US3197385A

US3197385A - Process of cooling down a regenerative coke oven battery

Info

Publication number: US3197385A
Application number: US157410A
Authority: US
Inventors: Wethly Frans
Original assignee: Allied Chemical Corp
Current assignee: Krupp Wilputte Corp; Allied Corp
Priority date: 1961-12-06
Filing date: 1961-12-06
Publication date: 1965-07-27
Anticipated expiration: 1982-07-27
Also published as: GB956538A

Description

July 27, 1965 F. wETHLY 3,197,385

PROCESS OF COOLING DOWN A REGENERATIVE COKE OVEN BATTERY Filed nec. ves. 1961 s sheets-sheet 1 F. WETHLY July 27, 1965 PROCESS OF COOLING DOWN A REGENERATIVE COKE OVEN BATTERY Filed Dec. 6, 1961 5 Sheets-Sheet 2 U... H. ...www HLW m @Fi l im] t l Wil' lul' IMI

Il INVENTOR July 27, 1965 F. wl-:THLY I 3,197,385

PROCESS OF COOLING DOWN A REGENERATIVE COKE OVEN BATTERY Filed DSG. 6, 1961 3 Sheets-Sheet 3 INVENTOR. v FM4/v5 wry-H4? United States Patent Ofce 3,197,335 Patented JulyZ'?, 1965 3,197,305 PRGCESS F CGLENG DGWN A REGENERA- TVE CKE @VEN BATTERY Frans Wethly, Manhasset, NSY., assigner to Allied Chemical Corporation, New York, NX., a corporation of New York Filed Dec. 6, 1961, Ser. No. 157,410 2 Claims. (Cl. 202-1) This invention relates `to the cooling down of coke oven batteries, and particularly to cooling down coke oven batteries from operating temperatures in the neighborhood of 2600" F. to ambient atmospheric temperature when, because of work stoppages, economic conditions, or for other reasons, it becomes necessary to cease operating the battery to produce coke.

Coke oven batteries, as is well known, have the heating Walls and the regenerator division walls constructed of silica brick, or have the heating walls to the oven soles of silica brick and the regenerator division walls of cheaper iireclay brickwork. Silica brick, when heated or cooled at temperatures below about 1200 F., expands or contracts, respectively. Above about 1600 F., no significant expansion or contraction takes place. Within the range of from 1200 to 1600 F., the extent of expansion or contraction, as the case may be, is relatively small. Temperature changes within the range of from 1200 to 1,000 F. cause expansion or contraction of the silica brick, as the case may be, of about 0.05%; within the range of from 1,000 to 800 F., contraction or expansion of the silica brick of about 0.06% takes place;

and within the range of from 800 to 600 F., the contraction or expansion of the silica brick, as the case may be, is of the order of about 0.12%. Below 600 F., the contraction or expansion of the silica brick is even more marked as compared with changes which take place from 600 to 800 F.

In view of the known thermal expansion characteristics of silica brick, it has heretofore been the accepted practice to maintain coke oven batteries, once heated up to operating temperatures, hot even during extended periods when there are no demands for coke. Operation of coke oven batteries under slow-down conditions, i.e., heating the battery over a greatly prolonged time cycle so as to decrease the coke production, has been employed to maintain the battery hot (at normal operating temperatures), and thus avoid crack formation therein. Alternatively, the heating walls of the battery have been heated without a coal charge in the coking chambers to maintain the heating walls of the batteries at a temperature of at least 1600 F. in an effort to keep the battery in a standby condition so that it can be operated once the demand for coke again arises. This procedure is disadvantageous in that it necessitates burning gas in the heating ilues with consequent economic waste; where a stoppage is for a relatively long period, this waste can be substantial.

Experience has demonstrated that if the battery is cooled down either deliberately to avoid the objections hereinabove pointed out, or accidentally, dierential shrinkage which takes place in the refractory brickwork results in either loss of the battery due to excessive crack formations chiefly in the heating walls, or, at best, marked curtailment of its useful life and loss of operating efflciency throughout the remainder of its shortened life.

lt is a principal object of the present invention to provide a process of cooling down coke oven batteries to ambient atmospheric temperature conditions Without excessive crack formation taking place in the battery, and which enables the battery to be reheated when desired, and again operated efficiently and economically.

Other objects and advantages of this invention will be apparent from the following detailed description thereof.

In the accompanying drawings forming a part of this application and showing, for purposes of illustration, a preferred embodiment of the invention,

FIGURE 1 is a fragmentary vertical section taken crosswise of the battery through a coking chamber of a regenerative coke oven battery, showing the battery modified in accordance with this invention so that it can be cooled down or heated up Without excessive crack formation;

FGURE 2 is a fragmentary, partially schematic, horizontal section on an enlarged scale as compared with the scale of FIGURE l, taken alone line 2 2 of FIGURE l, showing a tension rod extending through apertures in the coke oven doors for applying compressive stresses to the battery brickwork;

FIGURE 3 is a fragmentary, vpartially schematic, vertical section through the coking chamber showing the tension rod extending therethrough, greatly enlarged relative to the scale of FIGURE 1;

FIGURE 4 is a fragmentary vertical section taken along the line 4 4 of FIGURE 2, showing the coolant connections for the tension rod shown in FIGURE 2;

FIGURE 5 is a plan view, viewed in the direction of line 5--5 in FIGURE 1, showing the end clamps for the tension members extending across the roof of the battery of FIGURE 1;

FIGURE 6 is a plan view, viewed in the direction of line 6-6 in FIGURE 1, showing the jack structure for prestressing the tension members extending across the battery roof;

FIGURE 7 is a vertical section taken along the line 7--7 in FIGURE 6; and

FIGURE 8 is a diagrammatic plan view of a preferred arrangement of tensioning members positionedon the roof of the battery.

The coke oven battery shown in FIGURES 1 and 2 comprises a masonry structure built on a deck slab 11, which structure includes alternate coking chambers V12 separated by heating'walls 13 and having beneath the soles 14 of the coking chambers 12 a regenerator section 15. The regenerator section includes crosswise extending regenerators separated by regenerator division Walls in the customary manner. The masonry structure of the battery is completed by a roof 16 supported above the coking chamber across the entire length and breadth of the battery. As conventional, the usual charging holes 20 extend through the roof 16. l

The heating Walls are `composed of silica brick arranged to define heating ilues, which ues are provided with the usual burners to which fuel gas is supplied and which communicate with the regenerators in the regenerator section 15 for inllow of air or air and lean fuel gas and outflow of products of combustion. Since the present invention is applicable to all coke oven batteriesjmodied as described hereinafter, to minimize crack formation in the heating walls when the heating walls are heated to or cooled down from operating temperature, irrespective of the particular design of the heating walls, coking chambers, regenerators or other associated known parts, further description of these known battery elements is believed unnecessary.

Vertical buckstays 17 and 18, in the form of one or more .I-bearns or channel bars, are arranged at the opposide ends of each heating wall 13. In the Vform of the battery shown in the drawings, .individual buckstays 1'7 are disposed on the coke side, and similar buckstays 18 on the pusher side of the battery. Each -buokstay extends the full height of the battery, bearing against the adjacent heating wall 13 land regenerator division Wall therebeneath and exerting a compressive force against the C? masonry brickwork toward the longitudinal median of the battery. As conventional, side benches 19 are mounted along the length of and on opposite sides of the battery, secured to the respective buckstays 17 and 1S.

Doors

21 and 22 of any known type are provided in the opposite ends of each coking chamber to clos-e the ends of the coking chamber during coking, and to open same for movement of the pusher through the coking chamber, and discharge of coke at the coke side of the battery. These doors are provided with an opening 24 in the base thereof, which opening 24 is positioned just below the refractory plug of the door or can extend through this plug, as shown in FIGURE 2.

In accordance with this invention, when cooling down the battery, a tension member or rod 23 is positioned in each coking chamber near the base thereof, with its opposite ends projecting outwardly of the ends of the coking chamber through the openings 24. One end 25 of each tension rod 23 extends outwardly of and between a pair of the adjacent buckstays 17 at the coke side of the battery, and the opposite end 26 of each such rod extends outwardly of and between the adjacent buckstays 18 at the pusher side of the battery.

A pair of parallel elongated beams 27 (FIGURES 2 and 3) extend along the length of the coke side of the lbattery kengaging filler or blocking members 28 which bear against the outer fianges of the buckstays 17. Beams A=27 can be of any desired length exceeding the distance between the vertical axis of two adjacent buckstays; a suflicient number of shorter beams, each of desired length, may be provided to provide supporting beams between adjacent buckstays along the full length of the battery. The blocking ymembers 28 are dimensioned to compensate for misalignment and distortion of the buckstays 17 which may occur in batteries which have been in operation -for .a considerable period. The beams 27 engage and bear against their respective blocking members 2S along the length of the battery, providing a supporting surface on the outer surface of beams 27, which surface is a vertical plane parallel to the plane defining the adjacent side of the battery.

-Fastened to this supporting surface, -as by welding, is a pair of rails 29 having an apertured plate 31 suitably secured thereto. These rails are positioned opposite the base of each coking chamber. The end 25 `of each tension rod passes between the individual members of the pair of beams 27 and the pair of rails 29 and through the apertured plate 31. A clamping wedge 32 received in a supporting plate 33 is mounted on the end 25 outwardly of and in bearing relation against the apertured plate 31. Fixed to the end 25 of the tension rod adjacent the wedge 32 is an end clamp 34. The above described structure provides for a fixed clamp for end 25 of each tension rod 23, i.e., fixed relative to the coking chamber` from which end 25 protrudes. It will be appreciated that while the clamp Ydescribed is preferred, any available clamp can be employed for securely fixing one end of each of tension rods 23 relative to the coking chamber from which it protrudes.

Extending along the length of the pusher side of the battery is a suitable support for the jack employed to tension the tension rod 23. vIn the embodiment shown in the drawing, this support comprises upper and lower elongated beams l35 engaging blocking members 36 which bear against the outer iianges of the buckstays 18 and, like the blocking members 28,-compensate for any misalignment or distortion of the buckstays during operation prior to the cooling down of the battery. Fastened to beams 35 intermediate each pair of adjacent buckstays 18 are a pair of rails 37 having an apertured plate 38 suitably secured thereto. The end 26 of each tension rod passes between the beams 35 and the rails 37 and through the apertured plate 38.

A hydraulic tensioning jack 391s sequentially mounted on the end 26 of each tension rod toV place 4the tension iii rod under tension, thereby creating compressive forces against the buckstays v17 and 18 on opposite sides of the battery, as will be described more fully hereinafter. The tensioning jack includes a pulling wedge 41 secured to the end 26 of the tensioning rod 23. This pulling wedge 41 sits in a pulling head 42, e.g., a block or cylinder having an axial opening through which the tension rod 23 passes. Head 42 is actuated by a ram 43 which is a fiuid pressure cylinder of a known type having a piston 43' therein. This piston is actuated by pressure fiuid supplied from any suitable source such as Ia compressor, pump or accumulator. Piston 43 has a hollow piston rod R extending from the opposite sides thereof through the end walls of the cylinder. One end of this piston rod bears on and actuates the pulling head 42. The other end ybears on and actuates a seating ram 46 which, like the pulling head 42, is a block or cylinder having an axial opening through which the tension rod 23 passes. The seating ram 46 bears against and actuates an anchoring wedge 44 disposed in a wedge anchoring plate 45 mounted on apertured plate 38.

Ram 43 is provided with ports P and P on opposite sides of the piston 43 as shown in FIGURE 2. When pressure liuid is applied to port P and exhausted from port P' pulling head 42 is actuated to stress tension rod 23 to the desired extent. As tension is exerted on the pulling head 42 by the piston rod R, tension on end 26 yof tension rod 23 is correspondingly increased due to the cooperative wedgng action between the pulling wedge 41 and the pulling head 42, as shown in dotted lines on FIG- URE 2; the end 26 of tension rod 23 is firmly clamped throughout tensioning or retensioning of end 26 of tension rod 23. Once this rod 23 has been tensioned to the desired extent, the anchoring wedge 44, which had previously been .adjusted to permit movement of the tension rod v23 therethrough during the tensioning thereof, is positioned to clamp the tension rod 23. The anchoring Wedge 44 cooperates with the wedge-shaped opening in the anchoring plate 45 so that as the wedge 44 is moved to the left, viewing FIGURE 2, the clamping pressure on the tension rod 23 is increased by the wedging action of the cooperating members 44 and 45. After the anchoring wedge 44 has been seated in the wedge anchoring plate 4S, it can be driven home to securely maintain rod 23 `in the tensioned condition by actuating pressure fluid cylinder ram 43 to apply pressure fluid to port P and exhaust the pressure fluid from port P, thus causing the piston rod R on the left lhand side of the piston 43- (viewing FIGURE 2) to actuate the anchoring wedge 44 to firmly seat it within the cooperating .anchoring plate 45.l

The above description of the hydraulic tensioning jack 39 and the showing thereof in the drawings is exemplary of Ione known type of hydraulic tensioning jack. It will be understood that any commercially available jack or tension member can be used to apply the desired tension to elach tension rod 23 which preferably is of high strength stee The tensioning of tension rod 23, as hereinabove described, by -the tensioning jack 39 results in compressive forces on the -oppos-itely disposed buclrstay-s 17 and 18 exerted `from end 25 of the tension rod 23 which is securely held by the wedge 32 and cooperating plate 33 through plate 311, rails 29, fbeams 27, and blocking members 28 `against the outer tiange 4of the buckstay l17 on the coke side of the battery, and through plate 38, rails 37, beams 35 and blocking members 36 bearing against the outer iianges of the buckstays 18 on the pusher side of the battery. Thereafter the tensioning jack 39 is removed from the end 26 of the tension rod, the wedge 44 anchoring the rod in its tensioned position to maintain the compressive forces exerted against buckstays 17 and d8. The tensioning jack is then, in sequence, mounted on each of the tension rods 23 extending through the coking chambers, and each -such rod is placed under tension in the manner described above, whereby each of the buckstays ,17 and 1S along the length of the battery is placed under compressive forces which press the battery masonry structure inwardly tow-ard the longitudinal median thereof. Desirably, the compressive force thus exerted on each buckstay is of the order of from `about 50,000 to 100,000 pounds; the force employed will depend on the lwidth of the battery and the condition of the brickwork, For a baL ery 40 feet wide or wider, the buckstays 17 and 18 at the opposite ends of the hea-ting Walls adjacent the coking chambers at the ends of the battery preferably are placed under compressive forces of about 90,000 pounds, and the buckstays 17 and 1S at the ends of the intermediate heating walls are placed under compressive forces of about 60,000 pounds.

The -tensioning of the rods, `as hereinabove described, takes place throughout the period required for cooling down the battery, i.e., as the battery cools down and contracts, reducing the compressive forces under which the opposite sides of the battery have `been placed, the rods 23 in succession are again acted on by the jacks, successively, to restore the tension and maintain the compressive forces on the buckstays at the opposite sides of the battery at the desired level.

The time elapsed lbetween successive retensioning of the tension rods 23 will depend on the stage and rate of cooling, as described more fully hereinafter. In all cases the retensioning is effected whenever appreciable contraction of the brickwork takes place to restore the compressive Iforces on the buckstays at the opposite sides of the battery to maintain the brickwork at all times under substantially constant pressure (iluctuating Within a narrow range) from the opposite sides of the battery tov/ard the longitudinal median to close up cracks and fissures which form during the cooling.

The ytension rods 23 are mounted within coo-ling tubes 47 (FIGURES v2 and 4) which extend through the co-king chambers v12 and outwardly thereof through the openings 24. As best shown in "FIGUR-E 4, the end 4S of each cooling tube 47 extending outwardly of the battery intermediate the .buckstays 18 on the pusher Side thereof has a T 49 adjacent the packing gland 51 through which the tension rod 23 extends. T 49 is connected through a valve controlled conduit 52 with .supply header 55 (FIG- URES l yand 4) extending along the length of the battery and communicating with each or" the cooling tubes 47. Cooling Water from any suitable source is supplied to header 55.

The opposite lend 56 of each cooling tube is connected to a drain header 57 (FIGURE ll) extending along the length of the opposite side of the battery `and connected to each cooling tube 47 at the T 54 (FIGURE 2). End 56 -is provided with .a packed construction similar to packing gland 51 for the end 25 of the :tension rod passing therethrough. Dnain header S7 may communicate with a sewer or a circulation system provided with a cooler for cooling and recirculating the cooled Water or other cooling fluid through the cooling tubes 47.

Customary battery construction involves tie rods 90 Iin the roof of the battery, usually -two tie rods for each heating wall. The tie r-odshave at `one or both ends eavy compression springs *91. The compressive force exerted by these springs can be .adjusted by nuts 92. At the bases of the buckstays, anchor bolts 93 are provided equipped with heavy compression springs 94, The pressure exerted by these springs can be adjusted by nuts 95 on the ends of anchor bolts 93. For many batteries, particularly batteries containing small ovens having a length less than 40 feet and a height of l2 feet or less, tensioning of the cooled tension rods, as hereinabove described, supplemented if necessary by adjustment of the springs on the tie rods and anchor bolts during the cooling down of the battery will suffice to eiect such cool-ing without excessive cracking of the brickwork of the heating Walls and regenerator division walls taking place.

lFor batteries of larger ovens and for all batteries, if

desired, and where caution dictates, auxiliary tensionproducing struc-ture on the roof of the battery, which structure is indicated generally at 5S, is provided associated lwith each pair of oppositely disposed buckstays 17 and 13. In the case of underjet ovens where the base portion of the battery is accessible through the basement space, a tension-producing structure Y (FIGURE l) similar to 5S can also be employed.

In the embodiment of the invention sh-own in FIG- URE 6 of the drawings, the tension-producing structure S8 includes four tension members for each pair of buckstays at the opposite sides of the battery, two extending from the pusher side and two extending from the coke side an-d suitably interconnected, as hereinafter described, `at a point on the roof of the battery to apply compressive forces to the opposite sides of the roof of the battery. Employing tour tension members, as shown in FIGURES l, 5, 6 and 7, in association with each pair of buckstays 17 and 10, 'two spaced members or tendons 59 extend from the coke side of lthe battery Where one end of each is suitably clamped or anchored, as hereinafter described, on the opposite sides of buckstays 17 and two spaced tendons 60 extend from the pusher side of the battery, where `one end of each is suitably clamped or anchored, as hereinafter described, on the opposite .sides of buckstays 18.

The opposite ends of the

tendons

59 and 60 are suitably anchored to wedge anchors, hereinafter described, positioned at any desired point on the roof of the battery between the sides of the battery, which wedge anchors can be actuated by hydraulic jacks or other suitable tension applying members to pull the tendons from the opposite sides of the battery towards each other and thus apply compressive forces to the opposite sides of the upper portion of the battery towards the longitudinal median thereof. One such assembly for one pair of oppositely disposed buckstays 17 and 13 will now be described in greater detail. It will be understood that each pair of oppositely disposed buckstays is provided with such assembly.

An apertured supporting member 61 (FIGURE 5) is suitably secured to the outer flange of each buckstay 18. Member 61 has a pair of apertured wedge anchoring plates 62 secured thereto. Ends 63 of the tendons 60 pass through the anchoring plates 62 and have anchoring wedges 64 thereon, seated against the anchoring plates. Fixed to the ends 63 of tendons 60 adjacent the Wedges 64 are end clamps 65. The ends of tendons 59 at the opposite side of the battery are similarly anchored to the buckstay 17. This anchor structure can be of any known type for securely anchoring the ends of the tendons S9 and 60 to buckstays 17 and 1S, respectively.

A pair of hydraulic tension jacks 66, .each preferably of the same type as jack 39 shown in FIGURE 2, are mounted in sequence, on ends 67 of each pair of tendons 60, adjacent the longitudinal median or other desired intermediate point on the roof of the battery. Each jack 66 bears against an apertured plate 68 suitably secured, as by Welding, to a pair of rails 69 (see FIGURES 6 and 7). Each jack includes a pulling wedge 70 secured to the end 67 of the tendon 60, which wedge is subjected to the force exerted by a pulling head 71 actuated by a hydraulic tensioning ram 72, which has a piston and piston rod construction similar to piston 43 and piston rod R of ram 43 hereinabove described. Adjacent the right hand end of the jack66, viewing FIGURE 6, au anchoring wedge 73 mounted on the tension rod 60 is seated in a wedge anchoring plate 74, bearing against the apertured plate 68. A hydraulic wedge seating ram 75 of the tension jack 66 forces the wedge 73 into engagement with the'anchoring plate 74.

Each tendon 59 has its end 76 passing through an apertured plate 77 bearing against the rails 69. A wedgeV 70 seated in a wedge anchoring plate 79 is mounted on the end 76 of the tension rod, bearing against the aper- 7 tured plate 77. Fixed to the end 76 of the tension rod adjacent the wedge 78 is an end clamp 81.

Actuation of the pulling head 71 by the tensioning ram 72 causes the pulling wedge `70 to place the tendons under tension. After thus placing tendons 60 under tension, the wedge seating ram 75 of each tension jack is actuated to force the wedge 73, mounted on tendon 60, into seating engagement with anchoring plate 74, bearing against the apertured plate 68 to maintain the tension on tendons 60. The wedge seating ram of each jack also exerts a force on the apertured plate 58, rails 69, and the apertured plate 77, against the wedge anchoring plate 79 and the wedge 73 seated therein, which places the tendons 59 under a pulling force in the opposite direction from the pulling force on the tendons 60.

In the drawing, two jacks, each operated, as conventional, by pressure uid supplied by pumps, are employed, one for one set of

tendons

59 and 60, and the other for the other set, shown in FIGURE 6, associated with each pair of oppositely disposed buckstays. Once the jacks have placed the respective tendons under tension exerting the desired compressive forces on the buckstays on the opposite sides. of the battery, which tension is held by the holding wedges, the jacks are moved to another tension-producing structure 5S where the jacks are used to place the

tendons

59 and 60 under desired tension. This tension is adjusted from time to time during cooling in much the same manner hereinabove described for the adjustment of the tension imparted to the tension rods 23.

FIGURE 8 shows an alternative and preferred arrangement of tensioning members positioned on the roof of the battery between one pair of oppositely disposed buckstays 17 and 18. pair of oppositely disposed buckstays along the length of the battery are provided with a similar tensioning construction. In FIGURE 8 the buckstays 17 and 1S have secured thereto blocking members 28 and 36', respectively, which have the same function as the correspond-`

ving members

28 and 36 hereinabove described. Beams 96, 97 are suitably fastened to the blocking members 28' and 36', respectively. A yoke 99 has the ends 101, 102 suitably clamped to the beam 96 and the `opposite ends 99' joined by a cross-beam 125. Gne end of tensioning member 98 is suitably fastened to the cross-beam and the other end 103 extends through a jack 104, desirably of the same type as the jack 39 hereinabove described. This jack has a holding wedge 105 for securely holding end 103 of the tensioning member 98 when the latter has been suitably tensioned by the jack 104. End 103 of tensioning member 98 extends within a frame 106 suitably disposed at any desired intermediate point of the width of the battery, say, at about the longitudinal median of the battery. This frame is constituted of rods 107 and 108 connected 'by the connecting

members

109, 110 forming a rigid frame within which the jack 104 is positioned when it is desired to tension or retension the tensioning structure associated with each pair of buckstays on opposite sides of the battery. Secured to frame 105 is end 111 of a tensioning member 112 fastened to a cross-bar 112 to which one end of yoke 113 is also fastened. The ends 114 and 115 of the yoke 113 are securely fastened to beam 97 Vbearing against blocking member 36'.

When tension is applied to the tensioning member 98 in a direction to shorten this tension member by a jack 104 and the end 103 is held in the tensioned condition by the holding wedge 105, the net result is that compressive forces are applied to the buckstays 17 and 18 on the opposite sides of the battery utilizing the single jack 104 for this purpose. After the pair of buckstays 17 and 18 have been placed under the desired tension by the

tensioning members

98, 112 as hereinabove described,

It will be understood that each 8 the jack 104 is removed and used on an adjoining ten-v sioning structure similar to that shown in FIGURE 8 to adjust the forces exerted thereby on the buckstays 17, 18, associated therewith. As in the modification of FIG- URES 5, 6 and 7, the above described action is repeated during the cooling down or heating up to apply to the upper ends of the buckstays the desired tension resulting in the compressive forces on the upper portion of the battery from the opposite sides toward the longitudinal median, which minimize, if not prevent, crack formation in the upper portion of the battery and the closing up of any cracks which form.

It will be noted that the structu-re `of FIGURE 8 differs from that of FIGURES 5, 6 and 7 chiefly :in that it involves a pair of

tensioning members

98, 112 instead of the four

members

59 and 60, and further that it employs one jack for effecting tensioning of these tension members rather than the pair of jacks 66.

The tensioning structure for the base portion of the battery can be of the type shown in FIGURE 8 or FIG- URES 5, 6 and 7. In FIGURE 1 is shown a tensioning member comprising rods 98' and 112 similar to

rods

98 and 112, the ends 120 of which Iare suitably clamped to the buckstays 17 land 18 desirably by yokes having an intervening blocking member similar to 28 and 36 of FIGURE 8. There is, of course, one such tensioning member for each pair of buckstays 17, 18 at the opposite sides of the battery. At a point intermediate the ends of each tension member 120, a frame structure 106 similar to frame 106 is positioned. This structure is arranged to receive a tension jack similar to jack 104 `of FIGURE 8 for tensioning member 120 in substantially the same manner as hereinabove described in connection with

tensioning rods

98, 112.

In the case of other types of batteries having large ovens which, unlike an underjet oven battery, do not permit ready access to the lower portion of the battery, the pressure exerted by the heavy springs 94 on the anchor bolts 93 at the base of the battery can be adjusted by the nuts 95 to control the pressure exerted on the lower ends of the buckstays. Instead of having the springs 94 positioned at the inner ends of the anchor bolts 93 as shown in FIGURE l, the springs may be disposed so that they bear directly on the lower ends of the buckstays.

When cooling down a coke oven battery in accordance with this inventionfrom operating temperature (about 2600 F.) to atmospheric ambient temperatures, no special precautions need be taken during the initial cooling to about 1800" F. because during this cooling no contraction of the brickwork takes place. This initial cooling is readily effected by lreducing the amount of heating gas burned in the flues gradually to reduce the heat input to the battery. As soon as a temperature of 1800 F. is reached the tension rods 23 within the cooling jackets or tubes 47 are placed in the cok'ing chambers and the rods maintained at a temperature below 212 F., at least during the stages of the cooling down when the tension rods would be deleteriously affected by high temperatures, by circulating cooling water or other cooling medium through the tubes 47 to maintain the tension rods at such temperature that they can be placed under tension and they will retain the tension under which they are placed to exert through the buckstays the desired compressive forces at the sides of the battery. The hydraulic tension jacks 39 and 66 are employed to place tension rods 23 and the tension members 5S and 120, if used, under tension, and adjust the tension from time to time, as needed, to exert compressive forces through the buckstays 17 and 18 on opposite ends of the heating walls and regenerator partition walls of the battery.`

The forces thus exerted through the buckstays towards the longitudinal median of the battery are maintained substantially constant as the battery is slowly cooled down from the operating temperature to the ambient temperature. Cooling is eifected by gradually reducing the 9 amount of gas burned in the tlues; when cooling from l400 to about 600 F., gas is burned in only the end ues of the battery. Thereafter no gas is burned in any of the flues.

Cooling of the battery lis carried out at a controlled rate, which rate changes as the battery cools down. The rate of cooling is more rapid in the 18000 to 800 F. range than in the 800 to 200 F. range. In the latter ranges the greatest contraction of the silica brick takes place and hence it is important to cool at a slower rate. Throughout the cooling down of the battery, the rate of cool-ing is controlled to obtain substantially the same amount of contraction per day. Operating in this manner, retensioning of the rods 23 once a day will suiiice. For most colte oven batteries now in use such cooling requires about two weeks to cool the battery from operating temperature to l800 F., and about iive weeks to cool the battery from l800 to 100 F. Cooling below about 800 F. should preferably be at a rate of about nine days to effect cooling from 800 to 400 F.; twelve days to effect cooling from 400 to 200 F.; and seven days to effect cooling to ambient atmospheric conditions.

During the cooling process the

hydraulic jacks

39 and 66 or 104 Iare adjusted about once a day to take into account the contraction of the `silica bricltwork; as noted, the rate of cooling is regulated to give approximately the same amount of contraction per day.

Periodically, say about once each three or four days, the compressive forces applied to the buckstays 17 and 18 by means of the tension rods 23 and the tension members S8 are released momentarily in order to compensate for vertical shrinkage of the battery brickworlc and allow the upper portions of the briclrwork to settle downward by gravity, thus avoiding arching of the upper portions of the heating walls. Immediately after such momentary release of the pressure, it is reapplied. The battery is thus cooled down without excessive crack formation in the heating walls which heretofore has resulted in loss of the battery or diminution of :its useful life and yoperating eiiiciency.

Since various modifications in the process of cooling down the coke oven battery shown in the drawings `and described herein will occur to those skilled -in the art, all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. The process of cooling down a regenerative coke oven battery 4constituted of refractory brickwork defining the heating walls and coking chambers in side by side relation with crosswise extending regenerators beneath the heating walls defined by regenerator division walls positioned beneath the heating Walls, said regenerative coke oven battery having buckstays at the opposite sides of each heating wall and the regenerator division Wall therebeneath and having tie rods extending across the top of the battery with at least one tie rod positioned at the top of each heating wall, means at the ends of the tie rods for applying compressive forces on the opposite ends of each heating wall, means at the base of the regenerator division Walls for 'applying compressive forces to the opposite ends thereof toward the median of the battery, which process comprises placing a tension member in each coking chamber of the battery near the base of the coking chamber with the ends thereof extending exteriorly of the coking chamber, securing the ends of each of the tension members to the buckstays at the opposite sides of the battery, applying a tensioning force to at least one end of each tension member to tension said tension member and maintaining said tension to thereby exert compressive forces on the buckstays from the opposite sides of the battery toward the longitudinal median thereof, cooling the tension members during the application of the compressive forces and periodically adjusting (a) the tension applied to each tension member during the cooling yof the battery, (b) the means at the ends of the tie rods for applying compressive forces 4on the opposite ends of each heating wall, and (c) the means at the base of the regenerator division Walls for applying compressive force to the opposite ends thereof to maintain the opposite sides of the battery under substantially constant compressive forces toward the longitudinal median of the battery notwithstanding contraction of the briclrwork during the cooling of the battery, thus minimizing formation of cracks in the battery during the cooling thereof and closing up cracks which form.

2. in a process of cooling down a regenerative coke oven battery constituted of refractory brickwork and having buckstays at the opposite sides thereof involving passing tension members through the coking chambers of the battery, securing one end of each of said tension members to the buckstays at one `side of the battery, placing the other end of each of said tension members under tension to thereby exert compressive forces on the buckstays from the opposite sides of the battery toward the longitudinal median thereof, cooling said tension members during the application of 4said compressive forces, and adjusting the tension applied to said tension members during the cooling of the battery from time to time to maintain the opposite sides of said battery under substantially constant compressive forces toward the longitudinal median of the battery and thus minimize formation of cracks in the battery and close up cracks which form, the improvement which comprises periodically momentarily releasing the tension applied to the tension members during the cooling of the battery to allow for Vertical shrinkage of the .battery brickwork and permit the upper portions thereof to settle by gravity, thus minimizing arching of the upper portions of the battery brickwork.

References Cited by the Examiner UNITED STATES PATENTS 1,259,133 3/ 18 Roberts 202-223 2,147,681 2/ 39 Van Ackeren 202-268 2,812,293 1l/57 Van Ackeren 202-268 2,978,386 4/ 61 MacDonnell et al. 202,-1

FOREIGN PATENTS 295,885 8/ 28 Great Britain.

428,268 5/35 Great Britain.

643,982 4/ 37 Germany.

507,575 6/39 Great Britain.

566,996 1/ 45 Great Britain.

667,566 3/52 Great Britain.

155,756 3/ 54 Australia.

862,287 3/ 61 Great Britain.

Price: Controlled Cooling of a Koppers-Becker Battery, Blast Furnace and Steel Plant, Feb. 1951, pp. 203-213.

MORRIS O. WOLK, Primary Examiner.

Claims

1. THE PROCESS OF COOLING DOWN A REGENERATIVE COKE OVEN BATTERY CONSTITUTED OF REFRACTORY BRICKWORK DEFINING THE HEATING WALLS AND COKING CHAMBERS IN SIDE BY SIDE RELATION WITH CROSSWISE EXTENDING REGENERATORS BENEATH THE HEATING WALLS DEFINED BY REGENERATOR DIVISION WALLS POSITIONED BENEATH THE HEATING WALLS, SAID REGENERATIVE COKE OVEN BATTERY HAVING BUCKSTAYS AT THE OPPOSITE SIDES OF EACH HEATING WALL AND THE REGENERATOR DIVISION WALL THEREBENEATH AND HAVING TIE RODS EXTENDING ACROSS THE TOP OF THE BATTERY WITH AT LEAST ONE TIE ROD POSITIONED AT THE TOP OF EACH HEATING WALL, MEANS AT THE ENDS OF THE TIE RODS FOR APPLYING COMPRESSIVE FORCES ON THE OPPOSITE ENDS OF EACH HEATING WALL, MEANS AT THE BASE OF THE REGENERATOR DIVISION WALLS FOR APPLYING COMPRESSIVE FORCES TO THE OPPOSITE ENDS THEREOF TOWARD THE MEDIAN OF THE BATTERY, WHICH PROCESS COMPRISES PLACING A TENSION MEMBER IN EACH COKING CHAMBER OF THE BATTERY NEAR THE BASE OF THE COKING CHAMBER WITH THE ENDS THEREOF EXTENDING EXTERIORLY OF THE COKING CHAMBER, SECURING THE ENDS OF EACH OF THE TENSION MEMBERS TO THE BUCKSTAYS AT THE OPPOSITE SIDES OF THE BATTERY, APPLYING A TENSION FORCE TO AT LEAST ONE END OF EACH TENSION MEMBER TO TENSION SAID TENSION MEMBER AND MAINTAINING SAID TENSION TO THEREBY EXERT COMPRESSIVE FORCES ON THE BUCKSTAYS FROM THE OPPOSITE SIDES