JPH0134901B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a device for pneumatically feeding pulverized coal to, for example, the tuyere of a blast furnace. In smelting iron ore in blast furnaces, coke has traditionally been the material used to provide the carbon and also to generate the necessary heat during the smelting process. Coke, which generally accounts for about one-third of the contents in a furnace, is a very expensive and essential item in the production of iron. Therefore, it is important from an economic point of view to replace some of the used coke with cheaper coal. Various prior art techniques are utilized to inject pulverized coal into blast furnaces, thereby replacing a portion of the coke currently in use with pulverized coal. A conventionally well-known pulverized coal pneumatic conveying device is shown in FIG. The device configuration shown in FIG.
A lump coal supply device 4 consisting of a bunker 2 and a cutting feeder 3 pulverizes and dries the lump coal continuously introduced from the cutting feeder 3 while introducing heated air from an air heater 5 to a pneumatic pipe 6. a pulverizer 7 that pneumatically discharges the pulverized coal, a separator 10 that separates the pneumatic pulverized coal from the pneumatic pipe 6 using a cyclone 8 and a bag filter 9, and separates the pulverized coal separated by the cyclone 8 and bag filter 9 into rotary Duct 1 with valves 11 and 12 and on-off valves 13 and 14 interposed
From the storage tank 17, pulverized coal is introduced in a predetermined order through a three-pronged duct 22 having on-off valves 19 to 21, and when a predetermined amount of pulverized coal is introduced, the upper part Inert gas is introduced from (not shown) to maintain the predetermined pressure, and inert gas is also introduced (not shown) to the lower part of the tank 23a to pneumatically discharge the pulverized coal from the lower discharge port. 2
3c, and the pulverized coal pneumatic flow from the lower discharge ports of each of the tanks 23a to 23c is supplied from the cutout pipes 24a to 24b, the cutout main pipe 27, and the separate heated air supply source 33 interposed with the valves 25a to 25c. The heated air is introduced through a diluter 26 to adjust the dilution of the pulverized coal pneumatic flow through a main pipe 27' and distributed to each of the distribution branch pipes 28 connected to distribution openings provided in the peripheral wall. and a distribution device 32 that blows air into the furnace from a nozzle 31 in the blast tuyere 30 of the blast furnace 29. The basic method of controlling the extraction of pulverized coal from the tank in such a conventional device is to adjust the internal gas pressure of the tank to be extracted. However, the pulverized coal is cut out from the tank in a so-called solid/gas two-phase flow with the carrier gas and supplied to the receiving side blast furnace, etc., so the amount of cut out depends on the blowing pressure inside the blast furnace and the gas pressure inside the tank. Even if the value is stable, it is difficult to adjust the amount of cut out according to the internal gas pressure adjustment, and it fluctuates greatly. this is,
This is due to the fact that, unlike a one-phase fluid, it is accompanied by unique phenomena such as thick/light pulsation, sedimentation, solid/gas separation flow, and intermittent flow of pulverized coal. Figure 2 A shows blast furnace blast pressure P _B
Figure 2 (b) shows an example of a state in which the tank internal gas pressure T _P is constant and the pulverized coal output amount T _X is relatively stable and fluctuates. The inventors of the present invention obtained the following findings as a result of various experiments and studies aimed at alleviating the above phenomenon. Even if the pressure inside the tank and on the pulverized coal loading side (for example, the blast furnace tuyere side) is constant, the amount of pulverized coal cut out from the tank fluctuates, but this can be adjusted by adjusting the deviation between the actual cutout amount and the target cutout amount. Because the pressure inside the tank is controlled by increasing or decreasing the pressurized gas based on the The speed at which the amount of charcoal cut begins to change and reaches the target value is slow, and therefore, this control causes a so-called hunting phenomenon in which over-cutting and under-cutting are repeated and is unstable. When switching the target tank for pulverized coal cutting, the flow of pulverized coal to the main cutting pipe changes suddenly depending on the opening/closing timing of the opening/closing valve of the corresponding tank's cutting pipe, resulting in concentration pulsation, solid/gas separation flow, and pulverized coal intermittent. This causes phenomena such as flow and sedimentation, which significantly impedes the supply of pulverized coal in a fixed amount to the blast furnace, and has a large effect on the stable operation of the blast furnace. The present invention has been made based on these new findings. That is, the present invention uses a pulverized coal cutting control device and a cumulative deviation correction device that solve the above problems, and an on-off valve switching device that solves the above problems to constantly supply a predetermined amount of pulverized coal accurately and stably to the pulverized coal side. The present invention provides a pulverized coal pneumatic conveying device, and its features are as follows: (1) Pulverized coal is charged into each of a plurality of tanks from the top, and the pulverized coal is cut out from the bottom of each tank and transferred to a pipe. In a pulverized coal pneumatic conveying device that sequentially switches between pressurized cutting and cutting, the pulverized coal is supplied to the tuyere of a blast furnace through a pipe line with a dilution pipe and a distribution device, and for each of the tanks, a The gas weight in the tank is calculated based on the detected value from the installed load detector, the pressure detected from the tank pressure detector, and the inert gas supply connected to the tank is calculated by multiplying the above pressure detected value by a proportionality constant. A pulverized coal amount calculation device that calculates the amount of pulverized coal in the tank based on the value of the reaction force of the tube expansion; A cutting amount calculating device that calculates the amount of pulverized coal cut out per unit time from the indicating tank by sequentially introducing the measured value of the amount of pulverized coal from the indicating tank from the pulverized coal amount measuring device, a predetermined cycle from the cutting amount calculating device. Introduce the calculated value of the pulverized coal cutting amount of the tank during pulverized coal cutting, and this will be set above and below the target cutting amount to the blast furnace on the pulverized coal injection side, which is introduced separately from the target cutting amount setting device. Whenever it deviates from the non-control band set with a predetermined width, the deviation from the target cutting amount is calculated, and this deviation is corrected by multiplying it by a control sensitivity constant of less than 1, and the next calculated value of the fine powder cutting amount is calculated. By the time of introduction, based on this corrected deviation value, the pulverized coal cutting amount calculation value from the pulverized coal cutting control device that controls the pressure regulating valve and the cutting amount calculating device is sequentially introduced, and the target cutting amount is set. The target cutting amount from the vessel is introduced one after another, each time it is compared with the calculated cutting amount, the deviation is calculated, and this deviation is accumulated in a predetermined time unit, and this cumulative value is calculated each time. A cumulative deviation correction device that is installed in the target cutting amount setting device and sequentially corrects the target cutting amount set within the next predetermined time at predetermined time intervals; The measured value of the amount of pulverized coal in the tank is sequentially introduced, and when this reaches the preset lower limit value, the on-off valve installed in the lower cut-out pipe of the tank waiting to be cut is opened, and after it is fully opened, the pulverized coal is removed. An on-off valve switching device that closes and fully closes the on-off valve installed in the cut-out pipe at the bottom of the tank during cutting, switching the pulverized coal cutting tank, and as a tank exhaust pressure valve at the end of pulverized coal cutting. In contrast, there is a gradual decrease setting device that gradually decreases the tank internal pressure setting value to atmospheric pressure, and a gradual increase setting device that gradually increases the tank internal pressure value to the pressure valve of the tank at the end of pulverized coal charging. When a value close to that value is reached, this value is continuously set while waiting for pulverized coal cutting, and then gradually increased again until it matches the tank internal pressure value during pulverized coal cutting at a predetermined time before the start of pulverized coal cutting. A device for pneumatically feeding pulverized coal to a blast furnace, characterized in that it is equipped with an in-tank pressure control device and the following. (2) The pulverized coal amount measuring device calculates the value obtained by subtracting the gas weight in the tank and the tank's own weight from the load detection value from the load detector installed in the tank support, and calculates the value from the tank pressure detector installed in the tank. The apparatus for pneumatically feeding pulverized coal to a blast furnace according to item (1) above is characterized in that the amount of pulverized coal in the tank is calculated by correcting the detected pressure value. The present invention will be explained in detail below with reference to embodiments shown in FIGS. 3 to 7. FIG. 3 is an explanatory diagram in which one embodiment of the present invention is applied to the essential parts of the apparatus shown in FIG. 1. In FIG. 3, each tank 23a, 23b, 2
3c, the control device CPU switches and controls the cycle of charging a predetermined amount of pulverized coal from the storage tank 17 shown in FIG. pulverized coal is continuously blown into the blast furnace.

[Table] In the control device CPU, charging a predetermined amount of pulverized coal is
The measured value of the amount of pulverized coal in the tank (ta _{to tc} ) from the pulverized coal amount measuring device 101 is the lower limit value set in advance.
_{The three - pronged _ _} The storage tank 17 is opened by opening the on-off valves (19, 20, 21 shown in FIG. 1) for the tank installed in the duct 22.
The process starts by letting the pulverized coal fall under its own weight while fluidizing it, and when the measured value of the pulverized coal amount (t _a to t _c ) reaches the upper limit value _U0 , the on-off valves 19, 20, and 21 are closed to reduce the pulverized coal. Coal charging is completed and instruction signals SE23a to SE23c are sent to the tank to be completed. Pulverized coal cutting standby occurs when the measured value of the amount of pulverized coal (t _a - t _c ) in the tank during pulverized coal cutting is less than the preset lower limit L ₀ from the time when the specified amount of pulverized coal charging is completed. , the pressure detector P _a ~ P _c in the tank concerned
AND that the detected pressure values (P ₁ to P ₃ ) from the pulverized coal match the detected pressure values (P ₁ to P ₃ ) from the pressure detectors P _a to P _c in the tank during pulverized coal cutting. Continue until the conditional point. The pulverized coal cutting is performed by sending an instruction signal S23a to the corresponding tank at the end of the pulverized coal cutting standby of the corresponding tank.
S23c is sent, and from this point on, the process is continued until the measured value of the amount of pulverized coal in the tank (ta _{to tc} ) reaches the lower limit value _L0 , and when the lower limit value is reached, the instruction signals HE23a to HE23c for the tank are sent. do. The pulverized coal measuring device 101 detects the detected values W ₁ (W ₁ -
W ₃ ) and the calculated value of the gas weight in the tank based on the detected values P _N (P ₁ to _{P 3} ) from the tank pressure detectors P _a to _{P c}
W ₂ and various piping (inert gas supply pipe 103) calculated by multiplying the detected value P _N (P ₁ to _{P 3} ) by a proportional constant K
a~103c, 104a~104c, exhaust pipe 10
5a to 105c, three-pronged ducts 22a to 22c, and cutout pipes 24a to _24c ), each tank 23a to The pulverized coal accommodation weight W ( _ta to _tc ) in 23c is calculated in a predetermined cycle. W=W ₁ −W ₂ −K·P _N As a result, the amount of pulverized coal in each tank 23a to 23c can be accurately measured. The cutting amount calculation device 108 receives the tank instruction signal S23a from the control device CPU to start cutting out pulverized coal.
~S23c determines the pulverized coal amount measurement value (t _a ~ t _c ) of the corresponding indicating tank from the pulverized coal amount measuring device 101.
is sequentially introduced to calculate the amount of pulverized coal cut out per unit time (T _a to T _c ) from the indicated tank. Next, the pulverized coal cutting control device 109 will be explained. Even if the amount of pulverized coal that is actually cut out deviates from the target cutout amount, if the pressure inside the tank is rapidly variably controlled in order to suddenly change it to the target cutout amount, the cutout pulverized coal Concentration separation of the flow and intermittent flow phenomena of pulverized coal take a long time to stabilize, and in some cases, blockage accidents may occur, making stable injection into the blast furnace impossible. The pulverized coal cutting control device 109 prevents this, and controls the target cutting amount (18~
20ton/Hr) above and below the uncontrolled band (±
0.5ton/Hr), introduce the actual cutting amount in a predetermined cycle, detect whether or not it deviates from the non-control band each time, calculate the deviation from the target cutting amount only when it deviates from the non-control band, and calculate the deviation. By sequentially applying a control amount smaller than the tank internal pressure control amount that reduces the amount to 0 until the next actual cutting amount is introduced, a stable pulverized coal flow is always maintained and safety is avoided without the above problems. This enables stable injection of pulverized coal into the blast furnace. In this example, the pulverized coal cutting amount (T _a to T _c ) of the corresponding tank is calculated from the cutting amount calculating device 108 based on the tank instruction signals S23a to S23c for starting pulverized coal cutting from the control device CPU. The target cutting amount (or blowing amount) is introduced in a predetermined cycle, and if it deviates from the non-control band ±α of the target cutting amount A ₀ separately introduced from the target cutting amount (or blowing amount) setting device 110, the deviation from the target cutting amount A ₀ is determined each time. Calculate this, multiply it by a control sensitivity constant less than 1, correct it, calculate the tank internal pressure variable amount corresponding to this correction value, use this to correct and change the tank internal pressure set value, and Based on pressure detector
Pressure regulating valve 1 is set so that the detected pressure values (P ₁ to _{P 3} ) from P _a to _{P c} become the tank pressure set value for the correction change.
This is to feedback control the opening degrees of 11a to 111c. Further, the target cutting amount A ₀ is introduced into the pulverized coal cutting control device 109 from the target cutting amount setting device 110, and the initial pressure setting value in the tank is stored in advance in the memory for each tank. It is selected from the relationship table between the cutout amount (ton/Hr) and tank internal pressure value (Kg/cm ² ) shown in FIG. Shoben Y111a~Y
111c is always set at a predetermined opening degree and supplies inert gas to the lower part of the tank to make the pulverized coal float and flow, thereby preventing clogging of the pulverized coal and reducing the amount of gas for conveyance during cutting. Adjust. Next, the cumulative deviation correction device 112 will be explained. Due to the above-mentioned cutting control, the actual cutting amount may be too much or too little compared to the target cutting amount per hour or per day, causing a major problem in the control of the amount of heat in the blast furnace, for example, on the pulverized coal injection side. This may have a significant negative impact on blast furnace operations. The cumulative deviation correction device 112 solves this problem. That is, the cumulative deviation correction device 112
Based on the tank instruction signals S23a to S23c for starting pulverized coal cutting from the CPU, the pulverized coal cutting amount (T _a to T _c ) of the corresponding instruction tank is sequentially introduced from the cutting amount calculating device 108 to the comparison section. At the same time, the target cutting amount A ₀ (mainly changed due to changes in blast furnace air flow rate) is also introduced from the target cutting amount setting device 110, these are compared, and the deviation is introduced into the addition/subtraction section. and accumulate. This accumulation is performed in units of T ₀ for a predetermined period of time set by timer T (for example, 3 to 4 minutes),
Each time, the cumulative value is introduced into the multiplication section [0<G<1]
The resultant ΔS is introduced into the target cutting amount setter 110 to set the target cutting amount, which is separately commanded during the time T ₀ next to the predetermined time T ₀ . The command value is corrected and controlled to be output from the setting device 110 to the pulverized coal cutting control device 109. Next, the switching control of the corresponding on-off valve when switching the cut-out of the tank is conventionally performed as shown in Fig. 5A, when the amount of pulverized coal in the tank currently being cut out reaches the lower limit, the signal L ₀ is activated. At the same time, the on-off valve V _o provided in the cut-out pipe of the tank being cut out is closed (solid line ₀ ), and at the same time the open-close valve V o provided in the cut-out pipe of the tank waiting to be cut is closed. Since valve V _o+1 was kept open (solid line ₀ ), the change in the amount of pulverized coal cut out (ton/hr) from each tank at the time of this switching was as shown by the solid line a ₀ (solid line 0). tank), the dotted line b ₀ (tank that was on standby), and as a result of these changes, the total pulverized coal output amount greatly decreases with respect to the target output amount A ₀ , as shown by the solid line A _a . wake up For this reason, the inventor of the present invention conducted various experiments and studies in order to completely eliminate this variation, and as a result, the on-off valve switching device 1
13 was obtained, and the fluctuation was completely eliminated. That is, when the on-off valve switching device 113 sequentially switches the tanks from which pulverized coal is to be cut according to the table above, the on-off valve switching device 113 switches between the tank from which pulverized coal has been cut and the tank from which pulverized coal has been waiting until now. The on-off valves for cutting are controlled as shown in FIG. This allows the tank to be switched. In addition, if two on-off valves are installed in each cut-out pipe, as shown in Fig. 5B, the standby tank is opened and closed for backup as shown in solid line ₀₀ at the same time as the on-off valve 114b is opened as shown in solid line ₀ . Close the valve Y114a,
After these operations are completed, the tank that has been cut out until now will close the on-off valve 114a as shown by the solid line ₀ , and at the same time close the on-off valve Y as shown in the solid line ₀₀ .
114b is opened and these operations are completed, the amount cut out from the tank 23a is the solid line a ₀ ′,
The amount cut out from the tank 23b is the dashed line b ₀ ′,
The amount of pulverized coal cut out in the main cutting pipe 27 is shown by the solid line.
As shown by A _a ', there is a large variation with respect to the target cutting amount A ₀ . In other words, the on-off valve switching control device 11 in FIG.
3 is the corresponding tank instruction signal S23a to S23c for starting pulverized coal cutting from the control device CPU, for example, 23
In accordance with the instruction signal S23a of pulverized coal amount measuring device 101, the measured value T _a of the amount of pulverized coal in the tank 23a to be indicated is sequentially introduced, and when this reaches the preset lower limit value _L0 , the As shown in Figure 6A, a tank waiting to be cut out, for example, the lower cutout pipe 24 of 23b
After _opening the on-off valve 114b installed at b and fully opening to the specified value, the on-off valve 114a installed at the lower cut-out pipe 24a of the tank 23a from which pulverized coal has been cut out until now is closed (solid line 1). Fully closed (solid line ₁ )
At the very least, the tank switching is completed. As a result, the amount cut out from the tank 23a is the solid line.
a ₁ , the amount of pulverized coal cut out from the tank 23b is shown by a dashed-dotted line b ₁ , and the amount of pulverized coal cut out in the main cutting pipe 27 where the cutting pipes 24 a to 24 c merge and connect just before the thinner 26 is shown by a solid line A ₁ As such, there is almost no variation with respect to the target cutting amount _A0 . Also, the on-off valves Y114a to Y1 indicated by dotted lines in FIG.
When installed as a backup on the upstream side of the on-off valves 114a to 114c as shown in FIG. 6B, as shown in _FIG .
After the on-off valve Y14b is fully opened, the on-off valve Y114b shown in the solid line ₂ is opened until the solid line ₁ on-off valve 114a starts closing operation.
After the valve Y114a is fully opened to the specified value, the on-off valve Y114a shown in solid line ₂ is closed, and the amount of cutout from the tank 23a is the solid line a ₂ and the amount of cutout from the pressure tank 23b is one point. The chain line b ₂ is the amount of pulverized coal cut out from the main cutting pipe 27.
As shown by _A2 , there is almost no variation with respect to the target cutting amount _A0 . In other words, if two or more on-off valves are installed in the cut-out pipe, all on-off valves on the tank side during standby are fully opened, and then all on-off valves on the tank side that have been cut out until now are closed simultaneously or sequentially. By fully closing the main pipe 27, the target cutting amount can be achieved without constantly changing the cutting amount of pulverized coal in the main cutting pipe 27.
It is possible to maintain and stabilize A ₀ continuously. In addition, the time T _i shown in Fig. 6 A and B, that is, the on-off valve 11
The time between the time when the valve 4b is fully opened and the time when the on-off valve 114a starts its closing operation may be set to, for example, 0 to 10 seconds. Then, the amount of cutout increases rapidly and overlaps, which is not preferable. Next, the tank internal pressure control device 115 controls the exhaust pressure before the start of pulverized coal charging, which is performed before pulverized coal is again cut out from the tank after pulverized coal has been cut out, and the waiting period for cutting after pulverized coal charging. Gradually variably controls the charging (pressurization) of the gas, and the adiabatic expansion of the gas due to rapid increase and exhaust pressure prevents rapid cooling embrittlement damage to the exhaust pressure piping and the joint between it and the tank, and the accuracy of measuring the amount of pulverized coal in the tank. In addition to suppressing the occurrence of abnormal noise, etc., disturbances to the cutting control such as decreases in the cutting amount control, such as decreases in the measurement accuracy of pulverized coal in the same tank as described above due to rapid pressurization, and disturbances to the cutting control, such as decreases in the measurement accuracy of pulverized coal in the same tank as described above due to rapid pressurization, This prevents the inert gas supply device from becoming larger due to excessive use of active gas for a short period of time. That is, the tank internal pressure control device 115 introduces tank instruction signals HE23a to HE23c, for example HE23a, for completion of pulverized coal cutting from the control device CPU, and exhaust pipe 105a of this instruction tank 23a.
The pressure detection value P ₁ is introduced into the exhaust pressure valve 116a, and the pressure setting value in the tank is set to gradually decrease from the time when the pressurizing valve 117a is closed to the atmospheric pressure value at the exhaust pressure speed M _X of 1 kg/cm ² /min or less. A setting device 115A,
Instruction signals SE23a to SE23c from the control device CPU for the target tank where pulverized coal charging has been completed, for example SE2
3a is introduced and the tank internal pressure set value is 0.7Kg/ for the pressure regulating valve 111a of this indicator tank 23a.
The pressurization speed M ₁ of cm ² /min or less is gradually increased, and when the blowing pressure P _B to the blast furnace 29 tuyere 30 to which the pulverized coal is injected is reached, this is maintained continuously while the pulverized coal is waiting to be cut, and the controller CPU A predetermined time before the start of pulverized coal cutting from the pulverized coal, the signal SB is used to set the gradual increase again, and when this matches the detected pressure value P ₃ from the pressure detector P _C inside the separately introduced tank during pulverized coal cutting, for example, 23c. It has a gradual increase setting device 115B that maintains this.
The SB signal from the control device CPU is transmitted when the measured value t _c of the amount of pulverized coal in the tank 23c during pulverized coal cutting shows a value larger than the lower limit value L ₀ by a predetermined amount β. In addition, the air blowing pressure P _B is the air blowing annular pipe (Fig. 1 R).
The target value may be set to a value that is sequentially measured within the target range, or a target value may be set to a fixed value. FIG. 7A shows an example of gradual increase/decrease control during pressurization/discharge of the tank internal pressure control device 115.
Exhaust pressure valve opening pattern PK.PH, tank internal pressure (Kg/cm ² ) change pattern PP, temperature (°C) change pattern PT at the connection between exhaust pipe 105a and pressure tank 23a, amount of pulverized coal in pressure tank 23a Measured value t _a
The change patterns of P _tpo are shown respectively. In FIG. 7B, the gradual decrease setting device 115A and the gradual increase setting device 115B are not provided, and the exhaust pressure valve 116a and the pressurization valve 117a are turned on.
The above-mentioned patterns in the case of OFF-like opening/closing operations are shown as comparative examples, and patterns corresponding to those in FIG. As is clear from this figure, the pressure control device 115
According to the above, it is possible to reliably prevent vibrations caused by a sudden increase in dynamic pressure inside the tank during exhaust pressure and pressurization, as well as rapid cooling of the connection part, thereby stabilizing the above-mentioned pulverized coal amount measurement accuracy and cutting control. The purpose is to completely eliminate quenching embrittlement of the joints and ensure their safety. As is clear from the above description, the device of the present invention uses the cutting control device to perform control such that the actual cutting amount matches the target value of the pulverized coal cutting amount, as in the conventional method, by constantly adjusting the control based on these deviation values. Relaxation control that calculates the deviation only when measuring the actual cutting amount that deviates from the non-control band of the target value at predetermined time intervals, and multiplies it by a control sensitivity of 1 or less instead of feeding it back as is. By doing
It suppresses discontinuous pulverized coal flow such as solid/gas separation concentration pulsation flow in the cut pulverized coal flow, prevents the hunting phenomenon, and continuously maintains a stable and normal cut pulverized coal flow, reducing the cumulative deviation. The correction device adjusts the deviation between the target value and the variable actual cutting amount in the non-control band that cannot be controlled by the cutting control device, and the actual cutting amount outside the non-control band within the predetermined time period. The target cutting amount is accumulated on a daily basis, and the target cutting amount is successively corrected for the next predetermined time or day, thereby stabilizing the heat management at the injection destination of a blast furnace, etc., and establishing smooth operation. In addition, the on-off valve switching device switches the on-off valve of the waiting tank (when there are two or more, the most downstream side) before closing the on-off valve of the pressure tank that is currently being cut (the most downstream side when there are two or more). By opening all valves (all valves) and completing the full opening, the switching can be carried out without changing the amount of pulverized coal cut out and maintaining a stable pulverized coal cutting flow. It is something that brings it to completion. In addition, the tank internal pressure control device gradually decreases the exhaust pressure in the tank and gradually increases the charging pressure in the tank, thereby preventing tank vibration, noise, and rapid cooling embrittlement of the exhaust pressure pipe connection. This greatly contributes to improving the accuracy of measuring the amount of pulverized coal and stabilizing the control of other cutting tanks. Further, as a pulverized coal amount measuring device, as shown in the above formula, the detected pressure inside the tank is used as the main correction term to obtain more accurate measurement results and to stabilize the control accuracy of each device to a higher level. With these configurations, the supply of pulverized coal to the pulverized coal injection side is always carried out while stably maintaining a desired amount of pulverized coal flow in an appropriate state, thereby making the operation of the pulverized coal injection side advantageous and highly stable.

[Brief explanation of drawings]

Fig. 1 is a schematic explanatory diagram showing an example of a pulverized coal pneumatic conveying device, Fig. 2 A and B are graphs showing the state of extraction from a tank, and Fig. 3 shows the main parts of Fig. 1 according to the present invention. 1
Figure 4 is a graph showing an example of the relationship between the tank internal pressure and the amount of pulverized coal cut out. FIG. 6A and B are explanatory diagrams showing cut-out amount patterns, and FIG. B is the exhaust pressure valve by the tank internal pressure control device according to the present invention;
An explanatory diagram showing the opening/closing pattern of the pressurizing valve, the pressure transition pattern in the tank, the temperature pattern at the connection part between the exhaust pipe and the tank, and the inference pattern of the measured value of the amount of pulverized coal in the tank. FIG. 7 is an explanatory diagram showing the opening/closing pattern of the pressure valve, etc. in comparison with FIG. 7A; 1: conveyor, 2: bunker, 3: cutting feeder, 4: lump coal supply device, 5: air heater,
6: pneumatic pipe, 7: crushing device, 8: cyclone,
9: Bag filter, 10: Separation device, 11,1
2: Rotary valve, 13, 14: Open/close valve, 1
5, 16: Duct, 17: Storage tank, 19-21:
On-off valve, 22: Three-pronged duct, 23: Tank, 2
4: Cutting pipe, 25: Valve, 26: Dilution pipe, 27: Main pipe, 28: Branch pipe, 29: Blast furnace, 30: Blowing tuyere,
31: nozzle, 32: distribution device, 33: heated air supply source, 101: pulverized coal amount measuring device, 102: pressure detector, 103, 104, 105: inert gas supply pipe, 107: expansion pipe, 108:
Cutting amount calculation device, 109: Pulverized coal cutting control device,
110: target output amount setting device, 111: pressure regulating valve, 112: cumulative deviation correction device, 113: on-off valve switching device, 114: on-off valve, 115: tank internal pressure control device, 116: exhaust pressure valve.

Claims (1)

[Scope of Claims] 1. Pulverized coal is charged into each of a plurality of tanks from the upper part thereof, and the pulverized coal is cut out under pressure from the lower part of each tank into a cutting pipe. In the pulverized coal pneumatic conveying device that supplies the pulverized coal to the tuyere of the blast furnace through a pipe line with a distribution device, the detection value from the load detector installed in the tank support and the pressure sensor inside the tank are detected for each tank. Based on the calculated value of the gas weight in the tank based on the detected pressure value from , a pulverized coal amount calculation device that calculates the amount of pulverized coal in the tank, and a pulverized coal amount measurement value in the designated tank from the pulverized coal amount measurement device in response to a tank instruction signal to start pulverized coal cutting from a higher-level control device. A cutting amount calculation device that is sequentially introduced and calculates the amount of pulverized coal cut out per unit time from the instruction tank, and a calculated value of the pulverized coal cutting amount of the tank in which pulverized coal is being cut out in a predetermined cycle from the cutting amount calculation device. is introduced, and this sets the target cut-out amount to the blast furnace on the pulverized coal injection side, which is introduced from a separate target cut-out amount setting device.
Whenever the non-control band set below with a predetermined width is exceeded, the deviation from the target cutting amount is calculated, and this deviation is corrected by multiplying by a control sensitivity constant of less than 1 to calculate the next fine powder cutting amount. Based on this corrected deviation value, the pulverized coal cutting amount calculation value from the pulverized coal cutting control device that controls the pressure regulating valve and the cutting amount calculating device is sequentially introduced, and the target cutting amount is set. The target cutting amount from the amount setting device is introduced sequentially, and each time it is compared with the calculated cutting amount value, the deviation is calculated, and this deviation is accumulated in predetermined time units, and each time, this cumulative amount is calculated. A cumulative deviation correction device that inputs the value into the target cutting amount setting device and sequentially corrects the target cutting amount set within the next predetermined time at predetermined time intervals; The measured value of the amount of pulverized coal in the tank that is being discharged is introduced one after another, and when this reaches a preset lower limit value, the on-off valve installed in the lower cut-out pipe of the tank that is waiting for cut-out is opened, and after it is fully opened. An on-off valve switching device that closes and fully closes the on-off valve installed in the cut-out pipe at the bottom of the tank during pulverized coal cutting, switching the pulverized coal cutting tank, and draining the tank at the end of pulverized coal cutting. A gradual decrease setting device sets the pressure setting value in the tank to gradually decrease to atmospheric pressure for the pressure valve, and a gradual increase setting device sets the pressure setting value in the tank for the pressurization valve of the tank at the end of pulverized coal charging. When the internal pressure reaches or a value close to it, this is set to continue while waiting for pulverized coal cutting,
A tank internal pressure control device is provided with a gradual increase setting device that increases the pressure again until it matches the tank internal pressure value during pulverized coal cutting a predetermined time before the start of pulverized coal cutting. Pulverized coal pneumatic conveying device to the blast furnace. 2 The pulverized coal amount measuring device calculates the value obtained by subtracting the gas weight in the tank and the tank's own weight from the load detection value from the load detector installed in the tank support, and calculates the pressure detected by the tank pressure detector installed in the tank. A device for pneumatically feeding pulverized coal to a blast furnace according to claim 1, wherein the amount of pulverized coal in the tank is calculated by correcting the value.