A method of processing bottoms distillation of styrene

 

(57) Abstract:

The invention relates to the petrochemical industry and can be used in the production of styrene by dehydrogenation of ethylbenzene and dehydration of methylphenylcarbinol. In the proposed method processing lead thermal depolymerization bottoms distillation of styrene with steam in the presence of hydrogen-containing gas, having in its composition ethylene 0,4-3,0 and methane 1-4 wt. %. Such processing leads to an increase in the conversion of heavy products and the increase in the yield of low-boiling aromatic hydrocarbons. 9 table.

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

A known method for separating aromatic hydrocarbons from serosoderjaschei VAT, formed during the purification of styrene (U.S. patent N 3501545, CL 260-674). According to this method, after prior dilution with a solvent and filtering the bottoms of the distillation of styrene (KORS) from the inhibitor, the remaining distillation is subjected to Giprosintez hydrogen on the catalyst at a temperature of 250-800oC. this resin Cool, ethylbenzene. Volumetric hourly feed rate of the diluted resin varies from 0.1 to 10 h-1. As a catalyst of Giprosintez are the oxides of chromium, tungsten, vanadium, titanium, iron with various additives.

The disadvantages of the method are: the use in the process of hydrogenation of pure hydrogen, low mileage catalyst requiring frequent regeneration and congestion and, as a consequence, a significant consumption of power.

The closest in technical essence is a method of producing styrene from the bottoms of the distillation of styrene (Ed. St. Czechoslovakia N 172096, class C 07 C 15/10), according to which styrene is recovered from KORS by thermal depolymerization at temperatures 390-500oC in the presence of water vapor space velocity KORS 0,5-4,0 l/h Dilution KORS: water vapor is maintained in a weight ratio of from 1:0.5 to 1:5. The process is carried out in a steel column filled rings "process".

Due to thermal depolymerization receive an additional amount of styrene.

The disadvantage of this method is the low conversion of heavy products and small amounts of low-boiling aromatic hydrocarbons.

the automatic hydrocarbon processing bottoms distillation of styrene.

This goal is achieved by thermal depolymerization bottoms distillation of styrene with steam in the presence of hydrogen-containing gas, having in its composition ethylene and methane. As a component of the reaction Giprosintez used hydrogen-containing gas neskondensirovannyh gas - waste production of styrene by dehydrogenation of ethylbenzene, which has in its composition ethylene and methane.

Processing bottoms distillation of styrene is carried out in the reactor column type, filled with inert head.

Distillation residues, pre-diluted benzatropine faction to viscosity of 2.0 to 3.0 SDR, mixed with superheated steam and hydrogen-containing gas, having in its composition ethylene and methane and fed into the reactor. In the reactor at a temperature of 400-600oC as a result of depolymerization reactions, dealkylation, hydrogenation, alkylation, etc. are formed additionally low-boiling aromatic hydrocarbons: benzene, toluene, ethylbenzene, styrene. The reaction products are condensed. The hydrocarbon system and sent to the distillation of styrene and unreacted hydrogen-containing gas (neskondensirovannyh gas) is used as Topley is their 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. In the reactor, filled rings "process" serves 100 kg/h of bottoms distillation of styrene diluted benzatropine faction to viscosity of 2.5 SDRs.

The styrene content in the original COURSE is 35 wt.%. KORS before feeding into the reactor is mixed with steam in a ratio of 1:3 by weight. The temperature in the reactor 500oC. product Compositions at the inlet and outlet of the reactor, excluding the solvent shown in table. 1.

The yield of liquid products of the reaction is 90% of the original. Conversion of "heavy" in low-boiling hydrocarbons of 26.9% and an additional 100 kg KORS received 7.5 kg low-boiling aromatic hydrocarbons.

Example 2.

The process is conducted according to the proposed method. In the reactor, filled rings "process" serves 100 kg/h of bottoms distillation of styrene diluted benzatropine faction to viscosity of 2.6 SDR. The styrene content in the original COURSE is 35 wt.%. KORS before feeding into the reactor is mixed with water vapor in the ratio of 1:3 by weight. The overall supply is mixed in with the contains: hydrogen 30, ethylene 0.4, methane and 1.0 wt.%; the rest is carbon dioxide and other impurities. The temperature in the reactor 500oC. the Composition of liquid products on the inlet and outlet of the reactor, excluding diluent is shown in table. 2.

The yield of liquid products of the reaction is 92% of the original. Conversion of "heavy" in low-boiling hydrocarbons at 78.4% and an additional 100 kg KORS received 43 kg low-boiling aromatic hydrocarbons.

Example 3.

The process is conducted according to the proposed method. In the reactor, filled rings "process" serves 100 kg/h of bottoms distillation of styrene, diluted with benzene-toluene fraction to the viscosity of 2.8 SDR. The styrene content in the original COURSE is 35 wt.%. KORS before feeding into the reactor is mixed with steam in a ratio of 1:3 by weight. Total feed is mixed with hydrogen-rich recycle gas at a weight ratio of CORSE:hydrogen gas is 1:0,05. The 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 500oC. the Composition of liquid products on the inlet and outlet of the reactor, excluding diluent is shown in table. 3.

The yield of liquid products of the reaction is kg KORS received 46,2 kg low-boiling aromatic hydrocarbons.

Example 4.

The process is conducted as in example 3. The hydrogen-containing gas contains hydrogen 30,0, ethylene 2.0 and methane to 3.0 wt.%; the rest is carbon dioxide and other impurities. The temperature in the reactor 500oC. the Composition of liquid products on the inlet and outlet of the reactor, excluding diluent is shown in table. 4.

The yield of liquid products of the reaction is 93,5% of the original. Conversion of "heavy" in low-boiling hydrocarbons amounted to 82.8% of and additionally 100 kg KORS received 47,3 kg low-boiling aromatic hydrocarbons.

Example 5.

The process is conducted 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 500oC. the Composition of liquid products on the inlet and outlet of the reactor, excluding diluent is shown in table. 5.

The yield of liquid products of the reaction is 94.0% of the original. Conversion of "heavy" in low-boiling hydrocarbons to 79.7% and an additional 100 kg KORS received the 45.8 kg low-boiling aromatic hydrocarbons.

Example 6.

The process is conducted as in example 3. The hydrogen-containing gas contains hydrogen 30,0, ethylene 3.0 and methane to 4.0 wt.%; else the e from the reactor, excluding diluent is shown in table. 6.

The yield of liquid products of the reaction is 94,1% of the original. Conversion of "heavy" in low-boiling hydrocarbons accounted for 79.8% and an additional 100 kg KORS received 46,0 kg low-boiling aromatic hydrocarbons.

Example 7.

The process is conducted as in example 3. The hydrogen-containing gas contains hydrogen 30,0, ethylene 0.4 and methane to 4.0 wt.%; the rest is carbon dioxide and other impurities. The temperature in the reactor 500oC. the Composition of liquid products on the inlet and outlet of the reactor, excluding diluent is shown in table. 7.

The yield of liquid products of the reaction is 92.4% of the original. Conversion of "heavy" in low-boiling hydrocarbons amounted to 81.5% and an additional 100 kg KORS received 45,4 kg low-boiling aromatic hydrocarbons.

Example 8.

The process is conducted as in example 3. The hydrogen-containing gas contains hydrogen 30,0, ethylene 3.0 and methane to 1.0 wt.%; the rest is carbon dioxide and other impurities. The temperature in the reactor 500oC. the Composition of liquid products on the inlet and outlet of the reactor, excluding diluent is shown in table. 8.

The yield of liquid products of the reaction is 92.8% of the original. Conversion of "heavy" in low-boiling hydrocarbons amounted to 80.3 per cent and on the ECC carried out according to the proposed method. In the reactor, filled rings "process" serves 100 kg/h of bottoms distillation of styrene diluted benzatropine faction to viscosity of 2.6 SDR. The styrene content in the original COURSE is 35 wt.%. KORS before feeding into the reactor is mixed with steam in a ratio of 1:3 by weight. Total feed is mixed with hydrogen-rich recycle gas at a weight ratio of CORSE:hydrogen gas of 1:0,1. The hydrogen-containing gas contains hydrogen 36, ethylene 3.0 and methane to 4.0 wt.%; the rest is carbon dioxide and other impurities. The temperature in the reactor 500oC. the Composition of liquid products on the inlet and outlet of the reactor, excluding diluent is shown in table. 9.

The yield of liquid products of the reaction is 93.6% of the original. Conversion of "heavy" in low-boiling hydrocarbons was 83.0 per cent and an additional 100 kg KORS received 47,6 kg low-boiling aromatic hydrocarbons.

Allocated from the liquid products of styrene meets the requirements of GOST 10003-90.

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

A method of processing bottoms distillation of styrene thermal depot is composed of ethylene 0,4 - 3.0 and methane 1 to 4 wt.%.

 

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