JPS5824197B2 - Fun Iki Kitaino Jiyouka Souchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for purifying atmospheric gas such as dust-containing gas, dust-containing air, combustion exhaust gas, and air containing noxious gases that are undesirable for hygiene. The goal is to reduce

In general, various industries generate various types of exhaust gases such as dust-containing gases and combustion exhaust gases that require purification during production processes.

Therefore, in order to purify the emissions and the air containing the emissions, various purification devices adapted to the type of emissions are used, such as dry or wet dust collectors, chemical reaction equipment that uses various cleaning solutions, neutralizing agents, etc. and devices that combine them are used.

In the present invention, the term "purifying device" is used in the above-mentioned sense.

However, the power required for the blower to suck in the above-mentioned atmospheric gas and send it to the purification device is extremely large because the above-mentioned atmospheric gas is extremely large in quantity, and this only contributes to high costs. First, there is a problem in that an enormous amount of fossil fuel is required to produce energy, such as electric power, to obtain the required power, which also increases combustion exhaust gas.

Therefore, although the purpose of purification is still achieved, as a result of researching a means that requires significantly less power, we found a combination of damper control in intake air amount control and blower rotation speed control, that is, drive motor rotation speed control. In addition to the above, since the amount of atmospheric gas that needs to be treated at each point of occurrence changes in the order of the process, we have developed a method that focuses on calculating the amount of intake air in advance and controlling the rotation speed using the results. This will be explained in more detail below with reference to the drawings.

Now, if we take converter equipment as an actual example, the production process is as shown in Figure 1: charging 1, blowing 2, temperature measurement sample collection 3,
The process progresses in the order of tapping 4 and waste slag 5, and the dust generation locations and the amount of generation at each dust generation location differ according to the order of the steps, and the same applies to the exhaust gas.

Conventionally, in the converter equipment, as shown in FIG. 2, intake branch pipes 8a to 8c having intake ports 6a to 6c and control dampers 7a to 7c, for example, are provided for each occurrence location, and furthermore, the intake branch pipes 8a to 8c are provided. 8c is connected to an intake main pipe 10 having a main damper 9, and is equipped to supply atmospheric gas to a purification device 13 for treatment via a blower 12 driven by a drive motor 11. The operator sequentially opens and closes an arbitrary number of the control dampers 7a to 7c, and at the same time adjusts the opening degree of the main damper 9 to control the intake air amount.

By the way, in the means of operating a control damper in adjusting the amount of intake air, it can be considered that the amount of intake air and the required power of the blower are approximately proportional to each other.

In other words, if the required power at the maximum intake air amount is 100%, when the intake air amount is reduced to 40%, the required power becomes 40%.

However, when the intake air amount is controlled by lowering the rotational speed of the blower drive motor, the required power required to increase the above-mentioned intake air amount to 40 units is only 8.5 to 17 units.

In other words, significant power savings can be achieved. The reason why the required power ranges from 8.5 to 17 is that the required power varies depending on the type of drive motor and the rotation speed control mechanism.

Now, Table 1 shows the difference between the above-mentioned intake air amount and required power.

Next, rotation speed control in the present invention will be explained in detail.

Now, in Fig. 3, if the generation locations R1, R2゜R3 are the pig iron receiving equipment, the furnace front work floor, and the slag equipment, the amount of atmospheric gas generated differs depending on the process, and the amount of atmospheric gas generated for each of them also changes as the work progresses. The amount generated increases or decreases.

Taking pig iron receiving pot equipment R1 as an example, before the start of pig iron receiving, at the beginning of pig iron receiving,
Since the amount of atmospheric gas generated differs in the middle, late, and final stages of pigtail receiving, if air was taken in at maximum capacity regardless of the work progress, the loss in required power would be large as described above.

Therefore, conventionally, a means has been adopted in which the operator adjusts the opening degree of the control damper 7a as the work progresses, but the present inventors have discovered that there is a fixed pattern for each process regarding the amount of intake air required as the work progresses. I realized that it was starting to become a stereotype.

Therefore, a work progress start signal, which is obtained as an operation command for dustproof cover operation or tilting of the pig iron mixer, or an operator's command, is used as an input signal to issue an opening adjustment command from the control device 16 according to a certain pattern. is given to the damper controller 14a, and the damper controller 14a is configured to operate the control damper 78 based on the command.

Next, a signal that detects the opening degree of the control damper 7a by an opening detection device 15a such as an instruction synchronizer is inputted to the arithmetic unit 17.

Similarly, for the occurrence locations R2 and R3, the control dampers 7b and 7c are operated as the work progresses, and the detection signals of the damper openings by the opening detection devices 15b and 15c are detected.
The information is input to the arithmetic unit 17.

Here, the required intake air amount of the blower is determined in accordance with the opening degrees of the control dampers 7a, 7b, and 7c, the rotation speed of the drive motor is calculated using the damper opening degrees as a parameter, and a rotation speed control command is given to the drive motor 11. is given to the motor control device 18.

As described above, the required intake air amount is determined in exactly the same manner for the occurrence locations R1, R2, R3 and other occurrence locations (not shown), and the drive motor 11 is controlled in accordance with the total intake air amount.

The pattern of the opening degree of the control damper 73 of the intake branch pipe 8a corresponding to the occurrence location R1 (hereinafter simply referred to as the control pattern) and the control damper 7b corresponding to the occurrence locations R2 and R3.
, 7c are naturally different, and the opening state often changes over time.

Therefore, the more finely the control of the intake air amount of the blower 12 or the rotational speed control of the drive motor 11 is performed in accordance with the arithmetic function and the responsiveness of the equipment, the less power is required.

In addition, since the motor rotation speed can be calculated in advance from the required intake air amount, the arithmetic unit 17
It is also possible to store a control value in advance and use it.

Now, even with such control, the required power can be significantly reduced, but as a result of searching for further improvement in efficiency, the opening degree detection devices 15a and 15b.

Input from 15c (in the figure, signals from 15a to 15c are input to the arithmetic unit 17 via input terminals 01 to C3)
It turns out that the method using ``is a bit of a loss when it comes to rapidly changing patterns because of the time delay.

Therefore, the control device 16 outputs the output terminal T1. At the same time, an opening adjustment command signal (hereinafter referred to as an opening signal) transmitted to the damper controllers 14a to 14C (in the present invention, the damper controllers 14a to 14c are used as a control device) via T3 is sent to the arithmetic device 17. The required motor rotational speed is determined and controlled as described above, and the opening signals from the opening detection devices 15a to 15c are used to confirm the opening of the control dampers 7a to 7c. We developed a means to use it as a feedback signal and succeeded in further reducing the required power.

Feedback control is also performed for controlling the electric motor 11 using the rotation speed detector 19.

Therefore, the present inventors used a wound induction motor as the drive motor 11, and controlled the rotation speed by adjusting the secondary resistance. The means should be selected.

Now, in the present invention, the rotation speed is set as follows.

The blower pressure is P1, the intake air volume (air volume) is Q, and the rotation speed is N.
Then, N=f(P,Q) ・・・・・・(1
).

In addition, the pressure loss in the pipes such as the intake branch pipes 8a to 8c and the intake main pipe 10 is Pp1, and the pressure loss when the purifier 13 is a dust collector is Pc, and the total pressure loss PL = PI) + PC is the air volume Q
and the damper opening degree, and is a function of these.

In other words, if the opening states of the control dampers 7a to 7c at the specific time t1 are collectively referred to as state S1, then PL=fS1(Q),
The state S2 at the specific time t2 becomes PL2f S2 (Q), and similarly, PL=fsi(Q) in the state Si.

Therefore, the required air volume in the intake branch pipes 8a to 8c (hereinafter there are many branch pipes and the final branch pipe is 8) in state Si is Q.
l (s i )・C2(Si), C3(si)...
...If Qk (si), the total air volume is Ql (si) +Q2 (s i) +Q3 (s
i)...+Qk(s i ) =ΣQk(s
i ) "" (2), where the required pressure of the blower P(si) is P(si) - fsi(ΣQk (s i ))
. . . (3) Therefore, the rotation speed N of the blower can be calculated as follows, and therefore the rotation speed of the drive motor 11 can also be set.

The control dampers 7a to 7c (or 7 in some cases)
The opening state (including up to k is the same as above) can also be obtained from the opening adjustment command signal of the control device 16, so
It should be understood that the above-mentioned state Si also has that meaning.

Next, in the above description, the control device 16 and the arithmetic device 17 were explained as separate devices, but they may be combined into the same unit to form a single arithmetic control device, or the arithmetic device 17 may be functionally divided. It can also be freely used as a rotation speed setting device, a rotation speed control circuit that compares the rotation speed setting value and the detected value and sends a command signal to make the deviation zero, and these are all within the free design scope of the present invention. It belongs.

Although the main damper 9 is not essential to the present invention, it may be used for equipment failure or other purposes.

Figure 4 shows one specific example of a converter ventilation dust collection system.

21 and 22 are two converters A and B, and each converter has three intake branch pipes, A1-A3, B1-B3.
is a control damper installed in each branch pipe.

5A and 5B show the working sequence of these two converters A and B, the opening/closing states of the control dampers A1 to B3 in each working state, and the air volume pattern in the main intake pipe 10.

As shown in FIG. 5, in the system shown in FIG. 4, the air volume fluctuates within a range of 75 to 100 degrees depending on each work state, and the duration of each air volume is as shown in the following table.

That is, the operating time at an air volume of 75 occupies a large proportion, and therefore it is of great significance to reduce the power consumption during low air volume operation.

FIG. 6 is a graph showing a normalized relationship between air volume Q and power consumption.

The straight line C1 is for damper control, and there is a proportional relationship between the air volume and the power consumption.

C2 to C4 are when speed control is performed, and 02 is when the blower is used.
The secondary resistance control of the drive induction motor, C3 is Cerbius control, and C4 is fluid joint control, these form a zo-squared curve.

Therefore, if speed control is performed, power consumption can be significantly reduced when the air volume is low.

The shaft power L1 of the blower is defined by the specific weight of the suction gas as r1, the pressure as P1, the air volume as Ql, and the efficiency of the blower as η, L1= r
PQ177 --- There is a relationship as shown in (5).

The change in η when the control damper is opened and closed depends on various factors, and it is difficult to express it mathematically, but from the actual result Ll
The relationship between y and Q is as shown by the straight line C1 in FIG. 6 (Ll is set as L in FIG. 6).

However, this relationship holds true when Q>4o%. Next, in the case of rotation speed control, the shaft power is proportional to the cube of the rotation speed N, and is 100
If the required power for the blower is L when the coefficient rotation speed (synchronous speed) is N100, and S is the 100% slip, the following relationship holds true.

Since the secondary efficiency η2 is 1-8, if the secondary input is La, then La=L/η2 =L/ (1-8)-Lloo (1
-8) When performing two-speed control using secondary resistance control, L
a-L is the secondary resistance loss.

The power consumption of the electric motor is determined by setting the first-order efficiency as η1, and N has a square relationship, resulting in a curve C2 in FIG. 6.

In the case of Servius, converted power is added to this, but it still has a square characteristic.

For example, controlling the rotation speed to control the air volume can be seen in household electric fans.

However, in large air supply and exhaust equipment equipped with a damper, the number of rotations of the blower is not controlled, and air volume control is entirely dependent on the opening degree control of the damper.

However, as detailed above, this is insufficient in terms of energy saving.

In this regard, if the rotational speed is controlled together with the damper control as in the present invention, the above-mentioned large power saving can be achieved, and the required amount of air can be taken into each location where the atmospheric gas to be purified is generated.

Furthermore, in the present invention, the rotation speed is controlled so that only the necessary amount of air is taken into the blower, so the blower rotation speed remains constant.5 Accidents such as damage due to an increase in negative pressure in the intake pipe that occurs when all dampers are closed can be avoided. does not occur, and has the advantage that there is no need to perform special control to avoid it.

As explained in detail above, the device of the present invention satisfies the purpose of purification and can significantly reduce the required power, and in the example used for dust collection in a converter factory, compared to known devices. We were able to achieve a power saving of 25 to 30 units in terms of power consumption.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the process order in converter equipment, Fig. 2 is a schematic explanatory diagram of a well-known purification device, Fig. 3 is a schematic explanatory diagram of an embodiment of the device according to the present invention, and Fig. 4 is FIG. 5 is an explanatory diagram showing a specific example of a converter ventilation dust collection system, FIG. 5 is an explanatory diagram showing air volume patterns etc. with respect to operating conditions, and FIG. 6 is a graph showing the relationship between air volume and power consumption. 6a-6c...Intake port, 7a-7c...
・Control damper, 8a to 8c...Intake branch pipe, 9
... Main pipe damper, 10 ... Intake main pipe, 11 ... Drive motor, 12 ... Blower, 13 ... Purification Devices, 14a to 14c...
...damper controller, 15a to 15c...
Opening degree detection device, 16... Control device, 17...
... Arithmetic device, 18 ... Motor control device, 1
9...Rotation speed detector.

Claims (1)

[Scope of Claims] 1. Intake branch pipes each having a crawler damper are arranged at locations where atmospheric gases that require purification are frequently generated, and a blower is provided to direct the suction gas to the purification device to the main intake pipe. The branch pipes are connected, and the electric motor that drives the blower is provided with a motor control device that controls its rotation speed, and each of the control dampers is configured to correspond to the process progress of the generation point to which the intake branch pipe belongs. A device is provided to control damper opening/closing according to a damper control pattern set in advance, and further, the opening signal of each control damper is inputted to determine the rotational speed of the electric motor required to suck the required total intake amount, and the 1. An atmospheric gas purification device comprising an arithmetic and control device that inputs a rotational speed command signal to a motor control device.