KR20150145054A - Apparatus and method for purifying ethylene dichloride using waste heat - Google Patents

Abstract

The present invention relates to an apparatus and a method for purifying ethylene dichloride (EDC) using waste heat. The apparatus for purifying EDC comprises: a first distillation column into which an EDC stream is introduced and separated into three streams; a second distillation column into which a lower stream of the first distillation column is introduced and separated into at least two streams; a steam flow line into which a steam flow released to an upper part of the first distillation column is introduced; and a heat exchange unit into which the steam flow of the steam flow line is introduced and supplying heat of the steam flow to a lower part of the second distillation column. According to the present invention, a process of EDC purification in VCM manufacturing processes is improved, thereby saving energy.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for purifying ethylene dichloride using waste heat,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for purifying ethylene dichloride and a method for purifying ethylene dichloride, and more particularly, to an apparatus and a method for purifying ethylene dichloride generated in a process for producing a vinyl chloride monomer.

In general, vinyl chloride monomer (VCM) is obtained by the synthesis of ethylene (C ₂ H ₄ ) and chlorine compound (Cl ₂ , HCl). At this time, ethylene dichloride (EDC) is produced as an intermediate in the synthesis reaction, and most vinyl chloride monomers (VCM) are obtained by a cracking reaction of ethylene dichloride (EDC). Ethylene dichloride (EDC) is converted to vinyl chloride monomer (VCM) at a conversion of about 50-70% commercially through a pyrolysis reactor.

Korean Patent Laid-Open Nos. 10-2009-0036659, 10-2011-0015087 and 10-2011-0008942 disclose the above-mentioned techniques. The following reaction illustrates the main reaction in the vinyl chloride monomer (VCM) production process.

[Synthetic reaction]

C ₂ H ₄ + Cl ₂ (or HCl) → CH ₂ = CHCl, CH ₂ ClCH ₂ Cl

[Pyrolysis reaction]

CH ₂ ClCH ₂ Cl → CH ₂ = CHCl + HCl

In addition, byproducts other than vinyl chloride monomer (VCM) and ethylene dichloride (EDC) are present in the product after each reaction. Byproducts include light heavy materials such as chlorine compounds (Cl ₂ , HCl), ethylene, acetylene and methyl chloride and heavy heavy materials such as chloroprene, trichloroethane, benzene and solid carbon materials, . These by-products are purified for high purity.

Therefore, the VCM manufacturing process equipment is provided with a refining device for refining by-products, in addition to a raw material synthesizing device and a pyrolyzing device. Specifically, in the synthesis reaction, an ethylene dichloride (EDC) stream is produced, and this ethylene dichloride (EDC) stream is fed to a purification apparatus. In addition, an ethylene dichloride (EDC) stream is also produced in the pyrolysis reaction, which is also supplied to the purification apparatus.

Generally, the ethylene dichloride (EDC) stream produced in the synthesis reaction is usually purified in a purification apparatus having three distillation columns commercially. Through such distillation columns, ethylene dichloride (EDC) can be purified and recovered in high purity. In this purification process, a large amount of energy is consumed. Specifically, each of the distillation columns is supplied with a heat source for separating the components through the boiling point, and most energy is consumed in the separation process.

However, the conventional purification process of ethylene dichloride (EDC) consumes too much energy. As described above, each distillation column is supplied with a heat source for separating the components. Especially, efficient use of the heat source is not considered in such a separation process, resulting in a large amount of energy consumption.

Korea Patent Publication No. 10-2009-0036659 Korean Patent Publication No. 10-2011-0015087 Korea Patent Publication No. 10-2011-0008942

Accordingly, the present application aims to provide an improved apparatus for purifying ethylene dichloride (EDC) and a purification method thereof.

The present application specifically provides an apparatus for purifying ethylene dichloride (EDC) and a purification method capable of reducing the amount of energy used, for example, by improving the process of purifying ethylene dichloride (EDC) in the VCM production process It has its purpose.

[0002]

A first distillation column for introducing an ethylene dichloride (EDC) stream and separating into three streams;

A second distillation column for introducing a lower stream of the first distillation column and separating the lower stream into at least two streams;

A vapor flow line through which the vapor flow exiting to the top of the first distillation column flows; And

And a heat exchange unit for introducing the steam flow of the steam flow line and supplying the heat of the steam flow to a lower portion of the second distillation column.

In addition,

A first distillation step of introducing an ethylene dichloride (EDC) stream into the first distillation column and separating into three streams;

And a second distillation step of introducing the bottom stream of the first distillation column into the second distillation column and separating into at least two streams,

The second distillation step provides a method of purifying ethylene dichloride (EDC) using the heat of the steam flow flowing to the upper portion of the first distillation column as a heat source of the second distillation column.

According to the present application, the purification process of ethylene dichloride (EDC) is improved in the VCM production process, and the energy efficiency is enhanced. Specifically, according to the present application, the vapor heat generated in the first distillation column can be used as a heat source of the second distillation column to reduce energy consumption.

1 is a configuration diagram showing an apparatus for purifying ethylene dichloride (EDC) according to a first embodiment of the present application.
2 is a configuration diagram showing an apparatus for purifying ethylene dichloride (EDC) according to a second embodiment of the present application.

Hereinafter, the present application will be described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings, the same reference numerals as in the appended drawings denote the same elements, even though they are shown in different drawings.

In this specification, 'and / or' are used to mean at least one of the elements listed before and after.

In this specification, the terms "connection", "installation", and "coupling" mean that two members can be detached (joined and separated) as well as an integral structure. Specifically, the terms " connection, " " installation, " and " coupling, " A fitting method using a groove and a projection; And a fastening method using a fastening member such as a screw, a bolt, a piece, a rivet, a bracket, or the like, so that the two members are engaged and separated, and the two members are combined through welding, adhesive, , And the integral which can not be separated.

The terms "first", "second", "third", "one side", and "other side" are used herein to distinguish one element from another, But is not limited by the terms. In the following description of the present application, a detailed description of known general functions or configurations will be omitted.

As mentioned above, an ethylene dichloride (EDC) stream is produced in the process of producing a vinyl chloride monomer (VCM). In addition, such ethylene dichloride (EDC) streams have by-products, which are purified through a distillation process.

The present application relates to the purification of ethylene dichloride (EDC) as described above. Figures 1 and 2 show an apparatus for purifying ethylene dichloride (EDC) according to an exemplary embodiment of the present application.

Referring to Figures 1 and 2, an apparatus for purifying ethylene dichloride (EDC) according to the present application comprises a first distillation column 10 for introducing an ethylene dichloride (EDC) stream and separating into three streams; A second distillation column (20) for introducing the lower stream of the first distillation column (10) and separating the lower stream into at least two streams; A vapor flow line (40) for introducing a vapor flow exiting to the top of the first distillation column (10); And a heat exchange line (50) for introducing the steam flow of the steam flow line (40) and supplying the heat of the steam flow to the lower portion of the second distillation column (20).

Also according to an exemplary form of the present application, an apparatus for purifying ethylene dichloride (EDC) according to the present application is characterized in that it comprises a third distillation column 20 for introducing the bottom stream of the second distillation column 20, And a distillation column (30).

Meanwhile, the method for purifying ethylene dichloride (EDC) according to the present application comprises a first distillation step of introducing an ethylene dichloride (EDC) stream into a first distillation column 10 and separating into three streams; And a second distillation step of introducing the lower stream of the first distillation column (10) into the second distillation column (20) and separating the lower stream of the first distillation column (10) into at least two streams. At this time, the second distillation step includes a step of using the heat of the steam flow flowing to the upper part of the first distillation column 10 as a heat source of the second distillation column 20. In order to implement the method of purifying ethylene dichloride (EDC) according to the present application, a device for purifying ethylene dichloride (EDC) according to the present application can be usefully applied. However, the method of purifying ethylene dichloride (EDC) according to the present application is not limited to being implemented through the apparatus for purifying ethylene dichloride (EDC) according to the present application.

The purification apparatus and the purification method according to the present application are not limited as long as they are for purifying ethylene dichloride (EDC) generated in a vinyl chloride monomer (VCM) production process. Specifically, in the present application, the substance to be purified, i.e., the feed entering the first distillation column 10, is an ethylene dichloride (EDC) stream containing at least ethylene dichloride (EDC). Here, in the present application, the ethylene dichloride (EDC) stream may be directed to an ethylene dichloride (EDC) stream generated in a synthesis process of a vinyl chloride monomer (VCM) production process and / or a pyrolysis process, Depending on the form, the ethylene dichloride (EDC) stream generated after the synthesis process can be targeted.

In the description of the present application, vinyl chloride monomer (VCM) is abbreviated as 'VCM', and ethylene dichloride (EDC) is abbreviated as 'EDC'.

Generally, EDC streams generated in the VCM manufacturing process include various by-products in addition to EDC. The by-products may be classified into light materials that are lighter than EDC and heavy materials that are heavier than EDC. At this time, the light materials include N ₂ , which contains a chlorine compound (Cl ₂ , HCl), ethylene, acetylene, VCM and methyl chloride, and other difficult condensing materials. Examples of the heavies include chloroprene, trichloroethane, benzene, and solid carbon materials.

The present application seeks to reduce energy by separating the above light and heavy materials from the EDC stream by distillation and recovering and recycling the waste heat in the process. That is, according to the present application, the steam heat source of the first distillation column (C) that has been abandoned in the past can be reused as the distillation heat source of the second distillation column (20), and energy consumption can be reduced. In addition, purification of EDC can be efficiently achieved.

In the present application, "A stream (or A stream)" means a stream containing at least an 'A' component, which may include an 'A' component as a main component. For example, an "EDC stream" is a stream comprising at least an "EDC", a "Lights stream" and a "Heavies stream" are at least "Lights" (Heavies).

Further, in the present application, each of the distillation columns 10, 20 and 30 can be selected from a distillation column used in a distillation process in a general industrial field. At this time, the operating conditions of the distillation columns 10, 20 and 30, for example, the distillation columns 10, 20 and 30, the number and temperature of the distillation columns 10, 20 and 30, The ratio and the like are not particularly limited, and they need only be capable of continuously performing the separation process in a stabilized state.

In addition, a condenser and / or a heat exchanger (or a reflux condenser) may be installed in each of the distillation columns 10, 20 and 30. In the figure, reference symbol A denotes a condenser, and reference symbol B denotes a heat exchanger (or re-boiler). Depending on the distillation columns 10, 20 and 30, the condenser A and / or the heat exchanger B may be optionally installed or not installed. Further, the condenser A and the heat exchanger B may be constituent elements which may be omitted even if they are shown in the drawings, unless otherwise specified.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, referring to the accompanying drawings, exemplary embodiments of a purification apparatus and a purification method of an EDC according to the present application will be described together. FIG. 1 is a configuration diagram of an EDC purification apparatus according to a first embodiment of the present application, and FIG. 2 is a configuration diagram of an EDC purification apparatus according to a second embodiment of the present application.

First Embodiment

1, an EDC purification apparatus according to a first embodiment of the present application comprises a first distillation column 10; A second distillation column (20) installed behind the first distillation column (10); And a third distillation column 30 installed at the rear of the second distillation column 20. At this time, a heat exchange unit 50 is provided between the first distillation column 10 and the second distillation column 20. A steam flow line (40) is connected between the first distillation column (10) and the heat exchange unit (50).

The EDC stream is introduced into the first distillation column (10). The EDC stream introduced into the first distillation column 10 is separated and discharged through at least three streams through distillation. To this end, the first distillation column 10 has at least one feed inlet line 11 and at least three outlet lines 12, 13 and 14.

The feed inlet line 11 is provided at the front end of the first distillation column 10. Through this feed line 11, for example, the EDC stream generated in the synthesis reaction of the VCM manufacturing process is introduced. The first distillation column 10 also has three outflow lines 12,13,14 as an upper outlet line 12 installed at the top of the column 10 and a lower outlet Line 14 and a central outflow line 13 disposed in the central region of the column 10. [

In this case, in the present application, the 'central region' does not mean only the center of the column 10, which means the middle region located between the upper and lower portions of the first distillation column 10. Specifically, the central outflow line 13 may be provided between the upper portion and the lower portion of the first distillation column 10. The center outflow line 13 may be installed at a position corresponding to 2 to 8 points, or 3 to 6 points, for example, when the total height of the first distillation column 10 is '10' .

The flow exiting to the upper outlet line 12 is a low boiling vapor stream. That is, as the low-boiling steam flow having a boiling point lower than that of the EDC, a light material stream flows out through the upper outlet line 12. [ As the liquid outflow line 14, a stream of heavies having a boiling point higher than that of the EDC flows out as a liquid and / or vapor phase stream. Also, as the middle outflow line 13, most of the EDC stream having a medium boiling point flows out. At this time, the EDC stream flowing out to the central outflow line 13 is mainly composed of EDC, and the EDC stream may be recovered and then supplied to a cracking process in, for example, the VCM process.

A condenser A1 (hereinafter referred to as a "first condenser") may be installed at the upper end of the first distillation column 10. At this time, the upper outlet line 12 is connected to the front end of the first condenser A1. A first discharge line 12a and a second discharge line 12b are connected to a rear end of the first condenser A1. The condensed material in the first condenser A1 is discharged to the first discharge line 12a and the non-condensed material which is difficult to condense is discharged through the second discharge line 12b. The substance discharged to the first discharge line 12a (i.e., the condensed substance) includes, for example, HCl, ethylene, acetylene, VCM and methyl chloride. The material discharged to the second discharge line 12b (i.e., the non-condensing material) may be, for example, N ₂ .

Further, a heat exchanger B1 (hereinafter, referred to as a "first heat exchanger") is provided at the lower end of the first distillation column 10. The first heat exchanger (B1) supplies a distillation heat source for separating the EDC stream to the lower end of the first distillation column (10). In addition, the bottom stream flowing out to the bottom outlet line 14 of the first distillation column 10 is fed to the second distillation column 20. At this time, the bottom stream flowing out to the lower outlet line 14 is a Heavies flow, which contains EDC with heavy materials (Heavies).

The lower stream of the first distillation column (10) flows into the second distillation column (20). The bottom stream of the first distillation column (10) flows into the second distillation column (20) and is separated out into at least two streams. To this end, the second distillation column 20 has at least one inlet line 21 and at least two outlet lines 22,

The inlet line 21 is installed at the front end of the second distillation column 20, which is connected to the lower outlet line 14 of the first distillation column 10. The bottom stream of the first distillation column 10 flows through the inlet line 21. The second distillation column 20 also includes two outflow lines 22 and 23 and a first outflow line 22 disposed at the top of the column 20 and a second outflow line 22 disposed at the bottom of the column 20, (23).

The EDC stream flows out through the first outflow line 22 and the Heavies stream flows out through the second outflow line 23. At this time, the EDC stream flowing through the first outflow line 22 is mainly composed of EDC, which can be recovered after being condensed.

A condenser A2 (hereinafter referred to as a "second condenser") may be installed at the upper end of the second distillation column 20. [ At this time, the first outflow line 22 is connected to the front end of the second condenser A2. A first discharge line 22a and a second discharge line 22b are connected to the rear end of the second condenser A1. The condensed material in the second condenser A2 is discharged to the first discharge line 22a and the non-condensed material, which is difficult to condense, is discharged through the second discharge line 22b. At this time, the substance (that is, the condensed substance) discharged to the first discharge line 22a is the main component of EDC. Further, a heat exchanger B2 (hereinafter referred to as a "second heat exchanger") may be installed at the lower end of the second distillation column 20. [ The second heat exchanger (B2) supplies a distillation heat source for separating the flow into the inlet line (21) to the lower end of the second distillation column (20).

In addition, when the EDC purification apparatus according to the present application further includes the third distillation column 30, the flow out of the second distillation column 20 of the second distillation column 20 flows through the third distillation column 30 ). At this time, the stream flowing out to the second outflow lines 23 and 14 is a Heavies stream, which is mainly composed of Heavies, and may contain a small amount of EDC. The third distillation column 30 purifies it.

The third distillation column 30 introduces a lower stream of the second distillation column 20, that is, a stream exiting the second distillation column 23 of the second distillation column 20, Separate into two streams. To this end, the third distillation column 30 has at least one inlet line 31 and at least two outlet lines 32, 33.

The inlet line 31 is installed at the front end of the third distillation column 30, which is connected to the second outlet line 23 of the second distillation column 20. The bottom stream of the second distillation column (20) flows through this inlet line (31). The third distillation column 30 also includes two outflow lines 32 and 33 and a first outflow line 32 disposed on the top of the column 30 and a second outflow line 32 disposed on the bottom of the column 30, (33). The EDC stream flows out through the first outflow line 32 and the Heavies stream is discharged through the second outflow line 33. At this time, the EDC stream flowing through the first outflow line 32 is mainly composed of EDC, which can be recovered after being condensed. Also, the Heavies stream discharged through the second outflow line 33 is mostly heavies, which can be disposed of after cooling.

A condenser A3 (hereinafter referred to as a "third condenser") may be installed at the upper end of the third distillation column 30. [ At this time, the first outflow line 32 is connected to the front end of the third condenser A3. A first discharge line 32a and a second discharge line 32b are connected to the rear end of the third condenser A3. The condensed material in the third condenser A3 is discharged to the first discharge line 32a and the non-condensed material, which is difficult to condense, is discharged through the second discharge line 32b. At this time, the substance discharged to the first discharge line 32a (that is, the condensed substance) is the main component of EDC. Further, a heat exchanger B3 (hereinafter referred to as a 'third heat exchanger') may be installed at the lower end of the third distillation column 30. [ The third heat exchanger (B3) supplies a distillation heat source for separating the flow into the inlet line (31) to the lower end of the third distillation column (30).

The steam flow line 40 introduces a vapor stream flowing to the top of the first distillation column 10 and supplies it to the heat exchange unit 50. That is, one side of the vapor flow line 40 is connected to the upper part of the first distillation column 10, and the other side is connected to the heat exchange unit 50. As described above, the upper portion of the first distillation column 10 is provided with an upper outlet line 12 through which the steam flow exits, which can be connected to the upper outlet line 12 as above have. Figure 1 shows this connection structure.

The vapor stream flowing out to the top of the first distillation column 10 passes through the vapor flow line 40 and is supplied to the heat exchange unit 50. And the heat exchange unit 50 introduces the steam flow of the steam flow line 40 and supplies the heat of the steam flow to the lower portion of the second distillation column 20 through heat exchange.

Thus, according to the present application, the heat of the vapor stream generated in the first distillation column 10 is not discarded but is reused as a distillation heat source in the second distillation column 20. [ As a result, energy consumption in the process is reduced. That is, part or all of the heat source to be supplied in the second heat exchanger (B2) of the second distillation column (20) is replaced by heat of the vapor flow generated in the first distillation column (10)

In the present application, the heat exchange unit 50 is not particularly limited as long as it can supply the heat of the steam flow flowing out of the first distillation column 10 to the second distillation column 20 through heat exchange. The heat exchange unit 50 may include at least one heat exchanger 51, according to an exemplary embodiment. The heat exchanger 51 may have a structure in which a heating medium flows, for example. Also, as illustrated in FIG. 1, the heat exchanger (51) may be connected to a heat exchange line (52) (53) through which the heating medium passes. At this time, the heat exchange lines 52 and 53 are connected to the lower end of the second distillation column 20, which removes the heat of the steam flow in the heat exchanger 51, And a return line 53 through which the heat medium heated by supplying heat to the lower portion of the second distillation column 20 passes.

Further, according to an exemplary embodiment, it may further comprise a reflux line 60 for supplying the vapor stream passing through the heat exchange unit 50 to the condenser A1 of the first distillation column 10. [ Specifically, the steam flow passing through the heat exchange unit 50 can be processed separately, but is supplied to the first condenser A1 through the reflux line 60, and then condensed in the first condenser A1, It is better to be processed.

Second Embodiment

Hereinafter, a second embodiment of the present application will be described. 2 shows an EDC purification apparatus according to a second embodiment of the present application.

In describing the second embodiment of the present application, terms and reference numerals used in the same manner as in the first embodiment denote the same functions, and a detailed description thereof will be omitted. If there is a part which is not described in detail below, this is as described in the first embodiment.

According to a second embodiment of the present application, at least the structure and operating conditions of the second distillation column 20 are improved.

2, the EDC purification apparatus according to the second embodiment of the present application includes the first distillation column 10, the second distillation column 20, the third distillation column 30, the steam A flow line 40 and a temperature lowering section 25 including a heat exchange unit 50 and dropping the lower temperature of the second distillation column 20. [

In the present application, the temperature lower portion 25 is not particularly limited as long as it can lower at least the lower temperature (T2) of the second distillation column 20. According to an exemplary embodiment of the present application, the temperature drop can be advanced by lowering the internal pressure (P) of the second distillation column (20). Specifically, the temperature lower portion 25 may include pressure drop means capable of lowering the internal pressure P of the second distillation column 20. [ In one example, the temperature lower portion 25 may comprise a vacuum pump as a pressure drop means. In the drawing, a vacuum pump is exemplarily shown as the temperature lower portion 25. However, in the present application, the temperature lower portion 25 is not limited to a vacuum pump, and is not particularly limited as long as it can lower the lower temperature (T2) of the second distillation column 20.

Further, the position and the number of the temperature lower portions 25 are not limited. The temperature lower portion 25 may be installed inside the second distillation column 20 or may be located outside the second distillation column 20 and connected to the second distillation column 20, For example, one or more than two. The temperature lower portion 25 can be connected to one or more of the sidewalls of the second distillation column 20 by using a vacuum pump in one example. At this time, the vacuum pump can be connected and installed as close as possible to the side wall of the second distillation column 20 so as to provide the maximum depressurization (suction force).

Under normal steady state conditions, the upper temperature (T1) of the first distillation column (10) and the lower temperature (T2) of the second distillation column (20) can be operated at similar levels. In this case, however, effective heat exchange may be difficult.

Thus, according to the present embodiment, when the upper temperature T1 of the first distillation column 10 and the lower temperature T2 of the second distillation column 20 are operated at similar levels, By lowering at least the lower temperature (T2) of the second distillation column (20) through the lower part (25) of the steel, effective heat exchange can be achieved, which is more effective for energy saving.

According to an exemplary embodiment, the first distillation column 10 and the second distillation column 20 are preferably operated to satisfy the following equations.

[Mathematical Expression]

ΔT ≥ 3 ° C

T1 is the upper temperature of the first distillation column 10 and T2 is the lower temperature of the second distillation column 20. In the above equation,

Specifically, the lower temperature T2 of the second distillation column 20 is artificially reduced so that the upper temperature T1 of the first distillation column 10 is lower than the lower temperature T2 of the second distillation column 20 It is better to operate with high holding. As a result, the heat exchange efficiency is increased, and the heat of the steam flow flowing out to the upper portion of the first distillation column 10 can be more efficiently used as the heat source of the second distillation column 20. [ Considering this point,? T of the above equation may be 5 ° C or more. More specifically,? T in the above equation may be 5 to 50 ° C, 5 to 40 ° C, 5 to 30 ° C, or 5 to 25 ° C, and more specifically 10 to 50 ° C, To 30 < 0 > C, or 10 to 25 < 0 > C.

In order to lower the lower temperature T2 of the second distillation column 20, the lower temperature of the second distillation column 20 may be adjusted so as not to adversely affect the separation efficiency of the second distillation column 20 T2 should be maintained above the upper temperature (T3) of the second distillation column (20). That is, T2> T3 must be maintained in the drawing. With this in mind, it may be desirable that the lowering of the lower temperature (T2) proceeds through the internal pressure (P) drop of the second distillation column (20) as illustrated above. Specifically, when the internal pressure P is reduced, the upper temperature T3 and the lower temperature T2 are lowered at an equal ratio, so that T2> T3 can be maintained by a simple operation.

According to an exemplary embodiment of the present application, the upper temperature (T1) of the first distillation column 10 may be maintained at, for example, 90 ° C or higher, more specifically 90 ° C to 120 ° C. In addition, the lower temperature T2 of the second distillation column 20 can be maintained at 115 deg. C or less, for example, 70 deg. C to 115 deg. C through, for example, the internal pressure P drop. The lower temperature (T2) of the second distillation column 20 may be maintained at 75 占 폚 to 115 占 폚, 75 占 폚 to 92 占 폚, 75 占 폚 to 90 占 폚, or 75 占 폚 to 85 占 폚 for a more specific example.

For example, the lower temperature (T2) of the second distillation column 20 can be lowered to the normal temperature of 110 ° C to 90 ° C. However, when the lower temperature (T2) of the second distillation column (20) is lowered, the EDC loss may occur in the second distillation column (20) And is purified and recovered in the third distillation column (30).

In addition, the internal pressure P of the second distillation column 20 can be advantageously lowered to keep it low. The internal pressure P of the second distillation column 20 can be maintained at, for example, 2 kg / cm 2 or less. The lower limit of the internal pressure (P) of the second distillation column (20) is not particularly limited, but may be, for example, 0.1 kg / cm 2 or more. Specifically, the internal pressure P of the second distillation column 20 may be maintained at 0.1 to 2 kg / cm 2. The internal pressure P of the second distillation column 20 may be maintained at 0.1 to 1 kg / cm 2 or 0.1 to 0.5 kg / cm 2, for example.

Third Embodiment

As described above, the vapor flow exiting the upper outlet line 12 of the first distillation column 10 flows into the vapor flow line 40. At this point, all of the vapor flow exiting to the upper outlet line 12 may flow into the vapor flow line 40, or a portion thereof may flow into the vapor flow line 40.

The heat of the vapor stream generated in the first distillation column 10 is also reused as a distillation heat source in the second distillation column 20 through the vapor flow line 40 and the heat exchange unit 50, Depending on the embodiment, the heat of the vapor stream generated in the second distillation column 30 can also be reused. That is, the heat of the steam flow generated in the second distillation column 30 can be reused as the distillation heat source of the third distillation column 30. [ More specifically, an EDC purification apparatus according to another embodiment of the present application includes a second vapor flow line (not shown) for introducing a vapor flow exiting to the upper portion of the second distillation column 20; And a second heat exchange unit (not shown) for introducing the vapor stream of the second vapor flow line and supplying the heat of the vapor flow to the lower portion of the third distillation column 30 through heat exchange. In addition, in the case of the third distillation column 30, the temperature drop as described for the second distillation column 20 can be achieved.

According to the present application described above, the efficiency of energy can be increased by the improved purification process as described above. Specifically, the vapor heat source of the first distillation column 10 can be used as a heat source of the second distillation column 20 to reduce energy consumption, and the EDC can be efficiently purified with high purity.

On the other hand, in the present application, the lines through which the components and the streams flow in and out are not limited as long as the fluid can pass therethrough, and they can be selected from a metal pipe, a plastic pipe, and the like. In addition, each of the lines includes a flexible one. In addition, a pump or the like for smoothly flowing the components and streams may be installed on the lines, or a valve for controlling the flow (blocking and / or controlling the flow rate) may be installed.

Hereinafter, examples and comparative examples of the present application will be exemplified. The following examples and comparative examples are provided by way of example only to aid understanding of the present application, and the technical scope of the present application is not limited thereby. Further, the following comparative examples are presented for comparison with the examples, and do not mean the prior art.

[Comparative Example]

The EDC stream generated in the VCM synthesis process was purified using a purification apparatus equipped with three distillation columns. Each distillation column was operated under steady-state conditions, and the operating conditions of the main column are shown in Table 1 below. Further, the heat energy consumed in each column was measured, and the results are shown together in Table 1 below.

[Example]

The EDC stream generated in the VCM synthesis process was purified, and the heat of the steam flow generated in the first distillation column was purified using the apparatus as shown in FIG. 2 as a heat source of the second distillation column. Further, in the purification process according to the present embodiment, the temperature drop of the second distillation column 20 was induced by the reduced pressure. The operating conditions of the main column are shown in Table 1 below. Further, the heat energy consumed in each column was measured, and the results are shown together in Table 1 below.

                    <Energy consumption> Remarks P
(kg / cm2) T1 T2 Q ₁ Q ₂ Q ₃ Q _T Savings
(? Q) Comparative Example
0.6 96.4 DEG C 93.8 ° C 5.23 3.56 0.30 9.09 - Example
0.2 96.4 DEG C 77.0 DEG C 5.23 0 0.35 5.58 3.51
- P: internal pressure of the second distillation column (kg / cm2)
- T1: the upper temperature of the first distillation column (占 폚)
- T2: lower temperature of the second distillation column (占 폚)
- Q ₁ : thermal energy (Gcal / hr) supplied to the first distillation column
- Q ₂ : the thermal energy (Gcal / hr) supplied to the second distillation column
- Q ₃ : the thermal energy (Gcal / hr) supplied to the third distillation column
- Q _T : Q ₁ + Q ₂ + Q ₃

As shown in Table 1 above, the lower temperature (T2) drop is induced through the internal pressure (P) drop of the second distillation column (20) and the second distillation column 10 is used as the heat source (Q ₂ ) of the second distillation column 20, the energy consumption can be reduced.

10: first distillation column 20: second distillation column
30: third distillation column 40: vapor flow line
50: heat exchange unit 60: reflux line

Claims (16)

A first distillation column into which the ethylene dichloride stream is introduced and which is separated into three streams;
A second distillation column for introducing a lower stream of the first distillation column and separating the lower stream into at least two streams;
A vapor flow line through which the vapor flow exiting to the top of the first distillation column flows; And
And a heat exchange unit for introducing the vapor stream of the vapor flow line and supplying the heat of the vapor flow to a lower portion of the second distillation column.
The method according to claim 1,
Further comprising a reflux line for supplying the vapor stream passing through the heat exchange unit to the condenser of the first distillation column.
The method according to claim 1,
Further comprising a temperature lowering part for lowering the lower temperature of the second distillation column.
The method of claim 3,
Wherein the temperature drop comprises pressure drop means for lowering the internal pressure of the second distillation column.
5. The method of claim 4,
Characterized in that said pressure drop means comprise a vacuum pump connected to a second distillation column.
The method according to claim 1,
Wherein the first distillation column and the second distillation column are operated so as to satisfy the following equation.
[Mathematical Expression]
ΔT ≥ 3 ° C
(In the above equation,? T = T1 - T2, T1 is the upper temperature of the first distillation column, and T2 is the lower temperature of the second distillation column.)
The method according to claim 6,
Wherein? T in the above equation is 5 to 30 占 폚.
The method according to claim 6,
Characterized in that the upper temperature (T1) of the first distillation column is maintained at 90 占 폚 to 120 占 폚 and the lower temperature (T2) of the second distillation column is maintained at 75 占 폚 to 115 占 폚. Device.
5. The method of claim 4,
Wherein the second distillation column has an internal pressure of 0.1 to 2 kg / cm &lt; 2 &gt; by pressure drop.
A first distillation step of introducing the ethylene dichloride stream into the first distillation column and separating into three streams;
And a second distillation step of introducing the bottom stream of the first distillation column into the second distillation column and separating into at least two streams,
Wherein the second distillation step uses heat of the vapor stream flowing to the upper portion of the first distillation column as a heat source of the second distillation column.
11. The method of claim 10,
Wherein the second distillation step is carried out by lowering the lower temperature of the second distillation column.
11. The method of claim 10,
Wherein the first distillation column and the second distillation column are operated so as to satisfy the following formula:
[Mathematical Expression]
ΔT ≥ 3 ° C
(In the above equation,? T = T1 - T2, T1 is the upper temperature of the first distillation column, and T2 is the lower temperature of the second distillation column.)
13. The method of claim 12,
Wherein? T in the above equation is 5 to 30 占 폚.
13. The method of claim 12,
Characterized in that the upper temperature (T1) of the first distillation column is maintained at 90 占 폚 to 120 占 폚 and the lower temperature (T2) of the second distillation column is maintained at 75 占 폚 to 115 占 폚. Way.
12. The method of claim 11,
Wherein the lower temperature drop of the second distillation column proceeds through an internal pressure drop.
16. The method of claim 15,
Wherein the inner pressure of the second distillation column is maintained at 0.1 to 2 kg / cm &lt; 2 &gt;.

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