BE1030055B1 - Carbon Dioxide Separation Device - Google Patents

Abstract

The present invention relates to a carbon dioxide separation device 10, the carbon dioxide separation device 10 having an absorption device 20 and a desorption device 30, the absorption device 20 having a gas inlet 21 for the gas to be cleaned and a gas outlet 22 for the cleaned gas, the absorption device 20 has an absorption solvent inlet 23 and a solution outlet 24, the desorption device 30 having at least a first solution inlet 31, an absorption solvent outlet 32, a warm solvent inlet 33 and a carbon dioxide outlet 34, the solution outlet 24 being connected to the first solution inlet 31 via a first solution connection 40, the first solution connection 40 having a first heat exchanger 41, the absorption solvent outlet 32 being connected to the absorption solvent inlet 23 via an absorption solvent connection 50, the absorption solvent connection 50 having the first heat exchanger 41 such that the heat of the solvent stream is transferred to the solution stream, the absorption solvent connection 50 has a branch 51 to a warm solvent connection 52 , the warm solvent connection 52 being connected to the warm solvent inlet 33 , the warm solvent connection having a second heat exchanger 53 .

Description

1 BE2021/6008

Carbon Dioxide Separation Device

The invention relates to a device for separating carbon dioxide from gases, in particular from exhaust gases.

In order to reduce man-made climate change, it is increasingly avoided

release carbon dioxide into the atmosphere. Rather, an attempt is made to

Separating carbon dioxide and either converting it afterwards or dumping it. A typical method for this is to scrub exhaust gases at about 25°C to 50°C with a basic solution, for example an amine solution. This amine solution acts as a solvent in which the carbon dioxide dissolves. The one containing the carbon dioxide

The solution is then heated and the carbon dioxide is converted back into the gas phase in a desorption step. This recovers the solvent and also produces a pure carbon dioxide gas stream. The carbon dioxide gas stream can then, for example and purely by way of example, be deposited or fed to a methanol synthesis.

WO 2010/086 039 A1 discloses a method and a device for separating carbon dioxide from an exhaust gas from a fossil-fired power plant.

From CN111203086A is a low CO2 separation system

Energy consumption and low emissions known.

WO 2014/077 919 A1 discloses a device and a method for removing acidic gases from a gas stream and regenerating the absorbing solution.

From US 2017 / 0197175 A1 is an energy-efficient process for the extraction of acidic

Gas from a gas stream known.

From WO 2013/0013 749 A1 is a heat recovery in absorption and

known desorption processes.

WO 2019 / 232 626 A1 describes a CO2 separation after combustion with a

heat recovery known.

2 BE2021/6008

From US20217/0220771A1 one is downstream of the incineration

Carbon dioxide separation known with a heat recovery.

From the CN208786105U is a carbon dioxide separator with a

heat recovery known.

A carbon dioxide absorber is known from US 2014/0127119 A1.

From US Pat. No. 5,145,658 the recovery of the heat of reaction is alkaline

Washing solution known for removing acid gases.

The removal of carbon dioxide from a gas mixture is known from US Pat. No. 3,563,696 A.

From WO 2004/080 573 A1 is the regeneration of an aqueous solution from a

Gas absorption process known.

A method for removing carbon dioxide from a gas is known from US 2014/0374105 A1.

What all systems for separating CO have in common is that energy must be supplied to release the CO2 from the solution again. For this purpose, heat is used at a high and thus comparatively valuable level.

The object of the invention is to provide a carbon dioxide separation device in which the overall process of absorption and desorption is energetically optimized.

This task is solved by the carbon dioxide separation device with the

Claim 1 specified features. Advantageous developments result from the dependent claims, the following description and the drawings.

The carbon dioxide separation device according to the invention has a

Absorption device and a desorption device. In the

The gas to be cleaned of carbon dioxide is introduced into the absorption device and the carbon dioxide is converted from the gas phase into the liquid phase by contact with a solvent, usually an amine solution. A solution is formed from the solvent with the carbon dioxide dissolved therein, possibly bound. This solution is transferred to the desorption device where the carbon dioxide is stripped out of the solution, thereby recovering the solvent and recirculating it back into the system

Absorption device is transferred. Likewise, a carbon dioxide gas stream is obtained, which can be supplied for further use. This basic principle is already used in a large number of variations.

The absorption device has a gas inlet for the gas to be cleaned and a

Gas outlet for the cleaned gas. The gas to be cleaned can, for example

Waste gas from burning fossil fuels. The cleaned gas would then mostly be mainly nitrogen with a small remainder of carbon dioxide and possibly a greatly reduced proportion of carbon dioxide as a result of the combustion process

Oxygen. The cleaned gas can then be released into the atmosphere, for example, without releasing large amounts of carbon dioxide as a greenhouse gas. The

Absorption device usually has one or more mass transfer elements arranged between the gas inlet and the absorption solvent inlet.

The mass transfer elements serve to bring the liquid and the gaseous phase into better contact, in particular also to increase the surface area of the liquid phase.

Such mass transfer elements are known to the person skilled in the art and can be, for example, bubble-cap trays, packing or structured packing

The absorption device further includes an absorption solvent inlet and a

solution outlet. The absorption solvent inlet is usually at the top of the

Absorption device arranged, the solution outlet at the bottom of the

absorption device. Accordingly, the gas inlet is usually at the bottom and the

Gas outlet located on top so that gas and solvent flow countercurrently through the

Flow absorption device.

The desorption device has at least a first solution inlet, a

absorption solvent outlet, a warm solvent inlet and a carbon dioxide outlet. The solution outlet of the absorber is connected to the first solution inlet

4 BE2021/6008 of the desorption device via a first solution connection. The first

Solution connection has a first heat exchanger. This will make the

Solution stream, which flows through the first solution connection, heated so that in the

Desorption device, the carbon dioxide present in the solution can be released again. The absorption solvent outlet of the desorption device is connected to the

Absorption solvent inlet of the absorption device via a

Connected absorption solvent compound. The solvent depleted of carbon dioxide in the desorption device flows back to the absorption solvent connection via the absorption solvent connection

absorption device. The absorbent solvent compound also has the first

heat exchanger on. As a result, the heat of the solvent stream in the

Transfer absorption solvent compound to the solution stream. The

Absorption solvent connection has a branch to a warm solvent connection. So it is branched off a partial flow of the solvent flow and into the

Warm solvent connection led. The warm solvent connection is with the

Connected to warm solvent inlet. The warm solvent compound has a second

heat exchanger on. As a result, additional energy can be introduced into the entire system. The desorption device usually has one or more

Mass transfer elements, which are arranged above and below the first solution inlet. The mass transfer elements serve to bring the liquid and the gaseous phase into better contact, in particular also to increase the surface area of the liquid phase. Such mass transfer elements are known to those skilled in the art and can, for example, be bubble-cap trays, random packings or structured packing.

According to the invention branches between the absorption device and the first

Heat exchanger of the first solution compound from a third solution compound. The third solution connection is fluidly connected to the first solution connection after the first heat exchanger or absorber at the end where the solution stream exits the third solution connection again. The third

Solution compound has a fourth heat exchanger in which the solution stream of the third solution compound is heated. The fourth heat exchanger and the

Gas inlets are connected via a gas connection so that the gas to be cleaned is passed through the fourth heat exchanger before the gas to be cleaned enters the

Absorption device is performed. Usually, the gas to be cleaned with a

Temperature between 100 ° C and 200 ° C, for example 150 ° C, provided, according to how it is obtained from the preliminary processes. In the absorption device are

Temperatures of 30°C to 40°C are common, a heat exchanger is usually required for cooling. However, the heat that occurs here can often no longer be used, since it occurs at a very low level. Through the direct

Heat transfer can be used to transfer the energy directly to the solution stream, which is brought to, for example, 100° C. to 110° C. and thus to the temperature level of the desoption device. As a result, the energy supplied to the second heat exchanger, which comes from a higher-value energy source, usually steam, can be saved at least in part.

In a further embodiment of the invention, the first solution connection has an evaporation device downstream of the first heat exchanger in terms of flow. The evaporation device, also known as the pressure expansion tank, is used to allow the solution of the solution stream heated in the first heat exchanger to expand and therefore partially evaporate. In the evaporation device, the liquid phase of the solution stream is thus separated from the gaseous phase of the

solution stream separately. The liquid phase is led into the desorption device through the first solution connection. The desorption device further has a

Steam inlet and the evaporation device has a steam outlet. The

Vapor outlet of the vaporization device and the vapor inlet of the

Desorption are for the conversion of the gaseous phase with a

Connected gas solution compound. The steam inlet at the bottom is particularly preferred

Arranged area of the desorption device. This will increase the energetic

Management of the overall process optimized.

In another embodiment of the invention, the third solution compound is am

End, where the solution stream exits again from the third solution connection, with the

Evaporation device connected. In this way, as in the case of the heated solution stream of the first solution compound, expansion can take place here and the gas phase can be separated from the liquid phase.

6 BE2021/6008

In a further embodiment of the invention, the gas connection has a

raw gas cleaning. Particular and preferred is the raw gas cleaning

Trained removal of sulfur oxides.

In a further embodiment of the invention branches between the

Absorption device and the first heat exchanger of the first solution compound from a second solution compound. The second solution connection leads directly into the

Head of the desorption device. Direct in this context means without one

heat exchanger or the like. If necessary, a (flow control) valve can be arranged here. The solution loaded with carbon dioxide is thus itself used to cool the gas stream exiting the desorption device. As a result, the remains of the first heat exchanger and the second heat exchanger in the

Desorption device supplied heat in the desorption device and in the solvent and is not released to a cooling medium.

In a further embodiment of the invention branches between the

Absorption device and the first heat exchanger of the first solution compound from a fourth solution compound. The fourth solution link is at the end where the

Solution stream exits again from the fourth solution compound, with the first

Solution connection connected after the first heat exchanger or the absorption device. The fourth solution compound has a fifth heat exchanger. The fifth heat exchanger is connected to the second heat exchanger in such a way that the heat exchange medium cooled in the second heat exchanger flows into the fifth

Heat exchanger is performed. As a result, the maximum amount of thermal energy can be obtained from the heat exchange medium, usually steam, and so the entire

Energy requirements are in turn reduced.

In another embodiment of the invention, the fourth solution compound is am

End, where the solution stream exits again from the fourth solution connection, with the

Evaporation device connected. In this way, as in the case of the heated solution stream of the first solution compound, expansion can take place here and the gas phase can be separated from the liquid phase.

7 BE2021/6008

In another embodiment of the invention, the carbon dioxide outlet is connected to a first carbon dioxide compressor. The first carbon dioxide compressor is connected to a first carbon dioxide heat exchanger in order to cool down the carbon dioxide heated by the compression again. This is common, since both for dumping and for further processing of carbon dioxide, for example to form methanol, the

Carbon dioxide is required at a higher pressure. Usually there are one

A number of carbon dioxide compressors and carbon dioxide heat exchangers are cascaded in series in order to compress the carbon dioxide in stages and cool it again and again in between. Between the

A fifth solution connection branches off from the absorption device and the first heat exchanger of the first solution connection. The fifth solution connection is at the end where the solution stream exits the fifth solution connection again, with the first

Solution connection connected after the first heat exchanger or the absorption device. The fifth solution compound includes the first carbon dioxide heat exchanger. This allows the thermal energy generated by compressing the

Carbon dioxide generated is used for the process. Is a plural on

Carbon dioxide heat exchangers present, these are preferably parallel in the fifth

Integrated solution connection.

In another embodiment of the invention, the fifth solution compound is am

End, where the solution stream exits again from the fifth solution connection, with the

Evaporation device connected. In this way, as in the case of the heated solution stream of the first solution compound, expansion can take place here and the gas phase can be separated from the liquid phase.

In another embodiment of the invention, the pressure of the solvent is in the second

Heat exchanger is 0.2 bar to 5 bar higher than the pressure in the

Desorption device at the absorption solvent outlet. In the second heat exchanger, a higher initial temperature can thus be achieved because of the increased

Pressure, the temperature can be increased up to the boiling point at the appropriate pressure. This in turn means that the solvent on

Absorption solvent outlet has a higher temperature and thus enters the first heat exchanger at a higher temperature. As a result, this can either be made more compact or a higher starting temperature for the

8 BE2021/6008 laden solution stream can be achieved from the first heat exchanger. The latter in turn leads to more efficient expulsion of the carbon dioxide from the solution.

Here, the pressure of the solvent in the second heat exchanger is dependent on the equipment. To the

There are two exemplary and preferred ways to set the pressure in a targeted manner using equipment

embodiments. In a first exemplary and preferred embodiment of the

Invention, the pressure of the solvent in the second heat exchanger is characterized by 0.2 bar to 5 bar higher than the pressure in the desorption device at the absorption solvent outlet that the second heat exchanger by at least 1 m below the

Absorption solvent outlet is arranged, whereby the pressure in the second

Heat exchanger is generated by the hydrostatic pressure of the liquid column of the solvent. In a second exemplary and preferred embodiment of the

Invention, the pressure of the solvent in the second heat exchanger is thereby 0.2 bar to 5 bar higher than the pressure in the desorption device at the absorption solvent outlet that a first pump for generating the corresponding overpressure is arranged in front of the second heat exchanger.

In a further embodiment of the invention between the second

Heat exchanger and the desorption device, arranged a pressure loss device, such as a control valve, a pinhole or a constriction. With the pressure loss device, the desired overpressure is achieved in the second

Heat exchanger gas / steam set or maintained. In this way, if necessary, evaporation can already be prevented in the second heat exchanger.

The first solution inlet is preferably arranged in the middle region of the desorption device.

The carbon dioxide separation device according to the invention is explained in more detail below with reference to exemplary embodiments illustrated in the drawings.

1 first exemplary embodiment

2 second exemplary embodiment

3 third exemplary embodiment

9 BE2021/6008

In Fig. 1 is a first exemplary embodiment of an inventive

Carbon dioxide separation device 10 shown. The carbon dioxide

Separation device 10 is used, for example, for separating the carbon dioxide from an exhaust gas flow, which enters the gas inlet 21 and is greatly depleted in carbon dioxide and exits at the gas outlet 22 . In the absorption device 20, this gas flow is brought into contact with a solvent, usually an amine solution, in countercurrent, so that the carbon dioxide dissolves. This solution takes effect on

Solution outlet 24 from the absorption device and is through a second

Pump 46 is pumped through the first solution junction 40. The first solution connection 40 has a first heat exchanger 41 by the solution flow through the

Solvent flow of the absorption solvent compound 50 is heated. The first

Heat exchanger 41 downstream is an evaporation device 42 in which the

Solution can partially pass into the gas phase. The liquid phase of

Solution stream is further promoted through the first solution connection 40, for example by means of a third pump 47 through the first solution inlet 31 into the desorption device 30. The resulting gas in the evaporation device 42 is through the

Vapor outlet 43 into the gas solution connection 44 and through this via the

Steam inlet 35 into the desorption device 30 out. The steam inlet 35 is preferably located at the lower end, the bottom, of the desorption device 30.

In the desorption device 30 the carbon dioxide is thermally removed from the solution and discharged via the carbon dioxide outlet 34 . This carbon dioxide stream can then be fed, for example, either to a further reaction or to landfill. The solvent freed from carbon dioxide collects at the bottom of the

Desorption device 30 and is through the absorption solvent outlet 32 of

Absorption solvent compound 50 supplied. The solvent flow is here in the first

Heat exchanger 41 from its thermal energy to the solution stream. For example, by means of a fourth pump, the solvent stream reaches the absorption device via a third heat exchanger 55 through the absorption solvent inlet 23 .

From the solvent flow in the absorption solvent connection 50, a partial flow branches off at the branch 51, which flows through the warm solvent connection 52 via the second

Heat exchanger 53 is conveyed back into the desorption device 30 in particular in vapor form or as a vapor/liquid mixture through the warm solvent inlet 33 . Over

10 BE2021/6008 the second heat exchanger 53, the energy required for expelling the

Carbon dioxide from the solution fed to the system.

A third solution connection 60 , which has a fourth heat exchanger 61 , also branches off from the first solution connection 40 . The third solution connection 60 opens at the end into the evaporation device 42. The energy, which in the fourth

Heat exchanger 61 is transferred to the solution stream comes from the dated

Carbon dioxide to be cleaned gas stream. To this guest stream then in the

To transfer absorption device 20 are the fourth heat exchanger 61 and the

Gas inlet 21 of the absorption device 20 connected via the gas connection 25. The

Gas connection 25 also has a raw gas cleaning 26, in which SOx is removed and also brings the gas flow to the right temperature for the absorption of the

carbon dioxide in the absorption device 20.

Fig. 2 shows a second exemplary embodiment, which differs from the first exemplary embodiment in that an additional fourth

Solution connection 62 is present, which leads a partial flow of the solution flow in via the fifth heat exchanger 63 into the evaporation device 42 . The energy to

Warming of the solution stream in the fifth heat exchanger 63 comes from the heat exchange medium that has already cooled in the second heat exchanger 53

Residual heat is thus used efficiently.

A third exemplary embodiment is shown in FIG. In addition to the second exemplary embodiment, FIG

Carbon dioxide heat exchanger 37 on. To the generated by the compression and in the

To use carbon dioxide heat exchanger 37 emitted heat, the carbon dioxide

Separation device 10 on a fifth solution compound 64, which one

Partial stream of the solution stream through the carbon dioxide heat exchanger 37 in the

Evaporation device 42 leads.

Numeral 10 carbon dioxide separation device 20 absorption device

11 BE2021/6008 21 gas inlet 22 gas outlet 23 absorption solvent inlet 24 solution outlet 25 gas connection 26 raw gas cleaning 30 desorption device 31 first solution inlet 32 absorption solvent outlet 33 warm solvent inlet 34 carbon dioxide outlet 35 steam inlet 36 carbon dioxide compressor 37 carbon dioxide heat exchanger 40 first solution connection 41 first heat exchanger 42 evaporation device 43 vapor outlet 44 gas solution connection 45 second solution connection 46 second pump 47 third pump 50 absorption solvent connection 51 branch 52 warm solvent connection 53 second heat exchanger 54 first pump 55 third heat exchanger 60 third solution connection 61 fourth heat exchanger 62 fourth solution connection 63 fifth heat exchanger 64 fifth solution connection

Claims (13)

12 BE2021/6008 patent claims 1. Carbon dioxide separation device (10), wherein the carbon dioxide separation device (10) has an absorption device (20) and a desorption device (30), the absorption device (20) having a gas inlet (21) for the gas to be cleaned and a gas outlet ( 22) for the cleaned gas, wherein the absorption device (20) has an absorption solvent inlet (23) and a solution outlet (24), wherein the desorption device (30) has at least a first solution inlet (31), an absorption solvent outlet (32), a warm solvent inlet ( 33) and a carbon dioxide outlet (34), the solution outlet (24) being connected to the first solution inlet (31) via a first solution connection (40), the first solution connection (40) having a first heat exchanger (41), the The absorption solvent outlet (32) is connected to the absorption solvent inlet (23) via an absorption solvent connection (50), the absorption solvent connection (50) having the first heat exchanger (41) so that the heat of the solvent stream is transferred to the solution stream, the absorption solvent connection (50) has a branch (51) to a warm solvent connection (52), the warm solvent connection (52) being connected to the warm solvent inlet (33), the warm solvent connection having a second heat exchanger (53), characterized in that between the absorption device (20) and a third solution connection (60) branches off the first heat exchanger (41) from the first solution connection (40), the third solution connection (60) being connected at the end to the first solution connection (40) downstream of the first heat exchanger (41) or the absorption device (20) is connected, the third solution connection (60) having a fourth heat exchanger (61), the fourth heat exchanger (61) and the gas inlet (21) being connected via a gas connection (25), so that the gas to be cleaned flows through the fourth heat exchanger ( 61) before the gas to be cleaned is fed into the absorption device (10). 2. carbon dioxide separation device (10) according to claim 1, characterized in that the first solution compound (40) fluidically 13 BE2021/6008 has an evaporation device (42) downstream of the first heat exchanger (41), the liquid phase of the solution stream being separated from the gaseous phase of the solution stream in the evaporation device (42), the liquid phase being separated by the first solution connection (40) into the desorption device (30), the desorption device (30) having a steam inlet (35), the evaporation device (42) having a steam outlet (43), the steam outlet (43) and the steam inlet (35) for transferring the gaseous phase are connected to a gas solution compound (44). 3. Carbon dioxide separation device (10) according to claim 2, characterized in that the third solution connection (60) is connected at the end to the evaporation device (42). 4. carbon dioxide separation device (10) according to any one of the preceding claims, characterized in that the gas connection (25) has a raw gas cleaning (26). 5. Carbon dioxide separation device (10) according to claim 4, characterized in that the raw gas cleaning (25) is designed to remove sulfur oxides. 6. Carbon dioxide separation device (10) according to one of the preceding claims, characterized in that between the absorption device (20) and the first heat exchanger (41) a second solution connection (45) branches off from the first solution connection (40), the second solution connection (45) leads directly into the head of the desorption device (30). 7. Carbon dioxide separation device (10) according to one of the preceding claims, characterized in that between the absorption device (20) and the first heat exchanger (41) a fourth solution connection (62) branches off from the first solution connection (40), the fourth solution connection (62) at the end with the first solution connection (40) after the first heat exchanger (41) or the absorption device (20) 14 BE2021/6008, the fourth solution connection (62) having a fifth heat exchanger, the fifth heat exchanger (63) being connected to the second heat exchanger (53) in such a way that the heat exchange medium cooled in the second heat exchanger (53) flows into the fifth Heat exchanger (63) is performed. 8. Carbon dioxide separation device (10) according to claim 7 when appendant to claim 2, characterized in that the fourth solution connection (62) is connected at the end to the evaporation device (42). 9. Carbon dioxide separation device (10) according to any one of the preceding claims, characterized in that the carbon dioxide outlet (34) is connected to a first carbon dioxide compressor (36), the first carbon dioxide compressor (36) being connected to a first carbon dioxide heat exchanger (37), A fifth solution connection (65) branches off from the first solution connection (40) between the absorption device (20) and the first heat exchanger (41), the fifth solution connection (65) at the end having the first solution connection (40) behind the first heat exchanger (41 ) or the absorption device (20) is connected, wherein the fifth solution connection (65) comprises the first carbon dioxide heat exchanger (37). 10. Carbon dioxide separation device (10) according to claim 9 when appendant to claim 2, characterized in that the fifth solution connection (65) is connected at the end to the evaporation device (42). 11. Carbon dioxide separation device (10) according to any one of the preceding claims, characterized in that the pressure of the solvent in the second heat exchanger (53) is 0.2 bar to 5 bar higher than the pressure in the desorption device (30) at the absorption solvent outlet ( 32). 12. Carbon dioxide separation device (10) according to claim 11, characterized in that the pressure of the solvent in the second heat exchanger (53) is thereby 0.2 bar to 5 bar higher than the pressure in the desorption device (30) at the absorption solvent outlet (32 ) that the second heat exchanger (53) to 15 BE2021/6008 is placed at least 1 m below the absorption solvent outlet (32) so that the pressure is generated by the hydrostatic pressure of the solvent. 13. Carbon dioxide separation device (10) according to claim 11, characterized in that the pressure of the solvent in the second heat exchanger (53) is thereby 0.2 bar to 5 bar higher than the pressure in the desorption device (30) at the absorption solvent outlet (32 ) That before the second heat exchanger (53) a first pump (54) is arranged for generating the overpressure.