US1920097A - Distillation of tar, etc. - Google Patents

Distillation of tar, etc. Download PDF

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Publication number
US1920097A
US1920097A US326769A US32676928A US1920097A US 1920097 A US1920097 A US 1920097A US 326769 A US326769 A US 326769A US 32676928 A US32676928 A US 32676928A US 1920097 A US1920097 A US 1920097A
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Prior art keywords
gases
tar
still
pitch
distillation
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Miller Stuart Parmelee
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Barrett Co Inc
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Barrett Co Inc
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Priority to US326769A priority Critical patent/US1920097A/en
Priority to FR686723D priority patent/FR686723A/fr
Priority to DEB147376D priority patent/DE655429C/de
Priority to DEB147377D priority patent/DE667188C/de
Priority to NL49462A priority patent/NL27643C/xx
Priority to NL49461A priority patent/NL27856C/xx
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    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10C—WORKING-UP PITCH, ASPHALT, BITUMEN, TAR; PYROLIGNEOUS ACID
    • C10C3/00—Working-up pitch, asphalt, bitumen
    • C10C3/02—Working-up pitch, asphalt, bitumen by chemical means reaction
    • C10C3/04—Working-up pitch, asphalt, bitumen by chemical means reaction by blowing or oxidising, e.g. air, ozone
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10C—WORKING-UP PITCH, ASPHALT, BITUMEN, TAR; PYROLIGNEOUS ACID
    • C10C1/00—Working-up tar
    • C10C1/04—Working-up tar by distillation

Definitions

  • This invention relates to improvements in the distillation of hydrocarbons such as tar, tarry oils, pitch, etc., and includes an improved process and apparatus for such 6 distillation.
  • the present invention provides an improved process and apparatus whereby tar can be distilled for the production of high melting point pitch and distillate oils there- 10 from, with considerably higher yields of distillate oils from the tar-distilled than has heretofore been obtained, so far as I am aware, by any distillation method previously employed.
  • the process of the present invention is a continuous process in which the tar to be distilled is heated by direct contact with highly heated gases, in which the tar is atomized or sprayed into such gases in such volume and with such intensity and uniformity and thoroughness of distribution that the tar is rapidly heated and distilled,
  • the superheated gases quickly cooled to a temperature considerably below their initial temperature, the gases effectively freed from entrained pitch and carbon content, and in which the rate of supply of tar to .be distilled and of superheated gases for the distillation is so regulated that high melting so point pitch can be directly and continuously produced and withdrawn, and so that an unusually high yield of clean oil can be recovered from the distillation by withdrawing the admixed gases and vapors while still at a high temperature and cooling the same to condense the distillate oils therefrom.
  • the present invention provides a particularly advantageous process for the distillation of coke oven tar at a coke oven plant, 4 and enables such tar to be distilled with the production of an unusually high yield of distillate oils, for example, around 75% or more of the tar distilled, and a high melting point pitch, for example, having a melting point around 400 F. or higher.
  • the present process also presents advantages for the distillation of tar where the highest melting point pitch and the maximum oil yield are not to be obtained, and enables tar to be distilled to produce lower melting point perature, e.g. around 550 to 800 C. or
  • such coke oven plants makes use of the hot coke oven gases by introducing them continuously, and at or near their maximum temperature as they leave the individual coke ovens, into a still.
  • the material to be distilled e. g., tar or partially distilled tar
  • the material to be distilled is continuously introduced into the still and caused to fiow therethrough, and atomized or sprayed into the hot coke oven gases with such volume, intensity and uniformity of spraying that the coke oven gases are immediately cooled from their maximum temperature to a materially lower temperature, with simultaneous heating of the tar or pitch and rapid distillation thereof and with such thorough scrubbing of the hot gases as will free them from all or a greater part of their entrained carbon and pitch particles.
  • the resulting admixed coke oven gases and vaporized oils are continuously withdrawn from the still while at a high temperature and subsequently cooled to condense the oils therefrom; and the pitch produced is also continuously withdrawn from the still.
  • Highly heated gases such as those coming from coke ovens, leave the incandescent upper portions of the ovens at a high temhigher, depending upon' the construction of the coke ovens, the coking cycle, the degree of coking, etc.
  • Such highly heated gases are at a temperature above that at which coking of pitch will occur; but such coking is practically eliminated in the present process by subjecting the hot gases immediately, as soon as they enter the still, to contact with an excessively large volume of sprayof tar or pitch which is at a considerably lower temperature and which has adequate capacity for absorbing the heat of the gases as sensible heat and as latent heat.
  • the use of such highly heated gases has the further advantage that the gases, even after beingcooled by distillation of tar and pitch, may still be at a high temperature, for example, when making iO0 F. melting point pitch, around 350 to 400 C. and can be withdrawn from the still at such high temperatures, with advantages which will hereinafter be pointed out.
  • the scrubbing of the highly heated gases is so effectively carried out that the gases themselves are thoroughly cleaned of entrained dust, pitchy material, etc. by the scrubbing operation, and the distillate oils subsequently condensed from the gases are free or substantially so from such pitchy and other extraneous constituents, these constituents being scrubbed from the gases and added to the pitch residue.
  • the present invention provides an improved process for distilling oils, tars, tarry oils, pitches, etc.,from various sources.
  • the tars may be coke oven tars, gas retort tars, water gas tar, or tars from other sources.
  • Tarry oils or other oils can be similarly and advantageously distilled, particularly those which on distillation leave a fluid residue and those which when distilled by the usual methods are subject to a high degree of decomposition with attendant loss in oil yield.
  • the tar may be the total tar produced at the coke oven plant, or it may be the heavy tar separated in the collector main, or the light tar or. tarry oil separated in the condensers.
  • the process is particularly advantageous when. carried out with hot coke oven gases which are available in large volume at coke oven plants, and which contain a large amount of heat which is commonly wasted in the ordinary operation of such plants.
  • the gases from horizontal gas retorts leave the retorts at temperatures of 500 to 700 C. or even much higher and may be used to advantage for distillation of the tar normally collected from the gases on cooling.
  • producer gas which leaves'the gas producer at 500 to 800 C. more or less, and water gas which leaves the machines at 600 to 800 C. are of value for use by my process.
  • These and other highly heated gases are employed in my process for distilling tar, tarry oils, pitches, etc. in a particularly advantageous manner.
  • the apparatus employed, according to the present invention includes a still provided with means for introducing the hot coke oven or other highly heated gases, with means for introducing the tar or pitch or other product to be distilled, with means for withdrawing the distillation residue pro.- quizd, and with means for withdrawing the admixed gases and vapors from the still and for cooling the same to separate the distilled oils, etc. therefrom. If advantage is to be taken of the maximum distillation capacity of the gases the still should be so located that the hot coke oven gases can enter it at a temperature which is not greatly below that at which they leave the individual coke ovens.
  • the still is therefore advantageously placed on top of the coke oven battery and with direct communication from the required number of individual ovens into the still, so that the gases from the ovens enter the still without material
  • the hot gases can however be led to the still at another or different location. Any moderate drop in temperature of the gases can be compensated for by use of added quantity of the highly heated gases.
  • the volume and composition of the coke oven gases given off from adjacent ovens varies, the volume of gases being greater at the beginning of the coking period, after the oven is charged, and being considerably less near the end of the coking period before the oven is pushed.
  • Adjacent ovens are commonly charged at different times so that, for example, at the time one oven is charged, the adjacent oven on one side will be well advanced in coking period, and the adjacent oven on the other side will also be well advanced, but to a different extent. Accordingly, by connecting gas offtakes from the individual ovens so that as the gases from them enter the still, the variations in the amount, composition and temperature of the gases from any particular oven with the progress of the coking cycle of that oven, will be equalized with the gases coming from the other ovens and an approximately uniform volume of gases of approximately uniform average composition can be continuously obtained for the distillation.
  • the individual coke ovens are commonly connected, at one end, with a collector main by individual uptake pipes leading from the individual ovens to the main.
  • the still employed in the present process can advantage ously be located at the other side of the coke oven block and connected with the requisite number of the ovens through individual connecting or uptake pipes so that part or all of the gases from such ovens can be drawn into the still and employed for distillation.
  • the location of the still can vary, depending on the construction of the coke oven plant, the location of the collector main or mains, etc.
  • the still can be located away from the ovens, at one end or side of the block, and connected by a heavily insulated header with the requisite number of ovens, as more fully disclosed and claimed in my companion application, Ser. No. 326,770, filed December 18, 1928.
  • these ovens are valved off from the ordinary collector main so that-all of the gases from those ovens pass through the still and the gas handling system connected therewith.
  • the tar to be distilled may be coal tar containing the usual small percentage of water. Due, however, to the high sensible and latent heat of water as compared with coal tar oils and due'to the low boiling point of water, the distilling capacity of a definite amount of the hot gases can be greatly increased by preheating the tar to remove water from it before it enters the still, for example, to a temperature around but preferably somewhat higher than 100 0.; and the distillation capacity can be still further materially increased by preheating the tar to a higher temperature in order to supply from low temperature sources as much as possible of the latent and sensible heat required for distllling the oils of low and medium boiling points. For example, an increase in preheating of the tar from 100 C. to 200 C.
  • the preheating of the tar, before introducing it into the still, can advantageously be accomplished by heat interchange with the hot gases and vapors after they leave the still.
  • the unusually high temperature of these gases and vapors is such that a very important preheating of the tar can be accomplished at the same time that the gases and vapors are themselves cooled and part of the heavier oil constituents condensed therefrom.
  • Other sources of heat may of course be utilized if desired either alone or in addition to the heat from the distillation gases for preheating the tar.
  • a particularly advantageous method of supplying the tar is to preheat it and then bring it into direct contact with the hot gases and vapors leaving the still. Accordingly, by bringing preheated tar into intimate contact with the escaping gases and vapors, the tar can be partially distilled, and the percent concentration of oil vapors in the gases increased without condensing and removing from the admixed gases and vapors any substantial amount of the heavier vapor constituents carried thereby. The thus preheated and partially distilled tar can then be supplied to the still.
  • the distillation capacity of the still can be greatly increased, and the percentage of oil vapors in the escaping gases and vapors can also be materially increased by such preheating of the tar and introduction of the preheated tar into 0011- tact with the hot gases and vapors leaving the still.
  • the temperatures of the gases leaving the still will vary somewhat depending on the degree of preheat imparted to the tar brought in contact with said exit gases but even with relatively low degree of preheat the exit gas temperature is still sufficiently low as to permit no difficulties in operation.
  • One satisfactory atomizing device comprises a horizontal roll, or a plurality of rolls, or elongated cylinders, rotating rapidly, and with the cylindrical surface dipping into the tar or pitch at the bottom of the still, and rotating at such a rate that it will spray the tar and pitch into the gas space of the still.
  • a roll may be acylindrical roll, with smooth surfaces, or it may have circumferential grooves or ribs or disc-like projections.
  • the invention is not limited to any particular mechanical atomizing device, in its broader aspects, but includes any suitable atomizing means that will insure sufficiently thorough agitation of the tar or pitch and atomizing or spraying of the same into the gases to keep the still Walls flushed with the tar or pitch and to accomplish the sudden cooling of the gases and the rapid distillation hereinbefore referred to as Well as to thoroughly scrub the gases.
  • An atomizing device of generally cylindrical contour, such as a cylindrical roll, either smooth or with circumferential grooves or disc-like projections, is particularly advantageous, since, with such spray devices, the distillation can be readily carried out with a minimum of difficulty from the formation of coke, and with the production of a high melting point pitch and an unusually high percentage of distillate from the tar distilled.
  • the pitch is repeatedly thrown up into the gases and over exposed still surfaces so that in its progress through the still any particular unit of pitch may be thrown into the gases agreat many times. In this way a high degree of intimacy between gases and pitch and a regular and controlled increase in temperature of the pitch is accomplished.
  • the hot coke oven gases With a still connected individually to a plurality of different coke ovens, the hot coke oven gases will enter the still at a corresponding number of points.
  • the tar will ordinarily be admitted at one end of the still and the high melting point pitch withdrawn from the other. If the outlet for the gases and vapors is located near the middle of the still, the flow of gases and of tar at one end of the still will be in a general concurrent direction, and in the other-end of the still in a general countercurrent direction. It the outlet for the gases and vapors is near one end of the still, the pitch may be withdrawn from the same or opposite end, and the tar added at the end opposite the pitch outlet. The general flow of the gases and tar will then either be concurrent or countercurrent.
  • ⁇ Vith a general countercurrent flow of the gases and pitch, the hot gases from the individual ovens first come into contact with hot more or less completely distilled material and flow ina direction opposite to that of the tar and pitch being distilled and leave the apparatus in contact with the incoming tar ofrelatively low temperature.
  • the temperature of the exit gases and vapors will be lower than with concurrent flow and the distillation capacity of the hot gases will be relatively higher.
  • ⁇ Vith concurrent flow the final pitch will leave the still at a lower temperature than in case of countercnrrent flow.
  • the present process and apparatus have proved well adapted for use'on a large commercial scale,
  • the distillation at one plant during a period of about a years time, of two million gallons of coke oven tar with the production of nearly one and one-half million gallons of distillate oil and with pitch having an average melting point of around 380 F.
  • Oil yields from the coke oven tar distilled have been obtained of or more over long periods of time, with the production of pitch of melting point around 400 F. or higher.
  • Pitch of 435 and 450 F. melting point has been made over considerable periods of time.
  • the coke oven gases entering the still have been at a temperature around 550 .C. or higher.
  • the temperature of the gases and vapors leaving the still has varied, for example, between 350 and 400 C.
  • the gases and vapors had an outlet temperature from the still of about 306 C. and the pitch leftthe still at a temperature of about 328 0.; while with pitch of 400 F. melting point the gases and vapors left the still at a temperature of about 324 C. and the pitch left the still at a temperature of about 355 C.
  • the still employed was about 20 feet long, of rectangular cross section about 3% feet wide and high and with six ovens connected by individual uptake pipes with the still.
  • the total distillate produced by the present process which may represent as much as 75% or more of the tar distilled, can be condensed as a single composite oil and employed, for example, as creosote oil; or the admixed gases and vapors can be fraction dependin ally cooled and fractionally condensed and a plurality of oil fractions recovered.
  • a sample of the oil produced showed a sp'eclfic gravity at 38 C. of 1.110, only a trace of free carbon and, when subjected to dlstillation in accordance with the A. S. T. M.
  • the percentage of oil obtainable from coke oven tar from one plant may not represent that obtainable from another plant operating with diiferent types of ovens upon diiferent coals and with a coking period extending over a diflt'erent period of time, or with ovens of varying dimensions.
  • Fig. l is a plan, with parts broken away, of part of a coke oven plant, showing part of the ordinary by-product recovery system and also showing the improved apparatus or the present invention;
  • Fig. 2 is an enlarged vertical sectional view of one type of still embodying the invention
  • Fig. 3 is a partial sectional view taken on the line 33 of Fig. 2;
  • Figs. 4, 5 and 6 are vertical sectional views showing modified forms of settling chambers or towers adapted to replace the tower shown in Fig. 2;
  • Fig. 7 is a horizontal view taken on the line 7-7 of Fig. 2;
  • Fig. 8 is a partial sectional view taken on the line 8-8 of Fig. 2;
  • Fig. 9 is a transverse sectional view taken on the line 9-9 of Figs. 7 and 8;
  • Fig. 10 is an enlarged view partially in section showing one type of fractional condenser
  • Figs. 11 and 12 are horizontal sectional views taken on the lines 1111 and 1212 respectively of Fig. 10;
  • Fig. 13 is a diagrammatic view showing the still and condensing system of Figs. 1 to 3 and 7 to 12.
  • Fig. 14 is a diagrammatic view of a still adapted for countercurrent operation
  • Fig. 15 is a similar view of a still adapted for partial concurrent and partial countercurrent operation
  • Fig. 16 is a diagrammatic View of a still adapted for concurrent operation, with provision for supply of tar directly to the still or to the tower and with an indirect down draft condenser;
  • Fig. 17 is a diagrammatic view of two stills, one adapted for concurrent'operation and one for countercurrent operation, with provision for supplying tar to both, and for drawing ofi' pitch from both or for distilling the pitch successively in the two stills. This view also provides for direct fractional condensation of oils;
  • Fig. 18 is a diagrammatic View of two stills adapted for countercurrent operation, with flow of pitch from one to the other, and with separate gas and vapor outlets, and provision for preheating the tar by indirect contact with the hot vapors and gases from both stills.
  • a coke oven block or battery is indicated conventionally at 1, and part of the conventional by-product recovery system is illustrated in Fig. 1, the individual coke ovens 2 having uptake pipes 3 leading to a collector main 4 common to a number of ovens of the battery.
  • the cross over main 5 connects the collector main with the condensers 6 and the gases then pass through the exhausteral'. to the ammonia absorber, the henzol scrubber, etc.
  • ammonia liquor, or ammonia liquor and tar are introduced into the collector main to cool the gases and keep the main flushed.
  • a drain for the tar and ammonia liquor is indicated internal uptakes 21.
  • the condensers 6 which may be direct condensers, are provided with means for drawing off the cooling liquids and light tar into the decanter 11 from which the ammonia liquor collects in a suitable receptacle (not shown) and the light tar in receptacle 12.
  • This still 20 is of rectangular cross section and is of such a length that four uptake pipes from four individual ovens pass upwardly into it, these four uptakes being shown as
  • Two additional up take pipes 22 connect the still with ovens located beyond the ends of the still and these uptake pipes enter the still at its ends.
  • the internal uptake pipes 21 have lateral openings into the still and closures 23 operated by operating handles 24 for closing individual uptake pipes during the charging of the coke ovens or when it is desired to valve off any oven from the still. Clean-out openings 25 are provided for each of the uptake pipes. It will be evident that the location and arrangement of the uptake pipes leading from the individual ovens to the still can be modified and varied, for example, all of the uptakes may be external uptakes'.
  • the still and external uptake pipes are shown as provided with heavy insulation to prevent or reduce heat losses and reduction of temperature of the gases entering the still.
  • the insulation is omitted and some parts of the apparatus are shown without insulation, but it will be understood that where the lines or parts of the apparatus contain hot tar or pitch, or hot'gases, insulation will ordinarily be provided to prevent heat loss. It heavy insulation is provided, the gases will enter the still at a temperature not materially below that at which they leave the individual ovens and they will thus be available for distillation at their maximum temperature and in a highly heated condition.
  • the outlet for gases and vapors from the still is shown at 27 leading into an enlarged chamber 28 which serves as a settling chamber and which may also serve as a distillation chamber for preheating and distilling tar, as hereafter described.
  • a baflle 29 is located above the inlet to the chamber.
  • the gas and vapor outlet 30 from the chamber 28 leads to a condenser 31, shown as a three stage fractional condenser, from the bottom of. which the cooled gases pass through the pipe 32 to the gas handling system for the coke. oven plant, entering that system between the condensers 6 and the exhauster 7.
  • the condenser illustrated is a three stage condenser having two lower cooling sections 33 cooled by a suitable cooling liquid such as water and with an upper cooling section 34 which serves as a tar preheatcr and as a preliminary con denser for the gases and vapors.
  • the upper tar preheating section has a tar supply pipe 35 leading to the tar coils 36 from which the preheated tar passes through the pipe 37 to the nozzle 38 located in the tower 28 between two packed sections 39 and 40 filled with broken up material or cylindrical rings, e. g. the well-known Raschig rings.
  • the upper section 39 serves to reduce entrainment of suspended particles
  • the lower section 40 serves the same purpose and in addition serves to bring the preheated tar into intimate contact with the admixed gases and vapors leaving the still.
  • the preheated tar is thus partially distilled and the residue collects at the bottom of the tower 28 in the collecting section 41 and flows through the pipe 42 to one end of the still 20.
  • the pitch is granulated by rapid chilling in the water in the trough which discharges the water and granulated pitch into the receptacle 45.
  • This method of cooling and handling the pitch is only one of various methods which can be employed, and, for certain purposes, the pitch can be cooled without admixture of water to give a solidified pitch product free from water.
  • the still 20 are located suitable atomizing or spraying devices for intensively atomizing or spraying the tar and pitch into the gases in such a way that all parts of the gases in the still are thoroughly scrubbed by the tar and pitch, and so that all of the internal surfaces of the still are intensively flushed by an excess of thetar or pitch.
  • lhe mechanical spray devices shown are cylindrical rolls, approximately 10 in diameter, three in number indicated at 48, 49 and 50 and driven at relatively high speed of the still, and the adjustable outlet for the pitch enables the depth to be regulated.
  • the invention is not limited to the preheating of the tar, nor to the introduction of the tar into the escaping gases and vapors to effect partial distillation before it enters the still; but such preheating and partial distillation is particularly advantageous and enables important advantages to be obtained.
  • the condensing system shown in some of the figures of the drawings is a fractional or multistage condensing system, the first stage of which is a preheater for the tar, in which the tar is preheated by indirect contact with the hot gases and vapors.
  • the rate of distillation can be greatly increased by preheating the tar in this way, while the gases are at the same time cooled to condense part of the distillate therefrom.
  • the admixed gases and vapors are then further cooled in the lower stages of the condenser, for example, by indirect contact with cooling coils containing water.
  • the con- (lensing system shown in Figs. 10 to 13 has a water inlet and a water outlet 61 supplying water to the lower cooling sections 33.
  • Three outlets 62, (i3 and (ii are provided for the condensate from the respective sections.
  • Two return pipes 65 and 66 each leading to distributing nozzles 67 and 68, provide for returning the condensate from the upper section into the next lower section where it will blend with the condensate separated in such section.
  • the condenser becomes a total condenser where all of the constituents are condensed and collected together to be drawn off through the bottom outlet 64.
  • the construction of the condenser may vary, and that shown in Figs. 10 to 12 is only one of various types of condensers which can be employed, but it is a valuable type which provides for the preheating of the tar to a high temperature before it enters the still.
  • the gases and vapors may be cooled in condensers of the direct type in which the cooling is by means of ammonia liquor directly in contact with the gases.
  • the cooling of the gases may be done well by the indirect as by the direct-type of condenser.
  • each type of condenser has definite advantages in special cases.
  • the direct condenser is particularly well adapted for use in plants employing the indirect system for recovery of ammonia from the gases, e. g., the Semet-Solvay System, since in that system large quantities, of especially cooled ammonia liquor normally used for cooling the gases are available.
  • the required quantity of this cooled liquor is employed for cooling the gases and condensing the oils from the distillation unit.
  • the ammonia liquor after separation from the oil is returned to'theregular liquor circulation system.
  • the greater proportion of the ammonia is recovered direct as ammonium sulfate by passing the coke oven gases thru dilute sulfuricacid.
  • a relatively small proportion of the ammonia. is recovered from the ammonia liquor condensed from the gases in the collector and crossover mains and in the primary coolers. In this system it is desired to keep the. production of such liquor at a minimum whereas in the indirect system very large quantities of water are added continually to the system for absorption of ammonia.
  • the tar supplied to the still may be the tar collected in the by-product system of the same plant and pumped from the tanks 10 and 12 by pumps 56 and 57 through pipe 58 to the still, or tar from another source of supply can be introduced through pipe 59, or mixtures of different tars, etc., can be introduced and distilled.
  • pitches of special character be obtained from the distillation operation but also the character of the oils recovered may be governed.
  • the light and heavy tars from tanks 12 and 10 may be blended in a tank not shown and then pumped to the still through line 58 or they may be left separate and separately distilled.
  • the light tars will give relatively high yields of lighter oils, relatively rich in tar acids and naphthalene whereas the heavier tars will give relatively lower yields of heavier oils and higher yields of pitch and the oils wll be relatively poor in the tar acids and naphthalene.
  • the oil yields to various pitches be regulated within. limits but also the character of the oils and pitches recovered may be controlled.
  • ⁇ Vhen tar is not introduced into the still tl-u'ough the chamber 28, that chamber may be an open chamber as indicated at Fig. 4. In such case, the tar can be directly supplied to the still at the end opposite the gas outlet.
  • the chamber 28 is such an open chamber, it will serve as a settling chamber where entrained particles of spray from the zone of intensive spraying within the still are permitted to settle out and return to the still.
  • Figs. 5 and (S, modified forms of settling chambers or towers are shown.
  • the chamber 28?) has inclined balliles 39?) over which the preheated tar passes so that it presents a large surface contact with the gases and vapors rising through the chamber.
  • the gases and vapors are thus brought into intimate contact with the preheated tar to eftcctdistillation of it, and at the same time, the arrangment of the batlics assists in the removal of entrained particles of pitch from the gases.
  • the chamber 280 has a series of trays 390 so arranged that the preheated tar flows 'from one tray to the next.
  • the uprising gases and vapors from the still pass over the surfaces of the preheated tar and aid in distilling it.
  • the progressive distillation of the tar to produce pitch results in vaporizing a large part of the oils in the tar to form vapors which admix with the gases and remain in vapor form.
  • the admixed gases and vapors pass from the still to the outlet 27 to the settling chamber 28.
  • a settling chamber such as 28a shown in Fig. 4
  • entrained pitch particles are permitted to settle out and the admixed gases and vapors then pass to the condensing system.
  • chambers such as shown in Figs. 2, 5 and 6 in Fig.
  • the preheated tar when employed with a condenser in which the tar is preheated, the preheated tar is brought into intimate and direct contact with the outgoing gases and vapors with the result that the taris further heated and partially distilled, and the resulting oil vapors added to the gases and vapors passing through the tower.
  • the preliminary heating and distillation of the tar in this way accomplishes a greatly increased distillation by means of heat which would otherwise be lost, and enables the oil vapor content of the gases to be increased, and enables the rate of distillation to be greatly increased, since the preheated and partially distilled tar entering the still requires less heat in the still for its distillation to produce high melting point pitch, than is the case with tar not preheated or partially distilled.
  • the condensing system illustrated in the drawings provides for producing a total condensate by combining the condensate from each of the three sections of the condensing apparatus.
  • the hot coke oven gases pass from the individual coke ovens into the still at practically their maximum temperature.
  • Tar which may be preheated and partially distilled, is introduced continuously into the still and a layer of tar or pitch maintained in the bottom of the still.
  • This tar or pitch is intensively atomized into the gases in the still with such thoroughness of distribution and such abundance of spray that the gases are rapidly cooled from their highly heated condition while rapidly distilling the tar and pitch.
  • all six ovens connected to the still may be' continuously connected, and all of the gases from the sixovens passed through the still; or one or more ovens can be disconnected by closing one of the outlet openings into the still, and by connecting that oven with the ordinary collector main.
  • all six ovens are connected with the still, they are disconnected from the usual collector main, the arrangement being such that all of the-ovens may be connected either with the still or with the collector main, or part with each.
  • the cooling of the hot gases and vapors for the condensation of oils can be so carried out as to produce a single total condensate suitable for example for use as creosote oil; or it can be carried out so as to produce
  • a single total condensate suitable for example for use as creosote oil or it can be carried out so as to produce
  • separate fractions can be drawn off from the individual sections of the condenser illustrated, that is, through the pipes 62, 63 and 64 of Fig. 10, the condensate from the top section being a heavy condensate and those from the lower sections being lighter condensates.
  • Such separate fractions may be used separately or blended in any desired proportion for production of particular oil products for specific purposes.
  • the condenser shown in Figs. 1 to 13 is an indirect condenser in which the gases and vapors do not come into direct contact with the cooling liquid. In some cases it is more advantageous to employ direct condensers in which ammonia liquor or water is brought into direct contact with the hot gases and vapors to effect their cooling and condensation; or to effect fractional condensation by direct cooling with oils of lower boiling point.
  • the apparatus illustrated in Figs. 1 to 13 is an apparatus in which the flow of gases and tar or pitch through the still is of a generally concurrent character, in which the pitch leaves the same end of the still that the hot gases and vapors leave.
  • the hot gases come into contact with fresh tar and with partially distilled tar, and the relatively cooler and more or less saturated gases leave in contact with the more or less completely distilled final pitch.
  • the hot exit gases are not cooled in the' still as much as would be the case if they left the distilling main in contact with the relatively cool and fresh tar, and hence they may leave the still at a higher temperature, in which case they are available for increased distillation of the tar in the chamber 28.
  • the apparatus of Fig. 14 is a countercurrent apparatus in which the gases have a flow which is generally countercurrent to the flow of tar and pitch through the still.
  • the chamber 2852 is shown as an open settling chamber from the top of which the gases and vapors pass to the condenser ,34/1
  • the tar supplied through pipe 35d is preheated by indirect contact with the hot gases and vapors and serves to cool them, the condensate being drawn off through 62d.
  • the gases and vapors then pass to a condenser 33d where further cooling and conlllt ill)
  • a tower of the type shown at 28 in Fig. 1 may be used or a simple settling chamber 286.
  • the condenser shown in Fig. 15 is a condenser cooled by direct contact with ammonia liquor entering at 606 through suitable distributing devices and passing downwardly over grids or other filling material in the tower 340.
  • the admixed condensate and liquor escapes at 646 and the ammonia liquor after separation can be recirculated or other liquor employed.
  • tar directly to one end. of the still and for withdrawing pitch from the other end. Provision is also made for introducing part or all of the tar directly to the tower 28f into direct contact with the hot enriched gases passing through the tower to preheat and partially distill the tar after which the resulting pitch enters the still.
  • the general arrangement of flow of gases and pitch in the distilling main 20 is concurrent.
  • the tar may be in part introduced through the tower and in part directly into one end of the still without preheating.
  • the condenser shown in Fig. 16 is an indirect down-draft condenser in which the cooling liquid flows upwardly in indirect contact with the gases and vapors.
  • the oil condensed in the upper part of the condenser flows downwardly and washes the lower coils of the condenser, thus freeing the lower coils from any danger of naphthalene deposit.
  • pitches of high and low melting point This can readily be accomplished by withdrawing pitch from an intermediate point in the still as well as from the pitch outlet at one end. So also, two or more stills can be provided for distilling.
  • Fig. 17 the stills 20g and 20g are so arranged that the gases and vapors from the still 209 pass through the still 20g. Provision is made for introducing tar directly into each still or directly into the tower through which the hot enriched gases leave the still 20g. Provision is made for drawing .ofl' pitch irom both stills and also for introducing low melting point pitch from the still 20g into the still 20g for further distillation.
  • the arrangement shown provides for counter-current flow of pitch and gases in the still 20g and concurrent flow in the still 20g. Part of the low or intermediate melting point pitch produced in the still 209 can be withdrawn as a separate product and the remainder introduced to the still 209 for further distillation and the production of a higher melting point pitch. This arrangement provides for a combined countercurrent and concurrent flow in a somewhat diflerent manner from that provided for in the arrangement of Fig. 15.
  • the tower 28g of Fig.- 17 may be similar to the tower 28 of Fig. 13 with introduction of tar (with or without preheating and par- 1 tial distillation) through the tower and thence into the still.
  • the condenser shown in Fig. 17 provides for .fractional condensation of the oils by direct contact with oils introduced into the tower and which oils may be themselves vaporized.
  • the fractional condenser 34g is shown as a two-stage condenser with provision for introducing oil into each stage and for withdrawing the condensate from each stage.
  • the two stills shown in Fig. 18 are. arranged to permit production of pitches of dilierent melting points in the difiierent stills, or, by operating the stills; in series,
  • the settling chambers 2871, and 28h are shown without introduction of tar or pitch through them, but the condensers 34h and 3471, are indirect condensers through which the tar is passed in indirect contact with the hot gases and vapors to preheat the tar, which is then fed into the 'still 20h.
  • the preheating of the tar is in a countercurrent manner. Provision is made for discharging the low melting point pitch from the still 20h into the still 20h and also for withdrawing low melting point pitch from this still.
  • Tar (which may or may not be preheated), may be introduced directly into either or both stills.
  • Figs. 13 to 18 which are of a diagrammatic nature, various arrangements are shown of concurrent, countercurrent, or combined concurrent and countercurrent flow of gases and pitch. So also, in these figures there are shown various arrangements of condensers and various arrangements of preheaters for preheating the tar either indirectly or directly before it is in troduced into the still. It will be evident that the diflerent methods of preheating and condensation shown in the different figures can be combined with the different types of concurrent, countercurrent or combined operations, and, for that reason, the different types of preheaters and condensers are shown with different types of gas and pitch flow in the still, instead of showing ,each type of still with the various types of preheatersand condensers which can be employed.
  • a preheating and distilling tower for distilling tar. by direct contact with the hot gases and vapors leaving the still, the action in the tower is a generally countercurrent action.
  • This countercurrent distillation of the tar before it reaches the still may be combined with either a concurrent or a countercurrent distillation in the still, or with a partial concurrent and partial countercurrent distillation, as generally illustrated in Figs. 13 to 18.
  • the pitch leaves the still at a higher temperature and, as above stated, there is greater danger of overheating and coke formation, especially with pitches of high melting point, e. 400 F. Less heat is lost with the pitc and the pitch leaves the still at a lower temperature with concurrent operation.
  • the temperature of the pitch leaving the still, and also the temperature of the gases and vapors leaving the still will vary somewhat with the type of operation, whether with concurrent flow of gases and pitch, or countercurrent flow, or partly concurrent and partly concurrent and partly countercurrent.
  • pitch of around 400 F. melting point may leave the still at a temperature around 360 C. and the gases and vapors may leave the settling tower at a temperature around 325 C.
  • pitch of around 400 F. melting point may leave the still at a temperature around 375 C.
  • the gases and vapors may leave the top of the scrubbing or settling tower at a temperature around 255 C.
  • the pitch of around 400 F. melting point may leave the still at a temperature around 410 C. and the gases and vapors may leave the top of the scrubbing' tower at a temperature around 270 C.
  • temperatures given will vary, depending upon the initial temperature of the hot coke oven gases, upon the character, the temperature and Water content of the tar, upon the extent and efiiciency of the insulation used on the equipment, etc.
  • Thetemperatures given were those which prevailed under existing conditions in apparatus of the types described.
  • the tar When the tar is preheated by indirect contact with the hot gases and vapors in a separate heat interchanger and then introduced directly into the still, as in Figs. 14 and 18, the tar can be preheated to a higher temperature than in the apparatus shown in Fig. 13 where the gases and vapors leave the tower and enter the tar. preheater at a lowor temperature; but with the apparatus of Fig. 13 the preheated tar will be further heated and partially distilled in the tower, as hereinbefore described.
  • temperatures above mentioned will vary with the melting point of the pitch produced and with other conditions of operation, and the particular temperatures above mentioned are intended to be illustrative of the process and not in a limiting sense.
  • the average time required for the gases to pass through the still is only around 1 to 5 seconds, and, during this period of time, the gases are cooled from an average temperature around 600 C. to a temperature e. g. around 250350 C. It will he understood that this period of time will vary, depending upon the initial temperature of the gases, the size of the coke oven,
  • the present invention enables a wide range of pitches and of oils to be produced, and pitches of various melting points as well as oils of various characteristics can be simultaneously produced.
  • Pitches of high melting point and pitches of intermediate or low melting point can be simultaneously produced and withdrawn from the same still or from different stills.
  • reosote oils, tar acid or carbolic oils, or other oil fractions can be directly produced.
  • the oils moreover, will be clean oils substantially free from carbon or heavy pitch constituents, because of the intensive and excessive scrubbing to which the gases are subjected during the distillation, which effectively tar fog particles from the gases.
  • the present invention provides an improved process and apparatus for the distillation of tar and the production of an exceptionally high yield of distillate oils and with production of high melting point pitch therefrom, in which the distillation is carried out by direct contact of the tar with highly heated gases, in which the gases are suddenly and rapidly cooled by extremely intimate contact with an excessive and intensive amount of spray of the tar or pitch to be distilled, in which the tar or pitch in a finely divided form is rapidly distilled, in which the gases are effectively scrubbed and cleaned'by the spray of tar and pitch, in which the distillation is carried out in a continuous manner with the production of a liquid pitch of melting point very much higher than obtainable by any other process with which I am familiar and an exceptionally high oil yield, and with other singular advantages, such as those hereinbefore pointed out.
  • the distillation capacity of the process and apparatus can bc radically increased by preheating the tar and introducing it into direct contact with the hot gases and vapors leaving the still, with resulting material increase in the vapor content of the gases, with partial distillation of the tar so that hot partially distilled tar is supplied to the still, with resulting heat economy in distillation and advantages in subsequent cooling because of the partial cooling of the gases and vapors by the distillation of the tar, and with.other advantages.
  • This preheating and preliminary distillation of the tar by the hot gases and vapors enables the size of the distillation plant to be greatly reduced, or, for a plant of a particular size, enables its dis-' tillation capacity to be greatly increased.
  • the present invention is particularly advantageous for the distillation of coke oven and other tars at cok oven plants and with the use of hot coke oven gases for the distillation. In its broader aspects it includes the employment of other highly heated gases at a similar high temperature. a The process and apparatus are advantageously employed at coal distillation or coal carbonization plants where highly heated fuel gases are produced and are available for the distillation and furnish a source of heat which is commonly lost as waste heat.
  • pitch melting points refer to melting points determined by the method described in Methods of Analysis Used in the Coal Tar Industry, by J. M. Weiss in the J ournal or Industrial Engineering and Chemistry, vol. 10, No. 10, October 1918, page 817.
  • a tar still adapted to contain a small body of tar
  • means for supplying hot fresh coal distillation gases from the ovens or retorts of the plant directly into the still spraying means in the still adapted to spray and respray the tar from the bottom of the still up into the gases passing therethrough in the form of a fine intense spray and with sufficient force to impinge against and wash the interior surfaces of the still, a settling chamber, condensers and means for passing gases and vapors from the still through the settling chamber to the condenser.
  • the method of distilling coke oven tar by contacting the tar with hot coke oven gases in a still comprises supplying hot coke oven gases. from the coke ovens to a still without any considerable reduction of temperature, repeatedly spraying the tar or pitch resulting from distillation of tar into the gases, the volume, thoroughness, and intensity of the spray being so regulated with regard to the volume and temperature of the gases that the gases are immediately cooled to a much lower temperature, regulating the amount of tar supplied so as to obtain distillation therefrom of at least 'percent of the tar as distillate oil and a pitch residue of a melting point of about l00 or higher, maintaining the pitch produced in a fluid state and withdrawing the same continuously from the still, and withdrawing the admixed gases and vapors and cooling the same to separate distillate oils therefrom.
  • the method of distilling liquid hydrocarbons of the class consisting of oils, tars, tarry oils, and pitches by contact with highly heated gases in a still comprises supplying the gases at a high temperature continuously to a still, continuously introducing into the still the hydro carbons to be distilled, maintaining in the still a small body of liquid comprising distillation residue distilled from the hydrocarbons, repeatedly spraying the hydrocarbons and distillation residue into the gases.
  • the volume, thoroughness and intensity of the spray being so regulated with respect to the volume and temperature of the gases that the gases are innnediately cooled to a temperature approaching that of the hydrocarbons with which they are being sprayed, and the hydrocarbons are rapidly distilled to produce a residue, continuously withdrawing the resulting residue from the still, passing the gases and vapors leaving the still through a settling chamber to remove entrained spray particles therefrom, and then cooling the gases and vapors to condense oils therefrom.
  • the method of distilling tar and producing pitch by contacting tar with highly heated gases in a still comprises conveyingthe gases to a still while at a high temperature, spraying tar and pitch into the gases ⁇ the volume, intensity, and thoroughness of the spray being so regulated that the hot gases are scrubbed and immediately cooled to a temperature approaching that of the tar and pitch with which the gases are in contact, regulating the supply of tar so that it is rapidly distilled to produce pitch of high melting point and a high oil yield, continuously withdrawing the pitch from the still, continuously

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
US326769A 1927-03-02 1928-12-18 Distillation of tar, etc. Expired - Lifetime US1920097A (en)

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US326769A US1920097A (en) 1928-12-18 1928-12-18 Distillation of tar, etc.
FR686723D FR686723A (fr) 1928-12-18 1929-12-16 Perfectionnements à la distillation du goudron et des matières analogues
DEB147376D DE655429C (de) 1927-03-02 1929-12-17 Einrichtung zur Destillation von Teer unter Gewinnung von Pech
DEB147377D DE667188C (de) 1927-03-02 1929-12-17 Einrichtung zur Destillation von Teer
NL49462A NL27643C (fr) 1927-03-02 1929-12-18
NL49461A NL27856C (fr) 1927-03-02 1929-12-18

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