US1927280A - Distillation of tar - Google Patents

Description

Sept. 19, 1933.

E. H. ELLMs DISTILLATION OF TAR 5 Sheets-Sheet 1 Filed Sept. 2Q, 1929 .R L N O \\\\.K\\\% w W J l 1 .lll. II 1.. \|I. l|| M T? /L ATTORNEYS Y. 2W wrm ATTORNEYS Sept. 19, 1933.

' Filed sept. 20. 1929 3 Sheets-Sheet 3 lNVENTOR 24M/(60% BY f4' ATTORNEYS Patented Sept. 19, 1933 Larissa DISTILLATION 0F TAR Edward H. Ellms, Englewood, N. J., assignor to The Barrett Company, poration of New Jersey New York, N. Y., a cor- Application September 20, 1929 Serial No. 394,022

12 Claims.

This invention relates to the distillation of tar in hot gases, such ashot coal distillation gases to produce a high melting point pitch, and the use of the hot gases and vapors resulting from this distillation for further distillation of tar ito produce a pitch of lower melting point. The invention includes both the process and apparatus for carrying it out.

The invention comprises two distilling operations. In the rst distilling operation a high melting point pitch is produced by bringing the tar into direct and intimate Contact with hot gases. In the second distilling operation a separate pitchproduct, which is a low melting point pitch, is produced by bringing tar into direct contact with the hot gases and vapors resulting from the rst distilling operation. The rst distilling operation is in itself av two step process. In the rst step tar which has been partially distilled in the second step, is brought into direct contact with hot gases and a high melting point pitch is thereby produced. The gases and vapors leaving this first step of the first distilling operation are employed for topping or partially distilling tar in the second step, and the partially distilled tar thus produced is further distilled to pitch of high melting point in the first step of the rst distilling operation.

In the rst step of the first distilling operation, partially distilled tar is brought into direct and intimate contact with hot gases in the form of an intense spray and the tar is distilled to pitch of high melting point. The Walls of the still are continually washed with the tar and pitch to prevent accumulation of pitch on the walls, and the formation of undesirable coke deposits in the still. The intense spray of tar and pitch thrown into the gases produces intimate contact between the gases and the tar and pitch, and gives eicient distillation with high oil yield. If the gases contain entrained particles of tar or pitch, such as are suspended in hot coke oven gases, for example, the iine spray of tar scrubs and detars the gases simultaneously with the distillation so that the gases resulting from thedistilling operations are clean gases and on cooling yield clean oils.

All the heat required for the distillation is supplied by the heat of the gases, or the tar may be preheated before being brought into direct contact with the hot gases. Although there may be some heat supplied to the operation by heating the still externally, this is not contemplated in the preferred form of the vinvention in which the heat is derived. from the heat of the gases and by partial preheating of the tar. In any case thelgases entering the still are at a higher temperature than the gases leaving the still and according to a preferred form of carrying out the invention, the iirst step of the rst distilling operation', in which pitch of high melting point is produced, is eiected by passing the material being distilled and the fresh hot gases through a still in a concurrent direction so that the pitch just before being withdrawn from the still is brought into directl and intimate contact with gases which have been partially cooled and which are partially saturated with oil vapors from the distillation of tar in them, and the hottest and least saturated gases are brought into direct contact with material fed to this step of the distilling operation which comprises constituentsk which are readily volatilized in these hot fresh gases. Overdistillation of the tar or pitch and the formation of coke is thus prevented or reduced to a minimum.

During the rst step of the first distilling opera# tion in which the pitch of high melting point is produced, the material being distilled is sprayed into the hotgases in the form of a fine intense spray and the hot gases entering the still are sprayed with this iine intense spray. The spray is so intense and such a large surface of the tar is exposed to the action of the gases that the gases are quickly cooled and the temperature of the tar is quickly elevated. Rapid distillation is elected. The tar remains in the still during only a short time. This tends to prevent decomposition of constituents of the tar, and a high yield of oils is obtained. Pitch with a melting point of 350 F. or 400 F. or even higher may readily be produced in this first step of this distilling operation.

According to this invention the hot gases and vapors resulting from the first step of this iirst distilling operation in which high melting point pitch isA produced are employed in a second step for heating and partially distilling the tar. The partially distilled tar resulting from this second step is fed to the still in Whichthe rst step is carried out and the partially distilled tar is distilled to high melting point pitch. The enriched gases resulting from the first and second steps of this rst distilling operation are then employed in the second distilling operation for the distillation of tar and the production of a low melting point pitch. n

The rst distilling operation therefore com-i prises two steps, viz. partially distilling or topping the tar and distilling it to pitch of high melting point. During the topping operation the tar is in contact with gases which have been partially cooled, and which are partially saturated and there is no danger of converting the tar to coke, so a less intense spray of tar may be employed than is employed in the rst step of this distilling operation, and the tar and gases may flow in a concurrent or countercurrent direction. This topping step is advantageously carried onin a tower located directly on top of the still in which the high melting point pitch is produced.

During the topping operation, i. e. during the second step o f the first distilling operation, low boiling oils are distilled from the tar and blend with the gases-and vapors resulting from the production of the high melting point pitch, and they are carried to the condensing system without being brought into direct contact with the gases at the temperature at which they are employed in the rst step. The gases leaving the rst step in which the high melting point pitch is produced, may be substantially saturated with vapors of oils of high boiling range, but are not saturated with vapors of oils of lower boiling range. AThe lower` boiling oils are distilled from the `tar into these gases in the topping operation, i.`e. in the second step of this distilling operation. If a large quantity of tar, especially tar at low temperature were brought into direct contact with such gases, the constituents of higher boiling range would be condensed from the gases. The rst distilling operation of this invention, in which high melting point pitch is produced, is so carried on, however, that no substantial amount of vapors are condensed in the second step, that is during the topping operation. The two steps of this rst distilling operation are so regulated that pitch of the desired melting point is produced and substantially all the vapors distilled from the tar are carried from this distilling operation with the gases. These gases and vapors are then employed in the second distilling operation where pitch of low melting point is produced.

When 'a relatively large amount of tar is used in a topping step and brought into direct contact with the hot gases and vapors from the first step of a distilling operation in which pitch of high melting point is produced, this tar maybe partially distilled, but a large quantity of tar cannot be thus partially distilled without reducing the temperature of the gases below the dewpoint of higher boiling constituents present in the gases. When such constituents' are condensed and returned to the still, the melting point of the pitch produced is lowered. By dividing the tar brought into directcontact with the gases and vapors resulting from the production of high meltingpoint pitch fromn partially distilled tar and by bringing one part of the tar into direct contact with the hot gases and vapors resulting from the production of high melting point pitch,

l thereby partially distilling this part, of the tar' and feeding the resulting partially distilled tar to lthe still in which high melting point pitch is pitch of lower melting point is also produced. The A pitch of high melting point is produced ntwo steps and the lower melting point pitch is produced in a second distilling operation.

For example, in the distillation of coke oven tar, according to this invention, hot coke oven gasesmay be employed for the tar distillation and the gases may be so enriched in vapors that on cooling an oil suitable for creosoting composition may be produced, which oil will be free from high boiling, greasy or resinous constituents which are removed from coke oven tar when it is converted to pitch with a melting point of 400 E., and at the same time pitch of this melting point may be produced. The tar to be distilled is divided into two portions, one Yportion is distilled to pitch with a melting point of 400 F. in one distilling operation, which is referred to herein as the first distilling operation, and the balance of the tar is distilled to pitch of lower melting point in another distilling operation, herein referred to as the second distilling operation. For the purpose of illustration, we may assume that a r15% oil yield is obtained when a certain coke oven tar is distilled to pitch with a melting point of 400 F. The oil is carried as vapors by the gases leaving the rst distilling operation and these vapors include greasy or resinous constituents of high boiling range. The second distilling operation is eiected by bringing tar into direct contact with distilling operations except the high boiling constituents which are condensed during the second distilling operation and drawn off as ingredients of the lower melting point pitch, produced in this second distilling operation, are passed to the same condensing system and are cooled to produce clean oil which by fractional condensation may be separated into several oil fractions.

' The heat of the gases and vapors passing from the still in which the second distilling operation is carried out is advantageously employed for preheating by indirect contact therewith all or part of the tar to be distilled. The heat interchanger in which this interchange of heat is effected may serve as a condenser for condensation of oils from the gases at the same time that the tar is heated.

The hot gases employed for the distillation may be hot coke oven gases or hot retort gases or hot producer gases or hot gases from a water gas may be distilled in each of the distilling opera- 1 tions or a different tar may be distilled in each operation. Heavier or lighter tars may be distilled. The tardistilled may be raw tar which contains a small amount of water, or a partially distilled tar or a low melting point pitch.

The second distilling operation may be so con-..`

trolled as to `produce a low melting point pitch suitable for use on roads or a low melting point pitch which on blending with tar may be employed for 'treating roads, or a pitch suitable for fuel, etc, The high melting point pitch may be employed for the many/to which such high melting pitches are put. The distilling operations of this invention may be so controlled as to produce high or low melting pitches of desired properties, or a desired oil or oil fractions. Creosote is usually manufactured to meet specications set b y the consumer. These specications often limit the amount of high boiling constituents, which such oils may contain. This invention, in which constituents of high boiling range are removed from the gases and vapors resulting from the rst distilling operation, provides for the production of an oil containing a higher percentage of low boiling constituents than is usually obtainrable if tar is distilled separately to pitches of --he same melting points and in the same proportions as in the process or this invention, and the distlllates blended.

The apparatus of this invention comprises a still equipped for distilling tar to pitch of a high melting point, and in connection with this still is a supplementary still for topping or partially distilling the tar before it enters the still in which the high melting point pitch is produced. The still in which the high melting point pitch Vis produced comprises means for producing an intense spray of tar in the gases. The still in which the low melting point pitch of the second distilling operation is produced receives the gases and vapors from the still in which` the tar used in the rst distilling operation is topped or partially distilled, and may advantageously be located above it and form therewith a tower up through which the gases and vapors pass.

In the accompanying drawings the invention is further illustrated in connection with the operation of a battery of coke ovens, but it is intended and is to be understood that the invention is not limited thereto. l

In the drawings,

Fig. 1 is a plan of a coke oven battery equipped with stills for carrying out this invention,

Fig. 2 is an elevation partly in section of the apparatus shown in Fig. 1,

Fig. 3 is a cross section on the line 3 3 of Fig. 2, and y Fig. 4 is an elevation of a modified form of distilling equipment.

In the drawings, 5 is a coke oven battery equipped in the usual way with a collector main 6, and a cross over main 7. The collectormain is connected with the individual ovens of the battery through the uptake pipes 8. This equipment may be of the usual type and is shown more or less diagrammatically in the drawings.

At the opposite side of the ovens from that on which the collector main is located is a still 10 equipped for the production of high melting point pitch. The hot gases from selected ovens of the battery pass through the uptake pipes 11-and the hot gas header 12 into this still 10. In the still is the roll 13 which is adapted to be rotated at high speed by the motor 14. The roll is located at one side of the still, as shown in Fig. 3, in order to insure adequate Washing of the walls of the still at the same time that the tar is sprayed up into the hot gases passing through the still. The hot gases and vapors resulting from the distillation in the still 10 pass up into the tower 15. In the tower 15 are two barile sections 16 and 17 which may be Raschig rings or other means for bringing a large surface of liquid into intimate contact with the gases and vapors passing up through the tower.

The tar to be distilled to pitch of high melting point in the first distilling operation of the invention is supplied through the line 18 and sprayed from the nozzle 19 into the gases passing up through the tower. This tar passes down-over the baiile 17. A large surface of the tar is brought into direct contact with the hot gases and vapors leaving the still 10 and the tar is partially distilled. This partially distilled tar is prevented from returning to the still 10 through the passage 20 by the collar 21 and the cap 22. The partially distilled tar collects in the bottom of the tower and is drawn oi through the line 23 and supplied to the still l10 at the end of the still at which the hot gases enter from the hot gas header 12.

The partially distilled tar from the tower is sprayed by the roll 13 up into the fresh hot gases entering the still 10 from the header l2. The tar is sprayed and is resprayed up into the gases as the gases and tar pass through the still. The partially distilled tar is further distilled and pitch of high melting point is produced and at the same time the gases are thoroughly scrubbed and detarred so that entrained solid and liquid particles carried over from the ovens by the hot gases are removed from the gases and drawn oi of the still as a part of the high melting point pitch produced. This high melting point pitch is drawn 01T of the still 10 through the coke trap 24 and the levelling arm 25. It may be chilled by spraying with Water from the pipe 26 in the trough 27. The pitch is collected in any suitable bin 28. The hot gases and vapors resulting from 105 the distillation, carrying constituents of high melting point, pass from thestill 10 through the passage 20 into the tower 15. The still 10, the uptake pipe 11, the hot gas header 12, the tower 15 and the line 23 are all advantageously heavily insulated as shown at 29.

The distillation of the tar supplied through the line 18 and production of high melting point pitch which is collected in the tank 28 constitutes the rst distilling operation of the invention. The rst step of this rst distilling operation is carried out in the still 10 and the second step is carried out in the bottom of the tower 15. The hot gases and vapors resulting from this rst distilling operation pass up through the opening 120 35 of the plate 36, up over the baille section 16 and leave the tower through the main 37. Thev tar to be distilled in the second distilling operation of the invention is supplied through the line 38 and is sprayed into the gases through'the 125 nozzle 39. An yadditional baliie section 40 may advantageously be provided to preventL spray from the nozzle 39 being carried. over by the gases into the main 37 and thence into the condensing system.

The tar supplied through the line 38 passes down over the baille section 16 where a large surface is exposed to the hot enriched gases resulting from the first distilling operation. This causes distillation of the tar, and high boiling 135v vapors carried by the gases from the rst distilling operation are condensed and separate from the gases and blend with the residue resulting from the distillation of the tar supplied through the line 38. 'I'his condensate and the distillation 140 residue constitute the low melting point pitch produced in the second distilling operation. This low melting point pitch collects on the plate 36 and is drawn oir through the line 41 into the tank 41'. The coll/ar 42 and the cap 43 on the 145 plate 36 prevent the low melting point pitch from this second distilling operation from .passing down into the lower part of the tower 15.

The tar supplied through the lines 18 and 38 may be tar from the same source, or tar from diierent sources may be distilhad simultaneously. For example, the tar supplied through 18 may be coke oventar, and gas house tar or a mixture of coke oven tar and gas house tar may be supplied at 38 to produce a road tar or pitch. Where desirable, a portion of the low melting point pitch from the tank 41 may be supplied through the line 18 to be further distilled to produce a pitch of high melting point.

The gases and vapors from both distilling operations pass to suitable condensing means here shown as the direct condensers 44 and 45, where the gases and vapors are sprayed with water or ammonia liquor. The condensate together with excess water and ammonia liquor are drawn oi into one or more decanters 46. 4From the decanters oil fractions are drawn off into the storage tanks 47, or where one oil fraction is desired only one storage tank is employed.

Fig. 4 shows a slightly modied form of apparatus which may be used in connection with a coke oven battery or other source of hot gases as contemplated by this invention. The arrangement except for the heat interchanger in which the tar is preheated may be identical with that shown in Figs. 1 and 2.

The tar to be distilled in the first distilling operation is sprayed into the gases through the nozzle 19a and partially distilled tar from the bottom of the tower is supplied through the line 23a into the still 10a where it is further distilled by the hot gases from the header 12a and high melting point pitch is produced which is collected in 28a. The tar to be distilled in the second distilling operation is sprayed into the gases through the nozzle 39a. The low melting point pitch produced is drawn o into the tank 41a.

According to the arrangement shown in Fig. 4, the tar distilled vrin eaclrdistilling operation is the same kind of tar and it is preheated in the heat interchanger 49 before being brought into direct contact with the hot gases and vapors in either distilling operation. From the line 50 the tar for the first distilling operation passes through the line 52 to the nozzle 19a. Tar for the second distillingA operation passes from the line 50 through -the line 53 to the nozzle 39a. The hot gases and vapors from the tower 15a pass through the main 37a to the heat interchanger 49. Tar is supplied to the heat interchanger through the line 54 and passes through the coil 55 in indirect contact with the hot gases and v'apors passing through the heat interchanger and in a direction concurrent thereto.

The partially cooled gases pass to the condenser 56 where they are sprayed with water or ammonia liquor from the line 57. Oils which separate from the gases inthe heat interchanger 49 are col' lected in the storage tank 58. Lower boiling oils which separate in the condenser 56 are drawn off into the decanter 59 and from there they are separately collected in the storage tank 60.

By preheating the oils as here shown a larger quantity of pitch may be produced than when cold tar is employed, using the same quantity of hot gases. By preheating either the tar for the rst distilling operation or the tar for the second distilling operation a larger quantity of either high melting point pitch or low melting point pitch.l may be produced as desired. In the apparatus shown in Fig. 4 means for preheating both the tar to be distilled to high melting point pitch and the tar/to be distilled to a lower melting point pitch is shown.

Pitch with a melting point of about 400 F.,

pitch of lower melting point suitable for use on roads or fuel, and creosote oil free from higher boiling greasy or resinous constituents may be produced simultaneously from coke oven tar supplied at 54. The high melting point pitch is produced in the tank 28a. The amounts and temperature of tar supplied through the lines 52 and 53 are so regulated that a minimum amount of the vapors of higher boiling constituents which pass from the still 10a are condensed in the lower part of the tower 15a and substantially all of the higher boiling resinous and greasy constituents are condensed and separated from the gases in the upper part of the tower. The resinous and greasy constituents will be drawn oi with the low melting point pitch into the tank 41a. Creosote oil free from such higher boiling constituents is collected in the tank 58. The boiling rangeof any particular oil fraction may be controlled by regulating the cooling of the gases'in condensers and heat interchangers.

At a plant where excess tar is produced, that is, tar in excess of that which can be converted to high melting point pitch,or in excess of that desired as such high melting point pitch, and where the excess tar is to be burned for fuel, this invention may be employed to advantage to produce an increased quantity of oil by topping that portion of the tar to be employed for fuel, and at the same time producing the same'amount of high melting point Apitch as would otherwise be produced, which may be the maximum obtainable with the heat in the gases employed. `10 to 15% of oil may be topped from the tar to be used for fuel without interfering to any appreciable degree with its use as fuel. This topping may be eiected in the top of the tower 15 without in the least decreasing the amount of high melting point pitch produced by distillation in the hot gases.

I claim:

1.V The method of simultaneously producing a high melting point pitch, a pitch of lower melt-- distilled tar of the rst step, and then distilling tar to pitch of `lower melting point,

by spraying tarinto the gases and vapors resulting from thel second step, whereby the tar is partial-ly distilled and higher boiling constituents are condensed and separated from the gases and incorporated with the distillation residue, and drawing ofi the pitchof lower melting point comprising higher boiling constituents condensed from the gases, and then cooling the resulting gases and vapors to condense oils therefrom.

2. The method of producing clean oils and a pitch of high melting point and a pitch of lower melting point by direct contact with hot coal distillation'gases, which comprises producing the pitch-of high melting point in a two-step distilling operation, in the first step spraying partially distilled tar from the second step into-fresh hot coal distillation gases in the form of a fine intense .spray whereby the gases `.are scrubbed and substantially detarred simultaneously with the distillation of the partially distilled tar andv the resulting liquid residue forms the partially n the production of pitch of a high melting point, in the second step spraying tar into the scrubbed gases from the first step thereby producing the partially distilled tar which is further distilled in the rst step and then spraying other tar into direct contact with the gases and vapors resulting from this two-step distilling operation whereby this other tar is partially distilled and higher boiling constituents are condensed and separated from gases, drawing oi a pitch comprising residue from the distillation of this other tar and constituents condensed from the gases, and then cooling the gases to separate clean oils therefrom.

3. The method of distilling tar to Aproduce pitch of7 a high melting point, a pitch of low melting point and oils, which comprises distilling tar to pitch of high melting point in two steps, partially distilling the tar in thesecond step by direct contact with hot gases and vapors from the rst step and spraying the partially distilled tar into fresh hot gases in the first step in the form of a fine intense spray, whereby the tar is distilled to pitch of a high melting point, and producing pitch of a low melting point by spraying tar into the gases and vapors resulting from the two-step distillation,whereby the dis tillation of the tar is eifected and vapors are condensed from the gases and blended with the residue from the last mentioned tar distillation to produce the low melting point pitch, and preheating at least a portion of the tar distilled in the two processes by bringing it into indirect heat interchange relation with the gases and vapors resulting from both distillations and condensing oils from the gases simultaneously with the preheating of the tar.

4. The method of producing a. high melting point pitch and a low melting point pitch from dierent portions of the same tar and also producing oils, which comprises distilling a portion of the tar to pitch of a high melting point in a two-step distilling operation, partially distilling the tar in the second step by direct contact with the hot gases and vapors from the :first step and in the first step spraying the partially distilled tar into fresh hot gases in the form of an intense spray, whereby the tar is distilled and pitch of high melting point is produced, producing the low melting point pitch by spraying tar into the gases and vapors resulting from the two-step distilling operation, whereby distillationv of the tar is effected and' constituents are condensed and separate from the gases and are blended with the residue from the last mentioned tar distillation tar to produce the low melting point pitch, and preheating both the tar distilled to low melting point pitch and the tar distilled to high melting point pitch by bringing them into lindirect heat interchange relation with the hot gases and, vapors resulting from the two distilling operations before bringing them into direct lcontact with the gases, whereby oils are condensed and separated from the gases simultaneously with the preheating of the tar.

5. The method of producing high melting point pitch, low melting pointpitch and creosote oil substantially free from high boiling resinous and greasy constituents, which comprises .distilling coke oven tar to pitch with a high melting point in the neighborhood of 400 F. in a two-step distillingoperation by direct contact with hot coke oven gases, in the second step of the distilling step bringing the partially distilled tar into direct and intimate contact with fresh hot coke oven gases by spraying the partially distilled tar from the second step into the fresh hot gases in the form of a line intense spray whereby the gases are scrubbed and substantially detarred and pitch with a melting point of 400 F. is produced and highboiling greasy and resinous constituents are distilled from the tar, so regulating the amount of tar partially distilled in thesecond step of this distilling operation that substantially none of these higher boiling greasy and resinous constituents are separated from the gases therein, bringing tar into direct contact with the hot gases and vapors resulting from this two-step distilling operation, thereby distilling the tar and condensing substantially all of the higher boiling greasy and simultaneously resinous constituents from the gases and causing them to blend withthe distillation residue to produce a low melting point pitch, and then cooling the resulting gases and vapors to separate an oil substantially free from these higher boiling greasy or resinous constituents, said oil being a creosote oil.

6. A still for producing a high melting point pitch, means for admitting hot gases thereto, spray means therein for bringing the material being distilled into direct and intimate contact with the hot gases in the form of an intense spray, a pitch draw-off from the still, means for drawing olf the hot gases and vapors resulting from this distillation and means for bringing tar into direct contact with them, so as to partially distill the tar,v and means for conveying the residue from this distillation to the still, means for conveying the gases and vapors resulting from this distillation to 'further means for distilling tar, means therein for bringing tar into direct contact with the resulting gases and vapors, and a separate draw-off for the pitch formedtherein, a condenser and means for conveying thereto the resulting hot gases and vapors.

'7. A still, means for passing tar and hot gases therethrough in a concurrent direction and for leaving this still, a draw-off from this means to feed the partially distilled tar to the end of the still at which the hot gases enter, and a further still for producing low melting point pitch into which the gases and vapors resulting from the partial distillation of the tar pass with means for introducing tar thereto and a pitch draw-olf therefrom.

8. A still for producing a high melting point pitch, a hot `gas inlet thereto, a pitch draw-off therefrom, means in the still for bringing the tar -into intimate contact with the gases therein,

`means for topping thetar by direct contact with `the hot gases and (vapors coming from thestill, means for supplying the topped tar to the still, a still for producing low melting point pitch, means for introducing the gases and vapors resulting from the topping operation into this still, means for introducing tar thereto and for withdrawing the low melting `point pitch therefrom, and a heat interchanger for bringing tar irlto indirect contact with the hot gases and vapors leaving theV second still and'means for supplying the heated tar to one of the stills.

9. A still, means for admitting hot gases thereto and withdrawing the pitch therefrom, a tower comprising -two sections, gas and liquid contact means in each section, a gasv main leading from supplying tar to the bottom-'section of the tower above the gas and liquid contact means therein, a draw-off for tar'or pitch from the bottom of Vthe tower to the still, means for supplying tar to the upper section of the tower above the gas and liquid contact means therein, means for withdrawing the distillation residue from the top section of the tower, and condensers with means for passing gases and vapors from the top of the tower thereto.

10. In combination with a coal` distillation plant, a still, means for supplying hot coal distillation `gases from ovens or retorts of the plant to thestill, means in the still for spraying tar into direct and intimate contact with these gases, a pitch draw-01T from the still, 'a saturator, means for passing gases and vapors from the still to the saturator, means in the saturator for bringing tar into direct contact with the hot gases and vapors therein, and means for conveying distillation residue from the saturator to the still, a second still, means for passing the hot gases and vapors from the saturator to the second still, and means for supplying tar thereto and for withdrawing pitch therefrom.

11. The method of producing a high melting point pitch and lower melting point pitch and creosote oil free from higher boiling greasy and p. resinous constituents which comprises distilling tar to pitch of high melting point by bringing it 1,927,980 the still into the bottom ofthe tower, means for" into direct and intimate contact with'hot gases whereby higher boiling greasy and resinous constituents are distilled off from the tar by the hot gases, distilling a suicient volume of tar in the resulting gases and vapors to free them from vapors ofthe higher boiling greasy and resinous constituents distilled oi from the tar and produce a lower melting point pitch comprising these higher boiling greasy and resinous constituents. and then cooling the remaining gases and vapors to produce creosote oil free from higher boiling greasy and resinous constituents.

12. The method of distilling tar by direct contact with highly heated gases, which comprises bringing the tar into direct and intimate contact with the gases in the form of a tine intense spray, whereby the gases are enriched in volatile constituents and pitch of a high melting point is produced, bringing additional tar into direct contact with the hot enriched gases in such a manner as to distill the tar and simultaneously condense higher boiling constituents'out of the gases thereby forming a lower melting point pitch comprising constituents originally present in the additional tar and also constituents volatilized from the rst mentioned tar, separately collecting the two pitch products, and cooling the resulting gases and vapors to condense clean oils therefrom.

EDWARD H. ELLMS.

CERTIFICATE 0F CORRECTION.

Patent No. l, 927, 280.

september 19, 1933.

EDWARD H. ELLMS.

It is hereby certified that error appears in the printed specification ofthe `above numbered patent requiringfcorrection asfollows:

Page 5, line 10, claim 2, before ','gases" insert the article the; and line 55, claim 4, strike out the word "tar";

page 6, line 82, claim ll, for ','and"l read to;

and that the said Letters Patent should be read with these corrections therein that the same may conformr to the record of/ the case in the Patent Office.

A Signed and sealed this 21st day of November, yA'. D. 1933,

Il (Seal) es'l " Fr M. Hopkins Acting Commissioner of Patents.

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