JPH0454812B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a control method for a turbo compressor system, and is particularly applicable to a system incorporating a turbo compressor, such as a fuel cell power generation system. The present invention relates to a turbo compressor system control method for maintaining and controlling both turbine inlet gas temperature and pressure at appropriate values during startup (during temperature and pressure increases).

[Conventional technology]

Conventionally, the present applicant filed an application for a control method for a turbo compressor system (patent application No. 60-237477).
This will be explained with reference to Fig. 2. In the figure, a turbo compressor 2 that requires compressed air and uses exhaust gas from a load section 1 that discharges exhaust gas as a power source to forcefully feed air to the load section 1 is connected to a turbine 2a and a compressor 2.
A variable nozzle 2c is provided at the gas inlet to the turbine 2a, and the opening degree or angle of the gas passage portion can be changed. Compressa 2
A compressor discharge air pressure detector 4 is connected midway through the system air supply pipe 3 that guides the compressed air to the load section 1. An auxiliary combustion furnace 6 for supplementing the power of the turbine 2a of the turbo compressor 2 is installed in the middle of the system exhaust gas piping 5 that guides the exhaust gas from the load section 1 to the turbine 2a. A turbine inlet gas pressure detector 7 is connected to the system exhaust gas piping 5 . An auxiliary combustion fuel control valve 9 and a flow rate detector 10 are provided on the auxiliary combustion fuel pipe 8 leading to the auxiliary combustion furnace 6 . An auxiliary combustion air control valve 12 and a flow rate detector 13 are provided on the way of the auxiliary combustion air piping 11 branched from the system air supply piping 3 to the auxiliary combustion furnace 6 . 15 is a pressure setting value for the compressor discharge air control system 14;
17 indicates a pressure setting value for the turbine inlet gas pressure control system 16. The auxiliary combustion amount command value 18, which is the operational output of the pressure control system 16, corresponds to the auxiliary combustion fuel flow rate. The calculator 19 converts the auxiliary combustion amount command value 18 into an auxiliary combustion air flow rate in consideration of the excess air ratio. 2
1 is a flow rate setting value for the auxiliary combustion fuel flow rate control system 20, and 23 is a flow rate setting value for the auxiliary combustion air flow rate control system 22. The limiter 24 converts the auxiliary combustion amount command value 18 into a flow rate set value 2 of the auxiliary combustion fuel flow rate control system 20.
1, the auxiliary combustion air flow rate detector 13
The range of the auxiliary combustion fuel flow rate setting value 21 is limited by the flow rate detection value by , the upper and lower limits of the excess air ratio, and the like. When the limiter 25 also provides the calculation result of the calculator 19 as the flow rate setting value 23 of the auxiliary combustion air flow rate control system 22, the limiter 25 uses the flow rate detected by the auxiliary combustion fuel flow rate detector 10, the upper and lower limits of the excess air ratio, etc. , limits the range of the auxiliary combustion air flow rate set value 23. It should be noted that the functions of the limiters 24, 25, the computing unit 19, etc. are natural and commonly used when performing combustion control.

Next, the control method will be explained. In accordance with the flow rate detected by the auxiliary combustion fuel flow rate detector 10 and the auxiliary combustion fuel flow rate set value 21, the auxiliary combustion fuel flow rate control system 2
0 performs feedback control by manipulating the opening degree of the auxiliary combustion fuel control valve 9 so that the flow rate of the auxiliary combustion fuel flowing through the auxiliary combustion fuel pipe 8 and the flow rate set value 21 are equal. Similarly, the auxiliary combustion air flow rate control system 22 operates the opening degree of the auxiliary combustion air control valve 12 according to the flow rate detected by the auxiliary combustion air flow rate detector 13 and the auxiliary combustion air flow rate set value 23, Feedback control is performed so that the flow rate of auxiliary combustion air flowing through the air pipe 11 and the flow rate setting value 23 are equal. The compressor discharge air pressure control system 14 has a pressure setting value 15 therefor and a compressor discharge air pressure detector 4.
The angle or opening degree of the variable nozzle 2c is operated in accordance with the detected value by the compressor, and feedback control is performed so that the compressor discharge air pressure becomes equal to the pressure setting value 15. For example, if the turbine inlet gas pressure and temperature do not fluctuate, the variable nozzle 2c
This is based on the fact that if the opening degree or angle of the turbine 2a is increased, the power of the turbine 2a increases, the flow rate of air discharged from the compressor 2b increases, and the compressor discharge air pressure is increased. Further, the turbine inlet gas pressure control system 16 operates the auxiliary combustion amount command value 18 according to the pressure setting value 17 and the pressure detection value of the turbine inlet gas pressure detector 7, thereby adjusting the turbine inlet gas pressure and the pressure setting value. Feedback control is performed so that 17 becomes equal. For example, if the auxiliary combustion amount command value 18 is increased, the limiter 24, 2
5 and the arithmetic unit 19 to set the flow rate setting value 2 of the auxiliary combustion fuel and auxiliary combustion air flow rate control systems 20 and 22.
1 and 23 increase, the flow rates of the auxiliary combustion fuel and auxiliary combustion air flowing through the auxiliary combustion fuel and auxiliary combustion air pipes 8 and 11 are increased, and by combustion in the auxiliary combustion furnace 6, they are added to the gas in the system exhaust gas pipe 5. The reason is that the thermal energy and flow rate of the flue gas increases, which increases the temperature and pressure of the turbine inlet gas.

As described above, the system exhaust gas is guided from the load section 1 to the auxiliary combustion furnace 6 through the system exhaust gas piping 5, and the system exhaust gas is guided to the load section 1 through the system air supply piping 3.
Even if the flow rate and temperature of the system supply air introduced to the compressor fluctuates, the turbine inlet gas pressure and compressor discharge air pressure can always be maintained at or near a predetermined value.

[Problem that the invention seeks to solve]

In the conventional turbo compressor system control method as described above, the auxiliary combustion fuel and auxiliary combustion air flow rates depend only on the control by the turbine inlet gas pressure control system 16. Therefore, for example, when the combustion amount in the auxiliary furnace 6 increases, However, as the turbine inlet gas temperature increases, there is a problem that the temperature of the system exhaust gas pipe 5, the turbine 2a, etc. may exceed the heat-resistant limit temperature, especially transiently.

This invention was made in order to solve the above-mentioned problems, and it provides a turbo compressor system control that can suppress the turbine inlet gas temperature to below a predetermined value and at the same time suppress the turbine inlet gas pressure to below a predetermined value. The purpose is to obtain a method.

[Means for solving problems]

The control method for a turbo compressor system according to the present invention is provided with a calculator that multiplies the auxiliary combustion amount command value, which is the operational output of the turbine inlet gas pressure control system, by a certain ratio, and converts the calculation result if necessary. The ratio by which the auxiliary combustion amount command value is multiplied is determined by the turbine inlet gas temperature control system that feedback-controls the turbine inlet gas temperature to a predetermined value. The system was assumed to be operated by

[Effect]

In the control method of the turbo compressor system in this invention, if the turbine inlet gas temperature is higher (lower) than the temperature setting value for the turbine inlet gas temperature control system, the turbine inlet gas temperature control system adjusts the auxiliary combustion amount command value. Decrease (increase) the multiplied ratio. On the other hand, the turbine inlet gas pressure is higher (lower) than the pressure setting value for the turbine inlet gas pressure control system.
If so, the auxiliary combustion amount command value is decreased (increased) by the turbine inlet gas pressure control system.

By the above operation, the calculation result of the calculator that multiplies the auxiliary combustion amount command value and the ratio is increased or decreased, and if this calculation result is increased (decreased), the flow rate setting value for the auxiliary combustion fuel and auxiliary combustion air flow rate control system is increased or decreased. increases (decreases)
However, as the amount of combustion in the auxiliary combustion furnace increases (decreases), the turbine inlet gas temperature and turbine inlet gas pressure increase (decrease).

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. It should be noted that the same or corresponding parts as in FIG. 2 are given the same reference numerals and their explanation will be omitted. In FIG. 1, a turbine inlet gas temperature detector 26 is connected midway through the system exhaust gas piping 5 between the auxiliary combustion furnace 6 and the turbine 2a. 28 is a temperature setting value for the turbine inlet gas temperature control system 27, and the value is lower than the heat resistance limit temperature of the turbine 2a, auxiliary combustion furnace 6, etc., and lower than the maximum temperature of the turbine inlet gas temperature reached during steady operation of the turbo compressor system. It's also expensive. 29 is the turbine inlet gas temperature control system 2
7, and is the ratio by which the auxiliary combustion amount command value 18 is multiplied. This ratio 29 and auxiliary combustion amount command value 1
8 is multiplied by the arithmetic unit 30. The first limiter 31 functions as a limiter for the auxiliary combustion amount command value 18, the second limiter 32 functions as a limiter for the ratio 29 multiplied by the auxiliary combustion amount command value 18, and the third limiter 33 functions as a limiter for the ratio 29 multiplied by the auxiliary combustion amount command value 18. Functions as a limiter for calculation results.

Next, the control method will be explained. The turbine inlet gas pressure control system 16 operates the auxiliary combustion amount command value 18 via the first limiter 31 in accordance with the pressure setting value 17 and the pressure detection value by the turbine inlet gas pressure detector 7 . For example, if the pressure set value 17 is higher (lower) than the detected pressure value, the auxiliary combustion amount command value 18 is decreased (increased). The first limiter 31 limits the operation range of the auxiliary combustion amount command value 18, and when the auxiliary combustion amount command value 18 reaches the upper or lower limit of the first limiter 31, the turbine inlet gas pressure control system 16 actually functions. do not. The turbine inlet gas temperature control system 27 uses an arithmetic unit 30 to set a ratio 29 by which the auxiliary combustion amount command value 18 is multiplied to a second value in accordance with the temperature setting value 28 and the temperature detection value by the turbine inlet gas temperature detector 26. is operated via the limiter 32. For example, if the temperature set value 28 is higher (lower) than the detected temperature value, the ratio 29 is decreased (increased).
The second limiter 32 limits the operating range of the ratio 29, and when the ratio 29 reaches the upper or lower limit of the second limiter 32, the turbine inlet gas temperature control system 27 does not actually function.

Further, the third limiter 33 limits the range of the result of multiplying the auxiliary combustion amount command value 18 and the ratio 29 by the calculator 30.
When the calculation result reaches the upper limit or lower limit of the third limiter function 33, the turbine inlet gas temperature control system 27 and the turbine inlet gas pressure control system 16 do not actually function. The calculation result of the calculation unit 30 is sent to the limiters 33, 24, 25 or the calculation unit 19.
The flow rate setting values 21 and 23 for the auxiliary combustion fuel and the auxiliary combustion air are supplied to the flow control systems 20 and 22 for the auxiliary combustion fuel and the auxiliary combustion air. If the calculation result increases (decreases), the flow rate of fuel and air flowing through the auxiliary combustion fuel and auxiliary combustion air pipes 8 and 11 increases (decreases), and the amount of fuel and air flowing through the auxiliary combustion fuel and auxiliary combustion air piping 8 and 11 increases (decreases). The thermal energy etc. added to the system exhaust gas increases (decreases), and the turbine inlet gas temperature and turbine inlet gas pressure increase (decrease).

If the temperature detected by the turbine inlet gas temperature detector 26 remains lower than the turbine inlet gas temperature setting value 28 for a long time (this state is long during steady operation), the ratio 29 multiplied by the auxiliary combustion amount command value 18 will be Since it is increased by the inlet gas temperature control system 27 and held at the upper limit value in the second limiter 32, the flow rate set values 21 and 23 are influenced only by the auxiliary combustion amount command value 18. As a result, the turbine inlet gas pressure control system 16 operates in the same manner as described in the conventional example, and feedback controls the turbine inlet gas pressure to around the pressure set value 17.

On the other hand, if the pressure detected by the turbine inlet gas pressure detector 7 remains lower than the turbine inlet gas pressure set value 17 (pressure increase, etc.) for a long time, the auxiliary combustion amount command value 18 is increased by the turbine inlet gas pressure control system 16. , are held at the upper limit value in the first limiter 31, so the flow rate set values 21, 23 are influenced only by the ratio 29 multiplied by the auxiliary combustion amount command value 18. As a result, the turbine inlet gas temperature control system 27 operates the ratio 29 according to the temperature setting value 28 and the temperature detected by the turbine inlet gas temperature detector 26, that is, the flow rate setting values of the auxiliary combustion fuel and the auxiliary combustion air. 21 and 23 to feedback control the turbine inlet gas temperature to around the temperature set value 28.

As shown in the conventional example, the compressor discharge air pressure control system 14 controls the compressor discharge air pressure in the vicinity of the pressure setting value 15 by controlling the opening degree or angle of the variable nozzle 2c.

In the above embodiment, the opening degree of the variable nozzle 2c is controlled by the compressor discharge air pressure control system 14 as a means for controlling the compressor discharge air pressure to a predetermined value. A pipe may be provided, and an atmospheric release control valve may be provided in the middle of the atmospheric release pipe, and the opening degree of the atmospheric release control valve may be controlled. Furthermore, although the opening degree of the variable nozzle 2c is controlled by feedback control of the compressor discharge air pressure by the compressor discharge air pressure control system 14, it may also be controlled by feedback control according to the load. It may be a turbo compressor 2 other than the variable nozzle 2b, or it may be a turbo compressor system that does not have means for controlling the compressor discharge air pressure to a predetermined value.

Further, the turbine inlet gas pressure control system 16 in the above embodiment is made into a first turbine inlet gas pressure control system, and a turbine bypass pipe is provided which is branched from the system exhaust gas pipe 5, and a turbine bypass control valve is installed in the middle of this turbine bypass pipe. A second valve is provided to provide feedback control of the turbine inlet gas pressure to around a predetermined value by manipulating its opening degree.
It may also have a turbine inlet gas pressure control system. In this case, the turbine inlet gas pressure can be brought closer to the predetermined value more quickly. Also, the second
It is desirable that the pressure setting value of the first turbine inlet gas pressure control system is greater than the pressure setting value of the first turbine inlet gas pressure control system.

〔Effect of the invention〕

As is clear from the above description, this invention
The auxiliary combustion amount command value is operated by the turbine inlet gas pressure control system, the ratio by which the auxiliary combustion amount command value is multiplied is operated by the turbine inlet gas temperature control system, and the result of multiplying the auxiliary combustion amount command value by the ratio is calculated, if necessary. Since the converted value is given as the flow rate setting value to the auxiliary combustion fuel and auxiliary combustion air flow rate control system, both the turbine inlet gas pressure and the turbine inlet gas temperature are always at the predetermined value, within the predetermined range, or below the predetermined value. Can be actively suppressed.

Furthermore, by limiting the auxiliary combustion amount command value, the ratio, or the result of multiplying them using a limiter means, it is possible to prevent the flow rate setting values to the auxiliary combustion fuel and auxiliary air flow rate control system from becoming too large or too small. can.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram for explaining an embodiment of the present invention, and FIG. 2 is a circuit diagram for explaining a conventional control method for a turbo compressor system. 1...Load part, 2...Turbo compressor,
2a...Turbine, 2b...Compressor, 5...
... System exhaust gas piping, 6... Assist combustion furnace, 7... Turbine inlet gas pressure detector, 8... Fuel piping for assist combustion, 9, 12... Control valve, 10, 13... Flow rate detector, 11... Assist combustion Air piping for use, 16...Turbine inlet gas pressure control system, 17...Pressure setting value, 1
8... Assisting combustion amount command value, 20... Fuel flow rate control system for assisting combustion, 21, 23... Flow rate set value, 22... Air flow rate control system for assisting combustion, 26... Turbine inlet temperature detector, 27... Turbine Inlet gas temperature control system, 2
8... Temperature set value, 29... Ratio, 30... Arithmetic unit. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A turbo compressor consisting of a turbine driven by exhaust gas from a load section that requires air, and a compressor that is directly connected to the turbine and compresses and supplies the necessary air to the load section;
A system for guiding exhaust gas from the load section to the turbine; an auxiliary combustion furnace installed in the exhaust gas piping to supplement the power of the turbine; and a turbine inlet gas pressure detection system installed in the system exhaust gas piping between the auxiliary combustion furnace and the turbine. and a turbine inlet gas temperature detector, and auxiliary combustion fuel piping and auxiliary combustion air piping for supplying the fuel and air necessary for combustion in the auxiliary combustion furnace to the auxiliary combustion furnace, and the auxiliary combustion fuel piping and the auxiliary combustion air In a control method for a turbo compressor system that is equipped with a control valve and a flow rate detector in the middle of each piping, the opening degree of the control valve is controlled according to the flow rate detection value and the flow rate set value of the flow rate detector to control the above-mentioned flow rate. It is equipped with an auxiliary combustion fuel flow rate control system and an auxiliary combustion air flow rate control system that perform feedback control so that the detected value and the above-mentioned flow rate set value are equal, and the turbine inlet gas pressure control system detects the pressure of the turbine inlet gas pressure detector. The auxiliary combustion amount command value is operated according to the above pressure detection value and the turbine inlet gas pressure setting value, and feedback control is performed so that the above pressure detection value and the above pressure setting value are equal. The calculation result obtained by multiplying the quantity command value by a certain ratio is converted into a flow rate setting value for the auxiliary combustion fuel flow rate control system and the auxiliary combustion air flow rate control system, and is used as the temperature detection value of the turbine inlet gas temperature sensor. 1. A control method for a turbo compressor system, characterized in that feedback control is performed so that the detected temperature value and the temperature set value become equal by manipulating the ratio according to the temperature set value. 2. An auxiliary combustion amount command value which is the operational output in the turbine inlet gas pressure control system and a turbine inlet gas temperature control system, a ratio by which this auxiliary combustion amount command value is multiplied, and further a calculation in which the ratio is multiplied by the auxiliary combustion amount command value. 2. A turbo compressor system control method according to claim 1, wherein an upper limit value and a lower limit value are set for any of the results, and the operating range is limited by a limiter means. 3. A turbine bypass control valve is provided in the middle of the turbine bypass piping branched from the system exhaust gas piping, and the first turbine inlet gas pressure control system manipulates the auxiliary combustion amount command value so that the detected pressure value and the pressure set value become equal. At the same time, a second turbine inlet gas pressure control system operates the opening degree of the turbine bypass control valve according to the detected pressure value and the pressure set value to control the pressure set value and the detected pressure value. 2. A turbo compressor system control method according to claim 1, wherein feedback control is performed so that 4. The turbo compressor system control method according to claim 3, wherein the pressure setting value of the second turbine inlet gas pressure control system is larger than the pressure setting value of the first turbine inlet gas pressure control system. 5 A fuel limiter means is provided for setting an upper limit value and a lower limit value for the flow rate set value in the auxiliary combustion fuel flow rate control system, and for limiting the range of the above flow rate set value by the upper and lower limit values, and the above flow rate set value is The above-mentioned upper limit value and lower limit value are the values that have passed through a fuel limiter means, and the above-mentioned upper limit value and lower limit value are calculated based on the detected value of the air flow rate by a flow rate detector in the middle of the auxiliary air piping and the upper and lower limit values of the excess air ratio. 2. A method for controlling a turbo compressor system according to item 1. 6. Air limiter means is provided for setting an upper limit value and a lower limit value for the flow rate set value in the auxiliary combustion air flow rate control system, and for limiting the range of the above flow rate set value by the upper and lower limit values, and the above flow rate set value is The above-mentioned upper limit value and lower limit value are the values that have passed through the air limiter means, and the above-mentioned upper limit value and lower limit value are calculated based on the detected value of the fuel flow rate by a flow rate detector in the middle of the fuel piping for auxiliary combustion, and the upper and lower limit values of the excess air ratio. 2. A method for controlling a turbo compressor system according to item 1. 7 The temperature setting value of the turbine inlet gas temperature control system is lower than the heat-resistant limit temperature of the turbine, the auxiliary combustion furnace, the system exhaust gas piping from the auxiliary combustion furnace to the turbine, etc., and the temperature setting value of the turbine inlet gas temperature control system is lower than the heat resistance limit temperature of the turbine, the auxiliary combustion furnace, and the system exhaust gas piping from the auxiliary combustion furnace to the turbine, and the temperature setting value of the turbine inlet gas temperature control system is A method for controlling a turbo compressor system according to claim 1, wherein the temperature is higher than the maximum gas temperature.