KR20160016144A - System for collecting acid gas and method for collecting the same - Google Patents

Abstract

The present invention relates to an acid gas capturing system and a capturing method thereof. According to the present invention, disclosed is an acid gas capturing system which comprises: an absorption tower absorbing acid gas in exhaust gas by means of an absorbent; a desorption tower receiving the absorbent which has absorbed the acid gas from the absorption tower and separating the acid gas and the absorbent under a predetermined temperature and pressure; a reboiler receiving the absorbent, which is separated from the acid gas, from the absorption tower and supplying the absorbent after applying steam at a specific temperature onto the supplied absorbent; a first supply line receiving, from the desorption tower, the absorbent separated from the acid gas from a first position to a second position; and a heat supplier supplying heat to the desorption tower by allowing the absorbent supplied through a circulation line to pass through an interior of the desorption tower. According to the present invention, the acid gas capturing system can minimize consumption of renewable energy which is conventionally consumed in a capturing process by recycling the renewable energy in the acid gas capturing process.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an acid gas collecting system and a collecting method thereof,

The present invention relates to an acid gas collection system and a collection method thereof.

Recently, efforts to collect and store greenhouse gases, the causative substance of global warming, have been racing internationally. In particular, many technologies have been developed to reduce carbon dioxide, which is an acid gas in greenhouse gases, such as chemical absorption, adsorption, membrane separation, and deep sea cooling.

The chemical absorption method using the absorbent used for removing carbon dioxide, which is an acid gas generated in a combustion plant such as a thermal power plant, has been studied with high efficiency and stable technology. Amine-based capture process for trapping carbon dioxide is a kind of chemical absorption technology. It is a technology that has been technically reliable as applied in the reforming process during the petrochemical process. However, it needs to be improved in order to apply it to the combustion exhaust gas instead of the petrochemical process gas. Separation technology.

Typical carbon dioxide capture systems are broadly classified into absorption towers, demoulding towers and reboilers as disclosed in Korean Patent Laid-open Nos. 10-2014-004299, 10-2014-003826 and 10-2013-0023484 Includes boilers. Such a conventional carbon dioxide capture system consumes a large amount of energy for carbon dioxide absorption and regeneration of the absorbent in the stripping process. Recently, development of a process related to an absorbent for reducing renewable energy has been required. In particular, there is a demand for a method for improving the collection efficiency of the most economical carbon dioxide by optimizing the apparatus and flow of the removal process.

Korean Patent Publication No. 10-2014-004299 " Korean Patent Publication No. 10-2014-003826 " Korean Patent Publication No. 10-2013-0023484 "

The present invention can minimize the amount of renewable energy consumed in the collection process by recycling the regenerated energy in the process of collecting the acid gas and prevent the phase separation of the moving absorbent to remove the acid gas during the heat exchange of the absorbent And a method of collecting the acid gas.

An acid gas collection system according to an embodiment of the present invention includes an absorption tower for absorbing an acid gas of an exhaust gas using an absorbent; A stripping tower to which the absorbent having absorbed the acid gas is supplied from the absorption tower and which separates the acid gas and the absorbent at a predetermined temperature and pressure; A reboiler supplied with the absorbent separated from the deodorizing tower with the acid gas and supplying steam to the deodorizer with steam at a predetermined temperature; A first supply line for supplying an absorbent separated from the acid gas to the second position from the first position of the de-molding tower through the de-stacking tower; And a heat supplier for supplying heat to the demolition tower through the inside of the demolition tower, through which the absorbent supplied through the circulation line is supplied.

A second supply line for supplying the absorbent absorbed with the acid gas from the absorption tower to the deactivation tower and a third supply line for supplying the absorbent separated from the acid tank to the absorption tower in the de- And a heat exchanger installed in the heat exchanger.

Further, the third supply line may supply the absorbent discharged from the heat supplier to the absorption tower.

In addition, the heat exchanger can raise the temperature of the absorbent supplied to the deodorizer using the temperature of the absorbent discharged from the heat supplier.

In addition, the first supply line may be installed such that the absorbent separated from the acid gas is supplied from the lower part of the demolition tower to the middle part.

In addition, the first position of the first supply line may be adjacent to the position where the absorbent is supplied from the reboiler in the deodorizing tower.

An acidic gas capturing method according to an embodiment of the present invention includes an acidic gas absorbing step of absorbing an acidic gas of an exhaust gas using an absorbent; An acidic gas separation step of separating the acid gas and the absorbent by applying a predetermined temperature; A first heat supply step of recovering the absorbent separated from the acid gas, supplying steam to the recovered absorbent at a predetermined temperature for the acid gas separation step; And a second heat supply step of reusing the absorbent separated from the acid gas through the acid gas separation step for the heat supply of the acid gas separation step.

The method may further include a heat exchange step of raising the temperature of the absorbent absorbed by the acid gas through the acid gas absorption step using the absorbent used through the second heat supply step.

A first supply step of supplying the absorbent heated through the heat exchange step for the acid gas separation step; And a second supplying step of supplying the absorbent that has been thermally heated through the heat exchange step for the acid gas absorbing step.

The second heat supply step may supply the absorbent separated from the acid gas through the acid gas separation step to a position where heat for separating reaction between the acid gas and the absorbent can be applied.

According to the present invention, it is possible to minimize the amount of the regenerated energy consumed in the collection process by recycling the regenerated energy in the process of collecting the acid gas, and the phase separation phenomenon of the moving absorbent for removing the acid gas during the heat exchange of the absorbent It is possible to provide an acid gas collecting system capable of preventing the above-mentioned problems and a method of collecting the same.

1 is a block diagram showing the configuration of an acid gas collection system according to an embodiment of the present invention.
2 is a flowchart illustrating an acid gas trapping method according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily carry out the present invention.

1 is a block diagram showing the configuration of an acid gas collection system according to an embodiment of the present invention.

1, an acid gas collection system 1000 according to an embodiment of the present invention includes an absorption tower 100, a stripping tower 200, a reboiler 300, a first supply line SL1, 400). In addition, the acid gas collection system 1000 may further include a heat exchanger 500, a cooler 600, a cleaner 700, a condenser 800, and a gas-liquid separator 900.

The acid gas collecting system 1000 configured as described above is capable of absorbing the absorbent (phosphorous amine) A2 and the flue gas G1 at a temperature of about 40 to 60 캜 in the absorption tower 100 to be contained in the flue gas G1 (For example, carbon dioxide). At this time, the acid gas in the flue gas G1 is chemically bonded to the absorbent A2 by contacting with the absorbent A2, and the flue gas G2 from which the acidic gas has been removed prevents the absorbent A2 or steam from being spoken And is discharged from the absorption tower 100 after passing through the washer 700. The absorbent (rich amine) A1 in which the acid gas has been collected is injected into the upper end of the stripping tower 200 through the second supply line SL2. The absorbent according to an embodiment of the present invention may use any one of an amine type, an amino acid salt, a mineral salt solution and an aqueous ammonia, or a mixture of two or more thereof.

(Rich amine) A1 to be transferred to the deodorizer 200 through the second supply line SL2 and a third supply line SL3 discharged from the heat supplier 400 of the deodorizer 200, Absorbing agent (phosphorus amine) A2 transferred to the absorber 100 through the heat exchanger 500 is heat-exchanged with each other through the heat exchanger 500. At this time, the absorbent (rich amine) A1 conveyed through the second supply line SL2 receives the heat of the high temperature absorber (lean amine) A2 conveyed through the third supply line SL3, (Lean amine) A2 supplied to the absorption tower 100 through the third supply line SL3 flows through the second supply line SL2 to the stripping tower 100 via the second supply line SL2, (Rich amine) A1 supplied to the adsorbent 200, the temperature is lowered. The absorbent A2 absorbed through the heat exchanger 500 is supplied to the absorber 100 to absorb the acid gas of the flue gas G1 and the absorbent A1 absorbs the heated absorbent A1 Is supplied to the stripping tower 200 to perform an acid gas removal process.

The absorbent (rich amine) A1 supplied to the stripping tower 200 is heated by the steam supply of the reboiler 300 and heated to a predetermined temperature (about 110 to 140 ° C) Can be separated.

The sorbent (lean amine) separated from the acid gas through the stripping tower 200 is supplied to the reboiler 300 through the fourth supply line SL4, and the reboiler 300 is connected to the deodorizer 200 And the supplied high-temperature absorbent (lean amine) is supplied to the deodorizing tower (not shown) through the fifth supply line SL5, 200 as the primary thermal energy. A part of the high temperature absorbent (lean amine) separated from the acid gas through the stripping tower 200 is supplied to the heat supply unit 400 installed in the demounting tower 200 through the first supply line SL1 . The first supply line SL1 is installed so as to connect the middle portion P2 at the lower end portion P1 of the demounting tower 200. The heat supply device 400 is installed as a reheating medium of the demounting tower 200 , And is connected to the first supply line (SL1) and passes through an intermediate part of the inside of the demounting tower (200). Here, the middle part of the inside of the stripping tower 200 may refer to a position where a separation reaction of an acid gas and an absorbent (lean amine) takes place. In this way, the heat supplier 400 supplies the secondary thermal energy of the stripping tower 200 using an absorbent (lean amine) supplied through the first supply line SL1.

The lower end portion P1 of the stripping tower 200 through which the absorbent (lean amine) is discharged through the first supply line SL1 is discharged from the reboiler 300 through a high temperature (about 110 to 140 ° C) (Lean amine). Therefore, a high-temperature absorbent (lean amine) can be supplied to the heat supplier 400 through the first supply line SL1.

In order to raise the temperature of the deodorizer 200 to a high temperature absorbent (lean amine) supplied through the reboiler 300 using the first supply line SL1 and the heat supplier 400, By recycling, the steam used in the reboiler 300 can be reduced by about 5 to 15%. Therefore, by reducing the amount of the regenerated energy in the process of collecting the acid gas, the cost required for the renewable energy, which occupies the largest portion in the separation and recovery process of the acid gas, can be reduced and the height of the demolition tower 200 can be designed smaller The initial investment cost can be reduced.

The absorption agent (lean amine) A2 used for the reheating of the stripping tower 200 through the heat supplier 400 and the absorbent (rich amine) transferred from the absorption tower 100 to the stripping tower 200, (A1) is heat exchanged through the heat exchanger (500). Conventionally, when the heat exchanging between the lean amine and the rich amine causes the temperature of the rich amine to rise above 100 ° C due to the high temperature lean amine, the rich amine is phase-separated in the pipe. However, as in the embodiment of the present invention, when the amine A2 is used for reheating the deodorizer 200, the temperature of the amine A2 is less than 105 ° C, (About 98 ° C or lower) of the rich amine (A1) that has passed through the high-boiling point water (500) is also less than the conventional one.

The mixed gas G3 of the acid gas and water vapor removed from the absorbent through the stripping tower 200 is recovered through the condenser 800 connected to the upper end of the stripping tower 200, Liquid separating tank 900, and is circulated to the demolition tower 200.

2 is a flowchart illustrating an acid gas trapping method according to an embodiment of the present invention.

Referring to FIG. 2, an acid gas absorption method (S2000) according to an embodiment of the present invention includes an acidic gas absorption step (S2100) of absorbing an acidic gas of an exhaust gas using an absorbent, A first heat supply step S2400 for recovering the acid gas and the absorbent separated from the acid gas, supplying steam to the recovered absorbent at a predetermined temperature for the acid gas separation step S2200, And a second heat supply step (S2400) for reusing the absorbent separated from the acid gas through the acid gas separation step (S2200) for the heat supply of the acid gas separation step (S2200).

In addition, the acid gas capturing method (S2000) according to the embodiment of the present invention may be configured such that the acid gas is absorbed through the acid gas absorbing step (S2100) using the absorbent used in the second heat supplying step (S2400) (S2500) for raising the temperature of the absorbent, a first supplying step for supplying the absorbent heated through the heat exchanging step (S2500) for the acidic gas separating step (S2200), and a heat exchanging step And a second supply step of supplying the absorbent that has been thermally heated through the first adsorption step (S2100). In the second heat supply step (S2400), the absorbent separated from the acidic gas through the acidic gas separation step (S2200) may be supplied to a position where heat for separating reaction between the acidic gas and the absorbent can be applied.

The method of collecting the acid gas according to the embodiment of the present invention is the same as that of the above-described acid gas collecting system, and thus a detailed description thereof will be omitted.

<Experimental Example>

Using a 30 wt% monoethanolamine as a sorbent, a combustion exhaust gas containing carbon dioxide of 15 vol%, which was controlled at 40 ° C, was introduced into the absorber 100 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 put into the absorption tower 100 was 40 ° C. A storage tank 900 for temporarily storing the absorbent heated by the exothermic reaction of the absorbent and the carbon dioxide in the absorption tower 100 to perform vapor-liquid separation, and an apparatus 600 for exchanging heat with the absorbent at a high temperature coming from the stripping tower 200 Thereby supplying the reboiler 300 with an absorbent. The absorber (lean amine) coming from the lower portion of the reboiler 300 is installed to reheat the demolition tower 200. The carbon dioxide concentration of the exhaust gas before entering the absorption tower 100 and the exhaust gas passing through the absorption tower 100 is measured using a gas analyzer to calculate the reboiler thermal capacity per ton of carbon dioxide captured at a carbon dioxide removal rate of 90% The results are shown in Table 1 as follows.

<Comparative Example>

In the above experimental example, the absorption tower 100 is heat-exchanged only with the high-temperature absorption liquid from the stripping tower 200, the absorbent passes through the stripping tower 200 and the reboiler 300, 1.3 times, and the reboiler thermal capacity per ton of carbon dioxide collected at 90% of the carbon dioxide removal rate obtained in the same manner as in the above example except that steam condensate is not reused is shown in Table 1 as follows .

Demolition tower
Whether reheating Rich amine
Heat exchange medium Cold singer
Circulation amount
(cc / min) Reboiler
Heat usage
(GJ / ton-CO ₂ ) Experimental Example Reheating 1) Reheating of the demolding tower of high temperature linamine
2) Carbon Dioxide Removal Absorbent 500 3.65 Comparative Example No reheating 1) Carbon Dioxide Removal Absorbent (Linamine) 500 3.85

In the case of the above experimental example, it can be confirmed that the thermal capacity of the reboiler is less than that of the comparative example in collecting the same carbon dioxide at the same carbon dioxide removal efficiency (90%). As a result, when the absorption and removal processes according to the present invention are applied based on the same carbon dioxide removal rate, the amount of steam used in the reboiler can be drastically reduced and the initial investment cost can also be reduced have.

Although the present invention has been described with reference to the specific embodiments for carrying out the invention, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention.

1000: Acid gas collection system
100: Absorption tower
200: Removal tower
300: reboiler
400: heat source
500: Heat exchanger
600: cooler
700: Washer
800: condenser
900: gas-liquid separation tank
SL1: first supply line
SL2: second supply line
SL3: Third supply line
SL4: fourth supply line
SL5: fifth supply line
SSL: Steam supply line

Claims (10)

An absorption tower for absorbing the acid gas of the flue gas using an absorbent;
A stripping tower to which the absorbent having absorbed the acid gas is supplied from the absorption tower and which separates the acid gas and the absorbent at a predetermined temperature and pressure;
A reboiler supplied with the absorbent separated from the deodorizing tower with the acid gas and supplying steam to the deodorizer with steam at a predetermined temperature;
A first supply line for supplying an absorbent separated from the acid gas to the second position from the first position of the de-molding tower through the de-stacking tower; And
And a heat supplier for supplying heat to the deodorizer through the inside of the deodorizer so that the absorbent supplied through the circulation line passes through the deodorizer. The method according to claim 1,
A second supply line for supplying the absorbent absorbed with the acid gas from the absorption tower to the deactivation tower and a third supply line for supplying the absorbent separated from the acid gas to the absorption tower in the de- Further comprising a heat exchanger. 3. The method of claim 2,
And the third supply line supplies the absorbent discharged from the heat supplier to the absorption tower. The method according to claim 1,
Wherein the heat exchanger raises the temperature of the absorbent supplied to the deodorizer by using the temperature of the absorbent discharged from the heat supplier. The method according to claim 1,
Wherein the first supply line is installed such that the absorbent separated from the acid gas is supplied from the lower part of the demolition tower to the middle part. The method according to claim 1,
Wherein the first position of the first supply line is adjacent to a location where the absorbent is fed from the reboiler in the stripping tower. An acid gas absorption step of absorbing the acid gas of the flue gas using an absorbent;
An acidic gas separation step of separating the acid gas and the absorbent by applying a predetermined temperature;
A first heat supply step of recovering the absorbent separated from the acid gas, supplying steam to the recovered absorbent at a predetermined temperature for the acid gas separation step; And
And a second heat supply step of reusing the absorbent separated from the acid gas through the acid gas separation step for the heat supply of the acid gas separation step. 8. The method of claim 7,
Further comprising a heat exchange step of raising the temperature of the absorbent absorbed by the acid gas through the acid gas absorption step using the absorbent used through the second heat supply step. 9. The method of claim 8,
A first supply step of supplying the absorbent heated through the heat exchange step for the acidic gas separation step; And
And a second supply step of supplying the absorbent that has been thermally heated through the heat exchange step for the acid gas absorption step. 8. The method of claim 7,
Wherein the second heat supply step supplies the absorbent separated from the acid gas through the acid gas separation step to a position where heat for separating reaction between the acid gas and the absorbent can be applied. Collection method.

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