Патент USA US2113816код для вставки
April 12, 1938- c. w. SAACKE 2,113,816 PROCESS OF TREATMENT OF HYDROCARBON OIL Filed Oct. 18, 1934 mwmm. CHARLES n4 s/mcnz BY A TTORNEY 2,113,816 Patented Apr. 12, 1938 UNITED STATES PATENT OFFICE , 2,113,816 PROCESS OF TREATMENT OF HYDRO C‘ARBON OIL Charles W. Saacke, New York, N. Y., assignor to Gasoline Products Company, Inc., Newark, N. J., a corporation of Delaware Application October 18, 1934, Serial No. 748,823 2 Claims. This invention relates to processes and appa ratus for the production of gasoline or other relatively light distillate from raw crude oil, or other similar relatively heavy stock containing 5 lighter and heavier constituents. ing a heavy gas oil distillate derived from the other cracking steps, under the condition best suited for the conversion of this heavy gas oil stock. 5 In the treatment of raw crude oil or the like The above mentioned and further objects and to produce gasoline, it has been the general prac— tice heretofore to form from the crude oil, either by distillation alone or distillation coupled with advantages of my invention and the manner of obtaining them will be made clear in the follow '10 mild cracking, a distillate stock suitable for charging to a cracking operation, this stock 1 (Cl. 196-48) value to the desired point, and separately crack usually being a gas oil. Simultaneously, a plu rality of other cuts have customarily been re moved from the crude charging stock, being, for example, a light naphtha cut or virgin gasoline, heavy naphtha which it is desired to reform, kerosene and in some cases furnace oil, for sale as products without further conversion. After these several cuts have been obtained, it has 20 been customary to subject the gas oil to cracking in a separate unit, wherein it is converted to gasoline or other desired light distillates, and to reform the heavy naphtha separately in still an other operation. In certain instances the re 25 duced crude freed of the distillate stock men tioned, has been cracked under low crack per pass conditions to reduce its viscosity by the formation of additional quantities of gas oil suit able for cracking in a separate gas oil cracking - 30 step. It is an object of my invention to provide a unitary process for the treatment of raw crude ing description taken in conjunction with the accompanying drawing. 10 The single ?gure of the drawing represents diagrammatically in side elevation and partly in section a combination cracking unit constructed in accordance with my invention. Referring more particularly to the drawing, 15 reference numeral I indicates a crude flash tower, 2 an evaporator, 3 a viscosity breaking furnace, 4 a vapor phase furnace, 5 a soaking drum and B, a fractionator. Fresh heavy charging stock, such as crude oil, 20 after preliminary heating to a distilling tempera ture, for example, by indirect heat exchange with hot products resulting from subsequent cracking steps, or after having been heated in a directly ?red coil, or both, is forced through charging 25 line ‘i by pump 8 into the ?rst stripping section 9 of the crude ?ash tower or stripping tower I, wherein lighter constituents thereof are sepa rated as vapors and passed off through vapor line it and condenser II into receiving drum I2, the 30 condensate collected in the receiving drum be ing, for example, light naphtha or low end point virgin gasoline. The unvaporized liquid collect oil or the like whereby all the operations neces sary to produce a maximum amount of gasoline ' ing in the base of the section 9 travels down 35 of ?nal desired end point and characteristics wardly through pipe I3, into the intermediate 35 portion of the second section I4 of the crude may be carried out at the same time in a series of interlocking steps so related, one to another, flash tower, wherein a further separation into that a minimum amount of heat and attention vapors and liquids takes place, by the contacting are necessary, and high ef?ciency results. By of the introduced liquid with a stream of highly heated vapors passing upwardly through the 40 section M, as will be explained more fully here inafter. This separation may be further aided, if desired, by a reduction in pressure obtained by adjustment of valve I5. The vapors generated travel upwardly through the section I4, and those 45 remaining uncondensed at the top of this section pass oif through vapor line I6 and condenser I'I the process. I into receiver I8, the distillate so collected being, More speci?cally, it is an object of my inven tion to combine in a single unitary process for the > for example, heavy naphtha which it is desired 50 treatment of raw crude oil, the steps of topping to reform. An intermediate condensate collects 50 the raw crude, viscosity breaking the topped on trap-out tray I9, and is forced by pump 20 through line 2i into the top of the evaporator crude, cracking a clean condensate stock, includ 40 combining all of the various steps which have -heretofore been performed individually or in some incomplete combination, it is possible to utilize more advantageously heat which might votherwise be wasted, and also keep at a low ?g ‘.15 ure the amount of'labor and supervision neces sary in the operation of a system to carry out ing cracked and virgin components, derived from 2 or into the bubble tower or fractionator 6 the process, reforming any necessary portion of, through line 22, or both. The intermediate dis tillate so introduced into the evaporator and/or 55 65 the gasoline produced to raise its anti-knock 2 " , 2,118,816 fractionator serve as a re?uxing medium, and is at the same time placed in a position for cir culation through the vapor phase cracking fur nace 5%, as will be explained more fully herein after. The unvaporized liquid collects on trap out tray 23, from which it may be withdrawn through pipe 24. The several sections of the crude ?ash tower or stripper l are provided with bubble trays, 10 baifles or other contacting means, as shown in the drawing, in accordance with the usual prac tice. The lower portion of the section i4 serves as a tar ?ashing chamber, as will be explained hereinafter. 15 , . Reference numerals 25, 26'and 21 indicate re ?uxing lines through which cool oil from an ex pressure control valve 42, into the lower portion of the evaporator 2, wherein these products un dergo separation into vapors and liquid residue, just as described in connection with the cracked oil from the viscosity breaking furnace 3, The soaker 5 may be by-passed, if desired, in which case the cracked oil from the heating coil 39 would pass directly into the evaporator 2. The heavy naphtha collected in the receiver I8 is directed through the conduit 43, under pressure 10 generated by pump 44, through the naphtha re forming coil 45 located in the vapor phase fur nace 4, wherein the naphtha is raised to a high cracking temperature sui?cient to cause the con version thereof into higher anti-knock gasoline 15 components. The resulting reformed products ternal source may be introduced for cooling and are transferred from the coil 45 through the line re?uxing purposes in the well known manner. 45, having pressure control valve 41, into the lower portion of the evaporator 2. Alternatively, indirect cooling coils may be placed in the tower l, to accomplish the same purpose, or cooling may be supplied in any well known manner. The unvaporized liquid reduced crude is with drawn from the trap-out tray 23 through con 25 duit Eli, and forced by pump 28 through the heat ing coil located in the viscosity breaking furnace 3, from which the oil emerges, after having been raised to cracking temperature and cracked sui? ciently to produce additional quantities of light clean gas oil stock, suitable for cracking in the vapor phase, and is forwarded through transfer line 29 into the lower portion of evaporator 2, wherein separation of vapors from liquid residue takes place. Valve 39 is inserted in the transfer 35 line 29 to control the relative pressures in the viscosity breaking furnace and evaporator. The vapors pass upwardly through the evaporator, undergoing ‘partial condensation therein, this condensation being only sufficient to condense the 40 heavier gas oil components thereof, the vapors remaining uncondensed passing oif through con duit 3i and partial condenser 32, into the lower portion of the bubble tower 6. Condensate formed in the’ partial condenser 32 may be returned through conduit 33 to the top of the evaporator Z’asa re?uxing medium. The partial condenser may be omitted if desired. vapors and liquids, similarly to the cracked prod- __ __ '35 ucts already discussed. A re?uxing line 55 is shown for supplying cool ing ?uid from an external source to the evapo rator 2 and another line 55 is shown for provid ing cooling ?uid to the top ofthe fractionator 6, in well known manner. Indirect cooling coils might be used for accomplishing the same pur pose, in which event the cooling ?uid might be the fresh charging stock, whereby the charging stock would be raised in temperature to aid in the distillation thereof. The evaporator 2 is provided with ba?ie plates, bubble trays, or other suit able contacting means in a well known manner. 7 'In the fractionator or bubble tower, 6, the va pors pass upwardly and are subjected to frac tionation in the well known manner. A heavy gas oil condensate is collected on the 20 trap-out tray 48 located in an intermediate level in the evaporator 2, is withdrawn through pipe 49, into accumulator 5t, from which it is with drawn by pump 5i and forced through cracking coil 52 located in the vapor phase furnace 4. In 25 this coil the oil is raised to cracking temperature and subjected to conversion into lighter products, including lighter gas oil suitable for cracking at higher temperatures in the vapor phase cracking coil 39. The resulting cracked products pass "30 through the transfer line 53,. having pressure control valve 54, into the lower portion of the evaporator 2, and therein undergo separation into Gasoline vapors remaining uncondensed at the top of the fractionator are withdrawn through pipe 34 and condenser 35, the condensate formed being col lected in receiver 35. This condensate will be gasoline of the desired end point. vIt may be used by itself, or it may be combined with the light naphtha derived from the crude ?ashing oper ation and collected in the receiver !2. Either or both of these distillates may be stabilized, if de sired, or be subjected to any other suitable treat ment to give them the selected characteristics. Re?ux condensate collects in the base of the bubble tower 6, is removed through conduit 31, and passed by pump 38 through the cracking coil 39. of the vapor phase furnace 4!, wherein it is raised to a cracking temperature and subjected to conversion, preferably in the vapor phase. The resultingcracked products emerge from the heat ing coil and travel through transfer line 40 into 70 the soaker or reaction chamber 5, wherein they I have indicated all of the cracked products from the several cracking and reforming coils 39, 45 and 53, as entering the evaporator 2 through a common connection. Instead all of the pipes 4|, I16 and '53 might connect separately with the evap orator. Cooling oil can be introduced into the soaker adjacent the outlet thereof and likewise into the various transfer lines, for ?uxing pur poses, in a well known manner, if desired, so as to inhibit the deposition of coke. Likewise any suit able cooling arrangement may be provided for maintaining the temperature of the liquid coi lecting in the base of the evaporator 2 at a suit 60 ably low value to prevent deleterious coke deposi tion therein. ' The liquid residue collecting in the base of evaporator 2 is withdrawn through conduit 51, ‘ having pressure reducing valve 58, and is. intro duced into the base of the lower section M of the crude ?ash tower i, which base serves as a tar ?asher drum. Therein the introduced resi due undergoes separation into vapors and un vaporized residual stock or tar, by virtue of its 70 heating coil. The digested products emerge from contained heat, and the reduction in pressure ef fected by aid of valve 58. The vapors pass up wardly through the tower l, constituting a source of the hot vapors already mentioned, which con 75 the soaker and travel through conduit El having tact with the partially reduced crude charging undergo further conversion as a result of their contained heat, preferably under substantially the same pressure as held on the outlet of the 75 2,113,816 stock moving downwardly through the lower portion I4 of the tower, after introduction there into through the aid of conduit I3. Reference numeral 60 indicates a valved line interconnecting the transfer line 29 with the base of the tower I whereby any desired portion of the densate, these condensates corresponding respec tively to the condensates collected in the base of the fractionator 6 and the gasoline distillate so segregated can then be combined, either with or without previous reformation, with the cracked hot products from the viscosity breaking furnace gasoline collected in receiver 36 and/or the virgin coil may be introduced directly into the crude light naphtha collected in receiver I2, to form a desired blended product. The heavier condensate obtained can be introduced into the top of the 10 evaporator 2 above the tray 48, and the lighter clean condensate can be introduced into the base of the fractionator 6, or, if desired, both stocks might be introduced into the evaporator above the tray 48, or part or all ‘below the tray 48 if 15 desired, for cooling purposes. In any event the effect would be to cause the heavy condensate to pass through the heating coil 52 and the lighter condensate to pass through the heating coil 39. ‘The same effect might be obtained by passing 20 both the light and heavy condensates directly into the charging lines 49 and 31, respectively, of the two cracking coils mentioned. In case the vapors from the separate viscosity breaker evapo stripping system along with the liquid residue ‘a-n.’ 3 able for vapor phase cracking, and heavier con 10 from the evaporator 2, in order to supplyv any additional heat necessary for the ?nal stripping of the crude charging stock. ' All desirably light cracking stock contained in the residue introduced into the base of section 14, 15 including any naphtha components, is volatilized, while the undesirably heavy constituents remain in unvaporized form and are withdrawn from the process through valved draw-off line 59. The heaviest fractions of the generated vapors are 20 ‘condensed and collected on trap-out tray 23 for recycling through the viscosity breaking furnace 3, while somewhat lighter constituents collect on trap-out tray l9, and are returned to either the evaporator or the fractionator or both, in which 25 event they are recycled through the vapor phase cracking coil 39, in the furnace 4, along with the other re?ux condensate collected in the base of the fractionator 6. Any naphtha components contained in the rising vapors ‘are withdrawn 30 through connection 16 and condenser I‘! for col lection in the receiver l8, and for ‘recycling through the reforming coil 45, in the vapor phase furnace 4. ' rator are fractionated, the pressure in the evap 25 orator last mentioned can be considerably lower than that in the evaporator 2, since the con densate stocks obtained can be pumped to their destinations at increased pressure. On the other hand if the pressure in the viscosity breaker 30 evaporator is maintained su?iciently high the vapors therefrom can be introduced directly into the evaporator 2 under their own pressure. By utilizing two separate evaporators it is pos By providing the several cracking coils shown, ' 35 it is possible to effect the desired conversion of sible separately to extract from the process tar 35 the several oil components under the optimum conditions. The inclusion of the trap-out tray 48 and the associated heating coil 52 assures that the heavy gas oil, which is not suitable for crack ing in the vapor phase furnace on account of coke forming tendencies, can be separately con verted under the conditions best adapted to cause a maximum conversion thereof, without being returned to the viscosity breaking furnace 3, for 45 conversion with the reduced crude at correspond ingly lower conversions per pass. The provision of the cracking coil 52 also lightens the load on the viscosity breaking furnace 3 and .not only permits greater through-put or reduced crude in that furnace, but also limits the stock going through that furnace to a greater proportion of virgin components and to components which are more nearly of like characteristics. The viscosity breaking furnace 3 can, therefore, be operated 55 under the best conditions for cracking the heavy reduced crude, while the heavy cracked con densate collected on trap-out tray 48 may be separately converted under conditions best suited to its characteristics, the clean gas oil cracking 60 stock from the base of the fractionator and the heavy naphtha from the crude ?ash tower being separately treated in individual furnace coils, to cause the desired conversion thereof, under con ditions properly selected for the stocks in ques 65 tion, without consideration for other of the frac tions. If desired the cracked products from the vis cosity breaking furnace may be introduced into a separate evaporator, and only the Vapors be 70 passed to the evaporator 2, part of these being diverted to the base of the tower l to supply additional heat, if desired. Or alternatively the vapors from the added evaporator may be sepa rately fractionated in order to form gasoline 75 distillate and light clean gas oil condensate suit from the viscosity breaking operation, and from the cracking and reforming operations, these two tars having di?’erent characteristics, several different types of marketable fuel oil can be formed by properly blending them, or the two 40 tars’ may be sold separately if desired. The sug gested additional evaporator, fractionator, and associated pipe lines have been omitted from the drawing. Referring speci?cally to the furnaces 3 and 4, 45 it will be noted that the stock to be subjected to viscosity breaking cracking is ?rst passed through tubes in a convection section of the furnace, then through tubes located in the radiant portion of the furnace, and finally through soaking tubes 50 located in the cooler convection section of the fur nace. The relatively light clean gas oil removed from the base of the fractionator is preferably cracked by passage entirely through radiantly heated tubes located in one of the two radiant 55 or combustion sections of the twin ?re box type furnace 4. The heavy gas oil withdrawn from trap-out tray 48 is preferably passed through a similarly located coil 52 in the other radiant section of the furnace 4, while the naphtha from 60 the receiver IB ?rst is conducted through the convection section of the furnace, and then through roof tubes in the radiant section of the furnace, 4. Obviously other flow arrangements might be used, and other types of furnaces, like 65 wise. The heating tubes could, if desired, be lo cated each in a separate furnace, although the arrangement shown is preferred. From a relative point of ‘view, the cracking conditions on the stock charged to the viscosity 70 breaking furnace 3, the cracking coil 52, the cracking coil 39, and the reforming coil 45, will be increasingly more drastic in the order men tioned. Merely by way of example, the outlet temperature of the heating furnace 3 may be 75 4 2,113,816 890° F., more or less, the outlettemperature of the coil 52, 940° F., more or less, the outlet tem perature of the coil 39, 975° F., more or less, and the. outlet temperature on the reforming coil 45 may be 1050° F., more or less. I prefer to use the temperatures and pressures and temperature controllers, and other auxiliary apparatus have been omitted from the drawing in the interest of clarity, but could be provided in accordance with the teachings of the prior art. While I have described a particular embodi- ~ ment of my invention, for the purposes of illus already mentioned, for the viscosity breaking, cracking and reforming operations, particularly tration, it should be understood that various modi?cations and adaptations thereof, occurring for producing gasoline'of approximately 70 oo 10 tane number from a charging stock such as 37° A. P. I. Mid-Continent crude, but somewhat to one skilled in the art, may be made within the spirit of the invention, as set forth in the ap higher or lower temperatures and pressures may be used, the exact conditions being determined in each case by the character of the charging stock and the speci?cations of the ?nal desired products. The octane number and other charac teristics of the ?nal desired product may be reg pended claims. I claim: ' ' . 1. The process of treating hydrocarbon oil which comprises separating from raw crude oil light and heavy virgin naphtha and topped crude, cracking said topped crude, reforming said heavy The outlet pressures on all of the heating coils naphtha, contacting vapors from a portion of the cracked topped crude with said raw crude oil to aid in the said separating step, combining another portion of the cracked topped crude with the re formed products and separating from the com may be substantially the same, this being su?i cient to maintain. a pressure in the evaporator of bined products a gasoline distillate, a gas oil con densate suitable for use as vapor phase cracking ulated by varying the cracking temperature, the cracking per pass of the individual stocks, or the "20 total amount of cracking of these stocks; 7 about 200 pounds per square inch, the pressure in a stock andaheavier condensate, cracking said con the soaker 5 being slightly higher, and that in the bubble tower or fractionator 6 being slightly densates last-mentioned in separate cracking "’ zones and'combining the resulting products with said cracked and reformed products ?rst-men lower. These pressures may, if desired, be dif ferent, the necessary differential being main-, tioned prior to the separation thereof into said tained by adjustment of the pressure control gasoline distillate and said condensates. 2. The process of treating hydrocarbon oil valves in the transfer lines. . - It is sometimes advantageous to increase the pressure on the reforming coil 45, for example by several hundred pounds, to a value in the neighborhood of from 500 to 700 pounds per square'inch more or less. The pressures on the outlets of the other coils may similarly vary from a few pounds to several hundred pounds per square inch, but in general the pressure condi tions speci?cally mentioned are desirable. 11.0 Similarly the temperatures may vary quite widely, depending upon factors such as thechar acter of the stock and the character of the ?nal desired product. As a rule it is not possible to state exact ‘temperatures, but as a general prop osition the outlet temperature of the viscosity breaking furnace coil may fall in the range of 840° to 900° F., the outlet temperature of the vapor phase coil 39 mayfall in the range of 850° to 1000° F. and the outlet of the reformer coil 50 may fall in the range of 1000° to 1100° F. The outlet temperature of the heavy gas oil crack ing coil 45 would desirably fall in between that of the viscosity breaking heating coil, and the vapor phase cracking coil, being, for example, in 55 the range of 850° to 925° F. The amount of con version to products in the gasoline boiling range per pass may be from 6% to 15%, in the viscosity breaking coil desirably about 10%; 10% to 20% in the heavy gas oil cracking coil 52, preferably 60 about 15%; and 15% to 25% in the vapor phase cracking coil and soaking drum, preferably about 20%. These conversions per pass are merely in tended for general guidance, and are not inserted in a limiting sense. Various valves shown on the drawing, but not referred to de?nitely by reference numerals, are intended for. obvious control purposes. Aux iliary heat exchanges, cooling coils, pressure, flow which, comprises introducing relatively heavy charging stock comprising crude oil components into a primary fractionating zone of a stripping zone in countercurrent contact with a rising stream of highly heated vapors, removing from the primary fractionating zone unvaporized por tions of the said charging stock and condensed fractions of the rising vapors, passing oil so re moved in a stream of restricted cross sectional area through a heating zone wherein it is raised to a cracking temperature by passing successively through convectively and radiantly heated zones and subjected to'conversion, introducing a portion of the resulting cracked products into an evapo rating zone wherein vapors separate from liquid ' residue, fractionally condensing resulting vapors to form 'a desired gasoline distillate, a relatively light gas oil condensate and a relatively heavy gas oil condensate, passing said gas oil con densates through separate heating zones in v50 streams of restricted cross sectional area and therein raising said oils to cracking temperature substantially only by the application of radiant heat and causing conversion thereof, introducing the resulting cracked products into said evaporat ing ‘ zone, removing liquid residue from said evaporating zone and introducing it into said stripping zone, with an accompanying reduction in pressure to cause the ?ashing of lighter con stituents therefrom asgvapors, the resulting vapors passing to said primary fractionating zone to con stitute a source of said highly heated vapors ?rst mentioned and introducing another portion of the hot cracked products from said heating ?rst mentioned into said stripping zone to serve as an ' additional source, of said highly heated vapors first mentioned. , CHARLES W. SAACKE.