KR100653046B1 - Method for removal of hydrogen sulfide by reaction of catalyst - Google Patents

Abstract

A method for removing hydrogen sulfide by a chemical reaction catalyst, which has excellent removal efficiency of hydrogen sulfide, is environmentally friendly without generating wastewater by using a catalytic reaction method, and can supply coke oven gas with reduced content of hydrogen sulfide, is provided. In a method for removing hydrogen sulfide contained in coke oven gas generated in the coke manufacturing process using a chemical reaction catalyst, a method for removing hydrogen sulfide by the chemical reaction catalyst comprises the steps of: (a) mixing iron hydroxide powder with zinc hydroxide powder to prepare a first catalyst pellet, and mounting the first catalyst pellet on a first reactor; (b) mixing iron hydroxide powder with iron powder to prepare a second catalyst pellet, and mounting the second catalyst pellet on a second reactor; and (c) passing coke oven gas through the first and second reactors on which the catalyst pellet is mounted at a space velocity of 50,000/hr or less to remove hydrogen sulfide through dry reaction. The first catalyst pellet of the step(a) contains 30 wt.% or more of zinc hydroxide powder. The second catalyst pellet of the step(b) contains 50 wt.% or more of zinc hydroxide powder.

Description

METHODS FOR REMOVAL OF HYDROGEN SULFIDE BY REACTION OF CATALYST}

1 is a flowchart illustrating a hydrogen sulfide removal process using a chemical reaction catalyst of the present invention.

Figure 2 is a graph showing the reaction removal rate (%) according to the mixing ratio of the iron hydroxide powder and zinc hydroxide powder of the catalyst of one embodiment and comparative examples of the present invention.

Figure 3 is a graph showing the sulfur removal rate (%) according to the mixing ratio of the iron hydroxide powder and zinc hydroxide powder of the catalyst of one embodiment and comparative examples of the present invention.

Figure 4 is a graph showing the hydrogen sulfide removal rate (%) according to the space velocity of one embodiment and comparative examples of the present invention.

The present invention relates to a method for removing hydrogen sulfide by a chemical reaction catalyst, and more particularly, the hydrogen sulfide removal efficiency is excellent, and it is environmentally friendly because there is no generation of waste water using a catalytic reaction method, and the content of hydrogen sulfide is reduced. The present invention relates to a method for removing hydrogen sulfide by a chemical reaction catalyst capable of providing a gas (COG).

Coke oven gas (coke oven gas, hereinafter referred to as 'COG'), tar and moisture are generated in the process of manufacturing coke by the coal mixing process. Among them, when tar and water are recovered and processed in a liquid state, gaseous COG is collected and used as an energy source in a steel mill through some purification processes.

This COG contains a part of hydrogen sulfide, which causes the release of SOx which adversely affects the air pollution during combustion. In addition, there is a process of refining COG in order to solve the air pollution, in which case there is a problem in reducing the efficiency of removing hydrogen sulfide in the use of ordinal water containing a large amount of ammonia generated in the process.

Korean Laid-Open Patent Publication No. 2002-0016136 (2002.03.04) discloses a method of selectively absorbing hydrogen sulfide contained in COG by removing water by contacting ordination and COG in an absorption tower. The method is to remove the hydrogen sulfide of the COG by contacting the COG with an aqueous solution of methyldiethanolamine (MDEA) having a concentration of 2 to 5 g / l at a gas-liquid contact ratio of 0.5 to 0.6, which is a wet process As this progresses, there is a problem that the process of removing methyldiethanolamine used in the process from ordination is included.

Korean Patent Publication No. 2002-0088688 discloses a method of removing hydrogen sulfide by a wet method by adjusting the concentration of ammonia solution. This method is similar to the general wet removal method by decreasing the flow rate by the increase of the ammonia solution.

This conventional method is difficult to efficiently remove the hydrogen sulfide contained in the COG, there is a disadvantage that the device is large and expensive.

In order to solve the problems of the prior art as described above, the present invention is excellent in the removal efficiency of hydrogen sulfide, environmentally friendly, there is no generation of waste water by using a catalytic reaction method, the coke oven gas (COG) is reduced hydrogen sulfide content It is an object of the present invention to provide a method for removing hydrogen sulfide by a chemical reaction catalyst which can be provided.

The above and other objects of the present invention can be achieved by the present invention described below.

In order to achieve the above object, the present invention is a method for removing the hydrogen sulfide contained in the coke oven gas (COG) generated during the coke production process with a chemical reaction catalyst,

(a) mixing the iron hydroxide powder and the zinc hydroxide powder to prepare a primary catalyst pellet and mounting it in the primary reactor;

(b) mixing the iron hydroxide powder and the iron powder to prepare a secondary catalyst pellet and mounting it in the secondary reactor; And

(c) passing the coke oven gas (COG) to the primary and secondary reactors equipped with the catalyst pellet at a space velocity of 50,000 / hour or less to remove hydrogen sulfide by dry reaction;

It provides a method for removing hydrogen sulfide by a chemical reaction catalyst comprising a.

Hereinafter, the present invention will be described in detail.

In order to solve the problems of the prior art, the present inventors, while conducting a study using a chemical reaction catalyst of hydrogen sulfide contained in COG, when the hydrogen sulfide chemically reacted with iron hydroxide to produce iron sulfide, zinc hydroxide reacts with hydrogen sulfide When zinc sulfide is produced and the reducing atmosphere is maintained by the COG component, the phenomenon of precipitation as elemental sulfur is confirmed, and thus, the present invention has been completed.

In the method of removing hydrogen sulfide by the chemical reaction catalyst of the present invention, hydrogen sulfide contained in COG is mixed with iron hydroxide powder and iron powder, zinc hydroxide powder is prepared as a pellet, and a chemical reaction with hydrogen sulfide is carried out to thereby carry out the chemical reaction with hydrogen sulfide. It is a method to remove hydrogen sulfide more efficiently.

Step (a) of the present invention is a step of preparing a primary catalyst pellet by mixing iron hydroxide powder and zinc hydroxide powder and mounting in the primary reactor.

Especially as said iron hydroxide powder, powders, such as gothite ((alpha) -FeOOH) or ferric hydroxide (Fe (OH) ₃ )), are preferable.

The primary catalyst pellets preferably have a content of zinc hydroxide powder of 30% by weight or more. If the content is more than 30% by weight, respectively, the reaction removal rate is excellent effect.

Step (b) of the present invention is a step of preparing a secondary catalyst pellet by mixing the iron hydroxide powder and iron powder and mounted in the secondary reactor.

In the secondary catalyst pellets, the content of zinc hydroxide powder is preferably 50% by weight or more. When the content is more than 50% by weight, respectively, there is an excellent effect of removing sulfur.

Preferably, the primary and secondary catalyst pellets are 3 to 5 mm in size. In the case of the size, there is no phenomenon that the surface area per unit area is not reduced, and the effect is excellent, and there is no problem such as the occurrence of internal closing phenomenon due to the problem of handling and breakage during use.

The step (c) of the present invention is a step of removing the hydrogen sulfide by dry reaction by passing COG at a space velocity of 50,000 / hour or less through the first and second reactors equipped with the catalyst pellet.

Space Velocity (SV) of COG input to the reactor is the amount of COG treated per hour passing through the catalyst pellet layer of the reactor divided by the catalyst pellet capacity, and the COG for the catalyst pellet capacity filled in 1 hour Indicates the amount of aeration to be processed. The space velocity is preferably 50,000 / hour or less.

The temperature of the primary and secondary reactors is preferably maintained at 30 ℃ or more. Since the hydrogen sulfide removal reaction of COG is a treatment reaction of flammable COG, it is preferable to keep the temperature as low as possible, and 30 ° C., which is a temperature at which the operation is possible without sufficient calorie input to the process, is preferable.

 The chemical reaction of hydrogen sulfide and catalyst pellets contained in COG of step (c) is shown in Scheme 1 below.

Scheme 1

H ₂ S + 2FeOOH → 2FeO + S + 2H ₂ O

H ₂ S + Zn (OH) ₂ → ZnS + 2H ₂ O

In other words, hydrogen ions in hydrogen sulfide react with gothite, an iron hydroxide powder, to form two water molecules. Among them, sulfur ions are oxidized to an electrically stable elemental sulfur state to precipitate and remove hydrogen sulfide contained in COG as a solid elemental sulfur. do.

Zinc hydroxide powder reacts directly with hydrogen sulfide to produce zinc sulfide and immobilize the sulfur of hydrogen sulfide while producing two water molecules.

In addition, the iron powder contained in the secondary catalyst pellet of the present invention promotes the reaction, and the chemical reaction of the reaction promoting phenomena of the iron powder and the zinc powder is shown in Scheme 2 below.

Scheme 2

Fe + S → FeS

Zn + S → ZnS

When the fine elemental sulfur contained in the COG is reacted with the iron powder and the zinc powder in the reaction of Scheme 2 to fix the iron sulfide, the hydrogen sulfide contained in the COG can be removed by a chemical reaction catalyst.

In the reactions of Schemes 1 and 2, the catalyst preferably contains 8% or more of zinc hydroxide powder and iron powder with respect to the iron hydroxide powder in consideration of the concentration of hydrogen sulfide contained in COG. When included in the content has the effect of maximizing the hydrogen sulfide removal efficiency by promoting the catalytic reaction.

After the completion of the step (c), the catalyst pellets are collected by desorption at the bottom of the reactor, injected at the top, and utilized in a continuous process, and after separation from the reactor, it is economical because it can be regenerated and used.

In the method of removing hydrogen sulfide by the chemical reaction catalyst of the present invention, the hydrogen sulfide removal rate is preferably 80% or more.

1 is a flowchart illustrating a method of removing hydrogen sulfide by a chemical reaction catalyst including the steps (a) to (c) of the present invention. According to FIG. 1, crude COG containing hydrogen sulfide is passed through a lower portion of a primary reactor equipped with primary catalyst pellets prepared by mixing iron hydroxide powder and zinc hydroxide powder to remove hydrogen sulfide, and then passed through the primary reactor. One COG was passed to the bottom of the secondary reactor equipped with secondary catalyst pellets prepared by mixing iron powder and zinc hydroxide powder to obtain purified COG without hydrogen sulfide at the top of the secondary reactor.

Hereinafter, preferred examples are provided to help understanding of the present invention, but the following examples are merely to illustrate the present invention, and the scope of the present invention is not limited to the following examples.

EXAMPLE

Examples 1-4 and Comparative Example 1. Preparation of catalyst pellets mounted in the primary reactor

To prepare a catalyst used in the primary reactor, iron hydroxide powder and zinc hydroxide powder were mixed in the composition shown in Table 1 below, prepared into pellets of 3 to 5 mm, and the pellets were mounted in the primary reactor.

The pellet-equipped primary reactor was passed through a COG with a hydrogen sulfide concentration of 0.93 mg / nm ³ at a space velocity of 25,000 / hour at 30 ° C. at the reactor inlet. The passed COG was measured by gas chromatography, and converted into a reaction removal rate of hydrogen sulfide, and the results are shown in FIG. 2.

division Iron hydroxide mixing ratio (% by weight) Zinc hydroxide mixing ratio (% by weight) Reaction removal rate (%) Example 1 50 50 92.3 Example 2 30 70 93.8 Example 3 20 80 95.2 Example 4 70 30 90.5 Comparative Example 1 80 20 75.4

According to Figure 2, the catalyst pellet mounted in the primary reactor, when the iron hydroxide powder and zinc hydroxide powder is mixed, when the mixing ratio of the zinc hydroxide powder is added at 30% by weight or more, the hydrogen sulfide reaction removal rate in the first reactor is 80% or more It was confirmed that the excellent.

Examples 5-7 and Comparative Examples 2-3. Preparation of Catalyst Pellets Mounted in Secondary Reactor

In order to prepare a catalyst used in the secondary reactor, iron powder and zinc hydroxide powder were mixed in the composition shown in Table 2 below, prepared into pellets of 3 to 5 mm, and then the pellet was mounted in the secondary reactor.

The pellet-equipped secondary reactor was passed through a COG with a hydrogen sulfide concentration of 0.93 mg / Nm ³ at a space velocity of 25,000 / hour at 30 ° C. at the reactor inlet. The sulfur removal rate of the passed COG was measured, and the results are shown in FIG. 3.

division Iron hydroxide mixing ratio (% by weight) Zinc hydroxide mixing ratio (% by weight) Sulfur Removal Rate (%) Example 5 50 50 85.4 Example 6 30 70 89.1 Example 7 20 80 91.5 Comparative Example 2 80 20 60.1 Comparative Example 3 70 30 71.2

According to FIG. 3, the catalyst pellets mounted in the secondary reactor have a sulfur removal rate of 80% or more in the secondary reactor when the iron hydroxide and the zinc hydroxide powder are mixed, when the mixing ratio of the zinc hydroxide powder is added by 50% by weight or more. It was confirmed that it was excellent.

Examples 8-12 and Comparative Examples 4-5. Hydrogen sulfide removal

In order to remove hydrogen sulfide contained in the COG, the primary catalyst pellets prepared in Example 1 and the secondary catalyst pellets prepared in Example 5 were mounted in the primary and secondary reactors, respectively.

First and second reactors equipped with the pellets were passed through a COG having a hydrogen sulfide concentration of 0.93 mg / Nm ³ at the reactor inlet at a temperature of 30 ° C. at the space velocity of Table 3 below. The hydrogen sulfide removal rate of the passed COG was measured, and the results are shown in FIG. 4.

division Space speed / time Hydrogen sulfide removal rate (%) Example 8 50,000 93.2 Example 9 40,000 95.8 Example 10 30,000 96.9 Example 11 20,000 98.0 Example 12 10,000 99.1 Comparative Example 4 60,000 83.7 Comparative Example 5 70,000 72.9

In general, when the space velocity is reduced, it is effective for removing hydrogen sulfide, whereas when the space velocity is increased, the contact reaction time between the reactant and the catalyst pellet is short, and thus the efficiency is decreased. However, according to FIG. 4, in the present invention, since the reaction was carried out using the secondary catalyst pellet, it was confirmed that the hydrogen sulfide removal rate was superior to 90% or more despite the low space velocity of 50,000 / hour or less.

As described above, according to the present invention, the removal efficiency of hydrogen sulfide is excellent, and it is environmentally friendly because there is no generation of waste water by using the catalytic reaction method, and the generation of SOx which increases the atmospheric environmental pollution during combustion due to the decrease of the content of hydrogen sulfide. It is effective to provide coke oven gas (COG) that can solve the problem. Although described in detail above with reference to the specific embodiments of the present invention, it will be apparent to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention, and such variations and modifications belong to the appended claims. It is also natural.

Claims (6)

In the method for removing hydrogen sulfide contained in the coke oven gas (COG) generated during the coke production process with a chemical reaction catalyst, (a) mixing the iron hydroxide powder and the zinc hydroxide powder to prepare a primary catalyst pellet and mounting it in the primary reactor; (b) mixing the iron hydroxide powder and the iron powder to prepare a secondary catalyst pellet and mounting it in the secondary reactor; And (c) passing the coke oven gas (COG) to the primary and secondary reactors equipped with the catalyst pellet at a space velocity of 50,000 / hour or less to remove hydrogen sulfide by dry reaction; Method for removing hydrogen sulfide by a chemical reaction catalyst, characterized in that comprises a. The method of claim 1, The primary catalyst pellet of step (a) is hydrogen sulfide removal method using a chemical reaction catalyst, characterized in that the content of zinc hydroxide powder is 30% by weight or more. The method of claim 1, The secondary catalyst pellet of step (b) is hydrogen sulfide removal method using a chemical reaction catalyst, characterized in that the content of zinc hydroxide powder is 50% by weight or more. The method of claim 1, The first and second catalyst pellets are hydrogen sulfide removal method using a chemical reaction catalyst, characterized in that the size of 3 to 5 mm. The method of claim 1, The method of removing hydrogen sulfide by a chemical reaction catalyst, characterized in that the temperature of the primary and secondary reactor is 30 ℃ or more. The method of claim 1, The hydrogen sulfide removal method using the chemical reaction catalyst is hydrogen sulfide removal method using a chemical reaction catalyst, characterized in that the hydrogen sulfide removal rate is 80% or more.

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