阅读说明：本技术 一种含隔壁塔的能量耦合精制碳酸二甲酯的装置和工艺 (Device and process for refining dimethyl carbonate by energy coupling with partition wall tower ) 是由 聂明成 余海清 苗卉 于 2020-08-17 设计创作，主要内容包括：本发明公开了一种含隔壁塔的能量耦合精制碳酸二甲酯的装置和工艺。该装置包括常压共沸塔系统、加压共沸塔系统和DMC精制塔系统。通过采用系统内能量耦合和隔壁塔的使用,该装置及方法可从合成气制乙二醇的副产物粗碳酸二甲酯中获得精制碳酸二甲酯产品,能够有效去除粗碳酸二甲酯中的轻、重组分,得到高纯碳酸二甲酯产品。与传统分离工艺相比,该装置及方法可以大大降低能耗、减少设备投资、降低操作成本和节省占地。(The invention discloses a device and a process for refining dimethyl carbonate by energy coupling of a partition wall-containing tower. The device comprises an atmospheric azeotropic tower system, a pressurized azeotropic tower system and a DMC refining tower system. By adopting energy coupling in the system and the use of a partition wall tower, the device and the method can obtain a refined dimethyl carbonate product from the byproduct crude dimethyl carbonate of the preparation of ethylene glycol from the synthesis gas, and can effectively remove light and heavy components in the crude dimethyl carbonate to obtain a high-purity dimethyl carbonate product. Compared with the traditional separation process, the device and the method can greatly reduce energy consumption, equipment investment, operation cost and occupied land.)

1. A device and a process for refining dimethyl carbonate by energy coupling containing a partition wall tower are characterized in that: the method comprises an atmospheric azeotropic tower (T001), a pressurized azeotropic tower (T002) and a DMC refining tower (T003), wherein in the atmospheric azeotropic tower (T001), crude dimethyl carbonate containing methanol, light components and heavy components enters the atmospheric azeotropic tower (T001) from a filler at the lower part of a tower body, a product at the top of the pressurized azeotropic tower (T002) enters the atmospheric azeotropic tower (T001) from a filler at the upper part, and is rectified and separated, the methanol is extracted from the bottom of the atmospheric azeotropic tower (T001), the light components are extracted from the top of the atmospheric azeotropic tower (T001), an azeotrope of the methanol and the dimethyl carbonate is extracted from a side line of the tower, and the heat of a reboiler of the atmospheric azeotropic tower (T001) system is provided by the condensation of steam at the top of the pressurized azeotropic tower (T002);

in the pressurizing azeotropic tower (T002), the azeotrope of methanol and dimethyl carbonate enters the pressurizing azeotropic tower (T002) from the middle filler of the tower body, the product on the top of the DMC refining tower (T003) enters the pressurizing azeotropic tower (T002) from the middle filler, and is rectified and separated, the azeotrope of methanol and dimethyl carbonate is extracted from the top of the pressurizing azeotropic tower (T002), and the dimethyl carbonate containing trace methanol is extracted from the bottom of the pressurizing azeotropic tower (T002);

in the DMC refining tower (T003), the DMC refining tower (T003) is a partition plate tower, dimethyl carbonate containing trace methanol enters the DMC refining tower (T003) from the middle part, and after separation, a high-purity dimethyl carbonate product is extracted from the side line of the DMC refining tower (T003), dimethyl carbonate containing trace heavy components is extracted from the kettle of the DMC refining tower (T003), and dimethyl carbonate containing trace methanol is extracted from the top of the DMC refining tower (T003);

the number of theoretical plates of the normal-pressure azeotropic tower (T001) is 20-60; the number of theoretical plates of the pressurized azeotropic tower (T002) is 20-80; the number of theoretical plates of the DMC refining tower (T003) is 20-80.

2. The apparatus and process for refining dimethyl carbonate by energy coupling comprising a dividing wall column as claimed in claim 1, wherein: the method for refining the crude dimethyl carbonate containing methanol, light components and heavy components by using the device comprises the following steps:

1) introducing the crude dimethyl carbonate into a normal-pressure azeotropic tower (T001), separating by using the normal-pressure azeotropic tower (T001), wherein the product methanol is at the tower bottom, the light component is at the tower top, and the azeotrope of methanol and dimethyl carbonate is at the tower side line;

2) introducing an azeotrope of methanol and dimethyl carbonate into a pressurized azeotropic tower (T002), and performing rectification separation to obtain an azeotrope of methanol and dimethyl carbonate at the tower top and dimethyl carbonate containing trace methanol at the tower bottom;

3) introducing dimethyl carbonate containing trace methanol into a DMC refining tower (T003), and separating to obtain high-purity dimethyl carbonate as a side line product and heavy components in a tower kettle;

during the purification, the pressure at the top of the atmospheric azeotropic column (T001) was 150kPaA, the pressure at the top of the pressurized azeotropic column (T002) was 850kPaA, and the pressure at the top of the DMC purification column (T003) was 160 kPaA.

Technical Field

The invention relates to a device and a process for refining dimethyl carbonate by energy coupling of a partition wall-containing tower, in particular to a device and a process for refining crude dimethyl carbonate containing methanol, light components and heavy components by using an energy coupling rectification system of the partition wall-containing tower and obtaining a high-purity dimethyl carbonate product.

Background

In the technology for preparing ethylene glycol from synthesis gas used in China at present, methanol is required to participate in the reaction and generate a certain amount of byproduct dimethyl carbonate. In the DMC industrial separation process, because methanol and DMC form a binary azeotrope, the method is difficult to realize by adopting a common rectification method, and has the defects of large investment and high energy consumption.

CN107400055A discloses a battery-grade dimethyl carbonate rectification and purification method and equipment, and provides the battery-grade dimethyl carbonate rectification and purification method and equipment, which comprise two rectification towers, namely a normal-pressure bulkhead rectification tower, a low-pressure bulkhead rectification tower and the like. The heat integration operation is carried out between the normal pressure bulkhead rectifying tower and the low pressure bulkhead rectifying tower, and the gas phase at the top of the normal pressure bulkhead rectifying tower provides the energy required by the separation for the low pressure bulkhead rectifying tower. The low-pressure bulkhead rectifying tower for extracting the dimethyl carbonate product by the purification method is operated in high vacuum, the temperature of the top of the tower is very low (25-33 ℃), a large amount of low-temperature water is consumed as a condensing medium, and the operation cost is very high.

CN1271721A discloses a method for separating methanol and dimethyl carbonate azeotrope under pressure, which comprises two rectifying towers, namely a pressure rectifying tower and an atmospheric pressure rectifying tower, wherein the pressure rectifying tower and the atmospheric pressure rectifying tower are subjected to heat integration operation, and the gas phase at the top of the pressure rectifying tower provides energy required by separation for the atmospheric pressure rectifying tower. The method has the advantages of low yield of dimethyl carbonate, high operating pressure of the pressurized rectifying tower up to 1.8MPa, high operating temperature, high equipment safety level and high investment.

With the rapid promotion of the domestic project for preparing ethylene glycol from large coal, the purification and comprehensive utilization of the byproduct dimethyl carbonate become more and more important, and the search for a separation technology with low investment and low energy consumption is urgent.

The bulkhead rectifying tower is also called a clapboard rectifying tower, integrates two traditional rectifying towers in one tower body, and separates and rectifies raw materials in the tower by arranging the vertical clapboard inside the tower, so that the radial mixing of gas-liquid phase fluid is avoided, the back mixing is reduced, and the thermodynamic efficiency is improved. The bulkhead rectifying tower can reduce the equipment investment and save the cost; meanwhile, compared with the common rectifying tower, the bulkhead rectifying tower can reduce the energy consumption and save the equipment investment by about 40 percent.

Disclosure of Invention

The invention aims to provide a device and a process for refining dimethyl carbonate by energy coupling, which contain a partition wall tower, so as to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme: a device and process for refining dimethyl carbonate by energy coupling containing a partition wall tower comprise an atmospheric azeotropic tower, a pressurized azeotropic tower and a DMC refining tower, wherein in the atmospheric azeotropic tower, crude dimethyl carbonate containing methanol, light components and heavy components enters the atmospheric azeotropic tower from a filler at the lower part of a tower body, a product at the top of the pressurized azeotropic tower enters the atmospheric azeotropic tower from a filler at the upper part, the methanol is extracted from the bottom of the atmospheric azeotropic tower through rectification separation, the light components are extracted from the top of the atmospheric azeotropic tower, an azeotrope of the methanol and the dimethyl carbonate is extracted from a side line of the tower, and the heat of a reboiler of an atmospheric azeotropic tower system is provided by steam condensation at the top of the pressurized azeotropic tower;

in the pressurizing azeotropic tower, an azeotrope of methanol and dimethyl carbonate enters the pressurizing azeotropic tower from a middle filler of the tower body, a product at the top of the DMC refining tower enters the pressurizing azeotropic tower from the middle filler, and is rectified and separated, the azeotrope of the methanol and the dimethyl carbonate is extracted from the top of the pressurizing azeotropic tower, and the dimethyl carbonate containing trace methanol is extracted from the bottom of the pressurizing azeotropic tower;

in the DMC refining tower, the DMC refining tower is a partition plate tower, dimethyl carbonate containing trace methanol enters the DMC refining tower from the middle part, and after separation, a high-purity dimethyl carbonate product is extracted from the side line of the DMC refining tower, dimethyl carbonate containing trace heavy components is extracted from the bottom of the DMC refining tower, and dimethyl carbonate containing trace methanol is extracted from the top of the DMC refining tower;

the number of theoretical plates of the normal-pressure azeotropic tower is 20-60; the number of theoretical plates of the pressurizing azeotropic tower is 20-80; the number of the DMC refining tower theoretical plates is 20-80.

Preferably, the method for refining the crude dimethyl carbonate containing methanol, light components and heavy components by using the device comprises the following steps:

1) introducing crude dimethyl carbonate into a normal-pressure azeotropic tower, separating by the normal-pressure azeotropic tower, taking methanol as a product at the tower bottom, taking a light component at the tower top, and taking an azeotrope of methanol and dimethyl carbonate at the tower side line;

2) introducing an azeotrope of methanol and dimethyl carbonate into a pressurized azeotropic tower, and performing rectification separation to obtain the azeotrope of methanol and dimethyl carbonate at the tower top and the dimethyl carbonate containing trace methanol at the tower bottom;

3) introducing dimethyl carbonate containing trace methanol into a DMC refining tower, and separating to obtain high-purity dimethyl carbonate as a side product of the tower and heavy components contained in a tower kettle;

in the refining process, the tower top pressure of the normal-pressure azeotropic tower is 80-300 kPaA, the tower top pressure of the pressurizing azeotropic tower is 600-1200 kPaA, and the tower top pressure of the DMC refining tower is 80-300 kPaA.

Compared with the prior art, the invention has the beneficial effects that: the dividing wall tower can simplify the process and reduce the investment. Because the dividing wall tower is adopted to refine DMC, part of the material does not need to be repeatedly evaporated and condensed, but the material is directly subjected to gas-liquid mass transfer and energy exchange in the tower through reasonable control, so that the two-tower process flow of separating dimethyl carbonate containing trace methanol and then separating heavy components when the traditional rectification method is adopted is avoided, namely, the separation effect of combining two towers is realized by adopting one dividing wall tower, and the process flow is simplified. By reducing a rectifying tower, a set of condensing system and corresponding material delivery pump, a set of reboiling system and corresponding material delivery pump, the effects of saving occupied space, reducing equipment cost and saving energy are achieved. The dividing wall column is thermodynamically equivalent to a thermally coupled rectification column system. The use of the partition wall tower avoids energy waste caused by back mixing of dimethyl carbonate in the tower during separation, and realizes the energy-saving effect while ensuring the separation efficiency.

Drawings

FIG. 1 is a schematic view of the structure of the present invention.

In the figure: t001 atmospheric pressure azeotropic tower, T002 pressure azeotropic tower, T003 DMC refining tower.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, the present invention provides a technical solution: a device and process for refining dimethyl carbonate by energy coupling containing a partition wall tower comprise an atmospheric azeotropic tower, a pressurized azeotropic tower and a DMC refining tower, wherein in the atmospheric azeotropic tower, crude dimethyl carbonate containing methanol, light components and heavy components enters the atmospheric azeotropic tower from a filler at the lower part of a tower body, a product at the top of the pressurized azeotropic tower enters the atmospheric azeotropic tower from a filler at the upper part, the methanol is extracted from the bottom of the atmospheric azeotropic tower through rectification separation, the light components are extracted from the top of the atmospheric azeotropic tower, an azeotrope of the methanol and the dimethyl carbonate is extracted from a side line of the tower, and the heat of a reboiler of an atmospheric azeotropic tower system is provided by steam condensation at the top of the pressurized azeotropic tower;

in the pressurizing azeotropic tower, an azeotrope of methanol and dimethyl carbonate enters the pressurizing azeotropic tower from a middle filler of the tower body, a product at the top of the DMC refining tower enters the pressurizing azeotropic tower from the middle filler, and is rectified and separated, the azeotrope of the methanol and the dimethyl carbonate is extracted from the top of the pressurizing azeotropic tower, and the dimethyl carbonate containing trace methanol is extracted from the bottom of the pressurizing azeotropic tower;

in the DMC refining tower, the DMC refining tower is a partition plate tower, dimethyl carbonate containing trace methanol enters the DMC refining tower from the middle part, and after separation, a high-purity dimethyl carbonate product is extracted from the side line of the DMC refining tower, dimethyl carbonate containing trace heavy components is extracted from the bottom of the DMC refining tower, and dimethyl carbonate containing trace methanol is extracted from the top of the DMC refining tower.

Crude dimethyl carbonate containing methanol, light components and heavy components enters the normal pressure azeotropic tower T001 from a filler at the lower part of the tower body through a channel 001, and an azeotrope of the methanol and the dimethyl carbonate (with high methanol content) at the top of the pressurized azeotropic tower T002 enters the normal pressure azeotropic tower T001 from a filler at the upper part through a channel 007. After rectification separation, methanol is extracted from the bottom of the atmospheric azeotropic tower T001 through a channel 003, light components are extracted from the top of the atmospheric azeotropic tower T001 through a channel 002, and an azeotrope of methanol and dimethyl carbonate (with low methanol content) is extracted from the side line of the tower through a channel 006. The heat of the reboiler of the normal pressure azeotropic tower T001 system is provided by the condensation of the overhead vapor of the pressurized azeotropic tower T002.

The azeotrope of methanol and dimethyl carbonate (with low methanol content) enters the pressurizing azeotropic tower T002 through the channel 006 from the middle filler of the tower body, and the dimethyl carbonate containing trace methanol at the top of the DMC refining tower T003 enters the pressurizing azeotropic tower T002 through the channel 009 from the middle filler. After rectification separation, the azeotrope of methanol and dimethyl carbonate (high methanol content) is extracted from the top of the pressurizing azeotropic tower T002 through the channel 007, and the dimethyl carbonate containing a trace amount of methanol is extracted from the bottom of the pressurizing azeotropic tower T002 through the channel 008.

Dimethyl carbonate containing trace methanol enters a DMC refining tower T003 from the middle part through a channel 008, a high-purity dimethyl carbonate product is extracted from the side line of the DMC refining tower T003 through a channel 009 after separation, the dimethyl carbonate containing trace heavy components is extracted from the kettle of the DMC refining tower T003 through a channel 005, and the dimethyl carbonate containing trace methanol is extracted from the top of the DMC refining tower T003.

The number of theoretical plates of the normal-pressure azeotropic tower T001 is 20-60; the number of the T002 theoretical plates of the pressurized azeotropic tower is 20-80; the number of the DMC refining tower T003 theoretical plates is 20-80.

In the refining process, the top pressure of the normal-pressure azeotropic tower T001 is 80-300 kPaA, the top pressure of the pressurized azeotropic tower T002 is 600-1200 kPaA, and the top pressure of the DMC refining tower T003 is 80-300 kPaA.

In the method, the top temperature of the normal-pressure azeotropic tower T001 is 40-60 ℃, the top temperature of the pressurized azeotropic tower T002 is 100-150 ℃, and the top temperature of the DMC refining tower T003 is 90-120 ℃.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.