Non-condensable gas discharging system of diphenyl carbonate device

Abstract

A non-condensable gas discharging system of a diphenyl carbonate device comprises a tail gas fan, and an exhaust port of the tail gas fan is communicated with an MPC synthesis tower cooler, a DMC refining tower cooler and a methanol removal tower cooler through pipelines; a gas inlet of the tail gas fan is communicated with a tail cooler outlet of the MPC synthesis tower, a tail cooler outlet of the DMC refining tower and a tail cooler outlet of the methanol removal tower through pipelines; according to the device disclosed by the utility model, the orderly discharge of the non-condensable gas can be realized, so that the influence of the non-condensable gas on the positive pressure rectifying tower of the diphenyl carbonate synthesis device is reduced, and the efficient and long-term operation of the device is realized.

Description

Technical Field

[0001] The utility model relates to a non-condensable gas discharging system for a diphenyl carbonate device. Background Art

[0002] During the synthesis reaction of dimethyl carbonate and phenol to produce diphenyl carbonate, side reactions occur, generating carbon dioxide. When the device operates continuously, the nitrogen and carbon dioxide replaced inside the device will gradually accumulate because they cannot be condensed.

[0003] The reaction formula for the synthesis of diphenyl carbonate from dimethyl carbonate and phenol is as follows:

[0004]

[0005]

[0006] The side reactions are as follows:

[0007]

[0008] Nitrogen and carbon dioxide, as non-condensable gases, affect the volume composition fraction of the rectifying gas phase and the heat exchange at the top of the rectifying column, thus affecting the separation of the rectifying column. When the non-condensable gases accumulate to a certain extent, the temperature difference between the inlet and outlet water temperatures of the condenser cooling water gradually decreases, and the normal gas-phase condensation basic unit cannot operate normally, affecting the operation of the diphenyl carbonate device and resulting in a reduction in the production load of the device. Content of the Utility Model

[0009] The technical problem to be solved by the utility model is to provide a non-condensable gas discharging system for a diphenyl carbonate device, which can achieve the orderly discharge of non-condensable gases, thereby reducing the influence of non-condensable gases on the positive-pressure rectifying column of the diphenyl carbonate synthesis device and realizing the efficient and long-term operation of the device.

[0010] To solve the above problems, the technical solution of the utility model is as follows:

[0011] A non-condensable gas discharging system for a diphenyl carbonate device includes a tail gas fan. The exhaust port of the tail gas fan is connected to the MPC synthesis tower cooler, the DMC refining tower cooler, and the methanol removal tower cooler through pipelines; the intake port of the tail gas fan is connected to the outlet of the MPC synthesis tower aftercooler, the outlet of the DMC refining tower aftercooler, and the outlet of the methanol removal tower aftercooler through pipelines; the exhaust port of the tail gas fan is connected to an incinerator through a pipeline.

[0012] The MPC synthesis tower is sequentially connected to the MPC synthesis tower cooler and the MPC synthesis tower reflux tank. The top of the MPC synthesis tower reflux tank is connected to the inlet of the MPC synthesis tower aftercooler, and the bottom of the MPC synthesis tower reflux tank is connected to the DMC refining tower through the MPC synthesis tower reflux pump.

[0013] The DMC refining tower is successively connected to the DMC refining tower cooler and the DMC refining tower reflux tank. The bottom of the DMC refining tower reflux tank is connected to the methanol removal tower through the DMC refining tower reflux pump.

[0014] The methanol removal tower is successively connected to the methanol removal tower cooler and the methanol removal tower reflux tank. The bottom of the methanol removal tower reflux tank is connected to the outlet of the methanol removal tower tail cooler through a pipeline.

[0015] The beneficial effects of the present utility model are as follows:

[0016] 1. Solve the problem that the non-condensable gas accumulates in the rectifying tower of the device, resulting in a decrease in the condensation load of the rectifying tower.

[0017] 2. The non-condensable gas can be discharged during the production operation process, so as to keep the device running more efficiently for a longer time. Description of the Drawings

[0018] The following further describes the present utility model with reference to the accompanying drawings:

[0019] Figure 1 It is a structural schematic diagram of the present utility model.

[0020] In the figure: MPC synthesis tower 1, MPC synthesis tower cooler 2, MPC synthesis tower reflux tank 3, MPC synthesis tower tail cooler 4, MPC synthesis tower reflux pump 5, DMC refining tower 6, DMC refining tower cooler 7, DMC refining tower reflux tank 8, DMC refining tower tail cooler 9, DMC refining tower reflux pump 10, methanol removal tower 11, methanol removal tower cooler 12, methanol removal tower reflux tank 13, methanol removal tower tail cooler 14, tail gas fan 15, incinerator 16. Specific Embodiments

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0022] As Figure 1 shown, a non-condensable gas discharge system for a diphenyl carbonate device includes a tail gas fan 15. The exhaust port of the tail gas fan 15 is connected to the MPC synthesis tower cooler 2, the DMC refining tower cooler 7, and the methanol removal tower cooler 12 through pipelines; the intake port of the tail gas fan 15 is connected to the outlet of the MPC synthesis tower tail cooler 4, the outlet of the DMC refining tower tail cooler 9, and the outlet of the methanol removal tower tail cooler 14 through pipelines; the exhaust port of the tail gas fan 15 is connected to the incinerator 16 through a pipeline.

[0023] The MPC synthesis tower 1 is successively connected to the MPC synthesis tower cooler 2 and the MPC synthesis tower reflux tank 3. The top of the MPC synthesis tower reflux tank 3 is connected to the inlet of the MPC synthesis tower after-cooler 4. The bottom of the MPC synthesis tower reflux tank 3 is connected to the DMC refining tower 6 through the MPC synthesis tower reflux pump 5.

[0024] The DMC refining tower 6 is successively connected to the DMC refining tower cooler 7 and the DMC refining tower reflux tank 8. The bottom of the DMC refining tower reflux tank 8 is connected to the methanol removal tower 11 through the DMC refining tower reflux pump 10.

[0025] The methanol removal tower 11 is successively connected to the methanol removal tower cooler 12 and the methanol removal tower reflux tank 13. The bottom of the methanol removal tower reflux tank 13 is connected to the outlet of the methanol removal tower after-cooler 14 through a pipeline.

[0026] The working process of the present utility model is as follows:

[0027] In the MPC synthesis tower 1, through evaporation rectification, the light components dimethyl carbonate and methanol are condensed by the MPC synthesis tower cooler 2 and then enter the MPC synthesis tower reflux tank 3. The uncondensed tail gas in the MPC synthesis tower reflux tank 3 is further condensed by the MPC synthesis tower after-cooler 4, and the condensate returns to the MPC synthesis tower reflux tank 3. The uncondensed tail gas enters the tail gas main pipe through the tail gas blower 15 and is sent to the incinerator 16.

[0028] The MPC synthesis tower reflux tank 3 sends the methanol and dimethyl carbonate materials to the DMC refining tower 6 through the MPC synthesis tower reflux pump 5. In the DMC refining tower 6, through evaporation rectification, the dimethyl carbonate and methanol azeotrope are condensed by the DMC refining tower cooler 7 and then enter the DMC refining tower reflux tank 8. The uncondensed tail gas in the DMC refining tower reflux tank 8 is further condensed by the DMC refining tower after-cooler 9, and the condensate returns to the DMC refining tower reflux tank 8. The uncondensed tail gas enters the tail gas main pipe through the tail gas blower 15 and is sent to the incinerator 16.

[0029] The DMC refining tower reflux tank 8 sends the methanol and dimethyl carbonate materials to the methanol removal tower 11 through the DMC refining tower reflux pump 10. In the methanol removal tower 11, through evaporation rectification, the dimethyl carbonate and methanol azeotrope are condensed by the methanol removal tower cooler 12 and then enter the methanol removal tower reflux tank 13. The uncondensed tail gas in the methanol removal tower reflux tank 13 is further condensed by the methanol removal tower after-cooler 14, and the condensate returns to the methanol removal tower reflux tank 13. The uncondensed tail gas enters the tail gas main pipe through the tail gas blower 15 and is sent to the incinerator 16.

[0030] During normal operation, as a side reaction generates carbon dioxide, it accumulates at the tops of the MPC synthesis tower 1, the DMC purification tower 6, and the methanol removal tower 11 together with the nitrogen in the tower. Part of it enters the tail gas main pipe along with the tail gas, passes through the tail gas fan 15 and enters the tail gas main pipe, and then is sent to the incinerator 16. Part of it continues to accumulate at the top. As the accumulation amount increases, the heat exchange capacity of the top cooler and the tail gas condenser gradually decreases, and the opening degrees of the circulating water and chilled water media of the cooler and the condenser gradually increase. Open the valves for discharging non-condensable gas of the MPC synthesis tower cooler 2, the DMC purification tower cooler 7, and the methanol removal tower cooler 12. When the temperature of the condensed liquid of the MPC synthesis tower cooler 2, the DMC purification tower cooler 7, and the methanol removal tower cooler 12 drops, it means that the discharge of non-condensable gas is basically completed.

[0031] The content described in the embodiments of this specification is only an enumeration of the implementation forms of the utility model concept. The protection scope of the utility model should not be regarded as limited to the specific forms stated in the embodiments. The protection scope of the utility model also extends to equivalent technical means that can be conceived by those skilled in the art based on the utility model concept.

Claims

1. A non-condensable gas discharge system for a diphenyl carbonate device, characterized in that: The invention comprises an exhaust fan (15), wherein the exhaust port of the exhaust fan (15) is connected to an MPC synthesis tower cooler (2), a DMC refining tower cooler (7) and a methanol removal tower cooler (12) through a pipeline; the air inlet of the exhaust fan (15) is connected to an MPC synthesis tower tail cooler (4) outlet, a DMC refining tower tail cooler (9) outlet and a methanol removal tower tail cooler outlet (14) through a pipeline; and the exhaust port of the exhaust fan (15) is connected to an incinerator (16) through a pipeline.

2. A non-condensable gas discharge system for a diphenyl carbonate device according to claim 1, characterized in that: The MPC synthesis tower (1) is connected to the MPC synthesis tower cooler (2) and the MPC synthesis tower reflux tank (3) in sequence; the top of the MPC synthesis tower reflux tank (3) is connected to the inlet of the MPC synthesis tower tail cooler (4); and the bottom of the MPC synthesis tower reflux tank (3) is connected to the DMC refining tower (6) through the MPC synthesis tower reflux pump (5).

3. A non-condensable gas discharge system for a diphenyl carbonate device according to claim 2, characterized in that: The DMC refining tower (6) is connected to the DMC refining tower cooler (7) and the DMC refining tower reflux tank (8) in sequence, and the bottom of the DMC refining tower reflux tank (8) is connected to the methanol removal tower (11) through the DMC refining tower reflux pump (10).

4. A non-condensable gas discharge system for a diphenyl carbonate device according to claim 3, characterized in that: The methanol removal tower (11) is connected to the methanol removal tower cooler (12) and the methanol removal tower reflux tank (13) in sequence, and the bottom of the methanol removal tower reflux tank (13) is connected to the methanol removal tower tail cooler outlet (14) through a pipeline.

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