Automatic pollution discharge control method and device for injection main pipe 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 an automatic blowdown control method and device for an injection main pipe of a blast furnace coal injection system. The method mainly comprises the following steps: establishing a pulverized coal main pipe filter blowback control model, judging the pressure deviation degree of a conveying tank in a blowing sub-process, and dynamically adjusting the blowback gas quantity of the filter in a pressure relief sub-process to finish online automatic pollution discharge of the filter. The method has the advantages that on the premise that the production requirement of continuous injection of the system is guaranteed, on-line automatic pollution discharge of the pulverized coal main pipe can be achieved, 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 an automatic sewage discharge control method and device for a blast furnace coal injection system injection main pipe. Background Art

[0002] Coal injection in blast furnaces is an important technical measure to partially replace expensive and increasingly scarce coke with cheap pulverized coal, achieve structural energy conservation and improve economic benefits, and the continuous and stable injection of the coal injection system is an important guarantee for achieving the above-mentioned technical and economic effects.

[0003] At present, the blast furnace coal injection system generally adopts the parallel tank injection process. The system is equipped with at least two or more parallel-arranged injection tanks. Each injection tank works alternately according to the procedure of injection-pressure relief-coal loading-pressurization-waiting. The injection method of mutual tank reversal ensures continuous coal powder injection, thereby meeting the stable demand for coal powder injection in the blast furnace. In the actual production process, non-coal light debris such as broken wood chips and broken woven bags often appear in the coal powder ground by the coal mill, resulting in frequent production failures such as blockage of coal powder pipelines and blockage of coal powder spray guns.

[0004] In order to solve the above problems, the industry has carried out research on the filter equipment body and automatic filtering, which is a technical hotspot. At present, in production, a coal powder filter is generally set at the coal powder main pipe to intercept the non-coal light debris entrained in the coal powder at the coal powder filter to prevent the debris from further spreading to the coal powder main pipe or reaching the coal powder spray gun. Therefore, after the filter has been working for a period of time, it is necessary to clean up the debris intercepted by the filter in time. Generally, the coal powder filter is manually disassembled at regular intervals to clean up the light debris at the filter screen of the coal powder filter, such as the public patent "A Coal Powder Automatic Filtering Device" (201520920355.2), but this method still has the shortcomings of long cleaning time and high manpower consumption. In addition, coal powder is easy to leak during manual cleaning, and the leaked coal powder may also form a suspended dust cloud under certain conditions, posing a safety hazard to on-site operators. In order to solve the problems caused by manual timed cleaning, relevant researchers have proposed an online automatic cleaning device and control method, such as the public patent "Online automatic cleaning device and control method for blast furnace coal injection system" (202111632333.2). This method uses automatic control of the pressure difference before and after the filter. Although it solves the problem of manual timed cleaning, the filter and the spare filter are installed in series on the same main injection pipeline, which cannot meet the production requirements of continuous coal powder injection during automatic cleaning. In order to solve the problem that the above-mentioned filters cannot be continuously sprayed with coal powder when installed in series, the public patent "An automatic clearing device for coal injection pipeline filter" (202222829155.9) proposes to set two coal powder pipeline branches in parallel in the middle of the coal powder main pipe, and alternately work through the two coal powder pipeline branches to meet the production requirements of continuous coal powder injection during automatic cleaning. However, this solution divides the coal powder pipeline into two and adds elbows to change the flow direction of coal powder many times. In the gas-solid two-phase flow, it will not only increase the resistance loss and energy consumption during the transportation process, but also aggravate the wear of the elbows and reduce the service life of the equipment. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a method and device for automatically discharging pollutants from the injection main pipe of 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 automatically discharging sewage from a blast furnace coal injection system injection main pipe, using an automatic discharging sewage control device for a blast furnace coal injection system injection main pipe, the device comprising a pulverized coal bin, a pulverized coal distributor, and two or more injection tanks arranged between the pulverized coal bin and the pulverized coal distributor, each injection tank having a pressure gauge and an electronic scale, and a first pulverized coal main pipe shut-off valve, an air replenisher, a pulverized coal filter and a second pulverized coal main pipe shut-off valve are respectively arranged on the pipeline between the injection tank and the pulverized coal distributor, the air replenisher is externally connected to an air replenishment valve, and the pulverized coal filter is externally connected to a back-blowing valve, comprising the following steps:

[0007] S1, establish the back-flushing control model of the pulverized coal main filter in the control program;

[0008] S2, during the pulverized coal injection process, the measured value of the conveying tank pressure is compared with the set value at the set conveying rate;

[0009] S21, during the blowing sub-process of any blowing tank, when the tank pressure P X -P Set-N ≥ΔP Set When, spray again Second;

[0010] S22, after the spray tank finishes the spray sub-process and enters the pressure relief sub-process with a delay of T2 seconds, first close the second shut-off valve of the pulverized coal main pipe corresponding to the spray tank, and then open the back-blowing valve and the air supply valve corresponding to the spray tank in sequence to start back-blowing the pulverized coal filter;

[0011] S3, then in the pressure relief sub-process, dynamically adjust the filter back-blowing gas volume to achieve online automatic sewage discharge in the pulverized coal main;

[0012] S31, during the pressure relief sub-process of the spray tank, after T3 seconds of back-blowing, the corresponding air supply valve and back-blowing valve of the spray tank are closed in sequence;

[0013] S32, then open the second shut-off valve of the pulverized coal main pipe corresponding to the injection tank to end the back-flushing of the pulverized coal filter;

[0014] Among them, P X P is the actual pressure value measured by the pressure gauge of the spray tank; Set-N The pressure setting value of the spray tank corresponding to different set delivery rates is manually input and set on the control system screen; W X V is the actual weight value measured by the electronic scale of the spray tank; Set-N It is the set value of the delivery rate of the spray tank, which is manually input and set on the control system screen; T1 is the spraying time after the tank pressure deviation is detected.

[0015] Furthermore, the control model includes matching the delivery rate with the tank pressure of the spray tank, and constructing the following table database through on-site debugging.

[0016]

[0017]

[0018] Furthermore, the difference between the measured tank pressure and the set value ΔP Set , manually input the setting on the control system screen, the value range is 20kPa~100kPa.

[0019] Furthermore, the weight setting value of the coal at the bottom of the injection tank is W Set, manually input the setting on the control system screen, the normal value range is 1t~3t, and the value range in emergency is (W X -1)t.

[0020] Furthermore, the delay setting time T2 is manually input and set on the control system screen, and the value range is 10s to 120s.

[0021] Furthermore, the backwash time setting value T3 of the pulverized coal filter is manually input and set on the control system screen, and the value range is 0s to 600s.

[0022] An automatic sewage discharge control device for an injection main pipe of a blast furnace coal injection system comprises a pulverized coal bin, a pulverized coal distributor, and more than two injection tanks arranged between the pulverized coal bin and the pulverized coal distributor. The bottom outlet of each injection tank is connected to the pulverized coal distributor through a pulverized coal main pipe. The pulverized coal main pipe is provided with a pulverized coal filter. The pulverized coal filter is also externally connected to a sewage discharge pipe. After the sewage discharge pipes of each injection tank are merged, a collection barrel of a bag dust collector is connected.

[0023] Furthermore, each injection tank is equipped with a pressure gauge and an electronic scale, and the pipeline between the injection tank and the pulverized coal distributor is also provided with a first shut-off valve of the pulverized coal main pipe, and a second shut-off valve of the air replenisher and the pulverized coal main pipe.

[0024] Furthermore, a back-blowing valve is provided on the pulverized coal filter, and an air supply valve is provided on the air supply device.

[0025] The beneficial effects of the present invention are as follows: the present invention can realize online automatic sewage discharge of the injection main pipe while ensuring the production requirements of continuous injection of the system; it solves the problem of elbow wear in the prior art solution and effectively extends the service life of the equipment; it greatly improves the automation control level of the system and reduces the workload of the operator; it can be used to transform the existing blast furnace coal injection system and has a wide range of applications.

[0026] 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

[0027] 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:

[0028] Figure 1 It is a schematic diagram of the automatic sewage discharge control device of the injection main pipe of the blast furnace coal injection system of the present invention.

[0029] Figure numerals: pulverized coal bin 1, collecting bucket 2, first pressure gauge 3, A blowing tank 4, A blowing tank electronic scale 5, A blowing tank air supply valve 6, A blowing tank pulverized coal main pipe first cut-off valve 7, first air supply device 8, A blowing tank back-blowing valve 9, first pulverized coal filter 10, A blowing tank pulverized coal main pipe second cut-off valve 11, B blowing tank air supply valve 12, B blowing tank electronic scale 13, second pressure gauge 14, B blowing tank 15, B blowing tank pulverized coal main pipe first cut-off valve 16, second air supply device 17, B blowing tank back-blowing valve 18, second pulverized coal filter 19, B blowing tank pulverized coal main pipe second cut-off valve 20, pulverized coal distributor 21. DETAILED DESCRIPTION

[0030] 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.

[0031] 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.

[0032] 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.

[0033] See also Figure 1, is an automatic sewage discharge control device for the injection pipe of the blast furnace coal injection system, comprising a pulverized coal bin 1, a pulverized coal distributor 21, and an A injection tank 4 and a B injection tank 15 arranged between the pulverized coal bin 1 and the pulverized coal distributor 21, the bottom outlet of each injection tank is connected to the pulverized coal distributor 21 through a pulverized coal pipe, the pulverized coal pipe is provided with a pulverized coal filter, and the pulverized coal filter is also externally connected to a sewage pipe, and the sewage pipes of each injection tank are connected to a collection bucket 2 of a bag dust collector after merging.

[0034] The A spray tank 4 is provided with a first pressure gauge 3 and an A spray tank electronic scale 5. The pipeline between the A spray tank 4 and the pulverized coal distributor 21 is also provided with a first shut-off valve 7 for the pulverized coal main pipe of the A spray tank, a first air replenisher 8, a first pulverized coal filter 10 and a second shut-off valve 11 for the pulverized coal main pipe of the A spray tank; the first pulverized coal filter 10 is provided with an A spray tank back-blowing valve 9, and the first air replenisher 8 is provided with an A spray tank air replenishing valve 6;

[0035] The B blowing tank 15 is provided with a second pressure gauge 14 and a B blowing tank electronic scale 13; the pipeline between the B blowing tank 15 and the pulverized coal distributor 21 is also provided with a first shut-off valve 16 for the pulverized coal main line of the B blowing tank, a second air replenisher 17, a second pulverized coal filter 19 and a second shut-off valve 20 for the pulverized coal main line of the B blowing tank; the second pulverized coal filter 19 is provided with a B blowing tank back-blowing valve 18, and the second air replenisher 17 is provided with a B blowing tank air replenishment valve 12.

[0036] The present invention provides a method for automatically discharging pollutants from a blast furnace coal injection system injection main pipe, and further comprises the following steps:

[0037] S1, establish the back-flushing control model of the pulverized coal main filter in the control program;

[0038] S2, during the pulverized coal injection process, the measured value of the conveying tank pressure is compared with the set value at the set conveying rate;

[0039] S21, during the blowing sub-process of any blowing tank, when the tank pressure P X -P Set-N ≥ΔP Set When, spray again Second;

[0040] S22, after the spray tank finishes the spray sub-process and enters the pressure relief sub-process with a delay of T2 seconds, first close the second shut-off valve of the pulverized coal main pipe corresponding to the spray tank, and then open the back-blowing valve and the air supply valve corresponding to the spray tank in sequence to start back-blowing the pulverized coal filter;

[0041] S3, then in the pressure relief sub-process, dynamically adjust the filter back-blowing gas volume to achieve online automatic sewage discharge in the pulverized coal main;

[0042] S31, during the pressure relief sub-process of the spray tank, after T3 seconds of back-blowing, the corresponding air supply valve and back-blowing valve of the spray tank are closed in sequence;

[0043] S32, then open the second shut-off valve of the pulverized coal main pipe corresponding to the injection tank to end the back-flushing of the pulverized coal filter;

[0044] Among them, P X P is the actual pressure value measured by the pressure gauge of the spray tank; Set-N The pressure setting value of the spray tank corresponding to different set delivery rates is manually input and set on the control system screen; W X V is the actual weight value measured by the electronic scale of the spray tank; Set-N It is the set value of the delivery rate of the spray tank, which is manually input and set on the control system screen; T1 is the spraying time after the tank pressure deviation is detected.

[0045] In this embodiment, the control model includes matching the delivery rate with the tank pressure of the spray tank, and constructing the following table database through on-site debugging.

[0046] Serial number Rate setting value (t / h) Tank pressure setting value (kPa) 1 <![CDATA[V Set-1 ]]> <![CDATA[P Set-1 ]]> 2 <![CDATA[V Set-2 ]]> <![CDATA[P Set-2 ]]> …… …… …… N <![CDATA[V Set-N ]]> <![CDATA[P Set-N ]]>

[0047] In this embodiment, the difference between the measured tank pressure and the set value ΔP Set , manually input the setting on the control system screen, the value range is 20kPa~100kPa.

[0048] In this embodiment, the weight setting value of the coal at the bottom of the injection tank is W Set , manually input the setting on the control system screen, the normal value range is 1t~3t, and the value range in emergency is (W X -1)t.

[0049] In this embodiment, the delay setting time T2 is manually input and set on the control system screen, and the value range is 10s to 120s.

[0050] In this embodiment, the back-flushing time setting value T3 of the pulverized coal filter is manually input and set on the control system screen, and the value range is 0s to 600s.

[0051] Specific embodiment 1,

[0052] A certain iron and steel plant has a coal injection system, which consists of a coal powder bin and two injection tanks, as well as supporting valves, pipelines, etc. First, a back-blowing control model for the filter in the coal powder main pipe is established, and in the coal powder injection sub-process, the measured value of the conveying tank pressure is compared with the set value at the set conveying rate. Then, in the pressure relief sub-process, the filter back-blowing gas volume is dynamically adjusted to realize the online automatic sewage discharge of the coal powder main pipe.

[0053] The specific implementation method is as follows: During the blowing process of the A blowing tank, the blowing tank conveying rate V Set-5 =30t / h, tank pressure setting value P Set-5 =900kPa, tank pressure measured value P X =980kPa, actual measured value of the spray tank weight W X =15t, the setting value of coal weight at the bottom of the injection tank is W Set =3t. When P X -P Set-1 =80≥50kPa, the system continues to spray T1=(15-3) / 30=0.4(h)=1440(s), and then the A spray tank ends the spray sub-process and enters the pressure relief sub-process. After the pressure relief sub-process delay T2=60s, first close the second shut-off valve of the pulverized coal main pipe corresponding to the A spray tank, and then open the back-blowing valve and air supply valve corresponding to the A spray tank in sequence to start the back-blowing operation of the pulverized coal filter.

[0054] During the pressure relief sub-process of the A spray tank, after back-blowing T2=180s, the air supply valve and back-blowing valve corresponding to the spray tank are closed in sequence, and then the second shut-off valve of the pulverized coal main pipe corresponding to the spray tank is opened to end the back-blowing of the pulverized coal filter.

[0055] 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 automatically discharging waste from a blast furnace coal injection system injection main pipe, characterized in that: The automatic sewage discharge control device of the injection main pipe of the blast furnace coal injection system is applied, which includes a pulverized coal bin, a pulverized coal distributor, and more than two injection tanks arranged between the pulverized coal bin and the pulverized coal distributor. Each injection tank is equipped with a pressure gauge and an electronic scale. The pipeline between the injection tank and the pulverized coal distributor is also respectively provided with a first shut-off valve of the pulverized coal main pipe, an air replenisher, a pulverized coal filter and a second shut-off valve of the pulverized coal main pipe. The air replenisher is externally connected to an air replenishment valve, and the pulverized coal filter is externally connected to a back-blowing valve. The following steps are included: S1, establish the back-flushing control model of the pulverized coal main filter in the control program; S2, during the pulverized coal injection process, the measured value of the conveying tank pressure is compared with the set value at the set conveying rate; S21, during the blowing sub-process of any blowing tank, when the tank pressure P X -P Set-N ≥ΔP Set When, spray again Second; S22, after the spray tank finishes the spray sub-process and enters the pressure relief sub-process with a delay of T2 seconds, first close the second shut-off valve of the pulverized coal main pipe corresponding to the spray tank, and then open the back-blowing valve and the air supply valve corresponding to the spray tank in sequence to start back-blowing the pulverized coal filter; S3, then in the pressure relief sub-process, dynamically adjust the filter back-blowing gas volume to achieve online automatic sewage discharge in the pulverized coal main; S31, during the pressure relief sub-process of the spray tank, after T3 seconds of back-blowing, the corresponding air supply valve and back-blowing valve of the spray tank are closed in sequence; S32, then open the second shut-off valve of the pulverized coal main pipe corresponding to the injection tank to end the back-flushing of the pulverized coal filter; Among them, P X P is the actual pressure value measured by the pressure gauge of the spray tank; Set-N The pressure setting value of the spray tank corresponding to different set delivery rates is manually input and set on the control system screen; W X V is the actual weight value measured by the electronic scale of the spray tank; Set-N It is the set value of the delivery rate of the spray tank, which is manually input and set on the control system screen; T1 is the spraying time after the tank pressure deviation is detected.

2. The method for automatic sewage discharge control of the injection main pipe of the blast furnace coal injection system according to claim 1 is characterized in that: The control model includes matching the delivery rate with the tank pressure of the spray tank, and building a database through on-site debugging, that is, the rate setting value is V Set-1 、V Set-2 …V Set-N , unit t / h; the corresponding tank pressure setting value is P Set-1 , P Set-2 …P Set-N , unit: kPa.

3. The method for automatic sewage discharge control of the injection main pipe of the blast furnace coal injection system according to claim 1, characterized in that: The difference between the measured tank pressure and the set value ΔP Set , manually input the setting on the control system screen, the value range is 20kPa~100kPa.

4. The method for automatic sewage discharge control of the injection main pipe of the blast furnace coal injection system according to claim 1 is characterized in that: Coal weight setting value W at the bottom of the injection tank Set , manually input the setting on the control system screen, the normal value range is 1t~3t, and the value range in emergency is (W X -1)t.

5. The method for automatic sewage discharge control of the injection main pipe of the blast furnace coal injection system according to claim 1, characterized in that: The delay setting time T2 is manually input and set on the control system screen, and the value range is 10s to 120s.

6. The method for automatic sewage discharge control of the injection main pipe of the blast furnace coal injection system according to claim 1, characterized in that: The pulverized coal filter backwash time setting value T3 is manually input and set on the control system screen, and the value range is 0s to 600s.

7. An automatic sewage discharge control device for the injection main pipe of a blast furnace coal injection system, characterized in that: It includes a coal powder bin, a coal powder distributor, and more than two blowing tanks arranged between the coal powder bin and the coal powder distributor. The bottom outlet of each blowing tank is connected to the coal powder distributor through a coal powder main pipe. The coal powder main pipe is provided with a coal powder filter. The coal powder filter is also externally connected to a sewage pipe. The sewage pipes of each blowing tank are connected to a collection bucket of a bag dust collector after merging.

8. The automatic sewage discharge control device for the injection main pipe of the blast furnace coal injection system according to claim 7 is characterized by: Each injection tank is equipped with a pressure gauge and an electronic scale. The pipeline between the injection tank and the pulverized coal distributor is also provided with a first shut-off valve of the pulverized coal main pipe, and a second shut-off valve of the air replenisher and the pulverized coal main pipe.

9. The automatic sewage discharge control device for the injection main pipe of the blast furnace coal injection system according to claim 8 is characterized by: A back-blowing valve is provided on the pulverized coal filter, and an air supply valve is provided on the air supply device.

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