Energy-saving method for preparing electronic-grade carbonate

Abstract

The present disclosure discloses an energy-saving method for preparing electronic-grade carbonate, including the following steps that: industrial-grade dimethyl carbonate and anhydrous ethanol enter a reaction process after being preheated by a preheater, and are subjected to an esterification reaction under the action of a catalyst to obtain a mixture containing dimethyl carbonate, ethyl methyl carbonate and diethyl carbonate, and an azeotrope of dimethyl carbonate and methanol; the above-mentioned mixture enters a recovery process of dimethyl carbonate to recover unreacted dimethyl carbonate; a mixture of ethyl methyl carbonate and diethyl carbonate then enters a crude separation process to obtain crude ethyl methyl carbonate and crude diethyl carbonate; and the crude ethyl methyl carbonate is subjected to a refining process of ethyl methyl carbonate to obtain electronic-grade ethyl methyl carbonate, and the crude diethyl carbonate is subjected to a refining process of diethyl carbonate to obtain electronic-grade diethyl carbonate.

Claims

1. An energy-saving method for preparing electronic-grade carbonate, comprising a reaction process, a recovery process of dimethyl carbonate, a crude separation process, a refining process of ethyl methyl carbonate, a refining process of diethyl carbonate, and a refining process of dimethyl carbonate and methanol; wherein industrial-grade dimethyl carbonate and anhydrous ethanol enter the reaction process after being preheated by a preheater, and are subjected to an esterification reaction under the action of a catalyst to obtain a mixture containing dimethyl carbonate, ethyl methyl carbonate and diethyl carbonate, and an azeotrope of dimethyl carbonate and methanol; the mixture containing dimethyl carbonate, ethyl methyl carbonate and diethyl carbonate enters the recovery process of dimethyl carbonate to recover unreacted dimethyl carbonate; a mixture of ethyl methyl carbonate and diethyl carbonate then enters the crude separation process to obtain crude ethyl methyl carbonate and crude diethyl carbonate; the crude ethyl methyl carbonate is subjected to the refining process of ethyl methyl carbonate to obtain electronic-grade ethyl methyl carbonate, and the crude diethyl carbonate is subjected to the refining process of diethyl carbonate to obtain electronic-grade diethyl carbonate; the azeotrope of dimethyl carbonate and methanol is subjected to the refining process of dimethyl carbonate and methanol to obtain dimethyl carbonate and methanol; in the reaction process, industrial-grade dimethyl carbonate and ethanol enter an EMC reactive distillation column after being preheated by a pre-reactor, the EMC reactive distillation column is provided with a solid catalyst to catalyze the reaction, and a material discharged from the bottom of the EMC reactive distillation column enters a DMC recovery column; in the recovery process of dimethyl carbonate, a part of a material extracted from the top of the DMC recovery column is sent back to the EMC reactive distillation column, and the other part of the material extracted from the top of the DMC recovery column enters an anti-disproportionation reactor; DMC/EMC/DEC produced by the anti-disproportionation reactor is conveyed to the DMC recovery column; a material discharged from the bottom of the DMC recovery column enters a crude separation column; in the crude separation process, a material discharged from the top of the crude separation column enters an EMC light component removal column, and a material extracted from the bottom of the crude separation column enters a DEC light component removal column; in the refining process of ethyl methyl carbonate, a material discharged from the top of the EMC light component removal column enters the DMC recovery column, a material discharged from the bottom of the EMC light component removal column enters an EMC heavy component removal column, a material extracted from the side of the EMC heavy component removal column is electronic-grade EMC, a material discharged from the bottom of the EMC heavy component removal column enters the crude separation column, and a material discharged from the top of the EMC heavy component removal column enters the EMC light component removal column; in the refining process of diethyl carbonate, a material extracted from the bottom of the DEC light component removal column enters a DEC heavy component removal column, a material extracted from the top of the DEC heavy component removal column is sent back to the DEC light component removal column, a material extracted from the bottom of the DEC heavy component removal column is a DEC high-boiling residue, a part of a material extracted from the side of the DEC heavy component removal column is an electronic-grade DEC product, and a part of the material extracted from the side of the DEC heavy component removal column is conveyed to the anti-disproportionation reactor; and in the refining process of dimethyl carbonate and methanol, a material discharged from the top of the EMC reactive distillation column, namely the azeotrope of DMC and methanol enters a pressurizing column, a material discharged from the top of the pressurizing column enters an atmospheric column, a material discharged from the bottom of the pressurizing column enters a DMC refining column, a material discharged from the DMC refining column is a DMC high-boiling residue, a material discharged from the top of the atmospheric column enters the pressurizing column, a material discharged from the bottom of the atmospheric column enters a methanol refining column, and a material extracted from the side of the methanol refining column is a methanol by-product.

2. The energy-saving method for preparing electronic-grade carbonate of claim 1, wherein the reaction process is thermally integrated and coupled with the refining process of dimethyl carbonate and methanol for energy saving, the recovery process of dimethyl carbonate is thermally integrated and coupled with the crude separation process for energy saving, the refining process of ethyl methyl carbonate uses thermal integration and coupling for energy saving, the refining process of dimethyl carbonate and methanol uses mechanical vapor recompression for energy saving, and the refining process of ethyl methyl carbonate uses mechanical vapor recompression for energy saving.

3. The energy-saving method for preparing electronic-grade carbonate of claim 2, wherein a gas phase at the top of the crude separation column provides a partial heat source for a reboiler of the DMC recovery column.

4. The energy-saving method for preparing electronic-grade carbonate of claim 2, wherein a gas phase at the top of the pressurizing column provides a partial heat source for a reboiler of the EMC reactive distillation column.

5. The energy-saving method for preparing electronic-grade carbonate of claim 2, wherein a gas phase at the top of the atmospheric column is converted into secondary steam under the action of a compressor of the atmospheric column to provide a heat source for a reboiler of the atmospheric column.

6. The energy-saving method for preparing electronic-grade carbonate of claim 2, wherein a gas phase at the top of the methanol refining column is converted into secondary steam under the action of a compressor of a methanol column to provide a heat source for a reboiler of the methanol refining column.

7. The energy-saving method for preparing electronic-grade carbonate of claim 2, wherein the mechanical vapor recompression for energy saving in the refining process of ethyl methyl carbonate comprises an EMC compressor, secondary steam compressed by the EMC compressor is delivered to a reboiler of the EMC light component removal column and a reboiler of the EMC heavy component removal column, respectively, and is heated, and then the heated material passes through the following two branches, respectively; a branch 1 where the steam is cooled into water after passing through the reboiler of the EMC light component removal column, and enters a condenser of the EMC light component removal column for heat exchange and partial vaporization, and the generated steam continues to enter the EMC compressor; a branch 2 where the steam is cooled into water after passing through the reboiler of the EMC heavy component removal column, and enters a condenser of the EMC heavy component removal column for heat exchange and partial vaporization, and the generated steam continues to enter the EMC compressor; and recycling is performed through the branch 1 and the branch 2.

8. The energy-saving method for preparing electronic-grade carbonate of claim 1, wherein operating parameters of the pre-reactor are as follows: an operating temperature is 110-130? C., and an operating pressure is 300-900 kPaA; operating parameters of the anti-disproportionation reactor are as follows: an operating temperature is 110-130? C., and an operating pressure is 300-900 kPaA; operating parameters of the EMC reactive distillation column are as follows: a column top temperature is 64? C., a column bottom temperature is 105? C., and an operating pressure is an atmospheric pressure; operating parameters of the DMC recovery column are as follows: a column top temperature is 50?55? C., a column bottom temperature is 75?80? C., an operating pressure is 25?40 kPaA, a reflux ratio is 5?10, the number of theoretical plates is 30?60, and feed positions are at 10?30th theoretical plates; operating parameters of the crude separation column are as follows: a column top temperature is 101?150? C., a column bottom temperature is 128?135? C., an operating pressure is 90?200 kPaA, a reflux ratio is 1?10, the number of theoretical plates is 30?60, and feed positions are at 10?30th theoretical plates; operating parameters of the EMC light component removal column are as follows: a column top temperature is 50?60? C., a column bottom temperature is 70?80? C., an operating pressure is 20?30 kPaA, a reflux feed ratio is 1?5, the number of theoretical plates is 50?60, and feed positions are at 10?30th theoretical plates; operating parameters of the EMC heavy component removal column are as follows: a column top temperature is 50?60? C., a column bottom temperature is 70?80? C., an operating pressure is 20?30 kPaA, a reflux feed ratio is 1?5, the number of theoretical plates is 50?60, and feed positions are at 40?50th theoretical plates; operating parameters of the DEC light component removal column are as follows: a column top temperature is 50?60? C., a column bottom temperature is 128?150? C., an operating pressure is 101?200 kPaA, the number of theoretical plates is 50?60, and feed positions are at 10?30th theoretical plates; operating parameters of the DEC heavy component removal column are as follows: a column top temperature is 85-90? C., a column bottom temperature is 90?100? C., a reflux feed ratio is 1?5, the number of theoretical plates is 50?60, feed positions are at 40?50th theoretical plates, and side extraction is performed at a 20th theoretical plate; operating parameters of the pressurizing column are as follows: a column top temperature is 170-190? C., a column bottom temperature is 700-1000? C., a reflux feed ratio is 1?5, the number of theoretical plates is 50?60, and feed positions are at 30?50th theoretical plates; operating parameters of the atmospheric column are as follows: a column top temperature is 64? C., a column bottom temperature is 66? C., an operating pressure is 101?110 kPaA, a reflux feed ratio is 1?5, the number of theoretical plates is 50?60, and feed positions are at 30?50th theoretical plates; operating parameters of the DMC refining column are as follows: a column top temperature is 91? C., a column bottom temperature is 94? C., an operating pressure is 101?110 kPaA, a reflux feed ratio is 1?5, the number of theoretical plates is 50?60, feed positions are at 30?50th theoretical plates, and side extraction is performed at a 20th theoretical plate; and operating parameters of the methanol refining column are as follows: a column top temperature is 64? C., a column bottom temperature is 66? C., an operating pressure is 101?110 kPaA, a reflux feed ratio is 1?5, the number of theoretical plates is 50?60, feed positions are at 30?50th theoretical plates, and side extraction is performed at a 20th theoretical plate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram of a preparation process in Example 1 of the present disclosure.

(2) FIG. 2 is a diagram of a system in Example 2 of the present disclosure.

(3) FIG. 3 is a diagram of a system in Example 3 of the present disclosure.

(4) 1Pre-reactor, 2EMC reactive distillation column, 3DMC recovery column, 4anti-disproportionation reactor, 5crude separation column, 6EMC light component removal column, 7EMC heavy component removal column, 8DEC light component removal column, 9DEC heavy component removal column, 10pressurizing column, 11atmospheric column, 12methanol refining column, 13DMC refining column, 14industrial-grade dimethyl carbonate feeding pipeline, 15ethanol feeding pipeline, 16first connection pipeline, 17second connection pipeline, 18column top gas phase pipeline, 19reboiler of DMC recovery column, 20DEC high-boiling residue discharge pipeline, 21EMC side extraction outlet, 22electronic-grade DEC product output pipeline, 23reboiler of EMC reactive distillation column, 24DMC high-boiling residue discharge pipeline, 25compressor of atmospheric column, 26EMC compressor, 27methanol by-product discharge pipeline, 28reboiler of DEC heavy component removal column, 29reboiler of methanol refining column, 30compressor of methanol column, 31gas-liquid separation tank, 32first branch pipe, 33second branch pipe, 34reboiler of EMC light component removal column, 35reboiler of EMC heavy component removal column, 36reboiler of atmospheric column, 37condenser of EMC heavy component removal column, 38condenser of EMC light component removal column.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(5) The present disclosure is described in further detail below in connection with specific examples. It should be understood that the specific examples described herein are intended to explain the present disclosure only and are not intended to limit the present disclosure.

Example 1

(6) As shown in FIG. 1, an energy-saving method for preparing electronic-grade carbonate includes a reaction process, a recovery process of dimethyl carbonate, a crude separation process, a refining process of ethyl methyl carbonate, a refining process of diethyl carbonate, and a refining process of dimethyl carbonate and methanol; industrial-grade dimethyl carbonate and anhydrous ethanol enter the reaction process after being preheated by a preheater, and are subjected to esterification reaction under the action of a catalyst to obtain a mixture containing dimethyl carbonate, ethyl methyl carbonate and diethyl carbonate, and an azeotrope of dimethyl carbonate and methanol; the mixture containing dimethyl carbonate, ethyl methyl carbonate and diethyl carbonate enters the recovery process of dimethyl carbonate to recover unreacted dimethyl carbonate; a mixture of ethyl methyl carbonate and diethyl carbonate then enters the crude separation process to obtain crude ethyl methyl carbonate and crude diethyl carbonate; the crude ethyl methyl carbonate is subjected to the refining process of ethyl methyl carbonate to obtain electronic-grade ethyl methyl carbonate, and the crude diethyl carbonate is subjected to the refining process of diethyl carbonate to obtain electronic-grade diethyl carbonate; and the azeotrope of dimethyl carbonate and methanol is subjected to the refining process of dimethyl carbonate and methanol to obtain dimethyl carbonate and methanol.

(7) Wherein the reaction process is thermally integrated and coupled with the refining process of dimethyl carbonate and methanol for energy saving, the recovery process of dimethyl carbonate is thermally integrated and coupled with the crude separation process for energy saving, the refining process of ethyl methyl carbonate uses thermal integration and coupling for energy saving, the refining process of dimethyl carbonate and methanol uses mechanical vapor recompression for energy saving, and the refining process of ethyl methyl carbonate uses mechanical vapor recompression for energy saving.

Example 2

(8) As shown in FIG. 2, this example provides further detailed descriptions of equipment for each process based on Example 1.

(9) The reaction process includes a pre-reactor 1 and an EMC reactive distillation column 2; the recovery process of dimethyl carbonate includes a DMC recovery column 3; the crude separation process includes a crude separation column 5; the refining process of ethyl methyl carbonate includes an EMC light component removal column 6 and an EMC heavy component removal column 7; the refining process of diethyl carbonate includes a DEC light component removal column 8 and a DEC heavy component removal column 9; the refining process of dimethyl carbonate and methanol includes a pressurizing column 10, an atmospheric column 11, a methanol refining column 12 and a DMC refining column 13; industrial-grade dimethyl carbonate and anhydrous ethanol enter the pre-reactor 1 after being preheated by a preheater for a reaction, and the resulting reaction solution then enters the EMC reactive distillation column 2, and the EMC reactive distillation column 2 is provided with a catalytic filler containing a solid catalyst in a lower middle part, with no subsequent catalyst separation process, and preferably, a main component of the solid catalyst is silica, and the solid catalyst is fixed in the reactor by a certain support means, the solid catalyst and regular corrugated sheets are effectively combined together to form a plurality of catalyst fillers having a hollow structure, and a material discharged from the bottom of the EMC reactive distillation column 2 enters the DMC recovery column 3; a part of a material extracted from the top of the DMC recovery column 3 is sent back to the pre-reactor 1 to continue to react with ethanol, and the other part of the material extracted from the top of the DMC recovery column 3 enters the anti-disproportionation reactor 4 to react with dimethyl carbonate to generate ethyl methyl carbonate; mixed esters (dimethyl carbonate, ethyl methyl carbonate and diethyl carbonate) produced by the anti-disproportionation reactor 4 are conveyed to the DMC recovery column 3 to recover unreacted dimethyl carbonate; a material discharged from the bottom of the DMC recovery column 3 enters the crude separation column 5, a gas phase at the top of the crude separation column 5 provides a partial heat source for a reboiler 19 of the DMC recovery column; a material discharged from the top of the crude separation column 5 enters the EMC light component removal column 6, a material discharged from the top of the EMC light component removal column 6 enters the DMC recovery column 3, a material discharged from the bottom of the EMC light component removal column 6 enters the EMC heavy component removal column 7, a material extracted from the side of the EMC heavy component removal column 7 is electronic-grade EMC (by means of side extraction, light and heavy components can be removed in one column, trace light components are accumulated at the top of the column, heavy components are extracted from the bottom of the column and qualified products are obtained by side extraction), a material discharged from the bottom of the EMC heavy component removal column 7 enters the crude separation column 5, and a material discharged from the top of the EMC heavy component removal column 7 enters the EMC light component removal column 6; a material extracted from the bottom of the crude separation column 5 enters the DEC light component removal column 8, a material extracted from the top of the DEC light component removal column 8 enters the crude separation column 5; a material extracted from the bottom of the DEC light component removal column 8 enters the DEC heavy component removal column 9, a material extracted from the top of the DEC heavy component removal column 9 is sent back to the DEC light component removal column 8, a material extracted from the bottom of the DEC heavy component removal column 9 is a DEC high-boiling residue, a part of a material extracted from the side of the DEC heavy component removal column 9 is an electronic-grade DEC product, and a part of the material extracted from the side of the DEC heavy component removal column 9 is conveyed to the anti-disproportionation reactor 4, and a gas phase at the top of the DEC light component removal column 8 provides a partial heat source for a reboiler 28 of the DEC heavy component removal column; and a material discharged from the top of the EMC reactive distillation column 2, namely the azeotrope of DMC and methanol enters the pressurizing column 10, a gas phase at the top of the pressurizing column 10 provides a partial heat source for a reboiler 23 of the EMC reactive distillation column, a material discharged from the top of the pressurizing column 10 enters the atmospheric column 11, a material discharged from the bottom of the pressurizing column 10 enters the DMC refining column 13, a material discharged from the bottom of the DMC refining column 13 is a DMC high-boiling residue, a material discharged from the top of the DMC refining column 13 enters the pressurizing column 10, a material extracted from the side of the DMC refining column 13 is industrial-grade DMC, a side extraction outlet of the DMC refining column 13 communicates with the pre-reactor 1, a material discharged from the top of the atmospheric column 11 enters the pressurizing column 10, a gas phase at the top of the atmospheric column 11 is converted into secondary steam under the action of a compressor 25 of the atmospheric column to provide a heat source for a reboiler 36 of the atmospheric column, a material discharged from the bottom of the atmospheric column 11 enters the methanol refining column 12, a gas phase at the top of the methanol refining column 12 is converted into secondary steam under the action of a compressor 30 of a methanol column to provide a heat source for a reboiler 29 of the methanol refining column, a material extracted from the side of the methanol refining column 12 is a methanol by-product, a material extracted from the top of the methanol refining column 12 enters the pressurizing column 10, and a material extracted from the bottom of the methanol refining column 12 is reboiled, and the material extracted from the bottom of the column enters a reboiling tank, and is discharged to the outside.

(10) The mechanical vapor recompression for energy saving in the refining process of ethyl methyl carbonate includes an EMC compressor 26, secondary steam compressed by the EMC compressor 26 is delivered to a reboiler 34 of the EMC light component removal column, and a reboiler 35 of the EMC heavy component removal column, respectively, and is heated, and then the heated material passes through the following two branches, respectively; a branch 1, where the steam is cooled into water after passing through the reboiler 34 of the EMC light component removal column, and enters a condenser 38 of the EMC light component removal column for heat exchange and partial vaporization, and the generated steam continues to enter the EMC compressor 26; a branch 2, where the steam is cooled into water after passing through the reboiler 35 of the EMC heavy component removal column, and enters a condenser 37 of the EMC heavy component removal column for heat exchange and partial vaporization, and the generated steam continues to enter the EMC compressor 26; and recycling is performed through the branch 1 and the branch 2.

Example 3

(11) An energy-saving system for preparing electronic-grade carbonate, as shown in FIG. 3, includes a pre-reactor 1, an EMC reactive distillation column 2, a DMC recovery column 3, an anti-disproportionation reactor 4, a crude separation column 5, an EMC light component removal column 6, an EMC heavy component removal column 7, a DEC light component removal column 8, a DEC heavy component removal column 9, a pressurizing column 10, an atmospheric column 11, a methanol refining column 12 and a DMC refining column 13; wherein the pre-reactor 1 is connected to an industrial-grade dimethyl carbonate feeding pipeline 14 and an ethanol feeding pipeline 15, a discharge port at the bottom of the pre-reactor 1 communicates with a feed port at the lower middle part of the EMC reactive distillation column 2 through a pipeline, and the EMC reactive distillation column 2 is provided with a catalytic filler containing a solid catalyst; a discharge port at the bottom of the EMC reactive distillation column 2 is connected via a pipeline to a feed inlet at the middle of the DMC recovery column 3; a top extraction outlet of the DMC recovery column 3 communicates with a feed inlet of a raw material DMC of the pre-reactor 1 via a first connection pipeline 16, and the top extraction outlet of the DMC recovery column 3 communicates with a feed inlet of a raw material DMC of the anti-disproportionation reactor 4 via a second connection pipeline 17; and a discharge port of mixed esters (dimethyl carbonate, ethyl methyl carbonate and diethyl carbonate) at the bottom of the anti-disproportionation reactor 4 communicates with a feed inlet at the lower part of the DMC recovery column 3 via a pipeline; a discharge port at the bottom of the DMC recovery column 3 communicates with a feed inlet at the middle of the crude separation column 5 via a pipeline, a column top gas phase pipeline 18 of the crude separation column 5 is subjected to heat exchange with the reboiler 19 of the DMC recovery column, and a liquid phase port at the lower part of the reboiler 19 of the DMC recovery column is connected to an inlet of a reflux tank of the crude separation column 5; a discharge port at the top of the crude separation column 5 communicates with a feed inlet at the middle of the EMC light component removal column 6, a discharge port at the top of the EMC light component removal column 6 is connected to the feed inlet at the middle of the DMC recovery column 3, a discharge port at the bottom of the EMC light component removal column 6 is connected to a feed inlet at the middle of the EMC heavy component removal column 7, a distillation section of the EMC heavy component removal column 7 is provided with an electronic-grade EMC side extraction outlet 21 for extraction of electronic-grade EMC, and a discharge port at the bottom of the EMC heavy component removal column 7 communicates with the feed inlet at the middle of the crude separation column 5; a discharge port at the bottom of the crude separation column 5 communicates with a feed inlet at the upper part of the DEC light component removal column 8 via a pipeline, a bottom extraction outlet of the DEC light component removal column 8 communicates with a feed inlet at the middle of the DEC heavy component removal column 9, a top extraction outlet of the DEC heavy component removal column 9 communicates with a feed inlet at the upper part of the DEC light component removal column 8, a bottom extraction outlet of the DEC heavy component removal column 9 is connected with a DEC high-boiling residue discharge pipeline 20, a side extraction outlet of the DEC heavy component removal column 9 is connected to an electronic-grade DEC product output pipeline 22, the electronic-grade DEC product output pipeline 22 is also connected to a pipeline of a raw material DEC of the anti-disproportionation reactor 4 through a pipeline, a gas phase pipeline at the top of the DEC light component removal column 8 is subjected to heat exchange with the reboiler 28 of the DEC heavy component removal column, and a liquid phase port at lower part of the reboiler 28 of the DEC heavy component removal column is connected to an inlet of a reflux tank of the DEC light component removal column 8; a discharge port at the top of the EMC reactive distillation column 2 is connected to a feed inlet at the middle of the pressurizing column 10 through a pipeline, a gas phase at the top of the pressurizing column 10 is connected to the reboiler 23 of the EMC reactive distillation column through a heat exchange pipeline, the reboiler 23 of the EMC reactive distillation column communicates with a feed inlet of the pressurizing column 10 and a feed inlet of the atmospheric column 11 through pipelines, respectively, a discharge port at the bottom of the pressurizing column 10 communicates with a feed inlet at the middle of the DMC refining column 13, a discharge port at the bottom of the DMC refining column 13 is connected to a DMC high-boiling residue discharge pipeline 24, a side extraction outlet of the DMC refining column 13 communicates with the pre-reactor 1, a gas phase outlet at the top of the atmospheric column 11 is connected to an inlet of the compressor 25 of the atmospheric column through a pipeline, an outlet of the compressor 25 of the atmospheric column is connected to the reboiler 36 of the atmospheric column, a part of the reboiler 36 of the atmospheric column is connected by a pipeline to a reflux port at the top of the atmospheric column 11 and a part is connected to a feed inlet at the middle-upper part of the pressurizing column 10; and a discharge part at the bottom of the atmospheric column 11 is connected to a feed inlet at the middle of the methanol refining column 12, a gas phase outlet at the top of the methanol refining column 12 communicates with an inlet of the compressor 30 of the methanol column via a pipeline, an outlet of the compressor 30 of the methanol column communicates with the reboiler 29 of the methanol refining column via a pipeline, the reboiler 29 of the methanol refining column communicates with the middle of the methanol refining column 12 and the middle of the atmospheric column 11 via pipelines, respectively, and a side extraction outlet of the methanol refining column 12 is connected to a methanol by-product discharge pipeline 27.

(12) The mechanical vapor recompression for energy saving in the refining process of ethyl methyl carbonate includes an EMC compressor 26 and a gas-liquid separation tank 31, a gas phase outlet of the gas-liquid separation tank 31 is connected to the EMC compressor 26, an outlet of the EMC compressor 26 is connected via a first branch pipe 32 to a heat exchange interlayer of the reboiler 35 of the EMC heavy component removal column, an outlet of the heat exchange interlayer of the reboiler 35 of the EMC heavy component removal column is connected to a water inlet of the gas-liquid separation tank 31, the outlet of the EMC compressor 26 is connected via a second branch pipe 33 to a heat exchange interlayer of the reboiler 34 of the EMC light component removal column, and an outlet of the heat exchange interlayer of the reboiler 34 of the EMC light component removal column, and the outlet of the heat exchange interlayer of the reboiler 35 of the EMC heavy component removal column are connected to the water inlet of the gas-liquid separation tank 31; and a water outletsof the gas-liquid separation tank 31 is connected to a water inlet of a heat exchange interlayer of the condenser 37 of the EMC heavy component removal column, and a water inlet of a heat exchange interlayer of the condenser 38 of the EMC light component removal column via pipelines, respectively, and a steam outlet of the heat exchange interlayer of the condenser 37 of the EMC heavy component removal column, and a steam outlet of the heat exchange interlayer of the condenser 38 of the EMC light component removal column are connected to a steam inlet of the gas-liquid separation tank 31 via pipelines, respectively.

Example 4

(13) This example provides a further description of operating parameters of each device based on Example 2.

(14) Operating parameters of the pre-reactor 1 are as follows:

(15) TABLE-US-00014 Optimal Parameter operating Name range parameter Operating temperature (? C.) 110-130 115 Operating pressure kPaA 300-900 400~500

(16) Operating parameters of the anti-disproportionation reactor 4 are as follows:

(17) TABLE-US-00015 Optimal Parameter operating Name range parameter Operating temperature (? C.) 110-130 115 Operating pressure kPaA 300-900 400~500

(18) Operating parameters of the EMC reactive distillation column 2 are as follows:

(19) TABLE-US-00016 Parameter Optimal operating Name range parameter Column top 64 / temperature (? C.) Column bottom 105 / temperature (? C.) Operating pressure atmospheric / kPaA pressure Reflux ratio 2~6 4 The number of 30~60 50 theoretical plates Feed position 30~50 40 Side extraction / /

(20) Operating parameters of the DMC recovery column 3 are as follows:

(21) TABLE-US-00017 Parameter Optimal operating Name range parameter Column top 50~55 52 temperature (? C.) Column bottom 75~80 77 temperature (? C.) Operating pressure 25~40 30 kPaA Reflux ratio 5~10 7 The number of 30~60 50 theoretical plates Feed position 10~30 20 Side extraction / /

(22) Operating parameters of the crude separation column 5 are as follows:

(23) TABLE-US-00018 Parameter Optimal operating Name range parameter Column top 101~150 106 temperature (? C.) Column bottom 128~135 130 temperature (? C.) Operating pressure 90~200 30 kPaA Reflux ratio 1~10 3 The number of 30~60 50 theoretical plates Feed position 10~30 20 Side extraction / /

(24) Operating parameters of the EMC light component removal column 6 are as follows:

(25) TABLE-US-00019 Parameter Optimal operating Name range parameter Column top 50~60 55 temperature (? C.) Column bottom 70~80 75 temperature (? C.) Operating pressure 20~30 25 kPaA Reflux feed ratio 1~5 3 The number of 50~60 50 theoretical plates Feed position 10~30 20 Side extraction / /

(26) Operating parameters of the EMC heavy component removal column 7 are as follows:

(27) TABLE-US-00020 Parameter Optimal operating Name range parameter Column top 50~60 55 temperature (? C.) Column bottom 70~80 75 temperature (? C.) Operating pressure 20~30 25 kPaA Reflux feed ratio 1~5 3 The number of 50~60 50 theoretical plates Feed position 40~50 45 Side extraction 20 /

(28) Operating parameters of the DEC light component removal column 8 are as follows:

(29) TABLE-US-00021 Parameter Optimal operating Name range parameter Column top 50~60 55 temperature (? C.) Column bottom 128~150 130 temperature (? C.) Operating pressure 101~200 105 kPaA Reflux feed ratio 1~5 3 The number of 50~60 50 theoretical plates Feed position 10~30 20 Side extraction / /

(30) Operating parameters of the DEC heavy component removal column 9 are as follows:

(31) TABLE-US-00022 Parameter Optimal operating Name range parameter Column top 85~90 88 temperature (? C.) Column bottom 90~100 95 temperature (? C.) Operating pressure 20~40 30 kPaA Reflux feed ratio 1~5 3 The number of 50~60 50 theoretical plates Feed position 40~50 45 Side extraction 20 /

(32) Operating parameters of the pressurizing column 10 are as follows:

(33) TABLE-US-00023 Parameter Optimal operating Name range parameter Column top 130~150 140 temperature (? C.) Column bottom 170~190 95 temperature (? C.) Operating pressure 700~1000 900 kPaA Reflux feed ratio 1~5 3 The number of 50~60 50 theoretical plates Feed position 30~50 40 Side extraction / /

(34) Operating parameters of the atmospheric column 11 are as follows:

(35) TABLE-US-00024 Parameter Optimal operating Name range parameter Column top 64 / temperature (? C.) Column bottom 66 / temperature (? C.) Operating pressure 101~110 105 kPaA Reflux feed ratio 1~5 3 The number of 50~60 50 theoretical plates Feed position 30~50 40 Side extraction / /

(36) Operating parameters of the DMC refining column 13 are as follows:

(37) TABLE-US-00025 Parameter Optimal operating Name range parameter Column top 91 / temperature (? C.) Column bottom 94 / temperature (? C.) Operating pressure 101~110 105 kPaA Reflux feed ratio 1~5 3 The number of 50~60 50 theoretical plates Feed position 30~50 40 Side extraction 20 /

(38) Operating parameters of the methanol refining column 12 are as follows:

(39) TABLE-US-00026 Parameter Optimal operating Name range parameter Column top 64 / temperature (? C.) Column bottom 66 / temperature (? C.) Operating pressure 101~110 105 kPaA Reflux feed ratio 1~5 3 The number of 50~60 50 theoretical plates Feed position 30~50 40 Side extraction 20 /

(40) The energy consumption of this example is shown in the following table:

(41) TABLE-US-00027 Energy consumption Power per ton of product (ton consumption (kW- Name of steam/ton of product h/ton of product) Example 4 3.237 210 Non-energy- 8.72 74 saving process

(42) Wherein a compression ratio of the EMC compressor is 2.4, and a compression ratio of the compressor of the atmospheric column is 1.45, and a compression ratio of the compressor of the methanol column is 1.45.

Comparative Example

Comparative Example 1.1

(43) Patent: CN112142599A Low-Energy-Consumption and Green Carbonate Product Production Process and System

(44) TABLE-US-00028 Energy consumption Power per ton of product (ton consumption (kW- Name of steam/ton of product h/ton of product) This patent 4.97 with a heat pump, and no consumption Non-energy- 10 / saving process

Comparative Example 1.2

(45) Patent: CN106699565A Device for energy saving of dimethyl carbonate device

(46) This device mainly consists of a reaction column, a pressurizing column and an atmospheric column, and produces dimethyl carbonate (non-electronic grade).

(47) TABLE-US-00029 Energy consumption Power per ton of product (ton consumption (kW- Name of steam/ton of product h/ton of product) This patent 2.25 209.5 Non-energy- 3.5 / saving process

Comparative Example 1.3

(48) Patent: CN110845334A Device and Method for Preparing Battery-Grade Ethyl Methyl Carbonate from Dimethyl Carbonate and Ethanol

(49) This device mainly consists of three columns: a reaction column, a diethyl carbonate removal column and an ethyl methyl carbonate refining column. Dimethyl carbonate and methanol are not separated, and there is no refining of diethyl carbonate.

(50) TABLE-US-00030 Energy consumption Power per ton of product (ton consumption (kW- Name of steam/ton of product h/ton of product) CN110845334A 5.2 100 Example 1 3 160 Example 2 2.9 168

(51) The above descriptions are only preferred embodiments of the present disclosure, and it should be noted that for a person of ordinary skill in the art, a number of improvements and modifications can also be made without departing from the principles of the present disclosure, and these improvements and modifications shall also be considered as the scope of protection of the present disclosure.