KR20210037415A - METHOD AND APPARATUS FOR PREPARING n-HEXANE - Google Patents

Abstract

The present invention relates to a method and apparatus for preparing n-hexane. Particularly, the present invention relates to a method capable of saving energy in separating n-hexane from a feed stream containing non-aromatic hydrocarbons. The method according to the present invention includes the steps of: supplying a feed stream containing non-aromatic hydrocarbons to a first distillation column, supplying a partial stream of the stream discharged from the bottom of the first distillation column to the first distillation column by way of a first heat exchanger, and supplying a partial stream of the stream discharged from the top of the first distillation column to a second distillation column by way of a second heat exchanger; supplying the stream discharged from the top of the second distillation column to the first heat exchanger to carry out heat exchange with the partial stream of the stream discharged from the bottom of the first distillation column and supplied to the first heat exchanger; supplying a partial stream of the stream discharged from the bottom of the second distillation column to the second heat exchanger to carry out heat exchange with the partial stream of the stream discharged from the top of the first distillation column and supplied to the second heat exchanger; and separating n-hexane from the partial stream of the stream discharged from the bottom of the second distillation column and heat exchanged in the second heat exchanger.

Description

Manufacturing method and manufacturing apparatus of n-hexane TECHNICAL FIELD [METHOD AND APPARATUS FOR PREPARING n-HEXANE}

The present invention relates to a method and apparatus for producing n-hexane, and more particularly, to a method for saving energy in separating n-hexane from a feed stream containing non-aromatic hydrocarbons.

The naphtha cracking process (Naphtha Cracking Center; hereinafter referred to as'NCC') thermally decomposes naphtha, a gasoline fraction, at a temperature of about 950°C to 1,050°C, and ethylene, propylene, butylene, which are basic raw materials for petrochemical products, and It is a process that produces BTX (Benzene, Toluene, Xylene), etc.

The NCC process is a process of decomposing naphtha into hydrocarbons with a small number of carbon atoms by applying heat. In the above process, naphtha and circulating ethane, which are liquid raw materials, are mixed with diluted steam and then decomposed in a high-temperature decomposition furnace. In addition, the material at the outlet of the decomposition furnace is rapidly cooled to about 400° C. while passing through a heat exchanger, and after producing high-pressure steam, it is rapidly cooled by cooling oil and sent to a gasoline rectification tower (quick cooling process). The quenching process is a process of lowering the temperature in order to suppress the reaction between decomposed hydrocarbons. In this process, pyrolysis fuel oil (PFO) including tar is generated in the lower part of the gasoline rectifier tower, and the gas at the top is sent to the quenching tower to be separated into cracked gasoline (RPG) and light oil.

The RPG is separated into BTX, which is an aromatic hydrocarbon, and a group of non-aromatic hydrocarbons, through a subsequent separation and purification process. At this time, the non-aromatic hydrocarbon group contains C6 hydrocarbons including n-hexane. At this time, the recovery of n-hexane, an active component of the C6 hydrocarbon, consumes a lot of energy because the difference in boiling point between the main substances is small. Accordingly, it is necessary to develop a process for separating n-hexane of the C6 hydrocarbons to the level of crude n-Hexane while saving energy.

KR 1699632 B

The problem to be solved in the present invention is to provide an energy-saving method for producing n-hexane in order to solve the problems mentioned in the background technology of the present invention.

That is, in the present invention, crude n-hexane is separated from a feed stream containing non-aromatic hydrocarbons using a first distillation column and a second distillation column, and waste heat in the process is removed using a first heat exchanger and a second heat exchanger. It is an object of the present invention to provide a method and apparatus for producing n-hexane that reduces energy used in the process by recycling.

According to an embodiment of the present invention for solving the above problems, in the present invention, a feed stream containing a non-aromatic hydrocarbon is supplied to a first distillation column, and some streams of the lower discharge stream of the first distillation column are first Supplying the first distillation column through a heat exchanger, and supplying a partial stream of the upper discharge stream to the second distillation column through a second heat exchanger; Supplying the second distillation column upper discharge stream to the first heat exchanger to heat exchange with a partial stream of the first distillation column lower discharge stream supplied to the first heat exchanger; Supplying a partial stream of the second distillation column lower discharge stream to the second heat exchanger to heat exchange with a partial stream of the first distillation column upper discharge stream supplied to the second heat exchanger; And separating n-hexane from a partial stream of a lower discharge stream of the second distillation column heat-exchanged in the second heat exchanger.

In addition, in the present invention, a feed stream containing non-aromatic hydrocarbons is supplied, some streams of the lower discharge stream pass through the first heat exchanger and are supplied to the first distillation column, and some streams of the upper discharge stream pass through the second heat exchanger. A first distillation column that is supplied to the second distillation column; A partial stream of the upper discharge stream of the first distillation column passing through the second heat exchanger is supplied, the upper discharge stream is supplied to the first heat exchanger, and a partial stream of the lower discharge stream is supplied to the second heat exchanger, and the second heat exchanger A second distillation column for separating n-hexane from a partial stream of the bottoms discharge stream passing through the group; A first heat exchanger for exchanging a partial stream of the supplied first distillation column lower discharge stream and a second distillation column upper discharge stream; And a second heat exchanger for exchanging a partial stream of the supplied first distillation column upper discharge stream and a partial stream of the second distillation column lower discharge stream.

According to the method for producing n-hexane of the present invention, crude n-hexane is separated from a feed stream containing a non-aromatic hydrocarbon using a first distillation column and a second distillation column, and a first heat exchanger and a second heat exchanger are used. By using the waste heat in the process, it is possible to reduce the energy used in the process.

1 is a flowchart of a method for preparing n-hexane according to an embodiment of the present invention.
2 to 6 are process flow diagrams of a method for preparing n-hexane 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 a conventional or dictionary meaning, 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 the flow of fluid in the process, and may also mean the fluid itself flowing in the pipe. Specifically, the'stream' may mean both the fluid itself and the flow of the fluid flowing in a pipe connecting each device. In addition, the fluid may mean gas or liquid.

In the present invention,'heat exchanger' may be used as a meaning including a condenser installed at the top of the distillation column, a reboiler installed at the bottom of the distillation column, and a separate heat exchanger.

In the present invention, the term'C# hydrocarbons' in which'#' is a positive integer refers to all hydrocarbons having # carbon atoms. Thus, the term'C4 hydrocarbon' refers to a hydrocarbon compound having 4 carbon atoms. Also, the term'C#+ hydrocarbon' refers to all hydrocarbon molecules having # or more carbon atoms. Thus, the term'C5+ hydrocarbon' refers to a mixture of hydrocarbons having 5 or more carbon atoms.

Hereinafter, the present invention will be described in more detail with reference to FIG. 1 to aid in understanding the present invention.

According to the present invention, a method for preparing n-hexane (n-Hexane) is provided. In the n-hexane production method, a feed stream containing a non-aromatic hydrocarbon is supplied to the first distillation column 100, and some streams of the lower discharge stream of the first distillation column 100 are the first heat exchanger 300 Passing through the first distillation column 100 and supplying a partial stream of the upper discharge stream to the second distillation column 200 through the second heat exchanger 400; Supplying the upper discharge stream of the second distillation column 200 to the first heat exchanger 300 to exchange heat with a partial stream of the lower discharge stream of the first distillation column 100 supplied to the first heat exchanger 300 step; A partial stream of the upper discharge stream of the first distillation column 100 supplied to the second heat exchanger 400 by supplying a partial stream of the lower discharge stream of the second distillation column 200 to the second heat exchanger 400 Heat-exchanging with; And separating n-hexane from a partial stream of a lower discharge stream of the second distillation column 200 heat-exchanged in the second heat exchanger 400.

According to an embodiment of the present invention, the feed stream may contain non-aromatic hydrocarbons. For example, the feed stream may be a BTX stream separated in an NCC process. The BTX stream may contain C6 non-aromatic hydrocarbons. The content of C6 non-aromatic hydrocarbons in the feed stream may be 50% to 80% by weight. For example, the content of C6 non-aromatic hydrocarbons in the feed stream may be 55% to 75% by weight, 60% to 75% by weight, or 65% to 75% by weight.

The C6 non-aromatic hydrocarbon contained in the feed stream may include n-hexane. The content of n-hexane in the feed stream may be 5% to 30% by weight. For example, the content of n-hexane in the feed stream may be 10% to 30% by weight, 10% to 25% by weight, or 10% to 20% by weight.

The C6 non-aromatic hydrocarbon contained in the feed stream has a problem in that a large amount of energy is required to separate n-hexane from the C6 non-aromatic hydrocarbon due to a small difference in boiling point between the main substances. Specifically, the C6 non-aromatic hydrocarbon contained in the feed stream has a problem in that a large amount of energy is required to separate n-hexane from the C6 non-aromatic hydrocarbon due to a small difference in boiling point between the main substances. For example, the main substances of the C6 non-aromatic hydrocarbon may include n-hexane, 3-methylpentane, and methyl cyclopentane. At this time, the boiling point of the n-hexane is about 68.1 °C, the boiling point of 3-methylpentane is about 63 °C, the boiling point of methyl cyclopentane is about 71.8 °C, it can be seen that the difference between the boiling point between the main substances is small. Therefore, a lot of energy is required to separate n-hexane from the feed stream. On the other hand, in the present invention, in separating n-hexane from the feed stream at the level of crude n-hexane, there is provided a method of separating n-hexane at low energy by recycling waste heat in the process.

According to an embodiment of the present invention, the feed stream may include C6 non-aromatic hydrocarbons, as well as light C4 and C5 non-aromatic hydrocarbons and Heavies C7+ hydrocarbons.

The content of C4 and C5 non-aromatic hydrocarbons in the feed stream may be less than or equal to 0.1% by weight. For example, the content of C4 and C5 non-aromatic hydrocarbons in the feed stream may be 0.001 wt% to 0.08 wt%, 0.005 wt% to 0.05 wt%, or 0.008 wt% to 0.03 wt%.

The content of C7+ non-aromatic hydrocarbons in the feed stream may be 15% to 25% by weight. For example, the content of C4 and C5 non-aromatic hydrocarbons in the feed stream may be 0.001 wt% to 0.08 wt%, 0.005 wt% to 0.05 wt%, or 0.008 wt% to 0.03 wt%.

According to an embodiment of the present invention, the feed stream containing the non-aromatic hydrocarbon is supplied to the first distillation column 100, and some streams of the lower discharge stream of the first distillation column 100 are included in the first heat exchanger ( 300) and supplied to the first distillation column 100, and the remaining stream may be separated.

The feed stream containing the non-aromatic hydrocarbon is supplied to the first distillation column 100, and a stream containing Heavies Non Aromatic hydrocarbons and n-hexane and Lights Non Aromatic hydrocarbons through distillation. It can be separated into a stream containing. In this case, the light non-aromatic hydrocarbon may mean a material having a molecular weight less than that of n-hexane, and the heavy non-aromatic hydrocarbon may mean a material having a molecular weight greater than that of n-hexane.

In the first distillation column 100, heavy non-aromatic hydrocarbons may be separated from the bottom discharge stream. Specifically, some streams of the lower discharge stream of the first distillation column 100 may be supplied to the first heat exchanger, and the remaining streams may be separated. In this case, the remaining stream of the lower discharge stream of the first distillation column 100 to be separated may contain heavy non-aromatic hydrocarbons.

Some streams of the lower discharge stream of the first distillation column 100 supplied to the first heat exchanger 300 may be heated while passing through the first heat exchanger 300 and then be refluxed to the first distillation column 100. have.

The upper discharge stream of the first distillation column 100 is supplied to a first condenser 110, and a partial stream of the upper discharge stream of the first distillation column 100 from the first condenser 110 is a second heat exchanger 400 ), and the remaining stream may be condensed and refluxed to the first distillation column 100. At this time, some streams of the upper discharge stream of the first distillation column 100 supplied to the second heat exchanger 400 without refluxing to the first distillation column 100 are n-hexane and light non-aromatic ) May contain hydrocarbons.

According to an embodiment of the present invention, some streams of the upper discharge stream of the first distillation column 100 that has passed through the second heat exchanger 400 are supplied to the second distillation column 200 and n-hexane is distilled through distillation. And a stream containing light non-aromatic hydrocarbons.

In the second distillation column 200, n-hexane may be separated from the lower discharge stream. Specifically, the lower discharge stream of the second distillation column 200 is supplied to the second reboiler 220 and heated, and the lower discharge stream of the second distillation column 200 heated in the second reboiler 220 Some streams are discharged through the second heat exchanger 400, and the remaining streams may be refluxed to the second distillation column 200. In this case, n-hexane may be separated from a partial stream of the lower discharge stream of the second distillation column 200 discharged through the second heat exchanger 400.

Light non-aromatic hydrocarbons may be separated from the upper discharge stream of the second distillation column 200. Specifically, the upper discharge stream of the second distillation column 200 is supplied to the first heat exchanger, and some streams of the upper discharge stream of the second distillation column 200 that have passed through the first heat exchanger 300 are separated and discharged. Then, the remaining stream may be refluxed to the second distillation column 200. In this case, some streams of the upper discharge stream of the second distillation column 200 discharged through the first heat exchanger 300 may contain light non-aromatic hydrocarbons.

According to an embodiment of the present invention, the operating pressure of the second distillation column 200 may be 2.8 Kg/sqcmG or more higher than the operating pressure of the first distillation column 100. For example, the operating pressure of the second distillation column 200 is 2.8 Kg/sqcmG to 5 Kg/sqcmG, 2.8 Kg/sqcmG to 4.5 Kg/sqcmG or 2.8 Kg/ than the operating pressure of the first distillation column 100 sqcmG to 3.5 Kg/sqcmG can be high. In this way, by operating the second distillation column 200 at a pressure of 2.8 Kg/sqcmG or more higher than the pressure of the first distillation column 100, the first distillation column 100 provides heavy non-aromatic hydrocarbons and the second distillation column ( In 200), n-hexane and light non-aromatic hydrocarbons can be easily separated. In addition, by operating the second distillation column 200 at a pressure of 2.8 Kg/sqcmG or higher than that of the first distillation column 100, the operating temperature of the second distillation column 200 is also increased to a high temperature. Accordingly, the temperature of the stream discharged to the top and the stream discharged to the bottom of the second distillation column 200 may be higher than the temperature of the stream discharged to the top and the stream discharged to the bottom of the first distillation column 100. Accordingly, waste heat of the high-temperature streams discharged from the second distillation column 200 may be reused to heat the streams discharged from the first distillation column 100 to save energy. Through this, it is possible to solve the problem that a lot of energy is required in the conventional process of separating n-hexane.

The operating pressure of the first distillation column 100 may be -0.5 Kg/sqcmG to 3.5 Kg/sqcmG, and the operating pressure of the second distillation column 200 may be 2.3 Kg/sqcmG to 6.3 Kg/sqcmG. For example, the operating pressure of the first distillation column 100 may be-0.5 Kg/sqcmG to 3.0 Kg/sqcmG,-0.5 Kg/sqcmG to 2.0 Kg/sqcmG or-0.5 Kg/sqcmG to 0.5 Kg/sqcmG. In addition, the operating pressure of the second distillation column 200 may be 2.3 Kg/sqcmG to 6.0 Kg/sqcmG, 2.3 Kg/sqcmG to 5.5 Kg/sqcmG, or 2.3 Kg/sqcmG to 5.0 Kg/sqcmG. By controlling the operating pressure of the first distillation column 100 and the second distillation column 200 within the above range, n-hexane can be separated at the level of crude n-hexane, and energy consumption in the process can be reduced.

According to an embodiment of the present invention, the reflux ratio of the upper discharge stream of the second distillation column 200 to the reflux ratio of the upper discharge stream of the first distillation column 100 may be 0.5 to 1.5. In this case, the reflux ratio of the upper discharge stream of the first distillation column 100 is compared to the total flow rate of the stream discharged to the upper part of the first distillation column 100, and the upper discharge stream of the first distillation column 100 is the first condenser. It may represent a flow rate that passes through 110 and is refluxed to the first distillation column 100. In addition, the reflux ratio of the upper discharge stream of the second distillation column 200 is compared to the total flow rate of the stream discharged to the upper part of the second distillation column 200, and the upper discharge stream of the second distillation column 200 is the first heat exchanger 300. It may represent a flow rate that passes through and reflux to the second distillation column 200.

The reflux ratio of the upper discharge stream of the second distillation column 200 to the reflux ratio of the upper discharge stream of the first distillation column 100 may be 0.5 to 1.4, 0.8 to 1.3, or 1.0 to 1.3. The reflux ratio of the upper discharge stream of the second distillation column 200 to the reflux ratio of the upper discharge stream of the first distillation column 100 satisfies the above range, so that the first distillation column 100 and the second distillation column 200 are This allows the separation of n-hexane from the feed stream without the need for an additional condenser or reboiler.

According to an embodiment of the present invention, the first distillation column 100 supplied to the first heat exchanger 300 by supplying the upper discharge stream of the second distillation column 200 to the first heat exchanger 300 Heat exchange with some of the streams in the bottoms effluent stream can be achieved.

As described above, the upper discharge stream of the second distillation column 200 may be high temperature compared to the lower discharge stream of the first distillation column 100. Therefore, by exchanging heat with a partial stream of the upper discharge stream of the second distillation column 200 and the lower discharge stream of the first distillation column 100 in the first heat exchanger 300, the first heat exchanger 300 2 Waste heat from the upper discharge stream of the distillation column 200 may be transferred to a partial stream of the lower discharge stream of the first distillation column 100 to heat a partial stream of the lower discharge stream of the first distillation column 100. In this case, the waste heat of the upper discharge stream of the second distillation column 200 may be latent heat contained in the upper discharge stream of the second distillation column 200. Accordingly, a temperature after passing through some streams of the lower discharge stream of the first distillation column 100 may be high compared to a temperature before passing through the first heat exchanger 300. In this way, some streams of the lower discharge stream of the first distillation column 100 are heated in the first heat exchanger 300 by using waste heat of the upper discharge stream of the second distillation column 200, and the heated first distillation column ( 100) By refluxing some streams of the lower discharge stream to the first distillation column 100, energy that must be used in the reboil of the first distillation column 100 and the condenser of the second distillation column 200 can be reduced. .

Due to the installation of the first heat exchanger 300, a partial stream of the lower discharge stream of the first distillation column 100 is heated to reflux to the first distillation column 100 and the second distillation column 200 is It may not be necessary to install a condenser for condensing some of the streams of the upper discharge stream and refluxing it to the second distillation column 200. Specifically, in the first heat exchanger 300, a partial stream of the lower discharge stream of the first distillation column 100 and the upper discharge stream of the second distillation column 200 are exchanged to each other, so that the lower discharge stream of the first distillation column 100 Some streams of are heated, and some streams of the upper discharge stream of the second distillation column 200 are condensed. In this way, by replacing the first heat exchanger 300 with the first heat exchanger 300 without installing a reboiler and a condenser, respectively, in the first distillation column 100 and the second distillation column 200, the waste heat in the process is reused to reduce the process cost. can do.

Among the upper discharge streams of the second distillation column 200 passing through the first heat exchanger 300, the stream that is not condensed while passing through the first heat exchanger 300 is separated and discharged, and the first heat exchanger 300 The stream condensed while passing through may be refluxed to the second distillation column 200. In this case, some of the separated and discharged streams of the upper discharge stream of the second distillation column 200 passing through the first heat exchanger 300 may be a stream containing light non-aromatic hydrocarbons.

According to an embodiment of the present invention, a first distillation column supplied to the second heat exchanger 400 by supplying a partial stream of the lower discharge stream of the second distillation column 200 to the second heat exchanger 400 (100) It can be heat-exchanged with some streams of the overhead discharge stream. Specifically, the lower discharge stream of the second distillation column 200 is supplied to the second condenser 210, and some streams that have passed through the second condenser 210 are supplied to the second heat exchanger 400, and the rest The stream may be refluxed to the second distillation column 200. In this case, a partial stream of the lower discharge stream of the second distillation column 200 supplied to the second heat exchanger 400 is a part of the upper discharge stream of the first distillation column 100 supplied to the second heat exchanger 400 It can heat exchange with the stream.

As described above, the lower discharge stream of the second distillation column 200 may be high temperature compared to the upper discharge stream of the first distillation column 100. Accordingly, in the second heat exchanger 400, by exchanging a partial stream of the lower discharge stream of the second distillation column 200 and a partial stream of the upper discharge stream of the first distillation column 100 in the second heat exchanger 400, the second heat exchanger 400 The waste heat of the partial stream of the lower discharge stream of the second distillation column 200 of the high temperature is transferred to a partial stream of the upper discharge stream of the first distillation column 100 to heat the partial stream of the upper discharge stream of the first distillation column 100. I can. Accordingly, a temperature after passing through a partial stream of the upper discharge stream of the first distillation column 100 may be high compared to a temperature before passing through the second heat exchanger 400. In this way, a partial stream of the upper discharge stream of the first distillation column 100 is heated in the second heat exchanger 400 by using waste heat of a partial stream of the lower discharge stream of the second distillation column 200, and the heated first By supplying a partial stream of the upper discharge stream of the distillation column 100 to the second distillation column 200, a partial stream of the upper discharge stream of the first distillation column 100 is preheated before being supplied to the second distillation column 200. I can. In this way, by preheating a partial stream of the upper discharge stream of the first distillation column 100 and supplying it to the second distillation column 200, the upper discharge of the first distillation column 100 supplied from the second distillation column 200 It is possible to save energy for heating some of the streams.

Further, according to the present invention, an apparatus for producing n-hexane for carrying out the method for producing n-hexane is provided.

In the n-hexane production apparatus according to an embodiment of the present invention, a feed stream containing a non-aromatic hydrocarbon is supplied, and some streams of the lower discharge stream pass through the first heat exchanger 300 to pass through the first distillation column 100. ) And supplying a partial stream of the upper discharge stream to the second distillation column 200 through the second heat exchanger 400; A partial stream of the upper discharge stream of the first distillation column 100 that has passed through the second heat exchanger 400 is supplied, and the upper discharge stream is supplied to the first heat exchanger 300, and a partial stream of the lower discharge stream is A second distillation column 200 that is supplied to the second heat exchanger 400 and separates n-hexane from a partial stream of the bottom discharge stream that has passed through the second heat exchanger 400; A first heat exchanger 300 for exchanging a partial stream of the lower discharge stream of the first distillation column 100 and the upper discharge stream of the second distillation column 200 supplied; And a second heat exchanger 400 for exchanging a partial stream of an upper discharge stream of the first distillation column 100 and a partial stream of a lower discharge stream of the second distillation column 200.

According to an embodiment of the present invention, the first distillation column 100 distills a feed stream containing non-aromatic hydrocarbons supplied to separate heavy non-aromatic hydrocarbons from the bottom discharge stream, and n-hexane and light non-aromatic The upper discharge stream containing hydrocarbons may be supplied to the second distillation column 200.

According to an embodiment of the present invention, the apparatus for producing n-hexane may include a first condenser 110 installed on the first distillation column 100. The first condenser 110 condenses the upper discharge stream of the first distillation column 100 to be supplied, and some streams of the discharge stream of the first condenser 110 pass through the second heat exchanger 400 to provide a second It is supplied to the distillation column 200, and the remaining stream may be refluxed to the first distillation column 100. In this case, some streams of the upper discharge stream of the first distillation column 100 passed through the second heat exchanger 400 and supplied to the second distillation column 200 contain n-hexane and light non-aromatic hydrocarbons. I can.

According to an embodiment of the present invention, the second distillation column 200 is supplied with a partial stream of the upper discharge stream of the first distillation column 100 that has passed through the second heat exchanger 400, and the supplied first The distillation column 100 may be distilling a partial stream of the upper discharge stream to separate n-hexane from the lower discharge stream, and to separate light non-aromatic hydrocarbons from the upper discharge stream.

According to an embodiment of the present invention, the apparatus for producing n-hexane may include a second reboiler 220 installed below the second distillation column 200. The second reboiler 220 heats the lower discharge stream of the second distillation column 200 supplied, and some streams of the discharge stream of the second reboiler 220 pass through the second heat exchanger 400 and are discharged. And, the remaining stream may be refluxed to the second distillation column 200. In this case, some streams of the lower discharge stream of the second distillation column 200 discharged through the second heat exchanger 400 may include n-hexane.

According to an embodiment of the present invention, the first heat exchanger 300 may heat-exchange a partial stream of the lower discharge stream of the first distillation column 100 and the upper discharge stream of the second distillation column 200 to be supplied. . Specifically, the first heat exchanger 300 may serve as the first reboiler 120 from the side of some streams of the lower discharge stream of the first distillation column 100, and the second distillation column 200 It may serve as the second condenser 210 from the side of the upper discharge stream.

According to an embodiment of the present invention, the second heat exchanger 400 heat-exchanges a partial stream of the upper discharge stream of the first distillation column 100 and a partial stream of the lower discharge stream of the second distillation column 200 to be supplied. Can be. Specifically, the second heat exchanger 400 may serve as a preheating device for preheating a partial stream of the upper discharge stream of the first distillation column 100 before supplying it to the second distillation column 200.

According to an embodiment of the present invention, if necessary in the n-hexane production apparatus, a distillation column, a condenser, a reboiler, a pump, a compressor, and a separation device may be additionally installed.

Above, the description and drawings of the method for preparing n-hexane according to the present invention have been shown in the description and drawings, but the description and drawings are described and illustrated only in the essential configuration for understanding the present invention, and are 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 carry out the method for producing n-hexane 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 can be made within the scope of the present invention and the scope of the technical idea are 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 the Aspen Plus simulator of Aspen Tech. At this time, the operating pressure of the first distillation column 100 is -0.2 Kg/sqcmG, the operating pressure of the second distillation column 200 is 3.2 Kg/sqcmG, and the reflux ratio of the upper discharge stream of the first distillation column 100 is 2 The reflux ratio (K) of the upper discharge stream of the distillation column 200 was controlled to 1.170, and the composition of the feed stream supplied to the first distillation column 100 is shown in Table 1 below, and the simulation results are shown in Table 2 below. Indicated.

Specifically, a feed stream containing a non-aromatic hydrocarbon is supplied to the first distillation column 100, and the upper discharge stream of the first distillation column 100 is supplied to the first condenser 110, and the first condenser ( 110) Some streams of the discharge stream were supplied to the second heat exchanger 400, and the remaining streams were refluxed to the first distillation column 100.

In addition, some streams of the lower discharge stream of the first distillation column 100 were supplied to the first heat exchanger 300 to exchange heat with the upper discharge stream of the second distillation column 200, and the remaining streams were discharged. At this time, the remaining stream of the lower discharge stream of the first distillation column 100 that is separated and discharged contains heavy non-aromatic hydrocarbons.

In addition, some streams of the upper discharge stream of the second distillation column 200 heat-exchanged in the first heat exchanger 300 were separated and discharged, and the remaining streams were refluxed to the second distillation column 200. In this case, some streams of the upper discharge stream of the second distillation column 200 discharged through the first heat exchanger 300 contain light non-aromatic hydrocarbons.

In addition, the lower discharge stream of the second distillation column 200 is supplied to the second reboiler 220, and some streams of the lower discharge stream of the second distillation column 200 passing through the second reboiler 220 are removed. 2 was fed to a heat exchanger, and the remaining stream was refluxed to the second distillation column (200). At this time, crude n-hexane was separated from a partial stream of the lower discharge stream of the second distillation column 200 heat-exchanged in the second heat exchanger 400.

ingredient Content (% by weight) C4 0.01 C5 5.85 Other C6 21.29 C7 16.14 C8 6.96 C9 & Heavies 0.09 Light C6 4.21 n-Heaxane 14.61 Heavy C6 30.83 Water 0.01 Sum 100.00

Comparative example

Comparative Example 1

With respect to the process flow diagram shown in FIG. 2, the process was simulated using the Aspen Plus simulator of Aspen Tech. At this time, the operating pressure of the first distillation column 100 is 0.6 Kg/sqcmG, the operating pressure of the second distillation column 200 is 0.6 Kg/sqcmG, and the second distillation column 100 is compared to the reflux ratio of the upper discharge stream. The reflux ratio (K) of the upper discharge stream of the distillation column 200 was controlled to be 0.393, the composition and flow rate of the feed stream supplied to the first distillation column 100 were the same as in Example 1, and the simulation result is shown in Table 2 below. Shown in.

Specifically, a feed stream containing a non-aromatic hydrocarbon is supplied to the first distillation column 100, and the upper discharge stream of the first distillation column 100 is supplied to the first condenser 110, and the first condenser ( 110) Some streams of the discharge stream were refluxed to the first distillation column 100, and the remaining streams containing light non-aromatic hydrocarbons were separated.

In addition, the lower discharge stream of the first distillation column 100 is supplied to the first reboiler 120, and some streams of the discharge stream of the first reboiler 120 are refluxed to the first distillation column 100, The remaining stream was fed to the second distillation column 200.

In addition, in the second distillation column 200, the lower discharge stream of the first distillation column 100 passed through the supplied first reboiler 120 is distilled, and the upper discharge stream is supplied to the second condenser 210. , Some streams of the discharge stream of the second condenser 210 were refluxed to the second distillation column 200, and crude n-hexane was separated from the remaining stream.

In addition, the lower discharge stream of the second distillation column 200 is supplied to the second reboiler 220, and some streams of the discharge stream of the second reboiler 220 are refluxed to the second distillation column 200, The remaining stream containing heavy non-aromatic hydrocarbons was separated.

Comparative Example 2

With respect to the process flow diagram shown in FIG. 3, the process was simulated using the Aspen Plus simulator of Aspen Tech. At this time, the operating pressure of the first distillation column 100 is-0.2 Kg/sqcmG, the operating pressure of the second distillation column 200 is 2.5 Kg/sqcmG, and the reflux ratio of the upper discharge stream of the first distillation column 100 is reduced. 2 The reflux ratio (K) of the upper discharge stream of the distillation column 200 was controlled to 1.132, the composition and flow rate of the feed stream supplied to the first distillation column 100 were the same as in Example 1, and the simulation results are shown in the following table. It is shown in 2.

Specifically, a feed stream containing a non-aromatic hydrocarbon is supplied to the first distillation column 100, and the upper discharge stream of the first distillation column 100 is supplied to the first condenser 110, and the first condenser ( 110) Some streams containing n-hexane and light non-aromatic hydrocarbons in the discharge stream were fed to the second distillation column 200, and the remaining streams were refluxed to the first distillation column 100.

In addition, some streams of the lower discharge stream of the first distillation column 100 are supplied to the first heat exchanger 300, heat exchanged with the upper discharge stream of the second distillation column 200, and then transferred to the first distillation column 100. Refluxed. In addition, the remaining stream containing heavy non-aromatic hydrocarbons in the lower discharge stream of the first distillation column 100 was separated and discharged.

In addition, some streams containing light non-aromatic hydrocarbons in the upper discharge stream of the second distillation column 200 heat-exchanged in the first heat exchanger 300 are separated and discharged, and the remaining streams are transferred to the second distillation column 200. Refluxed.

In addition, the lower discharge stream of the second distillation column 200 is supplied to the second reboiler 220, and crude n- Some streams containing hexane were separated and discharged, and the remaining streams were refluxed to the second distillation column (200).

Comparative Example 3

The simulation was performed in the same manner as in Comparative Example 2, but the operating pressure of the second distillation column 200 was 3.2 Kg/sqcmG, compared to the reflux ratio of the upper discharge stream of the first distillation column 100. The reflux ratio (K) was controlled to 0.486 to separate crude n-hexane. The simulation results are shown in Table 2 below.

Comparative Example 4

The simulation was performed in the same manner as in Comparative Example 3, but crude n-hexane was separated by controlling the reflux ratio (K) of the upper discharge stream of the second distillation column 100 to the reflux ratio of the upper discharge stream of the first distillation column 100 to 1.965. I did. The simulation results are shown in Table 2 below.

Comparative Example 5

The simulation was performed in the same manner as in Comparative Example 3, but crude n-hexane was separated by controlling the reflux ratio (K) of the upper discharge stream of the second distillation column 100 to the reflux ratio of the upper discharge stream of the first distillation column 100 to 1.170. I did. The simulation results are shown in Table 2 below.

Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 First distillation column Upper pressure
(Kg/sqcmG) -0.2 0.6 -0.2 -0.2 -0.2 -0.2 1st condenser energy (Gcal/hr) -2.84 -3.22 -2.83 -3.08 -2.81 -2.84 1st reboiling energy (Gcal/hr) 2.76 3.21 2.78 3.00 2.73 2.76 Second distillation column Upper pressure
(Kg/sqcmG) 3.2 0.6 2.5 3.2 3.2 3.2 1st condenser energy (Gcal/hr) -2.76 -1.28 -2.78 -1.35 -4.46 -2.76 1st reboiling energy (Gcal/hr) 2.84 1.33 2.90 1.51 4.62 2.92 Energy of the first heat exchanger (Gcal/hr) 2.76 0.00 0.00 1.35 2.73 2.76 Second heat exchanger energy (Gcal/hr) 0.08 0.00 0.00 0.00 0.00 0.00 Total energy consumption (Gcal/hr) 2.84 4.54 5.68 3.16 4.62 2.92 Energy saving rate (%) 37.44 - -25.11 30.40 -1.76 35.68 Reflux ratio (K) 1.170 0.393 1.132 0.486 1.965 1.170 Whether you need additional devices X X O O O X

In Table 2, the total energy consumption was calculated as the first reboil energy + the second reboil energy-the first heat exchanger energy.

In addition, the energy saving rate is calculated by calculating the reduction rate of the total energy consumption of each of Example 1 and Comparative Examples 2 to 5 compared to the total energy consumption of Comparative Example 1 without the first heat exchanger and the second heat exchanger.

Referring to Table 2, in the case of Example 1, in preparing n-hexane from a feed stream, a first heat exchanger 300 and a second heat exchanger 400 were installed to provide a conventional n- Compared to the hexane production method, it showed an energy saving rate of about 37% or more.

In the case of Comparative Example 2, the first heat exchanger 300 is provided, but the second heat exchanger 400 is not provided, and the pressure difference between the first distillation column 100 and the second distillation column 200 As a result of controlling to less than 2.8 Kg/sqcmG, heat exchange is impossible in the first heat exchanger 300. As shown in FIG. 4, the first reboiler 120 and the second reboiler 120 and the second There is a problem in that a second condenser 210 needs to be additionally installed on the top of the distillation column.

In the case of Comparative Example 3, the first heat exchanger 300 was provided, but the second heat exchanger 400 was not provided, and as a result of controlling the K value to 0.486 and less than 0.5, the first distillation column ( The amount of energy required by 100) is greater than the amount of energy that can be provided by the second distillation column 200. Accordingly, in this case, as shown in FIG. 5 below, there is a problem in that the first reboiler 120 must be additionally installed under the first distillation column 100.

In the case of Comparative Example 4, the first heat exchanger 300 was provided, but the second heat exchanger 400 was not provided, and as a result of controlling the K value to 1.965 and exceeding 1.5, the first distillation column The amount of energy required by (100) becomes smaller than the amount of energy that can be provided by the second distillation column (200). Accordingly, in this case, as shown in FIG. 6 below, there is a problem in that a second condenser 210 must be additionally installed on the second distillation column 200.

In the case of Comparative Example 5, it can be seen that compared to Example 1, the second heat exchanger 400 is not installed, so that the energy saving rate is somewhat lower.

In addition, in comparison with Comparative Examples 1 to 5, Example 1 reduces the amount of energy used in the condenser, reboiler, and heat exchanger as shown in Table 2, and at the same time, the second heat exchanger 400 2 By preheating the stream supplied to the distillation column 200, energy required to heat the stream supplied from the second distillation column 200 may be reduced.

100: first distillation column 110: first condenser
120: first reboiler 200: second distillation column
210: second condenser 220: second reboiler
300: first heat exchanger 400: second heat exchanger

Claims (11)

A feed stream containing non-aromatic hydrocarbons is supplied to a first distillation column, a partial stream of the first distillation column bottom discharge stream is passed through a first heat exchanger to be supplied to the first distillation column, and a partial stream of the top discharge stream is Supplying a second distillation column through a second heat exchanger;
Supplying the second distillation column upper discharge stream to the first heat exchanger to heat exchange with a partial stream of the first distillation column lower discharge stream supplied to the first heat exchanger;
Supplying a partial stream of the second distillation column lower discharge stream to the second heat exchanger to heat exchange with a partial stream of the first distillation column upper discharge stream supplied to the second heat exchanger; And
And separating n-hexane from a partial stream of a lower discharge stream of the second distillation column heat-exchanged in the second heat exchanger. The method of claim 1,
A method for producing n-hexane in which some streams of the upper discharge stream of the second distillation column heat-exchanged in the first heat exchanger are separated and the remaining streams are supplied to the second distillation column. The method of claim 1,
The method for producing n-hexane wherein the feed stream contains C6 non-aromatic hydrocarbons. The method of claim 1,
The operating pressure of the second distillation column is 2.8 Kg/sqcmG or more higher than the operating pressure of the first distillation column. The method of claim 4,
The operating pressure of the first distillation column is-0.5 Kg/sqcmG to 3.5 Kg/sqcmG,
The operation pressure of the second distillation column is 2.3 Kg/sqcmG to 6.3 Kg/sqcmG of n-hexane production method. The method of claim 1,
The method for producing n-hexane wherein the reflux ratio of the second distillation column upper discharge stream to the reflux ratio of the first distillation column upper discharge stream is 0.5 to 1.5. The method of claim 1,
A method for producing n-hexane in which some streams of the lower discharge stream of the first distillation column have a high temperature after passing compared to a temperature before passing through the first heat exchanger. The method of claim 1,
A method for producing n-hexane in which some streams of the first distillation column upper discharge stream have a high temperature after passing compared to a temperature before passing through the second heat exchanger. The method of claim 1,
The method for producing n-hexane to separate heavy non-aromatic hydrocarbons from the bottom of the first distillation column. The method of claim 1,
The method for producing n-hexane to separate light non-aromatic hydrocarbons from the second distillation column overhead stream. A feed stream containing non-aromatic hydrocarbons is supplied, some streams of the bottom effluent stream pass through the first heat exchanger and are fed to the first distillation column, and some streams of the top effluent stream pass through the second heat exchanger to the second distillation column. A first distillation column to be supplied to the first distillation column;
A partial stream of the upper discharge stream of the first distillation column that has passed through the second heat exchanger is supplied, the upper discharge stream is supplied to the first heat exchanger, a partial stream of the lower discharge stream is supplied to the second heat exchanger, and the second heat exchanger A second distillation column for separating n-hexane from a partial stream of the bottoms discharge stream passing through the group;
A first heat exchanger for exchanging a partial stream of the supplied first distillation column lower discharge stream and a second distillation column upper discharge stream; And
An n-hexane production apparatus comprising a second heat exchanger for exchanging a partial stream of the supplied first distillation column upper discharge stream and a partial stream of the second distillation column lower discharge stream.

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