Method for isolation of aromatic hydrocarbon from noncondensed gases in manufacturing styrene

FIELD: chemistry of aromatic compounds, petroleum chemistry, chemical technology.

SUBSTANCE: method involves carrying out three-stage isolation of aromatic hydrocarbons by separation, absorption and separation using at absorption stage atmosphere distillate off (TS 38.401194-92) as absorbent and prepared in manufacturing oil-polymeric resin by catalytic method. Invention provides reducing loss of aromatic hydrocarbons and improving economic indices of process in manufacturing styrene.

EFFECT: improved method for isolation.

1 tbl, 2 dwg, 5 ex

 

The present invention relates to the production of styrene, in particular to the method of separation of aromatic hydrocarbons from nscontainerbox gases for styrene, and can be used in the petrochemical industry in the production of styrene and other aromatic hydrocarbons.

The known method (ed. St. USSR №1168545, class C 07 C 15/46, 1985) release of aromatic hydrocarbons from nscontainerbox gases, which as absorbent use the distillation residues of the distillation of styrene, when the high viscosity of the absorbent requires the introduction of a diluent and, as a consequence, the additional energy consumption by Stripping and distillation products absorption.

The known method (U.S. Pat. U.S. No. 4288234, CL 01 D 47/00, 1981) selection of aromatic hydrocarbons from nscontainerbox gases of the catalytic dehydrogenation of ethylbenzene by means of absorption neskondensirovannyh gas. Removals are heavy by-products of the production of ethylbenzene containing diphenylethan and polyalkylbenzene, including o-m-p-diethylbenzene at a temperature 17-52°and a pressure of 1-8 ATA. Desorption of aromatic hydrocarbons from saturated technical absorbents provide steam at a temperature of 52-149°and the pressure of 0.07 to 2.8 ATA. According to this method, the volume fraction remaining in neskondensirovannyh g is ze aromatic hydrocarbons is 0.2%.

The known method has the following disadvantages.

High residual content of aromatic hydrocarbons in neskondensirovannyh gas, used as an absorbent for processing exhaust gases polyalkylbenzenes resin containing o-m-p-diethylbenzene that requires thorough cleaning released by desorption of aromatic hydrocarbons. Desorbed aromatic hydrocarbons containing diethylbenzene enter the system for the allocation of styrene, where return ethylbenzene sent to the dehydrogenation, where from diethylbenzene formed divinylbenzene, causing intensive driving cross-linked polymer, which reduces plant productivity and leads to losses of the target product. In addition, desorption of aromatic hydrocarbons from saturated heavy absorbent as under vacuum and at a pressure in the desorption column requires greater consumption of power.

The closest in technical essence and the achieved result of the present invention is a method for separating aromatic hydrocarbons from neskondensirovannyh gases styrene production (Patent RF №2063950, class C 07 C 15/46, 7/11, 20.07.1996). The method provides for the separation of aromatic hydrocarbons from neskondensirovannyh gases styrene production in three stages. Perva the stage the preliminary allocation of aromatic hydrocarbons separation. The second stage is the absorption of aromatic hydrocarbons, etilbenzene charge. The third separation unabsorbed gas drop entrainment.

Absorbent - ethylbenzene mixture is a mixture of direct and return ethylbenzene, with a mass fraction, %: benzene 0,1; toluene 0,8; ethylbenzene 98,6; styrene of 0.5. The rich absorbent is again applied to the dehydrogenation of ethylbenzene to styrene.

According to prototype selection aromatic hydrocarbons is carried out by the scheme (Figure 1).

Neskondensirovannyh gas, volume fraction of aromatic hydrocarbons in which a 1.46-3,80%coming from the Department of condensing gas contact process for the catalytic dehydrogenation of ethyl benzene from line 1 enters the drop entrainment 2, where at a temperature of 1-5°and pressure of 1,2-5,0 ATA allocated mechanically gone hydrocarbons and water. Speed tangentially introduced into the drop entrainment on line 1 gas flow of 50 m/S. the Use of drop entrainment can reduce the content of aromatic hydrocarbons and water, and thereby to reduce the load on the stage of absorption.

Neskondensirovannyh gas of drop entrainment 2 line 5 enters the absorber 6, where line 7 is absorbent. As an absorbent is used, ethylbenzene mixture is a mixture of straight run and who the military benzene, containing a mass fraction, %: benzene - 0,1; toluene - 0,8; ethylbenzene - 98,6; styrene and 0.5. The absorption process is carried out at a temperature of minus 10 - +1°and a pressure of 1.2-5 ATA. Speed neskondensirovannyh gas on the free section of 0.22 m/s, density of coverage not less than 5 m3/m2including the Rich absorbent from the absorber 6 through line 8 flows into the collector 4.

Neskondensirovannyh gas containing no water from the absorber 6 through line 9 is sent to the drop entrainment 10, at a temperature of minus 10 to minus 15°and pressure of 1,2 - 5,0 ATA additionally allocated hydrocarbons. Speed tangentially introduced into the drop entrainment on line 9 flow neskondensirovannyh gas 50 m/s, the drop entrainment equipped agglomerated device.

After the selection in the drop entrainment 10 volume fraction of aromatic hydrocarbons in neskondensirovannyh gas in line 12 is 0,008%.

Nscontainerframe hydrocarbons from the drop entrainment 10 through line 12 is directed or burning is used as fuel, or for generation of hydrogen gas. Selected hydrocarbons from the drop entrainment 10 line 11 enter the collector 4. Aromatic hydrocarbons with water from collector 4 through line 13 serves as a component of raw materials, in the dehydrogenation of ethylbenzene.

The disadvantages of this method are:

1. Use as absorbent ethylbenzol the th mixture, which is then used for the dehydrogenation of ethylbenzene to styrene. According to the requirements on the purity of the raw material for the process of dehydrogenation of ethylbenzene to styrene (GOST 9385-77) is highly regulated mass fraction of benzene at least 99.8% and the content of the styrene - absence. The reduction of the amount of ethylbenzene in the feedstock leads to deterioration of the selectivity of formation of styrene.

2. In the presence of styrene in raw materials for the dehydrogenation under the influence of high temperature non-catalytic reaction zones by free-radical mechanism is the formation of impurities which adversely affect the quality of commercial styrene:

The aim of the invention is to reduce losses of aromatic hydrocarbons, the improvement of technical and economic indicators of the production of styrene by increasing the selectivity of the target response and avoiding contamination of the raw materials dehydrogenation products of side reactions that adversely affect the catalyst and the properties of the commodity styrene. At the same time, highlighted in the process of absorption of aromatic hydrocarbons are used as a valuable component of the raw material in the production process, petroleum resin catalytic method.

This objective is achieved in that the aromatic coal the hydrogens are allocated from nscontainerbox gases styrene production in three stages: separation; absorption and separation, and as absorbent under absorption uses atmospheric distillation on THE 38.401194 - 92, obtained in the production of petroleum resin catalytic method and hydrocarbon having the following composition, mass fraction of component, %:

pentadien0,13-0,24
the cyclopentadiene0,04-0,10
benzene0,05-0,20
toluene0,21-0,64
ethylbenzenefor 0,19 0,39
p-xylene0,04-0,07
m-xylene0,18-0,34
o-xylene0,85-1,46
isopropylbenzene1,38-1,74
styrenethe 4.65-6,41
the amount of ethyltoluene7,88-10,02
the Dicyclopentadiene3,44-was 4.02
the amount of mesitylene and tertbutylbenzenewas 2.76-3,54
pseudocolor15,34-17,77
alpha methylsterolto 9.91-12,16
p-diethylbenzene2,61-4,08
the amount of m-diethylbenzene and Indiana6,67-being 9.61
o-diethylbenzene5,95-6,99
indenbecomes 9.97-15,39
d the rol 0,27-0,73
naphthalene1,76-of 4.38
the amount of unidentifiedto 11.11-15,21

Comparative analysis of the proposed method with the prototype allows to conclude that the claimed method differs from the known use as an absorbent for absorption of aromatic hydrocarbons from nscontainerbox gases styrene production of atmospheric distillate obtained in the production of petroleum resin catalytic method.

Analysis of the known methods of extraction of aromatic hydrocarbons from nscontainerbox gases styrene production showed that the method of separation of aromatic hydrocarbons from nscontainerbox gas production of styrene, which includes three stages: separation, absorption and separation are known. Known facts and use as absorbents, recirculating in the process of obtaining styrene, etilbenzene charge and heavy by-products production of ethylbenzene containing diphenylethan and polyalkylbenzene. However, only the fact that the use as absorbent atmospheric distillate obtained in the production of petroleum resin catalytic method allows deep to extract aromatic hydrocarbons and clean nscontainerframe gases styrene production. the using atmospheric distillation (TU 38.401194 - 92), which after absorption is used in the production of petroleum resin, and not etilbenzene mixture of raw materials to receipt of styrene, at the same time lets not degrade the properties of the target product is styrene.

The essence of the method consists in the following.

Selection of aromatic hydrocarbons is carried out according to the following schematic (Figure 2).

Neskondensirovannyh the gas separation dehydrogenation of ethylbenzene after condensation from line 1 enters the drop entrainment 2, from which liquid aromatic hydrocarbons and water lines 3 are merged into the collector 4. Separation of hydrocarbons and water in the drop entrainment 2 is carried out at a temperature of 1-5°and pressure of 1,2-5,0 ATA. The use of drop entrainment can reduce the content of aromatic hydrocarbons and water in the stream arriving at the stage of absorption.

Neskondensirovannyh gas of drop entrainment 2 line 5 enters the absorber 6, where line 7 is absorbent. As absorbent under absorption uses atmospheric distillate obtained in the production of petroleum resin catalytic method and hydrocarbon having the following composition, mass fraction of component, %:

pentadien0,13-0,24
the cyclopentadiene0,04-0,10
benzene0,05-0,20
toluene0,21-0,64
ethylbenzenefor 0,19 0,39
p-xylene0,04-0,07
m-xylene0,18-0,34
o-xylene0,85-1,46
isopropylbenzene1,38-1,74
styrenethe 4.65-6,41
the amount of ethyltoluene7,88-10,02
the Dicyclopentadiene3,44-was 4.02
the amount of mesitylene and tertbutylbenzenewas 2.76-3,54
pseudocolor15,34-17,77
alpha methylsterolto 9.91-12,16
p-diethylbenzene2,61-4,08
the amount of m-diethylbenzene and Indiana6,67-being 9.61
o-diethylbenzene5,95-6,99
indenbecomes 9.97-15,39
the durene0,27-0,73
naphthalene1,76-of 4.38
the amount of unidentifiedto 11.11-15,21

The absorbance of aromatic hydrocarbons is carried out at a temperature of minus 10 ÷ + 1°and pressure of 1,2-5,0 ATA. The density of irrigation in the absorber is not less than 5 m3/m2including the process of absorption in sub-zero temperatures involves the density of arose the Oia atmospheric distillation, ensure complete solubility of water in the absorbent material.

The rich absorbent from the absorber 6 through line 8 flows into the collector 4. Neskondensirovannyh gas containing no water from the absorber 6 through line 9 is sent to the drop entrainment 10, at a temperature of minus 10 to minus 15°and pressure of 1,2-5,0 ATA additionally allocated hydrocarbons. The drop entrainment 10 equipped agglomerated device.

Nscontainerframe hydrocarbons from the drop entrainment 10 through line 12 is directed or burning is used as fuel, or for generation of hydrogen gas. Selected hydrocarbons from the bump 10 on line 11 enter the collector 4. Aromatic hydrocarbons and water from the collector 4 through line 13 serves for the production of petroleum resin catalytic method.

The use of the proposed method of separation of aromatic hydrocarbons from nscontainerbox gases styrene production will allow to reduce losses of hydrocarbons, to improve technical and economic performance of the production of styrene by increasing the selectivity of the target response and avoiding contamination of the raw products of side reactions that adversely affects the performance of the catalyst and the properties of the commodity styrene. At the same time due to the absorbed aromatic hydrocarbons improve feasibility demonstration of the prevalence of the production process petroleum resin catalytic method.

The invention is explained with the following examples.

Example 1 (the prototype).

Selection of aromatic hydrocarbons from neskondensirovannyh gas coming from the Department of condensing gas contact process for the catalytic dehydrogenation of ethylbenzene, is carried out in three stages. Neskondensirovannyh gas, volume fraction of aromatic hydrocarbons in which 1,46%, is fed to the first stage in the drop entrainment 2, where at a temperature of 1°and a pressure of 1.2 ATA allocated mechanically gone aromatic hydrocarbons and water. Speed tangentially introduced through line 1 flow neskondensirovannyh gas in the drop entrainment 50 m/S.

In the second stage absorption are etilbenzene the charge composition, mass fraction, %: benzene - 0,03; toluene - 0,7; ethylbenzene - 98,66; styrene - 0,61 at a temperature of 1°and a pressure of 1.2 ATA. Speed neskondensirovannyh gas on the free section of 0.22 m/s gravity irrigation 5 m3/m2PM

In the third stage, the aromatic hydrocarbons are separated from neskondensirovannyh gas drop entrainment 10 at a temperature of minus 10°and a pressure of 1.2 ATA. Speed tangentially introduced through line 9 flow neskondensirovannyh gas in the drop entrainment 50 m/s, the drop entrainment equipped agglomerated device.

After selecting the volume fraction of aromatic hydrocarbons in neckand nirvanna gas in line 12 is 0,008%.

Data material balance flow given in the table.

Example 2.

The process is conducted according to the proposed method. Selection of aromatic hydrocarbons from neskondensirovannyh gas coming from the Department of condensing gas contact process for the catalytic dehydrogenation of ethylbenzene, is carried out in three stages. Neskondensirovannyh gas volume fraction of aromatic hydrocarbons 1,46% is applied to the first stage in the drop entrainment 2, where at a temperature of 1°and a pressure of 1.2 ATA allocated mechanically gone aromatic hydrocarbons and water. Speed tangentially introduced through line 1 flow neskondensirovannyh gas in the drop entrainment 50 m/S.

In the second stage, the absorption of lead atmospheric distillate obtained in the production of petroleum resin catalytic method and hydrocarbon having the following composition, mass fraction of component, %:

pentadien0,21
the cyclopentadiene0,04
benzene0,15
toluene0,30
ethylbenzene0,24
p-xylene0,06
m-xylene0,27
o-xylene1,13
isopropylbenzene 1,55
styreneof 5.40
the amount of ethyltoluene9,10
the Dicyclopentadiene3,75
the amount of mesitylene and tertbutylbenzene3,10
pseudocolor16,40
alpha methylsterol11,00
p-diethylbenzene3,20
the amount of m-diethylbenzene and Indiana7,50
o-diethylbenzene6,50
inden13,40
the durene0,50
naphthalene3,20
the amount of unidentified13,00

Temperature absorption 1°C, a pressure of 1.2 ATA. Speed neskondensirovannyh gas on the free section of 0.22 m/s gravity irrigation 5 m3/m2PM

In the third stage, the aromatic hydrocarbons are separated from neskondensirovannyh gas drop entrainment 10 at a temperature of minus 10°and a pressure of 1.2 ATA. Speed tangentially introduced through line 9 flow neskondensirovannyh gas in the drop entrainment 50 m/s, the drop entrainment equipped agglomerated device.

After selecting the volume fraction of aromatic hydrocarbons in neskondensirovannyh gas in line 12 is 0,002% (table).

Example 3.

The process in the FLS on the proposed method. Selection of aromatic hydrocarbons from neskondensirovannyh gas coming from the Department of condensing gas contact process for the catalytic dehydrogenation of ethylbenzene, is carried out in three stages. Neskondensirovannyh gas volume fraction of aromatic hydrocarbons 2,90% line 1 is the drop entrainment 2, where at a temperature of 3°and a pressure of 3 ATA allocated mechanically gone aromatic hydrocarbons and water. Speed tangentially introduced through line 1 flow neskondensirovannyh gas in the drop entrainment 50 m/S.

In the second stage, the lead absorption by atmospheric distillation (as in example 2) at a temperature of absorption minus 2°and a pressure of 3 ATA. Speed neskondensirovannyh gas on the free section of 0.22 m/s gravity irrigation 5 m3/m2PM

In the third stage, the aromatic hydrocarbons are separated from neskondensirovannyh gas drop entrainment 10 at a temperature of minus 12°and a pressure of 3 ATA. Speed tangentially introduced through line 9 flow neskondensirovannyh gas in the drop entrainment 50 m/s, the drop entrainment equipped agglomerated device.

After selecting the volume fraction of aromatic hydrocarbons in neskondensirovannyh gas in line 12 is 0,002% (table).

Example 4.

The process is conducted according to the proposed method. The volume fraction of aromatic hydrocarbons is neskondensirovannyh gas of 3.6%. Process conditions similar to those suggested in example 3. Balance sheet data in the table.

Example 5.

The process is conducted according to the proposed method. The volume fraction of aromatic hydrocarbons in neskondensirovannyh gas of 3.8%. Process conditions similar to those suggested in example 3. Balance sheet data in the table.

1,31
Table

The material balance of the process of extracting aromatic hydrocarbons from nscontainerbox gases styrene production
ComponentsExample 1

(prototype)
Example 2Example 3Example 4Example 5
1*12**1*12**1*12**1*12**1*12**
1234567891011
Benzene0,710,0060,710,00151,410,00151,750,00191,850,0020
Toluene 0,240,0010,240,00050,480,00050,590,00060,620,0008
Ethylbenzene0,400,0010,400,790,991,04
Styrene0,110,110,220,270,29
Carbon dioxide9,7210,1309,7210,13009,7910,12009,7910,28909,7910,3300
Methane5,886,0405,886,04005,886,05005,886,16305,886,1800
Hydrogen80,0682,48280,0682,488078,7282,488078,1282,171578,0282,1272
Unsaturated1,311,3401,31at 1.34001,31at 1.34001,37401,311,3800
Waterof 1.57of 1.571,401,301,20
Total:100,00100,000100,00100,000100,00100,000100,00100,000100,00100,000
* 1 - composition of the incoming neskondensirovannyh gas lines 1, volume fraction, %

** 12 - composition-facing neskondensirovannyh gas through line 12, volume fraction, %

The method of separation of aromatic hydrocarbons from nscontainerbox gas production of styrene, which includes stages: separation, absorption and separation, characterized in that the absorbent under absorption uses atmospheric distillate obtained in the production of petroleum resin catalytic method and hydrocarbon having the following composition, mass fraction of component, %:

td align="left"> Ethylbenzene
Pentadien0,13-0,24
The cyclopentadiene0,04-0,10
Benzene0,05-0,20
Toluene0,21-0,64
for 0,19 0,39
P-xylene0,04-0,07
M-xylene0,18-0,34
O-xylene0,85-1,46
Isopropylbenzene1,38-1,74
Styrenethe 4.65-6,41
The amount of ethyltoluene7,88-10,02
The Dicyclopentadiene3,44-was 4.02
The amount of mesitylene and tertbutylbenzenewas 2.76-3,54
Pseudocolor15,34-17,77
Alpha methylsterolto 9.91-12,16
P-diethylbenzene2,61-4,08
The amount of m-diethylbenzene and Indiana6,67-being 9.61
O-diethylbenzene5,95-6,99
Indenbecomes 9.97-15,39
The durene0,27-0,73
Naphthalene1,76-of 4.38
The amount of unidentifiedto 11.11-15,21



 

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