SU1705270A1 - Method of cleaning benzene from thiophene and acetone - Google Patents

Abstract

The invention relates to petrochemistry, in particular the purification of benzene from thiophene and acetone. The purpose of the invention is to reduce the cost and simplify the process. The process is conducted by contacting benzene with an adsorbent — a crumb of a cracking catalyst based on a zeolite of type U containing rare-earth elements. - Tseokar ZM, at 25-30 ° C; C, atmospheric pressure and flow rate of benzene 0.5-1. These conditions provide a thiophene recovery rate of up to 100% under gentle conditions for temperature and pressure against 160-190 ° C. With and pressure of 16-20 MPa in a known case. 1 tab.

Description

The invention relates to petrochemistry, in particular, to a method of purifying benzene from thiophene and acetone, and can be used in those petrochemical industry where highly purified benzene is used as a raw material, for example, in the alkylation of benzene with propylene, ethylene or other olefins in the presence of a catalyst of aluminum chloride or in the process of hydrogenation of benzene to cyclohexane. The presence of these impurities in benzene leads to an increase in the consumption of catalyst and raw materials in various technological processes.

The industrial continuous process of the sulfuric acid purification of benzene from thiophene and other sulfur compounds is known, which is based on the alkylation of thiophene with unsaturated compounds by the catalytic action of sulfuric acid.

concentrations of 93-94%. The process is carried out in the liquid phase in two steps, with mandatory neutralization and stripping of benzene from the reaction products after each step.

Also known is the vapor-phase method of sulfuric acid purification from thiophene, in which 84–87% sulfuric acid is used.

Disadvantages of sulfuric acid purification of benzene from thiophene: environmental pollution; severe sanitary and hygienic working conditions at facilities; equipment corrosion; significant loss of benzene and reagents; high energy consumption for benzene vaporization in the vapor phase method.

The closest in technical essence to the present invention is a method for purifying aromatic hydrocarbons from thiophene and unsaturated compounds by

3

YU

3

adsorption using as a adsorbent natural clay, activated by treatment with sulfuric acid. The process is carried out at 160-190 ° C. Pressure 1.6-2.0 MPa.

However, the data on the purification from oxygen-containing compounds, in particular from acetone, are not presented in the known method.

The most significant disadvantage of this method is the high temperature and pressure of the cleaning process, which complicates the process flow diagram and increases energy consumption.

The purpose of the invention is to reduce the cost and simplify the process while ensuring a high degree of purification from thiophene. and also cleaning from acetone to its absence.

The goal is achieved by the fact that according to the method of purification of benzene from thiophene by contacting with the adsorbent, a cracking catalyst based on zeolite of the type U containing rare earth elements, Tseokar ZM (PG 38.40169-87), which is a waste of catalyst production, and The process is carried out at 25-30 ° C with a bulk feed rate of 0.5-1.0 h 1 at atmospheric pressure.

The proposed method differs in that. that the previously unused adsorbent is used to purify benzene — the said catalyst crumb, which allows, at lower temperatures and pressures, simultaneously remove impurities of oxygen-containing compounds, in particular acetone, simultaneously with thiophene.

The essence of the proposed method is as follows.

Benzene is fed to the adsorber, where it passes through the layer of adsorbent. The impurities of thiophene and acetone are adsorbed on the adsorbent, and the purified benzene is removed from the adsorber and collected in a collector.

At the end of the adsorption stage, the feed is stopped and the non-adsorbed product is drained under nitrogen pressure from the bottom of the adsorber to a trap.

The nitrogen is stripped of thiophene and acetone and other absorbed impurities. Desorbate collected in the trap.

In the case of a decrease in the activity of the adsorbent, oxidative regeneration is carried out.

In the proposed benzene purification process, adsorption is carried out under the following conditions: temperature 25-30 ° C; pressure is atmospheric; stage duration

adsorption 16.2-2.0 hours; benzene flow rate 0.5-1.0 h,

The desorption of the absorbed impurities is carried out by purging with nitrogen at 180–200 ° C.

The nitrogen feed rate is 3-5 hours (for gas). The adsorbent is regenerated in air flow at 550 ° C.

The expected lifetime of the adsorbent is 6 months.

At the end of the experiment, the purified benzene is analyzed by chromatography. From the content of thiophene and acetone in the purified product, the degree of extraction of impurities is calculated.

This temperature range (25-30 ° C) is based on the storage conditions of benzene in the raw material park, from where it can be directly sent for cleaning without additional energy costs.

Carrying out the process with a volumetric feed rate of less than 0.5 leads to a significant decrease in the capacity of the plant, and an increase in the feed rate of the feed is

1.0 - to a rapid decrease in the dynamic adsorption capacity of the catalyst crumb, and, consequently, to its inefficient operation.

PRI me R 1. Raw materials - benzene coal with a content of thiophene .0.0037 wt.% And acetone 0,000138 wt.%.

The volume of the loaded adsorbent is 80 cm. the height of the adsorbent layer is 34 cm, the diameter of the adsorbent is 1.9 cm.

Adsorption conditions: temperature 30 ° C; bulk feed rate of 0.5 h 1; pressure is atmospheric.

In purified benzene, thiophene and acetone are absent (the degree of extraction of both impurities is 100%).

PRI mme R 2. Raw materials - coal benzene containing thiophene 0,0115 wt.% And acetone 0,00148 wt.%.

The volume of the loaded adsorbent is 120 cm3, the height of the layer of the adsorbent is 51 cm, the diameter of the adsorbent is 1.9 cm.

Adsorption conditions: temperature 25 ° C; volumetric feed rate of 1.0 h 1; pressure is atmospheric,

In purified benzene, the thiophene content is 0.00078 wt.% (The recovery degree is 88.2%), acetone is absent (the recovery degree is 100%).

Example Raw materials - coal benzene with thiophene content of 0.0251 wt.% And acetone - 0.0053 wt.%.

The volume of the loaded adsorbent 170 cm3. The height of the layer of the adsorbent is 35 cm, the diameter of the adsorbent is 2.5 cm.

Adsorption conditions: temperature 30 ° C; volumetric feed rate of 1.0 pressure - atmospheric.

In purified benzene, the content of thiophene is 0.0031 wt.% (Extraction degree 87.6%), acetone is absent (recovery degree 100%).

Comparative results of benzene purification are shown in the table.

0

Claims (1)

Claims The method of purifying benzene from thiophene and acetone by contacting with an adsorbent, characterized in that, in order to reduce the cost and simplify the process, crumbing of a cracking catalyst based on zeolite of the type U. containing rare-earth elements is used as the adsorbent, and Ceocar ZM, and the process wire t at a temperature of 25-30 ° C and a bulk feed rate of 0.5-1.0 h of pressure. -one at atmospheric The proposed method Coal-benzene raw material with a content of 0.037-0.025 May. % thiophene; 0.000253-0.0025 mas.% Acetone Adsorbent Catalyst crumbs Tseokar ZM. The volume of adsorbent 80-170 cm3 Adsorption conditions: Temperature 25-30 ° C Pressure- atm. Bulk feed rate 40-170 ml / h Extraction: 87.6-100% thiophene acetone 100% Known method The raw material is a benzoltoluene fraction, with a thiophene content of 0.0005-0.015 May. %; acetone is absent Adsorbent Natural clay type montmorillonite, activated by treatment with 20-25% sulfuric acid. The volume of the adsorbent is 60 cm3. Adsorption conditions: Temperature 160-190 ° С Pressure is 16-20 MPa. Bulk feed rate-40 l / h Extraction rate thiophene 98-100%