JP2679558B2 - Operating method of electric dust collector for main exhaust gas of sintering machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of operating an electrostatic precipitator used for collecting the main exhaust gas of a sintering machine, and more particularly, to reduce the concentration of dust particles in the exhaust gas from the electrostatic precipitator outlet within a set range. Driving method for doing.

[0002]

2. Description of the Related Art Cyclones have been widely used in dust collectors of sintering machines, but most of them use dry electrostatic precipitators due to stricter pollution regulations.

The dust collection efficiency η of the electrostatic precipitator is represented by η = 1-e- ^{wA / Q} from the Deutsche equation. However, w is the dust moving speed, A is the capacity of the electrostatic precipitator, and Q is the amount of exhaust gas. Here, since the capacity A of the electrostatic precipitator is fixed, the items that change the dust collection efficiency η during operation are the dust moving speed w and the exhaust gas amount Q. The dust moving speed is the speed at which anions formed by corona discharge are charged to dust and are attracted to the dust collector plate, which is the positive electrode, by the Coulomb force.

Conventionally, in order to maintain the dust collection efficiency of the electric dust collector, a method has been taken in which only the electric dust collector is used. That is, (1) a hammering device is used to intermittently hammer the dust collecting electrode to mechanically remove the accumulated dust on the surface of the dust collecting electrode to increase the dust moving speed W, and (2) a dust collecting plate. The dust collection efficiency η greatly changes depending on the value of the electrical resistance value ρd of the dust layer deposited and deposited, and is represented by ρd = f (moisture, temperature). Therefore, the electrical resistance value is measured by actually measuring the water content and temperature in the gas. ρd is calculated, and among the four areas shown below, B,
A method of controlling by determining whether it is in the area C or D has been adopted.

Area A (rescattering, η = 0) Area B (normal, good η) 1 × 10 ⁴ ≦ ρd ≦ 5 × 10
¹⁰ (Ω · cm) C region (frequent sparks, η deterioration) 5 × 10 ⁵ ≦ ρd ≦ 1 × 1
0 ¹¹ (Ω · cm) D region (reverse ionization, η deterioration) 1 × 10 ¹² ≦ ρd (Ω · c
m)

Further, (3) a method has been proposed in which the most suitable charge control of an electrostatic precipitator is selectively applied to each of the above four areas to enhance the dust collecting efficiency (Japanese Patent Laid-Open No. 60-94160).
Reference). This method focuses on the fact that the apparent resistivity value of dust is greatly affected by temperature and humidity, and by measuring this as a parameter, the apparent resistivity value of dust is calculated to obtain the dust collection electrode. In this method, the charging method is selected by automatically determining the occurrence and state of back corona that generates cations and diffuses into the dust collecting space.

(4) The outlet of the electrostatic precipitator, which detects the concentration of dust particles in the exhaust gas from the outlet of the electrostatic precipitator and adjusts the charging rate of the electrostatic precipitator that performs intermittent charging when the detected value is out of the set range. A method has been proposed in which the dust concentration in exhaust gas is controlled to fall within a set range (Japanese Patent Laid-Open No. 59-365).
No. 59).

[0008]

However, the above-mentioned conventional methods have the following drawbacks. That is, (1)
The method of mechanically removing dust accumulated on the surface of the dust collecting electrode by intermittently hammering the dust collecting electrode with the hammering device and increasing the dust moving speed W ignores the conditions on the inlet side of the electrostatic precipitator. Since the electrostatic precipitator is used alone, the dust collection efficiency η is controlled by fluctuations on the inlet side of the electrostatic precipitator, which is not stable.
In (2) and (3), the electric resistance value ρd is calculated by actually measuring the water content and temperature in the gas, and the electrostatic precipitator charging control is performed. It is limited to only and does not consider other variables,
Since the electrostatic precipitator charging control is controlled to be constant in the area, it is not possible to deal with minute fluctuations within the area, and the dust concentration in the exhaust gas from the electric precipitator outlet, which is the final output, is not directly controlled, so the dust collection efficiency There are drawbacks such as not being able to accurately grasp η, and because the sintering operation conditions that make up the input conditions of the electrostatic precipitator are not directly controlled, the input conditions of the electrostatic precipitator are not necessarily optimum for the dust collection efficiency η.

Further, even in the method (4) of controlling the charge rate according to the concentration of the dust particles at the outlet of the electrostatic precipitator, the conditions on the inlet side of the electrostatic precipitator, which is a variable factor of the dust collecting efficiency η, are not considered at all. There is a drawback that the optimum control for increasing the dust collection efficiency η cannot be sufficiently performed.

The present invention has been made in order to solve the above-mentioned drawbacks of the prior art, and is mainly intended for a sintering machine which can reduce the concentration of dust particles in the exhaust gas of the electrostatic precipitator in response to fluctuations in the inlet side conditions of the electrostatic precipitator. It is intended to propose a method of operating an electric dust collector for exhaust gas.

[0011]

The present invention always maximizes the dust collection efficiency η of the electric precipitator by directly controlling the sintering operation and the electric precipitator, which are responsible for the factor relating to the dust collection efficiency η of the electric precipitator. That is, it is a method that enables the optimal operation that can minimize the dust concentration in the exhaust gas of the electrostatic precipitator outlet, the gist is the sintering machine exhaust gas properties that are the input conditions of the electrostatic precipitator, the charging status of the electrostatic precipitator,
The dust concentration in the exhaust gas from the dust collector outlet, which is the output condition of the dust collector, and the operating conditions of the sintering machine and the operating conditions of the electric dust collector are incorporated into the arithmetic device, and the arithmetic device is used to minimize the dust concentration in the exhaust gas from the electric dust collector outlet. A method for operating an electrostatic precipitator for a main exhaust gas of a sintering machine, characterized in that the operating conditions of the sintering machine and the operating conditions of the electrostatic precipitator are obtained and the sintering machine and the electrostatic precipitator are continuously controlled.

[0012]

According to the present invention, the factors related to the dust moving speed w (η = 1-e- ^{wA / Q} ) related to the dust collection efficiency η in the exhaust gas properties of the sintering machine which are the input conditions of the electric dust collector, and the electric The calculation device (computer) calculates all the factors related to the dust moving speed w in the dust collector charging status, and the calculation device calculates the dust concentration in the exhaust gas from the dust collector outlet, which is the output condition of the electric dust collector. The treatment is performed, and the result is fed back to the sintering operation condition and the operation condition of the electrostatic precipitator that directly produce the exhaust gas property and the charging condition of the electrostatic precipitator to control the sintering machine and the electrostatic precipitator.

The dust moving speed w related to the dust collecting efficiency η in the exhaust gas properties of the sintering machine and the charging condition of the electric dust collector.
Factors related to are as follows. Exhaust gas property W = f (inlet side the dust concentration, the amount of exhaust gas, SOx, _{0 2,} water concentration, oil, alkali content, temperature) electrostatic precipitators charge status W = g (peak voltage Vp, the average voltage Vave, bottom voltage Vb)

[0014]

1 is a block diagram showing an embodiment of an operating method of an electrostatic precipitator according to the present invention, in which 1 is a sintering machine, 2 is an electrostatic precipitator, 3 is a chimney, and 4 is a computer (computer). .

The main exhaust gas of the sintering machine 1 is introduced into the electrostatic precipitator 2 to collect dust, and is discharged from the chimney 3 into the atmosphere. In the present invention, the exhaust gas properties of the sintering machine 1, the charging status of the electric dust collector 2, the dust concentration in the exhaust gas from the electric dust collector outlet, the operating conditions of the sintering machine and the operating conditions of the electric dust collector are input to the computing device 4, where the exhaust gas from the dust collector outlet is input. Sintering machine operating conditions and electrostatic precipitator operating conditions are determined so that the concentration of dust particles in the inside is minimized, and the results are fed back to the sintering machine operating conditions and electrostatic precipitator operating conditions, respectively. Here, data on the electrostatic precipitator, gas properties on the inlet side of the electrostatic precipitator, and sintering operation conditions are shown in Table 1, Table 2, and Table 3, respectively. E in Table 1
P1F to EP4F mean that there are four dust collecting chambers of the electrostatic precipitator.

That is, in FIG. 1, the exhaust gas property data which is the input condition of the electrostatic precipitator 2 and the dust concentration in the exhaust gas at the outlet of the electrostatic precipitator are input to the arithmetic unit 4 through an AD converter or the like. In addition, since the voltage value of the charge condition of the electrostatic precipitator changes in the order of μsec, the waveform is read by the digital storage scope and input to the arithmetic unit 4 through various converters. Furthermore, the operating conditions of the sintering machine and the operating conditions of the electrostatic precipitator are also input to the arithmetic unit 4. The arithmetic unit 4 calculates the sintering operation conditions and the electrostatic precipitator operating conditions for minimizing the concentration of dust particles in the exhaust gas at the outlet of the electrostatic precipitator by performing arithmetic processing based on the above input data, and calculates the operating conditions of the sintering machine. Feed back to the operating conditions of the electrostatic precipitator for control. As a result, the dust concentration in the exhaust gas at the outlet of the electrostatic precipitator can be stabilized at a low level.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

[Table 3]

[0020]

As described above, according to the method of the present invention, the factor of fluctuation in the performance of the electrostatic precipitator is taken into the computer in consideration of the input condition of the electrostatic precipitator, which is hardly considered in the past, that is, the exhaust gas property of the sintering machine. The sintering operation condition and the electrostatic precipitator operating condition for minimizing the dust concentration in the exhaust gas from the electric precipitator outlet are calculated and obtained, and the sintering machine and the electric precipitator can be controlled based on this result. The dust collection efficiency of the electrostatic precipitator can always be kept to the maximum, and the great effect that the concentration of dust particles in the exhaust gas at the outlet of the electrostatic precipitator can be significantly reduced is achieved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a method of operating an electrostatic precipitator according to the present invention.

[Explanation of symbols]

 1 Sintering machine 2 Electrostatic precipitator 3 Chimney 4 Computing device

Claims (1)

(57) [Claims] Claims: 1. The exhaust gas properties of the sintering machine, which are the input conditions of the electrostatic precipitator, the charging status of the electrostatic precipitator, the dust concentration in the exhaust gas at the dust collector outlet, which is the output condition of the electrostatic precipitator, the operating conditions of the sintering machine and the operating conditions of the electrostatic precipitator. Incorporate it into a computer to obtain the operating conditions of the sinter and the operating conditions of the electrostatic precipitator by the aforementioned computer so that the concentration of dust particles in the exhaust gas from the outlet of the electrostatic precipitator is minimized, and control the sintering machine and the electrostatic precipitator continuously A method of operating an electrostatic precipitator for a main exhaust gas of a sintering machine.