JPS61204343A - Manufacture of sintered ore - Google Patents

Abstract

PURPOSE:To recover exhaust heat, diffused in the atmosphere, of a cooler mentioned below and latent heat of CO in exhaust mentioned below according to the scale and type of a continuous downward suction - type sintering machine, by subjecting exhaust from a sintered product cooler to which water is sprayed and evaporated for humidification to suction into a sintering bed. CONSTITUTION:In a sintering equipment consisting of a DL-type sintering machine 1 and a sintering product cooler, e.g., a circular suction-type cooler 2, water is sprayed to the exhaust from the cooler 2 for evaporation by use of a water sprayer 20 provided inside the duct. 19. Then the exhaust from the cooler 2 is humidified in the range where it is in an unsaturated state and exactly in a range where dew condensation does not come out on the surface of the sintering bed. the humidified exhaust is introduced into a hood 13, which is sucked into the sintering bed to manufacture sintered ore.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method for producing sintered ore, and more specifically, sintered ore can be obtained at low cost using a continuous downward suction type (DL2) sintering machine. The present invention relates to a method for producing sintered ore.

(Prior art) In a DL type sintering machine, as is well known, raw materials are charged into an endless chain-like pallet, and the surface layer of the raw materials is ignited in an ignition furnace, and the upper part of the raw materials is ignited by an exhaust fan through a wind box. By suctioning the air, the coke mixed in the raw materials is burned, and the raw materials are sequentially fired as the pallet moves. The firing of this raw material is completed before it reaches the ore discharge section, where it falls from a pallet and is discharged as one sintered ore.

The sintered ore discharged from the sintering machine is hot crushed, the powdered sintered ore is removed in a hot joint, and then sent to a cooler.
It is air-cooled in the air, and then crushed and sized.

The temperature of the hot crushed sintered ore is 80°C at the high part.
It is cooled to about 100 degrees Celsius or less using the above-mentioned cooler (cooler J), which heats the surface to protect the product processing and transportation equipment.The types of coolers are circular and linear depending on the shape. Depending on the ventilation method, there are push type and suction type.

However, the exhaust air from the sintered product cooler of the sintering machine contains heat Ti that is about 30% of the heat input to sintering, and the technology for effectively utilizing it is widely spread. Many different ones have been implemented. When steam is generated by a boiler and used, a steam pressure of 5 Kf/crt1 or more is usually required, so the exhaust temperature at the exit side of the exhaust heat recovery equipment must be at least 150°C or higher. In this case, the exhaust temperature at the entrance of the exhaust heat recovery equipment will vary depending on the amount of recovered heat, but it is usually between 250 and 300.
Exhaust heat with a temperature above ℃ and below that temperature is not subject to steam recovery.

Another method of utilizing the exhaust heat from a sintered product cooler is to use the exhaust air from the cooler directly as combustion air for the sintering ignition furnace, or as air for preheating and drying compounded raw materials. In this case as well, the temperature of the recovered exhaust gas from the sintered product cooler is generally 150° C. or higher.

(Problems to be Solved by the Invention) As mentioned above, the exhaust gas from coolers for sintered products at temperatures below 150°C was not effectively utilized and was dissipated into the atmosphere.

Therefore, the present invention newly recovers the exhaust heat of the cooler, which was conventionally dissipated into the atmosphere, depending on the scale and model of the sintering machine.
At the same time, this also recovers the latent heat of CO in the sintering main exhaust gas, which was conventionally dissipated into the atmosphere unused, and reduces coke breeze consumption without deteriorating the yield and quality of sintered ore. In particular, it provides a method for producing sintered ore at low cost.

(Means for Solving the Problems) The present invention employs a continuous downward suction sintering machine in which exhaust air from a sintered product cooler, which is humidified by spraying and evaporating water, is sucked into the sintering bed for sintering. The main feature lies in the manufacturing method of sintered ore.

The present invention will be explained in detail below.

Most of the heat required for calcination of sintered ore is supplied by the combustion of coke breeze in the blended raw materials. It is well known that the amount of heat generated by combustion of coke breeze per unit amount of blended raw materials is determined by the blending ratio of coke breeze in the blended raw materials and combustion.

The relationship between and the calorific value of coke powder is shown.

The present inventors believe that this complete combustion rate is strongly controlled by the moisture in the air sucked into the sintering bed, as shown in Figure 1, and that in order to improve the complete combustion rate and increase the calorific value, sintering New findings have been obtained that increasing the moisture content of the sucked air is effective.

The present invention has been made based on this new knowledge.

FIG. 3 is an explanatory diagram of an embodiment of the present invention, in which the sintering equipment consists of a 1DL type sintering machine 1 and a sintered product cooler such as a circular suction cooler 2, 3 is a pallet, 4 is a bedding hopper, 5 is a blended raw material surge hopper, 6 is an ignition furnace,
F is a wind box.

8 is a main exhaust pipe, 9 is a dust collector, 10 is a main exhaust fan, 11 is a chimney, 12 is a sintering bed formed on the pallet 3, 13
is the sintering bed 12 in the coke breeze combustion range behind the ignition furnace 6.
It is a hood placed above the hood.

14, 15, and 16 are crushers, screens, and feeders installed between the ore discharge section of the pallet 3 and the ore supply section of the sintered product cooler 2; 17 is the ore discharge section of the cooler 2;
On the 1st, a cooler blower is used, and on the 19th day, the exhaust air from the sintered product cooler where the atmosphere and high-temperature sintered ore have exchanged heat is
It is a duct leading to.

In such a sintering facility, a water header pipe 21 installed inside the duct 19 is provided with a plurality of water spray nozzles 22'! ! - The installed water spray device 20 sprays and evaporates water to the exhaust air of the sintered product cooler within an unsaturated state, specifically within the range where dew condensation does not occur on the sintering bed surface. humidify.

(Example) In a DL type sintering machine, the exhaust of the sintered product cooler (02
21%, moisture 2'Of/Hv? , temperature 150°C) and evaporated water (temperature 20'C) to 40f/I Jr.
r? Sintered ore is produced by sucking the humidified exhaust air from the sintered product cooler (0.21%, humidity 60 f 71 m'', temperature 70°C immediately after humidification, temperature 50°C on the surface of the sintering bed) into the sintering bed. Note that the saturation temperature of the exhaust air (suction air) of the sintered product cooler with a moisture content of 60 °C was 43°C, and there was no condensation on the sintering bed.

As a result, the proportion of coke powder in the blended raw materials was 3.0%.
Under certain conditions, it is possible to improve the combustibility of coke breeze.
Fe2 in the product increased, and the cold strength and product yield were improved (Case AJ).Also, if the coke breeze blend was reduced by the amount of coke breeze combustibility improvement effect, the product FeO level increased. It was possible to maintain the cold strength and product yield at a constant level (Case B).

Table 1 (Effects of the Invention) According to the present invention, the waste heat of the sintered product cooler, which was conventionally dissipated into the atmosphere, can be recovered depending on the scale and type of the sintering machine. It is possible to recover the latent heat of CO, which is the main component of sintering, and which has been dissipated unused in the sintered ore, reducing the coke breeze consumption rate without deteriorating the yield and quality of sintered ore, resulting in low cost. Sintered ore can be produced.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between moisture in the sintering bed suction air and COv'00 + 002σρ in the flue gas from coke breeze combustion.
Figure 2 shows OOvlo O+ in coke breeze combustion flue gas.
002 (%) and the calorific value of coke powder, FIG. 3 is an explanatory diagram of an embodiment of the present invention. l...DL type sintering machine 2...Sintered product cooler 19...Cooler exhaust duct 2o...Water spray device 13...Hood application People Nippon Steel Corporation Figure 1

Claims (1)

[Claims] A method for producing sintered ore, characterized in that, in a continuous downward suction type sintering machine, exhaust air from a sintered product cooler, which is humidified by spraying and evaporating water, is sucked into a sintering bed for sintering.