Abstract:
Relatively high speed methods for increasing the bulk density of coal particles without impacting the coal particles and an apparatus for compacting coal for making metallurgical coke. The method includes depositing coal particles onto a charging plate external to a coking oven. The charging plate has side walls, and at least one movable end wall to provide an elongate bed of dry, uncompacted coal having an upper surface on the charging plate. The uncompacted coal is compacted by passing a vibratory cylindrical compactor along a length of the uncompacted coal for a number of passes sufficient to decrease a thickness of the bed of coal to less than about 80 percent of an original thickness of the uncompacted coal. The vibratory cylindrical compactor has a length to diameter ratio ranging from about 1.4:1 to about 2:1.

Description:
TECHNICAL FIELD 
       [0001]    The disclosure relates to a method and apparatus for making coke from coal and in particular to an improved method and apparatus for compacting coal for feed to a non-recovery coking oven. 
       BACKGROUND AND SUMMARY 
       [0002]    Coke is a solid carbon fuel and carbon source used to melt and reduce iron ore in the production of steel. During an iron-making process, iron ore, coke, heated air and limestone or other fluxes are fed into a blast furnace. The heated air causes combustion of the coke that provides heat and a source of carbon for reducing iron oxides to iron. Limestone or other fluxes may be added to react with and remove the acidic impurities, called slag, from the molten iron. The limestone-impurities float to the top of the molten iron and are skimmed off. 
         [0003]    In one process, known as the “Thompson Coking Process,” coke used for refining metal ores, as described above, is produced by batch feeding pulverized coal to an oven that is sealed and heated to very high temperatures for 24 to 48 hours under closely controlled atmospheric conditions. Coking ovens have been used for many years to covert coal into metallurgical coke. During the coking process, finely crushed coal is heated under controlled temperature conditions to devolatilize the coal and form a fused mass having a predetermined porosity and strength. Because the production of coke is a batch process, multiple coke ovens are operated simultaneously, hereinafter referred to as a “coke oven battery”. 
         [0004]    At the end of the coking cycle, the finished coke is removed from the oven and quenched with water. The cooled coke may be screened and loaded onto rail cars or trucks for shipment or later use or moved directly to an iron melting furnace. 
         [0005]    The melting and fusion process undergone by the coal particles during the heating process is the most important part of the coking process. The degree of melting and degree of assimilation of the coal particles into the molten mass determine the characteristics of the coke produced. In order to produce the strongest coke from a particular coal or coal blend, there is an optimum ratio of reactive to inert entities in the coal. The porosity and strength of the coke are important for the ore refining process and are determined by the coal source and/or method of coking. 
         [0006]    Coal particles or a blend of coal particles are charged into hot ovens on a predetermined schedule, and the coal is heated for a predetermined period of time in the ovens in order to remove volatiles from the resulting coke. The coking process is highly dependent on the oven design, the type of coal and conversion temperature used. Ovens are adjusted during the coking process so that each charge of coal is coked out in approximately the same amount of time. Once the coal is coked out, the coke is removed from the oven and quenched with water to cool it below its ignition temperature. The quenching operation must also be carefully controlled so that the coke does not absorb too much moisture. Once it is quenched, the coke is screened and loaded into rail cars or trucks for shipment. 
         [0007]    Because coal is fed into hot ovens, much of the coal feeding process is automated. In slot-type ovens, the coal is typically charged through slots or openings in the top of the ovens. Such ovens tend to be tall and narrow. More recently, horizontal non-recovery or heat recovery type coking ovens have been used to produce coke. Horizontal ovens are described for example in U.S. Pat. Nos. 3,784,034 and 4,067,462 to Thompson. In the non-recovery or heat recovery type coking ovens, conveyors are used to convey the coal particles horizontally into the ovens to provide an elongate bed of coal having a height of about 101 centimeters, a length of about 13.7 meters, and a width of about 3.6 meters. 
         [0008]    As the source of coal suitable for forming metallurgical coal has decreased, attempts have been made to blend weak or non-coking coals with coking coals to provide a suitable coal charge for the ovens. One attempt is to use compacted coal. The coal may be compacted before or after it is in the oven. While coal conveyors are suitable for charging ovens with particulate coal that is then partially compacted in the oven, such conveyors are generally not suitable for charging ovens with pre-compacted coal. Ideally, the coal should be compacted to greater than 800 kilograms per cubic meter in order to enhance the usefulness of lower quality coal. It is well known that as the percentage of lower quality coal in a coal blend is increased, higher levels of coal compaction are required up to about 1040 to 1120 kilograms per cubic meter. 
         [0009]    However, currently available processes are not suitable for providing a compacted coal charge that has a substantially uniform bulk density throughout the entire depth of an elongate coal charge bed at a relatively high rate of speed and without the generation of substantial amounts of coal dust during compaction. There is a need therefor, for an improved method and apparatus for compacting coal without generating coal dust and for charging coking ovens with pre-compacted coal. There is also a need for an apparatus for minimizing the amount of time required to provide a substantially uniform bed of compacted coal for use in making metallurgical coke. 
         [0010]    In accordance with the foregoing and other needs, the disclosure provides relatively high speed methods for increasing the bulk density of coal particles without impacting the coal particles and an apparatus for compacting coal for making metallurgical coke. The method includes depositing coal particles onto a charging plate external to a coking oven. The charging plate has side walls, and at least one movable end wall to provide an elongate bed of dry, uncompacted coal having an upper surface on the charging plate. The uncompacted coal is compacted by passing a vibratory cylindrical compactor along a length of the uncompacted coal for a number of passes sufficient to decrease a thickness of the bed of coal to less than about 80 percent of an original thickness of the uncompacted coal. The vibratory cylindrical compactor has a length to diameter ratio ranging from about 1.4:1 to about 2:1. In another aspect, an exemplary embodiment of the disclosure provides a coal compacting and coke oven charging apparatus. The apparatus has a coal bed transfer plate having side walls, at least one movable end wall, and a transfer plate translating mechanism for transporting compacted coal into the coke oven. A vacuum source is used for degassing the uncompacted bed of coal during the compaction process to provide a dry, compacted coal bed having a bulk density ranging from about 960 to about 1200 kilograms per cubic meter. 
         [0011]    In yet another aspect, an exemplary embodiment of the disclosure provides a coal compacting and coke oven charging apparatus The apparatus includes a coal bed charge car comprising a transfer plate having side walls, at least one movable end wall, and a transfer plate translating mechanism for transporting compacted coal into the coke oven. A coal compacting device is provided to compact the coal without impact energy. The coal compacting device includes a vibratory roller mechanism for compacting a bed of uncompacted coal on the transfer plate; a coal bed translation device attached to the vibratory roller mechanism for moving the vibratory roller mechanism along a length of the bed of uncompacted coal; an elevation mechanism on the coal bed translation device for lowering the vibratory roller to be in contact with the uncompacted coal during a compacting step and for raising the vibratory roller out of contact with compacted coal during an oven charging step; and a degassing device for degassing the uncompacted bed of coal during the compacting step. 
         [0012]    The method and apparatus described herein provide unique advantages for coking operations including providing coal with a relatively high bulk density in a relatively short period of time. Another advantage of the method and apparatus is that relatively simple mechanical devices may be used to compact the coal and transfer the compacted coal into the coke oven without using a pile-driver-type compaction device that may cause an increase in coal dust during compaction and that may cause damage to structures and equipment during the compaction process. A further advantage is that the resulting coal bed is substantially compacted throughout its depth to about the same uniform bulk density. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    Further advantages of the disclosed embodiments may be apparent by reference to the detailed description of exemplary embodiments when considered in conjunction with the drawings, which are not to scale, wherein like reference characters designate like or similar elements throughout the several drawings as follows: 
           [0014]      FIG. 1  is a plan view, not to scale, of a charging car, a coal filling station, and a compaction apparatus for a coke oven battery according an embodiment of the disclosure; 
           [0015]      FIG. 2  is a front elevational side view, not to scale, of the coal filling station, compaction apparatus, and charge car device according to an embodiment of the disclosure; 
           [0016]      FIG. 3  is side elevational end view, not to scale, of the charge car device and coal filling station according to an embodiment of the disclosure; 
           [0017]      FIG. 4  is an schematic side view, not to scale, of the charge car device according to an embodiment of the disclosure; 
           [0018]      FIG. 5  is an end elevational view, not to scale, of a charge car device according to an embodiment of the disclosure; 
           [0019]      FIG. 6  is an elevational view, not to scale, of the charge car device and side wall locking mechanism according to an embodiment of the disclosure; 
           [0020]      FIG. 7  is an elevational view, not to scale, of a portion of the charge car device and movable end wall for charging a coke oven according to an embodiment of the disclosure; 
           [0021]      FIG. 8  is a perspective view, not to scale, an adjustable end wall for a charge car device according to the disclosure; 
           [0022]      FIGS. 9A-9B  are schematic views, not to scale, of a method for compacting coal using a vibratory roller according to an embodiment of the disclosure; 
           [0023]      FIG. 10  is a side elevational view, not to scale, of the compaction station and charge car according to the disclosure; 
           [0024]      FIGS. 11A-11D  are perspective and side views, not to scale, of a compaction device containing the vibratory roller according to the disclosure; 
           [0025]      FIG. 12  is plan view, not to scale, of the coal compaction device and charge car according to the disclosure; and 
           [0026]      FIG. 13  is a graphical representation of bulk density versus compaction energy for a vibratory roller compaction test according to the disclosure. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0027]    As used herein the term “pile-driver-type device” is used to describe the use of a relatively high energy impact per unit of time in a reciprocating manner to compact the coal. Coal dust is generated during the compaction process with the pile-driver-type device due to relatively high impact energy and relatively high speed of the compaction mechanism as air is forced out of the coal. The term “vibratory roller mechanism” means a rolling mechanism that vibrates without imparting impact energy from a pile-driver-type device to the coal as described above. Accordingly, since the energy per unit time of the vibratory roller mechanism is substantially lower than the energy per unit time of the pile-driver-type devices. 
         [0028]    As described in more detail below, a high speed system  10  for compacting and charging coal to coke ovens  12  is illustrated in a plan view in  FIG. 1 . The system includes a movable coal charge car device  14 , a coal filling apparatus  16  for filling the coal charge car, and coal compaction apparatus  18  for compacting the coal in the coal charge car device  14 . The system  10  is particularly suitable for providing a compacted bed of coal having a depth of from about 75 to about 125 centimeters, a length ranging from about 10 to about 15 meters and a width ranging from about 2 to about 5 meters for charging a horizontal non-recovery coking oven  12 . 
         [0029]    With reference to  FIGS. 1-3 , a typical horizontal non-recovery coke oven battery contains a plurality of side by side coke ovens  12 . Each of the coke ovens  12  has a coal charge end  20  and a coke outlet end  22  opposite the charge end  20 . A coal coking cycle may range from 24 to 48 hours or more depending on the size of the coal charge to the coke oven  12 . At the end of the coking cycle, the coke is pushed out of the oven  12  into a hot car on the coke outlet end  22  of the oven using a discharge ram positioned adjacent the charge end  20  of the oven  12 . The discharge ram may be included on the charge car device  14  which may also include a device for removing a charge end oven door prior to pushing the coke out of the oven  12 . 
         [0030]    As shown in  FIG. 1 , the charge car device  14  is movable on rails  24  adjacent to an oven  12  to be charged and to a filling station  26  for filling the charge car device  14  with a predetermined amount of coal. The coal filling apparatus  16 , described in more detail below, includes a coal bin that is movable on elevated rails  30  orthogonal to rails  24  for movement along a length of the charge car device  14  for filling the coal filling apparatus  16  with a predetermined amount of coal by means of a conveyor  32  ( FIG. 3 ). Compacted coal  34  on the charge car  14  after leaving the filling station is also shown in  FIG. 3 . 
         [0031]    With reference now to  FIGS. 4-6 , various aspects of the components of the system  10  are illustrated and described in more detail. As shown in  FIG. 4 , the charge car device  14  includes a main support frame  36 , a translatable coal transfer plate or spatula  38 , a transfer plate support frame  40 , and a height adjustment mechanism  42  attached to the frame  40  for positioning a height of the transfer plate  38  relative to an oven floor for an oven  12  being charged with coal. The height adjustment mechanism  42  may also be used to lower the transfer plate  40  onto stationary piers, described in more detail below, for absorbing vibrations during a coal compaction step. 
         [0032]    The height adjustment mechanism  42  includes one or more actuators  44  for raising and lowering bearing rails  46  containing bearing rolls  48  or slide plates for translatable movement of the transfer plate  38 . The actuator  44  may be selected from a wide variety of mechanisms such as worm gears, chain drives, hydraulic cylinders, and the like. A hydraulic cylinder actuator  44  is particularly suitable for use in the height adjustment mechanism  42  described herein. 
         [0033]    Details of portions of the height adjustment mechanism  42  for raising and lowering the transfer plate  38  are provided in  FIG. 5 .  FIG. 5  is an end view of the charge car device  14  showing the height adjustment mechanism  42  attached to the frame  36 . The actuator  44  is attached to the frame  36  and to a first pivot arm  50  holding wheel  52 . The first pivot arm  50  is mechanically linked, as by a rod or other rigid linking device  54 , to a distal pivot arm  56  and wheel  57  that moves in conjunction with the first pivot arm  50  by action of the linking device  54 . Each of the first pivot arm  50  and distal pivot arm  56  is pivotally attached to the frame  36 . 
         [0034]    Upon activation of the actuator  44 , the pivot arms  50  and  56  are raised or lowered thereby raising or lowering the rails  46  supporting the transfer plate  38 . The wheels  52  enable movement of the rails  46  and transfer plate  38  toward or away from the oven  12  as needed to properly position the charge car device  14  relative to an oven  12  to be charged. 
         [0035]    Due to oven height disparities relative to a reference height of the rails  24 , the height adjustment mechanism  42  may be used to provide the transfer plate  38  at a desired elevation for translatable movement into the oven  12  to be charged with coal. Variations in oven height typically range from about one to about five inches. Accordingly, the height adjustment mechanism  42  should be capable of moving and holding the transfer plate  38  at an elevation that may vary over a range of from 2.5 centimeters to 15 centimeters from a reference elevation of the transfer plate  38 . It will be appreciated that height elevations ranges that may be needed for a particular oven battery may range more than from about 2.5 to about 15 centimeters. In addition to height adjustment of the transfer plate  38 , the transfer plate  38 , bearing rails  46 , and bearing rolls  48  may be telescoped toward the oven  12  for oven charging and away from the oven for movement of the charge car device along rails  24  while clearing other oven structures. A separate actuator may be used to move the rails  46  and transfer plate  38  toward and away from the oven  12 . 
         [0036]    The frame  36  of the charge car device  14  includes wheels  58  for a positioning the charge car device  14  along rails  24  to adjacent the coal charge end  20  of the oven  12  to be charged with compacted coal. The wheels  58  also enable the charge car device  14  to be positioned in the coal charging station  26  as described in more detail below. 
         [0037]    Tiltable side walls  60  are provided along a length of the transfer plate  38 . The tiltable side walls  60  may be rotated away from compacted coal on the transfer plate  38  when the transfer plate  38  and compacted coal thereon are being moved into the oven  12 . Rotating the tiltable side wall  60  away from the compacted coal may provide reduced friction between the side walls  60  and the compacted coal. 
         [0038]    As shown in  FIG. 6 , the tiltable side walls  60  are pivotally adjacent a first end  62  thereof to wall support members  64  and may be released from contact with the compacted coal or locked against movement as shown and described. Locking mechanisms  66 A and  66 B may be used in conjunction with the tiltable side walls  60  to prevent the tiltable side walls  60  from moving during a coal compaction process. Each locking mechanism  66 A and  66 B includes a pivot arm  68  having a roller  70  adjacent a first end  72  thereof and an actuator mechanism  74  adjacent a second end  76  thereof. Locking mechanism  66 A is shown in a first unlocked position and locking mechanism  66 B is shown in a second locked position in  FIG. 6 . 
         [0039]    At least one end  77  ( FIG. 7 ) of the charge car device  14  includes a movable end wall  78  and a ram head  80  attached to opposite sides of a back stop device  82  as shown in more detail in  FIG. 7 . The back stop device  82  containing the movable end wall  78  and ram head  80  may be rotated in a downward position for loading coal and compacting coal on the transfer plate  38 . When the back stop device  82  is rotated in the upward position as shown in  FIG. 7 , the transfer plate  38  and compacted coal  34  thereon may be translated into the oven  12  to charge the oven. 
         [0040]    During the oven charging step, the back stop device  82  ( FIG. 7 ) containing a ram head  80  may be rotated upward, as by actuator  84  so that the compacted coal  34  may be moved into the oven  12 . Once the oven  12  is charged with compacted coal  34 , the backstop device  82  may be rotated downward, as by actuator  84 , and may be moved toward the oven, as by trolley mechanism  86  to place the ram head  80  inside the oven  12  adjacent the compacted coal  34  to hold the compacted coal  34  in the oven  12  while the transfer plate  38  is being withdrawn from the oven  12 . After the transfer plate  38  has been withdrawn from the oven  12 , the backstop device  82  is rotated upward and is then moved using the trolley mechanism  86  to the position shown in  FIG. 7 . 
         [0041]    An opposing end of the transfer plate  38  includes an end wall  88  that may be stationary or vertically movable. In one embodiment, the end wall  88  may be adjusted up or down to clear a telescoping chute  104  on the coal filling apparatus  16 . Details of the adjustable end wall  88  are illustrated in  FIG. 8 . The adjustable end wall  88  has a stationary section  90  attached to the frame  36  and a movable section  92  that may be raised and lowered by an actuator mechanism  94 . 
         [0042]    The transfer plate  38  may be translated into and out of the oven  12  using a combination of a heavy duty, high speed chain and sprocket system  96  with a chain connected to a distal end  98  of the transfer plate  38  for movement of the transfer plate  38  along bearing rolls  48  attached to bearing rails  46  ( FIG. 4 ). During a coal charging operation, the chain and sprocket system  96  moves a portion of the transfer plate  38  into the oven  12  so that the compacted coal  34  may be deposited on a floor surface of the oven when the transfer plate  38  is retracted from the oven  12 . The transfer plate  38  has a thickness typically ranging from about 3.5 centimeters to about 8 centimeters and is preferably made of cast steel. 
         [0043]    As with the compacted coal charging device described in U.S. Pat. No. 6,290,494 to Barkdoll and U.S. Pat. No. 7,497,930 to Barkdoll et al., the disclosures of which are incorporated herein by reference, the charge car device  14  described herein may optionally include an uncompacted coal chamber for providing an insulating layer of uncompacted coal between the transfer plate  38  and the oven floor as the transfer plate  38  moves into the oven  12 . The uncompacted coal layer may insulate the transfer plate  38  from the radiant heat of the oven floor and may provide a relatively smooth, level surface for movement of the transfer plate  38  into and out of oven  12 . The weight of the compacted coal  34  and transfer plate  38  is sufficient to compress the uncompacted coal to increase its density above that of uncompacted coal. 
         [0044]    With reference again to  FIGS. 2-3 , the coal filling apparatus  16  for filling the charge car device  14  is illustrated and discussed in more detail. The coal filling apparatus  16  includes an elevated rail structure  100  for rails  30  and a weigh bin  102 ( a ) that is movable in a direction substantially orthogonal to rails  24  for filling the charge car device  14  substantially evenly with a predetermined amount of coal. The rails  30  also enable the weigh bin  102 ( b ) to be positioned adjacent a coal storage bin for refilling the weigh bin  102 ( b ) with the predetermined amount of coal. The cross conveyor  32  provides flow of coal from the storage bin to the weigh bin  102 . The weigh bin  102  is large enough to hold about 50 to 60 metric tons of coal particles. 
         [0045]    A telescoping chute and leveling device  104  is provided on a discharge end of the weigh bin  102  to substantially evenly fill the charge car device  14  with uncompacted coal. As the weigh bin  102 ( a ) traverses from one end of the charge car device  14  to the other end of the charge car device  14  along rails  30 , coal is metered into the charge car device  14  and smoothed to provide a substantially planar surface for the compaction process. The telescoping chute has a profile that provides a “batwing profile” of coal across a width of the transfer plate  38 . By “batwing profile” is meant that a depth of uncompacted coal adjacent the side walls  60  is greater than a depth of coal across a substantial portion of the width of the transfer plate  38 . 
         [0046]    Coal suitable for forming metallurgical coke is typically ground so that at least about 80% has an average size of less than about 3 millimeters as determined by standard screen analysis procedures. The uncompacted coal also has a moisture value ranging from about 6 to about 10 percent by weight and a bulk density ranging from about 640 to about 800 kilograms per cubic meter. As deposited on the transfer plate  38 , the uncompacted coal it typically about 50 to 60 percent by volume coal particles and about 40 to about 50 percent by volume voids. 
         [0047]    After filling the charge car device  14  with the predetermine amount of coal, typically about 45 to about 55 metric tons of coal, the weigh bin  102 ( a ) is moved to position  102 ( b ) ( FIG. 2 ) in order to conduct a compacting step for compacting the coal. The compaction device  18  used for compacting the coal includes the compaction apparatus  110  for rapidly compacting the coal in the charge car  14  as illustrated schematically in  FIGS. 9A-9B . The compaction device  18  includes a vibratory roller  112  that rolls across uncompacted coal  114  to provide compacted coal  34  so the depth of coal is changed from an initial depth D 1  to a compacted depth (D 2 ). 
         [0048]    The compaction apparatus  110  is movable on a support system  116  that includes fixed rails  118  and movable rails  120  ( FIGS. 2 and 10 ). Once the charge car  14  is loaded with coal, the movable rails  120  are lowered in a drawbridge-like manner to be adjacent both sides of the charge car  14  so that the compaction apparatus  110  can traverse a length of the charge car  14  on the telescoping rails  120  as illustrated in  FIGS. 10 and 12 . 
         [0049]    As shown in  FIGS. 11A-11D , the compaction apparatus  110  includes a support frame  122  that is movable on the fixed rails  118  and telescoping rails  120 . The support frame  122  also includes a roller frame  124  that may be raised as shown in  FIGS. 11A and 11C  or lowered as shown in  FIGS. 11B and 11D  by means of actuator devices  126 . When the compaction apparatus  110  is in the raised position, the compaction apparatus  110  may be moved over the uncompacted coal  114  in the charge car  14 . During the compaction process, the compaction apparatus  110  is in the lowered position for vibratory rolling over the uncompacted coal  114  to compact the coal. 
         [0050]    A plan view of the compaction apparatus  110  relative to the charge car  14  is illustrated in  FIG. 12 . The uncompacted coal is disposed in the charge car  14  and the compaction apparatus  110  traverses a length of the charge car  14  during the compaction process. The coal may be compacted in from about 2 to about 6 passes of the compaction apparatus  110 . In one embodiment, the compaction apparatus  110  may make a first pass in a direction of arrow  128 , with or without vibration while the vibratory roller  112  is in contact with the uncompacted coal  114 . The compaction apparatus  110  then makes a second pass in the direction of arrow  130  desirably while the vibratory roller  112  is vibrating to compact the coal. Typically about four total passes are required to compact the coal to the desired bulk density for use in the coke ovens  12  wherein a first pass is conducted without vibration and the subsequent three passes are conducted with vibration. 
         [0051]    As shown in  FIG. 9A , a length L of the vibratory roller  112  may range from about 90 to about 99 percent of a width W of a bed of uncompacted coal  114  to be compacted and a length to diameter ratio ranging from about 1.4:1 to about 2:1. The vibratory roller  112  may have a total weight of from about 25 to about 60 metric tons and traverses the uncompacted coal at a speed ranging from about 0.5 to about 3.0 kilometers per hour during the compaction process. The vibratory roller  112  has a vibrating frequency ranging from about 10 to about 50 Hz with an amplitude ranging from about 1 to about 5 mm and a centrifugal force ranging from about 3000 to about 3600 Newton-meters. 
         [0052]    During the compaction process, air from the uncompacted coal  114  may be vented through vents  136  in the side walls  60  of the charge car ( FIG. 4 ). Venting of air or degassing the coal enables faster compaction of the coal  114 . The vents  136  may be 30 cm 2  wire mesh or perforated screen vents that are spaced apart from one another about 60 centimeters, center to center, along the side walls  60  of the charge car  14 . The vents  136  have openings between adjacent wires of from about 75 to about 230 microns in order to minimize the amount of coal entrained in the air vented during the compacting process. 
         [0053]    The vents  136  may be vented to the atmosphere, or may be connected in gas flow communication with a vacuum pump and dust collection system  108  ( FIG. 2 ) as described in more detail in U.S. Pat. No. 7,497,930 to Barkdoll et al., the disclosure of which is incorporated herein by reference. During the compaction process, the vacuum pump may apply a vacuum ranging from about 185 to about 280 mm Hg on the probes to remove entrained air from the uncompacted coal bed during the compaction process. Volumetric flow rate of gas during the compaction process for may range from about 50 cubic meters per minute to about 85 cubic meters per minute. 
         [0054]    Unlike the use of impact energy to compact the coal, the vibratory roller  112  does not generate a significant amount of dust during the compaction process since the vibratory energy per unit time used is significantly less than an impact energy per unit time required to achieve similar coal bulk densities using the pile-driver-type device. For example, an impact pile driver as described in U.S. Pat. No. 7,497,930 may apply an energy of about 221,208 kilogram-force meter/sec to the coal to provide a bulk density ranging from about 1040 to 1120 kilograms per cubic meter. The same bulk density may be achieved with the vibratory roller  112 , according to embodiments of the disclosure with an energy of from about 2 to about 5 kilograms-force meter/sec. Accordingly, a dust collection system is not necessarily required with the vibratory roller  112  while it is desirable to use a dust collection system with a compaction system that uses impact energy to compact the coal. However, using a vacuum pump during the compaction process may be desirable in order to reduce a moisture content of the coal whereby less energy may be required for coking the coal. 
         [0055]    In order to reduce shock waves from being transmitted though the wheels  58  and rails  24 , support piers  134  ( FIG. 4 ) may be provided to support the charge car  14  in the filling station  26  during the compaction process. Accordingly, the height adjustment mechanism  42  may be actuated to lower the charge car  14  from about 2 to about 6 centimeters so that the transfer plate support frame  40  ( FIG. 4 ) of the charge car  14  is supported mainly by the piers  134  rather than the wheels  58  and frame  36 . 
         [0056]    The compaction apparatus  18  described above may be sufficient to compact a bed of coal having an initial depth ranging from about 135 to about 145 centimeters to a bulk density of greater than about 800 kilograms per cubic meter in less than about six minutes, and typically in less than about four minutes. The compaction apparatus  18  described herein may provide substantially uniformly compacted coal through the depth of the coal bed. Prior art compaction processes typically provide non-uniform compaction of coal through the depth of the coal bed. 
         [0057]    Typical cycle times for filling the charge car  14  with about 52 metric tons of coal and compacting the coal to a target bulk density of about 1040 kilograms per cubic meter are provided in the following table. 
         [0000]    
       
         
               
               
               
             
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                 Time 
               
               
                 Step No. 
                 Step Description 
                 (seconds) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 1 
                 Telescoping Coal Fill Chute Lowered Into Car 
                 10 
               
               
                 2 
                 Charge Car Filled With Coal (14 meters long) 
                 45 
               
               
                 3 
                 Retract Telescoping Coal Fill Chute 
                 10 
               
               
                 4 
                 Move Compaction Apparatus Over Charge Car 
                 25 
               
               
                 5 
                 Lower Vibratory Roller Onto Coal Bed 
                 15 
               
               
                 6 
                 Move Vibratory Roller Over Coal Bed 
                 190 
               
               
                 7 
                 Retract Vibratory Roller From Coal Bed 
                 15 
               
               
                   
                 Total Time 
                 310 
               
               
                   
               
             
          
         
       
     
         [0058]    It will be appreciated that the entire process of filling and compacting coal using the vibratory roller and degassing system described above may be achieved in less than about six minutes for the amount of uncompacted coal and the targeted bulk density provided in this example. 
         [0059]    In the following example a compaction test on twenty-eight metric tons of coal was conducted to determine the resulting depth and bulk density of the compacted coal after impacting the uncompacted coal bed multiple times while venting air from the coal bed using wall vents as described above to degas the coal during the compaction process. The uncompacted coal bed was placed between concrete barriers on a road bed. Multiple passes of a vibratory roller applying 2200 kilogram-force meter per metric ton of coal was used. The results are shown in the following table and in  FIG. 13 . 
         [0000]    
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                   
                 Coal Depth 
                 Bulk Density 
               
               
                   
                 Activity 
                 (cm) 
                 (kg/m 3 ) 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Coal between concrete barriers 
                 123 
                 825 
               
               
                   
                 After first roller pass 
                 102 
                 995 
               
               
                   
                 After second roller pass 
                 99 
                 1021 
               
               
                   
                 After third and fourth roller pass 
                 94 
                 1076 
               
               
                   
                 After fifth and sixth roller pass 
                 94 
                 1076 
               
               
                   
                   
               
             
          
         
       
     
         [0060]    In the foregoing description, the entire apparatus with the exception of conveyor belts, electrical components and the like may be made of cast or forged steel. Accordingly, robust construction of the apparatus is possible and provides a relatively long lasting apparatus which is suitable for the coke oven environment. 
         [0061]    The apparatus and methods described above enable use of less costly coal for metallurgical coke production thereby reducing the overall cost of the coke. Depending on the particular coal source and the level of compaction achieved, a compacted coal charge made according to the invention may include from about 30 to about 60 wt. % non-coking coal. The amount of coke produced by the apparatus of the invention may also be increased from 30 to 40 metric tons up to about 45 to about 55 metric tons as a result of the compaction process. More consistent coal charge physical parameters such as coal charge height, width and depth are also a benefit of the apparatus and methods according to the invention. 
         [0062]    It is contemplated, and will be apparent to those skilled in the art from the preceding description and the accompanying drawings that modifications and/or changes may be made in the embodiments of the disclosure. Accordingly, it is expressly intended that the foregoing description and the accompanying drawings are illustrative of exemplary embodiments only, not limiting thereto, and that the true spirit and scope of the present disclosure be determined by reference to the appended claims.