JP3670824B2 - Fluidized bed height control method for pressurized fluidized bed boiler - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fluidized bed bed height control method for a pressurized fluidized bed boiler, and more particularly to a fluidized bed bed height control method for a pressurized fluidized bed boiler comprising a plurality of fluidized material storage containers.
[0002]
[Prior art]
A pressurized fluidized bed boiler is generally provided with a plurality of fluidized material storage containers because the volume of the fluidized material storage container is smaller than the volume of the furnace of the pressurized fluidized bed boiler.
A conceptual diagram of the fluidized bed bed height control system of such a pressurized fluidized bed boiler is shown in FIG. A conventional layer height control setting arithmetic circuit is shown in FIG.
[0003]
FIG. 3 shows the configuration of a pressurized fluidized bed boiler according to an embodiment of the present invention in which two fluidized material storage containers are provided. To explain the known part, 50 is a furnace and is stored on both the left and right sides. Containers 42A and 42B are disposed. Between the two, the bottoms of the storage containers 42A and 42B and the bottom of the fluidized bed 43 in the furnace 50 are communicated, and the fluidized materials 41A and 41B are intermittently fluidized by the opening and closing control of the fluidized material charging L valves 44A and 44B. The passages 55 and 56 introduced into the gas passage 43 are communicated with the upper portions of the storage containers 42A and 42B and the fluidized bed 43 in the furnace 50, and the fluidized material is returned from the fluidized bed 43 by suction control of the ejectors 40A and 40B. The discharge passages 57 and 58, the ejector outlet passages 61 and 62 opened at the top of the furnace 50, and the negative pressure passages 63 and 64 communicating between the tops of the storage containers 42A and 42B from the side portions of the ejectors 40A and 40B.
The fluid supply L valves 44A and 44B are intermittently controlled to open and close by L valve drive valves 51 and 52, and the air introduced into the ejectors 40A and 40B has a flow rate by opening and closing the ejector flow rate adjusting valves 53 and 54. It is controlled and the fluid flow rate is adjusted.
[0004]
Next, the control operation of the fluidized bed bed height H in such an apparatus is performed by returning the fluidized material between the introducing passages 55 and 56 and the discharging passages 57 and 58 between the fluidized material storage containers 42A and 42B and the furnace 50. First, when the bed height rises, the fluidic material storage containers 42A, 42B of the A system and the B system are opened and closed by intermittently opening / closing the drive valves 51, 52 of the fluidic material charging L valves 44A, 44B. When the fluidized materials 41A and 41B are transferred to the furnace 50 through the introduction passages 55 and 56 and the height of the bed is lowered, the fluid material suction ejector flow rate adjusting valves 53 and 54 are opened, and suction by the ejectors 40A and 40B is performed. By reducing the pressure in the storage containers 42A and 42B by the negative pressure effect, the fluid material can be sucked into the storage containers 42A and 42B from the furnace 50 through the discharge passages 57 and 58.
[0005]
FIG. 2 shows an arithmetic circuit for performing such a layer height control operation. In this circuit, an L valve for setting a fluid introduction interval is provided on each of the storage container 42A side (A system) and the storage container 42B side (B system). Drive valve opening time setting circuits A1 and B1, L valve driving valve closing time setting circuits A2 and B2, and ejector flow rate setting circuits A3 and B3 for sucking the fluidized material are provided.
Each setting circuit has the same circuit configuration. For example, the L valve driving valve opening time setting circuit A1 will be described. From the function generator 4 having the boiler input command value 1 as an input, the L valve driving valve opening time reference is set. The setting signal 4 a is output to the first multiplier 7. Also, an open time correction signal 5a based on the output change rate is output from the function generator 5 having the output change rate 2 as an input, multiplied by the reference setting signal 4a and the multiplier 7, and the first correction reference setting signal 7a. Is output to the second multiplier 8.
[0006]
Next, an open time correction signal 6a based on the layer height control deviation is output from the function generator 6 having the layer height control deviation 3 as an input, and the correction signal 6a is used as the first correction reference setting signal 7a and the second multiplier. The second correction reference setting signal 9 ′ multiplied by 8 and output from the second multiplier 8 is used as an L valve drive valve opening time setting signal.
Similarly, for the other valve height control setting signals such as the L valve drive valve closing time setting signal and the ejector flow rate setting signal, the reference setting based on the boiler input command value is multiplied by the output change rate and the correction coefficient based on the layer height control deviation. Is set.
Then, as an action of each layer height control setting signal, when the L valve drive valve opening time setting time is increased and the closing time setting time is decreased, the fluidized material charging speed is increased, while when the ejector flow rate setting time is increased, The fluid material suction speed will increase.
[0007]
[Problems to be solved by the invention]
Since the conventional technique performs the layer height control by three input signals of the boiler input command, the output change rate, and the layer height control deviation, the L valve drive valves 51 of the left and right storage containers 42A and 42B in FIG. , 52 when there is a difference in fluid material charging capacity, and when there is a difference in fluid material suction capacity due to the ejector flow control valves 53, 54, each fluid material storage container 42A, 42B (A in the example of FIG. The amount of fluidized material in the two containers of the system and system B will be uneven.
For example, in the case where the A-system storage container 42A is inferior in the fluid material charging capacity and the fluid material suction capacity is superior, the A-system storage is performed every time the L valve drive valves 51 and 52 and the ejector flow rate control valves 53 and 54 are operated. When the amount of fluidized material in the container 42A is larger than the amount of fluidized material in the B-type storage container 42B, the difference increases, and as a result, the amount of fluidized material in the A-type storage container 42A becomes excessive. Furthermore, even if the ejector flow rate adjustment valve 53 is opened when the fluidized bed 43 of the furnace 50 is lowered, it becomes impossible to suck the fluid 41A into the A-system storage container 42A, and in the B-system storage container 42B. When the amount of the fluidized material is too small, there is a problem that even if the L valve drive valve 52 is opened when the bed height rises, the fluidized material 41B cannot be introduced from the B-system storage container 42B.
[0008]
In view of such technical problems, the present invention provides a storage container in which the amount of fluidizing material in the storage container does not become excessive or small even when there is a difference in the fluidizing material charging capacity or fluidizing material suction capacity of the storage container. It is an object of the present invention to provide a fluidized bed height control method for a pressurized fluidized bed boiler capable of smoothly sucking (refluxing) or charging a fluidized material from a container.
[0009]
[Means for Solving the Problems]
The present invention is a fluidized bed bed height control method of a pressurized fluidized bed boiler comprising a plurality of fluidized material storage containers,
Each storage container as a layer height control signal for setting the fluidized material input amount from the respective fluidized material storage container to the fluidized bed side of the boiler or the fluidized material return amount from the fluidized bed to the respective fluidized material storage container Generated by measuring the weight of the fluid material inside and multiplying by the correction signal generated in the direction in which the fluid material amount in one storage container approaches the fluid material amount in the other storage container based on the fluid material weight difference between the storage containers Using the set signal, the bed height is controlled in the direction in which the amount of fluid material in both storage containers finally matches .
[0010]
According to this invention, even when there are instrumental differences in the flow material charging capacity and suction (reflux) capacity of each system of the plurality of storage containers, the weight of the flow material between the storage containers can be equalized.
More specifically, in the fluidized bed bed height control method for a pressurized fluidized bed boiler, each bed height control setting signal (L valve drive valve opening) determined by the boiler input command value, the output change rate, and the bed height control deviation. For each signal of the closing time setting and ejector flow rate setting), there is provided a means for obtaining a fluid material weight difference between the storage containers, and the respective layer height control settings are corrected by the weight difference. This makes it possible to equalize the weight of the fluid material between the storage containers even when there are differences in the fluid material charging capacity and suction capacity of each system for a plurality of storage containers.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Only.
[0012]
FIG. 3 shows a configuration of a pressurized fluidized bed boiler according to an embodiment of the present invention in which two fluidized material storage containers are provided.
As described above, reference numeral 50 in the figure denotes a furnace, and storage containers 42A and 42B are arranged on both the left and right sides thereof. Between the two, the bottoms of the storage containers 42A and 42B and the bottom of the fluidized bed 43 in the furnace 50 are communicated, and the fluidized materials 41A and 41B are intermittently fluidized by the opening and closing control of the fluidized material charging L valves 44A and 44B. The passages 55 and 56 introduced into the gas passage 43 are communicated with the upper portions of the storage containers 42A and 42B and the fluidized bed 43 in the furnace 50, and the fluidized material is returned from the fluidized bed 43 by suction control of the ejectors 40A and 40B. The discharge passages 57 and 58, the ejector outlet passages 61 and 62 opened at the top of the furnace 50, and the negative pressure passages 63 and 64 communicating between the tops of the storage containers 42A and 42B from the side portions of the ejectors 40A and 40B.
[0013]
The fluid supply L valves 44A and 44B are intermittently controlled to open and close by L valve drive valves 51 and 52, and the air introduced into the ejectors 40A and 40B has a flow rate by opening and closing the ejector flow rate adjusting valves 53 and 54. It is controlled and the fluid flow rate is adjusted.
[0014]
As described above, this configuration is a known part, and in the present invention, the storage containers 42A and 42B are particularly provided with measuring devices 61 and 62 for measuring the weight of the fluidized material in the containers, and the measurement is performed. The weights in the respective containers 42A and 42B are transmitted from the device through the weight transmitters 59 and 60 to the arithmetic circuit shown in FIG.
[0015]
FIG. 1 shows an arithmetic circuit according to an embodiment of the present invention for performing such a layer height control operation. In such a circuit, a fluidized material 41A, a storage container 42A side (A system) and a storage container 42B side (B system) are provided. 41B shows that an L valve driving valve opening time setting circuit A1, B1 and an L valve driving valve closing time setting circuit A2, B2 for setting the introduction interval of 41B and an ejector flow rate setting circuit A3, B3 for sucking the fluidized material are provided. 2 is the same as the conventional arithmetic circuit shown in FIG. 2, but in this embodiment, in particular, the layer height control setting is set according to the difference in the weight of the fluid material in the fluid material storage containers 42A and 42B with respect to the conventional method shown in FIG. A circuit 20 for correction is added. This will be described in detail below.
Each of the setting circuits A1 to B3 has the same circuit configuration except that the double deviation is reversed, and for example, the boiler input command value 1 is input to explain the L valve drive valve opening time setting circuit A1. The function generator 4 outputs an L valve drive valve opening time reference setting signal 4 a to the first multiplier 7. Also, an open time correction signal 5a based on the output change rate is output from the function generator 5 having the output change rate 2 as an input, multiplied by the reference setting signal 4a and the multiplier 7, and the first correction reference setting signal 7a. Is output to the second multiplier 8.
Next, an open time correction signal 6a based on the layer height control deviation is output from the function generator 6 having the layer height control deviation 3 as an input, and the correction signal 6a is used as the first correction reference setting signal 7a and the second multiplier. The second correction reference setting signal 9 ′ multiplied by 8 and output from the second multiplier 8 is output to the third multiplier 15.
[0016]
And the characteristic part of this invention exists in the system | symbol shown by the code | symbol 20 shown in FIG. 1, The fluidized material weight measurement value 16 in A type | system | group fluidized material storage container 42A, and the fluidized material weight measured value 17 in B type | system | group fluidized material storage container 42B. Is a subtractor 18 that subtracts the A system weight measurement value 16 as positive and the B system weight measurement value 17 as negative, and inputs the difference between the fluid material weights in the A system and B system storage containers to the function generator 19. To do.
The function generator 19 outputs an A-system fluidized material L valve drive valve opening time setting correction signal 19a to the third multiplier 15 based on the weight difference (A−B). The correction signal 19 a is multiplied by the second correction reference setting signal 9 ′ to generate the A-system fluidized material L valve drive valve opening time setting signal 9 in the present invention.
[0017]
As a result, when the weight difference is positive (plus), in other words, when the weight of the A-system storage container 42A is larger than the weight of the B-system storage container 42B, the A-system fluidized material L valve drive valve opening time setting signal 9 works in the direction in which the opening time increases from the second correction reference setting signal, and when the weight difference is negative (in other words, the weight of the A system storage container 42A is greater than the weight of the B system storage container 42B). In the case where the amount is small, the L valve drive valve opening time setting signal 9 for introducing the A system fluidizing material works in a direction in which the opening time decreases compared to the second correction reference setting signal 9 '. The difference is reduced in the direction in which the amount of fluidized material in 42A approaches the amount of fluidized material in B-type storage container 42B, and the amount of fluidized material in both storage containers 42A, 42B finally works.
[0018]
Next, in the A system storage container L valve drive valve closing time setting circuit A2, contrary to the above, the A system weight measurement value 16 is made negative, and the B system weight measurement value 17 is made positive and subtracted by the subtracter 18. The correction signal 19a of the function generator 19 obtained based on the weight difference (−A + B) is smaller than the second correction reference set value 9 ′ when the weight of the A-system storage container 42A is large (small). It is set to work in the (increase) direction.
More specifically, when the weight of the A-system storage container 42A is larger than the weight of the B-system storage container 42B, the A-system fluidized material L valve drive valve closing time setting signal 10 is the second correction reference setting signal. When the weight of the A-system storage container 42A is smaller than the weight of the B-system storage container 42B, the A-system fluidized material L valve drive valve closing time setting signal 10 is It works in the direction in which the closing time increases from the second correction reference setting signal 10 ′, and in any case, the difference narrows in the direction in which the amount of fluid material in the A-system storage container 42A approaches the amount of fluid material in the B-system storage container 42B. As a result, the amount of fluidized material in both storage containers 42A and 42B finally works in the same direction.
[0019]
Also, the ejector flow rate setting circuit A3 of the A-system storage container 42A has a negative value of the A-system weight measurement value 16 and a positive value of the B-system weight measurement value 17 in the same manner as the A-system storage container L valve drive valve closing time setting circuit A2. When the weight of the A-system storage container 42A is large (small), the correction signal 19a of the function generator 19 obtained by subtracting by the subtractor 18 based on the weight difference (−A + B) is the second correction reference. It is set to work in the direction of decreasing (increasing) from the set value 13 ′.
[0020]
Contrary to the A system (A1), the L valve drive valve opening time setting circuit B1 of the B system storage container 42B has a negative value for the A system weight measurement value 16 and a subtraction device 18 with the B system weight measurement value 17 as positive. Is obtained based on the weight difference (−A + B).
In addition, the B system storage container L valve drive valve closing time setting circuit B2 and the ejector flow rate setting circuit B3 also have the A system weight measurement value 16 positive and the B system weight measurement value as opposed to the A system (A2, A3). It is set so as to be obtained based on the weight difference (A−B) after being subtracted by a subtracter as negative.
[0021]
Accordingly, each of the bed height control setting calculation circuits, that is, the A system fluidizing material L valve driving valve opening time setting circuit A1, the A system fluidizing material L valve driving valve closing time setting circuit A2, and the B system fluidizing material introduction L valve drive valve opening time setting circuit B1, B system fluid material charging L valve drive valve closing time setting circuit B2, A system fluid material suction ejector flow rate setting circuit A3, B system fluid material suction ejector flow rate setting circuit B3 In either case, the correction signal 19a is generated based on the difference between the weight of the A-system storage container 42A and the weight of the B-system storage container 42A ((A−B) or (−A + B)). In order to generate the setting signal by multiplying the correction signal generated in the direction in which the amount of fluid material in the container approaches the amount of fluid material in the other storage container, the amount of fluid material in both storage containers finally works in the same direction .
[0022]
That is, according to the present invention, by multiplying the correction signal from the storage container fluidized material weight difference ((A−B) or (−A + B)), the difference in fluid material charging capacity due to the L valve driving valve and the ejector flow rate regulating valve. Even when a difference occurs in the weight of the fluidized material in the A-system and B-system storage containers 42A and 42B due to the instrumental difference in the fluid material suction capacity, the bed height control setting is corrected in a direction to correct each instrumental difference ( When A-system fluid weight> B-system fluid weight, the A-system L valve drive valve open time is extended, the close time is shortened, and the A-system ejector flow rate setting is decreased, while the B-system L valve drive valve open time is reduced. The flow rate of the fluidized material in the storage container can be reduced by reducing the flow rate of the fluidized material in the storage container. Storage of fluidized material suction capacity due to instrumental error We can solve the problems of the vessel in the flow material weight difference expansion.
[0023]
【The invention's effect】
As described above, the present invention can be applied to each storage container without excessive or too small amount of fluid material in the storage container even when there is a difference in the fluid charging capacity or fluid material suction capacity of the storage container. The fluid material can be smoothly sucked (refluxed) or charged.
[Brief description of the drawings]
FIG. 1 is a diagram showing a layer height control setting arithmetic circuit according to an embodiment of the present invention.
FIG. 2 is a diagram showing a conventional layer height control setting arithmetic circuit;
FIG. 3 is a conceptual diagram of a fluidized bed bed height control system of a pressurized fluidized bed boiler.
[Explanation of symbols]
1 Boiler input command value 2 Output change rate 3 Layer height control deviation 9 A system L valve drive valve open time setting 10 A system L valve drive valve close time setting 11 B system L valve drive valve open time setting 12 B system L valve drive Valve closing time setting 13 System A ejector flow rate setting 14 System B ejector flow rate setting 16 Fluidized material weight measurement value 17 in System A fluid storage container 42A Fluidity material weight measurement value 50 in system B fluid storage container 42B 50 Furnace 42A, 42B Flow Material storage containers 41A, 41B Fluidic materials 44A, 44B Fluidic material charging L valves 51, 52 L valve drive valves 53, 54 Ejector flow rate adjustment valves

Claims (1)

In a fluidized bed height control method of a pressurized fluidized bed boiler comprising a plurality of fluidized material storage containers,
Each storage container as a layer height control signal for setting the fluidized material input amount from the respective fluidized material storage container to the fluidized bed side of the boiler or the fluidized material return amount from the fluidized bed to the respective fluidized material storage container Generated by measuring the weight of the fluid material inside and multiplying by the correction signal generated in the direction in which the fluid material amount in one storage container approaches the fluid material amount in the other storage container based on the fluid material weight difference between the storage containers A fluidized bed bed height control method, wherein the bed height is controlled in the direction in which the amount of fluidized material in both storage containers finally matches using the set signal .

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