US2167100A - Process of preliminary oxidation of caking coal with subsequent coking thereof - Google Patents

Description

July 25, 1939- P. J. M. BNEZECH 2,167,100

PROCESS OF PRELIMINARY OXIDATION OF CAKING' COAL WITH' SUBSEQUENT COKING 'I'IEREOFy I Filed FebY l2, 1957 2 Sheets-Sheet 1 NNN z a C QN .swab o@ c um H Vl/ mwN @NI .WSQN s !!-2-\-\\Mw i.-- H \U,....HHH. .|.HH...W\\M- @N .un -/NN ^N^N\1,. u.. @N xk l .IMHMHINUMHHMHHHIHH .n.wmh -i wmx JHHH-\ L. P. J. M. BNZECH July 25, 1939.

PROCESS OF PRELIMINARY OXIDATION OF CAKING COAL WITH SUBSEQUENT COKING THEREOF Filed Feb. l2, 1957 2 Sheets-Sheet 2 Patented July 25, 1939 PROCESS OF PRELIMINARY OXIDATION OF CAKING COAL WITH SUBSEQUENT COK- ING THEREOF Louis Philippe Joseph Marius Bnzech, Carmaux, Tarn, France, assignor, by mesne as signments, to Kappers Company, Pittsburgh, Pa., a corporation of Delaware Application February 12, 1937, Serial No. 125,392

In France February 14, 1936 1 Claim.

'Ihe present invention relates to the production of coke out of caking coals and more particularly to the preliminary preparation of such coals for subsequent carbonization at a distilla- 5 tion temperature of 550-1200 C. (measured in the coal charge of the chamber), in vertical, inclined or horizontal chamber ovens. The object of my invention is to provide such improvements,

high heaps or layers, and that the danger of suchheating` will increase, the longer the hot season and the higher the atmospheric ,temperature If the temperature exceeds theignition point of the coal, re nests will break out and finally, as the case may be, the whole coal mass will burn. It is also known, that caking coal, which during storage has undergone a comparatively low heating, looses its caking power.

It has now Ybeen lfound,tha.t the oxidation of caking coal can be"`conduc t'ed and limited by heating insuch a way, that the carbonization of the coal 'at-temperatures' between 550-'1200 C.

results inl a semi-coke, which is well flown, re-

sistant, dense, reactive and extremelyvhoinogeneous, without anyinert materia1s',"such as coke dust, lean coal, being adrnixed Ato the'caki'g co'al. In fact such cokes or semicok'e's, -made from `cak ingcoals' partially oxidized "t'o A 'ai' definite and limited degree, are' practicallyinoriolythic.v They 55 products, (semi-coke andcoke) asproduced in cokes' are, lmoreven-'fwell molten, fevenf 1n the 7 the manner described above, are considerably more reactive than those materials, which are obtained under similar distillation conditions, by

mixing the basic coal with other carbonaceous but inert, l. e. non-caking, substances.

On the other hand, under certain heating conditions the coking time of those coals, which were subjected to a suitably adjustedoxidation, is less than the coking time of a corresponding mixture of raw coal and inert substances, so that the capacity of the" battery will be increased, pro- -vided of course, that other operating conditions are unchanged. y

The process according to my present invention consists principally in that the total quantity of the caking coal, to be treated, is subjected previously to the carbonization to a controlled heat treatment for oxidation.

This fundamental idea of the invention is pref# erably accomplished by carrying ont the oxidizingl heat treatment to the desired extent within a tower-like storage bunker, in Whichthe coal is Vkept at a raised temperature below the softening point of the coal, in the presence ofv oxidizing gases such asair. The coal remainsfora deflnite regulatable time in this bunker. By altering the time forthe storage-.ofthe coal in this bunker, the degree of oxidation `is controlled. The period for the storage of `.the coal, in the bunker naturally depends upon the properties of the coal, upon the re-storages and conversions,

. which-'are taken up by the: coal in the pretreatment before it isv stored in the coal .bunker x and also upon the `temperature prevailing in the coal bunker. l L

- The'. coal treatment bunker can be heateds'in any desiredrway.v A ldlrect heating is not vnecessary if the bunker' is charged withA a h'ot: coal. gThe walls of :thecoal'bunker may beflined with aheat insulatingmateria'l Furtherpbjects andfadvantages ofi-my inven- 1 fti'o'n will be in part 'obvlous' andi-npart'specically i pointed out in the..'desc'rlptionzy hereinafter cony'companyingdrawings;A discloses afpreferred em- "bodimentlthereofs Suchfeiiibodimentrhowever' is toy considered as fillustra'tivef'of: the principles extractor 3 to the feeding pipe 4 of a drying tained, whiclftakenfin condunctin with-z the ac-g;vv

The drawings illustrate 'two'. diierent..l-modesh-` drum 5. In conjunction with the raw coal, the hot gases are introduced into the upper end of, the drying drum 5, the hot gases being produced by the combustion of gas and air in a gas burner 6, situated in a chamber 8, which is formed by the refractory brickwork 1. The/space 8 surrounds the feeding end of the drying drum. The drying drum is fltted with ball-races 9, revolving on bearings I0. 'I'he lower end of the drum 5 reaches into a casing II, where thev separation of heating gases and vapours from the largest amount of drying coal takes place. The joints, between the casing II and the drum 5, and between the furnace chamber 6 and the drum, need not be sealed, a close fit sumcing or, if desired, a packing gland of any usual or well known construction for the purpose may be provided for such joints. The vapours and gases from the. casing II flow to a dust separator I2, from which they are withdrawn through a pipeline- I3, by means of a blower I4, into the chimney I5. 'Ihe coal precipitated in the dust separator I2 runs through the pipe I6 into the exit I1.of the casing II, and meets there with the other dry coal.

'I'he dry coal is delivered through a sluice III` onto a bucket elevator I9, by means of which it is conveyed into the charging opening of a tower-like holder 2|, which is sub-divided by a middle partition wall 22 into two compartments 23 and 24. Special discharging equipment, 25 and 26 respectively, is provided for each bunker. The discharging devices and 26 are arranged in such a way, that a coal charging car 21 of a horizontal chamber oven battery 28 can travel underneath them.

As described above, the coal is stored fora certain period at a fixed temperature in the treatment tower 2|. that is aging in the treatment tower 2l, to the desired temperature, quite a number of suitably staggered heating pipes 29 are provided in the coal tower. A controlled quantity of` hot waste gases is supplied to the heating pipes by means of a `blower 30 from the waste gas channel 3| of the coke oven battery, through a pipeline 32. If the inlet of the pipes 29 is suitably dimensioned, the heating media are uniformly distributed inthe ldesired way through the heating pipes. On the other side, the heating pipes open into a waste-gas collecting pipe 33, from which they escape into the chimney 34.

'I'he process for carrying out the invention according to Figure 2 differsin principle from the plant shown in Figure l, in that the coal is not heated in the treatment tower itself, but is charged in hot condition into the treatment tower. The raw coal 40 runs from the raw coal bunker 4I through a discharge arrangement 42, into the drying drum 43, which is supplied with hot gases, being delivered through the pipeline 44. A contrivance by which the heating gases and vapours are separated from the coal, is fitted at the outlet of the drying 'drum 43, similar to the apparatus of Figure 1. 'Ihe dried coal is then fed through the sluice into a set of drums, consisting of two revolving furnace drums, 46 and 41. 'I'he set of drums is arranged in an oven chamber, formed by the refractory brickwork 46. The oven chamber 48 is heated by means of gas-air burners, which are supplied with heating gas through the pipeline 49. 'I'he waste gases are withdrawn from the oven chamber 48 through pipeline 50.

The coal charged into the upper revolving furnace drum 46 is warmed up and nally iiows In order to bring the coal through a connecting main 5I, arranged at the other end of the revolving furnace, into the lower revolving furnace drum 41, in which the coal is further heated up to the desired temperature. The heated coal leaves the set of drums through the pipeline 52, which is connected to the sluice 45 by means of an adjustable connecting pipeline 53, so that, if necessary, hot coal can be mixed with cold, dried coal and the temperature can be adjusted exactly corresponding to the coal. A mixer 54, holding the mixture of cold and hot coal, takes care of an intimate mixing of both media.

'I'he coal is delivered from the mixer 54 to a bucket elevator 55, by which the coal is conveyed into the inlet 56 of a coal bunker 59, comprising two compartments 51 and 59. Each compartment is connected to'a special discharge contrivance 60 and 6I. 'I'he Iarrangement of the coal treatment tower 59, similar to the design shown in Figure 1, is such, that the coal charging `car 62 of the oven battery 63 can immediately be driven underneath the outlets 60 and 6I.

The heat treatment of the coal in the apparatus as shown in Figure 2 is done in such a. way, that the coal at the outlet of the furnace 41 has reached a temperature as high as possible, but below the point at which the coal begins to soften. The coal temperature at this part of the plant is for instance 3D0-310 C., if a coal with about 26% `volatiles is to be dealt with, which is often the case in Southern France.

The coal remains in the treatment tower 59 at an increased temperature so long as may be necessary, until its cakeability is reduced to the must be seen to it, that the coal is uniformly moved within the treatment bunker from the top downwards.

The storing of coal in the compartments 51 and 58 takes about 120 hours. Under these clrcumstances, the fuel at the inlet into the treatment tower has for instance a temperature of l60 C. and when the coal is filled into the coal charging car, the temperature amounts to 13G-M10" C.

Cooling means may also be arranged in the treatment towers. in order to reduce the temperature of the coal charge in the tower, if necessary.

On account of the prolonged heat treatment, the coa-l is subjected in the pre-treatment plant to a partial oxidation, which begins already in the rotary furnace and which is continued in the treatment tower. In the latter, the oxidation is effected by means of oxygen in the air. which surrounds the coal particles and by the oxygen fixed in the coal. The control of the time for storing the coal in the treatment tower is done in such a way, that the coal at the exit of the treatment tower has the desired optimum cakeability.

If based upon dry coal, which for instance is produced if a pneumatic preparation of coal is provided for, it will be sufiicient to charge the coal regularly at a certain interval or continu-y ously into the treatment towers, which depends upon the properties of the coal, for instance upon the oxidation degree, the temperature and the time for storing the coal in the tower, i. e. those factors, which have an influence upon the cakeinstance into the drying drum 5 or 43, as illustrated on the drawings, collaborating with a suitable dust-extractor, the dry and slightly heated coal at a temperature of about 80-100" C. is methodically lled into the treatment towers, which as above described, are arranged at their exit with those contrivances, producing a uniform movement of coal through the tower.

I have now described my present invention on the lines of a preferred embodiment thereof, but my invention is not limited in all its aspects to the mode of carrying out as described and shown, since the invention may be variously embodied within the scope of the following claim.

I claim:

In a process for the production of coke and semi-coke from coking coal which previously to the carbonization thereof, had been subjected to a predetermined limited degree of oxidation to reduce the cakeability of the coal, the improvement comprising: storing the total quantity of coal to be coked in a downwardly moving towerlike bunker column thereof; oxidizing the coal during its storage with only the air normally entrained in the coal when charged into storage'by merely aging the coal in the bunker column, in the absence of direct contact with heating gas, and while being maintained at a temperature between 150-160 C. at the top of the column and 130 140 C. at its bottom, for the period of time, comprising at least several days, predetermined as being required for oxidizing of the coal by aging it with its entrained air to attain the required degree of oxidation before the coal is withdrawn at the bottom for carbonization; the coal to be oxidized being supplied at the top and the oxidized coal being withdrawn at the bottom of the bunker column regularly as required for the coking step; the aging being effected so that the coal introduced at the top is aged in passing to the bottom in itsprogressive descent through the column; and thereupon carbonizing the aged oxidized coal as it is withdrawn from the bottom of the bunker column.

Louis PHILIPPE JOSEPH MARIUS BNzEcH.

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