JPS60106927A - Production of sintered ore - Google Patents

Abstract

PURPOSE:To improve air permeability of a sintering raw material layer and to increase productivity as well by supplying the middle-temp. waste gas which is discharged from an apparatus for producing sintered ore and is subjected to heat recovery in a boiler and the middle-temp. waste gas after cooling of the sintered ore to the crude raw material part of a sintering raw material. CONSTITUTION:The coke in the sintering raw material layer 5 on a pallet 4 of a DL type sintering device is ignited by an ignition device 6 and as said layer is moved rightward by a pallet 4, the sintering raw material is sintered. The high temp. waste gas of 350-500 deg.C discharged from the sintering machine is recovered of sensible heat in a boiler 26 and is supplied as the relatively middle- temp. waste gas of 150-250 deg.C via a conduit 29 to an ignition furnace 6 by a suction blower 27. The cooling waste gas from a cooler 12 for the sintered ore has also the middle temp. of 150-250 deg.C and is therefore supplied via a conduit 30 to the furnace 6. These gases are blown into the wet sintering raw material by which the heat contained therein is recovered. The CO2 in the gases reacts with the Ca(OH)2 in the raw material to form CaCO3 which forms secure pseudo particles. The air permeability of the layer 5 is thus improved, the rate of sintering is increased and the productivity of the sintered ore is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for producing sintered ore, in particular, in which the exhaust heat of the sintering machine exhaust gas is recovered by a boiler, etc., and the recovered exhaust gas and other medium-temperature exhaust gas are further utilized for sintering, and The present invention relates to a method for producing sintered ore that improves the air permeability of sintered ore and improves sintering performance.

In general, a continuous dotroid (DL) sintering machine, which is suitable for mass production, is often used to produce sintered ore as a raw material for blast furnace charging. In addition, the sintering machines include linear DL type and circular D type.
There is an L type, but generally it is a linear type DL as shown in Figure 1.
formula is adopted.

FIG. 1 is a schematic diagram showing a method for producing sintered ore using a conventionally known linear type 1) I sintering machine.

In FIG. 1, 1 is a bedding raw material hopper, 2 is a mixer equipment for main raw materials such as iron ore, fusix, coke, etc., and 6 is a main raw material hopper.

These raw materials are charged onto the moving grate 4 to form a sintered raw material layer 5. Next, the raw material layer 50 is
The surface is uniformly ignited, and sintering and firing is performed in the order of ignition → sintering → cooling from the surface of the ore layer downward as the movable grate 4 moves.

Reference numerals 10 and 11 are a gas blower for the ignition furnace and an air blower for the fuel #L.

The movable grate 4 has a drive device (not shown) on the ore feeding side, which drives the pallet by the engagement of a tin rocket wheel 15 and a roller attached to the pallet body.On the ore discharge side, the pallet is returned. The sintered ore is discharged to a sintered ore cooling cooler 12, and the sintered ore is forcibly cooled by a forced float 13 in the cooling cooler. 14 is an ore discharge chute cover. These pallets can only be returned using a track guide or a sprocket foil 1.
This is done using a method that combines steps 5 and 5. The exhaust gas generated by the sintering reaction is transferred to the main exhaust gas tact 1 through the wind box 16.
After that, the dust is appropriately removed by an electric precipitator 18, and then sucked by a blower (not shown), and then passed through a desulfurization facility (III+19) and a denitrification facility 20, and then into the atmosphere from a chimney 21 to II"A. 22 shows the amount displayed on the wind box.

In recent years, from the viewpoint of effective energy use, in the production of sintered ore such as Slope, exhaust gases generated during various sintering processes, such as exhaust gas from the discharge side of sintered ore or exhaust gas from coolers for cooling sintered ore, have been exhausted. A method is being developed to utilize waste heat by introducing it into hot gas recovery equipment. Also, JP-A No. 53-76103 or JP-A No. 5
Publication No. 3-125905 describes equipment or a sensible heat recovery method for circulating a part of the sintering machine Ku2 exhaust gas to the ignition furnace and the heat retention and combustion zone above the sintering machine and using it as heat retention combustion air. is disclosed.

Furthermore, 1 jl of sintered U1 ore is disclosed in JP-A-56-166338.
JP-A-56-30681 discloses a sensible heat recovery method in which waste heat is recovered from exhaust gas as well as cooler exhaust gas using a waste heat boiler, and the recovered exhaust gas is recirculated in the sintering process. In the firing process, the oxygen concentration in the v1 gas is 10
A method for sintering fine ore is disclosed in which the exhaust gas, which is mainly leakage, is reused in the sintering process and oxygen is added thereto. Examples of methods for treating furnace and condensed exhaust gas are also disclosed in the above-mentioned articles.

However, the above-mentioned patents merely aim to recover vF heat or recover waste heat.

In view of this, the object of the present invention is to remove the sintering machine 117. (1) Temperature range of 150 to 2 b O generated from the sintering machine in a sintering facility equipped with equipment to recover the red and white heat of 350 to 500 °C gas generated from the sintering machine using a boiler.
“C exhaust gas (vortex gII after being treated with the above boiler)>
, containing antagonistic gas at a temperature range of 150 to 250 °C) and p1, which is also generated from a sintering cooler and has a temperature range of 150 to 250 °C.
The gas is circulated in the first half of the firing process of the raw material on the sintering machine, in other words, in the raw material wet zone, and the temperature is kept at 150.
Recover Fi heat from Nakafuchi exhaust gas at ~250°C.

(2) The following carbonation reaction occurs between CO2 in the circulating exhaust gas and Ca(OH)2 in the aggregated particles present in the raw material wet zone, resulting in Ca (()H)2+cO2-+ CcCO=, +H2
The aggregated particles, which are a combination of ore, coke, and lime, form a stable and strong combination, and the permeability of the raw material layer is significantly improved. The combustibility in the process is improved, which improves productivity as well as yield. This great benefit is expected.

(3) Input the wind box wind seal, the temperature inside the ignition furnace, the air permeable material bed height of the same-pressure bucha raw material, the properties of the components, the sintering machine speed, etc. into the computer, perform the predicted motilization calculation, and save the data. By controlling the output, optimum combustion speed, exhaust gas flow rate, and raw material bed height, we can always achieve stable operation and high quality products in accordance with the fluctuating raw material properties.

The gist of the present invention is the intermediate part of the sintering machine, the post-cooling part of the sintered ore, and the sintering machine. 1eat gas heat recovery equipment Unbalanced heat recovery equipment 0 to 250℃ medium temperature 1. A method for producing sintered ore characterized in that gas is supplied to the raw material in front of the sintering machine ignition furnace, the ignition furnace heat retention furnace, and the front part of the sintering machine and used for sintering.

That is, the present invention enables the raw material 5 on the sintering machine, which has conventionally been released into the atmosphere, to be released into the atmosphere.
The main exhaust gas generated from the sintering process and the gas generated from the sintered ore cooling cooler 212 [temperature 8 [range 1ij 150 to 250
℃ medium-temperature exhaust gas" in the sintering machine upper ignition furnace 7, 8.9 and the firing process of the sintering machine upper raw material 5. By recycling and reusing the air, empty cartridges for furnace firing (marker thickness 9.20°C), which were conventionally sucked naturally by the combustion air blower 11 or surrounding people, can now be
By replacing the exhaust gas with a temperature of ~250℃ (16~21% of carbon content), the input heat for the evaporation of moisture in the raw materials, sintering, and heat is increased, and the fuel consumption rate of the ignition combustion gas is reduced. , a decrease in the flour coke unit in the original phase is oJit;

This effect is achieved in a sintering machine with a grate length of about 400 m, with 15 to 2
It is possible to use 4# gas that reduces to 00,000 Nrri'/l+, and the sensible heat recovery in that case is 1.328k
(”/'N+++'X (15~20) X 10
Nm7HxO: 34X[<15[)-250°C
)72LJ”C,]=881)2260.TIka4/
H's hot episode 11! It is expected that v.

FIG. 2 is an explanatory diagram for showing an embodiment of the present invention. The same special feature as the first one indicates the same function.

In FIG. 2, the raw material ore layer 5 on the moving grate 4 has almost completed the sintering reaction and moves to the cooling zone on the ore discharge side. An exhaust heat boiler 26 is provided to recover the sensible heat of the exhaust gas from the exhaust ore side. recovered as electrical energy. The temperature of this waste heat boiler exhaust residue is still 150 to 250℃.
Gas pipe 2 to the wet zone of the raw material above the furnace 4
9.

On the other hand, the second half of Haikeiko's cooling cooler 12? Cooling exhaust gas is also 15
0 to 25υ0 (), it is circulated and recovered to the decommissioning furnace zone via the gas pipe 60. Although the intermediate temperature exhaust gas in the middle part of the 10-terminal is not shown in the figure, it is circulated and recovered in the same way as the above-mentioned Chukyo exhaust gas. do.

These recovered exhaust gases are circulated to the furnace preheating zone 7, the ignition zone 8, and the combustion heat retention zone 9, respectively, and the exhaust heat boiler exhaust gases are circulated through the conduit 29 through the respective control valves 24-7, 24-s. , 24-q, and the sintered ore cooling cooler exhaust gas is used for controlled circulation from the conduit 30 through the circulating exhaust gas flow rate control valves 25-y, 25-s, and 25-9K. The gas passes through the raw material layer 5 of the sintering machine, passes through the wind box 16 and the main exhaust gas duct 17, is subjected to pollution prevention treatment by the air dust collector 18, desulfurization and denitrification equipment 19 and 20, and is released into the atmosphere from the chimney 21. be done.

As mentioned above, by blowing circulating exhaust gas into the raw material wet zone, the coagulated particles (fine ore, coke powder, mixture of lime and water) existing in the wet zone of the sintered raw material are generated, and the coagulated particles are It is hardened and bonded by stronger Ca CO1. As a result, the permeability of the sintered raw material layer is improved, the combustion rate is increased, and productivity is improved.

Next, a combustion control mechanism is an indispensable feature of the structure of the present invention. The raw material for sintering is, as is the case in Japan, a wide variety of types of powdered stone, which are produced each time by changing the blending ratio of various raw material brands, depending on the requirements of the subsequent blast furnace process.

As described above, the properties of the sintering raw materials are constantly changing due to variations in the degree of mixing of the raw materials, changes in the blending ratio of brands, changes in moisture content, etc. In response to this variation in raw material properties, the present invention has a control mechanism to always obtain optimal yield, quality, and high productivity.

Measure the air volume and ventilation of each wind box 16 (representing pressure, temperature, temperature inside the ignition furnace, pressure inside the furnace, raw material quality, analysis data, sintering machine rotation speed (pallet speed), and input the data. Based on the prediction model of the computer 23, the optimum S and landscape pattern of each wind box and the optimum air volume distribution of the ignition furnace preheating zone 7, ignition zone 8, and combustion heat retention sea 79 are determined. 16 landscape adjustment dampers and air volume adjustment dampers for each zone of the ignition furnace 247=n, 2
It has a mechanism for controlling 57 to 9, and is capable of stable operation and high quality production. The optimal landscape distribution prediction model is shown below.

That is, FIG. 6 is an explanatory diagram for calculating the prediction model in the explanation part of the measurement point for inputting into the calculation board and adjusting and controlling the plowing gas amount in the present invention. Further, FIG. 4 is an explanatory diagram showing, as an example, the air volume distribution in the direction of the sintered strand and the firing process in the sintering bed (inside the raw material layer). ,14 The raw materials on the sintering machine are moistened, dried, burned, melted, red-hot heat-retained,
Firing is completed after cooling.

The optimal landscape distribution model predicts the air volume distribution in the 2/2 direction, that is, the air volume distribution and temperature distribution of each wind box, using a mathematical model. Standard value for each C11'+: Raw material property coefficient C5: Sintering speed coefficient 1'a: Demonstration at α point at temperature change 0 to P (1
It is a function of temperature. As shown in the above formula, Fig. 4 f * A + I' + α
The prediction of the wet zone indicated by the area of By using a correction function based on the exhaust gas temperature in the ignition furnace, it is possible to determine the appropriate amount of circulating exhaust gas in the ignition furnace.

Note that the 0 point is the length of the wet zone (Fig. 4 1i-a), which depends on the raw material conditions, sintering: operating conditions, etc., so the temperature at multiple points is actually measured to determine the relationship. As an example, It is also possible to make predictions based only on temperature changes from 0 to F among a plurality of α points.

The present invention uses the predictive mathematical model of the wet zone as well as the actual measurement data of the exhaust gas wind 1, temperature, and pressure in each wind box (5 boxes), the property data of the raw material, and the sintering process as shown in Figure 4. Using data such as the machine pallet speed, temperature inside the ignition furnace island, and pressure as an index, the moisture completion point α and the drying completion point are determined by a mathematical model.

Combustion completion point C2 Melting completion point d, red heat insulation zone e, 伶”#
It is a sintering control system that predicts rf etc. from computer calculation results and feeds it back to the sintering operation as shown in Figure 3.It is a sintering control system that achieves high quality and high productivity through the optimal air volume pattern for hunting and the optimal firing process. be.

As shown above, the present invention circulates the exhaust gas after extraction heat recovery from the conventional sintering machine middle section, the exhaust heat recovery equipment, and the intermediate temperature exhaust gas from the sintered ore cooling cooler to the wet zone raw material layer in the first half of the sintering machine. By using this, the air permeability of the lung debris during sintering and firing can be significantly improved, and when using these materials for circulation, it is important to consider the air flow, temperature, and raw material properties at several locations after the sintering machine. Furnace temperature and pressure are input into a computer, the optimal air flow distribution is predicted and calculated, and control is performed based on the results. Unlike conventional heat recovery, this productivity improvement effect can increase production by 5.
This is equivalent to ~10%, and for a sintering machine with a grate area of about 400 mm, a great benefit is expected, which is equivalent to 4 to 5 billion yen per year.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a conventional sintered ore manufacturing method, Fig. 2 is an explanatory diagram of a sintered ore manufacturing method according to the present invention, and Fig. 3 is an illustration of measurement points for predictive model calculation by a computer according to the present invention. The explanatory diagram, FIG. 4, is an explanatory diagram of the optimum air volume distribution prediction model. 2...Main raw material mixer equipment 4...Movable grate 5.
... Sintering raw material layer 6 ... Ignition furnace 7 ... Ignition furnace preheating zone 8 ... Ignition zone 9 ... Combustion heat retention zone 1U ... Gas blower for ignition furnace 11 ... Air for combustion Prower 12...Sintered ore cooling cooler 16...Wind box 17...Main exhaust gas duct 21...Chimney 23...
・It
・Exhaust heat recovery suction blower 29, 30... Circulating exhaust gas gas pipeline agent Patent attorney Sanro Kimura

Claims (2)

[Claims] (1) Medium-temperature exhaust gas of 150 to 250°C from the middle part of the sintering machine, the latter part of the cooling cooler for sintered ore, and the sintering machine gas exhaust heat recovery equipment is used as raw material in front of the sintering machine ignition furnace, A method for producing sintered ore that is supplied to the front part of a heat furnace and sintering machine and used for sintering. (2) Determine the respective values of the silent air volume, temperature, raw material layer permeability, raw material properties, ignition furnace temperature, pressure inside the ignition furnaces, sintering machine pallet speed, etc. at multiple locations in the sintering machine. The method is characterized in that the amount of medium-temperature exhaust gas is input into a computer, and the computer predicts and calculates the optimal Jjil amount distribution, and controls the amount of medium-temperature exhaust gas supplied to the main raw material before the ignition furnace, the ignition furnace, and the front half of the sintering machine. A method for producing sintered ore according to claim 1.