Low-temperature methanol washing high-purity low-pressure CO2 gas recycling system

Abstract

The utility model discloses a low temperature methanol washing high purity low pressure CO2 gas recycling system, including magnetic suspension centrifugal type carbon dioxide gas compressor, magnetic suspension centrifugal type carbon dioxide gas compressor gas phase import end is connected with the export of import gas separator, import gas separator gas phase import end is connected with low temperature methanol washing shift gas cooler's high purity low pressure CO2 gas export in proper order through third pipeline, first pipeline, the export of gas cooling heat exchanger is connected to the import of urea carbon dioxide compressor on one total pipe with magnetic suspension centrifugal type carbon dioxide gas compressor gas phase export end through second pipeline, and the export of gas cooling heat exchanger is connected to the import of urea carbon dioxide compressor on one total pipe, compared with prior art, the utility model has solved the problem that low temperature methanol washing device low pressure high purity CO2 gas is vented to the atmosphere, namely pollutes the environment and causes the problem of waste. The production efficiency of space furnace device and urea production device is improved.

Description

Technical Field

[0001] This utility model relates to the field of gas recovery and utilization technology, specifically a low-temperature methanol washing high-purity low-pressure CO2 gas recovery and utilization system. Background Technology

[0002] According to the requirements of new coal chemical and urea production processes, in the current technology, the gas used for urea production is CO2 product gas (pressure: 0.16-0.20 MPa, CO2 purity: ≥98.5%, total sulfur: ≤10 ppm) produced by the desorption of sulfur-free methanol liquid. Meanwhile, the higher purity low-pressure CO2 gas (CO2: 99.978%, H2S: 0%, H2: 0.0059%, CH3OH: 0.0127%, pressure: 0.055 MPa) produced by the desorption of sulfur-free methanol liquid is reheated in a shift gas cooler and then sent to a tail gas scrubbing tower. After being washed with demineralized water, it is directly discharged into the atmosphere. This not only pollutes the surrounding environment but also wastes valuable gas. Therefore, this invention proposes a low-temperature methanol washing high-purity low-pressure CO2 gas recovery and utilization system. Utility Model Content

[0003] The purpose of this invention is to provide a low-temperature methanol washing system for the recovery and utilization of high-purity, low-pressure CO2 gas, in order to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, this utility model provides the following technical solution: a low-temperature methanol washing high-purity low-pressure CO2 gas recovery and utilization system, comprising a magnetically levitated centrifugal carbon dioxide compressor, wherein the gas phase inlet end of the magnetically levitated centrifugal carbon dioxide compressor is connected to the outlet end of an inlet gas separator, the gas phase inlet end of the inlet gas separator is sequentially connected to the high-purity low-pressure CO2 gas outlet end of a low-temperature methanol washing converter via a third pipeline and a first pipeline, the gas phase outlet end of the magnetically levitated centrifugal carbon dioxide compressor is connected to the inlet end of a gas cooling heat exchanger via a second pipeline, and the outlet end of the gas cooling heat exchanger is connected to a main inlet pipe of a urea carbon dioxide compressor.

[0005] As a preferred technical solution of this utility model, a first outlet valve is provided on the first pipeline.

[0006] As a preferred technical solution of this utility model, the first pipeline is provided with a tail gas scrubbing tower vent pipeline, and a remote DCS regulating valve is provided on the tail gas scrubbing tower vent pipeline.

[0007] As a preferred technical solution of this utility model, the third pipeline is provided with a remote electric control valve and a vent pipe, and the vent pipe is provided with a remote automatic electric vent valve.

[0008] As a preferred technical solution of this utility model, the second pipeline is provided with an automatic overpressure venting regulating valve group, and the outlet end of the gas cooling heat exchanger is connected to a main inlet pipe of the urea carbon dioxide compressor through a fourth pipeline, and the fourth pipeline is provided with an outlet check valve and a second outlet valve.

[0009] As a preferred technical solution of this utility model, the inter-stage gas cooling of the magnetic levitation centrifugal carbon dioxide gas compressor is achieved by a circulating water cooling device. The circulating water cooling device includes a circulating water outlet pipe and a circulating water inlet pipe connected to the circulating water pump. A circulating water inlet branch pipe is provided on one side of the circulating water inlet pipe. A circulating water filter is provided on the circulating water inlet pipe. A branch valve is provided on the circulating water inlet branch pipe. A third outlet valve is provided on the circulating water outlet pipe.

[0010] As a preferred technical solution of this utility model, the gas cooling heat exchanger tube side is provided with a heat exchange circulation inlet pipe and a heat exchange circulation outlet pipe, and the heat exchange circulation inlet pipe is provided with a first inlet valve, and the heat exchange circulation outlet pipe is provided with a fourth outlet valve.

[0011] Compared with the prior art, the beneficial effects of this utility model are:

[0012] This invention relates to a low-temperature methanol washing high-purity, low-pressure CO2 gas recovery and utilization system. It utilizes a magnetically levitated centrifugal carbon dioxide compressor to pressurize the low-pressure, high-purity CO2 gas (CO2: 99.978%, H2S: 0%, H2: 0.0059%, CH3OH: 0.0127%, pressure: 0.055 MPa) vented from the low-temperature methanol washing unit. The pressure is increased from 0.055 MPa to 0.20-0.25 MPa, and the recovered gas is fed into the inlet of the first stage of the urea carbon dioxide compressor for use in urea production. The required CO2 concentration is 371 NM for producing one ton of urea. 3 The energy-saving effect is considerable when calculated per hour, thus achieving the goal of energy saving and efficiency improvement.

[0013] Other features and advantages of this invention will be described in detail in the following specific embodiments. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0015] In the diagram: 1. Magnetic levitation centrifugal carbon dioxide compressor; 2. Inlet gas separator; 3. Shift gas cooler; 4. First outlet valve; 5. Remote DCS regulating valve; 6. Remote electric control valve; 7. Gas cooling heat exchanger; 8. Remote automatic electric vent valve; 9. Automatic overpressure vent regulating valve group; 10. Outlet check valve; 11. Second outlet valve; 12. Circulating water filter; 13. Branch valve; 14. Third outlet valve; 15. First inlet valve; 16. Fourth outlet valve; 17. Main inlet pipe of urea carbon dioxide compressor; 18. Circulating water pump; 21. First pipeline; 22. Vent pipeline to tail gas scrubbing tower; 23. Third pipeline; 24. Vent pipe; 25. Second pipeline; 26. Fourth pipeline; 27. Circulating water outlet pipe; 28. Circulating water inlet pipe; 29. ​​Circulating water inlet branch pipe. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] In the description of this utility model, it should be noted that the terms "vertical", "up", "down", "horizontal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0018] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0019] Please see Figure 1In this embodiment, a low-temperature methanol washing high-purity low-pressure CO2 gas recovery and utilization system is provided, including a magnetic levitation centrifugal carbon dioxide compressor 1. The gas phase inlet of the magnetic levitation centrifugal carbon dioxide compressor 1 is connected to the outlet of the inlet gas separator 2. The gas phase inlet of the inlet gas separator 2 is connected to the high-purity low-pressure CO2 gas outlet of the low-temperature methanol washing converter 3 through a third pipeline 23 and a first pipeline 21 in sequence. The gas phase outlet of the magnetic levitation centrifugal carbon dioxide compressor 1 is connected to the inlet of the gas cooling heat exchanger 7 through a second pipeline 25. The outlet of the gas cooling heat exchanger 7 is connected to a main inlet pipe 17 of the urea carbon dioxide compressor. A first outlet valve 4 is provided on the first pipeline 21 for starting and stopping this high-purity low-pressure CO2 gas recovery and utilization system. A tail gas scrubbing tower venting pipeline 22 is provided on the first pipeline 21, and a remote DCS regulating valve 5 is provided on the tail gas scrubbing tower venting pipeline 22 for controlling the venting air volume of the tail gas scrubbing tower and the high-purity low-pressure CO2 pressure.

[0020] In this embodiment, the third pipeline 23 is equipped with a remote-controlled electric valve 6 and a vent pipe 24, and the vent pipe 24 is equipped with a remote automatic electric vent valve 8 to realize remote DCS control operation. Simultaneously, a remote automatic electric vent valve 8 is installed at the gas phase inlet of the gas separator 2 to control and prevent overpressure of the high-purity low-pressure CO2 gas at the outlet of the shift gas cooler 3, ensuring stable production and equipment safety at the low-temperature methanol washing station. The pressure of the high-purity low-pressure CO2 gas at the outlet of the shift gas cooler 3 is controlled between 0.050-0.60 MPa.

[0021] In this embodiment, an automatic overpressure venting regulating valve group 9 is provided on the second pipeline 25. The automatic overpressure venting regulating valve group 9 includes multiple automatic regulating valves connected in series to protect the safe operation of the magnetic levitation centrifugal carbon dioxide compressor. The outlet end of the gas cooling heat exchanger 7 is connected to a main inlet pipe 17 of the urea carbon dioxide compressor through the fourth pipeline 26. The fourth pipeline 26 is provided with an outlet check valve 10 and a second outlet valve 11. The outlet gas pressure of the magnetic levitation centrifugal carbon dioxide compressor is controlled at 0.2-0.25 MPa.

[0022] In this embodiment, the inter-stage gas cooling of the magnetic levitation centrifugal carbon dioxide compressor 1 is achieved by a circulating water cooling device. The circulating water cooling device includes a circulating water outlet pipe 27 and a circulating water inlet pipe 28 connected to the circulating water pump 18. A circulating water inlet branch pipe 29 is provided on one side of the circulating water inlet pipe 28 in parallel with it. A circulating water filter 12 is provided on the circulating water inlet pipe 28. A branch valve 13 is provided on the circulating water inlet branch pipe 29. A third outlet valve 14 is provided on the circulating water outlet pipe 27.

[0023] In this embodiment, the gas cooling heat exchanger 7 has a heat exchange circulation inlet pipe and a heat exchange circulation outlet pipe on its tube side, and the heat exchange circulation inlet pipe is equipped with a first inlet valve 15, and the heat exchange circulation outlet pipe is equipped with a fourth outlet valve 16.

[0024] This invention utilizes a magnetically levitated centrifugal carbon dioxide compressor to pressurize low-pressure, high-purity CO2 gas (CO2: 99.978%, H2S: 0%, H2: 0.0059%, CH3OH: 0.0127%, pressure: 0.055 MPa) vented from a low-temperature methanol washing unit. The pressure is increased from 0.055 MPa to 0.20-0.25 MPa, and then recovered to the inlet of the first stage of the urea carbon dioxide compressor for use in urea production. The required CO2 concentration is 371 NM for producing one ton of urea. 3 The energy-saving effect is considerable when calculated per hour, thus achieving the goal of energy saving and efficiency improvement.

[0025] This technology solves the problem of releasing low-pressure, high-purity CO2 gas into the atmosphere from low-temperature methanol washing units, which pollutes the environment and causes waste. It improves the production efficiency of aerospace furnace units and urea production units.

[0026] In summary, this utility model has a simple principle and process, is easy to install and use, and makes full use of the process principle of pressurization, circulating water cooling, and recycling.

[0027] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A low-temperature methanol washing system for recovering and utilizing high-purity, low-pressure CO2 gas, characterized in that, The system includes a magnetically levitated centrifugal carbon dioxide compressor (1), the gas phase inlet of which is connected to the outlet of an inlet gas separator (2), the gas phase inlet of which is connected in sequence to the high-purity low-pressure CO2 gas outlet of a low-temperature methanol wash-change gas cooler (3) via a third pipeline (23) and a first pipeline (21), the gas phase outlet of which is connected to the inlet of a gas cooling heat exchanger (7) via a second pipeline (25), and the outlet of the gas cooling heat exchanger (7) is connected to a main inlet pipe (17) of a urea carbon dioxide compressor.

2. The low-temperature methanol washing high-purity low-pressure CO2 gas recovery and utilization system according to claim 1, characterized in that, The first pipeline (21) is equipped with a first outlet valve (4).

3. The low-temperature methanol washing high-purity low-pressure CO2 gas recovery and utilization system according to claim 1, characterized in that, The first pipeline (21) is equipped with a tail gas scrubbing tower vent pipeline (22), and a remote DCS regulating valve (5) is installed on the tail gas scrubbing tower vent pipeline (22).

4. The low-temperature methanol washing high-purity low-pressure CO2 gas recovery and utilization system according to claim 1, characterized in that, The third pipeline (23) is equipped with a remote electric control valve (6) and a vent pipe (24), and the vent pipe (24) is equipped with a remote automatic electric vent valve (8).

5. The low-temperature methanol washing high-purity low-pressure CO2 gas recovery and utilization system according to claim 1, characterized in that, The second pipeline (25) is equipped with an automatic overpressure venting regulating valve group (9), and the outlet end of the gas cooling heat exchanger (7) is connected to a main inlet pipe (17) of the urea carbon dioxide compressor through the fourth pipeline (26). The fourth pipeline (26) is equipped with an outlet check valve (10) and a second outlet valve (11).

6. The low-temperature methanol washing high-purity low-pressure CO2 gas recovery and utilization system according to claim 1, characterized in that, The inter-stage gas cooling of the magnetic levitation centrifugal carbon dioxide compressor (1) is achieved by a circulating water cooling device. The circulating water cooling device includes a circulating water outlet pipe (27) and a circulating water inlet pipe (28) connected to the circulating water pump (18). A circulating water inlet branch pipe (29) is provided on one side of the circulating water inlet pipe (28) in parallel with it. A circulating water filter (12) is provided on the circulating water inlet pipe (28). A branch valve (13) is provided on the circulating water inlet branch pipe (29). A third outlet valve (14) is provided on the circulating water outlet pipe (27).

7. The low-temperature methanol washing high-purity low-pressure CO2 gas recovery and utilization system according to claim 1, characterized in that, The gas cooling heat exchanger (7) is provided with a heat exchange circulation inlet pipe and a heat exchange circulation outlet pipe on the tube side, and a first inlet valve (15) is provided on the heat exchange circulation inlet pipe, and a fourth outlet valve (16) is provided on the heat exchange circulation outlet pipe.

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