KR20220034428A - Conjugated diene monomer recovery method and conjugated diene monomer recovery apparatus - Google Patents

Abstract

The present invention relates to a method for recovering a conjugated diene-based monomer. Particularly, the method according to the present invention includes the steps of: (S10) supplying a gaseous feed stream containing a nitrile-based monomer, conjugated diene-based monomer and water to a first condenser to separate the feed stream into a bottom discharge stream containing the nitrile-based monomer and water and a top discharge stream containing the nitrile-based monomer and conjugated diene-based monomer; (S20) supplying the top discharge stream of the first condenser to the bottom of an absorption tower, and supplying the solvent to the top of the absorption tower; and (S30) discharging the bottom discharge stream containing the nitrile-based monomer dissolved in the solvent from the absorption tower, and supplying the top discharge stream containing the conjugated diene-based monomer to a purification unit. According to the present invention, it is possible to recover the conjugated diene-based monomer with high purity and to reduce the load applied to a waste water treatment system.

Description

The recovery method and recovery device of a conjugated diene-based monomer

The present invention relates to a method and a device for recovering a conjugated diene-based monomer, and more particularly, to a method and device for recovering a conjugated diene-based monomer from a recovery gas of a polymerization reaction containing a conjugated diene-based monomer and a nitrile-based monomer is about

In general, in the manufacturing process of NBL (Nitrile Butadiene Rubber Latex), in the aqueous polymer solution obtained after the polymerization of nitrile-based monomers and butadiene, not only the acrylonitrile-butadiene copolymer (NB) but also about 7% of the monomers added to the reaction are unreacted. Monomers and C4 impurities are by-products.

By supplying this polymer aqueous solution to the stripper and vacuum stripping, the unreacted monomer and C4 impurities are stripped in a gaseous state to the upper part of the stripper, and the acrylonitrile-butadiene copolymer and water are discharged to the lower part, The final NBL product is produced through the commercialization process of the bottom effluent stream.

On the other hand, the gas stripped to the upper part of the stripper separates unreacted butadiene into a gas phase through condensation and compression processes, and the residues are recovered and treated as wastewater. At this time, the separated unreacted butadiene is incinerated in its entirety, and it is difficult to respond to environmental regulations caused by greenhouse gases and tVOC (Total Volatile Organic Compounds) generated in the process, as well as the cost of loss of unreacted butadiene. A significant problem exists.

Accordingly, in order to recover unreacted butadiene and reuse it for polymerization, butadiene must be purified by removing C4 impurities such as cis-butane and trans-butane through a purification process using extractive distillation of butadiene. However, in this case, unreacted butadiene and C4 impurities, as well as unreacted acrylonitrile, remain in the gas separated from the upper part of the stripper to be dissolved in the extraction solvent during the extractive distillation process and accumulated, or for the catalyst layer present in the extractive distillation column There was a problem in that long-term operation of the purification process was impossible while acting as a catalyst poison.

KR 1701506 B1

The problem to be solved in the present invention is to purify the recovered gas of the polymerization reaction including the conjugated diene-based monomer and the nitrile-based monomer in order to solve the problems mentioned in the technology that is the background of the present invention, to obtain a conjugated diene-based monomer It aims to reduce the load on the wastewater treatment facility by recovering it in high purity and reducing the content of the conjugated diene-based monomer monomer discharged into the wastewater.

According to an embodiment of the present invention for solving the above problems, the present invention supplies a gaseous feed stream containing a nitrile-based monomer, a conjugated diene-based monomer, and water to the first condenser to convert the nitrile-based monomer and water Separating the bottom discharge stream including, and the top discharge stream containing the nitrile-based monomer and the conjugated diene-based monomer (S10); supplying the upper discharge stream of the first condenser to the lower portion of the absorption tower, and supplying the solvent to the upper portion of the absorption tower (S20); Discharging the bottom discharge stream containing the nitrile-based monomer dissolved in the solvent from the absorption tower, and supplying the top discharge stream containing the conjugated diene-based monomer to the purification unit (S30) of the conjugated diene-based monomer A method of recovery is provided.

In addition, the present invention is a gaseous feed stream containing a nitrile-based monomer, a conjugated diene-based monomer and water is supplied, a bottom discharge stream containing a nitrile-based monomer and water, and a nitrile-based monomer and a conjugated diene-based monomer a condenser that discharges the overhead effluent stream; Absorption for receiving the upper discharge stream of the condenser to the lower part, receiving the solvent to the upper part, and discharging the lower discharge stream containing the nitrile-based monomer dissolved in the solvent and the upper discharge stream containing the conjugated diene-based monomer tower; and a purification unit receiving the upper discharge stream of the absorption tower to purify the conjugated diene-based monomer.

Through the recovery method and recovery device of the conjugated diene-based monomer according to the present invention, the recovery gas of the polymerization reaction containing the conjugated diene-based monomer and the nitrile-based monomer is purified, the conjugated diene-based monomer is recovered in high purity and discharged as wastewater It is possible to reduce the load on the wastewater treatment facility by lowering the content of the conjugated diene-based monomer monomer.

1 is a process flow diagram showing a treatment flow of a conjugated diene-based monomer and wastewater from a polymerization reaction of a conventional nitrile-based monomer and a conjugated diene-based monomer.
2 is a process flow diagram illustrating a method for recovering a conjugated diene-based monomer from a recovered gas generated from a polymerization reaction of a nitrile-based monomer and a conjugated diene-based monomer according to an embodiment of the present invention.
3 is a process flow chart specifically illustrating a method for recovering a conjugated diene-based monomer according to an embodiment of the present invention.

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.

In the present invention, the term "upper" means a portion corresponding to a height of 50% or more from the total height of the device in the container, and "lower" means a portion corresponding to a height of less than 50% from the total height of the container or device. can

In the present invention, the term 'C# impurity' in which '#' is a positive integer denotes an impurity including all hydrocarbons having # carbon atoms. Accordingly, the term 'C4 impurity' may mean an impurity comprising a hydrocarbon having 4 carbon atoms.

In the present invention, the term 'stream' may mean a flow of a fluid in a process, and may also mean a fluid itself flowing in a pipe. Specifically, the 'stream' may mean both the fluid itself and the flow of the fluid flowing within a pipe connecting each device. In addition, the fluid may refer to a gas or a liquid.

Hereinafter, the present invention will be described in more detail with reference to FIGS. 1 to 3 in order to help the understanding of the present invention.

According to the present invention, a method for recovering a conjugated diene-based monomer is provided. In the method for recovering the conjugated diene-based monomer, a gaseous feed stream containing a nitrile-based monomer, a conjugated diene-based monomer, and water is supplied to the first condenser 100, and a lower discharge stream containing the nitrile-based monomer and water; Separating the overhead effluent stream containing the , nitrile-based monomer and the conjugated diene-based monomer (S10); supplying the upper discharge stream of the first condenser 100 to the lower portion of the absorption tower 200, and supplying the solvent to the upper portion of the absorption tower 200 (S20); Discharging the bottom discharge stream containing the nitrile-based monomer dissolved in the solvent from the absorption tower 200, and supplying the upper discharge stream containing the conjugated diene-based monomer to the purification unit 300 (S30) may include

According to an embodiment of the present invention, the gaseous feed stream may be discharged from the reactor 10 for polymerizing the nitrile-based monomer and the conjugated diene-based monomer.

As a specific example, the gaseous feed stream is a nitrile-based monomer, a conjugated diene-based monomer, water, and a nitrile-based monomer-conjugated diene-based monomer from the discharge stream of the reactor 10 including water and a nitrile-based monomer-conjugated diene-based monomer copolymer. It may be produced after recovering the copolymer.

As a more specific example, the gaseous feed stream may be a top discharge stream of the stripper 20 discharged from the polymerization process of the nitrile-based monomer-conjugated diene-based monomer copolymer to be described later. Hereinafter, a polymerization process of the nitrile-based monomer-conjugated diene-based monomer copolymer will be described with reference to FIG. 2 .

The polymerization process of the nitrile-based monomer-conjugated diene-based monomer copolymer includes: supplying a nitrile-based monomer and a conjugated diene-based monomer to the reactor 10 to obtain an aqueous polymer solution (S1); By supplying the polymer aqueous solution to the stripper 20, the gaseous top discharge stream containing unreacted monomers and water from the stripper 20, and a nitrile-based monomer-conjugated diene-based monomer copolymer and water. separating the bottom effluent stream (S2); and passing the lower discharge stream (not shown) of the stripper 20 through a product processing unit (not shown) to obtain a high-purity nitrile-based monomer-conjugated diene-based monomer copolymer (S3). .

At this time, in the step (S2), the upper discharge stream of the gas phase of the stripper 20 is, as described above, as a gaseous feed stream of the method for recovering the conjugated diene-based monomer according to the present invention, the first condenser (100) can be supplied.

According to an embodiment of the present invention, the stripper 20 (stripper) may be a device in which a stripping process is performed, and the stripping may mean separating and removing a gas dissolved in a liquid. there is. For example, direct contact with steam, an inert gas or air, etc., may be performed by a method such as heating and pressurization, and in the present specification, the stripping may be used in the same sense as stripping or dissipation.

According to an embodiment of the present invention, the nitrile-based monomer includes at least one selected from the group consisting of acrylonitrile, methacrylonitrile, fumaronitrile, α-chloronitrile and α-cyanoethyl acrylonitrile can, but is not limited thereto. As a specific example, the nitrile-based monomer may be acrylonitrile, and in this case, the conjugated diene-based monomer can be easily obtained with high purity from the upper discharge stream of the absorption tower 200 to be described later.

According to an embodiment of the present invention, the conjugated diene-based monomer is 1,3-butadiene, 1,4-butadiene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1 and may include at least one selected from the group consisting of ,3-pentadiene, piperylene, 3-butyl-1,3-octadiene, 2-phenyl-1,3-butadiene, and isoprene, but is not limited thereto. . As a specific example, the conjugated diene-based monomer may be 1,3-butadiene or 1,4-butadiene, and accordingly, the copolymer produced by the polymerization reaction is an acrylonitrile-butadiene copolymer, that is, NBL (Nitrile Butadiene Rubber (NBL)). Latex).

In general, in the aqueous polymer solution obtained after the polymerization reaction of the nitrile-based monomer and the conjugated diene-based monomer, not only the nitrile-based monomer-conjugated diene-based monomer copolymer, but also about 7% of the unreacted monomer compared to the monomer introduced into the reactor 10, and C4 impurities are generated.

As in the step (S2), the polymer aqueous solution is supplied to the stripper 20 and stripped through vacuum heating, thereby stripping the unreacted monomer and C4 impurities in a gaseous state to the upper part of the stripper 20, After discharging the nitrile-based monomer-conjugated diene-based monomer copolymer and water to the bottom, the final NBL product is manufactured through the commercialization process of the bottom discharge stream.

Meanwhile, the gas stripped to the upper part of the stripper 20 separates unreacted conjugated diene-based monomers into a gas phase through condensation and compression processes, and the residues are recovered and treated as wastewater. At this time, the separated unreacted conjugated diene-based monomer is incinerated in its entirety, and not only is it difficult to respond to environmental regulations due to greenhouse gases and tVOC (Total Volatile Organic Compounds) generated in this process, but also unreacted conjugated diene There is a significant problem in the cost of loss of the system monomer.

Accordingly, in the prior art, C4 impurities such as cis-butane and trans-butane were removed through a purification process using extractive distillation of unreacted conjugated diene monomers to recover unreacted conjugated diene-based monomers and reuse them for polymerization. Although it was attempted to purify the reaction conjugated diene-based monomer, in this case, unreacted conjugated diene-based monomer and C4 impurities as well as unreacted nitrile-based monomer remain in the gas separated from the upper portion of the stripper 20, so that the extraction solvent in the extractive distillation process There was a problem in that long-term operation of the purification process was impossible while it was dissolved and accumulated in the extract or acted as a catalyst poison for the catalyst layer existing in the extractive distillation column.

Therefore, in the present invention, the upper discharge stream of the gaseous phase of the stripper 20 is supplied as the gaseous feedstream of the method for recovering the conjugated diene-based monomer according to the present invention, enabling long-term operation of the purification process of the conjugated diene-based monomer By doing so, it is intended to recover the highly purified conjugated diene-based monomer and reduce the loss of the conjugated diene-based monomer generated during the incineration process.

According to an embodiment of the present invention, in the method for recovering a conjugated diene-based monomer according to the present invention, a gaseous feed stream containing a nitrile-based monomer, a conjugated diene-based monomer and water is supplied to the first condenser 100, Separating the bottom discharge stream including the nitrile monomer and water and the top discharge stream including the nitrile monomer and the conjugated diene monomer (S10) may include.

As described above, the gaseous feed stream is a nitrile-based monomer-conjugated diene-based monomer copolymer from the exhaust stream discharged from the reactor 10 for polymerizing the nitrile-based monomer and the conjugated diene-based monomer, and then the remaining nitrile It may be the discharge stream of the reactor 10 including the monomer-based monomer, the conjugated diene-based monomer and water.

In the step (S10), the gaseous feed stream is supplied to the first condenser 100, the liquid lower discharge stream containing the condensed nitrile-based monomer and water, and the non-condensed nitrile-based monomer and the conjugated diene-based monomer It may be a step of separating into a gaseous top discharge stream comprising

At this time, the liquid bottom discharge stream of the first condenser 100 may be recovered and treated as wastewater.

According to an embodiment of the present invention, in the method for recovering the conjugated diene-based monomer according to the present invention, the upper discharge stream of the first condenser 100 is supplied to the lower portion of the absorption tower 200, and the solvent is supplied to the absorption tower It may include a step (S20) of supplying to the upper portion of (200).

In the step (S20), the upper exhaust stream of the gas phase of the first condenser 100 including the nitrile-based monomer and the conjugated diene-based monomer is supplied to the lower portion of the absorption tower 200, and the solvent is applied to the upper portion of the absorption tower 200 As a step of supplying to the absorbing tower 200, a counter flow contact may occur between the liquid solvent in the absorption tower 200 and the gaseous top discharge stream of the first condenser 100 due to a difference in density.

In this process, the nitrile-based monomer included in the upper discharge stream of the gas phase of the first condenser 100 may be selectively dissolved in the solvent and discharged to the lower portion of the absorption tower 200, and may not be dissolved in the solvent. The gaseous conjugated diene-based monomer may flow upward and be discharged to the upper portion of the absorption tower 200 . The bottom discharge stream of the absorption tower 200 may be recovered together with the liquid bottom discharge stream of the first condenser 100 and treated as wastewater.

In this case, the solvent may be water, and in particular, when the solvent is water, the nitrile-based monomer is acrylonitrile, and the conjugated diene-based monomer is butadiene, the solubility in water is about 70 times higher than that of butadiene. There is an effect that the removal of ronitrile is easy.

In addition, the solvent may be supplied to the upper portion of the absorption tower 200 after passing through a heat exchanger (not shown), if necessary.

According to an embodiment of the present invention, a liquid stream condensed by passing the upper discharge stream of the absorption tower 200 through the second condenser 210 may be supplied to the purification unit 300 . This may be for an easy purification process in the subsequent purification unit 300 .

According to an embodiment of the present invention, the crude conjugated diene condensed from the second condenser 210 may be stored in the crude conjugated diene storage unit 220 . As such, the stored crude conjugated diene may be discharged from the crude conjugated diene storage unit 220 and supplied to the refining unit 300 as needed, or a portion of the crude conjugated diene may be incinerated if necessary. For example, when the conjugated diene-based monomer is not condensed from the second condenser 210 or the nitrile-based monomer is contained in excess from the upper portion of the absorption tower 200 depending on circumstances, the 300 is supplied to the purification unit. Without it, some incineration can be done.

According to an embodiment of the present invention, the upper discharge stream of the first condenser 100 may be passed through two successive compressors 110 and 120 and then supplied to the lower portion of the absorption tower 200 .

In this case, the nitrile-based monomer contained in the upper discharge stream of the first condenser 100 may be compressed and liquefied to be discharged to the lower discharge stream of the two compressors 110 and 120 . At this time, the bottom discharge stream of the two compressors 110 and 120 is recovered together with the above-described bottom discharge stream of the absorption tower 200 and the liquid bottom discharge stream of the first condenser 100 to be treated as wastewater. can

In this way, when the upper discharge stream of the first condenser 100 is passed through the two compressors 110 and 120 , the nitrile-based discharge stream is contained in the upper discharge stream of the second compressor 120 supplied to the absorption tower 200 . By reducing the content of the monomer, it is possible to improve the separation efficiency of the conjugated diene-based monomer in the absorption tower (200).

The two compressors 110 and 120 may include a first compressor 110 and a second compressor 120 in series, and the operating pressure of the first compressor 110 is 0.1 to 0.5 kgf/cm ² (g), and the operating pressure of the second compressor 120 may be 1 to 5 kgf/cm ² (g).

For example, the operating pressure of the first compressor 110 may be 0.2 to 0.4 kgf/cm ² (g), or 0.25 to 0.35 kgf/cm ² (g), and the operation of the second compressor 120 The pressure may be from 2 to 4 kgf/cm ² (g), or from 2.5 to 4.5 kgf/cm ² (g). When the two compressors 110 and 120 are operated within this range, the content of the nitrile-based monomer in the upper exhaust stream of the second compressor 120 is minimized, and unnecessary operating pressure is not used, thereby reducing operating costs and energy. can reduce

According to an embodiment of the present invention, the supply temperature of the solvent supplied to the upper portion of the absorption tower 200 may be 20 to 40 ℃, or 25 to 35 ℃. When the supply temperature of the solvent is 20 ° C. or higher, there is an effect of improving the recovery rate of the conjugated diene-based monomer recovered from the upper portion of the absorption tower 200 due to the lowering of the solubility of the conjugated diene-based monomer, and the solvent is stored at room temperature. Since it can be supplied, there is an advantage that a separate solvent cooling device is unnecessary. On the other hand, when the supply temperature of the solvent is 40° C. or less, the solubility of the nitrile-based monomer in the solvent is maximized, and unnecessary waste of energy for temperature increase can be prevented.

According to an embodiment of the present invention, the upper discharge stream of the first condenser 100 supplied to the lower portion of the absorption tower 200 (when passing through two compressors, the upper discharge of the second compressor 120 ) stream), the ratio of the feed flow rate of the solvent supplied to the upper portion of the absorption tower 200 to the feed flow rate may be 2 to 5, or 3 to 4. When the ratio of the supply flow rate is 2 or more, the content of the nitrile-based monomer discharged to the upper portion of the absorption tower 200 can be minimized, and when the ratio of the supply flow rate is 5 or less, the bottom of the absorption tower 200 is discharged Since the content of the conjugated diene-based monomer discharged to the stream can be minimized, there is an effect of improving the recovery rate of the conjugated diene monomer recovered from the upper portion of the absorption tower 200 .

According to an embodiment of the present invention, the operating pressure of the absorption tower 200 may be 1 to 4 kgf/cm ² (g), or 2.5 to 3.5 kgf/cm ² (g). When the operating pressure is 1 kgf/cm ² (g) or more, the content of the nitrile-based monomer discharged to the upper portion of the absorption tower 200 can be minimized, and the operating pressure is 4 kgf/cm ² (g) or less In this case, the content of the conjugated diene-based monomer discharged to the lower discharge stream of the absorption tower 200 can be minimized, thereby improving the recovery rate of the conjugated diene monomer recovered from the upper portion of the absorption tower 200 .

In addition, as described above, after the operation of the second compressor 120 of 2 to 4 kgf/cm ² (g), when the absorption tower 200 is operated at the operating pressure in the above range, an additional compressor is not required, so the efficiency of the process This can be improved. In addition, when the absorption tower 200 is operated at the operating pressure in the above range, the conjugated diene-based monomer in the subsequent condenser 210 can be easily condensed at 20 to 40° C., which is the discharge temperature from the absorption tower 200. Therefore, there is an advantage that an additional cooling device is unnecessary.

For example, after passing the upper discharge stream of the first condenser 100 through two successive compressors 110 and 120 , it is supplied to the absorption tower 200 and supplied to the upper portion of the absorption tower 200 . The supply temperature of the solvent to be used is 20 to 40 °C, and is supplied to the upper portion of the absorption tower 200 with respect to the supply flow rate of the upper discharge stream of the second compressor 120 supplied to the lower portion of the absorption tower 200 The ratio of the supply flow rate of the solvent is 2 to 5, and when the operating pressure of the absorption tower 200 is 1 to 4 kgf/cm ² (g), the first condenser 100 supplied to the absorption tower 200 It is possible to minimize the energy for compressing the overhead effluent stream of There is an effect of maximizing the recovery rate of the conjugated diene-based monomer and the removal rate of the nitrile-based monomer in the upper discharge stream of the absorption tower 200 .

According to an embodiment of the present invention, the bottom discharge stream containing the nitrile-based monomer dissolved in the solvent is discharged from the absorption tower 200, and the upper discharge stream containing the conjugated diene-based monomer is purified by the purification unit 300 . It may include a step of supplying (S30).

In the step (S30), as described above, the nitrile-based monomer contained in the upper exhaust stream of the gas phase of the first condenser 100 may be selectively dissolved in the solvent and discharged to the lower portion of the absorption tower 200, , the conjugated diene-based monomer in the gas phase that is not dissolved in the solvent may flow upward and be discharged to the upper portion of the absorption tower 200 .

At this time, the recovery rate of the conjugated diene-based monomer in the upper discharge stream of the absorption tower 200 with respect to the gaseous feed stream supplied to the first condenser 100 is 99.5% or more, 99.5 to 99.9%, or 99.5 to It can be 99.7%.

In addition, the removal rate of the nitrile-based monomer in the upper discharge stream of the absorption tower 200 with respect to the gaseous feed stream supplied to the first condenser 100 is 99.90% or more, 99.90 to 99.99%, or 99.92 to 99.95% can be

Thereafter, the overhead discharge stream of the absorption tower 200 is supplied to the purification unit 300 and C4 impurities remaining in the top discharge stream of the absorption tower 200, for example, cis-butane or By removing trans-butane, the purity of the conjugated diene-based monomer may be improved.

At this time, the purification unit 300 may purify the conjugated diene-based monomer through extractive distillation, vacuum distillation, or vacuum distillation, but is not limited to the above-described purification method. As a specific example, the purification may be performed through extractive distillation, and in this case, the separation efficiency of C4 impurities from the upper discharge stream of the absorption tower 200 is excellent.

On the other hand, when the nitrile-based monomer is added in the extractive distillation process, it is dissolved and accumulated in the extraction solvent during the extractive distillation process, or acts as a catalyst poison for the catalyst layer existing in the extractive distillation column, thereby reducing the efficiency of the extractive distillation process, and the purification process Since the long-term operation of the nitrile is impossible, the content of the nitrile-based monomer in the upper discharge stream of the absorption tower 200 supplied to the refining unit 300 should be minimized.

As described above, by improving the removal rate of the nitrile-based monomer in the upper exhaust stream of the absorption tower 200 to 99.90% or more, the purification unit 300 through the recovery method of the conjugated diene-based monomer according to the present invention It can improve the efficiency of the internal purification process.

In addition, by improving the recovery rate of the conjugated diene-based monomer in the upper discharge stream of the absorption tower 200 to 99.5% or more, there is an effect of obtaining a high-purity conjugated diene-based monomer through the purification unit 300 . In addition, it is possible to minimize the content of the conjugated diene-based monomer discharged to the lower portion of the absorption tower 200, it is possible to reduce the load on the wastewater treatment facility by minimizing the content of the conjugated diene-based monomer in the final wastewater to be treated.

According to an embodiment of the present invention, the conjugated diene-based monomer purified from the purification unit 300 is re-supplied to the reactor 10 for polymerizing the nitrile-based monomer-conjugated diene-based monomer copolymer, and the raw material of the polymerization reaction can be reused as At this time, after re-supplying the purified conjugated diene-based monomer to the purified conjugated diene storage unit 310 , the purified conjugated diene storage unit 310 may supply it to the reactor 10 as necessary.

According to the present invention, there is provided an apparatus for recovering a conjugated diene-based monomer. As shown in FIG. 3 below, the apparatus for recovering the conjugated diene-based monomer may include a first condenser 100 , an absorption tower 200 , and a purification unit 300 .

As a specific example, the apparatus for recovering the conjugated diene-based monomer is supplied with a gaseous feed stream containing a nitrile-based monomer, a conjugated diene-based monomer, and water, a lower discharge stream containing a nitrile-based monomer and water, and a nitrile-based monomer and a first condenser 100 for discharging an overhead stream containing a conjugated diene-based monomer; The upper discharge stream of the first condenser 100 is supplied to the lower portion, the solvent is supplied to the upper portion, the lower discharge stream containing the nitrile-based monomer dissolved in the solvent, and the upper discharge containing the conjugated diene-based monomer an absorption tower 200 for discharging a stream; and a purification unit 300 receiving the upper discharge stream of the absorption tower 200 and purifying the conjugated diene-based monomer.

According to an embodiment of the present invention, the apparatus for recovering the conjugated diene-based monomer according to the present invention may be an apparatus for performing the process according to the method for recovering the conjugated diene-based monomer described above.

According to an embodiment of the present invention, the apparatus for recovering the conjugated diene-based monomer according to the present invention receives the upper discharge stream of the first condenser 100, and receives the lower discharge stream including the nitrile-based monomer and the conjugated diene-based monomer. It may further comprise two compressors (110, 120) for discharging the overhead effluent stream comprising the monomers. The two compressors 110 and 120 may include a first compressor 110 and a second compressor 120 .

According to an embodiment of the present invention, the apparatus for recovering the conjugated diene-based monomer according to the present invention may further include a second condenser 210 condensing the upper exhaust stream of the absorption tower 200 .

According to an embodiment of the present invention, the apparatus for recovering the conjugated diene-based monomer according to the present invention includes a crude conjugated diene storage unit 220 for storing the crude conjugated diene condensed from the second condenser 210 . may include more. In this way, the stored crude conjugated diene may be discharged from the crude conjugated diene storage unit 220 and supplied to the refining unit 300 as necessary, or a portion of the crude conjugated diene may be incinerated if necessary.

According to an embodiment of the present invention, the apparatus for recovering a conjugated diene-based monomer according to the present invention includes the first condenser 100 , the first compressor 110 , the second compressor 120 , the absorption tower 200 , and the second 2 A pipe connecting between the condenser 210, the crude conjugated diene storage unit 220 and the purification unit 300 may be provided, and the bottom discharge stream or the top discharge stream of each configuration can be easily converted into the configuration of a subsequent device. In order to supply, a pump (not shown) may be further provided on the pipe.

According to an embodiment of the present invention, in the method and recovery apparatus for recovering Gong&DEC-based monomers according to the present invention, if necessary, a distillation column (not shown), a condenser (not shown), a reboiler (not shown), a pump (not shown) ), a compressor (not shown), a mixer (not shown), and a separator (not shown) may be additionally installed.

As mentioned above, although the method and the recovery apparatus for the recovery of the conjugated diene-based monomer according to the present invention have been shown in the description and drawings, the description and drawings above describe and show only the essential components for understanding the present invention. And in addition to the process and apparatus shown in the drawings, processes and apparatus not separately described and not shown may be appropriately applied and used to implement the method and apparatus for recovering the conjugated diene-based monomer according to the present invention.

Hereinafter, the present invention will be described in more detail by way of Examples. However, the following examples are intended to illustrate the present invention, and it is apparent to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention, and the scope of the present invention is not limited thereto.

< Example >

Example One

As shown in the process flow diagram shown in FIG. 2 , the reactants are supplied to the reactor 10 at a flow rate of 17200 kg/h of butadiene, 6000 kg/h of acrylonitrile, and 32000 kg/h of water, and polymerization is completed in the presence of a catalyst, the polymerization is completed An aqueous polymer solution was obtained. At this time, the aqueous polymer solution contained water, an acrylonitrile-butadiene copolymer, unreacted monomers, and C4 impurities. In particular, 7% of the reacted monomers were unreacted, containing 1200 kg/h of butadiene, 420 kg/h of acrylonitrile, and 32000 kg/h of water.

Thereafter, the polymer aqueous solution is supplied to the stripper 20 and removed by vacuum heating to remove the unreacted monomers (butadiene and acrylonitrile), water and C4 impurities in a gaseous state to the upper part of the stripper 20 . and acrylonitrile-butadiene copolymer and water were discharged to the bottom.

Thereafter, the lower discharge stream of the stripper 20 was introduced into a commercialization process unit (not shown) to obtain Nitrile Butadiene Rubber Latex (NBL).

On the other hand, the gas stripped to the upper part of the stripper 20 was recovered as wastewater by condensing most of the acrylonitrile and water through the first condenser 100 . In addition, the non-condensed gas from the first condenser 100 passes through two successive sets of the first compressor 110 and the second compressor 120 to condense the remaining acrylonitrile and water to the lower part to recover wastewater. and, butadiene and C4 impurities were separated in a gaseous state. At this time, the operating pressure of the first compressor 110 was 0.3 kgf/cm ² (g), and the operating pressure of the second compressor 120 was 3 kgf/cm ² (g).

Thereafter, the upper discharge stream of the second compressor 120 discharged in the gaseous state is supplied to the lower portion of the absorption tower 200 , and water is supplied to the upper portion of the absorption tower 200 , and from the absorption tower 200 . A bottom draw stream comprising acrylonitrile and a top draw stream comprising butadiene and C4 by-products were drawn off.

Thereafter, the upper discharge stream of the absorption tower 200 is condensed by the second condenser 210 and supplied to the purification unit 300 to remove C4 impurities and then re-supplied to the reactor 10, a raw material for polymerization was reused as

In the process, the operating conditions of the absorption tower 200, the removal rate of acrylonitrile in the top discharge stream of the absorption tower 200, the recovery rate of butadiene, etc. are shown in Table 1 below.

Example 2

In Example 1, the process was simulated in the same manner as in Example 1, except that the operating pressure of the absorption tower 200 was operated at 0 kgf/cm ² (g) (atmospheric pressure).

Example 3

In Example 1, the process was simulated in the same manner as in Example 1, except that the operating pressure of the absorption tower 200 was operated at 5 kgf/cm ² (g).

Example 4

In Example 1, the process was simulated in the same manner as in Example 1, except that the temperature of water supplied to the upper part of the absorption tower 200 was supplied at 10 °C.

Example 5

In Example 1, the process was simulated in the same manner as in Example 1, except that the temperature of the water supplied to the upper part of the absorption tower 200 was supplied at 60 °C.

Example 6

In Example 1, the ratio of the supply flow rate of water supplied to the upper part of the absorption tower 200 to the supply flow rate of the upper discharge stream of the second compressor 120 supplied to the lower part of the absorption tower 200 A process was simulated in the same manner as in Example 1, except that 1 was supplied.

Example 7

In Example 1, the ratio of the supply flow rate of water supplied to the upper part of the absorption tower 200 to the supply flow rate of the upper discharge stream of the second compressor 120 supplied to the lower part of the absorption tower 200 A process was simulated in the same manner as in Example 1, except that No. 6 was supplied.

Example 8

In Example 1, except that the upper discharge stream of the first condenser 100 passed through the first compressor 110, not the two compressors, and then supplied to the absorption tower 200. The process was simulated in the same way as

comparative example One

As shown in the process flow diagram shown in FIG. 1, the reactants are supplied to the reactor 10 at a flow rate of 17200 kg/h of butadiene, 6000 kg/h of acrylonitrile, and 32000 kg/h of water, and polymerization is completed in the presence of a catalyst, polymerization is completed An aqueous polymer solution was obtained. At this time, the aqueous polymer solution contained water, an acrylonitrile-butadiene copolymer, unreacted monomers, and C4 impurities. In particular, 7% of the reacted monomers were unreacted, containing 1200 kg/h of butadiene, 420 kg/h of acrylonitrile, and 32000 kg/h of water.

Thereafter, the polymer aqueous solution is supplied to the stripper 20 and removed by vacuum heating to remove the unreacted monomers (butadiene and acrylonitrile), water and C4 impurities in a gaseous state to the upper part of the stripper 20 . and acrylonitrile-butadiene copolymer and water were discharged to the bottom.

Thereafter, the gas stripped to the upper part of the stripper 20 was recovered as wastewater by condensing most of the acrylonitrile and water through the first condenser 100 . In addition, the non-condensed gas from the first condenser 100 passes through the first compressor 110 to condense the remaining acrylonitrile and water to the lower part to recover wastewater, and to the upper part, butadiene and C4 impurities are in a gaseous state. discharged.

At this time, the operating pressure of the first compressor 110 was 0.3 kgf/cm ² (g), and the composition of the upper discharge stream of the first compressor 110 discharged in the gaseous state was 97 wt% butadiene, acrylo 2% by weight of nitrile and 1% by weight of water. Thereafter, the entire amount of the upper discharge stream of the first compressor 110 discharged in the gaseous state was incinerated through condensing and flaring.

division Example comparative example One 2 3 4 5 6 7 8 One *BD flow
(Kg/h) 1235 1235 1235 1235 1235 1235 1235 1271 1271 *AN before removal (Kg/h) 26.6 26.6 26.6 26.6 26.6 26.6 26.6 36.3 36.3 Absorption tower pressure (kgf/cm ² (g)) 3 0 5 3 3 3 3 0.3 - Absorption tower temperature (℃) 30 30 30 10 60 30 30 30 - *Absorbed water flow rate (Kg/h) 3705 3705 3705 3705 3705 1235 7410 3705 - * Absorption tower flow rate 3 3 3 3 3 One 6 3 *Residual AN (Kg/h) 0.02 6 0.003 0 1.3 4.6 0 5.0 36.3 *AN Removal Rate (%) 99.92 77.4 99.99 100.00 95.11 82.71 100.00 86.2 0 *BD in wastewater (Kg/h) 5 1.2 7.1 5.3 4.4 1.9 9 1.6 - *BD recovery (%) 99.6 99.9 99.4 99.6 99.6 99.8 99.3 99.9 0 *AN Removal Criteria ○ X ○ ○ X X ○ X X *Based on BD recovery ○ ○ X ○ ○ ○ X ○ -

* BD flow rate: the overhead effluent stream of the second compressor 120 (Examples 1 to 7), or the overhead effluent stream of the first compressor 110 (Example 8 and Comparative Example 1)

* AN before removal: the flow rate of acrylonitrile in the overhead effluent stream of the second compressor 120 (Examples 1-7), or the flow rate of acrylonitrile in the overhead effluent stream of the first compressor 110 (Examples 8 and Comparative Example 1)

* Absorption water flow rate: the flow rate of water (solvent) supplied to the upper part of the absorption tower

* Absorption tower flow rate: supply of the upper discharge stream of the second compressor 120 supplied to the lower part of the absorption tower 200 (the upper discharge stream of the first compressor 110 in Example 8 and Comparative Example 1) The ratio of the supply flow rate of water supplied to the upper part of the absorption tower 200 to the flow rate

* Residual AN: flow rate of acrylonitrile in the top discharge stream of the absorption tower 200 (the top discharge stream of the first compressor 110 in Comparative Example 1)

* AN removal rate: acryl contained in the upper discharge stream of the second compressor 120 supplied to the lower part of the absorption tower 200 (the upper discharge stream of the first compressor 110 in the case of Example 8 and Comparative Example 1) Removal rate of acrylonitrile in the overhead effluent stream of absorption tower 200 relative to ronitrile

* BD in wastewater: flow rate of butadiene in wastewater including the first condenser 100 bottoms discharge stream, the bottoms discharge stream of the two compressors 110 and 120 and the bottoms discharge stream of the absorption tower 200

* BD recovery rate: butadiene contained in the upper discharge stream of the second compressor 120 supplied to the lower part of the absorption tower 200 (the upper discharge stream of the first compressor 110 in Example 8 and Comparative Example 1) The recovery rate of butadiene in the top effluent stream of the absorption tower 200 for

* AN removal criteria: AN removal rate of 99.5% or more

* BD recovery criteria: BD recovery rate of 99.5% or more

Referring to Table 1, in Comparative Example 1 in which the absorption tower 200 was not introduced, the flow rate of residual acrylonitrile in the upper discharge stream of the first compressor 110 was 36.3 kg/h, and a large amount of acrylonitrile was included. can confirm. In this case, there is a problem in that acrylonitrile is dissolved and accumulated in the extraction solvent in the purification unit 300 performing extractive distillation, or acts as a catalyst poison, thereby lowering the purification efficiency and making it difficult to operate for a long period of time.

On the other hand, in the case of Example 1 in which the absorption tower 200 is introduced and the operating conditions (operating pressure, temperature of water supplied to the absorption tower 200, and the flow rate ratio of water) of the absorption tower 200 are set within an appropriate range, absorption It can be seen that the removal rate of acrylonitrile in the upper discharge stream of the tower 200 was excellent at 99.92%, and the recovery rate of butadiene was excellent at 99.6%.

On the other hand, even if the absorption tower 200 is introduced, in the case of the remaining embodiments in which the operating conditions of the absorption tower 200 are out of the appropriate range, the removal rate of acrylonitrile in the upper exhaust stream of the absorption tower 200 is lowered, so that butadiene A large amount of acrylonitrile was dissolved and accumulated in the extraction solvent in the purification process (refining unit 300) for In addition, there was a problem in that the recovery rate of butadiene was lowered, so that the flow rate of butadiene discharged to wastewater was increased. In addition, in the case of Example 4, by setting the temperature of the water supplied to the absorption tower 200 to 20 ℃ or less, an additional solvent cooling device was required, and there was a problem in that the energy required for cooling was unnecessarily consumed.

10: reactor
20: Remover
100: first condenser
110: first compressor
120: second compressor
200: absorption tower
210: second condenser
220: crude (crude) conjugated diene storage unit
300: refining unit
310: purified conjugated diene storage unit

Claims (12)

A gaseous feed stream containing a nitrile-based monomer, a conjugated diene-based monomer and water is supplied to a first condenser, a lower discharge stream containing a nitrile-based monomer and water, and an upper portion containing a nitrile-based monomer and a conjugated diene-based monomer separating the effluent stream (S10);
supplying the upper discharge stream of the first condenser to the lower portion of the absorption tower, and supplying the solvent to the upper portion of the absorption tower (S20);
Discharging the bottom discharge stream containing the nitrile-based monomer dissolved in the solvent from the absorption tower, and supplying the top discharge stream containing the conjugated diene-based monomer to the purification unit (S30) of the conjugated diene-based monomer recovery method. According to claim 1,
The feed stream is a method for recovering a conjugated diene-based monomer that is discharged from a reactor for polymerizing the nitrile-based monomer and the conjugated diene-based monomer. 3. The method of claim 2,
The feed stream is produced after recovering the nitrile-based monomer-conjugated diene-based monomer copolymer from the exhaust stream of the reactor including a nitrile-based monomer, a conjugated diene-based monomer, water, and a nitrile-based monomer-conjugated diene-based monomer copolymer. A method for recovering a conjugated diene-based monomer. According to claim 1,
A method for recovering a conjugated diene-based monomer by passing the upper discharge stream of the first condenser through two successive compressors and then supplying it to the lower part of the absorption tower. According to claim 1,
The method for recovering a conjugated diene-based monomer wherein the solvent is water. According to claim 1,
The supply temperature of the solvent is 20 to 50 ℃ recovery method of the conjugated diene-based monomer. According to claim 1,
The ratio of the supply flow rate of the solvent supplied to the upper portion of the absorption tower to the supply flow rate of the upper discharge stream of the first condenser supplied to the lower portion of the absorption tower is 2 to 5. Method of recovering a conjugated diene-based monomer. According to claim 1,
The operating pressure of the absorption tower is 1 to 4 kgf/cm ² (g) A method for recovering a conjugated diene-based monomer. According to claim 1,
A method for recovering a conjugated diene-based monomer to purify the conjugated diene-based monomer by removing C4 impurities from the purification unit. According to claim 1,
The purification unit is a method for recovering a conjugated diene-based monomer to purify the conjugated diene-based monomer through extractive distillation. 3. The method of claim 2,
A method for recovering a conjugated diene-based monomer by re-supplying the purified conjugated diene-based monomer from the purification unit to the reactor. A gaseous feed stream comprising nitrile monomers, conjugated diene monomers and water is supplied, and a bottom draw stream comprising nitrile monomers and water and a top draw stream comprising nitrile monomers and conjugated diene monomers are discharged a first condenser to
The upper discharge stream of the first condenser is supplied to the lower portion, the solvent is supplied to the upper portion, and the lower discharge stream containing the nitrile-based monomer dissolved in the solvent and the upper discharge stream containing the conjugated diene-based monomer are discharged absorption towers; and
A device for recovering a conjugated diene-based monomer comprising a purification unit receiving the upper discharge stream of the absorption tower and purifying the conjugated diene-based monomer.

Images