JP5462503B2 - Recycling method of tar sludge discharged from coke oven - Google Patents

Description

  The present invention relates to a method for recycling tar sludge discharged as a by-product from a coke oven in an iron making process.

  In the coke oven of the steelmaking process, the exhaust gas from the coke oven is refined by a gas refining facility and used as an energy source in the steelworks. When cooling the exhaust gas from the coke oven in this gas refining facility, a large amount of solid-liquid mixture is used. Will occur.

  This solid-liquid mixture is statically separated into sludge containing water, tar, and tar (tar sludge) in a decanter. Among these, the liquid tar content is centrifuged as shown in Patent Document 1, for example. It has been proposed to improve the coke productivity by making it adhere to the raw coal and sending it to the coking chamber of the coke oven. However, grease-like tar sludge with high viscosity and poor fluidity has not been used effectively so far, and although some of it has been returned to the coke oven, it has been exclusively incinerated and from the viewpoint of effective use of resources. It was a problem.

JP 2005-272715 A

  Therefore, the object of the present invention is to solve the above-mentioned conventional problems, and to recycle tar sludge discharged from a coke oven that can recycle tar sludge that has been mainly incinerated in the past as valuable resources. Is to provide a method.

The present invention made to solve the above-mentioned problems is after the solid-liquid mixture obtained by cooling the exhaust gas of the coke oven is statically separated with a decanter and the moisture content is adjusted to 8 to 10% by mass. The tar sludge is taken out and transferred to a vibration mill having a large number of vibration rods inside a cylinder via a receiving pit having a heat retaining and stirring function, and the sludge is particle size 100 μm by the vibrating rod. It is finely pulverized so that the following cumulative ratio is 90% or more, and the viscosity in the range of 50 to 70 ° C. is adjusted to 200 to 1000 mm ² / s, and used as a granulating binder for activated carbon production. Recycled tar sludge is used.

In addition, it is preferable to store the obtained reproduction | regeneration tar sludge in the storage tank provided with the heat retention and stirring function, and to ship to a user.

Moreover, it is preferable that the heat retention conditions of tar sludge and recycled tar sludge be 40 to 60 ° C.

According to the present invention, tar sludge, which has been difficult to use effectively due to its high viscosity and poor fluidity, is finely pulverized by a vibrating rod of a vibrating mill having a large number of vibrating rods inside a cylinder. In addition, the viscosity in the range of 50 to 70 ° C. is adjusted to 200 to 1000 mm ² / s .

And the regenerated tar sludge obtained by finely pulverizing so that the cumulative ratio with a particle size of 100 μm or less becomes a particle size distribution of 90% or more is used as a granulating binder for producing activated carbon .

It is a block diagram which shows embodiment of this invention. It is a front view of a vibration mill. It is a top view of a vibration mill. It is sectional drawing of a vibration mill.

Embodiments of the present invention will be described below.
1 is an exhaust gas purification device for a coke oven similar to the conventional one. In the exhaust gas purification device 1, a solid-liquid mixture such as water, tar and sludge is generated by cooling the exhaust gas. This solid-liquid mixture is taken out into the decanter 2 and allowed to stand and be separated.

  When static separation of the solid-liquid mixture is performed with the decanter 2, the upper layer is separated into a low-viscosity liquid layer (moisture part), a high-viscosity liquid layer (tar part), and a solid residue-based tar residue layer (tar sludge). The In addition, the emulsion part which is a mixed layer exists between a moisture part and a tar part. Tar sludge is a substance in which tar adheres to sandy sludge, and as described above, it has high viscosity and poor fluidity as it is.

  In this invention, this tar sludge is taken out to the receiving tank 3 in the state which adjusted the water | moisture content. A preferable moisture content is 5 to 15% by mass. If the amount of water is outside this range, it is not preferable for use as fuel or the like, and therefore, excess water is separated and removed. A more preferable water content is 8 to 10%. The receiving tank 3 is a tank having a heat retaining and stirring function, and stirs the tar sludge at a speed of about 30 to 50 rpm with, for example, a paddle type stirrer while keeping the temperature at 40 to 60 ° C. Thereby, precipitation and solidification of tar sludge are suppressed, and suction and conveyance by a sludge pump are enabled. The conditions for heat retention and stirring are the same in the following steps. However, if the equipment is not located on the same site and is transported by a tank lorry, the heat retention and stirring can be omitted if the traveling time is short.

  Next, the tar sludge is transferred to the vibration mill 5 via the receiving pit 4. The receiving pit 4 is a facility for receiving the tar sludge transferred from the receiving tank 3, and is a tank having the same heat retaining and stirring functions as described above. In this embodiment, since the exhaust gas purifying apparatus 1 and the vibration mill 5 are not adjacent to each other, such a configuration is adopted. However, if both are adjacent, the receiving tank 3 and the receiving pit 4 are shared. You can also.

  The vibration mill 5 is equipment for finely pulverizing tar sludge with a vibrating rod. An example thereof is as shown in FIGS. 2 to 4, and a cylindrical mill body 20 in which a large number of rods 21 are housed is vibrated by a vibration shaft 23 driven by a motor 22. In this embodiment, the mill main body 20 has two upper and lower stages, and tar sludge is introduced from the inlet 24 located at the front end of the upper mill main body 20 and flows into the lower mill main body 20 at the rear end. It is discharged from a discharge port 25 located at the front end of the mill body 20.

  The upper and lower two-stage mill main body 20 is supported at two places on the front and rear by a support frame 27 supported by a spring 26. Then, the mill main body 20 is vibrated vigorously by bringing the bearing portions 28 of the two vibration shafts 23 disposed on both sides thereof into contact with the support frames 27. The amplitude is 8 mm, for example, and the frequency is 1200 times per minute. The rod 21 is made of steel and contains hundreds of rods with a diameter of 25 mm and a length of 3 m. Tar sludge exerts an impact force between the rods 21 that vibrate while flowing inside the mill body 20. The solid content is received and pulverized.

Since such fine pulverization proceeds and the viscosity of the tar sludge also decreases, the vibration mill 5 is operated so that the viscosity in the range of 50 to 70 ° C. falls within the range of 200 to 1000 mm ² / s. Thus, the major feature of the present invention is that the decrease in the viscosity proceeds as the solids are finely pulverized. Note in the range of viscosities of 200 to 1000 mm ² / s, this becomes costly and not easy to reduce the viscosity than the viscosity conversely becomes difficult to use as a fuel exceeds 1000 mm ² / s It is.

  The degree of pulverization depends on the application, but when used as an alternative to heavy oil, it may be pulverized so that the particle size of the sludge is 250 μm or less. However, when used as a granulating binder for the production of activated carbon, by changing the operating conditions of the vibration mill 5 or performing pulverization a plurality of times, the cumulative ratio of particle size of 100 μm or less becomes a particle size distribution of 90% or more. It is preferable to finely pulverize. In this way, the tar sludge is regenerated sludge whose solid content is pulverized and reduced in viscosity by being processed by the vibration mill 5, and is thus stored in the storage tank 7 via the payout pit 6 and received by the user. Ship to tank 8. The payout pit 6, the storage tank 7, and the user's receiving tanks 8, 9, and 10 are all tanks having the above-described heat retaining and stirring functions.

  The user provided with the receiving tank 8 is a factory that uses, for example, regenerated tar sludge as fuel for a quick kiln rotary kiln. In this factory, C heavy oil was conventionally used as the fuel for the rotary kiln, but the regenerated tar sludge obtained by the present invention can be equivalent to C heavy oil in both viscosity and calorific value, and can be used as an alternative fuel. .

  The user having the receiving tank 9 is, for example, a factory that uses recycled tar sludge as fuel for an aluminum scrap melting furnace. In this factory, A heavy oil was conventionally used as the fuel for the aluminum scrap melting furnace, but the recycled tar sludge obtained by the present invention can adjust the viscosity and the calorific value to the equivalent of A heavy oil, so as an alternative fuel It can be used. For adjustment, a high-viscosity waste oil or a low-viscosity waste oil may be used, and the mixing amount may be adjusted so as to obtain an appropriate viscosity.

The user having the receiving tank 10 is a factory that uses, for example, recycled tar sludge as a granulating binder for producing activated carbon. In this case, a regenerated tar sludge in which the solid content is finely divided so that the cumulative ratio of the particle size of 100 μm or less is 90% or more, that is, the cumulative particle size distribution of 90% or more is 100 μm or less is used. If this recycled tar sludge is kneaded with a carbon-based aggregate and fired, the recycled tar sludge is softened and melted at 350 to 500 ° C. and functions as a binder.

In addition, when the distance from the storage tank 7 to a user's receiving tank is separated, the transfer by a tank lorry or the like is necessary. However, when a long time is required, the transfer is preferably performed while keeping warm and stirring.

In a decanter installed in a gas refining facility of a coke oven at an ironworks, the solid-liquid mixture generated by cooling the exhaust gas was left standing and separated, and tar sludge having a water content of 8 to 10% by mass was taken out. When the properties were analyzed, it was found that, in addition to moisture, the oil content was 56.1-58.2 mass%, the solid content was 35.9-36.6 mass%, and the element in the solid content was 60.1-62 C. 0.0% by mass and H was 7.2 to 8.0% by mass.

  The tar sludge is taken out into a receiving tank kept at 40 to 60 ° C., collected with a powerful suction wheel while stirring at a stirring speed of 40 rpm by a paddle type stirrer, and transported to a receiving pit attached to a vibration mill in the steelworks premises. did. This receiving pit is also kept at 40 to 60 ° C. and is equipped with a paddle type stirrer of 40 rpm.

The vibration mill was as described in the embodiment, and the solid content of the tar sludge was finely pulverized and adjusted so that the viscosity in the range of 50 to 70 ° C. was in the range of 200 to 300 mm ² / s. The particle size after pulverization was a maximum of 250 μm. The regenerated tar sludge whose fineness was adjusted while finely pulverizing the solid content in this way was taken out into the discharge pit at the exit of the vibration mill and further stored in the storage tank. These payout pits and storage tanks are also kept at 40 to 60 ° C. and are equipped with a paddle type stirrer of 40 rpm.

By passing the above tar sludge twice through a vibration mill, the regenerated tar sludge finely pulverized so that the cumulative particle size distribution is 90% or more is 100 μm or less is transported to an activated carbon manufacturing plant, and the carbon aggregate is used as a binder. It was confirmed that high-strength activated carbon can be produced by kneading, granulating and firing.

DESCRIPTION OF SYMBOLS 1 Exhaust gas purification apparatus 2 Decanter 3 Receiving tank 4 Receiving pit 5 Vibrating mill 6 Discharging pit 7 Storage tank 8 User receiving tank 9 User receiving tank 10 User receiving tank 20 Mill main body 21 Rod 22 Motor 23 Vibrating shaft 24 Inlet 25 Outlet 26 Spring 27 Support frame 28 Bearing part

Claims (1)

The solid-liquid mixture obtained by cooling the coke oven exhaust gas is left and separated in a decanter , the moisture content is adjusted to 8 to 10% by mass, the tar sludge is taken out, and the tar sludge is kept warm and stirred. It is transferred to a vibration mill having a large number of vibrating rods inside the cylinder via a receiving pit provided with a sludge so that the cumulative proportion of particles having a particle size of 100 μm or less is 90% or more in particle size distribution by the vibrating rods. And the viscosity in the range of 50 to 70 ° C. is adjusted to 200 to 1000 mm ² / s to obtain a recycled tar sludge used as a granulating binder for the production of activated carbon, and discharged from a coke oven To recycle tar sludge.

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