JPS6154450B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method of operating a dust collection system that centrally collects dust-containing gas generated at a plurality of locations. As a dust collection system that centrally collects dust-containing gases generated at multiple locations, in the steel industry, this system is called castbed dust collection, which centrally collects dust-containing gases generated from around the cast bed of a blast furnace. The dust-containing gas generated at multiple locations such as the taphole of the blast furnace, the hot metal, the slag trough, the hot metal dropping port to the torpedo car, etc., is concentrated by installing dust collection ports at each generation source. are removed by suction. Of these dust-containing gases, the amount of dust-containing gas generated at the taphole varies greatly depending on the opening of the taphole, the initial stage of tapping, the final stage of tapping, and when the taphole is closed. By the way, in the case of typical foundry dust collection in the past, the dust collection capacity was adjusted to the maximum value of the amount of dust-containing gas generated, and the dust-containing gas was suctioned and removed at the maximum suction air volume during the above-mentioned tapping state. After that, the applicant filed a patent application in 1983.
- No. 92091 improves the conventional operation method of casting bed dust collection, and improves the dust collection system by controlling the rotation speed of the dust collection blower or the branch pipe damper installed at each dust collection port in the dust collection system. I suggested a driving method, but
Due to the complexity of fluctuations in the amount of dust-containing gas generated in the above-mentioned tapping state and fluctuations in dust-containing gas due to the opening of the taphole, the control becomes complicated, and it is difficult to collect dust in a sufficiently effective and energy-saving manner. I haven't reached it yet. In the case of inlet damper control, in order to perform accurate air volume control in blast furnace cast bed dust collectors, in order to capture the complex changes in the amount of dust generated in the blast furnace cast bed, in the case of inlet damper control, the standard of the inlet damper opening degree or the rotation speed control. In some cases, a standard for the rotation speed of the dust collection blower is required. Conventionally, the following methods have been adopted as a method for inputting this criterion, but each of these methods has the following drawbacks. (1) A method of manually inputting criteria (operator setting). The standard setting is inaccurate and subjective, there is a risk of setting an excessive air volume or forgetting the setting, and the manual operation described above is time-consuming. (2) A method of creating standards based on dust amount sensor information. The dust amount sensor is expensive, has low reliability, and has a fatal flaw in that it causes a detection delay. In other words, according to this method, since the air volume is controlled after determining the amount of dust particles, the control is inevitably delayed. (3) A method in which several types of dust collection dampers are uniformly set in advance using a timer, etc. according to the tapping situation, and standards are created by selecting these several types of patterns. According to this method, air volume control inevitably becomes rough due to fluctuations in operating conditions, resulting in insufficient or excessive air volume. (4) A method that incorporates various information factors that determine the appropriate air volume, and uses a combination of these information to perform digital calculation processing to determine the appropriate air volume under all circumstances. According to this method, very high accuracy can be obtained, but the disadvantage is that the computation becomes large and the arithmetic and control device becomes expensive. An object of the present invention is to provide a method for operating a dust collection system that eliminates and improves each of the drawbacks of the conventional methods described above, and achieves the above object by providing the method described in the claims. be able to. That is, the present invention provides a method for operating a dust collection system in which dust-containing gas generated at multiple locations is sent to a dust collector via a dust collection port, a branch pipe, a branch pipe damper, a main pipe, and a dust collection blower. The opening degree of the branch pipe damper is determined based on the amount of generated dust, and a control value that takes into account the damper opening degree and the pressure loss within the branch pipe at that opening is determined for each branch pipe, and the opening/opening of the branch pipe damper is The rotation speed of the dust collection blower is controlled from the aggregate control value of each damper based on the closing signal, and the rotation speed is controlled using the number of opening/closing dampers of the branch pipe damper and operation information as control factors for the aggregate control value. The present invention relates to a method of operating a dust collection system that centrally collects dust-containing gas generated at a plurality of locations, the method further comprising adjusting: Next, the present invention will be explained in detail. The present inventors have developed a dust collection system by controlling the rotation speed of the dust collection blower of the dust collection system, which can obtain results comparable to digital calculation processing using analog calculation processing technology that adds analog values to various information factors. The present invention was completed by coming up with an operating method. The reference input calculation for controlling the air volume by controlling the rotational speed of the main blower of a cast bed dust collector of a blast furnace to which the present invention is specifically applied will be described below as an example. Changes in the amount of dust generated in the casthouse generally follow the time course shown in FIG. That is, the dust generation increases with the start of tapping by opening the tap hole, and as the hot metal flows down in the gutter, the dust generation area gradually expands. During the middle stage of pig iron tapping, the dust generation state is almost constant, but as the slag ratio increases, the amount of dust generation gradually increases again, and then at the end of the pig iron tapping stage, the dust generation suddenly increases due to blockage of the mazdogan. and reaches its peak. After the tap hole is closed, the dust generation quickly subsides, and only a small amount of dust is generated during residual pig iron disposal and maintenance work. The process described above is repeated from each tap to the next tap. In order to collect more than one amount of dust, a smoke collection duct is routed through the casthouse dust collector blower into the casthouse building, and end dampers are installed at each dust generation point branching off from these ducts. These dampers are opened and closed depending on the amount of smoke collected. FIG. 2 is a diagram showing an example of the arrangement of the smoke collection duct and end damper of the cast bed dust collector, and the dust collection duct branch pipe branched from the dust collection duct main pipe 2 of the dust collection blower 1 has a branch pipe damper ( These dampers (hereinafter referred to as end dampers) 3-1 _{to 3-4} are provided. Note that the ▽ mark at the end of the branch pipe in the figure is the dust collection port. The blast furnace main body 6 is provided with four tap holes, and dust collection hoods 7-1 to _7-4 are respectively arranged above each tap hole, and the tap hole, tap/slag tap hole, Each torpedo car dropout port is equipped with a dust collection port. In the above dust collection system, the cast bed dust collector blower 1
The appropriate amount of air that should be inhaled basically changes from moment to moment, so it must be made to follow changes in the amount of dust generated when the iron is not tapped, when a single tap is tapped, or when two taps are tapped at the same time. In addition to this, it is also necessary to consider changes in pressure drop in the system from the cast bed dust collector blower to the end damper via the smoke collection duct. The pressure drop in the above system varies depending on which end damper is opened and the number of end dampers that are opened. For example, if the casting bed dust collector blower, smoke collection duct, and end damper are arranged as shown in Figure 2, then the 2TH which is far from the dust collector blower, as shown in Figure 3,
(TH is an abbreviation for Tap Hole.)
There is a big difference in pressure drop when the end damper _3-2 of the 2TH system is opened during tapping, and when the end damper _3-4 of the 4TH system is opened during 4TH tapping, which is close to the dust collection blower. In other words, the pressure drop will be smaller in the 4TH system, which is closer to the dust collection blower. Therefore, to obtain the same air volume Q, the 2TH system requires a rotation speed of Q/Q ₂ , as shown in Figure 3, but the 4TH system requires a rotation speed of Q/Q ₄ ,
In other words, the number of rotations is smaller than the number of rotations of Q/Q ₂ . Therefore, in order to determine the appropriate rotational speed of the blower of the casthouse dust collector, it is important to understand not only the change in the amount of dust generated from time to time, but also the change in pressure drop in each branch pipe. According to the present invention, a means is employed for determining these changes by representing the opening/closing signals of the end dampers disposed in the foundry building. That is, the end dampers are sequentially opened as the amount of dust generated or the location of dust generation changes. Therefore, by taking in the number of these open end dampers and information for each open end damper, it is possible to estimate the change in the amount of dust generation and the change in the pressure drop. According to the present invention, in addition to the damper opening degree determined based on the amount of dust generated by all end dampers, an analog value is added that is a relative ratio in proportion to the pressure drop from the blower to each end damper, and each By determining a control value for each end damper, the end damper opening signal is used to use the control value of the end damper to control the rotation speed of the dust collecting blower. In other words, each end damper control value can be said to be an index converted into a rotational speed ratio for obtaining the suction air volume necessary for dust collection by each end damper. Therefore, by detecting the end dampers that are open and simply summing up the control value of each end damper, that is, the analog value converted into a rotation speed ratio, from time to time, it is possible to control the rotation speed of the blower using this value. , it is possible to determine the appropriate rotation speed of the dust collection blower in any situation. However, if this method is simply adopted, two contradictions will arise; one is that if the end damper of a TH system that is not tapped is opened for another purpose, such as maintenance work such as gutter repair, etc. It is not necessary to secure the required air volume for these terminal dampers, but the necessary air volume is secured only for the tapping TH system terminal damper, and the remaining amount determined by this is transferred to the above TH system terminal damper that is not tapping. You have to perform an operation to sort them out. This is because the analog value converted into a rotational speed ratio is a value for obtaining the required air volume when tapping, so a smaller value is sufficient when not tapping. For example, in the arrangement shown in Figure 3, if some of the end dampers of the 2TH system are opened when the 4TH is tapping, the rotational speed will be higher than necessary just by counting. From this, it is possible to lower the rotation speed until the end damper of the 4TH system can obtain the required air volume during tapping. Another contradiction arises in that the analog relative value converted into a rotational speed ratio does not satisfy the entire range of changes in pressure loss due to changes in the number of open end dampers. In other words, as the end dampers are opened more and more, the pressure drop in the system becomes smaller and the resistance curve falls. Therefore, simply counting the analog values of the open end dampers will result in an excessive air flow than necessary, and conversely, the number of open end dampers will increase. If it is abnormally low, the pressure drop in the system will increase and the resistance curve will rise, so if you simply tally up the analog values of only the open end dampers, the air volume will be less than necessary. This phenomenon occurs because the analog values of each end damper are distributed based on the assumption that the resistance curve of the system is constant. In order to solve the above two contradictions, according to the present invention, in addition to the above-mentioned air volume control, operational information of the dust generation location, that is, the tapping status of the taphole in the case of casting bed dust collection, is captured and the information is collected. Depending on the situation, the analog correction value is added to the total analog value of each opening end damper to perform the correction all at once. For example, in a situation where 2TH is tapped, the 2TH system end damper is opened, and more than a certain number of 3TH system end dampers are opened, the corresponding damper A measure is taken of adding a positive or negative analog value as a correction value to the numerical aperture and operation information and then tabulating the values. In setting the number of situations of the above-mentioned tapping situation, it is sufficient to prepare in advance an example of a situation that may occur and determine the above-mentioned correction value, and then deal with the example of the situation in detail. The more examples of situations there are, the more detailed the calculations will be, but when it comes to dust collection from a blast furnace cast bed, preparing several types of correction values and selecting one of these correction values will ensure sufficient practical handling. I found out that it can be done. According to one embodiment of the present invention, the above situation examples can be aggregated into 18 situations and can be handled by selecting 6 types of preset correction values for each situation. The situation is shown in the table below.

【table】

[Table] (18) No tapping → Unconditionally minimum speed By the way, the tapping status is determined by the drive signal of the front machinery such as the matsudo gun, hole drill, splash cover, etc., the hot mass detector (hereinafter referred to as HMD), and the dust Since it is only necessary to logically determine the tapping situation in the casthouse based on the tapping information such as a sensor signal from a meter or the like, according to the present invention, the tapping situation is determined according to this judgment. For example, if the hole puncher is in operation, dust is expected to be generated when drilling the hole as shown in Figure 1, and if the evacuation signal for the splash cover is obtained, it will be possible to detect the blockage point and also to evacuate all of the muzzle gun, the hole drill, and the splash cover. If so, the suction air volume is smaller than the air volume during operation, rather than suction operation of dust-containing gas that accompanies the operation of the dust generating area, and it can be determined that the air volume is for work such as clearing the cast bed, and the rotation speed of the dust collection blower. can be reduced. FIG. 4 shows a simplified circuit diagram of one blown air volume calculation and control device used to carry out the method of the present invention. In the figure, the calculations are 1TH system, 2TH system,
It is divided into an addition operation for each opening end damper group unit of the 3TH system and 4TH system, an addition operation of correction values, and a final addition operation thereof. The analog value imposed on each signal can be easily set and varied by adjusting the volume, such as 1RH, for example.
In addition, in the final addition calculation, it is possible to adjust the overall bias setting using 2RH or the overall magnification setting using 3RH. Note that the damper opening standard in power-saving operation using inlet damper control can also be handled by calculation control based on the same concept as above. According to the present invention, it is possible to easily and automatically calculate and supply a criterion for determining an appropriate suction air volume in suction air volume control for the purpose of power saving of a blast furnace casthouse dust collector. Note that the present invention is not only a blast furnace cast bed dust collector.
It can be applied to standards for appropriate suction air volume for dust collectors in which many information factors such as end dampers control the air volume drawn in. As described above, according to the present invention, when sucking dust-containing gas, it is possible to set an appropriate dust-collecting blower rotation speed based on the dust-collecting suction air volume and pressure loss in the pipe, and to suction the dust-containing gas extremely efficiently. It becomes possible.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between temporal changes in the blast furnace tapping situation and changes in the amount of dust generated, Figure 2 is a layout diagram of one of the smoke collection ducts and end dampers of the blast furnace casthouse dust collector, and Figure 3
The figure is an explanatory diagram showing changes in the resistance curve due to differences in the length of the smoke collection duct, and FIG. 4 is a simplified circuit diagram of the suction air volume calculation and control device. 1...Castbed dust collector main blower, 2...Smoke collection duct, 3 _-1 ...1TH series end damper, 3 _-2 ...2TH
System end damper, 3 _-3 ...3TH system end damper, 3 _-4
... 4TH system end damper, 5 ... Blast furnace cast bed dust collector, 6 ... Blast furnace body, 7 _-1 ... 1TH taphole, 7 _-2
...2TH taphole, 7 _-3 ...3TH taphole, 7 _-4 ...
4TH taphole.

Claims (1)

[Claims] 1. In the operating method of a dust collection system that sends dust-containing gas generated at multiple locations to a dust collector via a dust collection port, branch pipe, branch pipe damper, main pipe, and dust collection blower, The opening degree of the branch pipe damper is determined from the amount, and a control value that takes into account the damper opening degree and the pressure loss in the branch pipe at that opening degree is determined for each branch pipe, and based on the open/close signal of the branch pipe damper. The rotation speed of the dust collecting blower is controlled based on the aggregated control value of each damper, and the rotational speed is further adjusted using the number of opening/closing dampers of the branch pipe dampers and operation information as control factors for the aggregated control value. A method of operating a dust collection system that centrally collects dust-containing gas generated at multiple locations.