JP3292257B2 - Granular material transfer control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method for controlling the transfer of powder and granular material such as pulverized coal to a high pressure supply destination such as a blast furnace.

[0002]

2. Description of the Related Art As a conventional method for controlling the transfer of powder and granular material, Japanese Patent Application Laid-Open No. 58-74426 (hereinafter referred to as a first conventional example) and Japanese Patent Application Laid-Open No. 31640/1994, which have been proposed by the present applicant, have been proposed.
No. 5 (hereinafter referred to as a second conventional example). In a first prior art example, in a method for distributing and transporting powder and granules provided with an aerator at a bottom portion of a pressure vessel and supplying unnecessary powder and granules by a pressurized gas into a plurality of transport pipes through a plurality of discharge nozzles, By individually changing the booster flow rate flowing through the booster pipe connected to each transport pipe while keeping the internal pressure constant, the amount of the granular material cut out from the container to each transport pipe per unit time can be reduced. A method for adjusting the cut-out amount of a granular material in which the cut-out amount is adjusted with high responsiveness by adjusting the amount is disclosed.

In the second prior art, pulverized coal pulverized by a pulverized coal mill is cut out while being stored in a pulverized coal buffer tank, and the pulverized coal is blown into a blast furnace tuyere while controlling the transport amount by the booster flow rate. In the control method
While detecting the change information of the bulk specific gravity of the pulverized coal from the load fluctuation amount of the coal mill, the time delay until the pulverized coal having the changed bulk specific gravity reaches the pressure vessel is also determined by the remaining amount of the pulverized coal buffer tank. By controlling the internal pressure of the pressure vessel at the time of blowing the pulverized coal of which the bulk specific gravity has changed based on the estimated delay time, the pulverized coal injection into the blast furnace tuyere with high accuracy. A pulverized coal injection amount control method that can be stably controlled is disclosed.

[0004]

However, in the first and second conventional examples, the upper tank for storing the powder and the granular material is supplied from the upper tank, When the lower tank that sends out the granules to the transport pipe is connected in series to form a powder supply mechanism, and the amount of carrier gas supplied to the transport pipe is controlled based on the change in the weight of the lower tank, the target It is necessary to add the estimated amount as a correction term to the control amount in order to cope with the weight change due to the influence of the inertia force caused by the pressure change of the upper tank and the lower tank, the gas pressurization amount change to the lower tank, etc. There is an unsolved problem that the control accuracy of the granular material conveyance amount is reduced. In particular, when the amount of the granular material remaining in the lower tank is reduced, and when the granular material is charged into the lower tank from the upper tank, the change in weight of the lower tank is not proportional to the cutout amount of the granular material. Therefore, it cannot be used as the actual value of the cut-out amount, and when this granular material is charged, the change in the weight of the lower tank immediately before it has to be maintained and this must be used as the actual value, for example, pulverized coal blowing into the blast furnace. When considering the injection control, there is an unsolved problem that the amount of pulverized coal supplied to the pulverized coal injection burner via the lower tank and the transport pipe changes due to disturbance due to pressure fluctuations in the blast furnace and the like.

[0005] In order to solve this unsolved problem, as described in JP-A-61-153526,
Powder flow meters were installed on all transport pipes from the transport tank to each supply destination, and the flow rate of the powder transported through the transport pipe was directly measured to calculate the absolute mass of the powder. It has been proposed to control the amount of carrier gas on the basis of
According to this conventional example, since the powder flow meters are installed in all the transport pipes, a large installation space is required and the equipment cost is increased. There is also an unsolved problem that it is not always possible to control the transport amount of the granular material with high accuracy because the surface and maintenance are inferior to the load cell as the load sensor for detecting the weight of the lower tank in terms of weight.

Accordingly, the present invention has been made in view of the unsolved problem of the above-mentioned conventional example. Even if there is a pressure fluctuation of the high pressure supply destination when the powdery material is charged from the upper tank to the lower tank, the present invention is not limited to this. It is an object of the present invention to provide a method for controlling the transfer of a granular material capable of coping with the problem.

[0007]

In order to achieve the above object, a method for controlling the transfer of a granular material according to the present invention comprises an upper tank and a lower tank for storing granular materials connected in series, and a lower tank. In the method of controlling the transfer of the granular material in which the granular material in the container is gas-transported to the supply destination container by the transport gas, when the introduction of the granular material from the upper tank to the lower tank is stopped, the lower tank is normally By controlling the internal pressure of the lower tank based on the detected value of the change in weight, the amount of the granular material transported is controlled, and when the granular material is charged from the upper tank to the lower tank, the internal pressure of the lower tank, the internal pressure of the supply destination container and It is characterized in that the amount of the transported powder is controlled by controlling the amount of the transported gas so that the differential pressure of the powder becomes constant.

[0008]

According to the present invention, during normal times when there is no charging of the granular material from the upper tank into the lower tank, the transport of the granular material to the target container based on the detected value of the change in weight of the lower tank is performed. Calculates the amount and feeds back the lower tank internal pressure based on the calculated amount of transported granular material, thereby performing high-precision gas transport of the granular material. When the granular material stored in the lower tank is put into the lower tank, the change in weight of the lower tank is not proportional to the amount of the granular material cut out, so the differential pressure between the lower tank internal pressure and the internal pressure of the supply destination container is constant. By controlling the amount of carrier gas so as to satisfy the above condition, even when the internal pressure fluctuates in the supply destination container, a constant supply of the granular material is ensured.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment in which a pulverized material conveying device to which the present invention can be applied is applied to a pulverized coal injection system into a blast furnace. A plurality of tuyeres 2 for blowing pulverized coal are formed. A blowpipe 3 is connected to the tuyeres 2 and a pulverized coal blowing burner 4 is connected thereto. The blast furnace 1 is provided with a pressure sensor 5 for detecting its internal pressure.

The pulverized coal is supplied to the blast furnace 1 from the pulverized coal supply device 10 at a controlled flow rate. The pulverized coal supply device 10 is used for cutting pulverized coal having a service tank 11 as an upper tank to which pulverized coal is supplied and stored, and which is connected in series below the service tank 11 and has an aerator on the lower surface side. An injection tank 12 as a lower tank of the blast furnace 1 and a pulverized coal cut from the injection tank 12
Transport pipe 13 for transporting the transport gas connected to the middle of the transport pipe 13
, Service tank 11 and injection tank 12
And a pressurized gas supply pipe 15 for supplying pressurized nitrogen (N ₂ ) as a pressurized gas to the aerator.

In the service tank 11, pulverized coal conveyed from, for example, a pulverized coal pulverizing mill (not shown) is supplied and stored via an electromagnetic opening / closing valve 11a at the upper end side, and the internal pressure of the injection tank 12 is increased. Solenoid valve 1 with pulverized coal stored at the same pressure
By opening 1b, it is charged into the injection tank 12 via the communication pipe 11c formed of a flexible pipe. A load sensor 16 such as a load cell for detecting the weight of the service tank 11 and a pressure sensor 17 for detecting the internal pressure are attached to the service tank 11, and an electromagnetic on-off valve 11d for discharging the tank internal pressure to the atmospheric pressure and a throttle 11 are provided.
e is connected to an exhaust pipe 11f.

In the injection tank 12, the amount of pulverized coal cut out to the transport pipe 14 is determined according to the internal pressure of the pressurized gas supplied from the pressurized gas supply pipe 15, and the amount of pulverized coal cut out is transported. It is also changed by the amount of carrier gas from the carrier gas supply pipe 14 connected in the middle of the pipe 14. The injection tank 12 is also provided with a load sensor 18 such as a load cell for detecting its weight and a pressure sensor 19 for detecting an internal pressure.

A flow meter 20 for detecting the flow rate of the carrier gas and a flow control valve 21 for controlling the flow rate of the carrier gas are disposed in the carrier gas supply pipe 14 so that the flow meter 20 is located on the upstream side. The flow control valve 2 is controlled by a control device 30 described later.
By controlling 1, the flow rate of the carrier gas is adjusted. The pressurized gas supply pipe 15 is provided with pressure control valves 23 and 24 on the inlet sides of the service tank 11 and the injection tank 12, respectively.

The solenoid valves 11a, 11b, 11d of the service tank 11, the flow control valve 21 of the carrier gas supply pipe 14, and the pressure control valves 23, 2 of the pressurized gas supply pipe 15 are provided.
4 is controlled by the control device 30. This control device 3
0 is a pulverized coal injection amount setting unit 31 for setting the total amount of pulverized coal injection into the blast furnace 1 by an operator, as shown in FIG.
And a divider 32 for calculating the blowing amount for each tuyere by dividing the set value of the blowing amount setting device 31 by the number of tuyeres, and the blowing amount W for each tuyere calculated by the divider 32. The tuyere-pulverized-coal-pulverized-coal-pulverized-coal-pulverized-coal amount setting device 33 includes a tuyere-injection amount setting unit 34 for each tuyere and a tuyere-injection amount W for each tuyere output from the injection amount setting unit 34. An injection tank internal pressure control unit 35 for controlling the internal pressure of the injection tank 12 based on the same, a carrier gas flow control unit 36 for similarly controlling a carrier gas flow rate based on the blowing amount W for each tuyere, and an injection of the service tank 11. A pulverized coal input control unit 37 for controlling pulverized coal input to the tank 12 is provided.

Injection tank internal pressure control unit 35
A function generator 41 which receives the pulverized coal injection amount W for each tuyere set by the pulverized coal injection amount setting device 33 and outputs a tank internal pressure set value SV ′ of the injection tank 12 based on the input; A weight corrector 42 that corrects the load detection value of the load sensor 17 that detects the weight of the injection tank 12, and a moving averager that performs a moving average process on the corrected load detection value corrected by the weight corrector 42 to remove noise components. 43, a differentiator 44 for differentiating the moving average value output from the moving averager 43 to calculate an injection tank weight change amount, and an injection tank based on the injection tank weight change amount output from the differentiator 44. calculates a pulverized coal blown amount actual value extracted from the 12, calculate the deviation α between the blowing amount W _T of the actual value and the pulverized coal blown amount setter 31 The internal pressure set value S of the injection tank 12 is obtained by adding the weight controller 45 to be output, the injection tank internal pressure SV ′ output from the function generator 41 described above, and the deviation α output from the weight controller 45.
The internal pressure set value calculator 46 for calculating V, and the internal pressure set value SV output from the internal pressure set value calculator 46 when the input state signal from the input state detector 50 described later is changed from the OFF state to the ON state. Hold circuit 47
Then, the hold value SV _H of the hold circuit 47 is supplied to one input side, and the internal pressure set value SV is supplied to the other input side as it is, and the input state signal ST from the pulverized coal input control unit 37 is turned off. Internal pressure set value S when in the state
V, and a selection circuit 48 for selecting the hold value SV _H when the closing state signal ST is in the on state. The selection value SV or SV _H output from the selection circuit 48 is input and the injection tank An internal pressure detection value of the pressure sensor 18 provided in the apparatus 12 is input, and a pressure controller 47 for controlling the pressure control valve 24 of the pressurized gas supply pipe 15 based on the input value is provided. Here, the function generator 41
Until the pulverized coal blown amount W reaches the set value W _S which is preset tank pressure set value SV 'becomes a constant value, the tank in proportion to the increase of the pulverized coal blown amount W exceeds the set value W _S The internal pressure set value SV 'is set to a line function that increases.

The carrier gas control unit 36 receives the pulverized coal blowing amount W for each tuyere set by the pulverized coal blowing amount setting unit 33, and calculates the carried gas amount set value _QFU based on only this. a normal carrier gas amount calculating unit 51, pulverized coal blown amount W of each tuyere, the tank internal pressure detected value P _B of the injection tank 12 from the high furnace pressure detection value P _C and the pressure sensor 19 from the pressure sensor 5 enter is a-on carrier gas calculator 52 for calculating a carrier gas amount set value Q _FF which a differential pressure ΔP between the furnace pressure detection value P _C and the tank internal pressure detection value P _B is constant,
Normal-time transfer gas calculator 51 and loading-time transfer gas calculator 5
The carrier gas amounts Q _FU and Q _FF calculated in step 2 are input, and the carrier gas amount Q _FU is selected when the input state signal ST of the pulverized coal input control unit 37 is off, and the input state signal ST is turned on. A selection circuit 53 for selecting the carrier gas amount Q _FF in the state, and a carrier gas amount Q selected by the selection circuit 53;
_{The FU} or Q _FF is input, and the flow rate detection value of the flow meter 20 provided in the carrier gas supply pipe 14 is input, and the flow controller 54 that controls the flow control valve 21 of the carrier gas supply pipe 14 based on these is input. And

The pulverized coal input controller 37 detects the weight detected by the load sensor 16 of the service tank 11 and the service tank 1
The microcomputer 60 to which the internal pressure detection value of the pressure sensor 17, the weight detection value of the load sensor 18 of the injection tank 12, and the internal pressure detection value of the pressure sensor 19 of the injection tank 12 are input, and an output side of the microcomputer 60. Connected service tank 1
Drive circuits 61, 62, and 63 for opening and closing one electromagnetic on-off valve 11a, 11b, and 11d;
Is composed of a pressure regulator gauge 64 pressure sensing value P _A of the pressure sensor 17 is input to drive the pressure control valve 23 of the pressurized gas supply pipe 15 for a predetermined arithmetic processing based on the input of a microcomputer 60 To control the charging of pulverized coal to the service tank 11 and the charging of pulverized coal from the service tank 11 to the injection tank 12.

Here, an example of the processing procedure of the microcomputer 60 will be described with reference to FIG. First, step S
1, the weight measurement value L _L of the load sensor 18 of the injection tank 12 reads, then proceeds to the weight detected value L _L is determined whether or not equal to or less than the first setting value S1 which is set in advance in step S2 , L _L > S1,
Returning to step S1, when L _L ≦ S1, the process proceeds to step S3.

In this step S3, the service tank 1
1 and reads the pressure detection value P _A and P _B of the pressure sensor 17 and 19 of the injection tank 12, and then determines whether migration to both pressure sensing value P _A and P _B is equal to step S4, P _A when ≠ a P _B, the process proceeds to step S5, returns the pressure detection value P _a from the delivery to the pressure adjusting meter 63 as a pressure set value to the step S3, P _a
= When a P _B, the process proceeds to step S6.

[0020] In step S6, reads the weight detection value L _L of the load sensor 18 of the injection tank 12, and then proceeds to the smaller first set value S1, which weight detection value L _L is preset in the step S7 the It is determined whether or not the value has become equal to or less than the set value S2 of 2. If L _L > S2, the process returns to step S4, and if L _L ≦ S2, the process proceeds to step S8.

In step S8, the service tank 1
1, the opening operation signal for the lower opening / closing valve 11b is turned on.
The input state signal ST indicating that pulverized coal is being input from the injection tank 12 into the injection tank 12 is turned on, and then the process proceeds to step S10, where the set value for the pressure controller 64 for controlling the pressure on the service tank 11 is set to zero. To stop pressure control.

[0022] Next, the processing proceeds to step S11, reads the weight detection value L _U of the load sensor 16 of the service tank 11, and then proceeds to step S12, the lower limit of the weight detected value L _U service tank 11 is preset It is determined whether or not the weight setting value is equal to or less than S3. If L _U > S3, the process returns to step S11. If L _U ≦ S3, the process proceeds to step S13.

In step S13, the open operation signal for the lower opening / closing valve 11b of the service tank 11 is turned off.
After waiting for a predetermined period of time required for b to be in the closed state, the process proceeds to step S15, and the exhaust pipe 11f of the service tank 11 is
Of the opening operation signal for this open state to the electromagnetic on-off valve 11d is turned on, then the process proceeds to step S16, the pressure sensing value Nde reading the pressure detected value P _A of the pressure sensor 17 of the service tank 11 P _a is transferred after waiting until reduced to atmospheric pressure to step S17.

In step S17, the opening / closing signal for opening / closing the exhaust pressure opening / closing valve 11d of the service tank 11 is turned off, and the upper electromagnetic opening / closing valve 1d is opened.
An open operation signal for opening the pulverized coal is turned on for 1a, and then the process proceeds to step S18, where a pulverized coal pulverizer (not shown) is started, and pulverized coal pulverized by the pulverizer is removed. Bag filter and upper solenoid on-off valve 11a for gas transport
Into the service tank 11 via the.

Next, the process proceeds to step S19, where the detected weight value L _U of the load sensor 16 of the service tank 11 is read, and then proceeds to step S20, where the detected weight value L
_It is determined whether _U has reached the upper limit value L _UMAX , and L _U <L
_{If UMAX} , the process returns to step S19, and L _U ≧ L
_If it is _UMAX , the process shifts to step S21 to stop the pulverized coal pulverizer, then shifts to step S22, waits for a predetermined time, and shifts to step S23.

In this step S23, the opening operation signal for the upper electromagnetic opening / closing valve 11a of the service tank 11 is turned off. Then, the process goes to step S24 and waits for a predetermined time, then goes to step S25 to turn off the closing state signal ST. After returning to the state, the process returns to step S1, and the same processing as described above is repeated. Next, the operation of the above embodiment will be described with reference to a time chart shown in FIG.

At time t ₀ , all of the solenoid valves 11 a, 11 b, and 11 d of the service tank 11 are all closed, and the pulverized coal injection from the service tank 11 to the injection tank 12 is stopped. It is assumed that the input state signal ST of 37 is in the OFF state, a predetermined amount of pulverized coal is stored in the service tank 11, and a predetermined amount of pulverized coal is cut out from the injection tank 12 and transported. It is assumed that the carrier gas is supplied to the blast furnace tuyere 2 by the carrier gas supplied to the pipe 13.

In this state, the injection tank 1
The pressure control valve 24 of the pressurized gas supply pipe 15 is controlled by the injection tank internal pressure control unit 35 of the control device 30 based on the pulverized coal blowing amount W for each tuyere set by the blowing amount setting unit 34. . That is, the injection amount W is set by the function generator 41 of the injection tank internal pressure control unit 35.
The injection tank internal pressure P _B corresponding is set as a target value, which the feedback is based on the deviation between the actual cutting-out amount and the blowing amount setting value obtained by differentiating the weight measurement value L _L from load sensor 18 of the injection tank 12 Correction The internal pressure set value SV, which is a function of the amount of pulverized coal blown with respect to the blowing pressure of the blow pipe 3 of the blast furnace 1 and is higher by, for example, about ² to 3 kg / cm ² , is selected by the selection circuit 48 and the pressure controller 49, the pressure controller 49
In, controls the pressure control valve 24 interposed in the pressurized gas supply pipe 15 to the injection tank 12 based on the pressure detection value P _B of the pressure sensor 19 of the pressure set value SV and the injection tank 12.

As described above, the pressure control valve 24 is controlled to
Internal pressure P of injection tank 12 _BTo control
Thus, the amount of the carrier gas from the carrier gas supply pipe 14 is constant,
At the junction of the transport pipe 13 and the carrier gas supply pipe 14
Internal pressure P_DInjection is assumed to be constant
Tank internal pressure P_BAnd internal pressure P_DPressure difference ΔP (= P _B
−P_D) And the amount of pulverized coal injected are as shown in FIG.
In addition, as the differential pressure ΔP increases, the blowing amount increases in a parabolic manner.
And the injection tank internal pressure P_BIncrease
Thereby, the blowing amount can be increased.

At the same time, the amount of carrier gas in the carrier gas supply pipe 14 connected to the transport pipe 13 is controlled by the carrier gas controller 36 of the controller 30. At this time, since the pulverized coal injection from the service tank 11 to the injection tank 12 is stopped and the input state signal ST is in the OFF state, the pulverized coal is calculated by the selection circuit 53 of the transfer gas control unit 36 by the transfer gas calculator 51. that carrier gas amount Q _F only based on blowing amount W blow amount setting unit 34 each tuyere every set in is selected, this because is supplied to the flow rate adjusting meter 54, the carrier gas quantity at this flow rate adjusting meter 54 and controlling the flow rate control valve 21 based on the detected flow rate value of the flow meter 20 of Q _F and carrier gas supply pipe 14, whereby the transportation pipeline 13 transporting gas supply pipe 14
Of the internal pressure P _B of the injection tank 12 and the internal pressure P _{D at} the junction of the carrier gas supply pipe 14 of the transport pipe 13 by adjusting the internal pressure at the junction of
Can be set pulverized coal cutting amount according to P, the injection tank internal pressure P _B is constant, by increasing the carrier gas amount Q _F, the pressure difference ΔP to increase the confluence pressure It is possible to reduce the blowing amount by reducing the amount. Then, the pulverized coal cut out from the injection tank 12 by the transport gas is transported to each tuyere 2 of the blast furnace 1 through the transport pipe 13 and blown into the blast furnace 1.

As described above, the injection tank 12
By continuing the pulverized coal cut from the weight detection value L _L of the injection tank 12 is decreased as shown in FIG. 4 (b), the injection tank 1 at time t ₁
When 2 weight detection value L _L reaches the set weight S1, the processing of step S3~S5 in the processing of FIG. 3, the injection tank internal pressure P _A of the service tank 11 1
And raised to be equal to the second pressure P _B for holding a boosted state.

[0032] Then, at time t _2, when the weight detected value L _L of the injection tank 12 reaches the lower weight set value S2, the lower on-off valve 11b is controlled to the open state of the service tank 11 through the process of step S8 in FIG. 3 Then, the charging of the pulverized coal from the service tank 11 to the injection tank 12 is started, and the charging state signal ST is inverted from the off state to the on state.

According to the ON state of the input state signal ST, the hold circuit 47 of the lower internal pressure control unit 35 of the control device 30 holds the injection tank internal pressure set value SV immediately before the start of injection as shown in FIG. At the same time, when the hold circuit 47 is selected by the selection circuit 48, the set value of the pressure controller 49 is held at the value immediately before the start of injection, and the internal pressure of the injection tank 12 is controlled based on the change in weight of the injection tank 12. Interrupt.

On the other hand, in the carrier gas control unit 36,
When the signal ST is turned on, the selection circuit 53
The carrier gas computing unit 52 is selected, and the carrier gas computing unit 5
2, the injection amount W, the injection tank 1
Internal pressure P of 2_BAnd internal pressure P of blast furnace 1_CBased on the inge
Internal pressure P of the injection tank 12_BAnd internal pressure P of blast furnace 1 _C
Carrier gas quantity Q that keeps the differential pressure of_FIs calculated.
Gas delivery Q_FIs supplied to the flow controller 54 as a set value.
As a result, the flow rate control
The fine powder conveyed in the transport pipe 13 by controlling the control valve 21
The amount of coal is controlled.

As described above, the injection tank 12
4A, the detection value L _U of the service tank 11 decreases with the lapse of time as shown in FIG.
The weight detection value L _L of the second color increases as shown in FIG.
Although the inner pressure P _B of the injection tank 12 will increase as indicated by the characteristic curve L1 in FIG. 5 at a time t ₂ from the service tank 11 was started pulverized coal supply to the injection tank 12, the internal pressure P _B the increased, although the pulverized coal cutting amount of the injection tank 12 will increase, carrier gas amount Q _F computed by the carrier gas quantity calculator 52 of the carrier gas controller 36 at this time is FIG. 5
As shown by the characteristic curve L2 of FIG.
Increased in response to increase in the second pressure P _B, by the differential pressure between the merging point pressure P _D of the internal pressure P _B and the transportation pipeline 13 of the injection tank 12 is reduced accordingly, from the injection tank 12 The pulverized coal cut-off amount is suppressed, and even when the internal pressure control due to the change in the weight of the injection tank 12 is interrupted, the pulverized coal constant supply state of the blast furnace 1 can be secured, and the furnace top gas of the blast furnace 1 can be secured. As shown by the characteristic curve L3 in FIG. 5, the pressure fluctuation of H ₂ can be reduced from the conventional ± 0.5% fluctuation to ± 0.1% fluctuation. The characteristic curve L in FIG.
4 represents a change in the weight of the injection tank 12.

Similarly, with pulverized coal charged, the internal pressure of the blast furnace 1
P_CIf the pressure fluctuates for some reason, the internal pressure P_C
And the internal pressure P of the injection tank 12_BAnd differential pressure
To be constant_FIs controlled, so high
Ensure that a fixed amount of pulverized coal is injected regardless of fluctuations in furnace pressure.
Can be. Fine powder into this injection tank 12
By maintaining the charcoal charging state, the service tank 11
Weight detection value L_UT decreases to reach the set value S3
_Three, The lower electromagnetic on-off valve 11 of the service tank 11
b is controlled to a closed state, and the on-off valve 11b is completely closed.
After that, the solenoid on-off valve 11d is controlled to open.
The internal pressure P of the service tank 11_AIs gradually lowered,
Exhausted pressurized gas (N _Two) Turns through the exhaust pipe 11f.
Collected by a collecting device.

[0037] Then, when t ₄ when the internal pressure P _A of the service tank 11 is at atmospheric pressure, exhaust pressure solenoid valve 11d is controlled to a closed state, the upper solenoid valve 11a is controlled to the open state at the same time as this At the same time, the pulverized coal pulverizer is started, and the supply of pulverized coal to the service tank 11 is started,
This weight measurement value L _U service tank 11 is rapidly increased as shown in FIG. 4 (a), at time t ₅ that the weight detected value L _U has reached the upper limit set value L _MAX is driven pulverized coal pulverizer At the same time, the upper opening / closing valve 11a is controlled to be closed, and the pulverized coal charging process ends.

Thereafter, at time t ₆ after a predetermined time has elapsed, the closing state signal ST returns to the off state, whereby the selection circuit 48 of the injection tank internal pressure control unit 35 sets the internal pressure set value output from the internal pressure set value calculator 46. By selecting the value SV, the internal pressure control state by the internal pressure holding value of the hold circuit 47 is released as shown in FIG.
With returns to the normal state for controlling the blowing amount based on the weight change of the injection tank 12, by selecting the carrier gas amount Q _F of carrier gas amount calculating unit 51 by the selection circuit of the carrier gas controller 36, blow amount W It returns to the normal state in which the amount of carrier gas is controlled based only on the condition.

In the above embodiment, the control device 3
Although the case where only the pulverized coal input control unit 37 constituting 0 is constituted by the microcomputer has been described, the present invention is not limited to this, but the injection amount setting unit 34, the injection tank internal pressure control unit 35, and the transport gas control unit 36 May be configured by a microcomputer, a programmable controller, or the like.

Further, in the above embodiment, the case where the pulverized coal supply device 10 is constituted by the two service tanks 11 and the injection tanks 12 which are vertically connected in series has been described. However, the present invention is not limited to this. 3
One or more tanks may be connected in series. Further, in the above-described embodiment, the case where the present invention is applied to the pulverized coal gas transport device to the blast furnace was described. However, the present invention is not limited to this, and the granular material is transported to another high pressure supply destination by gas. The present invention can be applied to such cases.

As described above, the method for controlling the transport of the granular material according to the present invention is based on the detected value of the change in weight of the lower tank when the charging of the granular material from the upper tank to the lower tank is stopped normally. Control the internal pressure of the lower tank to control the amount of the granular material transported. When the granular material is charged from the upper tank to the lower tank, the differential pressure between the internal pressure of the lower tank and the internal pressure of the supply destination container is reduced. Since the amount of powder and granular material transported was controlled by controlling the amount of transport gas to be constant,
When the amount of the granular material in the lower tank is reduced and the granular material is replenished from the upper tank, even if the change in the weight of the lower tank is not proportional to the amount of the granular material transported, at least the lower tank and the transport destination container are required. when the pressure variation in either one has occurred, by controlling the carrier gas amount so as to maintain Ru constant differential pressure therebetween, it is possible to suppress the fluctuation of the granular material conveyance amount, to the supply destination container The effect is obtained that the gas can be conveyed with a high degree of accuracy.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an apparatus for transporting pulverized coal gas to a blast furnace to which the present invention can be applied.

FIG. 2 is a system diagram illustrating an example of a control device that controls each unit in FIG. 1;

FIG. 3 is a flowchart illustrating an example of a processing procedure of a pulverized coal input control unit in the control device.

FIG. 4 is a time chart for explaining a pulverized coal conveying method.

FIG. 5 is a time chart showing a lower tank internal pressure, a carrier gas amount, a furnace top gas pressure, and a lower tank weight change in a pulverized coal input state.

FIG. 6 is a characteristic diagram showing a relationship between a pulverized coal injection amount and a differential pressure between an injection tank internal pressure and a junction pressure.

[Explanation of symbols]

 Reference Signs List 1 blast furnace 2 tuyere 4 pulverized coal blowing burner 5 pressure sensor 10 pulverized coal supply device 11 upper tank 11a, 11b, 11d solenoid on-off valve 12 lower tank 13 transport pipe 14 carrier gas supply pipe 15 pressurized gas supply pipe 16, 18 load Sensor 17, 19 Pressure sensor 21 Flow control valve 23, 24 Pressure control valve 30 Control device 34 Blow amount setting unit 35 Lower tank internal pressure control unit 36 Carrier gas control unit 37 Pulverized coal input control unit

Claims (1)

(57) [Claims] 1. A method for transporting a granular material, comprising an upper tank and a lower tank for storing the granular material connected in series, wherein the granular material in the lower tank is transported by a transport gas to a supply container. In the control method, when the charging of the granular material from the upper tank to the lower tank is normally stopped, the transport amount of the granular material is controlled by controlling the internal pressure of the lower tank based on the detected value of the change in weight of the lower tank. When the granular material is charged from the upper tank to the lower tank, the transport amount of the granular material is controlled by controlling the amount of the transport gas so that the differential pressure between the internal pressure of the lower tank and the internal pressure of the supply destination container is constant. A method for controlling the transfer of a granular material, comprising: