CN116510467A - Carbon trapping system - Google Patents

Abstract

This application provides a carbon capture system, drying tower, main heat exchanger, spray tower equipment and carbon capture liquid supply equipment; the flue gas dehydrated through the drying tower enters the main heat exchanger, and the main heat exchanger The flue gas after the precooling treatment enters the spray tower equipment, and the carbon capture liquid input into the spray tower equipment by the carbon capture liquid supply equipment in the spray tower equipment cools down, and the carbon dioxide in the flue gas Cool down to the desublimation temperature of carbon dioxide to obtain dry ice, liquefy the dry ice to obtain liquid carbon dioxide, and obtain high-concentration liquid carbon dioxide after the liquid carbon dioxide passes through the main heat exchanger. Through the carbon capture system provided in the embodiment of the present application, the evaporation of the carbon capture liquid by the flue gas can be reduced.

Description

A carbon capture system

technical field

This application relates to the technical field of carbon capture, in particular, to a carbon capture system.

Background technique

At present, the desublimation method in the low-temperature carbon capture method has attracted more and more attention. The desublimation method refers to the use of the flue gas discharged from the power plant to be input into the low-temperature (temperature below 195k (-78.15°C)) carbon capture equipment, and the carbon capture liquid in the box-type low-temperature carbon capture equipment is used to cool the flue gas. However, if the temperature of the flue gas is high, it will cause the carbon capture liquid to desublimate the carbon dioxide in the flue gas. The collection liquid evaporates, which will reduce the carbon capture liquid's capture efficiency of carbon dioxide in the flue gas.

Contents of the invention

In order to solve the above problems, the purpose of the embodiments of the present application is to provide a carbon capture system.

In the first aspect, the embodiment of the present application provides a carbon capture system, including: a drying tower, a main heat exchanger, a spray tower device and a carbon capture liquid supply device;

The drying tower, the main heat exchanger, the spray tower equipment and the carbon capture liquid supply equipment are sequentially connected;

The flue gas dehydrated by the drying tower enters the main heat exchanger, and the main heat exchanger performs pre-cooling treatment on the flue gas, and the pre-cooled flue gas enters the spray tower equipment, where In the spray tower equipment, the carbon capture liquid input into the spray tower equipment by the carbon capture liquid supply equipment is cooled, and the carbon dioxide in the flue gas is cooled to the desublimation temperature of carbon dioxide to obtain dry ice. The dry ice is liquefied to obtain liquid carbon dioxide, and the liquid carbon dioxide passes through the main heat exchanger to obtain high-concentration liquid carbon dioxide.

In the scheme provided by the first aspect of the embodiment of the present application, the main heat exchanger installed in the carbon capture system is used to pre-cool the flue gas dehydrated by the drying tower, which is different from the use of carbon capture liquid in the related technology to cool the high-temperature flue gas. Compared with the method of desublimation that will cause a large amount of carbon capture liquid to evaporate, the main heat exchanger is used to pre-cool the flue gas before the flue gas enters the spray tower equipment to reduce the amount of flue gas entering the spray tower equipment. temperature, so that the temperature of the flue gas entering the spray tower equipment is reduced, and the flue gas with reduced temperature is cooled to the desublimation temperature of carbon dioxide by the carbon capture liquid, due to the temperature difference between the flue gas with reduced temperature and the carbon capture liquid reduce the evaporation of the carbon capture liquid by the flue gas; moreover, use the spray tower equipment to collect the dry ice after the carbon dioxide in the flue gas is sublimated, and avoid using the box-type low-temperature carbon capture equipment to collect the dry ice as much as possible. During the capture process, dry ice condenses on the inner wall of the box-type low-temperature carbon capture equipment, resulting in difficulties in dry ice collection, corrosion of equipment, and poor thermal conductivity.

In order to make the above-mentioned purpose, features and advantages of the present application more comprehensible, preferred embodiments will be described in detail below together with the accompanying drawings.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present application. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 shows a schematic structural diagram of a carbon capture system provided in Example 1 of the present application.

Detailed ways

In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " Orientation or position indicated by "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. The relationship is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, therefore It should not be construed as a limitation of the application.

In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, a feature defined as "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present application, "plurality" means two or more, unless otherwise specifically defined.

In this application, terms such as "installation", "connection", "connection" and "fixation" should be interpreted in a broad sense, for example, it can be a fixed connection or a detachable connection, unless otherwise clearly specified and limited. , or integrally connected; it may be mechanically connected or electrically connected; it may be directly connected or indirectly connected through an intermediary, and it may be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in this application according to specific situations.

Carbon dioxide capture is the research focus of carbon emission reduction technology. Improving capture efficiency and reducing equipment energy consumption are related to the prospect of industrial application and the achievement of the national double carbon target. As a large carbon emission country and a large coal country, my country's carbon emissions mainly come from coal-fired power generation in thermal power plants, and its carbon emissions are characterized by large emissions, concentrated emissions, and low carbon dioxide concentrations. There are three main types of carbon capture technologies, including: pre-combustion capture technology, oxyfuel combustion capture technology, and post-combustion capture technology. Among them, post-combustion capture has better adaptability and does not need to modify the existing power plant system, so it is more suitable for my country's national conditions. Post-combustion capture technology can be subdivided into: absorption method, adsorption method, membrane separation method, biological microalgae treatment method and low temperature method, etc.

In recent years, the desublimation method in the cryogenic method has attracted more and more attention. The desublimation method refers to inputting the flue gas discharged from the power plant into a low-temperature (temperature lower than 195k (-78.15°C)) carbon capture equipment, and using the carbon capture liquid in the box-type low-temperature carbon capture equipment to reduce the concentration of the flue gas. Carbon dioxide is sublimated to obtain solid dry ice of carbon dioxide, and then the desublimated dry ice is collected and recovered. This method has the characteristics of high capture rate, high concentration of captured carbon dioxide, and no secondary pollutants, which is green and environmentally friendly. However, if the temperature of the flue gas is high, the carbon capture liquid will evaporate during the process of desublimation of the carbon dioxide in the flue gas by the carbon capture liquid, which will reduce the capture efficiency of the carbon capture liquid for carbon dioxide in the flue gas .

Based on this, the following embodiments of this application propose a carbon capture system, using the main heat exchanger installed in the carbon capture system to pre-cool the flue gas dehydrated by the drying tower to reduce the amount of flue gas entering the spray tower equipment. temperature, so that the temperature of the flue gas entering the spray tower equipment is reduced, and the flue gas with reduced temperature is cooled to the desublimation temperature of carbon dioxide by the carbon capture liquid, due to the temperature difference between the flue gas with reduced temperature and the carbon capture liquid The reduction can reduce the evaporation of the carbon capture liquid from the flue gas, thereby improving the capture efficiency of the carbon dioxide in the flue gas by the carbon capture liquid; moreover, the dry ice after the desublimation of carbon dioxide in the flue gas is treated by using the spray tower equipment. Collection, try to avoid the defects of dry ice collection difficulty, corrosion equipment and poor thermal conductivity caused by dry ice condensation on the inner wall surface of the box-type low-temperature carbon capture equipment during the dry ice capture process using box-type low-temperature carbon capture equipment.

In order to make the above purpose, features and advantages of the present application more obvious and understandable, the present application will be further described in detail below in conjunction with the accompanying drawings and embodiments.

Example

Referring to the schematic structural diagram of the carbon capture system shown in FIG. 1 , this embodiment proposes a carbon capture system, including: a drying tower 1 , a main heat exchanger 2 , a spray tower device and a carbon capture liquid supply device.

The drying tower 1, the main heat exchanger 2, the spray tower equipment and the carbon capture liquid supply equipment are connected in sequence.

The flue gas dehydrated by the drying tower 1 enters the main heat exchanger 2, and the main heat exchanger 2 pre-cools the flue gas, and the pre-cooled flue gas enters the spray tower equipment , in the spray tower equipment, the carbon capture liquid input into the spray tower equipment by the carbon capture liquid supply equipment is cooled, and the carbon dioxide in the flue gas is cooled to the desublimation temperature of carbon dioxide to obtain Dry ice, the dry ice is liquefied to obtain liquid carbon dioxide, and the liquid carbon dioxide passes through the main heat exchanger 2 to obtain high-concentration liquid carbon dioxide.

In one embodiment, the high concentration of liquid carbon dioxide may refer to the low concentration of liquid carbon dioxide greater than or equal to 80%.

Among them, the drying tower 1 is used to dehydrate and dry the flue gas that has undergone dust removal, desulfurization and denitrification, so as to prevent ice blockage in the pipeline.

The main heat exchanger 2 is used to pre-cool the dried flue gas, reduce the temperature of the flue gas to reduce the evaporation of the carbon capture liquid in the next step, and recover the cooling capacity of the flue gas and liquid carbon dioxide after carbon removal.

In order to better desublimate the carbon dioxide in the flue gas, the carbon capture liquid may be, but not limited to: isopentane liquid or isopentane-n-pentane mixed liquid. Preferably, if a carbon capture liquid with a lower temperature and a higher carbon capture rate is desired, more isopentane liquid components are added to the carbon capture liquid.

Exemplarily, when the carbon capture liquid adopts low-temperature isopentane liquid, the temperature of the low-temperature isopentane liquid may be, but not limited to: the temperature of the low-temperature isopentane liquid with 80% carbon capture rate is 168.15K (-105°C ), the temperature of the low-temperature isopentane liquid with 90% carbon capture rate is 153.15K (-120°C), and the temperature of the low-temperature isopentane liquid with 99% carbon capture rate is 138.15K (-135°C).

In order to further improve the capture efficiency of carbon dioxide in the flue gas, in the carbon capture system proposed in this embodiment, the spray tower equipment includes: a first spray tower 3 and a second spray tower 4; correspondingly, The carbon capture liquid includes: the first liquid capture medium input into the first spray tower 3 and the second liquid capture medium input into the second spray tower 4; the dry ice comprises: the first spray tower 3 the first part of dry ice obtained and the second part of dry ice obtained in the second spray tower 4.

From the above description, it can be known that the first liquid trapping medium and the second liquid trapping medium can respectively adopt but not limited to: isopentane liquid or isopentane-n-pentane mixed liquid.

Optionally, the first spray tower 3 and the second spray tower 4 can be separately used as low-temperature spray towers.

In one embodiment, the first spray tower 3 and the second spray tower 4 are respectively provided with a solid-liquid collection tank, a lower air inlet, an upper carbon capture liquid inlet, a nozzle, and a top gas outlet; The liquid collection tank is arranged on the bottom of the first spray tower 3 and the second spray tower 4 respectively, and the lower air inlet can be arranged on the bottom of the first spray tower 3 and the second spray tower 4 respectively and the lower air inlet The air intake method is from bottom to top. The upper carbon capture liquid inlet can be respectively set on the upper part of the first spray tower 3 and the second spray tower 4. The upper carbon capture liquid inlet is connected to the nozzle through a hose, and the top outlet The gas ports are arranged on the tops of the first spray tower 3 and the second spray tower 4 respectively.

The top air outlet of the first spray tower 3 is connected to the lower air inlet of the second spray tower 4 ; the top air outlet of the second spray tower 4 is connected to the main heat exchanger 2 .

The first spray tower 3 is connected with the main heat exchanger 2 and the second spray tower 4 respectively, and the first spray tower 3 and the second spray tower 4 are respectively connected with the carbon Capture liquid supply equipment connection.

Among them, the first spray tower 3 is used to lower the temperature of the carbon dioxide gas in the flue gas to below the desublimation point by spraying the first liquid trapping medium with the first temperature under atmospheric pressure, and remove most of the flue gas The carbon dioxide is separated in the form of dry ice, and the first part of dry ice is obtained and collected.

The second spray tower 4 is used to lower the temperature of the carbon dioxide gas in the flue gas to below the desublimation point by spraying the second liquid trapping medium with the second temperature under atmospheric pressure. The first liquid capture medium sprayed by the shower tower 3 has a lower temperature and the second liquid capture medium desublimes the carbon dioxide in the cold flue gas, and the remaining carbon dioxide in the cold flue gas after the carbon capture in the first spray tower 3 The carbon dioxide is subjected to secondary desublimation, and the second part of dry ice obtained after secondary desublimation is collected.

The pre-cooled flue gas enters the first spray tower 3, and is input into the first spray tower 3 by the carbon capture liquid supply equipment in the first spray tower 3, The temperature of the first liquid capture medium with the first temperature is lowered, the carbon dioxide in the flue gas is cooled to the desublimation temperature of carbon dioxide, and the first part of dry ice and cold flue gas are obtained, and the first part of dry ice is liquefied to obtain the The first part of the liquid carbon dioxide of the dry ice, the liquid carbon dioxide of the first part of the dry ice passes through the main heat exchanger to obtain high-concentration liquid carbon dioxide, and the cold flue gas is input into the second spray tower.

The first liquid capture medium input to the first spray tower 3 by the carbon capture liquid supply equipment is sprayed onto the flue gas by the nozzles in the first spray tower 3 to cool down the flue gas. The cold flue gas is obtained after the flue gas is cooled by the first liquid trapping medium with the first temperature in the first spray tower 3 . The temperature of the cold flue gas is lower than that of the flue gas after the pre-cooling operation.

Specifically, the pre-cooled flue gas enters the first spray tower 3 from the lower air inlet of the first spray tower 3, and is captured by the carbon in the first spray tower 3 The liquid supply equipment is input into the first spray tower, and the first liquid trapping medium with the first temperature is sprayed and cooled to obtain the first part of dry ice and cold flue gas; wherein, the first liquid trapping medium is It enters into the first spray tower through the upper carbon capture liquid inlet arranged on the upper part of the first spray tower 3 .

In order to better collect the dry ice, solid-liquid collection tanks (not shown in the figure) are respectively provided at the bottoms of the first spray tower 3 and the second spray tower 4 . In the first spray tower 3, the first part of dry ice and part of the first liquid trapping medium will fall into the bottom solid-liquid collection tank, and flow out of the first spray tower 3 from the bottom of the solid-liquid collection tank, and out of the first After the first part of the dry ice in the spray tower 3 is liquefied, the liquid carbon dioxide of the first part of the dry ice is obtained.

The cold flue gas output from the first spray tower 3 enters the second spray tower 4, and is input into the second spray tower 4 by the carbon capture liquid supply equipment in the second spray tower The temperature of the second liquid trapping medium with the second temperature is lowered, the carbon dioxide in the cold flue gas is lowered to the desublimation temperature of carbon dioxide, and the second part of dry ice is obtained. After the second part of dry ice is liquefied, the obtained The second part of the liquid carbon dioxide of the dry ice, the liquid carbon dioxide of the second part of the dry ice passes through the main heat exchanger 2 to obtain a high concentration of liquid carbon dioxide; wherein, the first temperature is higher than the second temperature.

In one embodiment, the first temperature is higher than the second temperature, but both are lower than the desublimation temperature of carbon dioxide. Specifically, the cold flue gas is output from the top gas outlet provided at the top of the first spray tower 3, and enters the second spray tower 4 from the lower air inlet of the second spray tower 4, where the second In the spray tower 4, the second liquid trap medium with a second temperature, which is input into the second spray tower 4 by the carbon trap liquid supply equipment, is cooled to obtain the second part of dry ice; wherein, The second liquid trapping medium enters the second spray tower 4 through the upper carbon trap liquid inlet arranged on the upper part of the second spray tower 4 .

In the second spray tower 4, the second part of the dry ice and part of the second liquid trapping medium will fall into the solid-liquid collection tank arranged in the second spray tower 4, and flow out of the first solid-liquid collection tank from the bottom of the solid-liquid collection tank. The second spray tower 4, after the second part of dry ice flowing out of the second spray tower 4 is liquefied, the liquid carbon dioxide of the second part of dry ice is obtained.

For example, if the first liquid capture medium with the first temperature uses low-temperature isopentane liquid with a temperature of 168.15K (-105°C) and a carbon capture rate of 80%, then the second capture medium with the second temperature The liquid capture medium can use low-temperature isopentane liquid with a temperature of 153.15K (-120°C) and a carbon capture rate of 90%, or a low-temperature isopentane liquid with a temperature of 138.15K (-135°C) and a carbon capture rate of 99%. alkane liquid.

If the first liquid capture medium with the first temperature uses a low-temperature isopentane liquid with a temperature of 153.15K (-120°C) and a 90% carbon capture rate, then the second liquid capture medium with the second temperature A low temperature isopentane liquid with a temperature of 138.15K (-135°C) and a carbon capture rate of 99% can be used.

Moreover, there is not much carbon dioxide gas in the cold flue gas sent to the second spray tower in the flue gas and the temperature is relatively low, so the droplet mass of the second liquid trapping medium sprayed by the second spray tower is also smaller than that of the second spray tower. The droplet mass of the first liquid trapping medium sprayed by a spray tower.

In one embodiment, the droplet mass can be adjusted according to the intake air volume, but the general principle is that the first liquid trapping medium sprayed by the first spray tower 3 is higher than the second trap medium sprayed by the second spray tower 4 . The liquid trapping medium has many droplets but the temperature of the first liquid trapping medium is higher than that of the second liquid trapping medium.

Optionally, the droplet diameters of the first liquid trapping medium and the second liquid trapping medium are less than or equal to 2 mm.

As can be seen from the above description, the first spray tower 3 has a larger volume than the second spray tower 4, and the first liquid trapping medium in the first spray tower 3 is larger than that in the second spray tower 4. The temperature of the second liquid trapping medium is higher. Then, the first spray tower 3 and the second spray tower 4 are used in series, the first spray tower 3 is used to remove most of the carbon dioxide in the flue gas, and the rest enters the second spray tower 4 to use a lower The temperature of the carbon capture liquid for carbon capture. For example, the first spray tower 3 can desublimate 80% of the carbon dioxide in the flue gas, and the second spray tower 4 can desublimate 90% of the carbon dioxide in the cold flue gas. Of course, the carbon capture ratio of the first spray tower 3 and the second spray tower 4 can also be freely adjusted according to actual needs, and it is also possible to completely use the first spray tower 3 for carbon capture. Then, the main purpose of using the first spray tower 3 and the second spray tower 4 in series for carbon capture of carbon dioxide is to make the carbon capture capacity of the carbon capture system more adjustable and to further save energy consumption.

By setting the first spray tower 3 and the second spray tower 4 in a stepwise manner, the carbon capture rate of the carbon capture system can reach 99%, which has the characteristics of higher carbon capture rate and energy saving.

In order to discharge the flue gas after the carbon capture operation obtained after the treatment of the first spray tower 3 and the second spray tower 4, the carbon capture system proposed in this embodiment also includes: 2 connected chimneys; the second spray tower 4 can also obtain the flue gas after the carbon capture operation while obtaining the second part of dry ice, and the flue gas after the carbon capture operation is captured by the first After the secondary spray tower 4 is discharged, it is discharged from the chimney after the heat exchange operation of the main heat exchanger 2 . Wherein, the flue gas after the carbon capture operation is discharged from the top gas outlet provided on the top of the second spray tower 4 .

The main heat exchanger 2 performs a heat exchange operation on the flue gas after the carbon capture operation (that is, the flue gas discharged from the top gas outlet provided at the top of the second spray tower 4), and the flue gas after the carbon capture operation The cold energy carried by the flue gas is recovered, and the recovered cold energy is used to pre-cool the flue gas dehydrated by the drying tower. Therefore, the cold energy carried by the flue gas after the carbon capture operation can be recycled, and the carbon dioxide capture efficiency can be improved as much as possible while the consumption of carbon capture liquid is not increased as much as possible, which has the advantages of green environmental protection and energy saving.

In order to be able to input the first liquid capture medium with the first temperature to the first spray tower 3, and to input the second liquid capture medium with the second temperature to the second spray tower 4, specifically, in this embodiment In the proposed carbon capture system, the carbon capture liquid supply equipment includes: a first refrigeration heat exchanger 8 and a second refrigeration heat exchanger 13; the first refrigeration heat exchanger 8 and the first refrigeration heat exchanger The spray tower 3 is connected; the second refrigeration heat exchanger 13 is connected with the second spray tower 4 .

The first refrigeration heat exchanger 8 can input the first liquid capture medium with the first temperature to the first spray tower 3 . The second refrigeration heat exchanger 13 can input the second liquid capture medium with the second temperature to the second spray tower 4 .

In order to supplement the second liquid capture medium in the second refrigeration heat exchanger 13 , the second refrigeration heat exchanger 13 is provided with a carbon capture liquid replenishment inlet. By providing a carbon capture liquid replenishment inlet on the second refrigeration heat exchanger 13, the carbon capture liquid taken away by the flue gas or evaporated can be supplemented to ensure the carbon capture efficiency of the carbon capture system.

In order to liquefy the dry ice flowing out of the first spray tower 3 and the second spray tower 4, it is necessary to liquefy the mixture of the first part of the dry ice flowing out of the first spray tower 3 and part of the first liquid trapping medium and the mixture of the second spray tower 4. The mixture of the second part of dry ice and part of the second liquid trapping medium in the shower tower 4 is subjected to solid-liquid separation respectively, that is, it is necessary to perform solid-liquid separation on the dry ice and the carbon trapping liquid flowing out of the shower tower equipment. In order to separate the dry ice and the carbon capture liquid flowing out of the spray tower equipment into solid and liquid, the carbon capture system proposed in this embodiment further includes: a circulation pump 5 , a solid-liquid separator 6 and a melting pump 7 .

The circulation pump 5 is connected with the first spray tower 3, the second spray tower 4 and the solid-liquid separator 6 respectively; the solid-liquid separator 6 is also connected with the first refrigeration heat exchanger 8 is connected to the melting pump 7; the melting pump 7 is also connected to the main heat exchanger 2.

The circulation pump 5 is used to transport the dry ice and part of the carbon capture liquid mixture flowing out of the spray tower equipment to the solid-liquid separator 6 .

The solid-liquid separator 6 is used to separate the dry ice from the carbon capture liquid by rolling.

The melting pump 7 is used to liquefy the dry ice into liquid carbon dioxide, and send the liquid carbon dioxide to the main heat exchanger 2 for cooling recovery.

The mixture of the dry ice and the carbon capture liquid flows out from the bottom of the first spray tower and the bottom of the second spray tower respectively, and enters the solid-liquid separator 6 after passing through the circulating pump 5 for solid-liquid separation. The dry ice and the carbon capture liquid are separated from the mixture of the dry ice and the carbon capture liquid.

Optionally, the solid-liquid separator 6 separates the dry ice and the carbon-capturing liquid from the mixture of the dry ice and the carbon-capturing liquid by rolling.

The separated dry ice is delivered to the melting pump 7, and after being heated and liquefied by the melting pump 7, the liquid carbon dioxide is obtained, and the liquid carbon dioxide enters the main heat exchanger 2 and passes through the main heat exchange After the cooling capacity of device 2 is recovered, high-concentration liquid carbon dioxide is obtained. Therefore, the cold energy carried by the liquid carbon dioxide to be stored can be recycled, and the cold energy in the liquid carbon dioxide can be recycled while the carbon dioxide is captured, and the recovered cold energy can be used to pre-cool the flue gas, which has the advantages of The advantages of green environmental protection and energy saving.

The separated carbon capture liquid is input into the first refrigeration heat exchanger, and after being cooled to a first temperature by the first refrigeration heat exchanger, the carbon capture liquid is transported to the The flue gas in the first spray tower is desublimated in the first spray tower. By inputting the separated carbon capture liquid into the first refrigeration heat exchanger, the part of the carbon capture liquid flowing out of the spray tower equipment is recycled to reduce the carbon capture liquid as much as possible. Replenishment, reduce the use cost of carbon capture system.

When the liquid carbon dioxide passes through the main heat exchanger, the main heat exchanger performs heat exchange operation on the passing liquid carbon dioxide, and recovers the cold energy carried in the liquid carbon dioxide through the heat exchange operation, and the recovered cold energy is used for the drying tower The dehydrated flue gas is pre-cooled. Therefore, the cold energy carried by the liquid carbon dioxide to be stored can be recycled, and the cold energy in the liquid carbon dioxide can be recycled while the carbon dioxide is captured, and the recovered cold energy can be used to pre-cool the flue gas, which has the advantages of The advantages of green environmental protection and energy saving.

In order to cool down and recycle part of the carbon capture liquid flowing out of the spray tower equipment, the carbon capture system proposed in this embodiment also includes: a first compressor 9, a second compressor 11, and a first throttle valve 10 and the second throttle valve 12; the first compressor 9 and the first throttle valve 10 are connected to each other, and are respectively connected to the first refrigeration heat exchanger 8; the second compressor 11 and The second throttle valves 12 are connected to each other and connected to the second refrigeration heat exchangers 13 respectively.

Specifically, the first refrigeration heat exchanger 8 and the second refrigeration heat exchanger 13 are respectively provided with: a refrigerant outlet and a refrigerant inlet; wherein, the refrigerant outlet of the first refrigeration heat exchanger 8 passes through the first throttling valve 10 is connected to one side of the first compressor 9, and the other side of the first compressor is connected to the refrigerant inlet of the first refrigeration heat exchanger. The refrigerant outlet of the second refrigeration heat exchanger 13 is connected to one side of the second compressor 12 through the second throttle valve 12, and the other side of the second compressor 12 is connected to the refrigerant of the second refrigeration heat exchanger 13 Entrance.

By arranging the first compressor 9 and the first throttling valve 10 connected with the first refrigeration heat exchanger 8, the refrigerant output from the first compressor 9 is used to lower the temperature of part of the carbon capture liquid flowing out from the spray tower equipment to The first temperature achieves the purpose of recycling part of the carbon capture liquid flowing out of the spray tower equipment.

The second refrigeration heat exchanger 13, the second compressor 12 and the second throttle valve 11 cool down the temperature of the isopentane liquid by exchanging heat with the refrigerant, and supplement the isopentane liquid from the outside. The temperature of the second liquid capture medium sprayed by the second spray tower is lower than that of the first liquid capture medium sprayed by the first spray tower, and considering the storage or use of several carbons as mentioned above The temperature of the captured liquid is different, so the second compressor 12 is used to lower the temperature uniformly to ensure that the temperature of the second liquid capture medium sprayed by the second spray tower reaches -120°C or -135°C, thereby ensuring a higher carbon capture rate.

A carbon capture system proposed in this application uses spray tower equipment to directly spray carbon capture liquid to the pre-cooled flue gas, and uses carbon capture liquid to desublimate and capture carbon dioxide gas, and the dry ice formed by sublimation It is taken out of the spray tower equipment by the carbon capture liquid, which avoids the collection difficulties caused by the condensation of dry ice on the wall of the spray tower equipment, and the dry ice layer affects heat conduction and other problems; moreover, by using the first spray tower and the second spray tower in series In the shower tower, the first spray tower and the second spray tower use carbon capture liquids of different temperatures to capture the carbon dioxide in the flue gas in stages, which not only improves the carbon capture rate but also reduces the cooling capacity consumption. And it enables the entire carbon capture system to select different capture methods of carbon capture rates according to actual needs; moreover, by setting the main heat exchanger, the flue gas can be pre-cooled, and the flue gas and liquid after carbon removal The carbon dioxide is recovered as cold energy, and a high-concentration carbon dioxide liquid is provided at the end, which is convenient for storage.

To sum up, this embodiment proposes a carbon capture system, which uses the main heat exchanger installed in the carbon capture system to pre-cool the flue gas dehydrated by the drying tower, which is similar to the use of carbon capture liquid in the related technology. The desublimation process of high-temperature flue gas will cause a large amount of evaporation of carbon capture liquid. Before the flue gas enters the spray tower equipment, the main heat exchanger is used to pre-cool the flue gas to reduce the risk of entering the spray tower equipment. The temperature of the flue gas reduces the temperature of the flue gas entering the spray tower equipment, and the flue gas with reduced temperature is cooled to the desublimation temperature of carbon dioxide by the carbon capture liquid. The temperature difference of the liquid is reduced, which can reduce the evaporation of the flue gas to the carbon capture liquid; moreover, use the spray tower equipment to collect the dry ice after the condensation of carbon dioxide in the flue gas, and avoid the use of box-type low-temperature carbon capture equipment as much as possible During the dry ice capture process, the dry ice condenses on the inner wall of the box-type low-temperature carbon capture equipment, resulting in difficulties in dry ice collection, corrosion of equipment, and poor thermal conductivity.

The above is only a specific implementation of the application, but the scope of protection of the application is not limited thereto. Anyone familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the application. Should be covered within the protection scope of this application. Therefore, the protection scope of the present application should be determined by the protection scope of the claims.

Claims (10)

1. A carbon capture system, comprising: a drying tower, a main heat exchanger, a spray tower device and a carbon trapping liquid supply device;

the drying tower, the main heat exchanger, the spray tower equipment and the carbon capture liquid supply equipment are connected in sequence;

the flue gas dehydrated by the drying tower enters the main heat exchanger, the main heat exchanger performs precooling treatment on the flue gas, the flue gas after precooling treatment enters the spray tower equipment, the carbon trapping liquid in the spray tower equipment is input into the spray tower equipment by the carbon trapping liquid supply equipment for cooling, carbon dioxide in the flue gas is cooled to the sublimation temperature of the carbon dioxide to obtain dry ice, the dry ice is liquefied to obtain liquid carbon dioxide, and the liquid carbon dioxide passes through the main heat exchanger to obtain high-concentration liquid carbon dioxide for storage.

2. The carbon capture system of claim 1, wherein the carbon capture fluid comprises: a first liquid trapping medium and a second liquid trapping medium; the dry ice comprises: a first portion of dry ice and a second portion of dry ice;

the spray tower apparatus comprises: a first spray tower and a second spray tower;

the first spray tower is respectively connected with the main heat exchanger and the second spray tower, and the first spray tower and the second spray tower are respectively connected with the carbon trapping liquid supply equipment;

the pre-cooled flue gas enters a first spray tower, a first liquid trapping medium with a first temperature is input into the first spray tower by the carbon trapping liquid supply device in the first spray tower to cool, carbon dioxide in the flue gas is cooled to the sublimation temperature of the carbon dioxide to obtain a first part of dry ice and cold flue gas, the first part of dry ice is liquefied to obtain liquid carbon dioxide of the first part of dry ice, the liquid carbon dioxide of the first part of dry ice passes through the main heat exchanger to obtain high-concentration liquid carbon dioxide, and the cold flue gas is input into a second spray tower;

the cold flue gas enters the second spray tower, the second liquid trapping medium with a second temperature is input into the second spray tower by the carbon trapping liquid supply device in the second spray tower for cooling, carbon dioxide in the cold flue gas is cooled to the sublimation temperature of the carbon dioxide, so as to obtain second part of dry ice, the second part of dry ice is liquefied to obtain liquid carbon dioxide of the second part of dry ice, and the liquid carbon dioxide of the second part of dry ice passes through the main heat exchanger to obtain high-concentration liquid carbon dioxide; wherein the first temperature is higher than the second temperature.

3. The carbon capture system of claim 2, further comprising: a chimney connected to the primary heat exchanger;

the second spray tower can obtain the second part of dry ice and also obtain the flue gas after the carbon trapping operation, and the flue gas after the carbon trapping operation is discharged by the second spray tower and then is discharged from the chimney after the heat exchange operation of the main heat exchanger;

and the main heat exchanger carries out heat exchange operation on the flue gas passing through the carbon trapping operation, recovers cold energy carried by the flue gas after the carbon trapping operation, and the recovered cold energy is used for carrying out precooling treatment on the flue gas dehydrated by the drying tower.

4. The carbon capture system of claim 2, wherein the carbon capture liquid supply apparatus comprises: a first refrigeration heat exchanger 8 and a second refrigeration heat exchanger 13;

the first refrigeration heat exchanger is connected with the first spray tower; the second refrigeration heat exchanger is connected with the second spray tower;

the first refrigeration heat exchanger is capable of inputting a first liquid trapping medium with a first temperature to the first spray tower;

the second refrigeration heat exchanger is capable of inputting a second liquid capture medium having a second temperature to the second spray tower.

5. The carbon capture system of claim 4, further comprising: a circulation pump, a solid-liquid separator, and a melting pump;

the circulating pump is respectively connected with the first spray tower, the second spray tower and the solid-liquid separator; the solid-liquid separator is also connected with the first refrigeration heat exchanger and the melting pump; the melting pump is also connected with the main heat exchanger;

the mixture of the dry ice and the carbon capture liquid flows out from the bottom of the first spray tower and the bottom of the second spray tower respectively, enters a solid-liquid separator for solid-liquid separation after passing through a circulating pump, and is separated from the mixture of the dry ice and the carbon capture liquid;

the separated dry ice is conveyed into the melting pump, the liquid carbon dioxide is obtained after the temperature is raised and liquefied by the melting pump, and the liquid carbon dioxide enters the main heat exchanger and is obtained after the cold energy of the main heat exchanger is recovered;

the separated carbon capture liquid is input into the first refrigeration heat exchanger, cooled to a first temperature by the first refrigeration heat exchanger, and then conveyed into the first spray tower to sublimate the flue gas in the first spray tower.

6. The carbon capture system of claim 5, wherein the primary heat exchanger exchanges heat with the passing liquid carbon dioxide, recovers cold energy carried in the liquid carbon dioxide by way of the exchange operation, and the recovered cold energy is used for pre-cooling flue gas dehydrated by the drying tower.

7. The carbon capture system of claim 5, wherein the solid-liquid separator separates the dry ice and the carbon capture fluid from the mixture of dry ice and the carbon capture fluid by rolling.

8. The carbon capture system of claim 4, wherein a carbon capture liquid make-up inlet is provided on the second refrigeration heat exchanger.

9. The carbon capture system of claim 4, further comprising: a first compressor, a second compressor, a first throttle valve, and a second throttle valve;

the first compressor and the first throttle valve are connected with each other and are respectively connected with the first refrigeration heat exchanger;

the second compressor and the second throttle valve are connected with each other and are respectively connected with the second refrigeration heat exchanger.

10. The carbon capture system of any one of claims 1-9, wherein the carbon capture fluid is an isopentane fluid or an isopentane-n-pentane mixed fluid.