JPS58207307A - Production of sponge iron - Google Patents

Abstract

PURPOSE:To improve thermal efficiency in a method for production of sponge iron wherein a raw material and a reducing agent are calcined by utilizing the coolng air and waste gas of a tunnel type calcining furnace for drying of the raw material and reducing agent or the like. CONSTITUTION:A raw material such as mill scale and a reducing agent such as coke are fed through an inlet 21 into a hot wind generating furnace 2 of a rotary dryer 8, and are discharged through an outlet 22 after drying. A carriage 9 packed therein with these materials is drawn into a tunnel type calcining furnace 1 from the right end and is passed through a preheating zone 10, a calcining zone 11 and a cooling zone 12, whereby sponge iron is obtained. The combustion gas generated with a burner 13 in this stage is discharged with a blower 14. The waste gas thereof or the waste air from the zone 12 in which cooling air 15 is supplied is sucked with a fan 16 and is supplied through a flow rate setter 17 such as a damper into the furnace 2. If the waste gas is excessive, a control mechanism 29 is operated by a flowmeter 19 to control a valve 18 so that the gas is released into the atmosphere. The waste gas introduced into the furnace 2 is mixed with the combustion gas of a burner 7 and the temp. thereof is detected with a therometer 3. The combustion of the burner 7 is controlled by an arithmetic part 6.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a manufacturing method using the sponge method, and more specifically, raw materials such as mill scale and redundant agents such as coke are dried by a drying mechanism and then filled into a reduction container and then processed into a tunnel-type firing furnace. A method of manufacturing a sponge by passing the sponge through a preheating zone, a firing zone and a cooling zone.

Raw materials such as mill scale that have been subjected to a specified drying process by a drying mechanism and a reducing agent such as coke are filled into an appropriate reduction container and passed through a pre-heating zone, a firing zone, and a cooling zone of a tunnel-type firing furnace. In the previous method of manufacturing sponge method, the cooling air blown into the cooling zone of the firing furnace absorbs heat from the fired product, reaching a high temperature of about 4'00-50σG, but it is released directly into the atmosphere. The combustion gas generated by the burner, which is also installed in a certain station, burns the raw materials and is then led to the preheating zone. However, Nao 4
00-50 (fc) It is customary to release the considerable sensible heat remaining in the cooling air and the exhaust gas into the atmosphere in vain.

Although it is also possible to introduce high-temperature cooling air from the cooling zone of the kiln or flue gas from the preheating zone to a heat exchanger and use it to preheat the air,
i 16 hours and requires considerable maintenance costs.

The present invention aims to solve this problem of heat loss occurring in previous methods of producing sponge iron.

The purpose of the present invention is to improve thermal efficiency by utilizing the sensible heat remaining in the air or exhaust gas discharged from the cooling zone or preheating zone of a tunnel type kiln in a shell, such as by using dry VC for raw materials or reducing agents. The objective is to find a method for producing sponge iron that is useful for humans.

According to the present invention, a raw material such as mill scale and a reducing agent such as coke are dried by a drying mechanism and then filled into a reducing container. A method for producing sponge iron, the cooling air being introduced into the cooling zone of a firing furnace and absorbing heat from the fired product, or the combustion gas generated in the firing zone, being extracted. A method for producing sponge iron is obtained, which is characterized in that the sponge iron is supplied to a drying mechanism.

An embodiment of the method of the present invention will now be described with reference to the accompanying drawings.

Referring to FIG. 1, a conventional drying process is shown in which a can body 8 is used to pre-treat a raw material such as mill school and a reducing agent such as coke. The drying process is carried out using an elongated can body 8 called a rotary dryer. The can body 8 is provided with an intake port 21 for the raw material W at the left end, and an outlet 22 for the dried raw material W is attached to the center right side.

A hot air generating furnace 2 is provided inside the right end of the can body 8, and a burner 7 attached to the outside of the right end of the hot air generating furnace 2 opens into the hot air generating furnace 2. Burner 7 Vc is fuel supply pipe 2
4 and the air supply 4'F"l" 25 are connected.

The fuel supply pipe 24 and the air supply pipe 25 are each electrically connected to the calculation section 6, respectively. A thermometer 3 inserted into the upper center of the outlet chamber 27' is connected to a calculation unit 6, and the calculation unit 6 controls a fuel controller 4 and an air controller so that the thermometer 3 always indicates a predetermined temperature. Issue commands to 5. A dust remover 20 and a suction fan 23 are installed at the left end of the can body 8 via an inlet chamber/bar 27.
are connected. Water is similarly removed from raw materials such as mill scale and reducing agents such as coke by this drying mechanism.

FIG. 2 shows a conventional tunnel-type kiln 1, with a preheating zone 10. A firing zone 11 is provided at the center, and a cooling zone 12 is provided at a portion adjacent to the 9 ends. A cart 9 loaded with a large number of containers (shown in the diagram -U''') filled with the C material W processed by the drying mechanism shown in FIG. The inside of the furnace C/ζ user 2], :'-) is configured to be brought out of the furnace from the left end after passing through a pre-heating zone of 10 degrees, a firing zone 11, and a cooling zone 12.The upper part of the firing zone 11 Burner 1 in Furnace 1
3 is installed. Burner 1: Also firing zone 1
The combustion gas generated in step 1 burns the raw material and then preheats the VC raw material W together with the guide, truck, and container, and then is discharged to the outside of the furnace by the discharge blower 14.

As mentioned above, the exhaust gas discharged from the preheating zone 10 is 400
-500°C9) High temperature and still retains considerable sensible heat. Cooling air 15 is supplied by a blower 26 to the cooling 4j\12 at the left end of the firing furnace 11. An exhaust fan 16 is provided to discharge the cooling air 15, which has absorbed heat from the cart, container, and fired product and has reached a high temperature of about 100-500° C., out of the furnace.

As mentioned above, the cooling air released into the atmosphere in this manner also contains a considerable amount of sensible heat.

No. 3N9 shows the apparatus used in the method of the present invention,
The drying mechanism is the same as the drying mechanism shown in FIG. 1, and the firing furnace is the same as the firing furnace 1 shown in FIG.

A duct 28 has one end opened to the cooling zone 12 of the firing furnace 1, and the other end opens to the hot air generating furnace 2 of the rotary dryer. The duct 28 is equipped with a flow position setting device 17 such as a dam bar at a position adjacent to the hot air generating furnace 2, and the firing furnace 1
The above-mentioned exhaust fan 16 is installed at a position adjacent to the exhaust fan 16. The flow meter 19 attached to the duct 28 I/C at the suction 9111 of the exhaust fan 16 is connected to the control mechanism 29 of the control valve 18 provided on the discharge side of the exhaust fan 16. When the air flow from the cooling zone 12 of the firing furnace 1 becomes excessive, it is controlled by releasing it to the atmosphere. In this way, the cooling air 15 with a temperature of 400-500°C discharged from the cooling zone 12 of the firing furnace 1 is directly supplied to the hot air generating furnace 2 of the rotary dryer, and the retained sensible heat is directly transferred to the rotary dryer. Supply to dryer.

Although not shown, the combustion exhaust gas drawn out from the preheating zone 10 by the exhaust blower 14 shown at the right end of the firing furnace 1 is also supplied to the generating furnace 2 as heat from the drying mechanism 80 using a duct in exactly the same manner. Can be done.

In the hot air generating furnace 2ζJ, the cooling zone exhaust gas introduced into the furnace and the combustion gas generated by the burner 7 become a mixed gas, and the temperature of the mixture is detected by the thermometer 3 and transmitted to the calculation unit 6, and the temperature of the mixed gas is determined. Fuel open side) device 4 to maintain the set value
．． Combustion in the burner 7 is controlled by a combustion air controller 5. The raw material W is dried in the can body 8 by a mixed gas tray.

The mixing vessel used for drying passes through the ζ-chamber 27 and the dust remover 2o, and is discharged into the atmosphere by the exhaust blower 23.

Example 1, using a drying mechanism (rotary dryer), rate 3
%, amount of coke gas blown into burner 7 631 (ms
A. The amount of combustion air blown (at room temperature) was 340 Nrn5/9, but the combustion air was discharged from the cooling zone of the kiln.
By using 0C high temperature exhaust with 8001" 1tns flea, the coke gas injection amount was set to 38 Nrn34.
5 Nms term 'Fuel savings could be achieved.

As described above, according to the present invention, the exhaust gas from the kiln furnace cooling zone is used as it is as an auxiliary heat source for drying raw materials, so fuel consumption can be significantly reduced without investing in the cost of equipment such as a heat exchanger, contributing to energy conservation. Stand-C thing h? -I can.

Example 2 Coke treatment B, 1.5TA using a drying mechanism.

Coke moisture content 14.5%, coke gas injection amount to burner 7 52Nm3/i-(, combustion air injection amount 28O
/J1, which was operating at Nm s, /H, corrected the coke gas injection and reduced only the 400C cooling zone exhaust to 20C.
By blowing at a rate of 0 ON m s, /H, coke can be satisfactorily dried without using any particular fuel, resulting in significant energy savings.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a conventional four-component drying mechanism, FIG. 2 is a schematic diagram showing a conventional tunnel type kiln, and FIG. 3 is a schematic diagram showing an apparatus used in the method of the present invention. 1 Tunnel-type firing furnace 3 Temperature side 4 Fuel controller 7 Burner 10 Pre-heating zone 11
・Output 12 Cooling zone 13 Burner 14 Pyoar 15 Cooling air 16 Fan 17 Meteor setting device 18 Control valve 19 Flow repair meter 20 Dust remover 21 Raw material intake 22 Raw material outlet 23 Exhaust fan 28 Duct 29 Control mechanism

Claims (1)

[Claims] In this method, raw materials such as mill scale and reducing agents such as coke are dried using a drying mechanism, and then filled into a reduction container and passed through a preheating zone, a firing zone, and a cooling zone of a tunnel type kiln. The sponge is characterized in that cooling air introduced into the cooling zone of the firing furnace and absorbing heat from the fired product or exhaust gas of combustion gas generated in the firing zone is extracted and supplied to the drying mechanism. Method of manufacturing law.