CA1104517A - Energy conservation in a butadiene process - Google Patents
Energy conservation in a butadiene processInfo
- Publication number
- CA1104517A CA1104517A CA283,881A CA283881A CA1104517A CA 1104517 A CA1104517 A CA 1104517A CA 283881 A CA283881 A CA 283881A CA 1104517 A CA1104517 A CA 1104517A
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- Canada
- Prior art keywords
- butadiene
- stream
- heat
- polar solvent
- per cent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C7/00—Purification; Separation; Use of additives
- C07C7/04—Purification; Separation; Use of additives by distillation
- C07C7/05—Purification; Separation; Use of additives by distillation with the aid of auxiliary compounds
- C07C7/08—Purification; Separation; Use of additives by distillation with the aid of auxiliary compounds by extractive distillation
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Analytical Chemistry (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Water Supply & Treatment (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
ENERGY CONSERVATION IN A BUTADIENE PROCESS
Abstract of the Disclosure A method is provided for the conservation of energy in a butadiene recovery and purification process in which part of the heat necessary for operation of the final buta-diene finishing column is obtained by heat exchange with the hot vapor of the polar solvent used in the extractive distil-lation of the butadiene, the heat being that obtained by condensation of the hot polar solvent vapor to liquid.
Abstract of the Disclosure A method is provided for the conservation of energy in a butadiene recovery and purification process in which part of the heat necessary for operation of the final buta-diene finishing column is obtained by heat exchange with the hot vapor of the polar solvent used in the extractive distil-lation of the butadiene, the heat being that obtained by condensation of the hot polar solvent vapor to liquid.
Description
5~
l'h~ in~e-rltic)il is cL-irected ~o a IlleelrLs o:E corlserv;.rlg energ~, especiall.y helt erler~,y, in a butadiene re~covery ancl puri fica.Lion -E!rocess ~ .
[t :is well kno~.n in the prior art that butadiene is ol~tainable by crackirlg of hi.~her molecul.lr weight hydrocarbolls or by dehydrogenatiorL of n-~uk~me or n-butenes and that the butadiene so produced is mixed with other hydrocarbons, typically i.ncludîng other CL~ hydrocarbons~ The mixture con-ta~nirg butadiene is not a~enable to slmple distilLation processes for the recovery of pure butadiene there~rom because of the simIlar vapor pressures of many of the compo-nents i`n the mixture. Thus, it has proved necessary to obtain pure butadîene by methods ot~er t'rLan simple d:istillation~ O~e met~Lod that has achieved consiclerable commercia:L acceptance is the use of an exkractive dlstiLlat:ion of the mixture in the presence of particular polar solvents, which polar solvents alter the volatility of certain co~ponents of the mixture such that a dîstillation process may be used~ Suitable polar solvenks include acetonItrile, dimethyl formamlde~ N-methyl .0 pyrrolidine, furfural, dimethyl acetamide, sulpholane and others~
By the selection OL suitable polar solve.nts fo~ an extractive distIllatlon, t~e miY~ture of butadiene and other C~ hydrocarbons ma~ be distilled to yield a butadiene rich stream because the presence o~ the polar solvent causæs th~
butanes a~l butenes present in the mixture to exhibit a higher volatillty permltting t~ei.r separatiorl by distillation from ~
the les,s volatile butadiene and acetylenes~ By silch an ex- ~ -tractî~Te d-istillation process~ the butanes and butenes are 3~ relnoved as an ovexLlead stream and th2 butadiene and ace~-~lenes .~ ~
are re~llovcd, toge~.iicr wit:h t:l~e polar ~Sol-ve~nt, a~ a ~otlo~ns Stl eal~ Thls l~ot~oms stream is ~.hen su~jecte~l to a stri.I)ping ::
~ste~ Jher~by the polar sol~ent is separat.ecL ~rorn the buta-diene y:ielcl:ing a vapor rich in butadielle and corltaining some ace~ylenes as :impurities~ Tllis vapor rlch in bu~adle~e i5 then condensed and fed to a fillaL butadielle fi.nishing column wl~ere it i.s dist~lled and butadien having a purity o~ at least 97 ~Teight per cent is obtained as an overhead -vapor~ ::
stream. T~is final butadiene finishing column requires a supply of heat for I~s operation~
The polar s-olvent separated ~rom the.butadiene and ~,. ~ . .
acetylenes in the stripp~ng step is subjected to purifica~
tion for re use in tl~e extractive dîstillation process~ This ~ ~ -puriEication may comprise a number of steps including removal of residual hydroc~rbons contained therein, washing with e.g~ :
~Jater and ~nally a distillation~ The distilLation of the polar solvent yields a product suitable ~or rec~cling to the : extractive d~stillation stage of th.e process~
For operation of~the final hutadiene finishing ~ -column, heat is suppl-ied ~y one or more rebollers attached :
~o the bottom of the column~ For t~e polar solvent distil- .;
lation, the majorit~ of the heat is supplied by dire~t addition of stea~ to the distillation col~mn~ -Because o~ the ne~d to be able to separate all t~e compon~nts~ as descri~ed above~ and to ~e able to conde~se, ~ :
where necessary, various ~ydrocarbon streams usin~ ambient - ~-temperature process w~ter rather than special relrigeration ~ -~
units, the temperatures and pressures witllin the whole : ~ process have to be carefully ~aianced - .if the pressure in a hydrocàrbon str~am is too low it ~ou:ld T~ di:Efi;cult to readily COnden~Se j ~. 'L~Lf~ ~7hO1e process :is fa:irly energ~ enSiV``
ancl~;litll tocZay's en.ergy costs any reclllctioIl o:E energy used in ~he process is highl,~ desira~le~
l~e have no~l discovered a met:hod o~ c.onserviny, heat:
energy in a butadiene reco~Jery .~nd pur.if:ication proc.ess wherein ~he heat obtained by tlle condensation of a hot vapor stream to a lîquid stream is used.to at least partly s~pply the heat necessary toopera-te a butadiene ~lnishincr column.
It is an O~JectiVe of this invention to provide an lmproved process Eor the recovery of butadiene Erom mixtures thereof with ot'~er C4 hyclrocarbons~ ~here-ln, a~ter separation o:E the butadiene from the other C~ hydrocarbons hy extractive distillation in the presenc:e o~ a polar solvent and subsequen-t separation oE the polar solvent to yield a b-utacl.lene enric'hed stream, the buta~iene enriched strea~ is Eed to a final ~u,a-diene finlshing column operated t.o ca,use the distilla~ior therein and separdtion of a stream containing:at least 97~10 butadiene-1,3, the improvement being the s~ply of at le~ast a portion o the heat necessary for the operation o.L said .-final butadiene finishing column by heat exchange of ~he contents o said finishing col~unn with a ~ot vapo: stream comprislng said polar solvent, said hea~ being essentially that obtained by the condensation o~ said hot ~rapor stream ,~ ' to a liquid stream. , l~herever used herein) ~utadiene means bu~adieI~e~
Reference is made to Figure 1 whlch rerc~res-ents a schemc-L-~ic flow diagram :Eor a process of th~ pri.or art and of the present invention.
In Figure 1, 1 is a Einal 'butadiene finls~lng column7 the impure butadi~ne being fed to it through l:i.rLe 2 ~ 5 ~ 7 T'ue pur:ified b.Lta~ .ne v~por is removed via l:Lne 3 ancl condensed (not sho~n~. Part of ~he liqui:Eied buta~iene is removed as hlgh purity b~l~adierle and th~ remainder i.s re:Eluxecl b~cl; by lln2 4 :into column l. The heat: to operate the finisllincr colulrlll l ;.s suppl-ied by circulating.the llcluld from the bottom of the column through two heat exchangers~ In the prior art, the llquld was fed ~y lî.nes 6 and 6A through . :~-:
heat e~changers 7 and 7A, being suppliecl with.steam throug'n : .
lines, 8 and 8A, and the heated liquid was returned to t~e lQ column by lines 9 and 9A~ : :
The distillation to~Jer 25 is used to purify the polar solvent used elsewhere in the process ~or the extractive . ~ ;
distilLation of butadiene (not sho~n~ The impur~ polar ~.
so~ent stream is fed to tower 25 by line 26. Steam îs ::~
supplied to the tower through lin.e 27. The liquid bottoms of the tower are removed through lîne 28 and a.re recycléd~`to other parts of the process~ The overhead vapor stream îs removed ~rom the tower through line 23 As în the prior art, ~ .
when valves l4 and 16 are closed and valve 17 is open~ the.
: 20 vapor is passed through the heat exchanger 1~ and cooIed by :
ambient temperature water :Eed through lîne 19~ l'he liquîd stream pa3ses from the exchanger 18 by line 20 and is then ~ed partly through line 22 ~ac~ înta the distillatîon tower 25 ~or reflux control purposes and partly through line 21 to the process for the extractîve distilla~ion of bukadiene ~not shown)~
In ~he process of the present invention, heat îs supplied to column 1 b~ cîrculatîng the llquid through lî`ne lO
to neat exchanger 11 and ~ack -to the cslumn ~ line 12~ :
Ad~itioIIal heat, as required, can be suppLiecL b~ one or b~th - 5 - :
o~ heat exchangers 7 and 7A being operated with elther no steam to one of 7 or 7A or reduced steam :flow to one of or bo~h o:E 7 or 7A. The heat to exchanger 11 is supplled by closing valve 17 and opening values 14 and 16 so that the hot polar solvent vapor passes through line 13 to heat e~changer 11 and back through line 15 as a hot liquid.
~epending on the conditions required in the process, the ho~ liquid stream in line 15 may or may not be further cooled in heat exchanger 18, cooling being controlled by whether or not ambient temperature water is fed through exchanger 18.
Thus, the present invention can be clearly seen as utilizing the heat available from the condensat-Lon o~
the hot polar solvent vapor to the liquid state. Heat available from urther cooling of the liquid polar solvent is very small compared to that for the change o:E state from vapor to liquid.
In an example of the process of the prior art, and with reference to Figure 1, approximately 18,000 pounds per hour of impure butadiene is fed by line 2 to the final butadiene finishing column 1~ The butadiene stream is at a tQmperature of about 115F3 which temper-ature may be varied from about 110 to about 120F, and contains about 85 weight per cen~ of butadiene, the balance being a mixture o~ cis- and trans-butene-2 (approximately 14 weight per cent), butadiene-1,2 ~abou~ 1 weight per cent) and acetylenes ~nearly 1 weight per cent). The butadiene content o~ the stream in line 2 may vary from about 8S to about 95 weight per cent9 the cis and trans-butene-2 may vary from about 2 to about 14 lllQ9LS17 weight per cent, the butadiene-1,2 may range from almost zero to about l w~ight per cent and the acetylenes may range Erom almost zero to about 1 weight per cent. S-team at about 15 psl is Eed to the two heat exchangers 7 and 7a by lines 8 and 8A at a total rate of about 16,000 pounds per hour. The temperature o~ the material in lines 9 and '!
9A is thereby increased to about 1~8F, although lt may be varied Erom about 125 to about 130F. A liquld bottom stream is removed from column 1 through line 5 at a rate o~ about 4,000 pounds per hour and comprises buta-diene-1,3, cls- and trans-butene-2, some butadiene-:L,2 and some acetylenes. The overhead ~rom the column is removed through line 3 at a rate o~ about 130,000 pounds per `~
hour. This stream of purified butadiene contains at least 97, and preferably at least 98.5 weight per cent of: buta-diene-1,3, up to about 2, and preEerably 1, weight per cent of butene-2, and traces of butadiene-1,2 and acetyl-enes. After condensation to the liquid state (not shown), approximately 14,000 pounds per hour of this stream is removed as pure liquid butadiene and approxLmately 116,000 pounds per hour is recycled through line 4 back to the column for purposes of reflux con~rol.
Also in a process of the prior art and with reference to Flgure I, a polar solvent stream is fed through line 26 to distillation tower 25. This stream contains about 10 weigh~ per cent~of acetonitrile and about 90 welght per cent o water, although the composi-tion may range from about 5 to about 12 weight per cen~ of acetonitrileg the balance being water~ The temperature of the stream ln line 26 is about 160F, although thls can ~ 7 " .
. .: ' be varied from about 152 to abou~ 164F. Steam is fed into the tower through line 27 (lS0 psl s~eam, at a low rate oE about 10,000 pounds per hour). The Elow from the bottom o:E the tower through line 28 i6 7 / ,,, ~ '~
'::
: / ~
: /
: ~ / '~, :'' /
'~~
- 7~ -about 40~000 poun~s p~r llottr. The overhead vapour s~re~rn is rer~.oved ~roug~ ].lne 23~ This overhead stream contai.ns about 70 ~7eig~t per cent of acetonitr:i.le a.nd about 30 ~elght per cent o~ water, altliough the cornpo.~3itlon may be varied from about 60 to abou~ ~0 weight per cent acetonltrile and rom a'bout 20 to about 40 weig~t per cent of water The ' :' temperature of the vapor stream ln this Example is about 185F, although this te~perature ma~ ~e varied ~rom about 180 to '~' about 1~0F~ e rate o:E flow in line 23 is about 14,00Q
pounds per hourJ althowgh the flow rate may 'be varied Erom about 11,000 to abou~ 17,000 po~mds per hour~ Val~s 14 and 16 are closed and valve'17 is open so that the vapor stream ~.
is passed directly to tEIe Eleat exchanger lS ~or cooling, the cooled liqu~d product in l.ine 20 ~eing at a ternperature of about 120F, although this temperature may be varied from abo~t llSC to about l30F~ From line 20,~about 5,uoo pouNds ;~
per hour of liquid acetonitrile-water c~re removed through ~ ~
line 21 for supply to t~e extractive dist~lllation process ' .
and about 9,000 pounds per hour are returned through line 22 to t~e tower, ~or purposes of re:Elux control~
When operating the process according to the present '~
invention and with reference to Figure 1, the hot vapor in line 23 is passed to the heat exchanger 11 to supply heat for the operation of column 1. This is achieve(l by cIosing valve 17 and opening ~alves 14 and 16~ tnereby causing the vapqr :
in line 23 to pass by line 13 to Pxchanger 11 an~ bac~ t'nrough line 15 to exc~anger I8 for any fur-ther cooling necessary ~: before the. liquld stream joîns the remainder o the process~
~t a flo~ ra'.e OI a'bout 1`~-~,000 pound5 per hour of vapor at a temperature or a~out 1~5~J condensation of the vapor in 4~
eXCILanSgt?r l:l to ~ uld a~ a l:emyeratwre of abo-wt 170F is equival~nt t:o supplyitl~ a~out 8,000 poun~s pe~ hour oE steam. l'hus, of the approximately 16,000 pounds per hour o~ 15 psl steam necessary ~o heat the c:ontents of col-umn l, about 8,000 pounds per ~our can be repl.acecl by the condensation of the polar solvent vapor ~o liql.lid ln exchange ll~
Remaining heat necessary for the operation of tor7er 1 can be supplied by steam suppl:iecl to either or both of exchangers :
7 alld 7A, as in t~le prior art~ .
Thus-, by the process accordinS~ to the present invention, at least 50~ of t~e ~ea-t energy requirements for the operation of colu~n 1 are obtained by cond~nsation oE a hot vapor stream rom the operation of tower 25~ This energy saving corresponds to between 5 and 10'70 of the total steam consumption of tlLe-butadiene recovery and puri~ication :Eacili ~Yy.
: .
' '~ '.
'' `
.~ ~
~0
l'h~ in~e-rltic)il is cL-irected ~o a IlleelrLs o:E corlserv;.rlg energ~, especiall.y helt erler~,y, in a butadiene re~covery ancl puri fica.Lion -E!rocess ~ .
[t :is well kno~.n in the prior art that butadiene is ol~tainable by crackirlg of hi.~her molecul.lr weight hydrocarbolls or by dehydrogenatiorL of n-~uk~me or n-butenes and that the butadiene so produced is mixed with other hydrocarbons, typically i.ncludîng other CL~ hydrocarbons~ The mixture con-ta~nirg butadiene is not a~enable to slmple distilLation processes for the recovery of pure butadiene there~rom because of the simIlar vapor pressures of many of the compo-nents i`n the mixture. Thus, it has proved necessary to obtain pure butadîene by methods ot~er t'rLan simple d:istillation~ O~e met~Lod that has achieved consiclerable commercia:L acceptance is the use of an exkractive dlstiLlat:ion of the mixture in the presence of particular polar solvents, which polar solvents alter the volatility of certain co~ponents of the mixture such that a dîstillation process may be used~ Suitable polar solvenks include acetonItrile, dimethyl formamlde~ N-methyl .0 pyrrolidine, furfural, dimethyl acetamide, sulpholane and others~
By the selection OL suitable polar solve.nts fo~ an extractive distIllatlon, t~e miY~ture of butadiene and other C~ hydrocarbons ma~ be distilled to yield a butadiene rich stream because the presence o~ the polar solvent causæs th~
butanes a~l butenes present in the mixture to exhibit a higher volatillty permltting t~ei.r separatiorl by distillation from ~
the les,s volatile butadiene and acetylenes~ By silch an ex- ~ -tractî~Te d-istillation process~ the butanes and butenes are 3~ relnoved as an ovexLlead stream and th2 butadiene and ace~-~lenes .~ ~
are re~llovcd, toge~.iicr wit:h t:l~e polar ~Sol-ve~nt, a~ a ~otlo~ns Stl eal~ Thls l~ot~oms stream is ~.hen su~jecte~l to a stri.I)ping ::
~ste~ Jher~by the polar sol~ent is separat.ecL ~rorn the buta-diene y:ielcl:ing a vapor rich in butadielle and corltaining some ace~ylenes as :impurities~ Tllis vapor rlch in bu~adle~e i5 then condensed and fed to a fillaL butadielle fi.nishing column wl~ere it i.s dist~lled and butadien having a purity o~ at least 97 ~Teight per cent is obtained as an overhead -vapor~ ::
stream. T~is final butadiene finishing column requires a supply of heat for I~s operation~
The polar s-olvent separated ~rom the.butadiene and ~,. ~ . .
acetylenes in the stripp~ng step is subjected to purifica~
tion for re use in tl~e extractive dîstillation process~ This ~ ~ -puriEication may comprise a number of steps including removal of residual hydroc~rbons contained therein, washing with e.g~ :
~Jater and ~nally a distillation~ The distilLation of the polar solvent yields a product suitable ~or rec~cling to the : extractive d~stillation stage of th.e process~
For operation of~the final hutadiene finishing ~ -column, heat is suppl-ied ~y one or more rebollers attached :
~o the bottom of the column~ For t~e polar solvent distil- .;
lation, the majorit~ of the heat is supplied by dire~t addition of stea~ to the distillation col~mn~ -Because o~ the ne~d to be able to separate all t~e compon~nts~ as descri~ed above~ and to ~e able to conde~se, ~ :
where necessary, various ~ydrocarbon streams usin~ ambient - ~-temperature process w~ter rather than special relrigeration ~ -~
units, the temperatures and pressures witllin the whole : ~ process have to be carefully ~aianced - .if the pressure in a hydrocàrbon str~am is too low it ~ou:ld T~ di:Efi;cult to readily COnden~Se j ~. 'L~Lf~ ~7hO1e process :is fa:irly energ~ enSiV``
ancl~;litll tocZay's en.ergy costs any reclllctioIl o:E energy used in ~he process is highl,~ desira~le~
l~e have no~l discovered a met:hod o~ c.onserviny, heat:
energy in a butadiene reco~Jery .~nd pur.if:ication proc.ess wherein ~he heat obtained by tlle condensation of a hot vapor stream to a lîquid stream is used.to at least partly s~pply the heat necessary toopera-te a butadiene ~lnishincr column.
It is an O~JectiVe of this invention to provide an lmproved process Eor the recovery of butadiene Erom mixtures thereof with ot'~er C4 hyclrocarbons~ ~here-ln, a~ter separation o:E the butadiene from the other C~ hydrocarbons hy extractive distillation in the presenc:e o~ a polar solvent and subsequen-t separation oE the polar solvent to yield a b-utacl.lene enric'hed stream, the buta~iene enriched strea~ is Eed to a final ~u,a-diene finlshing column operated t.o ca,use the distilla~ior therein and separdtion of a stream containing:at least 97~10 butadiene-1,3, the improvement being the s~ply of at le~ast a portion o the heat necessary for the operation o.L said .-final butadiene finishing column by heat exchange of ~he contents o said finishing col~unn with a ~ot vapo: stream comprislng said polar solvent, said hea~ being essentially that obtained by the condensation o~ said hot ~rapor stream ,~ ' to a liquid stream. , l~herever used herein) ~utadiene means bu~adieI~e~
Reference is made to Figure 1 whlch rerc~res-ents a schemc-L-~ic flow diagram :Eor a process of th~ pri.or art and of the present invention.
In Figure 1, 1 is a Einal 'butadiene finls~lng column7 the impure butadi~ne being fed to it through l:i.rLe 2 ~ 5 ~ 7 T'ue pur:ified b.Lta~ .ne v~por is removed via l:Lne 3 ancl condensed (not sho~n~. Part of ~he liqui:Eied buta~iene is removed as hlgh purity b~l~adierle and th~ remainder i.s re:Eluxecl b~cl; by lln2 4 :into column l. The heat: to operate the finisllincr colulrlll l ;.s suppl-ied by circulating.the llcluld from the bottom of the column through two heat exchangers~ In the prior art, the llquld was fed ~y lî.nes 6 and 6A through . :~-:
heat e~changers 7 and 7A, being suppliecl with.steam throug'n : .
lines, 8 and 8A, and the heated liquid was returned to t~e lQ column by lines 9 and 9A~ : :
The distillation to~Jer 25 is used to purify the polar solvent used elsewhere in the process ~or the extractive . ~ ;
distilLation of butadiene (not sho~n~ The impur~ polar ~.
so~ent stream is fed to tower 25 by line 26. Steam îs ::~
supplied to the tower through lin.e 27. The liquid bottoms of the tower are removed through lîne 28 and a.re recycléd~`to other parts of the process~ The overhead vapor stream îs removed ~rom the tower through line 23 As în the prior art, ~ .
when valves l4 and 16 are closed and valve 17 is open~ the.
: 20 vapor is passed through the heat exchanger 1~ and cooIed by :
ambient temperature water :Eed through lîne 19~ l'he liquîd stream pa3ses from the exchanger 18 by line 20 and is then ~ed partly through line 22 ~ac~ înta the distillatîon tower 25 ~or reflux control purposes and partly through line 21 to the process for the extractîve distilla~ion of bukadiene ~not shown)~
In ~he process of the present invention, heat îs supplied to column 1 b~ cîrculatîng the llquid through lî`ne lO
to neat exchanger 11 and ~ack -to the cslumn ~ line 12~ :
Ad~itioIIal heat, as required, can be suppLiecL b~ one or b~th - 5 - :
o~ heat exchangers 7 and 7A being operated with elther no steam to one of 7 or 7A or reduced steam :flow to one of or bo~h o:E 7 or 7A. The heat to exchanger 11 is supplled by closing valve 17 and opening values 14 and 16 so that the hot polar solvent vapor passes through line 13 to heat e~changer 11 and back through line 15 as a hot liquid.
~epending on the conditions required in the process, the ho~ liquid stream in line 15 may or may not be further cooled in heat exchanger 18, cooling being controlled by whether or not ambient temperature water is fed through exchanger 18.
Thus, the present invention can be clearly seen as utilizing the heat available from the condensat-Lon o~
the hot polar solvent vapor to the liquid state. Heat available from urther cooling of the liquid polar solvent is very small compared to that for the change o:E state from vapor to liquid.
In an example of the process of the prior art, and with reference to Figure 1, approximately 18,000 pounds per hour of impure butadiene is fed by line 2 to the final butadiene finishing column 1~ The butadiene stream is at a tQmperature of about 115F3 which temper-ature may be varied from about 110 to about 120F, and contains about 85 weight per cen~ of butadiene, the balance being a mixture o~ cis- and trans-butene-2 (approximately 14 weight per cent), butadiene-1,2 ~abou~ 1 weight per cent) and acetylenes ~nearly 1 weight per cent). The butadiene content o~ the stream in line 2 may vary from about 8S to about 95 weight per cent9 the cis and trans-butene-2 may vary from about 2 to about 14 lllQ9LS17 weight per cent, the butadiene-1,2 may range from almost zero to about l w~ight per cent and the acetylenes may range Erom almost zero to about 1 weight per cent. S-team at about 15 psl is Eed to the two heat exchangers 7 and 7a by lines 8 and 8A at a total rate of about 16,000 pounds per hour. The temperature o~ the material in lines 9 and '!
9A is thereby increased to about 1~8F, although lt may be varied Erom about 125 to about 130F. A liquld bottom stream is removed from column 1 through line 5 at a rate o~ about 4,000 pounds per hour and comprises buta-diene-1,3, cls- and trans-butene-2, some butadiene-:L,2 and some acetylenes. The overhead ~rom the column is removed through line 3 at a rate o~ about 130,000 pounds per `~
hour. This stream of purified butadiene contains at least 97, and preferably at least 98.5 weight per cent of: buta-diene-1,3, up to about 2, and preEerably 1, weight per cent of butene-2, and traces of butadiene-1,2 and acetyl-enes. After condensation to the liquid state (not shown), approximately 14,000 pounds per hour of this stream is removed as pure liquid butadiene and approxLmately 116,000 pounds per hour is recycled through line 4 back to the column for purposes of reflux con~rol.
Also in a process of the prior art and with reference to Flgure I, a polar solvent stream is fed through line 26 to distillation tower 25. This stream contains about 10 weigh~ per cent~of acetonitrile and about 90 welght per cent o water, although the composi-tion may range from about 5 to about 12 weight per cen~ of acetonitrileg the balance being water~ The temperature of the stream ln line 26 is about 160F, although thls can ~ 7 " .
. .: ' be varied from about 152 to abou~ 164F. Steam is fed into the tower through line 27 (lS0 psl s~eam, at a low rate oE about 10,000 pounds per hour). The Elow from the bottom o:E the tower through line 28 i6 7 / ,,, ~ '~
'::
: / ~
: /
: ~ / '~, :'' /
'~~
- 7~ -about 40~000 poun~s p~r llottr. The overhead vapour s~re~rn is rer~.oved ~roug~ ].lne 23~ This overhead stream contai.ns about 70 ~7eig~t per cent of acetonitr:i.le a.nd about 30 ~elght per cent o~ water, altliough the cornpo.~3itlon may be varied from about 60 to abou~ ~0 weight per cent acetonltrile and rom a'bout 20 to about 40 weig~t per cent of water The ' :' temperature of the vapor stream ln this Example is about 185F, although this te~perature ma~ ~e varied ~rom about 180 to '~' about 1~0F~ e rate o:E flow in line 23 is about 14,00Q
pounds per hourJ althowgh the flow rate may 'be varied Erom about 11,000 to abou~ 17,000 po~mds per hour~ Val~s 14 and 16 are closed and valve'17 is open so that the vapor stream ~.
is passed directly to tEIe Eleat exchanger lS ~or cooling, the cooled liqu~d product in l.ine 20 ~eing at a ternperature of about 120F, although this temperature may be varied from abo~t llSC to about l30F~ From line 20,~about 5,uoo pouNds ;~
per hour of liquid acetonitrile-water c~re removed through ~ ~
line 21 for supply to t~e extractive dist~lllation process ' .
and about 9,000 pounds per hour are returned through line 22 to t~e tower, ~or purposes of re:Elux control~
When operating the process according to the present '~
invention and with reference to Figure 1, the hot vapor in line 23 is passed to the heat exchanger 11 to supply heat for the operation of column 1. This is achieve(l by cIosing valve 17 and opening ~alves 14 and 16~ tnereby causing the vapqr :
in line 23 to pass by line 13 to Pxchanger 11 an~ bac~ t'nrough line 15 to exc~anger I8 for any fur-ther cooling necessary ~: before the. liquld stream joîns the remainder o the process~
~t a flo~ ra'.e OI a'bout 1`~-~,000 pound5 per hour of vapor at a temperature or a~out 1~5~J condensation of the vapor in 4~
eXCILanSgt?r l:l to ~ uld a~ a l:emyeratwre of abo-wt 170F is equival~nt t:o supplyitl~ a~out 8,000 poun~s pe~ hour oE steam. l'hus, of the approximately 16,000 pounds per hour o~ 15 psl steam necessary ~o heat the c:ontents of col-umn l, about 8,000 pounds per ~our can be repl.acecl by the condensation of the polar solvent vapor ~o liql.lid ln exchange ll~
Remaining heat necessary for the operation of tor7er 1 can be supplied by steam suppl:iecl to either or both of exchangers :
7 alld 7A, as in t~le prior art~ .
Thus-, by the process accordinS~ to the present invention, at least 50~ of t~e ~ea-t energy requirements for the operation of colu~n 1 are obtained by cond~nsation oE a hot vapor stream rom the operation of tower 25~ This energy saving corresponds to between 5 and 10'70 of the total steam consumption of tlLe-butadiene recovery and puri~ication :Eacili ~Yy.
: .
' '~ '.
'' `
.~ ~
~0
Claims (6)
1. An improved process for the recovery of butadiene from mixtures thereof with other C4 hydrocarbons, wherein, after separation of the butadiene from the other C4 hydro-carbons by extractive distillation in the presence of a polar solvent and subsequent separation of the polar solvent to yield a butadiene enriched stream, the butadiene enriched stream is fed to a final butadiene finishing column operated to cause the distillation therein and separation of a stream containing at least 97% butadiene-1,3, the improvement being the supply of at least a portion of the heat necessary for the operation of said final butadiene finishing column by heat exchange of the contents of said finishing column with a hot vapor stream comprising said polar solvent, said heat being essentially that obtained by the condensation of said hot vapor stream to a liquid stream.
2. The process of Claim 1 wherein the hot vapor stream comprising said polar solvent is at a temperature of about 180° to about 190°F.
3. The process of Claim 2 wherein the temperature for the operation of the final butadiene finishing column is from about 125° to about 130°F.
4. The process of Claims 1, 2 or 3 wherein the butadiene enriched stream contains from about 85 to about 95 weight per cent of butadiene.
5. The process of Claims 1, 2 or 3 wherein at least 50%
of the heat necessary for the operation of said final buta-diene finishing column is supplied by the condensation of said hot vapor stream to a liquid stream.
of the heat necessary for the operation of said final buta-diene finishing column is supplied by the condensation of said hot vapor stream to a liquid stream.
6. The process of Claims 1, 2 or 3 wherein said hot vapor stream contains from about 60 to about 80 weight per cent of acetonitrile and from about 40 to about 20 weight per cent of water.
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA283,881A CA1104517A (en) | 1977-08-02 | 1977-08-02 | Energy conservation in a butadiene process |
| GB2244278A GB1564680A (en) | 1977-08-02 | 1978-05-25 | Energy conversation in a butadiene recovery process |
| TR2016178A TR20161A (en) | 1977-08-02 | 1978-05-30 | ENERGY ENCLOSURE FROM A BUTADIEN PROCEDURE |
| FR7816236A FR2399397A1 (en) | 1977-08-02 | 1978-05-31 | PROCESS FOR SEPARATING BUTADIENE FROM HYDROCARBON MIXTURES |
| DE19782823901 DE2823901A1 (en) | 1977-08-02 | 1978-05-31 | PROCESS FOR THE SEPARATION OF BUTADIENE FROM MIXTURES OF THIS WITH OTHER C LOW 4 HYDROCARBONS |
| JP6560678A JPS5427503A (en) | 1977-08-02 | 1978-05-31 | Method of recovering butadiene |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA283,881A CA1104517A (en) | 1977-08-02 | 1977-08-02 | Energy conservation in a butadiene process |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1104517A true CA1104517A (en) | 1981-07-07 |
Family
ID=4109253
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA283,881A Expired CA1104517A (en) | 1977-08-02 | 1977-08-02 | Energy conservation in a butadiene process |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS5427503A (en) |
| CA (1) | CA1104517A (en) |
| DE (1) | DE2823901A1 (en) |
| FR (1) | FR2399397A1 (en) |
| GB (1) | GB1564680A (en) |
| TR (1) | TR20161A (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3032780A1 (en) * | 1980-08-30 | 1982-04-15 | Krupp-Koppers Gmbh, 4300 Essen | METHOD FOR PROCESSING THE SWAMP PRODUCT OF EXTRACTIVE DISTILLATION PROCESSES FOR THE PURIFICATION OF PURE HYDROCARBONS |
| JPS5879932A (en) * | 1981-11-06 | 1983-05-13 | Japan Synthetic Rubber Co Ltd | Purification of butadiene or isoprene |
| US4690733A (en) * | 1985-03-20 | 1987-09-01 | Union Carbide Corporation | Process for the separation of hydrocarbons from a mixed feedstock |
| US4587370A (en) * | 1985-06-05 | 1986-05-06 | Uop Inc. | Aromatic hydrocarbon alkylation process product recovery method |
| KR101440637B1 (en) | 2006-07-12 | 2014-09-19 | 바스프 에스이 | Method for separating a c4 fraction by means of extractive distillation using a selective solvent |
| KR101727362B1 (en) * | 2014-05-22 | 2017-04-14 | 주식회사 엘지화학 | Apparatus and method for purifying cumene |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE781027A (en) * | 1971-03-29 | 1972-09-22 | Shell Int Research | |
| US4038156A (en) * | 1976-09-21 | 1977-07-26 | Shell Oil Company | Butadiene recovery process |
-
1977
- 1977-08-02 CA CA283,881A patent/CA1104517A/en not_active Expired
-
1978
- 1978-05-25 GB GB2244278A patent/GB1564680A/en not_active Expired
- 1978-05-30 TR TR2016178A patent/TR20161A/en unknown
- 1978-05-31 FR FR7816236A patent/FR2399397A1/en active Granted
- 1978-05-31 DE DE19782823901 patent/DE2823901A1/en not_active Withdrawn
- 1978-05-31 JP JP6560678A patent/JPS5427503A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5427503A (en) | 1979-03-01 |
| GB1564680A (en) | 1980-04-10 |
| TR20161A (en) | 1980-09-29 |
| DE2823901A1 (en) | 1979-02-15 |
| FR2399397B1 (en) | 1984-06-22 |
| FR2399397A1 (en) | 1979-03-02 |
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