Method of obtaining unrefined 1, 3-butadiene

FIELD: chemistry.

SUBSTANCE: described is the method of obtaining unrefined 1, 3-butadiene with the help of extractive distillation from C4-fractions, which contain C4-acetylenes as the secondary components, with the use of a selective solvent. The method is achieved in a column with dividing partitions, which contains in the bottom part an evaporator, in which lengthwise there is a dividing partition, which forms the first zone, the second zone and the underlying combined zone of the column, connected along the upper flow with the extractive washing column. Supply of energy to the column with the dividing partition through the lower evaporator is regulated such that from the column with the dividing partition draw off the lower stream, which contains the solvent, saturated with C4-acetylenes, in which the portion of 1, 3-butadiene is limited with the estimation that the 1, 3-butadiene lost is economically acceptable. In this case the lower stream is submitted into the decontaminator for acetylenes, from which C4-acetylenes are removed and the purified solvent is removed from it from the lower stream.

EFFECT: increase in the periods of the operation of the device between the cleaning cycles.

11 cl, 1 tbl, 1dwg, 1ex

 

The present invention relates to a method for producing the crude 1,3-butadiene from C4the fractions containing4-acetylene as secondary components by extractive distillation using a selective solvent in the column with a dividing partition or thermally jointed columns.

Due to slight differences in the relative volatilities of components4-faction, obtaining 1,3-butadiene from C4-faction is a difficult task in terms of distillation. In this regard, the separation is carried out by extractive distillation, i.e. distillation with the addition of the extractant, which has a boiling point higher than the boiling point of the mixture, you want to share, and increases the difference in relative volatility of the components, which are subjected to a separation. The use of suitable extractants allows by extractive distillation to obtain from the mentioned C4fractions of the crude fraction of 1,3-butadiene, which subsequently additionally purified in the purifying distillation columns.

In the context of the present invention under the crude 1,3-butadiene understand hydrocarbon mixture obtained from C4-faction, from which have been removed, at least 90 wt.% the total content of butane and butenes, preferably, Myung is our least 98 wt.% the total content of butane and butenes, more preferably at least 99 wt.% the total content of butane and butenes, and at the same time, at least 90 wt.% With4-acetylenes, preferably at least 96 wt.% With4-acetylenes, more preferably at least 99 wt.% With4-acetylenes. The crude 1,3-butadiene contains the target 1,3-butadiene, often in a ratio of at least 80 wt.%, preferably 90 wt.%, more preferably more than 95 wt.% other impurities.

Accordingly, under purified 1,3-butadiene understand hydrocarbon mixture, which contains the target 1,3-butadiene in a ratio of at least 98 wt.%, preferably, at least, of 99.5 wt.%, more preferably of 99.7 to 99.9 wt.% other impurities.

In DE-A 10105660 describes how different a simplified design compared to the previously known device:4-fraction is separated in a column with a dividing wall in which such partition reaches the upper edge of the column, and in the extractive wash column above the column with the separation wall. According to the method described in DE-A 10105660, half degassed stream of solvent away from the lower part of the column with the separation wall, which is used for EC is tractive distillation. The term "prodegustirovat solvent " well-known experts in this field who work with extractive distillation to obtain 1,3-butadiene, and means selective solvent, which still contains dissolved components from C4-faction to be split, in particular, components that have the highest affinity with such a selective solvent. Such components, in particular, are C4-acetylene, namely ETHYLACETYLENE and vinylacetylene.

However, the flow of solvent, which was only half degassed, cannot be reused for extractive distillation, because, otherwise, will accumulate acetylene, worsening the course of the process. Therefore, before recirculation on stage extractive distillation stream, which divert from the bottom of the column with baffle this thread you must first send in the degassing column, as described, for example, in DE-A 2724365, which operates at a lower pressure compared to the column, from the lower part of which divert prodegustirovat stream. In the degassing column prodegustirovat the flow of solvent is treated with the purpose of receiving cleared, i.e. completely degassed, the solvent in the lower part and the gaseous hydrocarbon stream at the top is part of the degassing column, through a recycle compressor in the bottom area of the extractive distillation column. Acetylene unloaded through side zipper.

However, according to the method described in DE-A 2724365, the bottom stream, which is removed from the column with a dividing partition and served in the degassing column, in addition to C4-acetylene also contains a significant number of target 1,3-butadiene. The target 1,3-butadiene is directed into the upper part of the degassing column, where the flow on economic considerations cannot be unloaded, but on the contrary, is recycled through the compressor in the extractive distillation column which operates at a higher pressure compared to the degassing column. The above-mentioned compressor absorbs a considerable amount of energy. However, the method according to DE-A 2724365 has advantages compared to previously known methods, which used compressors, which consumes three times more energy. However, at the filing date of the application DE-A 2724365 professionals in the industry was not known that the way in which completely dispense with the use of the compressor, may be technically simple to implement.

In DE-A 10322655 described the way in which can be used to monitor energy use in the column with the separation wall, where feed EN is rgii is provided through the bottom of the evaporator, and also change the number of theoretical plates in the bottom of the joint zone of the column to adjust the column with the separation wall, which allows the removal of the bottom stream, which contains the purified solvent from the column.

Accordingly, there is no need to use degassing columns, and the compressor for recirculation stream containing 1,3-butadiene in the extractive distillation column.

In the context of the present invention under a purified solvent or fully degassed solvent understand the solvent from which the components were removed C4-fraction in an amount to provide the possibility of its use as a selective solvent for extractive distillation With4-faction, while respecting the established requirements of the crude 1,3-butadiene and raffinate 1. The main components in this case are C4acetylene, in particular ETHYLACETYLENE and vinylacetylene.

Accordingly, the present invention is the task of developing an improved method for extractive distillation of 1,3-butadiene in the installation, not containing compressor, which, in particular, reduces clogging of the columns, improved reliability of plants and resistance to conditions of use the.

Hence was developed the method of obtaining the crude 1,3-butadiene by extractive distillation from C4the fractions containing4-acetylene, as secondary components, by using a selective solvent, in column (TC) with a dividing partition, containing in the bottom part of the evaporator (V1), in which the longitudinal direction is set partition (T), forming a first zone (A), the second zone (b) and the underlying combined area of the column (S), and to which predvklyuchen extractive wash column (K), thus the supply of energy to the column (TC) with a dividing wall through the lower evaporator (V1) is adjusted so that the column (TC) with a baffle to divert the bottom stream (17), solvent-loaded C4-acetylene, in which the proportion of 1,3-butadiene is limited so that the loss of 1,3-butadiene are economically acceptable, while the bottom stream (17) is served in a degasser (AG) to acetylenes, from which is distilled With4-acetylene, and the purified solvent away from it in the form of lower flow (27).

It was found that most of the hydrocarbons from C4-fraction in the column on the baffle can be removed, so that, in the selective solvent, essentially, only those hydrocarbons, which are about the have the best ability to dissolve in the solvent, namely C4-acetylene. Therefore, to obtain a purified solvent, which successfully recycle on stage extractive distillation, you just need to extract C4-acetylene from the lower stream in the column with the separation wall. Since the content of 1,3-butadiene in the lower stream of the extractive distillation column can be reduced to small values, economically justified not to recycle this thread on the stage extractive distillation that would entail the need to use energy-intensive compressor.

With4-fraction, which is used in this invention as a raw mixture is a mixture of hydrocarbons containing mainly four carbon atoms in the molecule. With4-faction receive, for example, in the process of producing ethylene and/or propylene by thermal cracking of petroleum fractions, such as liquefied petroleum gas, petroleum ether or light diesel fuel. With4-faction also receive during the catalytic dehydrogenation of n-butane and/or n-butene. In General,4the fraction containing butane, n-butene, isobutene, 1,3-butadiene, as well as additional minor number With3and C5-hydrocarbons, as well as the butins, in particular 1-Butin (ETHYLACETYLENE) and Butenin (vinylacetylene). Soda is the content of 1,3-butadiene is usually from 10 to 80 wt.%, preferably from 20 to 70 wt.%, in particular from 30 to 60 wt.%, while the content of vinylacetylene and ETHYLACETYLENE usually does not exceed 5 wt.%.

Used extractants, namely selective solvents for extractive distillation, already mentioned at the beginning of the formulation of the problem of separation, in particular obtaining 1,3-butadiene from C4-faction, usually are substances or mixtures with a higher boiling point than the mixture to be split, and a higher affinity to solvents with conjugated double bonds and triple bonds than with a simple double bonds or single bonds, preferably dipolar, more preferably dipolar aprotic solvents. Given the characteristics of the device, preferred are substances with low corrosiveness or not possessing such activity.

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 amides, such as dimethylformamide, diethylformamide, dimethylacetamide, diethylacetamide, N-formylmorpholine, N-alkyl-substituted amides (lactams)such as N-alkylpyridine, in particular N-metalpro icon. Typically use N-alkyl-substituted lower aliphatic amides or N-alkyl-substituted cyclic amides. Particularly preferred are dimethyl formamide, acetonitrile, furfural, and in particular, N-organic.

However, it is also possible to use mixtures of these solvents with each other, for example a mixture of N-methylpyrrolidone with acetonitrile, mixtures of these solvents with co-solvents, such as water and/or tert.-butyl esters, for example, methyl-tert.-butyl ether, ethyl-tert.-butyl ether, propyl-tert.-butyl ether, n - or isobutyl and tert.-butyl ether.

N-organic, abbreviation used in this description, NMP, is a particularly suitable solvent, preferably in an aqueous solution containing, in particular, from 7 to 10 wt.% water, more preferably 8.3 wt.% water.

Extractive distillation is carried out in a column with a dividing partition in which this partition is set in the longitudinal direction, forming a first zone, second zone and the underlying joint zone of the column, and which is connected with located upstream of the extractive wash column.

Columns with dividing partitions, as it is known, is used for relatively complex sharing purposes, usually for mixtures of at least three components, each of which is set obtained in pure form. They have a separator, i.e. a flat, smooth sheet, which is usually located in the longitudinal direction of the column and prevent cross-mixing of the liquid and vapour flow in the zones of the column.

For these purposes a special type of a column with a dividing partition whose partition extends to the highest point of the column and, thus, allows to mix the flows of liquid and vapor only in the underlying combined area of the column. Zone, referred to as first and second zones, separated from each other by a dividing partition.

As is well known to specialists in this field, the column of baffle can be replaced with a properly connected, thermally jointed columns.

Extractive wash column is a counter-flow washing column. In all columns the number of internal separation of elements is not limited. For economic reasons it is preferable to random arrangement of grains.

Degasser for acetylenes is a column for distillation of light fractions. The bottom stream containing4-acetylene of the extractive distillation column, is fed into the upper zone of the crystallizer, and C4-acetylene Tegaserod, bringing them into counterflow contact with the acting hot gas stream.

Preferably to the acetylene degasser connected scrubber with water irrigation, in which the remaining solvent from a stream of degassed acetylenes wash irrigating and fresh water. Scrubber water irrigation preferably has a significantly smaller diameter compared to the degasser to acetylenes. In the upper part of the scrubber water irrigation receive a stream containing4-acetylene, which condense and partially returned to the scrubber in the form of reverse flow or otherwise, are unloaded from the installation, in particular load in the cracking apparatus or burn.

The bottom stream of acetylene the crystallizer contains purified solvent and preferably is returned to the extractive distillation column.

In a preferred variant of the method:

- C4-fraction is loaded into the first zone of the column with a dividing partition, preferably in its middle section,

- high flow (2) from the first zone (A) column (TC) with a dividing partition is loaded into the bottom area of the extractive wash column (K)

in the extractive wash column (K) carry out a counter-current extraction by processing the first substream (3) of the selective solvent in the upper zone of the extractive wash column (K)

- components4-faction with more low is th soluble in the selective solvent, than 1,3-butadiene are removed (4) through the top of the extractive wash column (K)

- the bottom stream (7) of the extractive wash column (To) recycle in the upper zone of the first zone (A) column (TC) with baffle

the second substream (13) of the selective solvent is loaded into the column (TC) with a dividing wall in the upper section of the second zone of the column (In)

- extract the product (14) in the upper zone the second zone (B) column (TC) with a dividing partition in the form of crude 1,3-butadiene (16),

from the bottom of the joint zone (C) column (TC) with a baffle to divert the bottom stream (17), comprising a solvent, loaded With4-acetylene, in which the content of 1,3-butadiene is limited so that the loss of 1,3-butadiene economically acceptable,

- the bottom stream (17) is loaded into the degasser (AG) to acetylenes, where4acetylene distilled off and pick through the top, and the purified solvent is obtained as the bottom stream (27), which recycle in the process.

Thus, subject to division With4the fraction is preferably fed to the first zone of the column with a dividing partition, more preferably in its middle section;

the top stream from the first zone of the column with baffle served in the lower zone located upstream of extractiv the Oh wash columns,

carry out a counter-current extraction in the extractive wash column by processing the first substream of the selective solvent in the upper zone of the column,

assign components4-fractions that have a lower than 1,3-butadiene, soluble in the selective solvent through the top of the extractive wash column, and return them partially in the form of reverse flow in the extractive wash column, otherwise assign as a by-product, containing mainly butane and butenes, often also referred to as raffinate 1.

Feeding the bottom stream from the extractive wash column, namely stream containing, in addition to the selective solvent, also 1,3-butadiene, butanes, butenes and components4-faction with the best soluble in the selective solvent than 1,3-butadiene, in the upper zone of the first zone of the column with a dividing partition due to mass transfer between the stream and4-faction supplied in the form of steam in the upper zone of the first zone of the column with the baffle ensures that the extraction in countercurrent flow occurs in the upper part of the first zone of the column with a dividing partition with fewer components with lower solubility in the selective solvent than 1,3-butadiene.

In the lower part is alony with baffle receive vaporous stream, which, in addition to 1,3-butadiene contains components4-faction, in particular, C4-acetylene, which have better solubility in the selective solvent than 1,3-butadiene. Such components are washed away from the rising vapor flow in counter-current with the second substream of the selective solvent, which serves in the upper area of the second zone of the column with a dividing partition. Vaporous product in the upper part of the second zone of the column with a dividing partition assign, preferably by condensation in the condenser, located in the upper part of the column and condensed substream upper thread serves back into the zone In the column with a dividing partition in the form of reverse flow, and, otherwise, condensed upper stream to divert as crude 1,3-butadiene.

At the bottom of the joint zone of the column, the solvent Tegaserod with getting to the bottom of the extractive distillation column solvent containing4-acetylene and 1,3-butadiene in the amount of losses which are economically acceptable.

When determining the power required for these purposes, through the lower evaporator engineer takes into account the stability of the substance or mixture of substances, which are used as the selective solvent is each individual case.

If the temperature of the selective solvent, the temperature in the lower portion of the extractive distillation column is preferably set at a sufficiently high level, so that it is still possible to carry out the condensation in the upper part of the extractive distillation column using inexpensive cooling agents such as river water.

However, if the temperature of the selective solvent used in the individual case, is insufficient to the temperature required to obtain a solvent in the lower zone, in which the quantitative content of the 1,3-butadiene is limited, making it economically acceptable loss, there is a need to work at a temperature in the lower part of the column, which is still valid for the selective solvent and, respectively, for cooling the upper zone of the column with the use of more expensive cooling agent than the river water.

Particularly preferred selective solvent, as mentioned earlier, is NMP, preferably in an aqueous solution containing, in particular, from 7 to 10 wt.% water, more preferably 8.3 wt.% water.

Provided that as a selective solvent NMP is used, the temperature in the lower part of the evaporator of the extractive distillation column pre is respectfully set in the range from 150 to 210° C, more preferably at level 178°C. Accordingly, the pressure in the head part of the second zone of the extractive distillation column having a column design with a dividing wall is from 1 to 10 absolute bar (hereinafter "bar abs."), preferably from 2 to 5 bar abs., more preferably at 3.5 bar abs. Preferably degasser for acetylenes operates at a pressure in the head part in the range from 1 bar abs. until the pressure in the lower part of the column with a dividing partition (TC).

In principle, there is no need to restore a by-product consisting of butane and butenes, known as raffinate 1, located upstream of the extractive wash column, separated from the extractive distillation column. You can also integrate the extractive wash column in the first zone of the column with a dividing wall that is used as the extractive distillation column, when technically and economically feasible to take into account the specific boundary conditions of the process, in particular the composition of4-faction to be split, and the characteristics of raffinate 1 in order to appropriately increase the number of theoretical plates in the first zone of the column with a dividing partition.

Before occhialini variants of the method, described below, which were disclosed for the method according to DE-A 10105660, are also applicable to the method according to the present invention.

According to a preferred variant of the steam flow in the lower part of the dividing wall column with baffle share by using appropriate means so that the substream supplied to the first zone of the column with a dividing partition was larger than the substream supplied to the second zone of the column with a dividing partition. Adjusting the separation of the steam flow in the lower part of the partition provides a safe and easy way to provide the necessary flow characteristics of the crude 1,3-butadiene, which is extracted in the upper part of the second zone of the column with a dividing partition.

This unequal division of the steam flow in the lower part of the partition particularly preferably achieved by the fact that the partition is installed off-center, resulting in the second zone of the column with a dividing partition is smaller than the first area of the column.

The partition wall preferably placed in the center so that the ratio of the cross-section of the first zone to the cross section of the second zone ranged from 8:1 to 1.5:1, in particular of 2.3:1.

As an alternative to the if in addition to the off-center location of the dividing walls of the steam flow in the lower part of the partition can be divided in the desired ratio between the two zones of the column by means of additional means, such as dampers or guide plates.

Another additional or alternative means for separation of the steam flow in the lower part of the partition walls is to install the heat sink condenser in the upper part of the second zone of the column with a dividing partition.

In a preferred variant of the method the pressure in the upper parts of the two zones of the column with the baffle can be adjusted independently. This allows to obtain the required properties of the crude 1,3-butadiene.

The pressure in each of the upper sections of the two zones of the column with a dividing wall is preferably set by means of a demountable switch. The term split switch, as is well known, means a device in which the exhaust pressure regulator simultaneously connected to the pipe for inert gas and air outlet pipe. The valve, which sets the range of the pressure regulator is divided so that only one valve is active at a certain moment, i.e. either passes inert gas, or the gas outlet. This allows to minimize losses of inert gas and the product associated with the stream of exhaust air.

In addition or as an alternative to split switch, the pressure in each of the top sites on the wow zones columns with baffle can be adjusted using a source of heat in kondensatoren in the upper part of the second zone of the column with the separation wall and in the upper part of the extractive wash columns.

In the preferred embodiment, it is possible to integrate acetylene degasser by its installation in the lower zone of the column with a dividing partition. To this end, the number of theoretical plates in the bottom of the joint zone of the column with the separation wall must be correspondingly increased, and the point of the column with the separation wall, which corresponds to the upper end of the acetylene degasser must be installed gas-tight partition, although it is advisable to ensure that the message of the liquid, for example by drainage over the partition and the reverse flow under the partition.

The heat contained in the bottom stream from the extractive distillation column, can be successfully used for heat integration in the process, in particular for heating by indirect heat transfer to the lower stream, which take away from the acetylene degasser, and/or to the liquid withdrawn on one or more stages of separation in the column with the separation wall, heated and/or evaporated through indirect heat exchange with the hot bottom stream and reticularis at the bottom of the joint zone of the column with a dividing wall separation stage(s) are preferably chosen so that the requirements for General the energy cost for extractiv the second distillation in the appropriate column were minimal.

Also or alternatively heat contained in the lower flow of the pure solvent from the acetylene degasser can be used for indirect heat transfer to the liquid is withdrawn on one or more stages of separation in the extractive distillation column, heated and/or evaporated and served back to the extractive distillation column, and/or for heat transfer by indirect heat exchange with C4-faction, which is loaded into the extractive distillation column.

It was found that the integration of heat in this way, due to the much steeper decline in thermal profile of the extractive distillation column, which is observed at the bottom of the evaporator on the bottom stages of the extractive distillation is more favorable compared to existing methods, especially in comparison with the method according to DE-A 10322655, in particular approximately 10% compared to this method.

In this way a special operating mode of extractive distillation in which the removal With4-acetylenes is carried out in the device or separated from the rest of the device, provides increased reliability of the method, since it eliminates the risk of accumulation of acetylenes over their borders collapse.

In addition, a special operating mode provides a fairly good is a pleasant temperature profile in the column with the separation wall: despite the fact that the bottom evaporator of the column with a dividing partition only works at a slightly lower temperature in comparison with the known methods, the temperature, which is critical for clogging, i.e. the temperature is usually >150°With, is not achieved in any of the columns used in the method according to the invention, in particular in the column with the separation wall and acetylene the crystallizer. In contrast, the temperature in the zone in which acetylene undergo degassing significantly reduced, by about 30-40°compared with the known methods, which, in particular, reduces clogging.

Further, the invention is illustrated in detail using a drawing and a working example.

In the drawing 1 shows a diagram of the installation according to the invention.

In the column of the LC with a dividing partition T installed in the longitudinal direction, which divides the column in the first zone And the second zone and the lower joint area With columns, With4-faction 1 served in the first area A. for Example, the second area contains 40 theoretical plates, and the lower joint area contains 10 theoretical plates. The upper thread 2 from zone a miss in the lower zone located upstream of the extractive wash column, having, for example, 20 theoretical plates. In the upper zone extractive industry the adjustment column To download the first substream 3 solvent, where extraction in countercurrent, which receive the lower thread 7, which redirect back to the upper zone And the column TC with baffle and the upper thread 4, which condense in the condenser installed in the upper part of the extractive wash column, and the substream condensate load again in the form of stream 5 in the extractive wash column, or, otherwise, the condensate is to divert as stream 6.

In the second zone In the column TC with a dividing partition load the second substream 13 solvent. From the second zone In the upper stream 14 assign and condense, and the substream 15 of the condensed top stream 14 is injected into the second zone In the column with a dividing partition in the form of reverse flow, or, otherwise, the condensed top stream 14 to divert as crude 1,3-butadiene (stream 16).

From the bottom of the column with a dividing partition (TC) power is supplied from the outside to the installation through the lower evaporator (V1) columns with baffle (TC). Appropriate integration of heat in this method preferably allows the external power supply to install exclusively at this point.

The bottom stream 17, the solvent containing4-acetylene, the content of 1,3-butadiene which does not exceed the upper limit at which losses are economically acceptable, preferably after heat integration with the lower flow of the acetylene degasser (AG), and more preferably a liquid which take away from the bottom of the joint zone (C) columns with baffle (TC), served in acetylene degasser (AG) through the upper zone. In the crystallizer acetylene (AG) the bottom stream 27 containing the purified solvent, and assign, as shown in the drawing, preferably after the integration of heat with the liquid withdrawn from the bottom of the joint zone (S) of the column with the separation wall, as well as with4-fraction, which is fed to the column with the separation wall as a stream of 1, recyclist in this process as stream 3 and stream 13.

To the acetylene degasser (AG) connected scrubber with water irrigation, in which the remaining solvent washed out of degassed flow acetylenes using irrigation and fresh water. In the upper part of the scrubber water irrigation (W) stream 24 containing acetylene, assign, condense in the condenser in the upper part of the column, partially return in the form of reverse flow 25 back into the scrubber with irrigation water (W) or, otherwise, are unloaded from the installation in the form of thread 26.

An example of the method presented in the table.

These flows refer to the installation drawing. As Rast is orites use N-organic, containing 8.3 wt.% water. Under low-boiling components are understood to be contained in the partial mixture of substances, which have a lower boiling point than 1,3-butadiene, and under high-boiling components contained in the partial mixture of substances, which have a higher boiling point than 1,3-butadiene.

The expert attention is drawn to the composition of the initial fraction With the4supplied through the line 1, and the cubic product discharged through line 17. CBM product contains solvent used, almost all the amount of acetylenes With4, high-boiling components (in particular hydrocarbons, C5), as well as a small proportion of 1,3-butadiene, comprising about 1.2% by weight of the content of 1,3-butadiene in the original fraction4. As can be seen from the attached table, the proposed method allows to operate the column with a baffle at a temperature in the cube equal to 179°C. In the manner as stated in the description of the nearest equivalent (DE 10322655) it is necessary to work at temperatures in the cube, which is 10°above that as a result increase the speed of reactions leads to an increase in the degree of clogging in the column. Lower waste temperature according to the invention provides almost double the life of the installation between two cleaning cycles.

Table
An example of the proposed method
Stream1354613151416
Temperature°403842324238423342
Pressurebar5,13,54,64,64,63,64,63,64,6
Thread countkg/h300002525192307040405173017863544301673912265
1,3-butadieneWt.%41,06000,00000,05000,05000,05000,000099,057898,799099,0578
The raffinate II (Butane+Butenes)/td> Wt.%57,81000,000099,654599,570499,65450,00000,35030,34940,3503
Acetylene4Wt.%0,63000,00000,00000,00000,00000,00000,00300,00300,0030
Low-boiling componentsWt.%0,13000,00000,08640,08640,08640,00000,19560,19510,1956
High-boiling componentsWeight%0,17200,00000,00120,00120,00120,00000,16540,16500,1654
The solvent (N-organic+water)Wt.%0,0000of 100.00000,09150,17570,0915of 100.00000,15020,41110,1502

Stream2717NON25242726
The rate is temperature °C142179444999515049
Pressurebar1,4a 3.91,51,51,53,63,61,5
Thread countkg/h33116433143911125964654180289320386
1,3-butadieneBec.%0,00000,04470,00000,097822,980937,66457,050338,3233
The raffinate II (Butane+Butenes)Wt.%0,00000,00000,00000,00200,000860,91735,43360,0000
Acetylene4Bec.%0,00600,05680,00000,212426,17780,00000,000043,5867
Discocytes the e components Bec.%0,00000,00000,00000,00110,00100,11580,01650,0010
High-boiling componentsBec.%0,00000,00940,00000,03014,80140,00930,00178,0004
The solvent (N-organic+water)Bec.%99,993299,8802of 100.000099,595241,82070,388087,33553,0848

1. The method of obtaining the crude 1,3-butadiene by extractive distillation from C4the fractions containing4-acetylene as secondary components, by using a selective solvent, in the column with a dividing partition, containing in the bottom part of the evaporator, in which the longitudinal direction is set partition, forming the first zone, second zone and the underlying joint zone of the column, connected on the upper stream from the extractive wash column, thus the supply of energy to the column with the separation wall through the lower evaporator is adjusted so that from the column with a baffle to divert the bottom stream containing solvent, saturated with the 4-acetylene, in which the proportion of 1,3-butadiene is limited so that the loss of 1,3-butadiene are economically acceptable, while the bottom stream is fed into the crystallizer to acetylenes, from which is distilled With4-acetylene, and the purified solvent away from it in the bottom of the stream.

2. The method according to claim 1, wherein a content of 1,3-butadiene in the bottom stream of the column with a baffle to limit the quantity that a maximum of 0.1-2 times the number With4-acetylenes.

3. The method according to claim 2, in which the content of 1,3-butadiene in the bottom stream of the column with a dividing partition limit to the amount of 0.3 times the number With4-acetylenes.

4. The method according to claim 1, in which the energy of the bottom stream of the column with a dividing wall used for indirect heat exchange with the bottom stream from the crystallizer to acetylenes and/or liquid, which is removed for one or more stages of separation from the bottom of the joint zone of the column with a dividing wall, with phase separation, which drains the fluid, carried out so that the power consumption in the column with the separation wall was minimal.

5. The method according to claim 1, in which the heat contained in the lower stream from the crystallizer to acetylenes, used for indirect heat is BMENA with liquid, you assign one or more stages of separation from the bottom of the joint zone of the column with a dividing wall, with the stage(s) of the separation on which(s) divert fluid, carried out so that the power consumption in the column with the separation wall was minimal, and/or heat contained in the lower stream, used for indirect heat exchange with subject separation With4-faction loaded into the column with a dividing partition.

6. The method according to claim 1, in which

With4-fraction is loaded into the first zone of the column with the separation wall,

the top stream from the first zone of the column with a dividing partition is loaded into the bottom area of the extractive wash column,

in the extractive wash column provide countercurrent extraction by processing the first part of the stream of selective solvent in the upper zone of the extractive wash column,

components4-faction with lower solubility in the selective solvent than 1,3-butadiene are removed through the top of the extractive wash column,

the bottom stream from the extractive wash column recycle in the upper zone of the first zone of the column with the separation wall,

the second part of the stream of selective solvent loading is fair in the column with the separation wall in the upper section of the second zone of the column

extract the product in the upper area of the second zone of the column with a dividing partition in the form of crude 1,3-butadiene,

from the bottom of the joint zone of the column with a baffle to divert the bottom stream comprising the solvent, saturated With4-acetylene, in which the content of 1,3-butadiene is limited so that the loss of 1,3-butadiene economically acceptable,

the bottom stream is loaded into the degasser to acetylenes, where4-acetylene distilled off and pick through the top, and the purified solvent is obtained as the bottom stream, which is recycled in the process.

7. The method according to claim 6, in which4-the fraction of the load in the middle section of the first zone of the column with a dividing partition.

8. The method according to claim 1, in which the temperature in the lower part of the evaporator of the column with a dividing partition set in the range from 150 to 210°C, pressure in the head part of the second zone of the column with a dividing partition set at the level of from 1 to 10 bar abs., and the pressure head in the crystallizer for acetylenes set in the range from 1 bar abs. until the pressure in the lower part of the column with a dividing partition.

9. The method according to one of claims 1 to 8, in which the degasser for acetylenes integrate by placing it at the bottom of the joint zone of the column with the partition p is regardly due to the installation of a larger number of theoretical plates in the bottom of the joint area and by placing a gas-tight septum at the point of the column with baffle which corresponds to the upper end of the degasser to acetylenes, integrated into the bottom of the joint zone of the column.

10. The method according to claim 8, in which the temperature in the lower part of the evaporator of the column with the baffle installed at level 178°and the pressure in the head part of the second zone of the column with a dividing partition set at the level of 2 to 5 bar abs.

11. The method according to claim 8, in which the pressure in the head part of the second zone of the column with a dividing partition set at 3.5 bar abs.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: method of separation of starting mixture (A) consisting of two or more constituents, by extractive distillation with the selective solvent (S) within dividing wall column (TKW), is proposed. The separation is performed in the dividing wall column (TKW) having a dividing wall aligned in a longitudinal direction (TW) and extending to an upper end of the column and dividing an interior of the column into first region (1), second region (2), and lower combined column region (3). The starting mixture is fed into first region (1), first top stream (B) is taken off from first region (1), and second top stream (C) is taken off from second region (2), with each of the streams having a prescribed specification. The selective solvent (S) is introduced in an upper part of first region (1) and/or in an upper part of second region (2), and flow of solvent (S1) into the first region (1) and/or flow of solvent (S2) into second region (2) are set so that each of the prescribed specifications for top streams (B, C) are met.

EFFECT: invented method of dividing mixtures is more efficient in terms of energy and solvent consumption.

6 cl, 7 dwg, 1 tbl

FIELD: petrochemical processes.

SUBSTANCE: invention relates to a method for continuously separating C4-fraction by extractive distillation using selective solvent on extractive distillation column, which method is characterized by a separation barrier disposed in extractive distillation column in longitudinal direction extending to the very top of the column to form first zone, second zone, and underlying common zone. Butanes (C4H10)-containing top stream is withdrawn from the first zone, butenes (C4H8)-containing top stream is withdrawn from the second zone, and C4H6 stream containing C4-fraction hydrocarbons, which are more soluble in selective solvent than butanes and butenes, is withdrawn from underlying common zone of column.

EFFECT: reduced power consumption and expenses.

15 cl, 2 dwg, 2 ex

FIELD: petrochemical processes.

SUBSTANCE: hydrocarbon mixture obtained by extractive distillation of C4-fraction using selective solvent, which mixture contains those C4-hydrocarbons, which are better soluble in selective solvent than butanes and butenes, is subjected to continuous separation. Mixture is supplied to first distillation column, wherein it is separated into top stream, containing 1,3-butadiene, propine, and, if necessary, other low-boiling components and, if necessary, water, and bottom stream containing 1,3-butadiene, 1,2-butadiene, acetylenes, and, if necessary, other high-boiling components. Proportion of 1,3-butadiene in bottom stream of the first distillation column is controlled in such a way as to be high enough to dilute acetylenes beyond the range wherein acetylenes can spontaneously decompose. Top stream from the first distillation column is passed to second distillation column, wherein it is separated into top stream, containing propine, and, if necessary, other low-boiling components and, if necessary, water, and bottom stream containing pure 1,3-butadiene.

EFFECT: simplified process and reduced power consumption.

4 cl

FIELD: petroleum processing and petrochemistry.

SUBSTANCE: in particular, invention aims at producing extraction dearomatized component from reformat of gasoline fraction, which component may be used in production of petroleum solvents such as hexane solvents. Process comprising countercurrent extraction of aromatic hydrocarbons with liquid selective extractant to separate dearomatized component (raffinate) and subsequent extractive rectification of resulting extract phase by distilling off aromatic hydrocarbons is characterized by that liquid selective extractant is diethylene glycol or triethylene glycol, countercurrent extraction is carried out at 125-140°C, extractive rectification is carried out using process steam in presence of saturated selective extractant wherein evaporation of water is performed with the aid of energetic steam, unsaturated selective extractant after extractive rectification and recycled gasoline are sent to extraction stage preliminarily using unsaturated selective extractant as heat carrier to generate process steam, and energetic steam condensate is used to heat recycled gasoline to 80-130°C.

EFFECT: enhanced process efficiency.

3 cl, 1 dwg, 1 tbl, 3 ex

FIELD: petroleum processing.

SUBSTANCE: separation of crude C4-fraction comprises rectification of C4-fraction containing butanes, butenes, 1,3-butadiene, and small amounts of other hydrocarbons, including C4-acetylenes, 1,2-butadiene, and C5-hydrocarbons, via extractive distillation using selective solvent. Crude C4-fraction is fed to middle part of first extractive distillation column and selective solvent is added to column above crude C4-fraction introduction point. Vaporous side stream containing C4-acetylenes together with 1,3-butadiene1,2-butadiene, C5-hydrocarbons, and selective solvent, wherein concentration of C4-acetylenes is below self-decomposition threshold, is withdrawn from the first distillation column from the point below crude C4-fraction introduction point. Top stream containing crude C4-fraction components, which are less soluble in selective solvent than C4-acetylenes, are withdrawn from upper part of the first extractive distillation column.

EFFECT: optimized order of process operations.

21 cl, 1 dwg

FIELD: industrial organic synthesis.

SUBSTANCE: crude 1,3-butadiene is recovered from C4-fraction by extractive distillation using selective solvent on column separated by a partition installed along longitudinal direction of the column to form first and second subzones and underlying common column zone. The column is connected to preswitched flush column. Distillation column operation is controlled by energy supply with the aid of lower evaporator and distribution of a series of theoretical plates within underlying common zone to create bottom stream therefrom consisting of purified solvent.

EFFECT: simplified process technology.

23 cl

FIELD: petrochemical processes.

SUBSTANCE: invention provides a process flow rate comprising at least (i) zone of extractive rectification in presence of polar extractant to produce distillate mainly containing butanes and butane(s); (ii) desorption zone wherein desorption of extractant gives stream containing mainly 1,3-butadiene and. as impurities, at least 2-butene(s) and acetylene hydrocarbons; and (iii) optionally rectification zone for mainly 1,3-butadiene-containing stream. In the latter, α-acetylene hydrocarbons are subjected to liquid-phase selective hydrogenation with hydrogen or hydrogen-containing mixture in presence of solid catalyst containing metal(s) exhibiting high activity in hydrogenation process, preferably non-precious metal(s) on solid support. Temperature is maintained within a range 5 to 75°C at contact time ensuring hydrogenation of no more then 6%, preferably no more than 2% of butadiene present. After hydrogenation, 1,3-butadiene is optionally additionally separated from impurities via rectification.

EFFECT: simplified process.

13 cl, 3 dwg, 2 tbl, 10 ex

FIELD: petrochemical processes.

SUBSTANCE: process involves extractive rectification in presence of extractant mainly containing aliphatic N-alkylamide, while toluene is introduced into rectification column point disposed between extractant inlet and the top of column.

EFFECT: reduced loss of extractant with distillate.

6 cl, 3 dwg, 6 tbl, 6 ex

FIELD: petroleum processing and petrochemistry.

SUBSTANCE: catalysate of reforming of long gasoline fractions containing more than 2% benzene is separated by rectification into three fractions: light-boiling fraction containing mainly nonaromatic C4-C6-hydrocarbons and no more than 1%, preferably no more than 0.5%, benzene; high-boiling fraction containing mainly aromatic and nonaromatic hydrocarbons C7 or higher and no more than 1%, preferably no more than 0.5%, benzene; and benzene fraction boiling within a range of 70-95°C and containing no more than 0.1%, preferably no more than 0.02%, toluene and no more than 0.02% nonaromatic hydrocarbons with boiling temperature above 110°C. Benzene fraction is routed into benzene isolation process involving extractive rectification with polar aprotic solvent having ratio of dipole moment to square root of molar volume above 0.3 db/(cm3/g-mole)1/2, preferably above 0.4 db/(cm3/g-mole)1/2, and boiling temperature 150 to 250°C.

EFFECT: improved quality of benzene.

4 dwg, 2 tbl, 5 ex

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

FIELD: chemistry; obtaining of butadienes.

SUBSTANCE: process is achieved through reaction of 1,2-disubstituted acetylenes with n-BuMgCl, I2 and CuCl in the presence of a zirconocene dichloride catalyst in diethyl ether at 20°C and in molar ratio R-≡-R:h-BuMgCl:Cp2ZrCl2 equal to 10:(22-26):(1.0-1.4). Addition of copper chloride (I) and I2 ether solution is done at 0°C and in molar ratio of components n-BuMgCl:I2 = 1:1.1 and R-≡-R:CuCl = 10:1. The reaction mixture is then mixed in argon at 20°C for 3-5 hours.

EFFECT: high selectivity of butadienes.

1 cl, 1 tbl, 9 ex

FIELD: organic synthesis.

SUBSTANCE: method comprises stirring 1,2-disubstituted acetylenes with n-BuMgCl in diethyl ether in presence of zirconacene dichloride under argon atmosphere at room temperature during 3 h, cooling reaction mass to 0°C and adding I-2 ether solution, and stirring at 20°C for further 3-5 h.

EFFECT: increased selectivity of reaction without use of pyrophoric butyllithium.

1 tbl, 10 ex

FIELD: petrochemical processes.

SUBSTANCE: invention relates to a method for continuously separating C4-fraction by extractive distillation using selective solvent on extractive distillation column, which method is characterized by a separation barrier disposed in extractive distillation column in longitudinal direction extending to the very top of the column to form first zone, second zone, and underlying common zone. Butanes (C4H10)-containing top stream is withdrawn from the first zone, butenes (C4H8)-containing top stream is withdrawn from the second zone, and C4H6 stream containing C4-fraction hydrocarbons, which are more soluble in selective solvent than butanes and butenes, is withdrawn from underlying common zone of column.

EFFECT: reduced power consumption and expenses.

15 cl, 2 dwg, 2 ex

FIELD: petrochemical processes.

SUBSTANCE: hydrocarbon mixture obtained by extractive distillation of C4-fraction using selective solvent, which mixture contains those C4-hydrocarbons, which are better soluble in selective solvent than butanes and butenes, is subjected to continuous separation. Mixture is supplied to first distillation column, wherein it is separated into top stream, containing 1,3-butadiene, propine, and, if necessary, other low-boiling components and, if necessary, water, and bottom stream containing 1,3-butadiene, 1,2-butadiene, acetylenes, and, if necessary, other high-boiling components. Proportion of 1,3-butadiene in bottom stream of the first distillation column is controlled in such a way as to be high enough to dilute acetylenes beyond the range wherein acetylenes can spontaneously decompose. Top stream from the first distillation column is passed to second distillation column, wherein it is separated into top stream, containing propine, and, if necessary, other low-boiling components and, if necessary, water, and bottom stream containing pure 1,3-butadiene.

EFFECT: simplified process and reduced power consumption.

4 cl

FIELD: petroleum processing.

SUBSTANCE: separation of crude C4-fraction comprises rectification of C4-fraction containing butanes, butenes, 1,3-butadiene, and small amounts of other hydrocarbons, including C4-acetylenes, 1,2-butadiene, and C5-hydrocarbons, via extractive distillation using selective solvent. Crude C4-fraction is fed to middle part of first extractive distillation column and selective solvent is added to column above crude C4-fraction introduction point. Vaporous side stream containing C4-acetylenes together with 1,3-butadiene1,2-butadiene, C5-hydrocarbons, and selective solvent, wherein concentration of C4-acetylenes is below self-decomposition threshold, is withdrawn from the first distillation column from the point below crude C4-fraction introduction point. Top stream containing crude C4-fraction components, which are less soluble in selective solvent than C4-acetylenes, are withdrawn from upper part of the first extractive distillation column.

EFFECT: optimized order of process operations.

21 cl, 1 dwg

FIELD: industrial organic synthesis.

SUBSTANCE: crude 1,3-butadiene is recovered from C4-fraction by extractive distillation using selective solvent on column separated by a partition installed along longitudinal direction of the column to form first and second subzones and underlying common column zone. The column is connected to preswitched flush column. Distillation column operation is controlled by energy supply with the aid of lower evaporator and distribution of a series of theoretical plates within underlying common zone to create bottom stream therefrom consisting of purified solvent.

EFFECT: simplified process technology.

23 cl

FIELD: petrochemical processes.

SUBSTANCE: invention provides a process flow rate comprising at least (i) zone of extractive rectification in presence of polar extractant to produce distillate mainly containing butanes and butane(s); (ii) desorption zone wherein desorption of extractant gives stream containing mainly 1,3-butadiene and. as impurities, at least 2-butene(s) and acetylene hydrocarbons; and (iii) optionally rectification zone for mainly 1,3-butadiene-containing stream. In the latter, α-acetylene hydrocarbons are subjected to liquid-phase selective hydrogenation with hydrogen or hydrogen-containing mixture in presence of solid catalyst containing metal(s) exhibiting high activity in hydrogenation process, preferably non-precious metal(s) on solid support. Temperature is maintained within a range 5 to 75°C at contact time ensuring hydrogenation of no more then 6%, preferably no more than 2% of butadiene present. After hydrogenation, 1,3-butadiene is optionally additionally separated from impurities via rectification.

EFFECT: simplified process.

13 cl, 3 dwg, 2 tbl, 10 ex

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

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to technology for isolation and purification of butadiene prepared by thermal cracking of hydrocarbons followed by removing heavy by-side products from crude butadiene flow after the selective hydrogenation of undesirable impurities. The flow outgoing from the reaction zone of the selective hydrogenation is fed into evaporator with fraction zone for extraction of butadiene wherein this zone is sprayed with the raffinate flow from the zone of butadiene extraction. From the evaporator the vapor phase containing butadiene with reduced concentration of by-side products is removed and fed to the stage for isolating the concentrated liquid phase comprising heavy by-side products of the reaction. Butadiene-containing vapor phase is recovered to the zone for extraction of butadiene. The fraction zone comprises from 3 to 7 theoretical plates. The temperature in evaporator is maintained in the range from 27°C to 93°C under the pressure value from 375 to 790 kPa. Invention provides the improved technology in preparing the purified butadiene.

EFFECT: improved method for treatment.

5 cl

FIELD: petrochemical processes.

SUBSTANCE: 1,3-butadiene is obtained via catalytic dehydrogenation of n-butylenes at 580-640°C and essentially atmospheric pressure while diluting butylenes with water steam at molar ratio 1:(10-12) and supplying butylenes at space velocity 500-750 h-1. Catalyst is composed of, wt %: K2O 10-20, rare-earth elements (on conversion to CeO2) 2-6, CaO and/or MgO 5-10. MoO3 0.5-5, Co2O3 0.01-0.1, V2O5 0.01-0.1, and F2O3 the balance. Once steady condition is attained, dehydrogenation is carried out continuously during all service period of catalyst.

EFFECT: increased yield of 1,3-butadiene and process efficiency.

2 ex

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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