Патент USA US2108395код для вставки
Feb. 15, 1938'. > _ F. w. SULLlVAN. JR. ' - 2,108,395 HYDROCARBON GONVERS ION PROCESS Filed Dec. 30, 1933 > . 2 Shgets-Shect 1 59 Preasulit 0 F r L e s 1 h J0 ‘ INVENTOR I ' ?ederzck WSaZZwazzJr ATTORNEY Feb. 15, 1938. 2,108,395 F. w. SULLIVAN. JR ' HYDROCARBON CONVERSION PROCESS 2 Sheets-Sheet 2 Filed Dec. so‘, 1933 cm». mm mu .0\\ \Qmv mvw 3/umanrE Mb 7M .\.®O,\ R B m 1w v, MW w Rd \Wn a W. k M. M L . Patented Feb.'~.l5,“ 1938 _ " ‘2,108,395; v _ UNITED‘ ‘STATES PATENT OFFICE" 2,108,395 > HYDROOARBON CONVERSION PR'OQESS ' Frederick W. Sullivan, Jrl, Hammond, Ind., as ‘signor to Standard Oil Company, Chicago, 111., I a corporation of Indiana - ‘ i " ‘ vApplication(December 30, 1933, Serial No. 704,773' 6 Claims. "(01. 196-9) vMy-invention relates to an improvementin the art of hydrocarbon conversion processes or in 1200° F. while under pressure of 750 to 3000 lbs. ' other words, to an improved process for the con- _ per sq. in. Cracked products, which may or may version of hydrocarbon gas and relatively heavy not be passed through a soaking drum, go to an hydrocarbon oils to relatively light oils of the evaporator or‘ separator maintained at relatively low pressure where tar and asphaltic materials 5 ‘gasoline‘boiling range. eliminated. The overhead products from the The commercial development of present day -' are evaporator are passed to a conventional bubble oil cracking processes has been-long andcom plex but has been characterized by relatively ‘tower which may operate at the same or lower 10 few radical changes'in the types of processes. pressure as the evaporator and from which gaso First were the simple bulk distillation processes line is eliminated as an overhead product. Heavy 10 gas oil is‘ eliminated from the bottom of the wherein relatively clean virgin charging stock bubble tower but this is not cycled in the conven tional' manner to the cracking step, although a , I distilled under pressure until the residue in the part thereof may be returned to the process (sub. 15 still became too heavy for ~_further heating with-' sequent to the heating system) as quenching oil. 15 out danger of coking. The next development was Light gas oil may be likewise eliminated from the Burton-Clark type of batch or semi-continu- ' ous process wherein, the contents of the still were an intermediate point‘ in the bubble tower and a part of this may be recycled to the cracking circulated through a tube heater instead of ap was introduced into a direct-?red shellstill and 20 plying direct heat to the shell still. Then came processes of the tube or tube and‘ drum type step whilev another part, or substantially all there of, may be utilized as quenching oil. . 20 The degraded gas oil, or the balance thereof, with "clean circulation” wherein the return of' which may have a density of 25_-30° A. P. I., is any heavy asphaltic cracked material to the then' passed to a high temperature low pressure heating section of the system was prevented. ' cracking step wherein it is cracked substantially 25 All of these processes, however, use the‘ prin ciple of recycling, i. e., of recirculation of all or completely to gases and. heavy tarry or car- 25 a substantial proportion of the insu?iciently bonaceous materials. ‘This step may be carried out in a pipe heater or in any other suitable cracked material to theheating and reaction sys type of high temperature cracker. Following ‘tem; Once-through processes have been pro suitable separation steps, the ole?nic gas from ,30 posed, and used to a certain extent commercially, the high temperature low pressure cracking step 30‘ but were'never ‘successful on a commercial scale is recycled to the inlet of the initial high pres-' ‘ - on account of the relatively low yield of gasoline sure cracking step. Selected portions of'the gas which was possible by such processes. _ ' , from the main cracking system may be joined I have discovered that by the use of elevated with the gas oil therefrom prior to the high 35 temperatures and pressures, i. e., higher tem temperature low pressure cracking step. The 35 peratures and pressures than those normally used . ' ~ in commercial cracking processes, and by the ' use of a selected charging stock I‘ may eliminate substantially all recycling ‘and nevertheless‘ ob 40' tain av high yield of gasoline. My particular dis high temperature cracking step is preferably op-‘ erated at temperatures of 1000°-1700° F. while under pressure of 0-200 lbs. per sq. in. above at mospheric. - The ole?nic gases of the high temperature 40 covery is that such a process can be operated economically on a commercial scale by separat . cracking step undergo polymerization‘ and inter action with fresh oil charged to the initial crack ing the unconverted or insuiiiciently cracked ma terial from the one -through reaction products 45 and cracking the majority of said unconverted material- to gases of an ole?ni'c character, which ,gases- are then recycled to ‘the initial ‘cracking step where polymerization and condensation to gasoline occurs. The operation of my process is $0 as follows: - ing step whereby greatly increased yields of gaso line are obtained, as compared with the ordinary once-through operation. 45 The foregoing represents a brief summary of my improved ‘process, the full and complete de— scription of_ which is as follows: In the drawing attached hereto and forming I utilize a selected-charging stock, preferably . a part of this speci?cation,'Fig. 1 is a diagram- 50 ‘gas oil of approximately 35° A. 1?. I. gravity which matic elevational view of suitable apparatus for carrying out my process in one embodiment contains substantially no previously crackedtma . terial.v In the initial cracking step the fresh thereof, and Fig. 2 ‘is a similar view of apparatus i5 charge is subjected to temperatures of 950, . for carrying out my process in analternative , embodiment thereof. ‘ k v 55 2,108,895 2 The fresh oil charging stock’ is introduced into the system through line I0 by pumping means not shown. As charging stock I use a gas oil of approximately 30‘? to 40° A. P. I. gravity but may use somewhat lighter or heavier stock, depending or I9 to serve as quenching/oil as previously de scribed, or part may be passed through valve 31 and 31a in line 38 into evaporator |5 to serve in .part on the characteristics of the crude oil Bubble tower 30 may also be provided with trap-out tray 4| from which light gas oil may be withdrawn through line 42. This light gas oil may be further treated as later described, but 10 part thereof may be pumped by pump 43 through valve 44 and cooler 44b and returned to tower 30 as re?ux or part may be passed through valves - from which the stock is derived. I preferably use virgin or uncracked gas oil, i. e., a distilled frac tionlfrom crude oil containing substantially no 10 heavy asphaltic constituents. ' The charging stock after preheating by suitable " heat interchange means not shown is introduced into the coils of heater || wherein it is heated _15 as cooling medium therein, or may be returned through valve 39 in line 40 to serve as re?ux and cooling medium in bubble tower 30. to temperatures of 950°-1200° F. while under- pres sures of 750-3000 lbs. per sq. in. The time of con tact in heater I l is ordinarily short, although heater |l may be provided with a soaking section. I may also make use of an unheated soaking drum‘ |2 following heater II. If no soaking drum is 20 used, the heated products from heater || pass directly through line i3 and valve l4 to evapo rator l5, the pressure being reduced at valve l4 to the desired evaporator pressure, which in gen eral will befrom 50 to 250 lbs. per sq. in. I'may 25 also introduce relatively'cool quenching oil from a suitable source (as later described) through line i6 and through valve l1, thus introducing the quenching oil just ahead of reducing‘ valve M, or may introduce the quenching oil through valve 30 l8 located just following valve l4. \ ' - If soaking drum I2 is used, valve I4 is closed and valves |8a and l8b- are opened in which case valve |8b functions as the pressure‘ reducing valve for bringing the pressure down to the de 35 sired evaporator pressure. In this case I may introduce. quenching oil from line l9 through valve 20 located just ahead of valve lab or through valve 2| located just subsequent to valve lab. I may also introduce all or apart of the desired quenching oil through line l6 and valve 22, which is located ahead of the soaking vdrum l2 whereby somewhat lower temperatures of 900°—l050° F. are maintained in the soaking drum II. If the soak ing drum is used ‘the hot cracked materials 45 therefrom pass through line 23 to evaporator I5.v ' 45 and 45a in line 46 to pump 41 and admixed with fresh charging stock from line H] prior to entering heater | I. A part of the oil from line 46 may also be passed through valve 48 and cooler 49 to lines It or I9 to serve as quenching oil as previously described. I _ The vapors from bubble tower 30 are con 20 densed in condenser 50 and passed through pres sure regulating valve 5| into gas separator 52 which is ordinarily operated at essentially the same pressure as bubble tower 30 so that a rela tlvely “dry” release gas may be separated through 25 line 53 and eliminated from the system, or uti lized, as later described. Condensed light prod ucts are removed from separator 52 through line 54 and may be withdrawn from the system through valve 55. I may, however, provide my 30 system with a gasoline stabilizing tower in which case the condensed light products from line 54 ‘pass through line 56 to stabilizer 51 which is provided with suitable reboiling means and re flux means whereby stabilized gasoline free from 35 undesirable ‘light constituents is ‘withdrawn through bottom offtake 58 while a relatively rich stabilizer gas is‘ eliminated overhead to line 59 and is withdrawn from the system by valve 60, or otherwise utilized as later described. 40 I The unconverted gas oil withdrawn from bub ble tower 30 through line 33 is passed through line BI. and pump 62 through low pressure high temperature heater 63. I may also pass any part of light gas oil withdrawn from tower 30 by line 45 ‘42 through valve 63a and thus to heater 63. In evaporator I5 9. pressure of 50-250 lbs. per Heater 63 is operated at temperatures of 1000 sq. in. is maintained and the temperature is‘ regu- ‘ 1700” F. and pressures of 0-200 lbs. per sq. in. lated by suitable cooling means to separate sub above atmospheric wherebythe gas oil is cracked stantially all heavy tarry materials which are substantially completely into gases of high ole removed by drawoff 24. These tarry materials ?n content plus heavy tar and carbonaceous ma may be eliminated from the system, or a part terials. Heater 53 may be of ordinary pipe heater thereof‘ may be pumped by pump 25 through cool construction as illustrated, or may be of any er 26 and passed into line l9 or line I6 to serve as other suitable construction, i. e., such as a re ~quenching oil as previously described, or part ' fractory checkerwork which is alternately heated 55 thereof may be passed through valve 21 in line by ‘direct combustion, etc. I may also withdraw 28 thus being returned to evaporator l5 to act a part of the release gas from separator 52 and as a cooling medium therein. Evaporator l5 may also be cooled by heat interchange coils with fresh charging stock orbyiother suitable means. 60 Following evaporator |5 uncondensed vapors pass through line 29 to bubble tower 30. The pressure in bubble tower 30 may be the same as in evapo rator l5 or may be regulated at some lower pres line 53 through valve 64 in line 65 and introduce same by pump 66 into heater .63 in admixture with gas oil'charged thereto. I may also pass 60 all or a part of the stablizer gas from stabilizer 51 and line 59 through valve 61 in line 68 to line 65 and pump 65 for admixture with oil charged sure by means. of valve 3| in line 29. The oper 65 ation of bubble tower 30 is conventional. Vapors to heater 63. If gas is admixed with oil charged to heater 63 I preferably preheat the gas by 65 heating or heat interchange means not shown, oiftake 32 and unconverted gas oil is drawn off at the bottom of the tower through line 33. Suit able cooling means are provided which may in 70 clude coils for heat interchange with fresh zation is promoted. This admixture of gas~with the oil charged to heater 63 not only facilitates operation of the heater by providing more com 70 plete vaporization of the charge, but also serves of desired light products are removed through charging stock. The gas oil is withdrawn through line 33, and is withdrawn from the primary crack ing system and utilized as later described, but a part thereof may be pumped by pump 34 through 75 cooler 55 and passedthrough line 35 to lines l6 prior to admixture with the oil whereby vapori as an additional source of material from which gaseous olefins may be obtained. ' Products from heater 63 are passed through line ‘69 to a suitable separator 10 which is pro 76 2,103,305 vided with suitable cooling means, not, shown, and from which tar and carbonaceous materials are removed through drawo? ‘II while gases and .vapors pass through line 12 to cooler 13 and thence through valve 14. to separator 15 wherein condensed light oils (which are formed to a small extent in - heater 63) are withdrawn through valve 16 while high‘ole?n content gases are re-' moved through line ‘I1 and valve 18 for use as ‘10 later described. I may also operate separator ‘I5 at a somewhat elevated pressure in which case valve ‘His closed and valves 19 and 80. are opened wherebythe ._ materials ‘from cooler 13 may be compressed to 15 a suitably elevated pressure of 50-1000 lbs. per 3 able fresh charging stock, I may operate my proc ass in two once-through high pressure-high tem perature stages before eliminating unconverted material and cracking same to ole?nic gases for recycling. Ordinarily -I use this type of “dual once-through” process if the charging stock grav- , ity is in the upper part 01' the range which I have previously disclosed as most suited for my process or, in other words, if the charging stock has a gravity of approximately 35° A. P. I, to 40° A. P. 1., although slightly lower or higher gravities may be permitted in some cases depending on the dis ,tilla'tion range of the charging stock and on its chemical characteristics, which latter are in gen eral determined by the crude oil from which it is .15 sq. vin. by pump 8i.’ Under these conditions the Vobtained. In this "dual once-through” modi? ‘gas separated in separator 15 will consist pri cation of my process the apparatus used is es f , marily of methane and hydrogen which may ‘be .sentially identical with that shown in the at eliminated from the system through valve 82. tached ?gure except that the gas oil eliminated 20 If the light oils present in separator 15 are not from bubble tower 30 through lines 33 and 4-2 su?icient in volume ‘to e?ect this scrubbing and (except that part. thereof which may be used as separation of methane and hydrogen from other quenching oil or recirculated for re?ux and cool- ‘ . desired gases, I may add additional scrubbing ing purposes) is passed to a second high pres ‘oil (through means not shown) to separator 15 sure-high temperature heater identical with 25, whereby this purpose is e?ected. If separator heater H, the products from this second heater 25 15 is operated at high pressure I remove_ the being passed into a separating system identical separated liquids through valve 83 in line 84 to in function with separator i5, bubble tower 30,‘ stabilizer 85 which is operated‘at lower pressure etc. (with or without intermediate passage or higher temperature to the end that light oils - through a soaking drum similar to drum ii); 30 free from desired gases are removed through oil In this case the gas oil eliminated from the sec 30 take 86while' desired olefinic gases are removed ond bubble tower (except that portion thereof through o?take 81. I e ‘which may be used as quenching oil or for re?ux The gasesproduced in heater 63 and recov or cooling purposes) is passed as previously de- I ered from separator 15 and/or stabilizer 85 will 35 ordinarily have a content of gaseous ole?ns in‘ excess of 35% by volume, and if separator 15 .is so operated as to eliminate substantial quanti ties of methane and hydrogen through vent 823 the ole?n content of the total gases may be con 40 siderably higher, approaching as much as 70% by volume. These ole?nic gases are passed through line 88 ‘and compressor 89 and are ad!‘ mixed with charging stock to the process in line It prior to heater Ii. Under the conditions pre 45 vailing in heater it these ole?nic gases are sub stantially completely converted to desired prod ucts of ‘the gasoline boiling range partly by direct polymerization and partly by complex interac tion with the gas oil undergoing cracking in heat to scribed to the low pressure-high temperature heater 63. In this case the oleiinic gases in line 88 may be pumped by pump 89 to either of the two high temperature-high pressure-heaters, or may be divided in suitable proportion between both of said heaters, in order to obtain the best balance of operating conditions and results. , In this modi iication of my process the overhead system fol lowing bubble tower 30 and the analogous bubble tower of the .second stage is ordinarily combined, i. e. vapors from both bubble towers pass through a common condensing, separating and stabilizing system and the gasoline and gas-from both stages are thereby collected as single streams. In fact I may make use of one bubble tower suitably di vided at its midpoint, the ‘cracked products from er II. I may also pass a part of the stabilizer - each stage being introduced respectively above gas from stabilizer 51 through line 59, valve 61, line ‘68 and valve 90 to join other gasesdn line M and below the middle dividing point, the tower , for treatment in heater ii. from both sections are collected in a common ‘ ‘ being so arranged that, gasoline vapors and gas Heater ii ‘is operated in the temperature and‘ stream while the gas oil or unconverted material 55 pressure ranges previously set forth, the rate at which oil is charged and the rate of heat input being such that at least 35% of the gas oil intro duced is converted to lighter products 'of the gaso line boiling range. I prefer, however, to operate 60 er such conditions that at least 45% of the gas oil is so converted. Due. to the further con-_ version of the ole?nic gases produced as previ is collected in a separate stream from each sec tion, these v,sepiau'ate streams being processed as previously described. ' For example, in the practice of this “dual once through" ~ of my pr Iunay ‘use apparatus as diagratically illustrated in t . 2 wherein all elements numbered from 11 to 90 are identical with corresponding elements simi ously‘described and to their interaction with the oil charging stock, the ?nal yields of gasoline by my process will be from 65% to 80%,the gasoline being of high quality, in particular with respect to its antiknock quality. In addition, I achieve considerable economies in operating cost since once-through” modi?cation of my process is as follows: I close valve 98in line 6! and open the excessive amount of recycling per unit of fresh 93 to the high pressure-high feed charged (which is customarily employed in larly numbered oi . i. . Referring to Fig. 2, the operation of the “dual valve $2 in line as whereby the intermediate oil ‘M ‘ ted in bubble tower 3@ it ~‘ "I through line perature heater M which operates within the sametrenge of tem present commercial processes) is ‘eliminated thus ' perature reducing the necessary size of my equipment and eliminating excessive pumping costs. In certain cases, depending largely on the quality and cracking characteristics of the avail pressure conditions previously de scribed for high pressure heater ii and wherein the oil-.is subjected to relatively high conversion to but ordinarily to a lower conversion than that carried out upon the fresh oil in'hi'gh pressure 75 8,108,395 . heater II. Following heater 9| the conversion products pass through line 95 and valve 96'to evaporator tower 91 which is operated under the same temperature and pressure conditions previ ously described for evaporator IS, the pressure on the conversion products beingv appropriately re duced at valve 96. By closing valve 95 and open ing valve 98 the conversion products may be passed through reaction chamber 99 which is sim ‘ .10 ilar in construction and.- operation to previously 2. A hydrocarbon conversion process compris ing subjecting relatively high-boiling hfdrocar bon oil to cracking at elevated temperatures and pressures to convert a substantial portion there of ' into hydrocarbons oi the gasoline boiling range, separating the cracked products into tar and vapors, fractionating said vapors to recover a condensate oil heavier than gasoline and said hydrocarbons oi’ the gasoline boiling range, sub jecting said condensate oil in a second cracking 10 step at elevated temperatures and pressures to convert a substantial proportion thereof to hy drocarbons of the gasoline boiling range, sep arating the cracked products into tar and vapors, described reaction chamber I2, and in this case the- pressure is reduced at valve I00 prior to the products entering evaporator tower 91. From i evaporator 91 heavy residual products are with 15 drawn from the system through valved line IIII - Iractionating said vapors torecover a second con _ while vapors pass overhead through line I02 and valve I09 prior to entering bubble tower I04, which is operated similarly to bubble tower, 30 previously described.~ Vapors from bubbletower' 20 I04 pass through line- I05 and join vapors pro densate oil and said last-mentioned hydrocarbons of the gasoline boiling range, subjecting said second condensate oil in a separate zone to crack ing at higher temperatures and relatively low pressures to convert said second condensate oil 20 duced in the first cracking step at the vapor exit primarily to normally gaseous hydrocarbons of relatively high ole?nic content and heavy tarry from previously described bubble tower 30. In like material, and returning ole?nic gases thus termediate oils from bubble tower I04 are with drawn from the bottom through line I06 and are produced to the initial cracking step for conver 25 sent by pump III‘I through line I09 and valve I09 ,sion into normally liquid hydrocarbons in the presence of said oil. ' to the entrance of low pressure heater 63 previ 3. A process in accordance with claim 1 where ously described wherein these oils are converted to ole?nic gases. These ole?nic gases so produced ’ in normally gaseous hydrocarbons are separated after separation, etc., as previously described, may from the hydrocarbons lot the gasoline boiling diverted through valve III in line “2 whereby gaseous hydrocarbons are admixed with said con range resulting from said ?rst-mentioned crack 30 pass through valve III! in line 80 to heater II as previously described or may wholly or in part be ‘ ing operation and at least a part of said normally said ole?nic gases are passed to the inlet of the second stage high pressure oil heater 94. The foregoing being a full and complete de scription of my invention, I claim: densate oil undergoing conversion primarily to normally gaseous hydrocarbons of relatively high ole?nic content and heavy tarry-like material. ' 1. A‘ hydrocarbon conversion process compris ing‘subjecting relatively high-boiling hydrocar bon oil to cracking at elevated temperatures and 40 pressures to convert a substantial portion there of into hydrocarbons of the gasoline boiling range, separating the cracked products into tar 4. A process in accordance with claim 1 where in hydrogen and methane are separated from the hydrocarbons of relatively high ole?nic con tent prior to the return thereof to the initial cracking step. 40 5. A process in accordance with claim 1 where in the relatively high-boiling hydrocarbon oil is and vapors, fractionating said vapors to recover a distillate oil containing substantially no as a condensate oil heavier than gasoline ‘and said ' phaltic constituents and substantially no previ- . ously cracked constituents and is converted into jecting said condensate oil in a separate zone to ' at least 35% of hydrocarbons of the'gasoline boil cracking at higher temperatures and relatively ing range in passing once through the conver sion zone. ‘ low pressures to convert said condensate oil pri 6. A process in accordance with claim 1 where marily to normally gaseous hydrocarbons of rela tively high ole?nic content and heavy tarry-like ‘ g in said condensate oil is subjected to a cracking 50 temperature of about l000°-1700° F. while under material, and returning ole?nic gases thus pro > duced to the initial cracking step for conversion a pressure 01' about 0-200 lbs. per square inch. hydrocarbons of the gasoline boiling range, sub into normally liquid hydrocarbons in the presence of said oil. FREDERICK W. SULLIVAN, JR.