Патент USA US2411256код для вставки
Nov. 19, 1946. F, E, FREY 2,411,256 CONVERSION 0F HYDRocARBoNs Film> Novl 13, 1942 __/È RKI BY gw?" ATToRNEx/s Patented Nov. 19,r ‘1946 y 2,411,256 ?UNITED STATES PATENT oFFlc @2,411,256 ~ ~ »CONVERSION 0F HYDROCARBON S Frederick E. Frey, Bartlesville, Okla., assignor to Phillips Petroleum Com pany, a corporation of Delaware Application November 13, 1942, SerialNo. 465,495 2 Claims. 1 (Cl. 260-680) . 2 Thisinvention relates to the production 'lof di ' olefin hydrocarbons -from more saturated hydro be carried out in the presence or absence of cat alysts.` tion of low-boiling `diole?ins,particularly butadi- ' ` `Acetylene can be ~produced by pyrolysis of rela one and pentadienes from paralfln and oleñn hy tively more saturated hydrocarbons at partou larly high temperatures with a yield of. 5 to l0 Weight per cent and higher of the total products. At the time and temperature levels suited for ,effecting juncture with ethylene to produce bu _dijocarbons.I Butadiene and related dioleñn hydrocarbons They have been produced in a - number of Ways, including vapor-phase cracking of oils, Dyrolysis of organic compounds, dehydra tion of lower aliphatic alcohols and of butylene glycol, elimination of hydrogen halide from di halides of paraffin hydrocarbons, dehydrogena- , ` tadiene, there is a strong tendency for acetylene to undergo auto-polymerization. This reaction takes place much more rapidly than the auto' polymerization of ethylene at the ‘same time tion` of olefin hydrocarbons, vand other :more or temperature-partialpressure conditions. Bysup „less involved chemical .processes such as the syn- ' thesis of butadiene from phenol and the co~reac~ tion ofA .acetylene and ethylene to `form butadi ene. .The last-mentioned procedure has not found wide commercialA application because the yields of desired product, were made relatively low plying, in accordance with my invention,.addi`tional acetylene .to the, reaction Zone as` it is con co ferred to total ethylene plus acetylene supplied amounts of other products stable under the ,pre ‘i t ' , for the reaction step. A concentration of buta diene results which is, substantially in excess of that obtained by exposureof a stream of react . . I'have now` found that I can successfully pro. duce substantial yields of low-boiling dioleñns, ants to one or to two consecutive pyrolytic con such as butadiene and pentadienes, from relatively version steps, in` which all reactants, in admix ture, enter and. pass through a conversion ’zone more saturated hydrocarbons of two to four .car bon atoms per molecule by a process which in-V or zones. volves cracking or pyrolyzing the more saturated f hydrocarbons and effecting combination `of por tions of the cracked products in a co-reaction step.V The more saturated hydrocarbons are those which are less unsaturated than the diole fins; i. e.) the parafûns, ethane, propane, n. bu acetylene, treating the resulting` mixture to ob >tain a fraction which comprises ethylene and acetylene in a suitable ratio, subjecting `said \ ' ` . A _` My invention further comprises variousfpre ferred methods for obtaining the desired `-ratio of hydrocarbons of the oleiin series to hydrocarbons of the acetylene series, and effecting reaction to obtain substantial production of the desired prod uct. tane, isobutane, and the `oleiins, ethylene, pro.-V pylene, the butylenes, etc. In one specific em bodiment, my invention comprises cracking a charge stock composed predominantly of' satu rated hydrocarbons of two to four carbon'atoms per molecule under conditions adapted to eiïect production of optimum yields of ethylene and sumed, a totaladdition of :many times the de sired steady` state .concentration may be made with resultant increase in the percentage o_f ‘bu tadiene toÍ6 to 10 per cent by Weight or more, re by concomitant reactions that vformed excessive vailing operating conditions.. . . ing reaction, as well as the crackingsteps, may carbons -of two to four carbon atoms perwmole Qule. `It is especially applicable to` the produc arewell known. ‘ ther the yield of butadiene. The dioleiin-formà ' An object of this invention is to provide an im proved process for the manufacture` of dioleñns. Another object of this invention is to provide an improvedrprocess for the manufacture ci dioleñn khydrocarbons from paranin and oleñn hydrocar bons having a lesser number of carbon `atoms per molecule. AnotherI object of ~ this invention is to provide such a process which involves a com bination of cracking and co-reactionsteps. . Still _ another object of this invention is to provide an fraction to reaction in a turbulence chamber or improved process for the manufacture. of buta diene from ethylene and acetylene. - Still another object is` to provide an improved processV for the multi-point reactor under conditions favorable for' the production of butadiene, and separating and recovering the desired butadiene so produced. ‘ » , manufacture of pentadiene from propylene and Oi the butadiene-depleted material, a‘fraction` comprising unreacted ethylene and/or acetylene may be advantageously recycledY to the reaction 50 improved process for-the production of dioleñns Another object is to providesuch a process in ,which the _per-pass , from an oleiin and acetylene. zone. to increase the yield of butadiene,_ and Va fraction comprising relativelyheavy Icy-products may be advantageously .cracked to increase fur acetylene. Stillanother object is to provide an 55 conversionof the oleñn. andA acetylene to dioleiins is higher than heretofore possible. 2,411,256 sired fractions. Hydrogen and methane are drawing. withdrawn through pipe I6 and valve Il, and any heavy oils and/or tar-like products are removed from the system through pipe i8 and Valve I9. I have found that low-boiling diolefin hydro carbons, such as butadiene and pentadienes, may be produced in high yields from more saturated carbons of the ethylene series and of the acet . Lf' 4 and valve I4 to fractionating means l5, which may be any system of conventional fractional distillation units suitable for separating the de » Other objects and advantages of the invention will be apparent to those skilled in the art from the following description and the accompanying hydrocarbons _of two to -four carbon atoms per molecule-by reacting gaseous unsaturated hydro » 'ÍÍ . The remaining pyrolysis products, comprising the ethylene and the, acetylene, are passed 10 through pipe 2|, controlled by valve 22, to heater 24, wherein they are heated to the temperature ylene series under selected reaction conditions that minimize side reactions. More specifically, substantial yields of butadiene (or pentadiene) of incipient reaction or just slightly below a re action-sustaining temperature. Then they are - passed through pipe 25 to reaction z_one 26, in are obtained by reacting a mixture comprising coreaction to form butadiene is effected. ethylene and acetylene (or propylene and acet 15 which I have found that, for optimum yields o‘f ylene) in a molal ratio of from about 10:1 to 50:1 at a suitable reaction temperature‘in a tur bulence chamber of the type described in my co butadiene, the'ratio of ethylene to acetylene in the reacting gaseous mixture should be in the range of about 10:1 to 50:1 by volume. If the nature and composition of the material charged pending application, Serial No. 373,047, ñled Jan uary 3, 1941, now U. S. Patent 2,330,118, issued 20 to the pyrolysis zone or the conditions of the September 21, 1943. The mixture is introduced reaction* are such that the desired lratio ofV ata high linear velocity in a direction and man ethylene ~to acetylene is not directlyj obtained; ner'such that a vigorous turbulent circulation of additional‘quantities of the component which the reaction mixture within the chamber ,is es is deficient may be added. For example, eth tablished and maintained, whereby rapid mixing 25 ylene or ethylene-rich gases Vmay be ‘added and dilution of the incoming hydrocarbons with through pipe 2l, controlled 'by valve 28,l to pipe the` already present circulating and reacting con.í 2|. Similarly, acetylene, or acetylene-rich tents of the chamber is effected. By effecting gases, `may be introduced through pipe ‘30, con such rapid mixing anddilution of the incoming trolled by valve 3|', to- pipe 25; or therf'acet hydrocarbons, the co-reaction of ethylene and ylene may be added directly to the reaction zone acetylene to formbutadiene 1s favored, and the through Valve 32 and pipe 33, provided' that it is suiiiciently> rapidly> mixed and diluted with formation of ’ polymers of ethylene and/or of acetylene isminimized. Reaction temperatures the reacting contentstherein. » . may be in the range of 550 to 900° C. at pressures ‘ Reactionl'zone 26 is preferably a turbulence of 0.2 to 2 atmospheres, or in the'range of` 300 35 chamber of the type described in my> above# to 550"> C; at higher pressures, up to about 20 at identified patent,.2,330,118. iBriefiy, itïcomprises -va chamber of relatively large cross section, rela tive to the hydrocarbon stream, into which the bons of the ethylene series and of the acetylene reaction mixture'V is introduced ata high linear series usedv for the formation of. low-.boiling di 40 >velocity and in .aY direction and manner. such olefins maybe obtained from any sourceV or pro thatV a circulation ofthe contents of ,the chamf mospheres. ‘ “ ‘ ‘ Although the gaseous unsaturated hydrocar duced by any of variousA methods known to the art, I preferY to crack hydrocarbons of >two to four Vcarbon atoms . per molecule, or mixtures thereof, which are more ‘saturated than the dioleñn hy ber is establishedand maintained; thereby.l ef fecting a rapid> mixing and dilution of'thein ll5 drocarbonsgat temperatures in the range of 850 to 1500°` C.A and at pressures of 0.2 to 3 atmos culating and reacting contents of the `chamber through constant and turbulent circulation, »which advantageously is` augmented through multipoint-wise',l addition» of the incoming` hy drocarbons, minimizes formation of‘polymers‘of ethylene and/or of acetylenaand it simultane ously favors interactionY ofY ethylene and -acet pheres for periods of time suiiicient to‘yield eth ylene and acetylene hydrocarbons in amountsfof about 15 and 5 per centby weightrof the charge, respectively. .' Y p ‘ My vinvention will now be more specifically described in connection with the `accompanying drawing, which is a diagrammatical flow diagram ' showing one mode of procedure for practicing my invention. ` , Y _ dioleñn hydrocarbons and of two to four carbon the art for effectingV and maintaining pyrolysis 60 higher pressuraup to about 20 atmospheres, are employed, _the temperatures maybe reduced to the range of 300 to 550° C. The average time of residence-of the hydrocarbons in reaction iZone 26 is preferably chosen sol as to -produce the optimum vyield of butadiene. The reaction mix 65 ture is withdrawn substantially continuously, or intermittently at suitable time intervals'` if pre ferred, from reactionl Zone or chamber `26 through or cracking` of low-boiling hydrocarbons. (The hydrocarbon charge Vmay be augmented'by re cycled material from pipe 44, controlled by valve 45.) The pyrolysis Vis prefer'ably‘effectedat 350 to 1500° C. andfat 0.2'Ytof3V-atmospheres,.depend ing upon theyco'mp’ositiorif 'of theèchargefsto'ck‘; the reaction time is such asïto convert about 1' to pipe 35,l whoseV opening «is preferably» located at` a central point in zone 2S so that short-cir-` >cuiting of the reacting stream or Streamslis avoided. It is passed to separating means V35, wherein-separation into desired fractionsis ef-> fected byffractionation, absorption, extractionor 5 per cent of the chargeby weight-to acetylene . other suitable means known to the art. VOneof and about ,15 per cent or more to ethylene; `The resulting product's‘lare passed 'through"pipe‘V I3 . at temperatureszwithin> the range of 550 to 900° C. and at. pressures of 0.2 to 2 atmospheres.V >If l zone l2. Pyrolysis zone l2 is heated by suitable Yheating units, or furnaces, or the like known to ylene to ,form butadiene. Reaction within zone .26 is preferably eiîected , A vhydrocarbon material more-’saturated-'than atoms per molecule, which> may be> predominantly ethane, propane, butanes, or; mixtures thereof, is introduced into'the system through pipe I0 'and isgpassed by way of -Valve Il rto pyrolysis coming hydrocarbons with the circulating andy reacting contents. The rapid‘mixingand dilu tion of the incoming hydrocarbons >with >the cir 75 these fractions comprises chieflylbutadieneand 2,411,256 is withdrawn through pipe 31 and valve 38. Methane and hydrogen may be removed through pipe 40 and valve 4|; and any oils and/or tar like by-products may be withdrawn from the sys tem through pipe 42 and valve 43. A fraction comprising chieñy unreacted nor mally gaseous hydrocarbons heavier than methane is passed from separating means 36 through pipe 44. If predominantly parailînic, 6 these conditions 17.3 per cent of the ethylene re acted to yield a cracked product stream contain ing 3.95 per cent by weight of butadiene. The butadiene yield amounted to 22.8 per cent by weight of the ethylene reacted. Example II A mixture of ethylene and acetylene containing 3.24 per cent by weight of acetylene was reacted it is reintroduced to pyrolysis zone i2 by means 10 as outlined above at 881° C. and 0.139 second. of valve 45 and pipe I0 to be subjected to further The cracked products stream contained 2.0 per cracking. If it comprises appreciable quantities cent by weight of acetylene, 77.9 per cent of eth of unreacted ethylene and/or acetylene, it may` ylene and 5.4 per cent of butadiene. The yield be passed from pipe 44 through pipe 46 and valve of butadiene was 26.9 per cent by weight of the 41 to pipe 25, so that it is mixed with the stream C2 hydrocarbons reacted. of cracking products to reaction zone 26; how Example III ever, it preferably is passed from pipe 44 through pipe 48 and valve 49 to pipe 2|, so that it is mixed A mixture of ethylene and acetylene contain with the stream of cracking products before this ing 2.50 per cent by weight of acetylene was stream is heated to a temperature of incipient 20 cracked at 871° C. and 0.229 second at 256 mm. reaction. v If desired, reaction products intermediate in carbon content and molecular weight between butadiene and heavy oils and/or tar, may be passed from separating means 36 through pipe 25 5|, controlled by 4valve 52, to cracking Zone 53. Ii desired, other hydrocarbons or diluent gases may be added through pipe 54, controlled by of Hg absolute pressure. The cracked products contained 2.86 weight per cent of acetylene, 83.50 per cent oi ethylene and 4.96 per cent of butadi ene. The yield of butadiene was 36.5 per cent by weight of the C2 hydrocarbons reacting. Example IV In a single-pass experiment made to show the valve 55. Within zone 53, cracking is effected eiîect of a large percentage of acetylene, a mix under conditions similar to those in zone I2, 30 ture of ethylene and acetylene containing 27.56 preferably at pressures of 0.1 to 2 atmospheres weight per cent of acetylene was cracked at 810° and temperatures in the range of 850-1500° C. C. and atmospheric pressure in a quartz coil. depending upon the composition of the material being cracked. The products from cracking The time of residence at reaction temperature was 1.218 seconds. The cracked products stream zone 53 are passed through pipe 56 and valve 51 35 contained 9.81 weight per cent of acetylene, 53.86 to separating means 58; however, any desired per cent of ethylene and 4.55 weight per cent of portion of the products may be passed from pipe butadiene. In addition the cracked products 56 through pipe 50, controlled by valve 60, to stream contained 24.04 weight per cent of C5 and catalytic cracking zone 6|, wherein further heavier products. cracking is effected by catalysts such as alumina 40 The invention may be practiced otherwise than or bauxite, and the eil‘luents are passed through as speci?cally described or illustrated, and many pipe 62, controlled by Valve 63, to separating modifications and variations Within the spirit and means 58. scope of it will be obvious to those skilled in the Within separating means 58, separation into art. i desired fractions is effected by any suitable I claim: means. A butadiene fraction is withdrawn 1. The process of making butadiene from eth through pipe 64 and valve 65. Methane and hy ylene and acetylene which comprises passing a drogen are removed through pipe 66 and valve mixture consisting of ethylene and acetylene in 61. Heavy oils and/or tar are withdrawn a molal ratio of from 10:1 to 50:1 through a re through pipe 68 and valve 69. Intermediate , action zone, maintaining the reaction mixture in products, other than the butadiene fraction, are said zone at a temperature of from 871 to 881° C. passed through pipe 10, by means of valve 1|, and under a pressure of from 0.2 to 2 atmos to pipe 2| to be passed with the fractionated pheres, holding the reaction mixture in said zone pyrolysis products from fractionating means l5 for a period of time within the range of from through heater 24 to reaction Zone 26. 55 about 0.14 second to about 0.23 second, Withdraw In some cases, with suitable charge stock, it ing the reaction mixture from said zone and re may be unnecessary to fractionate the pyrolysis covering the butadiene content thereof as a prod products 'before reacting them under conditions uct of the process. favorable for production of butadiene. In such 2. The process of making butadiene from eth cases, the products formed in pyrolysis zone i 2 will pass through pipe 12', controlled by valvei13, 60 ylene and acetylene which comprises passing a mixture consisting of ethylene and acetylene con to heater 14, and then through pipe 15, con taining 3.24 per cent by weight of acetylene trolled by valve 16, to pipe 25 and reaction through a reaction zone, maintaining the reac zone 26. tion mixture in said Zone at a temperature of Example I 65 881° C. and at atmospheric pressure, holding the reaction mixture in said zone for 0.139 second, Pure ethylene was cracked at atmospheric withdrawing the reaction mixture from said zone pressure by flowing it through a narrow quartz and recovering the butadiene content thereof as tube maintained at 854° C. by a salt bath. The a product of the process. flow rate was such that the residence time at 70 reaction temperature was 0.16 second. Under FREDERICK E. FREY.