CN217312008U

CN217312008U - Acrylic acid purification device capable of recycling energy

Info

Publication number: CN217312008U
Application number: CN202220658743.8U
Authority: CN
Inventors: 陈浩
Original assignee: Shanghai Muji Industrial Co ltd
Current assignee: Shanghai Muji Industrial Co ltd
Priority date: 2022-03-23
Filing date: 2022-03-23
Publication date: 2022-08-30
Anticipated expiration: 2032-03-23

Abstract

An acrylic acid purification device with energy reuse, which takes water as a cooling medium, and exchanges heat with steam discharged from the top of a rectifying tower in a condenser, the water is heated, the water after heat exchange flows into the lower part of a storage tank, and the generated steam is guided into the upper part of the storage tank; after the water vapor is buffered at the upper part of the storage tank, the water vapor enters the MVR device and is pressurized and heated to form vapor which can be used by the reboiler, the MVR vapor discharged from the outlet of the MVR device and materials from the bottom of the rectifying tower exchange heat in the reboiler, and the MVR vapor forms MVR condensed water and flows into the storage tank again. The utility model discloses a method adopts MVR technique with steam and hydrologic cycle fluid medium, does not contact with organic material, does not use the refrigerant harmful to the environment, dangerous or corrosivity, has greatly reduced safety, and environmental protection risk has reduced the energy consumption by a wide margin.

Description

Acrylic acid purification device capable of recycling energy

Technical Field

The utility model relates to an apparatus for producing of energy recycling especially relates to a device of retrieving and recycling the energy in the acrylic acid production to improve energy utilization efficiency, reduce cost.

Background

At present, acrylic acid devices in China adopt a two-step oxidation method of propylene, under the existence of a composite metal oxide catalyst, acrolein is firstly generated through air oxidation, and then acrylic acid is further generated through catalytic oxidation. The acrylic acid generated after the two-step oxidation of the propylene is mainly subjected to absorption, rectification and other methods to finally produce acrylic acid products, the refining process adopted by each manufacturer can not be separated from rectification no matter which process is adopted, and the acrylic acid is usually purified by adopting more than 2 (including) rectification towers. In the acrylic acid industry, in all rectification processes, fresh steam is added into a reboiler at the bottom of a tower to heat materials in a rectification tower, and cooling media such as cooling water/circulating water are added into a condenser at the top of the tower to cool the materials.

For energy saving, CN105473541A discloses a method for continuously recovering (meth) acrylic acid, minimizing the loss of (meth) acrylic acid, especially in the distillation process, and making the distillation process operate stably and save energy. Contacting a mixed gas including (meth) acrylic acid, organic by-products, and steam generated by a synthesis reaction of (meth) acrylic acid with an absorption solvent including water in an absorption process to obtain an aqueous solution of (meth) acrylic acid; contacting a part of the aqueous (meth) acrylic acid solution obtained through the absorption process with an extraction solvent in an extraction column during extraction to obtain a (meth) acrylic acid extraction solution through an upper outlet of the extraction column and a raffinate solution passing through a lower stationary part of the extraction column through a lower outlet; and a remaining part of the aqueous (meth) acrylic acid solution obtained by the absorption process and a feed of the (meth) acrylic acid extract obtained by the extraction process in the distillation process to obtain (meth) acrylic acid.

CN1683309A discloses a process method for purifying (methyl) acrylic acid by combining extraction and azeotropic distillation, wherein the process flow comprises 4 towers of an extraction tower, a light component removal tower, a crude distillation tower and a refining tower; the (methyl) acrylic acid aqueous solution is divided into two parts, and one part directly enters a light component removing tower; one part of the water enters an extraction tower to be extracted with an organic solvent in a counter-current way, the bottom of the extraction tower is wastewater, and the (methyl) acrylic acid which is basically free of water and obtained at the top of the extraction tower enters a light component removal tower together with the solvent for azeotropic dehydration; one part of the tower top solvent phase of the light component removal tower, namely the azeotropic distillation dehydration tower, is used as the reflux of the tower top solvent phase, the other part of the tower top solvent phase is directly used as the extraction solvent of the (methyl) acrylic acid extraction part, and the azeotropic distillation dehydration and acetic acid removal part becomes one part of the solvent regeneration process of the extraction concentration part; the material at the tower bottom of the light component removal tower enters a crude distillation tower, and residual acetic acid and solvent are removed from the tower top of the crude distillation tower; the material at the bottom of the crude distillation tower enters a refining tower, and a (methyl) acrylic acid product is obtained at the top of the refining tower. One or a mixed compound which is hydrophobic and can form an azeotrope with water and acetic acid is used as a solvent and an azeotropic agent, the processes of (methyl) acrylic acid extraction concentration, dehydration, deacetic acid and (methyl) acrylic acid azeotropic rectification dehydration, deacetic acid and purification are organically integrated, the (methyl) acrylic acid extraction agent is combined with the azeotropic dehydration and the deacetic acid agent into a whole, and the (methyl) acrylic acid extraction agent and the azeotropic dehydrating agent are simultaneously used.

CN113198200A discloses an energy-saving method for a rectification system, which heats or boosts the gas phase at the top of a rectification tower to be used as a higher-order energy source after being heated, and then the gas phase returns to a reboiler to supply heat, so that the total energy consumption in the rectification process is reduced, the grade of a heat source is reduced, the thermodynamic efficiency of the whole tower is improved, and the operation cost is greatly reduced.

CN109879722A discloses a low concentration ethanol recovery device based on MVR, comprising a low concentration ethanol recovery device body provided with a falling film heat exchanger (2) connected with a rectifying tower (1) and a reboiler (8) connected with the rectifying tower (1), a separator (3) connected with the falling film heat exchanger (2) and used for extracting steam, a compressor unit connected with the separator (3) and the reboiler (8) respectively and used for increasing the temperature of the steam, rectifying the low-concentration ethanol raw material by a low-concentration ethanol recovery device body to obtain an ethanol finished product, separating the ethanol finished product by a separator (3) and a compressor unit, the steam after rectification is heated and then serves as a heating source of the rectifying tower (1), so that the matching of single-tower ethanol distillation and MVR evaporation technologies is realized, the reutilization rate of heat energy is improved, and the consumption of the heat energy is reduced.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide an acrylic acid purification device that energy was recycled retrieves the energy in the purification technology and recycles, improves the utilization efficiency of heat energy.

Another object of the present invention is to provide an acrylic acid purification device with energy recycling, which recovers the heat energy discharged from the top of the rectification tower and then recycles the heat energy to the rectification tower to reduce the manufacturing cost of the product.

Another object of the present invention is to provide an acrylic acid purification device with energy recycling, which reduces or eliminates the use of refrigerant, improves the safety of production, and improves the environmental friendliness.

The utility model discloses acrylic acid purification device that energy was recycled adopts Mechanical Vapor Recompression (MVR) heat pump technique to water is as the coolant at the rectifying column top, carries out the pressure boost with rectifying column top exhaust steam after, and the feedback makes heat energy obtain recycling to the rectifying column bottom, thereby has reduced the energy consumption by a wide margin.

An acrylic acid purification device with energy reuse is characterized in that an outlet at the top of a rectifying tower is connected with a condenser; the outlet of the condenser is connected with the storage tank;

an outlet at the bottom of the rectifying tower is connected with a tube pass inlet of a reboiler, and a tube pass outlet of the reboiler is connected with a tower body of the rectifying tower; a shell pass inlet of the reboiler is connected with an outlet of the MVR device, and a shell pass outlet is connected with the storage tank;

the inlet of the MVR device is connected with the water vapor outlet at the upper part of the storage tank. The condenser exchanging heat with the MVR device is a vertical shell-and-tube falling film evaporator.

The storage tank comprises a liquid accommodating cavity and a steam accommodating cavity, the liquid accommodating cavity is positioned below the steam accommodating cavity, and condensed water generated by heat exchange enters the solution cavity; the vapor containing cavity provides a buffer space for water vapor from the purifying device.

The utility model discloses a device still sets up LLP low pressure steam bypass on the pipeline between the export of connecting the MVR device and reboiler shell side entry, at the beginning of implementing acrylic acid purification technology, will come from steam system's LLP low pressure steam as the replenishment to satisfy required energy, namely make the temperature 110 ℃ -150 ℃ of (LLP low pressure steam) MVR steam in the reboiler shell side, pressure control is at 50kPaG ~ 250kPaG, in order to provide sufficient heat and temperature with heating boiling column cauldron material.

According to the needs, the utility model discloses a device still sets up the pump on the pipeline of connecting each device/device to the pump sending mode drive liquid and gas flow.

Usually, 2 or more than 2 rectifying towers are adopted to purify the acrylic acid, and in order to further improve the efficiency, the energy recycling method of the utility model recycles the energy of 2 rectifying towers for 2 or 3 rectifying towers.

Each condenser is connected to the outlet of the top of the 1 rectifying column.

Each reboiler is correspondingly connected with the outlet at the bottom of the rectifying tower of 1 seat, and the material discharged from the bottom of the rectifying tower enters the reboiler and returns to the rectifying tower after heat exchange of a tube pass.

The generated condensed water or water vapor is guided into the storage tank through a pipeline. Set up vacuum apparatus on the storage tank to the realization maintains the vapour pressure in the storage tank at 5 ~ 80 kPaA's absolute pressure, and it is required to do benefit to the admission that the vapour satisfies the MVR device, and tank bottoms portion configuration steam pipeline, with the temperature in the regulation jar, thereby guarantee MVR inlet temperature.

Another apparatus for purifying acrylic acid with reuse of energy, comprising:

a shell pass inlet of the first condenser is connected with a top outlet of the first rectifying tower, a tube pass inlet is connected with an outlet of the MVR device, and a tube pass outlet is connected with the storage tank;

a tube pass inlet of the second condenser is connected with a tower top outlet of the second rectifying tower, a shell pass inlet is connected with an outlet of the MVR device, a shell pass outlet is connected with an inlet of the gas-liquid separator, and an outlet of the gas-liquid separator is connected with the storage tank;

each reboiler is correspondingly connected with the tower bottom outlet of 1 rectifying tower, the outlet at the tower bottom of the rectifying tower is connected with the tube pass inlet of the reboiler, and the tube pass outlet is connected with the tower body of the rectifying tower; a shell pass inlet of the reboiler is connected with an outlet of the MVR device, and a shell pass outlet is connected with the lower part of the storage tank;

the inlet of the MVR device is connected with the water vapor outlet at the upper part of the storage tank;

the storage tank comprises a liquid containing cavity and a steam containing cavity, wherein the liquid containing cavity is positioned below the steam containing cavity and is used for receiving condensed water generated after heat exchange; the vapor containing cavity provides a buffer space for water vapor from the purifying device.

When the acrylic acid purification process adopts 3 rectifying towers, the outlet of the MVR device is respectively connected with the shell pass inlets of the first reboiler, the second reboiler and the third reboiler;

an outlet at the bottom of the first rectifying tower is connected with a tube pass inlet of the first reboiler, and a tube pass outlet is connected with a tower body of the first rectifying tower; a shell pass inlet of the first reboiler is connected with an outlet of the MVR device, and a shell pass outlet is connected with the lower part of the storage tank;

an outlet at the bottom of the second rectifying tower is connected with a tube pass inlet of the second reboiler, and a tube pass outlet is connected with the tower body of the second rectifying tower; a shell pass inlet of the second reboiler is connected with an outlet of the MVR device, and a shell pass outlet is connected with the lower part of the storage tank;

an outlet at the bottom of the third rectifying tower is connected with a tube pass inlet of a third reboiler, and a tube pass outlet is connected with a tower body of the third rectifying tower; and a shell pass inlet of the third reboiler is connected with an outlet of the MVR device, and a shell pass outlet is connected with the lower part of the storage tank.

The utility model discloses beneficial effect that technical scheme realized:

the utility model discloses an in the device uses acrylic acid refining process with industry heat pump MVR technique to it is high to solve the refined energy consumption of acrylic acid, the dual extravagant problem of top of the tower cauldron energy, thereby reduces the running cost of device by a wide margin, and reduces the fixed investment expense of devices such as steam generator and cooling tower, improves the bulk utilization of heat energy.

The utility model discloses a device adopts MVR technique with steam and hydrologic cycle fluid medium, does not contact with organic material, does not use the refrigerant harmful to the environment, dangerous or corrosivity, has greatly reduced safety, environmental protection risk.

The condensed water is used as a cooling medium at the top of the rectifying tower, the steam at the bottom of the rectifying tower is the steam after the MVR system is pressurized, and fresh steam and fresh cooling water are not adopted completely, so that the operating cost of acrylic acid rectification and the fixed investment cost of a steam generating device and a cooling water system are reduced.

Adopt in acrylic acid purification the utility model discloses a device can save or reduce cooling tower's scale, makes the whole area of occupation of land of device than traditional technology littleer.

Drawings

FIG. 1 is a schematic view showing the flow of the device used in the acrylic acid purification process, wherein the arrow direction marks the moving direction of the material.

Detailed Description

The technical solution of the present invention is described in detail below with reference to the accompanying drawings. The embodiments of the present invention are only used for illustrating the technical solutions of the present invention and not for limiting, although the present invention is described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced with other equivalent solutions without departing from the spirit and scope of the present invention, which should be covered by the scope of the claims of the present invention.

In the acrylic acid purification process, the acrylic acid purification process implemented by 3 rectifying towers is widely adopted by the industry and is also a key research object in the industry. In the process, a first rectifying tower is used for rectifying light components, a second rectifying tower is used for removing acetic acid, and a third rectifying tower is used for refining products. The energy recycling scheme of this embodiment is illustrated by combining with a 3-column purification process, and fig. 1 is a schematic flow chart of the apparatus of the present invention for an acrylic acid purification process. As shown in fig. 1, a first rectification column 110, a second rectification column 120, a third rectification column 130, an MVR device 200, and a storage tank 300.

The storage tank 300 includes a liquid-containing chamber 310 and a vapor-containing chamber 320, and the vapor-containing chamber 320 is disposed above the liquid-containing chamber 310. A vacuum device 600 is also arranged on the device to maintain the gas pressure in the storage tank 300 within the absolute pressure range of 5-80 kPaA. The tank bottom is provided with a vapor line (not shown) to regulate the tank internal temperature to ensure MVR inlet air temperature.

The first condenser 410 and the second condenser 420 are connected to the top outlets of the first rectifying column 110 and the second rectifying column 120, respectively. The shell pass inlet of the first condenser 410 is connected with the outlet of the top of the first rectifying tower 110, the tube pass inlet is connected with the outlet of the MVR device 200, and the tube pass outlet is connected with the storage tank 300. The condensed water from the tube pass outlet flows into the liquid containing cavity 310 through the pipeline, and the water vapor from the tube pass outlet is guided into the vapor containing cavity 320 through the pipeline. The tube-side inlet of the second condenser 420 is connected with the outlet of the top of the second rectifying tower 120, the shell-side inlet is connected with the outlet of the MVR device 200, and the shell-side outlet is connected with the inlet of the gas-liquid separator 700. The outlet of the gas-liquid separator is connected to the storage tank 300, the outflow condensed water flows into the liquid-holding chamber 310 through a pipe, and the outflow steam is guided into the steam-holding chamber 320 through a pipe.

The first reboiler 510, the second reboiler 520, and the third reboiler 530 are connected to the bottom outlets of the first rectifying column 110, the second rectifying column 120, and the third rectifying column 130, respectively. The outlet at the bottom of the first rectification column 110 is connected to the tube side inlet of the first reboiler 510, and the tube side outlet is connected to the column body of the first rectification column 110. The outlet at the bottom of the second rectifying tower 120 is connected with the tube pass inlet of the second reboiler 520, and the tube pass outlet is connected with the tower body of the second rectifying tower 120. The outlet at the bottom of the third rectifying tower 130 is connected with the tube side inlet of the third reboiler 530, and the tube side outlet is connected with the tower body of the third rectifying tower 130.

The MVR device 200 is connected to the vapor outlet of the storage tank 300, the outlet of the MVR device is connected to the shell side inlets of the first reboiler 510, the second reboiler 520, and the third reboiler 530, respectively, and the shell side outlet is connected to the liquid holding chamber of the storage tank. The vapor in the vapor containing cavity 320 enters the MVR device 200 to be heated, and then enters the first reboiler 510, the second reboiler 520, and the third reboiler 530, respectively, and then is subjected to shell-side heat exchange to discharge MVR condensed water. The drained MVR condensed water flows back into the liquid-holding chamber 310.

The water in the liquid-containing chamber 310 is generally low in temperature (40 ℃ to 50 ℃), and is introduced into the first condenser 410 and the second condenser 420 to be reused as a cooling medium. Which flows into the liquid accommodating chamber 310 after passing through the heat exchange tube from one end of the first condenser 410 and flows out from the other end. The water introduced into one end of the second condenser 420 is heat-exchanged in the shell side, and then flows out from the other end to enter the gas-liquid separator 700. The gas-liquid separator 700 is connected to an outlet of the second condenser 420, and performs steam-water separation on the steam from the second condenser 420, wherein the steam is guided into the steam containing cavity 320 for reuse, and the condensed water flows into the liquid containing cavity 310 for reuse. When the amount of water in the first liquid containing chamber 310 is excessive, the water can be discharged.

Therefore, the MVR device 200 is applied to the acrylic acid purification process, so that the energy in the rectifying tower is fully utilized. In the energy reuse method of the present embodiment, the coolant is cooled by water and flows into the first condenser 410 and the second condenser 420, respectively. The water flowing into the first condenser 410 returns to the storage tank 400 for reuse through the steam and the condensed water generated after the heat exchange of the tube pass. The water flowing into the second condenser 420 enters the steam-water separator 700 after shell-side heat exchange, and the steam and the condensed water in the water both return to the storage tank 400 for reuse. Introducing first steam discharged from the top of the first rectifying tower 110 into a first condenser 410, and discharging the first steam after shell-side heat exchange; the second vapor discharged from the top of the second rectification column 120 is introduced into the second condenser 420 and discharged after passing through the tube pass.

The pressure of the steam in the storage tank is maintained at 5-80 kPaA absolute pressure, so that the steam can meet the steam admission requirement of the MVR device. And after the cooled steam is buffered at the upper part of the storage tank, the cooled steam enters the MVR device and is pressurized and heated, and the MVR steam discharged from the outlet of the MVR device is respectively led into the first reboiler, the second reboiler and the third reboiler and flows through a shell pass. The MVR vapor in the reboiler shell side is at a temperature of 110 deg.C to 150 deg.C and a pressure of 50kPaG to 250kPaG to provide sufficient heat and temperature to heat the boiling column bottoms. The material at the bottom of the first rectification column 110 is heat exchanged in the first reboiler 510, and the MVR vapor forms a first MVR condensed water and flows into the storage tank 400 again. The tower bottom material of the second rectifying tower 120 is heat exchanged in the second reboiler 520, and the MVR steam forms second MVR condensed water and flows into the storage tank 400 again. The material at the bottom of the third rectifying tower 130 is heat exchanged in the third reboiler 530, and the MVR steam forms third MVR condensed water to flow into the storage tank 400 again.

The skilled person can provide the energy required for the flow of the liquid and the vapour in a pumping manner, as required, in order to increase the flow velocity of the liquid and the vapour or to compensate for the kinetic energy dissipated in the flow. In the method of this embodiment, the energy required for the respective reboilers to participate in the shell-side heating medium at the beginning of the acrylic acid purification process is provided by Low Pressure steam (LLP) from the steam system, and after the operation, the Low Pressure steam is replaced by the steam provided by the MVR device.

After the energy recycling device provided by the embodiment is used for an acrylic acid purification process, the energy recycling efficiency is obviously improved, and the cost is obviously reduced. Taking an apparatus for producing 8 ten thousand tons of acrylic acid in three rectification columns as an example, the first reboiler connected to the first rectification column was about 33000kw, the second reboiler connected to the second rectification column was about 6500kw, and the third reboiler connected to the third rectification column was about 4500 kw. By adopting the energy recycling method provided by the embodiment, 3000-4500 ten thousand RMB is saved according to 8000 hours running time of the whole year. Meanwhile, after the energy recycling method provided by the embodiment is adopted, the refrigerant used by the condenser connected with the top of each rectifying tower is cheaper, the refrigerant used for refrigeration equipment is reduced, and the occupied area is saved by about 1000 square meters. According to 8000 hours all the year, the running cost of the refrigerating unit is saved by about 1300 ten thousand, the running cost of the water tower is saved by about 200 ten thousand, and the two items are at least saved by 1500 ten thousand RMB.

Claims

1. An acrylic acid purification device with energy reuse is characterized in that an outlet at the top of a rectifying tower is connected with a condenser; the outlet of the condenser is connected with the storage tank;

the storage tank comprises a liquid containing cavity and a steam containing cavity, the liquid containing cavity is positioned below the steam containing cavity, and condensed water generated by heat exchange enters the liquid containing cavity; the vapor containing cavity provides a buffer space for water vapor from the purifying device.

2. The energy-reusing acrylic acid purifying apparatus according to claim 1, wherein the condenser exchanging heat with the MVR apparatus is a vertical shell-and-tube falling film evaporator.

3. The apparatus according to claim 1, wherein the acrylic acid purification process comprises 2 or more distillation columns.

4. The apparatus for purifying energy-reused acrylic acid as claimed in claim 3, wherein each of the condensers is connected with the outlet of the top of 1 of the rectifying towers, respectively.

5. The apparatus for purifying acrylic acid with energy reuse according to claim 3, wherein each of said reboilers is connected to the bottom outlet of 1 of said distillation columns, and the material discharged from the bottom of said distillation columns enters said reboilers and returns to said distillation columns after heat exchange in tube pass.

6. The apparatus for purifying acrylic acid by recycling energy as claimed in claim 1, further comprising a pump disposed on the pipeline for guiding the liquid or gas to drive the liquid or gas to flow in a pumping manner.

7. An acrylic acid purification device with energy reuse is characterized by comprising

8. The apparatus for purifying acrylic acid by reusing energy as claimed in claim 7, wherein 3 rectifying towers are used, and the outlets of the MVR apparatus are connected to the shell side inlets of the first reboiler, the second reboiler and the third reboiler respectively;