JP6139762B1 - Powder parallel blowing system and powder parallel blowing method - Google Patents

Abstract

An object of the present invention is to control the supply amount of powder with high accuracy when switching a powder supply device provided with a blowing tank. A variable flow rate and a carrier gas amount control valve are controlled based on an opening degree of a valve corresponding to a preset powder flow rate setting value (FI), and a powder flow rate measured by a powder flow meter is measured. The pressurization control valve is controlled so that the actual measurement value approaches the powder flow rate setting value, and the weight of the powder in the blowing tank of the powder supply device A in operation among the plurality of powder supply devices is predetermined. Of the powder to be conveyed by the powder supply device B to the other powder supply device B by the control means of the powder supply device A (L1) or less (L1) FI_B), and the control means of the powder control apparatus B that has received FI_B starts conveying and supplying the powder, and controls the flow rate of the powder based on the received powder flow rate setting value. Control is performed so that the sum of the powder flow rate setting value (FI_A) of the supply device A and FI_B becomes a constant amount. [Selection] Figure 4

Description

  The present invention relates to a parallel blowing system for powder transported by a transport gas from a blowing tank and a method thereof, and more particularly, a gasification furnace such as a blast furnace, a thermal power plant or a chemical plant using a plurality of blowing tanks. The present invention relates to a powder parallel blowing system and a powder parallel blowing method for accurately controlling the amount of powder supplied at the time of switching a blowing tank.

  2. Description of the Related Art A combustion furnace that burns pulverized fuel such as pulverized coal supplied from a powder supply device having a blowing tank is known as a combustion furnace used for blast furnace equipment and the like. In this combustion furnace, the pulverized fuel is burned while being injected into the combustion furnace together with the carrier gas. Such a combustion method using pulverized coal is widely used for reasons such as high combustibility of the coal itself.

  In such a powder supply device, since there is a need to continuously supply pulverized fuel, a plurality of injection tanks are provided, and the pulverized fuel in one injection tank is emptied or a predetermined amount When the amount is less than that, the pulverized fuel can be continuously supplied by switching to a blowing tank sufficiently filled with another pulverized fuel.

  The concept of switching the blowing tank (hereinafter simply referred to as “tank”) will be described with reference to FIG. FIG. 1A shows a case where the pulverized fuel in one tank (tentatively referred to as “tank A”) is switched to another tank (temporarily referred to as “tank B”). Yes. As is clear from FIG. 1 (A), the total amount of pulverized fuel supplied before and after the switching of the tank largely fluctuates from 0% to 100% of the preset target value, so that stable operation is possible. could not.

FIG. 1B shows a concept of a control method at the time of tank switching proposed to solve the problem at the time of tank switching as shown in FIG. That is, when the pulverized fuel in the tank A becomes less than a predetermined amount, the pulverized fuel in the tank A is started to be supplied gradually from the tank B, and the lower limit value set in advance for the pulverized fuel in the tank A Control is performed so that the sum of the supply amount from the tank A and the supply amount from the tank B becomes a target value during a predetermined period until reaching the value (referred to as “switching period” in the figure). .
After the elapse of the switching period, the process shifts to single injection by the tank B, and the tank A is replenished with pulverized fuel from a storage tank (not shown) and waits until the next switching. By repeating this below, stable operation is realized. This method is hereinafter referred to as “parallel blowing” for convenience in this specification.

The prior art of such parallel blowing will be described next. FIG. 2 is a schematic diagram showing a first example of prior art of parallel blowing (see, for example, Patent Document 1).
Since the operation of the apparatus in FIG. 2 is described in Patent Document 1, detailed description thereof is omitted, but when the tank is switched, the blowing control valve (7B-1) of the tank (1-1) being blown is defined. While gradually closing to the opening degree, the blowing control valve (7B-2) of the standby tank (1-2) is gradually opened according to the blowing flow rate, and the tank is switched while monitoring the blowing flow rate from each tank. Is.

However, although it is described as “switching the blowing tank while monitoring the blowing flow rate from each pulverized coal blowing tank”, how to adjust the blowing control valve (1-2) according to the blowing flow rate ( It is not disclosed at all whether to switch while controlling the opening degree of 7B-2).
Judging from the description in the prior art section of Patent Document 1 (paragraphs 0002 and 0003), the blowing flow rate is determined based on the weight signal of the pulverized coal in the tank 1 detected by the weighing unit 3. 6 is considered to be controlled by adjusting the blowing tank pressure regulating valve 5.

  However, according to the description in paragraph 0009 and FIG. 3 (Patent Document 1), in this conventional example, the opening degree of the blowing control valve (7B-1) of the tank (1-1) is changed in the transition period of tank switching. When the valve (7B-2) of the standby tank (1-2) is gradually opened from 0% to 50% and both of them reach 50%. The blowing control valve (7B-1) of the tank (1-1) is fully closed, and the blowing control valve (7B-2) of the tank (1-2) is fully opened. In this case, the information on the flow rate of the blow-in from the tanks (1-1) and (1-2) is not used for opening control of the blow-in control valves (7B-1) and (7B-2).

  Furthermore, when the tank is switched, the amount of powder in the tank (1-1) is low, so the opening of the blowing control valve (7B-1) is gently closed from 100% to 50%. Even if it does, the blowing flow rate does not necessarily decrease gradually from 100% to 50% in proportion to that, but the blowing control valve (7B-2) of the tank (1-2) having a sufficient amount of powder. Even if the opening is gradually opened from 0% to 50% and the blowing flow rate is gradually increased from 0% to 50% in proportion thereto, the sum of the blowing flow rates is not necessarily 100% as calculated.

FIG. 3 is a schematic view showing a second example of the prior art of parallel blowing, and shows the main part of FIG. This is made to solve the problem of the first example of the prior art as described in Patent Document 1.
That is, at the time of tank switching, based on the actual measurement value of the total blowing amount (total blowing amount) from both tanks, only one tank is changed to the variable valve 4 (the “blowing control valve 7B” in Patent Document 1). The variable valve 4 of the other tank is not corrected by the above measured value.

This will be specifically described with reference to FIG. The basic flow rate control of the apparatus shown in FIG. 3 is that the flow rate controller 12 is variable based on the actual measured value of the powder flow rate measured by the flow meter 10 during the period when the tank 1a is blowing alone. This is done by correcting the opening of the valve 4a.
Next, when detecting that the weight of the powder in the tank 1a has become a certain value or less, the flow rate controller 12 gradually closes the variable valve 4a and simultaneously opens the variable valve 4b of the tank 1b. go. Then, the opening degree of only one of the variable valves 4a or 4b is corrected so that the actually measured value (of the total blowing amount) measured by the flow meter 10 becomes a set value. For example, the variable valve to be corrected may be selected so that the amount of powder transported per unit time is larger.

The reason for correcting only one of the variable valves is that when the amount of powder decreases, the blowing amount becomes unstable, so it is difficult to balance the blowing amounts of both tanks, and the total blowing amount is constant. This is because it becomes difficult to control the operation.
Thereafter, when the amount of the powder in the tank 1a becomes smaller than a predetermined value, the process shifts to single blowing by the tank 1b, and thereafter this is repeated in the same manner.
By doing in this way, it is said that there is no need to balance the blowing amounts of both tanks, and it is said that there is an effect that the total blowing amount can be kept constant accurately.

JP-A-8-295911 Japanese Patent Laid-Open No. 10-338349

However, since the method described in Patent Document 2 performs control by correcting only one of the variable valves, the open / close range of the valve must be widened, and the responsiveness is not good. There is a drawback of getting worse.
Moreover, the method of switching the variable valve to be controlled depending on conditions is complicated, and in some cases, the controllability may be deteriorated (see paragraph 0022 of Patent Document 2).
Furthermore, in the method described in Patent Document 2, the total blowing amount is measured by the flow meter 10, but the blowing flow rate for each tank cannot be measured individually in a state where parallel blowing is performed. . As is apparent from FIG. 3, the flow meter 10 is provided after the transfer pipes of the two tanks 1a and 1b merge.

Furthermore, although not described at all in Patent Document 2, it is necessary to consider the amount of carrier gas in the flow rate control of the powder. In order to ensure the stability of blowing, it is important to keep the ratio (solid-gas ratio) between the amount of powder and the amount of carrier gas constant. For this purpose, it is necessary to control the amount of carrier gas independently for each tank.
Such a problem can also occur when conveying powder other than pulverized fuel.
The present invention has been made in view of the above-described problems of the prior art, and is a powder for accurately controlling the amount of powder supplied at the time of switching of a powder supply apparatus equipped with a blowing tank. An object is to provide a parallel blowing system and a powder parallel blowing method.

  In order to solve the above-mentioned problems, a powder parallel blowing system according to the present invention includes a blowing tank filled with powder, a weighing device for detecting the weight of the powder in the blowing tank, and the blowing tank. A powder transfer pipe connected to a discharge port provided in the vicinity of the lower part, and a variable valve provided on the downstream side of the discharge port and capable of adjusting the amount of powder discharged from the discharge port by the opening of the valve And a pressurized gas is introduced into the blowing tank, and the powder in the blowing tank is discharged from the discharge port due to the pressure difference in the blowing tank and the pressure in the powder conveying pipe. A pressurization control valve that adjusts the pressure of the pressurized gas, a carrier gas amount control valve that controls the amount of the carrier gas when introducing a carrier gas for conveying the powder into the powder carrier pipe, Powder for measuring the flow rate of powder transported in the powder transport pipe A plurality of powder supply devices, each having a quantity measuring means and a control means for controlling the flow rate of the powder conveyed through the powder conveying pipe by controlling the opening of each valve, are connected in parallel. , A powder parallel blowing system for continuously feeding a constant amount of powder while switching or simultaneously operating the powder supply devices, wherein the control means sets a preset powder flow rate setting value. The pressure control valve controls the opening and closing of each valve based on the opening of the corresponding valve, and the measured powder flow rate measured by the powder flow rate measuring means approaches the powder flow rate set value. And when the weight of the powder in the blowing tank of one of the plurality of powder supply devices in operation is equal to or less than a predetermined value, the one powder The control means of the supply device controls the other powder with respect to the other powder supply device. The control unit of the other powder control device that has transmitted the powder flow rate setting value of the powder to be conveyed by the supply device and has received the powder flow rate setting value has started to receive and received the powder. The flow rate of the powder is controlled based on the powder flow rate setting value, and the sum of the powder flow rate setting value of the one powder supply device and the powder flow rate setting value of the other powder supply device is the above It is characterized by controlling to be a certain amount.

  With the above-described configuration, it is possible to control the amount of powder supplied at the time of switching each powder supply apparatus with high accuracy.

It is a figure for demonstrating the concept of powder parallel blowing. It is the schematic which shows the 1st example of the prior art of parallel blowing. It is the schematic which shows the 2nd example of the prior art of parallel blowing. It is the schematic which shows 1st Embodiment of the structure of the powder parallel blowing system which concerns on this invention. It is a block diagram which shows the hardware constitutions of a control part. It is a block diagram which shows the function structure of a control part. It is an example of the flowchart which shows the flow of the process which a powder flow rate control part performs. It is an example of the flowchart which shows the flow of the process which a tank switching control part performs. It is an example of the flowchart which shows the flow of the process which a valve opening / closing control part performs. 3 shows a look-up table that defines the relationship between the powder flow rate setting value (FI) and the variable valve opening (%). 3 shows a look-up table that defines the relationship between the powder flow rate setting value (FI) and the carrier gas amount control valve opening (%). It is an example of the flowchart which shows the flow of the process which a tank switching control part performs in the case of performing simultaneous parallel processing with one control part.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[First Embodiment]
FIG. 4 is a schematic diagram showing a first embodiment of the configuration of the powder parallel blowing system according to the present invention.
In FIG. 4, reference numerals 1a and 1b indicate blow tanks A and B filled with powder. Examples of the powder include pulverized coal.
Reference numerals 2a and 2b indicate the pressure inside the blowing tanks 1a and 1b (hereinafter simply referred to as the blowing tank 1, except for the case where a and b are specifically distinguished). Is applied to adjust the pressure of the pressurized gas for discharging the powder in the blowing tank 1 from the discharge port based on the pressure difference in the blowing tank 1 and the pressure in the powder transfer pipe 6 described later. This is a pressure control valve. Examples of the pressurized gas include inert gases such as nitrogen and air.

Reference numerals 3a and 3b indicate variable valves that are provided on the downstream side of the discharge port and that can adjust the amount of powder discharged from the discharge port by the opening of the valve. As an example of the variable valve 3, a trade name “Variable Valve” manufactured by Diamond Engineering Co., Ltd. can be used.
Reference numerals 4a and 4b denote weighing machines that detect the weight of the powder in the blowing tank 1. An example of the weighing instrument 4 is a load cell that converts a load into an electric signal.

Reference numerals 5a and 5b denote control units that control the flow rate of powder conveyed in a powder conveyance pipe 6 (to be described later) by controlling the opening degree of each valve described above. It is a form. The detailed function will be described later. For example, a general-purpose personal computer can be used.
Reference numerals 6a and 6b denote powder transfer pipes connected to the discharge port of the blowing tank 1 for transferring the powder discharged from the discharge port to a furnace or the like.

Reference numerals 7 a and 7 b indicate a lower valve for keeping the blowing tank 1 sealed. When the introduction of the pressurized gas is stopped when the blowing is stopped and the pressure in the blowing tank 1 decreases, the carrier gas and the powder flow back into the blowing tank through the powder conveying pipe due to the pressure of the carrier gas. Provided to prevent completely.
Reference numerals 8a and 8b denote powder flow meters that measure the flow rate of the powder conveyed through the powder conveyance pipe 6, and are one form of the powder flow rate measuring means.
Reference numerals 9a and 9b denote carrier gas amount control valves that control the amount of carrier gas when introducing carrier gas for conveying powder into the powder carrier pipe 6.

  The powder parallel blowing system according to the present invention includes the above-described blowing tank 1, pressurizing control valve 2, variable valve 3, weighing device 4, control unit 5, powder conveying pipe 6, lower valve 7, and powder flow meter 8. In addition, a plurality of powder supply devices (two in this description) provided with the carrier gas amount control valve 9 are connected in parallel, and each powder supply device is switched or operated simultaneously, while being constant with respect to the furnace. An amount of powder is continuously conveyed and supplied.

FIG. 5 is a block diagram showing a hardware configuration of the control units 5a and 5b shown in FIG.
As shown in FIG. 5, for example, the control unit 5a can be configured such that a CPU 51a, a ROM 52a, a RAM 53a, and a communication I / F (interface) 54a are connected by a system bus 55a. The external input unit 56a is a device for inputting data and the like from the outside. For example, a keyboard, a USB memory, or the like can be used.
The CPU 51a executes a predetermined program stored in the ROM 52a or the like using the RAM 53a as a work area to control the pressurization control valve 2a, variable valve 3a, lower valve 7a, and carrier gas amount control valve 9a of the powder supply device. By doing so, a desired amount of powder can be supplied to the furnace.

The communication I / F 54a is an interface for communicating with the control unit 54b via a network such as a LAN, and can include a LAN terminal, a modem, an antenna for realizing a wireless LAN, and a transceiver.
The control units 5a and 5b cooperate with each other by transmitting and receiving commands through communication, and can continuously convey and supply a certain amount of powder to the furnace.
Since the control unit 5b has the same hardware configuration as the control unit 5a, the description thereof is omitted.

FIG. 6 is a block diagram illustrating a functional configuration of the control unit 5. FIG. 6 shows functions related to the features of this embodiment.
The control unit 5 shown in FIG. 6 includes a powder flow rate acquisition unit 61, a powder flow rate control unit 62, a tank switching control unit 63, and a valve opening / closing control unit 64.

  Among these, the powder flow rate acquisition unit 61 acquires a specified amount of flow rate (a target value of the total amount of powder to be supplied to the furnace or the like) from the external input means 56, and powder based on the acquired specified amount. A function of setting and storing a flow rate set value (hereinafter referred to as “set value”) and a function of acquiring a powder flow rate actual value (hereinafter referred to as “actual value”) from the powder flow meter 8 are provided. The powder flow rate acquisition unit 61 has a function of transmitting a set value and / or an actual measurement value in response to a transmission request from the powder flow rate control unit 62, the tank switching control unit 63, and the valve opening / closing control unit 64.

Further, the powder flow rate control unit 62 is based on the set value and the actual measurement value acquired from the powder flow rate acquisition unit 61 so that the difference between the set value and the actual measurement value falls within a predetermined error. 64 has a function of instructing the control of the pressurization control valve 2 to 64.
FIG. 7 is an example of a flowchart showing the flow of processing performed by the powder flow rate control unit 62. This process starts when a set value reading start command is received from the tank switching control unit 63.

  The CPU 51 acquires the first set value from the powder flow rate acquisition unit 61 (S701). Next, an actual measurement value is acquired at the same timing (S702). Next, it is checked whether or not the difference between the set value and the actually measured value is smaller than a predetermined error (δ). If the difference is smaller (YES in S703), if the blowing is not stopped (NO in S704), The next set value is acquired (S705), the process returns to step S702, the actual measured value at that time is acquired, and it is checked whether or not the difference from the set value is smaller than δ (S703). If the blowing is stopped (YES in S704), the process is terminated.

On the other hand, if the difference between the set value and the actually measured value is δ or more in step S703 (NO in S703), it is necessary to adjust the opening degree of the pressurization control valve 2 to bring the actually measured value closer to the set value.
Therefore, when the actual measurement value is smaller than the set value (YES in S706), the opening of the pressurization control valve 2 is increased to increase the pressure in the blowing tank 1, and the flow rate of the conveyed powder is increased (S707). . Note that the opening degree control of the pressurization control valve 2 is performed by the powder flow rate control unit 62 instructing the valve opening / closing control unit 64 as described above. Then, the process returns to step S702, the actual measurement value at that time is acquired (S702), and it is checked whether or not the difference between the set value and the actual measurement value is smaller than δ.

In step S706, if the measured value exceeds the set value (NO in S706), the pressure in the blowing tank 1 is lowered by lowering the opening of the pressurization control valve 2, and the flow rate of the conveyed powder. (S708). Then, the process returns to step S702, the actual measurement value at that time is acquired (S702), and it is checked whether or not the difference between the set value and the actual measurement value is smaller than δ. Thereafter, the same processing is repeated. Note that δ can be appropriately set according to system requirements.
Through the above processing, the measured value of the powder flow rate can be brought close to the set value.

  Returning to FIG. 6, the tank switching control unit 63 determines the remaining amount of powder in the blowing tank 1 a of the currently operating powder supply apparatus A (representing a powder supply apparatus including the blowing tank 1 a, the same applies hereinafter). When the value becomes equal to or less than a predetermined value (for example, L1), a parallel blowing start command signal is sent to the other powder supply apparatus B on standby, and the powder supply apparatus A and the powder supply apparatus B are It is equipped with a function to convey a fixed amount (regulated amount) of powder continuously while operating in parallel. This is a characteristic function of the present invention.

After the powder supply device A is stopped from blowing under a predetermined condition, the powder supply device B has a function of continuously blowing and conveying a fixed amount (a prescribed amount) of powder.
The “predetermined condition” is, for example, when the remaining amount of the powder in the blowing tank 1a is equal to or lower than a predetermined lower limit (for example, L2 smaller than L1) or in the blowing tank 1a. It is conceivable that a predetermined time (for example, about 1 minute) elapses after the remaining amount of the powder reaches L1.

Further, the valve opening / closing control unit 64 adjusts the opening degree of the pressurization control valve 2 according to commands from the powder flow rate control unit 62 and the tank switching control unit 63, and controls the pressurization control valve 2 and the lower valve 7. It has a function to control opening and closing. Moreover, the function which sets the opening degree of the variable valve 3 and the conveyance gas amount control valve 9 based on the setting value (FI) acquired from the powder flow rate acquisition part 61 is also provided. The control of the valve opening / closing control unit 64 will be described later.
As mentioned above, in order to explain the function of the control unit 5 in an easy-to-understand manner, it has been described in each block. However, it is not always necessary to create a control program for each functional block, and these functions are controlled by a single program. Needless to say.

  FIG. 8 is an example of a flowchart showing a flow of processing performed by the tank switching control unit 63. The left side of FIG. 8 shows the flow of processing performed by the tank switching control unit 63a included in the control unit 5a, and the right side shows the flow of processing performed by the tank switching control unit 63b included in the control unit 5b. . The control unit 5a and the control unit 5b are communicably connected to each other, and perform processing while cooperating with each other.

  Hereinafter, processing performed by the tank switching control unit 63 will be described with reference to FIG. This process starts when the operator depresses a blow start button (not shown) after filling the blow tank 1 with powder. The process of the tank switching control unit 63b of the powder supply apparatus B (the flow on the right side in FIG. 8) starts simultaneously with the process of the tank switching control unit 63a of the powder supply apparatus A (the flow on the left side in FIG. 8). However, it is possible to start with a delay as long as the process of the tank switching control unit 63a is not shifted to step S805a.

A case where the powder supply apparatus A performs the blowing first will be described as an example. First, a command to open the pressurization control valve 2a and the lower valve 7a is issued to the valve opening / closing control unit 64a (S801a), and monitoring of the value of the weighing instrument 4a (hereinafter referred to as WI_A) is started (S802a). That is, monitoring of the weight of the powder remaining in the blowing tank 1a is started.
Next, the powder flow rate acquisition unit 61a is instructed to set a set value of the powder flow rate (hereinafter referred to as FI_A) to a specified amount, and blowing from the blowing tank 1a is started (S803a). .

After the start of blowing from the blowing tank 1a, while WI_A is larger than the predetermined value (L1) (NO in S804a), blowing is continued as it is (that is, without changing the set value).
Thereafter, when WI_A becomes equal to or less than L1 (YES in S804a), the flow shifts to parallel blowing with the blowing tank 1b.
In parallel blowing, while gradually reducing the amount of blowing from the blowing tank 1a, the amount of blowing from the blowing tank 1b is gradually increased so that the total amount of both blowing becomes a specified amount (a constant amount). Is to control.
Therefore, what is previously defined by a function (equation 1 described later) that gradually decreases FI_A during parallel blowing from the specified amount and stored in the powder flow rate acquisition unit 61a is read out from the powder The powder flow rate acquisition unit 61a is commanded to be sent to the flow rate control unit 62a (S805a).

FI_A can be defined by the following expression, for example.
FI_A = specified amount (1−kx) (Equation 1) k is a proportionality constant and x is time.
For example, when the powder flow rate is represented by the blowing speed (t / h) (t is the ton of weight unit), the blowing speed that can be set is set to 0 to 100 t / h. When the blowing speed increase / decrease capability of the powder supply apparatus is ± 10 t / h per minute, the blowing speed increase / decrease rate is ± 10% / min (= ± 0.1 / min). Therefore, the proportional constant is set to k = 0.1 / min, and the unit of x is set to minute (min).

Next, the powder flow rate acquisition unit 61a is instructed to calculate and transmit FI_B to the powder flow rate acquisition unit 61b of the powder supply apparatus B (S806a). The process of calculating and transmitting this FI_B corresponds to the process of transmitting a parallel blowing start command signal to the powder supply apparatus B.
FI_B transmitted at this time is defined by the following equation 2.
FI_B = specified amount-FI_A = specified amount-specified amount (1-kx) = kx x specified amount (Equation 2)
When the powder flow rate acquisition unit 61b of the control unit 5b receives this FI_B, the blowing from the blowing tank 1b of the powder supply device B is started. This flow will be described later.

During parallel blowing, if WI_A is larger than a predetermined lower limit L2 (L2 <L1) (NO in S807a), parallel blowing is continued, but if WI_A is equal to or less than L2 (YES in S807a), In order to stop the blowing from the blowing tank 1a of the powder supply apparatus A, the valve opening / closing control unit 64a is instructed to close the pressurization control valve 2a and the lower valve 7a, and monitoring of WI_A is stopped (S808a). ). Thereby, the blowing from the powder supply apparatus A stops. And a blowing stop signal is transmitted with respect to the tank switching control part 63b of the powder supply apparatus B (S809a).
While the operation is stopped, the blowing tank 1a is filled with powder from a storage tank (not shown) until the next operation command (that is, reception of FI_A (Equation 4) from the powder supply apparatus B in S810a). I will wait.

For convenience of explanation, the description of the processing of the tank switching control unit 63a is temporarily stopped here, and the processing of the tank switching control unit 63b is described.
When the tank switching control unit 63b detects that the powder flow rate acquisition unit 61b has received FI_B (Equation 2) from the powder supply device A during standby of the powder supply device B (YES in S801b), valve opening / closing control is performed. A command to open the pressurization control valve 2b and the lower valve 7b is issued to the unit 64b (S802b), and monitoring of the value of the weighing instrument 4b (hereinafter referred to as WI_B) is started (S803b). That is, monitoring of the weight of the powder remaining in the blowing tank 1b is started.

  Next, a command to acquire FI_B (Equation 2) received in S801b from the powder flow rate acquisition unit 61b is issued to the powder flow rate control unit 62b, and parallel blowing is started (S804b). After continuing the parallel blowing for a while, a blow stop signal is received from the powder supply device A, and when it is detected that the powder supply device A has stopped blowing (YES in S805b), the powder flow rate acquisition unit 61b On the other hand, a command to set FI_B to a specified amount is issued, and blowing is continued (S806b). Therefore, from here, it shifts to the single blowing by the powder supply apparatus B. Here, the reason why FI_B is set to a specified amount is that it is necessary to blow a specified amount of powder by the powder supply apparatus B alone.

After the start of single blowing from the blowing tank 1b, while WI_B is larger than the predetermined value (L1) (NO in S807b), blowing is continued as it is.
Then, when WI_B becomes L1 or less (YES in S807b), the flow shifts to parallel blowing with the blowing tank 1a.
Here, the parallel blowing means that the blowing amount from the blowing tank 1a is gradually increased while the blowing amount from the blowing tank 1b is gradually reduced, and the total blowing amount of both is a specified amount (a constant amount). It is to control to become.

Therefore, the pre-defined function stored in the powder flow rate acquisition unit 61b with a function (Formula 3 to be described later) that gradually decreases FI_B at the time of parallel blowing is read out from the powder. The powder flow rate acquisition unit 61b is instructed to send to the flow rate control unit 62b (S808b).
FI_B can be defined by the following equation, for example, similarly to Equation 1 described above.
FI_B = specified amount (1−kx) (Expression 3) k is a proportionality constant, and x is time.
The proportionality constant is set to k = 0.1 / min, and the unit of x is set to minute (min).

Next, the powder flow rate acquisition unit 61b is instructed to calculate and transmit FI_A to the powder flow rate acquisition unit 61a of the powder supply apparatus A (S809b). The FI_A is defined by the following equation 4.
FI_A = specified amount-FI_B = specified amount-specified amount (1-kx) = kx x specified amount (Equation 4)
When the powder flow rate acquisition unit 61a of the control unit 5a receives this FI_A, the powder supply device A starts to blow from the blowing tank 1a and enters the parallel blowing state. This flow will be described later.

While WI_B is larger than the predetermined lower limit L2 during parallel blowing (NO in S810b), the parallel blowing is continued, but when WI_B becomes L2 or less (YES in S810b), the powder supply device In order to stop the injection of B from the injection tank 1b, the valve opening / closing control unit 64b is instructed to close the pressurization control valve 2b and the lower valve 7b, and monitoring of WI_B is stopped (S811b). Thereby, the blowing from the powder supply apparatus B stops. And a blowing stop signal is transmitted with respect to the tank switching control part 63a of the powder supply apparatus A (S812b).
While the operation of the powder supply apparatus B is stopped, the blowing tank 1b is filled with powder, and the apparatus waits until the next operation command (ie, S801b) is issued.

The processing of the tank switching control unit 63a will be described again. In S810a of FIG.
When the tank switching control unit 63a detects that the powder flow rate acquisition unit 61a has received FI_A (Equation 4) from the powder supply device B (YES in S810a), the pressurization control valve 2a with respect to the valve opening / closing control unit 64a. In addition, a command to open the lower valve 7a is issued (S811a), and monitoring of WI_A is started (S812a). That is, monitoring of the weight of the powder remaining in the blowing tank 1a is started.

Next, a command to acquire FI_A (Equation 4) received in S810a from the powder flow rate acquisition unit 61a is issued to the powder flow rate control unit 62a, and parallel blowing is started (S813a). After continuing the parallel blowing for a while, a blow stop signal is received from the powder supply device B, and when it is detected that the powder supply device B has stopped blowing (YES in S814a), the powder flow rate acquisition unit 61a On the other hand, a command to set FI_A to a specified amount is issued, and blowing is continued (S803a). Therefore, after that, the powder supply device A shifts to single blowing. The reason why FI_A is set to a prescribed amount here is that it is necessary to blow a prescribed amount of powder by the powder supply apparatus A alone.
By repeating the above processing, it is possible to control so that the sum of the set value of the powder supply apparatus A and the set value of the powder supply apparatus B becomes a specified amount.

The case where two powder supply apparatuses are connected in parallel has been described above as an example, but the present invention can be similarly applied to the case where three or more powder supply apparatuses are connected.
For example, when the third powder supply apparatus C is used, the processing flow of the tank switching control unit 63C (not shown) is the same as the processing of the tank switching control unit 63b in FIG.
That is, the flow in which step numbers “S801b to S812b” in FIG. 8 are replaced with “S801C to S812C” is added in one column, the subscripts “b, B” are respectively replaced with “c, C”, and S801C is further replaced. S805C may be replaced with “Don't blow powder supply device B?” To “Is FI_C received from powder supply device B?”.
In this case, S810a is transmitted to “Is FI_A received from powder supply apparatus C?”, S814a is transmitted to “Stop blowing powder supply apparatus C?”, And S809b is transmitted to “FI_C to powder supply apparatus C”. S812b needs to be changed to "Transmission stop signal to powder supply device C".

By doing in this way, the switching order of the powder supply apparatuses A, B, and C is as follows.
(1) Single blow of powder supply apparatus A (2) Parallel blow of powder supply apparatus A and powder supply apparatus B (3) Single blow of powder supply apparatus B (4) Powder supply apparatus B And parallel blowing of powder supply device C (5) Single blowing of powder supply device C (6) Parallel blowing of powder supply device C and powder supply device A → Return to (1).

FIG. 9 is an example of a flowchart showing a flow of processing performed by the valve opening / closing control unit 64. This process starts when a command is received from the tank switching control unit 63.
First, the pressurization control valve 2 and the lower valve 7 are opened by a command from the tank switching control unit 63 (S901).
Next, a set value (FI) is acquired from the powder flow rate acquisition unit 61 (S902). With reference to the later-described lookup tables (FIGS. 10 and 11) provided in the valve opening / closing control unit 64 using the acquired FI as a key, the corresponding variable valve opening (%) and carrier gas amount control valve opening (% ) Is acquired (S903).

Next, the opening degree of each valve is set according to the obtained variable valve opening degree and carrier gas amount control valve opening degree (S904). When there is no blow stop command from the tank switching control unit 63 (NO in S905), the next set value is acquired (S902), and the same processing is repeated thereafter.
On the other hand, when there is a blow stop command from the tank switching control unit 63 (YES in S905), the pressurization control valve 2 and the lower valve 7 are closed (S906), and the process is terminated.

FIG. 10 shows a look-up table 10 that defines the relationship between the set value (FI) and the variable valve opening (%). In FIG. 10, the increment of the FI value may be appropriately set according to the performance of the variable valve.
FIG. 11 shows a look-up table 11 that defines the relationship between the set value (FI) and the carrier gas amount control valve opening (%). Note that FIC (Nm ² / h) is a value indicating the amount of carrier gas per unit time corresponding to the set value (FI), and is shown for reference.

[Second Embodiment]
In the first embodiment, as shown in FIG. 4, the control units 5a and 5b are provided independently for each powder supply apparatus, but the control unit 5 is common in the second embodiment, The only difference is that it is provided only (not shown). Since FIG. 6, FIG. 7 and FIGS. 9 to 11 are the same, description thereof is omitted.
Note that the CPU 51 of the control unit 5 is required to be capable of multitask processing, and controls the powder supply device A and the powder supply device B simultaneously and in parallel.

FIG. 12 is an example of a flowchart showing a flow of processing performed by the tank switching control unit 63 when simultaneous control is performed by one control unit 5. This process starts when the operator depresses a blow start button (not shown) after filling the blow tank 1 with powder.
First, the case where the blowing is started from the blowing tank 1a of the powder supply apparatus A will be described as an example.
In the flow of FIG. 12, steps S1002a to S1011a and S1002b to S1010b are processed in parallel, but for convenience of explanation, steps S1002a to S1011a will be explained first, and then S1002b to S1010b will be explained. I will do it.

First, monitoring of the value of the weighing instrument 4a (WI_A) and the value of the weighing instrument 4b (WI_B) is started (S1001). This is because there is only one control unit 5 and therefore it is necessary to monitor the values (WI) of both weighing units 4.
Next, the valve opening / closing control unit 64 is instructed to open the pressurization control valve 2a and the lower valve 7a (S1002a), and a powder flow rate setting unit 61 is referred to as a powder flow rate setting value (hereinafter referred to as FI_A). .) Is set to a prescribed amount, and blowing from the blowing tank 1a is started (S1003a).

After the start of blowing from the blowing tank 1a, while WI_A is larger than the predetermined value (L1) (NO in S1004a), blowing is continued as it is (that is, without changing the set value).
Then, when WI_A becomes L1 or less (YES in S1004a), the flow shifts to parallel blowing with the blowing tank 1b.
Therefore, what is previously defined by a function (formula 1 described above) that gradually decreases FI_A during parallel blowing from the specified amount and stored in the powder flow rate acquisition unit 61 is read out from the powder. The powder flow rate acquisition unit 61 is commanded to be sent to the flow rate control unit 62 (S1005a).
In parallel blowing, while gradually reducing the amount of blowing from the blowing tank 1a, the amount of blowing from the blowing tank 1b is gradually increased so that the total amount of both blowing becomes a specified amount (a constant amount). Is to control. In the parallel blowing state, blowing from the blowing tank 1b of the powder supply apparatus B is started. This flow will be described later.

During parallel blowing, while WI_A is greater than a predetermined lower limit L2 (L2 <L1) (NO in S1006a), parallel blowing is continued, but when WI_A becomes L2 or less (YES in S1006a) Then, in order to stop the blowing from the blowing tank 1a of the powder supply device A, the valve opening / closing control unit 64 is instructed to close the pressurization control valve 2a and the lower valve 7a (S1007a). Thereby, the blowing from the powder supply apparatus A stops.
While the operation is stopped, the blowing tank 1a is filled with powder from a storage tank (not shown), and the next operation command (ie, when the value WI_B of the weighing device of the powder supply device B becomes L1 or less in S1008a). ) Wait until there is.

Next, when it is detected that WI_B has become L1 or less (YES in S1008a), a command to open the pressurization control valve 2a and the lower valve 7a is issued to the valve opening / closing control unit 64 (S1009a), and the powder A command to acquire FI_A (Equation 4) from the powder flow rate acquisition unit 61 is issued to the flow rate control unit 62, and parallel blowing is started (S1010a).
When it is detected that WI_B of the powder supply apparatus B has become L2 or less after continuing the parallel blowing for a while (YES in S1011a), a command to set FI_A to a specified amount to the powder flow rate acquisition unit 61 And blowing is continued (S1003a). Therefore, after that, the powder supply device A shifts to single blowing. The reason why FI_A is set to a prescribed amount here is that it is necessary to blow a prescribed amount of powder by the powder supply apparatus A alone.
By repeating the above processing, it is possible to control so that the sum of the set value of the powder supply apparatus A and the set value of the powder supply apparatus B becomes a specified amount.

Next, in S1002b to S1010b, the process for the powder supply apparatus B is basically the same as the process for the powder supply apparatus A.
That is, S1002b to S1010b correspond exactly to S1008a to S1011a and S1003a to S1007a. In the processing contents of S1002b to S1010b, if A is read as B, b as a, and B as A, S1008a The processing contents of S1011a and S1003a to S1007a are exactly the same. Therefore, the subsequent description is omitted.
The case where two powder supply apparatuses are connected in parallel has been described above as an example, but the present invention can be similarly applied to the case where three or more powder supply apparatuses are connected.

  This is the end of the description of the embodiment. In the first embodiment of the present invention, when the remaining amount of the powder in the blowing tank 1a of the powder supply apparatus A in operation becomes L1 or less, the powder The process in which the powder flow rate acquisition unit 61a of the supply apparatus A calculates FI_B (Equation 2) and transmits it to the powder supply apparatus B transmits a parallel blowing start command signal to the powder supply apparatus B. Although it corresponds to processing, the present invention is not limited to this.

For example, the above formulas 1 and 4 are stored in advance in the powder flow rate acquisition unit 61a, and the above formulas 2 and 3 are stored in the powder flow rate acquisition unit 61b, respectively. It is also possible to simply send a command trigger signal.
In the above embodiment, the variable valve opening and the carrier gas amount control valve opening are set based on the powder flow rate setting value (FI). However, the present invention is not limited to this. For example, the measured value of the powder flow rate may be used instead of the set value (FI), and the valve opening may be determined with reference to the look-up tables 10 and 11 in FIGS.
Furthermore, rather than relying on a lookup table to set the valve opening, the valve opening is defined as a function of a set value or an actual value, and the valve opening obtained by calculation from the acquired set value or the actual value is calculated. It can also be used.
Examples of powders other than pulverized coal include quick lime, dephosphorizing agents (for example, powders mixed with lime, iron oxide, meteorite, etc.), desulfurizing agents (iron oxide or zinc oxide particles) ) Etc.
The specific configuration, processing contents, data configuration, and the like of the powder supply apparatus are not limited to those described in the embodiment. Modifications can be made without departing from the spirit of the present invention.

1: blow tank, 2: pressurization control valve, 3: variable valve, 4: weighing device, 5: control unit, 6: powder transfer piping, 7: lower valve, 8: powder flow meter, 9: transfer gas Quantity control valve, 10: Look-up table, 11: Look-up table

Claims (8)

A blowing tank filled with powder inside, a weigher for detecting the weight of the powder in the blowing tank, a powder conveying pipe connected to a discharge port provided near the lower part of the blowing tank, A variable valve provided on the downstream side of the discharge port and capable of adjusting an amount of powder discharged from the discharge port by an opening of a valve; and a gas pressurized into the blowing tank is introduced, and the blowing A pressure control valve that adjusts the pressure of a pressurized gas for discharging the powder in the blowing tank from the discharge port according to the pressure difference in the tank and the pressure in the powder transfer pipe; and the powder transfer pipe A carrier gas amount control valve for controlling the amount of the carrier gas when introducing a carrier gas for conveying the powder into the powder, and a powder for measuring the flow rate of the powder conveyed in the powder carrier pipe The powder conveyance by controlling the flow rate measuring means and the opening degree of each valve A plurality of powder supply devices, each having a control means for controlling the flow rate of the powder conveyed in the pipe, are connected in parallel, and each powder supply device is switched or simultaneously operated while a constant amount of powder is supplied. A powder parallel blowing system for conveying and supplying a body,
The control means controls the opening and closing of the valves based on the opening degree of the valve corresponding to a preset powder flow rate setting value, and the measured powder flow rate value measured by the powder flow rate measurement means is Controlling the pressurization control valve to approach the powder flow rate setting value,
When the weight of the powder in the blowing tank of one of the plurality of powder supply apparatuses in operation is equal to or less than a predetermined value (L1), the powder supply apparatus The control unit transmits the powder flow rate setting value of the powder to be conveyed by the other powder supply device to the other powder supply device, and receives the powder flow rate setting value. The control means of the apparatus starts conveying and supplying the powder, and controls the flow rate of the powder based on the received powder flow rate setting value,
A powder parallel blowing system, wherein the total of the powder flow rate setting value of the one powder supply device and the powder flow rate setting value of the other powder supply device is controlled to be the constant amount. . A blowing tank filled with powder inside, a weigher for detecting the weight of the powder in the blowing tank, a powder conveying pipe connected to a discharge port provided near the lower part of the blowing tank, A variable valve provided on the downstream side of the discharge port and capable of adjusting an amount of powder discharged from the discharge port by an opening of a valve; and a gas pressurized into the blowing tank is introduced, and the blowing A pressure control valve that adjusts the pressure of a pressurized gas for discharging the powder in the blowing tank from the discharge port according to the pressure difference in the tank and the pressure in the powder transfer pipe; and the powder transfer pipe A carrier gas amount control valve for controlling the amount of the carrier gas when introducing a carrier gas for conveying the powder into the powder, and a powder for measuring the flow rate of the powder conveyed in the powder carrier pipe A plurality of powder supply devices equipped with flow rate measuring means are connected in parallel, and Each powder supply apparatus comprising: one control means for controlling the flow rate of the powder conveyed through each powder conveyance pipe by controlling the opening of each valve of each powder supply apparatus. A powder parallel blowing system that continuously feeds a certain amount of powder while switching or operating simultaneously,
The control means controls the opening and closing of the valves based on the opening degree of the valve corresponding to a preset powder flow rate setting value, and the measured powder flow rate value measured by the powder flow rate measurement means is Controlling the pressurization control valve to approach the powder flow rate setting value,
When the weight of the powder in the blowing tank of one of the plurality of powder supply apparatuses in operation is equal to or less than a predetermined value (L1), the other powder supply apparatuses Setting the powder flow rate setting value of the powder to be conveyed by the other powder supply device, and starting the conveyance of the powder from the other powder supply device,
A powder parallel blowing system, wherein the total of the powder flow rate setting value of the one powder supply device and the powder flow rate setting value of the other powder supply device is controlled to be the constant amount. . When the weight of the powder in the blowing tank of one of the plurality of powder supply apparatuses in operation is equal to or less than a predetermined value (L1), the powder supply apparatus The control means transmits a parallel blowing start command to another powder supply apparatus, and the control means of the other powder control apparatus that has received the parallel blowing start command starts conveying and supplying the powder. Along with controlling the powder flow rate based on the preset powder flow rate setting value at the time of parallel blowing,
2. The control according to claim 1, wherein the total of the powder flow rate setting value of the one powder supply device and the powder flow rate setting value of the other powder supply device is controlled to be the constant amount. Powder parallel blowing system.   Furthermore, a lower valve is provided between the discharge port and the variable valve, and the pressure is increased when the weight of the powder in the blowing tank becomes less than a value (L2) smaller than the predetermined value (L1). The powder parallel blowing system according to any one of claims 1 to 3, wherein the control valve and the lower valve are closed to stop the discharge of the powder into the powder conveying pipe.   Further, a lower valve is provided between the discharge port and the variable valve, and the pressurization control valve is disposed after a predetermined time has elapsed since the weight of the powder in the blowing tank becomes equal to or less than the predetermined value (L1). 4. The powder parallel blowing system according to claim 1, wherein the discharge of the powder into the powder conveyance pipe is stopped by closing the lower valve. 5.   The control means controls opening and closing of each valve based on an opening degree of a valve corresponding to the measured powder flow rate value instead of the preset powder flow rate set value. The powder parallel blowing system according to any one of 1 to 3. A lookup table associating the powder flow rate setting value with the opening of the variable valve and the opening of the carrier gas amount control valve;
The control means refers to the lookup table, acquires the opening of the variable valve and the opening of the carrier gas amount control valve corresponding to the powder flow rate setting value, and acquires the opening of each acquired valve The powder parallel blowing system according to any one of claims 1 to 4, wherein the opening and closing of each valve is controlled based on the above. A blowing tank filled with powder inside, a weigher for detecting the weight of the powder in the blowing tank, a powder conveying pipe connected to a discharge port provided near the lower part of the blowing tank, A variable valve provided on the downstream side of the discharge port and capable of adjusting an amount of powder discharged from the discharge port by an opening of a valve; and a gas pressurized into the blowing tank is introduced, and the blowing A pressure control valve that adjusts the pressure of a pressurized gas for discharging the powder in the blowing tank from the discharge port according to the pressure difference in the tank and the pressure in the powder transfer pipe; and the powder transfer pipe A carrier gas amount control valve for controlling the amount of the carrier gas when introducing a carrier gas for conveying the powder into the powder, and a powder for measuring the flow rate of the powder conveyed in the powder carrier pipe The powder conveyance by controlling the flow rate measuring means and the opening degree of each valve A plurality of powder supply devices, each having a control means for controlling the flow rate of the powder conveyed in the pipe, are connected in parallel, and each powder supply device is switched or simultaneously operated while a constant amount of powder is supplied. A powder parallel blowing method for conveying and supplying a body,
The control means controls the opening and closing of the valves based on the opening degree of the valve corresponding to a preset powder flow rate setting value, and the powder flow rate measurement value measured by the powder flow rate measurement means is Controlling the pressurization control valve to approach the powder flow rate setting value; and
When the weight of the powder in the blowing tank of one of the plurality of powder supply apparatuses in operation is equal to or less than a predetermined value (L1), the powder supply apparatus A step of transmitting a powder flow rate setting value of the powder to be conveyed by the other powder supply device to the other powder supply device; and the other powder having received the powder flow rate setting value. A control unit of the body control device includes a step of starting conveyance of powder and controlling the flow rate of the powder based on the received powder flow rate setting value;
Controlling so that the sum of the powder flow rate setting value of the one powder supply device and the powder flow rate setting value of the other powder supply device becomes the constant amount. .