DD132779B1 - PROCESS FOR THE PRODUCTION OF XYLOLES - Google Patents

Description

The invention relates to a process for the production of high-purity o- and high-purity p-xylene with high yield from charcoal reactor oil fractions having different co-aromatics concentrations and with different yields

Levels of aromatics in the C ₇ - Cq range and non - aromatics in the C _R - C _1n ranges

Characteristic of the known technical solutions

Of the industrially used Cn aromatics, 0- and ρ-xylene take precedence as petrolchmical primary products due to their connection to the production of pits and plasters. " The petrolohemische further processing places high demands on the purity of the individual C ₀ aromatics and requires the provision of the individuals in the quantity conditional on the amount of post-processing. According to the basic technological concept currently used in the world, o- and ρ-xylene are prepared from complex mixtures (e «B · reformates of

straight run gasoline fractions, fully refined liquid petroleum pyrolysis products, cycle oil catalytic and thermal cracking plants) by coupling a variety of process stages (MEYER, IM ·: Chem * Ind. XXV / Dec _e 1973, page 808). Biese technology is due to the large number of required process stages, in particular by the necessary for the preparation of non-aromatic xylene mixtures distillation and extraction equipment economically Pr Pail Pail that the complex mixtures used as raw materials eeformates with high flavor tengehalton and very low non-aromatic contents were Technological solutions described in more recent times, which allow the waiver of the extraction stage and thus have economic advantages (OS 2 032 458) (ΔΓΚΙ-NS, RS: Hydrocarbon Processing 49 (1970) 11, p 129).

On the other hand, if reformates with a high or broadly variable content of nonaromatics are available, the economic advantage achieved by dispensing with the extraction stage will be due to an additional distillation effort required to separate off the .alpha p - ^ / xxylene recovery cycle and in the isomerization CQ + - annoying aromatic compounds and by the resulting negative effects on the Isomerisierungsstiafe (heavy load by the feed with Einsatζprodukt in which o-xylene is already present in the thermodynamic s equilibrium concentration equilibrium) compensated ,

(KÖNIG, G .: petroleum and coal 26 (1973) 6, S ₀ 324; BERGER, CoVc: Hydrocarbon Processing 52 (1973) 9, S 173, OS 2 526 288)

Ef.Mormate with high Ъаѵз. Widely variable levels of non-cash aromatics are increasingly available when the modern reforming process (high severity) used to produce the reformates has become necessary for reasons of improving the use of raw materials in the raw materials sector high liquid yields (and associated long system life en) are operated with medium or low Reformierschärfe or when the use of conventional reformer (medium or low severity) sharp Reformingfahrweisen due to the associated Flussigproduktverluste or for technological reasons does not allow.

Object of the invention

The aim of the invention is ea _? an economic processing of reformates ₅ which have been generated in reforming units which operate at medium or low and high severity or о ITichtaroiiatcngehaltu have variable in the wide range to 0- / P- "xylene high purity to allow.

ι + -

Presentation of the essence of the invention

It is therefore an object to develop a process, ie when using hydrocarbon mixtures which, in addition to Cp aromatics, contain hydrocarbons with lower and higher C number in high or strongly variable concentration, the production of o- and p- High purity xylene allowed for an extra stage of firing and with reduced distillation overhead over known processes

The object of the invention is based on the idea of realizing a novel combination of process stages, wherein

- The gaseous reaction product from dom reactor of the reforming plant is freed by a novel partial condensation of high-boiling hydrocarbons;

- The hydrocarbon feed mixture (reformate) is released together with the liquid product of the isomerization of the Nieh co-aromatics in a distillate at location;

- The o-XyIo! obtained extraction over a withdrawn in the distillation stage side stream;

the separation process used for the p-xylene recovery is a crystallization or adsorption process;

-S

- In the Isomerisienrgsstufe a catalyst with excessive but over the entire duration in dependence ofzNiehtaromatenangebot by addition of basic nitrogen compounds variably influenced cleavage activity is used _s without the reduction of the catalyst deactivation an additional stability-demanding metal component is incorporated in the catalyst.

It has been found that by an energy-saving coupling of heat exchange with simultaneous partial condensation and subsequent gas-Elüssigkeits-separation of Eeaktoraustrittsproduktes and hydrocarbon absorption and partial condensation of the separated gas phase an energetically and segregation effective technology sur generating a xylene cut can be achieved. The xylene cut thus produced can thus be largely freed of higher-boiling hydrocarbons and fed to the oil extraction without the interposition of an extraction stage.

Surprisingly, it has been found that the ingredients of the Reformatbcnzine obtained by reforming and the liquid scraper of Isonierisierungsanlagen, dio using a known noble metal-containing catalyst j as required for the inclusion of Äthylbenzols in the isomerization works, are largely identical (Example 1) and differ depending on the formative sharpness in the Kon.sentrationen.

Accordingly, for the removal of the paraffinic components of the Eeformates and the Isoraerisates of the Cq aromatics is an analog separation task «

According to the invention, both separation tasks can be solved in the same column system. It has been found that, in the column, with the aim of separating the o- xylene or residual Gq ₊ - if a value corresponding parameter forms a concentration profile operates aromatics Sutnpffraktion and the generation of an egg ⁴ o- xylolabgereicherfcen overhead fraction " The position of the maxima or minima for o-xylene _f Cq ₊ aromatics and paraffins are separated from each other by a corresponding number of trays in the column (Example 2), whereby the removal of a o xololreichen and nonaroinates and Cq ₊ -aromatic depleted Seit en current fraction succeeds (Example 3).

By extracting a scission fraction, a product is available which, owing to its low paraffin and Cq + aromatics concentration and its high oxy-xylene content, is directly in a downstream column with an economic advantage of oxy-xylene with a purity of over 90 , 5 Ma, - ¹ JS o-xylene work up.

Thus, the prejudice of the art is that the use of ηichtaromatenrich Cg Aromatenkonsentrafcen for o ~ xylene recovery without prior conversion of the paraffinic hydrocarbons contained in the C-Z aiiibereich of 8 - 1O to hydrocarbons with a smaller C-number is not possible _? It has been found that the use of a re-free catalyst in the isomerization stage has proved particularly advantageous for reducing paraffinic hydrocarbons in the ρ - / o-xylene recovery cycle, as described, inter alia, in patent WP 103 885

and was described in WP 104 967. It was found that such a catalyst, in addition to its high isomerization activity 5, recognizable by the setting of the thermodynamic equilibria for the xylenes even at high raw material loadings, and its excellent selectivity, the ethylbenzene conversion, visible in the xylene yields _f has an exceptionally high activity for accelerating reactions for the hydrogenative cleavage of paraffinic hydrocarbons, wherein the selectivity and activity can be variably influenced by the addition of basic nitrogen compounds over the entire leaching period (Example 6). The use of such a catalyst allows the selective conversion of paraffinic KohlenwasGois Loffe, which in the range of co-aromatics cioden _? in б he Jno - mcrioierungssfcufe to compounds having 3 - ¹ 5 Kolilonr: toffa с OmeU ₀

In this case, the catalyst used has such properties that it does not undergo any impairment of the lifetime without additional damage of the metal components requiring a stabilization (Z "B" Re). Formed KohlsnwasserGtol'fe Mg (liquid gases) are in the Icomorierun downstream columns by distillation from the o ~ / ~ g- Xy Lol-G-ewinnung.ski'eislauf removable (Example G) ₈

The embodiment is explained with reference to PIg ₉ I:

The gaseous reaction product of a biorcine refinery plant is converted into a column after heat treatment and simultaneous partial condensation as GLis liquid

- s-

used, in which the gas phase is depleted by phase separation gas liquid, partial condensation and hydrocarbon absorption by means of liquid reformate gas largely from higher boiling hydrocarbons

The Plüssigphase including the loaded detergent is thus enriched in particular with higher-boiling hydrocarbons and separated after subsequent relaxation in a redistillation in a Cg + ~ poor overhead fraction and Cq + -rich sump mixture · The Cς + low-head fraction 1 is a liquid together with the reaction product 14 of the isomerization of a Distillation column I fed as feedstock 2 * In the column I, a low-Cn, paraffinnaphthenreicher, benzene, toluolhaltiger product stream 3 is generated, which z * B "the carburetor fuel product ion can be supplied.

The bottoms fraction 4, which contains the product stream 2 carried Co aromatics, Cq + - aromatics and paraffinic hydrocarbons having a C number of 7-9 is used in a further distillation unit II, the technological regime is adjusted so that a o xylene-depleted overhead fraction containing a substantial portion of the paraffins fed in 4, an o-xylene-enriched side fraction 6 and a Cq-t-aromatic rich bottoms fraction 7 containing small amounts of o-xylene and the remaining 4 paraffins added becomes. The sump fraction 7 may be used, for example, as a gasoline fuel component and / or as a solvent.

From the side fraction 6 is in a Supex'fraktionierung III, which consists of a conventional two-column system, the first column is designed for technical reasons as a split column

or designed under Nuirzung the described in WP 118 599 circuit as a single-column system with decrease of o-xylene as a side fraction, o-xylene high E unit produced.

The top products 5 and 8 are combined to stream 11, from which in a separation stage IV highly pure p-xylene 12 is obtained. The p-xylene, o-xylene-depleted, ethylbenzene and m-xylene-enriched stream 13 which contains most of the paraffins fed in via columns 4 and III is subjected to an isomerization unit V, which is reacted with a catalyst according to WP 103 885 and WP 104 967 in the parameter area

400 - 500 о C 1 H ₂ 10 - 20 at 6 : 1 - 1 A.

KW

1 - 3 v / vli

works, wherein the basic nitrogen compounds хит influencing the catalyst activity can be supplied to the liquid feed product 13 or the gas cycle.

The liquid product from the isomerization unit _? in which the xylolic monomers are largely in thermodynamic equilibrium, after mixing with 1 of the column I fed «

The technology according to the invention can be used with advantages in the construction of new plant complexes for o and p xylene production. It also has particular advantages in the intensification of existing aromatics plant η j, which today becomes a requirement throughout the world due to the increasing demand for aromatics.

The effects achieved with such a technology are:

Release of an extraction capacity equivalent to the level of Cg-aromatics production;

Release of the distillation capacity to separate the extracted Cg aromatics from benzene / toluene;

Use of the released distillation capita for the production of pure benzene or pure toluene;

- Reduction of technical equipment and energy consumption in the production of quality benzene and toluene while creating additional capacity reserves;

- Saving of distillation effort to produce the Cg - aromatics concentrate;

- Reduction of separation costs for the production of pure o-xylene;

- Increase of о / p xylo production

- -ΊΊ

Ingredients of liquid reaction products of gasoline reforming and Cg aromatic isomerization

Process

Reformieru-g

isomerization

Components Ma.-4

η-С

i-0 _t

E-C,

η »С,

i-C

2.9 0.8 3.0 0.3 3.7 0.6 1.8 2.0 2.4 0.1 4.8 0.2 0.6 1.1 3.8 _ 9.8 - ѴЭ 0.1 8.8 0.4 0.1 0.1 1.7 0.3

0.2

0.1

NA ge s NA NA I NA II

III

45.5 5.9 33.6 3.0 10.0 2.5 1.9 0.4

Cg - aromatics 28.5 9OpO Cq + - aromatics 5.5 2.2 benzene 2.0 0.4 toluene 18o5 1.5

NA ges »: sum of non-aromatic hydrocarbons · hydrogens

NA I: Boiling range 65 - 11O ⁰ C NA II: Boiling range 110 - 13O ⁰ C NA III: Boiling range 130 - 155 ° C

ввппеззвпв concentration professionals eggs ИЫоппеІ

2 technology using device syringes

- o-xylene - C3 +

- · - m-Xy / o /

- - p ~ xylene

concentration

Compilation of measured concentrations in the side stream K II (inlet K III) with variation of side discharge bottom layer, removal amount, contact ratio and bottom temperature (Ma ···

Zulauf krön- from N / A 1 4 FROM p-X m · , 0 oX 0 C 9 ⁺ to 1 7 0 Δ kill 0 X ei υ JU Ii σ U 0.7 , 0 17.0 39 14 0 ,8th 3.0 "о 20.0 37 19 7 , 0

, _ττ5 KSAZ MSAZ RV Ts NA AB pX mX oX · /. nr / h ./. C

1 4 18 12 2.04 276.9 1.5 8.7 15.0 36.5 29.5 8.4

2 Ю 12 1.96 275.6 0.9 5.6 9.7 24.0 29.0 30.6

3 14 12 1.86 279.0 1.0 8.0 15.8 35.8 29 _} 0 10.4

4 18 9 1.84 276.5 0.6 10.2 16.2 39.6 29.8 3.6

5 18 6 2.04 277.5 0.5 6.5 U, о 36.5 36.6 5.9

6 18 6 1.88 272.3 0.4 6.6 14.6 35.1 41.2 2.1

7 18 6 2.07 270.4 0.5 5.3 15.2 30, ή 44.2 4.4

8 18 6 2.09 274.3 0.2 6.1 13.2 33.8 42.5 h, 2

9 18 6 2.06 272.9 0.5 5.6 11.5 29.3 45.3 7 ₅ 8

10 18 21 2.57 271.6 1.0 10.1 15 * 9 39.3 30.1 3.6

Variation Seitenentnalimeboaenla @ 3 NR: 1,2,3

Variation removal quantity ЖР: 1,4,5,10

Variation Reckoning ratio KR: 6,9,10

Variation of bottom temperature NR: 7,8,9

-AS

Inlet concentrations for K HI / technology without side stream take-off K II

from 4: N / A FROM p-X m-X oX C ₉ + to 17 18 40 18 piel 0.5 19 20 45 23 1.0 By S

Selected parameters for the columns K II and K III (corresponding to feed concentrations

Example 3/1

parameter without SAZ marsh Konzen "O K II K III new techn Rewind Ratio occurred ion 0.5-1. with SAZ old te _e 1.5-2. on o-xylene , 0 9-10 2 , 0-3 ^ 0 12-14 10-20 5 -10 3-5

C o ο η s e η -

14,0ration 14.0-19.0 14.0-19.0 18-23 45-50

on o-xylene

Ъеі normal capacity

Ratio "top product

to sump product ¹¹

30-60: 1 20- / | 0: 1 3: 1 1.5: 1

Ex iel 5;

NA distribution of columns К II and К III for selected experimental points £

balance point II 0 - 8 ° n-Cg 1 ic ₉ nc _g 1-C ₁₀ Inlet K II X 0 , 06 0.24 1 , 27 0.21 0.02 Head K II X , 05 0.25 , 58 0.18 _ Swamp K II X , 18.b - 0 - 0.02 0.35 Side stream K X - - 0 16 0.36 0.07 Head K III. 1 30 0.60 " Swamp K 111.1 - - 0.15 0, /! 8 Head K III.2 - - - 0.18 OJ 18 Swamp K HK - - - 0.44

χ for two-column technology (with single-column operation side stream K III.1 as target product / "head K 111,2")

Example 6:

Influence of ammonia concentration in the recycle gas on the catalyst activity

TiHo - concentration ppm 50 150

Einsatsprodukt reaction product E ^ asatzprod. Evaluation product, components Ma · - ^

Mges »10.0 16.0 5.0 9.0

NA I - 10.5 - 6.1

HA II 6.0 5.0 2.9 2 _? 5

ΙΓΔ III 4.0 0.5 2.1 0.4

Gg aromatics 90.0 84.0 95.0 91j <

Cg-aromatics losses - 6.0 - 4.0 0 ^ aromatization

A3 26.0 16.0 25.0 17.0

p-X 9.0 20.0 8.5 19.5

m-X 55.0 44.4 58.5 44.5

о-X 10.0 19.6 8.0 19.0

16.0 5.0 10.5 «Я» 5.0 2.9 0.5 2.1 84.0 95.0 6.0 - 16.0 25.0 20.0 8.5 44.4 58.5 19.6 8.0

Component distribution (exemplary embodiment)

product flow

10 11 12 13 14

Ко тропеnten I IiA ge s. II UA III K ^T A aromatics  f-A cm ⁰ s С

Toluene Cq aromatic distribution

p-X in-X

O "TA.

45.5 20.2 60.0 3.2 3.6 0.9 0.5 1.2 0.3 0.4 3.3 - 3.8 5.9

33.6 13.8 50j7 - -

10.0 5.2 11.8 1, 8 2.2 -

- 3.0

- 2.0 - 2.3 2.5

1.9 1.1 - 1.4 1.4 0.9 0.5 1.2 0.3 0.4 1.3 - 1.5 0 _s 4 28.5 66.1 2.591.8 96.4 93.4 5.5 98.8 99.0 2 96.7 99.5 96.2 90.0

5 ₅ 5 3.7 - 5.0 - 5.7 94.0 - - 97.6 ~

2 _? 0 1,1 4,0 - -.-.-- 18,5 9,1 33,5 ~ - - - - - -

- 2.2

- 0,4

- 1.5

19.0 16.7 80.0 16.5 19.5 5.8 - 12.4 0.1 - 19.3 0.1 22.6 15.0

19.0 19.7 20.0 19.6 22.5 14.4 - 23.2 0.5 - 22.7 99 * 5 8.9 20.4

40.0 43.0 - 43 _r 0 48.8 43.9 17 _? 0 55.70.1 10 49.0 0.3 58.0 44.6

22.0 20.6 - 20.9 9 _r 2 35.9 83.0 8.7 99.0 90 9.0 0.1 10.5 20.0

Claims (2)

Inven tion claim occurred as well as with different proportions of aromatics in the Cr ₇ -C., - area and non-aromatics in the Cc-CiQ range, characterized in that the gaseous reaction product from the reactor of the reforming plant is largely freed by partial condensation of the high-boiling hydrocarbons and after complete Condensation as a Cg-aromatics containing raw material mixture together with the liquid product of the isomerization in a first distillation column downstream of the isomerization in a Со-aromatomatenarme, paraffin-. naph ^! benzene- and toluene-rich overhead fraction and every C 2+ -aromatic-containing C ₈ -aromatic rich bottoms fraction is decomposed, which in a second distillation column into an ethylbenzene, p-xylene and m-xylene rich head fraction, one in the region of the o -Xylo! Concentration-maximized side face ion and a substantially Cg + aromatics Su ^ pffraktion is separated, wherein the top fraction for separating high-purity p-xylene is fed to a separation step and thereby generated o- ₅ p- хуіоіагтз, ethylbenzene, m -xylo! rich co-aromatics fraction in an isomerization stage παν generation dec loomcricates with a wide range of introduced C "cleavage, which is converted to and from the o-ocylolane species Side fraction in a further distillation unit high purity o-xylene is obtained, the resulting o-xylolarme Cg-aromatic mixture is fed back to the o-, p-xylene recovery cycle, 2, Method according to item 1, characterized in that in the second distillation column, the parameters are set so that above the column concentration profiles with maxima or minima for o-xylene, Cη + -Aro maten form and non-aromatic, wherein the Maximum of o-Xylolkonzentrafcioa of the maximum of Cg + ~ aromatics concentration separated by a corresponding number of soils and sie the minimum of the ITichtaromatenkonzentration with the maximum of the o-xylene concentration superimposed. Missing after items 1 and 2 _S characterized in that in the Isoinerisierungaotufe a Re-free catalyst is used, in addition to the setting of theiiiodynamiöchcn equilibrium for the Xylolisorr.ercn in Gleichseitiger inclusion of Äthylbenzola in the isomerization on an excessive activity for the conversion of paraffinic KohlenwasserstоГГо through hydrolytic cleavage, wherein the solubility of the cleavage is variably influenced by the addition of basic nitrogen compounds See .. Ί _Seiicn Zeidinungon