阅读说明：本技术 二酯类材料生产单元和包括其的二酯类材料生产系统 (Diester material production unit and diester material production system comprising same ) 是由 郑在勋 李成圭 秋渊旭 田炯 金显圭 陈赞携 朴振成 于 2020-07-02 设计创作，主要内容包括：本发明涉及一种二酯类材料生产单元,包括：反应装置,在反应装置中进行二羧酸与伯醇的酯化反应；塔,在塔中进行引入的伯醇和水的气液分离；热交换器,安装在塔的气相管线上以移除气相管线的热量；闪蒸罐,在闪蒸罐中在包含伯醇和水的混合物流中进行液相和气相的分离；冷凝器,安装在闪蒸罐上部管线上；以及层分离器,在层分离器中进行液化的伯醇和水的混合物向有机层和水层的层分离,其中,来自闪蒸罐和层分离器的再循环的伯醇流经的管线中的一个或多个管线连接到塔的上部。根据本发明,可以减少冷却剂使用量并且可以消除由于液相和气相共存于管道中导致的流变问题。(The invention relates to a diester material production unit, which comprises: a reaction device, in which esterification reaction of dicarboxylic acid and primary alcohol is carried out; a column in which gas-liquid separation of the introduced primary alcohol and water is performed; a heat exchanger installed on a gas phase line of the tower to remove heat of the gas phase line; a flash tank in which a separation of liquid and gas phases is performed in a mixture stream comprising primary alcohol and water; the condenser is arranged on the upper pipeline of the flash tank; and a layer separator in which layer separation of the liquefied mixture of primary alcohol and water into an organic layer and an aqueous layer is performed, wherein one or more of the lines through which the recycled primary alcohol from the flash tank and the layer separator flows are connected to an upper portion of the column. According to the present invention, the amount of coolant used can be reduced and the rheological problems caused by the coexistence of liquid and gas phases in the piping can be eliminated.)

1. A diester-based material production unit comprising:

a reaction apparatus comprising a reaction vessel in which an esterification reaction of a dicarboxylic acid and a primary alcohol is carried out, and a gas phase discharge line installed at an upper end of the reaction vessel such that vaporized primary alcohol and water are discharged to a column through the gas phase discharge line;

the column comprising a column body in which gas-liquid separation of primary alcohol and water introduced from the gas-phase discharge line is performed, a liquid-phase line installed at a lower portion of the column body such that a liquefied alcohol-rich stream flows into the reaction device, and a gas-phase line installed at an upper portion of the column body and connected to a side of the flash drum such that a mixed stream of primary alcohol and water in a gas phase flows out;

a heat exchanger installed on the gas phase line of the column and removing heat of the gas phase line;

the flash tank having a flash tank body in which separation of a liquid phase and a gaseous phase in a mixture stream comprising primary alcohol and water is performed, a flash tank lower line from which liquid comprising liquefied primary alcohol is discharged, and a flash tank upper line mounted to discharge the mixture stream of primary alcohol and water in the gaseous phase to a layer separator;

a condenser installed on the flash tank upper line to liquefy the mixture of primary alcohol and water in the gas phase in the flash tank upper line; and

the layer separator, which comprises a separation tank in which a mixture of liquefied primary alcohol and water is separated into a layer separation of an organic layer and an aqueous layer, an organic layer line through which the separated organic layer is discharged, and an aqueous layer line through which the separated aqueous layer is discharged, wherein:

the flash tank lower line is connected to one or more positions selected from the group consisting of a column body side upper part, a column body side lower part, and the reaction vessel,

the organic layer line is connected to one or more positions selected from the group consisting of a flash tank main body side portion, the upper column body side portion, the lower column body side portion and the reaction vessel, and

one or more of the flash tank lower line and the organic layer line are connected to the column body side upper portion.

2. The diester-based material production unit of claim 1, wherein the flash tank lower line is connected to the column body side upper portion.

3. The diester-based material production unit of claim 1, wherein the organic layer line is connected to the flash tank body side or to the column body side upper portion.

4. The diester-based material production unit according to claim 1, wherein the flash tank lower line is connected to the flash tank body side upper portion, and the organic layer line is connected to the flash tank body side portion.

5. The diester-based material production unit of claim 1, wherein the dicarboxylic acid comprises one or more selected from the group consisting of terephthalic acid, phthalic acid, isophthalic acid, and cyclohexane dicarboxylic acid.

6. The diester-based material producing unit of claim 1, wherein the primary alcohol has from 3 to 10 carbon atoms.

7. The diester-based material production unit of claim 1, wherein the esterification reaction is carried out at a temperature of 150 ℃ to 230 ℃.

8. The diester-based material production unit of claim 1, wherein the temperature of the stream in the gas phase line of the column is from 130 ℃ to 180 ℃.

9. A diester-based material production system comprising:

a reaction section in which two or more diester-based material production units according to claim 1 are connected in series; and

a purification unit that purifies the reaction product discharged from the reaction part.

10. The diester-based material production system according to claim 9, wherein in the reaction portion, 3 to 6 diester-based material production units are connected in series.

Technical Field

Cross Reference to Related Applications

This application claims the benefit of korean patent application No.10-2019-0080461, filed on 7/4.2019 with the korean intellectual property office, the entire disclosure of which is incorporated herein by reference.

Technical Field

The present invention relates to a diester-based material production unit having an improved reflow system and a diester-based material production system including the same.

Background

By the 20 th century, phthalate-based plasticizers have occupied 92% of the world plasticizer market (mustaffier-Rahman and cristoff s. brazel), "plasticizer market: evaluation of conventional plasticizers and research trend to meet new challenges", polymer science development, 2004, 29, 1223-. Phthalate plasticizers are incorporated into PVC at various levels, and since phthalate plasticizers are soft and stretchable, they are used not only for hard products (e.g., rigid pipes) but also for soft products (e.g., food packaging materials, blood bags, and flooring materials). Therefore, the phthalate ester plasticizer is more closely related to real life than any other material, and is widely used for materials in direct contact with the human body.

However, although phthalate plasticizers have compatibility with PVC and excellent softness imparting characteristics, the following controversy exists regarding the harmful properties of phthalate plasticizers: when PVC products containing phthalate plasticizers are used in real life, the phthalate plasticizers may gradually leak out of the product and act as suspected endocrine disrupters (environmental hormones) and carcinogens to heavy metal levels (NR Janjua et al, "systemic absorption of diethyl phthalate, dibutyl phthalate and butyl paraben after systemic topical application and human reproductive and thyroid hormone levels", environmental science and technology, 2008, 42, 7522-d 7527). In particular, since the us published in the 60 th of the 20 th century reported that di-isooctyl phthalate (di (2-ethylhexyl) phthalate, DEHP), the most commonly used phthalate plasticizer, leaked from PVC products, interest in environmental hormones was increasing in the 90 th of the 20 th century, and global environmental regulations have begun to be implemented, in addition to various studies on the harmful properties of phthalate plasticizers on human bodies.

Therefore, in order to cope with environmental hormone problems and environmental regulations due to leakage of phthalate-based plasticizers, particularly di (2-ethylhexyl) phthalate, many researchers have conducted studies to develop a novel non-phthalate-based substitute plasticizer which does not contain phthalic anhydride used in the production of di (2-ethylhexyl) phthalate, and to develop a phthalate-based plasticizer which can substitute for di (2-ethylhexyl) phthalate and can be used for industrial use since leakage of the plasticizer can be suppressed even based on phthalate, and to develop a leakage suppression technology which suppresses leakage of phthalate-based plasticizers, thereby remarkably reducing harm to human bodies and meeting environmental standards.

As described above, regarding the diester-based plasticizer, development of a material which is free from environmental problems and can replace di (2-ethylhexyl) phthalate, which has environmental problems, is actively proceeding. In addition, research into developing diester plasticizers having excellent physical properties and research into apparatuses for manufacturing plasticizers have been actively conducted, and more efficient, economical and simple process design is required in terms of process design.

On the other hand, a batch process is applied in most industrial sites as a process for producing the above-mentioned diester-based plasticizer. Regarding the batch process, an invention related to a gas-liquid separation system for refluxing non-reactants and effectively removing side-reactants in a reactor (Korean patent laid-open No. 10-2019-. However, with respect to the batch process, such an invention is limited in that improvement of the amount of reflux or the amount of steam has a limitation, productivity is very low, and a technique applicable to the improvement has a limitation.

In addition, as a continuous process, an invention (korean patent laid-open No.10-1663586) relating to a process of configuring a reaction part by connecting two or more reactors in series has also been introduced. However, there is a limitation in improving the overall processability only by controlling the reaction temperature of the continuously connected reactors.

[ Prior art documents ]

[ patent document ]

(patent document 1) Korean patent laid-open publication No.10-2019-0027622

(patent document 2) Korean patent laid-open publication No.10-2019-0027623

(patent document 3) Korean patent laid-open publication No.10-1663586

Disclosure of Invention

Technical problem

An aspect of the present invention provides a diester-based material production unit and a diester-based material production system including the same, in which a reflux system is applied to the diester-based material production unit, the diester-based material production unit is applied to a process for continuously producing a diester-based material, the reflux system includes a flash tank and is improved by selecting a suitable location of a stream to be refluxed, thereby solving a rheological problem that may occur due to coexistence of liquid and gas in a pipe or a condenser, the amount of coolant used can be greatly reduced even when the amount of reflux is large, and an alcohol to be refluxed can have a temperature maintained higher than usual and supplied.

Technical scheme

According to an aspect of the present invention, there is provided a diester-based material production unit including: a reaction apparatus comprising a reaction vessel in which an esterification reaction of a dicarboxylic acid and a primary alcohol is performed, and a gas phase discharge line installed at an upper end of the reaction vessel such that vaporized primary alcohol and water are discharged to a column through the gas phase discharge line; the column including a column body in which gas-liquid separation of primary alcohol and water introduced from a gas-phase discharge line is performed, a liquid-phase line installed at a lower portion of the column body such that a liquefied alcohol-rich stream flows into the reaction device, and a gas-phase line installed at an upper portion of the column body and connected to a side of the flash tank such that a mixed stream of primary alcohol and water in a gas phase flows out; a heat exchanger installed on a gas phase line of the tower to remove heat of the gas phase line; a flash tank having a flash tank body in which a separation of liquid and gas phases is performed in a mixture stream comprising primary alcohol and water, a flash tank lower line from which a liquid phase comprising liquefied primary alcohol is discharged, and a flash tank upper line installed to discharge the mixture stream of primary alcohol and water in gas phase to a layer separator; a condenser installed on an upper line of the flash tank to liquefy a mixture of gas-phase primary alcohol and water in the line; and the layer separator including a separation tank in which layer separation of the liquefied mixture of primary alcohol and water into an organic layer and an aqueous layer is performed, an organic layer line through which the separated organic layer is discharged, and an aqueous layer line through which the separated aqueous layer is discharged.

The flash tank lower line of the flash tank of the diester-based material production unit is connected to one or more positions selected from the group consisting of the column body side upper portion, the column body side lower portion, and the reaction vessel.

The organic layer line of the layer separator of the diester-based material production unit is connected to one or more positions selected from the group consisting of a flash tank main body side portion, a column main body side upper portion, a column main body side lower portion, and a reaction vessel.

One or more of the flash tank lower line and the organic layer line of the diester-based material production unit are connected to the upper portion on the column body side.

Advantageous effects

The present invention employs an improved reflux system, and thus, it is possible to solve the rheological problems that may occur due to the coexistence of liquid and gas in the piping and the condenser, to greatly reduce the amount of coolant used even when the amount of reflux is large, and to reduce the amount of vapor in the reactor by maintaining the temperature of alcohol to be refluxed higher than usual.

Drawings

Fig. 1 is a process diagram showing a production unit of a diester-based material according to an embodiment of the present invention.

Fig. 2 is a process diagram showing one example of selected positions of the flash tank lower line and the organic layer line of the diester-based material production unit according to the embodiment of the present invention.

Fig. 3 is a process diagram illustrating one example of selected locations of the flash tank lower line and the organic layer line of the diester-based material production unit according to an embodiment of the present invention.

Fig. 4 is a process diagram showing one example of selected positions of the flash tank lower line and the organic layer line of the diester-based material production unit according to the embodiment of the present invention.

Fig. 5 is a process diagram illustrating one example of selected locations of the flash tank lower line and the organic layer line of the diester-based material production unit according to an embodiment of the present invention.

Fig. 6 is a process diagram illustrating one example of selected locations of the flash tank lower line and the organic layer line of the diester-based material production unit according to an embodiment of the present invention.

Fig. 7 is a process diagram showing one example of selected positions of the flash tank lower line and the organic layer line of the diester-based material production unit according to the embodiment of the present invention.

Detailed Description

Hereinafter, the present invention will be described in more detail to facilitate understanding of the present invention.

It will be understood that the words or terms used in the specification and claims of this invention should not be construed as limited to having the meanings defined in commonly used dictionaries. It will be further understood that the words or terms should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the technical idea of the present invention, based on the principle that the inventor can appropriately define the meaning of the words or terms to best explain the principles of the present invention.

The diester-based material production unit according to an embodiment of the present invention includes: a reaction apparatus comprising a reaction vessel in which an esterification reaction of a dicarboxylic acid and a primary alcohol is carried out, and a gas phase discharge line installed at an upper end of the reaction vessel such that vaporized primary alcohol and water are discharged to a column through the gas phase discharge line; a column including a column body in which gas-liquid separation of primary alcohol and water introduced from a gas-phase discharge line is performed, a liquid-phase line installed at a lower portion of the column body such that a liquefied alcohol-rich stream flows into the reaction device, and a gas-phase line installed at an upper portion of the column body and connected to a side of the flash drum such that a mixed stream of primary alcohol and water in a gas phase flows out; a heat exchanger installed on a gas phase line of the tower to remove heat of the gas phase line; a flash tank having a flash tank body in which a separation of a liquid phase and a gaseous phase is performed in a mixture stream comprising primary alcohol and water, a lower flash tank line from which a liquid phase comprising liquefied primary alcohol is discharged, and an upper flash tank line mounted to discharge the mixture stream of gaseous primary alcohol and water to a layer separator; a condenser installed on an upper line of the flash tank to liquefy a mixture of gas-phase primary alcohol and water in the line; and a layer separator including a separation tank in which a mixture of liquefied primary alcohol and water is separated into an organic layer and an aqueous layer, an organic layer line through which the separated organic layer is discharged, and an aqueous layer line through which the separated aqueous layer is discharged.

Further, the flash tank lower line of the flash tank is connected to one or more positions selected from the group consisting of the column body side upper part, the column body side lower part and the reaction vessel, the organic layer line of the layer separator of the diester-based material production unit is connected to one or more positions selected from the group consisting of the flash tank body side part, the column body side upper part, the column body side lower part and the reaction vessel, and one or more of the flash tank lower line and the organic layer line are connected to the column body side upper part.

When a system for returning a gas-phase material such as an alcohol to be refluxed to the upper portion of a reactor to the reactor is applied in a typical production process of a diester-series material, a system for recovering heat by installing a heat exchanger in the upper portion of a column and returning the recovered heat to the reactor by further liquefaction and layer separation after liquefaction is generally applied.

In this case, in the process of recovering heat from the gas-phase material in the upper part of the column using the heat exchanger, a part of the gas phase is liquefied in the pipeline, and the other part of the gas phase remains as the gas phase, and therefore, the liquid phase and the gas phase coexist in the pipeline, causing a problem of fluid flow, and a problem of a great decrease in the efficiency of the condenser due to the presence of the liquid phase having a relatively slow heat transfer in the pipeline.

Therefore, in the production unit according to the embodiment of the present invention, the liquid phase generated in the line after the heat exchange is not immediately introduced into the layer separator, but is again subjected to the gas-liquid separation by the flash tank, thereby being capable of solving the rheological problem of the fluid flow in the line with the decrease in the efficiency of the condenser. In addition, before performing layer separation after liquefaction and cooling by the condenser, some of the non-reactant can be refluxed to the column and/or the reaction device from the flash tank, and thus, the refluxed non-reactant (for example, alcohol) can be injected again into the reactor while the temperature thereof is maintained at a high temperature, thereby enabling a reduction in the amount of steam used in the reactor when the amount of reflux is the same.

Hereinafter, a diester-based material production unit according to an embodiment of the present invention will be described with reference to the drawings.

Fig. 1 is a process diagram illustrating a production unit 10 of a diester-based material according to an embodiment of the present invention. The equipment for producing the diester material comprises: a reaction apparatus 11 for performing an esterification reaction of a dicarboxylic acid and a primary alcohol in the reaction apparatus 11; a column 12 in which the gas-liquid separation is carried out by extracting alcohol, which is a non-reactant vaporized during the reaction, and water, which is a side reactant, from the water in the column 12; a heat exchanger 16 for recovering heat discharged to a gas phase line 121 of an upper portion of the column; a flash tank 13 for performing gas-liquid separation of the liquefied primary alcohol and the mixture of the primary alcohol and water in a gas phase on the line, so that a liquid phase present in the line is returned to the reaction apparatus before layer separation; a condenser 15 for liquefying the mixture of primary alcohol and water in a gas phase collectively before introducing the mixture into the layer separator; and a layer separator 14, the layer separator 14 for separating a mixture of liquefied primary alcohol and water by layer separation.

Specifically, the production unit 10 includes a reaction device 11, and the reaction device 11 includes: a reaction vessel 110 in which an esterification reaction of a dicarboxylic acid and a primary alcohol is performed; and a gas phase discharge line 111 installed at the upper end of the reaction vessel 110, and the vaporized primary alcohol and water are discharged to the column through the gas phase discharge line 111.

The reaction apparatus 11 may further have: a raw material injection line 112' through which dicarboxylic acid and primary alcohol as raw materials are injected; and a product line 112 for sending the product to the reaction apparatus of the next production unit if a plurality of production units are provided, or to the purification unit when there is a single production unit or when it is the last production unit among the plurality of production units.

However, the raw material injection line 112' may have a further premixer (not shown) installed at the front end of the initial production unit to inject the raw material into the premixer to supply the raw material to the reaction device, or the raw material can be supplied by line-mixing with one raw material input line. Alternatively, the raw materials may be supplied through different injection lines for each raw material. The method of injecting the raw materials is not particularly limited as long as it is a method capable of supplying the raw materials into the reaction apparatus.

In addition, the production unit 10 includes a column 12, and the column 12 connected to the reaction device 11 through the gas-phase discharge line 111 includes: a column body 120 in which gas-liquid separation of the primary alcohol and water introduced from the gas-phase discharge line 111 is performed; a liquid phase line 122 installed at a lower portion of the column body 120 such that the liquefied alcohol-rich stream flows into the reaction device; and a gas phase line 121 installed at an upper portion of the column body 120 and connected to a side of the flash drum 13 such that a mixture stream of the primary alcohol and water of the gas phase flows out.

In the reaction apparatus 11, an esterification reaction is performed in the reaction vessel 110, which may be performed at a temperature of about 150 to 230 ℃ by using dicarboxylic acid and primary alcohol as raw materials. The dicarboxylic acid as a raw material may include one or more selected from the group consisting of terephthalic acid, phthalic acid, isophthalic acid, and cyclohexanedicarboxylic acid, and the primary alcohol as another raw material may have 3 to 10 carbon atoms.

When the esterification reaction is carried out using the raw material, the reaction temperature of the esterification reaction may be higher than the boiling point of the primary alcohol having 3 to 10 carbon atoms used as the raw material, so that vaporization of the primary alcohol inevitably occurs during the reaction. In addition, there arises a problem that the reactants are continuously reduced in the reaction vessel due to vaporization of the primary alcohol. Thus, the reaction is carried out by injecting an excess of primary alcohol above the theoretical equivalence ratio.

Accordingly, the molar ratio of the dicarboxylic acid to the primary alcohol in the reaction part (particularly, the first reaction part in the production system described later) may be 1:2 to 1:5, energy loss due to unnecessary reflux caused by injection of an excessive amount of alcohol may be prevented, and it may be determined in consideration of the excessive amount of alcohol required in achieving the conversion rate of the reaction and controlling the minimum residence time. The molar ratio may preferably be 1:2 to 1:4, and in order to optimally reflect the above, a molar ratio of 1:2.5 to 1:4 may be applied.

In addition, the esterification reaction produces water as a side reactant, but, on the contrary, the production of water may accelerate the reverse reaction and become a cause of preventing achievement of the target conversion rate, and therefore, it is also important to remove water from the reaction vessel.

That is, gas phase water generated during the reaction should be removed in the reaction apparatus 11, and inevitably, an operation of re-liquefying the vaporized primary alcohol and returning the re-liquefied primary alcohol to the reactor is necessary. Therefore, a column 12 is installed in the upper part of the reaction apparatus 11.

In the column 12, gas-liquid separation of the vaporized primary alcohol and water is performed. The mixture of the gas-phase primary alcohol and water is introduced into the lower portion of the column body 120 of the column 12 from the gas-phase discharge line 111 at the upper portion of the reaction vessel 110, and the introduced gas-phase mixture ascends in the column body 120 of the column 12 and contacts the liquid-phase primary alcohol descending from the upper side of the column 12, whereby the primary alcohol and water are separated into the lower portion of the column body 120 and the upper portion of the column body 120, respectively. Here, the liquid-phase primary alcohol descending from the upper portion of the column 12 may be supplied from the flash drum 13 at the rear end or from the layer separator 14.

The primary alcohol and water vaporized in the reaction device 11 are mainly separated by gas-liquid separation in the column 12, and the liquefied primary alcohol is supplied back to the reactor 110 through the liquid phase line 122, and thus, can participate in the reaction. Further, a mixed gas of water and unseparated primary alcohol, which is still in a gas phase, is discharged through a gas phase line 121 at the upper part of the column. At this time, the temperature of the inner gas-phase mixture stream discharged through the gas-phase line 121 may be about 130 ℃ to 180 ℃. Although a portion of the primary alcohol is liquefied and returned to the reactor, the primary alcohol may be in excess, and thus, the weight ratio of primary alcohol to water may be about 1 or greater.

The production unit 10 includes a heat exchanger 16, the heat exchanger 16 is used to recover heat of the gas phase line 121 of the column and transfer it to another place where heat supply is required in the process, and the heat exchanger 16 is installed on the gas phase line 121 of the column 12. The mixed stream of vapor water and primary alcohol withdrawn from the column through the vapor line 121 should be finally liquefied so that the primary alcohol is refluxed and water is removed, which is a stream from which heat should be removed. However, when heat is removed only by the condenser, energy loss is large. Therefore, it is preferable to perform an operation of transferring heat of the mixture flow in the gas phase line to another place in the process through the heat exchanger 16 and removing the heat.

Meanwhile, when heat is removed from the flow in the gas phase line 121 as described above, liquefaction may occur, and in this case, a phenomenon in which liquid and gas coexist in the line may occur. However, when gas and liquid coexist in a pipe, a rheological problem may occur therein, and there are also problems as follows: the cooling efficiency is greatly reduced due to the presence of the liquid phase when the residual heat is subsequently removed by the condenser.

Therefore, in the present invention, the flash tank 13 is introduced to solve the above-mentioned problems. Since the primary alcohol liquefied by the heat exchanger 16 can be recycled through the flash tank 13 immediately before passing through the condenser 15, there is no problem of rheology in piping or a decrease in efficiency of the condenser.

The flash tank 13 connected to the column 12 through the gas phase line 121 has: a flash tank body 130 in which a mixture stream including the partially liquefied primary alcohol and water is subjected to gas-liquid separation; a flash tank lower line 132 through which a liquid phase comprising liquefied primary alcohol is discharged; and a flash tank upper line 131, the flash tank upper line 131 being installed to discharge a mixture stream of gas-phase primary alcohol and water to the layer separator 14.

The flash tank 13 can perform gas-liquid separation inside the flash tank main body 130, and a large amount of primary alcohol can be returned to the reactor by simple equipment and processing. At this time, the liquefied primary alcohol may be recovered to the reaction system through the reaction device 11 or the column 12 via the flash tank lower line 132. Since the temperature of the primary alcohol recovered from the flash tank 13 is higher than that by condensation and cooling, even if the primary alcohol is recovered into the reactor, the temperature variation in the reaction system can be minimized. In addition, since a part of the primary alcohol is mainly separated, the amount of cooling water used in the condenser can be greatly reduced, and thus, the energy saving effect obtained by introducing the flash tank 13 can be significant.

In addition, the production unit 10 includes a layer separator 14. The layer separator 14 connected to the flash tank 13 through the flash tank upper line 131 comprises: a separation tank 140 in which the gas phase discharged from the upper portion of the flash tank is liquefied to perform layer separation into an organic layer and an aqueous layer; an organic layer line 141 through which the separated organic layer is discharged; and a water layer line 142, and a separated water layer is discharged from the water layer line 142.

Further, the production unit 10 includes a condenser 15, the condenser 15 being used for cooling and condensing such that the flow through the flash tank upper line 131 of the flash tank 13 is liquefied before being introduced into the layer separator 14, and the condenser 15 being installed on the flash tank upper line 131. The liquefied liquid phase primary alcohol and water are separated in the separation tank 140 of the layer separator 14 into an organic layer of primary alcohol and an aqueous layer of water.

The primary alcohol in the organic layer may be recycled to the flash tank 13, the column 12, or the reaction apparatus 11 through the organic layer line 141, and the temperature of the primary alcohol stream in the organic layer line may be about 40 ℃ to about 95 ℃. Generally, the reflux is achieved only through the layer separator 14 without primary alcohol recycle through the flash tank 13, so that when the recycled primary alcohol is introduced into the reaction system, the reaction temperature is lowered, and thus, additional steam needs to be supplied to the reactor. However, in the present invention, since the temperature of the primary alcohol recycled from the flash tank 13 is relatively high, an effect of energy saving can be additionally expected.

In addition, water in the water layer is discharged from the separation tank 14 through a water layer line 142. At this time, the discharged water may be used to generate steam as the generated water in the process by an additional separation device, and there is no particular limitation in the use of the water after it is removed from the reaction apparatus.

The production unit 10 according to an embodiment of the present invention includes the flash tank lower line 132 of the flash tank 13 and the organic layer line 141 of the layer separator 14 as lines for refluxing, i.e., recycling, the primary alcohol. When returning the primary alcohol to the reaction apparatus 11, a recycle line may be connected at various positions. The flash tank lower line 132 is connected to one or more positions selected from the group consisting of a side upper portion of the flash tank main body 120, a side lower portion of the column main body 120, and the reaction vessel 110, and the organic layer line 141 is connected to one or more positions selected from the group consisting of a side portion of the flash tank main body 130, a side upper portion of the column main body 120, a side lower portion of the column main body 120, and the reaction vessel 110.

At this time, either one of the flash tank lower line 132 and the organic layer line 141 must be connected to the side upper portion of the column body 120 of the column 12. This is because the gas-liquid separation can be performed only when the gas phase rises in the lower portion of the column body 120 of the column 12 and the liquid phase falls in the upper portion of the column body 120 of the column 12.

Fig. 2 to 7 show an example in which the lines are connected such that the flash tank lower line 132 and the organic layer line 141 are finally introduced into the reaction apparatus 11.

Fig. 2 shows that the flash tank lower line 132 is connected to the side upper portion of the column body 120 of the column 12, and the organic layer line 141 is connected to the side portion of the flash tank body 130 of the flash tank 13. Fig. 3 shows that while the connections of the flash tank lower line 132 are the same, the organic layer line 141 is configured to be connected to the flash tank lower line 132 instead of the side of the flash tank body such that the primary alcohol is recycled through the line connection. Fig. 4 also shows that the connection of the flash tank lower line 132 is the same and that the organic layer line 141 is connected to the side lower part of the column body 120 of the column 12.

In addition, fig. 5 shows that the connection to the side upper portion of the column body 120 of the column 12 is made through the organic layer line 141 of the layer separator 14 and the flash tank lower line 132 is connected to the side lower portion of the column body 120. Fig. 6 shows an example in which the flash tank lower line 132 and the organic layer line 141 are connected to the upper side of the reaction vessel 110 and the column body 120, respectively, and shows an example in which the flash tank lower line 132 and the organic layer line 141 are connected to the upper side of the column body 120 and the reaction vessel 110, respectively.

As described above, in fig. 2 to 7, it can be confirmed that any one of the flash tank lower line 132 and the organic layer line 141 must be connected to the side upper portion of the column body 120 of the column 12. As described above, only one line needs to be connected to the upper side portion of the column body 120 of the column 12. However, it may be appropriately configured in consideration of the fact that the flow temperature of the organic layer line 141 of the layer separator 14 is low, so that the effect is not great in the amount of steam supplied from the reaction device 11 to the reaction vessel, and when introduced into the side lower portion of the column main body 120, it may be difficult to expect an improvement in the gas-liquid separation efficiency in the column 12.

As shown in fig. 2 to 4, it is preferable to connect the flash tank lower line 132 and the organic layer line 141.

According to an embodiment of the present invention, there is provided a reaction section in which two or more of the above-described diester-based material production units are connected in series, and a purification unit for purifying a reaction product discharged from the reaction section.

From the whole process, the above-mentioned production unit of the diester-based material may be one reactor constituting a part of the "reaction section". In the present invention, in a continuous process for producing diester materials, preferably, two or more, preferably 3 to 6 or 3 to 5 production units are connected.

When more than two production units 10 are connected, the product produced in the reaction apparatus 11 can be discharged through the product line 112 and moved to the next production unit. "…" shown in fig. 1-8 may be interpreted as a representation that more than two production units may be coupled.

In particular, a continuous process for producing diester materials may comprise: a first production system including a first reaction section that performs a direct esterification reaction and a first purification unit that purifies a product of the first reaction section; and a second production system including a second reaction part for performing a trans-esterification reaction with the produced diester by additionally injecting an alcohol and a second purification unit for purifying a product of the second reaction part. Further, a wastewater treatment unit or a mixed alcohol separation unit may be included.

The production unit according to an embodiment of the present invention may specifically relate to a first reaction section in a first production system in which a direct esterification reaction is performed. However, even if the first purification unit, the second reaction unit, and the second purification unit at the rear end are not connected together, the reaction process is not particularly limited as long as the reaction process is a process that includes alcohol as a reactant and produces water as a by-product, thereby reducing the amount of steam and the amount of reflux in the reactor.

Examples of the invention

Hereinafter, the present invention will be described in detail with reference to examples. However, the following examples are merely illustrative of the present invention and are not intended to limit the scope of the present invention.

In the following examples and comparative examples, the process according to the CONTINUOUS production of diester-type materials, the process system according to the process of the present invention, was simulated in a commercial process simulation program ASPEN PLUS using a continuos model.

Experimental example 1

In performing the simulation using the above procedure, the simulation was performed by the process shown in fig. 2 in which four identical production units were coupled as raw materials, the dicarboxylic acid was terephthalic acid, the primary alcohol was 2-ethylhexanol, and the molar ratio of the two raw materials was set to 1: 3. The temperature of the organic layer containing the primary alcohol discharged through the organic layer line 141 was set to 40 c, and the connection position of the flash tank lower line 132 and the organic layer line 141 was changed as shown in table 1 below. The amount of the coolant consumed in the condenser 15 and the total flow rate of the steam flowing in the gas phase line 121 of the column 12 were determined, and the values in the following table 1 are relative% assuming that the comparative examples 1-1 are 100%.

[ Table 1]

Referring to table 1 above, it can be confirmed that, since the flash tank is installed, the flow rate of the gas phase line of the column, i.e., the upper portion, is increased, which means that the capacity of the column can be separated from the flash tank. It can be seen that by recirculating the liquid phase once in the flash tank before flowing to the condenser, the cooling efficiency can be greatly improved.

In addition, in the case of examples 1-1 to 1-6, although the amount of reflux was relatively large as compared with the comparative example, it was confirmed that the amount of coolant used was greatly reduced although the amount of reflux was large. Therefore, it was confirmed that the amount of heat recovered from the heat exchanger was also increased by 2 times to 3 times.

From the above, it can be confirmed that the production unit according to the present invention is an innovative process capable of reducing energy loss of the entire process by increasing recoverable heat and capable of improving cooling efficiency by installing a flash tank.

Experimental example 2

In performing the simulation using the above procedure, the simulation was performed by the process shown in fig. 2 in which four identical production units were coupled as raw materials, the dicarboxylic acid was terephthalic acid, the primary alcohol was 2-ethylhexanol, and the molar ratio of the two raw materials was set to 1: 2.5. The temperature of the organic layer containing the primary alcohol discharged through the organic layer line 141 was set to 95 c, and the connection position of the flash tank lower line 132 and the organic layer line 141 was changed as shown in table 2 below. The amount of the coolant consumed in the condenser 15 and the total flow rate of the steam flowing in the gas phase line 121 of the column 12 were determined, and the values in the following table 2 are relative% assuming that the comparative example 2-1 is 100%.

[ Table 2]

Referring to table 2 above, it can be confirmed that since the flash tank is installed, the flow rate of the gas phase line of the column, i.e., the upper portion, is increased, which means that the capacity of the column can be separated from the flash tank. It can be seen that the liquid phase is recirculated once in the flash tank before flowing to the condenser, thereby greatly improving cooling efficiency.

In addition, in the case of examples 2-1 to 2-6, although the amount of reflux was relatively large as compared with the comparative example, it was confirmed that the amount of coolant used was greatly reduced although the amount of reflux was large. Therefore, it was confirmed that the amount of heat recovered from the heat exchanger was also increased by 2 times to 3 times.

From the above, it can be confirmed that the production unit according to the present invention is an innovative process capable of reducing energy loss of the entire process by increasing recoverable heat and capable of improving cooling efficiency by installing a flash tank.

[ description of reference numerals or symbols ]

10: a production unit; 11: reaction device

110: a reaction vessel; 111: gas phase discharge line

112: a product line; 112': raw material injection line

12: a tower; 120: tower body

121: a gas phase line; 122: liquid phase pipeline

13: a flash tank; 130: flash tank body

131: an upper pipeline of the flash tank; 132: flash tank lower line

14: a layer separator; 140: separating tank

141: an organic layer line; 142: water layer pipeline

15: a condenser; 16: heat exchanger