US1884220A - Distillation of tar - Google Patents

Description

0611.25, 1932. v A H 1,884,220

DISTILLATION OF TAR Filed May 31, 1929 4 Sheets-Sheet l TIwrr 0/7 ondomer Jaw/ 7, Chamber INVENTOR ATTORNEYS Oct. 25, 1932. A. H. RADASCH DISTILLATION OF TAR Filed May 31, 1929 4 Sheets-Sheet 2 5cm; (Zamer g INVENTOR I ATTORNEYS Oct.'25, 1932. A. H. RADASCH DISTILLATION OF TAR Filed May 51, 1929 4 Sheets-Sheet 3 M14 W BY ATTORN EYS mama a. 25, 1952 UNITED STATES PATENT OFFICE AB'IHOR H. RADASCH, OF SOUTH ORANGE, NEW JERSEY, ASSIGNOB IO THE BASKET-l COMPANY, OI! NEW YORK, N. Y A CORPORATION OF NEW JERSEY DISTIIILATION OI TAB Application filed m 81, 1929. flerial N0.'88'i,868.

- lation plant. The invention includes both the process and apparatus for carrying it out. According to the presentjinvention tars of different composition are; separately recovered from coal distillation gases and se arately distilled to produce oils and pitc es.

The invention is described more particularly as applied to a coke oven plant.

In the operation of coal distillation plants such as coke oven plants, the production of coke is in man cases the primary operation, while in gas p ants, the production of gas is a primary operation. In both cases coke and gas are produced and tar is recovered as a by-product. The tar is recovered by cooling the gases to condense and separate the tar therefrom;

The tarproduced at coal distillation plants is to a large extent used as a fuel, particularly where coke oven plants arelocated adjacent tosteel mills, in which case the tar is extensively employed as a fuel in 0 en hearth and other furnaces. A substantial proportion, however, of the tar recovered as a byproduct at coke oven and gas lants is shipped to tar distillation plants an there subjected tov distillation for the production of distillate oils and pitch residues therefrom.

According to the present invention, the tar is not collected as a total tar product at the coal distillation plants but the tar is collected in separate fractions, one of which is a heavy tar and another of which is a light tar or tarry oil and these res ctive heavy and light tars are separately distilled to pitch and the vapors resulting from the separate distillations are together cooled to roduce one or more distillate fractions. l itches of the same or different melting points may be prepared from the different tars. The distillation of the separate tarfractions is advantageousl carried out directly at the coal distillation plant by subjecting the separate tar fractions to direct contact with the hot coal distillation gases,

distilling the tar fractions.

In the ordinary by-product coke oven plant the gases are collected from a number of coke ovens in acollector main and are there cooled by ammonia liquor or by ammonia liquor and tar and a considerable part of the tar constituents separated from the gases in the form of a heavy tar. The gases are then passed thru a cross-over main to condensers where they are further cooled and where additional tar is separated therefrom usuall in the form of a light tar or tarry oil. The heavy tar separated in the collector main and the light tar separated in the condensers are commonly combined and sold or employed as tar. bining the heavy tar and the light tar, I keep these tar fractions separate and I take advantage of their difierence in character by sub ecting them separately to distillation thereby efiiciently distillin the tar and recovering distillate oil an The vapors resulting from the separate dis tillations may be cooled in the same condensing system to produce a' single oil product or by fractional cooling more than one oil fraction may be obtained.

The heavy tar separated from the gases in the collector main, which in coke oven operations may amount to or or more of the total tar, is relatively low in oil content and relatively high in pitch constituents, while the light tar or tarry oil separated in the condensers of a by-product coke oven battery contains a large proportion of oils and a relatively low percentage of pitch contain only a smaller amount of higher boil ing constituents, is more readily volatilized from such oils than oils of similar boiling range can be volatilized from tars containing a larger percentage of higher-boiling oils, as for example the tar from the collector main, or the tar formed by blending the instead of com-' pitch products.

i the pitch produced by present invention in distilling the lighter 'stilledvfrom a mixture of this tar fraction of lower boilin range and a tar com rising oils of higl er boiling range. T erefore by separate y distilling the tar fractions, the lighter tars are distilled at a lower temperature and the maximum amount of tar ma be distilled with any given quantlty of eat. I

According to this invention the vapors resultin from the separate 'di'stillations are coole to ether in a single condensing apparatus an the distillate oils are obtained as one or more fractions Because of the lower temperature re uired for distillation of the lower boiling oi 5 present in the lower bOllIIlg tar fraction, when the fractions are separately distilled any decomposition of the vapors which would result from heating to higher temperatures is avoided. This results in an increased oil yield and the production of an oilfree from the resultin decom osition products. The amount an composition of the distillation is affeoted correspondingly.

According to the usual continuous methods of distilling tar, it is necessary to maintain the vapors resulting from the distillation at a relatively high tem erature, 1. e., the temperature at which the i herboihng 0113 are distilled from the tar. ccordmg to the action or ii hter fractions of tar, the temerature at w iich the gases are maintained is less than that necessary in those other methods in which a larger amount of heavier tar is blended with the lighter tar. By separately distilling the lighter tar and the heavier tar less decomposition of the vapors results since it is not necessaryto maintain all of the vapors at the higher temperature necessary with such other methods. 7 Al ho the separate distillations of the heavier and lighter tar fractions may be carried out in various ways accordin to this invention, it is advantageous to subject the different tar fractions to distillation I) bringing them into intimate contact with hot coal distillation ases while these gases are at a sufliciently high temperature to efi'ect the de sired distillation. By bringing the tar fractions into intimate contact with the hot gases, for example, by repeatedly spraying the tar into the gases while they are at a high temperature approximating that at which they come from the ovens or retorts, the gases themselves will be scrubbed and freed to a greater or less extent from their heavier entrained carbon and itch particles, while the tar frac tions themse ves will be rapidly distilled with melting point, or pitc resultin enrichment of the gases in oil vapors. ere will be obtained a pitch residue comprising undistilled constituents of the tar and such additional pitch constituents as are scrubbed from the gases. On subsequently cooling the gases, distillate oils will be obtained which are low in tar content and which may be substantially free from tar contaminations, i. e., the oils may be clean oils and directly merchantable as creosote oils or for other purposes.

The heavier and lighter tars may be distilled to pitches of approximately the same es of different melting %oints may be made from the different tars. y combining the ases and vapors resulting from the separate fistillations of the tar fractions and cooling the gases so as to fractionally condense the oils therefrom, I am able to obtain distillate oil fractions directly from the gases while employing only one condensing system. Instead of separately distilling the tar fractions andcomblning the resulting gases and vapors, I may distill the different tar fractions in the same gasesfas, forexample, by first distilling a heavier tar fraction in the gases and then cmp'lloying the partially cooled gases .to disti a tar fraction of lower boiling range. The use of one condensing system obviates the expense of two or more condensing systems which are necessary when the gases and vapors from the sep arate distillations are separately cooled.

The application of the present invention to the usual coal distillation plant does not require any substantial change or modification in the by-product recovery system or in the o eration of such a system so far as the hand ing of the gases is concerned, except for the provision of separate collectin means for collecting and keeping separate t 0 heavy and light tar fractions. Separate storage tanks or collect-ing tanks may be provided for the heavy tar from the collector main and the light tar from the condensers and where two or more fractions are obtained in the condensers, se arate stora e tanks may be provided for t e difierent ractions.

Where the ases from the coal distillation plant are emp oyed for distilling the separate tar fractions, provision must be made for using the gases while at a sufiiciently high temerature. It is advantageous to spray the tar mto the gases and to effect such intimate contact between the tar and gases as to scrub and detar the ases simultaneously with the distillation o the tar. In coke oven plants the gases. leave the coke oven at a high temperature around (SOD-700 C(or higher. By drawing off the gases from the ovens directly into a distillation chamber without permitting an considerable cooling of the gases and b bringing the tar into intimate contact with the gases while they are still at a hi h temperature, the tar can be rapidly dist ed and a pitch residue produced therefrom at the same time that the gases are themselves scrubbed and freed more or less completely from suspended pitch particles and reatly enriched in oil vapors by the disti ation.

' Separate stills are provided for the separate tar fractions and in connection with these stills a single condensing system is provided for the distillate oils resulting from the distillations. By regulating the rate at which the tar is sprayed into the gases, etc., the heavy tar can be distilled in gases which are maintained at a higher temperature and the light tar or tarry oil or the various fractions of 'melting point pitch is produced it is advantageous to pass the tar and the gases thru the still in a enerally concurrent direction. If the tar and gases pass thru the still in a counter-current direction, the hot fresh gases which have a low vapor content come into contact with the nearly completely distilled pitch and difiiculties may arise from over-distillation of the pitch and the formation of coke as a result of the-action of the fresh hot gases on the nearly completely distilled pitch.

. Where, on the other hand, the gases and vapors resulting from the distillation and also the pitch are withdrawn from the same end of the still, the nearly completely formed pitch comes into contact with the nearl saturated gases cooled by previous distillation of tar. The tendency to form coke or carbonaceous deposits is therefore greatly lessened.

" Furthermore, the fresh hot gases come into contact with the fresh tar and the tendency to form coke at this end of the still isalso small.

Where hot coal distillation gases are employed for distilling a total tar such as that produced by blending the various .tars condensed from coke oven gases and where a high melting oint pitch is produced, the itch and enriche gases are advantageous y withdrawn from the same end of the still and the nearly completely distilled tar comes in contact with ases containing a considerable rcentage 0 higher boiling constituents. W ibn the heat of the gases is efiiciently used, the

gases leaving the still are almost saturated with such higher boiling oils. For this reason it is necessary to carry out the distillation at a high temperature in order to distill from the pitch the last traces of higher boiling oils the removal of which is necessary to roduce that particular pitch. On the other iiand, if instead of distillin the total. tar, various tar fractions are istilled, the gases and percentage of hi' her boiling oils as they eave the still. e distillation of the last traces of higher boiling oils, in order to produce a corresponding pitch, takes place at a. lower temperature.

The extent to which the distillation of the respective tars is carried can be regulated and controlled dependin upon the character of distillate oils desire and the pitch residues to be produced. Where the maximum oil yield is desired, both the heavy and light tars can be distilled to pitches of high melting point, for example, around 400 F., or higher. Where pitches. of lower meltin desired, the heavy tar may be su jected to a minimum of distillation to produce such low melting. point pitch. The temperature necessary to distill the lower boiling oils from heavier tar is higher than that required to distill the same oils from a lighter tar but the time during which this heavier tar is heated to eflect the distillation is short. The time reTlired to distill lighter tars to pitch may be onger than the time required to distill heavier tar, but the temperature necessary is not so great.

Where the tar is to bedistilled in hot coke oven gases, and the temperature of the gases is uniform, a large quantity of the light tar may be sprayed into the hot gases in the form of a fine spray, so that the temperature of the taneous y to the temperature ran e desired. The quantit of light tar distille per unit of time, by t is process, will be large.

Li ht tar may advantageously be distilled to a igh meltlng oint pitch, while heavy tar is bein distille to a lower melting point pitch. High melting point pitch may be made from li ht tar. w1th comparative ease and with a re atively high percent recovery of distillate oil. This is due-to the fact that the oils to be distilled are of relatively lower boiling range than are those present in the heavier tars. These oils recoveredfrom the lighter tars are relatively more valuable commercially than are the oils from the heavier tars.

point areases will be reduced almost instan- Therefore the distillation to harder pitches yields valuable oils at high percent and on cooling a composite oil will be pro duced. The gases may first be employed for distillin a heavier tar fraction to a relatively high meTting point pitch, and the resulting gases be then employed for distilling a lighter tar or tarry oil to a pitch of lower melting point, although in such a case some destruction of heavy oils in the heavy tars will be experienced. The vapors from both distillations will be treated in the same condensing system.

Where the collection of separate pitches is not important, but efiicient distillation is desired, the lighter tar or tarry oil may be only partially distilled in the one still to remove in which heavy tar. is simultaneously distilled is particularly advantageous where a high melting point pitch is desired. In such a process, the temperature of the still employed for distilling the tarry oil need not be high enough to produce a high melting point pitch therein, but merely high enough to distill oil the lower boiling oils, and such distillation can be carried on most efliciently therein.

Whether one pitch product is obtained in this manner, or the heavy and light tars are separately distilled to pitches of the same melting point, or pitches of different melting point, separate distillation of the tar fractions is more efiicient than the preparation of corresponding pitches by distillation of a total tar comprising the several tar fractions. The oil yields are higher and the heatconsumption is less.

Theinvention will be further described in connection with a by-product coke oven plant. It will be understood by those skilled in the art that the invention is applicable to other types of coke ovens and other coal carbonizetion plants in which various grades of tar may be fractionally separated from the gases as in a gas collector main and a condensing system.

In the accompanying drawings,

Fig. 1 is a general plan view of a somewhat conventional character showing a byproduct coke oven plant provided with separate collecting and handling equi ment for collecting and keeping separate the eavy and light tars and for separately subjecting these to distillation and combining the gases and vapors resulting from the distillation and simultaneously cooling them in a single condensing system;

Fig. 2 is an elevation of the still shown in Fig. 3 is an end view of the still; and

Figs. 4 and 5 show a modified form of apparatus.

Referring to the drawings, 5 indicates a coke oven battery equipped with the usual uptake pipes 6 and collector main 7 provided with center-box 8, from which a cross-over main 9 connects in the usual way with condensers 10. The goose-necks of the uptake pipes and the collector main 7 may be sprayed with ammonia liquor, or tar and ammonia liquor, through sprays 11 and 12. The heavy tar and the ammonia liquor, which drain from the collector main into the center box 8 are drawn ofi' thru pipe 14 to the decanter 15. Tar and ammonia liquor from the crossover main may also be drawn off into this same decanter thru pipe 16, or may be separately collected, or may be collected with the light tar from the condensers 10. The ammonia liquor and tar will be drawn oif from the decanter 15 to separate storage tanks 17 and 18.

Light tar or tarry oil and ammonia liquor are drawn off from the condensers 10 to the decanter 20 from which the ammonia liquor and light tar are separately collected in the storage tanks 21 and 22. An exhauster 23 is provided for drawing the gases thru the system. Means for recovering ammonia and light oils (not shown) may be provided beyond the exhauster.

Stills 24 and 25 are provided at the rear of the ovens. Each ofithese stills'is adapted to receive hot gases frbm several of the ovens of the battery 5. By properly manipulating the valves 26 in the goose-necks of the uptake pipes 6, connected with the usual collector main and valves 27' and 28 in the goose-necks 27 and the uptakes 28, which connect selected ovens with the stills at the rear of the ovens, the gases from those ovens which are connected with both the usual collector main and one of the stills may be directed to either the usual collector main 7 or one of the stills 24 and 25. By means of these valves the amount of hot gases assing thru the stills may be regulated to e eot the desired distillation.

Each of the stills is provided with agitating means for bringing the tar into intimate contact with the hot gases. For this purpose a smooth roll or cylinder 29 is shown, dipping to a slight extent into the tar in each still. The-gases are sprayed with tar atomized by rapid rotation of this roll. The degree and intensity of spray can be regulated by regulating the extent to which the roll dips into the tar, and the rate at which the roll is rotated. The motor 30 is connected with the main as to result in substantial deterring of the gases. On cooling the resulting gases, clean oils are obtained. Instead of a smooth cylinder, a corrugated or other cylinder, or [m sprays, or other means, may be employed for bringing the tar into intimate contact with the hot gases.

In operating the apparatus tarry oil or light tar-from the tank 22 is pumped by pump 1Q 31 into the settling chamber 35, the amount being regulated by the valve 32 and by the pump. The tar is sprayed into the settlmg chamber thru line 35' and falls upon the baflles 36'. The gas in passing up thru the 115 bafies preheats and partially distills the tar.

The tar is collected at the bottom of the settling chamber and is run to still 25 thru line 25". By proper regulation of the valves 27 and 28 in those uptake pipes connected to the still and the valves 26 in the corresponding uptake pipes connected with the usual collector main 7, gas from the deslred number of ovens can be passed thru the still. By controlling both the supply of light tar and the supply of hot gases and the intimacy of contact, the extent to which the distillation is carried can be governed. a

Pitch resulting from the distillation is drawn oft" thru a coke trap and leveling arm 33' into the tank 33. A portion of this pitch may he returned to the still thru the line 34 for retreatment where this is desirable. The position of the leveling arm 33' determines the level of the tar or pitch in the still. A settling chamber 35 which allows liquid particles entrained in the gases to settle out and to return to the still is shown but such settling means is not always required but is desirable if it is desired to have the oils recovered from the gases by cooling, as free as possible of contaminationby tar or tarry matters.

Heavy tar from the receiver 18 is sup plied thru the lines 39 and 35 to the settling chamber 35. It passes then thru line 24' to still 24 where it is distilled to produce pitch. The extent to which the distillation is carried may be regulated in the manner described in connection with the distillation of the light tars, except that when pitches of high melting point, e. g. 3OO 4OO F. are produced, the pitch is convenientlyhandled by granulating it in the trough 42' in a stream of water. The pitch and water then flow to tank 41 from which the pitch may be recovered. When soft or medium pitches are made they may be collected as liquid pitch in tank 41'.

In case hard pitch or pitch of melting point of 300400 F. is made in still 25, a granulatin'g trough similar to 42 and a granulated pitch tank similar to 41 will be required. In many cases the same tank 41 can be used.

The gases and vapors of oils of lower boiling range from the still 25 are combined with 05 the gases and vapors of oils of higher boiling ran from the still 24 and together they pass to t e condensers 37 which are here shown although othercondensing means may be employed. The gases from the still 24 which are the gases carryin heavier vapors resulting from the distillation of heavy tar may advantageously pass thru a condenser 38 before being admitted to the condensers 37 in order that higher boiling constituents may be recovered from these gases before combining them with the gases and vapors from the still 24, although condenser 38 need not be employed if the collection of a separate heavy oil fraction from the heavy tar is not desired.

In the arrangement described the heavy tar from the collector main will be distilled in the still 24 and the light tar from the condensers will be distilled in the still 25. Pitches which may be of different melting points are produced as residues'of the dis tillations and they are separately drawn ofiI' into the tanks 33 and 41 or 41'. Due to the dilferent composition of each of the tars distilled, each still is operated ditferently. The rate at which the tar is fed to each still, the rate at which pitch is withdrawn, etc, are varied to produce the desired distillation in the still.

Where only one pitch product is desired, and particularly where a high melting point pitch is desired, the light tar may advantageously be subjected to a partial distillation in the still 25 to remove only the ligher oils therefrom. This partly distilled residue is then passed thru the line 43 to the still 24 and "further distilled therein simultaneously with the heavy tar from the collector main. In this method of operation, the condenser 38 may advantageously be employed to condense the higher boiling oils resulting from the distillation of the residue carried over by the line 43 to the still 24 and the higher boiling oils contained in the heavier tar. The lower boiling oils are collected in the condensers 37 which are common to both stills. According to this method, the total pitch residue from the distillation of both tars will be produced in the still 24 and will be drawn oil as a total pitch product into the tank 41 or into tank 41'. Where only a part of the pitch from the still 25 is further distilled in the still 24, dilferent pitch products will be obtained in the tanks 33 and 41 or 41'.

Figs. 4 and 5 show a modified form of apparatus in which the same hot coal distillation gases are employed for distilling tars of different boiling range. The hot gases from selected ovens of the coke oven battery 50 pass through the uptake pipes 51 into a hot gas header 52 and thence into the still 53. From this still the hot gases pass to the still 54 and from there to the condensers 55 and 56. An exhauster 57 is shown for drawing the III a] k ammoinsulated as s own at 58 and the stills 53 and 54 may also be insulated to advantage. Each of the stills is equipped with a spray roll as shown at 59 and 60 driven by a motor in the manner described in connection with the stills 24 and 25 of the preceding figures.

The gases from the ovens of the battery not sent thru the hot gas header 52 are collected in the collector main 61. They are cooled in the ordinary manner as with ammonia liquor supplied from the line 62. The ammonia 1i uor and heavy tar which separate in the odilector main are drawn off into the decanter 63. The tar is as arately collected in the storage tank 64. rom the collector main 61 the gases pass to the condensers 65. Tarr oil and ammonia from the condensers are co lected in the decanter 66. From this decanter the tarry oil is separately collected in the storage tank 67. This tarry oil is lighter than the heavy tar collected in the tank 64 and comprises oils of lower boiling range than the oils contained in the heavy tar.

The heavy tar from the tank 64 is distilled in the still 53. This tar is supplied thru the line by the pump 71 and sprayed into the tower 72 thru which the hot gases and vapors from the still 53 pass on the way to the still .54. The tar is advantageously collected in the bottom'of the tower and fed thru the line 7 2 to the still 53 at the end at which the hot gases enter from the hot gas header 52. The tar is sprayed up into the gases by the roll and the gases, are scrubbed and substantially detarred and the heavy tar is distilled. The pitch producedis withdrawn thru the adjustable levellin arm 74 and collected in the trough 75. he gases enter the still 53 at a high temperature and the heavy tar may be distilled to pitch of a high melting point within the still 53.

Where a bi h melting point pitch is produced it may granulated by sudden cooling in a stream of water, supplied thru the pipe 75'. The granulated pitch and water are drawn ofi thru the trough into suitable means for the separation of the pitch and the water.

The gases leavin the still 53 and the tower 72 are only artial y cooled and only partiall saturate with oil vapors. They ass to the still 54 where they are employed or distilling oils of lower oiling range from the tarry oil. The tarry oil is supplied from the storage tank 67 to the still 54 thru the line 76 by means of the pump 77. The tarry oil is preferably sprayed into the gases in the tower 73 thru which the gases and vapors pass as they leave the still 54. The tar is partially distilled in the tower and the residue may be drained directly into the still or it may be drawn off from the bottom of the tower by means similar to those shown in tower 72 and admitted to the still at the end at which the gases and vapors from the tower 72 enter the still. The gases and vapors enter the still 54 thru the main 78.

According to the arrangement shown in the drawings, the tarry oil is sprayed into the gases and va rs in the tower, and drains into the still t ru the main 7 9 connecting the tower with the still 54. Within the still the tarry oil is brought into intimate contact with the hot gases and vapors by means of the rapidlyrotatingk roll 60. The gases and vapors entering t 0 still 54 thru the main 78 ave been somewhat cooled. They are only partially saturated with oils as a result of the distillation in the still 53 and are employed for distillation of the tarry oil in the still 54. The extent to which the tarry oil can be distilled depends upon the extent to which the.

at which the tarry oil is supplied to the still 54, its tern erature, etc. The pitch produced in the still 54 ma be a low meltingipoint pitch or a pitch 0 higher melting point. It is withdrawn from the still thru the leveling arm 80. Where a pitch of low meltin point is produced, it may advantageously e collected in a cup such as the cup 81 and drained into the tank 82.

v The hot distillation gases are first employed for distilling tar from the collector main. They are then brou. ht into intimate contact with the tarry oil an the tarry oil'is distilled. The sea carrying vapors resulting from the disti ation of the heavy tar and tarry oil pass thru the tower 73 thru the main 83 into suitable condensers. Indirect condensers 55 and 56 are here shown for fractional cooling of the gases and vapors and the recovery of se arate clean oil fractions. The cooling may so regulated that creosote oil is condensed in the condenser 55 and collected in the storage tank 84 and an oil boilingin the range of carbolic oils separates in t e condenser 56 and is collected in the storage tank 85. Means for the recovery of ammonia, etc. may be located be end the exhauster 57.

Where further istillation of the pitch resultin from the distillation of the tarry oil is desired, this pitch may be further distilled in the still 53. For this purpose the line 86 and um 87 are shown connecting the tank 82 with t e line 7 2 which conveys the undistilled. residue of the heavy tar from the tower 72 to the still 53. With such equipment heavy tar from the storage tank 64 may be reheated and partially distilled in the tower 2 and then brought into the still 53 thru the pipe 7 2'. This heavy tar which has been partially distilled and preheated is mixed with the pitch from the still 54 su plied thru the line 86 from the tank 82. Thls pitch is advantageously pumped to the still 53 while it isstill hot. The gases and vaporsresulting aaaaeae from this distillation pass thru the tower 7 2 to the still 54 where they are employed for distillation of tarry oil from the tank 67.

' It will thus be seen that the present inven- 5 tion takes advantage of the fractional separation of tar in the by-product recovery system of a coal distillation plant to produce two or more separate fractions, keeping these frac tions separate and subjectingthem separately to distillation for the production of distillate oils and one or more pitches, and cooling the vapors from the separate distillations in a singlecondensing system to produce one or more distillate oils. 7

While I have described the invention more particularly in connection with a coke-oven plant, it will be understood that it is applicable to other coal distillation plants, as gas retort plants, etc.

I claim:

1. The improved method of producing distillate oils and pitches from coal tar which comprises 'fractionally condensing the tar from hot coal distillation gases and thereby producing a plurality of tar fractions,including a heavy tar and a light tar fraction, subjecting the light tar to distillation to separate lower boiling constituents therefrom and to produce a heavy tar or itch, combining such 80 heavy tar or pitch with the heavy tar fraction and distillating the mixture, and vcornbining the gases and the vapors resulting from the distillations and cooling them to separate distillate oils therefrom.

2. The improved method of producing distillate oils and pitch from coal tar which comprises fractionally condensing tar from hot coal distillation gases and thereby producing a plurality of tar fractions including a heavy 4 tar and a light tar fraction, separately distilling the heavy tar and light tar fractions,

partially cooling the vapors resulting fromthe distillation of the heavy tar fraction to separate a heavy oil, combining the resulting vapors with the vapors from the distillation of the light tar fraction and cooling thecom bined vapors to produce distillate oils.

3. The improved method of producing dis tillate oils and pitch at a coke oven plant which comprises fractionally recovering tar tar, subsequently further coeling the gases to separate a li ht tar or tarry oil, keep ng the heavy tar and tarry oil separate, bringing the heavy tar into direct and intimate contact with hotcoal distillation gases whereby the tar is distilled and a pitch is produced, bringing the gases and vapors resulting from this tar fractions into direct and intimate contact,

in series, with the same hot coal distillation gases, uniting the pitch produced by distillation 'of one of the tar fractions with the other tar fraction and distilling it therewith to produce a pitch product, and cooling the gases and vaporsresulting from the distillationsin a condensing system to separate distillate oils.

In testimony whereof I afiix my signature.

ARTHUR H. RADASCH.

from hot coal distillation gases and thereby producing a plurality of tar fractions including a heavy tar and a light tar fraction, separately bringing the heavy tar and the light tar fractions into direct and intimate contact, in series, with the same hot coal distillation gases, whereby separate pitch products are produced, and cooling the resulting gases and vapors in a condensing system to separate distillate ,oils from the gases.

4. The improved method of producing distillate oils and pitches at coke oven plants, which comprises collecting the gases from a plurality o coke ovens in a gas collector main,

' cooling the gases therein to separate a heavy i

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