INTEGRATED SYSTEMS AND METHODS FOR PRODUCING 1,3-BUTADIENE VIA EXTRACTIVE DISTILLATION, DISTILLATION, AND/OR SELECTIVE HYDROGENATION
20220267234 · 2022-08-25
Assignee
Inventors
Cpc classification
International classification
Abstract
Systems and methods for producing 1,3-butadiene from a C.sub.4 hydrocarbon mixture are disclosed. The C.sub.4 hydrocarbon mixture comprising 1,3-butadiene, C.sub.4 acetylenes, and other C.sub.4 hydrocarbons is processed in an extractive distillation column to produce a crude 1,3-butadiene stream that comprises 1,3-butadiene, and C.sub.4 acetylenes including vinyl acetylene and ethyl acetylene. The crude 1,3-butadiene stream is subsequently distilled in the first distillation column, and the bottom stream of the first distillation column is further distilled in a second distillation column to produce an overhead stream comprising primarily 1,3-butadiene. A side stream comprising primarily C.sub.4 acetylenes is withdrawn from the second distillation column and processed in a selective hydrogenation unit to produce additional 1,3-butadiene.
Claims
1. A method of producing 1,3 butadiene, the method comprising: extractive distilling of a C.sub.4 hydrocarbon feed to form a crude butadiene stream comprising 1,3 butadiene and one or more C.sub.4 acetylenes; distilling, by one or more distillation columns, the crude butadiene stream; withdrawing, from the one or more distillation columns, a side stream comprising primarily the one or more C.sub.4 acetylenes; and hydrogenating at least some of the C.sub.4 acetylene of the side stream to produce 1,3 butadiene in a product stream.
2. The method of claim 1, wherein the C.sub.4 hydrocarbon feed comprises one or more butanes, 1,2-butadiene, 1,3-butadiene, vinyl acetylene, and ethyl acetylene and C.sub.5+ hydrocarbons.
3. The method of claim 2, wherein the C.sub.4 hydrocarbon feed stream comprises 0.1 to 10 wt. % butane, 5 to 35 wt. % isobutene, 5 to 35 wt. % 1-butene, 1 to 15 wt. % 2-butenes, 0.01 to 5 wt. % methyl acetylene, 0.01 to 5 wt. % 1,2 butadiene, 25 to 60 wt. % 1,3 butadiene, 0.1 to 10 wt. % vinyl acetylene, and 0.1 to 10 wt. % ethyl acetylene.
4. The method of claim 1, wherein the C.sub.4 acetylene includes vinyl acetylene and/or ethyl acetylene and the crude butadiene stream further comprises 2-butenes, methyl acetylene, 1,2-butadiene, C.sub.5+ hydrocarbons, or combinations thereof.
5. The method of claim 1, wherein the hydrogenating step includes selective hydrogenation of the vinyl acetylene and/or ethyl acetylene.
6. The method of claim 1, wherein the distilling step comprises: distilling, in a first distillation column, the crude butadiene stream to form a first overhead stream comprising primarily methyl acetylene and a first bottom stream comprising 1,3-butadiene, vinyl acetylene, ethyl acetylene, C.sub.5 hydrocarbons, C.sub.5+ hydrocarbons, or combinations thereof; and distilling, in a second distillation column, the first bottom stream to produce a second overhead stream comprising primarily 1,3 butadiene and second bottom stream comprising primarily C.sub.5+ hydrocarbons.
7. The method of claim 6, wherein the side stream is withdrawn from the second distillation column.
8. The method of claim 6, wherein the first distillation column is operated at an overhead boiling range of 25 to 45° C., and a reboiler range of 40 to 70° C.
9. The method of claim 6, wherein the first distillation column is operated at an operating pressure in a range of 3 to 8 bara.
10. The method of claim 6, wherein the second distillation column is operated at an overhead boiling range of 25 to 45° C., and a reboiler range of 40 to 70° C.
11. The method of claim 6, wherein the second distillation column is operated at an operating pressure in a range of 3 to 8 bar.
12. The method of claim 6, further comprising flowing the product stream produced in the hydrogenating step to the second distillation column.
13. The method of claim 1, wherein the extractive-distilling is carried out at an overhead boiling range of 25 to 45° C. and re-boiler range of 120 to 250° C.
14. The method of claim 1, wherein the extractive-distilling is carried out at an operating pressure of 5 to 10 bara.
15. The method of claim 1, wherein the extractive-distilling is carried out using a solvent selected from the group comprising DMF, NMP, CAN, and combinations thereof.
16. The method of claim 1, wherein the hydrogenating is conducted at a reaction temperature of 50 to 200° C.
17. The method of claim 1, wherein the hydrogenating is conducted at an operating pressure of 5 to 25 bar.
18. The method of claim 1, wherein the hydrogenating is conducted at a weight hourly space velocity in a range of 5 to 30 hr.sup.−1.
19. The method of claim 1, wherein the hydrogenating is conducted in presence of a catalyst selected from the group consisting of Pd on alumina, Pt, Mn, Ni, Ag, and combinations thereof.
20. The method of claim 4, wherein the hydrogenating is conducted in presence of a catalyst selected from the group consisting of Pd on alumina, Pt, Mn, Ni, Ag, and combinations thereof.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] For a more complete understanding, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
[0024]
[0025]
DETAILED DESCRIPTION OF THE INVENTION
[0026] Currently, a conventional method of producing 1,3-butadiene from a C.sub.4 hydrocarbon mixture produced by a steam cracker includes two extractive distillation steps, in which the first extractive distillation step includes separating the C.sub.4 hydrocarbon stream into (1) an effluent comprising butadiene and C.sub.4 acetylenes and (2) a stream comprising other C.sub.4 hydrocarbons and the second extractive distillation step includes separating the effluent stream into a 1,3-butadiene stream and a C.sub.4 acetylene stream. The conventional two step extractive distillation steps require high capital expenditure, materials, and energy costs. Additionally, the C.sub.4 acetylene is not fully utilized for producing 1,3-butadiene, resulting in low production efficiency. The present invention provides a solution to at least some of these problems. The solution is premised on a method of producing 1,3-butadiene that comprises one extractive distillation step followed by a distillation step and a selective hydrogenation step. By eliminating one of the extractive distillation steps, the discovered method is capable of reducing the capital expenditure, materials, and energy costs for producing 1,3-butadiene compared to the conventional methods. Furthermore, the discovered method produces additional 1,3-butadiene via selectively hydrogenating C.sub.4 acetylene separated from the distillation step, resulting in increased production efficiency for 1,3-butadiene compared to the conventional methods. These and other non-limiting aspects of the present invention are discussed in further detail in the following sections.
A. System for Producing 1,3-Butadiene
[0027] In embodiments of the invention, the system for producing 1,3-butadiene includes an extractive distillation column, one or more distillation columns, and a selective hydrogenation unit. With reference to
[0028] In embodiments of the invention, extractive distillation column 101 is configured to receive solvent stream 11 and C.sub.4 hydrocarbon feed stream 12 comprising C.sub.4 hydrocarbons therein. Extractive distillation column 101 is further configured to separate C.sub.4 hydrocarbon feed stream 12 to produce first effluent stream 14 and first raffinate stream 13. According to embodiments of the invention, solvent stream 11 comprises a solvent including dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP), acetonitrile (ACN), or combinations thereof. C.sub.4 hydrocarbon feed stream 12 may comprise n-butane, isobutane, isobutylene, 1-butene, 2-butenes, 1,3-butadiene, 1,2-butadiene, C.sub.4 acetylenes, or combinations thereof. C.sub.4 hydrocarbon feed stream 12 may further comprise methyl acetylene, C.sub.5+ hydrocarbons, or combinations thereof. The C.sub.4 acetylenes may include vinyl acetylene and/or ethyl acetylene. In embodiments of the invention, first effluent stream 14 is a bottom stream from extractive distillation column 101. First effluent stream 14 may comprise primarily the solvent, 1,3-butadiene, 1,2-butadiene, and C.sub.4 acetylenes, collectively. First raffinate stream 13 may comprise n-butane, isobutane, isobutylene, 1-butene, 2-butene, and combinations thereof. In embodiments of the invention, solvent stream 11 is flowed into extractive distillation column 101 through an inlet disposed on upper half of extractive distillation column 101. In embodiments of the invention, C.sub.4 hydrocarbon feed stream 12 is flowed into extractive distillation column 101 through an inlet disposed on lower half of extractive distillation column 101.
[0029] In embodiments of the invention, a bottom outlet of extractive distillation column 101 is in fluid communication with an inlet of solvent recovery unit 102 such that first effluent stream 14 flows from extractive distillation column 101 to solvent recovery unit 102. According to embodiments of the invention, solvent recovery unit 102 is configured to separate first effluent stream 14 to produce recovered solvent stream 15 and crude butadiene stream 16. In embodiments of the invention, recovered solvent stream 15 is a bottom stream from solvent recovery unit 102. Recovered solvent stream 15 comprises primarily the solvent. In embodiments of the invention, crude butadiene stream 16 comprises primarily 1,3-butadiene, C.sub.4 acetylenes (vinyl acetylene and ethyl acetylene), collectively. Crude butadiene stream 16 may further include 2-butenes, methyl acetylene, 1,2-butadiene, C.sub.5+ hydrocarbons, or combinations thereof. According to embodiments of the invention, solvent recovery unit 102 includes one or more distillation columns, one or more heat exchangers, one or more boil-off vessels, or combinations thereof.
[0030] According to embodiments of the invention, a top outlet of solvent recovery unit 102 is in fluid communication with first distillation column 103 such that crude butadiene stream 16 flows from solvent recovery unit 102 to first distillation column 103. In embodiments of the invention, first distillation column 103 is configured to separate crude butadiene stream 16 to form first overhead stream 17 and first bottom stream 18. In embodiments of the invention, first overhead stream 17 comprises methyl acetylene. First bottom stream 18 may comprise 1,3-butadiene, the C.sub.4 acetylenes (vinyl acetylene and ethyl acetylene), C.sub.5+ hydrocarbons, or combinations thereof.
[0031] According to embodiments of the invention, a bottom outlet of first distillation column 103 is in fluid communication with an inlet of second distillation column 104 such that first bottom stream 18 flows from first distillation column 103 to second distillation column 104. In embodiments of the invention, second distillation column 104 is configured to separate first bottom stream 18 to form second overhead stream 19 and second bottom stream 20. In embodiments of the invention, second overhead stream 19 comprises primarily 1,3-butadiene. Second bottom stream 20 comprises primarily C.sub.5+ hydrocarbons. In embodiments of the invention, second distillation column 104 is further configured to form side stream 21 comprising primarily the C.sub.4 acetylenes, collectively, including vinyl acetylene and ethyl acetylene.
[0032] According to embodiments of the invention, a side outlet of second distillation column 104 is in fluid communication with selective hydrogenation unit 105 such that side stream 21 flows from second distillation column 104 to selective hydrogenation unit 105. In embodiments of the invention, the side outlet of second distillation column 104 is located at 0 to 50% of total theoretical plate number of second distillation column counting from the bottom.
[0033] In embodiments of the invention, selective hydrogenation unit 105 is configured to selectively hydrogenate the C.sub.4 acetylenes of side stream 21 to produce additional 1,3-butadiene stream 22 (a product stream) comprising primarily 1,3-butadiene and second raffinate stream 23 comprising C.sub.5 to C.sub.8 hydrocarbons. According to embodiments of the invention, selective hydrogenation unit 105 comprises one or more selective hydrogenation reactors and one or more separators (e.g., distillation columns). The one or more selective hydrogenation reactors may be configured to selectively hydrogenate the C.sub.4 acetylenes of side stream 21 and produce a reactor effluent stream comprising 1,3-butadiene. The one or more separators may be configured to separate the reactor effluent stream to form additional 1,3-butadiene stream 22 and second raffinate stream 23. In embodiments of the invention, selective hydrogenation unit 105 includes a catalyst comprising Pd, Pt, Al.sub.2O.sub.3, Mn, Ni, Ag, or combinations thereof. In embodiments of the invention, selective hydrogenation unit 105 includes one or more fixed bed reactors. In embodiments of the invention, a first outlet of selective hydrogenation unit 105 is in fluid communication with an inlet of second distillation column 104 such that 1,3-butadiene stream 22 flows from selective hydrogenation unit 105 to second distillation column 104. In embodiments of the invention, second raffinate stream 23 is combined with second bottom stream 20 to form third raffinate stream 24. In embodiments of the invention, third raffinate stream 24 comprises 2-butenes, 1,2-butadiene, C.sub.5 to C.sub.8 hydrocarbons, or combinations thereof.
B. Method of Producing 1,3-butadiene
[0034] Methods of producing 1,3-butadiene from a C.sub.4 hydrocarbon feed stream have been discovered. Embodiments of the method are capable of reducing the production costs and capital expenditure for producing 1,3-butadiene compared to conventional methods. As shown in
[0035] According to embodiments of the invention, as shown in block 201, method 200 includes extractive distilling of C.sub.4 hydrocarbon feed stream 12 to form crude butadiene stream 16 comprising primarily 1,3-butadiene, and C.sub.4 acetylenes, collectively, including vinyl acetylene and ethyl acetylene. In embodiments of the invention, C.sub.4 hydrocarbon feed stream 12 comprises 0.1 to 10 wt. % butanes, 5 to 35 isobutene, 5 to 35 wt. % 1-butene, 1 to 15 wt. % 2-butenes, 0.01 to 5 wt. % methyl acetylene, 0.01 to 5 wt. % 1,2 butadiene, 25 to 60 wt. % 1,3 butadiene, 0.1 to 10 wt. % vinyl acetylene, and 0.1 to 10 wt. % ethyl acetylene. In embodiments of the invention, C.sub.4 hydrocarbon feed stream 12 includes a C.sub.4 hydrocarbon stream separated from an effluent of a steam cracking unit.
[0036] In embodiments of the invention, the extractive-distilling at block 201 includes flowing solvent stream 11 and C.sub.4 hydrocarbon feed stream 12 to extractive distillation column 101 under operating conditions sufficient to produce first raffinate stream 13 and first effluent stream 14. The extractive-distilling at block 201 further includes separating first effluent stream 14 in solvent recovery unit 102 to produce recovered solvent stream 15 and crude butadiene stream 16. According to embodiments of the invention, solvent stream 11 and C.sub.4 hydrocarbon feed stream 12 have a flowrate ratio in a range of 5 to 10 and all ranges and values there between including ranges of 5 to 6, 6 to 7, 7 to 8, 8 to 9, and 9 to 10. In embodiments of the invention, solvent stream 11 is flowed into an upper half portion of extractive distillation column 101. C.sub.4 hydrocarbon feed stream 12 may be flowed into a lower half portion of extractive distillation column 101. In embodiments of the invention, extractive distillation column 101 is operated at an overhead boiling range of 25 to 45° C. and all ranges and values there between including ranges of 25 to 27° C., 27 to 29° C., 29 to 31° C., 31 to 33° C., 33 to 35° C., 35 to 37° C., 37 to 39° C., 39 to 41° C., 41 to 43° C., and 43 to 45° C. Extractive distillation column 101 may be operated at a reboiler range of 120 to 250° C. and all ranges and values there between including ranges of 120 to 130° C., 130 to 140° C., 140 to 150° C., 150 to 160° C., 160 to 170° C., 170 to 180° C., 180 to 190° C., 190 to 200° C., 200 to 210° C., 210 to 220° C., 220 to 230° C., 230 to 240° C., and 240 to 250° C. Extractive distillation column 101 may be operated at an operating pressure of 5 to 10 bara and all ranges and values there between including ranges of 5 to 5.5 bara, 5.5 to 6 bara, 6 to 6.5 bara, 6.5 to 7 bara, 7 to 7.5 bara, 7.5 to 8 bara, 8 to 8.5 bara, 8.5 to 9 bara, 9 to 9.5 bara, and 9.5 to 10 bara.
[0037] In embodiments of the invention, first effluent stream 14 comprises 10 to 35 wt. % 1,3-butadiene, 0.1 to 2 wt. % C.sub.4 acetylenes, and 60 to 90 wt. % of the solvent. In embodiments of the invention, solvent recovery unit 102 is a distillation column. Solvent recovery unit 102 may be operated at an overhead boiling range of 40 to 100° C. and all ranges and values there between including ranges of 40 to 50° C., 50 to 60° C., 60 to 70° C., 70 to 80° C., 80 to 90° C., and 90 to 100° C. Solvent recovery unit 102 may be operated at a reboiler range of 120 to 300° C. and all ranges and values there between including ranges of 120 to 130° C., 130 to 140° C., 140to 150° C., 150 to 160° C., 160 to 170° C., 170 to 180° C., 180 to 190° C., 190 to 200° C., 200 to 210° C., 210 to 220° C., 220 to 230° C., 230 to 240° C., 240 to 250° C., 250 to 260° C., 260 to 270° C., 270 to 280° C., 280 to 290° C., and 290 to 300° C. Solvent recovery unit 102 may be operated at an operating pressure of 1.2 to 8 bar and all ranges and values there between including ranges of 1.2 to 2.0 bar, 2.0 to 3.0 bar, 3.0 to 4.0 bar, 4.0 to 5.0 bar, 5.0 to 6.0 bar, 6.0 to 7.0 bar, and 7.0 to 8.0 bar. Crude butadiene stream 16 may comprise 85 to 95 wt. % 1,3-butadiene and 5 to 15 wt. % C.sub.4 acetylenes. Crude butadiene stream 16 may further comprise 0.1 to 1 wt. % 2-butenes, 0.01 to 0.1 wt. % methyl acetylene, 0.01 to 0.05 wt. % 1,2-butadiene, and 0.1 to 1 wt. % C.sub.5+ hydrocarbons According to embodiments of the invention, recovered solvent stream 15 can be recycled to extractive distillation column 101.
[0038] According to embodiments of the invention, as shown in block 202, method 200 comprises distilling, in first distillation column 103, crude butadiene stream 16 to form first overhead stream 17 and first bottom stream 18. First overhead stream 17 may comprise primarily methyl acetylene. First bottom stream 18 may comprise 85 to 95 wt. % 1,3-butadiene, 5 to 15 wt. % C.sub.4 acetylenes including 3 to 12 wt. % vinyl acetylene and 2 to 3 wt. % ethyl acetylene. First bottom stream 18 may further include C.sub.5+ hydrocarbons. In embodiments of the invention, first distillation column 103 is operated at an overhead boiling range of 25 to 45° C. and all ranges and values there between including ranges of 25 to 27° C., 27 to 29° C., 29 to 31° C., 31 to 33° C., 33 to 35° C., 35 to 37° C., 37 to 39° C., 39 to 41° C., 41 to 43° C., and 43 to 45° C. First distillation column 103 may be operated at a reboiler range of 40 to 70° C. and all ranges and values there between. First distillation column 103 may be operated at an operating pressure of 3 to 8 bara and all ranges and values there between including ranges of 3 to 3.5 bara, 3.5 to 4 bara, 4 to 4.5 bara, 4.5 to 5 bara, 5 to 5.5 bara, 5.5 to 6 bara, 6 to 6.5 bara, 6.5 to 7 bara, 7 to 7.5 bara, and 7.5 to 8 bara.
[0039] According to embodiments of the invention, as shown in block 203, method 200 comprises distilling, in second distillation column 104, first bottom stream 18 to produce second overhead stream 19 and second bottom stream 20. In embodiments of the invention, second overhead stream 19 includes 99.50 to 99.95 wt. % 1,3-butadiene and all ranges and values there between. Second bottom stream 20 may include primarily C.sub.5+ hydrocarbons. In embodiments of the invention, second distillation column 104 is operated at an overhead boiling range of 25 to 45° C. and all ranges and values there between including ranges of 25 to 27° C., 27 to 29° C., 29 to 31° C., 31 to 33° C., 33 to 35° C., 35 to 37° C., 37 to 39° C., 39 to 41° C., 41 to 43° C., and 43 to 45° C. Second distillation column 104 may be operated at a reboiler range of 40 to 70° C. and all ranges and values there between including ranges of 40 to 42° C., 42 to 44° C., 44 to 46° C., 46 to 48° C., 48 to 50° C., 50 to 52° C., 52 to 54° C., 54 to 56° C., 56 to 58° C., 58 to 60° C., 60 to 62° C., 62 to 64° C., 64 to 66° C., 66 to 68° C., and 68 to 70° C. Second distillation column 104 may be operated at an operating pressure of 3 to 8 bara and all ranges and values there between including ranges of 3 to 3.5 bara, 3.5 to 4 bara, 4 to 4.5 bara, 4.5 to 5 bara, 5 to 5.5 bara, 5.5 to 6 bara, 6 to 6.5 bara, 6.5 to 7 bara, 7 to 7.5 bara, and 7.5 to 8 bara.
[0040] According to embodiments of the invention, as shown in block 204, method 200 comprises withdrawing, from second distillation column 104, side stream 21 comprising primarily C.sub.4 acetylenes including vinyl acetylene, and/or ethyl acetylene. In embodiments of the invention, side stream 21 comprises 5 to 25 wt. % C.sub.4 acetylenes. In embodiments of the invention, at block 204, side stream 21 is withdrawn at 0 to 50% of total theoretical plate number of second distillation column 104 counting from bottom thereof. In embodiments of the invention, withdrawing of side stream 21 at block 204 is configured to avoid vinyl acetylene self-decomposition and/or explosion in second distillation column 104. In embodiments of the invention, a flowrate ratio between first bottom stream 18 and side stream 21 is in a range of 0.01 to 0.2 and all ranges and values there between including ranges of 0.01 to 0.02, 0.02 to 0.03, 0.03 to 0.04, 0.04 to 0.05, 0.05 to 0.06, 0.06 to 0.07, 0.07 to 0.08, 0.08 to 0.09, 0.09 to 0.10, 0.10 to 0.11, 0.11 to 0.12, 0.12 to 0.13, 0.13 to 0.14, 0.14 to 0.15, 0.15 to 0.16, 0.16 to 0.17, 0.17 to 0.18, 0.18 to 0.19, and 0.19 to 0.20.
[0041] According to embodiments of the invention, as shown in block 205, method 200 comprises selectively hydrogenating, in selective hydrogenation unit 105, at least some of the C.sub.4 acetylenes including the vinyl acetylene, and/or the ethyl acetylene of side stream 21 to produce additional 1,3-butadiene in a product stream (additional 1,3-butadiene stream 22). In embodiments of the invention, selectively hydrogenating at block 205 further produces second raffinate stream 23 comprising C.sub.5 to C.sub.8 hydrocarbons. In embodiments of the invention, additional 1,3-butadiene stream 22 comprises 85 to 99 wt. % 1,3-butadiene and all ranges and values there between including ranges of 85 to 87 wt. %, 87 to 89 wt. %, 89 to 91 wt. %, 91 to 93 wt. %, 93 to 95 wt. %, 95 to 97 wt. %, and 97 to 99 wt. %. In embodiments of the invention, at block 205, selective hydrogenation unit 105 is operated at a reaction temperature of 50 to 200° C. and all ranges and values there between including 50 to 60° C., 60 to 70° C., 70 to 80° C., 80 to 90° C., 90 to 100° C., 100 to 110° C., 110 to 120° C., 120 to 130° C., 130 to 140° C., 140 to 150° C., 150 to 160° C., 160 to 170° C., 170 to 180° C., 180 to 190° C., and 190 to 200° C. Selective hydrogenation unit 105 may be operated at a reaction pressure of 5 to 25 bara and all ranges and values there between including ranges of 5 to 6 bara, 6 to 7 bara, 7 to 8 bara, 8 to 9 bara, 9 to 10 bara, 10 to 11 bara, 11 to 12 bara, 12 to 13 bara, 13 to 14 bara, 14 to 15 bara, 15 to 16 bara, 16 to 17 bara, 17 to 18 bara, 18 to 19 bara, 19 to 20 bara, 20 to 21 bara, 21 to 22 bara, 22 to 23 bara, 23 to 24 bara, and 24 to 25 bara. In embodiments of the invention, additional 1,3-butadiene stream 22 (a product stream) is flowed back to second distillation column 104. Additional 1,3-butadiene stream 22 may be separated in second distillation column 104 to produce additional 1,3-butadiene stream 22 in second overhead stream 19. In embodiments of the invention, second raffinate stream 23 may be combined with second bottom stream 20 to form third raffinate stream 24 comprising primarily C.sub.5+ hydrocarbons.
[0042] Although embodiments of the present invention have been described with reference to blocks of
[0043] In the context of the present invention, at least the following 19 embodiments are described. Embodiment 1 is a method of producing 1,3 butadiene. The method includes extractive distilling of a C.sub.4 hydrocarbon feed to form a crude butadiene stream containing 1,3 butadiene and one or more C.sub.4 acetylenes. The method further includes distilling, by one or more distillation columns, the crude butadiene stream. The method still further includes withdrawing, from the one or more distillation columns, a side stream containing primarily the one or more C.sub.4 acetylenes. The method also includes hydrogenating at least some of the C.sub.4 acetylene of the side stream to produce 1,3 butadiene in a product stream. Embodiment 2 is the method of embodiment 1, wherein the C.sub.4 hydrocarbon feed contains one or more butanes, 1,2-butadiene, 1,3-butadiene, vinyl acetylene, and ethyl acetylene and C.sub.5+ hydrocarbons. Embodiment 2 is the method of embodiment 2, wherein the C.sub.4 hydrocarbon feed stream contains 0.1 to 10 wt. % butane, 5 to 35 wt. % isobutene, 5 to 35 wt. % 1-butene, 1 to 15 wt. % 2-butenes, 0.01 to 5 wt. % methyl acetylene, 0.01 to 5 wt. % 1,2 butadiene, 25 to 60 wt. % 1,3 butadiene, 0.1 to 10 wt. % vinyl acetylene, and 0.1 to 10 wt. % ethyl acetylene. Embodiment 4 is the method of any of embodiments 1 to 3, wherein the C.sub.4 acetylene includes vinyl acetylene and/or ethyl acetylene and the crude butadiene stream further contains 2-butenes, methyl acetylene, 1,2-butadiene, C.sub.5+ hydrocarbons, or combinations thereof. Embodiment 5 is the method of any of embodiments 1 to 4, wherein the hydrogenating step includes selective hydrogenation of the vinyl acetylene and/or ethyl acetylene. Embodiment 6 is the method of any of embodiments 1 to 5, wherein the distilling step includes distilling, in a first distillation column, the crude butadiene stream to form a first overhead stream containing primarily methyl acetylene and a first bottom stream containing 1,3-butadiene, vinyl acetylene, ethyl acetylene, C.sub.5 hydrocarbons, C.sub.5+ hydrocarbons, or combinations thereof. The method further includes distilling, in a second distillation column, the first bottom stream to produce a second overhead stream containing primarily 1,3 butadiene and second bottom stream containing primarily C.sub.5+ hydrocarbons. Embodiment 7 is the method of embodiment 6, wherein the side stream is withdrawn from the second distillation column. Embodiment 8 is the method of either of embodiments 6 or 7, wherein the first distillation column is operated at an overhead boiling range of 25 to 45° C., and a reboiler range of 40 to 70° C. Embodiment 9 is the method of any of embodiments 6 to 8, wherein the first distillation column is operated at an operating pressure in a range of 3 to 8 bara. Embodiment 10 is the method of any of embodiments 6 to 9, wherein the second distillation column is operated at an overhead boiling range of 25 to 45° C., and a reboiler range of 40 to 70° C. Embodiment 11 is the method of any of embodiments 6 to 10, wherein the second distillation column is operated at an operating pressure in a range of 3 to 8 bar. Embodiment 12 is the method of any of embodiments 6 to 11, further including flowing the product stream produced in the hydrogenating step to the second distillation column. Embodiment 13 is the method of any of embodiments 1 to 12, wherein the extractive-distilling is carried out at an overhead boiling range of 25 to 45° C. and re-boiler range of 120 to 250° C. Embodiment 14 is the method of any of embodiments 1 to 13, wherein the extractive-distilling is carried out at an operating pressure of 5 to 10 bara. Embodiment 15 is the method of any of embodiments 1 to 14, wherein the extractive-distilling is carried out using a solvent selected from the group including DMF, NMP, CAN, and combinations thereof. Embodiment 16 is the method of any of embodiments 1 to 15, wherein the hydrogenating is conducted at a reaction temperature of 50 to 200° C. Embodiment 17 is the method of any of embodiments 1 to 16 wherein the hydrogenating is conducted at an operating pressure of 5 to 25 bar. Embodiment 18 is the method of any of embodiments 1 to 17, wherein the hydrogenating is conducted at a weight hourly space velocity in a range of 5 to 30 hr.sup.−1. Embodiment 19 is the method of any of embodiments 1 to 18, wherein the hydrogenating is conducted in presence of a catalyst selected from the group consisting of Pd on alumina, Pt, Mn, Ni, Ag, and combinations thereof.
[0044] Although embodiments of the present application and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the embodiments as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the above disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.