US1191943A - Process of making coke. - Google Patents

Description

WA BUHLtR & 6.1. EMERSON PROCESS 0F MAKiNG COKE.

AVPLICATION fILEU NOM.7

Puvutd July Q5. 19145.

4 SHEETS#SHEET.1.

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APPucmoN mw Nov. 1.1914.

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HENRY W. BUHLER AN D CHARLES J. EMERSON, OF BOSTON, MASSACHUSETTS, ASSIGN- OBS 0F SEVEN-EIGHTHS TO GEORGE D. HASKELL, OF BOSTON, MASSACHSETTS.

PROCESS OF MAKING COKE.

Specification of Letters Patent.

Patenten July 25, 191e.

Application led November 7, 1914. Serial No. 870,809.

Yctl which the following is a specification.

This invention relates to certain improvements on the old and wel] known process of making coke in. 'what are known as wasting ovens.,l of wh'mh the so-called beehive oven is the oldest and best known typeA lts .purpose and effect is ',to materialiy shorten the time consumed in the coking process, to recover the best portionI of the by--l'iroducts, such as tar, ammonia, etc.,without requiring the use of any costly arrangement of liues subjected to temperatures so highas to be rapidly destructive thereof, and also to produce a good quality of coke by direct and even application of the .heat employed.

In the simple proc/ess heretofore generally used with the wasting ovens, the coal is placed in an oven having a trunnel opening in the top for escape of gases of combustion, and doors provided with openings for the admission of regulated quantities ot air. The coal is spread upon the floor of the oven in an evenllayer. In usual practice a layer of an initial thickness of about 32 inches is employed. This is lighted from the top, regulated quantities of air are admitted thrdugh the'doors to support combustion of the gases distilled from the charge, and the gases of combustion escape through the trunnel head. The heat of the oven walls, retained from previous operations, o r conducted from adjacent ovens in similar operation. produces this initial distillation and combustion. The direct heat of the gases burning in the oven continues and completes the distillation and coking operation. The products of the distilling process are mainly hydrocarbon gases.

. the only useful product realized from the .the coke produced.

The carbona-k ceous vrcslilue of the coal cokes and formsv tion.,\vhich layer of coke will interfere with the transmission ot' heat to, 0r liberation of gas from, this bottom layer of the charge. Consequently, the gases least in quantity and poorest in quality are supplied to the combastion zone in the top of the oven, and the least amount of heat generated there, at

'the very time when the greatest heat is needed to penetrate the overlying coke and complete the distillation in the l'owermoststratum .ofthe charge. This is what prolongs the operation to -18 hours or more in this old type of oven. One great advantage of this simple process is 'the even character of The coking operation being progressive, .from the top downward, there are no breaks or planes of demarcation in the grain or formation ot' the coke.

, While the simple type of wasting oven above described still occupies the. principal field, .at least in this country, numerous more elaborate types of ovens have been designed and used for shortening the period of operation and recovering the by-products0 from the ,cases of distillation. These ovens .have more or less elaborate systems of flues in the walls and under the doors thereof. The

distilled from the charge are notburned in the oven, in contact with the coal and coke, but are drawn olii, as distilled, passed through suitable condensing apparatus which extracts the by-products, and the purified, fixed'gases are then led back and burned in the flue system, with admixture of air. The heat so generated must pass through the Hue and ovenv walls, by conduction, before it reaches the charge in the oven.

' To secure the necessary heat inthe oven a much higher temperature must be created in. the flues. Hence a costly construction of .highly refractory materials is required, and,

even with this deterioration is rapid in the standard by-product oven, `so that repairs, together with interest on large initial cost, creates a large item of expense. Fur` thermore, the coke produced' by such conducted heat is not as good for some purposes as that produced by the directlyapplied. heat of the. old wasting process, and is apt to show breaks, or planes of demarcation, whore the coking actions starting from op-v posite 'sides or surfaces of the charge, meet in the interior thereof, thus destroying the even grain, or homogeneous character of the product.

The present invention combines certain of the features of advantage of both of the ucts therefrom. The purified gases emerging from the scrubbers, etc., are returned to be burned in an oven, over the charge therein, during the later stage of the coking operation, together with the residual gases distilled from the lower strata of the charge during that final stage. Thus an intense and easily controllable heat is generated during the later stage 0f the coking operation Which greatly shortens the'time consumed. This heat is applied directly'to the charge, combustion taking place in the oven, over the charge, as in the old wasting process. The coking action is progressive from the top downward, and the same homogeneous product results as in the wasting oven. (ln the other hand, the major portion of the by-products are recovered. There `being no combustion in the oven during the first stage the gases distilled pass to the condensing apparatus with all their normal content of tar, ammonia, etc., undisturbed. The richest gases are the most vola-tile, and these are given oit during this preliminary stage. All this is'accomplished with the old, cheap' and durable form ofwasting oven, and the proeess can be applied to the thousands of such ovens now in use by adding a condensing ap|m 1-at11s, and the necessary piping, with perhaps a blower', and certain re-arrangements of the air inlets. Y

The simplest form of apparatus for carrying out this improved process involves the use of a single oven and a gasometer in *which the gases may be stored until the time for returning them to the ovenarrivcs. In commercial use, however, a Series of ovens would be built together, and certain of these would be distilling gases while others were burning them, and vice versa, so that the intermediate storage ofv gases in any large quantity would not be necessary.

The accompanying four sheets of drawing illustrate one form of apparatus arranged to carry out the improved process or method lherein referred to, in the best manner at -present known to us.

Figure 1 is a sideelevation of an apparatus with parts broken away, showing the general arrangement of a set of two ovens and connections for carrying out our process of coke making. Fig. 2 is. a longitudinal cross section of one oven taken on line 2-'2 of Fig. 1, but on an enlarged scale. Fig. 3 is a vertical cross section on line 34-3 of Fig. 2, Showing both ovens, and Fig. 4 is a horizontal section of one oven on line 4-4 of Fig. 2.

Throughout the drawings like reference standard type. In practice a long series of such ovens would be built closely together, to interchange heat by conduction. These ovens are of rectangular 'horizontal cross section with arched roofs 4, 104, rising to peaks midway of the length of each. At the peaks of the roofs are the usual trunnel heads, one of which is shown at 102, each having a removable cover 103, as shown in Fig. 2. At each end of each oven are doors 5, 105, having openingssuch as 106,` (Figs. 2 and 4) through which pass nozzles for air jets 7,1107, and gas jets 23, 123. Similar air nozzles 8, 108, and gas nozzles 24, 124, may be inserted through openings inthe oven roofs and side walls. v

Each oven has one or more gas outlets.A

Preferably these are in the roof, as shown at 9, 109, though they might be placed at other points. Each gasv outlet is controlled by a valve 10, 110, communicating withv hydraulic main 11. This main opens into an exhaust pipe 12, controlled `by valve 13, and leading to a series of washers, scrubbers, condense-rs, etc, 14, 14, of standard type. Some means, such as suction fan 15,

for accelerating the movement of the gases,

may be inserted in the circuit at a convenient point.

16, is a gasometer into which the purified gases may vbe led by pipe 17, when valve 18, is open.

15), is an outlet pipe from the gasometer controlled by valve 20. A` by-pass, o1' cutout pipe, 21, controlled by valve 22, connects pipes 17, and 19, outside of the gasometer, The gas outlet, or return pipe, 19, has a branch 25, communicating with gas nozzles 2l, 124. lin the oven walls, and another branch 33. to gas nozzles 23, 123, in the oven doors. Each connection to a gas nozzle is controlled by a valve 26, or 126. Any convcnient form of damper for controlling the ,l

inflow of air by natural draft may be used. W c have shown cup-shaped, sliding dampers 27, 127, having radial air inlets as Shown at 128 (see Figs. 2 and`4). i

' 38, represents a blower or air compressor discharging through pipe 37, to the air noz--A Each connection to an airl with the above described apparatus ai? follows: Assuming only one oven as'101, o be used. the-chargejof cokingcalis introduced and leveled ofil in the usualggnanner arid the doors 105, placed n`positi9n` r`he'heat mil the oven roof and walls carried over from a previous operation would usually be suflicient to start the distillation of gases in quantity from the. charge. as soon as the moisture contained in the coal is vaporized. It necessary the further heating of the oven may be accomplished by opening the dampers 127.1)y pulling them outwardly to admit air through some of the holes` 12a. which will cause the gases initially distilled to burn. until the desired temperature is se curcd in the oven. The cover 102i. is left oil' the trunnel head so that the gases o1' rombustion may escape. This necessarj.' preheating may also be accomplishwl wholly or in part 'uy burning some of the gases stored in gasometer 11i. in the oren before the charge is introduced. ll'hcn the distillation is under way in the oven at a rate sutfi cit-nt to warrant collection o1 the gases tor treatment, the trimml head cmcr 117, is placed in position, thi` danipers f2?. are shoved in and all other means ot access of air to the men interior are closed. and the` \alves llt). and 13. are opened. The faullfi. bring set in operation. the gases o1' distilia; tion are drawn through outlct 105). and forced through scruhbers and condensers 14. 1-1, to gasometer 1(i.--\al\c lia. ireing open. and \alvcs 21h and itl. being l-ti.-;cd. This operation is continued as long: as there is a ropious tion' of gases from the oven 10i. hen the Iguantiti of gasc.t distilled falls otl'. or their eouteut of hjnproilurts diminishes. the #.iiws ili. lll ford l5 -1 c close-'l and the valve 12"?. is opened. "i ir purified giurtS uiimiuluted in the gusoun-t?! lli. Ill-:ii pass through pipe 1E). and branches zi. and 33. to gas nova/.lesv 12E. and 1;".` in the doors' andsiden'allsof theoven. .\ir which mayor may not be preheated in is also admitted cit her through the dampcrs 127. or air no3/.2410s 107. and 1118. or all of these inlets. Cover 10.3. being removed. the gases introduced into the oven, mixed with those still being distilled ofi' from the charge, barn at a regulated rate. generating all the heat necessary to rapidly complete. the colting ollieration. ll'hen the entire charge is relied. the doors are opened. the colte* ro nuived, a new charge inserted, and the oporation repeated. hen batteries of ovens are employed, the initial operations ma \v be assumed as carried on in over. 101. :ind its fellows, as'above described, but when the second, or combustion stage is reached. the first, or distillation stage is also begun in oven 1. and its fellows. The gases so generated in over l, may, after purificationff hg led directly to men 101, by opening by )ass alvc 22, and closing valves 1S, am :28. Thus the gases distilled in any one set of ovens durin the first, or distillation period, are burned in the other set of ovens. with the residual gases there distilled, during the any vfcll known way second or combustion period therein occurring. The operations alternate. Thus, while one set of ovens are losing heat through distillation of their contents without combustion. the deficiency is largely supplied by the excess heat conducted through the ivalls from the other set of ovens, sandwiched in between the members of the first set. in which latter set, combustion is going ou at a rapid rate. llvcn in this case, howcvcr. it is well to run the purified gases through the' gasometer. as it serves asa Compensating device` absorbing any momentary surplus. and giving it up again when there is a temporary deficit of gas.

As a result of the above described operations a charge of a given character and thickness of coal can he completely coked in about half the time that would be required in the old Wasting process. This is because tla-` heat is applied in a controllable manner to secure a maximum rate of gas distillation ai; all times. and in the most et'- ticient way. mainly lry combustion in the oven. where the celiing process is being carricd on. By this method the heat is transmitted directly to the roal also in the oven` or directly to the oven walls and roof, by which the greater portion is later given back again to the nut charge. while the lesser portion. which passes through the walls. is not lost` but given over to the ovens on either side. wht-rino combustion is going on .\s a further result the by-products are rwovcred from the richest gases of distillation. onlyY the poorer gases heilig burned in the oyen :is evolved. The use, ot' thin flue, walls. within which constant combustion must he maintained as in the standard byproduct oven. is avoided. and only thick, durable walls are employed. so that the burning out or choking up of elaborate system.;i of lines is not to be feared. 0f course, the process4 could be carried out with other forms of' men. the gases might he taken from and returned to the oven at points other than those shown in the drawings. and other modifications in, detail introduced without depaiting from the` principle of the invention. which comprises; drawing ott' and condensing the richest gases of distillation, without combustion in the oven. during the first period of each coking cycle. and then returning condensed gases to be burned with the final gases of distillation in the oven during the second period of the coking cycle.

Having. therefore. described our invention. we claim:

1, The method of coking coal and recov cring a portion of the lay-products therefrom. comprising the following steps: first, subjecting a body of coal to a partial coking operation by heating it in a closed oven sufciently to dis-til therefrom the more volastile gaaf under conditions preventing comlio bustion; second, extracting by-products from gases so distilled; third, completing the coking of a body of coal partially eoked by the above described first step by burning over it and in the saine oven gases purified by the above described second step.

2. The method of coking coal and recovering a portion of the by-products therefrom7 comprising the following steps: first` subjecting 'a body of coal to a partial coking operation by heating it in a closed oven suf'- ficiently to distil therefrom the more vola tile gases under conditions preventing couibustion; second, extracting by-products from gases so distilled and storing said gases; third, completing the cokng of' a body of coal partially coked by the above described first step by burning over it and in the same oven gases purified and stored by the above 'described second step.

3. The method of coking coal and recovering a portion of the by-products therefrom, comprising the following steps: first, subjecting a body of coal to a partial coking operation by heating it in a closed oven sufficiently to diStil therefrom the more volatile gases under conditions preventing combustion; second, extracting by-products from gases so distilled; third, completing the coking of a bod of coal partially coked by the above descriiied first step by burning over it and in the same oven gases purified bv the above described second step together with the residual gases distilled from the said body of coal in this final stage of the coking operation.

4. The method of coking coal and recovering a portion of the by-produets therefrom which comprises the following steps: first, subjecting the coal in a suitable oven to heat sufficient to distil ofl` the more volatile gases under conditions preventing combustion thereof; Second, removing said distilled gases from the oven and extracting the b v-products therefrom; third, returning the purified gases to the inte'rior of the oven at a later stage` and burning them, together with the residual gases distilled from the charge, above said charge. until the coking operation is completed.

The method of' coking coal and recov ering a portion of the by-products therefrom, comprising the following steps: first, subjecting a body of' coal to a partial coking operation by heating it in a closed oven sufficiently to distil therefrom the more vola tile gases under conditions preventing combustion; second, extracting byproducts from gases so distilled; third, completing the coking of a body of' coal partially coked by the above described first step, by discharging simultaneously into the oven containing it, gases purified by the above described second step and air under pressure and burning in said oven the combustible mixture so formed.

HENRY W. BUHLER.. CHARLES J. EMERSON.

"itnesses 1 Y (leonor: D. HAsKicLii, FREDERICK M. LIN'roN.

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