Патент USA US2117457код для вставки
May 17, 1938. H. C. SCHUTT METHOD OF CONVERTING HYDROCARBONS Filed Oct. 24, 1955 v@ Sì . AMM è. àMQ mw KtQN@ ÈwmNQ m. Patented May 17, 1938 l , 2,117,457 UNITED STATES `PATENT ori-‘ICE METHOD 0F CONVERTING HYDROCARBONS Hermann Claus Schutt,- North Tarrytown, N. Y., assigner, by mcsne assignments, to The Pure Oil Company, Chicago, lll., a corporation of Ohio Application October 24, 1935, Serial No. 46,542 11 Claims. My invention relates to a process and apparatus aromatic products therefrom, separatingthe liq under suitable conditions of temperature and uid products from the lower boiling hydrocarbons, recycling the lower boiling hydrocarbons to the pressure, to convert the same into polymers, in Ui cluding aromatic and other cyclic compounds such as naphthenes, having valuable anti-detona tion 'characteristics and suitable for use as motor fuel. 1 the production of the maximum yield of desired _ for cracking and polymerizing hydrocarbons, ' It is a primary object of my invention to pro vide a process in which low-boiling hydrocarbons such as occur in petroleum reiinery gas, particu larly gases containing a considerable amount of unsaturates such as gases from liquid phase, liquid-vapor or vapor phase cracking still opera--v tions, may be converted into heavier hydrocar bons of the aromatic series, under conditions which will result in a high yield of high octane aromatic-containing liquid boiling within the range of the nature of gasoline motor fuel, and 20 minimize the formation of undesirable products such as tar and fixed gases, e. g., methane and ethane. ‘ In general, my process comprises the separa tion of the mixture to be used as charging stock, 25 as for example, a. gas containing aliphatic Cz, Ca and C4 hydrocarbon compounds preferably com prising in excess of thirty per cent unsaturates, into fractions respectively more diiiìcultly poly merizable in accordance with the increased mo 30 lecular Weight of the unsaturates in successive initial separating step and removing stabilized 5 aromatic-containing products of the nature oi motor fuel from the system. Y In accordance with my invention, I may pass the lighter compounds, as for example, the Cz hydrocarbons of the starting mixture directly to 10 the intermediate cracking step when these form a relatively small percentage of the starting mix ture, to convert the C2 saturates to unsaturates» for polymerization in the subsequent low pressure polymerization stage. On the other hand, when the percentage of lighter C2 unsaturates in the starting mixture is relatively high, it may be pref erable to pass these directly to the low pressure polymerization stage for the production of a 20 maximum yield of desired aromatic products. I have found that the operating conditions most suitable for eii'ecting polymerization of heavier unsaturates undergoing treatment, e. g., butylene, are not suitable for the polymerization of ethylene since the latter will polymerize much more rap 25 idly under the same temperature-pressure con ditions. \ Hence, I have found it desirable to sepa rate the hydrocarbons according 'to boiling point as a measure of reaction velocity and subject them to separate stages ofl polymerization and fractions, subjecting the most diñicultly poly most favorable to the velocity constant, or reac merizable fraction, as for example, that contain ing substantially C3 and C4 unsaturated com tion velocity, of each. I have also found that during the polymeriza tion of the C3 and C4 compounds, a part of the pounds, to high temperature, high pressure poly 35 merization conditions most favorable to the pro duction of the maximum yield of desired aromatic hydrocarbons which may be obtained from that particular fraction, separating the aromatic products from the unreacted low boiling hydro 40 carbons, subjecting the unreacted hydrocarbons, as for example, the saturated Cs and C4 com pounds, to high temperature, low pressure crack ` ing conditions most favorable to the maximum yield of lighten, more easily polymerizable com 45 pounds, as for example, substantially Cz unsatu saturates present are converted to lighter un more easily polymerizable compounds as a frac this light fraction to high temperature, low pres - 50 sure polymerization `conditions most favorable to 35 saturates. The complete conversion of these saturates to C2 unsaturates is best carried out, however, by a subsequent cracking of all or a part of the polymerization reaction products from which the aromatic and other higher boiling 40 products formed during the initial polymerization stage have been substantially removed. The endothermic character of the cracking reaction is such as to permit cracking of the C2, Ca and C4 compounds as a 'group at an average tempera rated hydrocarbons, separating these lighter, - ture without excessive decomposition of the heav tion from the liquid products formed, subjecting 30 ier C4 compounds to coke or tar.« I jdo not, there fore, deem it essential that the separation of the C2, Ca and C4 saturates into their respective fractions and cracking of each separately be 45 2 2,117,457 practiced though such operation would more nearly approach ideal conditions for optimum conversion of the saturates to unsaturates. ’Assuming the charging gasto have the follow ing composition, I cool the gas under pressure to substantially separate the C3-C4 compounds as a liquid from the C2 compounds and methane as . follows: Table 10 low pressure polymerization stage may be passed 10 Mol. per MOL per uoâäid cent gas 5. s 1. 7 57. 8 n. 2 1l. 7 38. 4 14. ñ 24. 2 4. 5 19. 0 .8 8. 8 20 to the low pressure, high temperature polymeri zation coil. Where the gases remaining un condensed after llquefaction of thev feed for the first polymerizing coil contain a relatively high percentage of C2 unsaturates, I prefer to charge these gases directly to the low pressure, high tem perature polymerization coil rather than to the gas cracking coil as previously described. The gaseous chargeto the heating coil of the im. 0 1. 5 _ thereinto at a pressure of from 150 lbs./sq. in. gauge to 300 lbs/sq. in.‘gauge, preferably at about 225 iba/sq. in. gauge and rapidly brought up to a temperature sufllcient to initiate the polymerization reaction a'fter which it passes to 15 a reaction coil of greater cross-sectional „area than the heating coil, controlled as to tempera ture.- The exothermic polymerization reaction is permitted to go on in the reaction coil which 100. 0 . may be maintained at a mean pressure ranging 20 'I'he liquid fraction containing the Ca--Ci com pounds is pumped directly to a heating coil where it is brought up to a temperature sufficient to initiate the exothermic polymerization reaction after'which it is passed to a high pressure, high from 15 lbs./sq. in.- gauge to 120 lbs/sq. in. gauge, preferably about 80 -lbs/sq. in. gauge, and at a mean temperature ranging from l100° F. to 1300“ F., preferably about 1200" F. Following the proper 'time interval for polymerization, the 25 reaction products may then be quenched to a temperature reaction coil, preferably of larger temperature below approximately 600° F., pref cross-sectional area than the heating coil, con trolled as to temperature, where the polymeriza 30 tion reaction is permitted to take place. - The reaction coil may be operated at a mean tempera erably about 325° F. to inhibit'further polymeriza tion. 'I'he products, following the removal of tar and fuel oil formed during the polymerization 30 reaction, is subjected preferably to steps of ab ture range of from 1050° F. to 1150“ F., prefer sorption and rectiñcation for the recovery of un- ì ably at about 1080 F. and at a mean pressure stabilized aromatic-containing liquid free of ñxed gases such as hydrogen and methane which lat range of 200 lbs/sq. in. gauge to 400 lbs/sq. in. 35 gauge, preferably at about 300 lbs/sq. in. gauge. 'I'he polymerization reaction products withdrawn from the .reaction coil may be quenched to a temperature below approximately 600° F. and preferably about 425° F.. to inhibit the polymeri zation reaction, the products after fuel oil and tarseparation being cooled and fractionated to ter are vented as residue gas. 35 These unstabilized aromatic containing prod ucts together with those recovered by compression and cooling of the reaction products from the cracking reaction are fractionated at high pres sure for the recovery of the stabilized aromatic 40 containing products of the nature of .motor fuel. recover aromatic and other liquid products aThe overhead products of the fractionating op eration will consist mainly of a mixture of Ca-Ci formed by the polymerization reaction. The low boiling compounds such as the Cs--C4 compoundsl containing from forty per cent to saturates remaining uncondensed are passed to a eighty per cent unsaturates and may be con low pressure, high temperature gas cracking coil densed under pressure and recycled for subse quent polymerization in the high pressure poly primarily for conversion of saturates 'to Cz'un ' saturates. 'I'he cracking reaction may be carried merization coil. The tar and fuel oil separated from the re out in the heating coil at a temperature range ' 50 of from 1325o F. to 1600° F., preferably about , action products of each of the polymerization and 1375° F., and at a pressure range of from 25 cracking operations contain considerable light distillate recoverable by stripping at pressures lbs/sq. in. gauge to 125 lbs./sq. in. gauge, prefer ably about '15 lbs./sq. in. gauge. The charge to ranging from 10 lbs./s`q. in. gauge. This liquid is 45 the gas cracking coil, though primarily consist ing of the gases remaining uncondensed after sep aration of the aromatic-containing products formed by the polymerization operation,'may be supplemented by the addition thereto of the un condensed C2 gases of the initial separating oper 60 ation and the gases separated during the cooling of the polymerization products for theA removal 55 of tar and fuel oil formed. p Obviously, therewill be some polymerization of the unsaturates pres ent and- formed during the`gas cracking operation. These unsaturates, as”for example, the C2 com pounds, will form desired aromatic products. 'I'he reaction products withdrawn from the heating coil may be quenched to below active cracking temperature, i. e., to a temperature ranging below 70 approximately 600 F., preferably about 250° F. The tar and fuel oil formed is then separated _from the gaseous constituents which are compressed and cooled to condense the desired aromatic prod ucts present. 'I'he gases remaining uncondensed 75 contain the Ca unsaturates and form the charge used as a quench medium supplementing that re covered by cooling and condensation of a portion 55 of the quenched reaction products at higher pres sures. y 'It is to be understood that’ the temperatures maintained in the respective reaction coils may be varied according lto the type and amount of hy 60 drocarbons introduced, the pressure under which the respective polymerization and reaction coils may be operated, and the time of exposure of the gases to the operating temperature. In case an extremely high octane number is not desired, the 65 polymerization operations may be conducted at pressures of the order of 400 lbs./sq. in. gauge to 3000 lbs/sq. in. gauge with correspondingly lowerpolymerization temperatures ranging up ward from 700° F. - The accompanying drawing which forms part of this speciñcation and is to be read in con Junction therewith, is a schematic showing of apparatus in accordance withmy invention. ’ Refinery or pressure still gas may be intro 70 2,111,457 3 -is formed. 'I'his liquid, or polymer gasoline. duced into the system through pipe I at a pres passes from the reboiler 34 through pipe 35, heat sure of from 250 to 350 lbs/sq. in. gauge, prefer ably about 300 lbs./sq. in. gauge, partially lique exchanger 3l, pipe 35, and cooler 31 into pipe 38 fied in the condenser 2 and passed into a feed having pressure control valve 39. The polymer tank 3. Assuming the gas charged to comprise - gasoline in pipe 38. is combined with other mainly Cz, C: and C4 hydrocarbons, the hydrogen polymer gasoline formed as will be hereinafter present, methane and mainly Cz hydrocarbons shown, to produce a motor fuel of high blending may be withdrawn from the tank through the pipe 4 and passed into the light gas feed pipe 5. -The overhead products of the fractionator 33 'I'he direction of gas flow in this pipe may be will consist of ca_-C4 saturated compounds which 10 selected by suitable manipulation of the pressure pass through the condenser 45, pipe 4I and into value. control valves 6, 'l and 8 as will be more fully ex plained hereinafter. ‘ 'I'he liquefleld Ca and C4 hydrocarbons in the 15 tankl I may be withdrawn therefrom through the pipe 9 and charged by the pump I0 through the pipe Ilgat a pressure of about 400 lbs/sq. in. gauge to the heating «coil I2 of the high pressure polymerization stage where the re‘actant in pass 20 y the reflux accumulator 42. i l Condensate is with drawn through the pipe 43 by means of the pump 44 and returned thereby through pipe 45 to the primary fractionator as reflux. 15 Uncondensed Cri-_C4 gases may be vented at the accumulator pressure through pipe 45 andl pres sure control valve 41 into the heating coil 48 of thel gas cracking unit. The charge to the gas ing through the coil is brought up to the desired - cracking coil may be supplemented by the C2 20 gases in pipe 5 which flow therefrom through polymerization temperature. The reactant dis charges from the heating coil I2 into the reaction pipe 43 and pressure reducing valve 50 into pipe coil I3 Where a mean temperature of about l080° 46. Valve 8 in line 5 may be partially or entirely F. and a mean pressure of about 300 lbs/sq. in. gauge may be maintained. The time allowed for passage of the reactant through the coil I3 is sufficient to effect maximum conversion of the Cs-C4 unsaturates to higher boiling aromatic products. On leaving the reaction coil, the re 30 action products are immediately contacted in the arrester I4 with a cool -light quench distillate entering the arrester through the pipe I5 and suddenly cooled to a temperature of about 425° F. to inhibit further polymerization, the quenched products passing from the arrester into a tar separator I5. 'I'he fuel oil and tar separator I5 functions to remove such heavy polymers from the reaction products as are formed during the polymeriza 40 tion reaction, the tar and fuel oil being dis charged under the existing pressure through the pipe I1 into the feed pipe I 9 by which the tar is conveyed to a subsequent stripping operation. A valve I8 in the pipe I1 controls the passage of 45 tar into the pipe I9. Bubble plates or other suit able fractionating trays (not shown) and internal reiiuxing in the separator 'ensure sharp separa tion of the tarry products and the lower boiling hydrocarbons. The uncondensed hydrocarbons 50 may be withdrawn through the pipe 20, pass through a condenser 2l and pipe 22 into the dis tillate accumulator 23. The distillate accumu-_ lator may be maintained at a pressure of from 215 lbs/sq. in. gauge to 325 lbs/sq. in. gauge, closed. ’ The reactant in the gas cracking coil may be 25 preferably subjected to a temperature of about 1375° F. at a pressure of 'about 75 lbs./sq. in. gauge so as to- form a maximum of C2 unsaturates as Well as such aromatic-containing products of the nature of motor fuel as result from the conversion 30 of C2 unsaturates during the cracking interval. The reaction products discharged from the crack ing coil are immediately quenched in arrester 5I toabout 250° F. by cool light distillate from pipe 52, the quenched products passing through pipe 53 into fuel oil and tar separator 54. ` The tar separator 54 may be »provided with suitable fractionating trays (not shown) and by _suitable reiiuxing, a separation of such heavy tar and fuel oil as was formed bythe cracking 40 reaction from‘ the lower boiling hydrocarbons, is eil'ected. The tar separated flows through pipe 55 and pressure reducing valve- 55 into feed line I8 for subsequent stripping, `as will be more fully described hereinafter. . 'I‘he overhead products of the tar separator 54 pass through pipe 51, condenser 5,8 and pipe 59 into the quench accumulator 58. Due to pres sure drop, the accumulator pressure will range from 20 lbs./sq. in. gauge to 120 lbs/sq. in. gauge, 50 preferably about 65 lbs/sq. in. gauge with the re sultant formation of but a small quantity of con-a densate. I propose to supplement this conden sate with quench distillate recovered from strip ping of the tar as will be more fully described hereinafter. Condensate is withdrawn from the preferably about 275 1bs./sq. in. gauge. Gases may be vented from the accumulator through pipe 23’ and control valve 24 .into the light gas accumulator through pipe 8| by pump 62 which feed pipe 5. 'I'he vented> gases will be largely Cz _ returns a portion through pipe 52 as quench dis~ hydrocarbons with some methane and hydrogen. tillate to arrester 5I. The remainder is fed 60 Condensate in the accumulator 23 may be with through pipe 83 as reflux to the tar separator 54. co1 drawn through the pipe 25 and pipe 25 by means Uncondensed low boiling hydrocarbons pass of the. pumps 21 and 28. The pump 21 returns a portion of its feed as quench distillate through> from the accumulator through the pipe 54 to com pipe I5 to the arrester I4 and the remainder pressor 55 by which they may be compressed to 65 through pipe 29 to the tar separator as reñux. from 150 lbs/sq. in.- gauge to 350 lbs/sq. in. 65 The pump 28 forces its condensate feed through gauge, preferably about 250 1bs./sq. in. gauge, pipe 30, heat exchanger 3i and pipe 32 to primary and then passed through pipe 88, condenser 61 and pipe 58 into distillate accumulator 59. At fractionator 33. the pressure in the accumulator 69 of from 1.50 'I‘he fractionator 33 may be operated at a pres 70 sure of from 250 lbs./sq. in». gauge to 350 lbs./sq. lbs/sq. in. gauge to 300 lbs/sq. in. gauge, pref 70 in. gauge and by means of bubble trays (not erably 225 lbs/sq. in. gauge, the uncondensed low boiling hydrocarbons will be mainly Cz com shown), refluxing and reboiling of the frac tionatory bottoms in reboiler 34, a stabilized aro pounds, primarily unsaturates formed by the matic-containing liquid of the nature of motor cracking reaction. 'I'he condensate will be aro matics of the nature of motor fuel formed due to 75 75 fuel of 85 to 90 Octane No. CFR. Motor Method 4 2,117,457 such polymerization of C2 unsaturates asj took place in the gas cracking coil 48. pipe 84 vby pump 85 and passes through pipe 8,6, heat exchanger 81,»pipe 88, preheater 89 and pipe Gaseous C2 hydrocarbons pass from the accu |00 into combined still and rectifier tower |0|. mulator 68 through the pipe 10 into heating coil The oil may enter the tower |0| at a pressure of 1| of the relatively low pressure polymerization stage. When the percentage of C2 unsaturates in the gases fed to the system through the pipe | is -sufliciently high to render immediate poly lmerization of _these gases feasible, valves 1 and 8 10 in pipe 5 are closed and valve 6 is opened so that the C2 hydrocarbons withdrawn from the feed tank 3 through the pipe 4 pass through pipe 5 and are commingled with Vgases in pipe 18 passing to from 250 lbs/sq. in. gauge to 450 lbsr/sq. in. gauge, preferably about 325 lbs/sq. in. gauge, and at a the heating coil 1|. ’ ' l The reactant may be heated in coil 1| suili temperature of from 450° F. to 650° F., preferably , about 525° F. The absorption oil is stripped with steam entering the tower through pipe |02, the steam condensate formed in the rectifying section 10 of the tower being withdrawn from collecting trays (not shown) through pipe |03. Sharp separation of the absorption oil from the ab sorbed hydrocarbons is secured by suitable frac _tionating trays (not shown) in the rectifying sec 15 ciently to initiate the polymerization reaction tion of the tower in conjunction with cool reñux and passes into reaction coil 12 where exothermic polymerization may proceed at a mean tempera entering the tower through the pipe |04. The lean absorption oil is withdrawn through pipe |05 ture of about 1200° F. and a mean pressure` of by means of pump |08 and is returned to the about 80 lbs./sq. in. gauge. The reactant after absorber 88 through pipe |01, heat exchanger 81, 20 a time interval suñicient to form the desired aro pipe |08, cooler |08 and pipe 80. matic-containing products discharges into ar rester 13 wherein it is contacted with cool light . distillate entering the arrester through pipe 14. The_reaction/products are quenched in the ar ’ The overhead products of the tower |0| pass through pipe H0, condenser ||| and pipe ||2 rester to a temperature of about 325° F. to inhibit into separator ||3 where at a pressure of from 245 lbs/sq. in. gauge to 445 lbs./sq. in. gauge, 25 preferably about 320 lbs/sq. in. gauge and a the polymerization reaction, the kquenched re action products passing through pipe 15 into tar about 80° F., a separation of some uncondensed and fuel oil separator 16. ` 1 ' ` The tar separator 16 by means of suitable fractionating trays (not shown) and cooling re flux effects a separation of heavy tarry polymers and fuel oil formed from the lower boiling hydro carbons. The tar separated discharges through pipe 11 and pressure reducing valve 18 into pipe |8 for subsequent tar stripping, as will be more fully described hereinafter. The uncondensed overhead products of the tar separator pass through pipe 18, condenser 80 and 40 pipe 8| into quench distillate accumulator 82 which may beA maintained under a pressure of from 25 lbs./sq. in. gauge to 100 iba/sq. in. gauge, preferably about 50 lbs/sq. in. gauge, and a tem perature of from 100° F to 200° F., preferably temperature of from 60° F. to 100° F., preferably C2 hydrocarbons may be effected, these being vented through pipe ||4, pressure control valve ||5, pipe ||6 and pipe 83 into the residue gas pipe 5. The separator liquid is partly reiiux and dis charges from the separator ||3 through pipe I |1, a portion passing through pipe ||8 to pump ||8 and being returned thereby through pipe |04 to 30 35 the tower |0| as reñux, the remaining net con densate passing through pipe |20, pressure re ducing valve |2| and pipe |22 into feed tank |23. The liquid aromatic-containing products formed 40 during the gas cracking operation and collected in the distillate accumulator 68, are also passed under the pressure existing therein through pipe |24 into‘pipe |22 to the feed tank |23. Any light about 125° F. In the accumulator 82, a separa-v ' Cz hydrocarbons remaining in the liquid passing to the feed tank |23 which hydrocarbons are to carbons is made. 'I'he condensate is withdrawn be removed from the liquid may be vented Afrom _ tion of condensate from the uncondensed hydro-` through pipe 83 by'pump 84 and returned there by through pipe 14 to arrester 13 as quench dis tillate and through pipe 85 to the separator 15 as reflux. Excess condensate from accumulator 82 may be passed through valve-controlled line 86' and joined with the condensate leaving distillate accumulator 88. The uncondensed hydrocarbons 55 pass from the accumulator 82 through pipe 86, ' cooler 81 and pipe 88 into -absorber 88 of an absorption unit. 'I'he gas feed may enter the absorber at a tem peraturev of from 60° F. to 100° F., preferably 60 about 80° F., and at a pressure of from 25 lbs./sq. in. gauge to 100 lbs/sq. in. gauge, preferably about 50 iba/sq. in. gauge, and passes through the absorber countercurrent to downflowing lean the accumulator through pipe |25, valve |26, pipe ||5 and pipe 83 to the low pressure section of residue gas pipe 5. . The liquid in the feed tank |23 contains the de 50 sired aromatic-containing products of the nature of motor fuel formed-in the low pressure gas cracking and polymerization stages and is with drawn through the pipe |21 by pump |28 and 55 passed through pipe |28, heat exchanger |30 and pipe |3| into secondary fractionator |32. 'I'he fractionator |32 is a conventional stabilizer which may be operated at from`2'l5 lbs./sq. in. gauge to 475'lbs._/sq. in. gauge, preferably about 60 350 lbs./sq. in. gauge, and have suitable reboiling means |33.- The bottoms discharged from the reboiler |33 are aromatic-containing products of absorption oil entering the absorber through pipe v the nature of motor fuel of 90 to 100 Octane No. 65 80. The aromatic and other normally liquid CFR Motor Method stabilized as to end point products of the nature of motor fuel together with and these, pass through pipe |34, heat exchanger 65 most of the Ca-Ci hydrocarbons which comprise from forty per cent to eighty per cent unsatu rates, are removed from the gases by the absorp 70 tion oil, the residual hydrogen, methane and some C2 hydrocarbons passing ofi' through pipe 8|, pressure reducing valve 82, and pipe 83 into -the ' residual- gas pipe 5, in which valve 8 may be partially or entirely closed. 75 ' s . The rich absorption oil is withdrawn through |30, pipe |35, cooler |36, pipe |31 and pressure reducing valve |38 into pipe 38 wherein they are blended with the stabilized aromatic products of the high -pressure polymerization operation and 70 discharged from the system as the flnaiproduct. 'I‘he overhead products of the fractionator |32 are mostly C3-C4 hydrocarbon compounds which pass` through pipe |38, condenser |40 (wherein they are substantially completely condensed) and ' 75 5 2,117,457 pipe |4| into reflux accumulator |42. A portion of the condensate is withdrawn from the accu mulator |42 through pipe |43 by pump |44 and returned through pipe |45 to the fractionator |32 as reflux. The net condensate in the ac cumulator |42 ñows through the pipe |46 under the existing pressure'back into the pipe I as re cycle entering the system with the fresh gas. The tar and fuel oil separated from the reac 10 tion products following each of the conversion steps and discharged into the feed pipe |9, passes tract the remaining heavier gas fractions and light vapors therefrom. The unabsorbed gases are eliminated through line 9|. The absorbed constituents are eventually passed through line |20 to join the distillate from the cracking stage in line |20. The combined liquid fractions are passed to accumulator |23 and from there to fractionator |32. The gas from fractionator |32, which was dissolved in and separated from the liquid fractions, is recycled through line |46 to tower |49 wherein at a reduced pressure of from the high pressure polymerization coil |2. While the foregoing description of my process illustrates the treatment of the Ca-Ci unsat 10 lbs/sq. in. gauge to 50 lbs/sq. in. gauge, pref urates in the high pressure,4 high temperature through heater |41 and pipe |48`into stripping 15 erably about 25 lbs/sq. in. gauge, and by the addition of heat, the fuel oil and tar may be stripped of the lower boiling hydrocarbons and passes from the stripping tower through the pipe |50. cooler |5I, pipe |52 and pressure reducing 20 valve |53 to storage tanks (not shown). The lower boiling hydrocarbons flow upwardly through fractionating trays (not shown) counter current to downñowing reflux. the overhead products passing through pipe |54, condenser |55 25 and pipe |56 into accumulator |51. The low boiling quench condensate formed is withdrawn from the accumulator through pipe |58 by pump |59 which discharges through the pipe |60. A portion of the distillate in the pipe |60 is re 30 turned through pipe IBI and pressure control valve |62 to the tar stripper |49 as reflux. 'I’he net `discharge from the pipe |60 passes 10 polymerization coil and the treatment of the C2 15 unsaturates formed by cracking or by separation from the gases entering the system, in a separate high temperature, low. pressure polymerization coil, it is to be understood that this is by. way of example only. My process comprehends 20 broadly the treatment of the polymerizable nor mally gaseous oleflnes lunder polymerizing con ditions of heat and pressure which are in so far as is commercially practical, establishedas most favorable to the differing reaction velocities of 25 the respective hydrocarbons undergoing treat ment. ` It will be understood that certain features and sub-combinations are of utility and may be em ployed Without reference to other features and 30 sub-combinations. This is contemplated by and is within the scope of my claims. It is further obvious that various changes may be made in de tails within the scope of my claims without de through supply pipe |63 from which streams may be returned through pipe |64 and pressure con 35 trol valve |65 to quench accumulator 60, through parting from the spirit of my invention. It is, 35 pipe |66 and pressure control valve |61 to dis therefore, to be understood that my invention is tillate accumulator 23 and through pipe |69 and not to be limited to the speciñc details shown pressure control valve |69 to quench accumulator and described. 82, respectively. , Having thus described the invention, what is ’ ' Although I have described my invention in claimed is: 40 40 1. The process for obtaining liquid aromatic connection with the conversion of gases contain hydrocarbons from normally gaseous olefin-con ing a substantial proportion of oleñnic or un saturated hydrocarbons, it will be understood taining hydrocarbons, which comprises separat that natural hydrocarbon gases or refinery gases ing said gaseous hydrocarbons into fractions of successively lower boiling range, separately heat 45 of low olefin content may also be treated sepa rately or in conjunction with gases rich in ole -ing a fraction of higher boiling range to initiate polymerization of the unsaturates present, in fins. When the treatment of low oleñn contain ing gases is contemplated, these gases may be troducing the heated fraction to a reaction zone fed into the pipe 46 leading to the cracking coil 48 in order to ñrst crack the gases. The resulting wherein formation oi' polymers occurs, removing the products of reaction from the reaction zone, products may be treated in the same manner as fractionally separating the Aproducts of reaction 50 into a tar fraction, an aromatic polymer frac tion and unpolymerized hydrocarbons of suc pointed out with respect to gases fed from pri mary fractionator 33 and line 49. When starting with predominantly saturated gas, it is cracked in the coil 48, chilled at 5|, and the tar separated from the reaction products in unpolymerized hydrocarbons so separated to a temperature at which said hydrocarbons will be 54.- ~The remaining'products pass through con- l converted into unsaturated hydrocarbons, com- ~ denser 59 and accumulator 60 where part of the bining gaseous reaction products from the last mentioned conversion step with a ñrst mentioned fraction of lower boiling range than the fraction subjected to the aforesaid polymerization stepV 60 separately heating the combined gas fractions to initiate polymerization of the unsaturates pres reaction products are condensed and recycled as cooling and reflux stock. The remaining uncon densed vapors and gases pass through line 64 and compressor 65 and condenser 61 to accumu lator 69. 'I'he heavier fractionsl of the gas, to gether with the aromatic distillates, are con 65 densed and collected in 69. The Cz compounds, which are not condensed, vare then charged through heating coil 1| and reaction coil 12 for polymerization. After separation of the tar from the polymerized reaction products, the remain ing products are cooled. The condensate is used for chilling and reñux stock and any excess is passed through line 86’ and joined with the con densate from the cracking stage in line |24. The gases from the polymerization stage are treated 75 with absorbent liquid -in tower 89 in order to ex cessively lower boiling ranges, separately heating ent, introducing the heated fractions last men- ` tioned to a separate reaction zone wherein for mation of polymers occurs, removing the prod 65 ucts of reaction from said last mentioned zone, and fractionally separating said last mentioned products of reaction into a tar fraction,~ an aro matic polymer fraction and normally gaseous hy drocarbons. » 70 - 2. The process of claim 1 including recycling only the higher boiling portions of said last men tioned normally gaseous hydrocarbons to said ilrst mentioned heating step for further poly merization. - ` . 6 2,117,457 Y 3. The process for obtainingliquid aromatic -reaction products into a heavy polymer fraction, hydrocarbons from normally gaseous hydrocar a fraction' containing the gasoline boiling range bons, which comprises separating said gaseous constituents and a. gaseous' fraction, combining hydrocarbons into liquid and gas fractions of the last mentioned gaseous fraction with one of successively lower boiling range, separately heat said ñrst mentioned fractions of lower boiling ing said liquid fraction at high pressureto ini tiate polymerization of the unsaturates present, introducing the heated fraction to a reaction zone wherein formation of polymers occurs, removing 10 the products of reaction from the reaction zone, and quenching them to inhibit the polymeri 15 zation reaction, fractionally separating the sure in a separate reaction zone suitable for quenched products into a tar fraction, an aro matic polymer fraction and unpolymerized gas, polymeriz'mg unsaturated hydrocarbonsto aro matic hydrocarbon liquids, said last mentioned separately heating said unpolymerized gas and temperature and pressure being respectively a first mentioned gas fraction at a relatively low pressure to a temperature at which said fractions higher and iowen-than those to which said gas eous hydrocarbon fraction is subjected _in the will be converted to form polymers and substan tial quantities of unsaturated hydrocarbons, re 20 moving the products of reaction from said last mentioned heating zone, and quenching them to inhibit the cracking- reaction, separating the quenched products into a tar fraction, an -aro matic polymer fraction anda gas fraction con 25 taining unsaturates, separately heating said last mentioned gas fraction together with a nrst men tioned gas fraction at a relatively low pressure to initiate polymerization of the unsaturates pres ent, introducing the heated fraction last men ' gases are recirculated to the first mentioned con version step. . 9. 'I'he process for obtaining liquid hydrocar bons from normally gaseous oleñn containing hy 25 drocarbons, which comprises separating said gas eous hydrocarbons into a fraction Jcontaining mation of polymers occurs, removing the prod portion of said fraction to liquid hydrocarbons polymerization reaction, fractionally separating aromatic polymer fraction and unpolymerized hydrocarbon fraction of successively lower boil ing ranges. ` 4. The process of converting normally gaseous hydrocarbons into low boiling liquid hydrocar bons which comprises subjecting said gas to con ditions of time, temperature, and pressure suit able for converting saturated to unsaturated hy drocarbons, separating the reaction products into 45 liquid and gaseous fractions, subjecting said gas ization zone suitable for converting a substantial boiling within the gasoline range, cooling the reaction products, separating the normally liquid 35 from the normally gaseous constituents, subject ing said normally gaseous constituents to condi tions of temperature, pressure and time, in a separate conversion zone, suitable for converting a substantial portion of said gaseous constituents 40 to unsaturated hydrocarbons, separating the re action products from said conversion- zone into normally liquid and normally gaseous constitu ents, mixing said last mentioned gaseous con stituents with said fraction^containing chiefly 45 Cz and lower hydrocarbons, and subjecting the eous fractions to high temperature and low pres sure suitable for polymerizing unsaturated hy drocarbons to liquids, separating> the reaction mixture to polymerization in a separate zone at products from the polymerization step into liq than those to which said Ca, C4 fractions are uid and gaseous fractions, combining liquid frac tions from said conversion and said polymeriza tion steps, separating dissolved gases from said combined liquids, and polymerizing « separated 55 gases at higher pressure and lower temperature vthan those to which said gaseous fractions are subjected in the ñrst polymerization step. 5. Process in accordance with claim 4 in which the second mentioned polymerization step is car 60 ried out at temperatures of 1050°--1080° F. and the ñrst mentioned polymerization step is car ried out at temperatures of 1100°-l200° F. 6. Method in accordance with claim 4 in which the incondensible gases from the second men 65 » 8. Process in accordance with claim 7 in which uncondensed gases from the polymerizing step 20 are eliminated from the system and liquefied ucts of reactio'n from said last mentioned re action zone and quenching them to inhibit the 35 the quenched products into a tar fraction, an 50 ñrst. mentioned conversion step. y chiefly C3 and C4 hydrocarbons and another frac tion containing chiefly C2 and lower hydrocar bons, subjecting said Ca, C4 fraction to conditions 30 of temperature, pressure and time in a polymer 30 tioned to a separate reaction zone wherein for '40 range, subjecting the combined fractions to con ditions of time, temperature and pressure suit able for converting saturated into unsaturated hydrocarbons, separating liquid from gaseous re action products, and subjecting the gaseous prod 10 ucts to conditions of time, temperature and pres tioned polymerization step are eliminated from the system. . ‘7. 'I'he process for obtaining liquid aromatic hydrocarbons from normally gaseous hydrocar bons, which comprises separating said'gaseous temperatures higher than and pressures lower subjected. ‘10. Apparatus for converting hydrocarbon gases to liquid hydrocarbons comprising means for separating said gases into a higher boiling and a lower boiling fraction, means for heating said higher boiling fraction, reacting means for main 55 taining said heated gases under _conversion con ditions for a period of time suiiìcient to convert gaseous hydrocarbons to liquid hydrocarbons,v means for separating reaction gases from liquids, a second heating and reacting means, means for charging said reaction gases to said second heat ing and through said second reacting means, means for separating liquid and gaseous reaction products produced in said second reacting means, a. third heating and reacting means, lmeans for 65 charging gaseous products produced in said sec ond reacting means to said third heating and through said third reacting means, and‘means for optionally charging said lower boiling fraction 70 hydrocarbons into fractions of successively lower to said second-or said third heating means. 70 boiling range, separately heating one of said» 11. Apparatus for converting hydrocarbon fractions of higher boiling range under conditions gases to lliquid hydrocarbons comprising means 0f time and pressuresuitable lfor converting gas for heating and reacting said gases, means for eous hydrocarbons into liquid hydrocarbons b_oil passing said gases through said heating and re 75 4ing within .the _gasoline range, separating theV acting means, means `for separating gasœ from 75 7 the liquid reaction products, means for cracking absorption medium, means for separating the gases, means for passing said separated gases absorbed 'constituents'irom the absorption me dium, means for- mixing separated constituents through said cracking means, means for separat ing gases and liquids issuing from said cracking Vwith said condensible products, means for sepa- . Ñmeans, a second'heating and reacting means. means for charging gases from. said cracking means to said second heating and reacting means. means for separating condensible from incon-` densible products issuing from said second react ing means, means for absorbing the heavier por tion of the incondensible products in a liquid rating normally gaseous constituents from nor mally liquid constituents rin said mixture, and means for recycling separated normally gaseous constituents to said first mentioned'heating and reacting means. HERMANN CLAUS SCHU'IT.