KR101948440B1 - Treating method of dearomatized hydrocarbon for the production of n-hexane, iso-hexane and heptane mixture - Google Patents

Abstract

The present invention relates to a dearomatized oil treatment method combining distillation and simulated moving bed processes for preparing isohexane and heptane at 95% purity as well as normal hexane with a purity of 63-99% from the dearomatized oil. The dearomatized oil treatment method can increase the value of the dearomatized oil components.

Description

(Treating method of dearomatized hydrocarbon for the production of n-hexane, iso-hexane and heptane mixture) to produce a mixture of n-hexane, isohexane and heptane from de-

The present invention relates to a process for producing a dearomatized oil fraction (hereinafter also referred to as "dearomatic oil fraction") produced as a by-product in an aromatic treatment process (hereinafter referred to as an "aromatic process" To prepare a mixture of isohexane and heptane of various purity of normal hexane and 95% purity.

An aromatic compound treatment process (hereinafter also referred to as "aromatic process") is a process for producing par-xylene (PX) and benzene (BZ) by treating naphtha as a raw material. In a conventional aromatic process, a source process for producing a mixed xylene containing para-xylene (PX), which is one of main products, is a reformer process, a xylene isomerization process, And transalkylation and disproportionation of aromatic compounds having 9 carbon atoms. Figure 1 shows a schematic diagram of a typical aromatics treatment process.

Since benzene and xylene, which are main products of aromatic process, are aromatic compounds, in aromatic processes such as these, aromatic products are removed from aromatics in the sulfolane process as byproducts, which are simply naphtha cracking centers (Naphtha Cracking Center) has been used only as a raw material and has not been high-priced.

The object of the present invention is to provide a dearomatic oil fraction discharged as an aromatic process by-product, as a raw material, and to provide a dearomatic oil fraction which is used only as a raw material of a naphtha cracking center, To provide a mixture of isohexane and heptane of normal purity of 63% and 99% purity of normal hexane and 95% purity, thereby providing a method of treating a dearomatic oilseed which is remarkably improved in profitability as a whole.

The dearomatized oil produced as a byproduct of the aromatic process is introduced into the first distillation column to remove light components of less than 5 carbon atoms and then introduced into the second distillation column to separate into a flow of 6 carbon atoms and a flow of 7 or more When the olefin is removed by adding it to the hydrogenation reactor and then introduced into the third distillation column, 63% n-hexane can be obtained at the bottom of the distillation column. Native hexane of 99% purity is passed through the drier to remove the water from the upper stream of the second distillation tower and the bottom stream of the fourth distillation tower. The extract stream is injected into the distillation column, Isohexane having a purity of 95% is prepared by: (a) feeding the upper stream of the tertiary distillation column to the fourth distillation column and recovering 95% isohexane from the upper part of the fourth distillation column; Hexane, or (b) raffinate stream from the pseudo-mobile layer is injected into the distillation column to recover the desorbent at the top of the distillation column and to produce isohexane at 95% purity as the bottom. In the simulated moving bed, one selected from n-paraffin, propane, butane and pentane, which has a lower boiling point than hexane, is used as a desorbent and can be easily separated from the distillation column for reuse. The pseudo moving bed apparatus is disclosed in detail in Korean Patent Laid-Open Publication No. 10-2007-0067926 (2007. 06. 29) and Korean Patent Laid-Open Publication No. 10-2007-0067925 (2007. 06. 29) It is not mentioned separately.

On the other hand, if the heavier components of more than 8 carbon atoms are removed from the bottom of the second distillation tower through the additional distillation column, the heptane mixture consisting of only 7 carbon atoms is obtained.

According to the dearomatic oil treatment process of the present invention, it is possible to produce a mixture of n-hexane, isohexane and heptane of various purity using a dearomatic oil fraction discharged as a by-product in an aromatic process. Therefore, (Naphtha Cracking Center) As compared with the case where only the raw material is used, the profitability can be remarkably improved by effectively recycling by-products.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic process diagram of an aromatic process for producing para-xylene in general.
Figure 2 is a schematic diagram of a process for producing a mixture of n-hexane, isohexane and heptane from de-aromatics.

Hereinafter, the present invention will be described in more detail by way of examples and comparative examples, but the scope of the present invention is not limited by these examples and comparative examples.

Comparative Example

In the aromatic compound treatment process having the constitution as shown in Fig. 1, when the dearomatic oil fraction produced as a by-product is simply used as a raw material for naphtha cracking center, the value of the oil fraction can be said to be the same as that of naphtha.

Example

In the aromatic compound treatment process, the dearomatic oil fraction produced as a by-product is treated with the process shown in FIG. 2 to produce an isohexane / heptane mixture having a purity of normal purity of n-hexane of 63% and 99% . The effect of improving the mass balance and profitability of each flow shown in FIG. 2 according to this embodiment is shown in Table 1 below.

A6: aromatic group having 6 carbon atoms
A7: aromatic group having 7 carbon atoms
A8: 8-carbon aromatic
A9: 9-carbon aromatic
A8's: 8 carbons
A10 < + >: aromatic having 10 or more carbon atoms
Col 1: distillation column 1
Col 2: distillation column 2
Col 3: Distillation column 3
Col 4: Distillation column 4
RX 1: Hydrogenation reactor 1
RX 2: Hydrogenation Reactor 2
SMB: Pseudo moving bed separation device
C5 to C6: C5 to C6
C7 +: C 7 +
C7s: 7 carbon atoms
C8s: 8 carbon atoms

Claims (5)

A method for treating dearomatic oils, characterized in that de-aromatics are treated to obtain a mixture of n-hexane of 63% and 99% purity and of isohexane and heptane of 95% purity,
(i) The n-hexane having the 63% purity can be obtained by introducing the dearomatic oil fraction into the distillation column 1 to remove the light component having 5 or less carbon atoms and removing the dearomatic The oil was introduced into the distillation column 2 and separated into a stream having six carbon atoms and a stream having seven or more carbon atoms. The separated stream of six carbon atoms was fed to the hydrogenation reactor 1 to remove the olefin, ) To produce 63% of normal hexane in the lower portion of the distillation column 3,
(ii) The n-hexane having a purity of 99% is prepared by passing the upper stream of the distillation column 2 and the lower stream of the distillation column 4 through a drier to remove water and then removing the moisture from the distillation column 2, 4) The lower stream is injected into the pseudo-mobile layer, and the extract stream is injected into the distillation column from the stream discharged therefrom. The desorbent is recovered to the upper part of the distillation column, and 99% or more of high purity normal hexane is produced ,
(iii) isohexane of 95% purity can be prepared by (a) introducing the stream above the distillation column 3 into the distillation column 4 to produce 95% isohexane from the top of the distillation column 4, or (b) The raffinate stream from the bed is injected into the distillation column to recover the desorbent to the top of the distillation column and to produce isohexane of 95% purity as the bottom.
(iv) As the heptane mixture, a stream having 7 or more carbon atoms derived from the lower part of the distillation column 2 is introduced into the distillation column 5 to remove the oil having 8 carbon atoms below the distillation column. 2) to produce a heptane mixture having 7 carbon atoms. The method according to claim 1, wherein at least one selected from n-propane, n-butane and n-pentane is used as the desorbing agent for the pseudo-mobile layer.
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