CN115350679B - Device and method for preparing dimethyl carbonate by high-speed jet impact tubular reactor - Google Patents

Abstract

The invention relates to a device and a method for preparing dimethyl carbonate by a high-speed jet impact tubular reactor, wherein the device comprises a material mixing tank, a first high-speed jet impact tubular reactor, a vapor-liquid separation tank, a second high-speed jet impact tubular reactor, a curing tank, a light component separation tower system, a methanol rectifying tower system and a dimethyl carbonate rectifying tower system which are sequentially communicated; meanwhile, the material distribution tank is communicated with the glycol rectifying tower system, the methanol rectifying tower system is respectively communicated with the first high-speed jet impact tubular reactor and the second high-speed jet impact tubular reactor, the vapor-liquid separation tank is communicated with the light component separating tower system, and the light component separating tower system is communicated with the glycol rectifying tower system. The device and the method solve the problems of low heat and mass transfer efficiency, long reaction period, high energy consumption, low reaction rate, low product yield and the like of the traditional equipment and process for preparing the dimethyl carbonate.

Description

Device and method for preparing dimethyl carbonate by high-speed jet impact tubular reactor

Technical Field

The invention belongs to the technical field of chemical industry, and particularly relates to a device and a method for preparing dimethyl carbonate by using a high-speed jet impact tubular reactor.

Background technique

The production methods of dimethyl carbonate are generally phosgene method, methanol oxidation carbonylation method and ester exchange method. Since the phosgene method uses highly toxic phosgene as the main raw material, it has been basically eliminated, and the other two methods have become the main methods for synthesizing DMC. The technology of synthesizing DMC by ester exchange method with co-production of ethylene glycol has developed rapidly in recent years. The preparation process of dimethyl carbonate generally adopts a kettle reactor and mechanical stirring. The disadvantages of this preparation equipment are low heat and mass transfer efficiency, long reaction cycle, high energy consumption, and increased energy consumption leads to rising costs, which is not conducive to industrial production.

The art is eager to find a low-energy consumption, environmentally friendly process and equipment for preparing dimethyl carbonate to overcome the above technical problems.

Summary of the invention

The invention provides a device and a method for preparing dimethyl carbonate by using a high-speed jet impact tubular reactor, and aims to solve the problems of low heat and mass transfer efficiency, long reaction cycle, high energy consumption, low reaction rate and product yield in the existing equipment and process for preparing dimethyl carbonate.

To achieve the above object, the present invention adopts the following technical solutions:

The invention discloses a device for preparing dimethyl carbonate by using a high-speed jet impingement tubular reactor, which comprises a batching tank, a first high-speed jet impingement tubular reactor, a vapor-liquid separation tank, a second high-speed jet impingement tubular reactor, a maturation tank, a light component separation tower system, a methanol distillation tower system and a dimethyl carbonate distillation tower system which are connected in sequence; at the same time, the batching tank is connected to the ethylene glycol distillation tower system, the methanol distillation tower system is connected to the first high-speed jet impingement tubular reactor and the second high-speed jet impingement tubular reactor respectively, the vapor-liquid separation tank is connected to the light component separation tower system, and the light component separation tower system is connected to the ethylene glycol distillation tower system.

Furthermore, the batching tank, the vapor-liquid separation tank and the maturation tank have the same structure, and are all tank structures with a heat medium arranged on the outer circumference and a mechanical agitator arranged inside; the liquid inlet on the top of the batching tank is connected to the outlet end of the bottom pump of the ethylene glycol distillation tower of the ethylene glycol distillation tower system; the liquid outlet at the bottom of the batching tank is connected to the outlets of the two first Laval nozzles of the first high-speed jet impact tubular reactor through the first power fluid pump;

The inlet end of the upper end of the vapor-liquid separation tank is connected to the outlet end of the first tubular reactor of the first high-speed jet impact tubular reactor, the vapor outlet end of the upper end of the vapor-liquid separation tank is connected to the vapor inlet end of the light component separation tower system through the separation tank condenser, and the outlet end of the bottom end of the vapor-liquid separation tank is connected to the orifices of the two second Laval nozzles of the second high-speed jet impact tubular reactor through the second power fluid pump;

The top liquid inlet of the maturation tank is connected to the outlet end of the second tubular reactor of the second high-speed jet impact tubular reactor, and the upper overflow port of the maturation tank is connected to the top liquid inlet of the light component separation tower kettle of the light component separation tower system.

Further, the first high-speed jet impact tubular reactor has the same structure as the second high-speed jet impact tubular reactor, and the first high-speed jet impact tubular reactor includes a first Laval nozzle, a first mixing chamber, a first high-speed jet impact chamber, a first tubular reactor and a first heater; the first Laval nozzle, the first mixing chamber, the first high-speed jet impact chamber and the first tubular reactor are all arranged inside the first heater, the two first Laval nozzles are arranged opposite to each other and connected, and the cavity formed at the middle connecting part is the first mixing chamber, the first high-speed jet impact chamber is connected in the vertical direction of the middle of the first mixing chamber, the first high-speed jet impact chamber is connected to one end of the first tubular reactor, and the other end of the first tubular reactor is connected to the liquid inlet at the top of the vapor-liquid separation tank, and steam inlets are opened at the nozzles of the two first Laval nozzles, and the steam inlets are connected to the outlet end of the methanol vaporizer of the methanol distillation tower system;

The second high-speed jet impact tubular reactor includes a second Laval nozzle, a second mixing chamber, a second high-speed jet impact chamber, a second tubular reactor, and a second heater; the second Laval nozzle, the second mixing chamber, the second high-speed jet impact chamber, and the second tubular reactor are all arranged inside the second heater, the two second Laval nozzles are arranged opposite to each other and connected, the cavity formed by the middle connecting part is the second mixing chamber, the second high-speed jet impact chamber is connected in the vertical direction of the middle of the second mixing chamber, the second high-speed jet impact chamber is connected to one end of the second tubular reactor, and the other end of the second tubular reactor is connected to the liquid inlet at the top of the maturation tank; the nozzles of the two second Laval nozzles are connected to the liquid outlet at the bottom of the vapor-liquid separation tank through the second power fluid pump, and the nozzles of the two second Laval nozzles are provided with steam inlets, which are connected to the outlet end of the methanol vaporizer of the methanol distillation tower system. Further, the length-to-diameter ratio of the first tubular reactor is 1000, and the length-to-diameter ratio of the second tubular reactor is 1000.

Furthermore, the light component separation tower system includes a light component separation tower kettle, a light component white steel structured packing tower, a light component condenser, a light component receiving tank, a light component liquid pump and a light component separation tower bottom pump; the light component separation tower kettle is a structure with a heat medium arranged on the outer circumference, the liquid inlet at the top of the light component separation tower kettle is connected with the upper overflow port of the maturation tank, the liquid outlet at the bottom of the light component separation tower kettle is connected with the liquid inlet of the light component separation tower bottom pump, the outlet of the light component separation tower bottom pump is connected with the liquid reflux inlet of the light component separation tower kettle, and the outlet end of the light component separation tower bottom pump is connected to the second The liquid inlet of the alcohol distillation tower system; the upper end of the light component separation tower kettle is connected to the light component white steel structured packing tower and is integrally arranged, the steam inlet end of the light component white steel structured packing tower is connected to the outlet end of the separation tank condenser, the steam outlet end of the light component white steel structured packing tower is connected to the inlet end of the light component condenser, the outlet end of the light component condenser is connected to the inlet end of the light component receiving tank, the outlet end of the light component receiving tank is connected to the outlet end of the light component liquid pump, the outlet end of the light component liquid pump is connected to the upper reflux liquid inlet of the light component white steel structured packing tower, and the outlet end of the light component liquid pump is also connected to the liquid inlet of the methanol distillation tower system.

Furthermore, the methanol distillation tower system includes a methanol distillation tower reboiler, a methanol distillation tower white steel structured packing tower, a methanol distillation tower condenser, a methanol distillation tower azeotropic liquid receiving tank, a methanol distillation tower azeotropic liquid pump, a methanol vaporizer and a methanol distillation tower bottom pump; the middle liquid inlet of the methanol distillation tower system is connected to the outlet end of the light component liquid pump of the light component separation tower system and is also connected to the outlet end of the dimethyl carbonate distillation tower azeotropic liquid pump of the dimethyl carbonate distillation tower system; the steam outlet at the top of the methanol distillation tower white steel structured packing tower is connected to the inlet end of the methanol distillation tower condenser, the outlet end of the methanol distillation tower condenser is connected to the inlet end of the top of the methanol distillation tower azeotropic liquid receiving tank, and the outlet end of the bottom of the methanol distillation tower azeotropic liquid receiving tank is connected to the inlet end of the methanol distillation tower azeotropic liquid pump The outlet end of the methanol distillation tower azeotropic liquid pump is connected to the upper reflux liquid inlet of the white steel structured packing tower of the methanol distillation tower and is also connected to the liquid inlet in the middle of the dimethyl carbonate distillation tower system; the bottom liquid outlet of the white steel structured packing tower of the methanol distillation tower is connected to the inlet end of the bottom pump of the methanol distillation tower, and the outlet end of the bottom pump of the methanol distillation tower is connected to the inlet end of the reboiler of the methanol distillation tower. The reboiler of the methanol distillation tower is a structure provided with a heat medium, and the outlet end of the reboiler of the methanol distillation tower is connected to the reboiled liquid reflux port of the white steel structured packing tower of the methanol distillation tower; the outlet end of the bottom pump of the methanol distillation tower is also connected to the inlet end of the methanol vaporizer, and the inlet end of the methanol vaporizer is also connected to the inlet end of fresh methanol, and the outlet end of the methanol vaporizer is respectively connected to the steam inlets of the first Laval nozzle and the second Laval nozzle.

Furthermore, the dimethyl carbonate distillation tower system comprises a dimethyl carbonate distillation tower reboiler, a dimethyl carbonate distillation tower white steel structured packing tower, a dimethyl carbonate distillation tower condenser, a dimethyl carbonate distillation tower azeotropic liquid receiving tank, a dimethyl carbonate distillation tower azeotropic liquid pump, a dimethyl carbonate storage tank and a dimethyl carbonate distillation tower bottom pump; the liquid inlet in the middle of the dimethyl carbonate distillation tower white steel structured packing tower is connected to the outlet end of the azeotropic liquid pump of the methanol distillation tower; the steam outlet at the top of the white steel structured packing tower of the dimethyl carbonate distillation tower is connected to the inlet end of the dimethyl carbonate distillation tower condenser, the outlet end of the dimethyl carbonate distillation tower condenser is connected to the inlet end of the top of the dimethyl carbonate distillation tower azeotropic liquid receiving tank, and the outlet end at the bottom of the dimethyl carbonate distillation tower azeotropic liquid receiving tank is connected to the dimethyl carbonate distillation tower azeotropic liquid receiving tank. The inlet end of the azeotropic liquid pump of the ester distillation tower and the outlet end of the azeotropic liquid pump of the dimethyl carbonate distillation tower are connected to the reflux liquid inlet of the upper part of the white steel structured packing tower of the dimethyl carbonate distillation tower, and the outlet end of the azeotropic liquid pump of the dimethyl carbonate distillation tower is also connected to the liquid inlet in the middle of the methanol distillation tower system; the bottom liquid outlet of the white steel structured packing tower of the dimethyl carbonate distillation tower is connected to the inlet end of the bottom pump of the dimethyl carbonate distillation tower, and the outlet end of the bottom pump of the dimethyl carbonate distillation tower is connected to the inlet end of the reboiler of the dimethyl carbonate distillation tower, the reboiler of the dimethyl carbonate distillation tower is a structure provided with a heat medium, and the outlet end of the reboiler of the dimethyl carbonate distillation tower is connected to the reboiled liquid reflux port of the white steel structured packing tower of the dimethyl carbonate distillation tower; the outlet end of the bottom pump of the dimethyl carbonate distillation tower is also connected to the top inlet end of the dimethyl carbonate storage tank.

Furthermore, the ethylene glycol distillation tower system includes an ethylene glycol distillation tower reboiler, an ethylene glycol distillation tower white steel structured packing tower, an ethylene glycol distillation tower condenser, an ethylene glycol receiving tank, an ethylene glycol pump, an ethylene glycol storage tank and an ethylene glycol distillation tower bottom pump; the middle liquid inlet of the ethylene glycol distillation tower system is connected to the outlet end of the light component separation tower bottom pump; the steam outlet at the top of the ethylene glycol distillation tower white steel structured packing tower is connected to the inlet end of the ethylene glycol distillation tower condenser, the outlet end of the ethylene glycol distillation tower condenser is connected to the inlet end of the top of the ethylene glycol receiving tank, and the outlet end at the bottom of the ethylene glycol receiving tank is connected to the inlet end of the ethylene glycol pump. The outlet end of the ethylene glycol pump is connected to the reflux liquid inlet of the upper part of the white steel structured packing tower of the ethylene glycol distillation tower, and the outlet end of the ethylene glycol pump is also connected to the top inlet end of the ethylene glycol storage tank; the bottom liquid outlet of the white steel structured packing tower of the ethylene glycol distillation tower is connected to the inlet end of the bottom pump of the ethylene glycol distillation tower, and the outlet end of the bottom pump of the ethylene glycol distillation tower is connected to the inlet end of the reboiler of the ethylene glycol distillation tower. The reboiler of the ethylene glycol distillation tower is a structure provided with a heat medium, and the outlet end of the reboiler of the ethylene glycol distillation tower is connected to the reboiled liquid reflux port of the white steel structured packing tower of the ethylene glycol distillation tower; the outlet end of the bottom pump of the ethylene glycol distillation tower is also connected to the top inlet end of the batching tank.

A method for preparing dimethyl carbonate by using a high-speed jet impinging tubular reactor comprises the following steps:

Step 1. The raw material ethylene carbonate and the catalyst are put into a batching tank and stirred and mixed to obtain a mixed liquid, wherein the amount of the catalyst is 0.15% to 0.25% of the mass of the ethylene carbonate; the mixed liquid reaches the reaction temperature under the heating of the heat medium, and continuously enters the first high-speed jet impact tubular reactor through the first power fluid pump;

Step 2. The mixed liquid in the batching tank is pumped into two opposing first Laval nozzles through a power fluid pump, and methanol vapor is sucked in at the same time. The molar ratio of methanol to ethylene carbonate is 4 to 4.4:1. The two high-speed jets ejected from the first Laval tube collide with each other in the high-speed jet impact chamber, and then enter the first tubular reactor for ester exchange reaction to obtain dimethyl carbonate vapor and ester exchange liquid. The methanol vapor, dimethyl carbonate vapor generated by the reaction, and the ester exchange liquid continuously enter the vapor-liquid separation tank;

Step 3. The vapor-liquid separation tank separates the methanol vapor, the dimethyl carbonate vapor generated by the reaction and the transesterification liquid, and the separated methanol vapor and the dimethyl carbonate vapor generated by the reaction enter the light component separation tower system; the transesterification liquid with the separated light component continuously enters the second high-speed jet impact tubular reactor through the second power fluid pump;

Step 4. The transesterification liquid in the vapor-liquid separation tank is pumped into two opposing second Laval nozzles through a second power fluid pump, and methanol vapor is sucked in at the same time. The amount of methanol added is the same as that in step 2. The two high-speed jets ejected from the second Laval tubes collide with each other in the high-speed jet impact chamber, and then enter the second tubular reactor for transesterification reaction. The methanol vapor from the second high-speed jet impact tubular reactor, the dimethyl carbonate vapor generated by the reaction, and the transesterification liquid continuously enter the maturation tank;

Step 5. The ester exchange liquid continues to undergo supplementary ester exchange reaction in the aging tank; the aging liquid overflowing from the aging tank enters the light component separation tower system;

Step 6. The methanol vapor from the vapor-liquid separation tank, the dimethyl carbonate vapor generated by the reaction, and the mature liquid from the mature tank continuously enter the light component separation tower system, the light component vapor separated by the light component separation tower system is condensed by the condenser and enters the light component liquid receiving tank, part of the light component liquid separated by the light component separation tower system is used as the reflux of the light component separation tower system, and part of it enters the methanol distillation tower system; the bottom liquid of the light component separation tower system continuously enters the ethylene glycol distillation tower system through the bottom pump of the separation tower;

Step 7. The light component liquid from the light component separation tower system and the azeotropic liquid from the azeotropic liquid receiving tank of the dimethyl carbonate distillation tower continuously enter the methanol distillation tower system, the azeotropic vapor separated from the top of the methanol distillation tower system is condensed by the methanol distillation tower condenser and enters the azeotropic liquid receiving tank to obtain the azeotropic liquid, part of which is used as the reflux of the methanol distillation tower system, and part of which enters the dimethyl carbonate distillation tower system; the bottom liquid of the methanol distillation tower system enters the methanol vaporizer through the bottom pump of the methanol distillation tower, and the vaporized methanol is continuously used for the transesterification reaction;

Step 8. The azeotropic liquid from the azeotropic liquid receiving tank of the methanol distillation tower system continuously enters the dimethyl carbonate distillation tower system, the azeotropic product vapor separated from the top of the dimethyl carbonate distillation tower system is condensed by the dimethyl carbonate distillation tower condenser and enters the azeotropic liquid receiving tank of the dimethyl carbonate distillation tower to obtain the azeotropic liquid, part of which is used as reflux of the dimethyl carbonate distillation tower system, and part of which is returned to the methanol distillation tower system as feed; the bottom liquid of the dimethyl carbonate distillation tower system enters the dimethyl carbonate storage tank through the bottom pump of the dimethyl carbonate distillation tower;

Step 9. The bottom liquid from the light component separation tower system continuously enters the ethylene glycol distillation tower system, and the ethylene glycol vapor separated from the top of the ethylene glycol distillation tower system is condensed by the ethylene glycol distillation tower condenser and enters the ethylene glycol receiving tank to obtain ethylene glycol, part of which is used as reflux of the ethylene glycol distillation tower system, and part of which is fed into the ethylene glycol storage tank; the bottom liquid of the ethylene glycol distillation tower system is partially pumped into the ethylene glycol distillation tower reboiler for heating and then returned to the ethylene glycol distillation tower system, and part of which is continuously entered into the batching tank as a recovered catalyst.

Furthermore, in step 1, the temperature in the batching tank is 70°C to 75°C, the pressure is normal pressure, and the residence time of the material is 0.5h to 0.75h;

In step 2, the temperature in the first high-speed jet impact tubular reactor is 80° C. to 85° C., and the pressure is 0.2 MPa to 0.25 MPa;

In step 3, the temperature in the vapor-liquid separation tank is 70°C to 75°C, the pressure is normal pressure, and the residence time of the material is 0.5h to 0.75h;

In step 4, the temperature in the second high-speed jet impact tubular reactor is 80° C. to 85° C., and the pressure is 0.2 MPa to 0.25 MPa:

In step 5, the temperature in the aging tank is 80°C to 85°C, the pressure is 0.2MPa to 0.25MPa, and the residence time of the material is 1.5h to 2h;

In step 6, the kettle temperature of the light component separation tower system is 75°C to 78°C, the tower top temperature is 64°C to 66°C, the reflux ratio is 3 to 4, and the pressure is normal pressure;

In step 7, the bottom temperature of the methanol distillation tower system is 70° C., the bottom pressure is 0.13 MPa; the top temperature is 64° C., the top pressure is normal pressure, and the reflux ratio is 2;

In step 8, the bottom temperature of the dimethyl carbonate distillation tower system is 183° C., the bottom pressure is 1.33 MPa; the top temperature is 147° C., the top pressure is 1.30 MPa, and the reflux ratio is 1.2;

In step 9, the top temperature of the ethylene glycol distillation tower system is 150° C., and the top pressure is 0.02 MPa; the bottom temperature is 178° C., and the reflux ratio is 1.5.

Compared with the prior art, the device and method for preparing dimethyl carbonate by using a high-speed jet impingement tubular reactor of the present invention have the following beneficial effects:

1. The high-speed jet impact tubular reactor is used for transesterification reaction. Two heterogeneous fluids flow toward each other at high speed, forming a highly turbulent impact zone through impact. The impact flow effectively improves the mixing and mass transfer effect in the reactor, and increases the reaction rate and product yield.

2. Shortened the reaction time, saved energy, improved production efficiency, green and environmentally friendly;

3. This device produces ethylene glycol as a by-product while producing dimethyl carbonate, which improves the economic benefits of the device;

4. The yield of dimethyl carbonate is greater than 95%, and the quality of dimethyl carbonate is better than the national industrial standard; the process of the present invention is mature, the equipment is advanced, the operation is continuous, and the degree of automation is high.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a device for preparing dimethyl carbonate using a high-speed jet impingement tubular reactor according to the present invention;

Figure numerals: 1, batching tank, 1-1, mechanical stirrer, 1-2, first power fluid pump; 2, first high-speed jet impact tubular reactor, 2-1, first Laval nozzle, 2-2, mixing chamber, 2-3, first high-speed jet impact chamber, 2-4, first tubular reactor, 2-5, first heater; 3, vapor-liquid separation tank, 3-1, separation tank mechanical stirrer, 3-2, separation tank condenser, 3-3, second power fluid pump; 4, second high-speed jet impact tubular reactor reactor, 4-1, second Laval nozzle, 4-2, mixing chamber, 4-3, second high-speed jet impact chamber, 4-4, second tubular reactor, 4-5, second heater; 5, maturation tank, 5-1, maturation tank mechanical agitator; 6, light component separation tower, 6-1, light component separation tower kettle, 6-2, light component white steel structured packing, 6-3, light component condenser, 6-4, light component receiving tank, 6-5, light component liquid pump, 6-6, light component separation tower bottom pump; 7, Methanol distillation tower, 7-1, methanol distillation tower reboiler, 7-2, methanol distillation tower white steel structured packing, 7-3, methanol distillation tower condenser, 7-4, methanol distillation tower azeotropic liquid receiving tank, 7-5, methanol distillation tower azeotropic liquid pump, 7-6, methanol vaporizer, 7-7, methanol distillation tower bottom pump; 8, dimethyl carbonate distillation tower, 8-1, dimethyl carbonate distillation tower reboiler, 8-2, dimethyl carbonate distillation tower white steel structured packing, 8-3, dimethyl carbonate distillation tower condenser , 8-4, azeotropic liquid receiving tank for dimethyl carbonate distillation tower, 8-5, azeotropic liquid pump for dimethyl carbonate distillation tower, 8-6, dimethyl carbonate storage tank, 8-7, bottom pump for dimethyl carbonate distillation tower; 9, ethylene glycol distillation tower, 9-1, reboiler for ethylene glycol distillation tower, 9-2, white steel structured packing for ethylene glycol distillation tower, 9-3, condenser for ethylene glycol distillation tower, 9-4, ethylene glycol receiving tank, 9-5, ethylene glycol pump, 9-6, ethylene glycol storage tank, 9-7, bottom pump for ethylene glycol distillation tower.

Detailed ways

In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

In view of engineering problems and market demands, in order to overcome the problems existing in the prior art, the present invention provides a method with mature process, continuous operation, high degree of automation, advanced reactor technology, high reaction efficiency, energy saving and environmental friendliness; an advanced high-speed jet impact tubular reactor is adopted for ester exchange reaction, and since the mixed liquid is ejected at high speed through the Laval tube, a negative pressure zone will be generated at the gas suction port, causing the gas to be sucked in, and rapidly expand in the negative pressure zone and be beaten into tiny bubbles by the power fluid, and enter the mixing chamber; at this time, in the mixing chamber, the gas and liquid are fully mixed in the mixing chamber, and are accelerated to be discharged due to energy exchange, and the speed can reach the speed of sound, and the potential energy of the mixed liquid is increased to the maximum, which is more The mass transfer and heat transfer effects are enhanced; two fluids flow towards each other at high speed, and a highly turbulent collision zone is formed through collision, which greatly enhances the process heat and mass transfer; the strong microscopic mixing and pressure fluctuation characteristics of the impact flow can make the chemical reaction proceed rapidly and instantly produce effective and uniform supersaturation; and because the chaotic flow state rapidly reduces the mixing scale, vortices of different scales and folding collisions with each other enhance the turbulence intensity and energy diffusion, prompting molecules to reach more effective high-energy level collisions when chemical reactions occur. The impact flow enhances heat and mass transfer, improves the reaction rate and product yield, and the quality of the prepared dimethyl carbonate is higher than the industrial grade national standard, which improves the reaction rate and product yield.

As shown in Figure 1, the device for preparing dimethyl carbonate by using a high-speed jet impinging tubular reactor comprises a batching tank 1, a first high-speed jet impinging tubular reactor 2, a vapor-liquid separation tank 3, a second high-speed jet impinging tubular reactor 4, a maturation tank 5, a light component separation tower system 6, a methanol distillation tower system 7 and a dimethyl carbonate distillation tower system 8 which are connected in sequence; at the same time, the batching tank 1 is also connected to the ethylene glycol distillation tower system 9, the methanol distillation tower system 7 is also connected to the first high-speed jet impinging tubular reactor 2 and the second high-speed jet impinging tubular reactor 4, respectively, the vapor-liquid separation tank 3 is also connected to the light component separation tower system 6, and the light component separation tower system 6 is also connected to the ethylene glycol distillation tower system 9.

The batching tank 1 is a tank structure with a heat medium arranged on the outer circumference and a mechanical stirrer 1-1 arranged inside. The top of the batching tank 1 is provided with catalyst and ethylene carbonate liquid inlets, and the top liquid inlet of the batching tank 1 is connected to the outlet end of the ethylene glycol distillation tower bottom pump 9-7 of the ethylene glycol distillation tower system 9; the bottom liquid outlet of the batching tank 1 is connected to the inlet end of the first power fluid pump 1-2, and the outlet end of the first power fluid pump 1-2 is connected to the liquid inlet end of the first Laval nozzle 2-1 of the first high-speed jet impact tubular reactor 2; the batching tank 1 is used for batching ethylene carbonate and catalyst, and at the same time, ethylene carbonate and catalyst are evenly mixed under the action of stirring; the mixed liquid reaches the reaction temperature under the heating of the heat medium, and enters the first high-speed jet impact tubular reactor 2 through the power fluid pump 1-2.

The first high-speed jet impact tubular reactor 2 includes a first Laval nozzle 2-1, a first mixing chamber 2-2, a first high-speed jet impact chamber 2-3, a first tubular reactor 2-4 and a first heater 2-5; the first Laval nozzle 2-1, the first mixing chamber 2-2, the first high-speed jet impact chamber 2-3 and the first tubular reactor 2-4 are all arranged inside the first heater 2-5, the two first Laval nozzles 2-1 are arranged opposite to each other and connected, and the cavity formed at the middle connecting part is the first mixing chamber 2-2, the first high-speed jet impact chamber 2-3 is connected in the vertical direction of the middle of the first mixing chamber 2-2, the first high-speed jet impact chamber 2-3 is connected to one end of the first tubular reactor 2-4, and the other end of the first tubular reactor 2-4 is connected to the liquid inlet at the top of the vapor-liquid separation tank 3, the first tubular reactor 2-4 is a tube with a length-to-diameter ratio greater than 1000, which can be Φ75mm or Φ100mm, and can be set to a reciprocating type or a spring type.

Steam inlets are provided at the orifices of the two first Laval nozzles 2 - 1 , and the steam inlets are connected to the outlet end of the methanol vaporizer 7 - 6 of the methanol distillation tower system 7 . The first high-speed jet impact tubular reactor 2 is used for ester exchange reaction; the two opposing first Laval nozzles 2-1 are connected to the batching tank 1 through the first power fluid pump 1-2, and are connected to the outlet end of the methanol vaporizer 7-6 of the methanol distillation tower system 7, the mixed liquid in the batching tank 1 is pumped into the two opposing first Laval nozzles 2-1 through the first power fluid pump 1-2, and the air inlets of the two opposing first Laval nozzles 2-1 simultaneously inhale the methanol vapor vaporized at the outlet end of the methanol vaporizer 7-6 of the methanol distillation tower system 7, and the two high-speed jets ejected from the first Laval nozzles 2-1 (the mixed liquid in the batching tank 1 and the methanol vapor of the methanol distillation tower system 7) collide with each other in the high-speed jet impact chamber 2-3 through the first mixing chamber 2-2, and then enter the first tubular reactor 2-4 for ester exchange reaction, and the ester exchange liquid continuously enters the vapor-liquid separation tank 3.

Specifically, since the raw material mixed liquid in the batching tank 1 is ejected at high speed through the first Laval nozzle 2-1, a negative pressure zone will be generated at the steam inlet of the first Laval nozzle 2-1, causing the methanol vapor of the methanol distillation tower system 7 to be sucked in, and rapidly expand in its negative pressure zone and be beaten into tiny bubbles by the power fluid, and enter the first mixing chamber 2-2 of the first Laval nozzle 2-1; at this time, in the first mixing chamber 2-2, the methanol vapor and the mixed liquid are fully mixed, and are accelerated to be discharged due to energy exchange, and the speed can reach the speed of sound, and then the potential energy of the mixed liquid is increased to the maximum through the first mixing chamber 2-2 of the first Laval nozzle 2-1, which further enhances the mass transfer. , heat transfer effect; the two fluids from the first Laval nozzle 2-1 flow towards each other at high speed, forming a highly turbulent impact zone through collision, which greatly enhances the process heat and mass transfer; the strong micro-mixing and pressure fluctuation characteristics of the impact flow can make the chemical reaction proceed rapidly and instantly produce effective and uniform supersaturation; and due to the chaotic flow state, the mixing scale is rapidly reduced, and the vortices of different scales and the folding collisions with each other enhance the turbulence intensity and energy diffusion, which promotes the molecules to reach more effective high-energy level collisions when chemical reactions occur. The impact flow effectively improves the mixing and mass transfer effects in the reactor, and increases the reaction rate and product yield.

The vapor-liquid separation tank 3 is a tank structure with a heat medium arranged on the outer circumference and a separation tank mechanical agitator 3-1 arranged inside. The inlet end of the upper end of the vapor-liquid separation tank 3 is connected to the outlet end of the first tubular reactor 2-4, and the vapor outlet end of the upper end of the vapor-liquid separation tank 3 is connected to the vapor inlet end of the light component separation tower system 6 through the separation tank condenser 3-2. The outlet end of the bottom end of the vapor-liquid separation tank 3 is connected to the two second Laval nozzles 4-1 of the second high-speed jet impact tubular reactor 4 through the second power fluid pump 3-3. The vapor-liquid separation tank 3 is used to separate methanol vapor, dimethyl carbonate vapor generated by the reaction from the ester exchange liquid; the ester exchange liquid coming out of the first high-speed jet impact tubular reactor 2 continuously enters the liquid inlet at the upper end of the vapor-liquid separation tank 3, and the vapor-liquid separation tank 3 separates the methanol vapor, dimethyl carbonate vapor generated by the reaction from the ester exchange liquid, and the separated vapor enters the light component separation tower system 6 through the separation tank condenser 3-2, and the ester exchange liquid separated from the light component enters the second high-speed jet impact tubular reactor 4 through the power fluid pump 3-3.

The structure of the second high-speed jet impact tubular reactor 4 is consistent with that of the first high-speed jet impact tubular reactor 2. The second high-speed jet impact tubular reactor 4 includes a second Laval nozzle 4-1, a second mixing chamber 4-2, a second high-speed jet impact chamber 4-3, a second tubular reactor 4-4, and a second heater 4-5; the second Laval nozzle 4-1, the second mixing chamber 4-2, the second high-speed jet impact chamber 4-3 and the second tubular reactor 4-4 are all arranged inside the second heater 4-5, the two second Laval nozzles 4-1 are arranged opposite to each other and connected, and the cavity formed at the middle connecting part is the second mixing chamber 4-2, the middle part of the second mixing chamber 4-2 is connected to the second high-speed jet impact chamber 4-3 in the vertical direction, the second high-speed jet impact chamber 4-3 is connected to one end of the second tubular reactor 4-4, and the other end of the second tubular reactor 4-4 is connected to the liquid inlet at the top of the maturation tank 5. The pipe openings of the two second Laval nozzles 4-1 are connected to the liquid outlet at the bottom of the vapor-liquid separation tank 3 through the second power fluid pump 3-3, and the pipe openings of the two second Laval nozzles 4-1 are provided with steam inlets, which are connected to the outlet end of the methanol vaporizer 7-6 of the methanol distillation tower system 7. The second high-speed jet impact tubular reactor 4 is used for transesterification reaction.

The two second Laval nozzles 4-1 are connected to the liquid outlet at the bottom of the vapor-liquid separation tank 3 through the second power fluid pump 3-3, and are connected to the outlet end of the methanol vaporizer 7-6 of the methanol distillation tower system 7. The mixed liquid in the vapor-liquid separation tank 3 is pumped into the two opposing second Laval nozzles 4-1 through the second power fluid pump 3-3. The steam inlets of the two opposing second Laval nozzles 4-1 simultaneously inhale the methanol vapor vaporized at the outlet end of the methanol vaporizer 7-6 of the methanol distillation tower system 7. The two high-speed jets ejected from the second Laval nozzles 4-1 (the ester exchange liquid in the vapor-liquid separation tank 3 and the methanol vapor in the methanol distillation tower system 7) collide with each other in the high-speed jet impact chamber 4-3 through the second mixing chamber 4-2, and then enter the second tubular reactor 4-4 for ester exchange reaction, and the ester exchange liquid continuously enters the maturation tank 5.

The maturation tank 5 is a tank structure with a heat medium arranged on the outer circumference and a mechanical stirrer 5-1 arranged inside the maturation tank; the top liquid inlet of the maturation tank 5 is connected to the outlet end of the second tubular reactor 4-4 of the second high-speed jet impact tubular reactor 4, and the upper overflow port of the maturation tank 5 is connected to the top liquid inlet of the light component separation tower kettle 6-1; the maturation tank 5 is used to continue to carry out supplementary ester exchange reaction; the ester exchange liquid coming out of the second high-speed jet impact tubular reactor 4 continuously enters the maturation tank 5, and the supplementary ester exchange reaction continues in the maturation tank 5; the ester exchange material overflowing from the maturation tank 5 enters the light component separation tower system 6 kettle.

The light component separation tower system 6 comprises a light component separation tower kettle 6-1, a light component white steel structured packing tower 6-2, a light component condenser 6-3, a light component receiving tank 6-4, a light component liquid pump 6-5 and a light component separation tower bottom pump 6-6; the light component separation tower kettle 6-1 is a structure with a heat medium arranged on the outer circumference, the top liquid inlet of the light component separation tower kettle 6-1 is connected with the upper overflow port of the maturation tank 5, the bottom liquid outlet of the light component separation tower kettle 6-1 is connected with the liquid inlet of the light component separation tower bottom pump 6-6, the outlet of the light component separation tower bottom pump 6-6 is connected with the liquid reflux inlet of the light component separation tower kettle 6-1, and the outlet end of the light component separation tower bottom pump 6-6 is connected with the ethylene glycol fine The liquid inlet of the distillation tower system 9; the upper end of the light component separation tower kettle 6-1 is connected to the light component white steel structured packing tower 6-2, the steam inlet end of the light component white steel structured packing tower 6-2 is connected to the outlet end of the separation tank condenser 3-2, the steam outlet end of the light component white steel structured packing tower 6-2 is connected to the inlet end of the light component condenser 6-3, the outlet end of the light component condenser 6-3 is connected to the inlet end of the light component receiving tank 6-4, the outlet end of the light component receiving tank 6-4 is connected to the outlet end of the light component liquid pump 6-5, the outlet end of the light component liquid pump 6-5 is connected to the upper reflux liquid inlet of the light component white steel structured packing tower 6-2, and the outlet end of the light component liquid pump 6-5 is also connected to the liquid inlet of the methanol distillation tower system 7. The light component separation tower system 6 is used for separating the light components of the ester exchange liquid in the vapor-liquid separation tank 3 and the maturation tank 5; the light component vapor separated by the light component separation tower system 6 is condensed by the condenser 6-3 and enters the light component liquid receiving tank 6-4, part of which is used as the reflux of the light component separation tower system 6, and part of which enters the methanol distillation tower system 7; the bottom liquid of the light component separation tower system 6 continuously enters the ethylene glycol distillation tower system 9 through the light component separation tower bottom pump 6-6.

The methanol distillation tower system 7 comprises a methanol distillation tower reboiler 7-1, a methanol distillation tower white steel structured packing tower 7-2, a methanol distillation tower condenser 7-3, a methanol distillation tower azeotropic liquid receiving tank 7-4, a methanol distillation tower azeotropic liquid pump 7-5, a methanol vaporizer 7-6, and a methanol distillation tower bottom pump 7-7; the middle liquid inlet of the methanol distillation tower system 7 is connected to the outlet end of the light component liquid pump 6-5 of the light component separation tower system 6 and is also connected to the outlet end of the dimethyl carbonate distillation tower azeotropic liquid pump 8-5 of the dimethyl carbonate distillation tower system 8; the top of the methanol distillation tower white steel structured packing tower 7-2 is connected to the outlet end of the dimethyl carbonate distillation tower azeotropic liquid pump 8-5 of the dimethyl carbonate distillation tower system 8; The steam outlet is connected to the inlet end of the methanol distillation tower condenser 7-3, the outlet end of the methanol distillation tower condenser 7-3 is connected to the inlet end of the top of the methanol distillation tower azeotropic liquid receiving tank 7-4, the outlet end of the methanol distillation tower azeotropic liquid receiving tank 7-4 at the bottom is connected to the inlet end of the methanol distillation tower azeotropic liquid pump 7-5, the outlet end of the methanol distillation tower azeotropic liquid pump 7-5 is connected to the upper reflux liquid inlet of the methanol distillation tower white steel structured packing tower 7-2 is also connected to the liquid inlet in the middle of the dimethyl carbonate distillation tower system 8; the bottom liquid outlet of the methanol distillation tower white steel structured packing tower 7-2 is connected to the bottom of the methanol distillation tower The inlet end of the methanol distillation tower bottom pump 7-7 and the outlet end of the methanol distillation tower bottom pump 7-7 are connected to the inlet end of the methanol distillation tower reboiler 7-1, the methanol distillation tower reboiler 7-1 is a structure provided with a heat medium, and the outlet end of the methanol distillation tower reboiler 7-1 is connected to the reboiled liquid reflux port of the methanol distillation tower white steel structured packing tower 7-2; the outlet end of the methanol distillation tower bottom pump 7-7 is also connected to the inlet end of the methanol vaporizer 7-6, the inlet end of the methanol vaporizer 7-6 is also connected to the inlet end of the fresh methanol, and the outlet end of the methanol vaporizer 7-6 is respectively connected to the first Laval nozzle 2-1 and the second Laval nozzle 4-1 Gas inlet end; the methanol distillation tower system 7 is used to distill methanol from the azeotropic liquid; the azeotropic vapor separated from the top of the methanol distillation tower system 7 is condensed by the methanol distillation tower condenser 7-3 and enters the methanol distillation tower azeotropic liquid receiving tank 7-4, part of which is used as the reflux of the methanol distillation tower system 7, and part of which enters the dimethyl carbonate distillation tower system 8; the bottom liquid of the methanol distillation tower system 7 enters the methanol vaporizer 7-6 through the methanol distillation tower bottom pump 7-7, and the vaporized methanol is continuously used for the ester exchange reaction of the first high-speed jet impact tubular reactor 2 and the second high-speed jet impact tubular reactor 4.

The dimethyl carbonate distillation tower system 8 comprises a dimethyl carbonate distillation tower reboiler 8-1, a dimethyl carbonate distillation tower white steel structured packing tower 8-2, a dimethyl carbonate distillation tower condenser 8-3, a dimethyl carbonate distillation tower azeotropic liquid receiving tank 8-4, a dimethyl carbonate distillation tower azeotropic liquid pump 8-5, a dimethyl carbonate storage tank 8-6 and a dimethyl carbonate distillation tower bottom pump 8-7; the middle liquid inlet of the dimethyl carbonate distillation tower white steel structured packing tower 8-2 is connected to the outlet end of the methanol distillation tower azeotropic liquid pump 7-5; the dimethyl carbonate distillation tower white steel structured packing tower 8- The top steam outlet of the dimethyl carbonate distillation tower is connected to the inlet end of the condenser 8-3 of the dimethyl carbonate distillation tower, the outlet end of the condenser 8-3 of the dimethyl carbonate distillation tower is connected to the inlet end of the top of the azeotropic liquid receiving tank 8-4 of the dimethyl carbonate distillation tower, the outlet end of the azeotropic liquid receiving tank 8-4 of the dimethyl carbonate distillation tower is connected to the inlet end of the azeotropic liquid pump 8-5 of the dimethyl carbonate distillation tower, the outlet end of the azeotropic liquid pump 8-5 of the dimethyl carbonate distillation tower is connected to the upper reflux liquid inlet of the white steel structured packing tower 8-2 of the dimethyl carbonate distillation tower, and the outlet end of the azeotropic liquid pump 8-5 of the dimethyl carbonate distillation tower is also connected to the top of the reflux liquid inlet of the white steel structured packing tower 8-2 of the dimethyl carbonate distillation tower. The liquid inlet in the middle of the methanol distillation tower system 7 is connected; the bottom liquid outlet of the white steel structured packing tower 8-2 of the dimethyl carbonate distillation tower is connected to the inlet end of the bottom pump 8-7 of the dimethyl carbonate distillation tower, and the outlet end of the bottom pump 8-7 of the dimethyl carbonate distillation tower is connected to the inlet end of the reboiler 8-1 of the dimethyl carbonate distillation tower. The reboiler 8-1 of the dimethyl carbonate distillation tower is a structure provided with a heat medium, and the outlet end of the reboiler 8-1 of the dimethyl carbonate distillation tower is connected to the reboiled liquid reflux port of the white steel structured packing tower 8-2 of the dimethyl carbonate distillation tower; the outlet end of the bottom pump 8-7 of the dimethyl carbonate distillation tower It is also connected to the top inlet end of the dimethyl carbonate storage tank 8-6; the dimethyl carbonate distillation tower system 8 is used to distill dimethyl carbonate from the azeotropic liquid; the azeotropic vapor separated from the top of the dimethyl carbonate distillation tower system 8 is condensed by the dimethyl carbonate distillation tower condenser 8-3 and enters the dimethyl carbonate distillation tower azeotropic liquid receiving tank 8-4, part of which is used as reflux of the dimethyl carbonate distillation tower system 8, and part of which is returned to the methanol distillation tower system 7 as feed; the bottom liquid of the dimethyl carbonate distillation tower system 8 enters the dimethyl carbonate storage tank 8-6 through the dimethyl carbonate distillation tower bottom pump 8-7.

The ethylene glycol distillation tower system 9 includes an ethylene glycol distillation tower reboiler 9-1, an ethylene glycol distillation tower white steel structured packing tower 9-2, an ethylene glycol distillation tower condenser 9-3, an ethylene glycol receiving tank 9-4, an ethylene glycol pump 9-5, an ethylene glycol storage tank 9-6 and an ethylene glycol distillation tower bottom pump 9-7. The liquid inlet in the middle of the ethylene glycol distillation tower system 9 is connected to the outlet end of the light component separation tower bottom pump 6-6; the top steam outlet of the ethylene glycol distillation tower white steel structured packing tower 9-2 is connected to the inlet end of the ethylene glycol distillation tower condenser 9-3, the outlet end of the ethylene glycol distillation tower condenser 9-3 is connected to the inlet end of the top of the ethylene glycol receiving tank 9-4, the outlet end of the bottom of the ethylene glycol receiving tank 9-4 is connected to the inlet end of the ethylene glycol pump 9-5, and the outlet end of the ethylene glycol pump 9-5 is connected to the outlet end of the ethylene glycol pump 9-5. The upper reflux liquid inlet of the white steel structured packing tower 9-2 of the ethylene glycol distillation tower is connected, and the outlet end of the ethylene glycol pump 9-5 is also connected to the top inlet end of the ethylene glycol storage tank 9-6; the bottom liquid outlet of the white steel structured packing tower 9-2 of the ethylene glycol distillation tower is connected to the inlet end of the bottom pump 9-7 of the ethylene glycol distillation tower, and the outlet end of the bottom pump 9-7 of the ethylene glycol distillation tower is connected to the inlet end of the reboiler 9-1 of the ethylene glycol distillation tower, and the reboiler 9-1 of the ethylene glycol distillation tower is a structure provided with a heat medium The outlet end of the reboiler 9-1 of the ethylene glycol distillation tower is connected to the reboiled liquid reflux port of the white steel structured packing tower 9-2 of the ethylene glycol distillation tower; the outlet end of the bottom pump 9-7 of the ethylene glycol distillation tower is also connected to the top inlet end of the batching tank 1; the ethylene glycol distillation tower system 9 is used to distill ethylene glycol from the bottom liquid of the light component separation tower system 6; the bottom liquid of the light component separation tower system 6 is continuously pumped into the ethylene glycol distillation tower system 9 through the bottom pump 6-6 of the light component separation tower, and the ethylene glycol distillation tower The ethylene glycol vapor separated from the top of system 9 is condensed by the ethylene glycol distillation tower condenser 9-3 and enters the ethylene glycol receiving tank 9-4, part of which is used as reflux of the ethylene glycol distillation tower system 9, and part of which is fed into the ethylene glycol storage tank 9-6; the bottom liquid of the ethylene glycol distillation tower system 9 is partially fed into the ethylene glycol distillation tower reboiler 9-1 through the ethylene glycol distillation tower bottom pump 9-7, and then returns to the ethylene glycol distillation tower system 9 after heating, and part of which is continuously fed into the batching tank 1 as a recovered catalyst.

The raw materials used in the present invention are industrial ethylene carbonate (mass content greater than 99.5%), industrial methanol (mass content greater than 99.5%), catalysts, etc.; the public engineering water vapor used is 0.4MPa, 290°C superheated water vapor; the public engineering water vapor is mainly used as the heat medium of the batching tank 1, the first heater 2-5 of the first high-speed jet impact tubular reactor 2, the heat medium of the vapor-liquid separation tank 3, the second heater 4-5 of the second high-speed jet impact tubular reactor 4, the heat medium of the maturation tank 5, the heat medium of the light component separation tower system 6, the heat medium of the methanol distillation tower system 7, the heat medium of the dimethyl carbonate distillation tower system 8, and the heat medium of the ethylene glycol distillation tower system 9 to provide heat sources; the various devices of the device are connected by corresponding pipelines. When the pipelines in Figure 1 cross on the figure but do not actually intersect, they are drawn according to the principle of vertical and horizontal interruption. The heat medium structure is the existing jacket structure; the heat medium structure of the tower kettle is the existing reboiler structure.

A method for producing dimethyl carbonate based on the above device specifically comprises the following steps:

(1) Adding raw materials of ethylene carbonate and catalyst into a batching tank 1, wherein the temperature in the batching tank 1 is 70° C. to 75° C. and the pressure is normal pressure, and the ethylene carbonate and catalyst are uniformly mixed under the stirring action of a mechanical stirrer 1-1 to obtain a mixed liquid; the mixed liquid reaches the reaction temperature under the heating of a heat medium, and the residence time of the materials is 0.5 h to 0.75 h; and the mixed liquid continuously enters the first high-speed jet impact tubular reactor 2 through a power fluid pump 1-2;

(2) The mixed liquid in the batching tank 1 is pumped into two opposing first Laval nozzles 2-1 through a power fluid pump 1-2. The steam inlet of the first Laval nozzle 2-1 simultaneously inhales methanol vapor from the methanol distillation tower system 7. The two high-speed jets ejected from the first Laval nozzle 2-1 collide with each other in the high-speed jet impact chamber and then enter the tubular reactor 2-4 for ester exchange reaction to obtain ester exchange liquid. The ester exchange liquid continuously enters the vapor-liquid separation tank 3. The temperature in the first high-speed jet impact tubular reactor 2 is 80° C. to 85° C. and the pressure is 0.2 MPa to 0.25 MPa.

(3) The vapor-liquid separation tank 3 separates the unreacted methanol vapor, the dimethyl carbonate vapor generated by the reaction and the transesterification liquid, and the separated vapor enters the light component separation tower system 6; the transesterification liquid with separated light components continuously enters the two opposite second Laval nozzles 4-1 of the second high-speed jet impact tubular reactor 4 through the second power fluid pump 3-3; the temperature in the vapor-liquid separation tank 3 is 70°C to 75°C, the pressure is normal pressure, and the residence time of the material is 0.5h to 0.75h;

(4) The steam inlet of the second Laval nozzle 4-1 simultaneously sucks in methanol vapor from the methanol distillation tower system 7. The two high-speed jets ejected from the second Laval nozzle 4-1 collide with each other in the high-speed jet impact chamber and then enter the second tubular reactor 4-4 for transesterification reaction. The transesterification liquid from the second high-speed jet impact tubular reactor 4 continuously enters the maturation tank 5. The temperature in the second high-speed jet impact tubular reactor 4 is 80° C. to 85° C., and the pressure is 0.2 MPa to 0.25 MPa.

(5) The ester exchange liquid continues to undergo supplementary ester exchange reaction in the maturation tank 5; the aging liquid overflowing from the maturation tank 5 enters the kettle of the light component separation tower system 6; the temperature in the maturation tank 5 is 80°C to 85°C, the pressure is 0.2MPa to 0.25MPa, and the residence time of the material is 1.5h to 2h;

(6) The materials from the vapor-liquid separation tank 3 and the maturation tank 5 continuously enter the light component separation tower system 6. The light component vapor separated by the light component separation tower system 6 is condensed by the condenser 6-3 and enters the light component liquid receiving tank 6-4. The obtained light component liquid is used as the reflux of the light component separation tower system 6 and enters the methanol distillation tower system 7; the bottom liquid of the light component separation tower system 6 continuously enters the ethylene glycol distillation tower system 9 through the light component separation tower bottom pump 6-6; the bottom temperature of the light component separation tower system 6 is 75°C to 78°C, the top temperature is 64°C to 66°C, the reflux ratio is 3 to 4, and the pressure is normal pressure;

(7) The light component liquid from the light component separation tower system 6 continuously enters the methanol distillation tower system 7, and the azeotropic vapor separated from the top of the methanol distillation tower system 7 is condensed by the methanol distillation tower condenser 7-3 and enters the methanol distillation tower azeotropic liquid receiving tank 7-4. The obtained azeotropic liquid is used as the reflux of the methanol distillation tower system 7 and enters the dimethyl carbonate distillation tower system 8; the bottom liquid of the methanol distillation tower system 7 enters the methanol vaporizer 7-6 through the methanol distillation tower bottom pump 7-7, and the vaporized methanol enters the gas inlet of the first Laval nozzle 2-1 and the second Laval nozzle 4-1 to continue to be used for the ester exchange reaction; the bottom temperature of the methanol distillation tower system 7 is 70°C, and the bottom pressure is 0.13MPa; the top temperature is 64°C, the top pressure is normal pressure, and the reflux ratio is 2;

(8) The azeotropic liquid from the methanol distillation tower system 7 continuously enters the dimethyl carbonate distillation tower system 8, and the azeotropic liquid vapor separated from the top of the dimethyl carbonate distillation tower system 8 is condensed by the dimethyl carbonate distillation tower condenser 8-3 and enters the dimethyl carbonate distillation tower azeotropic liquid receiving tank 8-4, and the obtained azeotropic liquid is used as the reflux of the dimethyl carbonate distillation tower system 8 and as the feed to return to the methanol distillation tower system 7; the bottom liquid of the dimethyl carbonate distillation tower system 8 enters the dimethyl carbonate storage tank 8-6 through the dimethyl carbonate distillation tower bottom pump 8-7; the bottom temperature of the dimethyl carbonate distillation tower system 8 is 183°C, the bottom pressure is 1.33MPa; the top temperature is 147°C, the top pressure is 1.30MPa, and the reflux ratio is 1.2;

(9) The bottom liquid from the light component separation tower system 6 continuously enters the ethylene glycol distillation tower system 9. The ethylene glycol vapor separated from the top of the ethylene glycol distillation tower system 9 is condensed by the ethylene glycol distillation tower condenser 9-3 and enters the ethylene glycol receiving tank 9-4. The obtained ethylene glycol is used as the reflux of the ethylene glycol distillation tower system 9 and the feed to the ethylene glycol storage tank 9-6. The bottom liquid of the ethylene glycol distillation tower system 9 enters the ethylene glycol distillation tower reboiler 9-1 through the ethylene glycol distillation tower bottom pump 9-7 and returns to the ethylene glycol distillation tower system 9 after heating, and continuously enters the batching tank 1 as a recovered catalyst. The top temperature of the ethylene glycol distillation tower system 9 is 150°C, the top pressure is 0.02MPa; the bottom temperature is 178°C, and the reflux ratio is 1.5.

Example 1

The method for producing dimethyl carbonate based on a device for preparing dimethyl carbonate using a high-speed jet impingement tubular reactor comprises the following steps:

In the step (1), 176 kg/h of industrial-grade ethylene carbonate (mass content greater than 99.5%) and 0.44 kg/h of catalyst are introduced into a batching tank 1, and the ethylene carbonate and the catalyst are uniformly mixed under stirring; the mixed liquid reaches the reaction temperature under the heating of a heat medium, and enters the first high-speed jet impact tubular reactor 2 through a first power fluid pump 1-2; the temperature in the batching tank 1 is 70° C., the pressure is normal pressure, the amount of catalyst is 0.25% of the mass of the ethylene carbonate, and the residence time of the material is 0.75 h;

In the step (2), the mixed liquid from the batching tank 1 continuously enters the first high-speed jet impact tubular reactor 2; the mixed liquid from the batching tank 1 is pumped into two opposing first Laval nozzles 2-1 by the first power fluid pump 1-2, and the steam inlet simultaneously sucks methanol (mass content greater than 99.5%) vapor, and the two high-speed jets ejected from the Laval tubes collide with each other in the high-speed jet impact chamber, and then enter the first tubular reactor 2-4 for ester exchange reaction, and the ester exchange liquid continuously enters the vapor-liquid separation tank 3; the temperature in the first high-speed jet impact tubular reactor 2 is 80° C., the pressure is 0.2 MPa, the length-to-diameter ratio of the first tubular reactor 2-4 is 1000, the ethylene carbonate:methanol ratio is 1:4.4 (molar ratio), and the methanol is 282 kg/h;

In the step (3), the ester exchange liquid from the first high-speed jet impact tubular reactor 2 continuously enters the vapor-liquid separation tank 3, and the vapor-liquid separation tank 3 separates the methanol vapor and the dimethyl carbonate vapor generated by the reaction from the ester exchange liquid, and the separated vapor enters the light component separation tower system 6; the ester exchange liquid with the separated light component enters the second high-speed jet impact tubular reactor 4 through the second power fluid pump 3-3; the temperature in the vapor-liquid separation tank 3 is 70° C., the pressure is normal pressure, and the residence time of the material is 0.75h;

In the step (4), the ester exchange liquid from which the light components are separated from the vapor-liquid separation tank 3 continuously enters the second high-speed jet impact tubular reactor 4; the ester exchange liquid after the vapor is separated in the vapor-liquid separation tank 3 is pumped into two opposing second Laval nozzles 4-1 through the second power fluid pump 3-3, and the steam inlet simultaneously sucks methanol vapor, and the two high-speed jets ejected from the second Laval tube 4-1 collide with each other in the high-speed jet impact chamber, and then enter the second tubular reactor 4-4 for ester exchange reaction, and the ester exchange liquid from the second high-speed jet impact tubular reactor 4 continuously enters the maturation tank 5; the temperature in the second high-speed jet impact tubular reactor 4 is 80° C., the pressure is 0.2 MPa, the length-to-diameter ratio of the second tubular reactor 4-4 is 1000, the ethylene carbonate:methanol ratio is 1:4.4 (molar ratio), and the methanol is 282 kg/h;

In the step (5), the ester exchange liquid from the second high-speed jet impact tubular reactor 4 continuously enters the maturation tank 5, and the supplementary ester exchange reaction continues in the maturation tank 5; the aging liquid overflowing from the maturation tank 5 enters the kettle of the light component separation tower system 6; the temperature in the maturation tank 5 is 80° C., the pressure is 0.2 MPa, and the residence time of the material is 2 hours;

In the step (6), the materials from the vapor-liquid separation tank 3 and the maturation tank 5 continuously enter the light component separation tower system 6, and the light component vapor separated by the light component separation tower system 6 is condensed by the light component condenser 6-3 and enters the light component liquid receiving tank 6-4, part of which is used as the reflux of the light component separation tower system 6, and part of which enters the methanol distillation tower system 7; the bottom liquid of the light component separation tower system 6 continuously enters the ethylene glycol distillation tower system 9 through the light component separation tower bottom pump 6-6; the bottom temperature of the light component separation tower system 6 is 75°C, the top temperature is 64°C, the reflux ratio is 3, and the pressure is normal pressure;

In the step (7), the azeotropic liquid from the light component separation tower system 6 continuously enters the methanol distillation tower system 7, and the azeotropic vapor separated from the top of the methanol distillation tower system 7 is condensed by the methanol distillation tower condenser 7-3 and enters the methanol distillation tower azeotropic liquid receiving tank 7-4, part of which is used as the reflux of the methanol distillation tower system 7, and part of which enters the dimethyl carbonate distillation tower system 8; the bottom liquid of the methanol distillation tower system 7 enters the methanol vaporizer 7-6 through the methanol distillation tower bottom pump 7-7, and the vaporized methanol is continuously used for the transesterification reaction; the bottom temperature of the methanol distillation tower system 7 is 70°C, and the bottom pressure is 0.13MPa; the top temperature is 64°C, the top pressure is normal pressure, and the reflux ratio is 2;

In the step (8), the azeotropic liquid from the methanol distillation tower system 7 continuously enters the dimethyl carbonate distillation tower system 8, the azeotropic liquid vapor separated from the top of the dimethyl carbonate distillation tower system 8 is condensed by the dimethyl carbonate distillation tower condenser 8-3 and enters the dimethyl carbonate distillation tower azeotropic liquid receiving tank 8-4, part of which is used as reflux of the dimethyl carbonate distillation tower system 8, and part of which is returned to the methanol distillation tower system 7 as feed; the bottom liquid of the dimethyl carbonate distillation tower system 8 enters the dimethyl carbonate storage tank 8-6 through the dimethyl carbonate distillation tower bottom pump 8-7; the bottom temperature of the dimethyl carbonate distillation tower system 8 is 183° C., and the bottom pressure is 1.33 MPa; the top temperature is 147° C., the top pressure is 1.30 MPa, and the reflux ratio is 1.2; 172 kg/h of dimethyl carbonate is produced;

In the step (9), the bottom liquid from the light component separation tower system 6 continuously enters the ethylene glycol distillation tower system 9, and the ethylene glycol vapor separated from the top of the ethylene glycol distillation tower system 9 is condensed by the condenser 9-3 and enters the ethylene glycol receiving tank 9-4, part of which is used as reflux of the ethylene glycol distillation tower system 9, and part of which is fed into the ethylene glycol storage tank 9-6; the bottom liquid of the ethylene glycol distillation tower system 9 is partially entered into the ethylene glycol distillation tower reboiler 9-1 through the ethylene glycol distillation tower bottom pump 9-7, and then returns to the ethylene glycol distillation tower system 9 after heating, and part of which is continuously entered into the batching tank 1 as a recovered catalyst; the top temperature of the ethylene glycol distillation tower system 9 is 150°C, and the top pressure is 0.02MPa; the bottom temperature is 178°C, and the reflux ratio is 1.5.

In this embodiment 1, the yield of dimethyl carbonate is greater than 95%.

Example 2

The method for producing dimethyl carbonate based on the device for preparing dimethyl carbonate using the high-speed jet impingement tubular reactor comprises the following steps:

In the step (1), 176 kg/h of industrial-grade ethylene carbonate (mass content greater than 99.5%) and 0.27 kg/h of catalyst are introduced into a batching tank 1, and the ethylene carbonate and the catalyst are uniformly mixed under stirring; the mixed liquid reaches the reaction temperature under the heating of a heat medium, and enters the first high-speed jet impact tubular reactor 2 through a first power fluid pump 1-2; the temperature in the batching tank 1 is 75° C., the pressure is normal pressure, the amount of catalyst is 0.15% of the mass of the ethylene carbonate, and the residence time of the material is 0.5 h;

In the step (2), the mixed liquid from the batching tank 1 continuously enters the first high-speed jet impact tubular reactor 2; the mixed liquid from the batching tank 1 is pumped into two opposing first Laval nozzles 2-1 by the first power fluid pump 1-2, and methanol (mass content greater than 99.5%) vapor is sucked in at the same time, and the two high-speed jets ejected from the first Laval tube 2-1 collide with each other in the high-speed jet impact chamber, and then enter the first tubular reactor 2-4 for ester exchange reaction, and the ester exchange liquid continuously enters the vapor-liquid separation tank 3; the temperature in the first high-speed jet impact tubular reactor 2 is 85° C., the pressure is 0.25 MPa, the length-to-diameter ratio of the first tubular reactor 2-4 is 1000, the ethylene carbonate:methanol ratio is 1:4 (molar ratio), and the methanol is 256 kg/h;

In the step (3), the ester exchange liquid from the first high-speed jet impact tubular reactor 2 continuously enters the vapor-liquid separation tank 3, and the vapor-liquid separation tank 3 separates the methanol vapor and the dimethyl carbonate vapor generated by the reaction from the ester exchange liquid, and the separated vapor enters the light component separation tower system 6; the ester exchange liquid with the separated light component enters the second high-speed jet impact tubular reactor 4 through the second power fluid pump 3-3; the temperature in the vapor-liquid separation tank 3 is 75° C., the pressure is normal pressure, and the residence time of the material is 0.5h;

In the step (4), the ester exchange liquid from which the light components are separated from the vapor-liquid separation tank 3 continuously enters the second high-speed jet impact tubular reactor 4; the ester exchange liquid after the vapor is separated in the vapor-liquid separation tank 3 is pumped into two opposing second Laval nozzles 4-1 through the second power fluid pump 3-3, and methanol vapor is sucked in at the same time, and the two high-speed jets ejected from the second Laval tube 4-1 collide with each other in the high-speed jet impact chamber, and then enter the second tubular reactor 4-4 for ester exchange reaction, and the ester exchange liquid from the second high-speed jet impact tubular reactor 4 continuously enters the maturation tank 5; the temperature in the second high-speed jet impact tubular reactor 4 is 85° C., the pressure is 0.25 MPa, the length-to-diameter ratio of the second tubular reactor 4-4 is 1000, the ethylene carbonate:methanol ratio is 1:4 (molar ratio), and the methanol is 256 kg/h;

In the step (5), the ester exchange liquid from the second high-speed jet impact tubular reactor 4 continuously enters the maturation tank 5, and the supplementary ester exchange reaction continues in the maturation tank 5; the aging liquid overflowing from the maturation tank 5 enters the kettle of the light component separation tower system 6; the temperature in the maturation tank 5 is 85° C., the pressure is 0.25 MPa, and the residence time of the material is 1.5 h;

In the step (6), the materials from the vapor-liquid separation tank 3 and the maturation tank 5 continuously enter the light component separation tower system 6, and the light component vapor separated by the light component separation tower system 6 is condensed by the light component condenser 6-3 and enters the light component receiving tank 6-4, part of which is used as the reflux of the light component separation tower system 6, and part of which enters the methanol distillation tower system 7; the bottom liquid of the light component separation tower system 6 continuously enters the ethylene glycol distillation tower system 9 through the bottom pump of the separation tower; the bottom temperature of the light component separation tower system 6 is 78° C., the top temperature is 66° C., the reflux ratio is 4, and the pressure is normal pressure;

In the step (7), the azeotropic liquid from the light component separation tower system 6 continuously enters the methanol distillation tower system 7, and the azeotropic vapor separated from the top of the methanol distillation tower system 7 is condensed by the methanol distillation tower condenser 7-3 and enters the methanol distillation tower azeotropic liquid receiving tank 7-4, part of which is used as the reflux of the methanol distillation tower system 7, and part of which enters the dimethyl carbonate distillation tower system 8; the bottom liquid of the methanol distillation tower system 7 enters the methanol vaporizer through the methanol distillation tower bottom pump 7-7, and the vaporized methanol is continuously used for the transesterification reaction; the bottom temperature of the methanol distillation tower system 7 is 70°C, and the bottom pressure is 0.13MPa; the top temperature is 64°C, the top pressure is normal pressure, and the reflux ratio is 2;

In the step (8), the azeotropic liquid from the methanol distillation tower system 7 continuously enters the dimethyl carbonate distillation tower system 8, the azeotropic liquid vapor separated from the top of the dimethyl carbonate distillation tower system 8 is condensed by the dimethyl carbonate distillation tower condenser 8-3 and enters the dimethyl carbonate distillation tower azeotropic liquid receiving tank 8-4, part of which is used as reflux of the dimethyl carbonate distillation tower system 8, and part of which is returned to the methanol distillation tower system 7 as feed; the bottom liquid of the dimethyl carbonate distillation tower system 8 enters the dimethyl carbonate storage tank 8-6 through the dimethyl carbonate distillation tower bottom pump 8-7; the bottom temperature of the dimethyl carbonate distillation tower system 8 is 183° C., and the bottom pressure is 1.33 MPa; the top temperature is 147° C., the top pressure is 1.30 MPa, and the reflux ratio is 1.2; 171.5 kg/h of dimethyl carbonate is produced;

In the step (9), the bottom liquid from the light component separation tower system 6 continuously enters the ethylene glycol distillation tower system 9, and the ethylene glycol vapor separated from the top of the ethylene glycol distillation tower system 9 is condensed by the ethylene glycol distillation tower condenser 9-3 and enters the ethylene glycol receiving tank 9-4, part of which is used as reflux of the ethylene glycol distillation tower system 9, and part of which is fed into the ethylene glycol storage tank 9-6; the bottom liquid of the ethylene glycol distillation tower system 9 is partially entered into the ethylene glycol distillation tower reboiler 9-1 through the ethylene glycol distillation tower bottom pump 9-7, and then returns to the ethylene glycol distillation tower system 9 after heating, and part of which is continuously entered into the batching tank 1 as a recovered catalyst; the top temperature of the ethylene glycol distillation tower system 9 is 150°C, and the top pressure is 0.02MPa; the bottom temperature is 178°C, and the reflux ratio is 1.5.

In this embodiment, the yield of dimethyl carbonate is greater than 95%.

The invention discloses a production method for preparing dimethyl carbonate by using a high-speed jet impact tubular reactor; the quality of dimethyl carbonate is higher than the standard of HG/T 5391-2018 industrial-grade dimethyl carbonate.

The above technical scheme illustrates the technical idea of the present invention, but cannot be used to limit the protection scope of the present invention. Any changes and modifications made to the above technical scheme based on the technical essence of the present invention without departing from the content of the technical scheme of the present invention shall fall within the protection scope of the technical scheme of the present invention.

Claims (8)

1. A device for preparing dimethyl carbonate by using a high-speed jet impinging tubular reactor, characterized in that the device comprises a batching tank (1), a first high-speed jet impinging tubular reactor (2), a vapor-liquid separation tank (3), a second high-speed jet impinging tubular reactor (4), a maturation tank (5), a light component separation tower system (6), a methanol distillation tower system (7) and a dimethyl carbonate distillation tower system (8) which are connected in sequence; at the same time, the batching tank (1) is connected to an ethylene glycol distillation tower system (9), the methanol distillation tower system (7) is connected to the first high-speed jet impinging tubular reactor (2) and the second high-speed jet impinging tubular reactor (4), the vapor-liquid separation tank (3) is connected to the light component separation tower system (6), and the light component separation tower system (6) is connected to the ethylene glycol distillation tower system (9); The batching tank (1), the vapor-liquid separation tank (3) and the maturation tank (5) have the same structure, and are all tank structures with a heat medium arranged on the outer circumference and a mechanical stirrer arranged inside; the top liquid inlet of the batching tank (1) is connected to the outlet end of the ethylene glycol distillation tower bottom pump (9-7) of the ethylene glycol distillation tower system (9); the bottom liquid outlet of the batching tank (1) is connected to the outlets of the two first Laval nozzles (2-1) of the first high-speed jet impact tubular reactor (2) through the first power fluid pump (1-2); The inlet end of the upper end of the vapor-liquid separation tank (3) is connected to the outlet end of the first tubular reactor (2-4) of the first high-speed jet impact tubular reactor (2), the vapor outlet end of the upper end of the vapor-liquid separation tank (3) is connected to the vapor inlet end of the light component separation tower system (6) through the separation tank condenser (3-2), and the outlet end of the bottom end of the vapor-liquid separation tank (3) is connected to the pipe openings of the two second Laval nozzles (4-1) of the second high-speed jet impact tubular reactor (4) through the second power fluid pump (3-3); The top liquid inlet of the maturation tank (5) is connected to the outlet end of the second tubular reactor (4-4) of the second high-speed jet impact tubular reactor (4), and the upper overflow port of the maturation tank (5) is connected to the top liquid inlet of the light component separation tower kettle (6-1) of the light component separation tower system (6); The first high-speed jet impact tubular reactor (2) and the second high-speed jet impact tubular reactor (4) have the same structure. The first high-speed jet impact tubular reactor (2) comprises a first Laval nozzle (2-1), a first mixing chamber (2-2), a first high-speed jet impact chamber (2-3), a first tubular reactor (2-4) and a first heater (2-5). The first Laval nozzle (2-1), the first mixing chamber (2-2), the first high-speed jet impact chamber (2-3) and the first tubular reactor (2-4) are all arranged inside the first heater (2-5). The Laval nozzles (2-1) are arranged opposite to each other and connected, and the cavity formed at the middle connecting portion is a first mixing chamber (2-2). The middle of the first mixing chamber (2-2) is connected to a first high-speed jet impact chamber (2-3) in a vertical direction. The first high-speed jet impact chamber (2-3) is connected to one end of a first tubular reactor (2-4). The other end of the first tubular reactor (2-4) is connected to a liquid inlet at the top of a vapor-liquid separation tank (3). Steam inlets are provided at the pipe openings of the two first Laval nozzles (2-1), and the steam inlets are connected to an outlet end of a methanol vaporizer (7-6) of a methanol distillation tower system (7). The second high-speed jet impact tubular reactor (4) comprises a second Laval nozzle (4-1), a second mixing chamber (4-2), a second high-speed jet impact chamber (4-3), a second tubular reactor (4-4), and a second heater (4-5); the second Laval nozzle (4-1), the second mixing chamber (4-2), the second high-speed jet impact chamber (4-3), and the second tubular reactor (4-4) are all arranged inside the second heater (4-5); the two second Laval nozzles (4-1) are arranged facing each other and connected; the cavity formed at the middle connecting portion is the second mixing chamber (4-2); the second mixing chamber (4-5) is connected to the second mixing chamber (4-2); The middle of the cavity (4-2) is connected to a second high-speed jet impact cavity (4-3) in the vertical direction, the second high-speed jet impact cavity (4-3) is connected to one end of a second tubular reactor (4-4), and the other end of the second tubular reactor (4-4) is connected to a liquid inlet at the top of a maturation tank (5); the pipe openings of the two second Laval nozzles (4-1) are connected to a liquid outlet at the bottom of a vapor-liquid separation tank (3) through a second power fluid pump (3-3), and steam inlets are provided at the pipe openings of the two second Laval nozzles (4-1), which are connected to an outlet end of a methanol vaporizer (7-6) of a methanol distillation tower system (7). 2. The device for preparing dimethyl carbonate by using a high-speed jet impingement tubular reactor according to claim 1, characterized in that: The first tubular reactor (2-4) has a length-to-diameter ratio of 1000, and the second tubular reactor (4-4) has a length-to-diameter ratio of 1000. 3. The device for preparing dimethyl carbonate by using a high-speed jet impingement tubular reactor according to claim 1, characterized in that: The light component separation tower system (6) comprises a light component separation tower kettle (6-1), a light component white steel structured packing tower (6-2), a light component condenser (6-3), a light component receiving tank (6-4), a light component liquid pump (6-5) and a light component separation tower bottom pump (6-6); the light component separation tower kettle (6-1) is a structure with a heat medium arranged on the outer circumference; the top liquid inlet of the light component separation tower kettle (6-1) is connected to the upper overflow port of the maturation tank (5); the bottom liquid outlet of the light component separation tower kettle (6-1) is connected to the liquid inlet of the light component separation tower bottom pump (6-6); the outlet of the light component separation tower bottom pump (6-6) is connected to the bottom liquid reflux inlet of the light component separation tower kettle (6-1); the outlet end of the light component separation tower bottom pump (6-6) is connected to the ethylene glycol fine The upper end of the light component separation tower kettle (6-1) is connected to the light component white steel structured packing tower (6-2) and is integrally arranged; the steam inlet end of the light component white steel structured packing tower (6-2) is connected to the outlet end of the separation tank condenser (3-2); the steam outlet end of the light component white steel structured packing tower (6-2) is connected to the inlet end of the light component condenser (6-3); the outlet end of the light component condenser (6-3) is connected to the inlet end of the light component receiving tank (6-4); the outlet end of the light component receiving tank (6-4) is connected to the outlet end of the light component liquid pump (6-5); the outlet end of the light component liquid pump (6-5) is connected to the upper reflux liquid inlet of the light component white steel structured packing tower (6-2); and the outlet end of the light component liquid pump (6-5) is also connected to the liquid inlet of the methanol distillation tower system (7). 4. The device for preparing dimethyl carbonate by using a high-speed jet impingement tubular reactor according to claim 3, characterized in that: the methanol distillation tower system (7) comprises a methanol distillation tower reboiler (7-1), a methanol distillation tower white steel structured packing tower (7-2), a methanol distillation tower condenser (7-3), a methanol distillation tower azeotropic liquid receiving tank (7-4), a methanol distillation tower azeotropic liquid pump (7-5), a methanol vaporizer (7-6) and a methanol distillation tower bottom pump (7-7); the middle of the methanol distillation tower system (7) The liquid inlet is connected to the outlet of the light component liquid pump (6-5) of the light component separation tower system (6) and is also connected to the outlet of the dimethyl carbonate distillation tower azeotropic liquid pump (8-5) of the dimethyl carbonate distillation tower system (8); the steam outlet at the top of the white steel structured packing tower (7-2) of the methanol distillation tower is connected to the inlet of the methanol distillation tower condenser (7-3), the outlet of the methanol distillation tower condenser (7-3) is connected to the inlet of the top of the methanol distillation tower azeotropic liquid receiving tank (7-4), and the bottom of the methanol distillation tower azeotropic liquid receiving tank (7-4) is connected to the inlet of the top of the methanol distillation tower azeotropic liquid receiving tank (7-4). The outlet end of the methanol distillation tower is connected to the inlet end of the azeotropic liquid pump (7-5), and the outlet end of the methanol distillation tower azeotropic liquid pump (7-5) is connected to the upper reflux liquid inlet of the white steel structured packing tower (7-2) of the methanol distillation tower and is also connected to the liquid inlet in the middle of the dimethyl carbonate distillation tower system (8); the bottom liquid outlet of the white steel structured packing tower (7-2) of the methanol distillation tower is connected to the inlet end of the bottom pump (7-7) of the methanol distillation tower, and the outlet end of the bottom pump (7-7) of the methanol distillation tower is connected to the inlet end of the reboiler (7-1) of the methanol distillation tower. The methanol distillation tower reboiler (7-1) is a structure provided with a heat medium, and the outlet end of the methanol distillation tower reboiler (7-1) is connected to the reboiled liquid reflux port of the white steel structured packing tower (7-2) of the methanol distillation tower; the outlet end of the methanol distillation tower bottom pump (7-7) is also connected to the inlet end of the methanol vaporizer (7-6), and the inlet end of the methanol vaporizer (7-6) is also connected to the inlet end of fresh methanol, and the outlet end of the methanol vaporizer (7-6) is respectively connected to the steam inlets of the first Laval nozzle (2-1) and the second Laval nozzle (4-1). 5. The device for preparing dimethyl carbonate by using a high-speed jet impingement tubular reactor according to claim 4, characterized in that: The dimethyl carbonate distillation tower system (8) comprises a dimethyl carbonate distillation tower reboiler (8-1), a dimethyl carbonate distillation tower white steel structured packing tower (8-2), a dimethyl carbonate distillation tower condenser (8-3), a dimethyl carbonate distillation tower azeotropic liquid receiving tank (8-4), a dimethyl carbonate distillation tower azeotropic liquid pump (8-5), a dimethyl carbonate storage tank (8-6) and a dimethyl carbonate distillation tower bottom pump (8-7); the dimethyl carbonate distillation tower white steel structured packing tower ( The middle liquid inlet of 8-2 is connected to the outlet of the azeotropic liquid pump (7-5) of the methanol distillation tower; the top steam outlet of the white steel structured packing tower (8-2) of the dimethyl carbonate distillation tower is connected to the inlet of the condenser (8-3) of the dimethyl carbonate distillation tower, the outlet of the condenser (8-3) of the dimethyl carbonate distillation tower is connected to the inlet of the top of the azeotropic liquid receiving tank (8-4) of the dimethyl carbonate distillation tower, and the outlet of the bottom of the azeotropic liquid receiving tank (8-4) of the dimethyl carbonate distillation tower is connected to the inlet of the top of the azeotropic liquid receiving tank (8-4) of the dimethyl carbonate distillation tower. The inlet end of the azeotropic liquid pump (8-5) of the ester distillation tower and the outlet end of the azeotropic liquid pump (8-5) of the dimethyl carbonate distillation tower are connected to the reflux liquid inlet of the upper part of the white steel structured packing tower (8-2) of the dimethyl carbonate distillation tower. The outlet end of the azeotropic liquid pump (8-5) of the dimethyl carbonate distillation tower is also connected to the liquid inlet of the middle part of the methanol distillation tower system (7); the bottom liquid outlet of the white steel structured packing tower (8-2) of the dimethyl carbonate distillation tower is connected to the inlet end of the bottom pump (8-7) of the dimethyl carbonate distillation tower. The outlet end of the bottom pump (8-7) of the dimethyl carbonate distillation tower is connected to the inlet end of the reboiler (8-1) of the dimethyl carbonate distillation tower. The reboiler (8-1) of the dimethyl carbonate distillation tower is a structure provided with a heat medium. The outlet end of the reboiler (8-1) of the dimethyl carbonate distillation tower is connected to the reboiled liquid reflux port of the white steel structured packing tower (8-2) of the dimethyl carbonate distillation tower. The outlet end of the bottom pump (8-7) of the dimethyl carbonate distillation tower is also connected to the top inlet end of the dimethyl carbonate storage tank (8-6). 6. The device for preparing dimethyl carbonate by using a high-speed jet impact tubular reactor according to claim 3, characterized in that: the ethylene glycol distillation tower system (9) comprises an ethylene glycol distillation tower reboiler (9-1), an ethylene glycol distillation tower white steel structured packing tower (9-2), an ethylene glycol distillation tower condenser (9-3), an ethylene glycol receiving tank (9-4), an ethylene glycol pump (9-5), an ethylene glycol storage tank (9-6) and an ethylene glycol distillation tower bottom pump (9-7); the liquid inlet in the middle of the ethylene glycol distillation tower system (9) is connected to the outlet end of the light component separation tower bottom pump (6-6); the top steam outlet of the ethylene glycol distillation tower white steel structured packing tower (9-2) is connected to the inlet end of the ethylene glycol distillation tower condenser (9-3), the outlet end of the ethylene glycol distillation tower condenser (9-3) is connected to the inlet end of the top of the ethylene glycol receiving tank (9-4), and the ethylene glycol receiving tank (9-5) is connected to the inlet end of the top of the ethylene glycol receiving tank (9-6). -4) The outlet end at the bottom is connected to the inlet end of the ethylene glycol pump (9-5), and the outlet end of the ethylene glycol pump (9-5) is connected to the upper reflux liquid inlet of the ethylene glycol distillation tower white steel structured packing tower (9-2). The outlet end of the ethylene glycol pump (9-5) is also connected to the top inlet end of the ethylene glycol storage tank (9-6); the bottom liquid outlet of the ethylene glycol distillation tower white steel structured packing tower (9-2) is connected to the inlet of the ethylene glycol distillation tower bottom pump (9-7) The outlet end of the ethylene glycol distillation tower bottom pump (9-7) is connected to the inlet end of the ethylene glycol distillation tower reboiler (9-1), the ethylene glycol distillation tower reboiler (9-1) is a structure provided with a heat medium, and the outlet end of the ethylene glycol distillation tower reboiler (9-1) is connected to the reboiled liquid reflux port of the ethylene glycol distillation tower white steel structured packing tower (9-2); the outlet end of the ethylene glycol distillation tower bottom pump (9-7) is also connected to the top inlet end of the batching tank (1). 7. A method for preparing dimethyl carbonate using a high-speed jet impinging tubular reactor as claimed in claim 1, characterized in that it specifically comprises the following steps: Step 1. The raw materials of ethylene carbonate and catalyst are put into a batching tank (1) and stirred and mixed to obtain a mixed liquid, wherein the amount of catalyst is 0.15% to 0.25% of the mass of ethylene carbonate; the mixed liquid reaches the reaction temperature under the heating of a heat medium, and continuously enters the first high-speed jet impact tubular reactor (2) through a first power fluid pump (1-2); Step 2. The mixed liquid in the batching tank (1) is pumped into two opposing first Laval nozzles (2-1) through a first power fluid pump (1-2), while methanol vapor is sucked in. The molar ratio of methanol to ethylene carbonate is (4 to 4.4):1. The two high-speed jets ejected from the first Laval nozzle (2-1) collide with each other in the first high-speed jet impact chamber (2-3), and then enter the first tubular reactor (2-4) to undergo an ester exchange reaction to obtain dimethyl carbonate vapor and an ester exchange liquid. The methanol vapor, the dimethyl carbonate vapor generated by the reaction, and the ester exchange liquid continuously enter the vapor-liquid separation tank (3); Step 3. The vapor-liquid separation tank (3) separates the methanol vapor, the dimethyl carbonate vapor generated by the reaction and the transesterification liquid, and the separated methanol vapor and the dimethyl carbonate vapor generated by the reaction enter the light component separation tower system (6); the transesterification liquid from which the light component is separated continuously enters the second high-speed jet impact tubular reactor (4) through the second power fluid pump (3-3); Step 4. The transesterification liquid in the vapor-liquid separation tank (3) is pumped into two opposing second Laval nozzles (4-1) through a second power fluid pump (3-3), while methanol vapor is sucked in. The amount of methanol added is the same as that in step 2. The two high-speed jets ejected from the second Laval nozzle (4-1) collide with each other in the second high-speed jet impact chamber (4-3), and then enter the second tubular reactor (4-4) for transesterification reaction. The methanol vapor from the second high-speed jet impact tubular reactor (4), the dimethyl carbonate vapor generated by the reaction, and the transesterification liquid continuously enter the maturation tank (5); Step 5. The ester exchange liquid continues to undergo supplementary ester exchange reaction in the aging tank (5); the aging liquid overflowing from the aging tank (5) enters the light component separation tower system (6); Step 6. The methanol vapor from the vapor-liquid separation tank (3), the dimethyl carbonate vapor generated by the reaction, and the mature liquid from the mature tank (5) are continuously fed into the light component separation tower system (6). The light component vapor separated by the light component separation tower system (6) is condensed by the condenser (6-3) and fed into the light component receiving tank (6-4). Part of the light component liquid separated by the light component separation tower system (6) is used as the reflux of the light component separation tower system (6), and part of it is fed into the methanol distillation tower system (7). The bottom liquid of the light component separation tower system (6) is continuously fed into the ethylene glycol distillation tower system (9) through the bottom pump of the separation tower. Step 7. The light component liquid from the light component separation tower system (6) and the azeotropic liquid from the azeotropic liquid receiving tank 8-4 of the dimethyl carbonate distillation tower continuously enter the methanol distillation tower system (7). The azeotropic vapor separated from the top of the methanol distillation tower system (7) is condensed by the methanol distillation tower condenser (7-3) and enters the azeotropic liquid receiving tank (7-4) to obtain an azeotropic liquid, part of which is used as the reflux of the methanol distillation tower system (7), and part of which enters the dimethyl carbonate distillation tower system (8); the bottom liquid of the methanol distillation tower system (7) enters the methanol vaporizer (7-6) through the methanol distillation tower bottom pump (7-7), and the vaporized methanol is further used for the transesterification reaction; Step 8. The azeotropic liquid from the azeotropic liquid receiving tank (7-4) of the methanol distillation tower system (7) continuously enters the dimethyl carbonate distillation tower system (8); the azeotropic product vapor separated from the top of the dimethyl carbonate distillation tower system (8) is condensed by the dimethyl carbonate distillation tower condenser (8-3) and enters the azeotropic liquid receiving tank (8-4) of the dimethyl carbonate distillation tower to obtain azeotropic liquid, part of which is used as reflux of the dimethyl carbonate distillation tower system (8), and part of which is returned to the methanol distillation tower system (7) as feed; the bottom liquid of the dimethyl carbonate distillation tower system (8) enters the dimethyl carbonate storage tank (8-6) through the dimethyl carbonate distillation tower bottom pump (8-7); Step 9. The bottom liquid from the light component separation tower system (6) continuously enters the ethylene glycol distillation tower system (9). The ethylene glycol vapor separated from the top of the ethylene glycol distillation tower system (9) is condensed by the ethylene glycol distillation tower condenser (9-3) and enters the ethylene glycol receiving tank (9-4) to obtain ethylene glycol, part of which is used as reflux of the ethylene glycol distillation tower system (9), and part of which is fed into the ethylene glycol storage tank (9-6). The bottom liquid of the ethylene glycol distillation tower system (9) is partially fed into the ethylene glycol distillation tower reboiler (9-1) through the ethylene glycol distillation tower bottom pump (9-7) to be heated and then returned to the ethylene glycol distillation tower system (9), and part of which is continuously fed into the batching tank (1) as a recovered catalyst. 8. The method for preparing dimethyl carbonate by using a high-speed jet impinging tubular reactor according to claim 7, characterized in that: In step 1, the temperature in the batching tank (1) is 70°C to 75°C, the pressure is normal pressure, and the residence time of the material is 0.5h to 0.75h; In step 2, the temperature inside the first high-speed jet impact tubular reactor (2) is 80° C. to 85° C., and the pressure is 0.2 MPa to 0.25 MPa; In step 3, the temperature in the vapor-liquid separation tank (3) is 70°C to 75°C, the pressure is normal pressure, and the residence time of the material is 0.5h to 0.75h; In step 4, the temperature in the second high-speed jet impact tubular reactor (4) is 80°C to 85°C, and the pressure is 0.2MPa to 0.25MPa: In step 5, the temperature in the maturation tank (5) is 80°C to 85°C, the pressure is 0.2MPa to 0.25MPa, and the residence time of the material is 1.5h to 2h; In step 6, the bottom temperature of the light component separation tower system (6) is 75°C to 78°C, the top temperature is 64°C to 66°C, the reflux ratio is 3 to 4, and the pressure is normal pressure; In step 7, the bottom temperature of the methanol distillation tower system (7) is 70°C, the bottom pressure is 0.13 MPa; the top temperature is 64°C, the top pressure is atmospheric pressure, and the reflux ratio is 2; In step 8, the dimethyl carbonate distillation tower system (8) has a bottom temperature of 183°C, a bottom pressure of 1.33 MPa, a top temperature of 147°C, a top pressure of 1.30 MPa, and a reflux ratio of 1.2; In step 9, the top temperature of the ethylene glycol distillation tower system (9) is 150°C, the top pressure is 0.02 MPa, the bottom temperature is 178°C, and the reflux ratio is 1.5.