JPS6383210A - Pre-reduction smelting apparatus - Google Patents

Abstract

PURPOSE:To stabilize the operation by operating reduction ratio at outlet of a pre- reduction furnace from gas temps. and compositions flowing a high temp. gas supplying tube and an exhaust gas tube, and composition and quantity of supplying raw material to adjust supplying raw material quantity and control the reduction ratio to the prescribed value. CONSTITUTION:The reducing reaction condition measuring means 12, 13 are fitted to the high temp. gas supplying tube 4 and the exhaust gas tube 8 respectively, to meausre the composition and temp. of flowing gas in the pipes, 4, 8. And the raw material condition measuring means 11 is fitted to the raw material supplying tube 4, to measure the composition and temp. of raw material. Further, the flow rate measuring means 14 is fitted to a piping between a heat recovery device 7 and a decarbonic acid device 9, to measure exhaust gas flow rate. The output signal of each measuring means 11-14 is transmitted to an arithmetic unit 17, to calculate the reduction ratio at a part of extracting tube 5 at the outlet part of pre-reduction furnace 1. In accordance with this reduction ratio, the composition and supplying quantity of raw material supplied in the pre-reduction furnace 1 are set up. In this way, as the reduction ratio in the pre-reduction furnace 1 is operated under controlling to the constant value, the stable operation for a smelting reduction furnace 3 is obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is capable of controlling the reduction rate to a predetermined value by measuring the components, temperature, flow rate, and pressure of high-temperature gas supplied to a preliminary reduction furnace. This invention relates to a preliminary reduction smelting device.

[Prior Art] A converter type device is known as a smelting reduction smelting device. This device forms a fluidized bed using exhaust gas generated from a melt reduction furnace that performs melt reduction. Therefore, productivity is improved by pre-reducing the iron ore with the exhaust gas cooled to 1000 to 1200° C. and then charging it into the smelting reduction furnace. As such a pre-reduction smelting apparatus, a so-called fluidized bed type pre-reduction smelting apparatus, which can use both coarse and fine raw materials, is generally employed.

[Problems to be solved or attempted by the invention] However, in the case where the preliminary reduction is performed using the exhaust gas generated from the smelting reduction furnace, the preliminary reduction rate may vary due to variations in the composition and temperature of the inlet gas, variations in the raw material composition, etc. It is extremely difficult to drive with a constant value. As a result, it has been difficult to operate the melting reduction furnace stably.

The present invention has been made in view of this point, and by controlling and operating the reduction rate of the pre-reduction furnace at a constant level,
The present invention provides a preliminary reduction smelting device that can stably operate a smelting reduction furnace.

[Means for Solving the Problems] The present invention provides a preliminary reduction furnace in which a predetermined raw material is fed into the hearth from a raw material supply pipe, and a high-temperature gas supply system in which high-temperature gas is supplied from a melting reduction furnace to the preliminary reduction furnace. A pre-reduction product comprising a supply pipe, an exhaust gas discharge pipe that guides the exhaust gas generated in the pre-reduction furnace to the heat recovery device, and a gas supply pipe that supplies the exhaust gas exiting the heat recovery device as a predetermined gas source. In the refining equipment, a means for measuring reduction reaction conditions is installed to measure the components, temperature, flow rate, and pressure of the gas flowing in the high-temperature gas supply pipe and the exhaust gas discharge pipe, respectively. a raw material condition measuring means for measuring the ingredients and supply amount of the raw material, and a calculating section for calculating the reduction rate at the outlet of the preliminary reduction furnace based on the measurement signals from the reduction reaction condition measuring means and the raw material condition measuring means. This is a preliminary reduction smelting device that increases or decreases the amount of feedstock based on the output signal of the calculation section and controls the reduction rate to a predetermined value.

Further, the preliminary reduction smelting device includes a return gas supply pipe that recycles the exhaust gas exiting the heat recovery device and supplies it to the preliminary reduction furnace; An exhaust gas property adjusting means for adjusting the components, temperature, and flow rate of the exhaust gas supplied to the furnace may also be provided.

[Operation] According to the pre-reduction smelting apparatus according to the present invention, first, the components, temperature, flow rate, and pressure of the high-temperature gas supplied to the pre-reduction furnace and the exhaust gas from the pre-reduction furnace are measured.

Next, the components and supply amount of the raw material to be supplied to the preliminary reduction furnace are measured. Next, the measured values obtained in this manner are supplied to a calculation section to calculate the reduction rate at the outlet of the preliminary reduction furnace. Thereafter, the amount of feedstock is increased or decreased based on this calculated value to control the reduction rate of the preliminary reduction furnace to a predetermined value. By controlling and operating the reduction rate of the preliminary reduction furnace at a constant value in this manner, the melting reduction furnace can be stably operated.

In addition, when a return gas supply pipe and exhaust gas property adjustment means are added, firstly, the components, temperature, flow rate, and pressure of the high-temperature gas supplied to the pre-reduction furnace, the recycled exhaust gas, and the exhaust gas from the pre-reduction furnace are determined. Measure. Next, the components and supply amount of the raw material to be supplied to the preliminary reduction furnace are measured. Next, the measured values obtained in this manner are supplied to a calculation section to calculate the reduction rate at the outlet of the preliminary reduction furnace. If the calculated reduction rate does not reach the target value, the composition, temperature, and flow rate of the exhaust gas supplied from the return gas supply pipe to the pre-reduction furnace are adjusted by the exhaust gas property control means based on this calculated value. Control the return rate to a predetermined value. By controlling and operating the reduction rate of the preliminary reduction furnace at a constant value in this manner, the melting reduction furnace can be stably operated.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram showing a schematic configuration of a preliminary reduction smelting apparatus according to an embodiment of the present invention. 1 in the figure is a preliminary reduction furnace. A raw material supply pipe 2 is provided on the lower side of the pre-reduction furnace 1 to feed iron ore as a raw material into the hearth. At the bottom of the preliminary reduction furnace 1, 1000 to 120
A high temperature gas supply pipe 4 is provided for flowing the molten reducing gas cooled to 0° C. into the furnace. Further, on the side of the preliminary reduction furnace 1, the preliminary reduced iron ore is placed in the smelting reduction furnace 3.
An extraction pipe 5 is formed for guiding the air to the air.

An exhaust gas discharge pipe 8 is connected to the top of the furnace for guiding the exhaust gas after the reaction which has undergone preliminary reduction to a heat recovery device 7 via a dust collector 6. The exhaust gas leaving the heat recovery device 7 is sent to the decarbonation device 9.
, and the blower 10 in order, and are supplied to a heat source section (not shown).

A raw material condition measuring means 11 is attached to the raw material supply pipe 2 to measure the components and supply amount of the raw material supplied into the furnace. The raw material component means 11a is, for example, a sampling device.
Composed of a titration analyzer, the component means 11b for determining the raw material supply amount
For example, it consists of a constant feed sea urchin ear. Further, a first reduction reaction condition measuring means 12 is attached to the high temperature gas supply pipe 4 to measure the components and temperature of the high temperature gas supplied into the furnace. High temperature gas component means 1
2a is composed of, for example, gas chromatography, and the high-temperature gas temperature measuring means 12b is composed of, for example, a platinum-platinum-rhodium thermocouple. Further, a second reduction reaction condition measuring means 13 is attached to the gas supply pipe 8 to measure the components and temperature of the hot exhaust gas from the furnace. The exhaust gas component means 13a is composed of, for example, gas chromatography, and the exhaust gas temperature measuring means 13b is composed of, for example, a chromel-alumel thermal lightning pair. Furthermore, a flow rate means 14 is attached to the pipe leading from the heat recovery device 7 to the decarbonation device 9 to measure the flow rate of the exhaust gas after heat recovery.

The flow rate means 14, the second reduction reaction condition measurement means 13, the first reduction reaction condition measurement means 12, and the raw material condition measurement means 11,
A predetermined output signal is supplied to the calculation section 17. The calculation unit 17 performs calculation processing based on the signals supplied from these measurement means, and calculates the reduction rate at the extraction pipe 5, which is the outlet of the preliminary reduction furnace 1. . The calculation unit 17 outputs a signal according to the calculated reduction rate, and sets the components and supply amount of the raw material to be supplied from the raw material supply pipe 2 into the furnace to predetermined values.

According to the preliminary reduction smelting apparatus configured as described above, iron ore as a raw material is first charged into the hearth portion from the raw material supply pipe 2. Next, the molten reducing gas cooled to 1000 to 1200° C. is supplied from the smelting reduction furnace 3 to the preliminary reduction furnace 1 via the high temperature gas supply pipe 4 to perform preliminary reduction. The exhaust gas generated by preliminary reduction in the furnace is passed from the top of the furnace through an exhaust gas discharge pipe 8 to a dust collector 6, a heat recovery device 7, a decarboxylation device 9,
The gas is sequentially supplied to the blower 10 and effectively used as a predetermined gas source. On the other hand, the iron ore that has been subjected to a predetermined preliminary reduction is supplied from the extraction pipe 5 to the smelting reduction furnace 3. At this time, the reduction rate of the iron ore discharged from the extraction pipe 5 is determined by the raw material condition measuring means 11, the first reduction reaction condition measuring means 12, and the second reduction reaction condition measuring means 12.
The calculation section 17 receives predetermined output signals from the reduction reaction condition measuring means 13 and performs calculation processing based on these signals. The reduction rate can be determined, for example, by the following formula.

Preliminary reduction rate - (ΔPe2 o 3 ) / (Pe2
o 3 ) x 100% (ΔPe203): Measured value in 11a above - Calculated value at outlet of preliminary reduction furnace (Pe O): Measured value in 11a above.If the calculated reduction rate is not within the predetermined value, calculate The unit 17 outputs a signal corresponding to the calculated reduction rate, and sets the components or supply amount of the raw material to be supplied from the raw material supply pipe 2 into the furnace to a predetermined value. In this case, the calculation unit 17 calculates the return rate in consideration of the output signal of the flow rate measuring means 14 as necessary. In this way, the reduction rate of the preliminary reduction furnace 1 is controlled to a predetermined value. As a result, the reduction rate of the preliminary reduction furnace 1 can be controlled to a constant value at all times, so that stable operation of the smelting reduction furnace 3 can be realized.

Incidentally, when the target reduction rate was set to 10% using the preliminary reduction smelting apparatus of the example and preliminary reduction was performed under the following operating conditions, the reduction rate calculated by the calculation unit 17 was 9%. Ta. Therefore, when a predetermined signal was output from the calculation unit 17 and the feed rate of the raw material was changed as shown below, a reduction rate (10.1%) approximately equal to the target value was obtained.

Operating conditions Raw material components Ore (T-F B7.0%, Fe05
%) Raw material supply amount 1874/(g/H, raw material supply amount after change IB87Kg/H.

Composition of hot gas H2 (4,92%), H2O (21,42%).

CO (42,08%), Co2 (31,3ft%)
.

N2 (0.22%) Flow rate 1437N m3 Temperature 1800℃ Components of exhaust gas H2 (7,89%), H2O (1B, 83%).

C0 (38,11%), CO2 (37,15%).

N 2 (0.22%) Flow rate: 2388 Nm'' Temperature: 1150° C. Next, other embodiments of the present invention will be described with reference to the drawings.

FIG. 2 is an explanatory diagram showing a schematic configuration of a preliminary reduction smelting apparatus according to another embodiment of the present invention. The same parts as in the previous embodiment are given the same reference numerals. At the lower part of the preliminary reduction furnace 1, there is a raw material supply pipe 2 for feeding iron ore as a raw material into the hearth part.
is provided.

At the bottom of the preliminary reduction furnace 1, 1000~
A high-temperature gas supply pipe 4 is provided for flowing molten reducing gas cooled to 1200° C. into the furnace. Furthermore, exhaust gas, which will be described later, is supplied to the bottom of the preliminary reduction furnace 1 as a recycled gas from a return gas supply pipe 21. An extraction pipe 5 is formed on the side of the preliminary reduction furnace 1 for guiding the preliminary reduced iron ore to the smelting reduction furnace 3. An exhaust gas discharge pipe 8 is connected to the top of the furnace for guiding the exhaust gas after the reaction which has undergone preliminary reduction to a heat recovery device 7 via a dust collector 6. The exhaust gas exiting the heat recovery device 7 passes through a decarboxylation device 9 and a first blower 10 in sequence, and is supplied to a lower process (not shown). A part of the exhaust gas exiting the first blower 10 is supplied as recycle gas to the preliminary reduction furnace 1 through a return gas supply pipe 21 through a second blower 22 and an exhaust gas property adjusting means 23 in sequence. A raw material condition measuring means 11 is attached to the raw material supply pipe 2 to measure the components and supply amount of the raw material supplied into the furnace. The raw material component measuring means 11a is composed of, for example, a sampling device-titration analyzer, and the raw material supply amount component measuring means 11b is composed of, for example, a constant feed unit. In addition, the high temperature gas supply pipe 4 includes
A first reduction reaction condition measuring means 12 is installed to measure the components, temperature, and flow rate of the high-temperature gas supplied into the furnace.

The high-temperature gas component measuring means 12a is composed of, for example, gas chromatography, and the high-temperature gas temperature measuring means 12b
is composed of, for example, a platinum-platinum-rhodium thermal lightning pair, and the high-temperature gas flow rate measuring means 12c is composed of, for example, an orifice.

Further, a second reduction reaction condition measuring means 13 is attached to the gas supply pipe 8 to measure the components, temperature, and flow rate of the exhaust gas from the furnace. The exhaust gas component measuring means 13a is composed of, for example, gas chromatography, the exhaust gas temperature measuring means 13b is composed of, for example, a chromel-alumel thermocouple, and the exhaust gas flow rate measuring means 13c is composed of, for example, an orifice. A third reduction reaction condition measuring means 24 is installed between the second blower 22 and the exhaust gas property adjusting means 23. The recycled exhaust gas component measuring means 24a is composed of, for example, gas chromatography, the exhaust gas temperature measuring means 24b is composed of, for example, a mercury thermometer, and the exhaust gas flow rate measuring means 24c is composed of, for example, an orifice. . The exhaust gas property adjusting means 23 is composed of a flow meter 23a and a flow rate regulating valve 23b. Further, a flow rate measuring means 14 for measuring the flow rate of the exhaust gas after heat recovery is attached to the pipe leading from the heat recovery device 7 to the decarbonation device 9. Flow rate measurement means 14, third reduction reaction condition measurement means 24, second reduction reaction condition measurement means 13
, the first reduction reaction condition measuring means 12 and the raw material condition measuring means 11 are adapted to supply predetermined output signals to the calculation unit 17.

The calculation unit 17 performs calculation processing based on the signals supplied from these measurement means, and calculates the reduction rate at the extraction pipe 5, which is the outlet of the preliminary reduction furnace 1. . The calculation unit 17 outputs a signal according to the calculated reduction rate, and if the calculated reduction rate does not reach the target value, the exhaust gas property adjustment means controls the return gas from the return gas supply pipe to the preliminary reduction furnace based on this calculated value. Components of exhaust gas to be supplied,
The temperature and flow rate are adjusted to control the reduction rate of the preliminary reduction furnace to a predetermined value.

According to the preliminary reduction smelting apparatus configured as described above, iron ore as a raw material is first charged into the hearth portion from the raw material supply pipe 2. Next, the molten reducing gas cooled to 1000 to 1200° C. is supplied from the smelting reduction furnace 3 to the preliminary reduction furnace 1 via the high temperature gas supply pipe 4 to perform preliminary reduction. The exhaust gas generated by preliminary reduction in the furnace is passed from the top of the furnace through an exhaust gas discharge pipe 8 to a dust collector 6, a heat recovery device 7, a decarboxylation device 9,
The gas is sequentially supplied to the first blower 10 and effectively used as a predetermined gas source. A part of the exhaust gas leaving the first blower 10 is
The gas passes sequentially through the second blower 22 and the exhaust gas property adjusting means 23 and is recycled into the preliminary reduction furnace 1 by the return gas supply pipe 21. On the other hand, iron ore that has undergone the prescribed preliminary reduction is
It is supplied from the extraction pipe 5 to the melting reduction furnace 3. At this time, the reduction rate of the iron ore discharged from the extraction pipe 5 is determined from the raw material condition measurement means 11, the first reduction reaction condition measurement means 12, the second reduction reaction condition measurement means 13, and the third reduction reaction condition measurement means 24. The calculation unit 17 that receives the predetermined output signals performs calculation processing based on these signals. The reduction rate is determined, for example, by the following formula.

Preliminary reduction rate - (ΔPe O) / (Po203) × 10
0% (ΔPe203): J: Measured value in 11a - Calculated value at outlet of preliminary reduction furnace (Pe O): Measured value in 11a above.If the calculated reduction rate is not within the predetermined value, the calculation unit 17 A signal corresponding to the reduction rate calculated by is outputted to the flow meter 23a and the flow rate adjustment valve 23b to change the flow rate and temperature of the exhaust gas recycled from the return gas supply pipe 21 into the furnace to predetermined values. Note that when calculating the return rate, the output signal of the flow rate side retirement stage 14 is taken into consideration as necessary. In this way, the reduction rate of the preliminary reduction furnace 1 is controlled to a predetermined value. As a result, the reduction rate of the preliminary reduction furnace 1 can be controlled to a constant value at all times, so that stable operation of the smelting reduction furnace 3 can be realized.

Incidentally, when the target reduction rate was set to 10% using the preliminary reduction smelting apparatus of the example and preliminary reduction was performed under the following operating conditions, the reduction rate calculated by the calculation unit 17 was 9.5%.
Met. Therefore, when a predetermined signal was output from the calculation section 17 and the supply amount of exhaust gas to be recycled was changed as shown below, a reduction rate (10.1%) approximately equal to the target value was obtained.

Operating conditions Raw material components Ore (T-P 67.0%, FeO5
%) Raw material supply amount 1678/l'g/H.

Composition of hot gas H2 (4,92%), H2O (21,42%).

Co (42,08%), Co2 (31,36%)
.

H2 (0,22%) Flow rate 1437N m3 Temperature 1800°C Components of exhaust gas H2 (7,89%), H2O (1[i, 83%).

Co (38,11%), C02 (37,15%
).

H2 (0,22%) Flow rate 2388N m3 Temperature 1150°C Components of recycled exhaust gas H2<14g32%), H2O (7,39%).

CO (29,65%), CO2 (48,42%).

N2 (0.22%) Flow rate 9 [1ONm.

Flow rate of recycled exhaust gas after change: 31 Nm3 Temperature: 40°C [Effects of the invention] As explained above, according to the pre-reduction smelting apparatus according to the present invention, the reduction rate of the pre-reduction furnace is always controlled to a constant value. By operating the melting reduction furnace in a stable manner, it is possible to operate the melting reduction furnace stably.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing one embodiment of a preliminary reduction furnace implementing the present invention apparatus and a control system for controlling its reduction rate to a predetermined value, and Fig. 2 shows another embodiment of the same control system. It is an explanatory diagram. DESCRIPTION OF SYMBOLS 1... Preliminary reduction furnace, 2... Raw material supply pipe, 3... Melting reduction furnace, 4... High temperature gas supply pipe, 5... Extraction pipe, 6... Dust collector, 7 ...Heat recovery device, 8.
... Exhaust gas discharge pipe, 9 ... Decarboxylation device, 10 ... Blower, 11 ... Raw material condition measuring means, 12 ... First
Reduction reaction condition measuring means, 13... Second reduction reaction condition measuring means, 14... Flow rate measuring means, 17... Arithmetic unit,
21... Return gas supply pipe, 22... Second blower 2
23... Exhaust gas property adjusting means, 24... Third reduction reaction condition measuring means.

Claims (2)

[Claims] (1) A pre-reduction furnace in which a predetermined raw material is fed into the hearth from a raw material supply pipe, a high-temperature gas supply pipe that supplies high-temperature gas from the melting reduction furnace to the pre-reduction furnace, and generation in the pre-reduction furnace. In a pre-reduction smelting equipment, which is equipped with an exhaust gas exhaust pipe that leads the heated exhaust gas to a heat recovery device, and a gas supply pipe that supplies the exhaust gas exiting the heat recovery device as a predetermined gas source, the high temperature gas supply pipe and the exhaust gas exhaust A reduction reaction condition measuring means is attached to each of the pipes to measure the composition, temperature, flow rate, and pressure of the gas flowing through these pipes, and a raw material supply pipe is used to measure the composition and supply amount of the raw material input from the raw material supply pipe. A condition measuring means is provided, and a calculating section is provided for calculating the reduction rate at the outlet of the preliminary reduction furnace based on the measurement signals from the reduction reaction condition measuring means and the raw material condition measuring means, and based on the output signal of the calculating section. A preliminary reduction smelting device characterized by controlling the reduction rate to a predetermined value by increasing or decreasing the amount of feed material. (2) A return gas supply pipe that recycles the exhaust gas exiting the heat recovery device and supplies it to the pre-reduction furnace; and a component of the exhaust gas that is supplied from the return gas supply pipe to the pre-reduction furnace based on the output signal of the calculation unit. 2. The preliminary reduction smelting apparatus according to claim 1, further comprising exhaust gas property adjusting means for adjusting temperature and flow rate.