KR101795466B1 - Gas treating method and apparatus therefor - Google Patents

Abstract

A gas processing method of the present invention comprises the processes of: separating a carbon dioxide from a process gas by supplying a mixed gas in which the process gas is mixed with an ammonia gas to a carbon dioxide collector and cooling the mixed gas, thereby generating ammonium carbonate in which the carbon dioxide is collected; and separating hydrogen sulfide and ammonia and generating sodium hydrogen sulfide by collecting hydrogen sulfide from the process gas discharged from the carbon dioxide collector after the carbon dioxide is separated from the process gas. Therefore, the gas processing method according to embodiments of the present invention can improve the collection rate of hydrogen sulfide, and can accordingly improve quality of sodium hydrogen sulfide produced. Further, the gas processing method comprises including a plurality of carbon dioxide collectors, and alternately performing a process of generating ammonium carbonate in the operation of the plurality of carbon dioxide collectors, and a process of melting the generated ammonium carbonate. Accordingly, the gas processing method can continuously carry out the process of collecting carbon dioxide without the suspension of the process by supplying the process gas to the carbon dioxide collectors. Therefore, the gas processing method can purify a large amount of the process gas in a short time, and can increase an output of sodium hydrogen sulfide.

Description

TECHNICAL FIELD [0001] The present invention relates to a gas treating method and apparatus,

The present invention relates to a gas treatment method and a gas treatment apparatus, and more particularly, to a gas treatment method and a gas treatment apparatus capable of continuously purifying a process gas and increasing the production amount of sodium hydrogen sulfide produced in the purification process will be.

Coke oven gas (COG) generally contains various components such as carbon dioxide, hydrogen sulfide, ammonia, hydrogen cyanide, and the like, which are supplied to the gas piping Which may cause corrosion or clogging. When the coke oven gas is used as the fuel, it causes pollution, so the acid gas is used at a certain concentration or lower.

In particular, hydrogen sulfide is a material that is highly corrosive to air pollution and odors caused by sulfuric acid water. The hydrogen sulfide in the acidic gas is separated and removed by supplying ammonia to the hydrogen sulfide absorption tower and absorbing hydrogen sulfide in the ammonia.

However, the carbon dioxide contained in the acid gas causes the hydrogen sulfide absorption tower to obstruct the collection of hydrogen sulfide. That is, when hydrogen sulfide is absorbed by ammonia, the absorption rate of hydrogen sulfide decreases as carbon dioxide is also absorbed.

Therefore, it is necessary to separate carbon dioxide, which is actively developing technologies that meet the characteristics of each process through the development of CCUS (Carbon Capture, Utilization, and Storage) technology. However, it is easy to remove carbon dioxide under the condition of a small amount of hydrogen sulfide However, when hydrogen sulfide is contained at a high concentration, it is difficult to remove carbon dioxide.

Korean Published Patent Application No. 2005-0029924

The present invention provides a gas processing method and a gas processing apparatus capable of continuously purifying a process gas without interruption.

The present invention provides a gas treatment method and a gas treatment apparatus capable of increasing the production amount of sodium hydrogen sulfide produced during purification treatment of a process gas.

The method of treating a gas according to the present invention is a method of treating a gas by supplying a mixed gas in which a process gas and an ammonia gas are mixed to a carbon dioxide sorter to cool the gas mixture to generate carbonic acid ammonium salt trapped with the carbon dioxide, And collecting the hydrogen sulfide from the process gas discharged from the carbon dioxide sorter by separating the carbon dioxide, separating the hydrogen sulfide and the ammonia, and generating sodium hydrogen sulfide.

Melting the ammonium carbonate salt in the carbon dioxide collector; Supplying the molten ammonium carbonate to a salt decomposer, and heating the molten ammonium carbonate salt to decompose the molten ammonium carbonate into a gaseous state; And separating the carbon dioxide and the ammonia by reacting the ammonia in the gas provided from the gas decomposer with the washing water to absorb the ammonia into the washing water.

And separating the hydrogen cyanide from the process gas discharged from the carbon dioxide collector before the capturing of the hydrogen sulfide.

The ammonia separated from the carbon dioxide is reused as an ammonia gas to be mixed with the process gas.

In cooling the mixed gas, the mixed gas is indirectly cooled to a temperature of 60 ° C or lower.

In heating and melting the ammonium carbonate, the carbon dioxide collector is heated and water is added.

In the process of decomposing the ammonium carbonate salt in the salt decomposer into a gaseous state, a heat exchange method using steam is used.

The plurality of carbon dioxide collecting units are provided, and in the plurality of carbon dioxide collecting units, the generation process of the ammonium carbonate and the melting process of the produced carbonic acid are alternately performed.

The mixed gas is alternately supplied to the plurality of carbon dioxide sorters, and the mixed gas is continuously treated through the plurality of carbon dioxide sorters.

In each of the plurality of carbon dioxide sorters, the carbon dioxide sorter is cooled to prepare a salt for ammonium carbonate formation; A salt producing process for producing the ammonium carbonate salt by supplying the mixed gas to the cooled carbon dioxide collector and cooling it; A condensed water produced in the course of the ammonium carbonate salt process and a process gas discharge process for discharging the process gas from which the carbon dioxide is separated to the outside of the carbon dioxide collector; A salt melting process for heating and melting ammonium carbonate in the carbon dioxide collector; And a salt discharging step of discharging the molten ammonium carbonate to the salt decomposer, wherein at least one of the plurality of carbon dioxide trappers is subjected to a salt formation process, a condensate and a treatment Other processes are performed during the gas discharge process, salt melt process, salt discharge process, and salt production preparation process.

The plurality of carbon dioxide collectors perform different processes.

At least one of the plurality of carbon dioxide sorters performs a different process than the other plurality of carbon dioxide sorters, and the other plurality of carbon dioxide sorters performs the same process.

A carbon dioxide collector for separating the carbon dioxide from the process gas by cooling a mixed gas obtained by mixing a process gas and an ammonia gas to collect carbon dioxide in the process gas to produce an ammonium carbonate salt; And a hydrogen sulfide sorter for collecting hydrogen sulfide from the process gas discharged from the carbon dioxide sorter by separating the carbon dioxide to produce sodium hydrogen sulfide.

The carbon dioxide sorbent melts the produced ammonium carbonate salt.

A salt decomposer which receives molten ammonium carbonate from the carbon dioxide sorter and decomposes the ammonium carbonate salt into a gaseous state by heating; And an ammonia scrubbing tower for separating carbon dioxide and ammonia by reacting the gas produced in the salt decomposer with the cleansing water to absorb the ammonia in the cleansing water.

And a cyanide hydrogen collector for separating the hydrogen cyanide from the separated process gas before the carbon dioxide separated process gas is transferred to the hydrogen sulfide collector.

A plurality of carbon dioxide collectors are provided, a plurality of processes are performed in each of the plurality of carbon dioxide collectors, and during one of the plurality of processes in one carbon dioxide collector, , Another work process is carried out.

The plurality of carbon dioxide collectors are operated such that the generation process of the ammonium carbonate and the melting process of the generated carbonic acid are alternately performed.

At the same time, the plurality of carbon dioxide collectors perform different processes such as a salt production process, a condensed water and a process gas discharge process, a salt melt process, a salt discharge process, and a salt production preparation process.

The salt decomposer is gasified by alternately supplying the ammonium carbonate salt melted from the plurality of carbon dioxide sorters.

The gas treatment apparatus according to the embodiment of the present invention can selectively collect carbon dioxide before hydrogen sulfide capture, thereby improving the hydrogen sulfide capture rate and improving the quality of the produced sodium hydrogen sulfide.

The gas processing apparatus according to the embodiment of the present invention includes a plurality of carbon dioxide collectors, and in the operation of a plurality of carbon dioxide collectors, the process of producing ammonium carbonate and the process of melting the produced carbonic acid are alternately . Therefore, the process gas can be supplied to the carbon dioxide sorter, and the process of collecting the carbon dioxide can be continuously performed without interruption. Therefore, a large amount of the processing gas can be purified in a short time, and the production amount of sodium hydrogen sulfide can be increased.

1 is a block diagram conceptually showing a gas processing apparatus according to an embodiment of the present invention;
2 is a diagram illustrating the operation of a plurality of carbon dioxide sorters;

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know. Wherein like reference numerals refer to like elements throughout.

The present invention relates to a gas processing apparatus and a gas processing method for separating or purifying hydrogen sulfide which generates air pollution and odor from a gas (object to be treated) containing an acid gas such as carbon dioxide, hydrogen sulfide and ammonia. More specifically, the present invention relates to a gas processing apparatus and method for separating hydrogen sulfide from an acidic process gas containing carbon dioxide, hydrogen sulfide, and ammonia, which improves separation and removal efficiency of hydrogen sulfide and improves the quality and productivity of sodium hydrogen sulfide, And a gas treatment method.

Here, the process gas containing an acidic gas such as carbon dioxide, hydrogen sulfide, ammonia, etc. may be a coke oven gas generated during the process of producing coke by carburizing coal in a coke oven, or may be an exhaust gas generated in a desulfurization process.

Hereinafter, a gas processing apparatus according to an embodiment of the present invention will be described with reference to Figs. 1 and 2. Fig. Hereinafter, the gas to be treated or purified by the gas processing apparatus according to the embodiment of the present invention is referred to as a 'process gas'. The process gas is an acidic gas containing at least carbon dioxide, hydrogen sulfide, ammonia, and the like.

1 is a block diagram conceptually showing a gas processing apparatus according to an embodiment of the present invention. 2 is a diagram illustrating the operation of a plurality of carbon dioxide collectors.

Since the process gas apparatus according to the embodiment of the present invention produces sodium hydrogen sulfide by its operation, it can also be referred to as an apparatus for producing sodium hydrogen sulfide.

Referring to FIG. 1, a gas processing apparatus according to an embodiment of the present invention includes a gas mixer 100 for mixing a process gas, which is an object to be purified, with ammonia gas (NH ₃ gas) and steam, A carbon dioxide collector 200 for cooling the mixed gas in which ammonia gas and steam are mixed to separate carbon dioxide and performing carbon dioxide separation, and a carbon dioxide collector 200 for receiving the carbon dioxide- An ammonia scrubbing tower 420 for separating carbon dioxide and ammonia by absorbing ammonia from a gaseous product delivered from the salt decomposer 410; And an ammonia collector 500 for collecting ammonia water as a product of the tower 420. A hydrogen sulfide collector 320 for collecting hydrogen sulfide from the process gas from which carbon dioxide is removed from the plurality of carbon dioxide sorters 200, and an ammonia sorter for collecting ammonia from the process gas from which hydrogen sulfide is removed.

Before transferring the process gas from which carbon dioxide has been removed in the carbon dioxide sorter 200 to the hydrogen sulfide sorter 320, the hydrogen cyanide is separated from the process gas from which the carbon dioxide has been removed and transferred to the hydrogen sulfide sorter 320. And a trapper 310.

In the gas mixer 100, a process gas, which is an acid gas, and an ammonia gas are mixed. At this time, high temperature steam is further mixed for effective reaction of the process gas and the ammonia gas. Of course, if the process gas itself contains moisture, there is no need to further mix the steam. The amount of ammonia gas to be removed depends on the amount of carbon dioxide to be removed before the removal of hydrogen sulfide in the treatment gas. The amount of the ammonia gas to be removed is 1: 2 (carbon dioxide: ammonia = 1: 2) or more.

In the carbon dioxide sorter 200, a mixed gas in which a process gas and an ammonia gas are mixed is cooled to induce a reaction between carbon dioxide and ammonia in the mixed gas to generate an ammonium carbonate salt, whereby a salt containing carbon dioxide (ammonium carbonate salt) Hydrogen sulfide, ammonia, hydrogen cyanide, and the like. That is, hydrogen sulfide, ammonia, and hydrogen cyanide are not captured as much as possible from the process gas, but only carbon dioxide is selectively captured and separated.

To cool the mixed gas in the carbon dioxide sorter 200, the carbon dioxide sorter 200 is treated at 60 ° C or lower, more preferably at 50 ° C or lower. This is because the reaction between carbon dioxide and ammonia occurs at a temperature of 60 占 폚 or lower, and an ammonium carbonate salt is produced. When the carbon dioxide sorter 200 is overcooled, other gases (sulfur gas or ammonia gas) besides carbon dioxide which is a target component are condensed together and can be separated and removed together.

In the embodiment, the temperature of the carbon dioxide sorter 200 is adjusted to 60 ° C by indirect cooling using the cooling water to cool the carbon dioxide sorter 200 to 60 ° C or less.

As described above, in the embodiment of the present invention, the mixed gas, which is the processing gas supplied into the carbon dioxide sorter 200, is cooled indirectly rather than directly. This is because, when cooling water is supplied into the carbon dioxide sorter 200 to cool the mixed gas and the cooling water in direct contact with each other, the carbon dioxide is condensed in the salt or the separation efficiency And the indirect cooling is efficient because the process of producing the by-product solution is accompanied.

When the ammonium carbonate salt is produced in the carbon dioxide sorter 200, the process gases (including hydrogen sulfide, ammonia, and hydrogen cyanide) other than the ammonium carbonate salt are transferred to the subsequent treatment facility, that is, the hydrogen cyanide hydrogen sorbent or the hydrogen sulfide sorbent.

In the carbon dioxide sorter 200, the carbonic acid ammonium salt remaining in the carbon dioxide sorbent 200 does not move but dissolves or melts. The ammonium carbonate salt is easily dissolved and decomposed by moisture or heat. Accordingly, in the embodiment, the ammonium carbonate salt is dissolved by using steam containing both water and heat to make slurry.

The salt decomposer 410 decomposes by heating the slurry ammonium carbonate salt, which is a product of the carbon dioxide sorter 200, and gasifying it. That is, in the salt decomposer 410, the ammonium carbonate salt is heated to decompose into a gaseous phase. The salt decomposer according to the embodiment decomposes by vaporizing or gasifying the ammonium carbonate in a slurry state through a heat exchange action between steam at a temperature of 90 ° C or higher and ammonium carbonate. At this time, the product gas in the salt decomposer 410 may include carbon dioxide and ammonia gas which has moved to the outside of the carbon dioxide sorter 200 but has not escaped from the carbon dioxide sorbent and has remained in the ammonium carbonate. Thus, the ammonium carbonate salt is decomposed into carbon dioxide gas, ammonia, and water through heating in the salt decomposer 410.

The ammonia scrubbing tower 420 absorbs the ammonia in the cleaning water separately supplied from the carbon dioxide and ammonia gas delivered from the salt decomposer 410 to separate the carbon dioxide and ammonia. When the ammonia is absorbed into the washing water, the washing water becomes ammonia water, and the carbon dioxide separated from the ammonia is discharged to the outside through the upper side of the ammonia washing tower 420.

In the ammonia scrubbing tower 420 according to the embodiment, water is used as the washing water. However, the present invention is not limited to this, and it is possible to use a washing water containing another solution which is in contact with the gas and is easy to absorb and remove ammonia contained in the gas Can be used.

In the ammonia collector 500, heat is applied to ammonia water to separate cleansing water and ammonia gas. The ammonia gas generated in the ammonia collector 500 is recovered and supplied to a gas mixer to be reused as a gas mixed with the process gas.

Thus, while separating carbon dioxide and ammonia from the ammonium carbonate, the processing gases (including hydrogen sulfide, ammonia, and hydrogen cyanide) except the ammonium carbonate salt are transferred to the subsequent treatment facility, that is, the cyanide hydrogen collector 310 or the hydrogen sulfide collector 320.

The hydrogen cyanide hydrogen sorter 310 collects hydrogen cyanide from the process gas delivered from the carbon dioxide sorter 310. The sulfur cyanide hydrogen sorter 310 introduces sulfur (S) Cyanic ammonium salt (NH ₄ SCN). That is, the hydrogen cyanide is collected in the solid ammonium thiocyanate (NH ₄ SCN), whereby the unreacted hydrogen sulfide and hydrogen cyanide are separated.

The ammonium thiocyanate (NH ₄ SCN) in which hydrogen cyanide is captured is fixed or remained in the hydrogen cyanide collector 310, and the hydrogen sulfide and ammonia are transferred to the hydrogen sulfide collector 320, which is a subsequent process.

On the other hand, when the hydrogen cyanide in the process gas is contained in a trace amount so as not to affect the quality of the product, sodium hydrogen sulfide, the hydrogen cyanide capture step may be omitted.

In the hydrogen sulfide sorter 320, hydrogen sulfide is converted into sodium hydrogen sulfide to separate hydrogen sulfide and ammonia. In this process, sodium hydrogen sulfide is produced. To this end, a sodium hydroxide (NaOH) solution is added to the hydrogen sulfide sorter 320 to produce an aqueous solution of sodium hydrogen sulfide through reaction between hydrogen sulfide and sodium hydroxide, thereby separating ammonia and hydrogen sulfide. That is, in the process gas that has been transferred to the hydrogen sulfide sorter 320, hydrogen sulfide reacts with the input sodium hydroxide to become sodium hydrogen sulfide, and ammonia is not reacted with sodium hydroxide and is maintained in the ammonia state, and hydrogen sulfide and ammonia are separated therefrom. Sodium hydrogen sulfide is discharged from the hydrogen sulfide sorter 320. The ammonia gas is discharged from the hydrogen sulfide sorter 320 and then re-supplied to the gas mixer or collected by the ammonia collector and then supplied to the ammonia scrubbing tower 420 Ammonia water. Ammonia water can be used in appropriate places depending on the concentration and quality, and can be sold as ammonia water after a separate refining operation.

The sodium hydrogen sulphide produced in the hydrogen sulfide sorbent 320 in the hydrogen sulfide sorption process can be used in various industrial processes, for example, as a water treatment agent for removing heavy metals in wastewater or in a plating process. The concentration of the sodium hydrogen sulfide aqueous solution produced in the hydrogen sulfide sorter 320 depends on the amount of hydrogen sulfide contained in the process gas and the amount of sodium hydroxide to be added. Therefore, it is preferable to adjust the concentration of sodium hydrogen sulfide in accordance with the intended use of the sodium hydrogen sulfide.

The gas treatment apparatus according to the present invention may include a plurality of carbon dioxide collectors 200a, 200b, and 200c. In each of the carbon dioxide sorters 200a, 200b and 200c, as described above, the process of cooling the process gas to produce the carbonic acid ammonium salt trapped with carbon dioxide, and the process of melting the ammonium carbonate salt are sequentially performed. do. That is, in one carbon dioxide collector, a step of cooling the mixed gas to produce an ammonium carbonate salt, an exhausting step of discharging a process gas containing condensed water and carbon dioxide separated from the cooling step, water and ammonia separated from the carbon dioxide, And discharging the molten ammonium carbonate salt are sequentially carried out. In this embodiment, before the mixed gas is introduced into the carbon dioxide trapper, the carbon dioxide trapper is cooled in advance to a temperature at which the salt is easily produced, which is called the salt production preparation stage. Also, the step of producing ammonium carbonate is carried out by introducing a mixed gas into a carbon dioxide collector which has been previously cooled in the salt production preparation step, which is referred to as a salt production step. In other words, the process steps in one carbon dioxide sorter can be summarized as follows: In the carbon dioxide sorter, the 'salt production stage-condensate and process gas discharge stage-ammonium carbonate salt melting stage-ammonium carbonate discharge stage-salt production preparation stage' This cycle is repeated a plurality of times.

At this time, in operating the plurality of carbon dioxide collectors 200a, 200b, and 200c, different steps are performed in each of the plurality of carbon dioxide collectors 200a, 200b, and 200c so that each of the plurality of carbon dioxide collectors 200a, 200b, and 200c. In other words, by allowing the plurality of carbon dioxide collectors 200a, 200b, and 200c to perform processes at different stages during the process of purifying the process gas, the plurality of carbon dioxide sorters 200a, 200b, 200c), the salt-forming step and the salt-dissolving step can be alternately performed in a staggered manner.

For example, in the plurality of carbon dioxide collectors 200a, 200b, and 200c, the salt generation step and the salt dissolution step are alternately performed. In other words, in the case of producing a carbonic acid ammonium salt in one carbon dioxide sorbent (salt formation step), another step other than the salt production step in the other carbon dioxide sorbent, for example, dissolving ammonium carbonate salt (salt dissolution step) is performed .

In other words, in the step of transferring the process gas from which the carbon dioxide has been removed in any one of the plurality of carbon dioxide sorters 200a, 200b, 200c to a subsequent stage, and in the step of melting the ammonium carbonate salt, So that the ammonium carbonate salt is formed by cooling the gas. That is, while the carbonic acid ammonium salt produced in any one carbon dioxide collector is melted, another carbon dioxide collector collects ammonium carbonate. To this end, the mixed gas mixed in the gas mixer 100 is supplied to the plurality of carbon dioxide collectors 200a, 200b, and 200c by alternately or sequentially supplying the mixed gas. That is, since the mixed gas in which the shortage gas is mixed is continuously supplied to the plurality of carbon dioxide sorters 200a, 200b, and 200c sequentially or alternately, the process of stagnating the process gas can be continuously performed. Thus, the purification amount of the process gas and the production amount of sodium hydrogen sulfide are improved.

Hereinafter, with reference to FIG. 1 and FIG. 2, a more specific example of the operation of a plurality of carbon dioxide collectors according to an embodiment of the present invention will be described. At this time, for example, three carbon dioxide collectors are provided. For the sake of convenience of explanation, the processing time period for purifying the processing gas is divided into time points A, B, C, and D in time sequence.

For example, in the first carbon dioxide sorter 200a at the time point A, a salt generation step is performed in which a mixed gas in which a process gas and an ammonia gas are mixed is added to a precooler (prepared for salt formation) beforehand to generate an ammonium carbonate salt, The second carbon dioxide sorter 200b is performing a step of melting the ammonium carbonate salt generated before the point A and discharging the ammonium carbonate salt before the point A in the third carbon dioxide sorter 200c at the point A It is in progress.

At the time point B, the first carbon dioxide sorter 200a separates the process gas containing the gas obtained by separating the condensed water and the carbon dioxide produced during the production of the ammonium carbonate salt from the A point, that is, the hydrogen sulfide and the ammonia gas into the outside of the first carbon dioxide sorter 200a . At the same point in time B, the second carbon dioxide sorter 200b discharges the molten carbonate ammonium salt at the point A and transfers it to the salt decomposer 410. At the point B, the third carbon dioxide sorter 200c includes the process gas To produce an ammonium carbonate salt.

Although not described in detail later, different steps are performed in the first to third carbon dioxide collectors 200a, 200b, and 200c at the point C and the point D, respectively.

At this time, the operation periods of the plurality of carbon dioxide collectors 200a, 200b and 200c are determined in consideration of the concentration of the acid gas contained in the process gas, the generation of ammonium carbonate, the melting and the decomposition time. In addition, the plurality of carbon dioxide collectors 200a, 200b, and 200c can be alternately operated so that the generation and melting of ammonium carbonate alternately occur.

In the above description, different steps are performed in the plurality of carbon dioxide sorters. However, at least one of the plurality of carbon dioxide sorters may be processed at a different stage from the other carbon dioxide sorters. That is, a plurality of carbon dioxide collectors among the plurality of collectors may perform the same step. For example, if three or more carbon dioxide capture devices are provided, at least one carbon dioxide capture device may perform a different process than the other two or more carbon dioxide capture devices, and the two other carbon dioxide capture devices may perform the same process.

Hereinafter, with reference to Tables 1 to 3, the carbon dioxide removal rate, the hydrogen sulfide concentration in the exhaust gas, and the hydrogen sulfide removal rate will be described at the time of purifying the process gas using the gas processing apparatuses according to the examples and the comparative examples of the present invention.

At this time, in the experiments, the first and second embodiments and the first to third comparative examples used a treatment gas containing 50 wt% of carbon dioxide as the object to be treated.

Table 1 shows the results of purifying the process gas by the method according to the first embodiment and the first comparative example of the present invention. The first embodiment is a result of collecting carbon dioxide and collecting hydrogen sulfide by cooling the mixed gas containing the process gas supplied into the carbon dioxide collector with the cooling water at 27 ° C. The first comparative example is a result of collecting carbon dioxide and collecting hydrogen sulfide by indirect cooling using nitrogen gas cooled at a temperature of 16 캜 using a chiller.

division First Embodiment Comparative Example 1 Cooling water supply temperature 27 ℃ 16 ℃ Acid gas flow rate 75 Nm ³ / hr Ammonia gas input 20 Nm ³ / hr Cooling water discharge temperature 32 ℃ 19 ℃ Carbon dioxide trap internal temperature 36 ℃ 25 ℃ Carbon dioxide removal rate 98% 98% Hydrogen sulfide concentration in flue gas 79% 23%

Referring to Table 1, the carbon dioxide capture rates of the first embodiment and the first comparative example are similar to each other at 98%. However, the concentration of hydrogen sulfide in the flue gas discharged from the carbon dioxide separator separated from carbon dioxide is 79% in the first embodiment and 23% in the first comparative example, which is high in the first embodiment. Here, since the exhaust gas discharged from the carbon dioxide collector is transferred to the hydrogen sulfide collector and the hydrogen sulfide is collected to produce sodium hydrogen sulfide, the higher the concentration of hydrogen sulfide in the flue gas of the carbon dioxide collector, the more the production amount of sodium hydrogen sulfide is increased. Therefore, it can be seen from the experimental results shown in Table 1 that the indirect cooling using the cooling water can secure the economical efficiency of the process compared with the case of using the chiller.

division Comparative Example 2 Comparative Example 3 Cooling water supply temperature 27 ° C (primary) + 27 ° C (secondary) 27 캜 (primary) + 16 캜 (secondary) Acid gas flow rate 75 Nm ³ / hr Ammonia gas input 20 Nm ³ / hr Cooling water discharge temperature 32 ℃ 19 ℃ Carbon dioxide removal rate 99% 99% Hydrogen sulfide concentration in flue gas 3% Less than 1%

Table 2 shows that the first and second carbon dioxide collectors are connected in series to the second comparative example and the third comparative example, regardless of the cooling method, so that the first carbon dioxide captured gas in the first carbon dioxide collector (i.e., This is an experimental result showing the concentration of hydrogen sulfide in the exhaust gas when the second carbon dioxide capture is carried out in the second carbon dioxide sorter. In the third comparison, the cooling temperature at the time of collecting the primary carbon dioxide was 27 占 폚, the cooling temperature at the time of collecting the secondary carbon dioxide Is 16 [deg.] C.

Comparing the first embodiment of Table 1 with the second and third comparative examples of Table 2 shows that the first embodiment in which the carbon dioxide capture is performed once and the second and third implementations in which the carbon dioxide is conducted twice in succession It can be confirmed that the concentration of hydrogen sulfide in the exhaust gas is significantly lower than that in the first embodiment in the case of the second and third comparative examples. From this, it can be seen that there is a similar or similar effect that the carbon dioxide capture rate of one step of carbon dioxide capture using the carbon dioxide capture device according to the embodiment of the present invention is similar to or the same as the case where the carbon dioxide capture rate progresses a plurality of times continuously, It can be confirmed that it is effective to carry out the hydrogen sulfide capture once.

Table 3 shows the results of experiments in which two carbon dioxide collectors according to an embodiment of the present invention were provided and the treatment gas was continuously treated for 6 hours to produce sodium hydrogen sulfide.

division Second Embodiment Cooling water supply temperature 27 ℃ Acid gas flow rate 75 Nm ³ / hr Ammonia gas input 20 Nm ³ / hr NaOH input 85 kg Carbon dioxide trap internal temperature 87 ℃ PH 10 Hydrogen sulphide production 152 kg Hydrogen sulfide removal rate 99%

By collecting carbon dioxide and hydrogen sulfide under the same conditions as in Table 3, the process gas containing carbon dioxide of 50 wt% or more can be purified for 6 hours or more using the gas treatment apparatus according to the present invention, and sodium hydrogen sulfide can be continuously produced can confirm.

As described above, the gas treatment apparatus according to the embodiment of the present invention can selectively collect carbon dioxide before hydrogen sulfide capture, thereby improving the hydrogen sulfide capture rate, thereby improving the quality of the produced sodium hydrogen sulfide. The plurality of carbon dioxide sorters 200a, 200b, and 200c, including the plurality of carbon dioxide sorters 200, are operated alternately so that the generation process of ammonium carbonate and the melting process of the generated carbonic acid are interchanged alternately . Thus, the process gas can be supplied to the carbon dioxide sorter 200, and the process of collecting the carbon dioxide can be continuously performed without interruption. Therefore, a large amount of the processing gas can be purified in a short time, and the production amount of sodium hydrogen sulfide can be increased.

100: gas mixer 200a, 200b, 200c: carbon dioxide collector
320: hydrogen sulfide collector

Claims (20)

Separating the carbon dioxide from the process gas by supplying a mixed gas in which a process gas and an ammonia gas are mixed to the carbon dioxide sorter to cool the gas mixture to produce the carbonic acid ammonium salt trapped by the carbon dioxide; And
Collecting hydrogen sulfide from the process gas discharged from the carbon dioxide sorter by separating the carbon dioxide, separating the hydrogen sulfide and ammonia, and generating sodium hydrogen sulfide;
Melting the ammonium carbonate salt in the carbon dioxide collector;
Supplying the molten ammonium carbonate to a salt decomposer, and heating the molten ammonium carbonate salt to decompose the molten ammonium carbonate into a gaseous state; And
And separating the carbon dioxide and the ammonia by reacting the ammonia in the gas provided from the salt decomposer with the washing water to absorb the ammonia in the washing water. delete The method according to claim 1,
And separating the hydrogen cyanide from the process gas discharged from the carbon dioxide collector before the capturing of the hydrogen sulfide, thereby separating the hydrogen cyanide. The method according to claim 1,
And the ammonia separated from the carbon dioxide is reused as an ammonia gas to be mixed with the process gas. The method according to claim 1,
Wherein the mixed gas is indirectly cooled at a temperature of 60 DEG C or less in cooling the mixed gas. The method according to claim 1,
Wherein the carbon dioxide collector is heated and water is added for heating and melting the ammonium carbonate. The method according to claim 1,
And a heat exchange method using steam in the process of decomposing the ammonium carbonate salt into a gaseous state by heating the ammonium carbonate salt in the salt decomposer. The method according to any one of claims 3 to 7,
Wherein the plurality of carbon dioxide collecting units are alternately provided in the plurality of carbon dioxide collecting units so that the generation process of the ammonium carbonate and the melting process of the generated ammonium carbonate are carried out alternately alternately. The method of claim 8,
Wherein the mixed gas is alternately supplied to the plurality of carbon dioxide sorters, and the mixed gas is continuously treated through the plurality of carbon dioxide sorters. The method of claim 9,
In each of the plurality of carbon dioxide collectors,
A step of preparing a salt for producing ammonium carbonate by cooling the carbon dioxide collector;
A salt producing process for producing the ammonium carbonate salt by supplying the mixed gas to the cooled carbon dioxide collector and cooling it;
A condensed water generated in the process of producing the ammonium carbonate salt, and a process gas discharge process for discharging the process gas from which the carbon dioxide is separated to the outside of the carbon dioxide collector;
A salt melting process for heating and melting ammonium carbonate in the carbon dioxide collector; And
A salt discharge process in which the molten ammonium carbonate is discharged to the salt decomposer;
Are sequentially performed,
Wherein at least one of the plurality of carbon dioxide capture devices performs another of the salt formation process, the condensate and process gas discharge process, the salt melt process, the salt discharge process, and the salt production preparation process at the same time as the other carbon dioxide capture device. The method of claim 10,
Wherein the plurality of carbon dioxide sorters perform different processes. The method of claim 10,
Wherein at least one of the plurality of carbon dioxide sorters performs a different process than the other plurality of carbon dioxide sorters, and the other plurality of carbon dioxide sorters perform the same process. A carbon dioxide collector for separating the carbon dioxide from the process gas by cooling a mixed gas in which a process gas and an ammonia gas are mixed to collect carbon dioxide in the process gas to produce ammonium carbonate; And
A hydrogen sulfide sorter for separating the carbon dioxide from the process gas discharged from the carbon dioxide sorter to produce hydrogen sulfide to produce sodium hydrogen sulfide;
A salt decomposer which receives molten ammonium carbonate from the carbon dioxide sorter and decomposes the ammonium carbonate salt into a gaseous state by heating;
An ammonia scrubbing tower for separating carbon dioxide and ammonia by reacting the gas generated from the salt decomposer with the scrubbing water to absorb the ammonia into the scrubbing water;
And a gas processing device. 14. The method of claim 13,
And the carbon dioxide collector collects the generated ammonium carbonate salt. delete 14. The method of claim 13,
And a cyanide hydrogen collector for separating the hydrogen cyanide from the separated process gas before the carbon dioxide separated process gas is transferred to the hydrogen sulfide collector. 18. The method of claim 16,
A plurality of carbon dioxide collectors are provided,
A plurality of processes are performed in each of the plurality of carbon dioxide collectors,
Wherein one of the plurality of processes is performed in one of the plurality of processes in the one carbon dioxide sorter while the other process is performed in the other one of the plurality of processes in the one carbon dioxide sorter. 18. The method of claim 17,
Wherein the plurality of carbon dioxide sorters are operated such that the generation process of the ammonium carbonate and the melting process of the ammonium carbonate produced are alternately performed alternately. 19. The method of claim 18,
Wherein the plurality of carbon dioxide sorters perform different processes during the salt generation process, the condensed water and the process gas discharge process, the salt melt process, the salt discharge process, and the salt production preparation process at the same time. 19. The method of claim 18,
Wherein the salt decomposer is alternately supplied with the ammonium carbonate salt melted from the plurality of carbon dioxide sorters to gasify the carbonic acid ammonium salt.

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