1,3-butadiene recovery and purification process

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

 

The invention relates to the extraction and purification of 1,3-butadiene from C4-fractions of different origin, containing at least the butenes, α-acetylene hydrocarbons and possibly butanes and small amounts of hydrocarbons With3and C5.

Known [Shuvalov. Isolation and purification of monomers for synthetic rubber. - L.: Chemistry, 1987, p.93-102] the method of extraction of 1,3-butadiene from C4fractions containing at least the butenes and α-acetylene hydrocarbons by extractive distillation in the presence of a polar extractant followed by desorption of the extractant stream containing predominantly 1,3-butadiene. The butenes and butanes (if present) deduce the structure of distillate extractive distillation. Acetylene hydrocarbons With4and partly With the3and 1,2-butadiene is absorbed by the extractant together with 1,3-butadiene and then fall into a desorbed stream containing predominantly 1,3-butadiene. Thus, the method allows to extract only 1,3-butadiene raw unsuitable for use in polymerization processes without additional purification.

Known [Ability. The basic technology of synthetic rubbers. - M., 1959, s-223] the method of extraction of 1,3-butadiene from C4-fractions by chemisorption of water and ammonium acetate solution odnov entei copper with subsequent desorption of 1,3-butadiene from a chemical sorbent. The main problem with this method chemisorption is the formation of atsetilenida copper, which is highly explosive. For this method, you must delete α-acetylene compounds from C4fractions prior to its submission to an area of chemisorption. Currently, the processes of pyrolysis of hydrocarbons is carried out at relatively high temperatures, resulting in the content of acetylene hydrocarbons in C4-the factions are very large (greater than 1%) and is constantly growing. At the same time With4-fractions of pyrolysis now became the main industrial source of 1,3-butadiene (because of the refusal of expensive dehydrogenation of n-butenes).

Known [Shuvalov. Isolation and purification of monomers for synthetic rubber. - L.: Chemistry, 1987, S. 151-154] the cleaning method With the4-factions, mainly With4-pyrolysis fractions, from α-acetylene compounds liquid-phase selective catalytic hydrogenation. As a catalyst for cleaning4fractions from α-acetylene hydrocarbons by hydrogenation using catalysts of the type palladium on solid media (they usually contain 1.3 to 2 wt.% palladium), which are very expensive, and the expense of the higher, the deeper the required clearance from acetylene hydrocarbons.

Use for liquid purification from acetylene hydrocarbon is in C 4-fractions of pyrolysis cheaper and more available catalysts containing precious metals, in particular catalysts of the type "Nickel on solid media, hampered by the fact that at high contents in C4-fractions isobutene (30%) he oligomerizes on Nickel-containing catalysts and quickly deactivates them. Ineffective attempts of gas-phase cleaning With4fractions from acetylene hydrocarbons due to the rapid deactivation of the catalysts formed by oligomers (including oligomers of 1,3-butadiene and acetylenes), as in gas-phase processes do not delete (washout) oligomers of the catalyst.

Known [Pasiecznik and other Album of technological schemes of the main industries of the UK. - L.: Chemistry, 1986, p.27-29] the method of extraction and purification of 1,3-butadiene from C4-factions dual extractive distillation with a polar extractant. When the first extractive distillation after desorption receive 1,3-butadiene raw with large (up to 3%) content α-acetylene hydrocarbons. In the second extractive distillation with a polar agent 1,3-butadiene allocate as distillate, and a stream containing acetylene compounds desorbed from the extractant in a separate desorption column, usually displaying the specified stream as a side stream.

The process can be complicated. A serious weight problem again is the problem it is the fact, that concentrated α-acetylene hydrocarbons explosive and output stream their concentration should not exceed 30%. The role of diluent mainly performs 1,3-butadiene, which makes it large losses of up to 7-10% of the amount contained in the original4-faction.

Be separated from 1,3-butadiene α-acetylene hydrocarbons With4especially present in the greatest quantity Butenin, normal (clear) the rectification is almost impossible, as present in 1,3-butadiene impurities 2-butenes by rectification from more high-boiling impurities are concentrated in the lower part of the column and substantially increase the volatility Butenin with respect to 1,3-butadiene, in the principal amount of Butenin displayed by distillation together with 1,3-butadiene.

We have found that you can quite selective liquid-phase hydrogenation α-acetylene hydrocarbon stream containing predominantly 1,3-butadiene and does not contain significant amounts of isobutene, such hydrogenation may be carried out on available solid hydrogenating catalysts that do not contain precious metals, in particular, catalysts containing Nickel, copper, cobalt, molybdenum solid media. In this hydrogenation small part of 1,3-butadiene is converted to butenes. At the tableno, that form predominantly 2-butenes and only in significantly fewer (10-20 times compared to 2-butenes) is formed of 1-butene.

2-Butenes do not form azeotropes with 1,3-butadiene, and therefore the resulting 1,3-butadiene with an admixture of 2-butenes can be directed as a commercial product by polymerization or copolymerization. The accumulation of 2-butenes in the polymerization system (it is never 100%, and neapolitanus 1,3-butadiene recycle back into the system polymerization) will not occur, because 1,3-butadiene is usually after polymerization easy attractive.however from 2-butenes.

1-Butene clearly separated from 1,3-butadiene conventional rectification is impossible because of the formation of tangential azeotrope. But found that a small amount of 1-butene formed during the hydrogenation α-acetylene compounds 1,3-butadiene, and can optionally be separated by distillation from the main quantity of 1,3-butadiene in the form of a mixture with 1,3-butadiene and boiling impurities, which can be returned to the extractive distillation system, since it contains 1-butene quite easily (much easier than the 2-butenes) is separated from 1,3-butadiene in the structure of distillate.

It is also possible to further distillation of 1,3-butadiene 2-butenes after hydrogenation, preferably after the distillation of 1-butene.

Department of 1,3-butad the ene by distillation from 1-butene and 2-butenes, as well as 1,2-butadiene, can be combined in a single distillation zone. In this case, the commodity 1,3-butadiene is shown as a side stream from the comprehensive part, below the power supply in a distillation zone.

Alternatively, in the initial4-faction can hold only partial hydrogenation α-acetylene compounds. This will significantly reduce the consumption of the catalyst with precious metal, because the most significant deep hydrogenation α-acetylene hydrocarbons is carried out in a stream of concentrated 1,3-butadiene at a cheap and a more active catalyst (e.g., "Nickel on the media").

We say:

The method of extraction and purification of 1,3-butadiene from C4-fraction of hydrocarbons containing butadiene(s), butenes, butane(s), acetylene hydrocarbons and possibly a small amount of hydrocarbons With3and C5using process flow diagrams, including at least the area of extractive distillation in the presence of a polar extractant with the conclusion in the distillate mainly butenes and butane(s), zone desorption from the extractant stream containing predominantly 1,3-butadiene and mixtures of at least 2-butene(s) and acetylene hydrocarbons, and possibly also including the area(s) of the distillation stream containing predominantly 1,3-butadiene, which specified what the Otok, mainly containing 1,3-butadiene and these impurities, conduct liquid-phase selective hydrogenation mainly α-acetylene hydrocarbons in the presence of a solid catalyst containing the metal(s), with(e) high activity in the hydrogenation, preferably base(s) metal(s) on a solid carrier, and the support temperature in the range from 5°C to 75°and the supply of hydrogen or hydrogen-containing gas mixture and the contact time so that the hydrogenation is subjected to no more than 6%, preferably not more than 2% of butadiene contained and maybe after a specified hydrogenation of 1,3-butadiene is additionally separated from impurities by distillation.

As additional methods implemented in conjunction with the main method defined by paragraph 1 of the claims, we also note the ways in which:

for hydrogenation α-acetylene hydrocarbons in the specified stream containing predominantly 1,3-butadiene, preferably using a catalyst containing Nickel and/or copper and/or cobalt and/or molybdenum on a solid medium

- conduct a two-stage liquid-phase hydrogenation α-acetylene hydrocarbons: original partial hydrogenation in the source4-faction to a residual content α-acetylene hydrocarbons is e more than 0.5% and finally selected after extractive distillation in a stream, mainly containing 1,3-butadiene and these impurities, to a residual content α-acetylene hydrocarbons not more than 0.02%, preferably not more than 0.005%,

- when the content in the source4-faction more than 8% of isobutene for hydrogenation α-acetylene hydrocarbons, it is preferable to use a catalyst containing palladium on a solid medium

area(s) of hydrogenation with the catalyst support completed(s) liquid hydrocarbons and hydrogen-containing stream is served from the bottom through the distribution(s) device(s) or area(s) of hydrogenation with a catalyst irrigate liquid hydrocarbons through the top of the distribution(s) device(s) so that it remains free gas communication between the cross section area of the hydrogenation, the hydrogen source is attached to the hydrogenation zone at one or more points and the depth of hydrogenation regulate by maintaining the necessary partial pressure of hydrogen and temperature

- a stream containing predominantly 1,3-butadiene and these impurities before cleaning the hydrogenation is separated from the impurities of the extractant and possibly other non-hydrocarbonaceous impurities by water washing and/or additional rectification,

after hydrogenation α-acetylene hydrocarbon stream containing predominantly 1,3-butadiene, spend recti is icatio and as distillate output stream, containing the formed 1-butene, partially 1,3-butadiene, boiling impurities and possibly nbutane, which is preferably recycled to the indicated zone extractive distillation, and output VAT residue, containing predominantly 1,3-butadiene,

- a stream containing predominantly 1,3-butadiene and partially impurities, possibly after distillation of the stream containing 1-butene, partially 1,3-butadiene and low-boiling impurities, is subjected to further distillation from the more high-boiling impurities as distillate output commodity 1,3-butadiene,

when distillation of 1,3-butadiene from the more high-boiling impurities from the comprehensive part of this distillation zone output side stream containing 2-butenes and partially 1,3-butadiene, which is preferably returned to the extractive distillation zone, and in the composition of the cubic residue deduce 1,2-butadiene,

- a stream containing predominantly 1,3-butadiene and partially impurities, after purification by hydrogenation is subjected to rectification in the area, with the output side of the stream from its exhaustive part, as distillate output stream containing 1-butene, partially 1,3-butadiene and impurities, as VAT residue remove impurities boiling above 1,3-butadiene, and as a side stream output commodity 1,3-butadiene,

- source4-faction Plevo the cities before serving extractive rectification or her previous partial hydrogenation α -acetylene hydrocarbons are subjected to rectification and her separate thread(s)that contain(s) mainly components with a boiling point above 1,3-butadiene,

- when the specified rectification as VAT residue derive mainly present in the original4-fraction components with boiling points above 20°including hydrocarbons with the number of carbon atoms of more than 4 and you may polymerization inhibitors and corrosion

- when the specified rectification as specified VAT residue or side selection output stream containing a significant portion present in the original4-hydrocarbon fractions With4with boiling points above -1°C, preferably above 4°S, which can be further subjected to hydrogenation to obtain additional quantity of 1,3-butadiene.

The implementation of the invention illustrated in figures 1-3 and examples. Here are the figures and the examples do not exclude the possibility of using other methods subject characteristics (requirements)set out in claim 1 of the claims.

According to figure 1 source4-fraction through line 1. Further, it is served by lines 1A directly in the area of extractive distillation ER, in the upper part of which on line 3 serves extractant e, and/or serves on line 1B in the pre is gidrirovaniya (targetirovanija) feeding hydrogen line 2 and then it is served in an area of AYR.

As distillate from ER on line 4 output stream containing butenes may butane(s) and hydrocarbons With3. If the stream 4 contains a mixture of the extractant, it is separated from hydrocarbons4for example, water washing and return to the process (not shown in figure 1).

As VAT residue from ER output lines 5 a mixture of the extractant with 1,3-butadiene, αacetylene hydrocarbons, a small quantity of 2-butenes and possibly other impurities. Thread 5 served in the desorption column D.

From the column On the bottom line 3 output stream of desorbed extractant, which returned to the area ER.

As distillate (decorate) from column D on line 6 output stream containing predominantly 1,3-butadiene and present in its structure. Stream 6 is directed along the line 6A directly into the purification zone by hydrogenation and/or line 6b served in the purification unit of the admixture of solvent and/or drying (shortly referred to as "purification from admixtures of the extractant) and then it is fed to the hydrogenation zone.

Figure 1 shows two variants of the organization of the hydrogenation zone.

In zone G-1 (enter on line 7a) reactor with catalyst filled with a liquid 1,3-butadiene with impurities). Bottom line 8A through switchgear serves hydrogen or hydrogen-containing gas mixture (N2+). Neproreagirovavshimi the e gases deduce from above on lines 9 and further along the line 9a. Part of the stream 9 may recycle through line 9b. Line 10A output stream is purified from α-acetylene hydrocarbons 1,3-butadiene (1,3-BD+), which can serve as a commercial product.

In zone G-2 (enter on line 7b) of liquid 1,3-butadienestyrene the mixture was fed from the top through the distribution unit. The reactor irrigation is not entirely filled with liquid, so that all sections it freely reported in the gas phase. Area G-2 is connected with a source of hydrogen line 8b (possibly multiple points of entry of hydrogen). When using the hydrogen-containing gas mixture to prevent accumulation of inert components may receive the gas stream 9b.

Bottom line 10A of the G-2 output cleansed α-acetylene hydrocarbons 1,3-butadiene.

Figure 2 shows the allocation of 1,3-butadiene raw, including possible forgetiana α-acetylene hydrocarbons in the source4-faction and possible purification of 1,3-butadienestyrene flow of the admixture of extractant, similar to figure 1. To simplify the zone ER and zone D jointly designated in the block "R+D". Line 5 indicates a thread, together with the recycling arriving at the ER.

Unlike figure 1 is withdrawn from zone G stream 10 is subjected to rectification. The flow line 10A enters the distillation column K-1 and/or line 10B post the AET in a distillation column K-2. As distillate from K-1 output stream 11 containing 1-butene, partially 1,3-butadiene and boiling impurities, which is preferably recycled into the flow of the mixture along the line 11a and/or in the block "R+D" on line 11b.

From the bottom of the K-1 output lines 12 a stream containing predominantly 1,3-butadiene. The specified output stream as a commercial product lines 12A and/or direct on line 12B in the additional column K-2.

From column K-2, if it is used as distillate on line 14 output commodity 1,3-butadiene. Bottom line 13 bring more high-boiling impurities (2-butenes, 1,2-butadiene, and others) and a small amount of 1,3-butadiene. Possible side K-2 output stream 15 containing mainly 2-butenes and partially 1,3-butadiene, preferably returned to the area ER. From Cuba on line 13 deduce the composition of impurities 1,2-butadiene.

Figure 3 differs from figure 2 in that the original4-faction supplied through the line 1, before serving on extractive rectification or forgetiana subjected to rectification from high-boiling components in the area of K-1, and also the fact that for rectification stream containing predominantly 1,3-butadiene, after hydrogenation zone G using one distillation column (2).

In the area of K-1 it is possible to separate and output lines 4 mainly components with temperature is andsinging above 20° With, mainly hydrocarbons, C5and above, as well as present polymerization inhibitors and corrosion. Possible in the K-1 is separated and output line 4 or line 3 (the latter when the output on line 4 stream mainly containing components with a boiling point above 20° (C) a stream containing a significant portion present in the original4-hydrocarbon fractions With4with boiling points above -1°C, preferably above 4°C. the Specified stream at a sufficiently high content Butenin may be further subjected to hydrogenation to obtain additional quantity of 1,3-butadiene (figure 3 not shown).

Further, the allocation of 1,3-butadiene raw, including possible forgetiana α-acetylene hydrocarbons in the source4-faction block "R+D" and possible purification of 1,3-butadienestyrene flow of the admixture of solvent and a hydrogenation zone, similar to figure 2.

In the column K-2 from 1,3-butadiene is separated and light and heavy impurities. As distillate from column To line 14 output stream containing 1-butene, partially 1,3-butadiene and boiling impurities, which preferably recycle in line 1 and/or line 6. The bottom output line 16 stream high-boiling impurities. Side of line 15 or 15A output commodity 1,3-butadiene.

In industry the isolation and purification of 1,3-b is Tatiana mainly carried out With 4fractions obtained in the processes of pyrolysis gasoline, as well as in the processes of single-stage vacuum dehydrogenation nbutane.

In the following examples shows the isolation and purification of 1,3-butadiene these With4-factions. All concentrations are given in wt.%.

EXAMPLES

EXAMPLE 1

Carry out the processing With4-fractions of pyrolysis in accordance with figure 1. Of the dotted lines use line 1A, 6b, 6C, 7a, 8A, 9, 9a, 9b, 10A.

However targetirovanija α-acetylene hydrocarbons in the C4the factions do not produce, use the unit to clean the impurities of the extractant (including drying) and a reaction zone purification by hydrogenation of D-1.

As extractant using acetonitrile mixed with 6-7% of water, as well as inhibitors of polymerization (NaNO2and corrosion. The flow of the extractant in the area ER on line 3 is ≈400 kg/HR Concentration of the extractant in the liquid in the middle part of the ER is 70%.

In zone G-1 hydrogenation catalyst is Nickel (20%) on the diatomaceous earth, the temperature is 20-25°C, a pressure of 2.7-3 ATA. Zone G-1 serves concentrated hydrogen, and part (2/3) output stream 9 recycle input in G-1. The molar ratio of hydrogen: the sum of α-acetylene hydrocarbons is 8:1. The consumption of hydrogen ≈0.35 kg/h

The number and hydrocarbon compositions of the main flow shown in t BL.

EXAMPLE 2

Processing4-fractions of pyrolysis carried out according to figure 1 is similar to example 1.

Unlike example 1 in zone G-1 serves the hydrogen-containing mixture comprising 90 wt.% hydrogen and 10 wt.% of methane. The flow rate of the hydrogen-containing mixture (hydrogen) is ≈0.5 kg/h

The number and hydrocarbon compositions of the basic flow is similar to example 1.

EXAMPLE 3

Processing4-fractions of pyrolysis carried out according to figure 1. The selection of the stream containing predominantly 1,3-butadiene, are similar to examples 1 and 2. Of the dotted lines use line 1A, 6b, 6C, 7b, 8b and 10B.

Unlike examples 1 and 2 purification of 1,3-butadiene the hydrogenation is carried out in a reaction zone G-2 (supply line 76).

In zone G-2 using a Nickel catalyst (25 wt.%) on kieselguhr, keep the temperature of 15-20°and pressure - 2,8-3,2 ATA. Zone G-2 serves concentrated hydrogen. The consumption of hydrogen is 0.08 kg/h

The number and hydrocarbon compositions of the basic flow is similar to examples 1 and 2.

EXAMPLE 4

Processing4-fractions of pyrolysis carried out according to figure 1. A stream containing predominantly 1,3-butadiene, emit similar to examples 1-3. Purification of 1,3-butadiene the hydrogenation is carried out in a reaction zone G-2. In contrast to examples 1-3 as a catalyst in the zone is -2 use the catalyst, containing copper and cobalt on a solid medium (Al2About3). The temperature in zone G-2 - 35-45°With pressure - 5,0-5,5 ATA. Zone G-2 serves concentrated hydrogen. The consumption of hydrogen is 0.08 kg/h

The number and hydrocarbon compositions of the main flow is almost the same as examples 1-3.

EXAMPLE 5

Processing4-fractions of pyrolysis carried out according to figure 1.

Unlike examples 1 and 2 purification of 1,3-butadiene the hydrogenation is carried out in a reaction zone G-2 (supply line 7b).

In zone G-2 using a catalyst containing cobalt and molybdenum on a solid medium comprising Al2About3and SiO2. The temperature in zone G-2 is 65-75°With pressure - 10,5-11,0 ATA. Zone G-2 serves concentrated hydrogen. The consumption of hydrogen is 0.1 kg/h

The number and hydrocarbon compositions of the basic flow is similar to examples 1-4.

The obtained 1,3-butadiene has a concentration 93,6%, contains almost no α-acetylene hydrocarbons. Contained in 2-butenes (5,6%) and 1,2-butadiene (0.4%) do not form with 1,3-butadiene azeotropes and can be easily separated from him by ordinary rectification before or after polymerization.

Table 1
Component (conc. in wt.%)BP., ° Flows (concentration in wt.%)
Examples 1-5Examples 6-7For example 7
Path =1APotPotThe sweat. 10 (10A or 10B)The sweat. 11The sweat. 12The sweat. 13The sweat. 14
Propyne0.10,20,03a 4.9
Butane5,810,40,273,0˜0,2˜0,2˜0,2
Isobutan25,846,2
1-Butene13,524,20,350,0
2-Butenes10,518,20,7of 5.4a 4.9of 87.00,5
1,3-Butadieneto 43.1 1,096,3˜94,842,1˜94,710,099,3
1,2-Butadiene0,10,20,20,22,7<0,01
1-butyn0,20,50,0020,002
Butenin0,92,00,0020,002
Quantity, kg/h100,055,944,144,10,3543,752,7541,0

Notes: 1. Usually in C4-pyrolysis fractions present up to 0.5% other hydrocarbons With3and up to 1-2% of hydrocarbons With5mainly isopentane. They are not included in table 1 because their presence does not matter for illustration of the invention.

2. In the area of ER serves 410 kg/h of an extractant containing 93-96% acetonitrile, 4-7% of water and impurities inhibitors of thermopolymerization butadiene and corrosion.

In stream 4 (when ER with acetonitrile) usually available the t 3 wt.% acetonitrile, then wash with water is distilled off from the aqueous solution and return to the zone ER.

4. In the stream 6 (when ER with acetonitrile) usually contains a small admixture of acetonitrile (0,05-0,2%) and possibly ammonia. The hydrocarbon stream is preferably washed from acetonitrile and ammonia water in the treatment zone from the extractant.

EXAMPLE 6

Processed With4-fraction of pyrolysis according to figure 2. The selection of the stream containing predominantly 1,3-butadiene, and its purification by hydrogenation from α-acetylenes is like 1 as in examples 1-5 (the number and composition of stream 10 in examples 1-5 are almost the same). Of the dotted lines use line 1A, 3, 6A, 10A and 12A.

In contrast to examples 1-5 as an extractant in the allocation of 1,3-butadiene by extractive distillation using N,N-dimethylformamide. Its concentration in the liquid in the Central part of the area ER is supported by several more (≈72,5%)than extractant in examples 1-5, achieving the same separating effect.

In contrast to examples 1-5 1,3-butadienestyrene stream 10 is subjected to further distillation in column K-1 from the more low-boiling compared with 1,3-butadiene impurities, mainly 1-butene and propene mixed with 1,3-butadiene).

Characteristics of streams in the number and composition of hydrocarbons is given in table 1 (including the additional is haunted graphs for threads 11 and 12).

As a result of 100 kg/h4-faction get 43,75 kg/h of 1,3-butadiene concentration 94.7%, admixture of 4.9% 2-butenes, ˜0,2% nbutane and 0,2% 1,2-butadiene. Content α-acetylene hydrocarbons is of 0.004% and meets the requirements of the monomer for the stereoregular polymerization.

Warded off in the amount of 0.35 kg/h stream 11 recycle zone ER.

EXAMPLE 7

Processed With4-fraction of pyrolysis according to figure 1 as in example 6.

In contrast to example 6 1,3-butadienestyrene stream 12 is subjected to further distillation in the column K-2 from the more high-boiling impurities, mainly from 2-butenes, 1,2-butadiene, a small amount of resin and possible hydrocarbon, C5. Of the dotted lines use line 1A, 3, 6A, 10B, 12B, 13 and 14.

Characteristics of streams is given in table 2.

As a result of 100 kg/h4-faction get 41,0 kg/h of 1,3-butadiene concentration of 99.3%, purified from α-acetylene hydrocarbons and 2-butenes (residual content of 2-butenes is 0.5%). The product fully complies with the requirements of the monomer of the highest quality for stereoregular polymerization.

EXAMPLE 8

Processed With4-fraction of pyrolysis, similar to examples 1-7, according to figure 2 using zone targetirovanija (FG). Of the dotted lines use lines 1B, 1C, 2, 3,6A, 9.

In the area of FG using a catalyst containing palladium (˜1 wt.%) aluminum oxide. The temperature in the zone FG - 18°C. the contact Time with the catalyst (75 l/lcacc) and accordingly the flow rate of the catalyst in ˜5 times less than in known industrial process, where the hydrogenation α-acetylene hydrocarbons in the C4-faction lead to a residual content α-acetylene hydrocarbons of 0.02%. The flow of hydrogen - 0.15 kg/h

The residual content α-acetylene hydrocarbons in the C4-mix zone after FY in the stream 5 is 0.1%. The conversion of 1,3-butadiene in botany in the area FG is 0.5%.

The cleaning mode of 1,3-butadiene from α-acetylene hydrocarbons (stream 7) is significantly softer than a temperature of 5-10°C, consumption of hydrogen in the zone G-1 (0.04 kg/h) ˜9 times less than in example 1. In the variant with the use of zone G-2 consumption of hydrogen leaves 0,01-0,02 kg/h is Achieved residual concentration of α-acetylene hydrocarbons less of 0.0004%. The loss of 1,3-butadiene due to its hydrogenation of butenes in the view of his education from Butenin is ˜ 0,4%.

In contrast to examples 1-7 thread 5 coming into the area ER, contains (wt.%): <0,01% propene, 5.9% butane, 25.7 per cent of isobutene, 25.5% of nbutanol, 42.7 percent 1,3-butadiene, ≤0,2% 1,2-butadiene, 0,04-0,05% 1-butyne and 0.05% Butenin. Thread 7 in the amount of ˜42,6 kg/h contains ˜98.8% of the 1,3-Baladi is on, 0.7% of 2-butenes, ˜0,2% 1,2-butadiene, 0,11% 1-butyne, 0,11% Butenin, ≤0,04% propina.

After hydrogenation in zone G-1 or G-2) thread 10 (˜42,6 kg/h) contains 98.4% of 1,3-butadiene, 1,4% 2-butenes, 0,2% 1,2-butadiene, 0.004% α-acetylene hydrocarbons4and 0.003% Pronina. If you increase the supply of hydrogen in G-1 or G-2) total content α-acetylene hydrocarbons3-C4flow ranges from 0.005 to 10%, i.e., meets the requirements monomer for stereoregular polymerization.

Alternatively, the thread 10 is directed to the column 1, after which the total content of α-acetylene hydrocarbons 1,3-butadiene does not exceed 0,004%. In the event of subsequent rectification in the column K-2 concentration trademark butadiene 99.5%.

EXAMPLE 9

Perform isolation and purification of 1,3-butadiene from C4-fractions, obtained single-stage vacuum dehydration nbutane according to figure 3. Submission specified With4-faction is 202 kg/h Of a is shown in dashed lines use lines 2A, 7, 9a and 15A.

From the initial4-fraction, containing a total of 1.0% of the hydrocarbons5-C8and inhibitors, pre-remove these impurities by distillation in column K-1 efficiency 13 theory. saucers.

Targetirovanija α-acetylene hydrocarbons do not hold. In the area of ER extractant (NM-dimethy is formamid) served by the line 7 and maintain its concentration in the middle part of the ER 72%.

Hydrogenation α-acetylene hydrocarbons is carried out in zone G (corresponds to type G-2 in figure 1) in the presence of catalyst Nickel (20%) on kieselguhr" at a temperature of 20°C. Dispersible hydrogen in zone G-1 served in a molar ratio to the sum α-acetylene hydrocarbons 9:1.

After purification from α-acetylene hydrocarbons by hydrogenation carry out the separation of the thread 13 in a distillation column having a side stream output 15A in the strengthening part.

Characteristics of the main hydrocarbon streams is given in table 2.

Table 2
Component (conc. in wt.%)BP., °Flows (concentration in wt.%)
PotPotPotPotPotPotaPot
Propyne0,0070,0020,0010,2
Butane38,046,00,020,10,05
Isobutan3,03,6ÈA;
1-Butenethe 15.619,40,2849,8
2-Butenes26,030,74,05,10,20,389,7
1,3-Butadieneof 17.00,394,6894,549,899,5910,06
1,2-Butadiene0,0030,080,10,010,15
1-butyn0,010,280,0020,0010,04
Butenin0,030,960,0010,001
Quantity, kg/h200,0164,6 35,435,420,233,222,0

EXAMPLE 10

Perform isolation and purification of 1,3-butadiene from C4-fractions of pyrolysis according to figure 3. Of the dotted lines use lines 2A, 9b and 15A.

Source4-faction supplied in quantities of 100 kg/h, has a composition close to that specified for the stream 1 in table 1. Unlike the indicated concentration of 1,3-butadiene in the source4-faction is 42.9%, the concentration of 1,2-butadiene (metalalloy) - 0,3%.

Preliminary rectification is carried out in column K-1 efficiency 70 teoretisk. From it derive 88,3 kg/h of distillate containing 48.3% of 1,3-butadiene, 29.2% of isobutene, 15.2% of 1-butene, 1,2% 2-butenes, 4.5% of butane, 0.1% of propene 0.01% of 1,2-butadiene, 0.01% of 1-butane and 0.9% Butenin, and also deduce 11.7 kg/h VAT residue containing 81,0% 2-butenes, 11,1% nbutane, 2,4% 1,3-butadiene, 2,5% 1,2-butadiene, 1.7% of 1-butyne, 0,5% Butenin. Essentially, what kubovy balance output 2-butenes, which facilitates the subsequent extractive distillation, 1-butyn that hereroense in zones G-1 and G-2, much worse Butenin, and 1,2-butadiene.

The distillate in line 1 and 1A are served in the area ER. As extractant using acetonitrile with 4% water and inhibitors of polymerization and hydrolysis. Submission to the ER on line 3 is 320 kg/h (compared to 400 kg/h in example 1), the concentration of the extractant in the liquid in the middle part of the ER is 70%.

In zone G irrigation type (corresponds to G-2 in figure 1) using the catalyst Nickel (25%) aluminum oxide", keep the temperature 10-20°and a pressure of 4.0 to 4.5 ATA.

The final rectification of the flow after the hydrogenation is carried out in the column K-2 with the output of the target product on line 15A.

As a result of 100 kg/h source4-faction get a 41.9 kg/h commercial product containing 99,24% 1,3-butadiene, 0.7% of 2-butenes, 0,05% nbutane, 0,002% α-acetylene hydrocarbons, 0.01% of 1,2-butadiene.

1. The method of extraction and purification of 1,3-butadiene from C4-fraction of hydrocarbons containing butadiene(s), butenes, butane(s), acetylene hydrocarbons and possibly a small amount of hydrocarbons With3and C5using process flow diagrams, including at least the area of extractive distillation in the presence of a polar extractant with the conclusion in the distillate mainly butenes and butane(s), zone desorption from the extractant stream containing predominantly 1,3-butadiene and mixtures of at least 2-butene(s) and acetylene hydrocarbons, and possibly also including the area(s) of the distillation stream containing predominantly 1,3-butadiene, wherein the specified stream containing predominantly 1,3-butadiene and these impurities, conduct liquid-phase selective hydrogenation mainly α-AC is Milanovich hydrocarbons in the presence of a solid catalyst, containing the metal(s), with(e) high activity in the hydrogenation, preferably base(s) metal(s) on a solid carrier, and the support temperature in the range from 5°C to 75°and the supply of hydrogen or hydrogen-containing gas mixture and the contact time so that the hydrogenation is subjected to no more than 6%, preferably not more than 2% contained butadiene, and perhaps after a specified hydrogenation of 1,3-butadiene is additionally separated from impurities by distillation.

2. The method according to claim 1 in which the hydrogenation α-acetylene hydrocarbons in the specified stream containing predominantly 1,3-butadiene, preferably using a catalyst containing Nickel and/or copper and/or cobalt and/or molybdenum on a solid medium.

3. The method according to claim 1, wherein spend two-stage liquid-phase hydrogenation α-acetylene hydrocarbons: original partial hydrogenation in the source4-faction to a residual content α-acetylene hydrocarbons not more than 0.5% and finally selected after extractive distillation in a stream containing predominantly 1,3-butadiene and these impurities, to a residual content α-acetylene hydrocarbons not more than 0.02%, preferably not more than 0.005%.

4. The method according to claim 1, wherein when the content in the source4-faction is m ore than 8% of isobutene for hydrogenation α -acetylene hydrocarbons, it is preferable to use a catalyst containing palladium on a solid medium.

5. The method according to claim 1, in which area(s) of hydrogenation with the catalyst support completed(s) liquid hydrocarbons, and a hydrogen-containing stream is served from the bottom through the distribution(s) device(s) or area(s) of hydrogenation with a catalyst irrigate liquid hydrocarbons through the top of the distribution(s) device(s) so that it remains free gas communication between the cross section area of the hydrogenation, the hydrogen source is attached to the hydrogenation zone at one or more points and the depth of hydrogenation regulate by maintaining the necessary partial pressure of hydrogen and temperature.

6. The method according to claim 1, in which a stream containing predominantly 1,3-butadiene and these impurities before cleaning the hydrogenation is separated from the impurities of the extractant and possibly other non-hydrocarbonaceous impurities by water washing and/or additional rectification.

7. The method according to claim 1, in which after hydrogenation α-acetylene hydrocarbon stream containing predominantly 1,3-butadiene, carry out rectification and distillate output stream containing the formed 1-butene, partially 1,3-butadiene boiling impurities and possibly nbutane, which preferably recirc leraut in the specified area of extractive distillation, and output VAT residue, containing predominantly 1,3-butadiene.

8. The method according to claim 1, in which a stream containing predominantly 1,3-butadiene and partially impurities, possibly after distillation of the stream containing 1-butene, partially 1,3-butadiene and low-boiling impurities, is subjected to further distillation from the more high-boiling impurities as distillate output commodity 1,3-butadiene.

9. The method according to claim 1, wherein when the distillation of 1,3-butadiene from the more high-boiling impurities from the comprehensive part of this distillation zone output side stream containing 2-butenes and partially 1,3-butadiene, which is preferably returned to the extractive distillation zone, and in the composition of the cubic residue deduce 1,2-butadiene.

10. The method according to claim 1, in which a stream containing predominantly 1,3-butadiene and partially impurities, after purification by hydrogenation is subjected to rectification in the area, with the output side of the stream, as distillate output stream containing 1-butene, partially 1,3-butadiene and impurities, as VAT residue remove impurities boiling above 1,3-butadiene, and as a side stream output commodity 1,3-butadiene.

11. The method according to claim 1, wherein the source With4-fraction hydrocarbons before serving extractive rectification or her previous partial hydrogenation α-zelenovic hydrocarbons is subjected to rectification and her separate thread(s), contains(e) heavy components with a boiling point above 1,3-butadiene.

12. The method according to claim 11, wherein when the specified rectification as VAT residue derive mainly present in the original4-fraction components with boiling points above 20°including hydrocarbons with the number of carbon atoms of more than 4 and you may polymerization inhibitors and corrosion.

13. The method according to claim 11, wherein when the specified rectification as specified VAT residue or side selection output stream containing a significant portion present in the original4-hydrocarbon fractions With4with temperatures above minus 1°C, preferably above 4°S, which can be further subjected to hydrogenation to obtain additional quantity of 1,3-butadiene.



 

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