KR102246862B1 - Device for purification of coke oven gas and method for purification of coke oven gas using the same - Google Patents

Abstract

The present invention is an absorption tower in which the _{H 2 S absorption liquid absorbs H 2} S from the coke oven gas; A regeneration tower connected to the absorption tower _{to remove H 2 S from the H 2} S absorption liquid; And it provides a coke oven gas purification apparatus including a filter for removing naphthalene contained in _{the H 2} S absorption liquid discharged from the absorption tower, and a coke oven gas purification method using the same. According to the present invention, _{naphthalene is removed from the H 2} S absorbent liquid through the filter to prevent clogging of the heat exchanger and the H _{2 S absorbent liquid tank.}

Description

A coke oven gas purification apparatus and a coke oven gas purification method using the same TECHNICAL FIELD

The present invention relates to a coke oven gas purification apparatus and a coke oven gas purification method using the same.

During the drying process to produce coke, coke oven gas (COG) is generated. This coke oven gas is the main by-product gas of the steel making process used for power generation or fuel in the steel mill. When the coke oven gas is generated from the coke oven _{, it contains impurities such as H 2} S, NH ₃ , BTX (benzene, toluene, mixed xylene), tar, and naphthalene. The process is essential.

Among them, tar and naphthalene must be removed through a cooling process and electrostatic precipitating before the _{H 2 S purification process.} However, depending on the type of coal that is a raw material for coke, coke oven gas containing a large amount of naphthalene may be generated, or naphthalene may not be sufficiently removed through a cooling process and electric dust collection due to insufficient cooling capacity in summer. In this case, the H ₂ S purification process, which is a later process, is affected.

In particular, in the case of a conventional coke oven gas purification device without introducing a separate naphthalene removal device as shown in FIG. 1, naphthalene not only causes clogging of the heat exchanger, but also precipitates in the lower portion of the _{H 2 S absorbent tank 204 and discharges.} It exists in a state that is difficult to process.

Korean Patent Publication No. 10-2013-0070869

An object of the present invention is to remove naphthalene contained in the coke oven gas, thereby preventing naphthalene from causing clogging of the heat exchanger or from sedimentation of naphthalene in the lower portion of the _{H 2 S absorption liquid tank.}

According to an aspect of the present invention, the H _{2 S absorption liquid absorbs H 2} S from the coke oven gas absorption tower; A regeneration tower connected to the absorption tower _{to remove H 2 S from the H 2} S absorption liquid; And a filter for removing naphthalene contained in _{the H 2} S absorption liquid discharged from the absorption tower.

According to another aspect of the present invention, the H ₂ S absorption liquid absorbing H ₂ S from the coke oven gas in the absorption tower; Removing naphthalene from _{the H 2} S absorption liquid using a filter; And there is provided a coke oven gas purification method comprising the step of removing _{H 2 S from the H 2} S absorption liquid in the regeneration tower.

According to the invention, H ₂ S problem absorbing solution is naphthalene is removed by having passed through the pre-filter is stored in the H ₂ S absorbed solution, the build-up leads to naphthalene this heat exchanger clogging, or naphthalene is precipitated in H ₂ S absorption liquid tank bottom Can be solved.

In addition, since the filter can be regenerated through periodic backwashing, the filter can be used for a long time.

1 schematically shows a conventional coke oven gas purification apparatus.
Figure 2 schematically shows a coke oven gas purification apparatus according to an embodiment of the present invention.
3 shows the size distribution of naphthalene particles present in the _{H 2} S absorption liquid after passing through the filter according to an embodiment of the present invention. Dv stands for percentile.
4 shows the size distribution of naphthalene particles present in _{the H 2} S absorption liquid of a conventional coke oven gas purification apparatus. Dv stands for percentile.

Hereinafter, preferred embodiments of the present invention will be described. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

The present invention removes naphthalene contained in the coke oven gas, and purifies the coke oven gas _{to prevent clogging of the absorption tower, heat exchanger, and H 2} S absorption liquid tank (hereinafter also referred to as the absorption liquid tank) of the coke oven gas purification apparatus. It relates to an apparatus and a method of purification.

According to an aspect of the present invention, the H _{2 S absorption liquid absorbs H 2} S from the coke oven gas absorption tower 201; A regeneration tower 202 connected to the absorption tower 201 and _{removing H 2 S from the H 2} S absorption liquid; And a coke oven gas purification apparatus including a filter 203 for removing naphthalene contained in _{the H 2} S absorbent liquid discharged from the absorption tower 201 is provided.

In the coke oven gas purification apparatus, _{a coke oven gas 101 including H 2} S and naphthalene is supplied to a lower portion of the absorption tower 201, and an H ₂ S absorption liquid is supplied to the upper portion of the absorption tower 201. In the absorption tower 201, the coke oven gas and the H ₂ S absorbent liquid contact each other, and the H ₂ S _{absorbent liquid absorbs H 2} S, thereby removing _{H 2} S from the coke oven gas.

In the present invention, the H ₂ S absorption liquid is _{not particularly limited as long as it can absorb H 2} S, but preferably an aqueous ammonia solution or an aqueous amine solution may be used.

In the case of the conventional coke oven gas purification apparatus, naphthalene in the coke oven gas not removed in the cooling process and the electrostatic precipitating process is _{physically combined with the H 2} S absorbent and collected in the absorbent liquid tank 204. Since the temperature of the absorbent liquid tank 204 is generally 30 to 50°C, most of the naphthalene exists in a solid state, and settles in the absorbent liquid tank 204 and accumulates under the absorbent liquid tank 204.

However, the coke oven gas purifying apparatus of the present invention _{can remove naphthalene before the H 2} S absorbent liquid is transferred to the absorbent liquid tank 204 by providing the filter 203 before the absorbent liquid tank 204. _{Referring to FIG. 2, the H 2} S absorbent liquid discharged to the lower portion of the absorption tower 201 is stored in the absorbent liquid tank 204 through a filter 203. The naphthalene removal rate through the filter 203 is 98% or more. At this time, the material of the filter 203 is not limited, but it is preferably carbon steel or stainless steel, and the pore diameter is preferably 10 to 500 μm. If the pore diameter is less than 10 μm, the backwash cycle is short and the operation efficiency is low, and if it exceeds 500 μm, the filtering efficiency is low due to the large amount of naphthalene passing through the filter.

_{The H 2} S absorbent liquid that has passed through the filter 203 is supplied to the regeneration tower 202 through the absorbent liquid tank 204. _{Steam 103 is supplied from the lower part of the regeneration tower 202, and the H 2} S absorption liquid is regenerated at a temperature of 80°C or higher, preferably 80°C to 130°C. Due to this high temperature, _{H 2 S is removed from the H 2} S absorption liquid, and the regenerated H ₂ S absorption liquid is supplied to the absorption tower 201 through a heat exchanger. _{As described above, the absorption process of absorbing H 2} S in the absorption tower 201 and the regeneration process of separating the _{absorbed H 2} S into a gas phase by applying thermal energy in the form of high-temperature steam 103 in the regeneration tower 202. This is repeated.

Meanwhile, in order to maintain the performance of the filter 203, the naphthalene filtered through the filter may be removed using a backwashing solution based on a given differential pressure or time interval.

At this time, the backwashing liquid may be _{an H 2} S absorbent liquid of 80°C or higher, preferably 80°C to 130°C, discharged from the regeneration tower 202 through the first backwashing line 301. Since the melting point of naphthalene is 80° C., naphthalene is melted or sublimated by backwashing the filter 203 using a high-temperature absorbing liquid of 80°C or higher, thereby maximizing the backwashing efficiency.

The backwashing liquid discharged after backwashing the filter 203 may be supplied to the regeneration tower 202 through the second backwashing line 302. As described above, since the operating temperature of the regeneration tower 202 is 80° C. or higher, most of the naphthalene contained in the backwash liquid is sublimated and discharged as a gas 104 through the upper portion of the regeneration tower 202. Therefore, a separate device for discharging naphthalene is not required, and naphthalene can be removed by a relatively simple method.

In addition, the backwashing liquid may be a surplus face or a filtered absorbent liquid (absorbent liquid after the filter). The filter 203 is backwashed using excess ordinal or filtered absorbent liquid, and the backwashing liquid discharged after backwashing is supplied to the regeneration tower 202 through the second backwashing line 302 as described above, or a circulating ordination decanter , Not shown) can be removed by sedimentation of a solid material such as naphthalene.

According to another aspect of the present invention, the H _{2 S absorption liquid in the absorption tower 201 absorbing H 2} S from the coke oven gas; Removing naphthalene from _{the H 2} S absorption liquid using a filter 203; And removing _{H 2 S from the H 2} S absorption liquid in the regeneration tower 202.

The technical features of the process mentioned in connection with the above-described coke oven gas purification apparatus are equally applied to the coke oven gas purification method.

Example

1. Examples

In the coke oven gas purification apparatus of the present invention as shown in FIG. 2, after passing through a filter having a pore diameter of 50 μm, the _{size distribution of naphthalene particles present in the H 2} S absorbing liquid is measured and shown in FIG. 3.

2. Comparative Example

In the conventional coke oven gas purification apparatus as shown in FIG. 1, the distribution of naphthalene particles contained in the _{H 2 S absorption liquid was measured and shown in FIG. 4.}

3. Naphthalene particle size distribution measurement result

_{In the case of the H 2} S absorbent that passed through the filter, Dv (10), Dv (50), and Dv (90) were 2.83 μm, 22.4 μm, and 95.7 μm, respectively, but in the case of the _{H 2 S absorbent that did not pass through the filter, Dv (} 10), Dv (50), and Dv (90) were 93.9 μm, 173 μm, and 301 μm, respectively. It can be seen that when a filter is installed in the coke oven gas purification apparatus, naphthalene having large particles is removed, and only naphthalene having small particles is _{present in the H 2 S absorption liquid. The total suspended solids (SS) of the H 2} S absorbent that did not pass through the filter was 139.6 mg/L, but after passing through the filter, the total suspended solids concentration was measured to be 2.2 mg/L, and the naphthalene removal rate was 98.4 %.

101: coke oven gas
102: coke oven gas from which acid gas has been removed
103: steam
104: gas containing naphthalene
201: absorption tower
202: regeneration tower
203: filter
204: H ₂ S absorption liquid tank
301: first backwash line
302: second backwash line

Claims (10)

An absorption tower in which the H _{2 S absorption liquid absorbs H 2} S from the coke oven gas;
A filter for removing naphthalene contained in _{the H 2} S absorption liquid discharged from the absorption tower; And
A regeneration tower connected to the absorption tower, removing _{H 2} S from the H ₂ S absorption _{liquid, regenerating the H 2 S absorption liquid, and supplying the H 2 S absorption liquid to the absorption tower;}
Including,
A first backwash line connecting a lower portion of the regeneration tower and a filter, and supplying a part of the _{H 2 S absorbent liquid discharged from the regeneration tower to the filter;} And
And a second backwash line _{connecting the filter and the upper part of the regeneration tower, and supplying the H 2} S absorbent liquid containing naphthalene to the upper part of the regeneration tower by backwashing the filter,
Naphthalene supplied to the regeneration tower through the second backwash line is sublimated and removed from the regeneration tower, and the H ₂ S absorption liquid is regenerated.
The method of claim 1,
The coke oven purification apparatus further comprises an H ₂ S absorption liquid tank in which the H _{2 S absorption liquid transferred through the filter is stored.}
The method of claim 1,
Coke oven gas purification apparatus, characterized in that the pore size of the filter is 10 ~ 500μm.
The method of claim 1,
The filter is a coke oven gas purifying apparatus, characterized in that the filter is backwashed by _{the H 2} S absorption liquid, the excess water, or the filtered absorption liquid discharged from the regeneration tower.
The method of claim 4,
When backwashing the filter, _{the temperature of the H 2} S absorption liquid discharged from the regeneration tower is 80° C. or higher.
_{Absorbing H 2} S from the coke oven gas by the H ₂ S absorbent liquid in the absorption tower and discharging the absorbent liquid absorbing _{H 2 S;}
Removing naphthalene contained in _{the H 2} S absorption liquid discharged from the absorption tower _{using a filter, and supplying the H 2} S absorption liquid to the regeneration tower; And
Removing _{H 2} S from the supplied H ₂ S absorption _{liquid in a regeneration tower, regenerating the H 2} S absorption liquid and supplying it to the absorption tower,
Supplying at least a portion of the _{H 2} S absorption liquid supplied to the absorption tower to the filter to backwash; And
_{Supplying the H 2} S absorbent liquid containing naphthalene to the upper part of the regeneration tower to sublimate and remove naphthalene, _{and regenerating the H 2} S absorbent liquid.
Coke oven gas purification method comprising a.
The method of claim 6,
A method for purifying a coke oven gas, further comprising the step of storing the _{H 2} S absorbent liquid that has passed through the filter in the H _{2 S absorbent liquid tank.}
The method of claim 6,
Coke oven gas purification method, characterized in that the pore size of the filter is 10 ~ 500μm.
The method of claim 6,
A method for purifying a coke oven gas, characterized in that the filter is backwashed by _{the H 2} S absorption liquid, the excess water, or the filtered absorption liquid discharged from the regeneration tower.
The method of claim 9,
A method for purifying a coke oven gas, characterized in that the temperature of _{the H 2} S absorption liquid discharged from the regeneration tower during backwashing of the filter is 80°C or higher.

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