JPS60232229A - Bad smell and oil removing apparatus in purification apparatus of exhaust gas from arc furnace equipped with scrap preheater - Google Patents

Abstract

PURPOSE:To effectively remove the bad smell and the oil component in exhaust gas generated by preheating scraps, by providing an apparatus for blowing a malodorous component neutralizing agent at the position in the vicinity of a bag filter and interposing a pre-duster in this side of the bag filter. CONSTITUTION:A part of exhaust gas, which is exhausted from an arc furnace and burnt in a combustion chamber, is guided to a preheater through a bypass duct and scraps are preheated by the combustion heat of said exhaust gas. The exhaust gas containing the malodorous components and oil fume after the preheating of the scraps is sent to a cooling tower 6 from a duct 4. A Ca-compound is sent into a duct 10 from a pipe 24 to be reacted with the malodorous components and guided to a pre-duster 14 whiel oil mist is adhered to a dust collecting plate 18 to be separated along with dust. The exhaust gas is sent to bag filters 22 through ducts 15, 16 while an alkali solution is injected from a pipe 13' to be adhered to the cake layer of the bag filters 22 to adsorb and removing the malodorous substances when the exhaust gas passes through the bag filters 22.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an arc furnace exhaust gas purification device equipped with a scrap preheater, and more specifically, to an arc furnace exhaust gas purification device that utilizes the exhaust gas to remove scrap during the purification process of gas discharged from an arc furnace. The present invention relates to an exhaust gas purification device equipped with a preheater for preheating, and to a device for removing odor and oil generated from the preheater during scrap preheating.

Prior Art In view of the fact that high-temperature gas is generally discharged from an arc furnace, attempts have been made to provide a preheater during the purification process of the exhaust gas and preheat the scrap using the exhaust gas in the preheater. However, scrap usually has paint or oil on it, or has rubber, rubber, etc.
In many cases, combustible materials (organic or inorganic) such as plastics are mixed in, and these deposits or combustible materials generate bad odors and cause air pollution due to oil being discharged into the atmosphere. -2= In addition to this, the exhaust gas purification function may not be sufficiently effective due to the fact that the same song adheres in the form of tar to moving parts such as the switching damper of the back house, causing malfunction. This method has problems in that it reduces the problem of the bag filter not being able to function properly, and also that it can cause problems such as fires caused by oil adhering to the bag filter.

Purpose of the Invention The present invention is an attempt to improve the conventional situation as described above, and the purpose of the present invention is to effectively remove malodorous components and oil components generated by scrap preheating from exhaust gas. An object of the present invention is to provide a device for removing bad odor and oil that can remove odor and oil.

Structure of the Invention That is, the present invention sprays a neutralizing agent for malodorous components onto a bag filter, and when the exhaust gas passes through the bag filter, the malodorous components in the exhaust gas are reacted with the neutralizing agent. Its features are that it adsorbs and deodorizes the exhaust gas, and by installing a pre-duster in front of the bag filter, oil is removed from the exhaust gas before the exhaust gas is sent to the bag filter 3-. The gist of the present invention is to provide an exhaust gas purification device equipped with a scrap preheater, which is equipped with a blowing device for a malodorous component neutralizer, and to provide a supply pipe extending from the blowing device to the tip of the supply pipe. facing into the main duct,
The tip of the bag filter is installed at a position as close as possible to the bag filter so that the neutralizing agent can be attached to the bag filter, while the main duct has a bag filter attached to the bag filter.
The reason is that the structure is such that the pre-duster is placed in front of the

EXAMPLES Specific examples of the present invention will be described below with reference to illustrative drawings. In the drawing, 1 is an arc furnace, 2 is a combustion chamber, and the arc furnace 1 and the combustion chamber 2 are connected by a duct 3. Two ducts 4.5 are branched and extended from the combustion chamber 2, one of which is connected to the cooling tower 6, and
The other duct 5 is connected to a preheater 7 (scrap preheating device). Reference numeral 8 denotes a duct extending from the preheater 7, and the duct 8 is provided with a booster 9 located at an arbitrary intermediate portion thereof, the tip of which is connected to the duct 4. Each duct 4.5.8 has a damper 4', 5'
, 8' are provided, and each damper 4', 5'', 8'
By adjusting the opening degree of the ducts 4.5, the amount of exhaust gas to be sent to both ducts 4.5 can be arbitrarily selected.

14 is a pre-duster, 11 is a blower, and 12 is a baghouse. The cooling tower 6 and the pre-duster 4 are connected by a duct 10, and the pre-duster 14 and the blower 11 are connected by a duct 15.

The blower 11 and the baghouse 12 are connected by a duct 16. The pre-duster 14 has an appropriate number of dust collecting plates 18 arranged in steps in the front and back direction with appropriate intervals between them, and the plate 18 can be struck at the rear of each dust collecting plate 18. A hammering mechanism 19 is provided as shown in FIG. 5- The pre-duster 14 is provided with a hopper 20 located below the dust collecting plates 1 to 18, and the hopper 20 stores oil-absorbing dust.

Further, the bag house 12 has a hopper 21 at its lower end, and a plurality of bag filters (three cloths) 22 are installed therein. A shaker mechanism 23 is also provided in the bag house 12 above the bag filter 22. The shaker mechanism 23 includes a motor (M) and a cam mechanism (not shown)
It is provided so that vibration can be applied to each bag filter 22 through the drive of the motor (M) and the eccentric rotation of the cam.

Reference numeral 17 denotes a tank for storing Ca compounds such as reduced slag powder, quicklime, fluorite, etc., and a quantitative feedout [1117' is provided at the bottom of the tank 17. Reference numeral 24 denotes a supply pipe for the Ca compound, which is provided in correspondence with the quantitative delivery port 17', and the tip of the pipe 24 is provided so as to face into the duct IO. Reference numeral 13 denotes a tank for storing an alkaline solution (a malodorous component neutralizer), and a supply pipe 13' extends from the tank 13 with a pump (P) attached thereto. is provided facing into the duct 16.

More specifically, a spray nozzle is attached to the tip of the pipe 13', and the nozzle is attached to the baghouse 1.
Can be installed facing in two directions. In addition to alkaline solutions, Ca compounds such as CaO powder can be used as neutralizers for malodor components, but liquids such as alkaline solutions are more effective than powders. By applying appropriate moisture to the bag filter 22, its reaction and adsorption effects can be further enhanced.

Next, its effect will be explained.

The gas discharged from the arc furnace 1 is sent into the combustion chamber 2 through a duct 3 while retaining high-temperature combustion heat (approximately 1,000°C). The exhaust gas thus sent into the combustion chamber 2 has the effect of completely burning the Go gas contained therein. A part of the exhaust gas sent out from the combustion chamber 2 is sent directly into the cooling tower 6 through the duct 7-4, while the other exhaust gas is sent through the duct 5 to the preheater 7, where it is heated. The combustion heat has the effect of preheating the scrap, but the scrap fed into the preheater 7 usually contains paint, oil, rubber, plastic, etc., and these are heated. As a result, malodorous components (for example, compounds such as H2S) are generated, and the oil evaporates to form a hume state (oil hume).

The exhaust gas obtained by preheating the scrap is sent to the cooling tower 6 through the duct 8 and duct 4 in a state where the above-mentioned malodorous components and oil fume are mixed, and a cooling effect is obtained while passing through the inside of the cooling tower 6. (Accordingly, the oil also becomes a mist state (oil mist) rather than a fume state.) The exhaust gas that has obtained a cooling effect is sent into the duct 10, and is sent inside the duct 10 toward the pre-duster 14. Storage tank 1 for the same duct 10
By sending the C8-a compound from 7 through the pipe 24, the malodorous components and Ca in the exhaust gas are removed while the exhaust gas is sent through the duct 10.
The action of the compound reacting, that is, the deodorizing action is obtained. The exhaust residue that has been deodorized in this way is sent into the pre-duster 14.
The exhaust gas sent into the exhaust gas collides with the dust collecting plate 18, and the impact serves to separate oil mist mixed into the exhaust gas. The oil separated from the exhaust gas adheres to the dust collection plate 18, and the hammering mechanism 19
It is shaken off together with dust through the hopper 20 and stored in the hopper 20. Further, the dust (mainly lime) that has absorbed oil in this way is put into the arc furnace 1 and reused as a slag-forming agent, and the oil content becomes the heat of dissolving the scrap.

The exhaust gas from which the oil mist has been separated in the pre-duster 14 is sent into the baghouse 12 via the duct 15, the blower 11, and the duct 16, while the alkaline solution stored in the tank 13 is sent to the pipe 13 via the pump (P). ' and is injected into the duct 16. And in this way the duct 16
The alkaline solution injected into the baghouse 12 is sent into the baghouse 12 along with the exhaust gas through the duct 16, and adheres to the peripheral wall surface of the baghouse 22, that is, the cake layer.

However, when the alkaline solution adheres to the cake layer of the bag filter 22 for leverage, the exhaust gas sent into the baghouse 12 passes through the bag filter 22 and contains malodorous components that remain in the exhaust gas. reacts with the alkaline solution, producing the effect of adsorbing the same malodorous components. (
For example, H2S+ 2 Na OH-) Na 2S
+ 2 H20) Also, when oil mist remains in the exhaust gas, since the oil mist cannot pass through the bug, it has the effect of being separated from the exhaust gas and adhering to the bug.

Effects of the Invention The present invention is constructed as described above, and by providing the pre-duster in front of the bag filter as described above, the exhaust gas is filtered before being sent to the bag filter. It has now become possible to remove the oil mist that gets mixed into the exhaust gas. By being able to remove the oil mist in this way, it is possible to prevent the conventional oil mist from adhering to movable parts such as the switching damper in a tar state, making it impossible for the bag filter to function effectively. We have now been able to eliminate problems and fires caused by oil adhesion to bag filters in advance.

Furthermore, in the present invention, a device for blowing a malodorous component neutralizer is provided, and the tip of a pipe extending from the device is made to face inside the duct, so that the neutralizer sprayed from the pipe can be sprayed into a bug. By making it possible to attach it to the cake layer of the filter, the neutralizing agent can effectively adsorb malodorous components in the exhaust gas when it passes through the bag filter. It's arrived.

That is, according to the present invention, it has become possible to effectively remove malodorous components and oil mist from exhaust gas.

[Brief explanation of the drawing]

FIG. 1 is a flow sheet showing a malodor and oil mist removal device according to the present invention, and FIG. 2 is a schematic side sectional view of the same. 1 arc furnace, 2 combustion chambers, 3.4.5.8.1.0°15
．． 16 ducts, 4', 5', 8' dampers, 6 cooling towers, 7 preheaters, 9 boosters, 11 blowers, 12
Baghouse, 13 Storage tank, 13' Supply pipe, 14
Pre-duster, 17 storage tank, 17' quantitative delivery port, 1
8 dust collection plate, 19 hammering mechanism, 20.21 hopper, 2
2 bag filters - 123 car mechanisms, 24 supply pipes. Patent applicant: Daido Steel Co., Ltd.

Claims (1)

[Claims] (1) A combustion chamber, cooling tower, bag filter, etc. are installed along the main duct extending from the arc furnace, and a scrap preheater is installed along the bypass duct installed between the combustion chamber and the cooling tower. In the exhaust gas purification device installed, a blowing device for a malodorous component neutralizer is installed,
The tip of the pipe extending from the blowing device faces into the main duct, and the tip is positioned close to the bag filter so that the neutralizing agent can be attached to the bag filter. A device for removing odor and oil in an arc furnace exhaust gas purification device, which is equipped with a scrap preheater located in front of a bag filter and having a preduster interposed in the main duct. 1-