CS238584B1 - A method for obtaining indine from pyrolysis products - Google Patents

Abstract

Method of petrochemical processing of crude oil. Isolation of indene from pyrolysis products is carried out by separating pyrolysis oil from pyrolysis gas, after which heavy pyrolysis gasoline is separated from it by condensation in a water scrubber at temperatures of 30 to 85 °C, to which heavy pyrolysis gasoline obtained from condensates of compression of pyrolysis gas to a pressure of 0.5 to 1.2 MPa at a temperature of 35 to 45 °C is optionally added, and lighter hydrocarbons are separated from this liquid mixture by distillation, and as a residue, a fraction with an indene content of over 20% by weight is obtained, which can be further enriched by rectification to a content of over 60% by weight.

Description

(54)

Process for obtaining indsn from pyrolysis products

Method of petrochemical processing of crude oil. The isolation of indene from the pyrolysis products is effected by separating pyrolysis oil from the pyrolysis gas, followed by condensation in a scrubber at temperatures of 30 to 85 ° C to remove heavy pyrolysis gasoline, optionally to which heavy pyrolysis gasoline obtained from compression condensates is added. of pyrolysis gas to a pressure of 0.5 to 1.2 MPa at a temperature of 35 to 45 ° C and from this liquid mixture the lighter hydrocarbons are separated by distillation and a fraction with an indene content above 20% by weight is obtained as a residue which can be further enriched to content over 60 wt.

238 584

238 584

The invention relates to a process for the manufacture of pyrolysis products. In the production of ethylene by pyrolysis of gaseous and liquid hydrocarbon feedstocks at temperatures of 780 to 840 ° C, pyrolysis gasoline is produced as a by-product, which is a mixture of hydrocarbons up to Ο ^ θ and a distillation range of approximately 45 to 190 ° C.

Pyrolysis gasoline contains numerous hydrocarbons, of which isoprene, benzene, toluene, styrene and indene are particularly valuable. The composition of pyrolysis gasoline depends on the raw material used and the sharpness of the pyrolysis regime. Hydrocarbons present in a significant amount in the pyrolysis products include cyclopentadiene, which yields up to 35% by weight with respect to all pyrolysis when the pyrolysis is sharp. An important feature of this hydrocarbon is that it undergoes dimerization to dicyclopentadiene (DCPD) during the formation and processing of pyrolysis gasoline, with a degree of dimerization conversion depending on operating conditions of 50-8056. Because of this, DCPD predominates in hydrocarbons contained in pyrolysis gasoline. The remaining part Ο ^ θ ^. The hydrocarbons are predominantly C 1-4 aromatics. In case of sharp pyrolysis of heavy gasoline, the composition of pyrolysis gasoline is eg:

hydrocarbons % wt 17.7 C 1 -C 8 non-aromatics 15.8 benzene 28.1 Toluene 13.9 Aromθ aromáty 10.8 aromatics 6.4 ^C 104 - ^A hydrocarbon (DCPD) 9.3

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Isoprene and aromatic hydrocarbons - benzene, toluene, xylene are normally obtained from pyrolysis gasoline. Hydrocarbons with an isoprene content of about 20% are first distilled off. The remaining gasoline is subjected to hydrogenation to the first stage to remove most reactive conjugate diolefins and aromatic olefins (styrene). The hydrogenation also converts indene to indane. The hydrogenate is usually separated by distillation into a fraction Ο ^ α, ιθ, from which ae are obtained by aromatics by distillation, extraction or various dealkylation processes, and fraction ^C 9+> which serves mainly as a component of motor fuels. This scheme varies according to the requirement for the production of isoprene or aromatics and thus, for example, all pyrolysis gasoline can be hydrogenated or some fractions can be hydrogenated to the second stage.

Pyrolysis gasoline is a mixture of hydrocarbon fractions that fall off in the process of condensation and separation of pyrolysis products. The heaviest proportion of pyrolysis gasoline condenses in a water scrubber, following the technological stage in which pyrolysis oils are separated from the pyrolysis gas. The condensation takes place at a temperature of 30 to 45 ° C at the head and 75 to 85 ° C at the bottom of the scrubbing column at a pressure of 0.03 to 0.08 MPa. Another proportion of heavy pyrolysis gasoline is formed by hydrocarbon condensates which condense after each stage of pyrolysis gas compression at pressure levels of 0.5 to 1.2 MPa at temperatures of 35 to 45 ° C. Light pyrolysis gasoline consists of hydrocarbon condensates, which condense at individual stages of compression at pressures higher than 0.5 to 1.2 MPa »These condensates are further rectified together with liquefied proportions of pyrolysis gas, while the light pyrolysis gasoline is obtained as a distillation residue debutanizer where ee relieves hydrocarbons.

It has now been found that by appropriately mixing the various proportions of pyrolysis gasoline as condensed in the process of condensing and separating pyrolysis products and selecting operating conditions, a suitable separation of pyrolysis gasoline into light and heavy pyrolysis gasoline can be achieved so that heavy gasoline contains all indene formed during pyrolysis Conversely, the pyrolysis hydrocarbons are virtually free of isoprene and cyclopentadiene, which are almost exclusively contained in light pyrolysis gasoline ·

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The advantage of this distinction is that the heavy pyrolysis gasoline contains all the indene formed during the pyrolysis and is virtually free of cyclopentadiene, which is concentrated in light pyrolysis gasoline. This separation allows to rectify the indene fraction which does not contain dicyclopentadiene from the pyrolysis gasoline. Indene and dicyclopentadiene cannot be separated due to near boiling points. Dicyclopentadiene contained in the pyrolysis gasoline in a significant amount, in this case significantly reduces the concentration of indene in the rectified separation indene fraction, but above all complicates the subsequent use of the indene fraction. . In the de-distillation treatment of only heavy pyrolysis gasoline, this problem is eliminated since virtually all dicyclopentadiene is contained in light pyrolysis gasoline, where it is formed by dimerization of the pyrolysis cyclopentadiene.

The process for the isolation of indene from pyrolysis products is characterized in that only the heavy pyrolysis gasoline obtained from the pyrolysis gas after separation of the pyrolysis oils by condensation in a water scrubber at a pressure of 0.03 to 0.08 MPa and a temperature of 30 to 45 ° C at the top and 75 to 85 ° C at the bottom of the scrubber, to which optionally pyrolysis gasoline obtained from the pyrolysis gas compression condensates is added to a pressure of 0.5 to 1.2 MPa at a temperature of 35 to 45 ° C. From this hydrocarbon mixture with a distillation range of 60 to 190 ° C, preferably 90 to 190 ° C, and to distill off the lighter hydrocarbons at 80 to 90 ° C with the top of the column, 160 to 170 ° C at the bottom of the column at 15 to 25 kPa abs. and as the distillation residue a hydrocarbon fraction with a content of indenation of 20% by weight is obtained, which is optionally further rectified in a vacuum column, where the distillate is a narrow fraction with an indene content of about 70% and a distillation residue is aromatic C _{lo +} frakee. in the paint industry, resp. as a component of motor fuels. The indene fraction can be used to produce high-quality indene resins, eventually it can be used as a solvent or binder component in paints, rubber softener, etc.

The mode of operation and effect of the invention is apparent from the following example:

Processing of heavy pyrolysis gasoline to an indene fraction with a content of over 20% by weight. indene.

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The naphtha was separated by condensing the pyrolysis gas in a scrubber at 80 ° C at the bottom and 35 ° C at the head and a pressure of 0.038 MPa and mixing gasoline from the condensates of the pyrolysis gas compression to a pressure level of 0.95 MPa. in sharp mode.

Composition of heavy pyrolysis gasoline:

° 5

Cg to non-aromatics

Benzene

Toluene

Xylenes

Ethylbenzene

Styren

Cg aromatics (indene)

1.6 wt.

10.3

25.3 23.0 10.1

3.3

8.8

12.1 (2.1) 5.5

Operating conditions of BTX column

BTX column: pressure, kPa abs.

head temperature, ° C bottom ° C reflux ratio distillate: composition, wt

C ^ hydrocarbons Cg to Cg non-aromatics Benzene Toluene Xylenes Ethylbenzene Styrene

Cg aromatics (indene) residue: composition, wt.

Cg aromatics

- Indene 26.2

- indane 1,4

- 1,2,3, trimethylbenzene 3,7

164

0.95

1.7

11.2

27.4 25.0 11.0

3.6

9.6

10.5 (<0.1)

31.3 ^C 10+ ^hydrocarbon y 68.7 238 584

0.92 t of distillate and 0.08 t of indene fraction containing 26.2% by weight of indene were obtained by injection of heavy pyrolysis gasoline.

Claims (2)

The invention is described herein Process for indene pyrolysis products l / ikAVAh in which pyrolysis products are obtained, after separation of the pyrolysis oils, by condensation in a water scrubber at a pressure of 0.03 to 0.08 MPa, a temperature of 30 to 45 ° C at the head and 75 to 85 ° C at the bottom Heavy pyrolysis gasoline to which is optionally added pyrolysis gasoline obtained from pyrolysis gas compression condensates to a pressure of 0.5 to 1.2 MPa at a temperature of 35 to 45 ° C, characterized in that distillation at a pressure of 15 to 25 kPa abs. , at the top of the column at 80 to 90 ° C and at the bottom of the column 160 to 170 ° C, only heavy pyrolysis gasoline with a distillation range of 60 to 190 ° C, preferably 90 to 190 ° C, is subjected to distillation. the residue gives a fraction with an indene content exceeding 20% by weight · 238 584 2. The process according to claim 1, characterized in that the indene concentrate above 60% by weight is rectified for a longer period and the distillate is obtained as a distillation residue. and as the residue the aromatic Cjq + fraction obtained under vacuum and indene content fraction ·