CN219128328U - Membrane tower coupling equipment for recycling propylene glycol monomethyl ether - Google Patents
Membrane tower coupling equipment for recycling propylene glycol monomethyl ether Download PDFInfo
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- CN219128328U CN219128328U CN202223466608.2U CN202223466608U CN219128328U CN 219128328 U CN219128328 U CN 219128328U CN 202223466608 U CN202223466608 U CN 202223466608U CN 219128328 U CN219128328 U CN 219128328U
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Abstract
The utility model provides a membrane tower coupling device for recovering propylene glycol monomethyl ether, a pretreatment rectifying tower; the pretreatment rectifying tower is provided with a propylene oxide waste liquid inlet, a pre-concentration propylene glycol monomethyl ether mixture outlet and a bottom material outlet; the bottom material outlet is connected with a tower bottom reboiler, and the gas phase outlet of the tower bottom reboiler is connected with a pretreatment rectifying tower; a double-membrane pervaporation dehydration system; the double-membrane pervaporation dehydration system comprises a preferential organic-permeable membrane assembly and a plurality of groups of preferential water-permeable molecular sieve membrane assemblies; the pre-concentrated propylene glycol monomethyl ether mixture outlet is connected with the preferential permeable organic membrane assembly through a first heat exchanger, and the preferential permeable organic membrane assembly is connected with the preferential permeable molecular sieve membrane assembly through a second heat exchanger. The utility model can realize the high-efficiency and high-purity recovery of propylene glycol monomethyl ether.
Description
Technical Field
The utility model relates to the technical field of propylene glycol monomethyl ether recovery, in particular to a membrane tower coupling device for recovering propylene glycol monomethyl ether, and more particularly relates to a membrane tower coupling device for efficiently recovering propylene glycol monomethyl ether from propylene oxide process wastewater.
Background
Propylene oxide is a high-end chemical raw material which is emphasized in China and encouraged to develop, and propylene is produced by adopting a propylene direct oxidation method, so that the method has the advantages of high atomic utilization rate and short process flow, meets the requirements of green chemistry and clean production, and becomes a new generation propylene oxide production process. In the process of producing propylene oxide by a direct oxidation method, the product is rich in byproducts such as propylene glycol monomethyl ether and the like besides propylene oxide. The traditional incineration and biochemical treatment has high cost and serious resource waste, and aggravates the CO of enterprises 2 Discharge pressure; the high added value chemicals in the wastewater are recycled, so that the economic benefit of the HPPO process can be remarkably improved.
In the separation and purification process of propylene oxide, substances such as methanol in wastewater are easy to remove and recycle, propylene glycol monomethyl ether is azeotropy generated by the propylene glycol monomethyl ether and water, the constant boiling point temperature is similar to the boiling point temperature of water, and the conventional rectification method (azeotropic rectification and benzene extraction rectification) has the problems of long process flow, large steam consumption, high energy consumption, complex operation, lower recovery rate of the propylene glycol monomethyl ether and the like. In addition, propylene glycol monomethyl ether is an excellent solvent and is widely applied to industries such as coating, printing and dyeing, electronic chemical industry and the like. Therefore, a novel and efficient propylene glycol monomethyl ether recovery technology is developed, and the method has important social and economic benefits.
Disclosure of Invention
Aiming at the prior art, the utility model provides a membrane tower coupling device for recovering propylene glycol monomethyl ether.
The utility model provides a film tower coupling device for recovering propylene glycol monomethyl ether, which comprises:
pretreatment of a rectifying tower; the pretreatment rectifying tower is provided with a propylene oxide waste liquid inlet, a pre-concentration propylene glycol monomethyl ether mixture outlet and a bottom material outlet; the bottom material outlet is connected with a tower bottom reboiler, a gas phase outlet of the tower bottom reboiler is connected with a pretreatment rectifying tower, and a liquid phase outlet of the tower bottom reboiler is connected with a cooler through a extraction pump and enters a bottom water extraction pipeline;
a double-membrane pervaporation dehydration system; the double-membrane pervaporation dehydration system comprises a preferential organic-permeable membrane assembly and a plurality of groups of preferential water-permeable molecular sieve membrane assemblies; the pre-concentrated propylene glycol monomethyl ether mixture outlet is connected with the preferential permeable organic membrane component through a first heat exchanger, and the preferential permeable organic membrane component is connected with the preferential permeable molecular sieve membrane component through a second heat exchanger; the gas phase outlet of the preferential permeable molecular sieve membrane component is respectively connected with a finished product tank and a compressor, and the compressor is connected with the pretreatment rectifying tower.
Through the design, the pre-concentrated propylene glycol monomethyl ether mixture is sent to the first heat exchanger for heating, then sent to the preferential organic membrane module, the propylene glycol monomethyl ether mixture is concentrated, and the propylene glycol monomethyl ether content in the material liquid concentrated on the downstream side of the preferential organic membrane module is controlled; and then the discharged liquid is sent to a second heat exchanger, heated and then enters a preferential permeable molecular sieve membrane module, and finally concentrated to obtain the propylene glycol monomethyl ether product with the mass fraction reaching the technological requirement.
In addition, part of the gas phase generated by the last stage of the membrane component of the double-membrane pervaporation dehydration system is conveyed to a compressor through a pipeline, is compressed and heated by the compressor, is conveyed to the pretreatment rectifying tower as a heat source, and is recovered after heat exchange in the pretreatment rectifying tower.
Preferably, the theoretical plate number of the pretreatment rectifying tower is 65-95, and the propylene oxide waste liquid inlet is arranged at the 15 th-45 th theoretical plate of the pretreatment rectifying tower.
Preferably, the preferential-permeation organic membrane component is made of a composite membrane, and the top layer of the composite membrane is made of a dense membrane material which preferentially passes through organic matters, and is preferentially made of polydimethylsiloxane.
Preferably, the preferential water permeable molecular sieve membrane component is made of a composite membrane, and the top layer of the composite membrane is made of a compact hydrophilic membrane material, and is preferably made of a Na-type molecular sieve membrane.
Preferably, the preferential water permeable molecular sieve membrane assemblies are arranged into 1-3 groups, and adjacent preferential water permeable molecular sieve membrane assemblies are connected in series.
Preferably, the waste liquid outlets of the preferential permeable organic membrane component and the preferential permeable molecular sieve membrane component are connected with a waste water tank.
Further preferably, the propylene glycol monomethyl ether content in the propylene oxide waste liquid to be treated is 1-18%.
Preferably, the tower top temperature of the pretreatment rectifying tower is 90-110 ℃, the tower bottom temperature is 105-118 ℃, and the mass reflux ratio is 3-7.
Preferably, the temperature of the feed liquid fed into the preferential organic membrane module after being heated by the first heat exchanger is 10-60 ℃, preferably 15-25 ℃; the osmotic pressure side pressure is 0.1 to 40kPa, preferably 0.3 to 10kPa.
Preferably, the temperature of the feed liquid fed into the preferential permeable molecular sieve membrane assembly after being heated by the second heat exchanger is 80-140 ℃, preferably 100-125 ℃; the osmotic pressure side pressure is 0.1 to 40kPa, preferably 0.3 to 10kPa.
Preferably, the inlet pressure of the compressor is normal pressure to 0.05MPa, and the outlet side pressure is 0.25 to 0.45MPa; the inlet temperature of the compressor is 75-90 ℃, and the outlet temperature of the compressor is 118-130 ℃.
Compared with the prior art, the utility model has the beneficial effects that:
1. according to the utility model, after the low-concentration propylene glycol monomethyl ether mixed solution is subjected to pretreatment rectification and double-membrane pervaporation dehydration treatment, the propylene glycol monomethyl ether content can reach 99.3-99.9%, so that the propylene glycol monomethyl ether is efficiently recovered in high purity.
2. In the utility model, the membrane separation technology is introduced to ensure that the third component is not required to be added in the dehydration process of the organic solvent, so that the pollution to the environment caused by the addition of the third component and the retreatment cost of the third component are saved, the energy consumption is reduced, and the product quality is improved.
3. The utility model introduces a vapor recompression technology, further greatly reduces fresh vapor consumption, and improves the energy utilization rate in the system, thereby truly realizing low-energy operation in the propylene glycol monomethyl ether recovery process.
4. The utility model has the advantages of safety, high efficiency, easy operation and the like, has positive significance on environmental protection, and can be used for recycling other types of low-concentration organic solvents.
Drawings
Fig. 1 is a schematic structural diagram of an embodiment of the present utility model.
In the figure: 1. pretreatment of a rectifying tower; 2. a bottom reboiler; 3. a production pump; 4. a cooler; 5. a first heat exchanger; 6. preferentially permeating the organic matter membrane component; 7. a second heat exchanger; 8. a first preferentially permeable molecular sieve membrane module; 9. a third heat exchanger; 10. a second preferentially permeable molecular sieve membrane module; 11. a waste water tank; 12. a finished product storage tank; 13. a compressor.
Detailed Description
The utility model is further described with reference to the following detailed drawings in order to make the technical means, the creation characteristics, the achievement of the purpose and the effect of the implementation of the utility model easy to understand.
Example 1
A membrane tower coupling device for recovering propylene glycol monomethyl ether, as shown in figure 1, comprises a pretreatment rectifying tower 1 and a double-membrane pervaporation dehydration system.
Wherein, the pretreatment rectifying tower 1 is provided with a propylene oxide waste liquid inlet, a pre-concentration propylene glycol monomethyl ether mixture outlet and a bottom material outlet; the bottom material outlet is connected with a tower bottom reboiler 2, a gas phase outlet of the tower bottom reboiler 2 is connected with a pretreatment rectifying tower 1, and a liquid phase outlet of the tower bottom reboiler 2 is connected with a cooler 4 through a extraction pump 3 and enters a bottom water extraction pipeline.
The double-membrane pervaporation dehydration system comprises a preferential organic matter membrane module 6 and two groups of preferential water permeable molecular sieve membrane modules, namely a first preferential water permeable molecular sieve membrane module 8 and a second preferential water permeable molecular sieve membrane module 10, wherein the first preferential water permeable molecular sieve membrane module 8 is connected with the second preferential water permeable molecular sieve membrane module 10 through a third heat exchanger 9; the pre-concentrated propylene glycol monomethyl ether mixture outlet is connected with a preferential organic-permeable membrane component 6 through a first heat exchanger 5, the preferential organic-permeable membrane component 6 is connected with a first preferential water-permeable molecular sieve membrane component 8 through a second heat exchanger 7, the gas phase outlet of a second preferential water-permeable molecular sieve membrane component 10 is respectively connected with a finished product tank 12 and a compressor 13, and the compressor 13 is connected with the pretreatment rectifying tower 1. The waste liquid outlets of the organic matter preferential permeation membrane component 6, the first water preferential permeation molecular sieve membrane component 8 and the second water preferential permeation molecular sieve membrane component 10 are all connected with a waste water tank 11.
The theoretical plate number of the pretreatment rectifying tower 1 is 75, and the propylene oxide waste liquid inlet is arranged at the 27 th theoretical plate of the pretreatment rectifying tower 1. The preferential organic-matter-permeable membrane component 1 is made of a composite membrane, and the top layer of the composite membrane is made of a dense membrane material which preferentially passes through organic matters and is made of polydimethylsiloxane. The first preferential water permeable molecular sieve membrane component 8 and the second preferential water permeable molecular sieve membrane component 10 are both made of composite membranes, and the top layer of the composite membranes is made of compact hydrophilic membrane materials and is made of Na-type molecular sieve membranes.
In this way, the pre-concentrated propylene glycol monomethyl ether mixture is sent to a first heat exchanger 5 for heating, then sent to a preferential organic membrane module 6, the propylene glycol monomethyl ether mixture is concentrated, and the propylene glycol monomethyl ether content in the material liquid concentrated on the downstream side of the preferential organic membrane module is controlled; and then the discharged liquid is sent into a second heat exchanger 7, heated and then enters a preferential permeable molecular sieve membrane module, and finally concentrated to obtain the propylene glycol monomethyl ether product with the mass fraction reaching the technological requirement.
In addition, a part of the gas phase generated by the second preferential permeable molecular sieve membrane module 10 is conveyed to the compressor 13 through a pipeline, is compressed and warmed by the compressor 13, is conveyed to the pretreatment rectifying tower 1 as a heat source, and is recovered after heat exchange in the pretreatment rectifying tower 1.
In the embodiment, the mass fraction of the propylene glycol monomethyl ether in the tower top material at the pre-concentrated propylene glycol monomethyl ether mixture outlet of the pre-treatment rectifying tower 1 can reach 32-45%, the mass fraction of the propylene glycol monomethyl ether in the material liquid discharged from the preferential organic matter-permeable membrane component 6 can reach 65-86%, and the mass fraction of the propylene glycol monomethyl ether finally obtained by concentration can reach 99.3-99.9%.
Example 2
On the basis of the membrane tower coupling device obtained in example 1, a propylene glycol monomethyl ether aqueous solution with a mass fraction of 1.73% was fed into the pretreatment rectifying tower 1, and parameters of the pretreatment rectifying tower 1 were set as follows: the tower top temperature is 100 ℃, the tower bottom temperature is 110 ℃, the mass reflux ratio is 5, and finally, the mass fraction of the tower top material of the pretreatment rectifying tower 1 is 33.1%.
The tower top material enters the preferential organic membrane module 6 after being heated by the first heat exchanger 5, the lateral pressure of the material passing through is 1kPa, the temperature is 30 ℃, and the flux is 1.2 kg/(m) 2 h) The material liquid on the membrane permeation side is separated by the preferential organic matter membrane component 6 to finally obtain the propylene glycol monomethyl ether with the mass fraction of 67.2 percent, and the material liquid after the propylene glycol monomethyl ether is removed in the preferential organic matter membrane component 6 is input into the wastewater tank 11 through a pipeline.
Propylene glycol monomethyl ether with lower concentration is heated by a second heat exchanger 7 and then sequentially concentrated into high concentration by a first priority permeable molecular sieve membrane assembly 8 and a second priority permeable molecular sieve membrane assembly 10, the permeation side pressure of the first priority permeable molecular sieve membrane assembly 8 is controlled to be 1kPa, the temperature is 125 ℃, and the flux is 1.8 kg/(m) 2 h) The method comprises the steps of carrying out a first treatment on the surface of the The permeate side pressure of the second preferential water permeable molecular sieve membrane module 10 was controlled to be 1.5kPa, the temperature was 125 ℃, and the flux was 2.1 kg/(m) 2 h) The method comprises the steps of carrying out a first treatment on the surface of the 99.7% (wt%)The materials after the propylene glycol monomethyl ether is removed in the first and second molecular sieve membrane modules 8 and 10 are respectively introduced into a wastewater tank 11 from the lower side of the module through a pipeline.
Part of the final material enters a compressor 13, the inlet pressure of the compressor 13 is normal pressure, the outlet side pressure is 0.3MPa, the inlet temperature is 80 ℃, the outlet temperature is 120 ℃, and the energy consumption is reduced by 15%.
The foregoing is only the embodiments of the present utility model, and therefore, the patent scope of the utility model is not limited thereto, and all equivalent structures made by the description of the utility model and the accompanying drawings are directly or indirectly applied to other related technical fields, which are all within the scope of the utility model.
Claims (6)
1. A membrane tower coupling apparatus for recovering propylene glycol monomethyl ether, comprising:
pretreatment of a rectifying tower; the pretreatment rectifying tower is provided with a propylene oxide waste liquid inlet, a pre-concentration propylene glycol monomethyl ether mixture outlet and a bottom material outlet; the bottom material outlet is connected with a tower bottom reboiler, a gas phase outlet of the tower bottom reboiler is connected with a pretreatment rectifying tower, and a liquid phase outlet of the tower bottom reboiler is connected with a cooler through a extraction pump and enters a bottom water extraction pipeline;
a double-membrane pervaporation dehydration system; the double-membrane pervaporation dehydration system comprises a preferential organic-permeable membrane assembly and a plurality of groups of preferential water-permeable molecular sieve membrane assemblies; the pre-concentrated propylene glycol monomethyl ether mixture outlet is connected with the preferential permeable organic membrane component through a first heat exchanger, and the preferential permeable organic membrane component is connected with the preferential permeable molecular sieve membrane component through a second heat exchanger; the gas phase outlet of the preferential permeable molecular sieve membrane component is respectively connected with a finished product tank and a compressor, and the compressor is connected with the pretreatment rectifying tower.
2. The membrane tower coupling device for recovering propylene glycol monomethyl ether as claimed in claim 1, wherein the theoretical plate number of said pretreatment rectifying tower is 65-95, and said propylene oxide waste liquid inlet is placed at 15-45 theoretical plates of said pretreatment rectifying tower.
3. The membrane tower coupling device for recovering propylene glycol monomethyl ether as claimed in claim 1 or 2, wherein said preferential-permeation organic-matter membrane module is made of a composite membrane, and the top layer of said composite membrane is made of polydimethylsiloxane.
4. The membrane tower coupling device for recovering propylene glycol monomethyl ether as claimed in claim 1 or 2, wherein said preferential water permeable molecular sieve membrane module is made of a composite membrane, and the top layer of said composite membrane is made of a Na molecular sieve membrane.
5. The membrane tower coupling device for recovering propylene glycol monomethyl ether according to claim 1 or 2, wherein the preferential water permeable molecular sieve membrane modules are arranged in 1 to 3 groups, and adjacent ones of the preferential water permeable molecular sieve membrane modules are connected in series.
6. The membrane tower coupling device for recovering propylene glycol monomethyl ether as claimed in claim 1 or 2, wherein the waste liquid outlets of the preferential organic membrane module and the preferential water permeable molecular sieve membrane module are both connected to a waste water tank.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223466608.2U CN219128328U (en) | 2022-12-22 | 2022-12-22 | Membrane tower coupling equipment for recycling propylene glycol monomethyl ether |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223466608.2U CN219128328U (en) | 2022-12-22 | 2022-12-22 | Membrane tower coupling equipment for recycling propylene glycol monomethyl ether |
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| CN219128328U true CN219128328U (en) | 2023-06-06 |
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| CN202223466608.2U Active CN219128328U (en) | 2022-12-22 | 2022-12-22 | Membrane tower coupling equipment for recycling propylene glycol monomethyl ether |
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