KR101199473B1 - Apparatus for separating and recovering acid gas - Google Patents

Abstract

An acid gas separation and recovery apparatus of the present invention includes: an absorption tower for countercurrently contacting an absorbent with an exhaust gas including an acid gas to generate an acid gas saturated absorbent; A stripping column for separating the acid gas saturated absorbent into an acid gas and an absorbent by using thermal energy to regenerate the absorbent; A steam generator for generating steam by vaporizing supplemental water supplied to the absorption tower; And a nozzle installed in the stripping column and spraying the steam to counter-currently contact the acidic gas saturated absorbent and the steam to provide the thermal energy to the stripping column.
According to the present invention, since the vaporized water vapor can be injected directly to the stripping column through the nozzle to supply the absorbent renewable energy, there is an effect of efficiently supplying the absorbent renewable energy to the stripping column.

Description

Acid gas separation and recovery device {APPARATUS FOR SEPARATING AND RECOVERING ACID GAS}

The present invention relates to an acid gas separation recovery apparatus, and more particularly, to an acid gas separation recovery apparatus using condensed water and supplemental water as an energy source for vaporizing condensate and replenishing water to regenerate an absorbent.

As the industry develops, the concentration of acidic gases such as carbon dioxide (CO ₂ ), methane (CH ₄ ), hydrogen sulfide (H ₂ S), carbonyl sulfide (COS), etc. increases in the atmosphere. Internationally, efforts are being made to prevent global warming by tightening regulations on the emission and disposal of acid gases.

Among the acid gases that cause global warming, carbon dioxide accounts for more than 50% of the emitted acid gas, and much research is being conducted on technologies for suppressing the emission of carbon dioxide.

Techniques for suppressing carbon dioxide emission include energy saving technology for reducing carbon dioxide emission, technology for separating and recovering carbon dioxide, technology for using or immobilizing carbon dioxide, and renewable energy technology that does not emit carbon dioxide.

As a technique for separating and recovering carbon dioxide, absorption, adsorption, membrane separation, deep cooling, and the like have been proposed. Absorption method is a method of removing carbon dioxide by using an absorbent, it can be easily applied to most industrial and power plants because of its high efficiency and stability, easy to process large gas and suitable for low concentration gas separation.

Conventional acid gas separation recovery process is to contact the exhaust gas with the absorbent in the absorption tower so that the acid gas of the exhaust gas is absorbed into the absorbent. At this time, using the washing water or make-up water to prevent the absorption of the absorbent or vapor.

The absorbent absorbing acid gas from the absorption tower is injected into the upper part of the stripping column via a heat exchanger. The stripping column uses the thermal energy supplied through the reboiler to remove the acid gas chemically bound to the absorbent to regenerate the absorbent. The mixed gas of stripped acidic gas and steam is phase separated in the reflex drum. The separated steam is recovered as condensate and fed back to the stripping tower, where the acid gas is converted to storage or other useful high value chemicals through acid gas recovery and treatment. The absorbent regenerated in the stripping tower is transferred to the absorption tower after the temperature is lowered through the heat exchanger.

In the conventional acid gas separation recovery process, the acid gas concentration of the outlet gas of the absorption tower can be reduced by the chemical reaction of the absorbent, but in order to keep the acid gas concentration of the outlet gas low, it is necessary to increase the height of the absorption tower and the stripping column. There is this.

In addition, in the conventional acid gas separation recovery process, energy efficiency is lowered by indirectly supplying thermal energy for regenerating the absorbent in the stripping column through the reboiler. Therefore, since most of the total cost of the acid gas separation recovery process is used to provide heat energy for absorbent regeneration, it is required to develop a new acid gas separation recovery process that can reduce the renewable energy.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to provide an acid gas separation and recovery apparatus using steam as condensate and make-up water as an energy source for regenerating an absorbent.

An acid gas separation and recovery apparatus of the present invention for achieving the above object comprises an absorption tower for producing an acid gas saturated absorbent by countercurrently contacting the absorbent with the exhaust gas containing the acid gas; A stripping column for separating the acid gas saturated absorbent into an acid gas and an absorbent by using thermal energy to regenerate the absorbent; A steam generator for generating steam by vaporizing supplemental water supplied to the absorption tower; And a nozzle installed in the stripping column and spraying the steam to counter-currently contact the acidic gas saturated absorbent and the steam to provide the thermal energy to the stripping column.

The steam generator is supplied with condensed water condensed with the discharged water vapor discharged from the stripping column to vaporize the condensed water to generate the steam.

The acidic gas separation and recovery apparatus of the present invention is a reboiler for directly supplying the regenerated absorbent provided from the stripping tower to the stripping tower by directly contacting the steam absorber provided from the steam generator to provide the thermal energy to the stripping tower. It further includes.

The acid gas includes at least one of carbon dioxide (CO ₂ ), hydrogen sulfide (H ₂ S), sulfur dioxide (SO ₂ ), nitrogen dioxide (NO ₂ ) and carbonyl sulfide (COS).

The make-up water may be provided to adjust the resin of water required in the process of producing the acid gas saturated absorbent in the absorption tower, and may also be supplied to the steam generator through a make-up water supply line connecting the third pump and the steam generator. Can be.

In the acid gas separation and recovery apparatus of the present invention, since the condensed water and the supplemental water can be vaporized and sprayed directly to the stripping tower through the nozzle to supply the absorbent regeneration heat energy, the absorber regeneration heat energy using the indirect heat exchanger in the conventional stripping column. It is effective to supply the absorbent regeneration heat energy more efficiently than when supplying.

 1 is a process chart of the acid gas separation recovery apparatus according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

1 is a process chart of the acid gas separation recovery apparatus according to an embodiment of the present invention.

Referring to FIG. 1, the acidic gas separation and recovery apparatus includes an absorption tower 201, a stripping column 203, a reboiler 204, a steam generator 220, a reflux drum 206, and a supplemental water supply line 230. , The condensed water supply line 232, the first to third heat exchangers 211, 212, and 213, and the first to fifth pumps 251, 252, 253, 254, and 255.

The absorption tower 201 is supplied with the exhaust gas 101 and the absorbent. The exhaust gas 101 is a chemical process gas or a combustion vessel including at least one acid gas of carbon dioxide (CO ₂ ), hydrogen sulfide (H ₂ S), sulfur dioxide (SO ₂ ), nitrogen dioxide (NO ₂ ), and carbonyl sulfide (COS). It may be gas. In order to overcome the pressure drop generated in the absorption tower 201, the exhaust gas 101 is preferably supplied to the absorption tower 201 while being cooled by the second pump 252 and the third heat exchanger 213. .

The absorbent 102 may be used alone or in combination with an amine-based, amino acid salt, inorganic salt solution, ammonia water, and the like, and is not particularly limited. At this time, the absorbent is preferably used as an aqueous solution in the range of 1 to 50 volume fractions.

In the absorption tower 201, the absorbent 102 and the exhaust gas 101 are in direct contact with each other. The absorbent 102 absorbs the acid gas contained in the exhaust gas 101 to produce the acid gas saturated absorbent 105. The acid gas saturated absorbent 105 is injected into the stripping column 203 while being preheated by the fourth pump 254 and the first heat exchanger 211. Off-gas 101, absorbent 102 and the unreacted nitrogen (N ₂₎ of oxygen (O ₂₎ such as non-reacted gas (110), a to be supplied to the upper absorber 201 by a first pump (251) Absorption 102 or vapor is prevented from splashing by the replenishment water 104 supplied to the upper part of the absorption tower 201 by the washing water 103 or the third pump 253, and then the absorption tower 201 ) Is discharged through the top. Replenishment water 104 is water for matching the resin of the water required in the process of the absorption tower 201, the steam generator through the replenishment water supply line 230 connecting the third pump 253 and the steam generator 220 220 may be supplied.

Filler may be used in the absorption tower 201 to improve the contact efficiency of the liquid absorbent 102 and the gaseous exhaust gas 101. The operating temperature of the absorption tower 201 may vary depending on the type of absorbent. For example, the operating temperature of the absorption tower 201 may be maintained in a range of 40 ° C to 60 ° C.

The stripping column 203 separates the acidic gas saturated absorbent 105 into the acidic gas 107 and the absorbent 102 by using thermal energy provided by the steam generator 220 or the reboiler 204. The acid gas saturated absorbent 105 injected into the stripping column 203 is moved by the bottom of the stripping column 203 and is heated by the thermal energy of water vapor injected through the nozzle 208 installed at the bottom of the stripping column 203. The acid gas 107 is stripped off and the absorbent 102 is regenerated.

The mixed gas 106 mixed with the acid gas 107 and the discharged water vapor is phase-separated into the condensate 108 and the acid gas 107 through the second heat exchanger 212 and the reflux drum 206. The acid gas 107 is transferred to a recovery process or treatment process and used according to storage or use, and the condensate 108 is steam along the condensed water supply line 232 connecting the reflux drum 206 and the steam generator 220. Supplied to the generator 220. At this time, some of the condensate 108 may be transferred to the upper portion of the stripping tower 203 to clean the suspended matter present in the mixed gas 106 rising to the upper portion of the stripping tower 203. The regenerated absorbent 102 is fed to the reboiler 204.

The steam generator 220 is a heat energy source for supplying absorbent renewable energy by vaporizing the supplemental water 104 and the condensate 108 and directly supplying the stripping column 203 or the reboiler 204. The steam generator 220 is connected to the third pump 253 and the replenishment water supply line 230, and is connected to the reflux drum 206 and the condensate water supply line 232, and the stripping tower 203 and the reboiler ( 204 and the steam supply line 234 is connected. The end of the steam supply line 234 connected to the stripping tower 203 is connected to the nozzle 208 installed at the bottom of the stripping tower 203.

The reboiler 204 exchanges heat by directly contacting the absorbent 102 regenerated in the tower column 203 with water vapor provided through the water vapor supply line 234. The heat-exchanged absorbent 102 is again supplied to the lower portion of the stripping column 203 or supplied to the upper portion of the absorption tower 210 through the first heat exchanger 211 by the fifth pump 255. The reboiler 204 may be supplied with a thermal energy source 110 that supplies absorbent renewable energy to the stripping column 203 indirectly through the reboiler 204.

Acid gas separation and recovery apparatus according to an embodiment of the present invention has a configuration in which the condensed water and the replenishment water vaporized directly counter-current contact with the acid gas saturated absorbent 105 through the nozzle 208 under the stripping column 203. Therefore, the absorbent renewable energy can be efficiently supplied to the stripping column 203.

In addition, the reboiler 204 of the acid gas separation and recovery apparatus according to an embodiment of the present invention exchanges the vaporized condensed water and supplemental water with the absorbent 102 to supply the absorbent to the stripping column 203 to transfer heat energy. It can be used as a medium.

≪ Example 1 >

Using a 30 wt% monoethanolamine as an absorbent, a combustion flue gas adjusted to 40 ° C. containing 10 wt% of carbon dioxide as an acidic gas was introduced into the absorption tower 201 at a flow rate of 2.0 m ³ . The circulation amount of the absorbent was 100 ml / min, and the temperature of the absorbent introduced into the absorption tower 201 was 40 ° C. The total amount of condensed water refluxed was made into a saturated steam at 150 ° C. using a steam generator 220 to be sprayed through the nozzle 208 at the bottom of the stripping column 203 to be brought into contact with the absorbing liquid descending to countercurrent. The carbon dioxide (CO ₂ ) concentration of the exhaust gas before entering the absorption tower 201 and passing through the absorption tower 201 was measured using a gas analyzer, and the removal rate was calculated in the absorption tower 201. The results are shown in Table 1 below. .

<Example 2>

The removal rate obtained by performing the same method as Example 1 using the regenerated absorbent submerged in the reboiler 204 as the injection position of the water vapor refluxed in Example 1 is shown in Table 1.

&Lt; Comparative Example 1 &

Except that the condensate refluxed in Example 1 is injected into the upper part of the stripping column 203 as in the conventional process, the removal rate obtained by performing the same method as in Example 1 is shown in Table 1.

Example / Comparative Example Injection reflux state Injection position CO ₂ Removal rate Example 1 Gas (Water Vapor) Bottom of stripping tower 95.2% Example 2 Gas (Water Vapor) Reboiler absorbent 94.9% Comparative Example 1 Liquid (water) Top of stripping tower 90.1%

Referring to Table 1, in the case of Examples 1 and 2 it can be seen that the removal efficiency of the carbon dioxide which is acidic gas is higher than in Comparative Example 1, in particular when the direct injection of water vapor from the bottom of the stripping column is improved carbon dioxide removal efficiency I could confirm that. In view of these results, when the stripping process developed in the present invention is applied, the height of the stripping column and the absorption tower can be reduced or the amount of renewable energy used can be reduced as the CO ₂ removal efficiency is increased.

Although the detailed description of the present invention described above has been described with reference to a preferred embodiment of the present invention, a person skilled in the art without departing from the spirit and scope of the present invention described in the claims to be described later It will be understood that various modifications and variations can be made in the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

201: absorption tower 203: stripping tower
204: Reboiler 206: Reflux Drum
211, 212, and 213: first to third heat exchangers
220: steam generator 230: replenishment water supply line
232: condensate supply line
251, 252, 253, 254, 255: first to fifth pumps

Claims (5)

An absorption tower in which the absorbent is countercurrently contacted with the exhaust gas including the acid gas to generate an acid gas saturated absorbent;
A stripping column for separating the acid gas saturated absorbent into an acid gas and an absorbent by using thermal energy to regenerate the absorbent;
A pump for supplying supplemental water to the absorption tower;
Replenishment water supply line connected to the pump;
A steam generator connected to the supplemental water supply line to generate steam by vaporizing the supplemented water; And
And a nozzle installed in the stripping column and spraying the steam to provide the thermal energy to the stripping column such that the acid gas saturated absorbent and the water vapor are in countercurrent contact.
According to claim 1, wherein the steam generator,
And condensed water supplied with condensed water vapor discharged from the stripping column to vaporize the condensed water to generate the water vapor.
The method according to claim 1 or 2,
The acid gas separation and recovery apparatus further includes a reboiler for directly supplying the regenerated absorbent provided from the stripping column to the stripping column in direct contact with the water vapor provided from the steam generator to supply the thermal energy to the stripping column. .
The method of claim 1, wherein the acid gas
Acid gas separation recovery apparatus comprising at least one of carbon dioxide (CO ₂ ), hydrogen sulfide (H ₂ S), sulfur dioxide (SO ₂ ), nitrogen dioxide (NO ₂ ) and carbonyl sulfide (COS).
The method of claim 1, wherein the replenishment water,
Acid gas separation recovery device characterized in that it is provided to match the resin of the water required in the process of producing the acid gas saturated absorbent in the absorption tower.

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