JPH08240302A - Controller for temperature of bed in furnace - Google Patents

Abstract

PURPOSE: To maintain temperature in each section, at a preset value, by a method wherein output of a temperature-presetting device is subtracted from outputs of temperature sensors at the sections by subtracters, rotating speed- correcting signals each are generated so that outputs of the subtracters can be made equal to zero through function generators, and each rotating speed of fuel feeders is regulated. CONSTITUTION: In a pressurized fluidized-bed boiler, outputs of temperature sensors 1, 2 at an evaporator-bed part and a superheater-bed part are delivered to a subtracter 4 for average temperature through an average-operating device 3, and a deviation from an output of a temperature-presetting device 27 is found. This deviation signal is delivered to a PI controller 10 through a PI controller 5, an adder 7 and a subtracter 8, and its output is respectively delivered to adders 25, 26 through multipliers 13, 14, as rotating speed control signals 13s, 14s of rotary feeders 02, 03. A fuel-requiring signal 6s is inputted to the adder 7, and outputs of presetting devices 11, 12 are respectively inputted to the multipliers 13, 14. On the other hand, outputs of tachometers 19, 20 for the rotary feeders 02, 03 are delivered to the subtracter 8 through the adder 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a furnace bed temperature control device applied to a pressurized fluidized bed boiler.

[0002]

2. Description of the Related Art A system diagram of a conventional pressurized fluidized bed boiler is shown in FIG.
Shown in It is put into the hopper 01 from the coal crusher. The outlet of the hopper 01 is connected to a distributor 04 via a fuel feeder (rotary feeder or rotary valve) 02.
Similarly, it is connected to the distributor 05 via the rotary feeder 03. Further, a distributor air line is connected to the distributors 04 and 05. At the outlet of the distributor 04, the bed portion of the fluidized bed boiler furnace body 08 is divided by the fuel transfer pipe 06,
Connected to one evaporator bed zone. Similarly, the outlet of the distributor 05 is connected to the other superheater bed zone by a fuel carrying pipe 07.

FIG. 4 shows a bed temperature control device in the furnace.

The outputs of the temperature sensors 1 and 2 are the average calculator 3,
The temperature is sequentially sent to the average temperature subtractor 4, the PI controller 5, the adder 7, the subtractor 8, and the PI controller 10. The output of the PI controller 10 is sent to the operation device 15 of the rotary feeder 02 via the multiplier 13. Similarly, the output of the PI controller 10 passes through the multiplier 14 and the rotary feeder 0.
3 is sent to the operation device 16. The output of the temperature setting device 21 is sent to the subtractor 4. The fuel request signal 6s is sent to the adder 7. The output of the revolution counter 19 of the rotary feeder 02 is sent to the subtractor 8 via the adder 9. Similarly, the output of the revolution counter 20 of the rotary feeder 03 is sent to the adder 9. The output of the setter 11 is sent to the multiplier 13, and the output of the setter 12 is sent to the multiplier 14.

In the above, the bed temperatures of the evaporator and the superheater are measured by the thermocouple temperature sensors 1 and 2. This temperature signal is averaged by the averaging unit 3, the subtractor (comparator) 4 compares it with the specified temperature signal from the temperature setting unit 21, and the proportional-integral (PI) controller 5 calculates the average bed temperature as the specified temperature signal. The signal is arithmetically output so as to match with.

On the other hand, a correction signal from the PI controller 5 for keeping the bed temperature at a specified value is added by the adder 7 to the fuel request signal 6s corresponding to the boiler load (amount of generated steam),
It becomes a rotation speed (fuel amount) request signal of the rotary feeders (valves) 02 and 03. This signal is compared in the signal comparator 8 with the signal obtained by adding the outputs of the rotary valve revolution speed meters 19 and 20 in the adder 9 so that the proportional-integral (PI) controller 10 makes the revolution speed suitable for the fuel demand. Is calculated,
It becomes a control signal. This signal passes through a corrector (corrects the fixed gain difference of the rotary valve, the carrier pipe, etc.) composed of multipliers 13 and 14 and setters 11 and 12, and controls the rotation speed of the rotary valve. Signal 13s,
It becomes 14 s and is sent to the operation devices 15 and 16. The rotation speed of the rotary valve is changed by this signal, the fuel is increased or decreased, and fuel is supplied to the boiler according to the load of the boiler (fuel request signal 6s) and for keeping the bed temperature at a specified value.

[0007]

In the pressurized fluidized bed boiler, by controlling the bed temperature in the furnace at a specified value and making the temperature distribution uniform, the agglomeration of the fuel is prevented and the desulfurization effect in the furnace is improved. There is a need.

The above-mentioned conventional bed temperature control device controls the supply amount (rotation speed) from each fuel feeder (rotary valve) so as to make the fuel transfer into the furnace uniform. However, the supply of the fuel feeder (rotary valve) has a problem that the difference in the bulk density of the fuel powder causes a difference in the actual fuel supply amount, resulting in an imbalance (non-uniformity) in the bed temperature. It was

[0009]

The present invention employs the following means to solve the above-mentioned problems.

That is, as a bed temperature control device in the furnace, a fluidized bed boiler furnace main body in which the bed portion in the furnace is divided into a plurality, a fuel feeder for supplying powdered fuel to each of the above sections, and each of the above sections Temperature sensor, an average calculator for receiving the output of the temperature sensor, a temperature setter, an average temperature subtractor for receiving the outputs of the average calculator and the temperature setter, and a tachometer for the fuel feeder. And a rotation speed control means for transmitting a rotation speed control signal to each of the fuel feeders, which receives the output of the average temperature subtractor and the rotation speed meter and a fuel request signal, and the temperature sensor and the temperature. A subtracter that receives the output of the setter, a function generator that receives the output of the subtractor and outputs a rotation speed correction signal, and a rotation speed control signal that receives the output of the function generator It provided an adder calculated for.

[0011]

In the above invention, the output of the temperature setter is subtracted from the output of the temperature sensor of each section and output. Then, it is sent to each function generator and a rotation speed correction signal is generated so that the output of the subtractor becomes zero. This signal is added to the rotation speed control signal by each adder to become a corrected rotation speed control signal, which is sent to each fuel feeder. The rotation of the fuel feeder is adjusted by the corrected rotation speed control signal, and the temperature of each section is maintained at the output of the temperature setter.

In this way, the temperature of each section of the bed is made uniform.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. It should be noted that the parts described in the conventional example are denoted by the same reference numerals and the description thereof is omitted, and the parts relating to the present invention will be mainly described.

Temperature sensor 1 in the evaporator bed (zone)
The output of the temperature sensor 2 in the superheater bed is sent to the average temperature subtractor 4 via the average calculator 3. Temperature setter 21
Is output to the subtractor 4.

The output of the subtracter 4 is sent to the PI controller 10 through the PI controller 5, the adder 7 and the subtractor 8 in that order. The output of the PI controller 10 passes through the multiplier 13 and becomes the rotation speed control signal 13s of the rotary feeder 02, which is sent to the adder 25. Similarly, the PI controller 10
Is output to the adder 26 through the multiplier 14 as a rotation speed control signal 14s for the rotary feeder 03.

Further, the fuel request signal 6s is inputted to the adder 7. Further, the multipliers 13 and 14 have setting devices 11 and 12, respectively.
The output of each is input. Rotary feeder 0
The output of the tachometer 19 of 2 is sent to the subtracter 8 via the adder 7. Similarly, the output of the revolution counter 20 of the rotary feeder 03 is sent to the adder 9.

As described above, the PI controller 5, the adder 7, the subtractor 8, the PI controller 10, the multipliers 13 and 14, and the setters 11 and 12 are the rotation speed control means.

The outputs of the temperature sensors 1 and 2 are sent to subtractors 21 and 22, respectively. The output of the temperature setter 21 is sent to the subtracters 21 and 22, respectively. The output of the subtractor 21 is sent to the operation unit 15 of the rotary feeder 02 via the function generator 23 and the adder 25. Similarly, the output of the subtractor 22 is sent to the operation unit 16 of the rotary feeder 03 via the function generator 24 and the adder 26.

In the above, the temperature sensors 1, 2 of each section
From the output of the temperature setter 21 to the subtractor 21, 22
Is subtracted and output. Then, it is sent to the respective function generators 23 and 24, and the subtracters 21 and 2 having the characteristics as shown in FIG.
A rotation speed correction signal is generated so that the output of 2 becomes zero (α is appropriately set in actual operation). This signal is added to the rotation speed control signals 13s and 14s by the adders 25 and 26, and becomes a corrected rotation speed control signal, which is sent to the operation devices 15 and 16 of the respective rotary feeders. The rotary feeder 0 is driven by the corrected rotational speed control signal.
The rotation of Nos. 2, 03 is adjusted, and the temperature of each section is maintained at the output of the temperature setter.

In this way, the temperature of each section of the bed is made uniform.

That is, in addition to the amount of fuel charged to the fluidized bed boiler in proportion to the boiler load (evaporation amount), the amount of fuel is injected so that the average bed temperature becomes a specified value. At this time, regarding the cause of the imbalance that occurs during operation, such as the change in the bulk density of the fuel powder, the temperature difference between each part is detected, and the correction is added by this, so that the temperature in each section becomes uniform. Retained.

Multipliers 13 and 14 and a setter 1 for correcting a mechanical unbalance factor provided in the above system diagram.
The numbers 1 and 12 may be omitted. Although it is possible to control the evaporator and superheater bed temperatures independently, the proportional-integral controllers 5, 10 and the comparators 4, 8 and the adder 9 are independently increased by a multiple, Economical efficiency and reliability are poor.

[0023]

As described above, according to the present invention, the temperature of each section of the bed in the furnace is kept uniform even if it is subjected to a disturbance due to a change in the bulk density of the powdered fuel, and the performance of the boiler is improved. Can be improved.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of an in-furnace bed temperature control device according to an embodiment of the present invention.

FIG. 2 is an explanatory view of the operation of the same embodiment.

FIG. 3 is a system diagram of a fluidized bed boiler of the same example and a conventional example.

FIG. 4 is a block diagram showing a configuration of an in-furnace bed temperature control device of the conventional example.

[Explanation of symbols]

 01 Hopper 02, 03 Feeder 04, 05 Distributor 06, 07 Conveying pipe 08 Fluidized bed boiler furnace body 1, 2 Temperature sensor 3 Average calculator 4 Average temperature subtractor 5, 10 PI controller 7 Adder 8, 21, 22 Subtraction Device 9, 25, 26 Adder 11, 12 Setting device 13, 14 Multiplier 15, 16 Rotating operation device 19, 20 Revolution counter 23, 24 Function generator 27 Temperature setting device

Claims (1)

[Claims] 1. A fluidized bed boiler furnace body in which a bed portion in the furnace is divided into a plurality of parts, a fuel feeder for supplying powdered fuel to each of the above sections, and a temperature sensor provided in each of the above sections, An average calculator for receiving the output of the temperature sensor, a temperature setter, an average temperature subtractor for receiving the outputs of the average calculator and the temperature setter, a tachometer of the fuel feeder, and an average temperature subtractor, In a reactor bed temperature control device having a rotation speed control means for sending a rotation speed control signal to each of the fuel feeders, which receives the output of the rotation speed meter and a fuel request signal, a subtractor for receiving the outputs of the temperature sensor and the temperature setter. And a function generator that receives the output of the subtractor and outputs a rotation speed correction signal, and an adder that receives the output of the function generator and adds to the rotation speed control signal. In-furnace bed temperature control device.