US1852184A - Petroleum refining apparatus - Google Patents

Description

April 5, 1932.

Jil

F. A. MILLI'FF ET Al.

PETROLEUM REFINING Original Filed Jan.

APPARATUS '7 Sheets-Sheet. 2

Z55 25a (D Q and m NUI/ff,

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April 5, 1932. F. A. MILLIFF ET AL 1,852,184

PETROLEUM REFINING APPARATUS Originl Filed Jan. l1, 1926 7 Sheets-Sheet 5 liz Ao/wey.

April 5, 1932. F. A. MlLLlFF ET AL 1,852,184

PETROLEUM REFINING APPARATUS Original Filed Jan. 1l. 1926 7 Sheets-Sheet 4 I l l l l l l l I l April 5, 1932. 1,852,184

F. A. MILLIFF ET AL PETROLEUM REFINING APPARATUS Original Filed Jan. 11. 1926 7 Sheets-Sheet 5 April 5, 1932. v F. A. MILLIFF ET AL 1,352,184

PETROLEUM REFINING APPARATUS Original Fled Jan. 11. 1926 7 Sheets-Sheet 6 orwey.

Apil 5, 1932.

1M /pjyfj F, A. MILLIFF ET AL PETROLEUM REFINING APPARATUS Original Filed Jan. l1. 1926 l 7j@ Z0 7 Sheets-Sheet '7 Patented Apr. 5, 1932 .eineres Parent;

erica PETRLEUM RLEIFILCIIWG APPARATUS Appleatonvlefl January 11, i526, Serial No. 80,583. ReneWed`Dece1nber 27, 1928.

Our invention relates to petroleum'reiining apparatus and includes a novel form of fractionating tower.

In yone of the'more modern methods of refining petroleum oil, the crude oil is heated in a pipe still up to about 500 F. The hot crude eil is then conducted from the still to a vaporizer in which the more volatile hydron carbons are separated from the residuum as vapors. The mixture of these vapors so separatedis then conducted through adephlegmator which cools the vapor mixture to a point where a certain group of the less volatile hydrocarbon lvapors condense and are removed from the vapory mixture. Theremainder of the vapor mixtureV goes tol a second dephlegmator, where it is further cooled', and another group of the remaining hydro-l carbon vapors are condensed Aand removed from the mixture. In the same manner the remainder of the vapor mixture is progres,- sively cooled and condensed in furthery de'- phlegmators. In the present practicel a total of six dephlegmators is generally used, the vapor mixture which leaves vthe last dephlegmator being completely condensed in a condenser. Eachoi' the groups of hydrocarbons which a series of dephlegmators thus separates out from the vapor mixture may comprise a commercial'produ'caor itmay be further refined. In order oftheirboiling points, and, hence, in the order in which they are condensed from the vapor mixture, these productsarecommonly termedgas oil, stove oil, several grades of distillate,ker0sene and gasoline.

Inasmuch as the same relinery mayiind itA necessary to purchase crude petroleum, com.- posed of various proportions of Ahydrocar- Vbons,oit is'very desirablethatvin a refining process such as just described, complete control of the temperatures of condensation may be possible in each stage of reduction of the vapor mixture into liquidhydrocarbon prod` ucts. It is alsodesirable to effect anecono-` my; in first cost of constructionV and'm the cost of operation of such a fractional distil? lation apparatus.

It is an obiect of our invention, therefore,

-to oro. .de a sinele fractionatino tower which l c C Yvolatile than those desired in the takes the place of the several dephlegmators and accomplishes a separation of the several hydrocarbon. products enumerated above from a mixture of their vapors.

It is also an object of our invention to provide in such a ractionating tower a series of vapor condensing sections, the temperature of each ci' which is controllable vso that as the vapor mixture passes through it a predetermined'group of hydrocarbonsis con-'g densed therein.

Itis another object of our invention to provide in such a ra'ctionating tower a re-boiler associated vwith each vapor condensingsection in whichthe condensate fromy that section is re-.boiled to drive oil' any hydrocarbons condensed in that section which are more product to he removed therein. n y It is a still` turtherob-ject of our invention to provide in saidvapor ,condensing sections novel condensatepans having vaporizer passageways therein and caps for downwardly detlecting the vapor rising through these passageways, so that when condensate stands at a certain level in said pans the vapor will be forced kto bubble through the condensate in order to escape upwardly.

Ano-ther object of our invention is to provide means for equally distributingthe vapor through the condensate along the Whole length of these caps on each side thereof.

Still another object is to provide means for\cleter1niningthe level-of condensate in each pan,.and hencefthe depth below the sur-' tace of the condensate at which the va-porsis released. i A further object of ourfinvention isto provide means for conductingthe overflowl ci condensatefromeach pan to the onenext below it anda novel and eiiicient means of intro. ducinga liquid hydrocarbon retluxfintofth'e condensate so that it will be thoroughly mixed, v therewith as itenters the lower pan. y

Anotherobjectds to provide the re-boilers with heat exchange elements whic-hare supplied through piping with a heating` medium, such as hot residum, in such a manner thatf these heat exchangers may communicatein parallel fashion between the hot .residuumY supply and cool residuum return lines, or else they may be connected together so that all the residuum passes into the lower heat exchanger and from it to the one next above it, and so on up in series to the uppermost heat exchanger which has outlet connection with the cool residuum return lines.

Yet anotherobject of our invention is to .provide a novel condensate tap from each reboiler whereby the condensate is drawn from a lower level of the re-boile'r` and yet whereby the surface of the condensate is maintained at a predetermined level in the re-boiler.

It is a further object to provide a re-boiler for each condensing section in which the condensate from that section may be treated by means for applying dry heat thereto or by means for releasing steam therein.

Another object of our invention is to provide means for cooling allof the re-boilers when a drop in temperature becomes necessary.r A Other objects and advantages of our invention will be made apparent in the following specification and in the,accompanyingdrawings, in which Y Fig.-1 is a diagrammatic view showing our fractionatin tower employed in aV typical apparatus for refining petroleum.

Fig. 2 is a fragmentaryelevational view of our fractionating tower taken in the direction of the arrow 2 in Fig. 3.

Fig. 3 is a fragmentary elevational view o-f our fractionating tower taken in the direction of the arrow 3 in Fig. 2.

Fig. 4 is a fragmentary vertical sectional view taken on the line 4-4 of Fig. 3.

Fig. 5 is a plan view of one of the condensing section pans of our invention with the caps partially broken away to show the riser openings in the pan.

Fig. 6 is a vertical :sectional view Vtaken on the line 6 6 of Fig. 5 and showing a pan' condensate discharge pipe with a refiux discharge pipe centrally disposed therein.

- Fig. 7 is a fragmentary vertical sectional View taken on the line 7-7 of Fig. 5 and showing a' pan condensate collector pipe.

Fig.- 8 is a fragmentaryvertical sectional view taken on 4the line 8-8 ofFig. 5 and showing one pan riser cap in end elevation and another in transverse section.

Fig. 9 is a fragmentary vertical sectional View taken on the line 9-,9of Fig. 5.

Fig. y10 is a'plan View of one of the re-boiler sections of our fractionating tower.

Fig. l11 is a vertical sectional view taken on the line 11-11 of Fig. 10.

n Fig. 12l is an enlarged fragmentary View of the left hand portion of Fig. 11.

' Fig. 13 is a vertical sectional Viewv of a novel ycentrifuge which is associated with the:

vaporizer of the refining apparatus shownin Fig. 1.

Fig. 14 is a horizontal sectional View taken .on the line 14-14 of Fig. 13.

apparatus for refining petroleum shown in Fig. 1 isa continuous pipe still process. This processhas a pressure pump 10 which draws crude petroleum from the crude storage tank 11 and pumps it through a pipe 12 to the pri- `mary heatV exchangers 13 from which it returns through a pipe 14 to thev secondary heat exchanger-s 15, from which it is led by a pipe 16 to a water separator 17, from which a pipe 18 ,conducts the crude oil to the pipe still 25. A gas or oil burner'26 provides fire to heat the stillpipes 28, through which the crude oil-circulates vand from which the oil is conducted through a pipe 30 at a tem,- perature of about 500 F., when treating a certain grade of oil chosen as an example, to a vaporizer 31. In the vaporizer 31 the hydrocarbons with boiling points below 500o F. separate out from the-residuurn in the Vform of vapor-s. The residuum is still very hotl and is conducted from the, bottom of the vaporizer31-.through the pipe 32 to the secondary heat exchangersv 15, where it heats the charging crude and is cooled thereby, then passing on through a pipe 33 to a pipe 34 which leads to airesiduum storage (not shown).

The mixture of vapors separated from the residuum, which are condensable at diiferent temperatures, pass from the vaporizer 31 through a vapor line 35 to a centrifuge 36.

loo

In this centrifuge entrained particles of liquid are removed from the vapor in they manner to be ldescribed later, and are returned to the vaporizer 31 through a pipe`37. '.lhevapor passes from the centrifuge 36 through a vapor lin-e 38 which connects with a lower fractionating unit 40 of the fractionating tower generally designated as 41.

The fractionating tower 41 in the embodiment shown has a Vertical shell formed by stacking a number of shell sections of the lsame cross section one upon the other. These shell sections are of two kinds, viz. condenser sections and re-boiler sections, each of the, former having one of `the latter disposed immediately beneath it and in communication therewith to form aA fractionating unit. Stacked upon the bottom fractonating unit 4() and extending vertically upward therefrom are fractionating units 52, 53, 54, 55, 56 and 57, all Vof which are identical in construction. Y The bottom fractionating unit 40, as illustrated in Figs. 2, 3 and 4, is composedofl a rvapor' vestibule condensing section 60 and a tower base re-boiler section 61.

The section 60 has a shell 62 of rectangular horizontal section, which is open at the upper tom of the'pipe and lower ends where attaching flanges and 66 respectively are formed uponthe shell 62. i A vapor inlet opening 67 is formed in the medial portion of a wall 68 of the shell 62 and the lower end of the vapor line 38 is secured againstthe wall ,68 by a flange 69 so that the vapor. line 38 communicates through th-e hole 67 with a vestibule chamber 70 provided in the middle portion. of the section 60. Fitted into th-e shell 62 just above the charnf ber 70 and welded to the shell is ay vapor distributor plate 72. This plate is provided with vapor distributing holes7 3 of an aggregate cross section equal to that ot the vapor inlet opening 67, andruniformly distributed over thesurface of. the plate 72.

A Icondensing panA has a floor plate 76 which is formed to tit the inside of the shell 62 and is welded therein in horizontal position inedially between the distributor plate 72 and the upper end of the section 60.

Referring to Figs. 4, 5, 8 and 9 for a detailed description of the pan 75, six parallel vapor riser openings 77are formed in the pan floor 76 and have walls7 8 rising upwardly along their edges to a uniform height.

A cap rests down over each riser openig77 outside the walls 78 upon the floor 76. Each cap 80 has a ceiling 81, side plates 82 bent downwardly therefrom, and end plates 83 closing the end openings. A cavity thus formed in tie cap 80 which opens at the lower edge of the side and end Valls 82 and 83. Spacing studs formed on the outside oithe1walls78 space the cap 80 a distance from these walls. Notches 91 are formed in the lower edges oi cap side and end walls 82-and 83, the apeXes of which are all on a given level. An angle iron 92 is welded to the outer face of cap walls 82 and 83 so as theicondensing pan 75 is provided with an inletor condensate discharge pipei94 andan outlet or condensate collector pipe 95 which are projected hrough holes iorn'ied in the walls of the shell 62 and wel-ded to these walls so that these two pipes are disposed parallel to and a small distance from the floor 76 at opposite ends ot' the yparallel riser opening caps 80. Holes 96 are formedalong the bot- 95 to allow liquid to pass thereinfrom the pan 75. j

Referring to Figs. 6, 7 and 9, the inlet and outlet pipes 94 and 95 project outwardly at one end bevondl the wall of the'shell. and

- are threaded to receive a `cap 97 and ajoint flange 98 respectively. Attached to the iiange 98 is au adjustable weir 99 having a housing 100and a rotor 101 having a weir opening 102 formed therein. The rotor 101 is rotatably seated `in thehousing. 160 so .that

liquid may yflow through the valve99 only by passing through the Weir opening 102. The rotor 101 may be rotated manually to control the elevation or' the weir opening 1021l and, hence, the level which the liquid mustattain in the pipe y95 before it will iiow v through the opening 102 by. gravity.- vThe 'novel features of this adjustable weir are fully'shown, describedy and claimed in our United States Letters Patent issued March8, 1927, No. 1,626,164, andv reference may be had to that thereon. 'j

The other end of the outlet pipe 95 is closed by a welded head 105, as shown in Figs. 6 and 9, and theother end of the inlet pipe 94 is closed by a welded head 106. Disposed through a hole in the head 106 and welded to the head so that it projects centrally into the inlet pipe 94 is a reflux-inlet pipe 107. ln Figs. 6 and 9 openings 110 are shown provided in the inlet pipe 94 along its top side and openings 111 are provided in the pipe 107` toone lside of the top side thereof so as to be out ofregistry with the holes 110. The purpose oi providing the holes 110 Aand the holes 111 out of alignment with each other' will be described later.

rThecor'idensingpan 7 5 with the inlet and outlet condensate pip- es 94 and 95 and the reflui; inlet pipe 107 comprises a condensing pan assembly 112. y

identical in structure and manner of mounting with the assembly 112, and mountedone above the other in the shell 62 between the lower end thereof and the medial vvestibule chamber 70 are condensing pan assemblies 115 and 116. Y

As indicated by dotted lines in Fig.f6, a pipe joint 'flange 120 is screwed uponl each of the condensate dischargepipes 94 of the pan assemblies 115 and ,116 and as shown in Fig. 2 the flanges 120 have gas trap elbows patent for further information- 121 and 122 joined thereto by end flanges 123 thereof.

flanges connects adjustable Weir housing 100 with the elbow 121 which communicates with the condensate inlet pipe 94 of the pan assembly 115. The condensateoutlet pipe` 95 of thepan assembly 115 has an adjustable weir 126 which is connected by a pipe 127 to the elbow 122 which communicates with the condensate inlet pipe 94 of the pan assembly 116. The outlet pipe 95 of the pan assembly 116 has a weir valve 128.

rlhe re-boiler section 61 has a shell 130 of identical cross section with the she-ll 62 and is disposed beneaththe shellv 62 in alignment and in contact with it. A flange 131 provided at the .upper end. of the shell is suitably secured to the flange 66 to form a gas-tightjoint between the shells 130and 62.. A flange 132 provided at the lower end. of the shell 130 is secured` to a base plate 133. A

,into a circuitouspassageway beginning and ending at the corners 140 and 141 respectively of the shell 130.

Opening into the shell lat its corner 140, as shown ink F ig. 10, is an inlet pipe 142 and opening from the shell 130 at its corner 141is an outlet pipe 145.

The inlet pipe 142 is connected through a gas trap elbow 146 and a standard 90o elbow 147 is Connected to the adjustable weir 128.

Tubes 149 pass through holes in the ends 138 and 139, as shown in Figs. 11 and 12, so as to form a dry heating element 150 in each of the aisles 151 formed by the baffle walls 137. These tubes 149 are rolled into a gas-tight lit in the shell ends 138 and 139, and project outwardly a short distance therefrom, wherethey pass into and are rolled to fit tightly holes provided in inlet and outlet header boxesY 155 and 156. These header boxes 155and 156 have face plates 157 secured on the outer ends thereof which may be removed to provide access to the tubes 149 for cleaning. An inlet pipe 160 is provided in the header box 155 and an outlet pipe 161 is provided in the box 156.

, A collar 165, as shown in Fig. 12, is provided in the shell end 138 opposite each of the aisles 151 and just above the floor 135. A perforated steam outlet pipe 166 passes through the collar and extends into the chamber 136 almost to the opposite( end wall 139. The inner end of each pipe has a cap 167 and the outer end has a steam valve 168 which connects througha nipple 169 to a steam manifold 170.

description of the unit'52 will suflice for all of these unitsv which are stacked consecutively upon each other as` shown in Fig. 1, above the unit 40.

' The fractionating unit 52, as shown in Fig. 4, comprises a condensing section and a re-boiler section 181. The re-boiler section 181 is identical to the re-boiler section 61 with the pan assembly 112 and-mounted, as shown inv Fig. 4, in the same manner', one below the other. j

As shown in Figs. 3 and 4, the pan assemblies 191 to 196 have outlet overflow adjustable weirs 201 to 206 respectively. The pan assemblies 192 to 196 have inlet gas trap elbows 212 to 216 respectively.

A pipe 222 connects the overflow weir 201 to the inlet elbow'212. n Similarly, the overflow weirs 202 to 205 are connected by pipes 223 to 226 respectively to inlet elbows 213 to 216 respectively.

The condensate inlet pipe 9401i the upper pan assembly 191 has a cap 230 similar to the is secured tothe lower flange 66 ofthe condensing section 180to form a gas-tight joint between these sections. y

ln a similar manner all pairs of'adjacent ends of the condensing and re-boiler sections of the fractionating units stacked upon each other above the unit 52 are joined together by flanges to form gas-tight joints theref between.

Y Resting upon the upper end of the top fractionating unit 57 is a tower cap 200. A flange 207 formed upon the cap 200 is secured to the upper flange 65 of the unit 57 and `forms a gas-tight union between the cap 200 and the unit 57.

Referring again to Fig. 1, a vapor line 208 is provided to lead from the top of the tower cap 200 to a gasoline condenser 209. A con- The fractionating units 52, 53, 54, 55, 56V and 57 being identical in structure, a detailed densate rundown line 209a leads from the bottom of the condenser 209 to a storage tank A boiler 211 generates steam which is conducted througha steam pipe 217 to each of the re-boiler steam manifolds 170. Likewise, a steam vlin-e 218 leads from the pipe 217 tothe vaporizer 31 which, as diagrammatically illustrated, is the novel vaporizer shown, described and claimed in our United States Letters` Patent, issued October 11,1927, No. 1,644,937, to which reference may be had if further information regarding it is desired.

It is desirable that the temperature of the re-boilers be controlled over quitea large range. Means are therefore provided for supplying a heat exchanging medium to the header boxes 155 of the various'fractionating unitre-boilers and running the medium away from the header boxes 156, thus causing a flow of the medium through the tubes 149. The intake of a residuum pumpA 220 is controlledr by valves 221: and 221a which communicate respectively wi lh the hot residuum line 32 a d with a line 223a leading to the crude oil storage tank 11. The adjustment ofthe valves 221 and 221a determinesA whether the heat exchanging medium drawn into the pump 220 will be het .residuuim cool crude oil or a mixture oit .residuum and crude. From the pump 220 an outlet pipe 225a communicates with a kstandpipe'generally desigsshowir in Fig. 3, this pipe 226m is builtup. Starting/at the bottom, the partsas far asfragmentarily shown, comprise a T fitting 2303, a shut-oli valve 231, a pipe 232i, a tourway Fitting 233, a valve 234, a pipe 235, a fourway fitting 236 and a 'valve 237.

The T fitting 230a communicates through. a pipe 246, a'regulating valve 241 andan Vel bow 242 with the inlet residuum header box an elbow 300 with the outlet residuum headerV box 310 of the re-bo'iler section 311 of the upnicates lon 155 ot thel lowermost re-boiler 61.Y The tour'- the right hand side through a pipeV 260, an

elbow 261, and a valve 262'with the inlet header box 263 of the re-boiler 264 of the tractionating unit 53. i'

vThe fitting 236 communicates on the left hand side through a pipe 270, anelbow 271,y

a pipe 272, an elbow 273, a pipe 274, a valve 275`and a T iitting 276 withthe residuum outlet header boX'27'7 of the re-boil'er section181. A built-up residuum return'line 280 has a pipe 281 which leads to a residuum storage tank (not shown) and upon the upper end of which is assembled in the following order, a T iittingi282,ia pipe 283, a T fitting 284 and a pipe 285 which'is shown in Figs. 2 and 3 asvbroken oil.' In the'portion of the fractionatingv tower which is shown as broken away in Fig. 3 the pipe 285 has a T fitting secured thereto andabove this are Joined successively a pipe and a T iitting` for. each of the tractionating units 54, 55, 56 and`57', the uppermost of these being a pipe 290 and a T fitting 291, the upper end of which issealed'by a plate 292; l

rllhe T fitting `282 connects through a valve 295 and an elbow 296 with 'the T fitting 256.

The Tiitting 284 connects through a Valve 297 and an elbow 298 with the T fitting 276. The 'l' iitting 291 connects through a valve 299 andY permost tractionating unit 57.

Asshown inFig. 4, the outlet pipe 145 of the re-boiler section 181 connectsto the lower end of a verticalv pipe: 320 which rises to a level slightly lower than the top of the battleV condensate run-down pipe 325. `In the same manner condensate run-down lines.324,v326`, 327. 328, 329 and 330 are connected-respective# .ly to the re-boiler sections-of the otherfractionatingunits 40, 53, 54, 55, 56 and 57.

As shown in Fig. 1, the-run-down linesf'324, 325, 326, 327 328, 329 and 330 pass through the primary heat'exchangers 13 and lead respectively toI condensate storage tanks 334, 335, 336, 337, 33s, 33eme 340. Y

As illustrated in section in Fig. 15, a-gas pocketpreventer 344 in the form of a small cylindrical condenser 345is disposedv'erti' cally' abovethe horizontal pipe`321 and has a neck pipe 346 which connects the two.

vThe condenser is of the standard` cylindrical 'torni and has `upper and-'lo-werfloors348` and 349 forming upper and lower condens` ing chamhers 350 and 351 and a medial-water chamber 352 through which pipes 353 pass, having their ends rolledintosuitableholes in the floors 348 `and 349"communicatingbe` tween chambers 350 and 351. Inlet and ut let water pipes 355 and356 connect with 'the water chamber 352 and are provided with water vcirculating ineens (notshown) which maintain the` pipes 353 and1 the ,chambers 350 and-351 at a. relatively'low temperature: A T fitting 357 communicates through a` nipple 358 with the chamber 35() and through nipples360'y and 361 with check valve 362 and a hand valve 363 respectively. Thecheck valve 362 .permitsy atmosphere to fiow into the chamber 350, Vlmtprevents `an outward iiow therefrom. The hand valve 363 may be opened to allow gas inthe chamber350-'to escape 'to the atmosphere.

As shown in Figs 1, 2,5and6`,each'of the reflux inlet pipesr 107 has a viiowregulating valve 37() which connects to-anipple371 pro- `iecting from al refluxmanitold`f372-` Eachof the fraction'atingunits hasa'iseparavtemanifold1372`which'is provided (as that shown inf 1 for theunit 57 with a supply pipe 375 which' leads to. a pressure pumpv 37 6l which'has an inlet manifold' 377through which it may draw condensate Vfrom any' ofthe ltanks 210 or 334 tof340-inclusive,and supply this for; use as a reflux to 'a particular manifold '372.

The centrifuge 36,A as shown in'Figsf. 13 and-14. has shell 380 of inverted conicalV forni `and has atangential vapor inleti38'1 provided at the upper end 'thereof anda? ver-V tical central vapor outlet 1pipe 383 projecting downwardly through the Vcenter thereolf to within afshort vdistancelo'i the bottoni, from which the liquiddrain pipe 37 leads through aga-s trap'385, back tothe vaperizer 31. VInf the present use' 4of the centrifuge 36 a-sep-aration ot entraine'd liquid particlesztrom the vaporleaving thefvapori'zer 3-1 is effected-by thev rapid rotationofthe vapors in the centriiirge-36. Theseparated liquid drains back I soA intothe vaporizer 3l thro-ugh the pipe 37 and the gas trap 385.

on by the apparatus illustrated in Fig. 1 is a continuous process. lvVhen the process is started, vapor is supplied as described i' through the vaporline 38 to the lowermost fractionating unit 40 of the fractionating tower 41.V The reiiux valves 3'10 are opened, each ofthe pumps 376 is connected 'through its manifold 377 with one of thecondensate storage tanks, and the pumps 376 are started. This supplies the desired grade of condensate as a reflux to each of the refiux manifolds 3.72, from'which it passes through the valves- 370into the VVreflux inlet pipes 107 and,`passing through the holes 111, fills the condensate inlet pipes 94, overflows through the holes 110 and fills eachr condensing pan in the whole towerto a level predetermined by the setting of the rotors 101 of each of the level controlling Weir valves. The maximum level thus attainable in anyof the condensing pans is vslightly below the top of the riser opening walls 7 8 so that under no circumstances may liquid in a condensing pan ovcrflowthrough the riserv openings 77. The minimum level attainableby control of the weir valve is located `slightly above the shelf flange 93.

Thus, after theV operation of the tower is once started and the condensing pans iilled with refiux totheir minimum level, vapor passing from below any given pan to the space above if it must pass up through the riser openings 77 into the cavity 84 of the caps 80, downwardly between the riser walls 7 8 and the cap walls 82 and 83, out through the notches 91 underneath the shelf 93 and upwardly atrthe shelfs "1 outer ed ge Ythrough a layer of liquid reflux.

VIn entering the fractionating tower 41, the vapor mixtureY passes into the chamber of the fractionating unit 40 and flows upwardly therefrom through the holes 73 in the distributor plate 72 andis uniformly distributed over the space 390 above the plate `72.` From the space 390 the-vapor passes up through thev condensing panv 75,v as vabove described. A few of the least volatile V1constituent vapors areL thereby condensed from the mixture due @to a slight'drop in temperature in its passage through the reflux in the pan 7 5. VYAs this condensation continues in the pan 7 5 the condensate accumulates and raises the level of liquid inthe pan so that it overflows through the 'Weir valve 100, passes'V downthevpipe 125 Ythrough the gas trap elbow 121 and into the fand the gasrtrap elbow 122 into the inlet pipe 94 of the condensing pan1l6. Y The level of liquidbeing thus raised `in the panV 116,

an overflow therefrom passes through the.V

weir valve 128, through the elbows 147 and.

146 and the inlet 142 into the re-boiler- 61. Here the mixture of reflux and condensate accumulates until the level is reached, Ywhere Vthe liquid will flow frcinV the vertical pipe 320 along the horizontal pipe 321fand downrthe condensate run-down pipe .324 to the storage tank 334.

The portion of the vapor 'mixture which is not condensed in the pan 75 passes from the space` 187 thereabove,` up through openings 186, in the bafie' walls 185 in the reboiler 181, to thespace 188., and from there, it passes up successively through the condensr ing pans 1,96 to 191 inclusive in the condens@ ing section 180. In each of these pans a portion of the less volatile of the remaining I vapors in the mixture is condensedby being i slightly cooled in passing through theliquid contained in the' pan. As the level of liquid rises in each pan due to an accumulation of the condensate, the mixture of `reflux. and condensate overflows therefrom. This overflow from the pan 191 passes through rthe weir 201, the pipe 222 and the elbow 212 into the inlet pipe 94 of the pan 192. Traversing the length of the pan 192and thoroughlyV mixing with the liquid therein,this overflow from the pan 191 passes ofi" with theover- `flow from the pan 192. In the same manner the overflow kfrom thepan 192 passes down to .the pan 193, and the overflow vfrom `the pan 193 passes to the pan 194, and so on, until the accumulated overflow from all the con? densing pans 191 to 196 inclusive is conveyed through the weir 206, the elbows 232 and 231, andthe inlet 142, into the re-boiler 181. kThe liquid collects in the re-boiler 181 untilit reaches the level from which it` overflows down the run-down *pipel 325 to the storage tank v335. j

The gas pocket preventer 344 Ais provided to condense any vapor which may form in anyof the horizontalpipes 321. 'If vapor were allowed to collect and form a pocket'in a pipe321, this would `stop theV passage of condensate into the run-down line connected thereto and, cause thecondensate in the reboiler, from which itis the outlet, to over flow into thecondensing section below.- The check valves 362 are provided to permit access of the ratmosphere toeach pipe321 to prevent sufficient vacuum being kformed therein to start Va siphoning action from any re-boiler down its run-down line. `The handV valves occurs, no great inconvenience is occasioned by the necessityY of manually relieving it.V

miV

, The portion of the vapor mixture which l,

units 53, 54, 55, 56 and57. In each of these units the temperature is a certain number of degrees lower than in the next unit below. Thus, vapors of certain liquefying temperatures that will pass through the lower fractionating units, due to the higher temperatures, will upon reaching the first fractionating unit having a temperature below their liquefying temperature condense and separate out from the vapor mixture as a condensate.

As these condens-etes collect inthe initial charge of reflux in the. condensing pans, the flow of reflux into the various condensing pans is cidade-wnV by the valves t7()` so that theamount of reflux introduced intoeach pan during the normal operation of .the tower 41 is very small in proportion to thecondensate 'formed in thatV pan. The effect of the introduction of reflux is well known in the art and `varies with the gravity Vand boiling point of thereflux. .Specialattentio-n may be directed, however, to our novel means of thoroughly mixing the reflux in each` panA condensate inlet pipe 94 with the condensate flowing thereinto from the higher pans in that fractionatingzunit. This equal distribution is highly important to ythe uniform treatment of allportions offthe .condensate and reflux mixture as it flows through each pan and uniformity in the product depends largely upon this uniformity of action upon all parts of the condensate flowing through each of the pans.

. The general purpose of the condensing sections, therefore, is to fractionally condense in a .succession of cooling stages the vapors of successively lower liquefying temperatures contained in the vapor mixture entering the tower. "This condensation successively of certain groups of vapors fromthe vapor mixture, each of which groups has lower lique- .fying temperatures than the other vapors remaining in the vapor mixture, is not ideally attainable by control of the temperature ot the pans of condensate alone. rThis is due to absorption by the condensate of some of the vapors whichnormally liquefy only -at a lower temperature than that of the condensate. The vapors thus absorbed in a given condensing section which are lighter than desired in the product from that section must be driven 0E. This is accomplished by heating the condensate to boiling temperature in the reboiler section immediately below each condensing section by the circulation ot residuum through the pipes 149. Driven oil by the boiling of the condensate, these lighter vapors again pass up through the condensing section in which they were lirst absorbed, and whileA a small part of them is re-absorbed a large proportion escapes on up to the next higher fractionating unit and continues on up in this manner' until it isfcondensed in the unit in the product of which it belongs.V The residirun is acconiplishedY by bulk of the condensate which passesinto each re-boiler consists of thefproduct desired to be tractionally condensed in thatunit. Some of this prod-uct is vaporired in-A the boiling and .driven offy with the lighter absorbed vapers, but this product is all re-condensedin the condensing section above and returned to the re-boiler. The condensate enters the reboiler at'the corner 140, as shownfin Fig. 10,

and ows serially through the five ` aisles 15,1

The temperatures of the fractionating .units progressively decrease from the bottom to the top of the tower. This reduction in temperature is controlled inthe condensing pans-by the temperature and grade ot reflux admitted and by the depth of liquid maintained in each an. ln there-boilers the temperature is controlled by the amount of hot residuum allowed to flow throughthe heat exchange pipes 149 and by the introduction of a greater or less amount of live steam through the perforated Apipes 166, shown in F igs.'10, `11 and 12. Y The piping described as connectingthe supply residuuml pipe 22GandV the return residuum pipe 280 with the ire-boilers is arranged tol provide for passing the residuum from 4the pipe226a through the re-boilers either in parallel or in series to the return g pipe `280. :This isf-a great advantage in that certain cr'udes may be suitably refined inour fractionating tower when the temperatures of the re-boilers decrease progressively from the bottoni re-boiler tothe top re-boiler, Idue' n to the progressive cooling of residuumpassed serially through the re-boilers one atterthe other, from the bottomunit on up to the rtop unit where it is discharged to the return line.

As showny in IFig. 3, the series flow Tof A K cl sing the valves 231, 234, 237 and so forth on up to the topmost vvalve (not shown) ot the residuum supply pipev 226, which topmost valve is always keptclosed during normal operation.

Also the valves 295, 297 and all similar valves communicating between .the` residuum return line 280 and theire-boilers,l exceptingthentop# most valve 1299.. are closed. The valves 241, 247, 262, 255, 275 and all Vsimilar valves, on the fractionating units which "are vbroken away, are` opened. I J

` The yresiduum valve 221 is then opened and.V the pump 22() started.Y `Residuum 4jflows through the pipe 2258#` to the 'T ittin`g230a and through the pipe 24()1 the valve. 241 and the elbow 242 to the intake header box 155 of the re-bo-iler 61. The residuum flows through the tubes 149 of the re-boiler 61 to theoutlet header-156,'from which it passes through the T itting 256, the valve 255, the

pipe 254, the elbow v253, the pipe 252, the elf bow 251, the pipe 250, the litting 233, vthe pipe 245, the elbow 246 and the valve 247 into the inlet header 248 of there-boiler 181. The residuum Hows through the tubes 149 of the re-boiler 181 to the outlet header 249 and thence through the T fitting 276, the valve Y `2175, the pipe 274,-the elbow'273, the pipe 272, the yelbow 271, the pipe270, the fitting 236,-the pipe 260, the elbow 261 and the valve 262 to the header box 263. From here the residuum passes through the re-boiler 264 andfrom there serially throughthe upper re-boilers in the same manner as it has just 'been described as passing through the rel boilers 61,.V 181 andl 264. After Vflowing through the re-boiler 311 of the vuppermost fractionating unit 57, the residuum passes intov'the outletl header box 310 and is con veyed from this through the fitting 300, and

' the valve 299 Ato the top Vfitting 291 of the fuum storage pipe 34.-

residuum return line 280. l cooled residuum passes through the line 280 to the pipe 281, which empties into the resid- Y When itis possible to route the residuum thus in series through the re-boilers from the bottom to the top of the tower, a maximum eiiiciency in the extraction of the heat from the hot residuum is accomplished. This is a great advantage in that only va small quantity of residuum need be diverted from `the secondary crude oil heat exchangers 15 `for'heating the re-boilers in the tower. How'- ever, the temperature Yofeach successive re- Vboiler through which the residuum flows in series is dependent upon the temperature to which the residuum has been reduced inthe re-boilers previously passed through. rVhen there-boiler temperatures thus at- Y. tained are not suitable for the proper fractopmost of these valves 299 which merely re- Y. 50- i i mains open; Y Y f,

Thel hot residuum then passes up the supply pipe 226Tand-outthrough the pipes 240,

v245, 260 and similar pipes for Athe re-boilers,

not `shown in detail. These pipes connect respectively through the valves 241;, 247 2.627, et

From `here the cetera, with the residuum intake headers 155,

248, 263, et cetera. From the header 155 the residuum l'lows through the 11e-boiler 61 and out from the outlet header 156, through the fittings 256 and 296', and the valve 295, to the residuum return line 280. From the header 248 residuum passes through the Vre-boiler 181, the header 249, theflittings 27 6 and 298,

and the valve 297, to the return residuum line 280. In the same manner Vresiduum passes from the supply line 226l in parallel through all the re-boilers tothe return line 280.

Intheparallelroutingof residuum through Y the re-boilers the temperature ofeach reboiler is controlled' by thel'amount of resi duum allowed to pass through the re-boiler.- Means for this control are' provided in the valves 241,247,262, et cetera.

In case a large volume ofV hot residuum were desired to be passed through two-orv more of the lower re-boilers, thesevmight be connected together inseries and the re-boilers thereabove in parallels` It will thus be seen that we have produced i a single fractionating tower by whichia mixture of hydrocarbon. vapors may be fractionally condensed into several commercial products, each comprising'a certain adjacent group of thehydrocarbons contained in the l vapor mixture. This result can only be accomplishedbyl our exact temperature control means. u

Another very importantresult of our accomplishing the complete fra ctionating process in a single tower, combined with our novel residuum circuitwhich utilizes the heat of the hot residuum to almost 100'per centeliiciency, is thejmarked economy of operatinga relining apparatus in which our fractionating tower is used. In our operation of such a plant, the A L Y iuel consumed has beenas low as 1. (5 per cent of the crude treated and hasaveraged under 2 per cent over a period of two months opera.

tion vhandling various grades of crude. oil.

VThe very best performance previously 'recorded by the largest and most Vprogressive oil companies in relinery practice is a consumpl tion of fuel equal to 2.25 per cent of the oil treated. i

In addition to this revolutionary Veconomy of operation of our Viractionating tower is the accuracy of control of theA 'deplilegmating action in the various ractionating units which permits cuts tobemade from the va-V por mixture, the initialboiling point of each il of which is higher than the end point for the next lighter cut. This control eliminates the cost of redlstllhng cuts having wrong yinitial or end boiling points Vwhich, .as wellVV vknown, has been heretoiore'an almost comkmon Vpractice in, thepetroleum'refining in'- dustry. Y

l/Vhat we claim is:

l V.1. In a dephlegmator the combination of: Y walls formingfa vertical closed chamber;

ilo

means for passing a vapor mixture into the bottom of said chamber; means for conducting a vapor mixture from the top of said chamber; floor plates secured to said walls to` form a series of dephlegmating pans disposed one over the other; walls forming risersin said floor plates; caps disposed over the upper ends ot said risers so that the mouths thereof are disposed on a level between the top from said lowermost pan.

2. In a fractionating tower, the combination of: a plurality of units placed one above stages, each of said units comprising a condensing section and a re-boilng section disposed immediately under said condensing section, each of said condensing sections coinprising a series of pans having walled riser openings therein and caps placed over said riser openings and adapted to deflect vapors rising through said openings downwardly into said pans, and each of said re-boiling sections comprising an open boiler having walled riser openings therein; means :tork conducting condensate from the lowermost pan of each condensing section to its re-boilers; means for conducting condensate from each of the other pans tothe one immediately beneath it; and means for determining the level above which condensate is drawn from each of the pans.

3. In a fractionating tower, the combination of: a plurality of units placed one above the other providing a series of ractionating stages, each of said units comprising a condensing section and a reboiling section disposed immediately under said condensing section, each of said condensing sections comprising a series of pans having walled riser openings therein and caps placed over said riser openings and adapted to deflect vapors rising through said openings downwardly into said pans, and each of said re-boiling sections comprising an open boiler having walled riser openings therein; a heat exchange element in each re-boiler section; la supply pipe for supplying hot residuum to said heat ex.

change elements; a return pipe; and means connecting said heat exchange elements with said supply and return pipes whereby the residuum may be run from the supply pipe through said heat exchange elements in parsupply pipe through said heat exchange elements in series to the return pipe. v

4. A combination asset forth in claim 3 in which each re-boiler section has a run-down i line; an inverted U-shaped pipe connecting of said levels from` which condensate isV drawn; and means for drawing condensate the other providing a series of fractionatingv allel relation to the return pipe or from the the upper end of 'each run-down line with theV lowerportion of itsrespective re-boiler; and meansfor condensing any Vapor POGket which mayforrn in said U-shaped pipe. Y

551Av combination as set forth in claim 2 inf which means are provided for-supplyingsteani directlyto the condensatein each reboiler section. Y p Y 6. A combination-as defined in claim 2 to which isA addedfineans for introducing a ref i 751 flux liquid into the condensateand thoroughly mixing the Vreilux with said condensate where the condensatel is discharged insaid pans. f i Y g '7, ln a fractionating tower, the combination ots: a plurality of units placed o-ne above the other providinga series of fractionating stages, each of said units comprising a con-f densing section and a re-boilingsection disposed immediately under said condensing; section, each of said `condensing sections Coin-LA prising'a series of pans having walled riser openings therein and' caps disposed over said riser openings adapted to deflect vapors rising through said openings downwardly into said pans, each of said re-boiling sections comprising an open boiler having walled riser openings therein, and a run-downl line; a pipe connecting the upper end of each run-down line with the lower portion of its respective re-boiler; a heat exchangeelement in each re-boiler section; a supply pipefor supplying hot residuum to said heat exchangefelements; a return pipe; a check valve provided to communicate between said irst mentioned pipe and the atmosphere; and means con? necting said heat exchange elements with said f supply and return pipes and adapted to run the residuum through said heat exchange elements in parallel relation tothe return pipe 1'0'5 or-A through said heat exchange elementsV in series tothe return pipe. Y y

'8.In a fractionating tower, the combination oie: a plurality of units placed one above the other providing series of fractionating' 110 stages, each of said units comprising a condensing section and a re-boiling section disposed immediately under said condensing section, each of said condensing sections come prising a series of pans having walled riser 115,

openings and caps disposed over said openings adapted to deliect vapors rising through said openings downwardly: into I said pans, cachot said re-boiling sections comprising 'an Y open boiler having walled riser` openings therein; a heat exchange element in each ref boiler section; Va supply pipe for supplying hot residuum to said heat exchange elements;

la return pipe; and means `for runningthe residuum from the supply pipe through said heat exchange elements in'parallel relation to the return pipe or through 'said heatV exchange elements in series to the return pipe.

. 9. A combination as setrforth in claim V8 including: a run-down line for each re-boiler section; a pipe connecting the upper end of Yeach run-down line with the lower portion of its respective boiler; and means for-con- (lensing vapor which may form in a, pocketV 5in said pipe connecting the run-down line With'its respective re-boiler. Y

' 10. A Combination as set forth in claim 8 in Whicheach re-boiler section has a rundown lineV and an inverted Ueshaped pipe m connecting each run-down line with its respecti-vefre-boiler.

11.'.A combination as setforth in claim 7 in which said? Vlirst mentioned pipe is U- shaped. f 153 12. A combination as set forth in yclaim 7 in which means is providedfor condensing vapor Which may form in a pocket insaid first mentioned pipe.- f

In testimony whereof, we have hereunto 205 set our hands at Los'Angeles, California, this 24th day of December, 1925.v

FRANK A.. MILLIFF.

JOHN A. MILLIFF.

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