US1912394A - Distillation of tar - Google Patents

Description

June fi 1933 s, P. MILLEF:

DISTILLATION OF TAR Filed April 12, 1929 INVENTOR WM M av hm mm an:

ATTORNEYS uents are employed fordistil the resulting gases enriched in condensable Patented"' June 6, 1933 i UNITED STATES swam 2mm mm, or ENGLEWOOD, NEW JERSEY; ABBIGNOB 'ro THE 3mm courm, or NEW YORK, N. Y a coaronarr'on or NEW mm msrrnm'rron or ran.

' Application filed April 12,

This invention relates to a new and improved method of preparing tarry oil and embraces both the method and apparatus.

According to the present invention hot coke oven ases or gas retort gases carrying suspended heavy tar and pitch constiting tar, and

constituents and carrying a reduced er cent of entrained impurities based on t e condensable vapor content of the gases, are combined w1th hot coke oven gases or gas retort gases not so treated, and the combined gases are cooled to condense tarry oils of desiredquality and character therefrom.

According to the present invention I employ coke oven orgas retort gases'at an elevated temperature preferably at a tem perature approaching the temperature of the gases as they leave the ovens or retorts for the distillation of tar, which may be a heavier tar or a tarry oil or even a lowor medium melting .point pitch. By this distillation the condensable vapor content of the gases is increased. Thisenrichment of the gases in condensable constituents reduces the per cent of entrained impurities carried by the gases based upon the condensable vapor con tent of the gases, so that on cooling an oil isobtained which has a relatively low' free carbon content. If the distillation is effected by spraying the gases with the tar, the'spray of tar scrubs entrained impurities from the gases to a greater or less extent. The en richment may be accomplished by an intense spray of the tar which simultaneously enriches the gases and de-tars them, removing substantially all of the entrained impurities from the gases, or the gases may be scrubbed to a lesser extent.

The resulting gases which are enriched in condensable constituents are blended withordinary gases not so cleaned and the distillation and scrubbing are so regulated and ('o-ordinated with the blending operation that the tarry oil roduced on subsequent cooling of the com ined gases, which may he fractional cooling, is a tarry" oil with a l w free carbon content and having other desired characteristics.

1929. Serial No. 854,477.

The free carbon content of the tarry oil produced may be such that the oil as a whole, and the oil even after distillation-t0 remove any excess of low boiling point-constituents,

In making the so called coal tar solutions which are used commercially for creosoting, the greater part of the tar collected from the coke oven gases is distilled and the distillate is blended with a relatively small proportion of undistilled tar usually in the proportions of 80 parts of distillate to 20 parts of tar or less to make the coal tar solutions ofv commerce. amount of taris expensive and when distilled by the usual methods considerable de-. composition of oil takes place during the distillation with resulting loss of valuable oil and corresponding increase in pitch produc tion. When creosoting composition is made according to'this invention, the losses due The distillation of this large to decomposition are lessened or substantially entirely obviated, and operating expenses ma be reduced.

With slight alterations an ordinary coke oven plant, for example, may be adapted for carryin out this invention. For example, in a co e oven battery of sixty ovens, with three gas collector mains, each connected with twenty ovens, one or two of the collector mains may be equipped for d1st ll1n tar. By blending the resulting enrich ases with the balance of the es which ave not been enrichedby the distillation of tar therein, and cooling the combined gases to separate tarr oil, a tarry oil of low carbon content wil be produced.

The tar distilled may be ordinary coke oven tar, which is a blend of various tars obtained in the ordinary operation of a coke oven battery. The heavier tar alone may be distilled, or lighter tar or tarry oils may be distilled. Tar from other sources may be distilled, for example, gas house tar, water as tar, etc. By proper selection of the tar istilled, by regulating the extent to which I the distillation is carried, b regulating the amount of enriched gases b ended with unenriched gases, by regulating the cooling of the blended gases to separate one or more fractions, etc., tarry oil products meeting different specifications may be produced.

The extent to which that portion of the gases employed for distillation is enriched depends upon the temperature of the gases, the nature of the contact efi'ected between the tar and the gases and the length of time during which they are in contact. The extent to which impurities are removed from these gases is likewise dependent upon the nature and degree of the contact between the tar and the gases. For example, such an intense spray of tar may be produced'in the ases that the gases will be thoroughly scru bed and substantially de-tarred during the distillation. Such a spray may be thrown into the gases from a rapidly rotating roll which dips to but a slight extent into a body of the material to be distilled.

The tar may be sprayed into the gases again and again by this means, and the extent to which the distillation is carried thusregulated. A less intense spray may be produced by'nozzles, or paddles, where such thorough spraying of the gases is not contemplated.

The boiling range of the vaporized oils in the ases leaving the collector main in which distillation occurs, and hence the boiling ran e of the oils separated from these gases in t e coolers, is dependent upon the temperature at which the gases leave the collector main. This is controlled by controlling the distillation in the main. Where the temperature of the gases is too high it may further be controlled by cooling the gases in the main by spraying them to a limited extent with water or ammonia liquor, or mixing a limited amount of water or ammonia liquor with the tar distilled. The distilla-ktion ma be in part controlled by this means.

The iling range of the OllS separated from the gases not employed for distillation may similarly be controlled by re ulating the extent to which they are coole in the collector main in which theyare'collected.

The tar to be distilled may be brought into intimate contact with the hot gases by admitting the tar into the gases thru sprays, or by maintaining a body of tar and partially distilled tar in the bottom of the collector main and spraying this up into the gases by suitable spraying means so that the tar is brought repeatedly into intimate contact with the hot gases passing thru the collector main and thereby distilled. Fresh tar may be continuously added to this-body of tar, and finished pitch continuously withdrawn therefrom.

The distillation is advantageously carried out with the gases at a high temperature, approximately that at which they leave the ovens or retorts, and the tar may be distilled to pitch of a relatively high melting point, for example, 250 F., or 390 F. or higher. The distillation of the tar to such a high melting point pitch increases the per cent of higher boiling oils carried as vapors by the gases and the condensation. of such higher boiling oils and their separation from the gases in the condensers produces a tarry oil containing such high boiling oils.

The invention will be further described in .connection with the accompanying drawing which shows in a more or less conventional and diagrammatic manner an arrangement of apparatus suitable for carrying out the improved process at a coke oven plant.

Fig. 1 is a plan view of a coke oven battery equipped with 3 gas collector mains equipped for the carrying out of this inven tion;

Fig. 2 is a detail showing a section thru one of these mains; f

Fig. 3 shows means which may be employed for supporting the shaft 24 in the collector main; and

Figs. 4 and 5 show modified agitating means. v

A battery of coke ovens 5 is shown as being equipped with three collector mains 6, 7 and 8. The ovens are connected with the collector mains thru uptake pipes 9. The collector mains are connected with cross-over mains 10, 11 and 12. The crossover mains are connected with condensers 13. An exhauster 14 is employed for drawing the gases thru the system.

The two collector mains 7 and 8 are e nipped with the usual gas cooling means w ich may be ammonia liquor sprays and the condensate thrown down in these collector mains by the cooling'of the gases is collected in the decanters l5 and 16. One heavy tar tank 17 is shown for collecting the tar from each of these decanters. The tarry oil from the condensers is drawn off into the decanter '18, together with ammonia liquor, and then separately collected in the tarry oil storage tank 19. Two separate tarry oil fractions may be collected where desired.

The collector mains 7 and 8 are operated in much the usual manner except that the degree of cooling of the gases is regulated by control of the quantity of ammonia liquor sprayed into the gases. The collector main 6 is equipped in a novel fashion and is employed for the distillation of tar. The tar to be distilled is pumped from the tank 20 by the pump 20 thru the line 21 to sprays 21' in the main 6. This may be tar from any source supplied thru the line 22, or according to a preferred arrangement, this tar is the tar from the collector mains 7 and 8- andis supplied to the tank from the tank 17 and may be supplied in a regulated amount.

The tar from the tank 20 is pumped into the collector main 6 and there distilled. The

tar may advantageously be spra ed into the hot gases passing thru the col ector main and for this urpose s rays 21' are positioned throughout the length of the main, much as ammonia liquor sprays are ordinarily (placed. The main may also be equippe with agitating means which may comprise paddles such as the paddles 23 on the shaft 24. This shaft is adapted to be rotated at high speed by the motor 25.

Bearings to support the shaft 24 may be positioned at intervals along the collector main. Such bearings may be protected'by suitable means from the spray of tar maintained in the main as, for example, bly a housing such as that indicated at 26 in ig. 3. The shaft may be supported by a bracket 27, in suitable bearings indicated at 28. The bracket and bearings may advantageously be separated on all sides from the collector main by the housing. In this case the shaft will pass thru the housing by means of suitable stufling boxes. The bracket 27 is supported from outside of the main in any suitable manner.

Figs. 4 and 5 show modifiedforms of agitating means which may be employednnstead of the paddles 23 on the shaft 24 for spraying the tar from the bottom of the collector main u into the gases. Vertical shaftssuch as t ose shown at 29 in Fi 4, may be located at intervals alon the co lector main. The shafts may be riven by individual motors 30, or'they may be driven from a common drive shaft. Agitatin means such as the nest of cones indicate at 31 ma be employed for spra g the tar into t e gases. n this case iii gases may be sprayed to'a less extent than with the other devices illustrated due to the tendency of the cones to throw the spra%horidles 33 and driven by the motor 34.

The tar thrown up into the hot ases b any suitable agitatin means, is distilled:

The s ray of-tar pr need within the main shoul be suflicient to keep the walls of the main washed down and to prevent the ac: cumulation of pitch thereon, and sufiicient tar should be circulated thru the main or agitation should be sufiiciently violent to pre vent the accumulation of hard deposits of pitch within the bottom of the mam.

The pitch resulting from the distillation of the tar by the hot gases is drawn ofi thru the ad 'ustable levelling arm 35 into'the tank 36. T 'e position of t e levelling arm controls the depth of pitch maintained within in will tilling the collector main, and thus the extent to which the agitating means dips into the pitch within the main. The hot enriched gases resulting from the distillation of the tar in the mam 6 pass over thru the cross-- over main 10 to the condensers 13 and are combined with. the gases passing over thru the cross-over mains 11 and 12 and together the ases are cooled in the condensers.

T e gases passing over thru the crossover main 10 are enriched in condensable constituents and if cooled would yield an oil of relatively low carbon content. By blending these gases passing thru the crossover main 10 with gases passing over thru the cross-over mains 11 and 12, which latter gases have not been cleaned nor enriched in oil vapors, a gas is obtained which, on coolield a tarry oil, but the tarry oil be olower free carbon content than ordinarily owing to the lower free carbon content of the oils condensed from the enriched ases. By regulating the extent to which t e gases passin thru the cross-over main 10 have been enriched, and the extent to which entrained impurities have been removed fromthe gases during the. enriching operation, and the blendin of these gases with the ases from 11 an 12 in regulated amount, t e free carbon content of the tarry ases from the mains 11 and 12 bly properly arranging the pressures within t e mains gases may be drawn from these other mains thru the main 37 in regulated amount, and blended with the gases from the collector mains 6, 7 and 8 in such amount as to produce a tarry oil of desired properties in the condensers 13.

The sprays 38 are connected with a source of ammonia liquor thru the line 39. The temperature within the main 6, and hence the degree of distillation of tar within the main, can be regulated by spraying a limited amount of ammonia liquor into the gases in the main thru these sp'a s 38. By properly selecting the tar to distilled within the collector main 6 and by regulating the distillation so that desired higher boiling oils are distilled from this tar, the boiling range of the tarry oil obtained from the condensera 13 may be controlled. By distilling a tar which is more or less free from lower .tar from the collector mains 7 and 8, or employing a partially distilled tar and disthe tar within the collector main 6 to produce a pitch of relatively high' melting point, the oils carried b the gases thru the cross-over main 10 will of hi h boiling range and a tarry oil of relative y high boiling range will be collected in the condensers 13. Moreover, if the temperature maintained within the collector mains 7 and 8 is higher than usual as by reducing the amount of ammonia liquor sprayed into the gases passing thru these mains, the tar withdrawn from these mains will be a heavier tar than usual and the gases passing thru the cross-over mains 11 and 12 will contain oils of higher boiling ran e than usual. By proper regulation of t e temperatures employed in the collector mains 7 and 8 and regulation of the character of the tar fed to main 6 as well as the degree of the distillation within the main 6, a tarry oil of higher boiling range may be obtained directly in the condensers 13, even where the cooling of the gases in this condenser is sufficient to produce a total condensate, as:

where the gases are cooled to a temperature in the neighborhood of 45 C. or lower. The process may be so controlled that this tarry oil is of satisfactory boiling range for use directly as creosoting composition.

The distillation within the collector main 6 may be controlled to some extent by blending with the tar to be distilled some of the tarry oil from the tank 19 or other tarry oil containing lower boiling ingredients. Such tarry oil may be supplied thru the line 28 by means of the pump 29.

The enriched gases which do not contain as much entrained matter per unit of condensable constituents as the ordinary gases are blended with unenriched gases in the proportion required to produce a tarry oil product of desired free carbon content. The properties of the tarry oil product may also be regulated by controlling the extent to which the gases are enriched, the tar employed for enrichin the gases, the temperatures at which t e enriched and unenriched gases leave the collector mains, the extent to which the gases are cooled in the condensers, etc. Likewise the number of mains equipped for distillation may be varied to produce greater or smaller quantities of enriched gases than inthe case described in which main' 6 is so equipped and mains 7 and 8 are of the usual type.

I claim: I

1. The method of producing tarry oil of regulated composition in the by-product recovery system of a coal distillation plant, which comprises collecting a portion of the gases from the plant in a collector main While the gases are yet at an elevated temperature, continuously bringing a regulated quantity of tar into direct contact with the gases in the collector main at said temperature, said gases supplying all of the heat 1 uired for distillating ofi volatile oils from t e tar, thereby effecting continuous and regulated distillation of the tar to itch and a regulated uniform enrichment o the gases in their content of condensable oils, retaining condensable oils in the enriched ases, collecting another portion of the gases rom the plant in a second collector main, blending the enriched gases while containing the condensable oils, with the gases from said second collector main, and cooling the combined gases to roduce tarry oil.

2. The method 0 producing a creosoting composition in the by-product recovery system of a coal distillation plant, which comprises collecting a portion of the gases from ovens or retorts o the plant in a gas collector main while the gases are yet at an elevated temperature, continuously bringing tar in regulated amount into direct contact with the gases in the collector main at said temperature, said gases supplying 'all of the heat required for distilling off the volatile oils from the tar thereb effecting continuous and regulated distillation of the tar to pitch and cleaning and uniform enrichment of the coal distillation gases in condensable oils, retaining condensible oils in the enriched gases, collecting gases from another portion of the ovens or retorts of the plant in a second collector main and subjecting them to regulated cooling therein to remove therefrom only a portion of the condensable constituents whereby a substantial portion of the condensable constituents is retained in the gases in the va' or phase, combining the cleaned and enric ed gases while containing the condensable oils, with the gases from the second collector main, and cooling the combined gases to separate therefrom a creosoting composition.

In testimony whereof I aflix my si ature.

STUART PARMELEE MIL ER.

ICS

Images