the invention, the temperature change of the fluidized bed can be eliminated. Claims of the present application3When the pressure ratio of the gas turbine compressor rises to a predetermined value or more, a part of the compressed air is opened by opening the on-off valve of the gas turbine bypass duct as a protective operation against surging of the compressor. To the gas turbine outlet, and increase the amount of pressurized air passing through the gas turbine compressor by an amount corresponding to the amount of air passing through the gas turbine bypass duct and bypassing to the gas turbine outlet. By controlling so that the amount of fuel to be input and the amount of pressurized air correspond, surging of the gas turbine compressor can be avoided, the safety of the equipment can be improved, and stable combustion can be continued.
[0047]
Claims of the present application4When the pressure ratio of the gas turbine compressor rises to a predetermined value or more, the gas turbine bypass duct on-off valve is opened as a protective action against surging of the compressor, and a part of the pressurized air is When the boiler load is high and the compressor passing air flow rate is close to the upper limit value, the fuel supply amount to the boiler body is bypassed to the gas turbine outlet through the gas turbine bypass duct. When the boiler load is low and the amount of fuel input to the boiler is close to the lower limit, the amount of pressurized air passing through the gas turbine compressor is passed through the gas turbine bypass duct to the gas. Increase by an amount corresponding to the amount of air to be bypassed to the turbine outlet. Fuel quantity and compressed air amount to be introduced into it by controlling so as to correspond, in addition to the effect of the invention, it is possible to continue a more stable combustion.
[0048]
Claims of the present application5When the pressure ratio of the gas turbine compressor rises to a predetermined value or more, the gas turbine bypass duct on-off valve is opened as a protective action against surging of the compressor, and a part of the pressurized air is And the operation of reducing the amount of fuel supplied to the boiler body according to the amount of air passing through the gas turbine bypass duct and bypassing the gas turbine outlet, and the operation of increasing the amount of pressurized air passing through the compressor In addition to the effects of the above invention, the control responsiveness is further improved.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing the principle of the present invention.
FIG. 2 is an explanatory diagram showing an embodiment of the present invention.
FIG. 3 is an explanatory view showing another embodiment of the present invention.
FIG. 4 is an explanatory diagram showing the principle of the present invention.
FIG. 5 is an explanatory view showing another embodiment of the present invention.
FIG. 6 shows the present invention.Reference exampleFIG.
FIG. 7 is an explanatory view showing a pressurized fluidized bed boiler apparatus to which the present invention is applied.
FIG. 8 is an explanatory diagram showing static characteristics of a pressurized fluidized bed boiler apparatus to which the present invention is applied.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Boiler load request signal, 2 ... Fuel demand function generator, 3 ... Fuel injection operation machine, 4 ... Air ratio setting device, 5 ... Delay characteristic function generator, 6 ... Air flow rate adjustment mechanism, 7 ... Boiler inflow air flow rate 8 ... Boiler necessary air flow signal, 9 ... Comparator, 10 ... Controller, 11 ... Gas turbine bypass valve, 12 ... Load change rate signal, 13 ... Opening request signal generator, 21 ... Boiler load request signal, DESCRIPTION OF SYMBOLS 22 ... Fuel demand function generator, 23 ... Fuel reduction command signal by surge generation signal, 24 ... Subtractor, 25 ... Fuel injection operation device, 26 ... Adder, 27 ... Air flow rate addition command signal by surge generation signal, 28 ... Air flow signal, 29 ... Comparator, 30 ... Controller, 31 ... Air flow rate adjusting mechanism, 32 ... Calculator, 33 ... Surge generation signal, 34 ... Plant load signal, 41 ... Compressor inlet pressure reducing valve, 42 ... Air compression Machine, 43 ... Compression Outlet valve, 44 ... Compressed air bypass valve, 45 ... Combustor, 46 ... High pressure gas stop valve, 47 ... Gas turbine, 48 ... Exhaust silencer, 49 ... Booster fan, 50 ... Pressure vessel, 51 ... Hot air generator, 52 ... Wind box, 53 ... fluidized bed, 54 ... furnace, 55 ... primary cyclone, 56 ... secondary cyclone, 57 ... gas turbine bypass piping, 58 ... gas turbine bypass valve, 59 ... decompression orifice, 60 ... high pressure exhaust gas duct, 61 ... Air duct, 62 ... exhaust duct, 64 ... branch duct, 65 ... air compression bypass duct, 66 ... open / close valve, 67 ... gas turbine bypass duct, 71 ... gas turbine compressor, 72 ... air flow rate adjusting mechanism, 73 ... compressor outlet valve 74 ... Boiler pressure vessel, 75 ... Boiler body, 76 ... High pressure exhaust gas duct, 77 ... Gas turbine inlet valve, 78 ... Star bottle bypass valve, 79 ... gas turbine body, 80 ... exhaust duct, 81 ... chimney, 82 ... air duct, 83 ... Gas turbine bypass duct.

Claims (5)

A pressure vessel that houses the boiler body, a gas turbine compressor that supplies pressurized air to the pressure vessel via an air duct, and a high-pressure exhaust gas that is discharged from the boiler body and supplied via a high-pressure exhaust duct In a control method of a pressurized fluidized bed boiler apparatus having a gas turbine, an exhaust duct that discharges the exhaust gas from the gas turbine, and a gas turbine bypass duct having an on-off valve that connects the exhaust duct and the air duct When the load of the boiler device is lowered, the amount of pressurized air passing through the gas turbine compressor is first controlled in a range equal to or greater than the surging limit value of the compressor according to the load change rate, and then provided to the gas turbine bypass duct. Opening the on-off valve and bypassing part of the pressurized air to the gas turbine outlet, Pressurized air amount supplied to the boiler body by adjusting the opening of the serial-off valve, controlled to the required amount corresponding to the amount of fuel injected into the boiler body, further the pressure ratio of the gas turbine compressor predetermined When the pressure rises above the value, as a protective action against the surging of the compressor, the gas turbine bypass duct on-off valve is opened to bypass a part of the pressurized air to the gas turbine outlet, and the fuel supply amount to the boiler body Is controlled so that the amount of fuel supplied to the boiler body corresponds to the amount of air, and is throttled by an amount corresponding to the amount of air that passes through the gas turbine bypass duct and is bypassed to the gas turbine outlet. Control method of pressure fluidized bed boiler device. The fuel or air of the pressurized fluidized bed boiler apparatus according to claim 1 , wherein the fluidized bed height is lowered by adjusting a pressurized air amount or a flow velocity supplied to the boiler body in accordance with a throttle amount of the fuel. Quantity control method. 2. The control method for a pressurized fluidized bed boiler apparatus according to claim 1 , wherein when the pressure ratio of the gas turbine compressor rises to a predetermined value or more, the on-off valve of the gas turbine bypass duct serves as a protection operation against surging of the compressor. And a part of the pressurized air is bypassed to the gas turbine outlet, and the amount of pressurized air passing through the gas turbine compressor is equivalent to the amount of air passing through the gas turbine bypass duct and bypassing to the gas turbine outlet. And a control method for the pressurized fluidized bed boiler device, wherein the amount of air supplied to the boiler body is controlled to correspond to the amount of fuel. 2. The control method for a pressurized fluidized bed boiler apparatus according to claim 1 , wherein when the pressure ratio of the gas turbine compressor rises to a predetermined value or more, the on-off valve of the gas turbine bypass duct serves as a protection operation against surging of the compressor. When the boiler load is high and the compressor passing air flow rate is in the vicinity of the upper limit value, the fuel supply amount to the boiler body is changed to the gas turbine bypass duct. If the boiler load is low and the amount of fuel input to the boiler body is near the lower limit, the amount of pressurized air passing through the gas turbine compressor is reduced. Equivalent to the amount of air that passes through the gas turbine bypass duct and bypasses to the gas turbine outlet. It is increased by an amount, fuel amount and the method of controlling a pressurized fluid Doso boiler system air amount and controls to correspond supplied to the boiler body. 2. The control method for a pressurized fluidized bed boiler apparatus according to claim 1 , wherein when the pressure ratio of the gas turbine compressor rises to a predetermined value or more, the on-off valve of the gas turbine bypass duct serves as a protection operation against surging of the compressor. Opening the valve and bypassing a part of the pressurized air to the gas turbine outlet, and reducing the amount of fuel supplied to the boiler body according to the amount of air passing through the gas turbine bypass duct and bypassing to the gas turbine outlet And a method for controlling the pressurized fluidized bed boiler apparatus, wherein the control is performed so that the amount of fuel supplied to the boiler body and the amount of air correspond to each other by simultaneously performing an operation of increasing the amount of pressurized air passing through the compressor.

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