Regeneration tower top desorption steam heat recovery and steam-liquid separation device

Abstract

The utility model discloses a regeneration tower top desorption steam heat recovery and steam-liquid separation device in the technical field of chemical engineering, which comprises a regeneration tower, a lean amine liquid storage part and a desorption part are respectively arranged at the lower part and the upper part of the regeneration tower, and a reboiler is arranged between the lean amine liquid storage part and the desorption part; a first desorption steam outlet is formed in the top of the regeneration tower, the first desorption steam outlet is communicated with a first heat exchanger, the first heat exchanger is provided with an amine-rich liquid inlet pipe and an amine-rich liquid outlet pipe, the amine-rich liquid outlet pipe is communicated with the desorption part, and the first heat exchanger is used for realizing heat exchange between acid steam and amine-rich liquid; the first heat exchanger is further communicated with a gas-liquid separator, the gas-liquid separator is provided with a second desorption steam outlet and a condensate outlet pipe, the second desorption steam outlet is communicated with a condenser, the condenser is provided with an exhaust port and a condensate outlet, the condensate outlet is communicated with the gas-liquid separator, and the condensate outlet pipe is communicated with the desorption part; sO2 internal circulation is reduced, and steam energy consumption in the whole desorption process is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical engineering, in particular to a device for recovering the heat of desorbing steam at the top of a regenerator and separating gas from liquid. Background Art

[0002] An absorbent of aqueous monoamine or diamine absorbs SO 2 from flue gas 2 and generates an amine SO 2 salt, called rich amine liquid; under the action of elevated temperature and stripping steam flowing upward countercurrently to the downward flowing rich amine liquid through a regenerator (or called a desorber, or called a stripper), the amine SO 2 salt in the rich amine liquid decomposes into gaseous SO 2 and free amine containing a small amount of SO 2 , called lean amine liquid. The amine SO 2 salt in the rich amine liquid decomposes into gaseous SO 2 , containing water vapor, and leaves from the top of the regenerator. The water vapor containing SO 2 leaving from the top of the regenerator is called desorbing steam; the lean amine liquid is recycled to the absorption tower after heat recovery and cooling to remove SO 2 from flue gas.

[0003] Most of the steam provided by the reboiler at the bottom of the regenerator during the desorption process is taken away by the desorbing steam at the top of the tower. The energy consumption of the desorption process is extremely high, the thermodynamic efficiency is very low, and a large amount of energy is wasted. Moreover, in the prior art, after the steam is condensed, the SO 2 gas needs to be recovered, and the condensed liquid flows back to the regenerator. There is still a relatively large amount of SO 2 dissolved in the liquid. These dissolved SO 2 return to the regenerator together with the liquid after gas-liquid separation, resulting in a relatively large amount of SO 2 in the internal cycle. Content of the Utility Model

[0004] In order to overcome the deficiencies of the prior art, the technical problem to be solved by the utility model is: how to reduce the energy consumption of the desorption process and the content of SO 2 in the internal cycle of the regenerator.

[0005] The technical solution adopted by the utility model to solve its technical problem is:

[0006] Regenerative tower top desorbed steam heat recovery and vapor-liquid separation device, including a regenerative tower. A lean amine liquid storage section and a desorption section are respectively arranged at the lower and upper parts of the regenerative tower. A reboiler is arranged between the lean amine liquid storage section and the desorption section. A first desorbed steam outlet is arranged at the top of the regenerative tower. The first desorbed steam outlet is connected to a first heat exchanger. The first heat exchanger is provided with a rich amine liquid inlet pipe and a rich amine liquid outlet pipe. The rich amine liquid outlet pipe is connected to the desorption section. The first heat exchanger is used for heat exchange between acid gas and rich amine liquid. The first heat exchanger is also connected to a gas-liquid separator. The gas-liquid separator is respectively provided with a second desorbed steam outlet and a condensate outlet pipe. The second desorbed steam outlet is connected to a condenser. The condenser is provided with an exhaust port, and the condenser is provided with a condensate outlet. The condensate outlet is connected to the gas-liquid separator. The condensate outlet pipe is connected to the desorption section.

[0007] Furthermore, a lean amine liquid outlet pipe is connected to the lean amine liquid storage section. A lean amine liquid pump is arranged on the lean amine liquid outlet pipe. A second heat exchanger is connected to one side of the lean amine liquid storage section and the lean amine liquid outlet pipe. The second heat exchanger is also provided with a lean amine liquid outlet, a rich amine liquid inlet, and a rich amine liquid outlet. The second heat exchanger is used for heat exchange between lean amine liquid and rich amine liquid. The rich amine liquid outlet is connected to the rich amine liquid inlet pipe.

[0008] Furthermore, a connecting pipe is arranged between the reboiler and the regenerative tower.

[0009] Furthermore, the condenser is provided with a circulating cooling water pipe.

[0010] Furthermore, the first heat exchanger is provided with a gas phase outlet. The gas phase outlet is connected to the gas-liquid separator.

[0011] Furthermore, a spraying pipe is arranged at the upper part of the gas-liquid separator. The spraying pipe is connected to the condensate outlet.

[0012] Furthermore, a condensate pump is arranged on the condensate outlet pipe.

[0013] The beneficial effects of the present utility model are:

[0014] The rich amine liquid enters the desorption section in the regenerative tower through the rich amine liquid outlet pipe. Through steam desorption, gaseous SO 2 accompanies the steam and enters the first heat exchanger from the desorbed steam outlet. The acid gas and the rich amine liquid achieve heat exchange, increasing the temperature of the rich amine liquid and reducing the desorption heat required for the rich amine liquid in the desorption section, thereby reducing steam consumption. The acid gas that has completed heat exchange enters the gas-liquid separator and contacts the continuously circulating condensate in the gas-liquid separator, and the acid gas is further cooled, removing the water vapor in the acid gas to form relatively pure SO 2The gas is discharged from the exhaust pipe of the condenser. During this process, the acid vapor contacts and exchanges heat with the condensate, causing the temperature of the condensate to rise, reducing the solubility of SO in the condensate, and lowering the SO content in the condensate in the gas-liquid separator. At this time, the condensate in the gas-liquid separator is pumped into the desorption section through the condensate outlet pipe, which can reduce the amount of SO circulating in the desorption section. In this way, through the subsequent heat exchange and recovery process of the high-temperature acid vapor formed during the desorption process, the SO in the condensate pumped into the desorption section can be further reduced. In essence, it reduces the internal circulation of SO, which is equivalent to improving the desorption efficiency of the rich amine solution, synchronously reducing the energy consumption during the entire desorption process, and enhancing economic benefits. 2 in the condensate in the gas-liquid separator 2 content is reduced. At this time, the condensate in the gas-liquid separator is pumped into the desorption section through the condensate outlet pipe, which can reduce the amount of SO 2 circulating in the desorption section. In this way, through the subsequent heat exchange and recovery process of the high-temperature acid vapor formed during the desorption process, the SO in the condensate pumped into the desorption section can be further reduced. 2 In essence, it reduces the internal circulation of SO 2 which is equivalent to improving the desorption efficiency of the rich amine solution, synchronously reducing the energy consumption during the entire desorption process, and enhancing economic benefits. Description of the Drawings

[0015] Figure 1 is a schematic diagram of the connection structure of the present utility model;

[0016] In the figure, the labels are: 1 - regeneration tower, 2 - lean amine liquid storage section, 3 - desorption section, 4 - first desorption steam outlet, 5 - first heat exchanger, 6 - rich amine liquid inlet pipe, 7 - rich amine liquid outlet pipe, 8 - gas-liquid separator, 9 - second desorption steam outlet, 10 - condenser, 11 - exhaust port, 12 - condensate outlet, 13 - condensate outlet pipe, 14 - lean amine liquid outlet pipe, 15 - lean amine liquid pump, 16 - second heat exchanger, 17 - lean amine liquid outlet, 18 - rich amine liquid inlet, 19 - rich amine liquid outlet, 20 - reboiler, 21 - connecting pipe, 22 - circulating cooling water pipe, 23 - gas phase outlet, 24 - spraying pipe, 25 - condensate pump. Detailed Embodiments

[0017] The present utility model will be further described below with reference to the accompanying drawings.

[0018] According to Figure 1As shown in the figure, an apparatus for recovering the heat of the desorbed steam at the top of the regenerator and separating vapor and liquid is proposed in an embodiment of the present application, which includes a regenerator 1. A lean amine liquid storage section 2 and a desorption section 3 are respectively arranged at the lower and upper parts of the regenerator 1. A reboiler is arranged between the lean amine liquid storage section 2 and the desorption section 3. A first desorbed steam outlet 4 is arranged at the top of the regenerator 1. The first desorbed steam outlet 4 is communicated with a first heat exchanger 5. The first heat exchanger 5 is provided with a rich amine liquid inlet pipe 6 and a rich amine liquid outlet pipe 7. The rich amine liquid outlet pipe 7 is communicated with the desorption section 3. The first heat exchanger 5 is used for heat exchange between the acid gas and the rich amine liquid. The first heat exchanger 5 is also communicated with a gas-liquid separator 8. The gas-liquid separator 8 is respectively provided with a second desorbed steam outlet 9 and a condensate outlet pipe 13. The second desorbed steam outlet 9 is communicated with a condenser 10. The condenser 10 is provided with an exhaust port 11, and the condenser 10 is provided with a condensate outlet 12. The condensate outlet 12 is communicated with the gas-liquid separator 8. The condensate outlet pipe 13 is communicated with the desorption section 3.

[0019] In addition, the desorption section 3 of the regenerator 1 has two sections: the lower section is the rich amine liquid desorption section part, and the upper section is the condensate washing regenerated steam part. The condensate washing regenerated steam part is also called the reflux section, and the desulfurization agent in the steam after desorption is washed away by the re-reflux of the condensate.

[0020] First of all, it should be stated that the rich amine liquid enters the desorption section 3 in the regenerator 1 through the rich amine liquid outlet pipe. Through the steam desorption process, gaseous SO 2 accompanies the steam and enters the first heat exchanger 5 from the first desorbed steam outlet 4. The acid gas and the rich amine liquid realize heat exchange, increasing the temperature of the rich amine liquid and reducing the desorption heat required for the rich amine liquid in the desorption section 3, thereby reducing the steam consumption. The acid gas that has completed heat exchange enters the gas-liquid separator 8 and contacts the condensate from the condenser 10, and the acid gas is further cooled, so that the water vapor in the acid gas is removed. The SO 2 gas with reduced temperature enters the condenser 10. Moreover, in this process, the acid gas and the condensate contact and exchange heat, increasing the temperature of the condensate and reducing the solubility of SO 2 in the condensate, so that the content of SO 2 in the condensate in the gas-liquid separator 8 is reduced. At this time, the condensate in the gas-liquid separator 8 is pumped into the desorption section 3 through the condensate outlet pipe 13, which can reduce the amount of SO 2 circulating in the desorption section 3, thus reducing the high-temperature acid gas formed during the desorption process, reducing the energy loss in the entire desorption process, and improving the economic benefits.

[0021] A connecting pipe 21 is arranged between the reboiler 20 and the regenerator 1. Steam is input into the regenerator 1 through the external heat source of the reboiler 20 to supplement heat for the desorption process in the regenerator 1, ensuring the normal and efficient progress of the desorption process.

[0022] Moreover, in order to further utilize the heat generated during the desorption process, a lean amine liquid outlet pipe 14 is connected to the above-mentioned lean amine liquid storage section 2. A lean amine liquid pump 15 is provided on the lean amine liquid outlet pipe 14. A second heat exchanger 16 is connected to the lean amine liquid outlet pipe 14. The second heat exchanger 16 is also provided with a lean amine liquid outlet 17, a rich amine liquid inlet 18, and a rich amine liquid outlet 19. The second heat exchanger 16 is used for heat exchange between the lean amine liquid and the rich amine liquid; the rich amine liquid outlet 19 is connected to the rich amine liquid inlet pipe 6; that is to say, the lean amine liquid formed after desorption is collected in the lean amine liquid storage section 2, and the lean amine liquid has a certain amount of heat after desorption. By exchanging heat with the rich amine liquid produced by the absorption tower in the second heat exchanger 16, the temperature of the rich amine liquid is increased to a certain extent, reducing the heat required for the rich amine liquid in the subsequent desorption process and reducing energy consumption. Moreover, the condenser 10 is provided with a circulating cooling water pipe 22, which can continuously provide condensate for the gas-liquid separator 8. The condensate in this application is condensed water containing a small amount of SO 2 ; a condensate pump 25 is provided on the condensate outlet pipe 13 to ensure that the condensate that has completed heat and mass transfer in the gas-liquid separator 8 can stably enter the desorption section 3 of the regeneration tower 1,

[0023] Specifically, the lower the temperature of the acid gas containing SO 2 after condensation, the more SO 2 dissolved in the condensate, and the more SO 2 returned to the regeneration tower 1 along with the condensate; the top of the regeneration tower 1 is controlled at a certain temperature and pressure. The more SO 2 , the more water vapor is carried out with SO 2 , and the more steam is consumed for desorption; in addition, the lower the temperature of the condensate returned to the regeneration tower 1, the more steam is consumed for desorption.

[0024] To achieve the purpose of energy conservation, the desorption steam at the top of the regeneration tower 1 and the acid gas containing SO 2 still reach about 100 °C after heat recovery. The steam is mainly SO 2 with a volume content of 2% - 15%, and the rest is basically water vapor, and the water vapor has a relatively large amount of low-temperature heat enthalpy. The steam passes through the gas-liquid separator 8, which is to directly contact the water vapor containing SO 2 with the relatively low-temperature condensate for mass transfer and heat transfer. The temperature of the condensate from the condenser 10 is 25 - 60 °C. After the condensate exchanges heat with the water vapor containing SO 2 , its temperature rises, and the ability of the condensate to dissolve SO 2 is greatly reduced. Almost all of the SO 2 in the condensate is transferred to the gas phase, significantly reducing the SO 2 returning to the regeneration tower 11 with the condensate.Content. The temperature of the condensate at the lower part of the gas-liquid separator 8 rises to 90 - 105 °C, and then returns to the regeneration tower 1 through the condensate pump 25. The temperature of the condensate rises from 25 - 60 °C to 90 - 105 °C, achieving the purpose of energy conservation.

[0025] In the gas-liquid separator 8, there may be an insufficient contact between the acid vapor and the condensate. To improve the above situation, the first heat exchanger 5 is provided with a gas phase outlet 23, and the gas phase outlet 23 communicates with the lower part of the gas-liquid separator 8. In this way, it can be ensured that the acid vapor needs to completely pass through the condensate to reach the second desorbed steam outlet 9, ensuring that the acid vapor is fully contacted under the sufficient washing action of the condensate and guaranteeing the high-efficiency stability of the mass transfer and heat transfer processes. Further, a spraying pipe 24 is provided at the upper part of the gas-liquid separator 8, and the spraying pipe 24 communicates with the condensate liquid outlet 12. That is to say, the condensate in the condenser 10 further fully contacts the acid vapor entering the gas-liquid separator 8 by spraying at the upper part of the gas-liquid separator 8, which can further improve the degree of sufficient contact between the acid vapor and the condensate.

[0026] Moreover, the condensate entering the desorption section 3 mainly maintains the water balance and recovers SO in the water 2 , and also removes the desulfurizer entrained in the steam, further improving the efficiency of the desorption process.

[0027] In summary, the present utility model provides a device for recovering the heat of desorbed steam at the top of a regenerator and for vapor-liquid separation, which comprises a regenerator 1. A lean amine liquid storage section 2 and a desorption section 3 are respectively arranged at the lower part and the upper part of the regenerator 1. A reboiler is arranged between the lean amine liquid storage section 2 and the desorption section 3. A first desorbed steam outlet 4 is arranged at the top of the regenerator 1. The first desorbed steam outlet 4 is connected to a first heat exchanger 5. The first heat exchanger 5 is provided with a rich amine liquid inlet pipe 6 and a rich amine liquid outlet pipe 7. The rich amine liquid outlet pipe 7 is connected to the desorption section 3. The first heat exchanger 5 is used for heat exchange between acid gas and rich amine liquid. The first heat exchanger 5 is further connected to a gas-liquid separator 8. The gas-liquid separator 8 is respectively provided with a second desorbed steam outlet 9 and a condensate outlet pipe 13. The second desorbed steam outlet 9 is connected to a condenser 10. The condenser 10 is provided with an exhaust port 11, and the condenser 10 is provided with a condensate outlet 12. The condensate outlet 12 is connected to the gas-liquid separator 8. The condensate outlet pipe 13 is connected to the desorption section 3. The desorbed steam leaving the regenerator 1 first undergoes heat exchange with rich amine liquid in the first heat exchanger 5, and the temperature is reduced to 90-105°C. Then, the desorbed steam directly contacts the condensate flowing from the condenser 10 for mass transfer and heat transfer, increasing the temperature of the condensate. The low-temperature heat enthalpy of the desorbed steam can be more fully utilized, thus making full use of the heat existing in the production process. The lean amine liquid after desorption and the rich amine liquid achieve heat transfer in the second heat exchanger 16, increasing the temperature of the rich amine liquid to be desorbed, thereby reducing the heat required for the desorption process, further recovering heat, reducing heat consumption, and enhancing the economic benefits of the entire device.

Claims

1. Regeneration tower top desorption steam heat recovery and vapor-liquid separation device, characterized in that: The invention comprises a regeneration tower (1), wherein a lean amine liquid storage section (2) and a desorption section (3) are respectively arranged at the lower part and the upper part of the regeneration tower (1), and a reboiler (20) is arranged between the lean amine liquid storage section (2) and the desorption section (3); a first desorption steam outlet (4) is arranged at the top of the regeneration tower (1), and the first desorption steam outlet (4) is connected to a first heat exchanger (5), and the first heat exchanger (5) is provided with a rich amine liquid inlet pipe (6) and a rich amine liquid outlet pipe (7), and the rich amine liquid outlet pipe (7) is connected to the desorption section (3 ... inlet pipe (7) is connected to the desorption section (3), and the first heat exchanger (5) is provided with a rich amine liquid inlet pipe (6) and a rich amine liquid outlet pipe (7), and the rich amine liquid inlet pipe (7) is connected to the desorption section (3), and the ) is used for heat exchange between acid vapor and rich amine liquid; the first heat exchanger (5) is also connected to a gas-liquid separator (8), the gas-liquid separator (8) is respectively provided with a second desorption steam outlet (9) and a condensate outlet pipe (13), the second desorption steam outlet (9) is connected to a condenser (10), the condenser (10) is provided with an exhaust port (11), and the condenser (10) is provided with a condensate outlet (12), and the condensate outlet (12) is connected to the gas-liquid separator (8), and the condensate outlet pipe (13) is connected to the desorption section (3).

2. The regeneration tower top desorption steam heat recovery and vapor-liquid separation device according to claim 1, characterized in that: The lean amine liquid storage section (2) is connected to a lean amine liquid outlet pipe (14), and the lean amine liquid outlet pipe (14) is provided with a lean amine liquid pump (15). The side of the lean amine liquid outlet pipe (14) away from the lean amine liquid storage section (2) is connected to a second heat exchanger (16), and the second heat exchanger (16) is also provided with a lean amine liquid outlet (17), a rich amine liquid inlet (18) and a rich amine liquid outlet (19). The second heat exchanger (16) is used for heat exchange between lean amine liquid and rich amine liquid; the rich amine liquid outlet (19) is connected to the rich amine liquid inlet pipe (6).

3. The regeneration tower top desorption steam heat recovery and vapor-liquid separation device according to claim 1, characterized in that: A connecting pipe (21) is provided between the reboiler (20) and the regeneration tower (1).

4. The regeneration tower top desorption steam heat recovery and vapor-liquid separation device according to claim 1, characterized in that: The condenser (10) is provided with a circulating cooling water pipeline (22).

5. The regeneration tower top desorption steam heat recovery and vapor-liquid separation device according to claim 1, characterized in that: The first heat exchanger (5) is provided with a gas phase outlet (23), and the gas phase outlet (23) is connected to the lower part of the gas-liquid separator (8).

6. The regeneration tower top desorption steam heat recovery and vapor-liquid separation device according to claim 1, characterized in that: A spray pipe (24) is provided on the upper part of the gas-liquid separator (8), and the spray pipe (24) is connected to the condensate outlet (12).

7. The regeneration tower top desorption steam heat recovery and vapor-liquid separation device according to claim 1, characterized in that: The condensate outlet pipe (13) is provided with a condensate pump (25).

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