US 3917516 A
A coke-cooling apparatus comprises a drum rotatable in a bath of cooling water about a generally horizontal axis and traversed from end to end by the coke to be cooled. The wall thickness of the drum or shell increases progressively from a central region toward each end.
Description (OCR text may contain errors)
4 United States Patent Waldmann et a1.
COKE-COOLING APPARATUS Inventors: Hans Waldmann, Trostberg;
Wilfried Schwarz, Wald Kraiburg; Manfred Bergfeld, Tacherting; Hans Joachim Laupitz, Burghausen; Klaus Miiller, Mehring; Thaddeus J. Oleszko, Burghausen, all of Germany Linde Aktiengesellschaft, l-lollriegelskreuth, Germany Filed: Mar. 21, 1974 Appl. No.: 453,547
Foreign Application Priority Data Mar. 26, 1973 Germany 2315024 US. Cl. 202/227; 165/90; 34/9;
34/134; 432/80; 432/85 Int. Cl Cl0b 39/00 Field of Search 165/87-90;
Primary Examiner-Charles .1. Myhre Assistant Examiner-Theophil W. Streule Attorney, Agent, or Firm-Karl F. Ross; Herbert Dubno  ABSTRACT A coke-cooling apparatus comprises a drum rotatable in a bath of cooling water about a generally horizontal axis and traversed from end to end by the coke to be cooled. The wall thickness of the drum or shell in creases progressively from a central region toward each end.
9 Claims, 4 Drawing Figures aaauuuuuabuuuu Sheet 1 of2 US. Patent Nov. 4, 1975 J. DQQIADBDDBQD [Z 5 BBQ US. Patent Nov. 4, 1975 Sheet 2 of2 3,917,516.
COKE-COOLING APPARATUS FIELD OF THE INVENTION The present invention relates to a coke-cooling apparatus and, more particularly, to an apparatus for cooling bulk material, especially coke, by indirect heat exchange with a coolant such as water.
BACKGROUND OF THE INVENTION The cooling of coke from a glowing state, as this hot bulk material is received from a coke oven, has been effected in the past in apparatus which carries out an indirect heat exchange between the coke and a coolant, especially water, through the wall of a drum rotatable about a horizontal axis and axially traversed by the hot coke from an inlet end to an outlet end of the drum.
The drum is rotatable in a bath of water and it is formed with tubular pockets which increase the surface area in contact with the coke and the water and entrain the water from the bath so that it flows substantially over the entire external surface of the rotating drum.
In conventional rotary coolers, the rotor drum or shell (also generically described in the art as the socalled rotor) is of polygonal cross-section, usually with eight sides.
Because of the high temperatures of the coke, the shell is subjected to substantial temperature differentials not only between its exterior and interior but from one end to the other, which causes rapid wear and deterioration of the shell walls and the walls of the tubular pocket across which the coke must pass. The thermal stresses limit the life of the apparatus and replacement of the drum is relatively expensive and results in significant downtime of the system. Consequently, continuous operation of the apparatus is seldom possible.
OBJECTS OF THE INVENTION It is the principal object of the present invention to provide an apparatus for the cooling of coke or other bulk material in indirect heat exchange with a fluid coolant, especially water, in which deterioration of the vessel containing the bulk material is limited and the useful life of the apparatus is increased beyond those of the prior art.
Another object of the invention is to provide a coke cooler of the general type described previously which has a longer useful life and a greater ratio of operating time to downtime.
Still another object of the invention is to provide a coke cooler of relatively low cost but improved efficiency.
SUMMARY OF THE INVENTION These objects and other which will become apparent hereinafter are attained in accordance with the present invention, in a cooler for bulk material, especially coke, which comprises an outer housing or vessel adapted to receive a bath of liquid coolant, preferably water, and a drum, rotor or shell of generally prismatic or polygonal-cross-sectional configuration in this vessel and rotatable about a horizontal axis, the drum having an inlet end into which the bulk material is charged and an outlet end from which the cooled material is discharged. According to the present invention, the rotor or drum comprises a sheet-metal shell of progressively increasing wall thickness from an intermediate region along its length toward the inlet and outlet ends.
According to another feature of the invention, the rotor, drum or shell is provided with a multiplicity of inwardly extending tubular pockets of sheet-metal, e.g., sheet steel, which pick up, conduct and distribute the coolant over the periphery of the drum and increase the cooling effectiveness, the wall thicknesses of these tubular pockets likewise increasing progressively from the intermediate region of the drum toward its ends.
The invention has been found to be surprisingly ef fective in increasing the useful life of the drum or rotor because the increased material thicknesses towards the ends compensate for the increased wear in these regions. For example, the wear at the inlet end at which the glowing coke is introduced at an extremely high temperature, e.g., 1,400C is proportionally higher because of the thermal stress and the corrosive effect of the hot bulk material than at "the intermediate regions in which the coke has been cooled to a significant degree. However as cooling progresses, the hardness of the coke increases and toward the end of the drum the abrasive character of the material is significantly increased over its abrasive effect at the temperatures of the intermediate region or zone so that the increased material thicknesses at this end likewise compensate for material wear. At the outlet the temperature of the coke may be relatively low, e.g., C, although the hardness and abrasive character of the coke may be several times greater than that of the coke at the higher temperatures upstream in the drum.
Since the thickness of the drum is proportioned to the wear rates at the various regions along the length of the drum, the useful life of the drum is increased since wear to failure occurs uniformly across the drum length.
It has been found that this effect can be increased when, from the inlet end of the rotor or drum to the outlet end thereof, the radial height of the tubular pocket is increased and their facing is likewise increased while the widths of the pockets (parallel to the axis of the drum) is decreased.
The smaller interpocket distances (closer spacing) and the wider construction of the pockets makes for a greater density of heat exchange area per unit of axial length of the drum at the inlet end and hence an increased heat exchange capacity at the regions at which the temperature is higher. Furthermore, the low height of the pockets in the region of the inlet insures a more uniform distribution of the bulk material over the interior of the drum and a more complete immersion of the pockets in the water bath, again increasing the heat exchange properties of the drum in this region. It has been found advantageous, for a unifrom cooling of the shell, to provide the inlet end or outlet of the cooling pocket with shiftable covers which limit the throughflow of coolant and thereby permit a uniform temperature gradient to be maintained over the length of the drum and prevent thermal stresses which result from significant temperature differentials and promote wear.
Since the tubular cooling pockets within thedrum come into direct contact with hot or cooled coke and sufficient or abrasive hard coke, it has been found to be advantageous to protect the surfaces of the cooling pockets turned toward the axis of the drum with protective aprons or copings. The latter may be composed of steel and may be angles or steel plates which, to avoid the effect of thermal stress, are secured at single points in the middle of each plate section to the cooling pocket.
Because of the relatively considerable mass of the rotor and the coke traversing same it has been found to be advantageous to avoid the development of stress at the cooling pockets and elsewhere in the drum by distributing the bulk material uniformly over the interior of the drum. This is effected, according to the invention, by providing the inlet of the drum as a conically widening shell which may be formed with a plurality of cooling pockets which also act to promote the advance of the material into the interior of the drum mentioned as do advance in a conventional bulk-material treatment device.
BRIEF DESCRIPTION OF THE DRAWING The above and other objects, features and advantages of the present invention will become more readily apparent from the following description, reference being made to the accompanying drawing in which:
FIG. 1 is a diagrammatic vertical section wherein, because of the small size of the drawing, wall thicknesses have not been shown;
FIG. 2 is a section taken along the line IIII of FIG. 1 and drawn to an enlarged scale;
FIG. 3 is a detail cross-section view through a portion of the drum of FIG. 1 showing the relationships of the wall thickness and cooling pockets to the drum in greater detail; and
FIG. 4 is an elevational view of the portion of the drum, drawn to a larger scale than FIGS. 1 and 2.
SPECIFIC DESCRIPTION The coke cooler shown in the drawing comprises a vessel 1 for water bath 3 receiving a rotor or drum 2 of octagonal cross-section (see FIG. 2).
The rotor or drum 2 dips into the water 3 to a substantial extent, i.e., the greater part of the radius of the drum which may also be cylindrical or of another polygonal cross-section as desired.
The rotor or drum 2 comprises an outer shell 6 having a horizontal axis and formed at one end with a discharge duct 6 and the opposite end with a conical inlet duct frustoconically diverging in the direction of the drum 2. At this duct 5 there are provided a plurality of chordal cooling pockets 7 which permit intensive cooling by contact with the water bath and limit the formation of thermal stresses and cracking between the drum and the inlet duct 5. The inlet duct 5 and the outlet duct 6 can be flanged as shown for the duct 5 or welded as shown in duct 6, to the drum.
Ahead of the inlet duct there is provided a water cooled inlet chute 8 which leads the coke from the coke furnace into the inlet duct, the chute representing inlet means, etc., according to the principles of the present invention. 1
The discharge duct 6 is provided with discharge means for drawing the bulk material from the system in the form of a conveyor wall which opens into a discharge chamber or hopper 9 which may be composed in whole or in part of wire-reinforced glass and is provided with an automatically operable emergency door .11 for relieving pressure within the system, e.g., in the case of explosion or the development of a gas condition. The door 11 may by hydraulically operable.
When a greater heat exchange area is desired, the level of the water bath 3 can be raised and, when a reduced heat exchange capacity is desired, the water bath level may be lowered. To permit raising and lowering of the level beyond the region in which the drum is jour- 4 naled, the rotor or drum 2 is rotatably sealed relative to the vessel 1 with sealing rings 12 or 13 of rubber or other material which permits rotation but prevents escape of water.
The drum 2 is formed with a multiplicity of tubular cooling pockets 14 which extend along chords of the device and open the opposite walls of the drum. The pockets thus lie transversely to the drum axis and can be sealed along the inner walls of the drum.
According to the invention, the sheet-metal thickness of the shell 4 and of the cooling pockets 14 increase from an intermediate region of the rotor 2 in the direction of the inlet 15 and the outlet 16. The height of the cooling pockets 14 perpendicular to the rotor axis and the spacing of the cooling pockets 14 from one another increase from the inlet to the outlet while the width of the cooling pockets decreases from the inlet to the outlet.
The open .ends of the cooling pockets l4 lie at the surface of the shell 4 and are provided with slidable covers 17 which permit control of the water flow through the pockets during rotation.
The arched side of the cooling pockets l4 turned toward the rotor axis are protected by angle members 18 of steel weld only at central locations to the cooling pockets. The welding locations are represented by dots 18 in FIG. 2.
Above the rotor, there is disposed a supply device 19 for promoting heat exchange and thereby reducing thermal stress while increasing the throughput of the apparatus. To reduce water loss, a dephlegmator 20 is provided in the vent to the vessel 1 for condensation of water from the gas phase above the water bath.
Further cooling of coke, the glowing bulk product is introduced through the inlet chute 8 and the inlet duct 5 to pass over the cooling pockets in the main portion of the drum 2 and subject the coke to indirect heat exchange with the water bath. The water passes through the pockets l4 and reduces the temperature of the coke so that cooled coke is withdrawn via the discharge duct 6 and the worm 10 to collect in the hopper 9. The rate of operation of the worm 10 controls the level of coke within the drum.
FIGS. 3 and 4 show the features of the invention in somewhat greater detail. From FIG. 3, for example, it will be apparent that the thickness of the shell 4 of the drum 2 decreases from a thickness T to a thickness t from the inlet end toward an intermediate region and a corresponding decrease in thickness takes place from the discharge end to the intermediate region. Described otherwise, the wall thickness of the steel shell 4 increases from the thickness t at an intermediate location L to a thickness T toward each end. The cooling pockets or tubes 14 which are welded at 14' to the wall 4 and along their peripheries 14" to the adjacent wall 4 of the shell, have widths measured parallel to the axis of rotation of the drum which decrease from a width W to, say a width w progressively from the inlet side to the discharge side of the drum.
The height of the cooling pockets or tubes 14, as measured radially with respect to the axis of rotation of the drum may increase from a height h to the height H, etc., progressively from the inlet side to the discharge side of the drum and the wall thicknesses of the pockets may decrease from the thickness 1 toward each end. The thicknesses of the protective angle members 18 may likewise decrease from a thickness t" to a thickness T" from the intermediate region toward each end of the drum. The single weld point for each flange 18a, 18b of the protective members 18 is represented at 18 in FIG. 3.
FIG. 4 was the opening at which the pockets communicate with the exterior in the walls 4' and 4" of the drum 4. These openings can be blocked completely or partly by the slidable plates 17 which are guided in channels 17' parallel to the axis of rotation of the drum and are movable as represented by the arrows to completely or partially overlie these openings.
The distance between the pockets 14 may increase from a relatively small distance d at the inlet end to larger distances D, etc., toward the discharge end of the drum (FIG. 3). The discharge worm may be vertically adjustable, i.e., of adjustable height, if desired to control the level of material in said drum.
What is claimed is:
1. In a coke-cooling apparatus for bulk material comprising a vessel forming a water bath, an elongated drum rotatable about a horizontal axis in said vessel and dipping into said water bath; the improvement comprising a multiplicity of tubular cooling pockets formed on the wall of said drums, said drum having a sheet-metal wall, the wall thickness of said drum and said cooling pockets increasing progressively from an intermediate region along the length of said drum toward the opposite ends thereof.
2. The apparatus defined in claim 1 wherein said cooling pockets are of increasing radial dimension as measured with respect to the axis of rotation of said drum and increasing inter-pocket spacing parallel to 6 the axis of the drum from an inlet end thereof toward a discharge end thereof, the width of said pockets as measured parallel to said axis decreasing from said inlet end toward said discharge end.
3. The apparatus defined in claim 2, further comprising slidable covers on said drum for controlling the fluid through-flow of said pockets.
4. The apparatus defined in claim 3 wherein said pockets have surfaces turned toward said axis, said surfaces turned toward said axis being provided with we arreducing aprons.
5. The apparatus defined in claim 4, further comprising a frustoconical inlet duct widening toward and communicating with said drum at said inlet end.
6. The apparatus defined in claim 5 wherein said inlet duct is provided along its periphery with a multiplicity of cooling pockets.
7. The apparatus defined in claim 6 wherein'said discharge end is provided with a discharge duct leading through said vessel, said ducts being sealedrelative to said vessel with respective sealing rings.
8. The apparatus defined in claim 4 wherein said discharge end communicates with a collection chamber for the cooled material, said collection chamber being formed with an automatic operable emergency door.
9. The apparatus defined in claim 4, further comprising a discharge wall at said discharge end for removing cooled material from said drum, said discharge wall being of adjustable height to control the level of materials in said drum.