JPH0777390A - Method and apparatus for treating substances such as rolling scale containing oil - Google Patents

Abstract

(57) [Abstract] [Purpose] To make it possible to purify rolling scales with a dust filter device while saving energy and without risk of fire. Furthermore, the energy of oil contained in substances such as rolling scales can be used. [Structure] A continuous heating furnace (12) is connected via a pipe (23).
Hood (11) on the hot part of the sinter cooler (5)
It can be heated by the hot exhaust air from
By communicating with the ignition furnace (3) of the sintering machine (1) via 4), the hot exhaust air of the sintering cooler (5) is introduced into the ignition furnace (3) as combustion air.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for treating a substance such as a wet rolling scale containing oil, which is designed to remove oil from a substance such as a rolling scale containing oil at a high temperature in a continuous heating furnace. It is about.

[0002]

BACKGROUND OF THE INVENTION Rolling scale and its sludge occur in rolling mills when the scale layer is removed prior to the rolling process. The rolling scale is, for example, iron oxide that can be fed back into the raw material in the sintering device. In the rolling mill, the scale mixes with cooling water or water used as pressure water for blowing off the scale layer by jetting, and also with oils or oils used, for example, for lubricating bearings. It is possible to separate relatively large pieces of the rolling scale in a purification device that purifies the circulating water of the rolling mill, but it is not possible to completely remove the oil. Small pieces of rolling scale can be removed from the circulating water to some extent by sedimentation, but the rest are removed by a filter. These small pieces have a water content of less than 30% and an oil content of 6%.
Form rolling scale sludge of less than a few percent. The use of rolling scale sludge during sintering not only evaporates water, but also renders at least a portion of the oil non-combustible. Part of the oil component condenses in the electronic filters commonly used today. The purpose of using the electronic filter is to purify the smoke gas of the sintering machine to contain the minimum content of dust specified by law. However, if the smoke gas contains a large amount of organic material, a fire may occur, and in an extreme case, an explosion may occur in the filter. This is easily caused by electrical flashover between the scattering and precipitation electrodes of the electronic filter. The condensed oil component makes it difficult to clean the precipitation electrode, and the unseparated oil indirectly interferes with the function of the electronic filter, and directly by the condensed atomized oil,
It makes the emitted smoke gas turbid.

Kilman and Sherberg reported at the Duisburg Recycle Convention (1988) on the processing of rolling scales. The idea lies in two-layer sintering, which is first ignited, on top of the first lower sintering mixture layer which does not contain rolling scale sludge.
It is to apply another layer of rolled scale sludge containing oil. This further layer is separately fired at the appropriate time. Oil is discharged from the upper layer and burns as it passes through the lower layer. However, this method cannot be carried out without maintaining strict process conditions, and a considerable improvement in the sintering equipment is required for application to the existing sintering equipment. Furthermore, they said that the rolling scale sludge in the furnace heated by the mixed gas of coke gas and air was released from the oil when the temperature reached above 100 ° C, and the initial oil content was 7%. If so, the temperature is 2
It is reported that the oil can be reduced by at least 0.1% when the temperature exceeds 80 ° C.

Industrial equipment such as blast furnaces and steel mills often discharge oil-containing substances such as sand. It is difficult to remove oil from such materials and they are therefore transported to special landfills. Therefore, the processing of substances containing oil is extremely troublesome. For this reason, it is desirable to be able to remove oil from such substances with a simple device, even if the substance containing oil is not charged into the blast furnace.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to improve a method and apparatus for removing oil from oil-containing solids such as rolling scale, and particularly rolling scale sludge, by rolling: To improve the scale so that it can be cleaned with modern dust filter devices, which is energy-saving and without fire hazard. Another object of the present invention is to make it possible to utilize the energy of oil contained in substances such as a rolling scale.

[0006]

In order to solve the above problems, the present invention provides, in a method, a treatment of a material such as a rolling scale in association with an iron ore sintering apparatus, and a hot discharge from a sintering cooler. The air is withdrawn and fed into a convection through a material such as a fed scale, in which the material is dried and at least part of the oil is burnt, then containing a moist, volatile oil. The exhaust air present is charged as hot combustion air into the ignition furnace of the sintering apparatus, and at that time, the remaining oil is burned in the ignition furnace.In the apparatus, the continuous heating furnace uses a pipe. The hot exhaust air from the hood above the hot part of the sinter cooler, and by communicating with the ignition furnace of the sinter machine via a tube, the hot exhaust air of the sinter cooler To the ignition furnace as combustion air It is characterized in that so as to.

According to the invention, rolling scales which are as free of water as possible and which are normally free of foreign matter are treated, which in some cases may be present as rolling scale sludge. . In this case, in some cases, the co-sintered pieces are pre-milled,
It is burned in a continuous furnace at a temperature such that moisture and volatile oils can be removed and the remaining oil is optionally treated by cracking. This treatment is performed directly in connection with the iron ore sintering device.

It is a known technique to recover the hot exhaust air coming out of the chiller of a sintering machine, especially in the first part, and to use it. This exhaust air is often charged as preheated combustion air into the ignition furnace of the same sintering machine.

According to the invention, the hot exhaust air of the chiller is fed to a continuous heating furnace in which the hot exhaust air and the oil-containing solid matter such as rolling scale are guided in the convection of the continuous heating furnace. To be done. Exhaust air that evaporates and absorbs partly burned oil leaves the continuous heating furnace, but since moisture is removed from the rolling scale and it is heated, the exhaust air only corresponds to the flow state of heat capacity. To be cooled. However, since the exhaust air still contains a considerable amount of heat, it is supplied as preheated combustion air to the ignition furnace of the sintering device. Here, the unburned part of the oil burns with heat of 1000 ° C. or higher. This unburned part of the oil comes from the continuous heating furnace together with the combustion gas and is thermally released from the solid substances such as the rolling scale in the continuous heating furnace. The high combustion temperatures and, if small, small amounts of oxygen in the ignition of the sintering machine ensure complete combustion of the oil. Therefore, the load on the smoke gas filter of the sintering machine due to oil is avoided. The heating value of oil is fully utilized in the continuous heating furnace (part of the oil burns) and the ignition furnace (the rest of the oil burns).

In a preferred method of processing rolling scales, hot, dry, thermally oil-free rolling scales coming from a continuous heating furnace are fed to a recovery product, for example a hot recovery product, via a discharge line, In the process, it reaches into the iron ore mixture to be sintered. The rolling scale can also feed the mixture of iron ores directly, bypassing the recovery stream. This facilitates control of the sintering machine in keeping balance between the production and input of recovered material. The heat content of the hot rolling scale is introduced into the mixture of iron ores, except for the unavoidable losses during transport. Therefore a mixture of iron ores
It is preheated according to the heat quantity ratio and quantity ratio of the rolling scale and the iron ore mixture, and reaches below the ignition furnace of the sintering device. Therefore, most of the heat coming out of the continuous furnace is utilized with the hot rolling scale.

When treating other oil-containing substances, such as sand, oil can also be removed from the sand by introducing hot exhaust air of the sintering chiller into the ignition furnace of the sintering machine. . However, in general, the dry sand released from the oil is not fed to the sinter and is removed from the sinter's material stream in the absence of oil. In general, sand does not meet the requirements of iron ore mixtures to be processed in sintering equipment in terms of material and time.

According to the structure of the present invention, the rotary kiln is used as the continuous heating furnace. Alternatively, a hierarchical kiln, which is often used in roasting iron ores containing sulfur, may be used. Both are suitable for convection between the hot exhaust air of the cooler and the rolling scale containing moist oil.

Since the properties of the rolling scale are not constant (humidity varies considerably; feed particles differ; oil content varies), the feed of the rolling scale to the continuous heating furnace is discharged to the ignition furnace. It is controlled according to the temperature of the supplied exhaust air. In this way, the ignition furnace can be operated in a steady state. The residence time of the feed in the continuous heating furnace is advantageously up to 30 minutes. When the treatment time was examined experimentally, this residence time was sufficient.

When the temperature of the air discharged from the cooler is lower than a predetermined limit value, for example, 350 ° C. or higher, the supply of a moist rolling scale sufficiently containing oil is interrupted. Furthermore, in order to control the purification function of the continuous heating furnace, the temperature of the hot rolling scale discharged from the continuous heating furnace is optically measured, for example, by infrared rays, and if this temperature is below the limit value, the continuous heating furnace It is advantageous to interrupt the supply of moist rolling scale to the. The hot exhaust air of the cooler is directly burned through the continuous heating furnace by using the slider valve and the supply pipe so that the maintenance work of the continuous heating furnace can be performed even while the sintering device is operating. The purpose is to supply to. In front of the ignition furnace, it is advantageous to provide a cyclone for removing dust. The hood for collecting the hot exhaust air of the cooler is equipped with a safety device for blowing this exhaust air.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

The pretreated mixture is supplied to the sintering machine 1 and the bed transfer stoker via the supply device 2. The mixture is ignited in the ignition furnace 3 by the ignition gas of the coke contained in the mixture. The sintered mass is crushed by the spike crusher 4, reaches the sinter cooler 5, and is supplied to the cooling air via the blower 6. The finished sintered product is sent to the blast furnace through the transfer path 7 after measuring the diameter and filtering (not shown). The smoke gas emitted from the sintering machine 1 is sucked by the blower 9 through the electronic filter 8 and discharged through the chimney 10. From the hot part of the sintering cooler 5, hot exhaust air of the sintering cooler 5 is discharged through the hood 11 and reaches the continuous heating furnace 12. The rolling scale to be treated flows in the continuous heating furnace 12 in convection. The exhaust air from the sinter cooler 5 that has cooled at this point reaches the dust separator 13 from the continuous heating furnace 12 and reaches the inside of the ignition furnace 3 as hot combustion air by the blower 14. This combustion gas contains smoke gas composed of oil burned in the continuous heating furnace 12 and a volatile low boiling point component contained in this oil. This component burns in the ignition furnace 3 at a temperature of 1000 ° C. or higher.

The rolling scale is supplied to the continuous heating furnace 12 by an appropriate conveyor 15 whose transfer amount can be adjusted. The hot scale, which is thermally released from the oil, is mixed with the mixing device 17 via, for example, an exhaust furnace 16 or other suitable conveying device.
Sent to. Ore, aggregate, and pulverized coal are mixed in the mixing device 17. The mixed sinter 17 may be charged with the recovered sinter after the separation of the finished sinter after the sinter cooler 5 and the transfer device 18. The rolling scale from which the oil has been separated may be directly added to the recovered sintered product. The mixture flows through a rotary mixing drum (not shown) to reach the feeding device 2.

A hot, dry rolling scale heats the mixture. The hot exhaust air coming out of the sinter cooler 5 cools during the drying of the moist rolling scale, but the continuous heating furnace 12
It is heated again by the partial combustion of oil in the ignition furnace 3
To supply the remaining volatile oil as another fuel.

Considering the amount of heat required for drying, the amount of heat required for purifying oil by heat, the amount of heat for heating the rolling scale, and the heat value of oil and the air demand of the ignition furnace of the sintering machine. This gives the maximum amount of rolling scale that can be processed in the sintering machine. This maximum amount is not constant because the characteristics are not uniform as described above. The following is an example. Table 1 Ignition air demand of sintering equipment: 5000 m ³ / h Ignition air temperature: 300 ° C Sintering equipment throughput: 5500 t / day Cooler exhaust air: 400 ° C Rolling scale humidity: 10% Oil heating Value: Not taken into account Rolling scale supply temperature: 20 ° C Rolling scale discharge temperature: 370 ° C Rolling scale throughput: 27 t / day Maximum throughput possible by lowering the ignition air temperature of 300 ° C to a lower temperature Will increase. For example, if the ignition air temperature is 200 ° C., 54 t of rolling scale can be processed per day. As the ignition gas in the ignition furnace 3, the furnace port gas from the pipe 18 is usually used. The combustion gas is preheated depending on the throat gas used. With the device according to the invention, it is not necessary to separately heat the combustion air beforehand.
This is because sufficiently hot exhaust air from the sinter cooler 5 is used. The above example shows the relationship between the temperature of the ignition air and the possible throughput of the rolling scale by the continuous heating furnace.

Since the composition of the rolling scale is different,
It is advantageous to monitor and control the temperature. Temperature measuring instrument 1
9 detects the temperature of the exhaust air from the sintering cooler 5 supplied as the combustion air, and restricts or stops the supply of the rolling scale to the continuous heating furnace 12 via a control device (not shown). Alternatively, the exhaust air from the sintering cooler 5 is sent to the bypass 20. The temperature measuring device 21 is the sintering cooler 5.
The temperature of the hot exhaust air from is measured, and when this temperature falls below a predetermined value, similar control is performed. Further, the temperature of the rolling scale behind the continuous heating furnace 12 may be monitored by the temperature measuring device 22. In this way, sufficient thermal purification can be performed. The above-mentioned temperature measuring device and other control devices of the sintering device can be linked via a computer which creates the optimum conditions in the method.

Next, embodiments of the present invention will be listed.

Process according to claim 1, characterized in that (1) the rolling scale, which has been thermally purified by oil, is ignited in the mixture for the sintering device.

(2) A rolling scale thermally purified with oil is ignited to a sinter recovery product, and the sinter recovery product is charged into a mixture for a sintering apparatus together with the sinter recovery product. The method according to 1.

(3) The temperature of the exhaust air from the sinter cooler that flows into the ignition furnace as combustion air is monitored, and the throughput of the rolling scale by the continuous heating furnace is controlled to maintain a predetermined temperature value. Method according to claim 1, said first or second claim, characterized in that

(4) The processing time of the rolling scale in the continuous heating furnace is about 30 minutes at the maximum, and the rolling scale according to any one of claims 1 to 3 is used. The method described.

(5) The exhaust air from the sintering cooler at a temperature of at least 350 ° C. is introduced into a continuous heating furnace, or any one of claims 1 to 4 above. The method according to one.

(6) Continuous heating furnace (1) for treating air discharged from the sintering cooler and substances such as rolling scale in convection.
The processing time of 2) is about 30 minutes,
The device according to claim 2.

(7) The apparatus according to item 6, wherein the continuous furnace (12) is a rotary kiln.

(8) The apparatus according to item 6 above, wherein the continuous furnace (12) is a hierarchical kiln.

(9) A conveying device (16) is provided for feeding the hot-rolled scale from the continuous heating furnace (12), released from oil, to the mixture. Alternatively, the device according to any one of items 6 to 8 above.

(10) A pipe (24) is provided with a temperature measuring device (19) for measuring the temperature of the combustion air, and a continuous heating furnace for substances such as rolling scales is provided through the temperature measuring device (19). Device according to claim 2 or any one of claims 6 to 9, characterized in that the supply to 12) is controllable.

(11) A temperature measuring device (21) for measuring the temperature of hot exhaust air from the sintering cooler in the pipe (23).
And the temperature measuring device (21) interrupts the treatment in the continuous heating furnace (12) when the temperature is insufficient. 1
The apparatus according to any one of paragraphs 0.

(12) On the discharge side of the continuous heating furnace (12),
Continuous heating furnace when the temperature of the material to be treated is low (12)
3. A temperature measuring device (22) is provided which reduces or interrupts the supply of said substance to.
Alternatively, the apparatus according to any one of items 6 to 11 above.

[0034]

According to the present invention, a rolling scale can be cleaned with a recent dust filter device while saving energy and without risk of fire. Further, the energy of oil contained in substances such as a rolling scale can be used.

[Brief description of drawings]

1 is a block diagram of an apparatus according to the present invention.

[Explanation of symbols]

 1 Sintering machine 3 Ignition furnace 5 Sintering cooler 11 Hood 12 Continuous heating furnace 23, 24 tubes

Claims (2)

[Claims] 1. A method for treating a substance such as a wet rolling scale containing oil, wherein the oil is removed from the substance such as a rolling scale containing oil at a high temperature in a continuous heating furnace. The treatment is carried out in connection with an iron ore sinter device, in which hot exhaust air is removed from the sinter cooler and fed into the convection via the material supplied, such as the rolling scale, to dry the material and oil. At least part of which is then burnt, and the exhaust air containing moist, volatile oil is then introduced as hot combustion air into the ignition furnace of the sintering device, the remaining oil being left in the ignition furnace. A method of treating, characterized in that: 2. For treating a substance such as a wet rolling scale containing oil with a hot gas in a continuous heating furnace,
An apparatus for performing the method according to claim 1, wherein
A continuous furnace (12) is heatable by hot exhaust air from a hood (11) above the hot part of the sintering chiller (5) via a pipe (23) and a pipe (24). The hot exhaust air of the sintering cooler (5) is introduced as combustion air into the ignition furnace (3) by communicating with the ignition furnace (3) of the sintering machine (1) via the And the device.