KR20220019991A - Method for preparing polymer - Google Patents

Abstract

The present invention relates to a preparation method of a polymer. More specifically, the present invention provides a preparation method of polymer which comprises: a step of supplying a feed stream comprising a reaction product and water to a first stripper, separating a solvent and an unreacted monomer from an upper part discharge stream, and supplying a lower part discharge stream to a second stripper; a step of supplying the upper part discharge stream of the second stripper to the first stripper and supplying the lower part discharge stream to a third stripper; and a step of supplying the upper part discharge stream of the third stripper to either the first stripper or the second stripper and separating a polymer from the lower part discharge stream. The preparation method of polymer satisfies mathematical equation 1 to 3 (refer to the specification). Mathematical equation 1 is T2 - T1 >= 10℃; mathematical equation 2 is T2 - T3 >= 5℃; and mathematical equation 3 is 102 ℃ >= T3 >= 93℃.

Description

Polymer manufacturing method {METHOD FOR PREPARING POLYMER}

The present invention relates to a method for producing a polymer, and more particularly, to a method for preparing a reaction product including a polymer and effectively separating and recovering unreacted monomers, solvents and polymers from the reaction product.

Rubber is one of the most useful materials today, and has elasticity. However, natural rubber produced from rubber trees is limited in production, so synthetic rubber to replace it is used in various fields. Synthetic rubber refers to a polymer material with the same or similar physical properties as natural rubber. Synthetic rubber includes butadiene rubber, styrene-butadiene rubber, acrylonitrile butadiene rubber, butyl rubber, and the like.

Methods such as suspension polymerization, emulsion polymerization, superficial polymerization, and solution polymerization are used for the production of the synthetic rubber. However, polymerization methods for producing synthetic rubber each have the following problems.

For example, when prepared by bulk polymerization, the viscosity of the reactant rapidly increases as the reaction proceeds, causing an increase in mechanical load, and furthermore, it is difficult to control the reaction temperature during polymerization, so commercial mass production is difficult. There is this.

Further, in the case of suspension polymerization, an initiator (catalyst) is dissolved in a monomer, the monomer is dispersed in water, and then a dispersant is incorporated to stabilize the suspension formed. In all suspension polymerization methods, a surfactant is used to disperse the monomer particles so that the polymer does not fuse and agglomerate during the reaction, and various dispersants such as water-insoluble particulate inorganic materials and organic materials are used depending on the monomer to be polymerized. It has the disadvantage of being lowered.

Therefore, in order to mass-produce synthetic rubber, a solution polymerization method or an emulsion polymerization method using a continuous polymerization reactor is mainly used.

As such, in order to recover unreacted monomers and solvents in the reaction product in the process of producing synthetic rubber through a continuous solution polymerization reaction, a steam stripping method using two strippers has been devised. At this time, since most of the stripping function in the first stripper is operated at high temperature and high pressure, there is a problem in that the loss of water that is evaporated to the upper part together with the solvent and unreacted monomer and discharged increases.

In addition, the stream separated and discharged through the steam stripping process is subjected to a dehydration step because it contains water along with the polymer. At this time, the content of unreacted monomers and solvents in the stream discharged after the steam stripping process is reduced In the dehydration step, there is a problem in that a large amount of unreacted monomers and solvents are discharged together with evaporated water, causing health and environmental toxicity problems of workers.

US 4408039 A

An object to be solved in the present invention is to provide a method of effectively removing a solvent and unreacted monomers and preparing a high-purity polymer in order to solve the problems mentioned in the technology that is the background of the present invention.

According to an embodiment of the present invention for solving the above problems, the present invention supplies a feed stream comprising a reaction product and water to a first stripper, separates the solvent and unreacted monomers from the upper discharge stream, and lowers the feeding the effluent stream to a second stripper; feeding the second stripper overhead effluent stream to a first stripper and feeding the bottoms effluent stream to a third stripper; and supplying the third stripper overhead effluent stream to the first stripper or the second stripper, and separating the polymer from the bottom effluent stream, wherein the following Equations 1 to 3 are satisfied. to provide.

[Equation 1]

T2 - T1 ≥ 10℃

[Equation 2]

T2 - T3 ≥ 5℃

[Equation 3]

102 ℃ ≥ T3 ≥ 93 ℃

In Equations 1 to 3, T1 is the operating temperature of the first stripper, T2 is the operating temperature of the second stripper, T3 is the operating temperature of the third stripper.

According to the method for preparing a polymer of the present invention, a reaction product including a polymer can be prepared, and unreacted monomers, a solvent, and a polymer can be effectively separated and recovered from the reaction product.

In addition, by operating by controlling the temperature and pressure of the first stripper, the second stripper and the third stripper in the method according to the present invention, the amount of water discharged by evaporation to the upper part with the solvent and unreacted monomer in the upper part of the first stripper The working environment was improved by reducing the amount of lost steam and the amount of unreacted monomers and solvents discharged together with the steam from the dehydration step, which is a subsequent process.

1 and 2 are process flow diagrams of a polymer manufacturing method according to an embodiment of the present invention, respectively.
3 is a process flow diagram of a method for preparing a polymer according to a comparative example.

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 '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.

In the present invention, the term 'crumb' refers to a polymer in the form of droplets, which is generated through a steam stripping process by supplying a reaction product to a stripper, and is removed by volatilizing unreacted monomers and solvents with steam (water vapor). can do.

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

According to the present invention, a method for preparing a polymer is provided. In the method for preparing the polymer, a feed stream comprising a reaction product and water is supplied to the first stripper 100 , the solvent and unreacted monomers are separated from the top effluent stream, and the bottom effluent stream is fed to the second stripper 200 . supplying; Supplying the second stripper 200 top effluent stream to the first stripper 100, the bottom effluent stream is supplied to the third stripper 300; and feeding the third stripper 300 overhead effluent stream to the first stripper 100 or the second stripper 200, and separating the polymer from the bottom effluent stream.

According to an embodiment of the present invention, the reaction product is produced by a polymerization reaction by supplying a monomer stream and a solvent stream to a reactor, and the reaction product may include a polymer, an unreacted monomer and a solvent. In this case, the polymer may be a synthetic rubber.

For example, the reaction product is produced by a polymerization reaction by supplying a solvent stream, a stream containing an aromatic vinylic monomer, and a stream containing a conjugated diene-based monomer to a reactor, and an aromatic vinyl-based monomer-derived unit and a conjugated diene-based unit. It may include a copolymer including a monomer-derived unit, an unreacted aromatic vinyl-based monomer, an unreacted conjugated diene-based monomer, and a solvent.

The polymer is not particularly limited as long as it includes an aromatic vinyl-based monomer-derived unit and a conjugated diene-based monomer-derived unit. For example, the polymer may be at least one selected from the group consisting of Styrene-Butadiene Rubber (SBR) and Solution Styrene-Butadiene Rubber (SSBR).

The conjugated diene-based monomer is, for example, 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, piperylene, 3-butyl-1,3-octadiene, isoprene, 2-phenyl-1, It may include one or more selected from the group consisting of 3-butadiene and 2-halo-1,3-butadiene (halo means a halogen atom). More specifically, in the present invention, the conjugated diene-based monomer may include 1,3-butadiene.

In addition, the aromatic vinyl-based monomer is, for example, styrene, α-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, 1-vinylnaphthalene, 4-cyclohexylstyrene, 4-(p- It may include at least one selected from the group consisting of methylphenyl)styrene and 1-vinyl-5-hexylnaphthalene. More specifically, in the present invention, the aromatic vinyl-based monomer may include styrene.

In addition, the solvent may include a hydrocarbon-based solvent. For example, the hydrocarbon-based solvent may include an aliphatic hydrocarbon-based solvent and an alicyclic hydrocarbon, and the aliphatic hydrocarbon-based solvent is one selected from the group consisting of butane, pentane, hexane, isopentane, heptane, octane and isooctane. The above may be included, and the alicyclic hydrocarbon-based solvent may include at least one selected from the group consisting of cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, and ethylcyclohexane. More specifically, in the present invention, the solvent may include n-hexane.

The at least one synthetic rubber selected from the group consisting of Styrene-Butadiene Rubber (SBR) and Solution Styrene-Butadiene Rubber (SSBR) is prepared by solution polymerization or emulsion polymerization. (Emulsion Polymerization) can be produced by continuous polymerization.

As such, the reaction product generated in the process of producing a polymer through a continuous solution polymerization reaction contains a solvent and an unreacted monomer. In the present invention, the unreacted monomer and the solvent and the polymer are effectively separated and recovered from the reaction product. , at the same time, to provide a way to improve the working environment.

According to an embodiment of the present invention, a feed stream comprising the reaction product and water is supplied to the first stripper 100, the solvent and unreacted monomers are separated from the top discharge stream, and the bottom discharge stream is the second stripper. (200) can be supplied.

Specifically, by mixing the reaction product with water, supplying a feed stream in which the reaction product and water are mixed to the first stripper 100, and heating using steam, unreacted monomers and solvents from the feed stream It can be evaporated with water and discharged to the top.

The flow ratio of the reaction product and water in the feed stream may be 1:1 to 1:3, 1:1.5 to 1:3, or 1:1.5 to 1:2.5. By mixing the reaction product and water within the above range, it is possible to control the content ratio of the polymer to the total content of the polymer and water in the feed stream to be 5 wt% to 13 wt% or 7 wt% to 9 wt%. In this case, the size of the crumbs can be adjusted by preventing the crumbs from aggregating through dispersion between the crumbs in the feed stream, and through this, the effect of allowing the unreacted monomers and solvents contained in the feed stream to be easily evaporated there is.

The temperature of the water mixed with the reaction product may be 85 °C to 120 °C, 95 °C to 120 °C, or 95 °C to 105 °C. By mixing water having a temperature within the above range with the reaction product and supplying it to the first stripper 100, by controlling the size of the crumb to 0.1 cm to 5 cm or 0.3 cm to 3 cm, unreacted monomers and solvents are easily removed To be evaporated, there is an effect of minimizing the loss of the polymer in the dehydration process to be described later.

According to an embodiment of the present invention, the first stripper 100 may have an operating temperature and operating pressure controlled in order to effectively separate unreacted monomers and solvents from the feed stream. For example, the operating temperature of the first stripper 100 may be 80 ℃ to 110 ℃, 85 ℃ to 100 ℃ or 90 ℃ to 98 ℃. In addition, the operating pressure of the first stripper 100 may be 0.5 KG to 1 KG, 0.6 KG to 0.9 KG, or 0.7 KG to 0.8 KG. The first stripper 100 could be controlled to a relatively low temperature due to the operating temperature and operating pressure control of the second stripper 200 and the third stripper 300 to be described later, and through this, in the first stripper 100 It is possible to reduce the amount of water lost by evaporation to the top together with the solvent and unreacted monomers. For example, the ratio of the content of water to the content of the solvent in the first stripper 100 upper discharge stream may be 0.1 to 0.2, 0.3 to 0.2, or 0.5 to 0.2.

According to an embodiment of the present invention, the first stripper 100 lower discharge stream may be supplied to the second stripper 200 as a stream having a high content of the polymer from which unreacted monomers and solvents are removed. The second stripper 200 can be supplied to the first stripper 100 by receiving the first stripper 100 lower discharge stream, removing the unreacted monomer and solvent as much as possible from the upper discharge stream, and supplying it to the first stripper 100, the content of the polymer is more The high bottoms effluent stream may be fed to a third stripper 300 .

The second stripper 200 upper discharge stream is supplied to the lower portion of the first stripper 100, it is possible to separate the unreacted monomer and solvent again in the first stripper 100, the first stripper 100 energy can be transferred.

In the second stripper 200, the operating temperature and operating pressure may be controlled in order to maximally separate unreacted monomers and solvents from the first stripper 100 lower discharge stream. For example, the operating temperature of the second stripper 200 may be 105 °C to 130 °C, 105 °C to 125 °C or 105 °C to 110 °C. In addition, the operating pressure of the second stripper 200 may be 0 KG to 0.5 KG, 0.1 KG to 0.5 KG or 0.2 KG to 0.4 KG. By controlling the operating temperature and operating pressure of the second stripper 200 within the above ranges, the third stripper 300 to be described below by maximally removing unreacted monomers and solvents in the first stripper 100 lower discharge stream to be described later. It is possible to minimize the content of unreacted monomers and solvents inside, and to operate the first stripper 100 at a relatively low temperature.

The first stripper 100 and the second stripper 200 may be operated while satisfying Equation 1 below.

[Equation 1]

T2 - T1 ≥ 10℃

In Equation 1, T1 is the operating temperature of the first stripper 100, T2 is the operating temperature of the second stripper (200). Specifically, the operating temperature of the second stripper 200 may be operated more than 10 ℃, 10 ℃ to 20 ℃ or 10 ℃ to 15 ℃ higher than the operating temperature of the first stripper 100. By driving the first stripper 100 and the second stripper 200 while satisfying Equation 1, The temperature of the first stripper 100 is operated at a low temperature to reduce the loss of water that is evaporated to the upper part together with the solvent and unreacted monomer, and at the same time, the temperature of the second stripper 200 is operated at a high temperature to be described later by the third The content of unreacted monomer and solvent in the stripper bottoms effluent stream can be minimized.

According to an embodiment of the present invention, the second stripper 200 lower discharge stream may be supplied to the third stripper 300 as a stream with a higher polymer content by removing the unreacted monomers and solvents as much as possible. The third stripper 300 receives the second stripper 200 lower discharge stream, and the unreacted monomer and solvent remaining from the upper discharge stream can be supplied to the first stripper 100 or the second stripper 200 and , the bottoms effluent stream comprising water and a high content of polymer can be discharged as polymer crumb. At this time, the content of the unreacted monomer and solvent in the third stripper 300 lower discharge stream may be 1 wt% or less, 0.01 wt% to 1 wt%, or 0.1 wt% to 1 wt%.

The third stripper 300 top discharge stream is supplied to the lower portion of the first stripper 100 or the second stripper 200, and can again separate unreacted monomers and solvents, the first stripper 100 or Energy may be transferred to the second stripper 200 .

The third stripper 300 separates the unreacted monomers and solvent remaining from the second stripper 200 lower discharge stream, and uses the evaporated water (superheated steam) contained in the upper discharge stream to the first stripper (100) or in order to supply energy to the second stripper 200, it may be operated while satisfying Equations 2 and 3 below.

[Equation 2]

T2 - T3 ≥ 5℃

[Equation 3]

102 ℃ ≥ T3 ≥ 93 ℃

In Equations 2 and 3, T2 is the operating temperature of the second stripper 200 , and T3 is the operating temperature of the third stripper 300 .

Specifically, the operating temperature of the third stripper 300 may be operated at least 5 ℃, 5 ℃ to 15 ℃ or 5 ℃ to 10 ℃ lower than the second stripper 200 operating temperature. At the same time, the third stripper 300 may be operated at a temperature of 93 ℃ to 102 ℃, 93 ℃ to 100 ℃ or 95 ℃ to 100 ℃. By driving the third stripper 300 while satisfying Equation 2 and Equation 3, Due to the temperature difference between the second stripper 200 and the third stripper 300, the amount of steam generated by the third stripper 300 is increased to effectively evaporate the residual unreacted monomers and solvents in the third stripper 300, thereby evaporating in the dehydration step. The content of unreacted monomers and solvents discharged together with water is minimized, which can improve the working environment. In addition, by driving the temperature of the third stripper 300 low to near 100 ° C., the third stripper 300 lower discharge stream is transferred to the dehydration step at a temperature of about 100 ° C. and a pressure of 0 KG (atmospheric pressure) when transferring the temperature difference It is possible to reduce the amount of steam loss caused by the steam being discharged to the outside by minimizing the generation of steam. there is. In addition, this can improve the working environment of the operator.

In addition, the operating pressure of the third stripper 300 may be -0.5 KG to 0 KG, -0.4 KG to 0 KG, or -2.5 KG to 0 KG. By operating the operating pressure of the third stripper 300 in the above range, for example, 0 KG or less, it is possible to prevent steam generation in the dehydration step to be described later to improve the health and work environment of workers.

According to an embodiment of the present invention, the third stripper 300 bottoms discharge stream is discharged to contain water and a high content of polymer, further comprising the step of dewatering the third stripper 300 bottoms discharge stream can do. Specifically, the third stripper 300 bottom discharge stream is removed by evaporating water to water vapor through a dehydration step through heating, and a polymer of high purity can be obtained.

In the dehydration step, unreacted monomers and solvents remaining in the third stripper 300 bottom discharge stream, that is, volatile hydrocarbons may be discharged to the atmosphere together with evaporated water. In this case, there were problems of worker health and environmental toxicity. In contrast, in the present invention, by controlling the operating conditions of the first stripper 100 to the third stripper 300 to minimize the content of unreacted monomers and solvents in the third stripper 300 lower discharge stream, evaporation in the dehydration step The content of volatile hydrocarbons emitted along with the water used was minimized, and the working environment could be improved through this.

The dehydration step may be performed under a temperature of about 100 °C under a pressure condition of about 0 KG (normal pressure). At this time, due to the difference between the operating temperature (pressure) of the third stripper 300 and the temperature (pressure) of the dehydration step, steam is generated when the third stripper 300 lower discharge stream is transferred to the dehydration step, which is a downstream process, which is dehydrated. Steam is discharged to the outside in the step, resulting in loss of steam. In contrast, in the present invention, by operating the operating temperature of the third stripper 300 similarly to the temperature of the dehydration step, which is a downstream process, steam is generated due to the temperature difference between the temperature of the third stripper 300 and the dehydration step it can be prevented

According to an embodiment of the present invention, in order to separate the polymer through the steam stripping method in the first stripper 100 to the third stripper 300, and to recover unreacted monomers and solvents, the first stripper 100 ) Steam is supplied through the first line 110 connected to the lower portion, the steam is supplied through the second line 210 connected to the lower portion of the second stripper 200, and the third stripper 300 connected to the lower portion Steam is supplied through a third line 310, and steam is supplied through a fourth line 220 connected to the second stripper 200 upper discharge stream, and the third stripper 300 upper discharge stream and Steam may be supplied through the connected fifth line 320 .

Specifically, the steam supplied through the first line 110 to the third line 310 may be supplied as a heat source for heating the first stripper 100 to the third stripper 300, respectively.

In addition, the steam supplied to the fourth line 220 and the fifth line 320 heats the second stripper 200 upper discharge stream and the third stripper 300 upper discharge stream, respectively, to ensure flowability can be supplied for Specifically, the fourth line 220 may be connected to a pump installed in a line for supplying the second stripper 200 upper discharge stream to the lower portion of the first stripper 100, and the fourth line 220 is supplied through The second stripper 200 by using the steam to heat the upper discharge stream, it is possible to ensure the flowability to the first stripper (100). In addition, the fifth line 320 may be connected to a pump installed in a line supplying the third stripper 300 upper discharge stream to the lower portion of the first stripper 100 or the second stripper 200, the fifth line By using the steam supplied through 320, the third stripper 300 heating the upper discharge stream, it is possible to ensure the flowability to the first stripper 100 or the second stripper 200.

The amount of steam supplied through the first line 110 is 35% or less, 15% to 35%, or 20% to 27% of the total amount of steam supplied to the first line 110 to the fifth line 320 . It can be %. In addition, the amount of steam supplied to the second line 210 to the fifth line 320 is 65% or more, 65% to 65% of the total amount of steam supplied to the first line 110 to the fifth line 320 85% or 70% to 80%. In this way, the first stripper 100 by receiving energy from the second stripper 200 and the third stripper 300, the first stripper 100 through the first line 110, steam supplied to the lower part can reduce the amount of

According to an embodiment of the present invention, in the polymer manufacturing method, if necessary, equipment such as a separation column, a condenser, a reboiler, a pump, a compressor, a mixing device and a separation device may be additionally installed.

As mentioned above, although the method for producing a polymer according to the present invention has been shown in the description and drawings, the drawings and the description above describe and show only the essential components for understanding the present invention, and the process shown in the description and drawings and In addition to the apparatus, processes and apparatus not separately described and not shown may be appropriately applied and used for carrying out the polymer production method 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

Examples 1 to 3

With respect to the process flow diagram shown in FIG. 1, the process was simulated using Aspen Plus Simulator of Aspen Tech. In this case, a styrene monomer was used as the vinyl aromatic monomer, 1,3-butadiene was used as a conjugated diene-based monomer, and n-hexane was used as a solvent to prepare a reaction product.

The reaction product contains 6.7 ton/hr of styrene-butadiene copolymer, 37 ton/hr of hexane, and 0.1 ton/hr of unreacted monomer, and is prepared as a feed stream by mixing the reaction product and 90 ton/hr of water at 91° C. 1 was fed to the stripper (100).

In the first stripper 100, unreacted monomers and solvents were separated from the top discharge stream, and the bottom discharge stream was fed to the second stripper 200. At this time, steam at 245 ° C. was supplied through the first line 110 connected to the lower portion of the first stripper 100 .

The top discharge stream from the second stripper 200 is supplied to the bottom of the first stripper 100, and the bottom discharge stream is supplied to the third stripper 300. At this time, the second stripper 200, steam was supplied through the second line 210 connected to the lower portion of 245 ℃, the upper discharge stream connected to the pump installed in the line supplying the first stripper 100 to the lower part 4 Steam at 245° C. was supplied through line 220.

The third stripper 300 top discharge stream is supplied to the second stripper 200, and the bottom discharge stream is separated and subjected to a dehydration step at a pressure of about 0 KG (atmospheric pressure) and a temperature of 100 ° C. After that, the polymer is separated did At this time, steam of 245 ℃ was supplied through the third line 310 connected to the lower part of the third stripper 300, and the second stripper connected to the pump installed in the line for supplying the upper discharge stream to the lower part of the second stripper 200. Steam at 245° C. was supplied through line 320.

In addition, the operating temperature of the first stripper 100 (T1), the operating temperature of the second stripper 200 (T2), the operating temperature of the third stripper 300 (T3), Equation 1 (ΔT1), mathematical Equation 2 (ΔT2), the amount of steam supplied through the first line 110 (STM1), the amount of steam supplied through the second line 210 to the fifth line 320 (STM2-5), The content ratio of water to the content of solvent in the first stripper 100 overhead (WT/HX), the second stripper 200, the amount of evaporated water (superheated steam) in the overhead output stream (V2), the third stripper ( 300) The amount of evaporated water (V3) in the top discharge stream, the amount of steam lost from the dehydration step, and the amount of unreacted monomer and solvent (HC) in the third stripper 300 bottom discharge stream are measured and shown in Table 1 below. it was

Example 4

In Example 1, it was carried out in the same manner as in Example 1, except that the upper discharge stream of the third stripper 300 was supplied to the first stripper 100 as shown in FIG. 2 below.

In addition, the operating temperature (T1) and operating pressure (P1) of the first stripper 100, the operating temperature (T2) and operating pressure (P2) of the second stripper 200, the operating temperature of the third stripper (300) ( T3) and the operating pressure P3, Equation 1 (ΔT1), Equation 2 (ΔT2), the amount of steam supplied through the first line 110 (STM1), the second line 210 to the second 5 The amount of steam supplied through line 320 (STM2-5), the ratio of the content of water to the content of the solvent in the first stripper 100 top discharge stream (WT/HX), the second stripper 200 top discharge stream The amount of evaporated water (superheated steam) in (V2), the amount of evaporated water in the third stripper 300 overhead effluent stream (V3), the amount of steam lost from the dewatering step and in the third stripper 300 bottom effluent stream The amounts (HC) of unreacted monomers and solvents were measured and shown in Table 1 below.

Example 1 Example 2 Example 3 Example 4 stripper T1(℃) 95 95 95 95 P1(KG) 0.75 0.75 0.75 0.75 T2(℃) 105 110 105 105 P2(KG) 0.25 0.45 0.25 0.25 T3(℃) 100 100 95 100 P3(KG) 0 0 -0.15 0 △T1(℃) 10 15 10 10 △T2(℃) 5 10 10 5 WT/HX 0.175 0.175 0.175 0.175 steam supply STM1 ton/hr 3.5 2.7 3.2 1.4 wt% 27.1 20.9 26.4 13.2 STM2~5 ton/hr 9.4 10.2 8.9 11.5 wt% 72.9 79.1 73.6 89.1 total 12.9 12.9 12.1 12.9 Superheated steam (ton/hr) V2 6.4 7 6.4 4.2 V3 3.3 3.7 4.1 1.8 total 9.7 10.7 10.5 6.0 Steam loss (ton/hr) 0 0 0 0 HC (wt%) 0.83 0.75 0.75 0.91

comparative example

Comparative Example 1

With respect to the process flow diagram shown in FIG. 3, the process was simulated using Aspen Plus Simulator of Aspen Tech. In this case, a styrene monomer was used as the vinyl aromatic monomer, 1,3-butadiene was used as a conjugated diene-based monomer, and n-hexane was used as a solvent to prepare a reaction product.

The reaction product includes 6.7 ton/hr of styrene-butadiene copolymer, 37 ton/hr of hexane, and 0.1 ton/hr of unreacted monomer, and is prepared as a feed stream by mixing the reaction product and 90 ton/hr of water at 91° C. 1 was fed to the stripper (100).

In the first stripper 100, unreacted monomers and solvents were separated from the top discharge stream, and the bottom discharge stream was fed to the second stripper 200. At this time, steam at 245 ° C. was supplied through the first line 110 connected to the lower portion of the first stripper 100 .

The upper discharge stream from the second stripper 200 is supplied to the lower portion of the first stripper 100, and the lower discharge stream is separated and subjected to a dehydration step at a temperature of about 0 KG (atmospheric pressure) and 100 ° C. After that, the polymer is separated did At this time, the second stripper 200, steam at 245 ℃ was supplied through the second line 210 connected to the lower portion, and the first stripper 100 connected to the pump installed in the line supplying the upper discharge stream to the lower portion. Steam at 245° C. was supplied through line 220.

In addition, the operating temperature (T1) and operating pressure (P1) of the first stripper 100, the operating temperature (T2) and operating pressure (P2) of the second stripper 200, Equation 1 (ΔT1), the first The amount of steam supplied through the line 110 (STM1), the amount of steam supplied through the second line 210 and the fourth line 220 (STM2-5), the first stripper 100 top discharge stream The content ratio of water to the content of solvent (WT/HX), the amount of evaporated water (superheated steam) in the outlet stream above the second stripper 200 (V2), the amount of steam lost from the dehydration step and the second stripper 200 ) The amounts (HC) of unreacted monomers and solvents in the bottom discharge stream were measured and shown in Table 2 below.

Comparative Examples 2 to 4

In Example 1, the same method as in Example 1, except that the operating conditions of the first stripper 100, the second stripper 200 and the third stripper 300 were controlled as shown in Table 1 below. was performed with

In addition, the operating temperature (T1) and operating pressure (P1) of the first stripper 100, the operating temperature (T2) and operating pressure (P2) of the second stripper 200, the operating temperature of the third stripper (300) ( T3) and the operating pressure P3, Equation 1 (ΔT1), Equation 2 (ΔT2), the amount of steam supplied through the first line 110 (STM1), the second line 210 to the second 5 The amount of steam supplied through line 320 (STM2 to 5), the ratio of the content of water to the content of the solvent in the first stripper 100 top discharge stream (WT/HX), the second stripper 200 top discharge stream The amount of evaporated water (superheated steam) in (V2), the amount of evaporated water (V3) in the third stripper 300 overhead effluent stream, the amount of steam lost from the dewatering step and in the third stripper 300 bottom effluent stream The amounts (HC) of unreacted monomers and solvents were measured and shown in Table 2 below.

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 stripper T1(℃) 95 95 95 100 P1(KG) 0.75 0.75 0.30 0.85 T2(℃) 105 105 105 105 P2(KG) 0.25 0.25 0.25 0.25 T3(℃) - 103 90 100 P3(KG) - 0.15 -0.30 0 △T1(℃) 10 10 10 5 △T2(℃) - 2 15 5 WT/HX 0.175 0.175 0.378 0.25 steam supply STM1 ton/hr 8.4 3.3 1.9 3.0 wt% 54.2 22.6 11.3 20.5 STM2~5 ton/hr 7.1 11.3 15.2 12.9 wt% 45.8 77.4 88.9 88.4 total 15.5 14.6 17.1 15.9 Superheated steam (ton/hr) V2 1.5 6.9 11.2 8.9 V3 - 3.2 5.8 2.7 total 1.5 10.1 17.0 11.6 Steam loss (ton/hr) 1.4 1.1 0 0 HC (wt%) 1.8 0.8 0.67 0.65

Referring to Table 1 and Table 2, by controlling the operating conditions of the first stripper 100 to the third stripper 300 through the polymer manufacturing method according to the present invention, the polymer is separated from the reaction product, and the unreacted monomer And when the solvent is separated and recovered, the total amount of steam used in the process is reduced because the amount of steam additionally required in the first stripper 100 is reduced, there is no loss of steam, and the third stripper 300 is transferred to the dehydration step. It was confirmed that the amount of unreacted monomer and solvent remaining in the bottom discharge stream was very small.

In comparison, in the case of Comparative Example 1 in which the polymer, unreacted monomers and solvents were separated using the two strippers, the amount of steam additionally required in the first stripper 100 was increased, and due to this, used in the process It can be seen that the total amount of steam used has increased. In addition, the amount of steam loss increased due to the difference between the operating temperature of the second stripper 200 and the temperature difference of the dehydration step, and the amount of superheated steam of the second stripper 200 was small as 1.5 ton/hr, so unreacted monomers and solvents were not evaporated well. Therefore, it was confirmed that the content of unreacted monomers and solvents in the second stripper 200 lower discharge stream transferred to the dehydration step increased.

In addition, using three strippers as in the present invention, exceeding the upper limit of the temperature range of the third stripper 300, the temperature difference between the second stripper 200 and the third stripper 300 (Equation 2) In the case of the unsatisfactory Comparative Example 2, it was confirmed that the steam was discharged as much as the difference between the operating temperature and pressure of the third stripper 300 and the temperature and pressure of the dehydration step, thereby increasing the amount of steam loss.

In addition, in the case of Comparative Example 3, which uses three strippers as in the present invention, but does not satisfy the lower limit of the temperature range of the third stripper 300, the third stripper 300 due to the low temperature and low pressure As the amount of steam (STM4) supplied to line 4 increases, it can be seen that the total steam supply amount is increased. In addition, due to the increase in the amount of superheated steam, the pressure of the first stripper 100 is lowered, there is a problem in that the content of water evaporated and discharged in the first stripper 100 upper discharge stream is high.

In addition, in the case of Comparative Example 4 that does not satisfy the temperature difference (Equation 1) of the first stripper 100 and the second stripper 200 using three strippers as in the present invention, the first stripper 100 Since the amount of steam additionally required to increase the temperature of In addition, due to the high pressure and temperature of the first stripper 100, there is a problem in that the content of water evaporated and discharged in the first stripper 100 upper discharge stream is high.

100: first stripper
110: first line
200: second stripper
210: second line
220: fourth line
300: third stripper
310: third line
320: fifth line

Claims (13)

feeding a feed stream comprising the reaction product and water to a first stripper, separating solvent and unreacted monomers from an overheads effluent stream, and feeding a bottoms effluent stream to a second stripper;
feeding the second stripper overhead effluent stream to a first stripper and feeding the bottoms effluent stream to a third stripper; and
feeding the third stripper overhead effluent stream to either a first stripper or a second stripper and separating the polymer from the bottoms effluent stream;
A method for preparing a polymer that satisfies the following Equations 1 to 3:
[Equation 1]
T2 - T1 ≥ 10℃
[Equation 2]
T2 - T3 ≥ 5℃
[Equation 3]
102 ℃ ≥ T3 ≥ 93 ℃
In Equations 1 to 3, T1 is the operating temperature of the first stripper, T2 is the operating temperature of the second stripper, T3 is the operating temperature of the third stripper. According to claim 1,
The reaction product is a polymerization reaction produced by supplying a monomer stream and a solvent stream to a reactor,
The reaction product is a method for producing a polymer comprising a polymer, an unreacted monomer and a solvent. According to claim 1,
The polymer is synthetic rubber. According to claim 1,
A method for producing a polymer wherein a flow ratio of the reaction product and water is 1:1 to 1:3. According to claim 1,
The operating temperature of the second stripper is a polymer manufacturing method that is 10 ℃ to 15 ℃ higher than the operating temperature of the first stripper. According to claim 1,
The operating temperature of the third stripper is 5 ℃ to 10 ℃ lower than the operating temperature of the second stripper polymer manufacturing method. According to claim 1,
The operating temperature of the third stripper is a polymer manufacturing method of 95 ℃ to 100 ℃. According to claim 1,
A method for producing a polymer wherein the ratio of the content of water to the content of the solvent in the first stripper overhead discharge stream is 0.1 to 0.2. According to claim 1,
The operating pressure of the first stripper is 0.5 KG to 1 KG,
The operating pressure of the second stripper is 0 KG to 0.5 KG,
The operating pressure of the third stripper is -0.5 KG to 0 KG of the polymer manufacturing method. According to claim 1,
Steam is supplied through a first line connected to the lower portion of the first stripper,
Steam is supplied through a second line connected to the lower portion of the second stripper,
Steam is supplied through a third line connected to the lower part of the third stripper,
Steam is supplied through a fourth line connected to the second stripper overhead effluent stream,
wherein steam is fed through a fifth line connected to the effluent stream above the third stripper. 11. The method of claim 10,
The amount of steam supplied through the first line is 35% or less of the total amount of steam supplied to the first line to the fifth line. According to claim 1,
The content of unreacted monomers and solvents contained in the third stripper bottom outlet stream is 1 wt% or less. According to claim 1,
and dewatering the third stripper bottoms effluent stream.

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