A tail gas recovery device for dimethyl carbonate used in vinylene carbonate production

Abstract

A tail gas recovery device for dimethyl carbonate used in the production of vinylene carbonate, the device comprises a shell, a thickened heat insulation layer is provided at the lower part of the shell, an air inlet is provided at the bottom of the shell, a third valve is installed on the air inlet, an air outlet is provided at the lower part of the shell, a fourth valve is installed at the air outlet; a partition is provided at the upper part of the shell, a cooling air outlet is provided at the top of the shell, a cooling air inlet is provided above the shell, the cooling air inlet is connected to the air outlet through a cooling pipeline, a second check valve is installed on the cooling pipeline, the cooling air outlet is connected to a transition tank through a pipeline, a discharge pipeline is connected to the bottom of the transition tank, a vacuum pump is installed on the discharge pipeline, a discharge valve is installed on the combustion device, the discharge pipeline is connected to the cooling pipeline through a reflux pipeline, and a first check valve is installed on the reflux pipeline. The utility model can realize sufficient cooling and condensation of tail gas, so that methanol in the tail gas can be fully recovered, reducing material consumption and saving production costs.

Description

Technical Field

[0001] The utility model is applicable to the technical field of tail gas recovery and provides a tail gas recovery device for dimethyl carbonate used in the production of vinylene carbonate. Background Art

[0002] Dimethyl carbonate is needed in the production of vinylene carbonate. In the production process of dimethyl carbonate, propylene oxide and carbon dioxide are generally used to add a catalyst at 0.6 MPa and 170 degrees Celsius to obtain crude propylene carbonate, which is purified by negative pressure distillation to obtain refined propylene carbonate. A large amount of waste gas is generated at this time. In the second step, propylene carbonate and methanol coexist with sodium methoxide at 1.0 MPa to react to generate dimethyl carbonate. The dimethyl carbonate and methanol azeotrope are removed by a distillation tower and propylene glycol is recovered. The unreacted propylene carbonate and methanol are recycled. A large amount of methanol waste gas is generated during the vacuum distillation of propylene glycol. The waste gas is sent to a combustion device for discharge after recovery. However, in the prior art, the waste gas is recovered under cooling conditions, but the cooling process of the tail gas cannot be fully cooled, so that part of the methanol is still contained in the exhaust gas, so that the methanol cannot be fully recovered, resulting in excessive consumption of methanol. Utility Model Content

[0003] In view of the above-mentioned defects, the purpose of the utility model is to provide a tail gas recovery device for dimethyl carbonate used in the production of vinylene carbonate, the device comprising a shell, a thickened heat insulation layer is provided at the lower part of the shell, an air inlet is provided at the bottom of the shell, a third valve is installed on the air inlet, an air outlet is provided at the lower part of the shell, a fourth valve is installed on the air outlet, and the air outlet is located below the thickened heat insulation layer; a partition is provided at the upper part of the shell, a cooling air outlet is provided at the top of the shell, a cooling air inlet is provided above the shell, the cooling air inlet is connected to the air outlet through a cooling pipeline, the portion of the cooling pipeline extending into the shell is in a downwardly bent shape, a second check valve is installed on the cooling pipeline, the pipe opening of the cooling pipeline inside the shell is close to the partition, the cooling air outlet is connected to a transition tank through a pipeline, the bottom of the transition tank is connected to a discharge pipeline, a vacuum pump is installed on the discharge pipeline, a discharge valve is installed on the combustion device, the discharge pipeline is connected to the cooling pipeline through a reflux pipeline, and a first check valve is installed on the reflux pipeline.

[0004] Furthermore, an ammonia cooling inlet is provided on the upper part of the shell, and a first valve is installed on the ammonia cooling inlet. The shell is provided with an ammonia cooling outlet, and the ammonia cooling outlet is above the ammonia cooling inlet. A coil matching the ammonia cooling inlet and the ammonia cooling outlet is installed in the shell, and the coil is above the partition.

[0005] Furthermore, the partition is provided with a coolant outlet, and the coolant outlet is installed with a second valve.

[0006] Furthermore, a discharge port is provided at the lower portion of the shell, and the discharge port is between the partition and the thickened insulation layer.

[0007] Furthermore, the shell is equipped with a temperature sensor, the temperature sensor is above the partition, and the temperature sensor is electrically connected to the controller.

[0008] Furthermore, a methanol detector is installed in the transition tank, and the methanol detector is electrically connected to the controller.

[0009] Furthermore, a heat-insulating layer is installed on the inner wall of the shell.

[0010] Furthermore, the exhaust pipe is connected to a combustion device.

[0011] Furthermore, a wire mesh demister is installed on the top of the shell.

[0012] The beneficial effects of the utility model are as follows: the utility model can achieve sufficient cooling and condensation of the tail gas by arranging a transition tank and a reflux pipe, so that the methanol in the tail gas can be fully recovered, reducing material consumption, saving production costs, and at the same time increasing the insulation layer so that the cold in the device is not easily lost. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the structure of a tail gas recovery device for dimethyl carbonate used in the production of vinylene carbonate;

[0014] In the figure: 1. Cooling air outlet; 2. Wire mesh demister; 3. Ammonia cooling outlet; 4. Temperature sensor; 5. Coil; 6. Ammonia cooling inlet; 7. Cooling liquid outlet; 9. Discharge port; 10. Discharge port; 11. Insulation layer; 12. Air inlet; 13. Transition tank; 14. Methanol detector; 15. Vacuum pump; 16. Discharge pipe; 17. Combustion device; 18. Discharge valve; 19. First check valve; 20. Cooling air inlet; 21. Second check valve; 22. Cooling pipeline; 23. Air outlet; 24. Thickened insulation layer; 25. Partition. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0016] See also Figure 1The utility model aims to provide a tail gas recovery device for dimethyl carbonate used in the production of vinylene carbonate, comprising a shell 10, a thickened thermal insulation layer 24 is provided at the lower part of the shell 10, the thickened thermal insulation layer 24 separates the shell 10, the lower part of the thickened thermal insulation layer 24 is used as a gas storage tank, and the upper part of the thickened thermal insulation layer 24 is used as a liquid storage tank, an air inlet 12 is provided at the bottom of the shell 10, a third valve is installed on the air inlet 12, and the required recovered gas can be injected into the device through the air inlet 12, an air outlet 23 is provided at the lower part of the shell 10, a fourth valve is installed at the air outlet 23, the air outlet 23 is located below the thickened thermal insulation layer 24, the air outlet 23 is used to discharge the gas below the thickened thermal insulation layer 24 of the shell 10, and the outlet speed can be controlled by controlling the opening degree of the fourth valve.

[0017] A partition 25 is provided on the upper part of the shell 10, the lower part of the partition 25 is used as a liquid storage tank, and the upper part of the partition 25 is used as a condensation tank; a cooling air outlet 1 is provided on the top of the shell 10, and a fifth valve is installed on the cooling air outlet 1. The cooling air outlet 1 can discharge the condensed gas out of the shell 10. A cooling air inlet 20 is provided on the upper part of the shell 10, and the cooling air inlet 20 is connected to the air outlet 23 through a cooling pipeline 22. The cooling pipeline 22 can transmit the gas from below the thickened insulation layer 24 in the shell 10 to above the partition 25. The part of the cooling pipeline 22 extending into the shell 10 is in a downwardly bent shape, and the pipe mouth of the cooling pipeline 22 inside the shell 10 is close to the partition 25, so that the incoming gas can be fully cooled from bottom to top, and a second check valve 21 is installed on the cooling pipeline 22, and the second check valve 21 can prevent gas backflow.

[0018] The cooling gas outlet 1 is connected to a transition tank 13 through a pipeline, a methanol detector 14 is installed in the transition tank 13, and the methanol detector 14 is electrically connected to the controller. The gas coming out of the shell 10 first passes through the transition tank 13, and the methanol content in the gas is detected by the methanol detector 14; the bottom of the transition tank 13 is connected to a discharge pipe 16, and a vacuum pump 15 is installed on the discharge pipe 16. The vacuum pump 15 can provide power for the flow of gas. A discharge valve 18 is installed on the combustion device 17. The discharge pipe 16 is connected to the cooling pipeline 22 through a reflux pipe 26. A first check valve 19 is installed on the reflux pipe 26. When the methanol detector 14 detects that the gas meets the standard, it transmits a signal to the controller, and the controller controls the discharge valve 18 to open directly, so that the remaining gas is directly discharged. When the methanol detector 14 detects that the gas does not meet the standard, the discharge valve 18 is closed, so that the gas re-enters the shell 10 through the reflux pipe 26 and the cooling pipeline 22 for cooling, so as to achieve sufficient cooling of the gas and allow the methanol to be fully recovered.

[0019] The upper part of the shell 10 is provided with an ammonia cooling inlet 6, and the ammonia cooling inlet 6 is installed with a first valve. The shell 10 is provided with an ammonia cooling outlet 3, and the ammonia cooling outlet 3 is above the ammonia cooling inlet 6. The shell 10 is provided with a coil 5 that matches the ammonia cooling inlet 6 and the ammonia cooling outlet 3, and the coil 5 is above the partition 25. The shell 10 is installed with a temperature sensor 4, and the temperature sensor 4 is above the partition 25. The temperature sensor 4 is electrically connected to a controller, and the temperature sensor 4 can detect temperature. The first valve can be adjusted according to the detected temperature, and the amount of ammonia cooling liquid inlet can be controlled by adjusting the opening degree of the first valve, thereby controlling When the temperature reaches a suitable range, the ammonia cooling fully cools the inside of the shell 10 through the coil 5, so that the methanol gas carried in the gas can be cooled and condensed to form methanol liquid retained above the partition 25; the partition 25 is provided with a coolant outlet 7, and the coolant outlet 7 is installed with a second valve. When the cooling and condensation process is completed, the second valve can be opened to discharge the coolant to the bottom of the partition 25 for storage; the lower part of the shell 10 is provided with a discharge port 9, and the discharge port 9 is between the partition 25 and the thickened insulation layer 24. The stored coolant can be discharged to the outside of the shell 10 through the discharge port 9 and transported to the corresponding section for storage and use.

[0020] The inner wall of the shell 10 is provided with an insulation layer 11 , and the insulation layer 11 can insulate the overall temperature inside the shell 10 to avoid the loss of cold.

[0021] The exhaust pipe 16 is connected to a combustion device 17. When the cooled gas reaches the standard, it is directly discharged to the combustion device 17 for combustion treatment. After the gas is burned, it can meet the emission standard.

[0022] A wire mesh demister 2 is disposed on the top of the shell 10, and the wire mesh demister 2 can block the liquid brought by the rising gas to prevent the exhaust gas from carrying too much liquid components.

[0023] To sum up, in actual use, the required recovered gas enters the shell 10 from the air inlet 12, enters the shell 10 above the partition 25 through the air outlet 23 and the cooling pipeline 22 for cooling, and the cooled gas flows to the transition tank 13 through the cooling gas outlet 1. When the methanol detector 14 in the transition tank 13 detects that the gas concentration does not meet the standard, the discharge valve 18 is closed, and the gas returns to the shell 10 through the cooling pipeline 22 through the reflux pipe 26 for repeated cooling. When the gas detected by the methanol detector 14 meets the standard, the discharge valve 18 is opened to allow the gas to be transported to the combustion device 17 through the discharge pipe 16 for combustion.

[0024] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A tail gas recovery device for dimethyl carbonate used in the production of vinylene carbonate, characterized in that: The invention comprises a combustion device (17) and a shell (10), wherein a thickened heat insulation layer (24) is provided at the bottom of the shell (10), an air inlet (12) is provided at the bottom of the shell (10), a third valve is installed on the air inlet (12), an air outlet (23) is provided at the bottom of the shell (10), a fourth valve is installed at the air outlet (23), and the air outlet (23) is located below the thickened heat insulation layer (24); a partition (25) is provided at the top of the shell (10), a cooling air outlet (1) is provided at the top of the shell (10), a cooling air inlet (20) is provided at the top of the shell (10), and the cooling air inlet (20) is connected to the air outlet (23) via a cooling pipeline (22). 3), the portion of the cooling pipeline (22) extending into the shell (10) is in a downwardly bent shape, a second check valve (21) is installed on the cooling pipeline (22), the pipe opening of the cooling pipeline (22) inside the shell (10) is close to the partition (25), the cooling gas outlet (1) is connected to the transition tank (13) through a pipeline, the bottom of the transition tank (13) is connected to the discharge pipeline (16), a vacuum pump (15) is installed on the discharge pipeline (16), the combustion device (17) is installed with a discharge valve (18), the discharge pipeline (16) is connected to the cooling pipeline (22) through a return pipeline (26), and the return pipeline (26) is installed with a first check valve (19).

2. The tail gas recovery device for dimethyl carbonate used in the production of vinylene carbonate according to claim 1, characterized in that: An ammonia cooling inlet (6) is provided at the upper portion of the shell (10), and a first valve is installed at the ammonia cooling inlet (6). An ammonia cooling outlet (3) is provided at the shell (10), and the ammonia cooling outlet (3) is above the ammonia cooling inlet (6). A coil (5) matching the ammonia cooling inlet (6) and the ammonia cooling outlet (3) is installed in the shell (10), and the coil (5) is above the partition (25).

3. The tail gas recovery device for dimethyl carbonate used in vinylene carbonate production according to claim 1, characterized in that: The partition plate (25) is provided with a coolant outlet (7), and the coolant outlet (7) is equipped with a second valve.

4. The tail gas recovery device for dimethyl carbonate used in vinylene carbonate production according to claim 1, characterized in that: A discharge port (9) is provided at the lower portion of the shell (10), and the discharge port (9) is between the partition plate (25) and the thickened heat insulation layer (24).

5. The tail gas recovery device for dimethyl carbonate used in vinylene carbonate production according to claim 1, characterized in that: The housing (10) is installed with a temperature sensor (4), the temperature sensor (4) is above the partition (25), and the temperature sensor (4) is electrically connected to a controller.

6. The tail gas recovery device for dimethyl carbonate used in vinylene carbonate production according to claim 1, characterized in that: A methanol detector (14) is installed in the transition tank (13), and the methanol detector (14) is electrically connected to a controller.

7. The tail gas recovery device for dimethyl carbonate used in vinylene carbonate production according to claim 1, characterized in that: A heat-insulating layer (11) is installed on the inner wall of the shell (10).

8. The tail gas recovery device for dimethyl carbonate used in vinylene carbonate production according to claim 1, characterized in that: The exhaust pipe (16) is connected to a combustion device (17).

9. The tail gas recovery device for dimethyl carbonate used in vinylene carbonate production according to claim 1, characterized in that: A wire mesh demister (2) is installed at the top of the housing (10).

Images