The method of separation of the contact gas dehydrogenation butanebutylene mixtures
(57) Abstract:Usage: in the petrochemical industry. The essence of the invention: method of separation of the contact gas dehydrogenation of butane-butylene mixtures enables selection of a butane-butylene-butadiene fraction, its extractive distillation in the presence of acetonitrile to obtain nextdaysomany butane-butylene fraction returned in the dehydrogenation process, and the extract containing butadiene, rectification extract with obtaining butadiene raw, clear rectification to obtain the desired butadiene and VAT residue. Moreover, the VAT residue clear rectification return in column a clear rectification in the reflux line of the latter, without prior washing. 2 Il. The invention relates to the petrochemical industry, namely to obtain butadiene by extracting gas from the contact dehydrogenation of butane-butyl mixtures.A known method of producing butadiene extraction of the contact gas dehydrogenation, consisting in the allocation of butane-butylene-butadiene fraction in the column pre-rectification, submitting it to the extractive rectification, the return nextpage the rigid rectification and submission of VAT residue water washing from the extractant with further, washed from the extractant in the supply line of the column pre-rectification  Method allows you to retrieve up to 93 wt. butadiene gas from the contact, which is not enough.The goal of the proposed method increases the degree of extraction of butadiene from the contact gas dehydrogenation of butane-butylene mixtures.The objective is achieved by changing the process technology division contact gas by separating the butane-butylene-butadiene fraction (BBF) in the column pre-rectification, feed her on extractive rectification, return nextdaysomany faction in the dehydrogenation process, the selection of the extract butadiene raw, clear rectification and submission of VAT residue in the reflux line of the column pre-rectification.A distinctive feature of the proposed method is the exclusion from the scheme of the column of water washing VAT residue clear distillation of butadiene raw and the return of the VAT residue in the reflux line of the column pre-rectification, and not in her power (see schemes 1 and 2 in Fig. 1 and 2).Example 1 (the prototype). Setup subjected to dehydrogenation dehydrogenation mixture fresh is 1) composition, wt. H21,2; total hydrocarbons1-C36,1; isobutylene + isobutane 1,2; n-butylene 26,5; butadiene 13,0); the amount of hydrocarbons WITH5and above 2.0; n-butane else.Received contact the gas is subjected to separation according to scheme 1 by rectification in CT-2 emitting 168,2 t/h butane-butylene butylene fraction (stream 2) composition, wt. hydrocarbons WITH2-C30,04; isobutane + isobutylene 1,25; n-butylene 29,07; butadiene 13,73; hydrocarbons5and up to 0.12; n-butane else.Received BBBF served on extractive rectification in CT 20/1; not extracted butane-butylene fraction washed with water from acetonitrile in the CT-150 and returned to the dehydrogenation (stream 3) number 138 t/h composition, wt. isobutane-isobutylene 1,61; n-butylene 32,96; butadiene 0,16; the amount of the hydrocarbon WITH5and up to 0.03; n-butane else.From the extractant in CT-20/P-30 produce butadiene raw, put it first distillation cleared from the lungs in CT-50, then storable in CT 56 hydrocarbons and get 23,0 t/HR of butadiene concentrate with a content of butadiene to 99.5 wt. the rest of the butylenes.VAT product of the distillation of butadiene from high-boiling hydrocarbons washed with water in CT a and the number is rasaut in the power of the column pre-rectification CT-2.The degree of extraction of butadiene from the contact strip of 93.5 wt.Example 2. At the same dehydrogenation as in example 1, is subjected to dehydrogenation mixture of fresh n-butane (52 t/h) and recycle butane-butylene fraction (138 t/h).Get 1 88 t/h contact gas (stream 1), wt. H21.3; total hydrocarbons1-C36,3; isobutylene + isobutane 1,1; n-butylene 27,5; butadiene 13,6); the amount of hydrocarbon, C5and up to 1.9; n-butane else.Received contact the gas is subjected to separation according to scheme 2 by rectification in the column 2 with the release 169,0 t/h BBBF (stream 2) composition, wt. hydrocarbons, C2-C30.05; isobutane + isobutylene 1.27mm; n-butylene 29,85; butadiene 14,98; hydrocarbons5and above 1,14; acetonitrile 0,26; n-butane else.Received BBBF served on the extractive rectification column 3, nextdaytramadol butane-butylene fraction washed with water in column 7 and return to the dehydrogenation (stream 3) number 138 t/h composition, wt. isobutylene+isobutane 1.55V; n-butylene 3,69; butadiene 0,12; hydrocarbons WITH5and above 0,04 n-butane else.From the extractant in column 4 produce butadiene raw, put it first distillation purification from l content of butadiene to 99.5 wt. the rest of the butylenes.VAT product of the distillation of butadiene from high-boiling hydrocarbons in the amount of 2.0 t/h composition, wt. n-butylene 72,5; butadiene 2,5; hydrocarbons WITH5and higher than 3.0; acetonitrile 22,0 return in the reflux line of the column 2.The degree of extraction of butadiene from the contact gas is 96.5 wt.Thus, the proposed method of separation of the contact gas butane-butyl mixtures can increase the degree of extraction of butadiene from 93.5 wt. to 96.5 wt. In this case, also, removed the butane-butylene fraction in the same quantities as in the known method. The dehydrogenation extracted butane-butylene fraction in the mixture with fresh butane allows you to contact the gas with a content of butadiene is not less than the known method. The method of separation of the contact gas dehydrogenation of butane-butylene mixtures, including the allocation of butane-butylene-butadiene fraction in the pre-column distillation, extractive distillation of the butane-butylene-butadiene fraction in the presence as a solvent of acetonitrile with getting nextdaysomany butane-butylene fraction returned to the dehydrogenation process, and extract, sod target butadiene and VAT residue, refund of VAT residue clear rectification in the column pre-rectification, characterized in that the return VAT residue clear rectification directly served in the reflux line of the column pre-rectification.
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
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.
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.
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: 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: 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.
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: 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.
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