US2346991A - Coke oven - Google Patents

Description

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2 Sheets-Sheet 1 ATTORNEY lNvEN C14/u c. oTTo COKE OVEN Filed Mam zo, 1942 April 18, 1944.

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coxE ovm:

Filed March 2o. 1942 2 sheetsheet 2 /V "'j y INVENTOR CARL OTTO Patented Apr. 18, 1944 COKE OVEN Carl Otto, Manhasset, N. Y., assignor to Fuel Refining Corporation, New York, N. Y., a co1'- poration of Delaware Application March 20, 1942, Serial No. 435,481

7 Claims. (Cl. 202-I51) In heating horizontal coke ovens by the combustion Yof coke oven gas or other rich fuel gas in vertical iiues located at the sides of the coking chambers and provided with burners all located at the same level adjacent the coking chamber bottoms, difficulty has been experienced in distributing the heat with sufficient uniformity along the lengths of the flues, particularly when the iiues are as long as is required in large capacity modern ovens. To minimize such difculty, it has been proposed to mix products of combustion with the rich fuel gas supplied to the combustion flues, so as to elongate the flames formed above the burners and thereby reduce the local overheating adjacent the burners which is experienced when the flames are shorter.

The general object of the present invention is to provide improved means for thus diluting rich fuel gas supplied to the combustion ues of horizontal underred coke ovens. A primary and more specific object of the invention is to so form and dispose the fuel gas diluting means as to avoid interference with the operation of said means by dirt dropping down in the channels through which the diluted fuel gas is passed up to the heating flues. Another specic object cf the invention is to provide means operative to prevent the rich fuel gas diluting means from interfering with the heating of the ovens during periods in which the oven heating fuel is a lean gas. A further specific object of the invention is to provide simple and eiective means for continuously passing a small amount of atmospheric air into the channels through which the diluted fuel gas is intermittently passed up to the heating iues.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specication. For a better understanding of the invention, however, its advantages, and specific objects attained with its use, reference should be had to accompanying drawings and descriptive matter in which I have illustrated and described a preferred embodiment of the invention.

Of the drawings:

Fig. 1 is a, longitudinal section through a portion of a coke oven battery, when on the line Fig. 2 is a partial section on the une 2 2 of Fig. l;

Fig. 3 is a section taken similarly to Fig. 1 but on a larger scale and showing a Vportion only of the apparatus shown in Fig. 1;4

Fig. 4 is a section taken similarly to Fig. 2 but on a larger scale and showing a portion of only the apparatus shown in Fig. 2;

Fig. 5 is a section taken similarly to Fig. 3, illustrating a modification; and

Fig. 6 is a view similar to Fig. 4 illustrating a modification.

In the drawings, I have illustrated the use of the present invention in a horizontal coke oven battery of the well known crossover type, comprising side by side coking chambers A with interposed heating walls formed with vertical combustion flues B, and in which a series of crossover channels C extend over every alternate coking chamber A, each channel C connecting one or more heating flues B at one side to the directly juxtaposed flue or flues B at the opposite side lof the subjacent coking chamber. Beneath and parallel to the coking chambers and heating walls are pairs of regenerators D alternating with pairs of regenerators d. Each combustion flue B has its lower end connected by a conduit or channel E to one regenerator d. When the battery is heated with lean fuel gas the regenerators d are used in preheating that gas, while the regenerators D are used in preheating combustion air, but when the battery is heated with rich fuel gas, regenerators d as well as the regenerators D areused in preheating combustion air. A l

Beneath the different regenerators D and dare sole channels D and d', respectively, and at one or at both sides of the battery reversing valve means F/are provided for connecting each of the sole channels D to a waste heat'flue G leading to the stack not shown or to the atmosphere and for connecting each channel d' to the waste heat flue G during lperiods which alternate with periods in which said channel ci is connected either tothe atmosphere or to a lean gas supply pipe H, according as-the battery is operated with richer lean fuel gas. valve means F form no part of the present invention, and may be Aof well known form, they need not be further illustrated or referred to herein. n

In operationfwith rich fuel gas, the latter is passed into the lower end of each flue B during each period inwhich Vcombustion is being initiated in that iiue, throughv va corresponding rich gas supply channel I which extends downward from the flue through `the subjacent regenerator division or pillar wall, anclthrough ythe supporting deck` J, customarily formed of reenforced concrete, whichv supports the vcoke oven brick- Inasmuch as the reversing work and forms the roof of the subway space or basement JA of the coke oven battery. As shown, the lower portions of each channel I is lined by a metal tube K which extends downward from the underside of the deck J for a short distance and has its lower end normally closed by a cap or plug K accessible from the space JA for removal to permit the channel to be inspected and cleaned.

In accordance with the present invention coke Ioven gas or other rich fuel gas which does not require regenerative preheating is supplied to the lower portion of each channel I through a corresponding branch channel L formed in the deck member J. As shown, each channel L comprises an upper portion inclined slightly to the vertical and intersecting the corresponding channel I adjacent but below the upper side of the deck member. The lower portion of the channel L is vertically disposed and is lined by s a tubular metallic part M which has a laterally extending tubular branch M' connected to the corresponding horizontal rich gas distribution pipe O. The pipes O, one for each heating wall, are embedded in the deck member. Each pipe O extends from one side to the other of the battery and is connected, and supplies rich fuel gas to all of the combustion flues B in the corresponding heating wall. Each branch channel L is connected by a horizontal passage P to a second branch channel L. Each of the two branch channels L connected by a passage P having their upper ends connected through the corresponding channels I to heating lues B in one of which the gas flow is up or down at any time during which the flow is respectively down or up in the other ilue. As shown, each two lues B thus having their lower ends connected through a corresponding passage P, are at opposite sides of a coking chamber and have their upper ends connected by a crossover channel C. Each tubular part M is shown as having its lower end closed by a cap M2 accessible for removal from the basement space JA.

In the use of the present invention, the rich fuel gas pressure in the distribution pipes O will ordinarily exceed the pressure o-f the atmosphere by several inches of water, and gas is supplied to each branch channel L through a restricted orifice Q ina` tubular nozzle member Q, having an externally threaded enlargement Q2 at its lower end which is removably held in a threaded seat formed in the corresponding member M. Each nozzle Q receives gas at its open lower and from the tubular branch M through which the corresponding member M'is connected to the corresponding distribution pipe O. The nozzle Q extends through an enlarged portion L of the channel L into a restricted, Venturi throat shaped portion L2 of the channel L. The associated passage P opens into the enlarged portion Ls of the channel L.

Each nozzle Q and the portions L' and L2 of the channel L in which theY nozzle is mounted thus form an injector in which the energy of the fuel gas jet discharged through the nozzle orifice Q creates a suction effect for drawing into the nozzle throat L2'productsof` combustion through the nozzle inlet chamber L', and associated passage P from the flue B to which the remote4 end of that passage is connected through intervening channels L and I.

Each passage P and the two branch channels E which it connects. thus collectively form a recirculatory connection between a pair of channels I which includes two injector nozzles Q, one adjacent each end and each associated with, but laterally displaced from the adjacent one of the two channels. In operation rich fuel gas is supplied under pressure alternately to the two injector nozzles Q of each recirculatory connection. Each injector nozzle Q supplied with rich fuel gas discharges that gas into the associated rich fuel gas supply channel P along with products of combustion drawn into admixture with that gas from the other channel P of the pair connected by said passage. The products of combustion thus drawn into admixture with and diluting the rich fuel gas supplied through each channel I to the corresponding heating flue B, burns in said flue in a flame which is longer than would be formed by the combustion of the rich fuel gas if not so diluted.

The nozzle orifices Q' through which fuel gas is supplied to the flues B of a heating wall also serve as measuring orifices relatively proportioned to supply the proper amount of gas to each of the different flues. As a result of the customary taper in the thickness, or width of each oven chamber and the heat radiation losses at the sides of the battery, some of the heating ilues require considerably more fuel than others. However, with a pressure drop through each of the measuring orifices of several inches of "water, the diameters of all of the different orices Q' of a heating wall will be quite small and ordinarily the average diameter will be of the order of .2 of an inch or less.

The effectiveness of an orifice Q for either its injection nozzle or its measuring purpose, will be materially impaired by the flow restrictive effect of even a very small particle of soot or other furnace dust which may lodge in, or partially bridge over the orifice.

Furnace soot and other furnace dust particles, descend through the such rich fuel gas supply channels in such considerate amounts that it has long been regular practice to make provisions for readily opening the lower ends of the rich fuel gasr supply channels of underflred coke oven batteries I for periodical cleaning purposes. With the channels L, formed and disposed as shown, they are relatively short and cool, and are wholly out of the path through which soot and sut particles pass down from the highly heater upper portions of the channels I and from the flues B into which the channels I open at their upper ends.

As shown in Figs. 1 and 3 a small lateral branch P extends downwardly from each-passage P to the underside of the deck U and is open at its lower end to the atmosphere. In operation with rich fuel gas the small amount of atmospheric air drawn into the corresponding passage P and its branch P will be adrnixed with the rich fuel gas and products of combustion then being delivered to the channel I leading to the corresponding combustible ilue B in which combustion is thenbeing initiated. The air thus included in the mixture of` rich fuel gas and products of combustion passing upward through the channel I contributes to the efficiency of combustion and has the beneficial effect of reducing the quantity of carbon deposited on the upper portion of the walllof the channel I.

When a coke oven battery of the typev and form shown in the drawings is heated by the combustionl of lean: fuel gas, itis practically impossible to supply enough heat to the coking charges to make the coking time as short as is frequently desirable and in lean gas operation any reduction in the thermal eciency of the battery is especially objectionable. A reduction in the thermal eii'iciency of a battery including channels like or analogous to the channels P, will inevitably occur in lean gas operation unless provisions are made to prevent or suitably minimize flow through the connecting channels P when the battery is operating with lean fuel gas. In the absence of preventive provisions, combustible and burning gases will be drawn by a sort of inverted siphon action from the lower ends of the combustion fiues in which combustion is then being initiated, into the lues through which products of combustion are then passing to the subjacent regenerators.

In the construction shown in Figs. 1-4 the iiow of combustible and burning gases through the channels P in lean gas operation, may be substantially prevented by their passing a small amount of air to the channels L through the distribution pipes O. As shown, means for supplying such air are incorporated in the means provided to supply rich gas to the pipes O. Said means comprise a rich fuel gas supply conduit R extending longitudinally of the battery and having a separate branch R running to each pipe O. Each branch pipe R' includes a reversing valve S and a cutoff valve T. The latter is kept open continuously during normal rich fuel gas operation, and is kept closed continuously during operation with lean fuel gas.

For the purposes of the present invention each cutoff valve T is formed with a special valve passage T'. The channel T is closed when the cutoff valve is in its open position, but when the cutoff valve is closed for lean gas operation the channel T' connects a compressed air supply pipe U to the corresponding distribution pipe O. The valve channel T then passes air into the corresponding distribution pipe O from the pipe U at a suitably small pressure so that air will seep through each orifice Q at the rate required to maintain a relatively quiescent body of relatively cool air in each associated injecto-r inlet portion L and associated channel P. rFhis body of relatively stagnant and relatively cool air operates to substantially prevent siphon flo-w through the channel P from the flue B in one heating wall to the ue B in an adjacent heating wall. The small amount of air passing through the pipe U may be supplied to the latter at a suitably low pressure by a small compressor provided for the purpose, or may be supplied thereto through a suitable reducing valve connection to the compressed air supply piping with which a coke oven battery is customarily provided for other purposes.

In lieu of, or in addition to the means just described for preventing flow through the conduits P, each of the latter may be provided with a suitable cutoff or closing device. Thus for example, as shown in Fig. 5, each channel P may be intersected by a passage V through which a valve plug V can be moved into and out of position in which it prevents flow through the channel P between the associated passages L and I, and prevents the flow of atmospheric air into the passage P from the passage V. As shown, the passage V is surrounded by a metal shell or casing V2 embedded in the deck J and extending downwardly from the under side of the latter. A member V3 in threaded engagement with the shell Vz is provided with a central threaded orifice receiving a threaded spindle V4 for the corresponding valve member V. The rotation of said spindle moves the valve member V' up into and down from the position in which it closes communication between the opposite end'of the corresponding passage P. As shown, the portion of the passage V which directly intersects the passage P is conical, and the valve member V1 is conical and sized t0 t in the conical upper portion of the sleeve fare when adjusted into its upper portion, and to provide clearance for air flow through the passage V from the channel P when the valve V is lowered. Atmospheric air then enters the passage V through a small port V5 formed in the portion of the shell V2 below the under side of the deck J.

In lieu of providing a barrier to gas flow through each channel P during lean gas operation by supplying air to distribution pipes O from the pipe U in the manner illustrated in Fig. 3, or by the use of a removable valve plug o-r barrier V for each passage P as shown in Fig. 5, other arrangements may be made to prevent or impede flow through the passage-s P in lean gas operation.

Thus, as shown in Fig. 6, in lean gas operation each Venturi passage L2 may be closed by an individual stopper or plug W. The latter may be formed of metal but preferably is a ceramic body shaped to be supported in its operative position shown in Fig. 6 by the corresponding nozzle Q. The plug W may be readily put in place and removed through the lower end of the metallic tting lVlI when the corresponding nozzle V and plug Mz are removed. In Figs. 3 and 5, the arrows indicate the direction of flow during flow reversal period in which combustion is being initiated in the lue in communication with the upper end of the left hand one of the two channels L shown in each of said figures and with the valve member V' of Fig. 5 in an open position.

It will be apparent with those skilled in the art, the present invention can be used in any underred, vertically flued, regenerative coke oven battery in which it is practically feasible to provide a recirculatory connection between the lower end of each rich ygas channel running to one heating flue and the lower end of the rich gas channel running to a second heating ue in which combustion is initiated during periods alternating with those during which combustion is initiated in the first mentioned flue. As those skilled in the art will recognize, changes may be made in the form of the apparatus disclosed without departing from the spirit of the invention as set forth in the appended claims, and in some cases use may advantageously be made of some feature of the inventions disclosed and claimed without a corresponding use of other features.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

l. In an underflred regenerative coke oven structure comprising horizontal coking chambers alternating with heating walls formed with vertical heating lues, the combination with rich fuel gas supply channels extending upwardly from the underside of the structure and each connected at its upper end to a different vertical heating ue, of means for diluting the rich gas passed upwardly through each of said channels comprising a separate recirculatory connection between the lower end of each such channel and the lower end of an adjacent channel, the two channels of each pair thus connected at their lower ends being connected at their upper ends to heating nues, in one of which the gas flow is up or down during periods in which the gas flow in the other is respectively down or up, and two injectors in each recirculatory connection respectively associated with the two channels con nected by said recirculatory connection and each being laterally displaced from the channel with which it is associated and being adapted when supplied with rich fuel gas to discharge the latter into the associated channel along with products of combustion drawn from the other channel of the pair, and means for supplying rich fuel gas alternately to the two injectors in each recirculation connection.

2. A combination as -specied in claim l, in which each recirculatory connection comprises uprising end portions each inclined toward and intersecting the adjacent associated rich gas channel and in which the two injectors in each connection comprises a nozzle in one of the end portions, and the other injector comprises a nozzle in the second end portion of said connection.

. 3. A combination as specified in claim l in which each recirculatory connection comprises uprising end portions each inclined toward and intersecting the adjacent associated rich gas channel and in lwhich one of the two injectors in each connection comprises a nozzle in one of the end portions and the other injector comprises a nozzle in the second end portion of said connection, and in which the means for supplying rich fuel gas to the injectors comprises horizontal dis-l tribution pipes embedded in the lower portion of the voven structure and parallel to the coking chambers and heating Walls.

4. In an underflred regenerative coke oven structure comprising horizontal coking chambers alternating with heating walls formed with Vertical heating fines, the combination with rich fuel gas supply channels extending upwardly from the underside of the structure and each connected at its upper end to a different vertical heating flue, of means for diluting the rich gas passed upwardly through each of said channels comprising a separate recirculatory connection between the lower end c-f each such channel and the lower end of an adjacent channel, the two channels of each pair thus connected at their lower ends being connected at their upper ends to heating flues, in one of which the gas flow is up or down during periods in which the gas flow in the other is respectively down or up, and two injector-s in each recirculatory connection respectively associated with the two channels connected by lsaid recirculatory connection and each being adapted when supplied with rich fuel gas to discharge the latter into the associated channel alongwith products of combustion drawn from the other channel of the pair, means forsupplying rich fuel gas alternately to the two injectors in each recirculation connection and restricted connections betweensaid recirculatory connection-s and the atmosphere whereby a small amount of air isdrawn into adm-igture with the fuel gas and products of combustionpassing to the flues in which combustion is being initiated and means for preventing flow through said connections in operation with lean fuel gasp Y 5. In an underred regenerative coke oven structure comprising horizontal coking chambers alternating with heating Walls formed with vertical heating nues, the combination with rich fuel gas supply channels extending upwardly from the underside vof the structure and each connected at its upper end to a different vvertical heating flue, of means for diluting the rich gas passed upwardly through each of said channels comprising a separate recirculatory connection between the lower end of each such channel and the lower end of an adjacent channel, the two channels ofeach pair thus connected at their lower ends being connected at their upper ends to heating flues, in one of which the gas flow is up or down during periods in which the gas iiow in the other is respectively down or up, and two injectors in each recirculatory connection respectively associated with the two channels connected by said recirculatory connection and each being adapted when supplied with rich fuel gas to discharge the latter into the associated channel along with products of combustion drawn from the other channel of the pair, means for supp1ying rich fuel gas alternately to the two injectors in each recirculation connection and means operable to impede ow through each of said recirculatory connections.

6. A combination as specified in claim, 5 in which the means operable to impede flow through the recirculatory connection bleeds atmospheric air into said connections and thereby creates an air barrier to said ow.

7. A combination as specified in claim 5 in which the means for impeding ilow through said recirculatory connections comprise valves adjustable to obstruct now through said connections.

CARL OTTO.

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