SU1065392A1 - Process for purifying aromatic hydrocarbons from thiophene and unsaturated compounds - Google Patents

Abstract

A METHOD FOR CLEANING AROMATIC HYDROCARBONS FROM TIOPHENE AND UNLIMITED CONNECTIONS by adsorption at elevated temperature and pressure with natural clay of the type of montmorillonite, activated with an acid treatment, characterized in that, in order to improve the level of treatment, 15% of the schedule, 15% of the time of treatment, 15% of the time of treatment, 15% of the time of treatment, 15% of the time of treatment, 15% of the time of treatment, 15% of the time of treatment, 15% of the time of treatment, 15% of the time of treatment, 15% of the time of treatment, and 15% of the time of treatment will be applied. the adsorbent used montmorillonite TaiaHCKoro field, activated by treatment with 20-25% sulfuric acid for 5-6 hours. (L at SP oo with tvO

Description

The invention relates to methods for the purification of aromatic hydrocarbons, such as benzene and its fractions, from thiophene and non-direct compounds,

Known Methods for the purification of benzene and benzene fractions from sulfur-containing 5 Shih compounds and olefins by the method of activated hell:; orbium alumina, katnyh clay.

In foreign practice, clay attapulgis and 10-terranes are used for this purpose.

In the USSR, the process of purification of aromatic hydrocarbons from the terminal compounds from chemically activated bentonites f 5 of the Cherkasy, Sarigyuh and Dekan fields was developed. To purify the aromatic compounds from the limited compounds, use is made of the fourth layer of the Cherkassy deposit, after thermal activation at 190,200 s, and the Cherkassy bentonite, after chemical activation, with 5–10% sulfuric acid (Adsorbent A-4).

Adsorbent A-4 is effective in the process of purification of aromatic hydrocarbons from impurities of unsaturated compounds. Odiac data on the purification of thiophene with hydrocarbons is not given by C13.,.

Also known purification method;, aromatic hydrocarbons, from thiophene-unsaturated compounds and pu-. the fact of their two-stage adsorption by glia A-4M based on Cherkassy bentonite and NlCaX zeolite. Cleaning 35 is carried out at L b 0-2 and pressures of 16-20 atm G2 3.

The disadvantage of this method is the two-stage process and. use of an expensive adsorbent.

Also known option processing pyrocondensate to benzene. Pyrocondensite fractions typically contain about 0.02. May.% bound sulfur,. including thiofen. A pyrocondensate processing scheme to produce benzene. . includes high quality hydrotreating units of the benzene-toluene-xylene fraction (WTF fraction) on the alumino-cobalt-molybdenum (or ali nickel; livedenum) catalyst and contact purification of the benzene concentrate on bentonite clay, re-purification of the purified fraction and separation of the Goods-. benzene and recirculated non-invertebane toluene and xylenes.

At the first stage of hydrogenation processing, under mild conditions, the most unstable unsaturated hydrocarbons are hydrogenated under 60 conditions. At the second stage of hydrogeiization processing, the complete removal of sulfur compounds is carried out by exhaustive hydrogenolysis of organic sulfur compounds, including thiophene

The disadvantage of this method is its multistage.

A method is also known that allows benzene to be obtained with a residual thiophene content of 0.5-1 h per million (ppm), in which the purification involves two stages. On the first wire there is a clearing of thiophene by passing the raw material through aluminosilicate clay at 400,500 s, followed by reactification; on the second, the product that has undergone this purification comes in contact with a catalyst made of nickel or nickel sulphide at 300-450 ° C to remove sulfur compounds by hydrogenation of f4j.

This Purification Method produces a high purity hydrocarbon from thiophene. However, it differs from stage to stage purification. In addition, the purification of benzene in the same way is associated with significant costs for the purchase of expensive adsorbents. . ,

The closest to the invention to the technical essence of the achieved result is the method of purification of aromatic hydrocarbons from thiophene and unsaturated compounds by adsorption at elevated temperatures and pressure, for example at 200 C and 20 atm, according to which donnite clay can be used as an adsorbent. 36. Nikkaiit C) -36 is a natural, clay of the type of montmorillonite, activated by the treatment with kirlota (and the conditions for the activation of clay were not disclosed - vagots) B 1.

However, the known method is characterized by an insufficient degree of purification of aromatic hydrocarbons from thiophea at high (more than 10 p.p.t.) concentrations of the latter, as well as rapid poisoning of the adsorbate (within 6-10 months), which leads to additional production costs. In addition, Nikka | 1it. Q-36 to a high-quality product purchased abroad (230 rubles / ton).

The purpose of the invention is to increase the thiophene purification fee and reduce the cost of the process. ,

This goal is achieved by the fact that according to the method of purification of aromatic hydrocarbons from thiophene and non-solitary compounds by adsorption at elevated temperature and pressure 9, natural clay is used as an adsorbent. montmoril Lonite of the Tagansky deposit, ctKTivirovannuyu processing 20-25% sulfur sulfur dioxide for 5-6 hours

The process is preferably carried out at 1BO-190 ° C and a pressure of 20 atm ..

In the process of clay clay leaching of the octahedral cations {Fe, Mg and partly P1) and the replacement of a substantial part of the cations / exchange complex with A1, is the active center for the adsorption of thiophene with a high degree of preservation of the aluminum-oxygen layer of the structure of the montmorillonite. The purification process is carried out by passing a mixture of aromatic hydrocarbons, in particular, a benzene-toluene fraction {benzene: toluene, 95: S) in the liquid phase at 160-190 s and a pressure of 16-20 atm. These conditions are optimal for ensuring the most complete purification of aromatic hydrocarbons from impurities, thiophene and unsaturated compounds. At the same time, an increase in the temperature in these P1 units leads to an increase in the cleaning efficiency, which. allows a long time to maintain an equal degree of purification by increasing the temperature with measure. reduction of the adsorbent coefficient. I. However, with increasing temperature. Above, a decrease in the efficiency of clay cleaning due to the destruction of its structure begins. Conducting a cleaning process at a nyrse temperature of 160 ° C does not give the desired effect on thiophene cleaning. The temperature within the 160-i90 c is the optimum. Y Note. The crushed sample of the original tagansky place, the birthplace (horizon 14) is loaded into a round bottom flask containing 6 25% sulfuric acid solution jCMfecb boiled for 6 hours with constant stirring. Consumption pact of sulfuric acid in terms of 8% -. After this adsor-. the bent is separated from the solution and washed with distilled water until neutral by methyl orange. By . ray adsorbent dried to constant n. The weight of the weight is in the drying cabinet and sieved with the selection of a fraction of 0.2-0, b MM.,. Comparative characteristics of the compositions of adsorbents made of Taganskaya clay in the well-known (Nickelite Q-36) are given in Table. 1 As can be seen from the table. 1, the adsorbents niccanite pr-3b and A-4M differ sharply from the used adsorbent from Taganskaya clay in terms of the content of the exchange alkali (Al), I which causes the high activity of the Taganskaya. clay when cleaning from sulfur compounds. A steel adsorber with a diameter of 20 mm mounted on industrial type zag1 is pressed down into the following sequence: - .; 1. To prevent adsor ablation. Bent put crushed layer in the amount of 5 cm in the next sequence of Fractions: 4–8 mesh, 10–20 mesh, 20–30 mesh. 2, Place the proposed adsorbent in the amount of BOC. , 3, Above, quartz will be placed in the same quantities in layers in the slant sequence of fractions: 4-8. mesh, 10-20 mesh, 20-30 mesh. The system is flushed with nitrogen at a pressure of 1-2 kg / cm. The cleaning process is carried out under the following conditions; the size of the adsorbent grains is p, 2-0.5 mm ;. adsorbent volume 60 cm, layer height 19 cm, diameter 2 cm; operating mode: adsorption temperature 160-190s, pressure 16-20 atm, the rate of passage of the benzene fraction 40 ml / h. 4, The benzene-toluene fraction supplied to the purification has the following composition., Ab, wt%: bisphen 0.007; benzene 95.4; toluene 4, paraffin 0.005; ethylbenzene, 0.13. Bromine number 430. OOMA. Under similar conditions, the second adsorber is loaded with clay, niccanite 14-36. The benzene-toluene fraction passing through the adsorbent circuit is reacted and the concentration of aromatic hydrocarbons, as well as the residual content of thiophene and unsaturated compounds (bromine number) are determined in the distillate. The purification rates for the acid concentration of aromatic hydrocarbons from thiophene are given in table.2f. Indicators of the degree of purification over time of the activity of aromatic hydrocarbons from thiophene are given in table. 3. Thus, the optimal activation time of clay is 5-6 hours at a concentration of sulfuric acid of 20-25 wt.%, Since the clay of the Tagansk, activated under these conditions, provides a high degree of purification from thiophenia (when kept in the source of raw materials 10 RR.): against 75-85% by a known method. In Tables 4-6, the purification of aromatic hydrocarbons on Taganskaya clay activated with 25% sulfuric acid for 6 hours, depending on the content of impurities in the feedstock and the conditions of the adsorption purification, is compared with what is known. . The cleaning performance of thiophene, depending on the conditions of the cleaning and the content of thiophene in the feedstock (With a volume of feedstock per unit of adsorbent 10 vol / vol ;-) presented in Table. 4. Indicators of cleaning from tofu. depending on the quantity of the missed raw material (at and at a pressure of 20 atm) are given in Table. five.

Indicators of purification from unsaturated compounds (at a pressure of 20 atm) are presented in Table. 6

From the data presented in the tables, it can be seen that the degree of purification of the final product from unsaturated compounds by the proposed cnocoi6oM is at the level of the known, and purification from the powder. with its concentrations in raw materials of 10.70 and 150 pp. proceeds to absence, while with the known method the residual content of thiophene is 1.5-2; 10-1.5, and 40-60 р.рт. respectively.

The time of protective action (service life) of adsorbents for raw materials containing 20 p.r. thiophene is: for Nikkanit 6-36 60 hours, and for the adsorbent used in the proposed method, 150 hours, which makes it possible to lengthen the operation cycle of the adsorber 2.5 times.

Thus, the proposed spot for purification of aromatic hydrocarbons from unsaturated compounds and thiophene using activated clay of the Tagan deposit as an adsorbent has the following advantages: the degree of purification from thiophene increases, the cycle of the adsorber increases by 2.5 times due to an increase in the service life of the adsorbent. At the same time, the costs j for the production of benzene are reduced by using an adsorbent based on cheap raw material at {raw material (cost of nickelite C-36 is 230 rubles / ton, the cost of the proposed domestic clay is 4 rubles / ton) and increasing the service life of the adsorbent.

Table

12.3 0.5 1.6 0.5

73.5 79.9 9.2 0.8. 0.75 0.98

14.3 7.3 5.8 1.3

54

five

6

15

6

6 6 6

20

25

30 36

46.7 24.3

12

Table 2

0.37-0.40

thirty

, 33

40

33

0,22-0,24

70 50

0.20-0.21

98-100 48

0.15-0.17

98-100 40

0.1-0.09

60-70

I

0.12-0.23

75-85

Table 3

: T a b l and c a 4

Continued table. five

T a Oh l and c and 6

Claims (1)

METHOD FOR PURIFICATION OF AROMATIC HYDROCARBONS FROM THIOPHENE AND UNCERTAIN COMPOUNDS by adsorption at elevated temperature and pressure using natural clay such as montmorillonite activated by acid treatment as an adsorbent, characterized in that, in order to increase the degree of purification from thiophene and uricene. Montmorillonite of the Taganskoye deposit is used, activated by treatment with 20-25% sulfuric acid for 5-6 hours. SU „„ 1065392