WO2014101790A1

WO2014101790A1 - Frequency change control method and system for main exhaust fan of sintering system

Info

Publication number: WO2014101790A1
Application number: PCT/CN2013/090548
Authority: WO
Inventors: 袁立新; 申伟杰; 孙超; 卢杨权; 高鹏双
Original assignee: 中冶长天国际工程有限责任公司
Priority date: 2012-12-27
Filing date: 2013-12-26
Publication date: 2014-07-03
Also published as: CN103033050B; BR112015014193A2; BR112015014193B1; RU2647411C2; CN103033050A; RU2015128275A

Abstract

A frequency change control method for a main exhaust fan of a sintering system comprises: (1) obtaining sintered material quantity; (2) calculating the vertical sintering speed of a material layer by using the sintered material quantity and a preset burn-through point, and calculating effective large flue air quantity by using a relationship between the vertical sintering speed and effective air quantity; (3) detecting smoke components of a large flue; (4) calculating an effective air rate by using the smoke components of the large flue, and calculating target large flue air quantity; (5) by using the corresponding relationship between the large flue air quantity and the main exhaust fan rotation speed, searching for target main exhaust fan rotation speed corresponding to the target large flue air quantity; and (6) regulating the current main exhaust fan frequency to the target main exhaust fan frequency corresponding to the target main exhaust fan rotation speed. A frequency change control system for the main exhaust fan of the sintering system can reduce the consumption and loss of electricity of the sintering system as the result of the mismatching between the power provided in the operation of the main exhaust fan and the system load.

Description

Sintering system main exhaust fan frequency conversion control method and system

This application claims priority to Chinese Patent Application No. 201210578971.5, entitled "Sintering System Spindle Fan Frequency Conversion Control Method and System", filed on December 27, 2012, the entire contents of which are incorporated herein by reference. In the application. Technical field

The invention relates to a sintering system control technology, in particular to a sintering system main exhaust fan frequency conversion control method and system. Background technique

With the rapid development of modern industry, the scale of steel production is getting larger and larger, and energy consumption is also increasing. Energy-saving and environmental protection indicators have increasingly become an important factor in the steel production process. In steel production, iron-bearing raw materials ore must be processed by a sintering system before entering the blast furnace smelting, that is, various powdered iron-containing raw materials are blended with an appropriate amount of fuel and flux, and an appropriate amount of water is added, after mixing and pelletizing. The cloth is fired on a sintering trolley to cause a series of physicochemical changes to form a sinter that is easily smelted. This process is called sintering.

The sintering system mainly includes sintering trolley, mixer, main exhaust fan, ring cooler and other equipment. The general process flow is shown in Figure 1: The various raw materials are mixed in the batching room 1 to form a mixture material and a mixture. After entering the mixer 2, the hook and the ball are plucked, and then uniformly distributed on the sintering trolley 5 through the round roller feeder 3 and the nine-roller 4 to form a material layer, and the ignition fan 12 and the igniter fan 11 start the material ignition. Sintering process. The sintered ore obtained after the sintering is completed is crushed by a single-roll crusher 8 and then enters the ring cooler 9 to be cooled, and finally sieved and granulated and sent to the blast furnace or the finished mineral warehouse. Among them, the oxygen required for the sintering process is provided by the main exhaust fan 10, and a plurality of vertical side-by-side bellows 6 are arranged under the sintering trolley 5, and a large flue (or flue) disposed horizontally below the bellows 6 is 7 The road 7 is connected to the main exhaust fan 10, and the negative air generated by the main exhaust fan 10 through the large flue 7 and the wind box 6 passes through the trolley to provide a combustion air for the sintering process.

In order to ensure the quality of the sintering, the speed of the sintering trolley and the thickness of the layer on the sintering trolley are usually adjusted at the initial stage of sintering, so that the sintering end point is basically maintained at a predetermined fixed position (generally the second last bellows on the sintering trolley) . Once the system is stabilized, the thickness of the sinter layer is usually no longer changed. The state of the sintered main exhaust fan is stable, and the rotation speed is not adjustable. The negative pressure of the entire sintering system is maintained by adjusting the main bleeder. Stable, the adjustment of the sintering end point is maintained by adjusting the speed of the sintering trolley. On the other hand, in the actual production process, due to market factors, raw material storage factors, sinter storage factors, etc., it is sometimes necessary to adjust the sinter output, and then adjust the amount of sintered materials, general sintered material density, sintering trolley The width is determined, and the amount of sintered material changes to change the speed of the sintering trolley and/or the thickness of the material layer. Obviously, as long as the amount of sintered material changes, such as the sintering negative pressure, the sintering end point deviates from the preset fixed position, and the sintering quality cannot be guaranteed. In the original mode, only the main exhaust valve opening is changed to change. Negative pressure is adjusted.

In the actual working process, in order to cope with the influence of the change of sintering conditions and the change of production demand on the sintering process (ie the quality of sintered ore), in the existing sintering process, the main exhaust fan of the sintering system is usually according to its maximum design speed. In operation, the adjustment process adopts the damper adjustment mode, which inevitably leads to excessive power consumption and loss. Summary of the invention

In view of the above, an object of the present invention is to provide a frequency conversion control method and system for a main exhaust fan of a sintering system to solve the problem of excessive power consumption and loss of the sintering system.

To achieve the above objective, an embodiment of the present invention provides a method for controlling a frequency conversion of a main exhaust fan of a sintering system, the method comprising the following steps:

1) obtaining the amount of sintered material;

2) calculating the vertical sintering speed of the material layer by using the amount of sintering material and the preset sintering end point, and calculating the effective air volume of the large flue using the relationship between the vertical sintering speed and the effective air volume;

3) detecting smoke constituents of large flue;

4) calculating the effective wind rate by using the smoke component of the large flue gas, and calculating the target air volume of the large flue, wherein the target flue volume of the large flue is equal to the effective flue volume of the large flue divided by the effective wind rate;

5) Using the correspondence between the air volume of the large flue and the speed of the main exhaust fan, and finding the target speed of the main exhaust fan corresponding to the target air volume of the large flue;

6) adjusting the current frequency of the main exhaust fan to the target frequency of the main exhaust fan corresponding to the target speed of the main exhaust fan.

According to the above control method, since the target volume of the large flue is obtained according to the change of the amount of the sintered material, And, according to the target flue volume of the large flue, the frequency of the main exhaust fan is finally adjusted, so that the frequency of the main exhaust fan can be dynamically adjusted according to the change of the amount of the sintered material, thereby realizing the dynamic balance between the power consumption of the main exhaust fan and the change of the load size, thereby reducing the sintering. In the process, the main exhaust fan power and the load size do not match the power consumption and loss, and can also avoid the existing method only by adopting a large energy consumption adjustment method that changes the bellows valve opening to change the negative pressure.

In another embodiment based on the above control method, the method further includes the following steps:

Detecting the current air volume of the large flue;

Calculate the difference between the current air volume of the large flue and the target air volume of the large flue;

If the difference is greater than or equal to the set threshold, adjusting the current frequency of the main exhaust fan to the target frequency of the main blower corresponding to the target air volume of the large flue, otherwise, adjusting the opening degree of the bellows valve to make the effective flue of the large flue It is equal to the effective air volume of the large flue target air volume before the bellows valve is adjusted. Compared with the scheme, it can achieve energy savings of about 15% and annual energy savings of about 10.8 million kWh, which can bring many economic and social benefits such as capital saving and pollution reduction. (The annual output of 180 square meters of sintering machine is 1.8 million tons, and the average electricity consumption per ton of product is 40 degrees). If the embodiment of the present invention is applied to the control of a 360-square-meter sintering machine, the power saving can be achieved by about 15% compared with the solution without using the present invention, and the annual energy saving is about 21.6 million degrees, which can bring capital saving and reduce pollution. Many economic and social benefits such as emissions.

In particular, there are many interrelated devices in the sintering system. Relatively speaking, devices associated with more other devices can be called system devices, such as sintering trolleys, main exhaust fans, etc. The connected equipment can be called a local device, such as a bellows, a bellows valve, and the like. Obviously, adjusting the system equipment, such as adjusting the speed of the trolley and adjusting the frequency of the main exhaust fan, has a greater impact on the system; while adjusting the local equipment, the impact on the system is small. Therefore, in the sintering system, the system is affected by the local equipment, rather than by the adjustment of the system equipment, which contributes to system stability and prolongs the life of the equipment. Therefore, in the embodiment of the present invention, only when the difference between the current air volume of the large flue and the target air volume of the large flue is greater than or equal to the set threshold, if the difference is greater than or equal to the set threshold, the current main fan is adjusted. The frequency is to the target frequency of the main blower corresponding to the target volume of the large flue. Otherwise, the opening of the bellows valve is adjusted so that the effective flue volume of the large flue is equal to the effective air volume of the large flue target air volume before the bellows valve is adjusted. The embodiment of the invention is based on the premise of maintaining the speed of the trolley, the frequency of the main exhaust fan and the stability of the main exhaust valve. When the air volume changes greatly, the adjustment target is achieved by adjusting the frequency of the main exhaust fan, and when the air volume changes little, the adjustment target is achieved by adjusting the opening degree of the sintering bellows valve, thereby realizing the vertical speed of adjusting the sintering of the material, thereby controlling the sintering more precisely. Process and sintering end point. Of course, the main exhaust fan damper can also be adjusted to achieve the adjustment target, but in order to ensure stable transition of the operating conditions of the system, adjusting the bellows damper is the preferred solution for damper adjustment. It can be seen that the embodiment of the present invention provides an adjustment manner that is beneficial to system stability.

In a preferred embodiment, the amount of sintered material is obtained in the following manner.

21) continuously or periodically detecting the flow of material at all fabric outlets of the distributor;

22) The mean value of all fabric outlet material flows obtained by cumulative detection;

23) Calculate the amount of sintered material based on the accumulated result.

In the preferred embodiment, the average of the continuous or periodic detection results of all the cloth outlets is accumulated by continuously or periodically detecting the amount of material of all the fabric outlets per unit time, and the amount of the sintered material is calculated based on the accumulated results. Since the measurement error can be reduced by measuring the amount of the sinter material by multiple measurements and by the average of the multiple measurement results, the accuracy of the obtained sintered material amount can be improved. In addition, the scheme detects the amount of material per unit time of the fabric outlet of the fabric machine, that is, it is detected at the source of the material conveying, and can obtain the real quantity of the sintered material in the shortest possible time, and reduce the lag of the data obtained by the sintering material amount. The resulting adjustment lags.

Based on the above preferred scheme, the further optimization scheme is:

Between the steps 22) and 23), the method further comprises: determining whether the difference between the two successive accumulation results is within a set range, and if yes, proceeding to step 23); otherwise, proceeding to step 22).

The program judges the results of multiple accumulations, and eliminates the sudden change of the amount of sintered material caused by accidental factors to obtain a more accurate amount of sintered material.

Preferably, the smoke component of each of the bellows is periodically detected, and the average of the smoke components detected a plurality of times is taken as the smoke component of each of the bellows.

By periodically detecting the smoke component in the large flue, the scheme can make the calculation of the effective wind rate and the target air volume more accurate, and then periodically update the target air volume, and finally achieve an accurate match between the target air volume and the sintered material quantity, and ensure the main The adjustment of the frequency value of the exhaust fan is matched to the degree of sintering material.

The embodiment of the invention also provides a frequency conversion control system for the main exhaust fan of the sintering system, comprising:

An initial parameter acquisition unit, configured to obtain a quantity of sintered material; a first calculating unit, configured to calculate a vertical sintering speed of the material layer by using a sintering material amount and a preset sintering end point, and calculating a effective air volume of the large flue using a relationship between a vertical sintering speed and an effective air volume; a smoke component detecting unit, Used to detect the smoke component of the flue system of the sintering system;

a second calculating unit, configured to calculate an effective wind rate by using the large flue gas component, and calculate a large flue target air volume by dividing the large flue target air volume by the large flue effective air volume by the effective flue gas; a unit, configured to use a correspondence relationship between a large flue air volume and a main exhaust fan speed to find a target blower target speed corresponding to a large flue target air volume;

And a controller, configured to adjust a current frequency of the main exhaust fan to a target frequency of the main exhaust fan corresponding to the target speed of the main exhaust fan.

The beneficial effects obtained by the above control system are referred to the beneficial effects of the above control method portion, and will not be further described herein. DRAWINGS

In order to more clearly illustrate the embodiments of the present invention, the drawings used in the embodiments or the description of the prior art are described in the following, and it is obvious that the drawings in the following description are some embodiments of the present invention. Other embodiments of the invention may be derived from the drawings without departing from the scope of the invention.

Figure 1 is a schematic view showing the structure of a conventional sintering system;

2 is a schematic flow chart of a frequency conversion control method for a main exhaust fan of a sintering system according to Embodiment 1 of the present invention;

3 is a schematic flow chart of a frequency conversion control method for a main exhaust fan of a sintering system according to a second embodiment of the present invention;

4 is a schematic flow chart of a frequency conversion control method for a main exhaust fan of a sintering system according to a third embodiment of the present invention;

5 is a schematic flow chart of a frequency conversion control method for a main exhaust fan of a sintering system according to a fourth embodiment of the present invention;

6 is a schematic flow chart of a frequency conversion control method for a main exhaust fan of a sintering system according to Embodiment 5 of the present invention; 7 is a schematic structural view of a frequency conversion control system for a main exhaust fan of a sintering system according to Embodiment 6 of the present invention;

8 is a schematic structural view showing a frequency conversion control system of a main exhaust fan of a sintering system according to Embodiment 7 of the present invention;

Fig. 9 is a schematic view showing the structure of a main blower frequency conversion control system of a sintering system according to an eighth embodiment of the present invention. detailed description

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is a partial embodiment of the invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

In a sintering system, the load usually manifests in various forms, such as the amount of sintered material, the thickness of the layer, and even due to the correlation of the equipment, one device may be the load of another associated device. For example, the speed of the trolley may be the main exhaust fan. Load. In practice, there are many reasons, such as equipment failure, design changes, resulting in load changes or fluctuations, which change or affect the balance and stability of the sintering system. At this time, it is necessary to change the working state of the system-related equipment, that is, to carry out the system. Adjustment, otherwise there will be problems such as insufficient sintering quality, or environmental pollution, excessive energy consumption. Embodiment 1

Please refer to FIG. 2, which shows a flow chart of a frequency conversion control method for a main exhaust fan of a sintering system according to Embodiment 1 of the present invention.

The control method provided by the embodiment of the present invention aims to adaptively adjust the main exhaust fan according to the change of the amount of the sintered material under the premise of ensuring the quality of the sintered ore (ie, the sintering end point of the sintered ore is unchanged) when the amount of the sintered material changes. The frequency is to reduce the power consumption and loss caused by the mismatch between the main exhaust fan frequency and the amount of sintered material in the sintering process. The process shown in Figure 2 includes:

5101. Obtain the amount of sintered material.

In the actual working process, due to market factors, raw material storage factors, sinter storage factors, etc., the sinter output of the sintering system needs to be continuously adjusted, and the amount of sintered material may need to be continuously adjusted. Even if the amount of sintered material has been determined, the amount of sintered material may vary during different time periods due to the stability of the equipment. In order to dynamically change the frequency of the main exhaust fan with the amount of the sintered material, it is necessary to adaptively adjust the frequency of the main exhaust fan according to the dynamic change of the amount of the sintered material, so that the amount of the sintered material of the sintered system is obtained. Of course, the amount of the sintered material may be a value set in advance according to the production schedule, or may be a value detected by an actual detecting device.

5102. Calculate the effective air volume of the large flue.

The effective air volume refers to the amount of air involved in combustion during the sintering of the unit material. The effective air volume of the large flue refers to the amount of air involved in combustion under the current amount of sintered material. In this embodiment, the sintering end point of the sintered ore is preset, so that the amount of the sintered material obtained in the step S101 and the preset sintering end point can be used to calculate the vertical sintering speed of the layer, and the vertical sintering speed is utilized and effective. The relationship between the air volume calculates the effective air volume of the large flue.

The specific calculation process is:

E=S trolley *H material layer *V trolley * p ( 1 )

Where: E is the amount of sintered material per unit time; the car is the width of the sintering trolley; is the thickness of the layer; the car is the speed of the sintering trolley; p is the density of the sintered material.

During the sintering process, it is necessary to ensure that the end point of the sintering is unchanged. At this time, the material layer is just burned through when it reaches the end of the sintering, the time taken for the material layer to be burnt through, and the time from the starting position of the sintering trolley to the end of the sintering. Time t _{2 is} equal, ie:

Ti=t ₂ ( 2 )

And, tfH material layer / V丄 (3)

Where: is the thickness of the layer; is the vertical sintering speed.

And, t ₂ = N/V trolley, (4)

Where: N is the distance from the preset sintering end point to the sintering starting position, and the car is the sintering trolley speed. Bring the above formula (2) ( 3 ) ( 4 ) into the formula (1) to obtain:

VFE/S trolley / p /N ( 5 )

Referring to the above formula (5), since the amount of sintered material E has been obtained in step S101, for the sintering system for producing a specific material, the distance N of the predetermined sintering end point from the sintering starting position is known, the sintering trolley width and sintering The material density p is a known amount that is constant, so that the vertical sintering speed Vh of the layer can be obtained.

In the production process, the vertical sintering speed has the following relationship with the effective air volume:

VFQ has / E / Q _T standard ( 6 )

Among them: (3⁄4■ is the effective flue volume of the large flue, and Q is the air volume required to participate in the combustion of the unit material under standard conditions. The parameter is determined by the type of material, and the Q _T standard is a known parameter.

By formula (6), combined with the amount of sintered material, the effective flue volume of the large flue can be calculated, that is, the effective flue volume of the large flue corresponding to the sintering yield obtained in step S101.

5103. Detecting smoke components of a large flue.

In this step, the flue gas component is detected by the flue gas analyzer, and the detection result is used to calculate the effective wind rate.

Of course, the flue gas components of the large flue can be directly detected in the large flue, or can be calculated by detecting the flue gas components of each bellows. Preferably, the smoke component of each bellows is detected; and the flue gas that has just participated in the sintering reaction is most likely to reflect the actual sintering process, so this method can improve the detection accuracy of the smoke component of the large flue. At the same time, the average value of the flue gas components of each bellows is used as the smoke component of the large flue gas, which can further improve the accuracy of the smoke component measurement of the large flue, and reduce the influence of the sudden change of the individual bellows components caused by accidental factors on the test results.

A more preferred way is to periodically detect the smoke component of each bellows and use the average of the smoke components detected multiple times as the smoke component of each bellows. By periodically detecting the composition of the flue gas, the adjusted main blower frequency is more precisely matched to the amount of sintered material, which optimizes the cycle adjustment of the main blower frequency.

5104. Calculate the target air volume of the large flue. The effective flue rate is calculated using the flue gas component of the large flue gas, and the target flue volume of the large flue is calculated, wherein the target flue volume of the large flue is equal to the effective flue volume of the large flue divided by the effective wind rate. The effective wind rate refers to the ratio of the effective air volume to the total air volume during the sintering process.

During the sintering of the material layer, the oxygen in the air volume generated by the main exhaust fan is not completely consumed, but only a part of the oxygen is involved in the sintering reaction. Therefore, the oxygen content of the material during the sintering process can be understood by the flue gas component. In the present embodiment, the smoke component of the large flue gas is detected, and the contents of 0 ₂ , CO, C0 ₂ , N ₂ , NO, and N0 ₂ per unit volume of the flue gas are mainly detected.

Since the air enters the sintering reaction process, oxygen needs to participate in the iron ore solid phase reaction and coke combustion reaction. Therefore, after the oxygen in the intake gas passes through the sintering process, the amount of oxygen in the flue gas changes; The solid phase reaction of iron ore, so nitrogen exists in the form of NO, N0 ₂ , N ₂ after the sintering process, and can be accurately measured in the flue gas.

According to the law of material invariance, the content of nitrogen and oxygen in the air is stable, so that the amount of nitrogen and oxygen entering the large flue can be calculated according to the amount of nitrogen in the flue gas and the amount of nitrogen being oxidized, and according to the measured The amount of oxygen remaining in the flue gas can be accurately calculated using the formula (a).

The amount of oxygen in the air = the amount of oxygen remaining in the flue gas + the amount of oxygen involved in the reaction

The amount of nitrogen in the air - ~ the amount of nitrogen in the flue gas + the amount of oxidized nitrogen ~ ( _a ) where:

The amount of oxygen in the air/the amount of nitrogen in the air is a constant; the amount of oxidized nitrogen can be calculated by the amount of NO and N0 ₂ detected in the flue gas analyzer; the amount of nitrogen in the flue gas can also be detected by the flue gas analyzer. The amount of N ₂ is calculated.

Therefore, the amount of oxygen involved in the reaction can be calculated.

When the amount of oxygen involved in the reaction is calculated, the effective flue rate K of the large flue can be calculated by using the formula (b).

κ = mechanical fiber * Luo

Participate in the amount of oxygen reacted + the amount of residual oxygen in the flue gas b) where: K is the effective flue rate of the large flue, and the amount of residual oxygen in the flue gas can be checked by the flue gas analyzer The measured amount of 0 ₂ is calculated.

The target flue volume Q _{s of the} large flue is calculated by the following formula (8).

Q _{S #} =Q has /K ( 8 )

Step S105: Find a target speed of the main exhaust fan.

Using the correspondence relationship between the large flue air volume and the main exhaust fan speed, the target blower target speed corresponding to the large flue target air volume is searched, and the corresponding relationship between the large flue air volume and the main exhaust fan speed refers to the large flue is different. In the actual working process, the speed of the main exhaust fan is obtained through experiments, detection and statistics.

Step S106: Adjust the frequency of the main exhaust fan.

The main blower target frequency corresponding to the main blower target speed is adjusted by using the main blower target speed obtained in step S105, thereby adjusting the main blower frequency.

The technical solution provided in the first embodiment obtains the target flue volume of the large flue according to the obtained amount of the sintered material and the preset sintering end point, and finally adjusts the main exhaust fan frequency by using the target flue volume of the large flue, and finally realizes the current frequency adjustment of the main exhaust fan. The target frequency direction of the main exhaust fan with the amount of sintered material is changed, and the main exhaust fan is adaptively adjusted according to the change of the amount of the sintered material, which can reduce the electric energy consumption and loss of the sintering process as a whole.

According to the first embodiment, as long as the amount of the sintered material as the load changes, the frequency of the main exhaust fan needs to be adjusted, so that the power consumption of the main exhaust fan is adapted to the change of the load, thereby achieving energy saving. However, the main exhaust fan acts as a system device, and its adjustment can adversely affect the stability of the entire sintering system. Therefore, an additional embodiment based on the first embodiment provides an improved solution for adjusting the main exhaust fan when the load, that is, the amount of the sintered material changes greatly, and adjusting the bellows valve opening when the load change is small. In this way, the adjustment of the main exhaust fan and the adjustment of the opening of the bellows valve are combined. When the load changes little, the adjustment of the bellows valve reaches the effect of adjusting the frequency of the main exhaust fan, thereby achieving energy saving adjustment with less influence on the entire sintering system. .

Specifically, between step S104 and step S105 of the first embodiment, the following steps are further included:

51. Detect the current air volume of the large flue.

52. Calculate the difference between the current air volume of the large flue and the target air volume of the large flue. 53, determining whether the difference is greater than or equal to the set threshold, if the difference is greater than or equal to the set threshold, then executing S105, otherwise, performing step S4;

54. Adjusting the opening degree of the bellows valve so that the effective air volume of the large flue is equal to the effective air volume of the large flue target air volume before the bellows valve is adjusted.

In the sintering system, the effectiveness of the air volume decreases as the air volume increases, and vice versa as the air volume decreases. For example, the resistance of the layer is smaller and smaller as the duration of the sintering process is longer, and the reduction in the resistance of the layer causes the air volume passing through the layer to become larger and larger, and the effective air volume involved in sintering (ie, the oxygen contained in the wind) It is less and less, and the corresponding air volume effectiveness is getting smaller and smaller. At this time, by adjusting the bellows valve opening degree (closed) and appropriately increasing the bellows negative pressure, it is beneficial to maintain the effective air volume.

The function of step S3 is to determine the magnitude of the change of the load, to determine whether to adjust the main exhaust fan or adjust the opening degree of the bellows valve, or to determine the selection of the adjusting means, so that the adjustment of the bellows valve is replaced by the adjustment of the bellows valve when the load changes little. The adjustment of the blower is such that the effect of the adjustment on the sintering system is as small as possible.

The function of step S4 is to determine whether the opening of the bellows valve becomes larger or smaller. When the target flue volume of the large flue is obtained, it indicates that the change of the load requires the system to provide an effective air volume corresponding to the target flue volume of the large flue, and the effective air volume can be calculated before the bellows valve is adjusted, that is, the current bellows valve state, that is, The current effective wind rate is multiplied by the target volume of the large flue. Therefore, the goal of the bellows valve opening adjustment is to make the effective flue volume of the large flue equal to the effective air volume of the large flue target air volume before the bellows valve is adjusted. Among them, the effective flue volume of the large flue can be obtained by the effective flue rate calculation by detecting the large flue volume. Since the person skilled in the art can implement the solution according to the instructions of the embodiment, it will not be described again. Embodiment 2

In the control method provided by the embodiment, the target flue volume of the large flue is obtained by using the obtained amount of the sintered material, and the frequency of the main exhaust fan is adjusted by using the corresponding relationship between the large flue air volume and the main exhaust fan speed. Since the amount of sintered material is generally obtained by means of detection and the like, the accuracy of obtaining the amount of sintered material is an important factor affecting the adjustment effect of the main exhaust fan. FIG. 3 shows a flow chart of a method for controlling the frequency conversion of the main exhaust fan of the sintering system provided in the second embodiment. Follow Figure 3:

5201. Detect the flow rate of all fabric outlet materials.

The flow rate of all fabric outlet materials is continuously or periodically detected, that is, the amount of material at all fabric outlets of the fabric machine per unit time is detected. In this step, the material flow rate of all the fabric outlets of the distributing machine is continuously or periodically detected to realize continuous and multiple inspections of all the fabric outlets of the distributing machine for the calculation of the subsequent sintering material amount.

5202. Accumulate the average value of all fabric outlet material flows.

That is, the average material flow rate of each fabric outlet detected in step S201 is averaged, and then the average value of the material flow rates of all the fabric outlets is accumulated.

5203. Calculate the amount of sintered material.

The calculation of the amount of the sintered material is calculated based on the result of the accumulation in step S202, and the above accumulated result is multiplied as the amount of the sintered material.

Among them, the continuous detection is to continuously collect the material flow rate of all the fabric outlets at a small time interval in a specific time period, which is suitable for the material flow detection under the condition that the material flow fluctuation of the fabric outlet is caused by the equipment. The length of this particular time period is dynamically adjusted with the state of the device, and the time interval is preset according to the actual situation. For example, the time interval can be set to 1 second, 1.5 seconds or 2 seconds. When the material flow rate of the fabric outlet is collected at this time interval, if the fluctuation of the material flow rate of a fabric outlet collected is more than a set percentage, such as 5%, the cloth flow is prolonged. Time, until the collection time is greater than or equal to the adjusted limit value, or the accumulated material flow collection time is greater than or equal to the adjusted limit value, or the material flow fluctuations of all the fabric outlets collected three times in succession are less than the set percentage. The adjusted limit is an empirical value, such as 20 seconds.

This particular time period is actually the execution cycle of step S203. At the end of the time, the amount of sintered material is calculated once, and the subsequent steps are further performed to complete an adjustment.

The periodic detection is that the material flow of all the fabric outlets is continuously collected at a large time interval in a certain period of time, which is suitable for the condition of the equipment to be stable, and the fluctuation of the cloth flow is less than the allowable value. Material flow detection under. Therefore, the specific time period of periodic detection is usually long, for example, 300 seconds, and the time interval is also large, for example, 5 seconds or 10 seconds.

In another embodiment, the method of periodic detection is firstly adopted. If the fluctuation of the material flow rate of a certain cloth outlet collected twice is greater than a set percentage, the continuous detection mode is started, so that the material flow detection is more realistic. The situation is beneficial to the timely adjustment of the system, and is conducive to the stable operation of the system equipment.

Another example of collecting material flow changes is described with reference to the third embodiment shown in FIG.

In the second embodiment, the steps 204-208 correspond to the steps S102-106 in the first embodiment, and details are not described herein.

Compared with the first embodiment, the sintering system main exhaust fan frequency conversion control method provided in the second embodiment provides a more optimized method for obtaining the amount of sintered material, and continuously or periodically detects the material flow rate of all the fabric outlets of the distributing machine, that is, The amount of material in all fabric outlets per unit time, and then the average of the continuous or periodic detection results is accumulated, and the accumulated amount is used to calculate the amount of sintered material. In this way, by measuring the amount of the sintered material by multiple measurements and using the average of multiple measurements, the measurement error can be reduced, and the accuracy of the obtained sintered material amount can be improved. In addition, the program detects the material flow rate of the cloth outlet of the distributing machine, that is, the detection at the source of the material conveying, and can obtain the most realistic amount of sintering material in time, and reduce the adjustment lag caused by the hysteresis of the value obtained.

In another embodiment based on the second embodiment, specifically, between steps S206 and S207 of the second embodiment, the following steps are further included:

Sl. Detect the current air volume of the large flue.

52. Calculate the difference between the current air volume of the large flue and the target air volume of the large flue.

53. Determine whether the difference is greater than or equal to a set threshold. If the difference is greater than or equal to a set threshold, perform S207; otherwise, perform step S4.

54. Adjusting the opening degree of the bellows valve so that the effective air volume of the large flue is equal to the effective air volume of the large flue target air volume before the adjustment of the bellows valve. Embodiment 3 During the process of obtaining the amount of sintered material, the fluctuation of the amount of sintered material has uncertainty, such as the fluctuation time and the amplitude of fluctuation.

To this end, the third embodiment optimizes the second embodiment. Referring to FIG. 4, the figure shows the flow of the frequency conversion control method of the main exhaust fan of the sintering system provided in the third embodiment.

In this embodiment, steps S301-S302 are equivalent to steps S201-S202 in the second embodiment, and the steps are

S304 is equivalent to step S203 in the second embodiment. However, the following steps are further included between step S302 and step S304:

Step S303: Determine whether the adjacent two accumulated difference values are within a set range. If yes, go to step S304, which means that the material flow fluctuation of the cloth outlet of the whole cloth machine is small, and the amount of sintered material is relatively stable, which can be used as an initial parameter; otherwise, the process goes to step S302.

Steps S304 to S309 correspond to S203 to S208 in the second embodiment. For the corresponding part, refer to the content in the second embodiment, and details are not described herein.

According to the third embodiment, there is a preliminary judgment on the material flow stability of the cloth outlet of the cloth machine, and then the corresponding operation is performed according to the judgment result, so that the data is detected under the premise that the material flow rate of the cloth outlet of the cloth machine is relatively stable, and the sintering can be improved. The accuracy of the material quantity.

In another embodiment, a determining step is further included between step S302 and step S303, if the accumulated material flow collection time is greater than or equal to the adjusted limit value, or the material flow fluctuations of all the fabric outlets of the distributing machine are collected three times in succession. If it is less than the set percentage, the process goes to step S304; otherwise, the process goes to step S303.

In another embodiment based on the third embodiment, specifically, between steps S307 and S308 of the third embodiment, the following steps are further included:

51. Detecting the current air volume of the large flue;

52. Calculate the difference between the current air volume of the large flue and the target air volume of the large flue;

53, determining whether the difference is greater than or equal to a set threshold, if the difference is greater than or equal to the set threshold, then executing S308, otherwise, performing step S4;

54. Adjusting the opening degree of the bellows valve so that the effective air volume of the large flue is equal to the effective air volume of the large flue target air volume before the adjustment of the bellows valve. Implementation four

In the second embodiment and the third embodiment, the material flow rate is obtained at the cloth outlet of the distributing machine to calculate the amount of the sintered material. For the sintering system for the production of specific materials, the distance N of the pre-set sintering end point from the starting position of the sintering is known, and the sintering trolley width and the sintered material density p are known, so the thickness of the material layer on the sintering trolley is detected! ! Material ^ and sintering trolley speed V^, calculate the amount of burnt material by formula (1). For a specific operation process, please refer to FIG. 5, which shows a flow chart of a frequency conversion control method for a main exhaust fan of a sintering system according to Embodiment 4 of the present invention.

The process shown in Figure 5 includes:

S401, detecting the thickness of the layer and the speed of the sintering trolley.

S402. Calculate the amount of the sintered material.

The amount of the sintered material was calculated according to the formula (1) in the first embodiment.

In this embodiment, the steps S403 to S407 correspond to S102 to S106 in the first embodiment, and details are not described herein. The control method provided in this embodiment calculates the amount of sintered material by detecting the thickness of the material layer and the speed of the sintering trolley.

In order to make the detection result more accurate, preferably, in the above step S401, the thickness of the material layer of the corresponding portion of the sintering trolley and the cloth outlet of the distributing machine is detected. The thickness of the layer at this part can directly reflect the latest changes in the amount of sintered material, and the detection of the part can realize the adjustment of the subsequent steps in time, and finally realize the more timely and accurate adjustment of the frequency value of the main exhaust fan.

In another embodiment based on the fourth embodiment, specifically, between steps S405 and S406 of the fourth embodiment, the following steps are further included:

51. Detect the current air volume of the large flue.

53. Determine whether the difference is greater than or equal to a set threshold. If the difference is greater than or equal to the set threshold, execute S406. Otherwise, perform step S4.

54. Adjusting the opening degree of the bellows valve so that the effective air volume of the large flue is equal to the effective air volume of the large flue target air volume before the adjustment of the bellows valve. Embodiment 5

In this embodiment, by using the correspondence relationship between the large flue air volume and the main exhaust fan speed, the target blower target speed corresponding to the large flue target air volume is searched, and the current frequency of the main exhaust fan is adjusted to the main blower target speed. The target frequency of the extractor. In the actual adjustment process, in order to ensure the smooth operation of the equipment, try to avoid the large adjustment of the power of the equipment. This embodiment is improved on the basis of the foregoing embodiment. Referring to FIG. 6, FIG. 6 shows a flow of a control method provided in Embodiment 5 of the present invention. The steps S501 to S505 correspond to the steps S101 to S105, and are not described here. The steps S506 to S508 are implemented as follows:

S506. Determine whether a difference between the target speed of the main blower and the current speed of the main blower is greater than a set value. If yes, go to step S508; otherwise, go to step S507.

5507. Adjust the current frequency of the main exhaust fan to the target frequency of the main exhaust fan corresponding to the target speed of the main exhaust fan.

5508. Set the adjustment interval to adjust the current frequency of the main exhaust fan, and go to step S506.

In the above manner, when the difference between the target speed of the main exhaust fan and the current speed of the main exhaust fan is greater than the set value, in order to avoid the influence of the large power adjustment of the device on other devices of the system, the main exhaust fan needs to be adjusted according to the set adjustment interval. The current frequency is adjusted, for example, by 1 Hz as an adjustment interval until the difference between the adjusted main exhaust fan frequency and the main blower target speed corresponding to the main blower target speed is less than the set value, and finally the The adjusted main exhaust fan frequency value is adjusted to the target frequency of the main exhaust fan corresponding to the target speed of the main exhaust fan. Of course, if the pitch is adjusted by 1 Hz, the setting should be less than 1 Hz.

In another embodiment based on the fifth embodiment, specifically, between steps S504 and S505 of the fifth embodiment, the following steps are further included:

Sl. Detect the current air volume of the large flue.

S2. Calculate the difference between the current air volume of the large flue and the target air volume of the large flue.

S3. Determine whether the difference is greater than or equal to a set threshold. If the difference is greater than or equal to the set threshold, execute S505. Otherwise, perform step S4. S4. Adjusting the opening degree of the bellows valve so that the effective air volume of the large flue is equal to the effective air volume of the large flue target air volume before the adjustment of the bellows valve. Embodiment 6

Based on the first embodiment, the sixth embodiment provides a frequency conversion control system for the main blower of the sintering machine. Please refer to FIG. 7, and the system shown in FIG. 7 includes:

The initial parameter obtaining unit 601 is configured to obtain the amount of the sintered material. The amount of the sintered material may be a value set in advance according to the production schedule, or may be a detected value detected by the detecting device.

The first calculating unit 602 is configured to calculate the vertical sintering speed of the material layer by using the amount of the sintered material and the preset sintering end point, and calculate the effective air volume of the large flue using the relationship between the vertical sintering speed and the effective air volume.

The calculation process of the first calculating unit 602 is as follows:

First, the amount of the sintered material per unit time is calculated by the formula (1) in the first embodiment.

Next, the vertical sintering speed of the layer was calculated by the formula (5) in the first embodiment.

Again. Calculate the effective air volume of the large flue using the formula (6) in the first example:

The smoke component detecting unit 603 is configured to detect a large flue gas component of the sintering system. The smoke analyzer set in the specific control or operating system detects the smoke component to calculate the effective wind rate. The flue gas components of the large flue can be directly detected in the large flue, or can be calculated by detecting the flue gas components of each bellows.

The second calculating unit 604 is configured to calculate the effective wind rate by using the large flue gas component, and calculate the large flue target air volume by dividing the large flue target air volume by the large flue effective air volume by the effective wind rate.

The calculation process of the second calculating unit 604 is as follows:

First, the effective wind ratio is calculated by the formula (7) in the first embodiment.

Next, the target flue volume of the large flue is calculated by the formula (8) in the first embodiment.

The target parameter obtaining unit 605 is configured to use the corresponding relationship between the large flue air volume and the main exhaust fan speed to find the target blower target speed corresponding to the large flue target air volume.

a controller 606, configured to adjust a current frequency of the main exhaust fan to a target speed of the main exhaust fan The main extractor target frequency.

For the calculation process of each calculation module of the above control system, refer to the description in the first embodiment. For the beneficial effects of the control system, please refer to the beneficial effects of the method part, and details are not described herein.

In other embodiments based on the sixth embodiment, between the second calculating unit 604 and the target parameter obtaining unit 605, the following units (not shown in Fig. 7) are further included.

An air volume measuring unit for detecting the current air volume of the large flue.

The determining unit calculates a difference between the current air volume of the large flue and the target air volume of the large flue, and determines whether the difference is greater than or equal to a set threshold, and if the difference is greater than or equal to the set threshold, indicating the target parameter The obtaining unit 605 searches for the main blower target rotational speed corresponding to the large flue target air volume. Otherwise, the indication controller 606 adjusts the opening degree of the bellows valve so that the large flue effective air volume is equal to the large flue target air volume before the bellows valve adjustment. Effective air volume.

The controller in this embodiment has changed from the controller 606 in the sixth embodiment. Example 7

This embodiment is improved on the basis of the sixth embodiment. Referring to Figure 8, the initial parameter acquisition unit includes:

The material flow detecting subunit 701 is configured to continuously or periodically detect the material flow rate of all the fabric outlets of the distributing machine, that is, continuously or periodically detect the material quantity of all the fabric outlets of the distributing machine per unit time.

The material flow calculation sub-unit 702 is configured to accumulate the mean value of all the fabric outlet material flows obtained by the detection, and calculate the amount of the sintered material according to the accumulated result.

The first calculating unit 703, the smoke component detecting unit 704, the second calculating unit 705, the target parameter obtaining unit 706, and the controller 707 are respectively the first calculating unit 603 and the smoke component detecting unit 604 in the sixth embodiment. The second calculating unit 605, the target parameter obtaining unit 606, and the controller 607 are corresponding to each other and have the same functions, and are not described herein again.

The system of the present embodiment accumulates the amount of material of all fabric outlets per unit time continuously or periodically, and accumulates the average value of continuous or periodic detection results of all fabric outlets. The amount of sintered material is calculated based on the accumulated result. In this way, the amount of sintered material is determined by multiple measurements and the average value of multiple measurements, which can reduce the measurement error and improve the accuracy of the amount of sintered material.

In addition, the scheme detects the material flow rate of the cloth outlet of the distributing machine, that is, the material at the source of the conveying, and can obtain the most realistic amount of sintering material in time, and reduce the adjustment lag caused by the hysteresis of the numerical value.

In other embodiments based on the seventh embodiment, between the second calculating unit 705 and the target parameter obtaining unit 706, the following unit (not shown in Fig. 7) is further included.

The determining unit calculates a difference between the current air volume of the large flue and the target air volume of the large flue, and determines whether the difference is greater than or equal to a set threshold, and if the difference is greater than or equal to the set threshold, indicating the target parameter The obtaining unit 706 searches for the target speed of the main blower corresponding to the target air volume of the large flue, otherwise, the controller 707 adjusts the opening degree of the bellows valve so that the effective flue volume of the large flue is equal to the target flue volume of the large flue before the bellows valve is adjusted. Effective air volume.

The controller 707 in this embodiment has changed from the controller 707 in the seventh embodiment. Example eight

The embodiment of the present invention is improved on the basis of the sixth and seventh embodiments. Referring to FIG. 9, the initial parameter obtaining unit includes:

a material layer thickness detecting subunit 802, configured to detect a thickness of a layer of a portion opposite to an exit position of the sintering trolley and the distributing machine;

a sintering trolley speed detecting subunit 801 for detecting the speed of the sintering trolley;

The sintered material amount calculation sub-unit 803 is used for calculating the amount of sintered material, wherein the amount of sintered material = the width of the sintering trolley * the speed of the sintering trolley * the density of the sintered material * the thickness of the layer.

The first calculating unit 804, the smoke component detecting unit 805, the second calculating unit 806, the target parameter obtaining unit 807, and the controller 808 are respectively the first calculating unit 603 and the smoke component detecting unit 604 in the sixth embodiment. Second calculation unit 605, target parameter acquisition unit 606 and controller 607 - Corresponding, and the same function.

The control system according to this embodiment detects the thickness of the layer of the corresponding portion of the cloth exit of the sintering cart and the distributing machine. The thickness of the layer at this part can directly reflect the latest change of the amount of sintered material, and the detection of the part can realize the adjustment of the subsequent module in time, and finally realize the more timely and accurate adjustment of the frequency value of the main exhaust fan.

In other embodiments based on the eighth embodiment, between the second calculating unit 806 and the target parameter obtaining unit 807, the following unit (not shown in Fig. 7) is further included.

a determining unit, calculating a difference between a current air volume of the large flue and a target air volume of the large flue, and determining whether the difference is greater than or equal to a set threshold, and indicating the target if the difference is greater than or equal to the set threshold The parameter obtaining unit 807 searches for the target speed of the main blower corresponding to the target air volume of the large flue, and does not indicate that the controller 808 adjusts the opening degree of the bellows valve so that the effective air volume of the large flue is equal to the target air volume of the large flue in the bellows. The effective air volume before the valve is adjusted.

The controller in this embodiment has changed from the controller 808 in the eighth embodiment. The amount of sintered material described in the first to eighth embodiments of the present invention refers to the amount of sintered material processed by the sintering system per unit time, and the unit thereof is p屯 / time. It can be the amount of material sintered in the sintering system per hour, in units of p屯 / hour; it can also be the amount of sintered material per day in units of p屯 / day. The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments are obvious to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded to the broadest scope of the principles and novel features disclosed herein.

Claims

Rights request

1. The frequency conversion control method of the main exhaust fan of the sintering system is characterized by including the following steps:

1) Obtain the amount of sintering materials;

2) Use the amount of sintering material and the preset sintering end point to calculate the vertical sintering speed of the material layer, and use the relationship between the vertical sintering speed and the effective air volume to calculate the effective air volume of the large flue;

3) Detect the smoke components of the large flue;

4) Calculate the effective air rate using the smoke components of the large flue, and calculate the target air volume of the large flue, where the target air volume of the large flue is equal to the effective air volume of the large flue divided by the effective air rate;

5) Use the corresponding relationship between the large flue air volume and the main exhaust fan speed to find the main exhaust fan target speed corresponding to the large flue target air volume;

6) Adjust the current frequency of the main exhaust fan to the target frequency of the main exhaust fan corresponding to the target speed of the large flue.

2. The method according to claim 1, characterized in that the amount of sintering material is obtained in the following way:

21) Continuously or periodically detect the material flow rate of all cloth outlets of the cloth machine;

22) The mean value of all fabric outlet material flow rates detected cumulatively;

23) Calculate the amount of sintering material based on the cumulative results.

3. The method according to claim 2, characterized in that, between steps 22) and 23), it also includes: judging whether the difference between two adjacent accumulation results is within a set range, and if so, go to step 23 ); Otherwise, go to step 22).

4. The method according to claim 1, characterized in that, the amount of sintering material is obtained in the following way: detecting the thickness of the material layer and the speed of the sintering trolley at the corresponding parts of the sintering trolley and the cloth outlet of the distribution machine, and calculating the sintering material in the following way. quantity:

The amount of sintering material = the width of the sintering trolley * the speed of the sintering trolley * the density of the sintering material * the thickness of the material layer.

5. The method according to claim 1, characterized in that:

Detect the smoke components of each bellows;

6. The method according to claim 5, characterized in that: periodically detecting the flue gas of each bellows

7. The method according to claim 1, characterized in that, between step 5) and step 6), it also includes:

71) Determine whether the difference between the target speed of the main exhaust fan and the current speed of the main exhaust fan is greater than the set value. If so, go to step 72); otherwise, go to step 6);

72) Use the set adjustment interval to adjust the current frequency of the main exhaust fan to the target frequency of the main exhaust fan corresponding to the target speed of the main exhaust fan, and go to step 71).

8. The method according to claim 1, 2, 3, 4, 5, 6 or 7, further comprising: detecting the current air volume of the large flue;

If the difference is greater than or equal to the set threshold, adjust the current frequency of the main exhaust fan to the target frequency of the main exhaust fan corresponding to the target air volume of the large flue. Otherwise, adjust the opening of the air box valve to make the effective air volume of the large flue It is equal to the effective air volume of the large flue target air volume before the bellows valve is adjusted.

9. The sintering system main exhaust fan frequency conversion control system is characterized by including:

Initial parameter acquisition unit, used to obtain the amount of sintering material;

The first calculation unit is used to calculate the vertical sintering speed of the material layer using the amount of sintering material and the preset sintering end point, and to calculate the effective air volume of the large flue using the relationship between the vertical sintering speed and the effective air volume; the flue gas component detection unit, Used to detect flue gas components in the large flue of sintering systems;

The second calculation unit is used to calculate the effective air rate using the smoke components of the large flue, and calculate the target air volume of the large flue by using the target air volume of the large flue equal to the effective air volume of the large flue divided by the effective wind rate;

The target parameter acquisition unit is used to use the corresponding relationship between the large flue air volume and the main exhaust fan speed to find the main exhaust fan target speed corresponding to the large flue target air volume;

A controller used to adjust the current frequency of the main exhaust fan to the target frequency of the main exhaust fan corresponding to the target speed.

10. The system according to claim 9, characterized in that the initial parameter acquisition unit includes:

The material flow detection subunit is used to continuously or periodically detect the material flow of all cloth outlets of the cloth machine; The material flow calculation subunit is used to accumulate the average value of all cloth outlet material flow rates detected and calculate the amount of sintering material based on the accumulation results.