JPS60243234A - Method for controlling sintering of sintered ore - Google Patents

Abstract

PURPOSE:To control satisfactorily sintering by determining the grain size distribution of a raw material and the distribution of the rate of reduction of sintered ore by measuring the pressures in the raw material layer in the raw state and sintered ore layer in a pallet of a sintering machine. CONSTITUTION:Pipes 1a, b, c for measuring pressures are inserted through the attaching holes 4a of the side wall 4 of a pallet 2 to the upper layer part, middle layer part and lower layer part of the raw material layer 3 and the pressures Pa, b, c generated in the pipes are conducted to a pressure measuring device 7 through a transmission pipe 5. A calculator 7 processes the pressures and transmits the same to a control element for sintering. On the other hand, the opening degree of a damper in a wind box provided to the position where the pallet 2 passes is changed over to plural stages and the air quantity thereof is measured and is transmitted to the control element for sintering. The control element for sintering determines the grain size distribution in the layer direction and the distribution of the rate of reduction of the sintered ore in the unsintered state of the raw material and the thoroughly sintered state of the raw material from said air quantity and air pressures and controls the sintering in accordance with the determined distributions.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for controlling sintering of sintered ore, and in detail,
The pressure at the raw material charging section of the sintered ore raw material layer charged into the pallet of the sintering machine is measured to determine the particle size distribution of the raw material, and the pressure at the ore discharge section of the sintered ore layer is measured to determine the sintering. Considering the reduction rate distribution of condensation,
The present invention relates to a sintering control method for sintered ore, which controls the sintering of a sintered ore raw material based on these particle size distributions and reduction rate distributions.

[Prior art and its problems]

Traditionally, the sintering of raw materials has been controlled by measuring the particle size segregation and permeability of the sintered ore raw material layer charged into the pallet of the sintering machine, or the reduction rate of the sintered ore. .

Conventionally, grain size segregation in a raw material layer has been measured as follows. (1) Stop the sintering machine, stop the pallet from advancing and charging the raw materials, and allow a person to enter the raw material charging section and inside the pallet.
Sample the raw material charged into the container, measure its particle size, and calculate particle size segregation. (2) A sampler is placed on the pallet before the raw material is charged onto the pallet, and the sampler is loaded with the raw material when the raw material is loaded onto the pallet, and then the crane is placed between the raw material charging section and the ignition furnace. The sampler is pulled up from the pallet and collected, and the particle size of the raw material inside the sampler is measured to determine particle size segregation in the layer direction of the raw material layer.

However, method (1) (a) stops the sintering machine, which disrupts operations and reduces production efficiency, (b) requires labor for sampling, and (C) requires drying of the sampled raw material. Since the particle size is measured by separating the particles with a sieve, it takes time and effort to measure the particle size, and the disadvantage is that the particle size can only be measured once a day. In addition, method (2) is (a)
This method has drawbacks such as the number of sampling points in the raw material layer is small, and (b) measurement of particle size is the same as method (1), so measurement can only be performed once a day.

In addition, the permeability of the raw material layer is determined from the relationship between pressure and air volume by measuring the pressure (negative pressure) and air volume of the wind box in front of the ignition furnace where the raw materials in the pallet are in the raw raw material state. However, the air permeability determined in this way is the air permeability of the entire raw material layer within the pallet, and does not reflect the details of the properties within the raw material layer so as not to indicate particle size segregation in the raw material layer1. do not have.

The reduction rate of sintered ore is measured by sampling the finished sintered ore on the conveyor at the exit of the sintering factory.However,
Such sintered ore is used as a raw material in the upper, middle and upper layers of the raw material layer.
Since the sintered ore located in each layer, such as the sintered ore and the lower layer, are combined together, it is unclear which layer the sintered ore corresponds to in the measurement of the reduction rate.

Therefore, in the conventional sintering control method, the particle size distribution of the raw material layer, the reduction rate of the sintered ore, etc. are not considered in detail, which makes it difficult to perform good sintering control.

[Purpose of the invention]

In view of the above-mentioned current situation, this invention aims to improve the particle size distribution of the raw material in the pallet without sampling the raw material at the raw material charging section or sampling the finished sintered ore outside the sintering plant. An object of the present invention is to provide a method for controlling sintering of sintered ore, which enables good sintering control by determining the reduction rate distribution in detail.

[Summary of the invention]

This invention involves inserting pressure measuring pipes at intervals in the layer direction into layers of sintered ore raw material charged in a pallet of a sintering machine, and when the raw material is in an unsintered state. At the same time, the damper opening degree of the wind box at the position where the pallet passes is changed to multiple levels to measure the air volume of the wind box, and at the same time, the pressure measurement pipe is used to measure the raw material at the location where the pressure measurement pipe is inserted. The air pressure in the layer is measured, and the particle size distribution in the layer direction in the unsintered state of the raw material is determined from the air volume and air pressure, and then the raw material is sintered and becomes sintered ore. At the same time, the damper opening degree of the wind box at the position where the pallet passes is changed to multiple stages to measure the air volume of the wind box, and at the same time, the pressure measuring pipe is inserted by the pressure measuring pipe. Measure the air pressure in the layer of the sintered ore at the location, calculate the reduction rate distribution in the layer direction of the sintered ore from the air volume and air pressure, and calculate the particle size distribution of the raw material and the sintered ore determined in this way. The method is characterized in that the sintering of the raw material is controlled based on the reduction rate distribution.

[Structure of the invention]

FIG. 1 is a detailed explanatory diagram of the present invention. In Fig. 1, la, lb and IC are pressure measuring pipes for measuring the air pressure in the layer 3 of sintered ore raw material charged into the pallet 2 of the sintering machine, and the pipes la, lb and IC are The sidewalls 4 of the pallet 2 are inserted through the holes 4a into the lower part of the upper layer, the lower part of the middle layer, and the lower part of the lower layer of the raw material layer 3, respectively, by means of a pipe insertion device (not shown). The pressure measuring pipes 1a to 1C are made of heat-resistant material such as stainless steel and have a small hole provided on the side surface of the tip thereof, and the pressures Pa, Pb, and Pc generated in the pipes 1a to 1c through the small holes are the ~Transmission pipe 5 made of a hard resin pipe attached to the rear end of 1c
The pressure is guided to a pressure measuring device 6 attached to the bottom of the pallet 2 and measured there. This measured pressure P
a, Pb, and Pc are transmitted from the pressure measuring device 6 to a calculator 7 installed outside the sintering machine using an FM method or the like, and are subjected to necessary processing there. The calculator 7 then generates control signals for the sintering control elements.

The pressure is measured by the pressure measurement pipes 1a to IC when the raw material layer 3 in the pallet 2 is unsintered and still in a raw state, and when the raw material layer 3 has been sintered and has become sintered ore. Do it when the situation is That is, as shown in FIG.
a~ When the pallet 2a in which the IC is inserted is moving between the raw material charging section 9 consisting of the surge hopper 8 etc. and the ignition furnace 10, and when the pallet 2a has reached the vicinity of the ore discharge section 11. Measurements are taken while moving and proceeding in front of the ore discharge section 11.

In this case, as shown in FIG. 3, the opening degree of the damper 13 of the wind box 12a of the wind box 12a of the sintering machine at the part through which the pallet 2a passes is changed in three or more steps to change the air volume. -Measure the pressure in the pipes 1a to 1c each time the pipes are replaced. Also, the air volume at that time was determined by the wind box 12. Measurement is performed using a hot wire anemometer 14 installed inside a. The above-mentioned measurements also apply to measurements before the ore discharge section 11.

As shown in FIG. 3, the pressure at the bottom of the soil layer of the raw material layer 3 in the pallet 2a is determined by the pressure measurement as shown in FIG. Paz, Pa3- (Pai), pressure at the bottom of the middle layer Pb+, Pb2゜Pb3- (Pbi) and pressure at the bottom of the bottom layer Pc+, Pc2゜Pc3... (P
c i ) is established, and from this the differential pressure between the upper and lower layers in the upper, middle and lower layers △Pai =Pai, △Pbi =p
bi −Pai , △Pc1=Pci−Pbi (i=
1, 2, 3-) are observed.

Here, the pressure loss ΔP in each of the upper layer, middle layer, and lower layer of the raw material layer 3 in the raw state can be expressed as follows using Ergun's formula.

)...■ However, △P: pressure loss of each layer of raw material layer, L: Height of each layer of raw material layer, U: Air wind speed, ρ: density of air, μ: Viscosity coefficient of air, ε　：Porosity of each layer of raw material layer, φ: Shape factor of raw material particles, dp: Particle diameter of raw material particles.

In the above equation, the height L of each raw material layer is known, and the air wind speed U can be calculated from the air volume V and the rent floor area S.
= V/S, so for example, the differential pressure △ at the upper layer of the raw material layer
Pa1. △Paz, △Pa3. ...and the air volume at that time V, , V2. From V3..., the ■ formula is solved,
■The unknown coefficients a and b of the equation are rounded. unknown coefficient a.

Once b is determined, the density ρ of air and the viscosity coefficient μ of air in the above equation 0 are known, so from equation 0, the product φdp of the shape coefficient φ and the particle diameter dp and the porosity ε in the upper layer of the raw material layer are calculated.

Similarly, the differential pressure in the middle layer of the raw material layer △Pb+, ΔPbz
.

ΔPb3... and the air volume V, , V2. V3...
・From this, φdp and ε in the middle layer of the raw material layer are the differential pressure Δpet in the lower layer of the raw material layer.

△PC2, △PC,! ...and the air volume V, , V2
．． From V3..., φap and ε at the middle layer of the raw material layer are rounded.

In addition, in the same manner as above, from the measurement of the pressure and air volume in front of the ore discharge section 11, the product of the shape factor and particle diameter φdp in the upper, middle, and lower layers of sintered ore in the pant) 2a
and the porosity ε is equal.

As described above, the coefficients a, b and φ of the ErgunO equation are
Table 1 shows examples of the results for the raw material layer (unsintered) and the sintered ore layer (unsintered) in which dp and ε were determined.

Of the product φdp of the shape factor φ and the particle diameter dp and the porosity ε, φdp is important for the raw material layer in a raw state, and ε is important for the sintered ore layer. That is, from φdp, it is possible to estimate the particle size segregation in the layer direction of the raw material charged into the pallet (the uneven distribution of coarse grains and fine grains of the raw material in the layer direction). According to Table 1, φ of the raw material layer (unsintered)
The dp is small in the upper layer and large in the lower layer, and the raw material exhibits a segregated state.

Table 1 The porosity ε of the sintered ore layer has a certain relationship with the reduction rate of the sintered ore, as shown in FIG. 4, and the reduction rate of the sintered ore can be estimated from ε. The higher the porosity ε, the higher the reduction rate of the sintered ore.

From the above, for the raw material layer in the raw state, φdp is determined, the grain size distribution in the layer direction is determined, and this grain size distribution is controlled so that it becomes the optimal grain size distribution obtained from the operational analysis of sinter production. Do the following. For the sintered ore layer, determine the porosity ε and the reduction rate, determine the reduction rate distribution in the layer direction, and control so that this reduction rate distribution becomes the optimal reduction rate distribution similarly obtained from the operation analysis. . Factors that control particle size distribution include the angle of the charging chute and the rotation speed of the roll feeder. Elements that control the reduction rate include carbon segregation in the raw material layer, coke particle size, and ignition strength in the ignition furnace. Therefore, these control elements are adjusted to perform sintering control that controls the particle size distribution of the raw material and the reduction rate distribution of the sintered ore.

〔Effect of the invention〕

This invention measures the pressure between the raw raw material layer and the sintered ore layer in the sintering machine pallet, and determines the particle size distribution of the raw material and the reduction rate distribution of the sintered ore from the air volume of the wind box at that time. This not only eliminates the need for sampling the raw material at the raw material charging section and sampling the finished sintered ore outside the sintering plant, but also improves particle size distribution and reduction rate distribution. Since it can be observed in detail, good sintering control can be performed.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram for explaining the invention in detail;
The figure is a diagram showing the measurement positions on the sintering machine for pressure measurement of the raw material layer and sintered ore layer performed in the method of the present invention, and FIG. 3 is an explanatory diagram showing the pressure measurement of the raw material layer performed in the method of the present invention. - Figure 4 is a graph showing the relationship between the porosity of the sintered ore layer and the reduction rate of the sintered ore. In the drawings, 1a to 1c...Pipe for pressure measurement, 2.2a...Pallet, 3...Raw material layer, 4...Side wall, 4a...Mounting hole, 5...Transmission pipe ,
6...Pressure measuring device, 7...Calculation B, 8...
Thurso hopper, 9... Raw material charging section, 10... Ignition furnace, 11... Ore discharge section, 12, 12a... Wind box,
13... Damper, 14... Hot wire anemometer. Applicant: Nippon Kokan Co., Ltd., Agent: Natsuo Shioya (and 2 others)

Claims (1)

[Claims] Pressure measuring pipes are inserted at intervals in the layer direction into the layers of sintered ore raw material charged into a pallet of a sintering machine, and when the raw materials are in an unsintered state, At the same time, the air volume of the wind box is measured by changing the damper opening degree of the wind box at the position where the pressure measurement pipe passes through multiple stages, and at the same time, the layer of the raw material at the location where the pressure measurement pipe is inserted is measured by the pressure measurement pipe. Measure the air pressure inside, calculate the particle size distribution in the layer direction when the raw material is in an unsintered state from this air volume and air pressure, and then calculate the state in which the raw material has completed sintering and has become sintered ore. At the same time, the damper opening degree of the wind box at the position where the pallet passes is changed to multiple stages to measure the air volume of the wind box, and at the same time, the pressure measurement pipe is inserted into the location where the pressure measurement pipe is inserted. The air pressure in the layer of the sintered ore is measured, and the reduction rate distribution in the layer direction of the sintered ore is calculated from the air volume and air pressure, and the particle size distribution of the raw material determined in this way and the sintered ore are calculated. 1. A sintering control method for sintered ore, characterized in that sintering of the raw material is controlled based on a reduction rate distribution.