Converted gas and desorbed gas decarburization regeneration device

Abstract

The utility model discloses a decarburization regeneration device for converted gas and desorbed gas, which is characterized by comprising an absorption tower, a purified gas exhaust pipe, a liquid discharge pipe, a liquid inlet pipe, a first gas inlet pipe and a second gas inlet pipe, and the purified gas exhaust pipe, the liquid discharge pipe, the liquid inlet pipe, the first gas inlet pipe and the second gas inlet pipe are arranged on the absorption tower. The first gas inlet pipe is arranged at the lower part of the lower-layer filler, the second gas inlet pipe is arranged at the lower part of the upper-layer filler, a circulating mechanism for supplying an NCMA solution is arranged between the liquid discharge pipe and the liquid inlet pipe, converted gas enters the absorption tower through the first gas inlet pipe, desorbed gas enters the absorption tower through the second gas inlet pipe, and CO2 in gas in the absorption tower is sucked out through the NCMA solution. The situation that the decarburization effect is not ideal due to the fact that regeneration gas is recycled in the decarburization process of the NCMA solution is relieved, and CO2 in converted gas and the regeneration gas is absorbed by changing the flow of the regeneration gas entering different filler layers of the absorption tower, so that it is guaranteed that the content of CO2 in decarburization gas is smaller than a design value.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of the removal of CO2-containing gas in modern industry, and particularly relates to a conversion gas and resolved gas decarburization regeneration device. BACKGROUND

[0002] The conversion gas from the natural gas non-catalytic conversion process after cooling, and the resolved gas sent by the subsequent process, the conversion gas contains H2 component about 62%, CO component about 31%, CH component less than or equal to 1%, N2 component less than or equal to 2.06%, CO2 component less than or equal to 6%, the resolved gas contains H2 component less than or equal to 40%, CO component less than or equal to 70%, CH component less than or equal to 0.1%, N2 component less than or equal to 15%, CO2 component less than or equal to 1PPM. At present, when the conversion gas from the natural gas non-catalytic conversion process and the resolved gas sent by the subsequent process are decarburized, the current process is relatively complex, and most of the decarburization absorption towers can perfectly remove the CO2 component, but are affected by different processes and operating equipment, have different absorption efficiencies for different component synthesis gas, and lead to difficult and clear CO2 absorption, especially the carbon dioxide content in the conversion gas is obviously greater than the concentration of the resolved gas, and the total amount of processing in the unit volume of the decarburization absorption tower is constant, when the total amount of the conversion gas input is too large, it is difficult to completely absorb CO2, and therefore, the purified gas contains CO2. Therefore, a device for decarburizing the conversion gas and the resolved gas is required. SUMMARY

[0003] In order to solve the technical problems existing in the prior art, the purpose of the present application is to provide a conversion gas and resolved gas decarburization regeneration device, which alleviates the situation that the NCMA solution in the decarburization process recovers regenerated gas, leading to unsatisfactory decarburization effect, and realizes CO2 absorption in the conversion gas and the resolved gas by changing the flow of the regenerated gas entering different filler layers of the absorption tower, so as to ensure that the CO2 content in the decarburized gas is less than the design value.

[0004] To solve the above-mentioned technical problems, the present application adopts the following technical solutions:

[0005] A conversion gas and resolved gas decarburization regeneration device, comprising an absorption tower, a purified gas exhaust pipe, a liquid discharge pipe, a liquid inlet pipe, a first gas inlet pipe and a second gas inlet pipe arranged on the absorption tower, the absorption tower is a packed absorption tower, the absorption tower is provided with upper layer filler and lower layer filler, the first gas inlet pipe is arranged at the lower part of the lower layer filler, the second gas inlet pipe is arranged at the lower part of the upper layer filler, a circulating mechanism for supplying NCMA solution is arranged between the liquid discharge pipe and the liquid inlet pipe, the conversion gas enters the absorption tower through the first gas inlet pipe, the resolved gas enters the absorption tower through the second gas inlet pipe, and CO2 in the gas in the absorption tower is absorbed by the NCMA solution.

[0006] Preferably, a cross-line pipeline is arranged between the first gas inlet pipe and the second gas inlet pipe, and a stop valve is arranged on the cross-line pipeline, and the resolved gas in the second gas inlet pipe can be injected into the first gas inlet pipe through the cross-line pipeline to mix with the converted gas.

[0007] Preferably, a booster valve is further arranged on the cross-line pipeline.

[0008] Preferably, the liquid inlet pipe is arranged above the upper layer of the filler, and the liquid outlet pipe is arranged at the bottom of the absorption tower.

[0009] Preferably, the circulating mechanism comprises a regenerator arranged in series with the liquid outlet pipe and the liquid inlet pipe, a reboiler arranged at one side of the regenerator, and a regenerated gas discharge pipe arranged at the top of the regenerator, one end of the liquid outlet pipe is arranged at the upper end of the regenerator, one end of the liquid inlet pipe is arranged at the bottom of the regenerator, a lean-rich liquid heat exchanger is arranged between the liquid outlet pipe and the liquid inlet pipe, and a lean liquid pump is further arranged on the liquid inlet pipe.

[0010] Preferably, a lean liquid cooler is further arranged on the liquid inlet pipe between the lean liquid pump and the lean-rich liquid heat exchanger.

[0011] Preferably, a flash tank is arranged on the liquid outlet pipe between the absorption tower and the lean-rich liquid heat exchanger, and a flash steam discharge pipe is arranged on the flash tank.

[0012] Preferably, a regenerated gas cooler and a regenerated gas separator are arranged on the regenerated gas discharge pipe, a reflux pipe is arranged between the regenerated gas separator and the regenerator, and a reflux pump is arranged on the reflux pipe.

[0013] Compared with the prior art, the utility model has the beneficial effects that:

[0014] By changing the flow of the regenerated gas into different filler layers of the absorption tower, the uneven distribution of gas components in the absorption tower is reduced, the targeted treatment of different concentrations of gas is realized, the problem that the decarbonization effect is not ideal due to the local overlarge concentration of the NCMA solution in the decarbonization process is effectively alleviated, the decarbonization efficiency of the decarbonization absorption tower is more stable and is not easily affected by the operation equipment, the CO2 in the converted gas and the regenerated gas is absorbed, and the CO2 content in the decarbonization gas is ensured to be less than the design value. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The process flow chart of the utility model is shown in the figure;

[0016] In the figure: 1, lean liquid pump; 2, liquid discharge pipe; 3, absorption tower; 4, first gas inlet pipe; 5, booster valve; 6, lower layer filler; 7, stop valve; 8, cross-line pipe; 9, second gas inlet pipe; 10, upper layer filler; 11, purified gas discharge pipe; 12, liquid inlet pipe; 13, flash steam discharge pipe; 14, flash tank; 15, regenerated gas cooler; 16, regenerated gas discharge pipe; 17, regenerated gas separator; 18, reflux pump; 19, regeneration tower; 20, reboiler; 21, lean and rich liquid heat exchanger; 22, lean liquid cooler. DETAILED DESCRIPTION

[0017] In the following, the present application will be further described in conjunction with the drawings and specific embodiments, it should be noted that the following described embodiments or technical features can be combined in any manner to form new embodiments, without conflict.

[0018] In the description of the present application, it should be understood that the terms "upper", "lower", "left", "right" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0019] The terms "first", "second", and the like in the present application are used to distinguish similar objects, and are not used to describe a particular order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than that illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of a kind and do not limit the number of objects, for example, a first object can be one or more. In addition, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / ", generally indicates that the front and rear associated objects are in a "or" relationship.

[0020] As shown in Figure 1 A transformed gas and desorbed gas decarburization regeneration device, comprising an absorption tower 3, a purified gas discharge pipe 11 provided on the absorption tower 3, a liquid discharge pipe 2, a liquid inlet pipe 12, and a first gas inlet pipe 4 and a second gas inlet pipe 9, the absorption tower 3 is a filler absorption tower 3, the absorption tower 3 is provided with an upper layer filler 10 and a lower layer filler 6, the first gas inlet pipe 4 is provided at the lower part of the lower layer filler 6, the second gas inlet pipe 9 is provided at the lower part of the upper layer filler 10, a circulating mechanism for supplying NCMA solution is provided between the liquid discharge pipe 2 and the liquid inlet pipe 12, the transformed gas enters the absorption tower 3 through the first gas inlet pipe 4, the desorbed gas enters the absorption tower 3 through the second gas inlet pipe 9, and the CO2 in the gas in the absorption tower 3 is absorbed by the NCMA solution.

[0021] In actual production process, the absorption tower 3 is a packed absorption tower 3, the absorption tower 3 is filled with upper packing 10 and lower packing 6, the flow mode of gas-liquid two-phase in the absorption tower 3 is countercurrent operation, the NCMA solution absorbent is added from the top and flows downward, and contacts with the gas flowing upward from the bottom, the absorption of carbon dioxide by the NCMA composite amine lean solution in the absorption tower 3 is under high pressure and low temperature conditions, the NCMA composite amine lean solution from the top of the absorption tower 3 contacts with the converted gas and the stripping gas from the bottom of the absorption tower 3 in reverse to perform mass transfer and heat transfer, the CO2 in the raw material gas is absorbed, and the NCMA composite amine lean solution after absorbing CO2 becomes NCMA composite amine rich solution, which is discharged from the liquid discharge pipe 2 at the bottom of the absorption tower 3 and enters the circulation mechanism, and the purified gas is discharged from the purified gas discharge pipe 11 at the top of the tower. When the converted gas and the stripping gas are injected into the absorption tower 3, the first gas inlet pipe 4 is located at the lower part of the lower packing 6, and the second gas inlet pipe 9 is located at the lower part of the upper packing 10, so that the carbon dioxide in the converted gas can be better absorbed through twice packing filtration and longer residence time and rising time, and the stripping gas with low concentration can be directly injected through the second gas inlet pipe 9 after injection, and then filtered through the upper packing 10, by changing the flow of the regenerated gas into different packing layers of the absorption tower 3, the unevenness of the gas components in the absorption tower 3 is reduced, the targeted treatment of different concentrations of gas is realized, the problem of unsatisfactory decarbonization effect caused by local over-concentration of the NCMA solution during decarbonization is effectively alleviated, the decarbonization efficiency of the decarbonization absorption tower 3 is more stable, and is not easily affected by the operation equipment, the CO2 in the converted gas and the regenerated gas is absorbed to ensure that the CO2 content in the decarbonized gas is less than the design value.

[0022] Further improvement is that a cross-line pipeline 8 is provided between the first gas inlet pipe 4 and the second gas inlet pipe 9, the cross-line pipeline 8 is provided with a stop valve 7, and the stripping gas in the second gas inlet pipe 9 can be injected into the first gas inlet pipe 4 through the cross-line pipeline 8 to mix with the converted gas.

[0023] Because the concentration of carbon dioxide in the converted gas is obviously greater than that in the resolved gas, and the total amount of treatment in unit volume of the decarburization absorption tower 3 is constant, when the total amount of the converted gas input is too large, it is difficult to achieve the phenomenon of completely absorbing CO2, ultimately resulting in the purified gas containing CO2, therefore, a cross-line pipeline 8 with a stop valve 7 is added between the first gas inlet pipe 4 and the second gas inlet pipe 9, through the combination of the cross-line pipeline 8 and the stop valve 7, part of the resolved gas can be diverted to the converted gas for dilution and then enter the absorption tower 3 through the first gas inlet pipe 4, thereby changing the gas inlet amount of the upper and lower layers of the packing 6 in the absorption tower 3, and reducing the percentage content of CO2 in unit volume of the converted gas, ensuring complete CO2 purification. Among them, the stop valve 7 also realizes controllable adjustment of the flow of the regenerated gas merged into the converted gas, and different proportional adjustments can be made to the flow of the regenerated gas merged according to different production conditions, thereby optimizing the absorption effect.

[0024] Further improvement is that the cross-line pipeline 8 is also provided with a booster valve 5.

[0025] Through the booster valve 5, the pressure of the resolved gas entering the absorption tower 3 can be greater than the pressure of the converted gas entering the absorption tower 3, thereby avoiding the situation of the converted gas being merged into the resolved gas in reverse.

[0026] Further improvement is that the liquid inlet pipe 12 is arranged above the upper layer of packing 10, and the liquid outlet pipe 2 is arranged at the bottom of the absorption tower 3.

[0027] Specific implementation cases are as follows: the method of merging the regenerated gas into the converted gas to change the gas component of the converted gas is adopted, thereby improving the decarburization efficiency of the converted gas. By opening holes on the regenerated gas pipeline and the converted gas pipeline, connecting the cross-line pipeline 8, the scheme of merging the regenerated gas into the converted gas pipeline is implemented. Before the implementation of the process, the MDEA solution circulation amount of the decarburization absorption tower 3 is 360 Nm 3 / h, which enters the absorption tower 3 from the top and flows from top to bottom, the converted gas amount is 190000 Nm 3 / h, which enters from the lower part of the absorption tower 3 and flows from bottom to top, and the regenerated gas amount is 35000 Nm 3 / h, which enters from the middle part of the absorption tower 3 and flows from bottom to top, and the purified converted gas is discharged from the top. Under this process state, the CO2 in the purified gas at the top outlet is 26 ppm (the design value CO2 < 20 ppm). After the implementation of the process, part of the regenerated gas is merged into the converted gas flow, and after the implementation, the MDEA solution circulation amount of the decarburization absorption tower 3 is 360 Nm 3 / h, which enters the absorption tower 3 from the top and flows from top to bottom, the converted gas amount is 202000 Nm 3 / h, which enters from the lower part of the absorption tower 3 and flows from bottom to top, and the regenerated gas amount is 23000 Nm 3 / h, from the middle of the absorption tower 3, flows from bottom to top, and the purified converted gas is discharged from the top. In this process state, the CO2 content in the purified gas at the top outlet is 17 ppm (the design value CO2<20 ppm). Through the above data comparison, it is found that after using a converted gas and a decarburization regeneration device, the CO2 adsorption effect of the decarburization absorption tower 3 is greatly increased without changing the MDEA circulation amount, the CO2 content in the purified gas at the outlet of the absorption tower 3 is reduced, the qualified rate of the purified gas is ensured, and the risk of CO2 freezing in the subsequent cryogenic separation device is reduced.

[0028] Further improvement is that the circulating mechanism comprises a regeneration tower 19 connected in series through the liquid discharge pipe 2 and the liquid inlet pipe 12, a reboiler 20 arranged on one side of the regeneration tower 19, a regenerated gas discharge pipe 16 arranged at the top of the regeneration tower 19, one end of the liquid discharge pipe 2 is arranged at the upper end of the regeneration tower 19, one end of the liquid inlet pipe 12 is arranged at the bottom of the regeneration tower 19, a lean-rich liquid heat exchanger 21 is arranged between the liquid discharge pipe 2 and the liquid inlet pipe 12, and a lean liquid pump 1 is further arranged on the liquid inlet pipe 12.

[0029] The high-pressure low-temperature of the absorption tower 3 is easy to absorb the NCMA composite amine lean solution, the pressure is 3.4-3.8 MPa, and the temperature is 35-45℃. The high-temperature low-pressure of the regeneration tower 19 is easy to regenerate the NCMA composite amine rich solution, the temperature is about 115℃, and the pressure is about 70KPa. In the production process, the NCMA composite amine lean solution after absorbing CO2 is transported to the upper end of the regeneration tower 19 through the liquid discharge pipe 2, flows downward, is heated by the steam heated reboiler 20 in the process of flowing, and the regenerated gas discharge pipe 16 at the top of the regenerator is discharged outward, and the NCMA composite amine lean solution is heated again, and then is returned to the upper end of the absorption tower 3 through the lean liquid pump 1 along the liquid inlet pipe 12 for repeated use. A lean-rich liquid heat exchanger 21 is arranged between the liquid discharge pipe 2 and the liquid inlet pipe 12, the NCMA composite amine lean solution is cooled by the lean-rich liquid heat exchanger 21, the NCMA composite amine rich solution with lower temperature is heated, the discharge of the CO2 regeneration gas is facilitated, and the cooling of the NCMA composite amine lean solution for use in the absorption tower 3 is facilitated.

[0030] Further improvement is that the lean liquid cooler 22 is further arranged on the liquid inlet pipe 12 between the lean liquid pump 1 and the lean-rich liquid heat exchanger 21.

[0031] Since the temperature of the heated NCMA composite amine lean solution in the regeneration tower 19 is high, it is difficult to reach the required temperature after heat exchange through the lean- rich heat exchanger 21, therefore, a lean liquid cooler 22 is additionally arranged on the liquid inlet pipe 12 between the lean liquid pump 1 and the lean- rich heat exchanger 21, and the NCMA composite amine lean solution is secondarily cooled to about 45℃ through the lean liquid cooler 22, so that the NCMA composite amine lean solution can reach the required temperature for injection into the absorption tower 3.

[0032] Further improvement is that the liquid outlet pipe 2 between the absorption tower 3 and the lean- rich heat exchanger 21 is provided with a flash tank 14, and the flash tank 14 is provided with a flash steam discharge pipe 13.

[0033] Since the NCMA composite amine rich solution discharged from the absorption tower 3 contains certain flash steam, if not discharged in time, it will affect the circulation mechanism, therefore, a flash tank 14 is additionally arranged on the liquid outlet pipe 2 between the absorption tower 3 and the lean- rich heat exchanger 21, and the NCMA composite amine lean solution from the regeneration tower 19 is heat exchanged after being reduced pressure flashed through the flash tank 14 to remove part of the hydrocarbon, and then enters the upper part of the regeneration tower 19, and is in countercurrent contact with the stripping steam generated by the steam reboiler 20 from the bottom of the regeneration tower 19 from top to bottom in the low pressure and high temperature regeneration tower 19 to resolve the remaining CO2, and the flash steam can be discharged in time through the flash steam discharge pipe 13 of the flash tank 14, so as to ensure the circulation stability of the NCMA solution.

[0034] Further improvement is that the regeneration gas discharge pipe 16 is provided with a regeneration gas cooler 15 and a regeneration gas separator 17, the regeneration gas separator 17 is provided with a reflux pipe between the regeneration gas separator 17 and the regeneration tower 19, and the reflux pipe is provided with a reflux pump 18.

[0035] The NCMA solution in the steam can be effectively condensed through the regeneration gas cooler 15 and the regeneration gas separator 17, and then reflows into the regeneration tower 19 through the reflux pipe, so as to avoid the loss of the NCMA solution, and the NCMA solution can be recycled.

[0036] The above embodiments are only preferred embodiments of the present application, and cannot be used to limit the scope of protection of the present application, and any non-essential changes and substitutions made by those skilled in the art on the basis of the present application are within the scope of protection of the present application.

Claims

1. A device for decarbonizing and regenerating converted gas and desorbed gas, characterized in that: The absorption tower (3) includes a purified gas exhaust pipe (11), a drain pipe (2), a liquid inlet pipe (12), a first air inlet pipe (4), and a second air inlet pipe (9) installed on the absorption tower (3). The absorption tower (3) is a packed absorption tower (3). The absorption tower (3) is provided with an upper packing layer (10) and a lower packing layer (6). The first air inlet pipe (4) is located at the lower part of the lower packing layer (6), and the second air inlet pipe (9) is located at the lower part of the upper packing layer (10). A circulation mechanism for supplying NCMA solution is provided between the drain pipe (2) and the liquid inlet pipe (12). The converted gas enters the absorption tower (3) through the first air inlet pipe (4), and the desorbed gas enters the absorption tower (3) through the second air inlet pipe (9). CO2 in the gas in the absorption tower (3) is drawn out by the NCMA solution.

2. The decarbonization and regeneration device for converted gas and desorbed gas according to claim 1, characterized in that: A cross-line pipe (8) is provided between the first intake pipe (4) and the second intake pipe (9). A shut-off valve (7) is provided on the cross-line pipe (8). The desorption gas in the second intake pipe (9) can be injected into the first intake pipe (4) through the cross-line pipe (8) to mix with the conversion gas.

3. The decarbonization and regeneration device for converted gas and desorbed gas according to claim 2, characterized in that: A pressure boosting valve (5) is also provided on the cross-line pipeline (8).

4. The decarbonization and regeneration device for converted gas and desorbed gas according to claim 1, characterized in that: The inlet pipe (12) is located above the upper packing (10), and the outlet pipe (2) is located at the bottom of the absorption tower (3).

5. A decarbonization and regeneration device for converted gas and desorbed gas according to any one of claims 1 to 4, characterized in that: The circulation mechanism includes a regeneration tower (19) connected in series through the drain pipe (2) and the inlet pipe (12), a reboiler (20) located on one side of the regeneration tower (19), and a regeneration gas exhaust pipe (16) located at the top of the regeneration tower (19). One end of the drain pipe (2) is located at the upper end of the regeneration tower (19), and one end of the inlet pipe (12) is located at the bottom of the regeneration tower (19). A lean and rich liquid heat exchanger (21) is provided between the drain pipe (2) and the inlet pipe (12), and a lean liquid pump (1) is also provided on the inlet pipe (12).

6. The decarbonization and regeneration device for converted gas and desorbed gas according to claim 5, characterized in that: A lean liquid cooler (22) is also provided on the inlet pipe (12) between the lean liquid pump (1) and the lean and rich liquid heat exchanger (21).

7. The decarbonization and regeneration device for converted gas and desorbed gas according to claim 6, characterized in that: A flash tank (14) is provided on the drain pipe (2) between the absorption tower (3) and the lean and rich liquid heat exchanger (21), and a flash steam discharge pipe (13) is provided on the flash tank (14).

8. The decarbonization and regeneration device for converted gas and desorbed gas according to claim 7, characterized in that: The regenerated gas exhaust pipe (16) is equipped with a regenerated gas cooler (15) and a regenerated gas separator (17). A return pipe is provided between the regenerated gas separator (17) and the regeneration tower (19), and a return pump (18) is provided on the return pipe.

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