A medium speed mill control method

Abstract

The application provides a medium-speed mill control method, wherein the method comprises the following steps: determining the operation state of a coal mill peripheral device, and performing a medium-speed mill start-up preparation; after the medium-speed mill start-up preparation is completed, a coal feeder is started, and the medium-speed mill start-up operation is completed; after a production plan is completed, an automatic mill stop operation is performed, then the main motor of the medium-speed mill is stopped, and finally a medium-speed mill post-stop operation is performed, the main motor of the medium-speed mill is stopped, and finally the medium-speed mill post-stop operation is performed, and the medium-speed mill stop operation is completed. The application solves the problems that the current coal injection pulverizing system is manually operated, the coal powder particle size control is uneven, the energy loss is large, and the misoperation rate is large. The application realizes the automatic control of the medium-speed mill and its attached devices and facilities by intelligently upgrading the coal injection pulverizing system and adjusting the coal pulverizing process parameters, improves the intelligent level of the coal pulverizing, and ensures the working efficiency of the coal pulverizing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coal grinding, in particular to a medium-speed mill control method. BACKGROUND

[0002] The commonly used equipment of the blast furnace coal injection pulverizing system is a medium-speed coal mill. The medium-speed coal mill is also a vertical coal mill, which is a drying and pulverizing two-in-one system and can realize coal powder preparation system with drying and grinding. At present, the whole process of the coal injection pulverizing system is manually controlled, and some process parameters and equipment control are set and operated by experience, which is easy to cause uneven control of coal powder particle size, large energy loss, and increased misoperation rate and other adverse effects.

[0003] Therefore, how to use an effective method to realize automatic control of the medium-speed mill and its affiliated equipment and facilities, achieve one-key operation of starting, grinding and stopping of the mill in the coal grinding process, improve the intelligent level of coal grinding, and ensure the work efficiency of coal grinding is a technical problem to be solved. SUMMARY

[0004] The purpose of the present application is to provide a medium-speed mill control method. The present application solves the problem that the coal injection pulverizing system is manually operated, resulting in uneven control of coal powder particle size, large energy loss, and high misoperation rate. The present application upgrades the intelligent level of the coal injection pulverizing system and adjusts the coal grinding process parameters, so that the medium-speed mill and its affiliated equipment and facilities realize automatic control, improve the intelligent level of coal grinding, and ensure the work efficiency of coal grinding.

[0005] Specifically, the present application adopts the following technical scheme:

[0006] The embodiment of the present application provides a medium-speed mill control method, which comprises: when a medium-speed mill executes a starting operation, first checking the running state of a coal grinding peripheral equipment, and after determining that the coal grinding peripheral equipment is running normally, executing a pre-starting operation before starting a powder exhaust fan;

[0007] After the pre-starting operation is completed and delayed for a first preset time, the powder exhaust fan and the waste gas fan are started in sequence, after the waste gas fan is started, a pre-bagging operation is executed before bagging, and after the pre-bagging operation is completed, a bagging operation is executed;

[0008] After the bagging operation is completed, a wind reversing operation is executed, when the outlet temperature of the medium-speed mill reaches 80 DEG C, the main motor of the medium-speed mill is started, and a blast furnace gas cut-off valve is opened, when the outlet temperature reaches 90 DEG C, a coal feeder is started, and the starting operation of the medium-speed mill is completed;

[0009] In the execution of the medium-speed mill stop grinding operation, the hot blast furnace stop burning operation is first executed, when the outlet temperature of the medium-speed mill is less than 50℃, the coal feeder is controlled to stop, the secondary air reversing operation is executed, when the variable frequency rotating speed of the powder exhaust fan is reduced to 450r / min, the inlet regulating valve of the waste gas fan is controlled to adjust to the preset valve position, then the main motor of the medium-speed mill is controlled to stop, finally the medium-speed mill stop grinding post-operation is executed, and the medium-speed mill stop grinding operation is completed.

[0010] In some embodiments of the present application, based on the foregoing scheme, the pre-starting operation of the powder exhaust fan before starting includes: controlling the damper regulating valve of the powder exhaust fan to adjust to 0%, controlling the outlet regulating valve of the air mixing furnace to adjust to 95%, controlling the diffusing regulating valve of the combustion air fan to adjust to 90%, controlling the inlet regulating valve of the waste gas fan to adjust to 0%, controlling the hot waste gas diffusing regulating valve to adjust to 95%, controlling the hot flue gas diffusing regulating valve to adjust to 95%, controlling the outlet shut-off valve of the heating furnace to close, controlling the inlet shut-off valve of the heating furnace to close, controlling the front shut-off valve of the waste gas fan to close, and controlling the variable frequency rotating speed of the powder exhaust fan to reach 450r / min.

[0011] In some embodiments of the present application, based on the foregoing scheme, the control of the powder exhaust fan and the waste gas fan starting in sequence includes: controlling the powder exhaust fan to execute the starting operation, and after the powder exhaust fan executes the starting operation, delaying for 10s, then controlling the waste gas fan to execute the starting operation, and after the waste gas fan executes the starting operation, delaying for 10s, then controlling the damper regulating valve of the powder exhaust fan to adjust to 95%, and then controlling the damper regulating valve to adjust to less than 95% and greater than 50%; after the damper regulating valve is adjusted to less than 95% and greater than 50%, controlling the outlet shut-off valve of the heating furnace to open, controlling the inlet shut-off valve of the heating furnace to open, controlling the front shut-off valve of the waste gas fan to open, controlling the hot waste gas diffusing regulating valve to adjust to 5%, controlling the hot flue gas diffusing regulating valve to adjust to 5%, when the inlet pressure of the medium-speed mill is negative pressure, controlling the front regulating valve of the waste gas fan to adjust to 10%, and the starting operation of the powder exhaust fan and the waste gas fan is completed.

[0012] In some embodiments of the present application, based on the foregoing scheme, the pre-cloth bag operation before the cloth bag drying operation includes: controlling the variable frequency rotating speed of the powder exhaust fan to reach 700r / min, and controlling the front regulating valve of the waste gas fan to adjust to 60%.

[0013] In some embodiments of the present application, based on the foregoing scheme, the execution of the cloth bag drying operation includes: when the cloth bag drying operation is executed, the inlet pressure of the medium-speed mill is controlled to be-300Pa to-500Pa relative to the pressure value of the standard atmospheric pressure, and the outlet temperature of the pulverized coal collector is controlled to reach 45℃.

[0014] In some embodiments of the present application, based on the foregoing scheme, the executing the once-inverted air operation comprises: when executing the once-inverted air operation, controlling the variable frequency rotating speed of the powder discharging fan to reach 1000 rpm, and controlling the pressure value of the inlet pressure of the medium-speed mill relative to the standard atmospheric pressure to be -1300 Pa to -1100 Pa.

[0015] In some embodiments of the present application, based on the foregoing scheme, the executing the hot blast furnace stop-burning operation comprises: controlling the blast furnace gas adjusting valve to adjust to 0%, and after delaying for 30 s, controlling the blast furnace gas cut-off valve to close; controlling the combustion air adjusting valve to adjust to 30%, controlling the outlet temperature of the medium-speed mill to be less than 70°C, and controlling the coal feeding amount of the coal feeder to be reduced to a preset tonnage.

[0016] In some embodiments of the present application, based on the foregoing scheme, the preset tonnage is 40 tons.

[0017] In some embodiments of the present application, based on the foregoing scheme, the executing the medium-speed mill stop-milling post-operation comprises: controlling the inlet adjusting valve and the front cut-off valve of the waste gas inducing fan to be closed simultaneously, and controlling the waste gas inducing fan and the powder discharging fan to be stopped in sequence; controlling the hot waste gas diffusion adjusting valve and the hot flue gas diffusion adjusting valve to be adjusted to 100%, and controlling the heating furnace outlet cut-off valve and the heating furnace inlet cut-off valve to be closed simultaneously; and controlling the combustion air adjusting valve to be adjusted to 10% to 15%, and controlling the hot flue gas diffusion adjusting valve to be adjusted to 0%.

[0018] In some embodiments of the present application, based on the foregoing scheme, the first preset time is 30 s.

[0019] From the above technical solution, the present application has at least the following advantages and positive effects:

[0020] The present application solves the problem that the current coal injection pulverizing system is manually operated, leading to uneven control of coal powder particle size, large energy loss, and high misoperation rate. The present application upgrades the coal injection pulverizing system to be intelligent, and adjusts the coal pulverizing process parameters, so that the medium-speed mill and its affiliated equipment and facilities are automatically controlled, the intelligent level of coal pulverizing is improved, and the working efficiency of coal pulverizing is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present application and, together with the specification, serve to explain the principles of the application. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained from these drawings without creative labor for those skilled in the art. In the drawings:

[0022] Figure 1A flow chart of a medium speed mill control method in one embodiment of the present application is shown.

[0023] Figure 2 A control flow chart of a medium speed mill start-up operation in one embodiment of the present application is shown.

[0024] Figure 3 A control flow chart of a medium speed mill shut-down operation in one embodiment of the present application is shown. DETAILED DESCRIPTION

[0025] Example implementations will now be described more fully with reference to the accompanying drawings. Example implementations may, however, be implemented in many different forms and should not be construed as limited to the examples set forth herein; rather, these implementations are provided so that this disclosure will be thorough and complete, and will fully convey the scope of example implementations to those skilled in the art.

[0026] Moreover, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the application. One skilled in the relevant art will recognize, however, that the

[0027] The flow charts shown in the drawings are merely illustrative examples and do not necessarily include all content and operations / steps, nor are they necessarily performed in the order described. For example, some operations / steps can be further broken down, while some operations / steps can be combined or partially combined, so the actual order of execution can be changed as appropriate.

[0028] It should be noted that the terms "first", "second", and the like, used in the description and in the claims of the present application as well as above-mentioned drawings, are used to distinguish similar objects and are not necessarily to describe a specific order or sequence. It is to be understood that the use of these terms herein is only to distinguish the different objects and not necessarily describe a specific order or sequence, and these objects can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described.

[0029] The current coal injection pulverizing system is manually controlled, and some process parameters and equipment control are set and operated by experience, which can cause uneven control of coal particle size, large energy loss, increased misoperation rate and other adverse effects. Upgrading the intelligence of the coal injection pulverizing system can enable the medium-speed mill and its auxiliary equipment to be automatically controlled, control the coal gas and air combustion ratio through expert fuzzy control and optimization control, and optimize the temperature, pressure and flow of the flue gas system, thereby improving the utilization rate of coal gas, reducing energy consumption, saving production costs, reducing the working intensity of the operator and improving the intelligence level of the iron front, thereby laying a foundation for intelligent manufacturing of the iron front. The present application adopts a medium-speed mill control method to realize one-key control of the coal injection pulverizing system, so that the medium-speed mill can be automatically started and stopped, and the intelligence level of the coal injection pulverizing system is further improved.

[0030] The implementation details of the technical solutions of the embodiments of the present application are described below in detail:

[0031] According to the present application, a medium-speed mill control method is provided, which is described below with reference to Figure 1 , Figure 1 The flowchart of the medium-speed mill control method of the present application is shown in the following steps S1 to S4:

[0032] Step S1, when the medium-speed mill is controlled to perform a mill starting action, refer to Figure 2 , Figure 2 The control flowchart of the mill starting operation in one embodiment of the present application is shown in the following figure: Figure 2 First, the running state of the coal mill peripheral equipment is checked, and after determining that the coal mill peripheral equipment is normally running, the pre-starting operation before the starting of the pulverized coal blower is performed.

[0033] In the present application, before the coal grinding process, the running state of the coal grinding peripheral equipment needs to be checked, which can be the heating furnace and the auxiliary equipment and facilities of the medium-speed mill. Only when the coal grinding peripheral equipment is in normal operation, the normal start of the medium-speed mill and the normal coal grinding process can be ensured. When checking the running state of the coal grinding peripheral equipment, the heating furnace needs to be checked first to determine whether the outlet temperature of the heating furnace reaches 65℃, whether the circulating cooling water system of the heating furnace is in normal operation, whether the nitrogen pulse purge of the powder collector of the heating furnace is normal, whether the instrument sensitivity of the heating furnace is normal, and whether the nitrogen pressure detected by the nitrogen instrument of the heating furnace is kept within the specified pressure range. If any of the detections of the heating furnace is abnormal, the system is initialized and the corresponding checking process is performed to ensure that the running state of the heating furnace can meet the production requirements. After determining that the running state of the heating furnace is normal, the running state detection of the auxiliary equipment and facilities of the medium-speed mill is performed to determine whether the external valve, instrument nitrogen pressure, and lubrication station and sealing fan of the auxiliary equipment and facilities of the medium-speed mill are in normal operation, and the auxiliary equipment and facilities of the medium-speed mill are switched to the automatic opening and closing mode. If any of the detections of the auxiliary equipment and facilities of the medium-speed mill is abnormal, the corresponding checking process is performed to ensure that the auxiliary equipment and facilities of the medium-speed mill are in normal operation. The normal start of the medium-speed mill and the normal operation of the coal grinding process are ensured.

[0034] In one embodiment of the present application, continuing to refer to Figure 2 When performing the pre-start operation before the start of the exhaust fan, it can include: controlling the damper adjusting valve of the exhaust fan to adjust to 0%, controlling the outlet adjusting valve of the mixing furnace to adjust to 95%, controlling the diffusing adjusting valve of the combustion fan to adjust to 90%, controlling the inlet adjusting valve of the exhaust gas fan to adjust to 0%, controlling the hot exhaust gas diffusing adjusting valve to adjust to 95%, and controlling the hot flue gas diffusing adjusting valve to adjust to 95%. After the damper adjusting valve of the exhaust fan, the outlet adjusting valve of the mixing furnace, the diffusing adjusting valve of the combustion fan, the inlet adjusting valve of the exhaust gas fan, the hot exhaust gas diffusing adjusting valve, and the hot flue gas diffusing adjusting valve are in place, the pre-cut valve operation before the start of the exhaust fan can be performed. When performing the pre-cut valve operation before the start of the exhaust fan, it can include: controlling the outlet cut valve of the heating furnace to close, controlling the inlet cut valve of the heating furnace to close, controlling the front cut valve of the exhaust gas fan to close, controlling the variable frequency rotating speed of the exhaust fan to reach 450 revolutions / minute, and controlling the outlet cut valve of the heating furnace, the inlet cut valve of the heating furnace, and the front cut valve of the exhaust gas fan to close in place. After the variable frequency rotating speed of the exhaust fan reaches 450 revolutions / minute, it is determined that the pre-start operation before the start of the exhaust fan is completed.

[0035] Step S2, after the pre-starting operation is completed and a first preset time is delayed, the control of the powder exhaust fan and the exhaust gas fan is started in turn, after the exhaust gas fan is started, the pre-bagging operation before the bagging is performed, after the pre-bagging operation is completed, the bagging operation is performed.

[0036] In an embodiment of the present application, the first preset time can be 30s.

[0037] In an embodiment of the present application, continuing to refer to Figure 2 When the control of the powder exhaust fan and the exhaust gas fan is started in turn, it can include: first, the control of the powder exhaust fan is performed to start the operation, and after the powder exhaust fan is started, the control of the exhaust gas fan is performed to start the operation, after the exhaust gas fan is started, the control of the damper adjustment valve of the powder exhaust fan is adjusted to 95%, then the control of the damper adjustment valve is adjusted to less than 95% and greater than 50%, after the damper adjustment valve is adjusted to less than 95% and greater than 50%, the operation of each valve after the powder exhaust fan is run is performed, the operation of each valve after the powder exhaust fan is run can include: the control of the heating furnace outlet cut-off valve is opened, the control of the heating furnace inlet cut-off valve is opened, the control of the front cut-off valve of the exhaust gas fan is opened, the control of the hot exhaust gas diffusion adjustment valve is adjusted to 5%, the control of the hot flue gas diffusion adjustment valve is adjusted to 5%, when the inlet pressure of the heating furnace inlet cut-off valve, the front cut-off valve of the exhaust gas fan, the hot exhaust gas diffusion adjustment valve, the hot flue gas diffusion adjustment valve and the medium-speed mill is negative pressure, the control of the front adjustment valve of the exhaust gas fan is adjusted to 10%, the control of the powder exhaust fan and the exhaust gas fan is started.

[0038] In an embodiment of the present application, continuing to refer to Figure 2After the exhaust gas fan is started, the pre-bagging operation before bagging is performed, which can include: controlling the variable frequency speed of the powder exhaust fan to reach 700 rpm, and when the variable frequency speed of the powder exhaust fan reaches 700 rpm, controlling the variable frequency speed of the powder exhaust fan to increase by 50 rpm for five times successively based on 450 rpm, and the interval between each time is 30 s. For example: the variable frequency speed is increased by 50 rpm for the first time based on 450 rpm, so that the variable frequency speed reaches 500 rpm, and after the variable frequency speed reaches 500 rpm, a delay of 30 s is performed, and then the variable frequency speed is increased by 50 rpm for the second time, so that the variable frequency speed reaches 550 rpm, and after the variable frequency speed reaches 550 rpm, a delay of 30 s is performed, and then the variable frequency speed is increased by 50 rpm for the third time, so that the variable frequency speed reaches 600 rpm, and the same rule is followed until the variable frequency speed is increased by 50 rpm for the fifth time, so that the variable frequency speed of the powder exhaust fan reaches 700 rpm.

[0039] It should be noted that when the variable frequency speed of the powder exhaust fan is controlled to increase for five times successively, the front regulating valve of the exhaust gas fan needs to be adjusted accordingly. When the variable frequency speed is increased for each time, the front regulating valve of the exhaust gas fan is controlled to adjust the opening degree accordingly, wherein the adjustment times can be five times, and specifically, the opening degree can be increased by 10% each time. The adjustment opening degree of the front regulating valve of the exhaust gas fan is based on 10%, and each time the variable frequency speed is increased, the opening degree of the front regulating valve of the exhaust gas fan is adjusted once, so that when the variable frequency speed of the powder exhaust fan reaches 700 rpm, the front regulating valve of the exhaust gas fan is adjusted to 60%. When the variable frequency speed of the powder exhaust fan reaches 700 rpm and the front regulating valve of the exhaust gas fan is adjusted to 60%, the pre-bagging operation before bagging is completed.

[0040] In an embodiment of the present application, continuing to refer to Figure 2 After the pre-bagging operation before bagging is completed, the bagging operation is performed, which can include: when the bagging operation is performed, the inlet pressure of the medium-speed mill is controlled to be-300 Pa to-500 Pa relative to the standard atmospheric pressure, and the outlet temperature of the coal powder collector is controlled to reach 45°C. The bagging operation is completed.

[0041] Step S3, continuing to refer to Figure 1 and Figure 2After the cloth bag baking operation is completed, a one-time air reversing operation is performed, when the outlet temperature of the medium-speed mill reaches 80℃, the main motor of the medium-speed mill is started and the blast furnace gas cut-off valve is opened, when the outlet temperature reaches 90℃, the coal feeder is started, and the medium-speed mill grinding operation is completed.

[0042] In an embodiment of the present application, continuing to refer to Figure 2 The one-time air reversing operation can include: when the one-time air reversing operation is performed, the variable frequency rotating speed of the powder exhaust fan is controlled to reach 1000 rpm, and it is noted that when the variable frequency rotating speed of the powder exhaust fan is controlled to reach 1000 rpm, the variable frequency rotating speed of the powder exhaust fan is controlled to increase by 100 rpm three times successively based on 700 rpm, and the interval between each time is 25 s. For example, the variable frequency rotating speed is increased by 100 rpm for the first time based on 700 rpm, so that the variable frequency rotating speed reaches 800 rpm, and after the variable frequency rotating speed reaches 800 rpm, a delay of 25 s is performed, then the variable frequency rotating speed is increased by 100 rpm for the second time, so that the variable frequency rotating speed reaches 900 rpm, and after the variable frequency rotating speed reaches 900 rpm, a delay of 25 s is performed, then the variable frequency rotating speed is increased by 100 rpm for the third time, so that the variable frequency rotating speed reaches 1000 rpm. After the variable frequency rotating speed of the powder exhaust fan reaches 1000 rpm, the inlet pressure of the medium-speed mill relative to the standard atmospheric pressure is controlled to be-1300 Pa to-1100 Pa. The one-time air reversing operation is completed. When the outlet temperature of the medium-speed mill reaches 80℃, the main motor of the medium-speed mill is started and the blast furnace gas cut-off valve is opened, when the outlet temperature reaches 90℃, the coal feeder is started, and the medium-speed mill grinding operation is completed.

[0043] Step S4, referring to Figure 3 , Figure 3 A control flow chart of the medium-speed mill stopping operation in an embodiment of the present application is shown. When the medium-speed mill stopping operation is performed, the hot blast stove stopping operation is performed first, when the outlet temperature of the medium-speed mill is less than 50℃, the coal feeder is stopped, and the secondary air reversing operation is performed, when the variable frequency rotating speed of the powder exhaust fan is reduced to 450 rpm, the inlet regulating valve of the waste gas fan is adjusted to a preset valve position, then the main motor of the medium-speed mill is stopped, and finally the medium-speed mill stopping operation is performed. The medium-speed mill stopping operation is completed.

[0044] In an embodiment of the present application, continuing to refer to Figure 3, the performing the hot stove stop-burning operation can comprise: controlling the blast furnace gas adjusting valve to adjust to 0%, and controlling the blast furnace gas cut-off valve to close after a delay of 30s; controlling the combustion air adjusting valve to adjust to 30%, controlling the outlet temperature of the medium-speed mill to be less than 70°C, and controlling the coal feeding amount of the coal feeder to reduce to a preset tonnage.

[0045] In an embodiment of the present application, the preset tonnage can be 40 tons.

[0046] In the present application, the above description continues to refer to Figure 3 In the performing of the hot stove stop-burning operation, the blast furnace gas adjusting valve can be controlled to adjust to 0%, when the blast furnace gas adjusting valve is adjusted to 0%, the blast furnace gas adjusting valve can be controlled to reduce by 2% each time, and the interval between each adjustment is 30s, after the blast furnace gas adjusting valve is adjusted to 0% and a delay of 30s, the blast furnace gas cut-off valve is controlled to close. The combustion air adjusting valve is controlled to adjust to 30%, when the combustion air adjusting valve is controlled to adjust to 30%, the combustion air adjusting valve is controlled to reduce by 2% each time until it is adjusted to 30%. The outlet temperature of the medium-speed mill is controlled to be less than 70°C, and the coal feeding amount of the coal feeder is controlled to reduce by 5 tons each time from the set initial basis until it is reduced to a preset tonnage (40 tons), wherein it should be noted that the variable frequency rotating speed of the powder exhaust fan is reduced by 20 revolutions each time while reducing by 5 tons, so as to maintain the pressure difference of the inlet pressure of the medium-speed mill relative to the standard atmospheric pressure to be 1000Pa-2000Pa. When the outlet temperature of the medium-speed mill is less than 50°C, the coal feeder is controlled to stop, and a secondary air reversal operation is performed, in the performing of the secondary air reversal operation, the variable frequency rotating speed of the powder exhaust fan is controlled to decrease in a gradient manner, and each time the gradient decrease is 100 revolutions, until the variable frequency rotating speed of the powder exhaust fan is reduced to 450 revolutions / minute, and the pressure difference of the inlet pressure of the medium-speed mill relative to the standard atmospheric pressure is controlled to be 1000Pa-1500Pa, after the variable frequency rotating speed of the powder exhaust fan is reduced to 450 revolutions / minute, the inlet adjusting valve of the waste gas fan is controlled to adjust to a preset valve position, then the main motor of the medium-speed mill is controlled to stop, and finally a medium-speed mill stop-milling operation is performed, and the medium-speed mill stop-milling operation is completed.

[0047] In an embodiment of the present application, the above description continues to refer to Figure 3 The performing of the medium-speed mill stop-milling operation can comprise: controlling the inlet adjusting valve and the front cut-off valve of the waste gas fan to close at the same time, and controlling the waste gas fan and the powder exhaust fan to stop in turn; controlling the hot waste gas diffusion adjusting valve and the hot flue gas diffusion adjusting valve to adjust to 100%, and controlling the heating furnace outlet cut-off valve and the heating furnace inlet cut-off valve to close at the same time; controlling the combustion air adjusting valve to adjust to 10%-15%, and controlling the hot flue gas diffusion adjusting valve to adjust to 0%. When all the valves are in place, the medium-speed mill stop-milling operation is completed.

[0048] From the above technical solutions, the present application has at least the following aspects of advantages and positive effects:

[0049] Firstly, by using the scheme proposed in the present application, the present application solves the problems of manual operation of the coal injection grinding system, uneven control of coal powder particle size, large energy loss, and high misoperation rate. The present application upgrades the coal injection grinding system intelligently, and adjusts the grinding process parameters, so that the medium-speed mill and its auxiliary equipment and facilities are automatically controlled, the intelligent level of coal grinding is improved, and the work efficiency of coal grinding is ensured.

[0050] Secondly, by using the scheme proposed in the present application, the automatic one-key operation of starting, grinding and stopping of the medium-speed mill in the coal grinding process is realized, the differential operation of personnel is avoided, the control precision and the stability of the equipment logic control are improved, and the whole coal injection grinding system realizes the automation of the whole process, which provides favorable conditions for large work type and large post operation.

[0051] Thirdly, by using the scheme proposed in the present application, the intelligent upgrading of the coal injection grinding system enables the medium-speed mill and its auxiliary equipment and facilities to realize automatic control. The proportion of coal gas and air combustion is controlled by expert fuzzy control and optimization control, so that the temperature, pressure and flow of the flue gas system are optimally controlled, the utilization rate of coal gas is improved, the energy consumption is reduced, and the production cost is saved.

[0052] Fourthly, by using the scheme proposed in the present application, the working intensity of the operator can be reduced, the intelligent level of the iron front is improved, and the foundation for intelligent manufacturing of the iron front is laid.

[0053] Other embodiments of the present application will be apparent to those skilled in the art from consideration of the specification and practice of the embodiments disclosed herein. The present application is intended to cover any variations, uses or adaptive changes of the present application following the general principles thereof and including those falling within the prior art concepts or adaptations that are within the scope of the present application.

[0054] Although the present application has been described with reference to several exemplary embodiments, it is understood that the terms used are illustrative and not restrictive, and that the present application is not limited to any of the above details. Since the present application can be embodied in many different forms without departing from the spirit or essential characteristics thereof, it should be understood that the above-described embodiments are not limited to the details thereof but are to be interpreted broadly within the scope and spirit of the appended claims, and all changes and modifications that fall within the scope of the claims or their equivalents are intended to be embraced by the appended claims.

Claims

1. A method for controlling a medium-speed mill, characterized in that, The method includes: When controlling the medium-speed mill to perform the start-up action, first check the operating status of the peripheral equipment of the coal mill. After confirming that the peripheral equipment of the coal mill is operating normally, perform the pre-start operation before starting the exhaust fan. Control the damper regulating valve of the exhaust fan to 0%, control the outlet regulating valve of the mixing furnace to 95%, control the vent regulating valve of the combustion fan to 90%, control the inlet regulating valve of the exhaust gas fan to 0%, control the hot exhaust gas vent regulating valve to 95%, control the hot flue gas vent regulating valve to 95%, control the outlet shut-off valve of the heating furnace to close, control the inlet shut-off valve of the heating furnace to close, control the front shut-off valve of the exhaust gas fan to close, and control the variable frequency speed of the exhaust fan to reach 450 rpm. After the pre-start operation is completed and a first preset time is delayed, the exhaust fan and the induced waste gas fan are started sequentially. Then, the damper regulating valve of the exhaust fan is adjusted. After the damper regulating valve is adjusted to less than 95% and greater than 50%, the furnace outlet shut-off valve is opened, the furnace inlet shut-off valve is opened, the induced waste gas fan's front shut-off valve is opened, the hot waste gas venting regulating valve is adjusted to 5%, the hot flue gas venting regulating valve is adjusted to 5%, and when the inlet pressure of the medium-speed mill is negative, the induced waste gas fan's front regulating valve is adjusted to 10%. The start-up operation of the exhaust fan and the induced waste gas fan is completed. After the exhaust gas fan is started, a pre-drying operation is performed before the bag drying operation is performed. After the pre-drying operation is completed, the bag drying operation is performed. After the bag drying operation is completed, a reverse air operation is performed. When the outlet temperature of the medium speed mill reaches 80°C, the main motor of the medium speed mill is started and the blast furnace gas shut-off valve is opened. When the outlet temperature reaches 90°C, the coal feeder is started, and the start-up operation of the medium speed mill is completed. When performing the medium-speed mill shutdown operation, the hot blast stove is shut down first. The blast furnace gas regulating valve is adjusted to 0%, and after a 30-second delay, the blast furnace gas shut-off valve is closed. The combustion air regulating valve is adjusted to 30%, and the outlet temperature of the medium-speed mill is controlled to be less than 70°C. The coal feeder's coal feed rate is reduced to a preset tonnage. When the outlet temperature of the medium-speed mill is less than 50°C, the coal feeder is stopped, and a secondary reverse air operation is performed. When the frequency conversion speed of the exhaust fan is reduced to 450 rpm, the inlet regulating valve of the induced waste gas fan is adjusted to a preset valve position. Then, the main motor of the medium-speed mill is stopped. Finally, the medium-speed mill shutdown operation is performed, and the medium-speed mill shutdown operation is completed.

2. The method according to claim 1, characterized in that, The control of the dust removal fan and the exhaust gas fan to start sequentially includes: The dust removal fan is controlled to start, and after a 10-second delay, the exhaust gas fan is controlled to start. After a 10-second delay, the damper regulating valve of the dust removal fan is controlled to adjust to 95%, and then the damper regulating valve is controlled to adjust to less than 95% and greater than 50%.

3. The method according to claim 2, characterized in that, The pre-drying operation of the cloth bag before drying includes: controlling the variable frequency speed of the powder discharge fan to reach 700 rpm, and controlling the front regulating valve of the exhaust gas fan to adjust to 60%.

4. The method according to claim 3, characterized in that, The operation of drying the cloth bag includes: When performing the bag drying operation, the inlet pressure of the medium-speed mill is controlled to be -300Pa to -500Pa relative to the standard atmospheric pressure, and the outlet temperature of the pulverized coal collector is controlled to reach 45℃.

5. The method according to claim 4, characterized in that, The execution of a single reversing operation includes: During a single reverse air operation, the variable frequency speed of the powder discharge fan is controlled to reach 1000 rpm, and the inlet pressure of the medium-speed mill is controlled to be -1300 Pa to -1100 Pa relative to the standard atmospheric pressure.

6. The method according to claim 5, characterized in that, The preset tonnage is 40 tons.

7. The method according to claim 6, characterized in that, The operation after stopping the medium-speed mill includes: The inlet regulating valve and the front shut-off valve of the exhaust gas blower are closed simultaneously, and the exhaust gas blower and the dust discharge blower are stopped in sequence. The hot exhaust gas venting regulating valve and the hot flue gas venting regulating valve are adjusted to 100%, and the heating furnace outlet shut-off valve and the heating furnace inlet shut-off valve are simultaneously closed; The combustion air regulating valve is adjusted to 10%~15%, and the hot flue gas venting regulating valve is adjusted to 0%.

8. The method according to claim 1, characterized in that, The first preset time is 30 seconds.

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