SU884262A1 - Process for producing aromatic hydrocarbons - Google Patents

Description

The temperature and pressure of the feedstock are fractions of benzium reforming in the presence of a bifunctional catalyst containing H-mordenite, metals of the VI side and / or group VIII, alumina, and the feedstock is preliminarily subjected to distillation to separate the hydrocarbon fraction containing aromatic hydrocarbons € $ -Cs.

It is preferable to carry out the separation of the hydrocarbon fraction to achieve a content of aromatic Ce hydrocarbons in the feedstock of 0.3-30 wt. %

The admixture of aromatic hydrocarbons Ce in this fraction does not exceed USD 30 weight. % If, in a known method, aromatized gasoline is subjected to catalytic processing after distilling off the benzene fraction (up to 100-105 ° C), then according to the proposed method, it is proposed to pre-separate the head fraction containing all benzene, toluene and the maximum possible amount of aromatic GS (total xylenes) present in the initial gasoline, in order to send the catalytic fraction of the aromatic sous with a content of aromatic Ce up to 30 wt. %

With this preparation of the raw material, the yield of xylenes to the fraction subjected to catalytic processing and to the whole aromatized gasoline is higher than in the known method, and the total yield of benzene, toluene, and xylenes is higher.

The above shch / a fraction consists mainly of aromatic hydrocarbons Ce, which are represented by isomers of trimethyl benzenes and ethyl toluenes. It may also contain small amounts (2-5 wt.%) Of Xu's aromatic hydrocarbons (tetramethylbenzenes, diethyltoluenes, ethylxylene), which usually occur in aromatized gasoline. Precisely, it is difficult to separate aromatic GS and Cd o-xylene and some isomers of aromatic Gg. Go to the invention, the effectiveness of the application of the proposed method is manifested if the content of aromatic C & in the fraction of aromatic Gg is no more than 30 wt.%. Below this critical soda rye xylene yield exceeds their content in the feedstock, i.e., newly formed xylenes are obtained. As can be seen from examples 2, 3, 4 below (see Table 1), the yield of newly formed xylenes (aromatic GS) is greater, the less they are contained in the fraction of the aromatic Gg subjected to catalytic processing. However, there is no need to reduce their content below 0.3 wt.%, as a further decrease does not give any appreciable (within the limits of analysis) growth of the gs.

It was found that regardless of the content of aromatic Gg (xnolol) in the catalytically processed raw material, the yield of this raw material of all products (benzene, toluene, xylenes) is almost the same. So the yield of xylenes is approximately pasei; 34- 35 weight. % When the content of xylene

raw material 30 wt. The% yield of newly formed xylenes is only 4-5 (34-30 wt.%). In the absence of xylenes in the raw material, the yield of newly formed xylenes is 34-35 wt. % GyMMapHb output VTK on

the catalytically processed fraction is 3-5 times higher than in the known method. Higher yields of xylenes and the total yield of HFC to the initial aromatic benz.and (taking into account the aromatic hydrocarbons contained in the overhead fraction). The yield of xylenes and VTK on the original gasoline is 1.5-1.6 times higher than in the known method of processing. In practice, the process is carried out as follows. Aromatic gasoline, for example, obtained by a catalytic reforming process or pyrolysis, is rectified to separate the head fraction boiling to 145-

150 ° G, and the effluent fraction is sent to catalytic processing at 400-580 ° G and a pressure of 10-50 atm in the presence of mordium-containing catalysts. Pure xylenes and toluene are isolated

rectification. Unconverted aromatic hydrocarbons Gg can be recycled.

GaMa catalytic processing is carried out as in the known method with

temperatures of preferably 450-500 ° G, pressures of 10-50 atm in the presence of any of the known catalysts containing mordenite-alumina-hydrogenating metal.

Example 1 (comparative). Catalytic reforming gasoline is used as flavored gasoline. From gasoline reforming to distillation

column efficiency 25 theor. the plates are distilled off the head fraction boiling to 105 ° G. The above boiling fraction 105 ° G — the end of the boil (q) is used for catalytic processing. GocTaB source

gasoline reforming, weight. %: non-aromatic 27; benzene 5.6; toluene 18.6; aromatic Ge 24.8; aromatic Gg-GIO 24.0. The high boiling gasoline fraction (composition is given below) is passed from

hydrogen-containing gas through a catalyst containing 5% MoO3, 45% H-mordenite, 55% alumina at 475 ° G and pressure of 35 atm. The volumetric feed rate is 2, the rate of circulation of the hydrogen-containing gas is 1600 nl / l, the feed of fresh hydrogen is 150 nl / l. In tab. one

the composition of the processed raw material

(fractions 105 ° C K. K.), the yield of products and

the yield of newly formed benzene, toluene and xylenes (BTC) on the processed

raw material

Table 1

From the data of the example, it is clear that the total growth of the CTC is due to the bin. ash and toluene, and the yield of aromatic C .. even decreases.

PRI mme R 2. A fraction is thoroughly distilled from the starting gasoline ri4 orming.

The total yield of the newly formed VTK is 55.9%, including the increase in aromatic GS 34.7.

boiling up to 147 ° C. The above boiling part of the reforming gasoline is sent for catalytic processing under the conditions and on the catalyst as per example 1. In the table. 2 gives the composition of the feedstock, the yield of liquid products and the yield of the newly formed VTKTable 2

Example 3. A fraction boiling away to 145 ° C is distilled from the aromatized gasoline. The effluent of the reforming gasoline is sent to catalytic non-processing under the conditions and on the catalyst, corresponding to example I. Table. 3

The total yield of the newly formed VTK 41.9 wt. %, including the increase in aromatic GS (xylenes) 20.3 wt. %

Example 4. From the aromatized gasoline, the fraction boiling away to 144 ° C is distilled off. The boiling part of the gasoline is reformed. The total yield of the newly formed ICC is 27.1 wt. %, including aromatic Cs (xylenes) only 4.9%. In tab. 5 summarizes the outputs of the newly formed WTC in examples 1-4. It can be seen that during processing

given the composition of the processed raw material, the yield of liquid products and the yield of the newly formed BTKTable 3

Minga is sent for catalytic processing under the conditions and on the catalyst corresponding to Example 1. In the table. 4 gives the composition of the raw material being processed, the yield of liquid products and the yield of the newly formed BTKTable 4

raw materials containing predominantly aromatic Cd, the yield of newly formed xylenes and BTC is significantly higher than with the implementation of the known method. The increase in VTK in a known method of processing

is 11.4 wt. %, and in the proposed from 27.1 to 55.9 weight. % depending on co - sign is marked reduction.

In tab. 6 cites data on the yield of the total CTA and whole reformate, taking into account the aromatic hydrocarbons contained in the reformate head fraction. The proposed method allows to increase the yield of xylenes and total BTC in 1.5-

: Note: ep 5. For the catalytic processing, the raw materials of example 3 are used. The raw materials are passed with a hydrogen-containing gas through a catalyst containing 1% Co, 5% MoO3, 45% H-mordenite, 54% alumina, at a pressure of 10 atm and a temperature of 400 ° C. The volumetric feed rate of h; gas 2, the multiplicity of circulation of hydrogen-containing gas is 1600 nl / l of raw material, the supply of fresh hydrogen is 150 nl / l of raw material. The product yield is by weight. %: non-aromatic 0.3; benzene 1,3; toluene 8.0; aromatic ce 20.3; Aromatic Cd 60.5; Xu 4.5. Xylene gain 5.8 wt. %, while in example 3 - 20.3 weight. % Example 5 illustrates the lower limit of temperature and pressure, when it is still feasible to implement the method.

keep aromatic C in the processed raw materials.

Table 5

1.6 times compared with the known method (see examples 1 and 2, 3). With a critical content of aromatic Ce 30 wt. % in the processed raw material benefits are minimal (see examples 1 and 4).

Table 6

Example 6. The test was carried out on the feedstock under the conditions of Example 5, with the exception of temperature and pressure, which are 580 ° C and 50 atm. The product yield is by weight. %: non-aromatic 0.05; benzene 6.5; toluene 29.1; aromatic C 23.8; aromatic sd 17.1; aromatic C; about 2.0. Xylene gain 9.3 wt. % while in example 3 - 20.3 wt. % The example describes the upper limit of temperature and pressure at which the implementation of the method is expedient.

Claims (2)

Invention Formula I. The method of producing aromatic hydrocarbons by hydrodealkylation of hydrocracking at elevated temperatures and pressures of the raw material — a fraction of reforming gasolines in the presence of a bifunctional catalyst containing H-mordenite, metals of VI and secondary and / or VIII groups, alumina, characterized in that the yield of the target products, the feedstock is pre-subjected to distillation with the separation of hydrocarbon fractions containing aromatic hydrocarbons Sb-Ce. 2. A method according to claim 1, characterized in that the separation of the hydrocarbon fraction is carried out until the content of aromatic hydrocarbons Cs in the feedstock is equal to 0.3-30 wt. % The source of information taken in. attention during examination: 1. USSR author's certificate No. 726073, cl. C 07 C 15/02, 1975.