JP2587750B2 - Dust treatment method for blast furnace dry dust collector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating dust collected by a dry dust collector for a blast furnace.

[0002]

2. Description of the Related Art Conventionally, dust collected by a blast furnace dry dust collector is provided with an intermediate hopper provided with a pressure equalizing valve and an exhaust pressure valve below the hopper of the dust collector as disclosed in Japanese Patent Application Laid-Open No. 59-59234. Was discharged while sealing the blast furnace gas. However, since the intermediate hopper and the shut-off valve for equalizing the pressure above and below it and a rotary valve for cutting out are provided, the height of the entire dust collector is increased, and many movable parts such as valves and rotary valves are provided. Operation and maintenance are also complicated.

Accordingly, the present inventors have developed a dry dust collector for a blast furnace equipped with a dust transport device requiring little maintenance, and disclosed in Japanese Utility Model Laid-Open No. 62-144524.
The improvement measures were introduced in Japanese Utility Model Laid-Open No. 1-174026.
The dust collected by the blast furnace dry dust collector is reused as raw material for cement, etc.
Since the amount of a and K is large and affects the quality of the recycled product, the dust collected by a dry dust collector is washed with water and then dewatered before use.

FIG. 3 shows the configuration of the apparatus. Exhaust gas generated in the blast furnace 1 is conveyed to a plurality of parallel dry dust collectors 3 after dust having a relatively large particle size is removed by a coarse dust collector 2. A dust extraction valve 5 and a dust extraction pipe 6 are provided in a lower hopper 4 of the dry dust collector 3, and the outlet thereof is connected to a dust hopper 8 via a dust transport pipe 7.

[0005] A part of the gas discharged from the dry dust collector 3 through the outlet gas pipe 9 is blown into the dust transport pipe 7 through the pressurizing blower 10 and the carrier gas pipe 11. This gas acts as a carrier gas and is used as a dry dust collector 3
The dust collected in the step is smoothly transported to the dust hopper 8 by airflow.

The dust conveyed to the dust hopper is separated from the carrier gas by a dry dust classifier 12 (eg, a bag filter) provided at an upper portion, and is discharged out of the system by a dust discharge valve 13 provided at a lower portion. You. During discharge, dust is generated. To prevent this, an appropriate amount of water is added by the humidifier 14, and then washing water is supplied at the slurry pit 15 to wash the Cl, Na, and K components in the collected dust. I do. The dust turned into a slurry in the slurry pit 15 is sent to a dewatering device 17 by a slurry pump 16.

On the other hand, the energy of the blast furnace gas cleaned by the dry dust collector is recovered by the turbine 18 and sent to the next step through the clean gas pipe 20. Reference numeral 19 denotes the turbine 1
Reference numeral 21 denotes a furnace top pressure control valve for controlling the furnace top pressure of the blast furnace when the furnace 8 does not operate, and reference numeral 21 denotes a carrier gas flow control valve for controlling the flow rate of the carrier gas.

FIG. 4 shows an example in which a bag filter is used as the dry dust classifier 12, and a heat insulating material 30 for preventing dust from adhering to dew condensation on the hopper portion, a shelving prevention device 22 for a discharge section, and a dust filter. A shutoff valve 23 and the like for preventing gas leakage after the discharge is completed are required.

[0009]

However, the above-mentioned conventional equipment configuration has a problem that dust generation at the time of dust discharge cannot be completely suppressed and a blast furnace gas leak cannot be completely prevented. there were. Further, the equipment configuration is complicated, the equipment cost and the operation cost are high, and there is a problem that there is a rotating equipment for handling dust and the maintenance is troublesome. Therefore, an object of the present invention is to solve the above problems.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a blast furnace in which a gas generated from a blast furnace is dust-removed by a dry dust collector and then the energy of the generated gas is recovered by a turbine. A method for treating dust collected by a dry dust collector in a gas energy recovery device, wherein a lower hopper of the dry dust collector is connected to a clean gas pipe on a turbine outlet side by an air flow transport pipe, and a wet type A dust treatment method for a blast furnace dry dust collector, comprising: installing a dust classifier of the type, separating dry dust from an air stream by the wet dust classifier, washing the dust, and discharging the dust outside the system. It is.

[0011]

The dust collected by the dry dust collector is pneumatically transported together with part of the blast furnace gas in the pneumatic transport pipe due to the difference between the pressure in the dry dust collector and the pressure in the turbine outlet pipe. By installing a wet dust classifier in the middle of the airflow pipe, the dry dust is separated from the airflow and washed to be a slurry, which is discharged out of the system. Since the slurry is discharged while being stored in the discharge section, the gas in the dust classifier is sealed with water, and discharged without any dust generation or gas leakage.

[0012]

FIG. 1 is a view showing an embodiment of the present invention, which is an example in which the above-described apparatus of FIG. 3 is improved to carry out the present invention. In FIG. 1, the lower hopper 4 of the dry dust collector 3 and the outlet clean gas pipe 20 of the turbine 18 are connected by a dust transport pipe 7, and a wet dust composed of a gas-liquid contact device 25 and a gas-liquid separation device 26 A classifier is provided. FIG. 2 is a diagram showing details of a wet dust classifier, and is a gas-liquid contact device 25.
Is provided with a washing nozzle 24, and a water supply pipe is provided.

When the dust extraction valve 5 is opened, the dust in the dust collector passes through the gas flow pipe 7 due to the difference between the pressure in the lower hopper 4 of the dry dust collector 3 and the pressure in the clean gas pipe 20 on the outlet side of the turbine 18. The gas is transported to the contact device 25 by air flow, and the Cl, Na, and K components are washed by the washing water sprayed from the washing nozzle 24 by the gas-liquid contact device, and the dust is transferred to the washing water. The cleaning water containing the dust is separated from the gas stream by a gas-liquid separator 26 at the subsequent stage, discharged out of the system as a slurry, and sent to a dehydrator 17 by a slurry pump 16. As shown in the detailed view of the wet dust classifier of FIG. 2, the water level meter 31 and the make-up water flow rate control to keep the level of the lower stored water constant so that the gas inside from the gas-liquid separator 26 does not leak out of the system. A valve 27 is provided.

In FIG. 1, reference numeral 10 designates a portion of the gas discharged from the dry dust collector 3 through the outlet gas pipe 9 as a carrier gas through a carrier gas pipe 11 in order to smoothly carry the air stream of the dust. The booster blower is fed into the dust transport pipe 7, but can be omitted together with the carrier gas pipe 11 when the distance between the dry dust collector 3 and the wet dust classifier is short or when the pressure inside the dry dust collector is high.

[0015]

As described above, the present invention has a simple structure in which the hopper of the dry dust collector is connected to the clean gas pipe on the turbine outlet side by the pneumatic transport pipe, and a wet dust classifier is installed in the middle of the pipe. Accordingly, the dust collected by the dry dust collector can be washed to remove harmful components, and can be discharged out of the system without any dust generation and blast furnace gas leak. Further, since the apparatus configuration is simple, equipment costs and operation costs are reduced, and there is no rotating equipment for handling dust, so that almost no maintenance is required.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing details of a wet dust classifier in FIG. 1;

FIG. 3 is a system diagram showing a conventional example.

FIG. 4 is a diagram showing details in the vicinity of a bag filter in FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Blast furnace 2 Rough dust collector 3 Dry dust collector 4 Lower hopper 7 Dust transport pipe 10 Booster blower 18 Turbine 20 Clean gas pipe 24 Washing nozzle 25 Gas-liquid contact device 26 Gas-liquid separation device 27 Supply water flow control valve

Continuing on the front page (72) Inventor Yuji Kitamura 46-59 Ohara Nakahara, Tobata-ku, Kitakyushu-shi, Fukuoka Nippon Steel Plant Design Co., Ltd. (72) Inventor Masahiko Hamada 5-3 Tokai-cho, Tokai City, Aichi Prefecture Nippon Steel Corporation (72) Inventor Yasuhiko Omatsu 20-1 Shintomi, Futtsu City, Chiba Prefecture Nippon Steel Corporation Technology Development Division (56) References JP-A-3-294714 (JP, A) JP-A Sho 59-41408 (JP, A)

Claims (1)

(57) [Claims] 1. A method for treating dust collected by a dry dust collecting apparatus in a blast furnace gas energy collecting apparatus for removing the gas generated from a blast furnace by a dry dust collecting apparatus and then recovering the energy of the generated gas by a turbine. The lower hopper of the dry dust collector and the clean gas pipe on the turbine exit side are connected by a pneumatic transport pipe, and a wet dust classifier is installed in the middle of the pipe, and the dry dust classifier is used for the dry dust classifier. A dust treatment method for a blast-furnace dry dust collector, wherein the dust is separated from an airflow, and the dust is washed and discharged as a slurry outside the system.