KR20040020380A - Sludge separation method of furnace gas - Google Patents

Abstract

The present invention is to distinguish the reusable sludge and the unusable sludge by the dry, wet, centrifugal dehydration method of the gas generated in the blast furnace to increase the resource recovery rate by reusing the reusable sludge in the blast furnace, the use of sludge The present invention relates to a method for separating zinc-containing sludge from blast furnace gas, which minimizes the occurrence of pollution and prevents environmental pollution. The method includes: a first step of separating gas and sludge from a gas supplied from a blast furnace; A second step of separating the gas and the liquid sludge by receiving the gas generated in the dry processor from the first wet processor; A third step of separating the gas and the liquid sludge by receiving the gas generated in the first wet processor from the second wet processor; A fourth step of separating the large-sized dewatered sludge and the small-sized liquid sludge by inputting the liquid sludge separated by the first wet processor into the first centrifugal dewatering separator; The fifth step of separating the large-sized dewatered sludge and the small particles of liquid sludge by inputting the liquid sludge separated in the first centrifugal dewatering separator to the second centrifugal dewatering separator.

Description

Sludge separation method of furnace gas

The present invention relates to a method for separating zinc-containing sludge of blast furnace gas, and more specifically, to separate the reusable sludge and the sludge which cannot be used by dry, two wet and two centrifugal dehydration methods. Reusable sludges are reused in blast furnaces, and unused sludges are related to a method for separating zinc-containing sludges from blast furnace gas.

Conventional blast furnace zinc-containing sludge separation method is to separate the gas and dry sludge (cake) 70 by receiving the gas generated in the blast furnace (F) from the dry catcher (dust catcher), as shown in FIG. The dry sludge is sent to a treatment plant and the gas is sent to a primary wet processor 20 (venturi scrubber).

As described above, the gas introduced into the first wet processor 20 is sprayed with water from the wet processor 20 and separated into liquid sludge and gas, and the separated liquid sludge is a precipitator 50 (thickener). When the sludge is precipitated and separated into the bottom of the water, the separated sludge is transferred to the drum filter 60 to be dewatered and the dewatered cake 70 is landfilled. And the sludge of the settler 50 is precipitated and the remaining water and the water generated by dewatering the sludge of the drum filter 60 is transferred to the water storage device 40 is stored.

On the other hand, the gas treated and generated in the primary wet processor 20 is supplied to the secondary wet processor 30, where water is injected again, similarly to the primary wet processor 20, and separated into liquid sludge and gas. The separated liquid sludge is provided as water used in the primary wet treatment machine 20. However, the liquid sludge generated in the secondary wet processor 30 may be used as water in the primary wet processor 20 because the amount of sludge is extremely small.

In addition, the water used in the secondary wet processor 30 is the water stored in the water storage device 40 is supplied, the gas generated in the secondary wet processor 30 is a gas holder (not shown) Through the blast furnace (F) is reused.

In the blast furnace zinc-containing sludge separation method treated in the same manner as described above, the sludge generated in the blast furnace and contained in the gas entering the dry processor 10 is all passed through the 1.2 wet filter 20.30 by the drum filter 60. Since it is dehydrated to be generated as the final sludge (cake) 70, the amount is too large, and therefore, the amount of landfill needs to be increased, thereby increasing the environmental pollution.

In addition, the final sludge (cake) 70 dehydrated by the drum filter 60 contains a large amount of Fe (about 37%), and Zn is also contained about 1.17%. By forming the furnace wall attachment, there is a problem in that the load distribution confusion of the blast furnace is caused, as well as the instability of the furnace, thereby degrading the quality of the molten steel. Therefore, in order to use the final sludge (cake) 70 in the blast furnace, a cake having a low Zn content must be separated and used.

The present invention has been invented to solve the above problems in view of the above problems, the object of which is to reuse the gas generated in the blast furnace sludge with a low Zn content by the method of dry, wet, centrifugal dehydration and Zn content not available The present invention provides a method for separating zinc-containing sludge from blast furnace gas, which allows the sludge having a low Zn content to be reused in the blast furnace and allowing the sludge having a high Zn content to be landfilled.

1 is a schematic view for explaining a method for separating zinc-containing sludge of conventional blast furnace gas,

2 is a schematic view for explaining a method for separating zinc-containing sludge of blast furnace gas according to the present invention,

Figure 3 is a partial cutaway perspective view of the extracting device for separating the zinc-containing sludge of blast furnace gas according to the present invention.

※ Explanation of symbols about main part of drawing ※

10: dry processor 20: primary wet processor

30: 2nd wet processor 40: water storage device

50: sedimentation apparatus 80.90: 1.2 centrifugal dewatering separator

81.91: Drum 82.92: Screw Shaft

83.93: Screw 84.94: Hole

F: blast furnace

Looking at the process of the present invention for achieving the above object, the first step of separating the gas and sludge by receiving the gas generated in the blast furnace from a dry processor; A second step of separating the gas and the liquid sludge by receiving the gas generated in the dry processor from the first wet processor; A third step of separating the gas and the liquid sludge by receiving the gas generated in the first wet processor from the second wet processor; A fourth step of separating the large-sized dewatered sludge and the small-sized liquid sludge by inputting the liquid sludge separated by the first wet processor into the first centrifugal dewatering separator; And a fifth step of separating the large-sized dewatered sludge and the small-sized liquid sludge by introducing the liquid sludge separated by the first centrifugal dewatering separator into the second centrifugal dewatering separator.

Hereinafter, a method of distinguishing sludge with a high Zn content and sludge with a low Zn content from the gas generated in the blast furnace will be described with reference to Examples.

First, the sludge contained in the blast furnace exhaust gas is shown in Table 1 below.

Particle size distribution +71 μm 10.6% +36 ㎛ 26.3% + 20㎛ 30.7% -20㎛ 32.4% ingredient T-Fe 37% C 27 Zn 1.17

As shown in Table 1, it can be seen that the particle size distribution of the sludge contained in the blast furnace exhaust gas is different. On the other hand, the smaller the particles per unit weight of the sludge, the larger the particle size, the larger the surface area. Therefore, the smaller the particle size, the larger the amount of Zn attached, and the larger the particle size, the smaller the amount Zn attached. Therefore, the smaller the particle size, the higher the Zn content. The larger the particle size, the smaller the Zn content. Therefore, the larger the particle size, the lower the content of Zn, so the blast furnace can be reused, and the smaller the particle size, the higher the content of Zn.

As described above, a method of separating sludge having a large particle size that can be reused in a blast furnace and sludge having a small particle size that cannot be reused in a blast furnace will be described in detail with reference to FIGS. 2 and 3.

The gas generated from the blast furnace F is supplied from a dry catcher 10 (dust catcher) to separate the gas and dry sludge (keag), the dry sludge is sent to the treatment plant and the gas is sent to the primary wet processor 20 ( venturi scrubber). As described above, the gas entering the first wet processor 20 is sprayed with water from the wet processor 20 and separated into liquid sludge and gas, and the separated liquid sludge is the first centrifugal dehydration device 80. ) To separate large particles of dewatered sludge and small particles of liquid sludge. On the other hand, the method of injecting the liquid sludge into the primary centrifugal dewatering separator 80 inserts a supply pipe P into the screw shaft 82 by a predetermined amount (near the central part), and then supplies the liquid sludge therethrough. Discharge through the hole (H)

As described above, the liquid sludge supplied to the first centrifugal dewatering separator 80 separates large particles of dewatered sludge and small particles of liquid sludge. 20, the liquid sludge discharged from 20 is supplied into the drum 81 through a screw shaft 82 having a screw 83 installed inside the drum 81, and then the drum 81 and the screw 83 are supplied. When rotated, the large particles of sludge are located in the inner surface of the drum 81, and the small particles are located in the center of the drum.

Therefore, the large particles of sludge located in the inner surface portion of the drum 81 are discharged to the outside by the screw 83, and the sludge of the small particles located in the center of the drum 81 is screwed out. Through the holes 84 formed in the 83, large particles are discharged in the opposite direction from which they are discharged. However, the drum 81 on the side from which the large particles are discharged is gradually narrowed and dehydrated. On the contrary, the sludge discharged is discharged in a liquid state together with water.

At this time, the sludge of the dehydrated and discharged large particles is a Zn-containing content as described above, so that it is a pallet shape to be reused in the blast furnace, and the sludge discharged in the liquid state is a secondary centrifugal dehydration apparatus (90). In the same manner as the primary centrifugal dewatering device 80, and supplied sludge to the inside of the drum 91 through a screw shaft 92 having a screw 93 installed inside the drum 91. Then, when the drum 91 and the screw 93 are rotated, the large particles of sludge are located in the inner surface of the drum 91 and the small particles are located in the center of the drum.

Therefore, the large particles of sludge located in the inner surface portion of the drum 91 are discharged to the outside by the screw 93 in the rotational direction of the screw, and the sludge of the small particles located in the center of the drum 91 is screwed. Through the holes 84 formed in the 93, large particles are discharged in the opposite direction from which they are discharged. However, the drum 91 on the side from which the large particles are discharged is gradually narrowed and dehydrated. On the contrary, the sludge discharged is discharged in a liquid state together with water. The dehydrated sludge is landfilled and vice versa. Is transferred to the water storage device 40 and stored, and is supplied to and used in a secondary wet processor.

The gas treated and generated in the primary wet processor 20 is supplied to the secondary wet processor 30 where water from the water storage device 40 is supplied to be separated into liquid sludge and gas, and the separated Liquid sludge is used as water used in the primary wet treatment machine 20. However, the liquid sludge generated in the secondary wet processor 30 may be used as water in the primary wet processor 20 because the amount of sludge is extremely small. In addition, the gas generated in the secondary wet processor 30 is reused in the blast furnace (F) through a gas holder (not shown).

Hereinafter, an embodiment of a method of distinguishing sludge with high Zn content and sludge with low Zn content in the 1.2th centrifugal dewatering separator (80.90) will be described with reference to FIG. 3. By using the principle that the larger particles are located toward the inner surface of the drum and the smaller particles are located toward the center of the drum, the granularity layer is formed to separate the layers (1/20 of the drum diameter), and the difference between the particle size layer and the sludge discharge height is determined. Let's make about 1/5-1/10.

In low Zn drums, the height difference is about 1/5 of the grain size value, and in high Zn drums, the height difference is about 1/10 of the grain size value. Large differences in discharge heights result in high water content but low recovery rates. In addition, the Zn content of the sludge that can be recycled in the blast furnace should be 0.3% or less.

The Zn content is determined by the G value and the G value is expressed by the following formula.

G = RN ^2/900

Where R is the radius of rotation of the drum

N: RPM of the drum

The Zn content and the recovery rate relative to the G value of the sludge recyclable in the blast furnace are shown in Table 2 below.

Conditions for Drums for Low Zn G value Zn content Recovery rate G ≥990 Zn% ≤0.3% Recovery rate ≥70%

The above table shows the values obtained by experiments. In low Zn drum, the Z value should be more than 990 because the sludge recovered should be less than 0.3%.

Conditions for Drums for High Zn

G value Recovery rate 500 ≥G ≥550 Recovery rate ≥97%

The above table shows the values obtained by the experiment, and the recovery rate of the high Zn drum should be 97% or more, so that it can be used as recycled water of the second wet scrubber 30, and more than 70% of the sludge is recovered at low Zn. Since the sludge concentration is low, the range of G value should be less than 550. However, if the G value is too low, the sludge separation itself does not work. Therefore, the G value should be operated within 500 ≥ G ≥550.

As described above, the present invention separates the blast furnace sludge into high Zn-containing sludge and low Zn-containing sludge, thereby reusing the low Zn-containing sludge to reduce the amount of waste generated and reduce the raw material cost, and a conventional water treatment system such as a thickener. There is no need for easy facility management, and all the treatments are performed in the drum to prevent the occurrence of steam and odor.

Claims (1)

A first step of separating gas and sludge from the gas generated in the blast furnace from a dry processor; A second step of separating the gas and the liquid sludge by receiving the gas generated in the dry processor from the first wet processor; A third step of separating the gas and the liquid sludge by receiving the gas generated in the first wet processor from the second wet processor; A fourth step of separating the large-sized dewatered sludge and the small-sized liquid sludge by inputting the liquid sludge separated by the first wet processor into the first centrifugal dewatering separator; Separating the blast furnace zinc-containing sludge comprising; a fifth step of separating the liquid sludge of the large particles and the liquid sludge of the small particles by inputting the liquid sludge separated by the first centrifugal dewatering separator to the second centrifugal dewatering separator Way.