US2082215A - Regenerative coke oven - Google Patents

Description

June 1, 1937. c T

REGENERATIVE COKE OVEN Filed Jan. 20, 1934 2 Sheets-Sheet ATTOR N EY June 1, 1937. c. OTTO REGENERATIVE COKE OVEN Filed Jan. 20, 1934 2 Sheets-Sheet 2 Uh MQ Patented June 1, 1937 UNITED STATES REGENERATIVE COKE OVEN Carl Otto, Essen, Germany Application January 20, 1934, Serial No. 707,485 In Germany October 6, 1933- 10 Claims.

This invention relates to regenerative ovens intended for the production of gas and coke of that class of oven comprising coking chambers alternating with heating walls each containing a great number of heating fiues, in which each two rows of heating flues cooperating according to the reversal of flow are in communication by channels which run over the coking chambers situated between therespective heating walls. In a known construction of such oven the heating flues are united in groups of about five fiues. The heating flues of such a group open into an upper horizontal channel and the horizontal channels of neighboring heating walls are interconnected by ducts extending over the intermediate coking chamber. This construction suffers from the drawback of considerable differences of pressure arising due to the sudden changes of direction and speed the gas undergoes in the passage from one heating wall to the other. In addition, the resistances of the gas are not uniform in all the heating fiues, so that special regulating means must be provided, in order to obtain an absolutely uniform heating effect.

The present invention has for its object to overcome this drawback which object is achieved by the fact that only two heating fines of different rows of heating fiues are interconnected by a special connecting channel which extends over the intermediate coking chambers. This connecting channel is U-shaped and its upper horizontal portion has a much smaller cross sectional area than the heating flues interconnected by it. This cross sectional area, however, is determined so as not to be smaller than required for the maintenance ofa laminary flow. The constriction of the channel from the cross section of the heating flue to its smallest cross section takes place gradually in the vertical portion of the channel which portion is the direct. pro longation of the respective heating flue. The connecting channel thus acts like a Venturi pipe and does not cause any additional resistances worth mentioning in the path of the gas. Furthermore, a gradual transformation .from the rectangular cross section of the heating fiues to the preferably circular cross section of the connecting channel may be provided in the constricted portions.

Furthermore, instead of each one heating flue of two heating walls, two neighboring heating fiues of two heating walls may be interconnected by one sole such connecting channel which leads over the intermediate coking chambers. The upper ends of the heating lines in this case are thermal decomposition.

united with slight inclination and open in common into the vertical portions of the U-shaped connecting channel. Preferably also the constriction is provided in the inclined portion as well as a gradual transformation of the rectangular cross sections of the heating flue to semicircular ones which unite to a circular cross section on the place where the heating fiues open into the vertical portion of the connecting channel.

The refractory brickwork above the coking chambers of course is more highly heated by the connecting channels, even if a great speed of the gas prevails in the latter and the heat radiation is kept low by the application of laminary flow. The increase in temperature of the brickwork above the coking chambers tends to the heating of the gases of distillation produced in the respective coking chambers and sucked through the upper gas collecting spaces thereof into the hydraulic mains to a temperature high enough to produce decomposition of those gases. It is, therefore, a further object of the invention to avoid such decomposition. This object'is attained by the provisions made for passing the gases of distillation from the oven chambers to the hydraulic main. These provisions include a number of openings distributed along the entire length of the top of each coking chamber and connecting the latter to ahorizontal gas dis charge duct provided in the oven cover and extending parallel to the length of the oven chamber and connecting the latter to the hydraulic main. Such gas discharge ducts in the oven cover are well-known per se. The arrangement according to the invention, however, is peculiar in so far as the U-shaped channels connecting the heating fiues of different heating walls extend above the coking chamber at a sufiicient distance below the gas discharge ducts in the oven cover, so that the latter are not heated to an extent worth noting from the connecting channels and thus remain cool enough to secure a discharge of the gases of distillation without In coking chambers which possess only one central filling hole the gas discharge ducts begin in the vicinity of the latter and lead on both sides to the two hydraulic mains situated on theends of the coking chamber.

Advantageously regulating means are provided on the places of connection between the top gas collecting space and the gas discharge ducts in the oven cover, so that a more or less great cross sectional area can be established here. In this manner the gas of distillation can-be caused to flow in a determined ratio immediately through the top gas collecting chamber and through the gas discharge duct.

For, tests have shown that the gas of distillation escaping from a coal coked at a determined temperature has different composition if after its production it is led through spaces of different temperature. In particular, it has been found that the yield of benzole and of hydrocarbons of similar properties, at a medium temperature of the space the gases must traverse after their production first is lower than at somewhat higher temperatures, tor example 800 C. for a certain sort of coal, and that with further increase of the temperatures of said space the yield of benzole etc. sinks again. Thus there is a maximum yield at a determined temperature of the space.

According to the coking times or to the final 0 temperatures employed in the coking operation, therefore, in order to obtain a maximum yield of benzole etc., the gases must traverse spaces the temperature of which must be not too high and not too low. By adjusting the cross sectional area of the openings of the top gas collecting space into the gas discharge duct and by suitably regulating the suction it is thus possible to cause the gases of distillation to remain a longer or shorter period of time in the gas collecting space and in the said openings and to obtain in this manner a maximum yield of benzole and benzolelike hydrocarbons under the varying conditions of operation of the coking plant.

In order that the invention may be clearly understood and readily carried into effect, two embodiments of chamber ovens, according to the invention, are illustrated by way of example in the accompanying drawings in which the Figures 1a to 4a show an embodiment in which each one heating flue of a heating wall may cooperate with a heating flue of another heating wall for series flow through the two flues in either direction, while in the embodiment shown in Figures 112 to 4b two neighboring heating flues of every heating wall are united and connected with two corresponding heating flues of a neighboring heating wall by one sole channel leading over the coking chambers. In particular Figures 1a and lb are vertical sections of the top portion or a chamber oven battery, seen in the longitudinal direction of the latter and, re-

spectively, on lines IaIa of Figure 3a and Ib-Ib of Figure 31),

Figures 2a and 2b are sections parallel to the first-named ones, on line 11-11 of Figures 4a and Figures 3a. and 3b are vertical sections seen in the longitudinal direction of a heating wall through the top ends of the heating flues, on the 0 lines IIIa-IIIa and IIIb-IIIb of Figures 1a and 112, respectively,

Figures 4a and 4b are vertical sections of the top portion of a coking chamber in the longitudinal direction thereof, on the lines IVaIV and 5 IVb-IVb of Figures 1a and lb, respectively, and.

Figure 5 shows four horizontal sections of the upper constriction of the heating flues, on the lines A, B, C, D of Figure 3b.

In the arrangement of Figures la to 4a rows of vertical heating flues 2 are provided between the horizontal coking chambers I. The heating flues 2 attop open into constrictions 3 interconnected by a connecting channel 4 which extends above the intermediate coking chamber. Two 7 neighboring heating walls need 991 P9 y be interconnected by such connecting channels 4, but also more distant heating walls may cooperate in the reversal of the flow. Thus, it is pos sible for instance to connect within a group of four adjacent heating walls. the heating flues of the first wall with those of the third and the flues of the second wall with those 01' the fourth. Also the heating flues of the first and fourth and those of the second and third wall may be interconnected and cooperate in the reversal of the flow.

The gases oi. distillation are sucked from the coking chambers not directly from the gas collecting space situated above the charge, but through special gas discharge passages 5 provided in the oven cover and communicating with the collecting spaces by a number of vertical ducts 8 distributed on the entire length of the chamber. By means of damper bricks I the size of the openings 6 can be regulated as desired. From the ducts 5 the gases are sucked through ascension pipes 8, situated at the ends of the chambers, into the hydraulic main (not shown). The chambers are charged each through one sole central filling hole 9.

The embodiment illustrated in Figures 1b to 4b differs from that described by each two neighboring heating flues being united upwardly and connected by a common connecting channel with two heating flues of a neighboring wall, with which they cooperate in the reversal of the flow. The constrictions I0 01' the heating flues are somewhat inclined to one another so as to unite at their narrowest portion, where they form the connect ing channel H proper. The advantage of this arrangement resides in the feature that the number of the connecting channels is reduced one half whereby the construction of the oven cover is simplified.

It will be seen by the section of Figure 5, how the rectangular cross section of the heating flues within the constriction goes over into a semicircular one from which then results the circular cross section of the connecting channel I l proper.

Such variation inthe cross sectional shape of the 'cross over connection is especially advantageous for the purposes of applicant's invention, since it contributes to a desirably small pressure drop in the cross over connection, and to the maintenance of laminar flow in the circular, most restricted portion of the connection. As is well known, the tendency of the flow to pass from the laminar into the turbulent condition increases with an increase in the velocity of the flow which results from a restriction in the cross section of the flow passage. The laminar flow can be maintained with a higher flow velocity in a flow passage of circular cross section than in a flow passage of any other cross section. Since the vertical heating flues are necessarily rectangular, or approximately rectangular in cross-section, the formation of the tapering lower portions of the cross over connection with rectangular cross sections, permit those tapering lower portions to merge smoothly into the vertical heating flues, thereby avoiding flow disturbing eddies which interfere with the maintenance of laminary flow and increase the pressure drop through the cross over connection. As has been pointed out, applicant's cross over connection is in eflect a Veraturi flow passage, and this, of itself, contributes to a low pressure drop in the connection. The full advantage of a Venturi flow passage in minimizing pressure drop requires a suitably smooth merging of the ends of the Venturi passage proper -make the diameter and cross section of the throat portion of the channel as small as is practically possible. To minimize the gas pressure reduction,-or loss of pressure head, in the channel, and to minimize the heat transfer through the channel wall, it is practically desirable, however, that the throat portion of the cross-over channel should have a cross section large enough to insure a laminary fiow through the channel, with the maximum volume of gas flow through the channel under normal operating conditions. With the proportions shown in Fig. 5, the cross section of the throat is approximately one tenth of the cross section of the two flues 2 to which the cross-over channel is connected at either end, so that the velocity of flow through the throat portion of the cross-over channel is about ten times the velocity of flow in the upper portion of each flue 2 delivering heating gases to, or receiving such gases from the channel. This ten to one ratio of cross sections and flow velocities represents a safe practical compromise, in the oven arrangement shown in Figs. 30-5, between the desire on the one hand to make the cross section of the throat portion of the channel as small as is practically possible, and the desire on the other hand to maintain a laminary flow through the cross-over cha nnel with the maximum normal velocity of flow therethrough.

What I claim is:

1. An oven for producing gas and coke comprising alternate coking chambers and heating walls arranged side by side, vertical heating flues in each heating wall arranged side by side in a row extending longitudinally of said wall, and channels communicably connecting the upper ends of flues in each heating wall to the upper ends of flues in another heating wall, each of said channels being of inverted U-shape and comprising one leg portion extending upward from and communicating at its lower end with a flue or flues in one heating wall, a second leg portion extending upward from and communicating at its lower end with aflue or flues in another heating wall, and a portion intermediate the upper ends of said leg portions, and each of said channels forming a single Venturi tube form flow path having end portions tapering in cross section along their lengths and formed by the corresponding leg portions, each of the latter diminishing in cross section from its lower end to its connection withsaid intermediate portion, and having a throat portion formed by the said intermediate portion of the channel and of a cross section not greater than the minimum cross section of each corresponding leg portion. 7

2. A regenerative oven for producing gas and coke comprising alternate coking chambers and heating walls arranged side by side, vertical heating flues in each heating wall arranged side by side in a row extending longitudinally of said wall, and channels communicably connecting the upper ends of flues in each heating wall to the upper ends of flues in another heating wall, each of said channels being of inverted U-shape and comprising one leg portion extending upward from and communicating at its lower end with .aflue or flues in one heating wall, a second leg portion extending upward from and communicating at its lower end with a flue or flues in another heating wall, and a portion intermediate said leg portions, and each of said channels forming a single Venturi tube form flow path having end portions tapering in cross section along their lengths and formed by the corresponding leg portions, each of the latter diminishing in cross secticn'from its lower end to its connection with said intermediate portion, and having a throat portion formed by the said intermediate portion of the channel and of a cross section not greater than the minimum cross section of each corresponding leg portion, the said leg portions of each channel-being similar in form, sothat its Venturi tube flow action is; the same for flow through the channel in either direction.

3. An oven for producing gas and coke comprising alternate coking chambers and heating walls arranged side by side, vertical heating flues in each'heating wall arranged side by side in a row extending longitudinally of said wall, and channels communicably connecting the upper ends of flues in each heating wall to the upper ends of flues in another heating wall, each of said channels being of inverted U-shape and comprising one leg portion extending upward from and communicating at its lower end with a flue or flues in one heating wall, a second leg portion extending upward from and communicating at its lower end with a flue or flues in another heating'wall, and a portion intermediate said leg portions, each of said channels forming a single Venturi tube form flow path having end portions tapering in cross section along their lengths and formed by the corresponding leg portions, each of the latter diminishing in cross section from its lower end to its connectionwith said intermediate portion, and having an elongated throat por-- tion formed by the said intermediate portion of the channeL'and of a cross section approximately constant along its length and not greater than the minimum cross section of each corresponding leg portion.

4. An oven as specified in claim 10in which each Venturi tube flow path forming channel is proportioned relative-to the volume of heating gas flow there-through to insure a laminary flow through the throat portion of the path with the maximum normal volume of heating gas flow through the channel.

5. An oven as specified in claim 1 in which each leg portion of each Venturi tube flow forming channel is bifurcated at its lower end with one bifurcation communicating with one and the other bifurcation communicating with another vertical heating flue.

6. An oven as specified in claim 1 in which each of said channels varies gradually in cross sectional contour from a circular form in the portion intermediate its ends, into a rectangular form adjacent each heating flue with which it communicates.

'7. An oven for producing gas and coke comprising alternate coking chambers and heating walls arranged side by side, vertical heating flues in each heating wall arranged side by side in a row extending longitudinally of said wall, channels communicably connecting the upper ends of flues in each heating wall to the upper ends of flues in another heating wall, each of said channels being of inverted U-shape and comprising one leg portion extending upward from and communicating at its lower end with a flue or flues in one heating wall, a second leg portion extending upward from and communicating at its lower end with a flue or flues in another heating wall, and a portion intermediate said leg portions and extending over the top of each coking chamber between the flues with which the said leg portions respectively communicate. and each of said channels forming a single Venturi tube form flow path having end portions tapering in cross section along their lengths and formed by the corresponding leg portions, each of the latter diminishing in cross section from its lower end to its connection with said intermediate portion, and having a throat portion formed by the said intermediate portion of the channel and of a cross section not greater than the minimum cross section of each corresponding leg portion, and a horizontal distillation gas discharge duct above and parallel to each coking chamber and vertically displaced from said channels, and passages horizontally displaced from said channels and connecting said duct to the top of the chamber at points distributed along the length of the latter.

8. An oven for producing gas and coke comprising alternate coking chambers and heating walls arranged side by side, vertical heating flues in each heating wall arranged side by side in a row extending longitudinally of said wall, channels communicably connecting the upper ends of flues in each heating wall to the upper ends of flues in another heating wall, each of said channels being of inverted U-shape and comprising one leg portion extending upward from and communicating at its lower end with a flue or flues in one heating wall, a second leg portion extending upward from and communicating at its lower end with a. flue or flues in another heating wall, and a portion intermediate said leg portions and extending over the top of eachcoking chamber between the flues with which the said leg portions respectively communicate, and each of said channels forming a single Venturi tube form flow path having end portions tapering in cross section along their lengths and formed by the corresponding leg portions, each oi'the latter diminishing in cross section from its lower end to its connection with said intermediate portion, and having a throat portion formed by the said intermediate portion of the channel and of a cross section not greater than the minimum cross section of each corresponding leg portion, and a horizontal distillation gas discharge duct above and parallel to each coking chamber and above the level of the tops of'said channels, and passages horizontally displaced from said channels and connecting said duct to the top of the chamber at points distributed along the length of the latter.

9. An oven as specified in claim 1, in which the cross section of the throat portion of the said Venturi tube form flow path is not greater than approximately one tenth of the cross section of the flue or flues to which said path is connected at either end.

10. An oven as specified in claim 1, in which the cross section of the throat portion of the Venturi tube form flow path is a relatively small fraction only of the cross section of the flue or flues to which said path is connected at either end, but is large enough for the maintenance of laminary flow through said path with the maximum normal volume of heating gas flow therethrough.

CARL OTTO.

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