Title of Invention: Continuous purification system for esterification reaction products
technical field
[One]
Cross-Citation with Related Applications
[2]
This application claims the benefit of priority based on Korean Patent Application No. 10-2019-0039718 dated April 4, 2019, and all contents disclosed in the literature of the Korean patent application are incorporated as a part of this specification.
[3]
technical field
[4]
The present invention relates to a system for the continuous purification of an esterification reaction product.
background
[5]
Phthalate-based plasticizers account for 92% of the global plasticizer market (Mustafizur Rahman and Christopher S. Brazel "The plasticizer market: an assessment of traditional plasticizers and research trends to meet new challenges" Progress in Polymer Science 2004, 29, 1223-1248 Note), it is an additive mainly used to impart flexibility, durability, and cold resistance to polyvinyl chloride (hereinafter referred to as PVC) and to improve processability by lowering the viscosity when melting. From hard products to soft products that are soft and stretchable and can be used for food packaging, blood bags, and flooring, it is more closely related to real life than any other material and is widely used for purposes where direct contact with the human body is inevitable.
[6]
However, in spite of the compatibility with PVC of phthalate-based plasticizers and excellent softness imparting properties, recently, when PVC products containing phthalate-based plasticizers are used in real life, little by little leakage to the outside of the product causes endocrine disorders (environmental hormones) estimated substances and heavy metal levels. Controversy has arisen that it may act as a carcinogen (NR Janjua et al. "Systemic Uptake of Diethyl Phthalate, Dibutyl Phthalate, and Butyl Paraben Following Whole-body Topical Application and Reproductive and Thyroid Hormone Levels in Humans" Environmental Science and Technology 2008, 42, 7522-7527). In particular, in the 1960s, it was reported that di-(2-ethylhexyl) phthalate (DEHP), the most used phthalate-based plasticizer in the United States, leaked outside PVC products. Global environmental regulations, including various studies on the harmfulness of phthalate-based plasticizers to the human body, began to be implemented.
[7]
Accordingly, many researchers have developed a new non-phthalate-based plasticizer that excludes phthalic anhydride, which is used in manufacturing phthalate-based plasticizers, or suppressed the leakage of phthalate-based plasticizers to respond to environmental hormone problems and environmental regulations caused by the leakage of phthalate-based plasticizers. Research is underway to develop spill control technology that can significantly reduce risks and meet environmental standards.
[8]
On the other hand, as a non-phthalate-based plasticizer, the terephthalate-based plasticizer is not only at the same level in terms of physical properties as the phthalate-based plasticizer, but is also spotlighted as a material free from environmental problems, and various types of terephthalate-based plasticizers are being developed. In addition to research on developing terephthalate-based plasticizers with excellent physical properties, research on facilities for manufacturing such terephthalate-based plasticizers are also being actively carried out. is being requested
[9]
The process of manufacturing such a terephthalate-based plasticizer is also continuously demanded for improvement in various aspects, such as product productivity, separation efficiency of the purification process, product purity, treatment of wastewater due to azeotropic distillation, and energy loss. have.
[10]
[11]
Prior art literature
[12]
(Patent Document 1) Republic of Korea Patent Publication No. 10-2013-0042743
[13]
(Non-Patent Document 1) Mustafizur Rahman and Christopher S. Brazel "The plasticizer market: an assessment of traditional plasticizers and research trends to meet new challenges" Progress in Polymer Science 2004, 29, 1223-1248
[14]
(Non-Patent Document 2) NR Janjua et al. "Systemic Uptake of Diethyl Phthalate, Dibutyl Phthalate, and Butyl Paraben Following Whole-body Topical Application and Reproductive and Thyroid Hormone Levels in Humans" Environmental Science and Technology 2008, 42, 7522-7527
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[15]
The present invention provides a system capable of continuously purifying a crude product mixture generated from an esterification reaction and a continuous purification process using the same, wherein the wastewater of lower alcohol is reduced and the lower alcohol contained in the wastewater can be continuously and efficiently separated. An object of the present invention is to provide a purification system and a purification method for an esterification reaction product.
means of solving the problem
[16]
According to one embodiment of the present invention for solving the above problems, the present invention is an inlet through which the crude product mixture containing an ester and a mixture of two types of alcohols having different carbon numbers is input, and a neutralizing agent to which an aqueous base solution is added as a neutralizing agent a neutralizer including an inlet, an inner space in which neutralization and water separation are performed, a first outlet through which the organic layer fraction is discharged, and a second outlet through which the water layer fraction is discharged; An organic layer fraction inlet connected to the first outlet of the neutralizer, a separation space in which the alcohol mixture is separated, an alcohol-rich stream outlet provided above the separation space, and an ester-rich stream outlet provided below the separation space distiller to do; and a purifier inlet connected to the ester-rich stream outlet of the distiller, a purification space in which gas-liquid separation is performed, an alcohol outlet provided above the purification space to discharge an alcohol fraction, and a lower portion of the purification space to discharge an ester fraction and a product purifier including a product outlet that becomes , wherein the passage starts from the top of the neutralization space.
[17]
According to another embodiment of the present invention, the present invention provides a method for continuous purification of an esterification reaction product that can be implemented through the continuous purification system, and specifically, in a neutralizer having a partition structure, the number of carbon atoms as unreacted Different from each other, the crude product mixture containing the alcohol mixture containing two alcohols selected from those having 3 to 10 carbon atoms and the ester that is the product of the esterification reaction is prepared in an aqueous base solution, in which the ester-rich organic layer fraction and the lower alcohol are layer separation into the contained aqueous fraction (S1); The organic layer fraction is introduced into a distiller, the alcohol-rich stream is removed to the upper part, and the ester-rich stream is discharged to the lower part (S2); and a step (S3) in which the ester-rich stream is fed into the product purifier, the ester fraction is separated at the bottom, and the alcohol fraction is separated at the top (S3).
Effects of the Invention
[18]
According to the present invention, in purifying the product of the esterification reaction, the generation of wastewater containing lower alcohol is reduced, the lower alcohol contained in the wastewater can be efficiently separated, and the process can be continuously performed. and purification methods.
Brief description of the drawing
[19]
1 is a process flow diagram illustrating a continuous purification system equipped with a neutralizer, a still, and a product purifier according to an embodiment of the present invention.
[20]
2 is a process flow diagram illustrating a continuous purification system equipped with a neutralizer, a still, a product purifier, and a filter according to an embodiment of the present invention.
[21]
3 is a process flow diagram illustrating a continuous purification system equipped with a filter, a neutralizer, a still, and a product purifier according to an embodiment of the present invention.
[22]
4 is a process flow diagram illustrating a continuous purification system equipped with a neutralizer, a distiller, a product purifier, a mixed alcohol separation column, and a wastewater treatment tank according to an embodiment of the present invention.
[23]
5 is a graph confirming the amount of alcohol in wastewater in the conventional batch process and the continuous process of the present invention.
Modes for carrying out the invention
[24]
Hereinafter, the present invention will be described in more detail to help the understanding of the present invention.
[25]
The terms or words used in the description and claims of the present invention should not be construed as being limited to their ordinary or dictionary meanings, and the inventor must properly understand the concept of the term in order to best describe his invention. Based on the principle that can be defined, it should be interpreted as meaning and concept consistent with the technical idea of ​​the present invention.
[26]
[27]
The term “crude reaction product” according to the present specification may be a crude reaction product immediately after the reaction is performed in a reactor, and specifically may refer to a reaction product that has not been subjected to an extraction process through steam.
[28]
The term "abundant" according to the present specification means a component that occupies 50% by weight or more of them when there are two components in the fraction, or means a component that occupies the largest amount of these when there are three or more components may be doing
[29]
What is meant by “top” of the equipment described herein, for example, a column, still, neutralizer, or wastewater treatment tank, is, unless specifically stated otherwise, to the side, including the top surface, of each equipment. may include a side upper section positioned upward from the center in the height direction of It may include a lower side cross-section located in the.
[30]
[31]
continuous purification system
[32]
The continuous purification system according to an embodiment of the present invention includes an inlet 12 to which the crude product mixture is introduced, a neutralizer inlet 15 to which an aqueous base solution is input, an internal space 11 where neutralization and water separation are performed, and an organic layer a neutralizer 1 including a first outlet 13 through which the fraction is discharged and a second outlet 14 through which the aqueous layer fraction is discharged; An organic layer fractionation inlet 22 connected to the first outlet 13 of the neutralizer, a separation space 21 in which the alcohol mixture is separated, and an alcohol-rich stream outlet 24 provided above the separation space 21 and a still (2) comprising an ester-rich stream outlet (23) provided at a lower portion of the separation space; and a purifier inlet 32 ​​connected to the ester-rich stream outlet 23 of the still, a purification space 31 in which gas-liquid separation is performed, an alcohol outlet 34 provided above the purification space to discharge an alcohol fraction, and and a product purifier 3 provided at a lower portion of the refining space and including a product outlet 33 through which the ester fraction is discharged.
[33]
In addition, the inner space 11 of the neutralizer has one or more partition walls 113 such that the neutralization space 111 and the layer separation space 112 are divided in the left and right directions to form a passage 114 connecting the two spaces. As provided, the passage 114 starts from the upper portion of the neutralization space 111 .
[34]
Referring to FIG. 1 , in the continuous purification system according to an embodiment of the present invention, an internal space 11 is divided left and right by one or more partition walls 114 , and a neutralization space 111 on the left and layer separation on the right The space 112 is divided into an inlet 12 and a neutralizer inlet 15 provided on the neutralization space 111 side, and a first outlet 13 and a layer separation space provided on the upper side of the layer separation space 112 . (112) In the neutralizer (1), which includes a second outlet (14) provided on the lower side, the crude product mixture is separated into an organic layer and an aqueous layer.
[35]
The organic layer fraction separated in the neutralizer 1 is connected to the still 2 through the first outlet 13 , and specifically is connected to the organic layer fraction inlet 22 of the still 2 . The distiller 2 is provided with a separation space 21 in which alcohol separation such as vacuum extraction and steam extraction is performed inside, and an alcohol-rich stream outlet 24 is provided at the upper part, and an ester-rich stream outlet ( 23) is provided. In the still 2, the content of alcohol in the organic layer fraction is reduced through the extraction of alcohol, and at the same time, it can serve to control the loading amount of the product purifier 3 disposed at the rear end.
[36]
An ester-rich stream is discharged through an ester-rich stream outlet 23 to the lower portion of the still 2 , which is connected to the purifier inlet 32 ​​of the product purifier 3 and is injected into the refining space 31 . In this refining space, gas-liquid separation may be performed as an azeotropic distillation, that is, a distillation process through steam, and as a result, the alcohol contained in the ester-rich stream is discharged to the alcohol outlet 34 provided at the upper part, and the product outlet provided at the lower part Furnace (34) discharges the ester to be commercialized.
[37]
The continuous purification system according to the present invention may further comprise a filter.
[38]
2 and 3, the filter 4 is connected to the product outlet 33 of the product purifier 3, as in FIG. 2, so that filtration can be performed in the filtration space 41, and the final product is It may be discharged through a filtrate discharge line 42 . In addition, the filter 4 may be disposed before the purification process is performed, and as shown in FIG. 3, the filter 4 is disposed at the rear end of the neutralizer 1 so that the organic layer fraction can be filtered first, In this case, the organic layer fraction inlet 22 may be connected to the filter 4 , and the filtrate discharge line 42 may be connected to the still 2 . However, it may be more preferable in terms of quality of the final product that the filter is designed at the rear end of the product purifier as shown in FIG. 2 .
[39]
According to one embodiment of the invention, the system comprises a mixed alcohol supply 52 to which the outlet 24 of the alcohol rich stream of the still 2 and the alcohol outlet 34 of the product purifier 3 are connected; a mixed alcohol separation column 5 including an upper removal unit 55 through which water is discharged, a middle discharge unit 54 through which lower alcohol is discharged, and a lower discharge unit 53 through which higher alcohol is discharged; and a lower alcohol wastewater line 62 connected to the second outlet 14 of the neutralizer 1, a higher alcohol supply line 63 connected to the lower outlet 53 of the mixed alcohol separation column 5, a wastewater treatment tank 6 including a wastewater treatment space 61 where mixing and delamination are performed, an alcohol mixture discharge line 64 through which higher alcohols and lower alcohols are discharged, and a process wastewater treatment line 65; can do.
[40]
The wastewater treatment space 61 of the wastewater treatment tank 6 is provided with one or more partition walls so that the mixing space and the layer separation space are respectively divided in the left and right directions to form a passage connecting the two spaces, the passage It may start from the upper part of the mixing space, and the alcohol mixture discharge line 64 of the wastewater treatment tank may be connected to the mixed alcohol supply part 52 of the mixed alcohol separation column 5 .
[41]
4, the wastewater treatment tank 6 and the mixed alcohol separation column 5 may be further disposed. In the case of the mixed alcohol separation column 5, the alcohol-rich stream outlet ( 24) and the alcohol outlet 34 of the product purifier 3 may be connected to the supply part 52 of the mixed alcohol separation column 5, water to the top removal part 55, and the stop discharge part 54 Lower alcohol may be discharged to the furnace, and higher alcohol may be discharged to the lower discharge unit 53 . Furthermore, separation of water, lower alcohol and higher alcohol is performed in the alcohol separation space 51 , which will be described later.
[42]
In addition, the wastewater treatment tank 6 may be a space in which the aqueous layer fraction discharged to the second outlet 14 of the neutralizer 1 is treated, and the wastewater treatment tank has a second outlet 14 of the neutralizer 1 It may be connected to the lower alcohol wastewater line 62 of the wastewater treatment tank 6 , and the treatment of wastewater may be performed by higher alcohol separated from the mixed alcohol separation column 5 , which is disposed at the bottom discharge unit 53 . It can be supplied through the higher alcohol supply line 63 through. In the wastewater treatment tank, a higher alcohol and a lower alcohol are separated into an organic layer by layer separation, and the mixed alcohol is discharged through an alcohol mixture discharge line 64, which may be connected to the supply unit 52 of the mixed alcohol separation column, Wastewater with substantially no or minimal alcohol may be discharged through process wastewater treatment line 65 or recycled to process water.
[43]
[44]
Continuous purification method
[45]
According to an embodiment of the present invention, in a neutralizer having a barrier rib structure, an ester that is a product of an esterification reaction with an alcohol mixture containing two alcohols having different carbon numbers as unreacted substances and selected from those having 3 to 10 carbon atoms. A step of layer-separating the crude product mixture containing a base into an ester-rich organic layer fraction and a lower alcohol-containing aqueous layer fraction under an aqueous base solution (S1); The organic layer fraction is introduced into a distiller, the alcohol-rich stream is removed to the upper part, and the ester-rich stream is discharged to the lower part (S2); and a step (S3) in which the ester-rich stream is fed into the product purifier, the ester fraction is separated at the bottom, and the alcohol fraction is separated at the top (S3).
[46]
In the conventional purification method, after the reaction is performed, dealcoholization, neutralization/washing and product separation are discontinuously performed in the reactor in a discontinuous manner, or each of the above processes is performed in a discontinuous manner in each device. In the case of a continuous process, it was common to introduce a buffer tank at the front of the column where separation occurs continuously to control the loading amount of the column and to provide continuity. However, in the case of the purification method according to the present invention, it is possible to simultaneously serve as a buffer tank by providing a partition wall in the neutralizer, and neutralization and water separation are performed simultaneously while crossing the partition wall in an overflow manner in the neutralizer. The advantage is that the organic fraction can be continuously fed to the column.
[47]
The continuous purification method according to an embodiment of the present invention may be performed with respect to a crude reaction product containing 50 to 95 parts by weight of an ester and 5 to 50 parts by weight of an alcohol mixture. As defined in the definition of the term, the crude reaction product may be a product included in the stream immediately after leaving the reactor, or may be a product in a state in which alcohol is not separately removed through steam extraction.
[48]
However, it does not exclude filtration by a filter between the reactor and the neutralizer or stream exchange for heat exchange, and does not exclude equipment such as a reboiler, a condenser, or a pump in process design.
[49]
[50]
Reaction raw materials and esterification reaction
[51]
The continuous purification method according to an embodiment of the present invention is a method of purifying a product of an esterification reaction, and the esterification reaction may be a transesterification reaction in which an ester and an alcohol are reacted.
[52]
The ester refers to a compound containing one or more ester groups, and may be, for example, a carboxylate-based compound, a dicarboxylate-based compound, a tricarboxylate-based compound, or a tetracarboxylate-based compound. In addition, the dicarboxylate-based compound may be selected from the group consisting of terephthalate, isophthalate, phthalate, cyclohexane 1,2-diester, cyclohexane 1,3-diester, and cyclohexane 1,4-diester. In the case of a tricarboxylate-based compound, it may be selected from the group consisting of citrate, trimellitate, and cyclohexane tricarboxylate-based compounds, and in the case of a tetracarboxylate-based compound, a benzenetetracarboxylate-based compound, furan tetracarboxylate It may be selected from the group consisting of compound, cyclohexane tetracarboxylate compound, and tetrahydrofuran tetracarboxylate compound.
[53]
The ester may be a mixture composition of two or more ester compounds, and a mixture of two or more ester compounds may mean that two or more of the same or heterogeneous esters are included, but from the viewpoint of purifying one type of esterification reaction product. It may be preferable that two or more esters of the same type are included.
[54]
In addition, the alcohol may be a mixture of two alcohols having different carbon numbers, and may have 3 to 10 carbon atoms. Among these two alcohols, an alcohol having a small carbon number is a lower alcohol, and an alcohol having a large carbon number is a higher alcohol. can be called Preferably, the higher alcohol may have 6 to 10 carbon atoms, and the lower alcohol may have 3 to 5 carbon atoms.
[55]
Here, the lower alcohol may be a reactant of the transesterification reaction or an unreacted product thereof, and the higher alcohol may be a reaction product in which an ester, which is a reactant of the transesterification reaction, is prepared, and may be a reactant of the direct esterification reaction or an unreacted product thereof. In addition, a lower alcohol is used in the direct esterification reaction in which the ester is prepared and a higher alcohol is used in the transesterification reaction, so that the reaction may be performed in the opposite direction to the above case. However, no matter which route the reaction is carried out, the crude product mixture may contain both a lower alcohol and a higher alcohol.
[56]
Specific reaction conditions (temperature, pressure, time, etc.) of the transesterification reaction and the direct esterification reaction may be reaction conditions applied in the art, but are not particularly limited thereto.
[57]
According to an embodiment of the present invention, the reactor in which the transesterification reaction is carried out may in particular be a continuous stirred tank reactor (CSTR) and/or a plug flow reactor (PFR), preferably a plug flow reactor, or a plug The reaction may be carried out in a facility in which a flow reactor and a continuous stirred tank reactor are installed sequentially.
[58]
[59]
Step S1: Neutralization Step
[60]
According to an embodiment of the present invention, in the continuous purification method, in a neutralizer having a barrier rib structure, an alcohol mixture comprising two alcohols selected from those having different carbon numbers and having 3 to 10 carbon atoms as unreacted substances and an esterification reaction A step (S1) in which the crude product mixture containing the product ester is layer-separated into an ester-rich organic layer fraction and an aqueous layer fraction containing a small amount of an alcohol mixture under an aqueous base solution (S1) is primarily performed.
[61]
On the other hand, in the case of the process of purifying the product of the existing esterification reaction, when the reaction is completed, neutralization is performed to preferentially deactivate the catalyst, and after neutralization, alcohol is distilled under reduced pressure in a reactor or distillation apparatus in which the esterification reaction is performed. It is a method for separating unreacted alcohol from an ester product, and it is a method that has been generally performed because it has an advantage in that it has high efficiency. In addition, it is common for water to be removed to the top of the equipment together with the alcohol mixture in that distillation under reduced pressure is performed after neutralization on the structure of the equipment.
[62]
As such, when water is mixed with an alcohol mixture, particularly a lower alcohol, and separated, the lower alcohol is highly soluble in water, so its separation is quite difficult, and it accounts for an amount exceeding about 3.0% by weight in the total stream, There is a problem of being classified as a serious level of wastewater, and its separation and treatment require significant cost and energy. In addition, in an effort to reduce the content of lower alcohol in the wastewater, a dealcoholization process in which unreacted alcohol is distilled under reduced pressure immediately after the reaction is completed is also performed.
[63]
Accordingly, in the continuous manufacturing method according to the present invention, a neutralizer having a barrier rib structure is introduced, and through the introduction of the neutralizer, the water separation process (layer separation) can be performed to a significant degree along with the neutralization process. In the case of neutralization and water separation through the neutralizer according to the present invention, the alcohol mixture can be sent to the organic layer rich in esters, thereby minimizing the alcohol, particularly the lower alcohol, flowing into the water layer.
[64]
That is, in the past, water and alcohol had to be separated in a state in which the ester was not present. However, in the present invention, since the alcohol can be induced into the organic layer by layer separation in the state in which the ester is present, the low grade contained in water It may have the advantage of minimizing alcohol. The water layer separated in this way may contain 0.5 to 3.0 parts by weight of the lower alcohol based on 100 parts by weight of the mixed weight of water and the lower alcohol. Substantially, it may be 2.0 parts by weight or less, and more substantially, it may be 1.0 parts by weight or less, and the content of lower alcohol in wastewater may be reduced compared to the existing process.
[65]
On the other hand, in the continuous purification process according to the present invention, the crude product mixture may include 50 to 95 parts by weight of ester and 5 to 50 parts by weight of alcohol, and since the process of removing unreacted substances is not performed, the product is The alcohol content may be slightly higher than the ester.
[66]
[67]
heavy weapon
[68]
According to an embodiment of the present invention, since the neutralizer has a partition structure, the purification process can be continuously operated. Although the structure of the partition wall structure is not particularly limited, at least one partition wall needs to be installed so that a space is divided into at least two spaces inside the neutralizer and a passage connecting the two spaces can be provided. For example, the neutralizer may have the same structure as described for the continuous purification system.
[69]
In addition, the outlet stream (outlet of the organic layer fraction) through which the organic layer fraction of the neutralizer flows and the inlet stream (inlet) of the neutralizer through which the crude product mixture flows may be mutually heat exchanged. The crude product mixture that has finished the transesterification reaction needs cooling because it is introduced at a high temperature due to the high-temperature reaction, and the organic layer fraction input to the distillation column to be described later requires heating for distillation. Energy consumption can be reduced by utilizing unnecessary heat in the inlet stream as heat required in the outlet stream.
[70]
According to an embodiment of the present invention, the neutralization of the crude reaction product generated by the esterification reaction is performed in the neutralizer, and the neutralizing agent may be an aqueous base solution having a base concentration of 0.1 to 50% by weight, for example, sodium hydroxide Or it may be an aqueous sodium hydrogen carbonate solution. As a neutralizing agent, an aqueous base solution having the same base concentration as described above may be used, but both neutralization of the catalyst and neutralization of the reaction product may be performed. Accordingly, the salt generated from the neutralization can be discharged through the waste liquid treatment port.
[71]
The crude product mixture is introduced into a neutralizer, so that both the catalyst and the reaction product can be neutralized by an aqueous base solution as a neutralizing agent, and can be separated into an organic layer fraction and an aqueous layer fraction, and the organic layer fraction is rich in ester but contains alcohol and may be accompanied by a small amount of alcohol and traces of esters in the aqueous phase fraction.
[72]
Here, the organic layer fraction may include 50 to 95 parts by weight of an ester and 5 to 50 parts by weight of an alcohol mixture, most of the alcohol may be separated in the neutralization and water separation process, and only a portion of the lower alcohol as a part of the alcohol It may be the inflow into this aqueous layer. Meanwhile, since the content of the lower alcohol contained in the aqueous layer has been described above, the description thereof will be omitted.
[73]
In addition, the neutralization space, the layer separation space, and the passage separated by the partition wall of the neutralizer are formed. In the neutralization space, the incoming crude product mixture is neutralized with an aqueous base solution to form a salt, and overflows through the passage into the layer separation space. Layer separation can be induced by continuously moving a certain amount by an overflow method. As the layers are separated in the layer separation space, the liquid level of the organic layer continuously rises so that the organic layer fraction can be discharged from the upper end of the layer separation space, and the aqueous layer fraction containing salt and lower alcohol through the waste liquid treatment port provided at the bottom of the layer separation space This can be emitted.
[74]
Neutralization and water separation performed in the neutralizer may be carried out in the range of about 30 to 150 ℃, the capacity of the neutralizer may be about 5 to 300 m 3 , and other features not mentioned in this specification, such as flow rate Matters applied in the art may be applied without particular limitation.
[75]
[76]
Step S2: Removal of Alcohol
[77]
According to an embodiment of the present invention, in the continuous purification method, the organic layer fraction is put into a still, the alcohol-rich stream is removed to the upper part, and the step (S2) in which the ester-rich stream is discharged to the lower part is performed a second time.
[78]
The continuous purification method according to the present invention is a step of removing the alcohol present in the organic layer fraction by performing the step S2, and in particular, may be a step in which the lower alcohol is mostly removed.
[79]
The distiller may be applied to a column, but vacuum distillation may be applied in a drum type facility, and may be applied without particular limitation as long as it is a facility capable of removing alcohol mainly from lower alcohol. In addition, when a column is installed, a buffer tank may be installed as an additional facility at the front end thereof, but preferably, a facility such as a drum-type flash drum is installed to control the loading amount of the product purifier at the rear end. it could be
[80]
That is, in step S2 according to an embodiment of the present invention, the organic layer fraction may contain esters, lower alcohols and higher alcohols. It can have the advantage of being able to easily separate and control the loading amount of the product purifier at the rear end.
[81]
At this time, the alcohol-rich stream separated to the upper part of the still may contain 50 to 100 parts by weight of lower alcohol and 0 to 50 parts by weight of higher alcohol relative to 100 parts by weight of the total material in the stream, and the ester-rich stream separated into the lower part. may contain 50 to 99 parts by weight of the ester and 1 to 50 parts by weight of the higher alcohol based on 100 parts by weight of the total material in the stream.
[82]
The distiller may have a capacity of about 1 to 300 m 3 , and separation may be performed at about 30 to 200° C., and pressure conditions may be applied from normal pressure to a reduced pressure level of 10 mmHg. This range is a level at which the purification process can be performed normally and efficiently, and when the above range is satisfied, efficient purification can be performed.
[83]
[84]
wastewater treatment tank
[85]
According to an embodiment of the present invention, the aqueous layer fraction separated in the neutralizer may be sent to a wastewater treatment tank to be treated as wastewater. The aqueous phase fraction of the neutralizer is input to the wastewater treatment tank. In this case, the higher alcohol separated in the purification process (separated in a mixed alcohol column below) may be used for wastewater treatment. That is, layer separation may be performed into an alcohol layer containing a higher alcohol and a lower alcohol and a waste water layer through additional input of higher alcohol.
[86]
The wastewater treatment tank may have substantially the same structure as the above-described neutralizer, and may be one in which a higher alcohol is added together with the aqueous layer fraction to perform organic/water separation, and water, higher alcohol and lower alcohol are divided into an organic layer and an aqueous layer. In the case of separation, the alcohol mixture in the organic layer and the lower alcohol in the aqueous layer may be present in an amount of 0.01 to 3.0% by weight or less based on the total weight of the wastewater layer, and may include process wastewater substantially free of lower alcohol.
[87]
Conventionally, after completion of the reaction, neutralization is performed, and then the alcohol mixture with water is separated by distillation, and the separated stream is introduced into the following mixed alcohol separation column and separation is performed. It is extremely low, and there has been a problem that a significant amount of energy is consumed for separation, but there is an advantage that lower alcohol in wastewater can be easily separated without energy consumption by performing layer separation through the wastewater treatment tank according to the present invention.
[88]
[89]
mixed alcohol column
[90]
The continuous purification method according to an embodiment of the present invention may be to perform a transesterification reaction as a reaction containing two or more alcohols, and accordingly, separation and recovery of used or unreacted alcohol is dependent on purification efficiency. can have a significant impact. For example, when both a lower alcohol and a higher alcohol are used in the transesterification reaction, moisture (such as the upper stream of the product purifier) ​​generated in the process is included together with the alcohol to form an azeotrope of three phases. For the separation of these three phases, there are problems such as requiring a significant number of column stages or introducing several distillation column equipment.
[91]
However, in the continuous purification method according to an embodiment of the present invention, a mixed alcohol column is introduced, and a mixed alcohol tank for buffering the alcohol loading is introduced therewith, thereby separating water, a three-phase mixture of a lower alcohol and a higher alcohol. can facilitate
[92]
The alcohol-rich stream separated into the upper part of the above-mentioned distiller, the alcohol fraction separated by the upper part of the above-mentioned product purifier, and the alcohol layer of the wastewater treatment tank may be input to the mixed alcohol column.
[93]
In the mixed alcohol column, water, higher alcohol and lower alcohol may be separated, and water may be removed from the upper part of the column, and in the case of lower alcohol, it is discharged and recovered through an outlet provided on the middle side of the column to be reused in the reaction. and the higher alcohol may be discharged from an outlet located at the bottom of the column. The higher alcohol may also be reused in the process, and a portion thereof may be introduced into the aforementioned wastewater treatment tank to recover the lower alcohol contained in the wastewater, and may be recovered together with the mixed alcohol tank.
[94]
[95]
Step S3: Ester obtaining step in the product refiner
[96]
According to an embodiment of the present invention, in the continuous purification method, the step (S3) in which the ester-rich stream is fed to a product purifier, the ester fraction is separated at the bottom, and the alcohol fraction is separated at the top (S3) is performed for the third time.
[97]
In step S3, the final product may be separated using a product purifier, and in this purifier, the organic layer fraction from which the lower alcohol is removed is separated from the alcohol remaining in the fraction to the upper part, and the ester to be commercialized is separated to the lower part. it could be Distillation using steam may also be performed in this purifier, and the purifier may be in the form of a column or a drum, but may be preferably a column.
[98]
The capacity of the product purifier may be 1 to 300 m 3 , may be performed at 30 to 200° C., and pressure conditions may be applied from normal pressure to a reduced pressure level of 10 mmHg. This range is a level at which the purification process can be performed normally and efficiently, and when the above range is satisfied, efficient purification can be performed.
[99]
The ester fraction separated to the lower part in the product purifier is commercialized, and the alcohol fraction separated to the upper part is transferred to the mixed alcohol tank to perform three-phase separation in the mixed alcohol column.
[100]
[101]
filtration step
[102]
According to an embodiment of the present invention, the continuous purification method may further include filtration through a filter.
[103]
The filtering step may be performed on the crude product mixture before step S1, or on the ester fraction, which is a product separated into the bottom after step S3. That is, the filter may be installed at the front end of the neutralizer, and may be installed at the rear end of the separation column bottom stream, which is the final product column. For filtration, methods known in the art may be applied without particular limitation, and filtration may be performed using filters of various materials.
[104]
[105]
Experimental example
[106]
The alcohol content remaining in the wastewater generated when the conventional batch purification process was used and the wastewater generated when the continuous purification process of the present invention was used was compared. In the case of the conventional batch purification process, the crude product mixture was transferred to a neutralizer of the prior art without a partition wall, and then an appropriate amount of an aqueous base solution was added as a neutralizer and stirred to complete neutralization. After that, the entire amount of the neutralized crude product mixture is transferred to a separate layer separation device to separate the water layer, then transferred to another separate wastewater treatment tank and treated with higher alcohol to collect the wastewater with reduced alcohol content. got it
[107]
The crude product mixtures used in each purification process were identical to each other and contained butanol, and finally, the purification effect in each purification process was compared by comparing the content of butanol remaining in the wastewater obtained from each process. The butanol content in the wastewater was measured using gas chromatography (GC). In addition, it was confirmed how much the butanol content in the wastewater could be reduced by treating the wastewater obtained in each process with various amounts of 2-ethylhexanol. Specifically, an appropriate amount of 2-ethylhexanol was added to 60 g of wastewater, stirred for 30 minutes, left still for 30 minutes, the wastewater layer was separated, and the remaining butanol content was checked by gas chromatography. The butanol content in the wastewater with respect to the input amount of 2-ethylhexanol is graphically shown in FIG. 5 .
[108]
As shown in FIG. 5 , the wastewater obtained in the batch refining process showed a butanol content of 3%, whereas the wastewater obtained in the continuous refining process of the present invention showed a butanol content of 1.4%, which is less than half of the conventional batch refining process. It was confirmed that the alcohol content in the wastewater was indicated. In addition, it was confirmed that the butanol content in the wastewater of the continuous purification process of the present invention was lower than that of the conventional batch purification process in all cases where butanol was removed from the wastewater by additionally treating the wastewater with 2-ethylhexanol.
[109]
[110]
Explanation of symbols
[111]
1: Heavy Weapons 11: Internal Space
[112]
12: inlet 13: first outlet
[113]
14: second outlet 15: neutralizer inlet
[114]
2: still 21: separation space
[115]
22: organic phase fraction inlet 23: ester rich stream outlet
[116]
24: alcohol rich stream outlet
[117]
3: product purifier 31: purification space
[118]
32: purifier inlet 33: product outlet
[119]
34: alcohol outlet
[120]
4: filter 42: filtrate discharge line
[121]
5: mixed alcohol separation column 51: mixed alcohol separation space
[122]
52: mixed alcohol supply part 53: bottom discharge part
[123]
54: middle discharge part 55: top removal part
[124]
6: wastewater treatment tank 61: wastewater treatment space
[125]
62: alcohol wastewater line 63: advanced alcohol supply line
[126]
64: alcohol mixture discharge line 65: process wastewater treatment line
Claims
[Claim 1]
An inlet through which an ester and a crude mixture containing a mixture of two types of alcohols having different carbon numbers is fed, a neutralizing agent inlet through which an aqueous base solution is added as a neutralizing agent, an internal space where neutralization and water separation are performed, and a first through which the organic layer fraction is discharged a neutralizer including an outlet and a second outlet through which the aqueous layer fraction is discharged; An organic layer fraction inlet connected to the first outlet of the neutralizer, a separation space in which the alcohol mixture is separated, an alcohol-rich stream outlet provided above the separation space, and an ester-rich stream outlet provided below the separation space distiller to do; and a purifier inlet connected to the ester-rich stream outlet of the distiller, a purification space in which gas-liquid separation is performed, an alcohol outlet provided above the purification space to discharge an alcohol fraction, and a lower portion of the purification space to discharge an ester fraction and a product purifier including a product outlet that becomes , wherein the passage starts from the top of the neutralization space.
[Claim 2]
The continuous purification system according to claim 1, wherein the neutralizer further comprises a neutralizing agent inlet through which the aqueous base solution is introduced into the neutralization space and a waste liquid treatment port discharged from the layer separation space.
[Claim 3]
The system of claim 1 , wherein the system comprises: a mixed alcohol supply to which the outlet of the alcohol rich stream of the still and the alcohol outlet of the product purifier are connected, a top remover through which water is discharged, a stop outlet through which the lower alcohol is discharged, a high grade a mixed alcohol separation column including a bottom outlet through which alcohol is discharged; and a lower alcohol wastewater line connected to the second outlet of the neutralizer, a higher alcohol supply line connected to the bottom outlet of the mixed alcohol separation column, a wastewater treatment space where mixing and layer separation are performed, higher alcohol and lower alcohol are discharged A wastewater treatment tank comprising an alcohol mixture discharge line and a process wastewater treatment line to be used, and the wastewater treatment space of the wastewater treatment tank is divided into the mixing space and the layer separation space in the left and right directions to connect the two spaces One or more partition walls are provided so as to form a passage, wherein the passage starts from an upper portion of the mixing space.
[Claim 4]
In the neutralizer having a barrier rib structure, the crude product mixture containing an alcohol mixture containing two alcohols having different carbon numbers as unreacted substances and selected from those having 3 to 10 carbon atoms and an ester that is a product of the esterification reaction is a base Layer separation into an ester-rich organic layer fraction and an aqueous layer fraction containing a lower alcohol under an aqueous solution (S1); The organic layer fraction is introduced into a distiller, the alcohol-rich stream is removed to the upper part, and the ester-rich stream is discharged to the lower part (S2); and a step (S3) in which the ester-rich stream is fed into the product purifier, the ester fraction is separated at the bottom, and the alcohol fraction is separated at the top (S3).
[Claim 5]
The continuous purification method according to claim 4, wherein the aqueous layer fraction includes water and a lower alcohol, and the lower alcohol in the aqueous layer fraction is included in an amount of 0.5 to 3.0 parts by weight based on 100 parts by weight of a mixed weight of water and lower alcohol.
[Claim 6]
5. The continuous purification process according to claim 4, wherein both neutralization of the catalyst and neutralization of the crude product mixture are performed in the neutralizer.
[Claim 7]
5. The continuous purification process according to claim 4, wherein the outlet stream through which the organic layer fraction of the neutralizer flows and the inlet stream of the neutralizer through which the crude product mixture flows are subjected to mutual heat exchange.
[Claim 8]
[Claim 5] The continuous purification method according to claim 4, wherein the concentration of the base in the aqueous base solution fed into the neutralizer is 0.1 to 50 wt%.
[Claim 9]
The continuous purification method according to claim 4, wherein the separation is performed by distillation using steam in the product purifier of step S3.
[Claim 10]
5. The method of claim 4, wherein the purification method further comprises the step of filtering through a filter, wherein the filtering step is performed on the crude product mixture before step S1, or separated into the bottom after step S3. A continuous purification method carried out on the ester fraction, which is the product.
[Claim 11]
The continuous purification method according to claim 4, wherein the aqueous layer fraction is introduced into a wastewater treatment tank, and is separated into an alcohol layer containing a higher alcohol and a lower alcohol and a wastewater layer through additional input of higher alcohol.
[Claim 12]
The method according to claim 11, wherein the alcohol-rich stream separated at the top of the distiller, the alcohol fraction separated at the top of the product purifier, and the alcohol layer of the wastewater treatment tank are fed into a mixed alcohol separation column to separate higher alcohols and lower alcohols. A continuous purification method that is
[Claim 13]
The continuous purification method according to claim 11, wherein the lower alcohol content in the wastewater layer is 3.0 wt% or less based on the total weight of the wastewater layer.
[Claim 14]
5. The method of claim 4, wherein the ester is terephthalate, isophthalate, phthalate, cyclohexane 1,2-diester, cyclohexane 1,3-diester, cyclohexane 1,4-diester, citrate, trimellitate , cyclohexane tricarboxylate-based compound, benzenetetracarboxylate-based compound, furan tetracarboxylate-based compound, cyclohexane tetracarboxylate-based compound, and tetrahydrofuran tetracarboxylate-based compound is at least one selected from the group consisting of continuous purification method.