US1868395A - Distillation of tar - Google Patents

Description

July 19, 1932. s. P. MILLER DISTILLATION OF TAR Filed Feb. l5, 1928 2 Sheets-Sheet l xNvENToR Mm/ffm K t n WL/ BY 63,2%, w MMMQM ATTORNEYS July 19, 1932. s. P. MILLER 1,868,395

` DISTILLATION OF TAR Filed Feb. l5, 1928 2 Sheets-Sheet 2 l faZZefaf' /I/a z'n l Zora/fe Pzpe INVENTOR ATTORNEYS Patented .lul-ly 19, 1932 narran srATl-:s

PATENT OFFICE STUART PARMELEE KELLER, OF ENGLEWOOD, NEW JERSEY, ASSIGNOR TO THE IBAR- COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY DISTILLATION OF TAR Application filed February 15, 1928. Serial N0. 254,356.

This invention relates to improvementsl in Y the distillation of tar and the vproduction of pitches and oils therefrom and from coal distillation gases, and includes a new method of tar distillation and of pitch and oil production and improved apparatus therefor. More particularly the invention relates to the recovery of `pitch and oil products at coal-carbonization and distillation plants such asv 'l0 by-product coke ovens and gas retort-plants.

ln the ordinary operation of by-product coke ovens the gases produced'by the colring operation pass `trom the individual ovens through uptake pipesand goose-necks to a l5 collector main common 'to the ovens of the battery. The coke-oven gases Which leave Jthe ovens at temperatures from 600o to 700 C. or higher are cooled in the lcollector main and in condensers connected therewith to separate tar constituents therefrom. The separated coal tar is commonly shipped to tar-distillation plants Where it is subjected to distillation to produce pitches and various other products.

" Owing to the high temperature of the gases from the colte ovens, and particularly because of the large amount of heat carried thereby, the successful operation of the collector main in connection with these ovens has always 3u been a serious problem, The heat carried by the gases is sutlicient to distill many times as much tar as is produced from the gases. A

certain amount of heavy tar or pitch tends to separate in the collector main and, unless precautions are taken to prevent it, such tar or pitch is subjected tothe distilling effect of the fases at high temperature With the resulting' formation in the main of hard pitch which can in some cases be removed only by shutting down the plant and scraping or digging it out. lt is customary to flush the main With a mixture of tar and ammonia liquor or with ammonia liquor alone, but this practice does not always avoid the difficulty. ln fact, the use of water or ammonia liquor may aggravate the trouble in somecases because the pitches formed in the main are insoluble in water or ammonia liquor and hence are not lushed out unless a large amount of' liquor or of tar and liquor is employed. i

` The use of a large quantity of ammonia liquor in the collector main results in rapidly lowering the temperature of the gases. Thus, by spraying ammonia liquor into the collector main insufficient quantity to prevent accumulations of pitch therein, the temperature of the gases may be so reduced that a considerable proportion of the valuable oil constituents which are present in the gases is condensed and thrown down With the tar and may be recovered therefrom only by subsequent distillation.

The present invention provides an improved method and apparatus in which pitch and oil can be recovered directly and continuously from the coal distillation gases,

and in which tar islalso distilled continuously by the gases to produce pitch at the coal-carbonization plant, such as a. byproduct eoke-oven or gas retort plant. The invention includes improvements in the operation of the collector main of a coal distillation plant whereby advantage can be taken of the heat carried by the coal distillation gases to distill tar and oil and to separate volatile products therefrom so that the latter can be recovered independently of the pitch which then constitutes a separate product of the operation ;'and it includes also improvements in the treatment of the coal distillation gases for the direct recovery of merchantable pitch and oil products therefrom.

The present invention includes the separation from the hot gases of substantially all solid and tarry constituents, leaving only relatively clean oil vapors therein which upon condensation, yield clean oils adapted to be utilized in the trade Without further distillation or other treatment.

According to the present invention the hot coke-oven gases as they come from the coke ovens are utilized for the distillation of tar and the separation of vaporizable oils therefrom by passing the gases through the collector main and by maintaining therein and 9d circulating therethrough continuously a large and constantly changing body of tar to be distilled; and the still hot gases are then sul jected to a scrubbing treatment While still at a high temperature to remove suspended 1* .tar is effected to a greater or less civ-:tent sov that the more volatile constituents are sepa-l l5 the hotgases... The pitch. resulting from the distillation maybe withdrawn .from the mani.

and-:recirculated therethrough for yfurther distillation. 'The `extent vof the distillation eifected may be regulated and consequently the character .ofthe pitch produced can, be modified as desired toproduce salable pitch products. i, Y The river ot tar and pitch flowing continuously through the collectorvmain will be heated hy thehot gases and its temperpl^J c may be raised considerably. lart` etnie Lieat is employed, however, in vaporiaing oil constituents of the tar without corresponding increase in thetempcrature thereof so that the maximumtemperature of the tar and of Ithe resulting pitch may be considerably below that of the gases. .To avoid accumulation oi? 't that a hard pitch in the main it is importer p large volu'ne of tar or pitchbe circulated actively and continuously through the main,

particularlywhen the tar or pitch in the .main is )not eiiectively agitated.. The heat available in the gases is such astol insure vthe heatingof the ytar orpitch to a temperature at which vit is thinly fluid so thatit can be circulated easily. Moreover, .the hot tar or pitch readily dissolves any` deposits of solid hard pitch in the mainand accumulation thereof isr thus avoided.

, Indiscriminate cooling ofthe gases in the collector main is to be avoided, but it may be desirable to introduce a limited amount oit waterV or ammonia liquor, y for example, against the valves .in the uptalrepipes tor the purpose off cooling the gases to a predetermined and regula-tedl extent.. rlhe regulation of thecooling eiiectcan be accomplished morev vreadily with water orannnonia lliquor becauseof thehigher specific fandlatent heats ofwater as comparedtothoseof tarandoila' Cooling of the gases to a regulated extent" canv also `be accomplished by the introduction of oil withthe tar. Thus,a proportion otthe oilfrecovered from the-gases canV be returnedV to the collector inainand mingledy with the tar or. pitch therein. riChe distillation oi? this oil in a collector main`A will absorb @heat fromV of the .desiredr temperature therein.

rated therefrom and 'areicarried away with" Y the gases and thus perni-it the maintenance The distilling capacity of the gases from a single coke ovenbattery is greatly in e2;- cess of that required for the distillation oi the amount of tar which a single colre oven battery produces, even where the only contact between the gases and tar or pitch is surface contact or" the circulating stream of tar or pitch, without atomizing or spraying the tar or pitch into the gases. Consequently, to maintain the operation as hereinbeiore de- "scribed, it is ordinarily necessary to pro` vide an amount of tar very much in excess of that produced by the single battery which is sc operated. The tar employed maybe that produced by another coke oven battery or such as gas retort-s, vertical retorts and water-gas sets. Such tar may be mingled with tar 'from the battery or it may he introduced 'independently and circulated through the main for the purpose of producing pitches having diiierent characteristics from thosev derived from 'coke voven tar. lf tars from different sources are mingled and introduced tothe collectorinain for distillation in the manner described, composite pitches will be `produced,and vin this manner products having a, greater or smaller proportion of tree carbon than normal coke oven pitches can be prepared. Composite oils will also be obtained from subsequent treatment of the gases.'V f Y The hot gases dowing through the collectormain will be cooled partially by transier ci heat to the tar or pitch undergoing distillation, and the gases will be enriched in oil constituents derived from the distillation oit the tar or pitch. lThe gases will, however, leave the collector main still at rela-r tively high temperature, e. g., at tempera ture around 300 C. or 350"V C. or higher, and will carry in addition'to the oil vapors a certa-inproportion or pitch particles in the forni of fog, together with solid particles ot coal, colic, etc., which are carried over from the colre ovens.

Y ln the practice of the invention, it is not intended that the gases flowing through the collector main willbe radically KVcooled to a low ,temperature,` or that the maximum di still-ing eiflject oi the gases upon the tar or pitch circulating through the collector main will be employed. The collector ,mainV operation is intended rather to insure. that the gases passing therethrough are maintained at a high tempera-ture and that the collector main itself is kept free from accumulations of hard pitch. More vor less distillation of the circulating river ot tar or pitch will, however, be obtained, and the Acirculating tar or pitch will be suihciently hot and thinly iluid to promote eiective distillation by surface con tact with the hot gases, with 1esulting enrichnient of the gasesy in oil vapors. The hot gases leaving Vthe collector main will theremay be tar derived, from other sources still contaminated with suspended pitch particles,` and containing` a large part of the oilsin vapor form, are subjected to a scrubbing treatment at a high temperature, e. g., with hot tar or pitch, to separate suspended pitch and solidparticles therefrom While still leaving a large part of the oils in vapor'form. Such treatment at a high temperature recovers the pitch content of the gases in the form Vof Vmerchantable pitch of regulated melting point, and leaves cleaned Vgases free or relatively free from heavy tar and pitch constituents, but containing a large proportion of oil vapors which can be subsequently recovered therefrom by cooling yand co-ndensation.

'.The scrubbing of the gases at a high tein- 'perature can be effected with hot tar or pitch, and further distillation of the tar or pitch may take place during such scrubbing. lf cold tar is `employed in the scrubber, it may. cool the gases too much and result in condensation of too great a proportion of the oil content carried by the liot gases. It is accordingly desirable, if tar is employed, to preheat the vtar to a sufciently high temperature to avoid or prevent or minimize such condensation. Instead of using tar, hot pitch can be employed, and the pitch can be recirculatedthrough the scrubber, with temperature adjustment, by heating or cooling, to maintain it at a substantially constant high temperature. The pitch produced in the collector main may be employed in the scrubber for scrubbing and cleaning the gases, particularly as a large excess of hot pitch is kept f' sufficiently high in circulation through the collector main. The pitch circulated may be of similar temperature and composition to that scrubbed from the gases, but it is not essential that it should be, and more or less distillation of the pitch or tarmay take place in the scrubber simultaneously with the scrubbing and cleaningof the ofases and the removal of snspended pitch particles therefrom.

The meltiz'ig point of the pitch produced from the ga es in the scrubber can be regus lated by regulating ,the amount and teniperature of the scrubbing pitch employed, anda-lso by regulating the temperature of the gases passing through the collector main and into the scrubber. l/Vhen the gases are not scrubbed with tar or pitchin thecollector main, but have on y surface contact with the river of hot tar or pitch circulating therethrough, they pass throu the collector main and enterthe scrubberat a high temperature, to enable them to distill tar or pitch and remove a considerable amount of oils therefrom, without cooling the gases below the temperature at which they will retain a large proportion of oils in vapor form. The scrubber in such case is an effective still for distilling tar to produce pitch, or for distilling pitch to produce pitch of higher melting point, simultaneously with the recovery of pitch from the gases.

The invention can be applied to ordinary coke oven plants such as Semet-Solvay, Koppers plants, etc., as Well as to gas retort plants, without any considerable modification thereof, the usual standard equipment being employed with the addition of a scrubber or scrubbers for the purpose of cleaning the gases and of means for circulating tar and pitch through the collector main. Thus, the ovens of the battery may be connected in the usual manner by uptake pipes and goosenecks to the collector main and the gases may be conveyed therefrom through the scrubber or scrubbers and thence through a cross-over main to the ordinary condensing system. Insulation of the uptake pipes, collector main and scrubbers, etc. may be necessary or desirable to insure treatment and utilization of the gases while still at a high temperature. Suitable storage tanks for the tar or pitch to be circulated through the collector main and a pump or pumps with connections to the collector main will be provided to permit the maintenance of the required volume of tar or pitch in the main during the operation thereof.

The scrubber is disposed preferably closely adjacent to the collector main in order that the temperature of the gases may not be reduced unduly before removal of the pitch constituents is accomplished. The scrubber may be insulated to prevent loss of heat from the gases.

The scrubber may consist of a suitable tower through which the gases ascend in con-v tact with a descending stream of tar, pitch or oil flowing over suitable baffling devices to insure intimate contact between thetar or pitch and the gases inthe scrubber. The tar or pitch may be Withdrawn from the scrubber and returned for further use therein.

The scrubber may in some cases be operated at a temperature equal to or somewhat higher than the gas temperature and the tar, pitch or oil supplied thereto will in such cases be at such a temperature as to avoid reduction of the quantity of the oil vapors in the gases or to add to the quantity of oil vapors, due to distillation ofthe scrubbing medium. The tar, oil or pitch may be heated by a heat exchanger supplied With heat through any suitable medium.

The scrubber may be used also as a means for altering the composition of the scrubbing medium as well as for condensing vapors and for removing suspended pitch particles-from thegas stream. l If,7for eX- ample,.-it is desiredV to convert'an oil or tarry oil of .relativelyfvvide boiling lrange into an oil of relatively narrouT range,and combine it 'atthe same timev with heavy tar or pitch from' the gases-the `oilwill be circulated through the'scrubberv vat such atemperatureas will cause the light .oil inthe scrubbing oil-,to be' labsorbed by the gases. A. Likewise, the .gases may-give up tothe scrubbing oil some ofthe heaviercondensablevapor Well as suspended heavy pitcher tar particles.' The scrubbingoil. Wil-ltjhusbe 'freedof light oils to the desired'extentand will be enrichedin heavy oils-and heavytaror pitch constituents.v The gases will be enriched .in/light oil vapors and will be freedrom-pitch and to #some extent ingjrecovered together lwith admired pitch as Y aliquidproductfat the bottom otl the scrubber and .the i lowzerboiling oils being vvvithdraWn as vapors With .the gasesf The scrubber in such acase functions some- `Whatas a rectification column in that it-provides for a partial separation of light from heavy o ils.' [t Will be understood that the scrubber may be operated in a great many different-Ways, When a scrubbingoil is used, depending upon the type of oil employed for scrubbing, the ,temperature of the oil, the teinperature of the gas at the inlet, the' temperature drop thru the scrubber, the quantity ofY "scrubbingoil utilized, etc. 4In some cases 'the ratio of the sensible heat ot the fixed gases to thelatentheat of 'theoils to be condensedvvill beso high .that alarge amount-of light'oil will be vaporized.l .I In `such a case the method may be modified by fthe removal cfV a part olf-the sensible, heat ofthe gases as sensibleiheat in the oil'rfeed by adding a relatively cold oil.` Iii-'some cases it Will be. desirable evento add With the'oilfa regulated zamount of vvater which upon vaporizati'onivill remove .to the degreedesired the excess of heat in the gases.vv

Tar for pitch at atmospheric temperature or' preheated to agreater ori less extent, may be usedfor scrubbingthe'hot gases leaving the collector main.. -T-he'residu'e dravvn o-:tro'm the rscrubber will .usuallyl beV at' a .higher temperature than the scrubbing medium entering the scrubber, The scrubbing operation may be'y so controlled'that, -duetothe removal or entrained pitchy material from the gases, and/or distillation by the, hotgases in the scrubber, jthis residue Will-be a'pitch ofrelativelyhi-gh melting point. Such a hot residjue,bef,ore;it .has vopportunity to cool, may

advantageously be added'to the tar or pit-ch used for ilushing'the collector main.

`From the scrubber Ythe gases carryingcondensable vapors can be conductedpthru suitable condensing apparatus including coolers, scrubbers, fractional condensers,V .fractionating columns, etc., designed to reduce the temperature of the gases and to cause the separation' oi the oils therefrom.v One total oil fraction may be collected if the gases are cooled in one step to the lowest desiredtemperature. Several oil fractions can be recovered it the gases are cooled by stages in coolers designed for the separate collection-ot` oils corresponding tothe individual cooling steps. Y f f The high temperature of thehot coal distillation vgases coming from ther ovens or retorts, Where cooling is prevented before they reach the collector main, enables them to eect more or less distillation inthe collector main and' still reach and pass through the scrubber. at a suiicientlyhigh temperature, e. g., at a temperature of 150 C. or 250 C. or higher, so 'that .on subsequent coolingt-he'total oil traction may be utilizable as `a creosote oil, containing oils boiling up to and above 350 C.; or by fractional cooling a heavier creosote oil` and a lighter tar acid or carbolic oil can' be recovered at successively loWer temperatures. Simultaneously, pitches of regulated melting points can be produced lby the distillation of tar'in the collector main, kand by scrubbing of the stillhot and pitch-containing gases in the scrubber. Pitches'ofcomlmercial qualities can thus be produced, e. g., pitches of 105.110O F. melting point, or of 150-160 melting point, or of 212er 250 l?. melting point or higherY can be produced by the distillation in the collector main and/or from the scrubber.V Y, Y As examples of the.' operation of the process, the gases can be passed throughthe colllector mainat a temperature such that they leave the main at 300 C. or 350 C. or even 100 C. or higher, With surface contact of the gases With the river of Lhot pitch liovving through-the main and distillation thereof,

and the'hot gases, still at a high temperature, 1

are passed to the scrubber and areY there scrubbed with hot tar-or pitch and treed from suspended pitch particles at a suiliciently hightemperature to leave a large proportion of oils in vapor form. VThe gases and oil vapors may, e.V g., leave the scrubber at a temperaturefaround.15G-160 C. or around 200 C; or even around 250 C. or higher. Pitch will be recovered from the scrubber, and clean oils on cooling of the hot cleaned and enriched gases. lg Y vThe present inventionis Vof more/:or less genera-l application tothefdistillation of tar and oils and the recovery of clean' oils there- 'from and to the recovery ofl pitches and oils l Y directly from coke-oven 'and other coal distillationpgases, and it will be further illustrated by the ifollowing more detailed description taken with the accompanying draw- .ings which show apparatus embodying the invention and adapted for the practice thereof.. It is intended and will be understood that the invention is not limited to the spe- Vcicfdetails of the apparatus as illustrated `in the drawings, in which 1 is a pla-n view of a portion of a vcoke ,oven plant. illustrating the applica- `tion ofthe invention theretoyand Fig. 2 is an .enlarged sectional view illustrating the collector in ain and the scrubber connected therewith.

Referring to the drawings, 5 indicates a battery of coke ovens in which the individual .ovens are connected by uptake pipes and goose-necks to a collector main 7 having a centre box 8. Tar or pitch to be distilled is supplied from a storage tank 9 by means of a pump l0 and a pipeor pipes ll which may deliver the tar or pitch to the opposite ends of the collector main, for example, in

Vsufcientfvolume toA maintain a large supply of hot thnlyliiuid tar or pitch in the Collector main during the operation thereof. The tar or pitch flows through the collector main to the centre box 8 and may be withdrawn therefrom through a pipe l2 and detlivered to the tank 9 from which it may be recirculated for further distillation. A portion ofthe tar or pitchmay be withdrawn from the tank 9 through a pipe 137. Additional quantities Vof tar for distillation can be introduced to the tank 9 through a pipe let. The hot gases flowing through the collector main after Contact with the tar or pitch therein, and after enrichment as the result Yof distillation with oil constituents, are Withdrawn from the centre box 8 While still at al `high temperature, e. g., around 300 tollOOO .C., and are 'delivered through a pipe l5 to the scrubber which may be of any suitable formor construction. Preferably it consists of a shell 16 which may be iilledwith broken v up tile or'otherv suitable material adapted to bring the'gasefs and liquid into intimate contact with each other.y The gas is introduced through an inlet 17 at the bottom of the scrubber .andv withdrawn through an outlet 18 at vthe top thereof. Tar, pitch or oil may be introduced at the top of the scrubber through j a ,pipe lvfromV a source of supply thereof vsuchas a tank 20, apump 2l being provided ;to.permit circulation. A heat exchanger 22 may `rbe provided to permit regulation of the temperatureY of the circulating pitch, tar or oil by the introductionof a heating or coolf ing medium .to the exch anger.

Y Afterflowing downwardly over the bafiies inthescrubber ,the unvaporized pitch, -tar ors-oil can be withdrawn throughV an outlet 23.: 'It mayV be delivered directly to which water or ammonia liquor is separated,

the tarbeing then returnedto the tank. Only in case Water is present in the scrubbing medium, or the gases are cooled sufficiently to condense water from the gases, will water be present with the tar or oil. In most cases, a higher temperature of scrubbing will be used to maintain a large proportion of oils as vapors, andno Water will be present or condensed. The scrubbingmedium may be .addedcontinuously through pump 21 and withdrawn continuously through outlet 23 or the inaterialmay be'V led to tank 2O and recirculated. An additional scrubber or scrubbers (not shown) may be provided if desired, for fractional condensation or multistage scrubbing at progressively lower tem- `peratures.

The gases escaping from the scrubber or scrubbers and being substantially free from tar fog and solid particles, and in most cases still at a high temperature, e. g., 150o or 200O C. or higher, may be delivered through a pipe24c -to a condenser 25. This condenser may be offany suitable form. The condenser shown is of the ordinary wet type which is employed frequently in byproductJ recovery systems. The gases and vapors are cooled therein by contact with grid surfaces wet by sprays of ammonia liquor, for example, and the resulting condensate is withdrawn through pipes 26 to adecanter 27 wherein the oil is separated from the ammonia liquor. The gases leave the condenser through a pipe 28 andare delivered to an exhauster 29 which maintains `the pressure balance in the system. The gases may be conducted thence through the usual equipment (not shown) for the recovery of ammonia, light oils, etc.

The apparatus as described permits the distillation of tar and the production of pitch gases, while still hot, are cleaned by a scrubbing treatment and pitch or tarry oil separated therefrom, leaving clean or relatively 'clean gases and oil vapors. On cooling,

`clean or relatively clean oil condensates are obtained. Thus, the invention permits the' [recovery of clean oils and of pitches having the desired characteristics directly from the coke oven or other coal distillation gases,vas

ywell as the distillation of tar to produce pitch and oils, with resulting saving in the4 Y V"extent, combined with the scrubbing-oi thek Y still Yhot .and tarfog-contain1ng enriched icostof handling-andof redistilling .the ordinary products of a ley-product recovery system. l Y 7 FromV one standpoint, the invention includes improvements in the operation of the 'collector or'hydraulic mains, of coke oven or 4gas retort systems, in which a river of hot tar orl pitch is circulated through the main to keep it free 'from objectionable pitch accumulations,'and vto effect distillation ofthe circ'uliatin'g tar and pitch to*v a greater or less gases to remove the 'suspended pitch or heavy tar particles therefrom, 'Wh-ile' leaving oils largely in vaporv form, and the Vsubsequent condensation of clean` or relatively clean oils therefrom. Separate pitch products can thus be produced'by Y'thedistillation in the 'colf lector main, and from the gases in the 'scrubber, Whilea high yield; `of-"clean oils, suitable for'creosoti-ng or `other purposes, can he condensed as a total/oil fraction, -or fractionally to give a series of foil products. .v

' It' will be understood 'that the foregoing dt-yscriptionV is illustrative of the invention andthat various l'chan-gesmay be made 1n the form and arrangement ofthe apparatus 'and in the operation thereof Without departfrom the invention. 1 claim :f-' i i. Thermeth'od ofpro-ducingjpitch and oils at `coal distillationv plants, which comprises collecting gases from afplura'lity of the ovens orY retorts andipassing them througha common colleetng main lat a high temperature 'su'fllci'entlyv high Vto bring 'about Yeffective distillati-onof tar thereby, circulating through the lcollector main in direct Contact Withsuch .gases a'l 'stream of hot thinly fluid tar and' pitch, 'addingtar-t-o 'the stream and effecting distillation of oils therefrom by direct contact with such gases, withdrawing the: resulting V`stream of pitch from the main, withdrawing 'the gases from the main While still at aI high temperature vand, scrubbing the gases: While still' at ar high temperature with a hotscrubloing medium@separate-suspended pitch par- "ticlestherefrom and leave a: large part ofthe oils-in fthe formfof vapors, and subsequently cooling-the scrubbed gases and vapors to con- `dense'-` oilsy therefrom;

" fZ Them'ethodr'if producing pitch and oils at coaldi'stillati'on plants., which comprises collectingrga'sesfrom fa plurality Jof the ovens lor retortsand p-assing'them through-a com- Ymon collecting main-'at a high temperature `suili'cientlyhigh tio bring abeutj'efective distillati-on Ivof tar thereby, circulating through the "collecter main in direct contact with lsuch gases-a stream of"hot thinly fhiid tar and; pitch 'adding tar "to the stream and eife'etiing distilv lationof oils therefrom by 'direc'tcontact with *such gases, withdravvingithe:resulting :stream offpitchffrom thelrnfain, withdrawing the-gases from' the main whims-11 'at a high tempest ture, and scrubbing such vases with a liquid coal-taroily containing ydrocarbonaceous medium` and simultaneously d'istilling oilsV coal distillation plants Which comprises col` lecting gases froml a plurality' of theovensorl retorts and passing` them through acommon collecting; main While still at a high temperature suliicient to'elfect distillati-chef oils, cir'- 4culat'ingthrough the 'collector main in direct contact with such` hot gases a stream ojf'l'nt thinly ui'd coal-ta-r-oil 'containinghydrocarbonaceous materiali and' effecting Ydistillation of oils therefrom lby directcon'tact with such gases, withdrawing-the resulting streamof pitchrfromV the collector'main,`wthdrawing i 'the resulting gases while still at a high temperature from the collectormainfa-nd vscrub- 'bing them with a hot-pitch scrubbing-medium to separate suspended pitch particles fromthe gases and leave 'a large 'part ofthe-'oils in 'Vapor form, withdrawing the resulting" pitch productv from the scrubbing4 operation, ,and

.subsequently cooling the scrubbed and enriched gases to condense oils therefrom.

4. The method of produ'cingipitchand'oils at 'coal distillation plants which commisescollecting gases .from a plurality ofthe ovensor ret'orts and passing them through 'a common collecting main at 'Jajhigh temperature, 'circula'tin'g through 'the co4lle'ctormainY in" direct Ycontact `with such hotgases a'stream ofi-hot 'thinly liuiidgtar and pitch andeffecting-chstillation of VVoils 'therefrom-bydirectContact with such hot gases, withdrawing thefst'reaim of pitch 'andi re'circulating part of` it, V'together with additionall tar through thecollector main rto elect :further distillat'iomwith'drawing the resulting'gases 'enriche'din oil'va'pors` fronthe 'distillation from the vcollectormain AWhil'eistill at a high temperature, scmbbng thegasesto rem-.ove suspende-d pitch particles therefrom wh/'ile still atY a' high temperature, .and subsequently cooling the 'scrubbed gases to conf densey oils therefrom.

V5. i TheV method of pro ducingj pitch androils fat 'coal r distillation plants whi'ch comprises Veollectiaggases from theovensor retortsand passingthem; thrfmghv aA common-collecting main at a high temperature, suf'eientlyrhigh to fd'still Star, circulating-:through lthe colleetor main in contaet'with such gasesf-ai-fstream `of' het thinly ltar and pitch, adding` tar thereto 'and effecting distillation ofoils'thereatromlbygdirectfcontaot with such gases, withdrawing 'the-resulting" stream.. of pitchlmm the col-lector main, withdrawing the gases from the collector main while still at a high temperature, and scrubbing such gases with the pitch drawn off from the collector main at asufficiently high temperature to separate suspended pitch particles from the gases and leave alarge part of the oils in vapor form, withdrawing the pitch resulting from the scrubbing treatment, and subsequently cooling the gases from the scrubbing operation for the condensation of oils therefrom.

6. The method of producing pitch and oils at coal distillation plants which comprises collecting the gases from the ovens or retorts and passing them through a common collector main at a high temperature such that the gases escape from the collector main at a temperature not less than 300 C., circulating-through the collector main a stream of hot thinly fluid coal-tar-oil containing hydrocarbonaceous material in direct contact with such hot gases to effect distillation of the oils therefrom, withdrawing the resulting stream of pitch from the collector main, withdrawing the gases from the collector main at such high temperature, and scrubbing the gases while still at a high temperature to remove suspended pitch particles therefrom and to leave a large part of the oils in vapor form, and subsequently cooling Y the scrubbed gases to condense oils therefrom.

7. The method of producing pitch and oils at coal distillation plants which comprises collecting the gases from the ovens or retorts and passing them through a common collector rnain at a high temperature suflicient to effect distillation of tar, circulating through the collector main in contact with such gases a stream of hot thinly fluid tar and pitch, adding tar to the stream, withdrawing the gases from the collector main while still at a high temperature and scrubbing them with oils to separate suspended pitch particles from the gases and to effect partial distillation of the oils, withdrawing the residue from the oils-together with the separated pitch, and subsequently condensing the gases to separate oils therefrom.

8. The method of producing pitch and oils at coal distillation plants, which comprises collecting the gases from the ovens or retorts and passing them thru a common collector main at a high temperature such that the gases escape from the collector main at a temperature not less than around 300 C.,

' circulating thru the collector main a stream of hot thinly fluid coal-tar-oil containing carbonaceous material in direct contact with such hot gases to effect distillation of oils therefrom, withdrawing the streamof pitch from the collector main, withdrawing the gases from the collector main at such high temperature, scrubbing the gases to remove suspended pitchy particles therefrom and to leave a part of the oils in vapor form, adding the scrubbing medium to the collector main, after it has been used to scrub the gases, and cooling the scrubbed gases to condense oils therefrom.

9. The method of producing pitch and oils at coal distillation plants, which comprises collecting the gases from the ovens or retorts and passing them thru a common collector main at a temperature sufficiently high to effect distillation of tar, circulating thru the collector main in contact with such gases, a stream of hot thinly fluid tar and pitch', adding tar to the stream, withdrawing the gases from the collector main while still at a high temperature, scrubbing them with oils to separate suspended pitchy particles from the gases and to effect partial distillation of the oils, withdrawing the residue from the oils together with the separated pitch and supplying it to the collector main, and subsequently condensing the scrubbed gases to separate oils therefrom.

l0. A coal distillation plant having a plurality of coal distillation ovens or retorts, a common collecting main for collecting the gases from the ovens or retorts, no means being provided for spraying the gases with a cooling medium as they pass thru the collector main, a scrubber arranged near the collector main to act on the gases as they leave the collector main, means for circulating a stream of hot thinly fluid tar or pitch through the collector main and means for scrubbing the gases in the scrubber with a hot scrubbing medium, a condenser and means for passing the gases from the collector main to the scrubber and from the scrubber to the condenser, whereby the gases are employed for the distillation of tar or pitch in the collector main and are freed from suspended pitch particles in the scrubber before entering the condenser.

In testimony whereof I affix my signature.

STUART PARMELEE MILLER.

CERTIFICATE OF CORRECTION.

Patent No. 1,868,395. July 19, 1932.

STUART PARMELEE MILLER.

It is hereby certified that error appears in the printed specification ofthe above numbered patent requiring correction as follows: Page 7, lines 57 and 58, claim 8, for "carbonaceous" read hydrocarbonaceous; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 22nd day of November, A. D. 1932.

M. J. Moore,

(Seal) Acting Commissioner of Patents.

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