CN110330413B - Method for recovering propylene glycol monomethyl ether in alcohol ether aqueous solution material flow - Google Patents
Method for recovering propylene glycol monomethyl ether in alcohol ether aqueous solution material flow Download PDFInfo
- Publication number
- CN110330413B CN110330413B CN201910702319.1A CN201910702319A CN110330413B CN 110330413 B CN110330413 B CN 110330413B CN 201910702319 A CN201910702319 A CN 201910702319A CN 110330413 B CN110330413 B CN 110330413B
- Authority
- CN
- China
- Prior art keywords
- tower
- propylene glycol
- solvent
- material flow
- extraction
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/26—Treatment of water, waste water, or sewage by extraction
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
- C07C41/01—Preparation of ethers
- C07C41/34—Separation; Purification; Stabilisation; Use of additives
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
- C07C41/01—Preparation of ethers
- C07C41/34—Separation; Purification; Stabilisation; Use of additives
- C07C41/38—Separation; Purification; Stabilisation; Use of additives by liquid-liquid treatment
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2303/00—Specific treatment goals
- C02F2303/18—Removal of treatment agents after treatment
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention discloses a method for recovering propylene glycol monomethyl ether in an alcohol ether aqueous solution stream, which comprises the steps of extracting an alcohol ether aqueous solution stream to be recovered by using an extraction solvent stream to obtain a water phase stream and an oil phase stream, then carrying out solvent recovery treatment on the oil phase stream, and then carrying out dehydration treatment; the extraction solvent is an organic oxygen-containing compound. According to the technical scheme, the propylene glycol monomethyl ether in the alcohol ether aqueous solution material flow can be better recovered, the energy consumption is greatly reduced, the industrial application can be realized, the obtained propylene glycol methyl ether can meet the quality standard of 'HG/T3939-2007 industrial propylene glycol methyl ether', and the isomeric propylene glycol methyl ether can meet the relevant enterprise standard.
Description
Technical Field
The invention relates to a recovery method, in particular to a method for recovering propylene glycol monomethyl ether.
Background
The method for producing propylene oxide (HPPO) by directly epoxidizing propylene with hydrogen peroxide is a novel production technology, has simple process flow and environmental protection, and gradually replaces the traditional chlorohydrin method propylene oxide production process.
Propylene glycol monomethyl ether, comprising two isomers of propylene glycol methyl ether (PM, NBP: 120.1 ℃) and isomeric propylene glycol methyl ether (IPM, NBP: 129.5 ℃), which can form an azeotrope with water, wherein the azeotropic temperature of the propylene glycol methyl ether and the water at 1atm is 96.7 ℃, and the content of the propylene glycol methyl ether in the azeotrope is 51.8 wt%; the azeotropic temperature of the isomeric propylene glycol methyl ether and water at 1atm is 98.4 ℃, and the content of the isomeric propylene glycol methyl ether in the azeotrope is 40.3 wt%.
In the process of producing propylene oxide by epoxidizing propylene with hydrogen peroxide, besides producing propylene oxide as a main product, a small amount of propylene glycol methyl ether (PM), isomeric propylene glycol methyl ether (IPM), 1, 2-Propylene Glycol (PG), dipropylene glycol monomethyl ether (DPM) and other impurities are generated, wherein the propylene glycol methyl ether and the isomeric propylene glycol methyl ether are byproducts generated by the ring-opening reaction of the propylene oxide and methanol. Since the azeotropic point of propylene glycol monomethyl ether with water is higher than that of methanol, propylene glycol monomethyl ether will be concentrated into an aqueous alcohol ether solution in an amount of about 1.5 to 10 wt%.
Propylene glycol monomethyl ether is a universal solvent with excellent performance, is widely applied to the industries of coatings, printing, electronic chemicals, textiles and the like, can be used as a chemical intermediate, and has high economic value. Therefore, in order to improve the economy of the HPPO plant, it is necessary to recover propylene glycol monomethyl ether in an aqueous alcohol ether solution.
Because the propylene glycol monomethyl ether is azeotropic with water, the propylene glycol monomethyl ether product cannot be recovered from an alcohol ether aqueous solution material flow by a direct distillation method. Currently, the method of pervaporation, azeotropic distillation or combination of extraction and azeotropic distillation is mainly adopted to recover propylene glycol monomethyl ether in alcohol ether aqueous solution flow.
CN103342631B discloses a process for separating propylene glycol monomethyl ether aqueous solution by a double-membrane coupling technology, wherein the propylene glycol monomethyl ether aqueous solution with low concentration passes through a preferential permeable organic membrane component and a preferential permeable molecular sieve membrane component in turn, and is subjected to pervaporation to obtain the propylene glycol monomethyl ether aqueous solution with the mass fraction of 99.0-99.7%.
CN103183589 discloses a method for separating propylene glycol monomethyl ether aqueous solution by azeotropic distillation, the entrainer used is cyclohexanol, vapor at the top of the azeotropic distillation tower is condensed and phase-separated, the water phase is discharged, and the organic phase is recycled.
CN109251133 discloses a liquid-liquid extraction-azeotropic distillation mixing process for separating propylene glycol methyl ether and water, wherein an extractant is a mixture of 2-ethylhexanoic acid and chloroform, the process comprises the steps of extracting a propylene glycol methyl ether aqueous solution by using the extractant, conveying an extract phase to an azeotropic distillation tower for azeotropic distillation, removing water from the top of the azeotropic distillation tower through a phase separator, conveying a mixture of 2-ethylhexanoic acid and propylene glycol methyl ether in a tower bottom to a recovery tower, obtaining a propylene glycol methyl ether product from the top of the recovery tower, and recycling the 2-ethylhexanoic acid as the extractant in the tower bottom.
In the process of producing propylene oxide by using hydrogen peroxide to epoxidize propylene, the content of propylene glycol monomethyl ether in the obtained alcohol ether aqueous solution material flow is about 1.5-10 wt%, the content is low, and the amount of the alcohol ether aqueous solution to be treated is large, when the technical scheme of CN103342631 is adopted, the treatment amount is difficult to meet the requirement, the pervaporation technology is not mature, and the industrial production is difficult to realize. If the technical scheme of CN103183589 is adopted, not only all water in the alcohol ether aqueous solution needs to be distilled out from the top of the azeotropic distillation tower, but also a large amount of entrainer needs to be distilled out from the top of the azeotropic distillation tower, so that the energy consumption is huge, and the economic cost is not high. If the technical scheme of CN109251133 is adopted, the dosage of the extracting agent is very large, so that the chloroform amount distilled from the top of the azeotropic distillation tower is also very large, the energy consumption is also very high, and in addition, the raffinate phase also contains a small amount of chloroform and 2-ethylhexanoic acid, thereby causing the loss of the extracting agent.
Disclosure of Invention
In view of the defects of the prior art, the invention aims to provide a method for recovering propylene glycol monomethyl ether, which can better recover propylene glycol monomethyl ether in an alcohol ether aqueous solution stream by the technical scheme of the invention, not only greatly reduce energy consumption, but also can be applied to industry, the obtained propylene glycol methyl ether can meet the quality standard of propylene glycol methyl ether for HG/T3939-2007 industry, and the isomeric propylene glycol methyl ether can meet the related enterprise standards.
To achieve the above objects and other related objects, the present invention is achieved by the following technical solutions.
The invention provides a method for recovering propylene glycol monomethyl ether in an alcohol ether aqueous solution stream, which comprises the steps of extracting an alcohol ether aqueous solution stream to be recovered by using an extraction solvent stream to obtain a water phase stream and an oil phase stream, then carrying out solvent recovery treatment on the oil phase stream, and then carrying out dehydration treatment; the extraction solvent is an organic oxygen-containing compound.
The alcohol ether aqueous solution stream to be recovered in the present application may be from any process that produces an aqueous alcohol ether solution, and it is necessary to recover propylene glycol monomethyl ether therefrom. Namely, the alcohol ether aqueous solution stream to be recovered can be an aqueous solution containing propylene glycol methyl ether or/and isomeric propylene glycol methyl ether, and preferably, the alcohol ether aqueous solution stream to be recovered contains 1.5 wt% -45 wt% of propylene glycol methyl ether and/or isomeric propylene glycol methyl ether. Usually, in the process of producing propylene oxide by directly epoxidizing propylene with hydrogen peroxide, a stream of alcohol ether aqueous solution is generated in the tower bottom of a methanol rectifying tower, wherein the content of propylene glycol monomethyl ether is about 1.5-10 wt%, and the stream also contains a small amount of methanol, ethanol, n-propanol, isopropanol, acetone, butanone, 1, 2-Propylene Glycol (PG), dipropylene glycol monomethyl ether (DPM) and the like besides water and propylene glycol monomethyl ether.
According to the invention, the extraction process is carried out in an extraction column (T101), and the aqueous alcohol ether solution stream to be recovered and the extraction solvent stream are countercurrently contacted in the extraction column (T101).
According to the invention, the mass flow and the relative flow of each material flow can be determined and selected according to the conventional operation in the field in the whole operation process, and generally, the ratio of the mass flow of the extraction solvent material flow to the total mass flow of propylene glycol methyl ether and isomeric propylene glycol methyl ether in the alcohol ether water solution material flow to be recovered is (6-100): 1.
According to the invention, propylene glycol monomethyl ether in an aqueous alcohol ether stream is first extracted into an extraction solvent in an extraction column. Experimental studies show that the higher the extraction temperature, the larger the distribution coefficient of propylene glycol monomethyl ether in the extraction solvent, the more beneficial the extraction process of propylene glycol monomethyl ether, but the higher the temperature, the greater the solubility of the extraction solvent in water, the higher the water content in the extract, i.e., the oil phase stream, and the adverse effect on the subsequent dehydration operation. To solve this problem, the extraction process can be carried out at a relatively high temperature, e.g. 95 ℃ to 125 ℃, then the temperature of the extract phase, i.e. the oil phase stream, is cooled to a temperature below 45 ℃, e.g. 2 ℃ to 45 ℃, then the separated free water is removed by a coalescer and the removed free water stream is returned to the upper part of the extraction column, and the cooled oil phase stream from which the separated free water is removed is fed to the dehydration column.
According to the invention, the extraction solvent plays a very critical role in the technical solution of the invention, in which organic oxygen-containing compounds are selected as the extraction solvent.
Because the content of the propylene glycol monomethyl ether in the alcohol ether aqueous solution material flow is low, the dosage of the extraction solvent is very large for ensuring the recovery rate of the propylene glycol monomethyl ether, and the extraction solvent is required to be recovered from a tower kettle in a solvent recovery tower for saving energy consumption, so that the boiling point of the extraction solvent is required to be higher than the boiling point (NBP: 129.5 ℃) of the isomeric propylene glycol methyl ether. The solvent recovery treatment is to perform clear cutting of the extraction solvent and propylene glycol monomethyl ether in the oil phase stream in a solvent recovery column (T201), and the recovered extraction solvent stream is obtained from the bottom of the solvent recovery column. Preferably, one or more of the following features are included: recycling a stream discharged from the bottom of the solvent recovery column (T201) as an extraction solvent; a part of the tower bottom discharge material flow of the solvent recovery tower (T201) is regenerated by the solvent to obtain a regenerated solvent material flow which is recycled as the extraction solvent; in the solvent regeneration, heavy components extracted into the oil phase material flow are removed in a solvent regeneration tower (T202), a regenerated solvent material flow is obtained from the top of the tower, and the heavy component material flow at the bottom of the tower is discharged out of the system.
According to the present invention, the extraction solvent is required to be recycled, and the extraction solvent contains a less stable ether bond, carbonyl group or hydroxyl group, and in order to protect the extraction solvent and prevent the extraction solvent from being deteriorated during recycling, the solvent recovery column is preferably operated under a vacuum at a relatively low pressure and temperature, for example, an absolute pressure of 4KPa to 140KPa (preferably 6KPa to 25KP, and an operation temperature of 29 ℃ to 181 ℃, preferably 38 ℃ to 122 ℃).
According to the invention, because the alcohol ether aqueous solution stream may contain propylene glycol, dipropylene glycol monomethyl ether and other heavy components besides propylene glycol monomethyl ether and water, experimental research shows that the extraction solvent has a large distribution coefficient to dipropylene glycol monomethyl ether, when the alcohol ether aqueous solution stream contains propylene glycol, dipropylene glycol monomethyl ether and other heavy components, the oil phase stream is inevitably mixed with propylene glycol, dipropylene glycol monomethyl ether and other heavy components, in order to prevent the heavy components from accumulating in the extraction solvent, a part of the recovered extraction solvent stream needs to be separated into a solvent regeneration tower, the regenerated solvent is evaporated from the tower top and recycled as the extraction solvent, and the heavy components are discharged from the tower bottom. Because the heavy component has a high boiling point and contains active groups such as hydroxyl groups and the like, the solvent regeneration tower is preferably rectified in vacuum to reduce the temperature of a tower kettle, if the absolute operating pressure is 6KPa-25KPa, the operating temperature is 85-146 ℃.
According to the invention, the main function of the dehydration tower is to remove the water in the overhead stream of the solvent recovery tower, and in order to ensure that the water content in the propylene glycol methyl ether product stream can meet the quality requirement of HG/T3939-2007 propylene glycol methyl ether for industrial use, the water content in the bottom stream of the dehydration tower is preferably less than 400ppmw, and preferably less than 50 ppmw. Since the overhead dehydrated stream contains a large amount of propylene glycol monomethyl ether, the stream is returned to the upper part of the extraction column to recover the propylene glycol monomethyl ether. When the alcohol ether aqueous solution stream to be recovered contains light components, such as methanol, ethanol, n-propanol, isopropanol, acetone, butanone and the like, in order to prevent the components from accumulating in the system, the dehydrated stream at the top of the dehydrating tower needs to be discharged to remove the light components, such as a methanol rectifying tower in a device for directly epoxidizing propylene to produce propylene oxide by removing hydrogen peroxide, wherein propylene glycol monomethyl ether returns the alcohol ether aqueous solution stream at the bottom of the methanol rectifying tower to the extraction tower, or the discharged part returns to a light component removal tower which is separately arranged, and the stream after removing the light components returns to the upper part of the extraction tower. If methanol, ethanol, normal propyl alcohol, isopropyl alcohol, acetone, butanone and the like do not generate accumulated light components in the system in the alcohol ether water solution material flow to be recovered, the dehydration material flow at the top of the dehydration tower can be directly and completely returned to the upper part of the extraction tower.
If the stream discharged from the bottom of the dehydrating tower contains both propylene glycol methyl ether (PM) and isomeric propylene glycol methyl ether (IPM), preferably, the method further comprises the step of rectifying and separating the propylene glycol methyl ether and the isomeric propylene glycol methyl ether by using a propylene glycol methyl ether rectifying tower (T401) on the stream discharged from the bottom of the dehydrating tower. According to the present invention, the propylene glycol methyl ether rectification column and the isomeric propylene glycol methyl ether rectification column may be operated according to conventional operations in the art, provided that the propylene glycol methyl ether content of the propylene glycol methyl ether product stream is greater than 99.5 wt%, preferably greater than 99.8 wt%. Particularly, if only one component of propylene glycol methyl ether or isomeric propylene glycol methyl ether is contained in the alcohol ether aqueous solution stream to be recovered besides water, the corresponding product stream can be directly obtained from the tower bottom stream of the dehydration tower.
According to the invention, since the extraction solvent also has a certain amount of solubility in the aqueous phase stream, i.e. the aqueous phase stream discharged from the bottom of the extraction column also contains a small amount of extraction solvent, in order to recover the extraction solvent and reduce the loss of the extraction solvent, the aqueous phase stream is introduced into the solvent stripping column, and the extraction solvent is recovered from the top of the column. In order to prevent the extraction solvent from entering the bottom of the solvent stripper, which causes the loss of the extraction solvent, it is required that the extraction solvent must form a minimum azeotrope with water so that the extraction solvent dissolved in the aqueous stream can be distilled off from the top of the solvent stripper. Preferably, one or more of the following features are included: stripping the aqueous phase material flow discharged from the tower bottom of the extraction tower to recover the extraction solvent; the solvent stripping treatment is carried out in a solvent stripping tower (T102), the steam at the top of the tower is subjected to phase splitting after condensation to obtain a stripped oil phase material flow and a stripped water phase material flow, the stripped water phase material flow returns to the solvent stripping tower, the stripped oil phase material flow is circularly used as an extraction solvent, and a wastewater material flow is discharged from the tower bottom of the solvent stripping tower (T102).
In addition, the extraction solvent is required to have a large partition coefficient for propylene glycol monomethyl ether to reduce the amount of extraction solvent used, and to have a solubility in water as low as possible to reduce the amount of recycle of the dehydrated stream. The organic oxygen-containing compound is selected from diisobutyl ketone (DIBK), Isobutyl Acetone (IAMK), 4, 6-dimethyl-2-heptanone (IDIBK), 1, 3-dimethylbutanol (MIBC), diisobutyl carbinol (DIBC), and the like, and mixtures thereof, taking into account the polarity, physicochemical properties, cost, and source of the organic oxygen-containing compound.
According to the invention, because the energy consumption for recovering propylene glycol monomethyl ether from the alcohol ether aqueous solution material flow is large, in order to reduce the energy consumption, the rectifying tower in the technical scheme can be thermally integrated with a rectifying tower outside the technical scheme, for example, a methanol rectifying tower in the production of propylene oxide by directly epoxidizing propylene with hydrogen peroxide is thermally integrated, or the internal part of the rectifying tower in the technical scheme is thermally integrated, which shall not influence the protection scope of the invention.
Compared with the prior art for recovering propylene glycol monomethyl ether by pervaporation, azeotropic distillation or extraction-azeotropic distillation mixed technology, the invention achieves obvious technical progress, and concretely comprises the following aspects:
1. the invention adopts the conventional chemical unit operation processes such as extraction, rectification and the like, has mature and reliable technology and is suitable for industrial mass production;
2. when the content of propylene glycol monomethyl ether in the alcohol ether aqueous solution is low, the energy consumption of the azeotropic distillation or the extraction-azeotropic distillation mixed process is very high, only a small amount of water dissolved in the extraction solvent needs to be distilled out, the boiling point of the extraction solvent is higher than that of propylene glycol methyl ether, the extraction solvent is mainly recovered from a tower kettle of a solvent recovery tower in a liquid state form, and the extraction solvent does not need to be distilled out from the top of the solvent recovery tower, so that the latent heat of solvent vaporization is saved, and the energy-saving effect is obvious;
3. the extraction solvent used in the invention can form the lowest azeotrope with water, so the extraction solvent can not enter the wastewater stream at the bottom of the solvent stripping tower, and the extraction solvent is hardly lost in the using process;
4. when the propylene glycol monomethyl ether in the alcohol ether aqueous solution material flow is recovered, light components such as methanol and ethanol and heavy components such as dipropylene glycol monomethyl ether in the alcohol ether aqueous solution material flow to be recovered are basically removed, and the propylene glycol component is mainly left in the wastewater material flow discharged from the solvent stripping tower kettle, so that the difficulty of recovering the propylene glycol from the material flow is reduced;
5. the recovery rate of the propylene glycol monomethyl ether is very high and can reach more than 99 percent, more propylene glycol monomethyl ether products can be recovered, and the COD value of the waste water material flow discharged from the bottom of the solvent stripping tower can be reduced, so that the difficulty in treating the waste water of the material flow is reduced;
6. the purity of the propylene glycol methyl ether product obtained by the method can reach more than 99.8 percent, the quality requirement of HG/T3939-2007 industrial propylene glycol methyl ether is met, and the obtained isomeric propylene glycol methyl ether product can meet the relevant enterprise standard.
Drawings
Embodiments of the invention are described below with reference to the accompanying drawings, in which:
FIG. 1 is a schematic view of a first process flow of the present invention;
FIG. 2 is a schematic view of a second process of the present invention.
In the drawings, like equipment and streams are denoted by like reference numerals, wherein the reference numerals particularly denote the following:
t101-extraction tower, T102-solvent stripping tower, T201-solvent recovery tower, T202-solvent regeneration tower, T301-dehydration tower and T401-rectification tower; e101-oil phase stream cooler; v101-coalescer, V102-solvent stripper reflux drum.
101-a stream of an aqueous alcohol ether solution to be recovered, 102-a supplemented solvent stream, 103-an oil phase stream, 104-a cooled oil phase stream, 105-a coalesced dehydrated oil phase stream, 106-a coalesced dehydrated stream, 107-an aqueous phase stream, 108-solvent stripper overhead steam, 109-a stripped aqueous phase stream, 110-a stripped oil phase stream, 111-a wastewater stream, 201-a stream containing propylene glycol methyl ether, isomeric propylene glycol methyl ether, water and the like, 202-a recovered solvent stream, 203-a recovered solvent stream of an extraction column, 204-a recovered solvent stream of a desolventizing regeneration column, 205-a regenerated solvent stream, 206-a heavy component stream, 207-an extraction solvent stream, 301-a dehydrated stream, 302-a stream containing propylene glycol methyl ether, isomeric propylene glycol and the like and having water removed, a 401-propylene glycol methyl ether product stream, and a 402-isomeric propylene glycol methyl ether product stream.
Detailed Description
The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure.
Before the present embodiments are further described, it is to be understood that the scope of the invention is not limited to the particular embodiments described below; it is also to be understood that the terminology used in the examples is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention. Test methods in which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under conditions recommended by the respective manufacturers.
When numerical ranges are given in the examples, it is understood that both endpoints of each of the numerical ranges and any value therebetween can be selected unless the invention otherwise indicated. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In addition to the specific methods, devices, and materials used in the examples, any methods, devices, and materials similar or equivalent to those described in the examples may be used in the practice of the invention in addition to the specific methods, devices, and materials used in the examples, in keeping with the knowledge of one skilled in the art and with the description of the invention.
Example 1
The technological process is shown in figure 1, the extraction solvent is diisobutyl ketone (DIBK) and is used for treating alcohol ether aqueous solution material flow 101 discharged from a device for producing propylene oxide by epoxidizing propylene with hydrogen peroxide, the material flow comprises water, propylene glycol methyl ether (PM) and isomeric propylene glycol methyl ether (IPM), and also comprises a small amount of methanol, ethanol, propanol, Propylene Glycol (PG) and dipropylene glycol monomethyl ether (DPM), the material flow enters the upper part of an extraction tower T101, an extraction solvent material flow 207 enters the lower part of the extraction tower, the two are in countercurrent contact in the extraction tower to complete the extraction process, the operation temperature of the extraction tower is 100.5-104.6 ℃, an oil phase overhead material flow 103 enters an oil phase material flow cooler E101 and enters a coalescer V101 after being cooled to 40 ℃, a coalescence dehydration material flow 106 returns to the upper part of the extraction tower to coalesce, and the dehydrated oil phase material flow 105 enters a solvent recovery tower T201. The aqueous phase stream 107 at the bottom of the extraction tower enters a solvent stripping tower T102, the steam 108 at the top of the solvent stripping tower enters a reflux tank V102 for phase separation after being condensed, wherein the stripped aqueous phase stream 109 returns to the solvent stripping tower, and the stripped oil phase stream 110 returns to the lower part of the extraction tower. The operation absolute pressure of the solvent recovery tower T201 is 9KPa to 16KPa, the operation temperature is 53 ℃ to 110 ℃, a material flow 201 containing propylene glycol methyl ether, isomeric propylene glycol methyl ether, water and the like is obtained from the tower top and then enters a dehydration tower T301, a recovered solvent material flow 202 obtained from the tower bottom is then divided into two parts, one part 203 is directly recycled to the lower part of the extraction tower, and the other part 204 is sent to a solvent regeneration tower T202. The operation absolute pressure of the solvent regeneration tower T202 is 6KPa-13KPa, the operation temperature is 92-129 ℃, the regenerated solvent stream 205 obtained from the tower top is circularly returned to the lower part of the extraction tower, and the heavy component stream 206 in the tower kettle is discharged out of the system. A dehydrated material flow 301 is obtained from the top of the dehydrating tower and returns to the lower part of the extraction tower, and a material flow 302 which contains propylene glycol methyl ether, isomeric propylene glycol methyl ether and is dehydrated is obtained from the bottom of the dehydrating tower and then enters a rectifying tower T401. In a propylene glycol methyl ether rectifying tower, a propylene glycol methyl ether product material flow 401 is obtained from the top of the tower, and an isomeric propylene glycol methyl ether product material flow 402 is obtained from the bottom of the tower. The mass balance of the process is shown in table 1.
Table 1 example 1 material balance table
Example 2
The process flow is shown in figure 2, the extraction solvent is diisobutyl carbinol (DIBC) and is used for treating an alcohol ether aqueous solution material flow 101 discharged by a certain device, the material flow only comprises water and isomeric propylene glycol methyl ether (IPM), the material flow enters the upper part of an extraction tower T101, an extraction solvent material flow 207 enters the lower part of the extraction tower, the two materials are in countercurrent contact in the extraction tower to finish the extraction process, the operation temperature of the extraction tower is 114-. The aqueous phase material flow 107 at the bottom of the extraction tower enters a solvent stripping tower T102, the steam 108 at the top of the solvent stripping tower enters a reflux tank V102 for phase separation after being condensed, wherein the stripped aqueous phase material flow 109 returns to the solvent stripping tower, and the stripped oil phase material flow 110 returns to the lower part of the extraction tower. The absolute pressure of the solvent recovery tower T201 is 16KPa to 25KPa, the operation temperature is 56 ℃ to 121 ℃, a material flow 201 containing isomeric propylene glycol methyl ether and water is obtained from the top of the solvent recovery tower T201 and then enters a dehydration tower T301, and a recovered solvent material flow 202 obtained from the bottom of the tower is directly recycled to the lower part of the extraction tower. And obtaining a dehydrated material flow 301 from the top of the dehydrating tower and returning the dehydrated material flow to the lower part of the extraction tower, and obtaining an isomeric propylene glycol methyl ether product flow from the bottom of the dehydrating tower. The mass balance table for this process is shown in table 2.
Table 2 example 2 material balance table
Example 3
The technological process is shown in figure 2, the extraction solvent is a mixture of diisobutyl ketone (DIBK), 4, 6-dimethyl-2-heptanone (IDIBK), 1, 3-dimethyl butanol (MIBC) and diisobutyl carbinol (DIBC) and is used for treating an alcohol ether aqueous solution material flow 101 discharged from a device, the material flow only comprises water and propylene glycol methyl ether (PM), the material flow enters the upper part of an extraction tower T101, an extraction solvent material flow 207 enters the lower part of the extraction tower and is in countercurrent contact in the extraction tower to complete the extraction process, the operation temperature of the extraction tower is 100-108 ℃, an oil phase material flow 103 at the top of the tower enters an oil phase material flow cooler E101 and enters a coalescer V101 after being cooled to 40 ℃, a coalesced and dehydrated material flow 106 returns to the upper part of the extraction tower, and the oil phase material flow 105 after being coalesced and dehydrated enters a solvent recovery tower T201. The aqueous phase material flow 107 at the bottom of the extraction tower enters a solvent stripping tower T102, the steam 108 at the top of the solvent stripping tower enters a reflux tank V102 for phase separation after being condensed, wherein the stripped aqueous phase material flow 109 returns to the solvent stripping tower, and the stripped oil phase material flow 110 returns to the lower part of the extraction tower. The operation absolute pressure of the solvent recovery tower T201 is 9KPa to 16KPa, the operation temperature is 57 ℃ to 109 ℃, a material flow 201 containing propylene glycol methyl ether and water is obtained from the tower top and then enters a dehydration tower T301, and a recovered solvent material flow 202 obtained from the tower bottom is directly recycled to the lower part of the extraction tower. A dehydrated material flow 301 is obtained from the top of the dehydrating tower and returned to the lower part of the extraction tower, and a propylene glycol methyl ether product flow is obtained from the bottom of the dehydrating tower. The mass balance table for this process is shown in table 3.
Table 3 example 3 material balance table
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.
Claims (10)
1. A method for recovering propylene glycol monomethyl ether in an alcohol ether aqueous solution stream is characterized in that the alcohol ether aqueous solution stream to be recovered is extracted by an extraction solvent stream to obtain a water phase stream and an oil phase stream, then the solvent recovery treatment is carried out on the oil phase stream, and then the dehydration treatment is carried out; the extraction solvent is an organic oxygen-containing compound; the dehydration treatment is to carry out rectification dehydration on the material flow discharged from the tower top of the solvent recovery tower in a dehydration tower, the material flow containing water is discharged from the tower top of the dehydration tower, and the material flow containing propylene glycol monomethyl ether is obtained from the tower bottom of the dehydration tower; the extraction solvent and water form a minimum azeotrope; the extraction solvent is selected from one or more of diisobutyl ketone, isobutyl acetone, 4, 6-dimethyl-2-heptanone, 1, 3-dimethylbutanol and diisobutyl carbinol.
2. The method of claim 1, comprising one or more of the following features:
the extraction process is carried out in an extraction tower, and the alcohol ether aqueous solution material flow to be recovered and the extraction solvent material flow are in countercurrent contact in the extraction tower;
the ratio of the mass flow of the extraction solvent material flow to the total mass flow of propylene glycol methyl ether and isomeric propylene glycol methyl ether in the alcohol ether water solution material flow to be recovered is (6-100): 1;
the temperature of the extraction process is 95-125 ℃;
before the oil phase material flow is subjected to solvent recovery treatment, cooling the oil phase material flow and removing separated free water;
the alcohol ether aqueous solution stream to be recovered is an aqueous solution stream containing propylene glycol methyl ether or/and isomeric propylene glycol methyl ether;
in the alcohol ether water solution material flow to be recovered, the total content of propylene glycol methyl ether or/and isomeric propylene glycol methyl ether is 1.5-45 wt%;
the method also comprises the step of rectifying and separating propylene glycol methyl ether and isomeric propylene glycol methyl ether from tower bottom material flow obtained by dehydration treatment by using a rectifying tower.
3. The method of claim 2, comprising one or both of the following features:
cooling the oil phase stream to below 45 ℃;
the separated free water stream is removed for further extraction.
4. The method of claim 1, comprising one or more of the following features;
the boiling point of the extraction solvent is higher than that of isomeric propylene glycol methyl ether;
the solvent recovery treatment is to cut the extraction solvent and propylene glycol monomethyl ether in the oil phase material flow in a solvent recovery tower, and the recovered extraction solvent material flow is obtained from the bottom of the solvent recovery tower.
5. The method of claim 4, comprising one or more of the following features:
recycling the material flow discharged from the tower bottom of the solvent recovery tower as an extraction solvent;
a part of the tower bottom discharge material flow of the solvent recovery tower is subjected to solvent regeneration to obtain a regenerated solvent material flow which is recycled as the extraction solvent;
the absolute operating pressure of the solvent recovery tower is 4KPa to 140 KPa;
the operating temperature of the solvent recovery tower is 29-181 ℃.
6. The method of claim 5, comprising one or more of the following features:
in the solvent regeneration, heavy components extracted into the oil phase material flow are removed in a solvent regeneration tower, a regenerated solvent material flow is obtained from the tower top, and the heavy component material flow at the tower bottom is discharged out of the system;
the absolute pressure of the solvent regeneration tower is 6KPa to 25 KPa;
the operating temperature of the solvent regeneration tower is 85-146 ℃;
the operating temperature of the solvent recovery tower is 38-122 ℃.
7. The method of claim 2, comprising one or more of the following features:
returning the material flow obtained from the top of the dehydrating tower to the upper part of the extraction tower for extracting and recovering propylene glycol monomethyl ether;
removing light components from one part of the material flow obtained at the top of the dehydrating tower, and returning the light components to the upper part of the extraction tower for extracting and recovering propylene glycol monomethyl ether, wherein the light components comprise one or more selected from methanol, ethanol, n-propanol, isopropanol, acetone and butanone;
the mass content of water in the stream containing propylene glycol monomethyl ether obtained from the bottom of the dehydration tower is less than 400 ppm.
8. The method of claim 7, wherein the mass moisture content of the stream comprising propylene glycol monomethyl ether obtained from the bottom of the dehydration column is less than 50 ppm.
9. The process of claim 1, wherein the aqueous phase stream is subjected to a solvent stripping treatment to recover the extraction solvent.
10. The process of claim 9, wherein the solvent stripping process is carried out in a solvent stripper column, the overhead vapor is condensed and phase separated to provide a stripped oil phase stream and a stripped water phase stream, the stripped water phase stream is returned to the solvent stripper column, and the stripped oil phase stream is recycled for use as the extraction solvent.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910702319.1A CN110330413B (en) | 2019-07-31 | 2019-07-31 | Method for recovering propylene glycol monomethyl ether in alcohol ether aqueous solution material flow |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910702319.1A CN110330413B (en) | 2019-07-31 | 2019-07-31 | Method for recovering propylene glycol monomethyl ether in alcohol ether aqueous solution material flow |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110330413A CN110330413A (en) | 2019-10-15 |
| CN110330413B true CN110330413B (en) | 2022-08-09 |
Family
ID=68148202
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910702319.1A Active CN110330413B (en) | 2019-07-31 | 2019-07-31 | Method for recovering propylene glycol monomethyl ether in alcohol ether aqueous solution material flow |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110330413B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110606799B (en) * | 2019-10-31 | 2024-04-26 | 胜帮科技股份有限公司 | System and method for recycling byproduct of propylene oxide production by HPPO method |
| EP3892349A1 (en) | 2020-04-06 | 2021-10-13 | Evonik Operations GmbH | Process and facility for recovering methoxypropanols from an aqueous stream |
Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1633424A (en) * | 2002-02-15 | 2005-06-29 | 住友化学工业株式会社 | Method of purifying propylene oxide |
| CN103183589A (en) * | 2011-12-28 | 2013-07-03 | 上海交通大学 | Method for separating water and propylene glycol monomethyl ether |
| CN103342631A (en) * | 2013-07-09 | 2013-10-09 | 南京工业大学 | Process for separating propylene glycol monomethyl ether aqueous solution by using double membrane coupling technology |
| CN104974023A (en) * | 2015-06-11 | 2015-10-14 | 湖南海利株洲精细化工有限公司 | Method for recovering ethylene glycol monomethyl ether |
| CN105037071A (en) * | 2015-06-11 | 2015-11-11 | 济南大学 | Method for continuous extraction distillation separation of methylbenzene-propylene glycol monomethyl ether azeotropic mixture |
| CN106748619A (en) * | 2016-12-15 | 2017-05-31 | 惠生工程（中国）有限公司 | A kind of technique that propane is refined from the feed stream comprising propane and dimethyl ether |
| CN107032966A (en) * | 2017-06-14 | 2017-08-11 | 青岛科技大学 | A kind of method of liquid-liquid extraction separation of extractive distillation methyl proxitol and water |
| CN107721829A (en) * | 2016-08-12 | 2018-02-23 | 惠生工程（中国）有限公司 | A kind of method that dimethyl ether is removed from the feed stream comprising propane and dimethyl ether |
| CN109251133A (en) * | 2018-09-17 | 2019-01-22 | 青岛科技大学 | A kind of liquid-liquid extraction-azeotropic distillation hybrid technique of separating propylene glycol methyl ether and water |
| CN109851589A (en) * | 2017-11-30 | 2019-06-07 | 中国石油化工股份有限公司 | Oxide purification process and purification devices |
| CN109851588A (en) * | 2017-11-30 | 2019-06-07 | 中国石油化工股份有限公司 | The refining methd of propylene oxide |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8389750B2 (en) * | 2010-09-28 | 2013-03-05 | Lyondell Chemical Technology, L.P. | Purification of propylene oxide |
-
2019
- 2019-07-31 CN CN201910702319.1A patent/CN110330413B/en active Active
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1633424A (en) * | 2002-02-15 | 2005-06-29 | 住友化学工业株式会社 | Method of purifying propylene oxide |
| CN103183589A (en) * | 2011-12-28 | 2013-07-03 | 上海交通大学 | Method for separating water and propylene glycol monomethyl ether |
| CN103342631A (en) * | 2013-07-09 | 2013-10-09 | 南京工业大学 | Process for separating propylene glycol monomethyl ether aqueous solution by using double membrane coupling technology |
| CN104974023A (en) * | 2015-06-11 | 2015-10-14 | 湖南海利株洲精细化工有限公司 | Method for recovering ethylene glycol monomethyl ether |
| CN105037071A (en) * | 2015-06-11 | 2015-11-11 | 济南大学 | Method for continuous extraction distillation separation of methylbenzene-propylene glycol monomethyl ether azeotropic mixture |
| CN107721829A (en) * | 2016-08-12 | 2018-02-23 | 惠生工程（中国）有限公司 | A kind of method that dimethyl ether is removed from the feed stream comprising propane and dimethyl ether |
| CN106748619A (en) * | 2016-12-15 | 2017-05-31 | 惠生工程（中国）有限公司 | A kind of technique that propane is refined from the feed stream comprising propane and dimethyl ether |
| CN107032966A (en) * | 2017-06-14 | 2017-08-11 | 青岛科技大学 | A kind of method of liquid-liquid extraction separation of extractive distillation methyl proxitol and water |
| CN109851589A (en) * | 2017-11-30 | 2019-06-07 | 中国石油化工股份有限公司 | Oxide purification process and purification devices |
| CN109851588A (en) * | 2017-11-30 | 2019-06-07 | 中国石油化工股份有限公司 | The refining methd of propylene oxide |
| CN109251133A (en) * | 2018-09-17 | 2019-01-22 | 青岛科技大学 | A kind of liquid-liquid extraction-azeotropic distillation hybrid technique of separating propylene glycol methyl ether and water |
Non-Patent Citations (1)
| Title |
|---|
| 分离丙二醇甲基醚与水共沸物的过程综合与控制策略;赵婷然;《中国优秀硕士学位论文全文数据库工程科技Ⅰ辑》;20181231;第3.1.2节、图3.4、第47页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110330413A (en) | 2019-10-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110272333B (en) | Method for recovering propylene glycol monomethyl ether | |
| CN104109137B (en) | Oxide purification process | |
| CN101058541B (en) | Method for recovering triethylamine in water | |
| CN110330413B (en) | Method for recovering propylene glycol monomethyl ether in alcohol ether aqueous solution material flow | |
| CN105330514B (en) | A kind of purifying technique of synthesis gas preparing ethylene glycol | |
| CN101074211B (en) | Process for treating high-purity pyridine solution | |
| CN109851586B (en) | Process for purifying propylene oxide | |
| CN102432453A (en) | Process and equipment for purifying dilute acetic acid solution | |
| CN105254532B (en) | A kind of method of three tower variable-pressure rectification separating acetonitrile methyl alcohol-benzene ternary azeotrope | |
| CN102633597B (en) | Process of recovering ethanol, propyl alcohol and isobutyl alcohol from polyalcohol-water mixture | |
| CN105272819B (en) | The methanol purification process of the impurity containing ethyl acetate | |
| CN112142563A (en) | Purification method of isopropanol | |
| CN114315522B (en) | Purification method of cyclohexanol and preparation method of cyclohexanone | |
| CN100447120C (en) | Technological process for refining trimethylolpropane | |
| CN104447198B (en) | Separation technology for preparation of isopropanol by acetone hydrogenation | |
| KR101164900B1 (en) | Removal of propylene glycol and/or propylene glycol ethers from aqueous streams | |
| CN106117120A (en) | A kind of rectification water vapour penetration coupled method reclaims technique and the device of pyridine | |
| MXPA02000788A (en) | A method for the separation of and purification of an aqueous mixture consisting of the main components acetic acid and formic acid. | |
| EP3719008A1 (en) | Alkylene oxide production method and production system | |
| JPH0580458B2 (en) | ||
| CN109851582A (en) | The purification process of propylene oxide | |
| CN104693005A (en) | New process for separating methanol-propyl formate azeotrope through extractive distillation | |
| CN106866409B (en) | Method for extracting and recovering dilute acetic acid from cyclohexyl acetate | |
| CN109851588B (en) | Method for purifying propylene oxide | |
| CN110683696A (en) | Method and device for recovering N-alkyl morpholine from morpholine wastewater |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |