US1784956A - Distilling apparatus and method - Google Patents

Description

Dec. 16, 1930. E. o. BENJAMIN 1,734,956"

nxsnnuue Arrmrus AND IETHOD rind July 28; 1924 5 Sheets-Sheet 1 0/4 sI/PPLY laws/004a 0/1.

I INVENTQR o Mag min M ATTORNEY D 6, 1930. E. o. BENJAMIN 1,784,956

DIS'I'ILLING APPARATUS AND METHOD Filed July 28. 1924 5 Sheets-Sheet 2 INVENTOR 4&4 ATTORNEY 5 Sheets-Sheet 3 E. O. BENJAMIN Filed July 28, 192

DISTILLING APPARATUS AND METHOD Dec. 16, 1930.

- INVENTOR Ella/am QBe/g/a/rzzm ATTORNEY Dec, 16, 1930.

E. o. BENJAMIN DISIILLING APPARATUS AND METHOD Filed July 28, 1924 5 Sheets-Sh q ep 5 INVENTOR lflwarzl aim/(1min Ju ATTORNEY Patented Dec. 16, 1930 EDWARD O. BENJAMIN, OF NEWARK, NEW JERSEY DISTILLING APPABATD'S AND METHOD Application filed July 28, 1924. Serial No. 728,543.

M present invention is shown in a form,

particularly adapted for fractional distillation and cracking of crude petroleum to recover the various constituent fractions ineluding various grades of petroleum ethers, gasoline, etc., but it will be evident that the invention is equally applicable to petroleum from which the more volatile constituents have been skimmed and also for more accurate separation of fractional products of distillation or skimmin also that with obvious changes either 0 design or temperatures and pressures of operation, the apparatus may be em loyed for fractional distillation of any flui or even of solids suspended in a fluid medium.

As applied to mineral oils, it is a continuous process, the oil to be distilled being continuously fed into the system and the final 2 products such as separated distillates, fixed fuel gases, residuum, coke, etc., being continuously withdrawn.

The process may be-carried on at a low operating cost and with but slight heat losses. No sediment, coke or other encrustations are formed in the active parts of the apparatus and when cleaning becomes necessary, the units may be cleaned one at a time and the operation of the remaining-units need not be interrupted. By use of the process, sharp fractions are obtained and the yield is relatively high.

The apparatus which I prefer to employ for carrying out the process may be installed at a comparatively ment parts are few and inexpensive an perfect control of temperatures and pressures at all points are assured.

. As applied to the refining of mineral oils, notable features of the invention are as follows:

Oil i om the usual storage tanks um ed to an elevated reservoir which is prefera iily sealed and kept underpressure higher than plied thereby. From the reservoir the oil passes through a series of retorts each of $110- cessively lower internal pressure and higher low cost. The replace that of the highest pressure retort to' be supstant boilin point, as will be explained below. The ow throu h the successive re-- torts may be controlle b adjustable valves which are preferably di erential automatic valves adapted to operate on a pressure drop which may be adjusted to suit the conditions. The distillate from each retort passes to a separate condenser column, preferably through an adjustable relief valve of the automatic type, an important feature being that all the condensers are maintained at pressures very much less than the internal pressures of their respective retort's, whereby the hot vapors escaping from the respective retorts are abruptly and greatly expanded, thereby greatly lowering their temperatures and facilitating maximum condensation with minimum heat evolution, so that roblems of cooling or refrigeration of con ensersare sim lified and practically eliminated.

' e condensers are each at a considerably lower temperature and pressure than the retorts with which they are associated, and the condensers corresponding to the respective retorts are in a reversed order as regards internal pressures. In other words, the condenser into which the first low temperature and high pressure retort delivers is maintained at a comparatively low pressure, while the successive condensers into which the progressively higher temperature, lower pressure retorts deliver have progressively higher pressures. This causes the flow of ases and vapors through the successive con ensers to be in an opposite direction to the oil flow through the retorts. Thus, in the directionof the gas flow, there is a graduated drop in pressure and temperature in the successive condensing columns. Thus the uncondensed vaporscontinue to flow in the direction of lower pressure and temperature until each particular constituent reaches the particular 7 condenser where'it finds conditions necessary for its'liquefaction.

One feature "of the invention involves providing each condenser with a pluralityof separator pans for collecting the various grades of condensate and from which the condensate is continuously withdrawn. The vapors entering the condenser from the lower a gasometer from which end are caused'to successively flow through each of these pans .until they either condense or pass from the top ofthe condenser back -to the next adiircent lower pressure cooler condenser whic they enter midway, or at least above the lowermost of the series of pans therein. The gas which is thus circu- 'lating through the apparatus promotes fine separation of thefractions by picking up higher fractions that may be held .in: solution in lower fraction ans and causing the same to be precipitated in pans'where the temperature is lower.

- A certain amount of uncondensible gas is necessarily produced in carrying out the process, and I prefer to utilize this gas as a medium for performing several useful functions; It may be used for applying the desired pres sures in the storage tanks. retorts and condensers, for injecting lates into the retorts, for removing vapors from the retorts and carrying them through the successive condensing columnsand finally as a fuel for firing the retorts. the gas, after traveling through and having the vaporsremoved by cooling and compression, is washed to remove the water soluble constituents and then stored in it may be withdrawn the system and used as'needed.

Preferably, after 'the'crude oil has been passed through the series ofretorts and separated by! the above described refining process, the residue which remains in the last retort is deposited in a settling tank from which the residuum may be withdrawn and sprayed under pressure into a highly heated rotating coking kiln, in which the temperature is sufliciently high to cause destructive distillation of the residuum, .the products being coke, various hydrocarbons from the heavy tars, to the light oils, gases, etc. In accordance with certain features of the invention, the coke may be removed from the kiln by scrapers, and the vapors and gases may be removed and condensed. The liquid separations from. this kiln cracking process are preferably delivered back to the crude oil storage tank and again go through the process of refining. The settling tank in addition to the residuum will contain lighter grade constituents which may be tapped off for further refining and worked into paraflin wax, lubricating oils, etc.

It is to be understood that so far as the present invention is concerned, the particular number of retorts and condensers and collector pans depend entirely upon the desired fineness 'of separation, products desired and the nature of the ma terial being treated. In the case of the example shown, the ofi'takes of any or all the pans in each condensing column may be closed so that undesirable condensates will be caused to overflow as dephlegmates or refluxes, while dephlegmated distil-.

Preferably,

regulated temp the number of final the properly graded fractional distillates are being separatel withdrawn from the upper pans of each co each having the three lower I, and five of the upper pans dischar forty distinct refined separations may befi dil.

Other important features have to do with cracking. Cracking in the liquid phase occurs in the ordinary distilling retorts, but in the retorts with which I am familiar, the conditions are such that encrustations are formed on the walls, which then become very hot. These encrustations break away and suddenly expose the li uid to a very hi h temperature areas of t e wall so that the cracking is apt to be too violent, andtoo large a fraction of the cracked product is in umn. With eight condensers pans overflowing the form of permanent fuel gases, instead of this end the retort proper is in the form of a tall column of rather small or section, thereby exposing relatively great surface areato the furnace heat; Connecting the top and the bottom of this column is an exterior unheated, or at least much cooler, conduit for downflow of the liquid. Preferably, thedownflow conduit is tion than the main flow forced by boiling in the main retort column is of much higher velocity than the upflow in the main retort due to said boiling. This counteracts tendency to deposit 'en-, crustations on the relatively cool walls of the downflow conduit. In retorts where the liquid is particular] be the case with t e higher tem erature retorts near the end of the series, provide at the base of the main retort column, powerfulupwardly, directed jets whereby fixed fuel gases or steam may pressure.

Either or both of these expedients serve to of even smaller cross secfavorable to deposit of encrustations on the retort whereby the 'downviscous, as will. usually be discharged at high walls; hence the inner -wall temperature of the main retort column is not very much abovethat of the liquid so that cracking in the liquid phase is conducted at the closely the retort and is favorable to duction o'f'gasoline. There is noencrustation to break off and expose hot spots tending to produce fixed gases.

' An incidental feature for this close temperature regulation of the walls of the retort is'lo'cation of the retorts in niches out of the direct. ath of flow of flue gases andflames from t e furnace and providing independently adjustable deflectors afiordinglefiective control of flow of the heating me um into or away from the niche or recess occupied byeachjndividual retort.

erature of the bare wall ofmaximum -prooil, tends to collect in t e bottom of the respective condensers, because in general that particular condenser will be at a temperature far below the condensin point of said heavier contaminated liqui (as likewise it is above the condensing point of liquid li hter than those intended to be se arated out t erein). This undesirable con ensate in the bottom and sometimes in some'of the lower pans of each condenser is injected, as a spray, into the next retort which is of predetermined,

higher temperature than the retort from which said liquid was evaporated. This sudden spraying of theliquid into such retort of predetermined, higher temperature than the boiling point of the liquid so sprayed, results in cracking of a portion of said liquid under conditions calculated to produce maximum production of gasoline. Naturally, the portion of the liquid not so cracked distills off into the next condenser, is sprayed into the retort of the next higher temperature and so on, step by step, being thus subjected to cracking conditions at progressively .higher temperatures, and part of it being cracked in each retort, until a remnant is finally condensed in the bottom of-the condenser of. the retort of highest temperature whence it may be withdrawn for further treatment or for use as fuel. j V

The liquid for spraying into and cracking in the first or lowest temperature retort is derived from a condenser which receives the vapor escaping from the top of the condenser of the first or coolest retort, which, as we have explained, is the'last condenser from which also escapes the uncondensed product from all individual retort condensers of the serles.

The above described spraying back of the condensate is of extraordinary importance in an entirely different relations That is to say, the cruder petroleum, particularly in the first retorts of the series, frequently and usually proves extremely troublesome by reason of its tendency to emulsify and produce voluminous foam on the surface of the liquid in the retort, larger or smaller bubbles of which are apt to be carried by the draft or even to push their own way through the outlet valve, thereby contaminating with crude oil the liquid in the condenser and such contamination may and sometimes does extend to or even through the topmost pan of said condenser. The liquid which is cut back into the retort and sprayed onto the foam, is extraorj the apparatus, the dotted lines in.Figs. 1

dinarily effective in suppressing the latter,

because of itsjhigh velocity mechanical-im-.

pacts on the bubbles'and more especially because, being a thinnermore volatile liquid, it

weakens the surface tension of the bubble v films, thereby breaking the bubbles and so keeping down the foam.

It is important to note that in regulating the operation of the plant, an important objective is to utilize the distilling capacity of all of the retorts so that the amount of distillate discharged from each will be nearly the same. Hence, while each is always of lower pressure and higher temperature than the preceding retort of the series, and while the pressure differences between retorts may be more or less the same, the temperature difi'erences may be much less for the cooler retorts at the beginning of the series than for the hotter retorts toward the end of the series. The liquid being distilled may contain a very large percentage of one grade of distillate while I very deficient in some other grade. In such case, two or more adjacent retortsmay be ,run'at only sufiicient differences of pressure and temperature, to insure continued flow of the supply of oil being treated. 1

In a particular case, the pressure maintained in the elevated storage tank may be 125 pounds, the pressure in the successive retorts being respectively 115, 110, 105, 100, 95, 90, and 80 pounds above atmosphere. The temperatures, however, could be, say, 300 degrees centigrade in the first retort and say 660 degrees in the eighth, but they are not necessarily graduated proportionally for the intermediate retorts and, in general, the temperature diiferences between severalof the first retorts of the series will be much less than the difiere'nce in temperature between adjacent retorts toward the end of the series.

The expansion drop from the first retort to its condenser may be from, say, 115 pounds in the retort to, say, 40 pounds in the condenser, and the drops for the remaining retorts to their condensers will be less, the 80 pounds pressure in the last retort dropping to, say, 61 pounds in its condenser. The gas pressure line for maintaining pressure on the supply tank and for-injecting the cut.- back condensate into the retorts may be, say, 300 pounds. The eflective spray-pressure will be regulated by reducing valves and may he, say, 15 pounds above the internal pressure of the retort into which the spray is discharged.

The'above and other features of my invent-ion maybe more fully understood from the following description in connection with the accompanying drawings, in which Fig. .1 is a somewhat diagrammatic view, mainly an elevation of a portion of the apparatus;

Fig, 2 is a similar view of the remainder of and 2 indicating the line of separation;

the condensing columns;

opposite sides of the valves 17 b.

Fig. 4 is a longitudinal sectional view through one of the retorts;

Fig. 5 is an edge view of Fig. 4;

Fig. 6 is a longitudinal sectional view through one of the condenser units;

Fig. 7 is an enlarged detail view showing the1 manner'of supporting the'separator pans; an

Fig. 8 is a view in transverse section through the firebox or flue indicating the damper arrangement which controls the temperatures of the successive retorts.

Fig. 9 is a sectional detail on the line 9-9 of Fig. 4. V

F'g. 10 is a sectional detail of one of the injectors.

In Fig. 1, the elevated tank 10, sealed bya cover 11, serves asthe immediate source for supply for pressure feed of the crude oil, the oil being pumped from ordinary storage tanks (not shown) through a pipe line 14 into said tank lO until the level has been raised and the-air between the oil surface and the top of the tank has been compressed to the desired extent. A ump 13 may be utilized to lift the oil into t e tank and sediment may be drainedfrom the bottom of the tank through a drain pipe 12.

The retorts 15 are substantially identical and each includes a relatively lar e vertical portion 15d which is disposed wit a firebox or flue 16 and directly exposed to the flames and flue ases from a source of heat (not shown). Sil from the tank 10 flows down through a pipe 17 and across a main supply pipe 17a for the retorts. The supply pipe is provided adjacent each retort with a cut-off valve 17?) which is normally maintained in closed osition durin operation so that the oil ows seriall t rough the retorts by way of pipes 18 an 19 connecting the retortswith the main supply pipel 17a at e pipe 18 isthe inflow pipe to the chamber at the lower end of the retort and pipe 19 is the discharge pipe from such chamber. Valves l8 and 19' in the pipes 18 and 19 res ectively serve to control the inter-retort ow of oil. In order that pressure differences maybe maintained in the retorts I preferabl use a differential pressure valve at 19' whic may be manually regulated so .as to auto matically maintain a desired pressure differential between two adjacent retorts.

'. Valves 17 6,18, 19', are so arranged that any retort may be by-passed for purposes of cleaning or repair. Baflle plates 150 in the chambers 15b bafile direct flow of oil betweenthe inlet and. outlet ports, and the lower ends of the chambers serve as sediment collecting pockets which may be drained by cocks 15d.

Vertical pipe 15a connects at its uppenend with header comprising an elbow or other suitable coupling member 21, which in turn is connected to a spray head 22 having a dome 23 into which a spray nozzle 24 discharges. S ray head 22 connects with a second coupfiu communication at, its upper end with a pi 26 leadin to one of the condensers and at its lower em? with a reduced, elongated substantially, vertical pipe 27. The header 21, 22, 25, is of ample capacity to--provide for considerable variation in the liquid level at w. The pipe'27 is arranged exteriorly of the flue and provides a relativel downflow of oil bac to'the lower end of the retort. The oil circulation produced by convection currents is up through the hot retort pipe 15a, coupling 21, across through the spray head 22 and couplin 25 and down through the cooler pipe 27. apors distilled in the retort or mec gases escape through the pipe 26. Because of the reduced flow-section area of the pipe 27, a rapid downflow is assured, thereby preventing the retort circulation from becom: ing clogged by encrustation of solid matter formed by the evaporation and cracking process which occurs in the retort and thus also preventing the formation of a great amount of gas which would occur if the liqcooler passage for the anically entrained in the g member 25 which is in open uid were suddenly exposed to the hot wall of curs in 'each retort and is preferably regulated by adjusting the differential pressure valves 19. Level and pressure gauges. 150, 15; are preferably associated with the upper end of each retort. If the oil is unusually heavy, it may tend to sluggish circulation and to the formation of large bubbles in the upflow pipe which tend to explode at the oil surface and drive crude liquid up into the condenser. In such case I may emplo one or more gas injectors 15h (Fig. 9) disc arging into the lower end of the upflow pipe. These in'ectors effectively revent the formation of large bubbles an promote a more rapid circulation of heavy oil. The injectors .are not essential to successful operation under ordinary conditions, but may be brought into service when unusual conditions such as above described occur. They are frequently found desirable in connection with the higher temperature retorts for introducin oils; gases or other reagents for treatment 0 the mixture, as ilrtiycases where itbecomes too heavy and stic The only sections of the retorts which are directly exposed to flame and flue gases are the vertical upflow pipes 150 and in case these pipes burn out, I provide means for facilitating their rapid removal and replacement. Preferably they are mounted in magnesium, asbestos or fire clay 16a (Fi 4) removably cement ed into the roof and [Foor of the heating furnace 16. The cement may be broken- Ill) through the roof and the, insertion of a new pipe.

' The condenser unit, seen most clearly in Fig. 6, is preferably in the nature of an air cooled fractionating column 30 formed with upper and lower heads 31, 32 and supporting in superposed spaced relationship, a number of separator pans 33. Vapor escaping to these through the pipe 26 is controlled by an expansion valve 34 which operates to maintain desired pressure in the retort. The expansion valve may be of any appropriate construction, and for illustrative purposes I have disclosed a poppet valve held against a seat- 35 formed at the top of a standpipe 36 which projects through the lower head 32 of the condensing column and is suitably coupled at 38 to the pipe 26. The vapor pressure necessary to displace the valve 34 may be predetermined by adjusting the tension of spring 39. Stem 40 of the expansion valve projects into a housing 41 below the coupling member 38 and carries a head 42 oppositely acted upon by expansion springs 39 and 43. Spring 43 normally tends to seat the valve while the relatively weaker spring 39 normally tends to unseat the valve. A spring tension adjusting member 44, manually controlled by a hand wheel 45, may be utilized to decrease or increase the pressure on the spring 39 and consequently render more or less vapor pressure necessary for lifting the valve 34. The connection etween 44 and hand wheel 45 may comprise a threaded rod 45aworking in a stufiing box 456 at the lower end of a pipe 41 screwed into coupling 38 and servin as a housin for the s rm 5 and g' g p g 10)flarranged at the discharge end of thethe valve stem. The sudden expansion of the vapor escaping from the valve into the relatively low pressure condenser greatly lowers its temperature, so that air cooling is sufiicient to take care of the remnant of heat absorbed by condensing from vapor to liquid.

The separator pans 33 preferably have flanged edges 45 supported upon split locking rings 46 which are sprung into annular grooves 47 between bands 48 secured within the condensing column. The extreme overall diameters of the pans are slightly less than the internal diameter of the fixed bands 48 and the material of the locking ring 46 is thicker than the depth of groove 47, preferably about twice as thick. Thus the pans and split rings may be successively removed through the topof the condenser when the cover 31 is removed. As shown in Fig. 7,

the depending side wall of the pan locks the ring in its groove. Obviously, other expedients might be resorted to for supporting the pans. Each pan is provided with acentral tapered passageway 49 for the upflow of vapor and gas, which u on flowing through one of the openings 49 is directed back into the pan and caused to bubble up through the liquld in the pan by a hood or deflector 50,

traps 54 may be of glass or valves 56 may be three-way valves so that the'condensate, particularly of the lower pans, may be amined for quality and if this is below grade, the pan outlet may be closed by valve 56. Such pan will then overflow into the dephlegmatedliquid in the base of the condenser until such pan has been washed clean enough to yield a standard product.

The successive retorts are maintained at successively higher temperatures and the 'dephlegmated and rejected distillate from' one condenser is delivered back to the next retort. through one of the spray nozzles 24.- The spray nozzles are preferably in the form of injectors, the. injecting medium used being gas produced in the process. The methcd of producing, compressing and utilizing this gas will be more fully described hereafter. The injection of rejected distillate from one condenser ,into the next higher temperature retort serves to dissolve the foam on the liquid surface in the retort and assist in the circulation above mentioned. The spray nozzles preferably include concentric pipes for the as and oil and a conical deflector 24a (Fig;

pipes may be raised or lowered by a stem out-back oil is sprayed. Lowering of this deflector will give a large discharge annulus resulting in a coarser spray of less force and vice versa. A reducing valve 24d in the gas line and a cut-off valve 246 in the oil line to the injector are also employed. Thus spray- .ing the distillate into a retort where the temperature is higher, and the pressure is lower, than in the retort from which the distlllate was boiled off results in immediate gasifying I of a substantial percentage of said dlstlllate,

and such vaporized portion is subjected to cracking in the vapor phase while the liquld remainder of the cut-back distillate, is'redistilled along with the other liquid in said retort.

The relative pressures and resulting flow through the series ofcondensersare just the reverse of those in the retort series. The inlet pop' valve 34, of the condenser into which the last and highest temperature retort delivers, is set for the highest pressure .con-

denser so that theflow of uncondensed vapors and gases from one condenser to am other is countercurrent to the inter-retort flow of oil.i The outlet 52 of each condenser discharges through conduit 60 into one of the lower pans 33 of the next condenser near the bottom of said pan. This affords a liquid sealed trap through -'which uncondensed vapor and gas forces its way into a lower pressure condenser. It bubbles up through all of the upper separatory pans. Thus the pressure at the outlet for each pan is normally lower than that of the preceding, by an amount equal to the flow-resistance plus the depth pressures against which the. gases must be forced to reach the successive bubble outlets.

The gases and vapors from each' condenser are thus subjected to the successively lower temperatures and pressures of the five successive pans of all the successive condensers through which they must pass to reach the outlet at the end of the series. The fixed gases not only deposit condensed vapors but also tend to evaporate and carry alon fractions held by solution in pans too hot or them'to condense in. Such fractions gas and vapor are carried throu h a pipe I 61 to a heat interchanger 62rece1ving heat from the flue gases. This heat interchanger may be conveniently supported upon a chimney 63 rising from the end of flue 16 and heat from the chimney may be directed to the interchanger by the use of a damper-64. In the interchanger sudden expansion of the gases causes precipitation of much of the vapor carried thereby. Liquid condensate from the heat interchanger is cut back through a pipe '65 to the sprayhead in the first retort, as described above. Uncondensed vapors and gases pass from the heat interchanger to a cooling system including a pair of water cooled condensers 67, 67a and a barometric trap 67?) in all of which some condensation takes place and from which condensate is tapped and carried back to storage through pipes 67 0, 67d. Liquid collecting in the lower end of this condenser erably carried oif by a pipe 108 and used for maybe tapped oil? through a trapped outlet 68 and cut back either to the storage tank or to one of the retorts. Rejected condensate from the highest temperature retort is preffuel oil instead of being cut back to the system. Low grade unevaporated oil from the last high temperature retort is discliar d into a settling tank 70,- aintained at sligdi tly lower temperature. V'olatile products from the settling tank 70: assthrough pipe 71 into the condenser 0 highest boiling point. This tank is provided with a number of off-takes 72, arranged at diflerent elevations. The lighter grade oils removed through the upper off-takes may be further refined and worked into paraflin, wax, lubrieating oils, etc.

The residuum from the bottom of the settling tank is sprayed through an injector nozzle 75 into a rotating coking kiln 76. This kiln preferably has bearings in the walls of a firebox 77 and is inclined so that the products of coln'ng may be gravitationally fed toward the outlet end. Means are provided at 78 for rotating the kiln and at 79 for oppositely rotating 9, central shaft 80 carrying a plurality of scrapers 81 for removing the products of coking from the kiln walls. The temperature in the kiln is sufliciently high to cause destructive distillation and cracking of the residuum, the products being coke, various hydrocarbons from the heavy tars, greases and oil, coke oils an motor fuels to gases, including methane (CH and hydrogen. The coke scraped from the walls of the kiln is fed to the lower end thereof and dropped into a 676, may be conveniently utilized to supply the well. The hot coke on contact with the water forms sufiicient steam to afford back pressure on the'joint between rotating and non-rotating parts at thelower end of the kiln, thereby preventing inlet of air at this point. V

The contact of the steam and the heated coke produces water gas, thus adding to the fuel gases generated in the kiln' and affording pressure thereon for carrying oil vapors from the kiln through an upper outlet pipe 83. Wet-coke is removed from the well by a screw elevator 84 which carries the same to a storage bin. Gases fronr'the pipe 83 are delivered to a tank 86, where partial con= densation takes place. Uncondensed vapors are successively sprayed against a series of cooled plates 87, 88, the condensate from the tank 86 and the liquids preciptated on the plates draining into a collecting tank 89 from which the liquid maybe pumped back into the system. The gases after passing the plates 87, 88, pass to a tank 93 and are pumped into a washing tower 90, in which final cooling and removal of water soluble constituents takes place and from which the gases are carried to a gasometer 91. Uncondensed gases "from the cooling system 67, 67a, 676, are also delivered through a pipe 92 to the tank 93, from which they are pumped to the "well 82 containing water. The overflow coolmg water from the cooling system'67, 67a,

tapped by the various gas pipes to the injectors 24, these latter pipes being equipped with the aforementioned reducing valves. Branch pipes 99 and 100 from the supply i e 98 lead respectively to the upper end ls-PP of the tank 10 and to a pipe line 101 for supplying the small agitating injectors. The

gas pressure in the pipe 99 is controlled by a suitable reducing valve 102 and serves to supplement the pressure of the system caused by the gravity head and maintain the oil in tank 10 under the desired pressure. If it is desired to re-run the product from the last retort instead of passing it to.-the settling tank, it is carried directly back to stora e through a pipe 104. This pipe is normally cut off from the retorts by a valve 103 and serves to convey liquid from the collecting tank 89 back to the main source of supply.

Figure 8 is a fragmentary view of a preferred arrangement wherein two batteries of retorts are arranged within the flue. A double bank of retorts, and preferably a double set of fractionating columns, are ordinarily used in connection with a single flue I for supplying heat to the two complete sets of distilling apparatus. The inner walls of the flue are provided with opposed vertical recesses or niches 105 which accommopartially encircled by t date the vertical upflow pipe 15d of the two sets of retorts. The n flow pipes are thus he hot flue walls and the portions of the pipes which are not directly exposed to radiation from the walls are in position to be exposed directly to the flue gases. tion of heat to the various retorts so that proper temperatures may be maintained, I prefer to employ a system of dampers or deflectors 110. The dam ers are so arranged that they may cause efiection of the flue gases into the niches and completely around the upflow pipes; they may be set to entirely protect the upflow pipes from the direct heat from the gases or they may be adjusted to numerous intermediate positions to finely and accurately control the impingement of the gases on the pipes.

I have not attempted to indicate an arrangement of successive dampers suchas would be used on a series of retorts in actual use but have simply shown some of the char-' acteristic positions to which my dampers may be adjusted. I

Preferably the dampers 110 are in the form- In order to control the distribu-- of deflecting blades or plates carried upon rotatable vertical shafts 111. Preferably also two of the dampers are employed in connection with each up-flow pipe 15, one to control the entrance and the other the exit of the annular passage between the pipe and the walls of the recess in which it is located.

The shafts 111 are disposed within the flue directly in front of the entrances to the niches. The larger damper 110 associated with each retort has the blade arranged eccentrically'on the shaft 111 so that it presents a wider portion 110a toward the inlet end of the flue. Characteristic positions'of the larger dampers are indicated at a and b. At a it will be noted thatthe damper is swung so that its shorter side engages with the upflow pipe and its longer side extends to the middle of the flue. When two of the dampers are thus arranged they completely block the flue passage and direct all of the flue gases two oppositely facing niches. When the larger dampers are 1n their other extreme In position 0 the smaller dampers engage with the wall of the flue and when the larger dampers are in position a the smaller ones serve to complete the deflection of the flue gases entirely around an up-flow pipe. In other words, the flue 'gases having passed around the the entrance of the flue by the smaller dampers so that when the two dampers associated with-a single retort are in positions a, 0, the retort is heated to the greatest possible extent. The other illustrated position '03 of the smaller dampers is a neutral position, the ends of the dampers engaging with neither the retorts latter are in position b the neutral position (1 of the small dampers has a tendency to prevent any direct contact of the flue gases with the retorts. With the large dampers in'position a the neutral position of the smaller dampers serves to divide the stream of flue gases, passing some of them entirely around the retorts and permitting a. portion of the gases to escape down the flue after having passed approximately three-fourths of the way around the retorts. Quite obviously numerous combinations 'of' damper arrangements may be resorted to other than the combinations shown.

Another important feature of the damper arrangement is that they may be set to completely close in the niche of any desired reretorts are directed back toward .in a divided path around the up-flow pipes in f I i the smaller dampers are indicated at c and d.

tort or retorts, asindicated for the last or fifth pair of retorts of the series. In this same connection, I have shown how inlet ducts 105a, for. fresh air-may be arrangedextending through the walls of the flues to cool a niche and retort which has thus been cut-off, thereby putting them in condition for repairs, etc.

tort of lower pressure constant bo' 1 have been distilled and also that they chemical combination,

- It will be recognized that the feature of distilling in a series of retorts wherein each successive retort is at a lower pressure as well as higher temperature than the precedin ,is of great advantage in fractional distil ation.. It is a well known fact that in distilling mixtures of liquids of different boiling points, there is a critical percentage mixture of the liquids for each particular pressure where the two liquids have an intimate relation analogous to that of alloys of quasiin which condition the composite liquid has a definite boiling point which is not that of either of the liquids, at which boiling point the two liquids are vaporized as one, that is to say, both liquids boil ofi in a vapor containin' the same roportion as doesthe liquid. ontinuous oil-- ing .of liquids of difl'erent boiling points naturally tends to bring them to this equilibrium of constant boiling point. In the practice of my method there is this same tendency, but before the equilibrium condition is reached for the pressure in any one of the retorts, the material is discharged into a reandhigher temperaupsetting the uilibrium of g point. There ore, the more volatile liquid W111 again be boiled oflf selectively the mixture again approaching nearer and nearer to the equilibrium condition for that retort and pressure, whereupon the .liquid will pass to another retort of still lower pressureand still higher temperature, and so on through the series of retorts.

8 my present invention is shown as including. ap aratus and methods suitable for fractional distillation and cracking of crude petroleum to recover the various constituent fractions, including grades of henzine,.gasoline, naptha, etc., it will be evident that it is equally applicable to petroleum from which the more volatile constituents may be employed for cracking or fractional distillation of higher grade oils. For these reasons, it will be understood that the term oil is used in the specification and claims hereof as a word of identification for certain classes ofliquids to which the various features of my methods may prove applicable.

I claim: a

1; A process of refining oil, which includes 1 passing the oil successively through a series of retorts in each of which the 01.1 is mamtained at temperatures higher and pressures lower than in the preceding retort, conductture, thereb of the retort from ing off vapors from each retort, separately condensin constituents of such vapors, segregating t e lighter condensate and feeding heavier condensate into aretort of higher temperature and lower pressure than that. which it was derived by injector action of higher pressure gases, the differences both temperatures being substantial and continu- Ously maintained during normal operation, for the purpose described.

2. A process of refining oil, which includes passing the oil successively through a series of heated'retorts in each of which the oil is maintained at pressures lower-than those of the preceding retort, permitting escape of vapors from each retort, separately condensing fractions of such lower pressure than that of the retort from which it was derived by injector higher pressure ases.

3. A process o refining oil, which includes passing the liquid oil successively is maintained at temperatures higher and pressures lower than in the preceding retort, carrying ofi va ors from each retort separately and con ensing such vapors, and returnlng uncondensed gases to the vapor space of each retort separately, the dilferen'ces in the pressures being substantial and continuously maintained durin normal operation for the purpose describe:

4. A process of refining oil, which includes passing the oil successivelythrough of retorts ineach of which, the oil is mainvapors and spray-J mg heavier condensate back to a retort of a series in the pressures and in the action of througha series of retorts in each of which the oil tained at temperatures higher and pressures lower than in the preceding retort, condensingfractions of such vapors and spraying the heavier condensate so condensed into a succeeding retort over the surface of the oil therein by jector action of higher pressure gases, for the purpose described.

5. A process of refining oil, which includes successively passing the oil through a series of retorts .in each of which the oil is maintained at boiling points higher and pressures lower than those maintained in the preceding retort, carrying ofl' vapors from each retort and fractionally condensing such vapors, segregating the lighter condensate and spraying heavier condensate so condensed. from one retort into the retort of nexthigher temperature by injection action of higher pressure gases. l

6. A process of refiningoil, which includes passing the oil successively through a series of retorts in each of which the oil is maintained at temperatures higher and pressures lower than those of the preceding retort, carrying ofi vapors from each retort condensing such vapors, producing a rapid 011 circulation in each retort independent of the interretort circulation, and returnin uncondensed gases to the vapor space oi each retort se arately, the differences in the pressures ing substantial and continuously maintained during normal operation for the purpose described. i

7. A process of refining oil, which includes passing liquid oil successively through a se ries of retorts in each of which the oil is maintained at higher temperature and lower pressure than in the preceding retort of the series, permitting the escape of vapors from each retort and fractionally condensing such vapors, and returning uncondensed gases to the vapor space of each retort separately, the difierences in the pressures being substantial and continuously maintained during normal operation for the purpose described.

8. A process of refining oil, which consists in controlling fiow of the oil through a series of retorts which are maintained at successively higher temperatures and lower internal pressures, maintaining a relatively rapid circulation of oil by convection currents in each retort independent of the interretort flow, by providing a. separate, relatively cool down-flow path from the upper to the lower portion thereof, carrying oifvapors from each retort and condensing such vapors.

9. A process of refining oil which consists in flowing the oil through a series of retorts maintained at successively higher temperatures and lower pressures, passing the vaporized oil from each retort into an associated condenser and maintaining intercondenser tained during normal operation, for the purpose described.

, 10. A series of retorts, each retort having inlet and outlet ports 'thereinadjacent its lower end, heated up-flow and externally cooled down-flow pipes for liquid circulation, a vapor take-ofi' at the upper end of the retort and pressure operated means for regulating the escape of vapor from the retort, successive retorts of the series having their respective escape means set for successively lower pressures.

11. A retort having inlet and outlet ports therein adjacent its lower end, up-fiow and down-flow pipes for liquid. circulation and a vapor take-ofl' at the upper end of the retort, pressure operated means for regulating the escape of vapor from the retort, a gas operated injectornozzle at the upper end of the retort for injecting liquid into the retort.

12. A retort having inlet and outlet ports therein adjacent its lower end providing a sediment collecting pocket below and between them, a substantially vertical heated up-flow pipe connected" with the lower end of the retort and an unheated down-flow pipe of much smaller cross-section than the up-flow pipe delivering to the lower end of the retort.

13. A retort havin inlet and outlet ports therein adjacent its lower end providinga sediment collecting pocket below and between them, a substantiallyvertic al heated up-flow pipe connected with the lower end of the retort and an unheated down-flow pipe of much smaller cross-section than the upfiow pipe delivering to the lower end of the retort, and a bafiie plate arranged between 4 the inlet and outlet ports in the lower end of the retort.

14. Apparatus for refining oil comprising in combination a connected series of retorts ,maintained at successively higher temperatures by regulable external heating means and at lower pressures by separatel adjustable pressure relief means for eac retort,

a condenser associated with each retort and is in a reverse direction to the inter-retort oil flow, the differences both in the pressures and in the temperatures being substantial and continuously maintained during normal operation, for the purpose described.

15. Apparatus for refining oil, including in combination a connected series of retorts maintained at successively higher temperatures by regulable'external heating means and at lower pressures by separately adjustablepressure relief means for'each retort, a

condenser associated with each retort and into which vapors are boiled oli from the retorts, means for serially connecting the condensers and for so regulating condenser pressures that the intercondenser vapor flow is in a reverse direction to the inter-retort oil flow, and means for delivering the lower grade of condensate from each condenser directly back to the retorts, the differences both in the pressures and in the temperatures being substantial and continuously maintained during normal operation, for the purpose described,

16. Apparatus for refining oil, including in combination a connected series of retorts maintained at successively higher temperatures by regulable external heating means and at lower pressures by separately adjustable pressure relief means for each retort,

17. Apparatus for refining oil, including in combination a connected series of retorts maintained at successively higher temperatures b regulable external heating means and at ower pressures by separately adjust-V able pressure relief means for each retort, a condenser associated with each retort and into which-vapors are boiled oflf from the retorts, means for serially connecting the condensers and for so regulating condenser pressures that the-inter-condenser vapor flow is in a reverse direction to the inter-retort oil flow, and means for ensuring oil circulation in each retort independently of the interretort circulation, the difl'erences both in the pressures and-in the temperatures being substantial and continuously maintained during normal operation, for the purpose described.

18. A process of refining oil, which includes flowing the oil into a retort, boiling off vapor, fractionally condensing such vapor and spraying only the heavier fractions of the. condensate by injector action of higher pressure gases into a similar retort maintained at a higher temperature but lower pressure to effect cracking of such condensate.

' 19. A process of refining oil which includes flowing the oil into a retort, boiling ofi vapor, fractionally condensing such vapor and discharging only the heavier fractions of the condensate through the vapor above the liquid in another retort maintained at a higher temperature but lower pressure to effect cracking of such condensate, boiling off the vapors from the second retort and condensing art of them and passing part of them bac to the condenser of said first retort; I

20, A process of refining oil, which includes flowing the oil into successive retorts and in each retort boiling ofl vapor, fractionally condensing the vapor, injecting only the heavier fractions of the condensate by injector action of higher pressure gases under pressure into a retort maintained at a higher temperature and lower pressure than the first retort to efiect cracking of said condensate, the differences both in the pressures and in the tem eratures being substantial and continuous ymaintained durin normal operation, for the purpose descri ed.

21. A process of refining oil, including flowing the oil into successive retorts, fractionally condensing vapors generated in'each I retort, and injecting only the heavier fractions of the condensate into a succeeding retort maintained at a higher temperature and lower pressure than'the first retort by in- 'ector action of higher pressure gases wherey to efiect rapid. cracking of such conden sate, the djfierences both in the pressures and in the temperatures being substantial and continuously maintained-during normal operation, for the pn use described.

' 22.- Apparatus o the class described, in-

cluding a series of retorts, means for main taining the retorts at progressively higher temperatures conjoined with progressively lower pressuresfor the higher temperatures, a fractionating condensing column into which vapors from a lower temperature retort are delivered andv condensed, an injector for spraying heavier condensate into a higher temperature retort by injector action of higher pressure gases to effect cracking of such condensate.

23. Apparatus of the class described, including a series of retorts, means for maintaining the retorts at progressively higher temperatures conjoined -with progressively lower pressures for the higher temperatures, a fractionating condensing column into which vapors from a lower temperature re'-. tort are delivered and condensed, means for spraying heavier condensate on the surface of the liquid in a succeeding retort by injector action ofhigher pressure gases to cut the foam on the surface and to crack such con-'- densate.

24. Apparatus of the class described, including a series of retorts, means for maintaining the several retorts at progressively different pressures, a fractionating condens ing column into which vapors from a high pressure retort are delivered and condensed and means for mixing the heavier fraction of such condensate with uncondensed gases, and ejecting the mixture into a lower pressure retort to effect cracking of the condensate.

25. A process of refining oil which 'in cludes flowing the oil through a series of retorts maintained at successively higher temperatures and lower pressures, boiling ofl vapors from each retort into an associated fractional condenser maintained at considerably lower pressures and temperatures than its retort, cutting back heaviercondensate from each condenser to a retort which. is maintained at a slightly higher temperature than the boiling point of such condensate by an injector spray operated by higher pressure gases.

[26. A process of refining oil which includes flowing the oil through a series of retorts maintained at successively higher temperatures and lower pressures, boiling ofi" vapors from each retort into an associated ractional condenser maintained at considerably lower pressures and temperatures than its retort, cutting back heavier condensate from each condenser to' a retort which is maintained at a slightly higher temperature than the boiling point of such condensate and maintaining intercondenser vapor flow in a direction countercurrent to the direction of inter-retort oil'flow.

Signed at New York city, in the county of New York and Stateof New York, this th EDWARDO; BENJAMIN-,

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