Method for production of crude 1,3-butadiene by extractive distillation of c4-cut and device therefor

FIELD: petroleum industry.

SUBSTANCE: process in carried out in column having divider arranging in longitudinal direction to form the first section, the second one and the third bottom joint section, wherein extractive scrubber is includes before divider.

EFFECT: simplified technology.

16 cl, 3 dwg

 

The invention relates to a method for producing a crude 1,3-butadiene by extractive distillation of a selective solvent, and suitable for this installation.

Obtaining the crude 1,3-butadiene from C4-faction due to the small differences of the components4-fractions according to their relative volatility is a complex issue in relation to techniques for distillation. Therefore, the division performed the so-called extractive distillation, i.e. by distillation with the addition of extracting agent, which has a higher boiling point than to be separation of the reaction mixture and which increases the difference in relative volatility subject to Department components. Application of a suitable extracting agent of the above With4-fraction by extractive distillation can be obtained fraction of crude 1,3-butadiene, which is then purified in the purifying distillation column, along with a stream that contains less soluble hydrocarbons than 1,3-butadiene in particular, butane and butenes, and stream that contains more easily soluble hydrocarbons than 1,3-butadiene, in particular, the butins, as well as optional 1,2-BUTADIENES.

In this application the crude 1,3-butadiene denotes a mixture of hydrocarbons that contains the target product of 1,3-butadiene in an amount of less than the least 80 wt.%, preferably 90 wt.%, particularly preferably 95 wt.%, the rest of the dirt.

In contrast, pure 1,3-butadiene denotes a mixture of hydrocarbons that contains the target product of 1,3-butadiene in the amount of at least 99 wt.%, preferably of 99.5 wt.%, especially preferably of 99.7 wt.%, the rest of the dirt.

In the application DE-A 2724365 describes a method of obtaining 1,3-butadiene from C4-faction, in which the first extractive distillation get crude 1,3-butadiene, which is then transferred to pure 1,3-butadiene.

According to the method according to DE-A 2724365 extractive distillation is carried out in the system with three columns, in the so-called main scrubber, in counter-flow washing column, respectively, in the column re-flushing. In the main scrubber turned to vapor4-fraction in a counter is provided in contact with the extractant, in particular, N-organic. When this absorption is better soluble in N-organic components propyne, Butenin, 1-buten, 1,2-butadiene, 1,3-butadiene and CIS-2-butene. Soluble in N-organic worse than 1,3-butadiene components, in particular, a mixture of butenes and butane gases are discharged into the upper part of the main scrubber. CBM product main scrubber is pumped into the top of the second column installation extractive distillation namely counter-flow washing column. This column consists of the upper and lower parts, which have different objectives. The upper part of the technologically is a continuation of the main scrubber, while the lower part is attached to the column re-flushing. In the upper part of butenes distills dissolved in the solvent components and again served in the main scrubber. In the transition zone between the lower part and the upper part of the counter-flow washing column is given enriched 1,3-butadiene stream, which, in addition, contains better soluble than 1,3-butadiene components, in particular, With3- and4-acetylene, and 1,2-butadiene, CIS-2-butene and C5-hydrocarbons. As the transition from the lower to the upper part of the counter-flow washing column is part of the current pair up, to ensure good mass transfer across the column from hydrodynamic considerations the upper part of the counter-flow washing column must be performed with a smaller diameter than the lower part. Required for this narrowing from the constructive point of view is more difficult to implement compared to a column with a constant diameter over the entire height.

In the lower part of the countercurrent column is pre-degassing dissolved in N-organic hydrocarbons, partially degassed N-organic pumped for p is lnai degassing in the final column degassing.

From the output of the transition zone between the lower and upper parts of the counter-flow washing column vapor containing 1,3-butadiene stream in the third column installation extractive distillation column re-flushing, removed From4-acetylene by selective countercurrent leaching through N-methylpyrrolidone. Soluble in N-organic better than 1,3-butadiene, parts 1-butyn and Butenin into solution and in the upper part of the column re-flushing receive a so-called crude 1,3-butadiene, a hydrocarbon mixture with the above concentration of the desired product, 1,3-butadiene, which as a mixture contains more 1,2-butadiene, propyne, CIS-2-butene, as well as With5-hydrocarbons.

CBM product columns re-flushing, namely loaded With4-acetylene and 1,3-butadiene N-organic, is pumped back into countercurrent leaching column. With4-acetylene there again in the lower part of the countercurrent washing of the column, where they, together with the partially degassed by a stream of N-methylpyrrolidone in order to conduct a complete degassing served in the column of final degassing. The issue With4of acetylene from the system, as side offtake of the column final degassing through a stage of washing with water to prevent loss solution is a dye, and partial condensation of the cooling water.

Processing the loaded N-methylpyrrolidone occurs after heating and degassing of the lower part of the countercurrent washing column in the above-mentioned column of final degassing, the lower part of which get fully degassed N-organic and in the upper part of which has a gaseous stream of hydrocarbons through the compressor is returned to the lower zone of countercurrent washing column.

Known from DE-A 2724365 way to obtain the crude 1,3-butadiene by extractive distillation With4-faction has in particular the disadvantage that it must be carried out in the installation extractive distillation with three columns, with the middle pillar, namely countercurrent rinsing the column for reasons of hydrodynamics must be performed with a larger diameter in the upper part and with a smaller diameter at the bottom and therefore must be equipped with a complex in a constructive sense of constriction between the upper and lower parts.

The present invention is to develop an improved, in particular more cost-effective way to obtain the crude 1,3-butadiene by extractive distillation With4-faction, as well as suitable for this installation extractive distillation.

This problem is solved by the way the floor is placed the crude 1,3-butadiene by extractive distillation With 4-faction selective solvent in the column with partitions, where a partition is located in the longitudinal direction of the column with the formation of the first section, second section and third lower joint section of the column, and included before the extractive column scrubber.

Thus the present invention proposes a method of obtaining a crude 1,3-butadiene by extractive distillation, which requires only two columns that have the same diameter throughout the height of the column and are not narrowing.

Used as the source of a mixture of the so-called4-fraction is a mixture of hydrocarbons, predominantly four carbon atoms in the molecule. With4-factions are formed, for example, upon receipt of ethylene and/or propylene by thermal decomposition of a kerosene fraction, such as liquefied petroleum gas, gasoline or gas oil. In addition, With4the fraction obtained when the catalytic dehydrogenation of n-butane and/or n-butene. With4-fractions contain, as a rule, butane, n-butene, isobutene, 1,3-butadiene, along with a small amount of3- and5-hydrocarbons, as well as the butins, in particular, 1-butyn (ETHYLACETYLENE) and Butenin (vinylacetylene). The content of 1,3-butadiene is in General from 10 to 80 wt.%, preferably, from 20 to 70 wt.%, in private the tee, from 30 to 60 wt.%, while the content of vinylacetylene and ETHYLACETYLENE in General does not exceed 5 wt.%.

Typical C4-fraction has the following composition in wt.%:

propane0-0,5
propene0-0,5
PROPADIENE0-0,5
propyne0-0,5
n-butane3-10
and-Bhutan1-3
1-butene10-20
ISO-butene10-30
TRANS.-2-butene2-8
CIS-2-butene2-6
1,3-butadiene30-60
1,2-butadiene0,1-1
ETHYLACETYLENE0.1 to 2
vinylacetylene0,1-3
With5-pivdorozi0-0,5

When the above extractive distillation to obtain 1,3-butadiene from C4-faction as astrigent, i.e. as the selective solvent, in General, suitable substances or mixtures, which have a higher boiling point than to be separation of the mixture, as well as higher chemical affinity with conjugated double bonds or triple bonds than with a simple double bonds, as well as simple the links preferably dipolar, in particular, dipolar-aprotic solvents. Preferred little or no corrosive substances.

Suitable selective solvents for the method according to the invention are, for example, butyrolactone, NITRILES such as acetonitrile, propionitrile, methoxypropionitrile, ketones, such as acetone, furfural, N-alkyl substituted lower aliphatic acid amides, such as dimethylformamide, diethylformamide, dimethylacetamide, diethylacetamide, N-formylmorpholine, N-alkyl substituted cyclic acid amides (lactams)such as N-alkylpyridine, in particular, N-organic. In General, use of N-alkyl substituted lower aliphatic acid amides or N-alkyl substituted cyclic acid amides. Particularly preferably used dimethylformamide and, in particular, N-organic.

Can also be used mixtures of these solvents, for example, a mixture of N-methylpyrrolidone with acetonitrile, mixtures of these solvents with other solvents, such as water and/or tert.-butyl ether, for example, methyl-tert.-butyl ether, ethyl-tert.-butyl ether, propyl-tert.-butyl ether, n - or ISO-butyl-tert.-butyl ether.

Particularly suitable N-an organic, preferably in aqueous solution, in particular from 7 to 10 wt.% water, particularly preferably from 8.3 wt.% water.

According to the of the invention the method is carried out in the column, in which one partition is located in the longitudinal direction of the column with the formation of the first section, second section and third lower joint section, and before which included extractive scrubber.

Columns with the partitions are usually used for complex tasks division, generally for the separation of mixtures with at least three components, and individual components should be obtained in pure form. These columns have a partition, i.e. usually located in the longitudinal direction of the column flat sheet, which prevents cross-mixing of liquid and vapor flow in the column sections.

According to the invention has a particular execution columns, the wall of which goes to the top of the column and this allows the mixture of liquid and vapor flows only in the lower joint section. The so-called first and second sections separated from each other by a partition.

Extractive scrubber is a countercurrent washing column and corresponds mainly known from the prior art the main scrubber. Extractive scrubber, however, has when compared with the known from the prior art installed capacity smaller structural height than the main scrubber as part of the task of separation of the main scrubber adopted the upper area of the first section to the Onna bulkhead. The terms "area" and "part" are used in the context of the present invention in relation to the columns, partitions and scrubber as synonyms.

According to a preferred form of the method

- C4-faction served in the first section, preferably in its middle zone,

- head-stream of the first column section with a partition served in the extractive scrubber, in its lower area,

in extractive scrubber spend countercurrent extraction by processing With4-faction first part of the stream of selective solvent in the upper zone extractive scrubber

less soluble in the selective solvent than 1,3-butadiene components4-faction away from the upper part (head stream) extractive scrubber

- CBM product from the extractive scrubber serves in the upper zone of the first column section with a partition,

in a column divider in the middle part of the second section serves the second part of the stream of selective solvent

from the bottom of the column with a partition assign a selective solvent, saturated along with 1,3-butadiene more soluble in the selective solvent than 1,3-butadiene components4-faction, and

- head product of the second column section with a partition assign as a crude 1,3-butadiene.

Preferably, subject to section the structure With 4-fraction is fed to the first section of the column with a partition, particularly preferably in its middle zone; the head stream of the first column section with a partition served in the upstream extractive column scrubber, in its lower area, extractive scrubber spend countercurrent extraction by processing With4-faction first part of the stream of selective solvent of the upper in the upper zone extractive scrubber;

less soluble in the selective solvent than 1,3-butadiene components C4-faction away from the upper zone extractive scrubber, particularly preferably condense it into the condenser in the upper part of the extractive scrubber and of the flow of condensate back to the extractive scrubber, and assign the rest of the condensate, containing predominantly butanes, and butenes, a by-product.

The return of the cubic extractive flow scrubber, i.e. flow, which, along with the selective solvent contains 1,3-butadiene, and better than 1,3-butadiene soluble in the selective solvent components4-faction, in the upper zone of the first column section with a partition when the output is less soluble in the selective solvent than 1,3-butadiene, components in the upper part of the first section of the column with a partition may due to mass transfer between the flow and Tim vapor 4-faction to happen countercurrent extraction.

In the lower end of the partition has a vapor stream, which, along with 1,3-butadiene contains more soluble in the selective solvent than 1,3-butadiene, components4-faction, in particular, C4-acetylene. They are leached from the rising vapor stream is fed countercurrent to the second part of the stream of selective solvent, which is served in the middle zone of the second section of the column with a partition. Vaporous head product of the second column section with a partition assign, condense in the condenser in the upper part of the column, a portion of the condensed downstream of the return flow in the middle part of the section columns with the partition as phlegmy and the rest of the condensed head flow away as crude 1,3-butadiene.

The lower joint section of the column with a partition technologically corresponds to the lower part of the countercurrent washing column is known from the prior art installation of extractive distillation. In it, similar to the corresponding part of the installation of the prior art, pre-degassing of dissolved in the selective solvent hydrocarbons, their return to the appropriate extension of the main scrubber first section of the casing wall and the frequent removal is a rule of saturated solvent from the bottom of the column to fully degassing in the final column degassing.

According to a preferred variant of the process steam stream at the lower end of the partitioning columns share, appropriate measures so that part of the flow, which served in the first section of the column with a partition that is larger than the portion of the stream, which serves the second section of the separation column with a partition. By adjusting the separation of the steam flow at the lower end of the partition may be a simple and reliable way to provide the required specification discharged into the top of the second column section with the wall of the flow of crude 1,3-butadiene.

Especially preferably such unequal separation of the steam flow in the lower end of the partition is achieved by the fact that the partition is located outside mid, namely in such a way that the second section is smaller than the first section of the column with a partition.

Particularly preferably, the baffle is located outside the middle so that the ratio of the cross-section of the first section to the second section is from 8:1 to 1.5:1, in particular of 2.3:1.

Alternative or additionally to the location of the partitions out of the middle of the steam flow at the lower end of the partition can be shared by other measures, for example, valves or guides the sheets in the desired ratio on both sections of the column with a partition.

D. the u additional or alternative possibility of separation of the steam flow at the lower end of the partition is to adjust the power dissipation of the capacitor in the upper part of the second column section with a partition.

A preferred variant of the method according to the invention is that the pressure in both the first and second column sections with a partition can be adjusted separately. Consequently the required specification crude 1,3-butadiene.

Pressure in the upper part of both the first and second column sections with a partition can be installed preferably by known regulation of the Split-Range. Regulation of the Split-Range means this embodiment, when the output of the pressure regulator at the same time connected with a pipe for inert gas and vent pipe. The control range of the valve of the pressure regulator is divided so that each time it is actuated only one valve, either supplied inert gas or is ventilation. This can be brought up to a minimum amount of inert gas, and connected with the exhaust gases flow loss product.

In addition or alternative to the regulation of Split-Range adjustment possible pressure in the upper part of the two column sections with a partition via the power dissipation of the capacitor at the top of the second column section with a partition, respectively, in the upper part of the extractive scrubber.

According to a preferred variant implementation of the invention, the pressure in the upper part of the second is th column section with a partition more than the top of the first column section with a partition, in particular, 1-100 mbar, particularly preferably 1-30 mbar. This makes it possible to abandon rigidly welded or difficult sealed partitions and apply inexpensive loose baffle. Because directed from the second to the first column section with a partition pressure differential liquid or gaseous streams leakage can occur only in this area and together with this may not affect the purity of the exhaust from the upper part of the second section of the target product, the crude 1,3-butadiene.

Preferably the pressure in the upper part of the second section of the column with a partition set in the range of 3 to 7 bar (abs), in particular, 4-6 bar (abs). This enables the condensation of water as a cooling means in the upper part of the column with a partition, expensive cooling means are not required.

The object of the invention is also an installation for carrying out the method of obtaining a crude 1,3-butadiene by extractive distillation With4-faction selective solvent comprising a column partition, one partition is located in the longitudinal direction of the column with the formation of the first section, second section, and the lower joint section, and the upstream extractive column scrubber.

The agreement is but a preferred form of execution the column partition contains as providing separate inserts in all zones of the column, in addition to the area above the supply of the second part of the flow of solvent to the second section, supplied with plates, has a nozzle or ordered packing. Alternative or additionally, the upstream extractive column scrubber above the supply of the first part of the flow of the solvent has as providing separate inserts plates and below the supply of the first part of the stream of solvent nozzles or ordered packing.

The upper area of the second section of the column with a partition above the supply of the second part of the flow of the solvent must be equipped with plates due to low load fluid. The same is valid for the upper zone extractive scrubber above the supply of the first part of the stream of solvent.

Otherwise, as in the column with the partition and extractive scrubber as the preferred providing a separation device provided with nozzles or ordered packing.

Due to the high proportions of the components with enhanced susceptibility to polymerization and the associated increased risk of contamination of equipment in the lower zones of both column sections with a partition used preferably larger nozzles or ordered packings compared to the upper zone of the column sections with a partition.

Especially preferred installation that has a column with Perigord the th, which is provided in the first section under the supply With4-faction layer of nozzles 23 theoretical stages and higher supply With4-faction - layer nozzle 12 theoretical stages, in the second section above the inlet of the second part of the flow of the solvent - 6 practical plates and below the supply of the second part of the flow of the solvent layer of the nozzles with 30 theoretical stages and in the lower joint section columns with wall - layer nozzle 7 theoretical stages and/or extractive scrubber above the supply of the second part of the flow of the solvent in the upper zone holds 6 practical plates and located underneath the layer of nozzles 15 theoretical stages.

Thus the invention proposes a device for producing a crude 1,3-butadiene by extractive distillation With4-faction, which in comparison with the known installations with three columns require only two columns, and these two columns are executed with a constant diameter over its entire height. As a consequence, when the same power as compared with the known from the prior art installation investment costs reduced by 10%.

The invention is explained below using the drawings, which show:

1 is a diagram of the installation according to the invention with a schematically depicted by a dividing partition in the column on figa;

figure 2 - CX the mu install on the technical level.

figure 1 shows the installation according to the invention. In the separation column TC located in the longitudinal direction of the column partition T, which divides the column to the first section And the second section and the third lower joint section, the first section And served With4-faction 1. Head flow 2 sections And served in the lower zone, the upstream extractive column scrubber K. In the upper zone extractive scrubber To serve the first part of the flow of solvent 3. When this takes place countercurrent extraction, which is obtained CBM stream 7, which is returned to the upper area of the section And column of the LC and the main stream 4, which is condensed in the condenser W2, placed in the upper part of the extractive scrubber K. Obtained in this part of the condensate flow as stream 5 return in extractive scrubber, and the rest of the condensate away as stream 6.

The second section of the columns with the partition TK serves the second part of the flow of the solvent 13. From the bottom of the column with a partition is given partially degassed in the lower joint section With the thread 17, and from the second section of the In - head flow 14, which condense in the condenser W1. The resulting stream 15 return as phlegmy the second section of the columns with the partition, and the rest of the flow is given as with the cerned 1,3-butadiene (stream 16).

To clarify the location of the partition T in the column TC and educated these sections in the column serves as a schematic image figa. Partition T, which is arranged in the longitudinal direction of the column TC, divides it into the first section And the second section and the lower joint section C.

In contrast, figure 2 shows the scheme of the prior art. While the same flows as in figure 1 have the same position. Three forming unit for extractive distillation column marked positions I to III.

1. A method of obtaining a crude 1,3-butadiene by extractive distillation With4-faction selective solvent, characterized in that the method is carried out in the column on the partition where the partition is located in the longitudinal direction of the column with the formation of the first section, second section and third lower joint section and before which included extractive scrubber.

2. The method according to claim 1, characterized in that With4-faction served in the first section, preferably in its middle part, the head stream of the first column section with a partition served in the extractive scrubber in its lower zone, in extractive scrubber spend countercurrent extraction by processing With4-faction first part of the stream of selective solvent in the upper zone extractive scrubba is a, less soluble in the selective solvent than 1,3-butadiene, components4-faction away from the upper part (head stream) extractive scrubber, CBM product from the extractive scrubber serves in the upper zone of the first column section with a partition in the casing with a partition in the middle part of the second section serves the second part of the stream of selective solvent from the bottom of the column with a partition assign a selective solvent, saturated along with 1,3-butadiene more soluble in the selective solvent than 1,3-butadiene, components4-faction and the head product of the second column section with a partition assign as a crude 1,3-butadiene.

3. The method according to claim 2, characterized in that less soluble in the selective solvent than 1,3-butadiene, components4-faction away from the upper part of the extractive scrubber as head flow, condense it into the condenser, the flow of condensate as the phlegm return in extractive scrubber and assign the rest of the condensate and/or assign the head product of the second column section with a partition, condense in the condenser in the upper part of the column with a partition, the portion of the return flow in the middle part of the second column section with a partition and the rest of the condensed parent stream to divert as crude 1,3-butadiene.

4. The method according to claims 1 and 2, characterized in that the steam flow at the lower end of the partition column is divided so that part of the flow, which served in the first section of the column with a partition that is larger than the portion of the stream, which serves the second section of the column with a partition.

5. The method according to one of claims 1 to 4, characterized in that the method is carried out in the column on the outside of the middle of the partition.

6. The method according to claim 5, characterized in that due to the location of the partitions out of the middle of the ratio of cross-sections of the first section to the second section is from 8:1 to 1.5:1, in particular of 2.3:1.

7. The method according to one of claims 4 to 6, characterized in that the separation of the steam flow at the lower end of the partition is carried out by regulating the power dissipation of the capacitor in the upper part of the second column section with a partition.

8. The method according to one of claims 1 to 7, characterized in that the pressure in the upper part of the first and second sections regulate separately.

9. The method according to claim 8, characterized in that the pressure in the upper part of both the first and second column sections with a partition set by adjusting the Split-range.

10. The method according to one of claims 1 to 9, characterized in that the pressure in the upper part of both the first and second column sections with a partition regulate power dissipation capacitors.

11. The way p is one of the claims 1 to 10, characterized in that the pressure in the upper part of the second section of the column with a partition greater than the pressure in the upper part of the first section of the column with a partition, in particular 1 to 100 mbar, particularly preferably 1 to 30 mbar.

12. The method according to one of claims 1 to 11, characterized in that the pressure in the upper part of the second section of the column with a partition set in the range from 3 to 7 abs. bar, in particular from 4 to 6 absbr.

13. The installation for carrying out the method according to one of claims 1 to 12, comprising a column partition where the partition is located in the longitudinal direction with the formation of the first section, second section, and the lower joint section and the upstream extractive column scrubber.

14. Installation according to item 13, wherein the column partition as providing separate inserts in all zones except zone above the inlet of the second part of the flow of the solvent in the second section, which is equipped with plates, supplied by nozzles or ordered packings, and/or included in front of the column extractive scrubber contains the above supply the first part of the stream of solvent as providing separate inserts plates and below the supply of the first part of the stream of solvent nozzles or ordered packing.

15. Installation according to item 13 or 14, characterized in that the lower joint section and, and in the lower zones of the first and second column sections with the wall is built of larger nozzles or ordered packings compared to the upper areas of the first and second column sections with a partition.

16. Installation according to one of p-15, characterized in that column with a partition provided in the first section under the supply With4-faction layer of nozzles 23 theoretical stages and higher supply With4-faction - layer nozzle 12 theoretical stages, in the second section above the inlet of the second part of the flow of the solvent - 6 practical plates and below the supply of the second part of the flow of the solvent - layer nozzle 30 theoretical stages, and in the lower joint section columns with wall - layer nozzle 7 theoretical stages, and/or extractive scrubber above the filing of the first part of the flow of the solvent provided in the upper part 6 practical plates and located underneath a layer of nozzles 15 theoretical stages.



 

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The invention relates to the field of production of 1,3-butadiene and high-octane products

The invention relates to the production of butadiene-1,3 single-stage vacuum dehydrogenation of n-butane

The invention relates to the petrochemical industry, namely to obtain butadiene by extracting gas from the contact dehydrogenation of butane-butyl mixtures

The invention relates to a method for dehydrogenation of hydrocarbons

FIELD: catalysts of selective hydrogenation of alkynes of C4 fractions.

SUBSTANCE: proposed catalyst contains 1-30 mass-% of copper used as first active component, 0.001-5 mass-% of palladium used as second active component, at least 0.001-6 mass-% of one metal selected from Al, Pt, Pb, Mn, Co, Ni, Cr, Bi, Zr and Mo as co-catalyst; the remainder being one carrier selected from aluminum oxide, silicon dioxide and titanium oxide. Method of production of catalyst includes impregnation of carrier calcined preliminarily with solutions of active components depending on their content in catalyst. Alkynes are removed from C4 fractions enriched with alkynes by means of selective hydrogenation with the use of said catalyst.

EFFECT: enhanced selectivity and stability of catalyst.

31 cl, 2 tbl, 13 ex

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