US1844893A - Apparatus for the production and distillation of tar - Google Patents

Description

Feb. 9, 1932. s. P. MILLER 1,844,893

APPARATUS FOR THE PRODUCTION AND DISTILLATION OF TAR Filed Mafrch 5. 1927 3 Sheets-Sheet 1 cn N 'gb w 50mm-Minas C 56731?) Hl/Y ATTORNEYS Feb. 9, 1932. s. P. MILLER 1,344,893

APPARATUS FOR THE PRODUCTIN AND DISTILLATION OF TAR Filed March 5. 1927 5 Sheets-Sheet 2 n INVENTOR jhm/MM WMW ATTORNEYS s. P. MILLER Filed March 5. 1927 5 Sheets-Sheet 5 INVENTOR ATTORNEYS Patented Feb. 9, 1932'- UNITED STATES "PATENT OFFICE STUART MILLER., OF TENAFLY, JERSEY, ASSIGNOB TD THE Bm COMPANY, F NEW YORK, N. Y., A. CORPORATION 0F NEW JERSEY APPARATUS FOR THE PBOUCTIO LND DISTILLATION 0F TAB Application led Iarch -5,

This invention relates to improvements in' apparatus for the distillation of tars, and particularly to apparatus adapted to utilize the heat available in the gases produced in coal-carbonization plants such as coke ovens to distill tar and to produce therefrom oils and pitches. The invention will be described especially with reference to its application to coke ovens. i

In the ordinary operation of by-product coke ovens, the gases produced by the coking operation pass from the individual lovens through uptake pipes and goose-necks to a collector main common to the ovens of the battery. The gases, commonly known as foul gases, leave the ovens at high temperature, e. g., 600 to 700 C. or higher and carry a considerable proportion of tar and oil constituents. Ordinarily the gases are cooled as rapidly as possible to relatively low temperatures, e. g., W-125o C., by the application of the sprays of ammonla liquor, or ammonia liquor and tar, in the goose-necks and collector main. The rapid cooling .causes considerable separation of tar containing the heavier oils in the collector main. Further cooling is effected in the cross-over main which connects the collector main to the condensing system and an additional quantity of tar carrying both heavier and lighter oils is thus separated. Light tar or tarry oil is also collected from the condensers or coolers. The collected tar is ordinarily shipped from the coke-oven plant to a tar-distillation plant for distillation and separation of the oils and the production of pitches of varying qualities. Handling losses, freight charges and distillation costs, including fuel and capital and maintenance expenses for `the special equipment required for distillation, add to the cost of production "of the products of the distillation.

It is the object of the present invention to provide apparatus which permits the distillation of tar at a coke-oven plant, the utilization of the heat of the coke-oven gases for that purpose, and particularly the production by such distillation of an increased quantity of oils together with pitches having the vari- 1927. Serial No. 172,982.

ous qualities and characteristics required by the trade. y

The apparatus of the present invention provides for utilizing the heat of the cokeoven gases as they come from the coke ovens to distill tar and to separate vaporizable oils therefrom by spraying or otherwise bringing the tar into intimate contact with the hot co eoven gases at a temperature sufficiently high to accomplish the desired distillation. The amount of heat available in the hot coke-oven gases from a battery of coke ovens is, however, ,ma-ny times that required forl distillation of the tar roducedby such a battery, andthe present invention is directed more particularly to the utilization of so much of the heat as is required for the distillation of the tar produced by the batter''7 or such additional tar'as may be availabei for distillation. The batteryvmay' operated consequently in the usual manner and without substantial modification of the equipment ordinarily provided except insofar as provision'is made for the distillation of the tar in the manner hereinafter described and the utilization of a portion of the hot cokeoven gases for that purpose.

The battery may be provided with the usual uptake pipes and collector main or mains in which the hot coke-oven gases are subjected to sprays of ammonia liquor, or ammonia liquor and tar, to rapidly cool the gases and thus throw down a considerable portion of the tar and heavier oils in the collector main. The remaining gases ma be further cooled in the cross-over main Wit resulting separation of an additional quantity shipped to the tar distillation plant.

gases.

In the apparatus of the present invention these crude tar products are subjected to distillation at the coke-oven battery by utilizing a portion of the heat of the coke-oven tageously by providing a separate collector main which ma be connected to one or more side of the ordinary collector main, but it may be placed advantageously at the rear of the battery and be connected. to the selected ovens thereof b separate uptake pipes and goosenecks. T e same ovens can be connected also to the usual collector main and valves can be rovided to permit the direction of the gases romthe ovens as desired into either of the collector mains.

IPhe desired distillation of the tar and oil can be accomplished in a variety of ways involving the intimate contact of the gases therewith; for example, by spraying the tar or oilinto the goose-necks leadinglto the separate collector main and into t e separate collector main. Because of the high temperature of the gases, such intimate contact results in effective distillation and consequent separation of the volatile constituents of the tar or oil and the production of pitches or residues of varying consistency, depending upon the regulation of the operation with respect to the quantity of tar or oil and gases employed and the time during which they remain in contact.

The distillation can he promoted by mechanical agitation of the tar or oil in the separate collector main as, for example, by

the provision of a shaft or shafts extending through the collector main and having paddles or other agitating means thereon so that as the shafts are rotated the tar or oil is thrown upwardly into the stream of gases and intimatel mingled therewith. Agitation can also be accomplished by the introduction of compressed gases such as fuel gases, coke-oven gases, or steam into the tar or oil in the collector main so as to throw the tar or oil into the stream of gases. McDaniel ejectors suppliedwith such gases under pressure can be utilized thus to cause an intimate mingling of the tar or oil in finely divided form with the hot coke-oven gases.

Owing to the effective distillation of the tar or o1l in the collector main pitch is produced and there is a tendency for hard pitch to accumulate on the walls of the collector main. To avoid such accumulation of hard pitch it is advantageous to flush all the co1- lector main surfaces with an excess of hot tar or oil orwpitch which ymaygbe introduced through the spray nozzles or through the end of the collector main. The tar or pitch re- This can be accomplished advan-- 1,s44,ses

sulting from the distillation may be withdrawn either continuously or intermittently from the collector main and all or a portion thereof can be recirculated for further distillation and for the purpose of maintaining a sufficient body of tar or pitch in the main.

Since hard pitch is soluble in the hot tar or oil which is sprayed into the collector main or thrown into the gas stream so that the walls of the collector main are washed constantly with hot tar or oil, accumulations of hard pitch therein will be avoided and thevcollector main can be operated, if desired, continuously for the purpose of producing distillates from the tar and oils produced by the entire battery of coke ovens.

Although indiscriminate cooling of the gases in the short collectonmain is to be avoided since the primary purpose is to utilize the heat for the distillation of Atar and oil, it may be desirable to introduce regulated amounts of water or ammonia liquor with the tar or oil which is sprayed into the short collector'main to cool the gases to a predetermined and regulated extent. The regulation of the cooling effect can be accomplished readily with water because of the higher specific and latent heats of the Water and its lower boiling point as compared with tar and oils. It is possible, therefore, to use water or ammonia liquor in addition to the tar or oil in the proportion required to remove all heat-except that needed for the distillation of the tar or oil. When harder pitches are desired less water can be added or none at all and proportionately more tar or oil will be passed through the main. Cooling of the gases to some extent can be accomplished also by the addition thereto of cold gases such as fuel gas, cooled coke-oven gas, etc.

As an example of the operation, a plant comprising a single battery may produce tar and oils in the ordinary manner and the tar or oil or both so roduced can be distilled with the heat provided in the gases from one or more ovens. Moreover, the tar produced by one or more batteries can be accumulated and it can be distilled from time to time in the separate collector main by utilizing the heat from the coke-oven gases supplied to that main. The operation is flexible inasmuch as the gases may be diverted at will from' the separate collector main to the ordinar' collector main when there is no tar to be istilled or when for any reason it is not desirable to carry on distillation in the short collector main.

While the invention is designed primarly to distill the tar produced at a coke-oven plant by utilizing some of the hot coke-oven ases from that plant, it is also possible to istill tar from other sources in the separate collector main. The tar distilled may contain all or practically all of the condensable oils or it may be a heavy tar containing only part of the oils or mlxtures of such tars.

Heavy tar, light tar, or heavy or light tar tort tar, or water-gas tar, etc., can also be distilled. Where blended or composite pitches are desired or composite or blended distillates,two or more different kinds of tar can be distilled separately'at the coke-oven plant or the can be admixed in suitable pro--4 portions an can be distilled together iving directly a composite pitch product. or example, horizontal gas-retort tar with high free carbon content can be admixed with cokeoven tar and the mixture can be distilled to give a composite pitch higher in free carbon than the pitch from the coke-oven tar and to give a composite oil distillate. 4

Tar as commonly produced and collected at coke-oven plants contains more or less water or ammonia liquor admixed therewith. Such tar can be employed directly and dehydrated as well as distilled or it can be partially or completely dehydrated before subjecting it to distillation. The tar can also be preheated in any suitable manner to reduce it to a thinly fluid state which will facilitate the spraying of the tar into the collector main and ensure intimate contact thereof with the hot coke-oven gases. The amount of heat contained in the hot coke-oven gases is,'however, so great that effective dehydration as Well as distillation can be accomplished readily.

In carrying out the process the tar may be broughtinto contact with the hot gases only once or it may be recirculated and brought again into contact with the hot gases to accomplish a further distillation and the production of harder pitches or even pitchesy of modified character such as those having increased free carbon content. This further distillation may take vplace by recirculating the tar or pitch through the same collector main or through another or other systems as, for example, successively through a serles of separate collector mains. By providing separate collector mains, each connected to a s eries of ovens, it is possible to produce distlllates and pitches of different characteristics -simultaneously and by operating separate condensing systems withsuch se arate distillation systems, condensed pro ucts having different properties can be produced simultaneously. By 'regulation o the spraying or agitation of the tar and b y redistillation when necessary, itis possible to regulate the hardness of the pitches produced and to produce softer or harder pitches as desired.

The distillation of tar and oil may be regu.- lated not only for the production of desired distillate oils therefrom but also the production of pitches of varying properties and characteristics. By limiting the time or intimacy of contact or both of the tar or oil with hot gases, the temperature to which the tar is preheated and the temperature to whichA the tar is raised during distillation, pitches of low vcarbon content and oils having definite characteristics can be produced as hereinafter described. When, however, the pitchY first produced is recirculated its temperature will be further raised and the temperature can be increased to'such an extent that more or less decomposition will take place with resulting formation of free carbon, thus increasing the free carbon content of the pitch. Itisthus possible, by recirculation of the pitch and by regulating the spraying or agitation in the collector main so that the itch is kept in contact with the hot gases or a suiicient time to raise its temperature to the decomposition temperature, to decompose or crack greater or less amount of the pitch and/0r oil constituents and to, produce a corresponding amount of free carbon in the product.

In addition to producing pitches having differentproperties `and characteristics, the present invention permits the production of dstillates from tar or tar fractions or oils. Consequently it can be employed to distill a dirty oil or an oil contaminated with tar or pitch to produce a cleaner distillate oil'therefrom and a pitch residue. In systems where 'separate collector mains are employed each collector main may be supplied with a different material, for example, one may distill tar in the manner described and another may distill a mixture of oils for the separation of the dii'erent oil constituents therefrom.

The gases escaping from the separate collector main operated in the manner hereinbefore described contain considerable quantities of vapors or oils derived from the distillation of the tar or oil therein. The gases,`

being still at a relatively high temperature 1n order that the oils maybe retained in vapor form and thus separated from the pitch, may be subjected to any subs uent .desirable treatment for the urpose o effecting the separation of the oi in fractions. Thus, the gases may be conveyed through 'a series of fractional condensers, each adapted to reduce the temperature of the gases to a definite point at which a' desired fraction of the oil will condense and separate and can be withdrawn as a product of the operation. By providing a suitable number of condensers operated under regulated conditions to accomplish the desired purpose it is possible to obtain the oil in fractions having definite s characteristics and-qualities to meet the conditions imposed by the market for such oils.

The ap aratus ofthe present invention is adapted or thedistillation of tar and oils generally and the recovery' of distillates by the utlization of the hot coke-ovengases by bringing the tar or oil into direct contact therewith. The invention will be -further illustrated by the following more detailed description which should be read with the accompanying drawings snowing apparatus embodying the invention, but it is intended and will be understood that the invention is not limited to specific details of the apparatus as illustrated in the drawings, which Fig. 1 is a plan view of eolie oven illustrating one application of the invention thereto;

Fig. 2 is an end elevation, partially in section, of the structure illustrated in 1;

Fig. 3 is an enlarged sectional view of the short collector main; and

Fig. 4 is a view similar to Fig. 3 illustrating a `tatin means in the collector main.

-Referring to igs'l and 2 ofthe drawings, 5 indicates a battery of. colte ovens having individual uptake pipes and goose-necks 6 which connect the ovens with a collector main 7 The latter may be of any usual form and construction and is designed to receive all -of the gases from the individual coke ovens equipped with the usual spray nozzles to permit the introduction of ammonia liquor, or ammonia liquor and tar, for the purpose of cooling the gases and flushing the tar which is thrown down in the collector` main therefrom. The tar and ammonia liquor pass from the centre box to the cross-over main and may be withdrawn and delivered to a decanter 13 in which the ammonia liquor is separated from the .tar and utilized as de'- sired. The tar from the decanter may be accumulated in a tank 14 and delivered therefrom to the distilling apparatus as hereinafter described.

The tarry oils which separate in the condensers may be delivered to a decanter 15 and separated therein from ammonia liquor which can be utilized as desired. The oils may be added to the tar in the tank 14 or be treated separately. The apparatus as hereinbefore described includes the equipment provided usually in coke-oven plants and it is designed to be operated in the usual manner to separate tar and oils from the coke-oven gases.

According to one adaptation of the present invention the coke oven will be provided with a separate collector main 16 which may be disposed at any convenient place contiguous to the ovens but is preferably supported above and at the rear thereof and is connected to a number of the ovens by separate uptake pipes and goose-necks 17. Suit-able valves will. be provided in the uptake pipes to permit direction of the gases from the seiected ovens into the large collector main or into the short collector main as desired. When the latter is used for distillation the gases from these ovens will be diverted from the large collector main into which they will otherwise flow. The goose-necks 17 and separate collector main 16-are provided with spray nozzles 18 to permit the introduction of tar or oil as a spray to the separate collector main so that the tar or oil will be mingled-'intimately with the hot coke-oven gases flowing therethrough. The tar may be delivered to the sprays from the tank 1li through a pipe 19 by a pump 20. Tar may be supplied also through the pipe 19 and a branch pipe 9.1 to the end of the separate collector main `for the purpose of maintaining a suiicient quantity of tar in the collector main to ensure proper dashing of the pitch therefrom. To permit recirculation of the pitch in the collector main an outlet pipe 22 may be connected to a pump 23 which can deliver the pitch to the main through a pipe 24. By manipulating the valves a portion of the pitch can be sent through the pipe Q1 to the sprays. All or a portion of the pitch can thus be recirculated as desired and that por tion which is not recirculated can be withdrawn through a pipe 25 and delivered to a tank 26.

Referring to Fig. a of the drawings, the separate collector main may be provided, as a substitute for or auxiliary to the spray nozzles as hereinbefore described, with agitating means. Such means may comprise a shaft 30 extending through the collector main and carrying a number of paddles 31 thereon. By the application of power from any suitable source the shaft may be rotated at a suflicient speed to ensure the thorough agitation of the tar or pitch in the collector main and the throwing of particles of the tar or pitch into the stream of coke-oven gases passing therethrough. Such agitation will edect the desired intimate contact between the tar or. pitch and the coke-oven gases and consequently will permit effective distillation of t 1e tar or pitch and the production of vapor consisting of the vaporizable oils which can be condensed subsequently in the manner hereinafter described.

The distillation of the tar or oil in the separate collector main results in the enrichment of the normal gases by the volatile constituents of the tar or oil. These gases are withdrawn through a cross-over main 27 in which a series of fractional condensers 28 may be disposed for the purpose of progressively cooling the gases and vapors to temperatures at which the desired fractions of the oil will condense and separate so that these fractions can be withdrawn as separate products. The gases which remain after condensation in the iractional condensers may be delivered through a pipe 29 to the exhauster ll and thus mingled with the other gases produced by the co e-oven battery after separation of the tar and oils from these gases.

rlhe arrangement as described permits the operation of the coke oven in the usual man#4 ner and the utilization of a portion of the heat in the hot coke-oven gases for the purpose of distilling tar derived from 'the gases issuing from the other ovens of the battery or tar from other sources. The apparatus as described, including a separate collector main or mains, is particularly useful where the quantity of tar to be distilled is relatively limited and insuiiicient to permit the distillation operation to be conducted with all of the gases from the battery or even those delivered normally to one collector main. lt can be utilized, therefore, at isolated coke-oven plants where a single battery of coke ovens is operated and where the quantity of tar obtainable from other sources is relatively limited. lt permits the production of pitch having the desired characteristics and the recovery of valuable oils from the tar in a simple, ellective and economical manner.

The advantages of the invention have been A set forth in some detail and the preferred embodiments have been described. lt is to be understood, however, that various changes may be made in the form and arrangement of the apparatus without departing from the invention or sacrificing the advantages enumerated or any other advantageous results which may be accomplished by the application of the principles set forth.

l. An improved ly-product recovery system for coal distillation plants having a considerable number of coal distillation ovens, comprising at least one collector main and condensing system for collecting the gases from a greater part of the ovens and for cooling the same to separate tar therefrom, at least one still each connected to a plurality of ovens comprising a small proportion of the ovens and adapted for the passage of the hot coal distillation gases therethrough, means for bringing the tar so separated into intimate contact with such gases while at a high temperature and for eecting intimate contact of the tar with the gases whereby rapid distillation of the ytar can be eected, condensing means for condensing the distillate oils from the gases employed for such distillation, and means for mixing the gases after such condensation with the gases from the collector mains and condensers first mentioned so that the total' admixed ases can be further purified by the same puriigying operation.

2. In combination with ovens of a coke oven ovens to the collector main, means for passing gases from the collector main to the condenser, a'still, a second condenser, means for passing gases directly from a small plurality ot the said large number of ovens to the still, means for passing vapors 'from the still to the second condenser and means for mixing gases from the first-mentioned condenser with gases from the second condenser so that both gases can be urther purified by the same purifying operation.

3. ln combination with ovens of a coke oven battery, a collector main, a condenser, means for passingV gases :from the collector main to the condenser, a still, means tor introducing tar to the still, means within the still for bringing tar into intimate contact with gases therein, means *for withdrawing pitch from the still, a second condenser, means for passing vapors from the still to the second condenser, an uptake pipe at one end of each ci a large number of said ovens connecting these ovens with the collector main, means communicably connected with the opposite parts of each of a small plurality of said large number of ovens for passing gases directly from this small plurality of ovens to the still and means for mixing the gases from the rst-mentioned condenser with the gases from the second condenser so that the total admixed gases can be further purified by the same purifying operation.

ln testimony whereof I affix my signature.

STUART EARMELEEMILLER.

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