Separation method of aromatic compounds comprising simulated moving bed xylene mixture pre-treatment process and additional xylene isomerization process (Samsung Total Petrochemicals)

PATENT
Separation method of aromatic compounds comprising simulated moving bed xylene mixture pre-treatment process and additional xylene isomerization process (Samsung Total Petrochemicals)
Publication number US8431763 B2
Application number US 12/532,751
Publication date Apr 30, 2013
Also published as CN101675016A, CN101675016B, US20100145119, WO2008133384A1
Inventors
Jin-Suk Lee, Hyun-Chul Kim
Original Assignee
Samsung Total Petrochemicals Co., Ltd.
Abstract
Disclosed is a method for separating aromatic compounds using a simulated moving bed adsorptive chromatography, comprising a sulfolan process that is a non-aromatic compound removing process, a benzene/toluene fractionation process, an aromatic compound fractionation process, a selective toluene disproportionation process, a transalkylation process, a simulated moving bed para-xylene separation process and a xylene isomerization process, wherein the method is characterized by further comprising a simulated moving bed xylene mixture pre-treatment process and an additional xylene isomerization process. The separation method of aromatic compounds according to the present invention can make significant improvement in para-xylene and benzene production in the overall process, as compared to the conventional aromatic compound separation process.
Description
TECHNICAL FIELD
The present invention relates to a method for separating aromatic compounds comprising a simulated bed xylene mixture pre-treatment process and an additional xylene isomerization process, specifically to a method for separating aromatic compounds using a simulated moving bed adsorptive chromatography, comprising a sulfolan process that is a non-aromatic compound removing process, a benzene/toluene fractionation process, an aromatic compound fractionation process, a selective toluene disproportionation process, a transalkylation process, a simulated moving bed para-xylene separation process and a xylene isomerization process, wherein the method is characterized by further comprising a simulated moving bed xylene mixture pre-treatment process and an additional xylene isomerization process.
BACKGROUND ART
A process of separating aromatic compounds is to obtain para-xylene and benzene as main final products by processing a naphtha feedstock in a petrochemical plant. To obtain para-xylene, one of important products among aromatic compounds, a process of separating it from a xylene mixture has been commonly used. As examples of such process, there are processes using simulated moving bed adsorptive chromatography and crystallization caused by freezing point difference in each component, or a hybrid process which uses both processes together by connecting them serially, and the like.
DISCLOSURE OF INVENTION Technical Problem
In a process of separating aromatic compounds using a conventional simulated moving bed adsorptive chromatography as shown in FIG. 1, the simulated moving bed para-xylene separation process is only used as a process for separating para-xylene. Such process has some problems that there is limitation on increasing reformate production by inputting additional naphtha, and on enhancing productivity of para-xylene by further adding toluene, due to the limited capacity of a simulated moving bed para-xylene separation process, and it is further required to improve productivity in terms of para-xylene production since the excess xylene mixture which could not be processed in the simulated moving bed para-xylene separation process should be discharged.
Technical Solution
The present invention has been developed to resolve the conventional technical problems in prior arts. The object of the present invention is to provide a method for separating aromatic compounds using a simulated bed adsorptive chromatography, which can increase para-xylene concentration, hence being able to separate para-xylene in efficient way and effectively converting the excess xylene mixture into para-xylene by pretreating a xylene mixture through a simulated moving bed xylene mixture pre-treatment process and an additional xylene isomerization process; and can significantly improve the overall productivity of para-xylene and toluene by inputting a separate toluene mixture as well as a xylene mixture.
In order to achieve the forgoing purposes, the method for separating aromatic compounds according to the present invention, which uses a simulated moving bed adsorptive chromatography, comprising a sulfolan process that is a non-aromatic compound removing process, a benzene/toluene fractionation process, an aromatic compound fractionation process, a selective toluene disproportionation process, a transalkylation process, a simulated moving bed para-xylene separation process and a xylene isomerization process, is characterized by further comprising a simulated moving bed xylene mixture pre-treatment process and an additional xylene isomerization process.
The xylene mixture pre-treatment process and the additional xylene isomerization process preferably comprise the following steps of:
(1) inputting a part of a xylene mixture that is to be inputted to a simulated moving bed para-xylene separation process, to the simulated moving bed xylene mixture pre-treatment process;
(2) inputting a xylene mixture containing 80% by weight or more para-xylene in the resulted product obtained from said simulated moving bed xylene mixture pre-treatment process, to the simulated moving bed para-xylene separation process, and the remaining portion of the xylene mixture is inputted to the additional xylene isomerization process;
(3) re-inputting the resulted product obtained from said additional xylene isomerization process to said aromatic compound fractionation process.
In the step (1), the amount of a xylene mixture to be inputted to a simulated moving bed xylene mixture pre-treatment process is not specifically limited, and it may be suitably adjusted depending on the system conditions, however, preferably being 50˜200 tons/hour.
In the step (3), a part of the product obtained from an additional xylene isomerization process, which is to be inputted to an aromatic compound fractionation process, may be inputted to a benzene/toluene fractionation process. The amount thereof to be inputted is not specifically limited, and it may be suitably adjusted depending on the system conditions, however, preferably being 1˜10 tons/hour.
In the method for separating aromatic compounds, overall productivity of para-xylene may be improved, by additionally inputting toluene to a selective disproportionation process. Further, in the method for separating aromatic compounds, a xylene mixture can be additionally inputted to said aromatic compound fractionation process so as to improve overall productivity of para-xylene. Each amount of separate toluene and the separate xylene mixture to be inputted is not specifically limited, and it may be suitably adjusted depending on the system conditions, however preferably being 0˜60 tons/hour and 0˜30 tons/hour, respectively
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