Method and device for controlling pressure of pulverized coal bunker of blast furnace coal injection system

Abstract

The invention belongs to the technical field of blast furnace ironmaking in the ferrous metallurgy industry, and relates to a pulverized coal bunker pressure control method and device of a blast furnace coal injection system. By establishing an injection tank pressure relief control model and a pulverized coal bunker pressure control model, the pulverized coal bunker pressure is adjusted through the two models in the injection tank pressure relief execution period; the pressure of the pulverized coal bunker is accurately controlled to be in a micro-negative pressure state. The system has the advantages that the pressure of the pulverized coal bunker is accurately controlled, stable production of the system can be guaranteed, independent production of the coal pulverizing system and the injection system can be achieved, meanwhile, the automatic control level of the system is greatly improved, the workload of operators is reduced, and remarkable technical and economic benefits are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of blast furnace ironmaking in the iron and steel metallurgical industry, and relates to a pulverized coal bin pressure control method and device for a blast furnace coal injection system. Background Art

[0002] Blast furnace coal injection is the use of cheap coal powder to partially replace expensive coke. It is an effective measure to save coke and reduce costs in the blast furnace ironmaking process and improve product competitiveness. The blast furnace coal injection system consists of two subsystems: the pulverizing system and the injection system. The qualified coal powder produced by the pulverizing system flows from the ash bin of the coal powder collector to the coal powder bin by gravity for temporary storage, and then the coal powder flows from the coal powder bin by gravity to the injection tank for continuous injection. Therefore, the coal powder bin is an important connecting equipment between the pulverizing system and the injection system.

[0003] At present, the mainstream injection system adopts a pulverized coal bunker with a group (≥2) of parallel injection tanks under the bunker. Each injection tank works alternately in the procedure of injection-pressure relief-coal loading-pressurization-waiting, and the injection method of mutual tank reversal realizes continuous injection to ensure the demand for coal injection in the blast furnace. The lower part of the pulverized coal bunker is connected to the parallel injection tanks through pipelines. After the injection cycle of the parallel-arranged injection tanks is completed, the pressure relief cycle is executed to discharge the high-pressure gas in the tank into the pulverized coal bunker. The pressure relief gas entering the pulverized coal bunker is then discharged after passing through the bag dust collector on the bunker top, and the collected pulverized coal returns to the pulverized coal bunker again. Production practice shows that during the production process of pressure relief of the injection tank, a large amount of high-pressure gas is discharged into the pulverized coal bunker. When the pressure control of the pulverized coal bunker is not appropriate, more serious production problems will occur. If the pressure of the pulverized coal bin is a relatively high positive pressure, the pulverized coal produced by the pulverizing system cannot flow smoothly by gravity from the pulverized coal collector ash bin through the pipeline into the pulverized coal bin, and the pulverized coal will accumulate in the pipeline. In serious cases, the pulverized coal will overflow from the pulverized coal vibrating screen and the flange connection of the pipeline, which will not only affect the normal production of the system, but also cause greater environmental pollution; if the pressure of the pulverized coal bin is a relatively low negative pressure, the ambient air will enter the pulverized coal bin from the pulverized coal vibrating screen and the flange connection of the pipeline, causing the oxygen content of the pulverized coal bin to exceed the standard, destroying the inert environment required by the pulverized coal bin, and thus affecting the normal production of the system. Therefore, the pressure control of the pulverized coal bin is crucial for the blast furnace coal injection system to achieve stable production.

[0004] In the existing public patent reports, "Blast Furnace Coal Injection Pulverizing System with Coal Powder Bin Negative Pressure Device" (202321635870.7) discloses a coal powder bin negative pressure device, but does not involve how to control the coal powder bin pressure and automatic control during the pressure relief process of the injection tank. At the same time, the patent uses the main exhaust fan of the pulverizing system to extract and discharge the coal powder bin gas, which will cause the pulverizing and injection systems to restrain each other in production and cannot be independent of each other, which brings difficulties to the maintenance of the pulverizing system. Summary of the invention

[0005] In view of this, an object of the present invention is to provide a method and device for controlling the pressure of a pulverized coal bin in a blast furnace coal injection system, so as to overcome the above-mentioned deficiencies of the prior art.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a method for controlling the pressure of a pulverized coal bunker of a blast furnace coal injection system, using a pulverized coal bunker pressure control device of a blast furnace coal injection system, the device comprising a pulverized coal bunker, and two or more injection tanks connected to the pulverized coal bunker through a pressure relief main pipeline, respectively, the injection tank and the pulverized coal bunker are provided with pressure gauges, the pulverized coal bunker is provided with a bunker top dust collector, and the bunker top dust collector is provided with a dispersing fan; each pressure relief main pipeline is provided with a first pressure relief branch pipe and a second pressure relief branch pipe, and the first pressure relief branch pipe and the second pressure relief branch pipe are respectively provided with a flow regulating valve and a first pneumatic shut-off valve; comprising the following steps:

[0007] S1, respectively establish the injection tank pressure relief control model and the pulverized coal bin pressure control model in the control program;

[0008] S2, during the pressure relief process of the spray tank, when the pressure PT of the spray tank is greater than 300 kPa, the opening K of the flow regulating valve on the first pressure relief branch pipe is firstly linearly adjusted. PN =K PNi +αU P , gradually open the flow control valve opening;

[0009] S21, when the pulverized coal bin pressure PT C -PT CSet <ΔP C When , the opening of the flow regulating valve of the first pressure relief branch pipe continues to be linearly adjusted;

[0010] S22, when the pulverized coal bin pressure PT C -PT CSet =ΔP C When the pressure relief pipeline flow control valve opening is maintained at K PN constant;

[0011] S23, when the pulverized coal bin pressure PT C -PT CSet >ΔP C When the opening degree K of the pressure relief pipeline flow regulating valve is linearly adjusted PN =K PNi +αU P , gradually reduce the flow control valve opening until the pulverized coal bin pressure PT C -PT CSet ≤ΔP C When the pressure relief pipeline flow control valve opening is maintained at K PN Unchanged, pulverized coal bunker pressure PT C Control completed;

[0012] S3, when the pressure of the spray tank PT≤300kPa, adjust the opening K of the flow regulating valve of the first pressure relief branch pipe PN =100%, and at the same time, open the first pneumatic shut-off valve of the second pressure relief branch pipe;

[0013] S31, when the pulverized coal bin pressure PT C -PT CSet >ΔP C When the frequency converter frequency F of the fan is linearly adjusted X =F XSet +βU F , gradually increase the capacity of the exhaust fan;

[0014] S32, when the pulverized coal bin pressure PT C -PT CSet =ΔP C When the fan frequency converter frequency F is maintained X constant;

[0015] S33, when the pulverized coal bin pressure PT C -PT CSet <ΔP C When the fan frequency is maintained at the initial setting value F XSet Unchanged, pulverized coal bunker pressure PT C Control completed;

[0016] S4, when the pressure of the spray tank PT = 0, the pressure relief cycle of the spray tank ends. When the spray tank performs the coal loading-pressurization-waiting-spraying cycle in sequence, the frequency of the frequency converter of the venting fan is adjusted to the set value F XSet , pulverized coal bunker pressure PT C Control completed;

[0017] Among them, PT, PT C are the measured pressure values ​​of the injection tank and the pulverized coal bin respectively measured by the pressure gauge; PT CSet is the pressure setting value of the pulverized coal bin; K PN K is the measured value of the flow control valve opening; PNi is the initial value of the flow control valve opening; F X 、F XSet are the measured value and set value of the frequency converter of the exhaust fan respectively; α is the adjustment coefficient of the flow control valve opening, and β is the adjustment coefficient of the exhaust fan frequency converter. Both are set manually according to the actual working conditions, and the value range is an integer from 0 to 100; U P , U F They are the smallest regulating units of the flow control valve and the exhaust fan inverter respectively.

[0018] Optional, pulverized coal bunker pressure setting value PT CSet, manually input the setting on the control system screen, and the value range is -10kPa~0kPa.

[0019] Optionally, the difference between the measured pressure of the pulverized coal bunker and the set pressure ΔP C , manually input the setting on the control system screen, and the value range is 0kPa~1kPa.

[0020] Optional, the fan inverter frequency setting value F XSet , manually input the setting on the control system screen, and the value range is 0HZ~50HZ.

[0021] A pulverized coal bunker pressure control device for a blast furnace coal injection system comprises a pulverized coal bunker and two or more injection tanks respectively connected to the pulverized coal bunker through a pressure relief main pipeline, each injection tank is provided with a pressure gauge, and a bunker top dust collector is provided on the pulverized coal bunker, and the bunker top dust collector is also provided with a variable frequency dispersion fan.

[0022] Optionally, each main pressure relief pipeline is provided with a first pressure relief branch pipe and a second pressure relief branch pipe, and the first pressure relief branch pipe and the second pressure relief branch pipe are respectively provided with a flow regulating valve and a first pneumatic shut-off valve.

[0023] The beneficial effects of the present invention are:

[0024] 1) A method and device for controlling the pressure of a pulverized coal bunker in a blast furnace coal injection system of the present invention can accurately control the pressure of the pulverized coal bunker and significantly improve the safety and stability of the production of the blast furnace coal injection system;

[0025] 2) The present invention provides a method and device for controlling the pressure of a pulverized coal bunker in a blast furnace coal injection system, which greatly improves the automation control level of the system and reduces the workload of operators;

[0026] 3) A method and device for controlling the pressure of a pulverized coal bunker in a blast furnace coal injection system of the present invention can realize independent production of a pulverizing system and an injection system without affecting each other;

[0027] 4) The pulverized coal bin pressure control method and device of the blast furnace coal injection system of the present invention can be used to transform the existing blast furnace coal injection system and has a wide range of applications.

[0028] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0030] Figure 1 It is a schematic structural diagram of a pulverized coal bin pressure control device of a blast furnace coal injection system of the present invention.

[0031] Figure numerals: vent fan 1, A spray tank pressure relief main pipeline 2, A spray tank second pressure relief branch 3, first pneumatic shut-off valve 4, A spray tank pressure gauge 5, A spray tank 6, A spray tank first pressure relief branch 7, first flow regulating valve 8, pulverized coal bin 9, B spray tank first pressure relief branch 10, second flow regulating valve 11, B spray tank 12, B spray tank pressure gauge 13, second pneumatic shut-off valve 14, B spray tank second pressure relief branch 15, B spray tank pressure relief main pipeline 16, pulverized coal bin pressure gauge 17, silo top dust collector 18. DETAILED DESCRIPTION

[0032] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0033] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0034] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0035] See also Figure 1, which is a pulverized coal bunker pressure control device for a blast furnace coal injection system, comprising a pulverized coal bunker 9, and an A-blowing tank 6 and a B-blowing tank 12 connected to the pulverized coal bunker through an A-blowing tank pressure relief main pipeline 2 and a B-blowing tank pressure relief main pipeline 16, respectively;

[0036] The A spray tank pressure relief main pipeline 2 is provided with an A spray tank second pressure relief branch pipe 3 and an A spray tank first pressure relief branch pipe 7, and the A spray tank second pressure relief branch pipe 3 and the A spray tank first pressure relief branch pipe 7 are respectively provided with a first pneumatic shut-off valve 4 and a first flow regulating valve 8;

[0037] The B spray tank pressure relief main pipeline 16 is provided with a B spray tank second pressure relief branch pipe 15 and a B spray tank first pressure relief branch pipe 10, and the B spray tank second pressure relief branch pipe 15 and the B spray tank first pressure relief branch pipe 10 are respectively provided with a second pneumatic shut-off valve 14 and a second flow regulating valve 11;

[0038] The A spray tank 6 and the B spray tank 12 are provided with an A spray tank pressure gauge and a B spray tank pressure gauge respectively, the pulverized coal bin 9 is provided with a pulverized coal bin pressure gauge 17, and the pulverized coal bin 9 is also provided with a bin top dust collector 18, and the bin top dust collector 18 is also provided with a variable frequency dispersion fan 1.

[0039] A method for controlling the pressure of a pulverized coal bunker of a blast furnace coal injection system, using the pulverized coal bunker pressure control device of the blast furnace coal injection system as described above, comprises the following steps:

[0040] S1, respectively establish the injection tank pressure relief control model and the pulverized coal bin pressure control model in the control program;

[0041] S2, during the pressure relief process of the spray tank, when the pressure of the spray tank PT A or PT B When the pressure is higher than 300 kPa, first adjust the opening K of the flow control valve on the first pressure relief branch pipe linearly. PN =K PNi +αU P , gradually open the flow control valve opening;

[0042] S21, when the pressure of coal powder bin 9 PT C -PT CSet <ΔP C When , the opening of the flow regulating valve of the first pressure relief branch pipe continues to be linearly adjusted;

[0043] S22, when the pressure of coal powder bin 9 PT C -PT CSet =ΔP C When the pressure relief pipeline flow control valve opening is maintained at K PN constant;

[0044] S23, when the pressure of coal powder bin 9 PT C-PT CSet >ΔP C When the opening degree K of the pressure relief pipeline flow regulating valve is linearly adjusted PN =K PNi +αU P , gradually reduce the flow control valve opening until the pulverized coal bin pressure PT C -PT CSet ≤ΔP C When the pressure relief pipeline flow control valve opening is maintained at K PN Unchanged, pulverized coal bunker pressure PT C Control completed;

[0045] S3, when the spray tank pressure PT A or PT B When the pressure is ≤300kPa, adjust the opening degree K of the flow regulating valve of the first pressure relief branch pipe PN =100%, and at the same time, open the first pneumatic shut-off valve of the second pressure relief branch pipe;

[0046] S31, when the pressure of coal powder bin 9 PT C -PT CSet >ΔP C When the frequency F of the inverter of the exhaust fan 1 is linearly adjusted X =F XSet +βU F , gradually increase the capacity of the exhaust fan 1;

[0047] S32, when the pressure of coal powder bin 9 PT C -PT CSet =ΔP C When the fan frequency converter frequency F is maintained X constant;

[0048] S33, when the pressure of coal powder bin 9 PT C -PT CSet <ΔP C When the frequency of the fan 1 inverter is maintained at the initial setting value F XSet Unchanged, coal powder bunker 9 pressure PT C Control completed;

[0049] S4, when the spray tank pressure PT A or PT B = 0, the pressure relief cycle of the spray tank ends. When the spray tank performs the coal loading-pressurization-waiting-spraying cycle in sequence, the frequency of the inverter of the dispersing fan 1 is adjusted to the set value F XSet , pulverized coal bunker 9 pressure PT C Control completed;

[0050] Among them, PT A PT B PTC are respectively the measured pressure values ​​of the A injection tank 6, the B injection tank 12 and the pulverized coal bin 9 measured by the pressure gauge; PT CSet K is the pressure setting value of the pulverized coal bin 9; PN K is the measured value of the flow control valve opening; PNi is the initial value of the flow control valve opening; F X 、F XSet are the measured value and set value of the frequency converter of the exhaust fan 1 respectively; α is the adjustment coefficient of the flow control valve opening, and β is the adjustment coefficient of the frequency converter of the exhaust fan 1. Both are set manually according to the actual working conditions, and the value range is an integer from 0 to 100; U P , U F They are the minimum regulating units of the flow control valve and the frequency converter of the exhaust fan 1 respectively.

[0051] In this embodiment, the pressure setting value PT of the pulverized coal bin 9 is CSet , manually input the setting on the control system screen, and the value range is -10kPa~0kPa.

[0052] In this embodiment, the difference between the measured pressure of the pulverized coal bin 9 and the set pressure ΔP C , manually input the setting on the control system screen, and the value range is 0kPa~1kPa.

[0053] In this embodiment, the frequency setting value F of the frequency converter of the fan 1 is XSet , manually input the setting on the control system screen, and the value range is 0HZ~50HZ.

[0054] Specific embodiment 1,

[0055] Firstly, the pressure relief control model of the blowing tank and the pressure control model of the pulverized coal bin were established. Then, the pressure of the pulverized coal bin was adjusted by the above two models during the pressure relief cycle of the blowing tank to achieve accurate control of the pressure of the pulverized coal bin in a slightly negative pressure state. The pressure relief control model of the blowing tank and the pressure control model of the pulverized coal bin were used to control the PT C -PT CSet ≤ΔP C kPa is the optimal target, and the specific implementation method is as follows:

[0056] Step 1: End the spraying at spray tank A 6. During the pressure relief cycle, when the pressure of spray tank A PT A When the initial value is 1000 kPa, first adjust the opening degree K of the first flow regulating valve 8 of the first pressure relief branch pipe 7 of the spray tank A linearly. PN , gradually open the flow regulating valve 8. If the measured value of the pulverized coal bin pressure PT C -8kPa, coal powder bunker set pressure PT CSetWhen it is -5kPa, at this time -8-(-5)=-3(kPa)<1(kPa), the first flow regulating valve 8 of the first pressure relief branch pipe 7 is linearly adjusted according to the program, and the opening degree K of the flow regulating valve 8 is gradually opened. PN ; If the measured value of the pulverized coal bin pressure PT C -4kPa, coal powder bunker set pressure PT CSet When it is -5kPa, at this time -4-(-5) = 1(kPa), the opening degree K of the first flow regulating valve 8 of the first pressure relief branch pipe 7 is maintained. PN If the measured value of the pulverized coal bunker pressure PT C -3kPa, coal powder bunker set pressure PT CSet When it is -5kPa, at this time -3-(-5)=2(kPa)>1(kPa), the opening degree K of the first flow regulating valve 8 of the first pressure relief branch pipe 7 is linearly adjusted. PN , gradually close the flow control valve 8 opening K PN Until the measured value of the pulverized coal bunker pressure PT C ≤-4kPa, the opening degree K of the first flow regulating valve 8 of the first pressure relief branch pipe 7 is maintained PN constant.

[0057] Step 2: When the pressure of the spray tank is PT A When the pressure drops to ≤300 kPa, adjust the opening degree K of the first flow regulating valve 8 of the first pressure relief branch pipe 7. PN =100%, and at the same time, open the first pneumatic shut-off valve 7 of the second pressure relief branch. If the measured value of the coal powder bin pressure PT C -3kPa, coal powder bunker set pressure PT CSet When it is -5kPa, at this time -3-(-5)=2(kPa)>1(kPa), the frequency F of the inverter of the fan 1 is linearly increased. X , gradually increase the exhaust capacity of the exhaust fan 1; if the measured value of the pulverized coal bin pressure PT C -4kPa, coal powder bunker set pressure PT CSet When it is -5kPa, -4-(-5)=1(kPa), then the frequency of the inverter of the fan 1 is kept at F. X If the measured value of the pulverized coal bunker pressure PT C -8kPa, coal powder bunker set pressure PT CSet When it is -5kPa, at this time -8-(-5)=-3(kPa)<1(kPa), then maintain the initial setting value F of the frequency converter of the fan. XSet Unchanged, pulverized coal bunker pressure PT C Control completed.

[0058] Step 3: When the pressure of spray tank A is PT A=0, the pressure relief cycle of A spray tank ends. When A spray tank performs the coal loading-pressurization-waiting-spraying cycle in sequence, adjust the frequency of the inverter of the dispersing fan 1 to the set value F XSet , pulverized coal bunker pressure PT C Control completed.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A method for controlling the pressure of a pulverized coal bunker in a blast furnace coal injection system, characterized in that: A pulverized coal bunker pressure control device for a blast furnace coal injection system is used, the device comprises a pulverized coal bunker, and two or more injection tanks connected to the pulverized coal bunker through a pressure relief main pipeline, pressure gauges are provided on the injection tanks and the pulverized coal bunker, a bunker top dust collector is provided on the pulverized coal bunker, and the bunker top dust collector is provided with a dispersing fan; a first pressure relief branch pipe and a second pressure relief branch pipe are provided on each pressure relief main pipeline, and a flow regulating valve and a first pneumatic shut-off valve are provided on the first pressure relief branch pipe and the second pressure relief branch pipe, respectively; the following steps are included: S1, respectively establish the injection tank pressure relief control model and the pulverized coal bin pressure control model in the control program; S2, during the pressure relief process of the spray tank, when the pressure PT of the spray tank is greater than 300 kPa, the opening K of the flow regulating valve on the first pressure relief branch pipe is firstly linearly adjusted. PN =K PNi +αU P , gradually open the flow control valve opening; S21, when the pulverized coal bin pressure PT C -PT CSet <ΔP C When , the opening of the flow regulating valve of the first pressure relief branch pipe continues to be linearly adjusted; S22, when the pulverized coal bin pressure PT C -PT CSet =ΔP C When the pressure relief pipeline flow control valve opening is maintained at K PN constant; S23, when the pulverized coal bin pressure PT C -PT CSet >ΔP C When the opening degree K of the pressure relief pipeline flow regulating valve is linearly adjusted PN =K PNi +αU P , gradually reduce the flow control valve opening until the pulverized coal bin pressure PT C -PT CSet ≤ΔP C When the pressure relief pipeline flow control valve opening is maintained at K PN Unchanged, pulverized coal bunker pressure PT C Control completed; S3, when the pressure of the spray tank PT≤300kPa, adjust the opening K of the flow regulating valve of the first pressure relief branch pipe PN =100%, and at the same time, open the first pneumatic shut-off valve of the second pressure relief branch pipe; S31, when the pulverized coal bin pressure PT C -PT CSet >ΔP C When the frequency converter frequency F of the fan is linearly adjusted X =F XSet +βU F , gradually increase the capacity of the exhaust fan; S32, when the pulverized coal bin pressure PT C -PT CSet =ΔP C When the fan frequency converter frequency F is maintained X constant; S33, when the pulverized coal bin pressure PT C -PT CSet <ΔP C When the fan frequency is maintained at the initial setting value F XSet Unchanged, pulverized coal bunker pressure PT C Control completed; S4, when the pressure of the spray tank PT = 0, the pressure relief cycle of the spray tank ends. When the spray tank performs the coal loading-pressurization-waiting-spraying cycle in sequence, the frequency of the frequency converter of the venting fan is adjusted to the set value F XSet , pulverized coal bunker pressure PT C Control completed; Among them, PT, PT C are the measured pressure values ​​of the injection tank and the pulverized coal bin respectively measured by the pressure gauge; PT CSet is the pressure setting value of the pulverized coal bin; K PN K is the measured value of the flow control valve opening; PNi is the initial value of the flow control valve opening; F X 、F XSet are the measured value and set value of the frequency converter of the exhaust fan respectively; α is the adjustment coefficient of the flow control valve opening, and β is the adjustment coefficient of the exhaust fan frequency converter. Both are set manually according to the actual working conditions, and the value range is an integer from 0 to 100; U P , U F They are the smallest regulating units of the flow control valve and the exhaust fan inverter respectively.

2. The method for controlling the pressure of a pulverized coal bunker in a blast furnace coal injection system according to claim 1, characterized in that: Pressure setting value PT of pulverized coal bunker CSet , manually input the setting on the control system screen, and the value range is -10kPa~0kPa.

3. The method for controlling the pressure of a pulverized coal bunker in a blast furnace coal injection system according to claim 1, characterized in that: The difference between the measured pressure and the set pressure of the pulverized coal bunker ΔP C , manually input the setting on the control system screen, and the value range is 0kPa~1kPa.

4. The method for controlling the pressure of a pulverized coal bunker in a blast furnace coal injection system according to claim 1, characterized in that: Dissipation fan inverter frequency setting value F XSet , manually input the setting on the control system screen, and the value range is 0HZ~50HZ.

5. A pulverized coal bunker pressure control device for a blast furnace coal injection system, characterized in that: It includes a pulverized coal bin and more than two spray tanks connected to the pulverized coal bin through a main pressure relief pipeline. Each spray tank is provided with a pressure gauge. The pulverized coal bin is provided with a bin top dust collector, which is also provided with a variable frequency dispersion fan.

6. The pulverized coal bunker pressure control device of a blast furnace coal injection system according to claim 5, characterized in that: A first pressure relief branch pipe and a second pressure relief branch pipe are arranged on each main pressure relief pipeline, and a flow regulating valve and a first pneumatic cut-off valve are arranged on the first pressure relief branch pipe and the second pressure relief branch pipe respectively.

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