CN219342049U - Process device for dehydration and deacidification of acrylic acid aqueous solution - Google Patents
Process device for dehydration and deacidification of acrylic acid aqueous solution Download PDFInfo
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Abstract
The utility model relates to a process device for dehydration and deacidification of an acrylic acid aqueous solution. The whole device at least comprises two towers of a light component removing tower (T110) and an extracting tower (T120) and matched equipment thereof; the acetic acid content of the extraction phase of the extraction tower (T120) tower kettle is high, and the acetic acid is used as discharged wastewater; the liquid phase of the tower bottom of the light component removal tower (T110) is the mixture of acrylic acid, entrainer and other components, and the mixture is sent to the subsequent working section. The method can be used for carrying out dehydration and deacidification operation on the acrylic acid aqueous solution obtained by continuous absorption or other ways of propylene oxidation reaction gas to obtain a crude acrylic acid product. The energy consumption is reduced, and meanwhile, the recycling of low-concentration acid water can be realized, the accumulation of acetic acid in the system is avoided, and the consumption of absorbing fresh process water is reduced. The utility model overcomes the defects of the prior art, can be suitable for acrylic acid aqueous solution raw materials with different concentrations, has obvious practicality and economic benefit, and has wide application prospect.
Description
Technical Field
The utility model relates to a process device for dehydrating and deacidifying an acrylic acid aqueous solution, which can be used for dehydrating and deacidifying the acrylic acid aqueous solution obtained by continuously absorbing propylene oxidation reaction gas or other ways to obtain a crude acrylic acid product, and can realize the recycling of low-concentration acid water, avoid the accumulation of acetic acid in a system and reduce the consumption of fresh process water in an absorption section while reducing the energy consumption.
Background
Acrylic acid is unsaturated fatty acid, is an important industrial derivative of propylene, and is also one of important organic chemical raw materials. Acrylic acid contains active double bond and carboxyl functional group, is especially suitable for preparing high water absorption materials, dispersing agents, flocculating agents, thickening agents and the like, and is widely used in a plurality of fields of chemical fiber, textile, coating, water treatment, daily necessities and the like.
In the existing acrylic acid production process, a propylene gas phase oxidation method is widely used, propylene and air are used as raw materials, oxidation reaction is carried out through a fixed bed catalyst bed layer in the presence of water vapor and other inert gases, the reaction is divided into two steps, in the first step, propylene is oxidized into acrolein, in the second step, the acrolein is oxidized into acrylic acid, an acrylic acid gas phase mixture is obtained at the outlet of a reactor, the acrylic acid gas phase mixture mainly comprises acrylic acid gas, nitrogen, aldehyde compounds, carboxylic acid compounds, carbon dioxide, carbon monoxide, oxygen and the like, and an acrylic acid product is obtained through a refining separation system.
Currently, the commonly used acrylic acid gas phase separation methods mainly comprise three different technical routes: organic solvent absorption rectification technology, water absorption azeotropic rectification technology and water absorption extraction rectification technology. The organic solvent absorption and rectification technology has the advantages of short flow and relatively low energy consumption; the defects are that the solvent is needed to absorb the acrylic acid, the operation temperature is high, the acrylic acid is easy to polymerize, and the operation period is short; the water absorption azeotropic distillation technology has the advantages of shorter flow, low investment cost, high energy consumption and high running cost, and the defect that an entrainer is needed; the water absorption, extraction and rectification technology has the advantages of low energy consumption and low operation cost; the disadvantages are longer process, high investment cost, high consumption of extractant and polymerization inhibitor.
Chinese patent CN1903738A provides an "acrylic acid wastewater treatment process" suitable for acrylic acid wastewater discharged from an acrylic acid plant. The acrylic acid waste water treatment adopts reverse osmosis membrane separation and rectification working procedures, the acrylic acid waste water is separated by a membrane, the purified water at the permeation side is discharged out of the boundary region, and the organic matters at the permeation side are sent into a rectification tower to separate acrylic acid, toluene, acetic acid and water, and acrylic acid, toluene and acetic acid are respectively recovered. The acrylic acid and the toluene separated by the process method also need to enter a light component tower of an acrylic acid device to recycle the acrylic acid and the toluene, and the acetic acid and the water obtained by separation also need to enter an acetic acid recycling system to recycle the acetic acid, so that a product with higher concentration can not be obtained; the operation pressure of the reverse osmosis membrane is high (1-10 MPa), the service life of the reverse osmosis membrane is limited, and the reverse osmosis membrane needs to be replaced frequently, so that the operation cost of the process method is high.
CN1865216a provides a process for azeotropic refining of acrylic acid and recovering acetic acid, in which ethylcyclohexane, toluene, ethyl propionate and toluene are used as entrainer in azeotropic distillation of acrylic acid, an acrylic acid azeotropic tower and a deacetosis tower are provided to remove water and acetic acid in crude acrylic acid solution, and an organic film, a stripping tower and an acetic acid azeotropic tower are additionally provided to concentrate the by-product acetic acid with concentration of 2-8% (except for special description, all refer to mass percent in the specification) to concentration of more than or equal to 85%. The process method has higher dehydration rate and acetic acid removal rate, but has higher azeotropic distillation energy consumption, and the entrainer is a plurality of material ligands, namely more components to be separated are introduced into the system, so that the separation difficulty is also improved, and the separation energy consumption is increased; the organic film is a three-stage reverse osmosis film, so that the equipment cost is high, the service life is limited, periodic replacement is required, and the equipment cost and the operation cost are increased.
CN102775295a discloses a method for purifying acrylic acid, which comprises two technological processes of an absorption tower and a purification tower, and through coupling of acrylic acid cooling, absorption and purification processes, the recovery and purification of acrylic acid are completed by using a device consisting of the two towers, meanwhile, water is recycled as an absorbent and a coolant, and other solvents (extractant and entrainer) are not used, so that the pollution of the solvent to the environment is avoided. The method has relatively simple flow, reduces equipment investment cost and operation cost, but the method adopts the acetic acid aqueous solution at the top of the absorption tower as an absorbent, so that the acrylic acid content in tail gas at the top of the tower is higher (about 0.3 wt%), the propylene unit consumption is increased, and the production cost is increased more; meanwhile, as the liquid phase extraction of the acetic acid aqueous solution is not arranged in the device, the content of acrylic acid in the tail gas at the top of the tower is reduced, and the content of acetic acid in the tower bottom of the absorption tower is increased, so that the quality of acrylic acid products extracted by the purification tower is influenced.
CN109232232a discloses a method for refining acrylic acid, which performs quenching absorption of high concentration gas, reabsorption of low concentration gas, purification, extraction and stripping of acrylic acid process gas, couples a cooling process, an absorption process and a purification process of an acrylic acid gas phase mixture, performs subsequent acid water treatment, improves the absorption process, and does not use an entrainer in the refining process. The method has relatively simple flow and reduced operation cost, but because the desalted water is required to be added from the top of the light component removal tower in the reabsorption process, the desalted water is consumed, and the acid discharge water amount outside the system is increased; and the liquid phase extraction of the acetic acid aqueous solution is not arranged at the middle and upper parts of the light component removing tower, so that the acetic acid content of the tower kettle of the absorption tower is increased, and the quality of the acrylic acid product extracted by the purification tower is affected.
The technical methods provided by CN102775295A and CN109232232A have a common problem, and in order to reduce the content of acetic acid in the system and meet the quality of acrylic acid products, the temperature of the tail gas for incineration is forced to be increased, so that a small amount of acrylic acid is caused to be removed from the tail gas incineration system along with the tail gas and acetic acid, and the material consumption and the yield of the device are increased.
Disclosure of Invention
The utility model aims to provide a process device for dehydrating and deacidifying an acrylic acid aqueous solution, which can be used for dehydrating and deacidifying an acrylic acid aqueous solution obtained by continuously absorbing propylene oxidation reaction gas or other ways to obtain a crude acrylic acid product. The utility model can realize the recycling of low-concentration acid water, avoid the accumulation of acetic acid in the system and reduce the consumption of fresh process water in the absorption section while reducing the energy consumption. The utility model overcomes the defects of the prior art, can be suitable for acrylic acid aqueous solution raw materials with different concentrations, has obvious practicality and economic benefit, and has wide application prospect.
The utility model provides a process method for dehydration and deacidification of an acrylic acid aqueous solution, which mainly comprises the following steps:
1) At least comprises two towers, namely a light component removing tower T110 and an extracting tower T120.
2) The upper part of the light component removing tower T110 adopts a baffle tower structure, and the lower part is a conventional structure without a baffle; an azeotropic distillation section S1102 is arranged above the feeding side of the partition plate, and a stripping section S1103 is arranged below the feeding side and at the non-partition plate part at the lower part; the other side of the partition board is provided with a deacetylation section S1101.
3) The aqueous acrylic acid solution from the absorption section or other routes enters the top of stripping section S1103 of the light ends removal column T110.
4) The gas phase condensate at the top of the tower of the deacetylation section S1101 of the light component removal tower T110 enters the bottom of the extraction tower T120 after passing through a deacetylation condensate tank V1101.
5) The gas phase condensate at the top of the azeotropic rectifying section S1102 of the light component removal tower T110 enters the azeotropic phase-splitting tank V1102, the water phase after phase splitting is wastewater with low acetic acid content and is divided into two parts, one part enters the top of the extraction tower T120, and the other part is extracted to be used as absorption water recycled by the absorption tower.
6) The oil phase separated by the azeotropic phase separation tank V1102 is used as an entrainer to be respectively fed into the tops of the deacetylation section S1101 and the azeotropic distillation section S1102 of the light component removal tower T110.
7) The raffinate phase at the top of the extraction tower T120 is mixed with the gas phase condensate at the top of the azeotropic rectifying section S1102 of the light component removal tower T110 and then enters the azeotropic phase separation tank V1102.
8) The acetic acid content of the extraction phase of the T120 tower kettle of the extraction tower is higher, and the acetic acid is used as discharged wastewater.
9) The liquid phase of the tower bottom of the light component removal tower T110 is a mixed material of acrylic acid, entrainer and other components, and the mixed material is sent to a subsequent working section.
The process method provided by the utility model comprises the following steps:
1) The raw material acrylic acid aqueous solution 1 enters the top of a stripping section S1103 of the light component removal tower T110, and a return material (25) from the top of the acetic component removal tower (T130) enters a acetic component removal section of the light component removal tower (T110) (S1101).
2) The gas phase 2 at the top of the deacetylation section S1101 of the light component removal tower T110 enters a deacetylation acid condenser E1102 for condensation, the cold condensate 3 enters a deacetylation condensate tank V1101, and the liquid phase 4 of the deacetylation condensate tank V1101 enters the bottom of the extraction tower T120.
3) The gas phase 5 at the top of the azeotropic rectifying section S1102 of the light component removal tower T110 enters an azeotropic condenser E1103 to be condensed, and the cooled noncondensable gas 6 is connected with a vacuum system; the condensate 7 of the azeotropic condenser E1103 enters an azeotropic phase-splitting tank V1102 to split phases, the phase-split oil phase 8 is divided into two streams, the first stream is taken as reflux 9 of a deacetylation section S1101 of a lightness-removing column T110 to directly return to the top of the deacetylation section S1101 of the lightness-removing column T110, and the second stream is taken as reflux 10 of an azeotropic rectifying section S1102 of the lightness-removing column T110 to directly return to the top of the azeotropic rectifying section S1102 of the lightness-removing column T110; the water phase 11 after phase separation is divided into two streams, the first stream is taken as an extractant 12 to enter the top of an extraction tower T120, and the second stream is taken as absorption water 13 recycled by an absorption tower to be sent to an absorption section.
4) And a mixed material 14 of acrylic acid, entrainer and other components is sent out of the device to the subsequent working section, wherein the liquid phase of the tower kettle at the bottom of the stripping section S1103 of the light component removal tower T110.
5) The raffinate phase 15 at the top of the extraction tower T120 is mixed with the gas phase condensate 7 at the top of the azeotropic rectifying section S1102 of the light component removal tower T110 and then enters the azeotropic phase-splitting tank V1102; the extraction phase of the extraction tower T120 tower kettle is taken as the discharged wastewater 16 to be sent out of the device.
According to the process method provided by the utility model, on the basis of the two towers, the light component removing tower T110 does not adopt a baffle tower structure, the light component removing tower T110 acetic acid removing section S1101 can be separated from the azeotropic rectifying section S1102 and the stripping section S1103, an independent light component removing tower B T B is arranged as the acetic acid removing section S1101, and the side line is led from the stripping section S1103 of the light component removing tower T110 to extract the gas phase into the bottom of the acetic acid removing section S1101 of the light component removing tower B T B.
According to the process method provided by the utility model, on the basis of the two towers, a baffle tower structure is not adopted in the light component removing tower T110, a light component removing tower T110 acetic acid removing section S1101 can be separated from an azeotropic rectifying section S1102, a stripping section S1103 is divided into two parts which are connected in parallel, an independent light component removing tower B T B is arranged, and a stream of material is split from liquid phase material in the tower bottom of the light component removing tower T110 and enters the light component removing tower B T B.
According to the process method provided by the utility model, one part of liquid phase of the deacetylation condensate tank V1101 can enter the bottom of the extraction tower T120, and the other part enters the top of the deacetylation section S1101 of the lightness-removing tower T110.
According to the process method provided by the utility model, the raffinate phase at the top of the extraction tower T120 can also flow back to the top of the deacetylation section S1101 of the light component removal tower T110.
According to the process method provided by the utility model, on the basis of the two towers, the extraction tower T120 can be omitted; the water phase after the azeotropic phase separation tank V1102 phase-separates, except that the absorption water recycled by the absorption tower is sent to an absorption section, the rest water phase is mixed with the gas phase condensate at the top of the deacetylation section S1101 of the light component removal tower T110 and then enters the deacetylation condensate tank V1101; the water phase separated by the deacetylation condensate tank V1101 is taken as discharged wastewater to be sent out of the device, and the oil phase is mixed with gas phase condensate at the top of the azeotropic rectifying section S1102 of the light component removal tower T110 and then enters the azeotropic phase separation tank V1102.
According to the process method provided by the utility model, the returned material from the top of the deacetylation tower T130 can be mixed with the raw material acrylic acid aqueous solution and then fed into the top of the stripping section S1103 of the light ends removal tower T110.
According to the process method provided by the utility model, the lower part of the separator of the stripping section S1103 in the light component removal tower T110 can extend to the tower kettle, and the separator can only extend to the middle part of the stripping section S1103.
According to the process method provided by the utility model, the adopted energy-saving method is selected:
1) The mixture of acrylic acid, entrainer and other components extracted from the tower kettle of the light component removal tower T110 can be preheated for the feeding of the light component removal tower T110.
2) The feed to the light ends column T110 may be used as a cooling medium for the deacetylation column condenser E1102 and the azeotropic condenser E1103.
3) The steam condensate may be preheated for the feed to the light ends column T110.
The heat exchange and steam condensate between the hot material and the cold material in the system can preheat any material or the arrangement combination of the materials in the system, and the various heat exchange modes and the combination of the heat exchange modes are only supplementary to the process method for dehydrating and removing acetic acid from the acrylic acid aqueous solution provided by the utility model, but not limit the spirit of the utility model, and a person skilled in the relevant field can completely and properly change or change and combine the processes provided by the utility model to realize the technology. It is expressly intended that all such modifications and adaptations of the process flow provided by the present utility model, as well as such modifications and adaptations, which would be apparent to those of ordinary skill in the art, are intended to be within the spirit, scope and content of the present utility model.
According to the process method provided by the utility model, the heat source used by the light component removal tower reboiler E1101 can be fresh steam, heat conducting oil or material steam generated in the system.
According to the process method provided by the utility model, the de-acetic acid condenser E1102 and the azeotropic condenser E1103 can be air coolers or water coolers; the cooling medium can be circulating water, low-temperature water, chilled water or other cooling medium such as low-temperature materials in the system.
According to the process method provided by the utility model, in order to reduce material loss caused by bringing noncondensable gas into a vacuum system, a de-acetic acid tail cooler E1105 and an azeotropic tail cooler E1106 can be respectively arranged after the de-acetic acid condenser E1102 and the azeotropic condenser E1103, and the cooling medium can be low-temperature water, chilled water or other cryogenic media such as low-temperature materials in the system.
Typical operating conditions of the light component removal tower T110 according to the process method provided by the utility model are as follows: the operating pressure range of the tower top of the acetic acid removal section S1101 is 8-20 kPa, the operating pressure range of the tower top of the azeotropic distillation section S1102 is 10-20 kPa, the operating temperature range of the tower top of the acetic acid removal section S1101 is 40-55 ℃, the operating temperature range of the tower top of the azeotropic distillation section S1102 is 38-50 ℃, and the operating temperature range of the tower bottom is 70-89 ℃; the preferred operating conditions for the light ends column T110 are: the operation pressure of the top of the acetic acid removal section S1101 and the azeotropic distillation section S1102 is 15kPa, the operation pressure of the tower kettle is 20kPa, the operation temperature of the top of the acetic acid removal section S1101 is 52 ℃, the operation temperature of the top of the azeotropic distillation section S1102 is 40 ℃, and the operation temperature of the tower kettle is 83 ℃.
The utility model provides a process device for dehydration and deacetylation of an acrylic acid aqueous solution, which mainly comprises two towers of a light component removal tower T110 and an extraction tower T120 and connecting pipelines.
The raw material acrylic acid aqueous solution feed line is connected to the top of stripping section S1103 of the light component removal tower T110, and the return material line from the top of the acetic component removal tower T130 is connected to the lower part of acetic component removal section S1101 of the light component removal tower T110.
The top of a de-acetic acid section S1101 of the light component removal tower T110 is connected with a material side inlet of a de-acetic acid condenser E1102, a material side non-condensable gas outlet of the de-acetic acid condenser E1102 is connected with a vacuum system, a material side condensate outlet of the de-acetic acid condenser E1102 is connected with a de-acetic acid condensate tank V1101, and an outlet of the de-acetic acid condensate tank V1101 is connected with a tower kettle of the extraction tower T120.
The tower top of the azeotropic rectifying section S1102 of the light component removal tower T110 is connected with a material side inlet of an azeotropic condenser E1103, a material side noncondensable gas outlet of the azeotropic condenser E1103 is connected with a vacuum system, a material side condensate outlet of the azeotropic condenser E1103 is connected with an azeotropic phase separation tank V1102, an oil phase outlet of the azeotropic phase separation tank V1102 is respectively connected with the tower top of the acetic component removal section S1101 of the light component removal tower T110 and the tower top of the azeotropic rectifying section S1102, and a water phase outlet of the azeotropic phase separation tank V1102 is respectively connected with a tower top of the extraction tower T120 and an absorption tower reuse absorption water extraction pipeline.
The bottom of the light component removal tower T110 is respectively connected with a material side inlet of a light component removal tower reboiler E1101 and a mixed material extraction pipeline of acrylic acid, entrainer and other components, and a material side outlet of the light component removal tower reboiler E1101 is connected to a tower kettle of the light component removal tower T110.
The top of the extraction tower T120 is connected with an azeotropic phase separation tank V1102, and the bottom of the extraction tower T120 is connected with an effluent discharge pipeline.
The process provided by the utility model, and the person skilled in the relevant technical field can fully implement the appropriate internal logistics heat exchange method of the system according to the specific device conditions, and all the evolution process flows formed by the process method are considered to be in the spirit, scope and content of the utility model. The heat exchanger in the flow diagram is only schematic and its specific construction does not constitute any limitation on the utility model.
The utility model provides a process device for dehydrating and deacidifying an aqueous acrylic acid solution, which can be used for dehydrating and deacidifying the aqueous acrylic acid solution obtained by continuous absorption or other ways in propylene oxidation reaction gas to obtain a crude acrylic acid product. The utility model can realize the recycling of low-concentration acid water, avoid the accumulation of acetic acid in the system and reduce the consumption of absorbing fresh process water while reducing the energy consumption. The utility model overcomes the defects of the prior art, can be suitable for acrylic acid aqueous solution raw materials with different concentrations, has obvious practicality and economic benefit, and has wide application prospect.
Drawings
FIG. 1 is a process flow diagram of a conventional process method of three towers (an absorption tower T100, a light component removal tower T110 and a acetic acid removal tower T130) for obtaining a concentrated acrylic acid product by the steps of quenching absorption, azeotropic distillation, conventional distillation and acetic acid removal of raw material reaction gas adopted in the prior art.
Fig. 2 is a process flow diagram of a typical process for dehydration and deacidification of aqueous acrylic acid.
Fig. 3 is a schematic diagram of an evolution process of fig. 2, namely a modification process, and compared with the process provided in fig. 2, the light component removal tower T110 does not adopt a partition tower structure, the light component removal tower T110 acetic acid removal section S1101 can be separated from the azeotropic rectification section S1102 and the stripping section S1103, an independent light component removal tower B T B is provided as the acetic acid removal section S1101, and a side line is led from the light component removal tower T110 stripping section S1103 to extract a gas phase 17 into the bottom of the acetic acid removal section S1101 of the light component removal tower B T B.
Fig. 4 is a schematic diagram of an evolution process method of fig. 2, namely a modification process method two, and compared with the process provided in fig. 2, a light component removal tower T110 does not adopt a partition tower structure, a light component removal tower T110 acetic acid removal section S1101 can be separated from an azeotropic rectification section S1102, a stripping section S1103 is divided into two parts connected in parallel, an independent light component removal tower B T B is arranged, and a stream of material 20 is split from a tower bottom liquid phase material 19 of the light component removal tower T110 into a light component removal tower B T B.
Fig. 5 is a schematic diagram of an evolution process of fig. 2, namely a modification process three, and, with respect to the flow provided in fig. 2, a part of the liquid phase 4 of the deacidification condensate tank V1101 may enter the bottom of the extraction tower T120, and another part 23 enters the top of the deacidification section S1101 of the light component removal tower T110.
Fig. 6 is a schematic diagram of an evolution process of fig. 2, namely a modification process, and, with respect to the flow provided in fig. 2, the raffinate 15 at the top of the extraction tower T120 may also flow back to the top of the acetic acid removal section S1101 of the light component removal tower T110, and the lower portion of the separator of the stripping section S1103 in the light component removal tower T110 extends to the bottom of the tower.
FIG. 7 is a schematic diagram of an evolution process of FIG. 2, namely, a modification process five, and the extraction column T120 may be omitted, relative to the flow provided in FIG. 2; the water phase 11 after the azeotropic phase separation tank V1102 phase-separates, except that the absorption water 13 recycled by the absorption tower is sent to an absorption section, the rest water phase 12 is mixed with the gas phase condensate 3 at the top of the deacetylation section S1101 of the lightness-removing tower T110 and then enters the deacetylation condensate tank V1101; the water phase 16 after the phase separation of the deacetylation condensate tank V1101 is taken as an external drainage waste water sending device, and the oil phase 24 is mixed with the gas phase condensate 7 at the top of the azeotropic rectifying section S1102 of the lightness-removing column T110 and then enters the azeotropic phase separation tank V1102.
Fig. 8 shows an evolution process of fig. 2, namely a modification process six, and, in contrast to the flow provided in fig. 2, the return material 25 from the top of the de-acetic acid tower T130 may also be mixed with the raw acrylic acid aqueous solution 1 and then fed into the top of the stripping section S1103 of the de-light ends tower T110.
Detailed Description
Specific embodiments of the utility model are described in detail below with reference to the drawings, but are merely illustrative of the utility model and not limiting.
Unless specifically indicated, the composition, structure, materials (connecting lines for connecting the respective columns, etc.), reagents, etc. of the process equipment such as the columns, etc. which are not specifically used in the examples, are commercially available or can be obtained by a method well known to those skilled in the art. The specific experimental methods, operating conditions involved are generally as set forth in conventional process conditions as well as in handbooks, or as recommended by the manufacturer.
Application example 1:
the method can be used for the acrylic acid dehydration and deacetylation process of acrylic acid aqueous solutions with different concentrations.
As shown in fig. 2, the raw material acrylic acid aqueous solution 1 enters the top of stripping section S1103 of the light component removal tower T110, and the return material 25 from the top of the acetic component removal tower T130 enters the acetic component removal section S1101 of the light component removal tower T110.
The gas phase 2 at the top of the deacetylation section S1101 of the light component removal tower T110 enters a deacetylation acid condenser E1102 for condensation, the cold condensate 3 enters a deacetylation condensate tank V1101, and the liquid phase 4 of the deacetylation condensate tank V1101 enters the bottom of the extraction tower T120.
The gas phase 5 at the top of the azeotropic rectifying section S1102 of the light component removal tower T110 enters an azeotropic condenser E1103 to be condensed, and the cooled noncondensable gas 6 is connected with a vacuum system; the condensate 7 of the azeotropic condenser E1103 enters an azeotropic phase-splitting tank V1102 to split phases, the phase-split oil phase 8 is divided into two streams, the first stream is taken as reflux 9 of a deacetylation section S1101 of a lightness-removing column T110 to directly return to the top of the deacetylation section S1101 of the lightness-removing column T110, and the second stream is taken as reflux 10 of an azeotropic rectifying section S1102 of the lightness-removing column T110 to directly return to the top of the azeotropic rectifying section S1102 of the lightness-removing column T110; the water phase 11 after phase separation is divided into two streams, the first stream is taken as an extractant 12 to enter the top of an extraction tower T120, and the second stream is taken as absorption water 13 recycled by an absorption tower to be sent to an absorption section.
And a mixed material 14 of acrylic acid, entrainer and other components is sent out of the device to the subsequent working section, wherein the liquid phase of the tower kettle at the bottom of the stripping section S1103 of the light component removal tower T110.
The raffinate phase 15 at the top of the extraction tower T120 is mixed with the gas phase condensate 7 at the top of the azeotropic rectifying section S1102 of the light component removal tower T110 and then enters the azeotropic phase-splitting tank V1102; the extraction phase of the extraction tower T120 tower kettle is taken as the discharged wastewater 16 to be sent out of the device.
The heat source used in the light ends column reboiler E1101 is live steam, heat transfer oil, or material steam generated inside the system.
The condensate of the live steam added by the system can be preheated for the feed.
The de-acetic acid condenser E1102 and the azeotropic condenser E1103 may be air coolers or water coolers; the cooling medium can be circulating water, low-temperature water, chilled water or other cooling medium such as low-temperature materials in the system.
Typical operating conditions for the light ends column T110 in example 1 are given below: the operating pressure range of the tower top of the acetic acid removal section S1101 is 8-20 kPa, the operating pressure range of the tower top of the azeotropic distillation section S1102 is 8-20 kPa, the operating temperature range of the tower top of the acetic acid removal section S1101 is 40-55 ℃, the operating temperature range of the tower top of the azeotropic distillation section S1102 is 38-50 ℃, and the operating temperature range of the tower bottom is 70-89 ℃.
Preferred operating conditions for the light ends column T110 in example 1 are given below: the operation pressure of the top of the acetic acid removal section S1101 and the azeotropic distillation section S1102 is 15kPa, the operation pressure of the tower kettle is 20kPa, the operation temperature of the top of the acetic acid removal section S1101 is 52 ℃, the operation temperature of the top of the azeotropic distillation section S1102 is 40 ℃, and the operation temperature of the tower kettle is 83 ℃.
The acetic acid content in the wastewater at the top of the light component removal tower is about 7.3% and the acetic acid content in the material at the bottom of the tower is about 5% by adopting the conventional process shown in fig. 1. By adopting the typical flow path shown in fig. 2 and provided by the patent, the acetic acid content in the reclaimed absorption water 7 of the tower top absorption tower of the light component removal tower T110 can be reduced to 3.4%, the acetic acid content in the discharged wastewater 10 can be increased to 18.6%, and the acetic acid content in the tower kettle material 12 is about 3.5%. The process method for dehydration and deacidification of the acrylic acid aqueous solution can effectively reduce the concentration of acetic acid in the system, avoid excessive accumulation of acetic acid in the system, and is favorable for obtaining high-purity acrylic acid products.
Application example 2:
as shown in fig. 3, which is an evolution process method of fig. 2, compared with the flow provided in fig. 2, the stripping tower T110 does not adopt a partition tower structure, the stripping section S1101 of the stripping tower T110 can be separated from the azeotropic rectifying section S1102 and the stripping section S1103, an independent stripping tower B T B is arranged as the stripping section S1101, and the gas phase 17 is drawn from the stripping section S1103 of the stripping tower T110 to enter the bottom of the stripping section S1101 of the stripping tower B T B.
Application example 3:
as shown in fig. 4, which is an evolution process method of fig. 2, compared with the flow provided in fig. 2, the light component removal tower T110 does not adopt a partition tower structure, a acetic acid removal section S1101 of the light component removal tower T110 can be separated from an azeotropic rectification section S1102, a stripping section S1103 is divided into two parts connected in parallel, an independent light component removal tower B T B is arranged, and a stream of material 20 is split from a liquid phase material 19 in a tower bottom of the light component removal tower T110 into a light component removal tower B T B.
Application example 4:
as shown in fig. 5, which is an evolution process method of fig. 2, relative to the flow provided in fig. 2, a part of the liquid phase 4 of the deacidification condensate tank V1101 may enter the bottom of the extraction tower T120, and another part of the liquid phase 23 enters the top of the deacidification section S1101 of the light component removal tower T110.
Application example 5:
as shown in FIG. 6, which is an evolution process method of FIG. 2, compared with the flow provided by FIG. 2, the raffinate phase 15 at the top of the extraction tower T120 can also flow back to the top of the deacetylation section S1101 of the light component removal tower T110, and the lower part of the stripping section S1103 clapboard in the light component removal tower T110 extends to the tower bottom.
Application example 6:
as shown in fig. 7, which is an evolution process of fig. 2, the extraction column T120 may be omitted, relative to the flow provided in fig. 2; the water phase 11 after the azeotropic phase separation tank V1102 phase-separates, except that the absorption water 13 recycled by the absorption tower is sent to an absorption section, the rest water phase 12 is mixed with the gas phase condensate 3 at the top of the deacetylation section S1101 of the lightness-removing tower T110 and then enters the deacetylation condensate tank V1101; the water phase 16 after the phase separation of the deacetylation condensate tank V1101 is taken as an external drainage waste water sending device, and the oil phase 24 is mixed with the gas phase condensate 7 at the top of the azeotropic rectifying section S1102 of the lightness-removing column T110 and then enters the azeotropic phase separation tank V1102.
Application example 7:
as shown in FIG. 8, which is an evolution process method of FIG. 2, the return material 25 from the top of the deacetylation tower T130 can also be mixed with the raw material acrylic acid aqueous solution 1 and then enter the top of the stripping section S1103 of the light ends removal tower T110, compared with the flow provided in FIG. 2.
The utility model provides a process device for dehydration and deacidification of an acrylic acid aqueous solution. The whole device at least comprises two towers of a light component removing tower T110 and an extraction tower T120 and matched equipment thereof, and can be used for carrying out dehydration and deacidification operation on an acrylic acid aqueous solution obtained by continuous absorption or other ways in propylene oxidation reaction gas to obtain a crude acrylic acid product. The method can realize the recycling of low-concentration acid water, avoid the accumulation of acetic acid in the system and reduce the consumption of absorbing fresh process water while reducing the energy consumption, overcomes the defects of the prior art, is applicable to the raw materials of acrylic acid aqueous solutions with different concentrations, has obvious practicality and economic benefit and has wide application prospect.
The above embodiments are described in detail, and those skilled in the relevant art can fully implement the technology by making appropriate modifications, alterations and combinations of the methods provided by the present utility model. It is expressly intended that all such modifications and alterations and rearrangements of the process streams provided by this utility model, as well as the practice of appropriate system internal flow heat exchange methods, etc., be considered to be within the spirit, scope, and content of this utility model as will become apparent to those skilled in the art.
Claims (5)
1. The technological device for dehydration and deacidification of acrylic acid aqueous solution is characterized in that: mainly comprises a light component removing tower (T110), an extracting tower (T120) and connecting pipelines;
the raw material acrylic acid aqueous solution feed line is connected to the top of the stripping section (S1103) of the light component removal tower (T110), and the return material line from the top of the acetic component removal tower (T130) is connected to the lower part of the acetic component removal section (S1101) of the light component removal tower (T110);
the top of a de-acetic acid section (S1101) of the de-light column (T110) is connected with a material side inlet of a de-acetic acid condenser (E1102), a material side non-condensable gas outlet of the de-acetic acid condenser (E1102) is connected with a vacuum system, a material side condensate outlet of the de-acetic acid condenser (E1102) is connected with a de-acetic acid condensate tank (V1101), and an outlet of the de-acetic acid condensate tank (V1101) is connected with a column kettle of the extraction column (T120);
the top of an azeotropic rectifying section (S1102) of the light component removal tower (T110) is connected with a material side inlet of an azeotropic condenser (E1103), a material side noncondensable gas outlet of the azeotropic condenser (E1103) is connected with a vacuum system, a material side condensate outlet of the azeotropic condenser (E1103) is connected with an azeotropic phase separation tank (V1102), an oil phase outlet of the azeotropic phase separation tank (V1102) is respectively connected with the top of a acetic component removal section (S1101) and the top of the azeotropic rectifying section (S1102) of the light component removal tower (T110), and a water phase outlet of the azeotropic phase separation tank (V1102) is respectively connected with a top of an extraction tower (T120) and a recycling absorption water extraction pipeline of an absorption tower;
the bottom of the light component removal tower (T110) is respectively connected with a material side inlet of a light component removal tower reboiler (E1101) and a mixed material extraction pipeline of acrylic acid, entrainer and other components, and a material side outlet of the light component removal tower reboiler (E1101) is connected to a tower kettle of the light component removal tower (T110);
the top of the extraction tower (T120) is connected with an azeotropic phase separation tank (V1102), and the bottom of the extraction tower (T120) is connected with a wastewater discharge pipeline.
2. The process unit according to claim 1, wherein: the light component removing tower (T110) does not adopt a baffle tower structure, a light component removing tower (T110) acetic acid removing section (S1101) is separated from an azeotropic rectifying section (S1102) and a stripping section (S1103), an independent light component removing tower B (T110B) is arranged as the acetic acid removing section (S1101), and a side line is led to collect gas phase from the stripping section (S1103) of the light component removing tower (T110) to enter the bottom of the acetic acid removing section (S1101) of the light component removing tower B (T110B).
3. The process unit according to claim 1, wherein: the light component removing tower (T110) does not adopt a baffle tower structure, a light component removing tower (T110) acetic acid removing section (S1101) is separated from an azeotropic rectifying section (S1102), a stripping section (S1103) is divided into two parts which are connected in parallel, an independent light component removing tower B (T110B) is arranged, and a stream of material is split from a liquid phase material in a tower bottom of the light component removing tower (T110) to enter the light component removing tower B (T110B).
4. The process unit according to claim 1, wherein: typical operating conditions for the light ends column (T110) are: the operating pressure range of the top of the acetic acid removing section (S1101) is 8-20 kPa, the operating pressure range of the top of the azeotropic rectifying section (S1102) is 8-20 kPa, the operating temperature range of the top of the acetic acid removing section (S1101) is 40-55 ℃, the operating temperature range of the top of the azeotropic rectifying section (S1102) is 38-50 ℃, and the operating temperature range of the bottom of the tower is 70-89 ℃.
5. The process unit according to claim 1, wherein: the light component removal column (T110) has the following operating conditions: the tower top operation pressure of the acetic acid removing section (S1101) and the azeotropic rectifying section (S1102) is 15kPa, the tower bottom operation pressure is 20kPa, the tower top operation temperature of the acetic acid removing section (S1101) is 52 ℃, the tower top operation temperature of the azeotropic rectifying section (S1102) is 40 ℃, and the tower bottom operation temperature is 83 ℃.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222196610.6U CN219342049U (en) | 2022-08-16 | 2022-08-16 | Process device for dehydration and deacidification of acrylic acid aqueous solution |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222196610.6U CN219342049U (en) | 2022-08-16 | 2022-08-16 | Process device for dehydration and deacidification of acrylic acid aqueous solution |
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| CN219342049U true CN219342049U (en) | 2023-07-14 |
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| CN202222196610.6U Active CN219342049U (en) | 2022-08-16 | 2022-08-16 | Process device for dehydration and deacidification of acrylic acid aqueous solution |
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| CN (1) | CN219342049U (en) |
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