RU2121473C1 - Method of processing stillage residues of styrene rectification - Google Patents

Abstract

FIELD: petrochemical industry, more particularly manufacture of styrene by dehydrogenation of ethylbenzene and dehydration of methylphenyl carbinol. SUBSTANCE: processing is carried out by thermal depolymerization of stillage residue of styrene rectification using steam in the presence of hydrogen containing gas which contains 0.4-3.0 wt % ethylene and 1.4 wt % methane. Such processing leads to greater conversion of "heavy" products and increased yield of low-boiling aromatic hydrocarbons. EFFECT: more efficient processing method. 1 dwg, 9 ex, 9 tbl

Description

 The invention relates to the petrochemical industry and can be used in the production of styrene by the dehydrogenation of ethylbenzene and the dehydration of methylphenylcarbinol.

A known method for the separation of aromatic hydrocarbons from sulfur-containing vat formed during the cleaning of styrene (US patent N 3501545, CL 260-674). According to this method, after preliminary dilution with a solvent and filtration of styrene distillation distillation residues (KORS) from the inhibitor, the remaining bottoms are hydrogen synthesized on a catalyst at a temperature of 250-800 ^o C. In this case, KORS resins turn into low-boiling (boiling points below 250 ^o C) aromatic hydrocarbons - benzene, toluene, ethylbenzene. The volumetric hourly feed rate of the diluted resin varies from 0.1 to 10 h ^-1 . Oxides of chromium, tungsten, vanadium, titanium, and iron with various additives are used as a catalyst for hydrosynthesis.

 The disadvantages of the method are: the use of pure hydrogen in the hydrogenation process, the low range of the catalyst and the need for its frequent regeneration and overload and, as a result, a significant consumption of energy.

The closest in its technical essence is a method for producing styrene from distillation residues of styrene rectification (Aut. St. Czechoslovakia N 172096, class C 07 C 15/10), according to which styrene is isolated from KORS by thermal depolymerization at a temperature of 390-500 ^o C the presence of water vapor volumetric feed rate KORS 0.5-4.0 l / h Dilution of KORS: water vapor is maintained in a weight ratio of 1: 0.5 to 1: 5. The process is carried out in a steel column filled with Rashiga rings.

 Due to thermal depolymerization, an additional amount of styrene is obtained.

 The disadvantage of this method is the low conversion of "heavy" products and a small amount of low boiling aromatic hydrocarbons.

 The aim of the invention is to increase the conversion of "heavy" products and increase the yield of low-boiling aromatic hydrocarbons in the processing of distillation residues of styrene rectification.

 The goal - is achieved by thermal depolymerization of distillation distillation residues of styrene with steam in the presence of a hydrogen-containing gas containing ethylene and methane. As a component of the hydrosynthesis reaction, a hydrogen-containing gas is used - non-condensed gas - a waste of styrene production by dehydrogenation of ethylbenzene, which contains ethylene and methane.

 The processing of bottoms of styrene rectification is carried out in a column type reactor filled with an inert nozzle.

Vat residues, previously diluted with a benzene-toluene fraction to a viscosity of 2.0-3.0 cps, are mixed with superheated water vapor and a hydrogen-containing gas containing ethylene and methane and fed to the reactor. In the reactor at a temperature of 400-600 ^o C as a result of reactions of depolymerization, dealkylation, hydrogenation, alkylation, etc. additional low-boiling aromatic hydrocarbons are formed: benzene, toluene, ethylbenzene, styrene. The reaction products condense. Hydrocarbons are sent to the styrene rectification system, and unreacted hydrogen-containing gas (non-condensed gas) is used as fuel.

 The use of the invention will reduce the amount of production waste, increase the yield of low boiling aromatic hydrocarbons and reduce the specific consumption of raw materials.

 The invention is illustrated by the following examples.

 Example 1 (comparative).

 The process is carried out according to a known method. 100 kg / h of bottoms of styrene rectification diluted with benzene-toluene fraction to a viscosity of 2.5 cps are fed into a reactor filled with Rashiga rings.

The styrene content in the original KORS is 35 wt.%. KORS before being fed into the reactor is mixed with steam in a ratio of 1: 3 by weight. The temperature in the reactor is 500 ^o C. The compositions of the products at the inlet and outlet of the reactor without solvent are shown in table. 1.

 The yield of liquid reaction products is 90% of the original. The conversion of “heavy” to low-boiling hydrocarbons was 26.9% and an additional 7.5 kg of low-boiling aromatic hydrocarbons were obtained per 100 kg of KORS.

 Example 2

The process is carried out according to the proposed method. 100 kg / h of bottoms of styrene rectification diluted with benzene-toluene fraction to a viscosity of 2.6 cps are fed into a reactor filled with Rashiga rings. The styrene content in the original KORS is 35 wt.%. KORS before feeding into the reactor is mixed with steam in a ratio of 1: 3 by weight. The total supply is mixed with hydrogen-containing gas at a weight ratio of KORS: hydrogen-containing gas equal to 1: 0.05. Hydrogen-containing gas contains: hydrogen 30, ethylene 0.4, methane 1.0 wt.%; the rest is carbon dioxide and other impurities. The temperature in the reactor is 500 ^o C. The compositions of the liquid products at the inlet and outlet of the reactor excluding diluent are given in table. 2.

 The yield of liquid reaction products is 92% of the original. The conversion of “heavy” to low-boiling hydrocarbons was 78.4%, and an additional 100 kg of KORS produced 43 kg of low-boiling aromatic hydrocarbons.

 Example 3

The process is carried out according to the proposed method. 100 kg / h of bottoms of rectification of styrene diluted with benzene-toluene fraction to a viscosity of 2.8 cps are fed into a reactor filled with Rashiga rings. The styrene content in the original KORS is 35 wt.%. KORS before being fed into the reactor is mixed with steam in a ratio of 1: 3 by weight. The total supply is mixed with hydrogen-containing gas at a weight ratio of KORS: hydrogen-containing gas equal to 1: 0.05. Hydrogen-containing gas contains: hydrogen 30.0, ethylene 1.0 and methane 2.0 wt.%; the rest is carbon dioxide and other impurities. The temperature in the reactor is 500 ^o C. The compositions of the liquid products at the inlet and outlet of the reactor excluding diluent are given in table. 3.

 The yield of liquid reaction products is 93% of the original. The conversion of “heavy” to low boiling hydrocarbons was 81.8%, and an additional 100 kg of KORS received 46.2 kg of low boiling aromatic hydrocarbons.

 Example 4

The process is carried out as in example 3. The hydrogen-containing gas contains: hydrogen 30.0, ethylene 2.0 and methane 3.0 wt.%; the rest is carbon dioxide and other impurities. The temperature in the reactor is 500 ^o C. The compositions of the liquid products at the inlet and outlet of the reactor excluding diluent are given in table. 4.

 The yield of liquid reaction products is 93.5% of the original. The conversion of “heavy” to low-boiling hydrocarbons was 82.8% and an additional 100 kg of KORS yielded 47.3 kg of low-boiling aromatic hydrocarbons.

 Example 5

The process is carried out as in example 3. The hydrogen-containing gas contains: hydrogen 30.0, ethylene 2.5 and methane 3.5 wt.%; the rest is carbon dioxide and other impurities. The temperature in the reactor is 500 ^o C. The compositions of the liquid products at the inlet and outlet of the reactor excluding diluent are given in table. 5.

 The yield of liquid reaction products is 94.0% of the original. The conversion of “heavy” to low-boiling hydrocarbons was 79.7%, and an additional 100 kg of KORS produced 45.8 kg of low-boiling aromatic hydrocarbons.

 Example 6

The process is carried out as in example 3. The hydrogen-containing gas contains: hydrogen 30.0, ethylene 3.0 and methane 4.0 wt.%; the rest is carbon dioxide and other impurities. The temperature in the reactor is 500 ^o C. The compositions of the liquid products at the inlet and outlet of the reactor excluding diluent are given in table. 6.

 The yield of liquid reaction products is 94.1% of the original. The conversion of “heavy” to low-boiling hydrocarbons was 79.8%, and an additional 100 kg of KORS received 46.0 kg of low-boiling aromatic hydrocarbons.

 Example 7

The process is carried out as in example 3. The hydrogen-containing gas contains: hydrogen 30.0, ethylene 0.4 and methane 4.0 wt.%; the rest is carbon dioxide and other impurities. The temperature in the reactor is 500 ^o C. The compositions of the liquid products at the inlet and outlet of the reactor excluding diluent are given in table. 7.

 The yield of liquid reaction products is 92.4% of the original. The conversion of “heavy” to low boiling hydrocarbons was 81.5%, and an additional 100.4 kg of KORS produced 45.4 kg of low boiling aromatic hydrocarbons.

 Example 8

The process is carried out as in example 3. Hydrogen-containing gas contains: hydrogen 30.0, ethylene 3.0 and methane 1.0 wt.%; the rest is carbon dioxide and other impurities. The temperature in the reactor is 500 ^o C. The compositions of the liquid products at the inlet and outlet of the reactor excluding diluent are given in table. eight.

 The yield of liquid reaction products is 92.8% of the original. The conversion of “heavy” to low-boiling hydrocarbons was 80.3%, and an additional 100 kg of KORS obtained 45.0 kg of low-boiling aromatic hydrocarbons.

Example 9. The process is carried out according to the proposed method. 100 kg / h of bottoms of styrene rectification diluted with benzene-toluene fraction to a viscosity of 2.6 cps are fed into a reactor filled with Rashiga rings. The styrene content in the original KORS is 35 wt.%. KORS before being fed into the reactor is mixed with steam in a ratio of 1: 3 by weight. The total supply is mixed with a hydrogen-containing gas at a weight ratio of KORS: hydrogen-containing gas equal to 1: 0.1. Hydrogen-containing gas contains: hydrogen 36, ethylene 3.0 and methane 4.0 wt.%; the rest is carbon dioxide and other impurities. The temperature in the reactor is 500 ^o C. The compositions of the liquid products at the inlet and outlet of the reactor excluding diluent are given in table. nine.

 The yield of liquid reaction products is 93.6% of the original. The conversion of “heavy” to low boiling hydrocarbons was 83.0%, and an additional 100 kg of KORS produced 47.6 kg of low boiling aromatic hydrocarbons.

 Styrene released from liquid products meets the requirements of GOST 10003-90.

 Low boilers - benzene, toluene, ethylbenzene - are used to synthesize styrene through appropriate syntheses, reducing the specific consumption of raw materials.

Claims (1)

 A method of processing bottoms of styrene rectification by thermal depolymerization with water vapor, characterized in that the processing is carried out in the presence of a hydrogen-containing gas having ethylene 0.4-3.0 and methane 1-4 wt.%.

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