Energy-saving and environment-friendly organic amine solvent regeneration system and regeneration method

Abstract

The invention belongs to the technical field of carbon dioxide capture, and particularly relates to an energy-saving and environment-friendly organic amine solvent regeneration system and regeneration method. The energy-saving and environment-friendly organic amine solvent regeneration system comprises a regeneration tower, a boiler, a condensate water tank and a steam temperature and pressure reduction device which are sequentially and circularly connected, and also comprises a steam trap and a condensate water pump which can be further arranged. According to the invention, the heat of the steam condensate water as the desuperheating water part is recycled, so that the amount of externally supplied steam is reduced, and the regeneration energy consumption of the organic amine solution is reduced; the discharge amount of steam condensate water is reduced, the load on a condensate water system or a unit drainage tank of a thermal power plant is reduced, and visual pollution caused by the condensate water is reduced; in addition, the steam temperature and pressure reduction device does not need to externally supply deionized water, so that the consumption of the deionized water can be reduced; in addition, the technical scheme provided by the invention can be realized only by modifying an existing organic amine solution regeneration system and a steam supply system, and the generalization performance is better.

Description

Technical Field

[0001] The invention belongs to the technical field of carbon dioxide capture, and in particular relates to an energy-saving and environmentally friendly organic amine solvent regeneration system and regeneration method. Background Art

[0002] Organic amine chemical absorption carbon capture technology is widely used in flue gas carbon dioxide capture. In the organic amine carbon capture process, energy consumption mainly occurs in the regeneration process of organic amine solution. The commonly used regeneration temperature of organic amine solution is 105-120℃, and the required steam is generally low-quality (about 0.4MPa, 144℃) saturated steam, while the steam provided by thermal power plants is generally 0.6-1.0MPa, and the temperature is 180-250℃ superheated steam. In order to prevent the occurrence of overheating during the regeneration process of organic amine solution, when using steam to heat and regenerate the organic amine solution, the steam needs to be cooled and decompressed. At present, deionized water is commonly used to cool and decompress high-temperature and high-pressure steam.

[0003] After the steam heats and regenerates the organic amine solution, a large amount of high-temperature condensed water (100℃~110℃) is generated. In the common flue gas carbon capture devices in coal-fired power plants, the water discharged from the regenerated steam of the organic amine solution is mostly directly discharged into the unit drainage trough or pit for working fluid recovery. When the carbon capture scale reaches more than 100,000 tons / year, the steam condensed water discharged per hour is about 15 tons, or even more. In order to reduce water vapor loss and visual pollution, a large amount of cooling water is required to be added or the condensed water is cooled before being discharged. Not only is the heat of the high-temperature condensed water completely lost, but the consumption of cooling water is also increased. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the present invention provides an energy-saving and environmentally friendly organic amine solvent regeneration system, comprising a regeneration tower, a boiler, a condensed water tank and a steam temperature and pressure reduction device which are cyclically connected in sequence; wherein:

[0005] The regeneration tower is provided with a first rich liquid outlet and a first lean liquid inlet at the middle and lower part, and the boiler is provided with a first rich liquid inlet and a first lean liquid outlet; the first rich liquid outlet is connected to the first rich liquid inlet, and the first lean liquid outlet is connected to the first lean liquid inlet;

[0006] The boiler is provided with a first steam inlet and a first steam condensate outlet, the steam temperature reduction and pressure reduction device is provided with a second steam inlet, a steam outlet and a temperature reduction water inlet, the middle of the condensate tank is provided with a steam condensate inlet, and the bottom is provided with a second steam condensate outlet;

[0007] The first steam inlet is connected to the steam outlet, the first steam condensate outlet is connected to the steam condensate inlet, the second steam condensate outlet is connected to the cooling water inlet, and the second steam inlet is connected to an external steam supply pipeline.

[0008] Preferably, an atomizing device is provided at the cooling water inlet, and the atomizing device is used to atomize the cooling water into tiny droplets in the steam cooling and pressure reducing device to improve the cooling effect.

[0009] Preferably, the energy-saving and environmentally friendly organic amine solvent regeneration system further comprises a steam trap, and two ends of the steam trap are respectively connected to the steam condensate first outlet and the steam condensate inlet.

[0010] Preferably, the energy-saving and environmentally friendly organic amine solvent regeneration system further includes a condensate pump; wherein:

[0011] The inlet and outlet of the condensate pump are respectively connected to the second outlet of the steam condensate and the desuperheating water inlet;

[0012] The condensate pump outlet is also connected to a drainage ditch or a pit of a coal-fired power plant unit.

[0013] Preferably, the condensate water pump is provided in two units, including a first condensate water pump and a second condensate water pump; wherein:

[0014] The first condensate pump and the second condensate pump are arranged in parallel, so that one is used and the other is reserved, which can ensure the safe and stable operation of the system.

[0015] Preferably, a second rich liquid inlet is provided at the top of the regeneration tower, a second lean liquid outlet is provided at the bottom, and a regeneration gas outlet is provided at the top. The second rich liquid inlet is connected to the rich liquid formed after the organic amine solution absorbs carbon dioxide.

[0016] Based on the same technical concept, the present invention further provides an energy-saving and environmentally friendly method for regenerating an organic amine solvent, which is applied to any of the above-mentioned organic amine solvent regeneration systems, and comprises the following steps:

[0017] (1) introducing the rich liquid formed after the organic amine solution absorbs carbon dioxide into the regeneration tower for analysis, and then introducing it into the boiler after the analysis is completed;

[0018] (2) then introducing steam that has been cooled and decompressed by the steam temperature and pressure reduction device into the boiler to heat the rich liquid, and the rich liquid is returned to the regeneration tower after being heated;

[0019] (3) After the rich liquid is desorbed, a lean liquid and carbon dioxide gas are obtained. The steam provides heat to the rich liquid to form steam condensate. The steam condensate passes through the condensate tank and is used as cooling water for the cooling and pressure reducing device. The temperature of the external steam is reduced to a set value and then used as a heat source to heat the rich liquid in the boiler, thereby completing the entire regeneration process.

[0020] Preferably, in step (1), the rich liquid formed after the organic amine solution absorbs carbon dioxide is introduced into the regeneration tower for analysis, and after completion, is introduced into the boiler through the first rich liquid outlet and the first rich liquid inlet;

[0021] And / or, in step (2), the steam cooled and decompressed after passing through the steam temperature-reducing and pressure-reducing device is then introduced into the boiler, and the steam enters the boiler through the steam outlet and the first steam inlet in sequence to heat the rich liquid, and the rich liquid is heated and then returns to the regeneration tower through the first lean liquid outlet and the first lean liquid inlet in sequence;

[0022] And / or, in step (3), after the rich liquid is desorbed, a lean liquid and carbon dioxide gas are obtained, which are discharged from the lean liquid second outlet and the regenerated gas outlet respectively; the steam provides heat to the rich liquid to form steam condensate, which flows through the steam condensate first outlet, the steam condensate inlet and the steam condensate second outlet in sequence; the steam condensate is used as cooling water of the cooling and pressure reducing device after passing through the condensation water tank, and enters the steam cooling and pressure reducing device through the cooling water inlet, and the temperature of the external steam entering through the steam second inlet is reduced to a set value and then used as a heat source to heat the rich liquid in the boiler, thereby completing the entire regeneration process.

[0023] Implementing the technical solution of the present invention will have the following beneficial effects:

[0024] The present invention provides an energy-saving and environmentally friendly organic amine solvent regeneration system and regeneration method, wherein the regeneration system comprises a regeneration tower, a boiler, a steam trap, a condensate tank, a condensate pump and a steam temperature and pressure reduction device which are connected in a circular manner in sequence.

[0025] The first rich liquid outlet and the first lean liquid inlet are arranged in the middle and lower part of the regeneration tower, the first rich liquid inlet and the first lean liquid outlet are arranged in the boiler, the first rich liquid outlet is connected to the first rich liquid inlet, and the first lean liquid outlet is connected to the first lean liquid inlet. The boiler is also provided with a first steam inlet and a first steam condensate outlet, the steam temperature reduction and pressure reduction device is provided with a second steam inlet, a steam outlet and a cooling water inlet, a steam condensate inlet is arranged in the middle part of the condensate tank, a second steam condensate outlet is arranged at the bottom, the first steam inlet is connected to the steam outlet, the first steam condensate outlet is connected to the steam condensate inlet, the second steam condensate outlet is connected to the cooling water inlet, and the steam condensate part is used as cooling water for the cooling and pressure reduction device, and after the temperature of the externally supplied steam is reduced to the set value, it is used as a heat source to heat the rich liquid in the boiler. Therefore, the heat of the steam condensate used as the cooling water is recycled, reducing the amount of external steam supply, thereby reducing the regeneration energy consumption of the organic amine solution; reducing the amount of steam condensate discharged, reducing the load on the condensate system or unit drainage tank of the thermal power plant, and reducing the visual pollution caused by the condensate; and, the steam cooling and pressure reduction device does not require external deionized water supply, which can reduce the consumption of deionized water. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a schematic diagram of the energy-saving and environment-friendly organic amine solvent regeneration system of the present invention.

[0028] Figure 2 This is a first partial schematic diagram of the energy-saving and environment-friendly organic amine solvent regeneration system of the present invention.

[0029] Figure 3 This is a second partial schematic diagram of the energy-saving and environment-friendly organic amine solvent regeneration system of the present invention.

[0030] The accompanying drawings in the figure are marked as follows:

[0031] 1-regeneration tower; 11-first rich liquid outlet; 12-first lean liquid inlet; 13-second rich liquid inlet; 14-second lean liquid outlet; 15-regeneration gas outlet;

[0032] 2- boiler; 21- first rich liquid inlet; 22- first lean liquid outlet; 23- first steam inlet; 24- first steam condensate outlet;

[0033] 3- condensed water tank; 31- steam condensate inlet; 32- steam condensate second outlet;

[0034] 4-steam temperature reduction and pressure reduction device; 41-steam second inlet; 42-steam outlet; 43-temperature reduction water inlet; 44-external steam supply pipeline;

[0035] 5-Steam trap;

[0036] 6- condensate pump; 61- first condensate pump; 62- second condensate pump;

[0037] 7- Drainage troughs or pits of coal-fired power plant units. DETAILED DESCRIPTION

[0038] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0039] Example 1

[0040] refer to Figure 1 to Figure 3 This embodiment provides an energy-saving and environmentally friendly organic amine solvent regeneration system, comprising a regeneration tower 1, a boiler 2, a condensed water tank 3 and a steam temperature and pressure reduction device 4 which are cyclically connected in sequence; wherein:

[0041] The regeneration tower 1 is provided with a first rich liquid outlet 11 and a first lean liquid inlet 12 at the middle and lower part, and the boiler 2 is provided with a first rich liquid inlet 21 and a first lean liquid outlet 22; the first rich liquid outlet 11 is connected to the first rich liquid inlet 21, and the first lean liquid outlet 22 is connected to the first lean liquid inlet 12;

[0042] The boiler 2 is provided with a first steam inlet 23 and a first steam condensate outlet 24, the steam temperature reduction and pressure reduction device 4 is provided with a second steam inlet 41, a steam outlet 42 and a temperature reduction water inlet 43, the condensate tank 3 is provided with a steam condensate inlet 31 in the middle, and a steam condensate second outlet 32 ​​at the bottom;

[0043] The first steam inlet 23 is connected to the steam outlet 42 , the first steam condensate outlet 24 is connected to the steam condensate inlet 31 , the second steam condensate outlet 32 ​​is connected to the cooling water inlet 43 , and the second steam inlet 41 is connected to an external steam supply pipeline 44 .

[0044] As an optional embodiment, the cooling water inlet 43 is provided with an atomizing device, and the atomizing device is used to atomize the cooling water into tiny droplets in the steam cooling and pressure reducing device 4 to improve the cooling effect.

[0045] As an optional embodiment, the energy-saving and environmentally friendly organic amine solvent regeneration system further includes a steam trap 5 , and two ends of the steam trap 5 are respectively connected to the steam condensate first outlet 24 and the steam condensate inlet 31 .

[0046] As an optional implementation, the energy-saving and environmentally friendly organic amine solvent regeneration system further includes a condensate pump 6; wherein:

[0047] The inlet and outlet of the condensate pump 6 are respectively connected to the steam condensate second outlet 32 ​​and the desuperheating water inlet 43;

[0048] The condensate pump outlet is also connected to a drainage trough or a pit 7 of a coal-fired power plant unit.

[0049] As an optional implementation, the condensate water pump 6 is provided with two, including a first condensate water pump 61 and a second condensate water pump 62; wherein:

[0050] The first condensate pump 61 and the second condensate pump 62 are arranged in parallel. With such an arrangement, one is used and the other is reserved, which can ensure safe and stable operation of the system.

[0051] As an optional embodiment, the regeneration tower 1 is provided with a rich liquid second inlet 13 at the top, a lean liquid second outlet 14 at the bottom, and a regeneration gas outlet 15 at the top. The rich liquid second inlet 13 is connected to the rich liquid formed after the organic amine solution absorbs carbon dioxide.

[0052] Furthermore, taking an organic amine chemical absorption method for capturing coal-fired flue gas with an annual output of 100,000 tons as an example, embodiments 2 to 7 and comparative examples 2 to 7 are set, specifically: the annual operation time of the device is 8000 hours, the carbon dioxide production per small test is 12.5 tons, and the long-term average regeneration energy consumption of the organic amine solution is 2.8 GJ / tCO 2 , external heat supply of 35GJ / h is required.

[0053] The specific regeneration process is as follows: the rich liquid after the organic amine solution absorbs carbon dioxide enters the regeneration tower for decomposition, and then enters the boiler, and the steam (for heating the rich liquid) that has been cooled and depressurized by the steam desuperheating and decompression device is introduced into the boiler, and the rich liquid returns to the regeneration tower after being heated. After the rich liquid is desorbed, the lean liquid and carbon dioxide gas are obtained, and the steam provides heat to the rich liquid to form steam condensate. The steam condensate is used as cooling water for the desuperheating and decompression device, and the temperature of the external steam is reduced to the set value, and then used as a heat source to heat the rich liquid in the boiler.

[0054] Example 2

[0055] The thermal power plant provides steam with a pressure of 1.0MPa and a temperature of 280℃. Steam condensate (0.3MPa, 108℃) is used as steam desuperheating and decompression water. A part of the steam condensate is connected to the desuperheating and decompression device to adjust the steam at the inlet of the organic amine solution regeneration boiler to 0.4MPa and a temperature of 144℃.

[0056] Comparative Example 2

[0057] Compared with Example 2, the difference is that deionized water (0.1 MPa, 25° C.) is used to reduce the temperature and pressure of the steam provided by the thermal power plant, and all the condensed water is discharged into the drainage tank through a condensate pump.

[0058] Example 3

[0059] The thermal power plant provides steam with a pressure of 0.8MPa and a temperature of 280℃. Steam condensate (0.3MPa, 108℃) is used as steam desuperheating and decompression water. A part of the steam condensate is connected to the desuperheating and decompression device to adjust the steam at the inlet of the organic amine solution regeneration boiler to 0.4MPa and a temperature of 144℃.

[0060] Comparative Example 3

[0061] Compared with Example 3, the difference is that deionized water (0.1 MPa, 25° C.) is used to reduce the temperature and pressure of the steam provided by the thermal power plant, and all the condensed water is discharged into the drain tank through a condensate pump.

[0062] Example 4

[0063] The thermal power plant provides steam with a pressure of 0.8MPa and a temperature of 240℃. Steam condensate (0.3MPa, 108℃) is used as steam desuperheating and decompression water. A part of the steam condensate is connected to the desuperheating and decompression device to adjust the steam at the inlet of the organic amine solution regeneration boiler to 0.4MPa and a temperature of 144℃.

[0064] Comparative Example 4

[0065] Compared with Example 4, the difference is that deionized water (0.1 MPa, 25° C.) is used to reduce the temperature and pressure of the steam provided by the thermal power plant, and all the condensed water is discharged into the drain tank through a condensate pump.

[0066] Example 5

[0067] The thermal power plant provides steam with a pressure of 1.0MPa and a temperature of 280℃. Steam condensate (0.25MPa, 105℃) is used as steam desuperheating and decompression water. A part of the steam condensate is connected to the desuperheating and decompression device to adjust the steam at the inlet of the organic amine solution regeneration boiler to 0.25MPa and a temperature of 135℃.

[0068] Comparative Example 5

[0069] Compared with Example 5, the difference is that deionized water (0.1 MPa, 25° C.) is used to reduce the temperature and pressure of the steam provided by the thermal power plant, and all the condensed water is discharged into the drain tank through a condensate pump.

[0070] Example 6

[0071] The thermal power plant provides steam with a pressure of 0.8MPa and a temperature of 280℃. Steam condensate (0.25MPa, 105℃) is used as steam desuperheating and decompression water. A part of the steam condensate is connected to the desuperheating and decompression device to adjust the steam at the inlet of the organic amine solution regeneration boiler to 0.25MPa and a temperature of 135℃.

[0072] Comparative Example 6

[0073] Compared with Example 6, the difference is that deionized water (0.1 MPa, 25°C) is used to reduce the temperature and pressure of the steam provided by the thermal power plant, and all the condensed water is discharged into the drain tank through the condensate pump.

[0074] Example 7

[0075] The thermal power plant provides steam with a pressure of 0.8MPa and a temperature of 240℃. Steam condensate (0.25MPa, 105℃) is used as steam desuperheating and decompression water. A part of the steam condensate is connected to the desuperheating and decompression device to adjust the steam at the inlet of the organic amine solution regeneration boiler to 0.25MPa and a temperature of 135℃.

[0076] Comparative Example 7

[0077] Compared with Example 7, the difference is that deionized water (0.1 MPa, 25°C) is used to reduce the temperature and pressure of the steam provided by the thermal power plant, and all the condensed water is discharged into the drain tank through the condensate pump.

[0078] The results of Examples 2 to 7 and Comparative Examples 2 to 7 are shown in Table 1.

[0079] Table 1

[0080]

[0081]

[0082] It can be seen from Examples 2 to 7 and Comparative Examples 2 to 7 that, for a 100,000 ton / year organic amine carbon capture device, the method of the present invention can save about 1 t / h of deionized water, reduce external steam supply by 0.12 to 0.22 t / h, and reduce external steam condensate by 10%. As the scale of the carbon capture device expands, the amount of deionized water and steam saved will also increase.

[0083] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An energy-saving and environmentally friendly organic amine solvent regeneration system, characterized in that: It includes a regeneration tower, a boiler, a condensate tank and a steam temperature and pressure reduction device which are connected in a circular manner in sequence; wherein: The regeneration tower is provided with a first rich liquid outlet and a first lean liquid inlet at the middle and lower part, and the boiler is provided with a first rich liquid inlet and a first lean liquid outlet; the first rich liquid outlet is connected to the first rich liquid inlet, and the first lean liquid outlet is connected to the first lean liquid inlet; The boiler is provided with a first steam inlet and a first steam condensate outlet; the steam temperature and pressure reduction device is provided with a second steam inlet, a steam outlet and a temperature reduction water inlet; the condensate tank is provided with a steam condensate inlet in the middle and a steam condensate second outlet at the bottom; The first steam inlet is connected to the steam outlet, the first steam condensate outlet is connected to the steam condensate inlet, the second steam condensate outlet is connected to the cooling water inlet, and the second steam inlet is connected to an external steam supply pipeline.

2. The energy-saving and environmentally friendly organic amine solvent regeneration system according to claim 1 is characterized in that: The cooling water inlet is provided with an atomizing device, and the atomizing device is used to atomize the cooling water into tiny droplets in the steam cooling and pressure reducing device to improve the cooling effect.

3. The energy-saving and environmentally friendly organic amine solvent regeneration system according to claim 1 is characterized in that: It also includes a steam trap, two ends of which are respectively connected to the first steam condensate outlet and the steam condensate inlet.

4. The energy-saving and environmentally friendly organic amine solvent regeneration system according to claim 1 is characterized in that: Also included is a condensate pump; wherein: The inlet and outlet of the condensate pump are respectively connected to the second outlet of the steam condensate and the desuperheating water inlet; The condensate pump outlet is also connected to a drainage ditch or a pit of a coal-fired power plant unit.

5. The energy-saving and environmentally friendly organic amine solvent regeneration system according to claim 4 is characterized in that: The condensate water pump is provided with two, including a first condensate water pump and a second condensate water pump; wherein: The first condensate water pump and the second condensate water pump are arranged in parallel.

6. The energy-saving and environmentally friendly organic amine solvent regeneration system according to claim 1, characterized in that: The regeneration tower is provided with a second rich liquid inlet at the top, a second lean liquid outlet at the bottom, and a regeneration gas outlet at the top. The second rich liquid inlet is connected to the rich liquid formed after the organic amine solution absorbs carbon dioxide.

7. An energy-saving and environmentally friendly method for regenerating an organic amine solvent, characterized in that: The regeneration method adopts the regeneration system according to any one of claims 1 to 6.

8. The energy-saving and environmentally friendly method for regenerating an organic amine solvent according to claim 7, characterized in that: The organic amine solvent regeneration method comprises the following steps: (1) introducing the rich liquid formed after the organic amine solution absorbs carbon dioxide into the regeneration tower for analysis, and then introducing it into the boiler after the analysis is completed; (2) then introducing steam that has been cooled and decompressed by the steam temperature and pressure reduction device into the boiler to heat the rich liquid, and the rich liquid is returned to the regeneration tower after being heated; (3) After the rich liquid is desorbed, a lean liquid and carbon dioxide gas are obtained. The steam provides heat to the rich liquid to form steam condensate. The steam condensate passes through the condensate tank and is used as cooling water for the cooling and pressure reducing device. The temperature of the external steam is reduced to a set value and then used as a heat source to heat the rich liquid in the boiler, thereby completing the entire regeneration process.

9. The energy-saving and environmentally friendly method for regenerating an organic amine solvent according to claim 8, characterized in that: In step (1), the rich liquid formed after the organic amine solution absorbs carbon dioxide is introduced into the regeneration tower for analysis, and after completion, is introduced into the boiler through the first rich liquid outlet and the first rich liquid inlet; And / or, in step (2), the steam cooled and decompressed after passing through the steam temperature and pressure reduction device is then introduced into the boiler, and the steam enters the boiler through the steam outlet and the first steam inlet in sequence to heat the rich liquid, and the rich liquid is heated and returns to the regeneration tower through the first lean liquid outlet and the first lean liquid inlet in sequence; And / or, in step (3), after the rich liquid is desorbed, a lean liquid and carbon dioxide gas are obtained, which are discharged from the lean liquid second outlet and the regenerated gas outlet respectively; the steam provides heat to the rich liquid to form steam condensate, which flows through the steam condensate first outlet, the steam condensate inlet and the steam condensate second outlet in sequence; the steam condensate is used as cooling water of the cooling and pressure reducing device after passing through the condensation water tank, and enters the steam cooling and pressure reducing device through the cooling water inlet, and the temperature of the external steam entering through the steam second inlet is reduced to a set value and then used as a heat source to heat the rich liquid in the boiler, thereby completing the entire regeneration process.

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