US1942375A - Method of coal and tar distillation - Google Patents

Description

s. P. MILLER 1,942,375

METHOD OF COAL AND TAR DISTILLATION Filed Deo. 1l, 1929 2 Sheets-Sheet l Jan. 2, 1934.

ATTORNEYS Jan. 2, 1934. 5 P MULLER- 1,942,375

METHOD OF COAL AND TAR DISTILLATION INVENTOR ATTORNEYS Patented an. 2, 1.9344

UNITED STATES METHOD F COAL AN) TAR DISTILLATION Stuart Parmelee Miller, Englewood, N. J., as-

signor to The Barrett Company, New York, N. Y., a corporation of New Jersey Application December 11,1929 Serial'No. 413,253

3 claims. (o1. 20H) This invention relates to thedistillation of the tar produced at a coke oven plant with production of' pitch and distillate oils, with subsequent coking oi' the pitch thus produced in one or more 5 .oi the coke ovens of a coke oven battery.

The process ofl this invention can be carried out at ordinary coke oven plants such as a Semet- Solvay coke oven plant or a Koppers coke oven plant, with no alteration to the plant or but slight alterations, 'and with the addition of a small amount of equipment. The tar recovered from the coke oven gases is distilled to pitch according to this invention, and the pitch produced is coked in one or more of th ovens of a coke oven battery. In this way,v the tar produced at the plant may be readily disposed of and the quantity of coke produced from a given amount of coal will be increased. The coke oven plant may be so operated that the only major products produced are coke, distillate oils, valuable fuel gases,

ammonia and light oils. 'Ihe disposal of tar at a coke oven plant has been handled in various ways in the past. Often tar has been burned as fuel, but this is undesirable in that tar contains valuable constituents, such as creosote oil, tar acids, etc.l 'Ihe tar can be distilled, but tar distillation lplants are not ordinarily associated with coke oven plants, and although methods ot coking pitch-are known, hitherto no method has been suggested for coking pitch in one or more of the ovens ot a coke oven battery with the saving in cost of equipment and operation which would result. By distilling tar at or near the coke oven plant, especially by distilling the tar by direct contact with the hot gases from `selected ovens of the plant, and coking the pitch produced in one or more of the ovens of a-battery, a high yield of oils may be obtained and added coke produced at the coke oven plant.

According to this invention, the tar recovered from the coke oven gases is distilled to pitch and the pitch is charged to one or more of the ovens oi' the coke oven plant. The ovens to which the pitch is charged are heated by the same equipment employed for heating the balance oi' the ovens oi the battery in which coal is coked. The vapors from the oven or ovens in which pitch is coked may be condensed in the condensing system provided for the treatment oi the gases coming from the coke ovens in which coal is coked, or if desired, special condensing means may be employed. The pusher provided i'orv removing the coke from the coke ovens may bel used for pushing the coke resulting from the coking of the 66 pitch, and the Acoke 'car and quenching system tarry oils from the condensers may be distilled invention, where the pitch produced is to be conemployed for treating the coke from the ovens charged with coal maybe employed for handling and quenching the coke resulting from the coking of the pitch. When pitch is coked at a coke oven plant, there is considerable economy in thus no utilizing equipment provided for the handling of the coke produced from coal in the balance of the ovens, and at the same time producing a high grade of metallurgical pitch coke of low ash and sulfur content and high B. t. u. value.

According to this invention, coke oven gases may be treated in the usual way for the removal oi tar. Any suitable means for cooling the gases may be employed. Either the heavy vtar which, separates from coke oven gases on cooling in the 7- collector main or the lighter tar which separates from the gases in the condensers may alone be distilled to pitch and the pitch thus obtained convetted to coke, or total tar comprising both heavy tar from the collector main' and lighter tar or u to pitch and the-pitch converted to coke, according to this invention.

A coke oven battery of, i'or example, 60 ovens, may be operated as a unit or where a number of so batteries are located at the same coke oven plant, the pitch resulting from the distillation of all of the tar trom the various batteries may be distilled in a number 'of the ovens o! onevbattery.

The tar may be distilled to pitch by any suitable method. The'tar may be distilled to pitch in al pipe coil still and vacuum distillationmay be employed toadvantage to produce a high melting point pitch. Steam distillation may be used to distill the tar to pitch. -It is advantageous to produce a high melting point pitch so that roaming of the pitchin. the oven is eliminated or reduced to a minimum.

According to a preferred method of distillation in whichpitch of high melting point is'produced and a high yield ot oils-is obtained, tar in the form o! a line intense spray is sprayed into hot` coke oven gases. Such a method oi producing pitch of high melting point is particularly suited for use in connection with the process 'of this 10 verted to coke at the coke oven plant. The hot coke oven gases from several of theovens are separately collected and passed through a stilly andthetarisdistilledbybeingsprsyedintothese hot gases. In such a still, using thegases from -iour to six ovens, it is possible ,to ordinary coke oven tar at a rato sumcientito produce the amount oi-pitch which can be distilled in an ordinary coke oven. It the pitch is coked in n0 an oven on an operating cycle of about to 22 hours, one still, utilizing the heat of four to six ovens, can produce `siiiillcient high melting point pitch to maintain one oven in continuous operation. Such a system can operate on a basis of converting about four million gallons of tar per year to pitch and then coke. It is to be understood that because the quality and the quantity of the tar produced at different plants, and even at the same plant under different operating conditions, varies, and because-they amount of heat contained in the gases from asingle oven varies, depending upon the quality of coal employed, the length ofthe coking cycle, etc., therefore. gures such as the above given in connection with such a system, can be only approximations.

into a coke` oven in liquid form, to be converted to coke, or it maybe chilled and solidified before being charged to the oven. When charged to the oven in liquid form, the pitch may be charged in a continuous stream and pitch already charged to the oven will be coked whilefresh pitch is being added to the oven. As the pitch in the oven is distilled and coked, more pitch is added to the oven and the coke formed inthe oven builds up until the entire mass of pitch is coked. In such a coking operation, the temperature, quantity and amount of gases leaving the oven is more or less uniform throughout the greater portion of the coking operation. 1

Instead of charging the pitch to the oven continuously, the oven may be charged intermittently. The pitch may be charged to the oven in four portions, for example, by admitting a fourth of the total charge of pitch to the oven at each charging operation, and converting the pitch in the oven after each charging operation to coke or semi-coke before charging more pitch into the oven. When the coking is carried on in this manner, the temperature, amount and composition of the vapors coming from the oven in which the pitch is coked, will vary. Where several ovens are vemployed for the coking of pitch,

. the ovens may be charged intermittently lin this manner but the charge may be so regulated that by combining the vapors from the several ovens a vapor stream of substantially uniform tempera-- ture,l composition and amount may be obtained.

'I'he vapors coming from the oven inwhich the pitch is coked may be treated in any one of several ways according to this inventio They may be collected and cooled in a condensing system entirely separate from the condensing sysc tem employed for vcooling the coal distillation gases, or they lmay be collected and cooled in admixture with the coal distillation gases.

The hot gases and vapors from the ovens in which the pitch is coked may be employed for the distillation of tar by bringing the tar into direct contact with them. Methods of distilling pitch in which a gas and vapor stream of substantially uniform temperature and composition is maintained for a prolonged period of time, adapt themselves to such distillation of tar more readily than a system in which the amount and temperature, etc. of the gases varies considerabl over a short period of time.

provided for collecting the coal distillation gases and vapors from those ovens in which coal is coked', and the combined gases and vapors are partially cooled in the collector main and further cooled in the condensers provided for the treatment of the coal distillation gases. The tar which separates from the gases on cooling is a combined tar and on distilling this tar to pitch of high melting point, an outlet for all of the tar produced at the plant is provided, and the pitch thus obtained may be coked so that the only products of such an operationvare coke, clean oils and gases.

The tar formed by cooling the vapors from the coking of pitch differs from ordinary coke oven tar. It contains less lower boiling constituents than ordinary c ke oven tar and contains a relatively large am unt of high boiling constituents including greasy and resinous compounds which nection with the accompanying drawings and more particularly with the operation of a Semet- Solvay coke oven battery with distillation of tar by direct contact with the hot coke oven gases from several of the ovens of the battery, but it is intended and is to be understood that the in vention is not limited thereto.

In the drawings:

l isa plan view of a coke oven battery equipped for carrying out this invention;

Fig. 2 is an elevation showing the tar still with a pitch feed to the two ovens at the end of the coke oven block; and

Fig. 3 is a section on the line 3-3 of Fig. 2.

The ovens of the coke oven battery V5 connect in the `usual way with the collector main 6 through uptake pipes 7. The ovens are heated in the usual manner as by heating nues within the separating walls. In the drawings the ovens are shown as being provided with horizontal heating dues 'I'. Means is provided for spraying the gases in the uptake pipes and in the collector main with ammonia liquor from the line 8. The v are collected in the storage tanks 12v and ammonia liquor is separately collected in ammonia liquor storage tanks. An exhauster 13 is provided for drawing the gases through the system.

The two ovens 15 and 16 located at the end of the'coke oven battery adjacent to the pinion wall 11 are `connected through the usual uptake pipes 'l with the collector main 6. Tar from the gases coming oiI from the ovens 15 and 16 is distilledwith tar from the coal distillation gases coming from the other ovens. The tar and ammonia liquor are drawn oil of the collector main at the end of the ovenadjacent to the pinion wall to the decanter 18. The heavy tar and ammonia liquor are separately drawn oilin th storage tanks 19 and 20. f

, Either the tarry oil from the tanks 12 or the heavier tar from the tanks 19, or a blend of both of thesetars may be distilled awarding to this invention and tar from the two end coke ovens and 16 may be blended with this tar for distilla tion in the still described below. Any tar producedl in connection with the operation of a gas producer or water gas set employed .for making gas for heating the ovens, may be added to this tar to be distilled in the still where desirable. l,

The tar still is indicated at 25. It connects through the' hot gas header 26 with uptake pipes '27 on a number of the ovens, preferably those adjoining the ovens 15 and 16 in which pitch is coked. By a proper manipulation of valves in the uptake pipes 27 and the uptake pipes 7 on these same ovens, the hot gases from these ovens may be diverted either to thecollector main 6 or through the'hot gas header 26 into the still 25.

Inthestillisaroll28. Itisadaptedtobe driven at a high speed, for example, 900 to 1200 R. P.. M. by the motor 29. Rapid rotation of this roll throws a fine intense spray of tar into the hot gases, thereby exposing a large surface of the tar to the distilling eiiect of the hot gases whereby distillation is rapidly and eiilciently eifected without any considerable decomposition of the tar. The fine intense spray of tar simultaneously scrubs the gases, removing entrained impurities present' in the gases. Ihe hot gases leave the still enriched in oil vapors and substantially free from entrained impurities.l 'lhey leave the still through the tower 25'. The tar to be distilled is supplied to this tower through the line 30. Baming means 31 and 32 are provided in the tower to remove entrained particles of tar spray from the gases. The tar lsprayed into the gases Dessins' up through the tower 25' is partially distilled and the semi-pitch produced is supplied through the line 33 to the end of the tar stili at which the hot gases enter. In the still 25, the semi-pitch is distilled to pitch of high melting point. This pitch is drawn ci! -from the still through the coke trap 34 and the leveling `arm 35. The leveling arm 35 has been shown as an open-ended pipe through vwhich the pitch flows into the pitch tank 44. The pitch is advantageously distilled to a high melting point, for example, 400 F. or higher.

The'hot gases and vapors from the tower 25' pass through the main 36 to a heat interchanger 37 in which they, are brought into indirect heat interchange relation with the tar to be distilled. The tar is thus preheated and heat economy -is effected. Heavy oils are separated from the gases and these are collected in-the storage tank 38. The gases then pass to a further condenser which may be a direct condenser 39 in which the gases are sprayed with water or ammonia liquor from the line 40. This condenser drains into the decanter 41 and separate means are provided at 42 and 43 for collecting the ammonia liquor and lighter oils.

'Ihe high melting point pitch may be supplied directly from the still to the ovens, or it may be rst cooled and soliditled and supplied to the ovens in solid form or, according to thepreferred Although two ovens 15 and 16 are shown equipped for coking pitch, but one oven may be employed at one time and the other oven may be held in reserve so that when it is necessary to shut one of the ovens down for repairs or for other reasons, the other oven may be employed for the coking of pitch. In the meantime, it may be employed for the distillation of coal. EachY of ther ovens 15 and 16 is provided with a' pitch feed 45 which is connected with the pitch storage tank 44 by the heavily insulated line 46. Suitable valve means indicatedat 47 is provided for controlling the iiow of pitch through this line, and

means for blowing the line with steam after use is advantageously provided. Ihe pitch feeds are removably mounted when they enter the oven .through an oven door as shown; When pitch is to be added to the ovens in a continuous manner with continuous coking of the pitch and continuous production of coke, each oven is advantageously provided with several pitch feeds which may be llocated in the top of the oven or at any suitable point in the oven.

The arrangement here shown is particularly adapted for an operation in' which va quarter of 100 the total charge of pitch is charged to the oven at each charging operation, and there are four charging operations during each coking cycle. The pitch is charged intermittently, and before any additional pitch is added, the pitch already present in the oven is converted to coke or semicoke. l

After the full charge has been added'to the ovens and the coking operation is completed, the charge of coke in the ovens is removed in any suitable manner. The pusher which operates on tracks (not shown) under the cross-over main and which is employed for pushing the coke resulting from the distillation of co'al in the balance of the ovens of the battery, may be employed for pushing the coke from these ovens 15 and 16. The coke car. which operates on tracks atthe opposite side of the battery may be-employed for receiving the coke as it is pushed from the ovens 15 and 16. The coke quenching equip- 120 ment-employed for cooling the coke produced from the coal may be employed for cooling the pitch coke. In this way the cost of the original equipment is ikept at a minimum /by employing the same means for handling the coke produced from coal and the coke produced from pitch. The tar-distilling means shown yields a high percentage of distillate, -and pitch of high melti ing point is produced. By the combined equipment here shown, a high yield of distillate is ob- 133- tained and the battery may be so operated that the only maior products of the operation are coke, distillate oils, and gas and light oil.

I claim: v l

1. The method of operatingv a coke-oven bat- 135 tery involving a series of coking chambers separated by heating walls, which comprises coking coal in one portion of said ovens and coking pitch in a second portion thereof, withdrawing hot gases resulting. from the coking of coal and 14,1 cooling them to separate tar, passing the tar in heat yexchange Vrelation with the hot gases from a portion of the ovens of the battery whereby said tar is distilled to pitch, and introducing said pitch into said second portion of the ovens of the battery and coking it therein.

2. The method of operating a coke-oven battery -which comprises coking coal in a portion of the ovens of the battery to form a coke from coal, coking pitch in another portion of the ovens -to separately form pitch-coke, withdrawing thel vhot gases resulting from the coking of the coal coking pitch in another portion thereof, withdrawing hot gases resulting from the coking of the coal and hot gases resulting from the coking of the pitch,combining these gases and cooling them to separate tar. intensely spraying into the hot gases from a minor portion of the ovens of the battery the tar thus separated whereby said tar is distilled to pitch and whereby entrained tar particles are scrubbed from said gases, cooling the gases to condense clean oils, and introducing said pitch into said other portion of the ovens of the battery and coking it therein.l

S. P. MILLER.

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