US2255406A - Coking retort oven - Google Patents

Description

Sept. 9 1941. BECKER 2,255,406

COKING RETORT OVEN INVENTOR.

BY m

ATTORNEY.

Patented Sept. 9, 1941 come nn'ron'r oven Joseph Becker, Pittsburgh, Pa., assignor to Koppers Company, Pittsburgh, Pa., a corporation of Delaware Application October 11, 1938, Serial No. 234,357

4 Claims.

The present invention relates to regenerative by-product coke ovens in general and pertains more specifically to new and improved means for simply and effectively promoting the facility with which regularity of heating is establishable along the heating walls of coking structures provided with contiguous vertically-disposed heating flues.

The permanent gases evolved from coking coals when subjected to a process of carbonization vary in their composition from coal to coal and also alter in the case of an individual coal with change of coking time, temperature of distillation, and the like, even when the coke-oven plant is being operated within the temperature range commonly designated as that of high-temperature carbonization. Under some conditions of carbonization, a coal will yield in the total mixture of permanent gases relatively higher percentages of hydrogen, for example, than when subjected to other conditions of distillation, or will produce gases having relatively higher carbon-bearing compounds under certain conditions than are formed under others. Operators are confronted from time to time with the problem of effectively utilizing heating gases that are of significantly different compositions and buming characteristics for establishing throughout their heating walls thermal conditions which will coke portions of the coal charge remote from the bottoms of the heating flues in substantially the same period of time as is required for other parts of said charge more closely adjacent the bottoms. If such regularity of heating is not established it may be necessary, in order to maintain the pushing schedule, to subject some levels of the heating flues to excessive temperatures, especially those parts adjacent the gasand air-ports, in order to bring all parts of the oven charge to the required degree of coking within the time allotted by thepushing schedule.

Hydrogen and compounds of hydrogen and of carbon are the principal heat-producing constituents of fuel gases. Hydrogen itself and also fuel gases of increasing hydrogen content tend to burn with a hot short flame and the heat evolved by its combustion tends to be given oil quickly at a point adjacent the burner, whereas fuel gases containing larger amounts of carbonbearing compounds formulae tend to burn slowly with production of a longer flame and a closer approach to a uniform distribution of their heats of combustion. Under the first-mentioned set of operating conditions there may exist a tendency for the heatproportions of complex of increasingly complex ing walls locally (1. e. at the bottoms of the'heating flues), to transmit a quantity of heat in excess of that required for a preferred rate of progress of the coking reaction or which can be sufficiently rapidly absorbed by the coal, whereas, under another the second mentioned set of operating circumstance, those zones which, under the first set of circumstances, were subjected to unnecessarily high temperatures may be cooler than preferred. The result is either a locally too rapid coking of the oven charge or unnecessarily high temperatures in some of the brickwork, or vice versa, heating-wall zones at lower than desired temperatures. Thus, a setting of the gas and of the air regulatory means suitable for obtaining satisfactory underflring results with fuel gases which burn with a short flame, may be quite inappropriate for establishing the desired coking conditions in the case of fuel gases that burn with a longer flame.

An object of the present improvement is therefore the provision, for coking retort ovens having modern dimensions, of an improved flexibility in respect of heating gases that can be satisfactorily and successfully employed for their underfiring, so that the coke-oven operator will be enabled to obtain with greater facility the desired regularity of heat distribution along the heating walls of such ovens irrespective of changes in operating conditions or of coals employed or of diversity of burning characteristics of the available heating gas.

A specific object of the instant invention is to furnish, more especially for coke ovens having vertically-fined heating walls, replaceable means that can be simply and optionally installed in and removed from an existing coking structure and which will enable the operator to displace the initial point of combustion in the heating flues to preferred positions above the bottoms thereof, and the bottom of the coal charge itself.

Another object of invention is to utilize the replaceable means in such appropriate position in respect of the combustion media inlet to the heating flues as will obviate the possibility of stoppages developing in said means by the deposition of carbon that results from the cracking of rich heating gases as they enter the hot flues, so as to preclude vexatious policing by rodding or the like which otherwise is required in order to maintain uniformity of flow of the combustion media. The invention has for further objects such other improvements and such other operative advantages or results as may be found to obtain in the conducted to the bottom of the coal charge.

' fuel gas that is not regeneratively preheated and,

in general, the ports through which all these gases are introduced into the flues are located in juxtaposition and, ordinarily, they he very close to if not in the same plane as that which contains the bottoms of the coking chambers in order that evolution of the heat given off by the buming of the underfiring gas in the heating flues will start at a point where a part can be rapidly In coke ovens having gas-distributing settings that are an integral and permanent part of the brickwork, ideal heating results can only be realized when employing a fuel gas of unchanging burning characteristics. However, from the hereinabove recited, it is obvious that coke ovens must be easily adaptable to the use of fuels of substantially different properties if the heating results obtained are not to be merely a compromise between the desired and the realizable because of the inconstancy of the combustion characteristics of the available fuel gases. By means of the present invention, it is possible to start the combustion of a gas producing a hot short flame at such points in the heating flues where there is a larger 'quantity of the to-be-coked coal more closely thereadjacent to absorb the evolved heat than in those instances where the employed heat irg gas burns with a less hot and longer flame. For example, with the present invention in coke ovens having the bottom of the flues at the same level as the bottom of the adjacent coking chamber. a gas of the former type can be first ignited in the fiues at some point above that at which the latter is ignited, i. e. at a point where there is more coal immediately contiguous thereto for removing the flrst heat of combustion from the flame, and vice versa.

According to the present invention there is provided, more especially for vertically-fined coke ovens, a simple tube-like conduit or nozzle-brick that is removably mountable in the ports of those ducts that communicably connect the heating flues with their regenerators and from which po-- sition each is arranged to extend a substantial distance upwards into the heating flue. The point at which gases enter the combustion zone of the heating fiues from the regenerators can thus be regulated as preferred by the length of the tube employed and the point of initial combustionin a heating flue can be optionally shunted to a zone further up the flues than that provided by the brickwork of an existing flue structure. In effect the device of invention serves to defer the mixing in the flues of a regeneratively preheated gas and a non-regeneratively-preheated gas and thereby displaces the hottest part of the resulting flame toan increased level above the bottom of the coking chamber. In making possible this highly desirable result by use of means that are associated only with the ports for flowing the regeneratively preheated gases into the heating flues; an especial advantage results. The gases normally introduced into the heating flues from regenerators are air in the case of rich gas under- In addition to firing. or air and a gas of low thermal content in the case of lean gas underfiring. Air is entirely without tendency to deposit pyrogenetically-derived carbon on the inner walls of the device of invention and, to the contrary, will consume any such carbon adventitiously deposited there. In the case of lean gases whose carbon contents is so low that they must be preheated to secure proper heats therewith, the like obtains. In the cases of both types of underfiring therefore, the oven operator has the assured advantage that once the length and cross-section of such a tube has been determined for a specific location and there-installed, it will require no further attention in the way of policing to maintain the desired port cross-section as is the case in contrary practice where rich gases are fiowed into the hot heatingflues through ducts of significant length to effect a similar result.

In its preferred embodiment, the invention comprises a tube of heat-resisting material, preferably silllmanite, arranged to be removably supported in the port of a duct that communicably connects a heating flue with its regenerator, and thereafter to extend substantially vertically upward into said heating fiue any desired distance. Although it is also preferred to have said tube so supported in said port that it is out of contact with the flue walls, it may of course without departing from the spirit of the invention be removably supported against the fiue wall in the interests of stability, when a modification of design so requires. In any one heating wall, it is in addition preferable so to graduate the area of the ducts of said tubes from the pusher to the coke side of the battery that their effective cross-sections increase according to the demands of the taper of the adjacent coking chamber, with the exception of course of the end flues at both battery sides where larger amounts of gas are normally burned to compensate for the greater radiation from the fiues so-positioned. The tubes of invention are in addition provided with means whereby they can be placed in or removed from operating position and may be of such dimensions as to be admitted into the heating flues through those inspection holes that open to the top of the battery.

In the accompanying drawings forming a part of this specification and showing for purposes of exemplification a preferred apparatus in which the invention may be embodied and practiced but without limiting the claimed invention specifically to such illustrative instance or instances;

Fig. 1 is a crosswise vertical section partly through a heating wall and partly through a coking chamber of a coke-oven battery of the Becker type embodying above-specified features of invention and showing a portion of the regenerators therebeneath;

Fig. 2 is an enlarged section taken along the line 11-11 of Fig. 1, parts being broken away, and showing the graduation from the pusher to the coke side of the battery, of the effective crosssectlons of the ducts that extend through the nozzle-bricks of invention for adjusting the point in the heating fiues at which regeneratively preheated gases first enter the zone for combustion in the heating flues;

Fig. 3 is a complete vertical section taken lengthwise of the battery illustrated in Fig. 1, the sections A-A, Bi-B, being taken respectively along the lines AA and BB of that lengthwise of a battery similar to that shown in Figs. 1, 3, but having an arrangement of regenerators disposed for underfiring the structure with coke-oven gas or a regeneratively preheated lean gas.

The same characters of reference designate, the same parts in each of the views of the drawings.

Referring now to the drawings, particularly Figs. 1, 3, there is shown a standard coke-oven battery with coking chambers l disposed lengthwise of the battery in alternation with heating walls II. The heating walls are each divided into a plurality of vertically-extending heating flues [2, the heating fines of each heating wall being operatively divided into groups of four flues by a short horizontal canal i3 (with the exception of the end-flues which have individual crossovers) through which all the combustion-products from one flue-group pass before entering the crossover duct N to be conducted over the top of an adjacent coking chamber, in the well-known manner characteristic of the Becker oven, and into a correspondingly positioned flue group in the heating wall adjacent the opposite side of the intermediate coking chamber l0.

Each heating flue of a heating wall is communicably connected directly with an underlying cross-regenerator l5 by means of a conduit l6 through which gas, that has been distributed by sole-channels 2| over the checker-brickscontained in each such cross-regenerator and by them preheated, is delivered to the individual heating lines. The heating flues each also communicate with a source of fuel gas that is not regeneratively preheated by means of ducts l1 that branch off the conduits l8 located in the capitals of those pillar walls [9 which both support the thereabove heating walls of the coking structure and separate from each other the cross-regenerators associated with adjacent heating walls.

In the operation of the coke-oven battery shown in the drawings, air that has been regeneratively preheated in the cross-regenerators l5 enters the lower parts of the heating flues individually through conduits l6 where it comes into contact with fuel gas that is introduced through ducts H from conduit l8 connected with a reservoir of rich fuel gas outside the battery structure. These two gases gradually admix and burn as they rise through the heating flues and give up heat to the surrounding brickwork,

eventually arriving in the short horizontal flues whence they pass into crossover duct I, over the top of the coking chamber into the therewith connected flues in the opposite heating wall. Periodically the direction of gaseous flow is reversed in the well-known manner and the up-flowing'flues become the down-flowing flues, and vice versa.

The upper ports of both the conduits l6 and ducts II, as far as the permanent structural masonry of the heating walls is concerned, lie at the bottoms of the heating fiues on a level with the bottoms of the coking chambers. Each of said ports is provided with a removably placed nozzle-brick which may be changed by means of a, long rod inserted through inspection holes 20 that give access to the bottoms of the heating lines from the top of the battery. The ducts perforating these nozzle-bricks generally are graduated in size so that in progression from the pusher-side to the coke-side of the battery increasing amounts of fuel gas can be introduced into consecutive flues to supply the heat required by the larger quantities of coal opposite each heating flue in consequence of the conical shape of the coking chamber. In the battery shown in the drawings, the inner walls of both ducts l6, ll, adjacent their upper ports are provided with inclined surfaces or bevels which support the flow-regulating nozzles which are also provided for the purpose with correspondingly beveled surfaces susceptible of registration with the beveled surfaces of the respective fuel-gas ports and air ports to support them therein.

In the coke-oven battery shown in the drawings, the ports through which regeneratively preheated gases, as well as those through which gases that are non-regeneratively-preheated are introduced into the heating fines, are arranged in substantially the same plane in the permanent brickwork of the battery, said plane being at practically the same level as that of the bottom of the coking chambers l0, thereby providing an opportunity for the heating gases to start their combustion close to the very bottoms of the coking chambers and adjacent the bottom of the coal charge therein.

When, however, under combinations of operating conditions and circumstances of which some have been hereinbefore indicated, it becomes expedient to defer the initial mixing in the heating fines of the regeneratively and non-regeneratively-preheated combustion media, such for example as obtains when it is observed that the bottoms of the heating flues are being maintained at a temperature higher than preferred, causing a too rapid heating of the lower parts of the ovencharges, the present invention provides means whereby inauguration of combustion can be displaced to a point further along the length of the flues. Such new setting may be continued in operation until such time as new influences make advisable a further adjustment of initial mixing of the heating gases.

Accordingly the regenerator ports of structurally permanent position are each optionally provided with a nozzle-brick 22 that extends upwards into the flues, preferably free of contact with the walls thereof, to a point higher than that point to which the nozzle-bricks 23 for the non-regeneratively-preheated gas reach so that the initial combustion between the air and fuel gas will take place at a point higher in the fiues than when the said ports are both supplied with shorter nozzle-bricks of the same height.

I In the embodiment shown in Fig. 6, the nozzlebrick 22 is beveled at 24 to register with a siman upright position. Theouter walls of the said brick 22 are preferably frustrum-like in shapeso as to promote a stream-like flow of the heating gases issuing from the nozzle-brick 23 although it is of course understood that such walls may be provided with other contours; for example, they may be cylindrically shaped or provided with projections for creating eddies if preferred in the surrounding gas without departing from the spirit of the invention. The recess 25 in the inner walls of the nozzle-brick are adapted to receive the hook at the lower end of rod 26 which is of sufficient length to enable the operator to insert said nozzle-brick through the flue-inspection hole 20 and conveniently adjust it into position in the upper port of conduit l6. Duct 21 of nozzle-brick 22 regulates the volume of regeneratively preheated gases that enter the flues and may be of any preferred cross-section or area, and it is preferred to provide those employed in any one heat.- ing wall with diverse areas so that increasing amounts of gas can be introduced into the flues successively from pusher-side to coke-side of the battery according to the demands of the taper of the coking chamber.

It is further preferred to form the nozzle-bricks of the instant improvement from the material sillimanite (A1(AlO)SiO4) which is very highly refractory to heat and has the further advantage that it lends itself to molding into shapes of very accurate proportions, although such materials as silica, clay, carborundum, and the like, may be used if p eferred.

The present improvement has the advantage that its objects are achieved without flowing combustion media that are susceptible of serious pyrogenetic decomposition through tubes of appreciable length which are exposed to a high degree of radiant heat from the heating walls, as would be the case were the nozzle-bricks of the invention employed in conjunction with rich gases of the carbonization process that normally contain large amounts of complex hydrocarbons easily broken down. Thus, by employing the removable nozzle-bricks of the improvement only in combination with combustion media that have previously passed through the regenerators, all

such inconveniences of operation are entirely avoided. Of further advantage is their feature of removability from the regenerator ports, or even from the battery structure itself.

The advantages of the invention also can be realized in gas ovens or combination coke ovens as well as ovens intended for operation exclusively as coke ovens, such as shown in Fig. 3.

In Fig. '7 there is illustrated a coke-oven battery of the general type shown in Figs. 1, 3, but of the combination" type. In this embodiment of the invention each heating flue is communicably connected by individual conduits 3|, l6, respectively with two regenerators 30, I5, of which the former is adapted to preheat lean gas and the other to preheat air and alternately to function as combustion-products regenerators in accordance with the solid-lined and dotted symbols G, A, WH, designating respectively gas, air and combustion products, said conduits being preferably arranged to converge and unite at a point below the bottom of the heating flues with which they communicate through a common port 32 in the manner shown in applicant's patent U. S. No.

2,100,762 granted Nov. 30, 1937. Such construction provides for some mixing of lean gas and air an interval before they are admitted to the heating flues so that their actual combustion starts before entering the zone for combustion therein. The result is that the said gases enter the flues at a somewhat higher temperature than would otherwise obtain. The common flue-port 32 of the two regenerator-conduits 3!, I6, is provided at its upper periphery with a beveledsurface similar to that shown for the flue-port individual to the One regenerator-conduit, more clearly shown in Figs. 3, 5, and the nozzle-brick of invention is in this instance also furnished with a beveled surface registerable therewith to support it in said port.

In a coke-oven battery thus adapted both for underfiring with either a rich or a lean gas when such battery is being heated with rich gas and all the in-flow regenerators are operating to preheat air exclusively, the point of initial combustion in the heating flue optionally may or may not be raised above the existing lower wall of the heating flues for the purpose of deferring the initial mixing of the combustion media. This efiect is also further enhanced by the shape of the flow-regulating duct in the nozzle-brick which tends to discharge said preheated air into the heating flues as a vertically-rising column having eddyless stream-like flow, and thus increasing the tendency to defer contact between the air and rich gas. At such times as said battery is underfired with a regeneratively preheated lean gas and air, the improved nozzle-brick may be optionally employed to introduce the already ignited gases into the heating flues at a higher level while also providing them with a stream-like flow, said nozzle-brick at. the same time serving as means for radiating to the lower part of the flue walls heat-of'the burning gases flowed therethrough. In addition, by the choice of the height to which the nozzle-brick is-arranged to protrude into the zone for combustion in the flues, the extent of the initial intimate mixing of the lean gas and air can be regulated with its obvious effect to accelerate or retard combustion. When underfiring with a preheated lean gas, the removal of the improved nozzle-brick from its operating position will subject the mixing lean gas and air entering the heating flues to the directional efiect of the beveled surface, which will induce them to flow toward those parts of the heating wall adjacent the bottom of the coking chamber when such effect is desired.

The invention as hereinabove set forth is embodied in particular form and manner and may be variously embodied within the scope of the claims hereinafter made.

I claim:

1. A combination horizontal coking retort oven having vertical combustion flues on opposite sides of an oven chamber adapted to be heated with regeneratively preheated air and selectively with either strong gas or regeneratively preheated weak gas, a strong gas nozzle and air and weak gas regenerator ducts porting into the vertical combustion flues at substantially the same level as the bottoms of the oven chamber for initial ignition of strong gas or weak gas at about the same level as the bottoms of the flues and oven chamber, the air and weak gas generators being adapted to be jointly operable for concurrent inflow of air for initial ignition at the base of the flues of strong gas concurrently supplied by the strong gas inlet duct therefor, or separately operable for simultaneous inflow of air and gas to the regenerator ducts for initial ignition thereof at the base of the flues; and auxiliary upwardly directed nozzles freely removable and interchangeable relative to the integral and permanent parts of the oven brickwork and mounted on both of the regenerator inlet ducts to the respective flues and adapted to have their ports dis-' charge both of the regenerator ducts at a substantial distance above the strong gas nozzles and regenerator ports at the base of the flues so that whether the regenerators are jointly operable for concurrent inflow of air or separately operable for simultaneously'inflow of air and fuel gas, initial ignition of the strong gas or weak gas entering from the nozzles and ducts therefor at the base of the flues optionally may be caused to take place at a level higher up in the flues, that is substantially higher than the initial ignition level of the top of the strong gas nozzles at the base of the flues and oven chamber, instead of atNthe level of the strong gas nozzles at the base of the fiues.

2. A regenerative horizontal coking retort oven having vertical combustion flues on opposite sides of an oven chamber adapted to be heated with regeneratively preheated air and strong gas, a strong gas nozzle and air regenerator. ducts porting into the vertical combustion flue bottoms at substantially the same level as the bottoms of the oven chamber, the air regenerator ducts and strong gas nozzles being adapted for initial ignition of the strong gas at about the same level as the bottoms of the'flues and oven chamber; and auxiliary upwardly directed nozzles freely removable and interchangeable relative to the integral and permanent parts or the oven brickwork and mounted on the inlet ducts of the regenerators to the respective flues and adapted to have their ports discharge the regenerator ducts at a subgas so that initial ignition of the strong gas entering from the nozzles at the base of the vertical heating flues with the air from the regenerators optionally may be caused to take place at a level higher up in the lines, that is substantially higher than the initial ignition level of the top of the strong gas nozzles at the base of the flues and oven chamber, instead of at the level of the strong gas nozzles at the base of the flues.

3. A coke oven as which the ducts of the pair of regenerators to each flue unite beneath the lower wallof the heating flue and enter it through a common port and in which the auxiliary nozzle for the ducts of the pair of regenerators comprises a single nozzle-' brick for the pair ofv ducts, with a single nozzle duct, removably mountable on the common port.

4. A horizontal coking retort oven having vertical combustion flues on opposite sides of an oven chamber with provision for heating with strong gas and regeneratively preheated air, air regenerator ducts leading into the bottoms of the flues, strong gas nozzles porting into the bottoms of the combustion flues at substantially the same level as the bottoms of the oven chamber, and upwardly directed nozzles on the air regenerator ducts having their ports arranged to extend the discharge of air from the air regenerators into the flues at a level "therein that is a substantial distance above the level of the top 0! the strong gas nozzles at the base or the fines.

\ JOSEPH BECKER.

stantial distance above the inlet ports for strongv claimed in claim 1 and in

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