US1657524A - Asshbtoe to doherty ileseabch comt - Google Patents

Description

Jan. 31, 1928. 1,657,524

H. w. CAMP PROCESS AND APPARATUS FOR TREATING HYDROCARBON OILS Filed Nov. 29. 1922 (Ml/1V6 (GIL ,By P60 5 i M W W [five/ram .Atmngy.

Patented Jan. 31, 1928.

'tllllll hll.) STATES PATENT OFFICE.

nrneM w. carer, or TTJ'LEeA, OKLAHOMA, Assronon 'ro DOI-IERIY RESEARCH COM- IPANY, or new "roan, n. 1%., a oonronnrron or DELAWARE.

rnoonss AND ArrAnarus non TREATING rrvnnocannon OILS.

Application area November 29, 1922. Serial No.60 1,086.

The present invention relates to a process and apparatus for treating hydrocarbon oils and, more particularly, to a process and apparatus for distilling higher boiling point hydrocarbons under pressure to obtain lower boiling point hydrocarbons.

In the pressure distillation and cracking of hydrocarbon oils, residues containing hy: drocarbons of high carbon content and ot sticky, viscous and tarry propertles are formed, together with some free carbon. These residues are formed principally ad]acent the heating surface and cling to and readily form deposits on any surface wlth which they come into contact. Owing tothe sticky, adhesive nature of the resldues their removal from the 'sui"liaces to which they cling is very ,diiiicult during distillation and upon continued heating they harden and cement the free carbon into ahard, dense, coke-like mass firmly adhering to the surface on which it formed. Pressure distillation is, therefore, largely limited to stills which have smooth heating surfaces and which a'ltord ready access for cleaning, as, for example, the common type of horizon tal, cylindrical still. "Stills of this type,

however, afford a minimum of heating surface andall of this surface is so positioned that carbon readily deposits upon it. These deposit-s rapidly bake to coke, thereby gravating the formation of troublesome coatings which interfere with the SlJ-lll operation.

An object of the present invention is to provide a still which affords a large heating area and a surtace on which there is little tendency for residues to settle and bake.

Another object of the invention is to provide a process of distilling hydrocarbon oils in which the residues are readily and effectively removed during distillation Ai -flirt ier object or the invention is to provide a still in which the heat transmitting walls are so arranged as not to recelve the falling residues or sett-lings.

A still further object of the invention is to provide a still and furnace therefor in which an ell'ective transfer 0t heat to the body of oil in the still and an accurate control oi the temperature are provided.

Another factor of pressure distillation having a bearing on the effectiveness ot the cracking treatment is the separation 01": the low boiling products {rein the heavier hydrocarhons in the still vapors and the rapid removal of the lower boiling vapors from the still while holding'baclr the heavier hydrocarbon products. It the low boiling products are permitted to return to the still, they absorb heat for their re evaporation and may, themselves, be further broken down into gaseous products and lost. If a large quantity of heavy hydrocarbons is permitted to pass with the lighter products from the still to the condenser, their subsequent separation involves considerable further expense.

Accordingly, a further object of the invention 1s to provide an apparatus in which the heavier products in the still vapors may so effectively separated from the lighter vapors and returned to the still.

A further object of the invention is to provide a process of distilling hydrocarbons under pressure in which the heavier constituents of the vapors of distillation are ett'echeated still bottom portion into which the heavier residues of distillation tend to set tle, of a scraping device for stills adapted to scrape adheringresidues from the still walls in such a manner as to permit them to readily settle away from the heated portion of the still, of a residue draw-oil means adapted to effectively clear the bottom portion of the still from settlings and of an improved charging and run-back arrangement for the condensed still vapors.

With these and other objects in view, the invention comprises the process and apparat-us described and set forth in the following specification and claims.

The various features of the invention are illustrated in the accompanying drawings, in which: i i

Fig. 1 is a side view, partly in section, of a distilling apparatus embodying a preterredform of the invention, and,

Fig. 2 is a cross section of a still forming a part of the apparatus of Fig. 1, taken on line 22 of Fig. 1.

In the present invention, the hydrocarbon oils tobe treated or distilled are heated in a vertical-still in such a manner that the lower or bottom portion of the oil is unheated. In the heated zone or portion of the still,v the still is entirely surroundediby the burning gases and hot products of combustion and the heat is transferred to the body of oil through are vertical walls; ofthe still. The inner surface' of the' still wall is inaintained i tendency for them to rapidly harden and.

are removedthrouglra.draw-off pipe. The heating; zone" or portionof the still is heated by a-furnac'e:inwhich'the burning gases and products of: combustion are caused to travel yinan upward,;helicah path. around the still walls, thereby: providing a long. path. of-

contact withthestillawalls and airetticient utilization or absorption of the heat. of. the furnace gases by the. still walls:

'Ilhevapors formed in the still. are collected in theaipper portion lot the stilliandt pass to adephlegmator or vapou towera In. this tower the vapors contact witha circulating. stream'sof cold: condensate which is cireu- 'latedi successively in: a circuit through the towerand: through: a coolingimeans, as, for example; a Water. cooledcoil. Theexcess of condensate'prodnced by thecondensation of a portion of the vapors is'ret1u'ned to-the -still, togeth'eri with supplyof fresh oil for treatmentt The vapor tower isprotected from uncontrolled: coolinggby means of suitable insulation: and! the chilling or condensingttemper-aturesin the. tower are controlled tor hold backxany-,desired portion of: the vaporssformedine thenstill: The condensate from the tower is returned tOrtllE; still by al pipe: separate: from t-hevapor: pipe therebyavoiding." any disturbance of: the: conditions established! in'the tower;

Referringimore particularly to :the: accompanying drawings, a body of oilt"10-to be treated is" contained: in a vertical cylindrical still 12 exten'dingthrough a furnaeel'tand projecting-.fbelow' the bottom :walll of; the fur? nace. The portion. of. thestill- Within: the furnace isv filled. with oil to a' levelsubstantially-leven with? the: top'of the furnace. and

the oil is heated through the vertical still:

wallsilti froinrthe;surrounding furnace gases abodyr of oill maintained under sufli-- cient pressure'stoi obtain the proper craclrin temperature: in the: still,. the vaporsbeing collected under. pressureim a vapor space 18 in the top portion of the stillandlwit-hdrawn' through a vap'o'r outletf pipe 20.

Aim adhering layer of: heavy hydrocarbon: residues tends 'to form on: the inner surface of the still wall 16, either through the con i tact of parti'clesiof heavy residues of distillation circulating'from the inner portion of the body of oil tothestill walls or, more probably, by being formed by cracking in contact with the hot walls of the still. This adhering layer. is removed by means of scraping blades QQzcarried in circular paths around the inner surface of the still walls on afra-me 24 rotating ona vertical shaft 26 arranged axially in the still. The scraper blades 22 are arranged substantially vertically,.or inclined slightly forwardly toward their upper ends, as, for example, about 5 from the vertical in order that the residues scraped from the still walls may fall freely from the blades and to increase the forces tending to free the scraped material from th e blades.

The blades are yieldingly pressed out wardly in such a manner as to force the outer cutting or scraping edges of the blades into intimate contact with the surface of the still walls while permittingthem to give inwardly uponstriking an inwardly extending projection of the still walls and to push outwardly into any irregularities in the still walls. For this purpose the blades are slidably mounted on individual arms 28extcndingz'radially outward from the shaft 26 and are individually forcedinto contact with the still wall by weighted levers 30 which are pivoted to-upright rods 32in such a position that the" outer ends of the levers bear against the blades by the gravity action of weights onthe inner ends of the levers. The blades are preferably mounted slidably on the end portions of the arms 28 by means of cross bolts or pins 34 passing through slots 36in the ends of thc arms. The vertical rods 82ers mounted on the outer portions of the arms 28 and are attached at their upper ends to: a supporting. spider 40 mounted onv the shaft 2.6. The outer ends of the spider frame 40 aresupp orted by guy wires l2 extending from the outer ends of the frame to arcollar d l clamped to the shaft 26 and diagonal braces 41-53 are connected between adjacent arms of" thespider. The shaft 26 is supported on the bottom of the still by means of a thrust bearing 46 carried on a suitable tripod or. bracket 48. The upper end of the shaft extends through a packing gland in the top of the still into a gear housing 50 where it is connected by suitable gears 52 andh?) with a'drive'shaft 54:;

The heavy residues gathered by the blades 22 or formed in the body of oil 10 settle downwardly through the body. of oil into a settling chamber 56 formed at the bottom below the furnace 14-. As this portion ofthe still is" unheated there is little or'no tendency for the settlings to harden on the from the sloping bottom and from which they may be withdrawn through an outflow pipe 60 and valve 62. As the settlings accumulating on the still bottom adhere to the bottom with considerable persi'stency they frequently remainv clinging to the still walls when the liquid is drawn out in a steady stream, as the flow may not be sufficient to sweep them free from the walls. The re sidual liquor is therefore drawn out intermittently in short, fast flowing spurts which shake the adhering substances from the still walls and bottom and sweep them into the outlet pipe. To insure the required flow during these outflow intervals, a pump 64 may be attached to the outlet pipe 60 to increase the rate of flow when necessary. The end of the shaft 26 is also preferably extended into the well 58 and provided with a helical or screw blade 66 which rotates with the shaft and stirs up the settlings in the well and prevents them from caking or packing to a solid mass during the period of accumulation. The bottom of the well or outlet 58 is closed by a removable plate 68 which may be removed when the still. is to be cleaned. The still bottom is also provided with separate manholes 70 and 71 for cleaning purposes. To avoid danger of fire by contact of the hot still residues with the atmosphere as they are released from the still, the outlet pipe 60 may be connected with a cooling coil, or mounted in the form of a coil, in a cooling box 72.

The portion of the still within the furnace 14: is heated throughout its surface by rapidly moving and uniformly distributed conibustion gases inv such a manner as to obtain a rapid. transfer of heat from the furnace to the interior of the still without excessive local temperature gradients or local ovcrheating. To this end the flames and hot products of combustion are caused to travel about the still in a helical path and in rapid movement over the outer surface of the still. The fuel is i gnited in an ignition chamber or Dutch oven 74 at one side of the furnace, a jet of fluid fuel from a burner nozzle 76 being used in the embodiment illustrated in the drawings. From the Dutch oven or ignition chamber 74 the burning fuel passes through a refractory grating '56 into a d1stributing chamber 78 formed in the lower part of the furnace by a horizontal perforated partition 89. The hot gases are CllS- tributed about the still by the partition 80 and, upon passing upwardly through the partition, flow upwardly through a helical flue 82 formed by a helical partition 84E extending inwardly from the furnace wall to the still walls. The rapid turning movement of the hot gases serves to continually luring new portions of the furnace gases into contact with the still walls thus insuring a rapid and uniform absorption of heat from the walls of the dephlegmator.

the gases. From the upper portion of the furnace the waste products of combustion are exhausted through an outlet flue 86 to a stack 88. Through the above arrangement of still and furnace, the greater partof the area of. the still is utilized for heating the oil and, through the rapid circulation of furnace gases over the outer surface of the still and the eiiicient scraping and stirring action on the inner surface of the still, a rapid uniform heating is obtained.

The vapors passing from the still. through the vapor line 20 enter a vapor tower or dephlegmator 9-0 at a short distance above the bottom of the tow r and pass upwardly through the tower alternately through central openings92 in annular plates 94 and annular openings 96 between plates 98 and In passing upward past the plates 94 and 98 the vapors come into intimate contact with bodies of condensate which are maintained on the plates by upwardly extending flanges 99. The vapors also directly contact with condensate trickling downwardly from plate to plate and are thereby cooled to a temperature at wl'iich the higher boiling constituents of the vapors are condensed and alosorbed into the body of cold circulating condensate. The vapors reaching the upper part of the tower are therefore enriched in the lighter constituents and deprived of the undesired heavier constituents; As referred to in detail hereinafter cold condensate is introduced into the tower in order to effect and control the condensation of the vapors therein. This condensate is preferably introduced into the tower at a short distance from the top so as to leave a few plates above its entrance on which any entrained particles of heavy condensates may be caught and removed from the vapors before the vapors leave the tower. From the top of the tower the purified vapors pass through an outlet pipe 100 and .apressure release valve 102 to a suitable condenser 1041.

The liquid condensate in its downward flow through the tower is heated by contact with the hot still vapors and gives up any vapors which it may have absorbed or condensed in the upper part of the tower. By a proper control of the temperature of the down flowing condensate, it reaches the bottom of the tower substantially free of the light products desired in the low boiling product and is con'iposed principally of constituents suitable for cracking in the still 12. From the bottom of the tower the condensate is drawn through an outlet .pipe 106, valve 108 and suction line 110 to a circulatinp; pump 112. The condensate is forced by the pump through a cooling coil 114 in a cooling boX 116 in which it is cooled to a temperature suitable for its admission to the upper portion of the tower 90. From the'icoo'ling coil theecoole'df condensate passesthrough a pipe 118 and: valve. 120 to the tower;90;.enterin'githe:to-wer belowagroup of: plates 121. im the upper part ofz ther tower. A- relief valve 122; is; insertedrbetween; the

suction pipe 1 "110 and: the: discharge pipe 1:18

cbvwhi'chi a: portion; of the cooled. liquid may be; returned to t the pump inlet: and: recirculateditlirouglnthe: cooling coil By means of" this. valve; in: connection; with the? valves- 108 and 120;.tl'rerate oii'ciroulation OfICO11-- densate through! the :tower and the, temperatures} within. the: tower may; be accurately controllech toiprovide' the proper'separation of the vapors. 'lioxaroid any disturbance-o1": this. control through uncontrolled: transm1s sion' ofi'heati through the walls oft the tower,

particularly. when: the tower: is subject: to wide variations 1n atmospheric conditions the outer'surface oi the-towers ls covered w1th= a layer of heat insulating material: 12 Variations, in. temperature through the cross SQOtlOHi oh the tower are: also. minimized oreliminated by this insulation;

Thecondensation ofLvapors'in the dephlegmatingtower may be controlled also by. meansofiacoolin'g'liquid which is circulated through: a: coil125iin: the tower: adjacent: the plates 121l The cooling liquid may. con':

sist or" the cold} incoming oil to be treated;

or" may be water. or other s-uitableliquid;

By: means of the cooling circuit of'conden sate and the coil 125 the'characterof vapors lcaving'thetop' of thedephlegmatingtowermay be controlled at' will.

The still' is preferably'operated as a batch still in a semicontinuous manner; that is,

aft'era quantity of the oil has been distilled oti"and=other portions of the oil 'withdrawn from the'bottom-of the still to remove car bon, tar and sludge, oil may be charged into' the still to maintain the stillik The oil may also "8 charged continri uously without danger of the oil level risingtoo high. The pump in oil is received through a supply pipe 126211101 forced by ineaiis-ofa-puinp 128through a-pipe 130 into 1 a reflux return pipe 182. When oil is circulated tliroughthe cooling. coil125" at the top o f the dephlegmator the pipe 126 will be connected with-said coil as will be readily (lO mating tower anda portionof-thishot condensate flows through the line 106 and through'a valve 13 1 into the=reflux line 132. A certain portion of the condensate which @59 is used for the cooling circuitin the tower of fthe heavierrfrom the lighter constituents;

1390f any suitable construction and proper level in the cooling circuit for the dephlegmating tower' ream-524 is introduccd'into the cooling circuit through 'the valve 108. The fresh incomingoil -from supply 1smixed with the condcnsaic pas.=:-.

is made between the pipes 118 and 106 by means ofa valve 138 and pipe 140 by which condensate from the cooling circuit may be introducedinto the reflux line 139 if desired.

Byusing the condensates ot the dcphlcg matingtower as a cooling medium a comparatively accurate fractionation of the cracked vapors may be carried on at the same time that thecooled condensate is used for controlling the temperatures of the condensates in-the dephlegmating tower. iVhcn for c:-:-. 2111113165 crude oil or fresh incoming oil is inserted into the dephlcgmating tower, this oil contains a mixture of light and hoary vapor fractions which disturb the cquilibrium' set up by the dephlegmating tower. The cooledcomlensatc however docs not contain the light vapors and acts only as a cooling medium without interfering with the vapor 1'1".Gt101121t1011.

The still is provided with a safety valve is so supported that access may be readily had to itscleaningplate 68 and man hole 70. To thisendthe-bottom of the still is supported, on afoundationor supporting structure 14-2 OfiOOllCl'OllG'Ol'. other suitable structural material and a tunnel 14-1 for placing a cart under the'outlot58 and a room for the pump 64: are provided'in this su 'iporting structurc.

Having described the invention, what I claim. and desire to secure by Letters Patent is:

1'. The process of dephlegmating oil vapors. in a dephlegmating zone which comprises circulating a cooling medium in a. closed. cycle through a cooling zone for said medium and in heat interchange with vapors inisaid dephlegmating zone and recirculating through the cooling zone a portion 01 the coldmcdium leaving said cooling zone.

2. A process oi controlling the tempera ture gradient in a dephlegmator, comprising introducing hot vapors from a still at a point near the bottom oi the dephlcgmator, introducing a chilled condensate into the dephlegmator at a point below the top thereof, withdrawingcondensate from the bottom of. the" dephlegmator and returning a portion thereof: to the de ihlcgmator after first ch lling the same, injecting the other portion of condensate into the still, reducing the how of the chilled condensate to tho dcphlcgmator by diverting a portion oi? the same into the still and mixing fresh hydrocarbons with the condensate flowing to the still.

3. A process of controlling the temperature gradient in a dcphlcgmator, comprising introducing hot vapors from a still at a poiiit near the bottom of the dephlegmator, introducing achillcd condensate into the dephlegniator at a point below the top thereof withdrawing condensate from the bottom ot the dephlegn'iator and returning a portion thereof to the dophleginator after first chilli the same, injecting the other portion condensate into the still, reducing the lion of the chilled condensate to the dephleg nnator by diverting a portion of the same into the still and further reducing the flow of chilled condensate to the dephlegmator by diverting a portion thereof into the stream of condensate flowing from the bottom the dephlegmator.

4:. ln. apparatus for distilling hydrocarhons a a dephlcginator, a vapor pipe leading from the still to the dephlegmator, means for withdrawing condensate from the bottom of the dephleginator and diverting one portion thereof to a cooler and another portion to the still, means for controlling the flow of the conden te to the still and cooler, means for returning the cooled condensate to the dophlegmator, and means for divet-ting some of the cooled condensate into the condensate lacing Withdrawn from the dephlegmator.

5. In amaaratus for distilling hydrocarbons, a still, a dephleginator, a vapor pipe loading from the still to the dephleginator, means for Withdrawing condensate from the bottom of the dephlegmator, and diverting one portion thereof to a cooler and another portion to the still, means for controlling the flow of the condensate to the still and coolor, means for returning the cooled condensate to the dephlegmator and means for di verting some of the cooled condensate away from the dephlegmator into the still.

6. The process of cracking hydrocarbon oils which comprises heatingoil in a still to produce vapors therefrom, passing said vapors to a dephlegmating zone to produce a reflux condensate, passing a stream of said reflux condensate through a cooling zone, forcing cooled condensate into the upper portion of said dephlegmating zone to flow therethrough in heat interchange with said vapors, circulating a portion of said cold condensate in a closed cycle through said cooling zone and diverting a portion of the cooled condensate being passed to the dephlegmating zone.

7 In apparatus for distilling hydrocarbons, a still, a dephlegmator, a vapor pipe leading from the still to the dephlegmator, means for Withdrawing condensate from the bottom of the dephlegmator, and diverting one portion thereof to a cooler and another portion to the still, means for controlling the .flow of the condensate to the still and cooler, means for returning the cooled condensate to the dephleginator and means for diverting some of the cooled condensate away from the dephlegmator into the still and means for injecting fresh hydrocarbon into the still along with the condensate inject-ed therein.

8. In an apparatus for treating petroleum oils, a still, a dephlegmator, means for conducting vapors from said still to said dephleginator, means for passing reflux condcnsate from said dephlegmator to said still, a cooler for liquids, means for passing a portion of the condensate produced in said dephlegnnator in a closed cycle through said cooler and said dephleginator to produce cooling of said vapors and means for passing a portion of the cooled condensate leaving said cooler back through said cooler 'WltllOtlt passing it through said dephlegmator.

9. The apparatus defined in claim 8 in which means independent of said last mentioned means is provided for decreasing the amount of cooled condensate passing from said cooler into said dephlegmator.

In testimony whereof I affix my signature.

HIRAM W. CAMP.

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