A carbon capture absorber, system and method for escaped amine recovery and water balance control

Abstract

The present invention discloses a carbon capture absorption tower, system and method for fugitive amine recovery and water balance control, belonging to the field of greenhouse gas treatment technology. The carbon capture absorption tower comprises a tower body, in which an absorption layer, a temperature control layer, a primary amine recovery layer and a secondary amine recovery layer are arranged from bottom to top. The absorption tower of the present invention integrates the absorption layer, the temperature control layer, the primary amine recovery layer and the secondary amine recovery layer, and can effectively recover the moisture and amine components in the flue gas. By setting the temperature control layer and using the recovery liquid produced by the primary amine recovery layer and the secondary amine recovery layer as the temperature control washing liquid sprayed in the temperature control layer, the fugitive amine components and moisture in the absorbent are replenished, and the flue gas temperature of the temperature control layer is also reduced, and the escape of amines is reduced. The present invention can effectively reduce the amount of absorbent replenishment in the carbon capture process, greatly reducing the loss of the absorbent and the operating cost as well as the environmental impact caused by the escape of amines.

Description

Technical Field

[0001] The present invention belongs to the technical field of greenhouse gas treatment, and in particular relates to a carbon capture absorption tower, system and method for escaping amine recovery and water balance control. Background Art

[0002] The large-scale emission of carbon dioxide has led to the problem of global warming. Carbon dioxide capture technology is one of the key technologies to reduce carbon emissions. At present, the amine absorption method is the most mature and widely used carbon capture technology. Amine molecules react chemically with carbon dioxide in the absorption tower to absorb carbon dioxide in the raw gas, and the decarbonized flue gas is discharged from the top of the absorption tower. The absorption liquid is then heated and regenerated in the desorption tower to separate carbon dioxide from the absorbent. The main problem of the amine absorption method is the high regeneration energy consumption. Related studies have used amine components with low regeneration energy consumption but high volatility, such as 2-amino-2-methyl-1-propanol (AMP) and diethylethanolamine (DEEA), or used low-water absorbents with high amine concentrations, such as diethylethanolamine (DEEA) and hydroxyethylethylenediamine (AEEA) two-phase absorbents, diethylethanolamine (DEEA) and 3-methylaminopropylamine (MAPA) and other solvents or their mixed systems.

[0003] While these new absorbents reduce energy consumption, they also bring about a new problem of amine volatilization and escape, that is, the amine components are easily volatile and are carried away from the capture device into the atmosphere by the flue gas, which not only causes the loss of amine components, but also affects environmental safety. In addition, since the temperature of the flue gas increases after decarbonization in the absorption tower, the water content in the flue gas increases after decarbonization, causing the water content in the amine absorbent to decrease, affecting the performance of the absorbent. Therefore, the stable operation of the carbon capture system also requires the control of water balance. Existing research focuses on reducing the amine components that escape into the atmosphere, but does not recover the amine components and moisture. Therefore, it is necessary to find a system and method that can recover and balance the escaped amine components and moisture. Summary of the invention

[0004] In order to overcome the problems existing in the above-mentioned prior art, one of the objects of the present invention is to provide a carbon capture absorber for recovery of escaped amine and water balance control, which can recover and balance the escaped amine components and moisture, so as to achieve the purpose of reducing amine loss and maintaining the water balance of the amine absorbent.

[0005] A second object of the present invention is to provide a carbon capture system comprising the above-mentioned carbon capture absorption tower.

[0006] A third object of the present invention is to provide a carbon capture method using the above carbon capture system.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A first aspect of the present invention provides a carbon capture absorption tower for escape amine recovery and water balance control, comprising a tower body, wherein an absorption layer, a temperature control layer, a primary amine recovery layer and a secondary amine recovery layer are arranged in the tower body from bottom to top;

[0009] The absorption layer is provided with a flue gas inlet, a lean liquid inlet and a rich liquid outlet; the temperature control layer is provided with a temperature control water inlet; the primary amine recovery layer includes a primary packing layer, and is provided with a primary water inlet and a primary water outlet; the secondary amine recovery layer includes a secondary packing layer, and is provided with a secondary water inlet, a secondary water outlet and a tail gas outlet;

[0010] The lean liquid inlet is used to introduce the absorbent, and the flue gas inlet is used to introduce the flue gas. The flue gas passes through the absorption layer to form decarbonized flue gas, and the decarbonized flue gas enters the temperature control layer, the primary amine recovery layer and the secondary amine recovery layer in sequence, and is finally discharged from the tail gas outlet;

[0011] The temperature-controlled water inlet is connected with the primary water outlet and the secondary water outlet respectively; the temperature-controlled water inlet is used to introduce temperature-controlled washing liquid, and the temperature-controlled washing liquid is used to reduce the temperature of the decarbonized flue gas; the primary water inlet is used to introduce primary washing liquid, and the formed primary recovery liquid is discharged through the primary water outlet, and part of the primary recovery liquid enters the temperature control layer through the temperature-controlled water inlet as temperature-controlled washing liquid; the secondary water inlet is used to introduce secondary washing liquid, and the formed secondary recovery liquid is discharged through the secondary water outlet, and part of the secondary recovery liquid enters the temperature control layer through the temperature-controlled water inlet as temperature-controlled washing liquid.

[0012] In some specific embodiments of the present invention, the primary water outlet is also connected to the primary water inlet through a first pipe, and a primary water washing pump and a primary water washing cooler are provided on the first pipe; the primary water outlet is connected to the temperature control water inlet through a second pipe, and a primary water washing pump, a primary water washing cooler and a primary water return valve are provided on the second pipe; after the primary recovery liquid is discharged through the primary water outlet, a part of the primary recovery liquid returns to the primary amine recovery layer through the first pipe, and another part of the primary recovery liquid enters the temperature control layer through the second pipe;

[0013] The secondary water outlet is also connected to the secondary water inlet through a third pipe, and a secondary water washing pump and a secondary water washing cooler are arranged on the third pipe; the secondary water outlet is connected to the temperature control water inlet through a fourth pipe, and a secondary water washing pump, a secondary water washing cooler and a secondary water return valve are arranged on the fourth pipe; after the secondary recovery liquid is discharged through the secondary water outlet, a part of the secondary recovery liquid returns to the secondary amine recovery layer through the third pipe, and another part of the secondary recovery liquid enters the temperature control layer through the fourth pipe.

[0014] In some specific embodiments of the present invention, the temperature-controlled water inlet is also connected to a water replenishment valve through a fifth pipe, and the water replenishment valve is used to supply replenishment water to the temperature-controlled layer.

[0015] In some specific embodiments of the present invention, a lean liquid liquid distributor, a temperature-controlled liquid distributor, a primary liquid distributor and a secondary liquid distributor are further provided in the tower body and are respectively connected to the lean liquid inlet, the temperature-controlled water inlet, the primary water inlet and the secondary water inlet; a primary liquid collector and a secondary liquid collector are further provided in the tower body and are respectively connected to the primary water outlet and the secondary water outlet; the temperature-control layer and the absorption layer are interconnected.

[0016] In some specific embodiments of the present invention, the absorption layer also includes an intermediate liquid collector and an intermediate liquid distributor arranged from top to bottom in the tower body, the intermediate liquid collector and the intermediate liquid distributor are located between the lean liquid inlet and the rich liquid outlet, the intermediate liquid collector and the intermediate liquid distributor are connected through a sixth pipeline, an intermediate cooling pump and an intermediate cooler are provided on the sixth pipeline, the intermediate liquid collector is used to collect the heated absorbent, and after cooling through the sixth pipeline, it is passed into the intermediate liquid distributor.

[0017] The second aspect of the present invention provides a carbon capture system for escaping amine recovery and water balance control, comprising a desorption tower and an absorption tower according to any one of claims 1 to 5; the desorption tower comprises a product gas outlet, the product gas outlet is connected to the temperature control water inlet through a seventh pipeline, a condensation recovery device is provided on the seventh pipeline, the product gas generated by the desorption tower is discharged through the product gas outlet, and a condensation separation recovery liquid is formed through the condensation recovery device, and the condensation separation recovery liquid enters the temperature control layer through the temperature control water inlet as a temperature control washing liquid.

[0018] The third aspect of the present invention provides a carbon capture method for recovery of escaped amine and water balance control, which is implemented using the carbon capture system described in the second aspect of the present invention, and comprises the following steps:

[0019] S1, introducing flue gas into the flue gas inlet, introducing absorbent into the lean liquid inlet, the flue gas and the absorbent contacting each other to generate a decarbonization reaction, thereby forming decarbonized flue gas and rich liquid, the decarbonized flue gas entering the temperature control layer, and the rich liquid being discharged from the rich liquid outlet;

[0020] S2, introducing a temperature-control washing liquid into the temperature-control inlet, the decarbonized flue gas enters the temperature-control layer, contacts with the temperature-control washing liquid, and then enters the primary amine recovery layer; the temperature-control washing liquid contacts with the decarbonized flue gas and then enters the absorption layer to achieve the recovery of the absorbent and the replenishment of water;

[0021] S3, using method S3-1 or method S3-2;

[0022] Method S3-1 is: a primary water washing liquid is introduced into the primary water inlet, the decarbonized flue gas enters the primary amine recovery layer, contacts with the primary washing liquid at the primary packing layer, and then enters the secondary amine recovery layer; the primary washing liquid contacts with the decarbonized flue gas to form a primary recovery liquid, and part of the primary recovery liquid is introduced into the temperature control layer as a temperature control washing liquid;

[0023] Method S3-2 is: introducing a primary water wash liquid into the primary water inlet to wet the primary packing layer, then stopping introducing the primary water wash liquid, the decarbonized flue gas enters the primary amine recovery layer, contacts the wet primary packing layer, and then enters the secondary amine recovery layer;

[0024] S4. A secondary water washing liquid is introduced into the secondary water inlet, and the decarbonized flue gas enters the secondary amine recovery layer, contacts with the secondary washing liquid at the secondary packing layer, and then is discharged through the tail gas outlet; the secondary washing liquid contacts with the decarbonized flue gas to form a secondary recovery liquid, and part of the secondary recovery liquid is introduced into the temperature control layer as a temperature control washing liquid.

[0025] When the absorbent escapes mainly in gaseous form, step S3 adopts method S3-1; when the absorbent escapes mainly in aerosol form, step S3 adopts method S3-2.

[0026] In some specific embodiments of the present invention, in method S3-1, in the primary amine recovery layer, the ratio of the inlet flow rate of the primary water wash liquid to the inlet flow rate of the decarbonized flue gas is 1:(400-3000).

[0027] In some specific embodiments of the present invention, in step S4, in the secondary amine recovery layer, the ratio of the inlet flow rate of the secondary water wash liquid to the inlet flow rate of the decarbonized flue gas is 1:(400-3000).

[0028] In some specific embodiments of the present invention, the temperature of the flue gas is 30-50°C.

[0029] In some specific embodiments of the present invention, the temperature of the decarbonized flue gas after passing through the absorption layer is 60-70°C.

[0030] In some specific embodiments of the present invention, the temperature of the decarbonized flue gas after passing through the temperature control layer is 40-60°C.

[0031] In some specific embodiments of the present invention, the temperature of the decarbonized flue gas after passing through the primary amine recovery layer is 40-50°C.

[0032] In some specific embodiments of the present invention, the temperature of the decarbonized flue gas after passing through the secondary amine recovery layer is 35-40°C.

[0033] In some specific embodiments of the present invention, the amine concentration of the decarbonized flue gas after passing through the secondary amine recovery layer is ≤10 ppm.

[0034] The beneficial effects of the present invention are as follows: the absorption tower of the present invention integrates an absorption layer, a temperature control layer, a primary amine recovery layer and a secondary amine recovery layer, and can effectively recover moisture and amine components in flue gas. By setting a temperature control layer and using the recovery liquid produced by the primary amine recovery layer and the secondary amine recovery layer as the temperature control washing liquid sprayed in the temperature control layer, the escaping amine components and moisture in the absorbent are replenished, the flue gas temperature of the temperature control layer is lowered, and the escape of amines is reduced. The present invention can effectively reduce the amount of absorbent replenishment in the carbon capture process, greatly reducing the loss of the absorbent and the operating cost as well as the environmental impact caused by the escape of amines.

[0035] Specifically, compared with the prior art, the present invention has the following advantages:

[0036] 1. The amine recovery layer of the present invention can be used in a two-stage wet bed or a primary dry bed and a secondary wet bed to recover the amine components. The two-stage wet bed means that both the primary amine recovery layer and the secondary amine recovery layer are sprayed with washing liquid, and the amine components are recovered by two water washing sprays. The primary dry bed and the secondary wet bed means that the primary amine recovery layer is only sprayed with part of the washing liquid to obtain a wet primary filler layer as the primary dry bed, and the secondary amine recovery layer is sprayed with washing liquid as the secondary wet bed. The aerosol particles of the amine components grow larger in the space of the primary dry bed, and are more easily recovered by spraying a certain flow of water in the secondary wet bed. The specific amine recovery layer to be used needs to be determined according to the amine escape of the absorbent. The primary dry bed and the secondary wet bed are for amine escape mainly in the form of aerosol, and the secondary wet bed is for amine escape mainly in the form of gaseous emission. The amine recovery layer of the present invention is compatible with the settings of the two-stage wet bed and the primary dry bed and the secondary wet bed, and can adapt to more types of absorbents and more complex working conditions.

[0037] 2. The carbon capture system of the present invention is also provided with a treatment for the condensed separation recovery liquid generated during the condensation recovery of the desorption tower product gas, and the condensed separation recovery liquid is transported to the temperature control layer for spraying instead of the traditional method (recovery to the desorption tower). In addition, the liquid separated by the gas-liquid separator after the carbon dioxide compression precooler also enters the temperature control layer. The low-temperature condensed separation recovery liquid of the desorption tower product gas is transported to the amine recovery liquid instead of being sent to the desorption tower, saving heat consumption.

[0038] 3. The spray water of the amine recovery layer of the absorption tower and the low-temperature condensation separation recovery liquid of the desorption tower product gas of the present invention are both recycled to control the temperature layer spray liquid, which is beneficial to the water balance control of the system and improves the reliability of the system operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A carbon capture system for escape amine recovery and water balance control is provided for embodiments of the present invention.

[0040] Among them: Among them: 100-absorption tower; 110-tower body; 120-absorption layer; 121-flue gas inlet; 122-lean liquid inlet; 123-rich liquid outlet; 124-lean liquid distributor; 125-intermediate liquid collector; 126-intermediate liquid distributor; 127-intermediate cooling pump; 128-intermediate cooler; 129-first absorption packing layer; 1210-second absorption packing layer; 130-temperature control layer; 131 - temperature-controlled water inlet; 132-temperature-controlled liquid distributor; 133-temperature-controlled packing layer; 140-primary amine recovery layer; 141-primary packing layer; 142-primary water inlet; 143-primary water outlet; 144-primary water wash pump; 145-primary water wash cooler; 146-primary return valve; 147-primary liquid distributor; 148-primary liquid collector; 150-secondary amine recovery layer; 151-secondary packing layer; 1 52-secondary water inlet; 153-secondary water outlet; 154-secondary water wash pump; 155-secondary water wash cooler; 156-secondary return valve; 157-secondary liquid distributor; 158-secondary liquid collector; 159-tail gas outlet; 161-water replenishment valve; 162-rich liquid pump; 163-lean and rich liquid heat exchanger; 164-liquid storage tank; 165-feed pump; 166-feed cooler; 167-amine replenishment valve; 200 -desorption tower; 210-first liquid distributor of desorption tower; 220-second liquid distributor of desorption tower; 230-liquid collector of desorption tower; 240-product gas outlet; 250-condensation recovery device; 251-condenser; 252-first gas-liquid separator; 253-reflux pump; 254-carbon dioxide compression precooler; 255-second gas-liquid separator; 261-reboiler; 262-bottom of desorption tower; 263-lean liquid pump. DETAILED DESCRIPTION

[0041] The content of the present invention is further described in detail below through specific examples. It should also be understood that the following examples are only used to further illustrate the present invention and cannot be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the principles set forth in the present invention all belong to the scope of protection of the present invention. The specific process parameters and the like in the following examples are also only examples within a suitable range, that is, those skilled in the art can make a selection within a suitable range through the description herein, and are not limited to the specific data exemplified below. The raw materials, reagents or devices used in the following examples and comparative examples, unless otherwise specified, can all be obtained from conventional commercial sources, or can be obtained by existing known methods.

[0042] like Figure 1As shown, an embodiment of the present invention provides a carbon capture system for escape amine recovery and water balance control, including an absorption tower 100 and a desorption tower 200 .

[0043] In some embodiments of the present invention, the absorption tower 100 includes: a tower body 110, in which an absorption layer 120, a temperature control layer 130, a primary amine recovery layer 140 and a secondary amine recovery layer 150 are arranged from bottom to top; the absorption layer 120 is provided with a flue gas inlet 121, a lean liquid inlet 122 and a rich liquid outlet 123; the temperature control layer 130 is provided with a temperature control water inlet 131; the primary amine recovery layer 140 includes a primary packing layer 141, and is provided with a primary water inlet 142 and a primary water outlet 143; the secondary amine recovery layer 150 includes a secondary packing layer 151, and is provided with a secondary water inlet 152, a secondary water outlet 153 and a tail gas outlet 159; the lean liquid inlet 122 is used to pass the absorbent, the flue gas inlet 121 is used to pass the flue gas, and the flue gas passes through the absorption layer 120 to form a degassing agent. The carbon flue gas and the decarbonized flue gas enter the temperature control layer 130, the primary amine recovery layer 140 and the secondary amine recovery layer 150 in sequence, and are finally discharged from the tail gas outlet 159; the temperature control water inlet 131 is connected with the primary water outlet 143 and the secondary water outlet 153 respectively; the temperature control water inlet 131 is used to pass the temperature control washing liquid, and the temperature control washing liquid is used to reduce the temperature of the decarbonized flue gas; the primary water inlet 142 is used to pass the primary washing liquid, and the formed primary recovery liquid is discharged through the primary water outlet 143, and part of the primary recovery liquid enters the temperature control layer 130 through the temperature control water inlet 131 as the temperature control washing liquid; the secondary water inlet 152 is used to pass the secondary washing liquid, and the formed secondary recovery liquid is discharged through the secondary water outlet 153, and part of the secondary recovery liquid enters the temperature control layer 130 through the temperature control water inlet 131 as the temperature control washing liquid.

[0044] In some embodiments of the present invention, a demister is further provided at the tail gas outlet 159 at the top of the absorption tower. The demister is used to reduce the tiny droplets entrained by the flue gas and can be provided according to actual needs.

[0045] In some embodiments of the present invention, the primary water outlet 143 is also connected to the primary water inlet 142 through a first pipe, and a primary water washing pump 144 and a primary water washing cooler 145 are provided on the first pipe; the primary water outlet 143 is connected to the temperature control water inlet 131 through a second pipe, and a primary water washing pump 144, a primary water washing cooler 145 and a primary return valve 146 are provided on the second pipe; after the primary recovery liquid is discharged through the primary water outlet 143, a part of the primary recovery liquid returns to the primary amine recovery layer 140 through the first pipe, and another part of the primary recovery liquid enters the temperature control layer 130 through the second pipe.

[0046] In some embodiments of the present invention, the secondary water outlet 153 is also connected to the secondary water inlet 152 through a third pipe, and a secondary water washing pump 154 ​​and a secondary water washing cooler 155 are provided on the third pipe; the secondary water outlet 153 is connected to the temperature control water inlet 131 through a fourth pipe, and a secondary water washing pump 154, a secondary water washing cooler 155 and a secondary return valve 156 are provided on the fourth pipe; after the secondary recovery liquid is discharged through the secondary water outlet 153, a part of the secondary recovery liquid returns to the secondary amine recovery layer 150 through the third pipe, and another part of the secondary recovery liquid enters the temperature control layer 130 through the fourth pipe.

[0047] In some embodiments of the present invention, the temperature control water inlet 131 is also connected to the water replenishment valve 161 through a fifth pipe, and the water replenishment valve 161 is used to supply replenishing water to the temperature control layer 130.

[0048] In some embodiments of the present invention, a lean liquid liquid distributor 124, a temperature-controlled liquid distributor 132, a primary liquid distributor 147 and a secondary liquid distributor 157 are also provided in the tower body and are respectively connected to the lean liquid inlet 122, the temperature-controlled water inlet 131, the primary water inlet 142 and the secondary water inlet 152; a primary liquid collector 148 and a secondary liquid collector 158 are also provided in the tower body and are respectively connected to the primary water outlet 143 and the secondary water outlet 153; the temperature control layer 130 and the absorption layer 120 are interconnected.

[0049] In some embodiments of the present invention, the absorption layer 120 also includes an intermediate liquid collector 125 and an intermediate liquid distributor 126 arranged from top to bottom in the tower body. The intermediate liquid collector 125 and the intermediate liquid distributor 126 are located between the lean liquid inlet 122 and the rich liquid outlet 123. The intermediate liquid collector 125 and the intermediate liquid distributor 126 are connected through a sixth pipeline. An intermediate cooling pump 127 and an intermediate cooler 128 are provided on the sixth pipeline. The intermediate liquid collector 125 is used to collect the heated absorbent, and after cooling through the sixth pipeline, it is passed into the intermediate liquid distributor 126.

[0050] In some embodiments of the present invention, a first absorption filler layer 129 is disposed between the lean liquid distributor 124 and the intermediate liquid collector 125 , and a second absorption filler layer 1210 is disposed between the intermediate liquid distributor 126 and the rich liquid outlet 123 .

[0051] In some embodiments of the present invention, a temperature-controlling filler layer 133 is further disposed below the temperature-controlling liquid distributor 132 .

[0052] In some embodiments of the present invention, the rich liquid outlet 123 is connected to the lean liquid inlet 122 via a rich liquid pump 162, a lean-rich liquid heat exchanger 163, a liquid storage tank 164, a feed pump 165 and a feed cooler 166 in sequence; the liquid storage tank 164 is also connected to an amine replenishment valve 167, which is used to replenish amine components to the liquid storage tank 164.

[0053] In some embodiments of the present invention, the desorption tower 200 includes: a first liquid distributor 210 for the desorption tower, a second liquid distributor 220 for the desorption tower, a liquid collector 230 for the desorption tower, a product gas outlet 240, and several packing layers; the product gas outlet 240 is connected to the temperature control water inlet 131 through a seventh pipe, and a condensation recovery device 250 is provided on the seventh pipe. The product gas generated by the desorption tower is discharged through the product gas outlet 240, and a condensation separation recovery liquid is formed through the condensation recovery device 250. The condensation separation recovery liquid enters the temperature control layer 130 through the temperature control water inlet 131 as a temperature control washing liquid.

[0054] In some embodiments of the present invention, the condensation recovery device 250 includes a condenser 251, a first gas-liquid separator 252, a reflux pump 253, a carbon dioxide compression precooler 254, and a second gas-liquid separator 255; the product gas outlet 240, the condenser 251, the first gas-liquid separator 252, the reflux pump 253 and the temperature control water inlet 131 are connected in sequence, the first gas-liquid separator 252 is connected with the carbon dioxide compression precooler 254, the second gas-liquid separator 255 and the reflux pump 253 in sequence, and the second gas-liquid separator 255 is also connected with the carbon dioxide compression system, and the separated carbon dioxide gas is introduced into the carbon dioxide compression system.

[0055] In some embodiments of the present invention, the desorption tower liquid collector 230 is connected to the reboiler 261 and the desorption tower bottom 262 in sequence, and the desorption tower bottom 262 is connected to the lean liquid pump 263, the lean and rich liquid heat exchanger 163, and the liquid storage tank 164 in sequence; the liquid collected by the desorption tower liquid collector 230 contains some amine components, and the amine components are recovered through this route.

[0056] The embodiment of the present invention further provides a carbon capture method for recovery of escaped amine and water balance control, which is implemented by using the aforementioned carbon capture system and comprises the following steps:

[0057] S1. Flue gas is introduced into the flue gas inlet 121, and absorbent is introduced into the lean liquid inlet 122. The flue gas and the absorbent come into contact with each other to cause a decarbonization reaction, thereby forming decarbonized flue gas and rich liquid. The decarbonized flue gas enters the temperature control layer 130, and the rich liquid is discharged from the rich liquid outlet 123.

[0058] S2, introducing temperature-controlled washing liquid into the temperature-controlled water inlet 131, the decarbonized flue gas enters the temperature-controlled layer 130, contacts with the temperature-controlled washing liquid, and then enters the primary amine recovery layer 140; the temperature-controlled washing liquid contacts with the decarbonized flue gas and then enters the absorption layer 130, realizing the recovery of the absorbent and the replenishment of water;

[0059] S3, using method S3-1 or method S3-2;

[0060] Method S3-1 is as follows: a primary water washing liquid is introduced into the primary water inlet 142, and the decarbonized flue gas enters the primary amine recovery layer 140, contacts with the primary washing liquid at the primary packing layer 141, and then enters the secondary amine recovery layer 150; the primary washing liquid contacts with the decarbonized flue gas to form a primary recovery liquid, and part of the primary recovery liquid is introduced into the temperature control layer 130 as a temperature control washing liquid;

[0061] Method S3-2 is: introducing a primary water wash liquid into the primary water inlet 142 to wet the primary packing layer 141, then stopping introducing the primary water wash liquid, and the decarbonized flue gas enters the primary amine recovery layer 140, contacts the wet primary packing layer 141, and then enters the secondary amine recovery layer 150;

[0062] S4. Secondary water washing liquid is introduced into the secondary water inlet 152, and the decarbonized flue gas enters the secondary amine recovery layer 150, contacts with the secondary washing liquid at the secondary packing layer 151, and then is discharged through the tail gas outlet 159; the secondary washing liquid contacts with the decarbonized flue gas to form a secondary recovery liquid, and part of the secondary recovery liquid is introduced into the temperature control layer 130 as a temperature control washing liquid.

[0063] In the above methods, the primary amine recovery layer and the secondary amine recovery layer of method S3-1 both use wet beds to recover amine components, i.e., the amine components are recovered through two-stage wet beds; the primary amine recovery layer of method S3-2 uses a dry bed to recover amine components, and the secondary amine recovery layer uses a wet bed to recover amine components, i.e., the amine components are recovered through a primary dry bed and a primary wet bed. For some amine components, when the primary water washing liquid is only used to wet the primary packing layer, and the amine components are recovered using a dry bed containing a wet primary packing layer, the aerosol particles of the amine components grow larger in the space of the dry bed, and are more easily recovered in the secondary amine recovery layer by spraying with a certain flow of water.

[0064] In some embodiments of the present invention, when the absorbent escapes mainly in gaseous form, step S3 adopts method S3-1; when the absorbent escapes mainly in aerosol form, step S3 adopts method S3-2.

[0065] The mechanism of amine escape is relatively complex and is greatly affected by factors such as flue gas conditions, operating conditions and the chemical structure of amine molecules. There are generally two forms of escape, gaseous escape and aerosol escape. When gaseous escape is the main form of escape, two-stage water washing is used, namely method S3-1. When aerosol escape is the main form of escape, a first-stage dry bed and a second-stage wet bed are used, namely method S3-2. In the actual production process, it is necessary to monitor the flue gas and adjust the selection of method S3-1 or method S3-2 based on the monitoring results.

[0066] In some non-limiting examples of the present invention, absorbents that tend to escape mainly in gaseous form include N-methyldiethanolamine (MDEA), diethylaminoethanol (DEEA), and the like.

[0067] In some non-limiting examples of the present invention, absorbents that tend to escape primarily in the form of aerosols include ethanolamine (MEA), 2-amino-2-methyl-1-propanol (AMP), and the like.

[0068] In some embodiments of the present invention, in method S3-1, in the primary amine recovery layer, the ratio of the inlet flow rate of the primary water wash liquid to the inlet flow rate of the decarbonized flue gas is 1:(400-3000).

[0069] In some embodiments of the present invention, in step S4, in the secondary amine recovery layer, the ratio of the inlet flow rate of the secondary water washing liquid to the inlet flow rate of the decarbonized flue gas is 1:(400-3000).

[0070] The flow rate of the primary washing liquid and the secondary washing liquid will affect the amine recovery effect. Generally, as the flow rate of the washing liquid increases, the amine recovery effect improves, but the marginal effect decreases. After reaching a certain flow rate, it is difficult to improve the amine recovery effect by further increasing it.

[0071] In some embodiments of the present invention, the flue gas is pretreated before being inlet, and the temperature of the flue gas is reduced by the pretreatment.

[0072] In some embodiments of the present invention, the temperature of the flue gas is 30-50°C; more specifically, 35-45°C; non-limiting examples include 38°C, 40°C or 42°C.

[0073] In some embodiments of the present invention, the temperature of the decarbonized flue gas after passing through the absorption layer is 60-70°C; more specifically, 62-68°C; non-limiting examples are 64°C, 65°C or 66°C.

[0074] In some embodiments of the present invention, the temperature of the decarbonized flue gas after passing through the temperature control layer is 50-60°C; more specifically, 52-58°C; non-limiting examples are 54°C, 55°C or 56°C.

[0075] In some embodiments of the present invention, the temperature of the decarbonized flue gas after passing through the primary amine recovery layer is 40-50°C; non-limiting examples are 42°C, 45°C or 48°C.

[0076] In some embodiments of the present invention, the temperature of the decarbonized flue gas after passing through the secondary amine recovery layer is 35-40°C; non-limiting examples are 36°C, 37°C, 38°C or 39°C.

[0077] In some embodiments of the present invention, the amine concentration of the decarbonized flue gas after passing through the secondary amine recovery layer is ≤10 ppm.

[0078] In some embodiments of the present invention, the temperature control washing liquid of the temperature control layer is composed of three parts. The first part is the primary recovery liquid and the secondary recovery liquid from the primary amine recovery layer and the secondary amine recovery layer, which recover the amine components and moisture carried in the decarbonized flue gas into the washing water and are used for spraying into the temperature control layer, so as to replenish the escaped amine components and moisture in the absorbent, reduce the flue gas temperature of the temperature control layer, and reduce the escape of amines; the second part is the condensation separation recovery liquid obtained by separation from the condensation recovery device including the first gas-liquid separator and the second gas-liquid separator, and this part of the liquid is mainly water and a certain amount of amines; the third part is the distribution of supplementary water introduced from the water replenishment valve.

[0079] The invention is further described below in conjunction with more specific embodiments.

[0080] In the following examples, the overall amine recovery is obtained by the following steps:

[0081] First, the amine concentration in the decarbonized flue gas coming out of the absorption layer 120 is measured, recorded as C1, and then the amine concentration in the flue gas coming out of the tail gas outlet 159 is measured, recorded as C2, and finally the overall amine recovery rate is calculated according to the following formula: Overall amine recovery rate = (C1-C2) / C1×100%.

[0082] Example 1

[0083] A carbon capture method for fugitive amine recovery and water balance control using Figure 1 The carbon capture system shown in the figure is realized. In this example, the absorbent used is diethylaminoethanol containing volatile amines. The specific steps include:

[0084] (1) The flue gas from a coal-fired power plant is cooled to about 40°C by a pretreatment tower, and the saturated wet flue gas formed enters the absorption layer 120 in the absorption tower 100. The feed pump 165 cools the absorbent drawn from the liquid storage tank 164 to 40°C by the feed cooler 166 and then sprays it into the absorption layer 120 in the absorption tower 100. The CO2 in the flue gas reacts with the absorbent. The heat released by the reaction increases the temperature of the flue gas and the absorbent. The CO2 in the flue gas is absorbed by the absorbent to form decarbonized flue gas, and the temperature rises to about 65°C. The increase in temperature causes the flue gas to take away additional moisture and amine components from the absorbent. Next, the decarbonized flue gas enters the temperature control layer 130.

[0085] (2) After the decarbonized flue gas comes out of the absorption layer 120, it enters the temperature control layer 130, and the temperature control layer 130 sprays a low-temperature temperature control washing liquid (the temperature control washing liquid contains amine components, which is an amine recovery liquid, including a primary water washing liquid, a secondary water washing liquid, a condensation separation liquid and a small amount of water supplement). The temperature control washing liquid and the decarbonized flue gas are contacted in the temperature control filler layer 133 through spraying, so that the temperature of the decarbonized flue gas drops to about 55°C. The temperature control washing liquid enters the absorption layer 120 at the same time and mixes with the sprayed lean liquid, realizing the recovery of amines and the supplement of water, so that the composition of the absorbent remains stable. The temperature control layer 130 can reduce the amine concentration in the flue gas by about 30-40%.

[0086] (3) Then the decarbonized flue gas enters the primary amine recovery layer 140, and the washing water as the primary washing liquid is sprayed by the primary liquid distributor 147 to contact and react with the decarbonized flue gas in the primary packing layer 141. The ratio of flue gas flow rate to primary washing liquid flow rate is 700:1. The amine components and water vapor in the flue gas are absorbed by the washing water. At the same time, the washing water temperature rises and the washing water falls into the primary liquid collector 148 to form a primary recovery liquid. The primary water washing pump 144 pumps the primary recovery liquid into the primary water washing cooler 145 for cooling and then sprays it again through the primary liquid distributor 147 for water washing. The excess of the primary recovery liquid becomes the temperature control washing liquid and is transported to the temperature control layer 130 through the primary return valve 146. At this stage, the temperature of the decarbonized flue gas drops to 40-50°C, and the amine concentration in the flue gas can be further reduced by about 75-85%.

[0087] (4) Then the decarbonized flue gas enters the secondary amine recovery layer 150, and the washing water as the secondary washing liquid is sprayed by the secondary liquid distributor 157 to contact and react with the decarbonized flue gas in the secondary packing layer 151. The ratio of flue gas flow rate to secondary washing liquid flow rate is 1000:1. Most of the amines and their degradation products in the decarbonized flue gas are absorbed by the secondary washing liquid, and the secondary washing liquid falls into the secondary liquid collector 158 to form a secondary recovery liquid. The secondary water washing pump 154 ​​pumps the secondary recovery liquid into the secondary water washing cooler 155. Part of the secondary recovery liquid is sprayed again through the secondary liquid distributor 157 for water washing. The excess part becomes the temperature control washing liquid and is transported to the temperature control layer 130 through the secondary return valve 156. At this stage, the temperature of the decarbonized flue gas drops to 35-40°C, and the amine concentration in the flue gas can be further reduced by 70-80%, so that the amine concentration is controlled below 10ppm.

[0088] (5) The decarbonized flue gas is then discharged from the tail gas outlet 159 at the top of the absorption tower. As a result, most of the amine components and water carried in the decarbonized flue gas are recovered. The above-mentioned carbon capture method of fugitive amine recovery and water balance control achieves the benefits of water replenishment, recovery of amine components in the absorbent and pollution reduction, and the overall amine recovery rate reaches more than 95%.

[0089] Example 2

[0090] A carbon capture method for fugitive amine recovery and water balance control using Figure 1 The carbon capture system shown in the figure is implemented. In this example, the absorbent used is a small molecule amine 2-amino-2-methyl-1-propanol or ethanolamine that is easy to generate aerosols, and includes the following steps:

[0091] (1) The flue gas from a coal-fired power plant is cooled to about 40°C by a pretreatment tower, and the saturated wet flue gas formed enters the absorption layer 120 in the absorption tower 100. The feed pump 165 cools the absorbent drawn from the liquid storage tank 164 to 40°C by the feed cooler 166 and then sprays it into the absorption layer 120 in the absorption tower 100. The CO2 in the flue gas reacts with the absorbent. The heat released by the reaction increases the temperature of the flue gas and the absorbent. The CO2 in the flue gas is absorbed by the absorbent to form decarbonized flue gas, and the temperature rises to about 65°C. The increase in temperature causes the flue gas to take away additional moisture and amine components from the absorbent. Next, the decarbonized flue gas enters the temperature control layer 130.

[0092] (2) After the decarbonized flue gas comes out of the absorption layer 120, it enters the temperature control layer 130, and the temperature control layer 130 sprays a low-temperature temperature control washing liquid (the temperature control washing liquid contains amine components, which is an amine recovery liquid, including a primary water washing liquid, a secondary water washing liquid, a condensation separation collection liquid and a small amount of water supplement). The temperature control washing liquid and the decarbonized flue gas are contacted in the temperature control filler layer 133 through spraying, so that the temperature of the decarbonized flue gas drops to about 55°C. The temperature control washing liquid enters the absorption layer 120 at the same time and mixes with the sprayed lean liquid, realizing the recovery of amines and the supplement of water, so that the composition of the absorbent remains stable. The temperature control layer 130 can reduce the amine concentration in the flue gas by about 30-40%.

[0093] (3) The decarbonized flue gas then enters the primary amine recovery layer 140, at which time a small amount of washing water is sprayed to wet the surface of the primary packing layer 141, and the packing layer is used as a dry bed to provide space for the growth of amine component aerosol particles, which is convenient for removal in the secondary amine recovery layer 150.

[0094] (4) Then the decarbonized flue gas enters the secondary amine recovery layer 150. The washing water as the secondary washing liquid is sprayed by the secondary liquid distributor 157 and contacts the decarbonized flue gas in the secondary packing layer 151 for reaction. The ratio of flue gas flow rate to secondary washing liquid flow rate is 600:1. The amine components in the decarbonized flue gas become larger after the dry bed growth. The amine components are easily absorbed by the washing water. At the same time, the temperature of the decarbonized flue gas decreases. The moisture in the decarbonized flue gas enters the secondary washing liquid. The secondary washing liquid is collected by the secondary liquid collector 158 to form a secondary recovery liquid. The secondary water washing pump 154 ​​pumps the secondary recovery liquid into the secondary water washing cooler 155. Part of the secondary recovery liquid is sprayed again by the secondary liquid distributor 157 for water washing. The excess part becomes the temperature control washing liquid and is transported to the temperature control layer 130 through the secondary return valve 156. At this stage, the temperature of the flue gas after decarbonization drops to about 35-40°C. The amine concentration in the decarbonized flue gas can be further reduced by more than 90%, so that the amine concentration is controlled below 10ppm.

[0095] (5) The decarbonized flue gas is then discharged from the tail gas outlet 159 at the top of the absorption tower. As a result, most of the amine components and water carried in the decarbonized flue gas are recovered. The above-mentioned carbon capture method of fugitive amine recovery and water balance control achieves the benefits of water replenishment, recovery of amine components in the absorbent and pollution reduction, and the overall amine recovery rate reaches more than 95%.

[0096] By using the carbon capture method provided in the embodiment of the present invention, the amount of absorbent supplemented during the carbon capture process can be reduced by 20-70%.

[0097] In summary, the absorption tower of the present invention integrates an absorption layer, a temperature control layer, a primary amine recovery layer and a secondary amine recovery layer, and can effectively recover moisture and amine components in flue gas. By setting a temperature control layer and using the recovery liquid produced by the primary amine recovery layer and the secondary amine recovery layer as the temperature control washing liquid sprayed in the temperature control layer, the escaping amine components and moisture in the absorbent are replenished, and the flue gas temperature of the temperature control layer is also lowered, and the escape of amines is reduced. The present invention can effectively reduce the amount of absorbent replenishment in the carbon capture process, and greatly reduce the loss of absorbent and operating costs.

Claims

1. A carbon capture absorber for escape amine recovery and water balance control, characterized in that: It comprises a tower body, wherein the tower body is provided with an absorption layer, a temperature control layer, a primary amine recovery layer and a secondary amine recovery layer from bottom to top; The absorption layer is provided with a flue gas inlet, a lean liquid inlet and a rich liquid outlet; the temperature control layer is provided with a temperature control water inlet; the primary amine recovery layer includes a primary packing layer, and is provided with a primary water inlet and a primary water outlet; the secondary amine recovery layer includes a secondary packing layer, and is provided with a secondary water inlet, a secondary water outlet and a tail gas outlet; The lean liquid inlet is used to introduce the absorbent, and the flue gas inlet is used to introduce the flue gas. The flue gas passes through the absorption layer to form decarbonized flue gas, and the decarbonized flue gas enters the temperature control layer, the primary amine recovery layer and the secondary amine recovery layer in sequence, and is finally discharged from the tail gas outlet; The temperature-controlled water inlet is connected with the primary water outlet and the secondary water outlet respectively; the temperature-controlled water inlet is used to introduce temperature-controlled washing liquid, and the temperature-controlled washing liquid is used to reduce the temperature of the decarbonized flue gas; the primary water inlet is used to introduce primary washing liquid, and the formed primary recovery liquid is discharged through the primary water outlet, and part of the primary recovery liquid enters the temperature control layer through the temperature-controlled water inlet as temperature-controlled washing liquid; the secondary water inlet is used to introduce secondary washing liquid, and the formed secondary recovery liquid is discharged through the secondary water outlet, and part of the secondary recovery liquid enters the temperature control layer through the temperature-controlled water inlet as temperature-controlled washing liquid.

2. The absorption tower according to claim 1, characterized in that The primary water outlet is also connected to the primary water inlet through a first pipe, and a primary water washing pump and a primary water washing cooler are arranged on the first pipe; the primary water outlet is connected to the temperature control water inlet through a second pipe, and a primary water washing pump, a primary water washing cooler and a primary water return valve are arranged on the second pipe; after the primary recovery liquid is discharged through the primary water outlet, a part of the primary recovery liquid returns to the primary amine recovery layer through the first pipe, and another part of the primary recovery liquid enters the temperature control layer through the second pipe; The secondary water outlet is also connected to the secondary water inlet through a third pipe, and a secondary water washing pump and a secondary water washing cooler are arranged on the third pipe; the secondary water outlet is connected to the temperature control water inlet through a fourth pipe, and a secondary water washing pump, a secondary water washing cooler and a secondary water return valve are arranged on the fourth pipe; after the secondary recovery liquid is discharged through the secondary water outlet, a part of the secondary recovery liquid returns to the secondary amine recovery layer through the third pipe, and another part of the secondary recovery liquid enters the temperature control layer through the fourth pipe.

3. The absorption tower according to claim 1, characterized in that The temperature control water inlet is also connected to the water replenishment valve through a fifth pipeline, and the water replenishment valve is used to supply replenishment water to the temperature control layer.

4. The absorption tower according to claim 1, characterized in that The tower body is also provided with a lean liquid liquid distributor, a temperature-controlled liquid distributor, a primary liquid distributor and a secondary liquid distributor, which are respectively connected to the lean liquid inlet, the temperature-controlled water inlet, the primary water inlet and the secondary water inlet; the tower body is also provided with a primary liquid collector and a secondary liquid collector, which are respectively connected to the primary water outlet and the secondary water outlet; the temperature-control layer and the absorption layer are interconnected.

5. The absorption tower according to claim 1, characterized in that The absorption layer also includes an intermediate liquid collector and an intermediate liquid distributor arranged from top to bottom in the tower body, the intermediate liquid collector and the intermediate liquid distributor are located between the lean liquid inlet and the rich liquid outlet, the intermediate liquid collector and the intermediate liquid distributor are connected through a sixth pipeline, an intermediate cooling pump and an intermediate cooler are arranged on the sixth pipeline, the intermediate liquid collector is used to collect the heated absorbent, and after cooling through the sixth pipeline, pass into the intermediate liquid distributor.

6. A carbon capture system for escaped amine recovery and water balance control, characterized in that: It comprises a desorption tower and an absorption tower as claimed in any one of claims 1 to 5; the desorption tower comprises a product gas outlet, the product gas outlet is connected to the temperature-controlled water inlet through a seventh pipeline, a condensation recovery device is arranged on the seventh pipeline, the product gas generated by the desorption tower is discharged through the product gas outlet, a condensation separation recovery liquid is formed through the condensation recovery device, and the condensation separation recovery liquid enters the temperature control layer through the temperature control water inlet as a temperature-controlled washing liquid.

7. A carbon capture method for escaped amine recovery and water balance control, characterized in that: The method is implemented by using the carbon capture system according to claim 6, comprising the following steps: S1, introducing flue gas into the flue gas inlet, introducing absorbent into the lean liquid inlet, the flue gas and the absorbent contacting each other to generate a decarbonization reaction, thereby forming decarbonized flue gas and rich liquid, the decarbonized flue gas entering the temperature control layer, and the rich liquid being discharged from the rich liquid outlet; S2, introducing a temperature-control washing liquid into the temperature-control water inlet, the decarbonized flue gas enters the temperature-control layer, contacts with the temperature-control washing liquid, and then enters the primary amine recovery layer; the temperature-control washing liquid contacts with the decarbonized flue gas and then enters the absorption layer to achieve the recovery of the absorbent and the replenishment of water; S3, using method S3-1 or method S3-2; Method S3-1 is: a primary water washing liquid is introduced into the primary water inlet, the decarbonized flue gas enters the primary amine recovery layer, contacts with the primary washing liquid at the primary packing layer, and then enters the secondary amine recovery layer; the primary washing liquid contacts with the decarbonized flue gas to form a primary recovery liquid, and part of the primary recovery liquid is introduced into the temperature control layer as a temperature control washing liquid; Method S3-2 is: introducing a primary water wash liquid into the primary water inlet to wet the primary packing layer, then stopping introducing the primary water wash liquid, the decarbonized flue gas enters the primary amine recovery layer, contacts the wet primary packing layer, and then enters the secondary amine recovery layer; S4. A secondary water washing liquid is introduced into the secondary water inlet, and the decarbonized flue gas enters the secondary amine recovery layer, contacts with the secondary washing liquid at the secondary packing layer, and then is discharged through the tail gas outlet; the secondary washing liquid contacts with the decarbonized flue gas to form a secondary recovery liquid, and part of the secondary recovery liquid is introduced into the temperature control layer as a temperature control washing liquid.

8. The carbon capture method according to claim 7, characterized in that: When the absorbent escapes mainly in gaseous form, step S3 adopts method S3-1; when the absorbent escapes mainly in aerosol form, step S3 adopts method S3-2.

9. The carbon capture method according to claim 7, characterized in that: In method S3-1, in the primary amine recovery layer, the ratio of the flow rate of the primary water wash liquid to the flow rate of the decarbonized flue gas is 1:(400-3000); And / or, in step S4, in the secondary amine recovery layer, the ratio of the inlet flow rate of the secondary water washing liquid to the inlet flow rate of the decarbonized flue gas is 1:(400-3000).

10. The carbon capture method according to claim 7, characterized in that: The temperature of the flue gas is 30-50°C; and / or, the temperature of the decarbonized flue gas after passing through the absorption layer is 60-70° C.; and / or, the temperature of the decarbonized flue gas after passing through the temperature control layer is 50-60° C.; and / or, the temperature of the decarbonized flue gas after passing through the primary amine recovery layer is 40-50° C.; and / or, the temperature of the decarbonized flue gas after passing through the secondary amine recovery layer is 35-40° C.; And / or, the amine concentration of the decarbonized flue gas after passing through the secondary amine recovery layer is ≤10 ppm.

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