Device for producing dimethyl carbonate

Abstract

The utility model relates to a device for producing dimethyl carbonate. The device comprises a reaction tower, a high-pressure tower, an atmospheric tower, a reaction tower condenser, a reaction tower reflux tank, a reaction tower reflux pump, a reaction tower compressor, a high-pressure tower reboiler, an atmospheric tower condenser, an atmospheric tower reflux tank, an atmospheric tower reflux pump and an atmospheric tower compressor. Distilling materials at the top of the reaction tower and the normal-pressure tower are not condensed, are pressurized by a compressor in a gas phase state, and then enter a high-pressure tower to be separated, so as to obtain a dimethyl carbonate crude product. According to the utility model, the consumption of steam and circulating water in the production process can be reduced, and the production energy consumption and the production cost are reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of carbonate production, in particular to a device for producing dimethyl carbonate. Background Art

[0002] Dimethyl carbonate is an important organic synthesis intermediate. As a green chemical, it is widely used in chemical fields such as polycarbonate, pharmaceutical pesticides, adhesives, electrolytes, coatings, etc., and has broad development and application prospects.

[0003] In a conventional dimethyl carbonate production device, propylene carbonate / ethylene carbonate, methanol and a catalyst react and distill in a reaction tower, and a mixture of methanol and dimethyl carbonate obtained at the top of the tower is separated by a high-pressure tower and a normal pressure tower to obtain crude methanol and dimethyl carbonate. The gaseous mixture of methanol and dimethyl carbonate obtained at the top of the reaction tower is condensed, and part of it enters the high-pressure tower as a tower top distillate in a liquid phase for separation. The azeotropic composition of methanol and dimethyl carbonate changes under high pressure. The crude dimethyl carbonate obtained in the high-pressure tower bottom is further refined. The gaseous mixture of methanol and dimethyl carbonate at the top of the high-pressure tower is partially extracted to the normal pressure tower after heat exchange. After separation in the normal pressure tower, the methanol is recovered in the normal pressure tower bottom. The gaseous mixture of methanol and dimethyl carbonate at the top of the normal pressure tower is condensed by a condenser, and part of it enters the high-pressure tower as a tower top distillate in a liquid phase state for further distillation. During the whole process, the mixture of methanol and dimethyl carbonate is continuously circulated in the system, and the production process consumes a large amount of steam and circulating water, with high production energy consumption and high production costs. Summary of the invention

[0004] In view of the shortcomings of the above situation, the utility model proposes a device for producing dimethyl carbonate, which consumes less steam and circulating water, reduces production energy consumption and production costs, and meets product quality requirements, fully meeting the production requirements of dimethyl carbonate.

[0005] The utility model discloses a device for producing dimethyl carbonate, and the technical scheme is as follows: a device for producing dimethyl carbonate, comprising a reaction tower (T1), a high-pressure tower (T2), a normal-pressure tower (T3), a reaction tower condenser (E1), a reaction tower reflux tank (V1), a reaction tower reflux pump (P1), a reaction tower compressor (P2), a high-pressure tower reboiler (E2), a normal-pressure tower condenser (E3), a normal-pressure tower reflux tank (V2), a normal-pressure tower reflux pump (P3), and a normal-pressure tower compressor (P4), wherein the reaction tower The inlet of the reaction tower (T1) is connected to the raw material feed pipeline, the gas phase outlet at the top of the reaction tower (T1) is connected to the gas phase inlet of the reaction tower condenser (E1), the liquid phase outlet of the reaction tower condenser (E1) is connected to the liquid phase inlet of the reaction tower reflux tank (V1), the gas phase outlet of the reaction tower condenser (E1) is connected to the non-condensable gas system, the liquid phase outlet of the reaction tower reflux tank (V1) is connected to the inlet of the reaction tower reflux pump (P1), the outlet of the reaction tower reflux pump (P1) is connected to the reflux inlet of the reaction tower (T1), the gas phase outlet at the top of the reaction tower (T1) is connected to the reaction tower compressor The inlet of the reactor (P2) is connected to the inlet of the high-pressure tower (T2), the outlet of the reaction tower compressor (P2) is connected to the inlet of the high-pressure tower (T2), the liquid phase outlet of the bottom of the high-pressure tower (T2) is connected to the cold side inlet of the high-pressure tower reboiler (E2), the cold side outlet of the high-pressure tower reboiler (E2) is connected to the bottom of the high-pressure tower (T2), the liquid phase outlet of the bottom of the high-pressure tower (T2) is connected to the crude dimethyl carbonate discharge pipeline, the top gas phase pipeline of the high-pressure tower (T2) is connected to the heat exchanger, the inlet of the atmospheric pressure tower (T3) is connected to the feed pipeline, and the top gas phase outlet of the atmospheric pressure tower (T3) is connected to the atmospheric pressure tower condenser The gas phase inlet of the atmospheric tower condenser (E3) is connected, the liquid phase outlet of the atmospheric tower condenser (E3) is connected to the liquid phase inlet of the atmospheric tower reflux tank (V2), the gas phase outlet of the atmospheric tower condenser (E3) is connected to the non-condensable gas system, the liquid phase outlet of the atmospheric tower reflux tank (V2) is connected to the inlet of the atmospheric tower reflux pump (P3), the outlet of the atmospheric tower reflux pump (P3) is connected to the reflux inlet of the atmospheric tower (T3), the gas phase outlet at the top of the atmospheric tower (T3) is connected to the inlet of the atmospheric tower compressor (P4), and the outlet of the atmospheric tower compressor (P4) is connected to the inlet of the high-pressure tower (T2).

[0006] Preferably, a reaction tower pressure gauge (e) is provided at the top of the reaction tower (T1), a reaction tower condenser regulating valve (c) is provided on the pipeline from the gas phase outlet at the top of the reaction tower (T1) to the gas phase inlet of the reaction tower condenser (E1), and an instrument control interlock is provided between the reaction tower condenser regulating valve (c) and the reaction tower pressure gauge (e).

[0007] Preferably, a reaction tower compressor regulating valve (d) is provided on the pipeline from the gas phase outlet at the top of the reaction tower (T1) to the inlet of the reaction tower compressor (P2), the reaction tower compressor (P2) adopts a reaction tower variable frequency motor (a), a reaction tower compressor pressure gauge (b) is provided on the reaction tower compressor outlet pipeline, and an instrument control interlock is provided between the reaction tower compressor pressure gauge (b) and the reaction tower variable frequency motor (a).

[0008] Preferably, an atmospheric tower pressure gauge (j) is provided at the top of the atmospheric tower (T3), an atmospheric tower condenser regulating valve (i) is provided on the pipeline from the gas phase outlet at the top of the atmospheric tower (T3) to the gas phase inlet of the atmospheric tower condenser (E3), and an instrument control interlock is provided between the atmospheric tower condenser regulating valve (i) and the atmospheric tower pressure gauge (j).

[0009] Preferably, an atmospheric tower compressor regulating valve (h) is provided on the pipeline from the top gas phase outlet of the atmospheric tower (T3) to the inlet pipeline of the atmospheric tower compressor (P4), the atmospheric tower compressor (P4) adopts an atmospheric tower variable frequency motor (f), an atmospheric tower compressor pressure gauge (g) is provided on the atmospheric tower compressor outlet pipeline, and an instrument control interlock is provided between the atmospheric tower compressor pressure gauge (g) and the atmospheric tower variable frequency motor (f).

[0010] Preferably, the outlet pipeline of the reaction tower compressor (P2) and the outlet pipeline of the atmospheric pressure tower compressor (P4) are directly connected to the feed port of the high-pressure tower (T2), and the high-pressure tower (T2) adopts a gas-phase feed method.

[0011] The advantages and beneficial effects of the utility model are as follows: the high-pressure tower adopts a gas-phase feeding method, which reduces the steam consumption of the high-pressure tower reboiler; the reaction tower and the atmospheric tower top extraction adopt a gas-phase method, which reduces the investment in equipment such as condensers and reduces the consumption of circulating water for condensation; the reaction tower compressor and the atmospheric tower compressor adopt a variable frequency motor, and the compressor inlet adopts a regulating valve to control the flow rate, thereby reducing the unit's power consumption when the device load is adjusted; at the same time, the compressor outlet pressure is adjusted by the variable frequency motor, so that the compressor outlet pressure is as low as possible while meeting the high-pressure tower feed, thereby preventing the product from being affected by high temperature caused by excessive compression ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of the utility model.

[0013] Figure symbols: T1 reaction tower, T2 high-pressure tower, T3 atmospheric pressure tower, E1 reaction tower condenser, V1 reaction tower reflux tank, P1 reaction tower reflux pump, P2 reaction tower compressor, E2 high-pressure tower reboiler, E3 atmospheric pressure tower condenser, V2 atmospheric pressure tower reflux tank, P3 atmospheric pressure tower reflux pump, P4 atmospheric pressure tower compressor, a reaction tower frequency conversion motor, b reaction tower compressor pressure gauge, c reaction tower condenser regulating valve, d reaction tower compressor regulating valve, e reaction tower pressure gauge, f atmospheric pressure tower frequency conversion motor, g atmospheric pressure tower compressor pressure gauge, h atmospheric pressure tower compressor regulating valve, i atmospheric pressure tower condenser regulating valve, j atmospheric pressure tower pressure gauge. DETAILED DESCRIPTION

[0014] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0015] Example 1, refer to the attached Figure 1 The utility model discloses a device for producing dimethyl carbonate, comprising a reaction tower (T1), a high-pressure tower (T2), a normal-pressure tower (T3), a reaction tower condenser (E1), a reaction tower reflux tank (V1), a reaction tower reflux pump (P1), a reaction tower compressor (P2), a high-pressure tower reboiler (E2), a normal-pressure tower condenser (E3), a normal-pressure tower reflux tank (V2), a normal-pressure tower reflux pump (P3), and a normal-pressure tower compressor (P4). The inlet of the reaction tower (T1) is connected to a raw material feed pipeline. The gas phase outlet at the top of the reaction tower (T1) is connected to the gas phase inlet of the reaction tower condenser (E1), the liquid phase outlet of the reaction tower condenser (E1) is connected to the liquid phase inlet of the reaction tower reflux tank (V1), the gas phase outlet of the reaction tower condenser (E1) is connected to the non-condensable gas system, the liquid phase outlet of the reaction tower reflux tank (V1) is connected to the inlet of the reaction tower reflux pump (P1), the outlet of the reaction tower reflux pump (P1) is connected to the reflux inlet of the reaction tower (T1), the gas phase outlet at the top of the reaction tower (T1) is connected to the inlet of the reaction tower compressor (P2), and the reaction The outlet of the compressor (P2) of the high-pressure tower is connected to the inlet of the high-pressure tower (T2), the liquid phase outlet of the bottom of the high-pressure tower (T2) is connected to the cold side inlet of the reboiler (E2) of the high-pressure tower, the cold side outlet of the reboiler (E2) of the high-pressure tower is connected to the bottom of the high-pressure tower (T2), the liquid phase outlet of the bottom of the high-pressure tower (T2) is connected to the crude dimethyl carbonate discharge pipeline, the top gas phase pipeline of the high-pressure tower (T2) is connected to the heat exchanger, the inlet of the atmospheric pressure tower (T3) is connected to the feed pipeline, and the top gas phase outlet of the atmospheric pressure tower (T3) is connected to the atmospheric pressure tower condenser (E3) The gas phase inlet is connected, the liquid phase outlet of the atmospheric tower condenser (E3) is connected to the liquid phase inlet of the atmospheric tower reflux tank (V2), the gas phase outlet of the atmospheric tower condenser (E3) is connected to the non-condensable gas system, the liquid phase outlet of the atmospheric tower reflux tank (V2) is connected to the inlet of the atmospheric tower reflux pump (P3), the outlet of the atmospheric tower reflux pump (P3) is connected to the reflux inlet of the atmospheric tower (T3), the gas phase outlet at the top of the atmospheric tower (T3) is connected to the inlet of the atmospheric tower compressor (P4), and the outlet of the atmospheric tower compressor (P4) is connected to the inlet of the high-pressure tower (T2).

[0016] A reaction tower pressure gauge (e) is provided at the top of the reaction tower (T1), a reaction tower condenser regulating valve (c) is provided on the pipeline from the gas phase outlet at the top of the reaction tower (T1) to the gas phase inlet of the reaction tower condenser (E1), and an instrument control interlock is provided between the reaction tower condenser regulating valve (c) and the reaction tower pressure gauge (e).

[0017] A reaction tower compressor regulating valve (d) is provided on the pipeline from the gas phase outlet at the top of the reaction tower (T1) to the inlet of the reaction tower compressor (P2); the reaction tower compressor (P2) adopts a reaction tower variable frequency motor (a); a reaction tower compressor pressure gauge (b) is provided on the reaction tower compressor outlet pipeline; and an instrument control interlock is provided between the reaction tower compressor pressure gauge (b) and the reaction tower variable frequency motor (a).

[0018] An atmospheric tower pressure gauge (j) is arranged at the top of the atmospheric tower (T3), an atmospheric tower condenser regulating valve (i) is arranged on the pipeline from the gas phase outlet at the top of the atmospheric tower (T3) to the gas phase inlet of the atmospheric tower condenser (E3), and an instrument control interlock is arranged between the atmospheric tower condenser regulating valve (i) and the atmospheric tower pressure gauge (j).

[0019] An atmospheric tower compressor regulating valve (h) is provided on the pipeline from the top gas phase outlet of the atmospheric tower (T3) to the inlet pipeline of the atmospheric tower compressor (P4); the atmospheric tower compressor (P4) adopts an atmospheric tower variable frequency motor (f); an atmospheric tower compressor pressure gauge (g) is provided on the atmospheric tower compressor outlet pipeline; and an instrument control interlock is provided between the atmospheric tower compressor pressure gauge (g) and the atmospheric tower variable frequency motor (f).

[0020] The outlet pipeline of the reaction tower compressor (P2) and the outlet pipeline of the atmospheric pressure tower compressor (P4) are directly connected to the feed port of the high-pressure tower (T2), and the high-pressure tower (T2) adopts a gas phase feed method.

[0021] When the utility model is used, a mixture of catalyst, methanol and propylene carbonate / ethylene carbonate enters a reaction tower (T1) for synthesis reaction and distillation separation. A portion of the gaseous methanol and dimethyl carbonate mixture obtained at the top of the reaction tower enters a reaction tower condenser (E1) for condensation and returns to the reaction tower as reflux. The required condensation reflux amount is adjusted by a reaction tower condenser regulating valve (c) to control the tower pressure to be too high. A portion of the mixture enters a high-pressure tower (T2) in the form of a gas phase for distillation after the flow is adjusted by a reaction tower compressor regulating valve (d). The outlet pressure of the reaction tower compressor is adjusted by a reaction tower variable frequency motor (a). The reaction tower kettle produces crude propylene glycol / ethylene glycol. The high-pressure tower reboiler (E2) is heated by steam, and the gas phase at the top of the high-pressure tower is condensed in other heat exchangers, and the tower kettle produces crude dimethyl carbonate. A portion of the gaseous methanol and dimethyl carbonate mixture at the top of the atmospheric tower (T3) enters the atmospheric tower condenser (E3) for condensation and then returns to the atmospheric tower as reflux. The atmospheric tower condenser regulating valve (i) adjusts the required reflux amount of condensation to control the tower pressure being too high; a portion of the mixture enters the high-pressure tower (T2) in the form of a gas phase for distillation after being pressurized by the atmospheric tower compressor (P4) after the flow is adjusted by the atmospheric tower compressor regulating valve (h). The atmospheric tower compressor outlet pressure is adjusted by the atmospheric tower variable frequency motor (f). The methanol extracted from the atmospheric tower kettle is recycled.

[0022] When the technical scheme of this embodiment is carried out, the original production device is transformed according to the content of this utility model when the annual output of 70,000 tons of dimethyl carbonate production device is tested. The device operation test results after the transformation are as follows, which show that the quality and output of the dimethyl carbonate product produced after the transformation meet the requirements, the consumption of steam and circulating water is greatly reduced, the consumption of standard oil per ton of product is reduced by 44.4%, the production cost is reduced by 44.3%, the production energy consumption and production cost are significantly reduced, and the expected effect is achieved.

[0023]

[0024] The above embodiment is only one implementation form of the device for producing dimethyl carbonate provided by the utility model. Other variations of the scheme provided by the utility model, increasing or reducing the components therein, or applying the utility model to other technical fields close to the utility model, all belong to the protection scope of the utility model.

Claims

1. A device for the production of dimethyl carbonate, characterized in that: The invention comprises a reaction tower (T1), a high-pressure tower (T2), a normal-pressure tower (T3), a reaction tower condenser (E1), a reaction tower reflux tank (V1), a reaction tower reflux pump (P1), a reaction tower compressor (P2), a high-pressure tower reboiler (E2), a normal-pressure tower condenser (E3), a normal-pressure tower reflux tank (V2), a normal-pressure tower reflux pump (P3), and a normal-pressure tower compressor (P4). The inlet of the reaction tower (T1) is connected to a raw material feed pipeline, and the gas phase outlet at the top of the reaction tower (T1) is connected to the reaction tower condenser. The gas phase inlet of the condenser (E1) is connected, the liquid phase outlet of the reaction tower condenser (E1) is connected to the liquid phase inlet of the reaction tower reflux tank (V1), the gas phase outlet of the reaction tower condenser (E1) is connected to the non-condensable gas system, the liquid phase outlet of the reaction tower reflux tank (V1) is connected to the inlet of the reaction tower reflux pump (P1), the outlet of the reaction tower reflux pump (P1) is connected to the reflux inlet of the reaction tower (T1), the gas phase outlet at the top of the reaction tower (T1) is connected to the inlet of the reaction tower compressor (P2), and the outlet of the reaction tower compressor (P2) is connected to The inlet of the high-pressure tower (T2) is connected, the liquid phase outlet of the tower bottom of the high-pressure tower (T2) is connected to the cold side inlet of the high-pressure tower reboiler (E2), the cold side outlet of the high-pressure tower reboiler (E2) is connected to the tower bottom of the high-pressure tower (T2), the liquid phase outlet of the tower bottom of the high-pressure tower (T2) is connected to the crude dimethyl carbonate discharge pipeline, the gas phase pipeline at the top of the high-pressure tower (T2) is connected to the heat exchanger, the inlet of the atmospheric pressure tower (T3) is connected to the feed pipeline, and the gas phase outlet at the top of the atmospheric pressure tower (T3) is connected to the gas phase inlet of the atmospheric pressure tower condenser (E3) The liquid phase outlet of the atmospheric tower condenser (E3) is connected to the liquid phase inlet of the atmospheric tower reflux tank (V2), the gas phase outlet of the atmospheric tower condenser (E3) is connected to the non-condensable gas system, the liquid phase outlet of the atmospheric tower reflux tank (V2) is connected to the inlet of the atmospheric tower reflux pump (P3), the outlet of the atmospheric tower reflux pump (P3) is connected to the reflux inlet of the atmospheric tower (T3), the gas phase outlet at the top of the atmospheric tower (T3) is connected to the inlet of the atmospheric tower compressor (P4), and the outlet of the atmospheric tower compressor (P4) is connected to the inlet of the high-pressure tower (T2).

2. A device for producing dimethyl carbonate according to claim 1, characterized in that: A reaction tower pressure gauge (e) is arranged at the top of the reaction tower (T1), a reaction tower condenser regulating valve (c) is arranged on the pipeline from the gas phase outlet at the top of the reaction tower (T1) to the gas phase inlet of the reaction tower condenser (E1), and an instrument control interlock is arranged between the reaction tower condenser regulating valve (c) and the reaction tower pressure gauge (e).

3. A device for producing dimethyl carbonate according to claim 1, characterized in that: A reaction tower compressor regulating valve (d) is provided on the pipeline from the gas phase outlet at the top of the reaction tower (T1) to the inlet of the reaction tower compressor (P2); the reaction tower compressor (P2) adopts a reaction tower variable frequency motor (a); a reaction tower compressor pressure gauge (b) is provided on the reaction tower compressor outlet pipeline; and an instrument control interlock is provided between the reaction tower compressor pressure gauge (b) and the reaction tower variable frequency motor (a).

4. A device for producing dimethyl carbonate according to claim 1, characterized in that: An atmospheric tower pressure gauge (j) is arranged at the top of the atmospheric tower (T3), an atmospheric tower condenser regulating valve (i) is arranged on the pipeline from the gas phase outlet at the top of the atmospheric tower (T3) to the gas phase inlet of the atmospheric tower condenser (E3), and an instrument control interlock is arranged between the atmospheric tower condenser regulating valve (i) and the atmospheric tower pressure gauge (j).

5. A device for producing dimethyl carbonate according to claim 1, characterized in that: An atmospheric tower compressor regulating valve (h) is provided on the pipeline from the top gas phase outlet of the atmospheric tower (T3) to the inlet pipeline of the atmospheric tower compressor (P4); the atmospheric tower compressor (P4) adopts an atmospheric tower variable frequency motor (f); an atmospheric tower compressor pressure gauge (g) is provided on the atmospheric tower compressor outlet pipeline; and an instrument control interlock is provided between the atmospheric tower compressor pressure gauge (g) and the atmospheric tower variable frequency motor (f).

6. A device for producing dimethyl carbonate according to claim 1, characterized in that: The outlet pipeline of the reaction tower compressor (P2) and the outlet pipeline of the atmospheric pressure tower compressor (P4) are directly connected to the feed port of the high-pressure tower (T2), and the high-pressure tower (T2) adopts a gas phase feed method.

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