WO2021033971A1 - Oligomer preparation method and oligomer preparation device - Google Patents

Abstract

The present invention relates to an oligomer preparation method and provides an oligomer preparation method and preparation device, the oligomer preparation method comprising the steps of: carrying out an oligomerization reaction by supplying a reactor with a feed stream containing a monomer; supplying a first discharge stream of the reactor to a first separator, and supplying a second discharge stream of the reactor to a second separator; recovering the monomer by an upper discharge stream of the second separator, and supplying a lower discharge stream thereof to a third separator; and supplying an upper discharge stream of the third separator to the second separator.

Description

Oligomer manufacturing method and oligomer manufacturing apparatus

Mutual citation with related applications

This application claims the benefit of priority based on Korean Patent Application No. 10-2019-0102511 filed on August 21, 2019 and Korean Patent Application No. 10-2020-0094665 filed on July 29, 2020. All contents disclosed in the literature are included as part of this specification.

Technical field

The present invention relates to an oligomer manufacturing method and an oligomer manufacturing apparatus, and more particularly, to an oligomer manufacturing method and an oligomer manufacturing apparatus for efficiently recycling the monomers recovered in the oligomer manufacturing process.

Alpha-olefin is an important material used in comonomers, detergents, lubricants, plasticizers, etc., and is widely used commercially.In particular, 1-hexene and 1-octene control the density of polyethylene in the production of linear low-density polyethylene (LLDPE). It is widely used as a comonomer for regulation.

Alpha olefins such as 1-hexene and 1-octene are typically produced through an oligomerization reaction of ethylene. The ethylene oligomerization reaction is carried out by an oligomerization reaction (trimerization reaction or tetramerization reaction) of ethylene using ethylene as a reactant, and the product produced through the reaction contains the desired 1-hexene and 1-octene. It contains unreacted ethylene as well as multi-component hydrocarbon mixtures. The product is subjected to a separation process through a distillation column, and at this time, unreacted ethylene is recovered and reused for the ethylene oligomerization reaction.

In recovering the unreacted ethylene, a separation device such as a distillation column or a flash drum is used to reduce the amount of products or by-products such as solvents in the recovered unreacted ethylene stream. At this time, the difference in boiling point between the unreacted ethylene and the product is large, so that the difference in upper and lower temperatures of the separation device is also large. The upper and lower temperatures of the separating device are determined according to the pressure of the separating device. When the pressure of the separating device is high, the upper and lower temperatures are increased, and when the pressure of the separating device is low, the upper and lower temperatures are lowered. In the case of increasing the pressure of the separation device, if the pressure of the separation device is increased, the upper temperature of the separation device is increased to facilitate the recovery of unreacted ethylene, but the lower temperature of the separation device is also increased, so that hydrocarbons such as products and solvents are decomposed. And the reaction can be accelerated, there is a problem that the production yield of the product is lowered. On the other hand, if the pressure of the separation device is lowered, side reactions of hydrocarbons can be suppressed, but the upper temperature of the separation device is lowered, so that a low-temperature refrigerant is used to recover unreacted ethylene or a compressor with a high compression ratio is installed. An additional configuration such as, etc. is required, and in this case, there is a problem that the process cost increases.

As described above, the conventional method for recovering unreacted ethylene and reusing it for the oligomerization reaction has high investment costs, such as lowering the production yield of the product, using a refrigerant having a very low temperature, or installing a compressor having a high compression ratio, There is a problem with poor economics.

The problem to be solved in the present invention is to provide an oligomer manufacturing method and an oligomer manufacturing apparatus with reduced investment cost in order to solve the problems mentioned in the technology behind the present invention.

That is, in the present invention, in the oligomer manufacturing process, when unreacted ethylene is recovered and reused for the oligomerization reaction, there is no need to use a very low temperature refrigerant or install a compressor with a high compression ratio, thereby reducing investment cost and improving economic efficiency. It is an object of the present invention to provide an oligomer manufacturing method and an oligomer manufacturing apparatus capable of preventing a decrease in product yield.

According to an embodiment of the present invention for solving the above problems, the present invention comprises the steps of performing an oligomerization reaction by supplying a feed stream containing a monomer to a reactor; Supplying a first discharge stream of the reactor to a first separation device, and supplying a second discharge stream of the reactor to a second separation device; Recovering the monomer to the upper discharge stream of the second separation device, and feeding the lower discharge stream to a third separation device; And supplying the upper discharge stream of the third separation device to a second separation device.

In addition, the present invention is a reactor for oligomerizing a feed stream containing the supplied monomer, supplying a first discharge stream to a first separation device, and supplying a second discharge stream to a second separation device; A first separation device receiving the reactor first discharge stream; A second separation device for receiving the second discharge stream of the reactor, recovering the monomer as an upper discharge stream, and supplying the lower discharge stream to a third separation device; And a third separation device configured to receive the second separation device lower discharge stream and supply the upper discharge stream to the second separation device.

According to the oligomer manufacturing method and oligomer manufacturing apparatus of the present invention, in recovering the unreacted monomer, the second separation device is operated at high pressure, and the third separation device to which the lower discharge stream of the second separation device is connected is operated at low pressure. , By supplying the upper discharge stream of the third separation device to the second separation device to connect the second separation device and the third separation device, the lower stream of the second separation device has a boiling point higher than a monomer and a boiling point lower than an oligomer product. The by-product can be concentrated. Accordingly, by operating the second separation device at high pressure, the upper temperature is maintained at a high temperature and the lower temperature is lowered, thereby efficiently recovering the monomer and suppressing side reactions of hydrocarbons.

In addition, by removing concentrated by-products from the circulation flow of the second separation device and the third separation device, it is possible to reduce the loss of monomers.

1 is a process flow diagram according to a method for manufacturing an oligomer according to an embodiment of the present invention.

2 and 3 are process flow charts according to the oligomer manufacturing method according to the comparative example, respectively.

Terms or words used in the description and claims of the present invention should not be construed as being limited to their usual or dictionary meanings, and the inventors appropriately explain the concept of terms in order to explain their own invention in the best way. Based on the principle that it can be defined, it should be interpreted as a 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 the fluid itself and the flow of the fluid simultaneously flowing in a pipe connecting each device. In addition, the fluid may mean gas or liquid.

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

According to the present invention, a method for preparing an oligomer is provided. As the oligomer production method, the step of performing an oligomerization reaction by supplying a feed stream containing a monomer to a reactor; Supplying a first discharge stream of the reactor to a first separation device, and supplying a second discharge stream of the reactor to a second separation device; Recovering the monomer to the upper discharge stream of the second separation device, and feeding the lower discharge stream to a third separation device; And supplying the top discharge stream of the third separation device to a second separation device.

According to an embodiment of the present invention, in the step of performing an oligomerization reaction by supplying a feed stream containing a monomer to a reactor, a feed stream containing a monomer is supplied to the reactor, and the monomer is in a liquid phase at the bottom of the reactor. The oligomerization reaction of can be carried out. The oligomerization reaction may mean a reaction in which a monomer is micropolymerized. Depending on the number of monomers to be polymerized, they are called trimerization and tetramerization, and these are collectively referred to as multimerization.

According to an embodiment of the present invention, the monomer may be ethylene, and the oligomer may be an alpha olefin. Alpha olefin is an important material used for comonomers, detergents, lubricants, plasticizers, etc., and is widely used commercially.In particular, 1-hexene and 1-octene are balls for controlling the density of polyethylene in the manufacture of linear low-density polyethylene (LLDPE). It is widely used as a monomer. Alpha olefins such as 1-hexene and 1-octene may be prepared, for example, through a trimerization reaction or tetramerization reaction of ethylene.

According to an embodiment of the present invention, the step of the oligomerization reaction of the monomer may be carried out in a reactor suitable for a continuous process, preferably selected from the group consisting of a continuous stirred reactor (CSTR) and a plug flow reactor (PFR). It can be carried out under a reaction system comprising one or more reactors.

According to an embodiment of the present invention, the oligomerization reaction of the monomer is a homogeneous liquid phase reaction in the presence or absence of a solvent by applying a conventional contact technique with the reaction system, a form in which some or all of the catalyst system is not dissolved. It can be carried out as a phosphorus slurry reaction, a two-phase liquid/liquid reaction, or as a bulk or gaseous reaction in which the product acts as the main medium. Preferably, the step of the oligomerization reaction of the monomer may be performed as a homogeneous liquid phase reaction.

According to an embodiment of the present invention, the step of performing the oligomerization reaction may be performed at a temperature of 10°C to 180°C, 30°C to 150°C, or 50°C to 120°C . In addition, the step of performing the oligomerization reaction may be performed under a pressure of 15 bar to 100 bar, 20 bar to 80 bar, or 25 bar to 60 bar. When ethylene is oligomerized within the above temperature range and pressure range, selectivity for the desired alpha olefin can be excellent, the amount of by-products can be reduced, and the operational efficiency of the continuous process can be increased and cost can be reduced. have.

According to an embodiment of the present invention, the feed stream including the monomer may include a vapor phase monomer and a solvent.

The gaseous monomer contained in the feed stream may be supplied as a feed stream containing the monomer directly or after a storage step of the ethylene monomer separated in a Naphtha Cracking Center (NCC) process. In addition, the gaseous monomer may include a stream recovered in the oligomer manufacturing process.

The solvent contained in the feed stream may be supplied to the reactor as a feed stream. In some cases, as the solvent, the solvent recovered after use in the oligomer process may be reused.

According to an embodiment of the present invention, in the step of supplying the first discharge stream of the reactor to the first separation device and supplying the second discharge stream of the reactor to the second separation device, the separation device comprises a conventional distillation column. Can be used.

According to an embodiment of the present invention, the first discharge stream may be a stream containing a gaseous monomer. In the first separation device, an upper discharge stream including gaseous monomers may be supplied to a reactor, and a lower discharge stream including liquid monomers may be supplied to a second separation device. In this case, the upper discharge stream of the first separation device may be mixed with a gaseous monomer stream separately supplied to the reactor and supplied to the reactor by mixing in a mixer, or may be separately supplied to the reactor.

According to an embodiment of the present invention, the reactor second discharge stream may be supplied to a second separation device to be separated into an upper discharge stream containing a gaseous monomer and a lower discharge stream containing an oligomer product, a byproduct, and a solvent. have.

The gaseous monomer recovered as an upper discharge stream in the second separation device may be supplied to the reactor. In this case, the second separation device upper discharge stream may be mixed with the gaseous monomer stream and the first separation device upper discharge stream separately supplied to the reactor and supplied to the reactor by mixing in a mixer, or may be separately supplied to the reactor.

The second separation unit bottom effluent stream is fed to a third separation unit to be separated in a third separation unit into a liquid bottom effluent stream containing oligomers and solvents and a liquid top effluent stream containing C4 compounds as by-products. I can. In this case, the C4 compound may include 1-butene (1-C4).

The content of the C4 compound contained in the upper discharge stream of the third separation device may be 70% by weight or more. For example, the content of the C4 compound contained in the upper discharge stream of the third separation device may range from 70% to 99% by weight, 80% to 95% by weight, or 85% to 90% by weight. As such, the upper discharge stream of the third separation device including the C4 compound may be supplied to the second separation device, while the second separation device and the third separation device may have a circulation flow. At this time, by supplying the C4 compound as an upper discharge stream from the third separation device to the second separation device, the C4 compound having a lower boiling point compared to the oligomer product and the solvent may be concentrated in the lower portion of the second separation device. Through this, while recovering the unreacted monomer to the upper portion of the second separation device, the lower temperature is lowered, it is possible to effectively remove the concentrated C4 compound to the lower discharge stream.

The content of the concentrated C4 compound in the lower discharge stream of the second separation device may be 5% to 40% by weight. For example, the content of the C4 compound contained in the lower discharge stream of the second separation device may be 5% to 40% by weight, 10% to 30% by weight, or 13% to 20% by weight.

The second separation unit lower discharge stream containing the concentrated C4 compound is fed to a third separation unit, and the upper discharge stream containing 80% by weight or more C4 compounds is discharged from the third separation unit. In this case, the C4 compound can be efficiently separated by a method of branching and recovering some streams of the upper discharge stream of the third separation device to the second separation device. For example, the C4 compound may be selectively recovered by partially purging the upper discharge stream of the third separation device containing the C4 compound in a high content.

The content of the C4 compound contained in some streams of the upper discharge stream of the third separation device may be 70% by weight or more. For example, the content of the C4 compound contained in some streams of the upper discharge stream of the third separation device may range from 70% to 99% by weight, 80% to 95% by weight, or 85% to 90% by weight. . In addition, the content of monomers in some streams of the upper discharge stream of the third separation device may be 5% by weight or less. For example, the content of the monomer contained in some streams of the upper discharge stream of the third separation device may range from 0.01% to 5% by weight, from 0.1% to 3% by weight, or from 0.5% to 2% by weight. As described above, the oligomer manufacturing method according to the present invention minimizes the loss of monomer to 5% by weight or less, while purging some streams of the upper discharge stream of the third separation device to selectively recover the C4 compound as a by-product in the process. I can. Through this, when the C4 compound is removed by purging some streams of the unreacted monomer recovery stream without a separate C4 separation step due to low selectivity for the C4 compound in the conventional oligomer production method, the monomer is also removed along with the C4 compound, The problem that the loss of monomer was large was solved.

The content ratio of the C4 compound contained in the upper discharge stream of the third separation device to the content of the C4 compound contained in the second discharge stream of the reactor may be 2 or more and 2 to 7, 4 to 6. In this case, the upper discharge stream of the third separation device may mean a stream discharged from the upper portion of the third separation device and supplied to the second separation device. The content ratio of the C4 compound contained in the upper discharge stream of the third separation device to the content of the C4 compound contained in the second discharge stream of the reactor is determined by supplying the second discharge stream of the reactor to the second separation device, and the third It may mean a concentration ratio at which the C4 compound is concentrated in the second discharge stream of the reactor while partially circulating through the separation device. Specifically, by installing a third separation device at the rear end of the second separation device to concentrate the C4 compound at a concentration ratio of at least twice the C4 content in the second discharge stream of the reactor, the second separation device because the boiling point of the C4 compound is low. It is possible to obtain the effect of lowering the boiling point of the lower discharge stream of, and thus lower the temperature of the lower part while maintaining the pressure of the second separation device at high pressure. Specifically, when the concentration of the substance having a low boiling point is increased at the same pressure, the boiling point of the mixture is lowered, and thus the boiling point of the lower discharge stream of the second separation device can be lowered by concentrating the C4 compound. In this case, the boiling point of the stream discharged from the distillation column may refer to an operating temperature of the corresponding distillation column, and the boiling point of the lower discharge stream of the second separation device may refer to an operation temperature under the second separation unit.

According to an embodiment of the present invention, the pressure in the second separation device may be operated at a higher pressure than the pressure in the third separation device. Specifically, the second separation device may lower the bottom temperature while maintaining the upper temperature of the second separation device at a high temperature by discharging the lower discharge stream containing the monomer to the third separation device while operating at high pressure. Through this, side reactions of hydrocarbons can be suppressed. Specifically, by operating the pressure in the second separation device at high pressure while maintaining the upper temperature at a high temperature and lowering the lower temperature, unreacted monomers can be easily recovered from the upper part, and the oligomer produced at the lower part is decomposed, or other substances It is possible to prevent the occurrence of side reactions that react with and generate by-products.

The pressure in the second separation device may range from 12 bar to 25 bar, and the pressure in the third separation device may range from 3 bar to 15 bar. For example, the pressure in the second separation device may be 12 bar to 25 bar, 13 bar to 23 bar, or 14 bar to 20 bar, and the pressure in the third separation device is 3 bar to 15 bar, 4 bar to 13 bar. bar or 5 bar to 10 bar range. By controlling the pressure in the second separation device and the third separation device within the above range, it is possible to efficiently recover unreacted monomers without requiring a low-temperature refrigerant or a high compression ratio compressor in the second separation device and the third separation device. , In the lower part of the second separation device, the oligomer prepared through the oligomerization reaction of the monomer may be decomposed, or a side reaction of generating a by-product by reacting with other substances may be prevented.

The second separation device is operated at a high pressure, and the lower discharge stream of the second separation device is supplied to a third separation device operated at a low pressure, and a circulation flow between the high pressure second separation device and the low pressure third separation device By concentrating the C4 compound in the lower portion of the second separation device from, it is possible to lower the bottom temperature while maintaining the upper temperature of the second separation device high. Specifically, the temperature of the lower discharge stream of the second separation device may be 130 °C to 200 °C. For example, the temperature of the lower discharge stream of the second separation device may be 130°C to 200°C, 140°C to 190°C, or 150°C to 180°C.

According to an embodiment of the present invention, in the lower stream of the third separation device, the solvent and the oligomer may be separated through an additional separation process, and the separated solvent may be supplied to the reactor. In addition, the separated oligomer may be separated into monomer trimers and tetramers through an additional separation process.

According to the present invention, an apparatus for producing an oligomer is provided. The oligomer production apparatus, comprising: a reactor for oligomerizing a feed stream containing a supplied monomer, supplying a first discharge stream to a first separation device, and supplying a second discharge stream to a second separation device; A first separation device receiving the reactor first discharge stream; A second separation device for receiving the second discharge stream of the reactor, recovering the monomer as an upper discharge stream, and supplying the lower discharge stream to a third separation device; And a third separation device configured to receive the second separation device lower discharge stream and supply the upper discharge stream to the second separation device.

According to an embodiment of the present invention, the apparatus for manufacturing an oligomer according to the present invention may be an apparatus for performing a process according to the method for manufacturing an oligomer described above.

According to an embodiment of the present invention, the apparatus for producing an oligomer according to the present invention may be described with reference to FIG. 1 below. For example, the oligomer production apparatus includes a reactor 100 for oligomerizing a feed stream containing supplied monomers, and in the reactor 100, a first discharge stream containing a gaseous monomer is first The second discharge stream is supplied to the separation device 200 and includes a liquid monomer may be supplied to the second separation device 210.

According to an embodiment of the present invention, the feed stream supplied to the reactor 100 may include a monomer and a solvent. Specifically, the feed stream may contain a gaseous monomer and a solvent. The feed stream containing the gaseous monomer is a gaseous monomer stream directly supplied to the reactor 100, a gaseous monomer recovered as an upper discharge stream from the first separation device 200, and a second separation device 210 It may contain a gaseous monomer recovered as an upper discharge stream at. The gaseous monomer stream directly supplied to the reactor 100, the upper discharge stream of the first separation device 200 including the gaseous monomer, and the second separation device 210 upper discharge stream including the gaseous monomer are individually It may be supplied to the reactor 100 or may be supplied to the reactor 100 as a mixed discharge stream mixed in a mixer (not shown). The solvent may be separately supplied to the reactor 100, and in this case, the solvent separated after use in the process may be reused.

According to an embodiment of the present invention, the first separation device 200 receives the first discharge stream from the reactor 100 and converts the upper discharge stream including the gaseous monomer into the lower discharge stream including the liquid monomer. Can be separated. In this case, the upper discharge stream of the first separation device 200 may be supplied to the reactor 100, and the lower discharge stream may be supplied to the second separation device 210.

According to an embodiment of the present invention, the second separation device 210 receives the second discharge stream of the reactor 100 including the liquid monomer and the lower discharge stream of the first separation device 200, It can be separated into a top effluent stream comprising monomers and a bottom effluent stream comprising oligomeric products, by-products and solvents. In this case, the upper discharge stream of the second separation device 210 may be supplied to the reactor 100, and the lower discharge stream may be supplied to the third separation device 220.

The upper discharge stream of the second separation device 210 may pass through the compressor 300 and be supplied to the reactor 100. In this case, since the second separation device 210 is operated at a high pressure of 12 bar to 20 bar, there is an advantage of being economical in that a compressor 300 having a relatively low compression ratio may be used. Therefore, compared to the case of using the conventional high compression ratio compressor 300, it is possible to reduce the process cost.

The lower discharge stream of the second separation device 210 may be supplied to the third separation device 220, and an upper discharge stream including a by-product including a C4 compound may be supplied to the second separation device 210. In this case, the upper discharge stream of the third separation device 220 may be supplied to the second separation device 210 using the pump 400. Specifically, the pump 400 is used to supply the upper discharge stream of the third separation device 220 to the second separation device 210, in which the pressure of the upper discharge stream of the third separation device 220 is The pressure of the second separation device 210 may be increased.

Some streams of the upper discharge stream of the third separation device 220 may be recovered without being supplied to the second separation device 210. Specifically, the upper discharge stream of the third separation device 220 may be purged to recover some of the streams including the C4 compound, and the remaining stream may be supplied to the second separation device 210.

In the third separation device 220, a bottom effluent stream including an oligomer product and a solvent may be recovered. In this case, the oligomer product and the solvent contained in the lower discharge stream of the third separation device 220 may be separated through an additional separation device (not shown), and the separated solvent may be reused in the oligomer manufacturing process. Further, for example, when the oligomerization reaction is performed using an ethylene monomer as the monomer, the oligomer product may include 1-hexene and 1-octene. In this case, the 1-hexene and 1-octene may be separated through an additional separation device (not shown) or may be separated and used through a separate process.

According to an embodiment of the present invention, in some cases, a condenser (not shown) is provided above at least one of the first separation device 200, the second separation device 210, and the third separation device 220. May be additionally installed, and a reboilier (not shown) may be additionally installed in the lower part.

As described above, the oligomer manufacturing method and apparatus according to the present invention have been shown in the description and drawings, but the description and drawings in the above description and show only the essential configuration for understanding the present invention, as shown in the description and drawings. In addition to the processes and apparatuses, processes and apparatuses not separately described and not shown may be appropriately applied and used to implement the oligomer manufacturing method and apparatus according to the present invention.

Hereinafter, the present invention will be described in more detail by examples. However, the following examples are intended to illustrate the present invention, and that various changes and modifications are possible within the scope of the present invention and the scope of the technical idea is obvious to those skilled in the art, and the scope of the present invention is not limited thereto.

Example

Example 1

With respect to the process flow diagram shown in FIG. 1, the process was simulated using an Aspen Plus simulator manufactured by Aspen Tech. At this time, the lower discharge stream of the second separation device 210 is a stream that has passed through a reboiler (not shown), and the upper discharge stream of the third separation device 220 passes through a condenser (not shown). It is one stream, and the lower discharge stream of the third separation device 220 is a stream that has passed through a reboiler (not shown). In addition, ethylene (C2) as a monomer was supplied to the reactor 100 at a reaction amount of 20,000 kg/hr or more, and the reaction conditions of the reactor 100 were set at a temperature of 53° C. and a pressure of 30 bar, and the second separation The operating pressure of the device 210 was set to 15 bar, and the operating pressure of the third separation device 220 was set to 6 bar. The results are shown in Table 1 below.

	First stream		Second stream		Third stream		Stream 4		Stream 5		6th stream		7th stream
Temperature(℃)	53		45		160		41		43		41		161
Pressure (bar)	30		15		15		6		15		6		6
flux	Kg/hr	weight%	Kg/hr	weight%	Kg/hr	weight%	Kg/hr	weight%	Kg/hr	weight%	Kg/hr	weight%	Kg/hr	weight%
Ethylene	6861	14	6859	77	88	0	88	One	86	One	2	One	0	0
1-C4	1750	4	1604	18	8194	17	8193	85	8048	85	145	85	One	0
1-C6	9269	19	244	3	10279	21	1277	13	1254	13	23	13	9002	23
menstruum	20096	40	127	One	20022	40	53	One	52	One	One	One	19969	50
Heavy	10894	23	24	One	10871	22	One	0	One	0	0	0	10870	27
Total flow	48870	100	8858	100	49453	100	9611	100	9441	100	170	100	39842	100
* Heavy: a material having a higher molecular weight than the solvent * First stream: the second discharge stream of the reactor 100 supplied from the reactor 100 to the second separation device 210 * The second stream: the upper portion of the second separation device 210 Discharge Stream* Third Stream: Second Separation Unit 210 Bottom Discharge Stream* Fourth Stream: Third Separation Unit 220 Upper Discharge Stream* Fifth Stream: Third Separation Unit 220 to Pump 400 The supplied third separation unit 220 upper discharge stream* Sixth stream: Some streams of the third separation unit 220 upper discharge stream that are not supplied to the pump 400 and are recovered* Seventh stream: The third separation unit ( 220) bottom discharge stream

In the table of the present invention, the component flow rate in the stream is described by rounding to the first decimal place, and when the flow rate is expressed in weight%, it is calculated and described as the component flow rate content in the total flow rate. Referring to Table 1, the second separation device 210 and the third separation device 220 compared to the content of 1-C4 in the second discharge stream of the reactor 100 supplied to the second separation device 210 It can be seen that the content ratio of 1-C4 in the stream circulated back to the second separation device 210, that is, the concentration ratio of 1-C4, is concentrated to about 4.6, and as a result, the lower discharge stream of the second separation device 210 It could be seen that the content of 1-C4 in it was 17% by weight. In addition, the content of 1-C4 in the separated stream by purging a partial stream of the upper discharge stream of the third separation device 220 is 85% by weight, the content of ethylene monomer is 1% by weight, and the purity of 1-C4 is It is high, and it can be seen that there is little loss of ethylene monomer.

Example 2

The operation pressure of the second separation device 210 was set to 18 bar, and the operation pressure of the third separation device 220 was set to 8 bar . The results are shown in Table 2 below.

	First stream		Second stream		Third stream		Stream 4		Stream 5		6th stream		7th stream
Temperature(℃)	53		47		160		43		45		43		176
Pressure (bar)	30		18		18		8		18		8		8
flux	Kg/hr	weight%	Kg/hr	weight%	Kg/hr	weight%	Kg/hr	weight%	Kg/hr	weight%	Kg/hr	weight%	Kg/hr	weight%
Ethylene	6861	14	6857	77	286	One	286	2	282	2	4	2	0	0
1-C4	1750	4	1615	18	10023	19	10023	80	9888	80	135	80	0	0
1-C6	9269	19	237	3	11188	21	2185	17	2156	17	29	17	9003	23
menstruum	20096	41	118	One	20053	38	76	One	75	One	One	One	19977	50
Heavy	10894	22	23	0	10872	21	One	0	One	0	0	0	10871	27
Total flow	48870	100	8850	99	52423	100	12572	100	12403	100	169	100	39851	100
* Heavy: a material having a higher molecular weight than the solvent * First stream: the second discharge stream of the reactor 100 supplied from the reactor 100 to the second separation device 210 * The second stream: the upper portion of the second separation device 210 Discharge Stream* Third Stream: Second Separation Unit 210 Bottom Discharge Stream* Fourth Stream: Third Separation Unit 220 Upper Discharge Stream* Fifth Stream: Third Separation Unit 220 to Pump 400 The supplied third separation unit 220 upper discharge stream* Sixth stream: Some streams of the third separation unit 220 upper discharge stream that are not supplied to the pump 400 and are recovered* Seventh stream: The third separation unit ( 220) bottom discharge stream

Referring to Table 2, when the operating pressure of the second separation device 210 is set to 18 bar, and the operating pressure of the third separation device 220 is set to 8 bar, the upper portion of the third separation device 220 In the separated stream by purging some streams of the discharge stream, the content of 1-C4 is 80% by weight, the content of ethylene monomer is 2% by weight, the purity of 1-C4 is high, and the loss of ethylene monomer is almost In addition, compared to Example 1, the pressure of the second separation device 210 is high, but the concentration flow and the concentration ratio of 1-C4 are increased by increasing the fifth stream, so that the second separation device ( 210) The temperature of the lower discharge stream could be operated at 160 °C in the same manner as in Example 1.

Comparative example

Comparative Example 1

With respect to the process flow chart shown in FIG. 2, the process was simulated using the Aspen Plus simulator of Aspen Tech. At this time, the upper discharge stream of the second separation device 210 is a stream that has passed through a condenser (not shown), and the lower discharge stream of the second separation device 210 passes through a reboiler (not shown). It's a stream. In addition, ethylene (C2) as a monomer was supplied to the reactor 100 at a reaction amount of 20,000 kg/hr or more, and the reaction conditions of the reactor 100 were set at a temperature of 53° C. and a pressure of 30 bar, and the second separation The operating pressure of the device 210 was set to 15 bar. The results are shown in Table 3 below.

	1-1 stream		2-1 stream		Stream 3-1
Temperature(℃)	53		7		212
Pressure (bar)	30		15		15
flux	Kg/hr	weight%	Kg/hr	weight%	Kg/hr	weight%
Ethylene	6861	14	46861	81	0	0
1-C4	1750	4	1600	19	150	0
1-C6	9269	19	0	0	9268	23
menstruum	20096	41	0	0	20096	50
Heavy	10894	22	0	0	10894	27
Total flow	48870	100	8461	100	40409	100
* Heavy: a substance having a molecular weight greater than that of the solvent * 1-1 stream: the second discharge stream of the reactor 100 supplied from the reactor 100 to the second separation device 210 * The 2-1 stream: the second separation device (210) upper discharge stream * 3-1 stream: second separation device 210 lower discharge stream

Referring to Table 3, in Comparative Example 1, the second separation device 210 is operated at 15 bar as in Example 1, but if you look at the 3-1 stream, which is the lower discharge stream of the second separation device 210, , It can be seen that the temperature is 212 °C, which is significantly higher compared to the 160 °C of Example 1. In addition, even in the case of Example 2 where the operating pressure of the second separation device 210 is higher than 15 bar, the temperature of the lower discharge stream of the second separation device 210 is 160° C., which is significantly higher than that of Comparative Example 1. In addition, in the case of Examples 1 and 2, compared with the 1-C4 content in the lower discharge stream of the second separation device 210 is 17% by weight and 19% by weight, in the case of the comparative example, the separation device 210 It can be seen that the 1-C4 content in the bottom effluent stream is less than 0.5% by weight.

As a result, the reason that the temperature of the lower discharge stream of the second separation device 210 of Comparative Example 1 is high even when operating at the same pressure or a lower pressure is the third separation device to which the lower discharge stream of the second separation device 210 is connected. Due to the absence of 220 and the absence of the third separation device 220, the concentration of 1-C4 under the second separation device 210 is not performed.

Comparative Example 2

In Comparative Example 2, the comparative example above except that the operating pressure of the second separation device 210 was set to 6 bar in order to lower the lower temperature of the second separation device 210 to 160 °C as in Example 1. It was carried out in the same manner as in 2. The results are shown in Table 4 below.

	1-1 stream		2-1 stream		Stream 3-1
Temperature(℃)	53		-16		160
Pressure (bar)	30		6		6
flux	Kg/hr	weight%	Kg/hr	weight%	Kg/hr	weight%
Ethylene	6861	14	46861	81	0	0
1-C4	1750	4	1600	19	150	0
1-C6	9269	19	0	0	9269	23
menstruum	20096	41	0	0	20096	50
Heavy	10894	22	0	0	10894	27
Total flow	48870	100	8461	100	40409	100
* Heavy: a substance having a molecular weight greater than that of the solvent * 1-1 stream: the second discharge stream of the reactor 100 supplied from the reactor 100 to the second separation device 210 * The 2-1 stream: the second separation device (210) upper discharge stream * 3-1 stream: second separation device 210 lower discharge stream

Referring to Table 4, in Comparative Example 2, by operating the second separation device 210 at 6 bar, the temperature of the stream 3-1, which is the lower discharge stream of the second separation device 210, is 160 as in Example 1. Although lowered to °C, in this case, since about 24 bar must be raised to supply the upper discharge stream of the second separation device 210 discharged to the 6 bar to the reactor 100, the compression ratio is generally 3 times higher. It was confirmed that two compressors 300 should be used as shown in FIG. 3 below. In addition, compared to Example 1, since the pressure of the second separation device 210 was lowered while maintaining the composition of the stream supplied to the second separation device 210, the temperature of the 3-1 stream was lowered. The temperature of the 2-1 stream was also lowered to -16°C. As described above, in order to cool the upper discharge stream of the second separation device 210 to -16 °C, a refrigerant having a lower temperature level than refrigerants such as cooling water and ethylene glycol antifreeze generally used in the process must be used. There is a problem that driving costs are incurred.

Claims (12)

1. Supplying a feed stream containing monomers to the reactor to perform an oligomerization reaction;

   Supplying a first discharge stream of the reactor to a first separation device, and supplying a second discharge stream of the reactor to a second separation device;

   Recovering the monomer to the upper discharge stream of the second separation device, and feeding the lower discharge stream to a third separation device; And

   And feeding the top effluent stream of the third separation device to a second separation device.
2. The method of claim 1,

   The upper discharge stream of the third separation device is a liquid stream containing a C4 compound.
3. The method of claim 1,

   A method for producing an oligomer, wherein some of the streams of the upper discharge of the third separation device are recovered without being supplied to the second separation device.
4. The method of claim 3,

   The content of the C4 compound in some streams of the upper discharge stream of the third separation device is 70% by weight or more.
5. The method of claim 3,

   A method for producing an oligomer in which the content of monomers in some streams of the upper discharge stream of the third separation device is 5% by weight or less.
6. The method of claim 1,

   The content of the C4 compound in the lower discharge stream of the second separation device is 5% to 40% by weight of the oligomer production method.
7. The method of claim 1,

   A method for producing an oligomer wherein the content ratio of the C4 compound contained in the upper discharge stream of the third separation device to the content of the C4 compound contained in the second discharge stream of the reactor is 2 or more.
8. The method of claim 1,

   The pressure in the second separation device is higher than the pressure in the third separation device.
9. The method of claim 1,

   The pressure in the second separation device is 12 bar to 25 bar, and the pressure in the third separation device is 3 bar to 15 bar.
10. The method of claim 1,

    The temperature of the lower discharge stream of the second separation device is 130 ℃ to 200 ℃ oligomer production method.
11. The method of claim 1,

    The monomer is ethylene, and the oligomer is an alpha olefin.
12. A reactor for oligomerizing a feed stream containing the supplied monomers, supplying a first discharge stream to a first separation device, and supplying a second discharge stream to a second separation device;

    A first separation device receiving the reactor first discharge stream;

    A second separation device for receiving the second discharge stream of the reactor, recovering the monomer as an upper discharge stream, and supplying the lower discharge stream to a third separation device; And

    An oligomer production apparatus comprising a third separation device receiving the second separation device lower discharge stream and supplying the upper discharge stream to a second separation device.

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