Patent Publication Number: US-2022236008-A1

Title: In-feed hopper and meter for carbon-based feedstock processing system

Description:
BACKGROUND OF THE INVENTION 
     Related Applications 
     The present application is a divisional application of and claims priority to and the benefit of U.S. application Ser. No. 16/210,825, filed Dec. 5, 2018, which itself is a divisional application of and claims priority to and the benefit of U.S. Non-Provisional patent application Ser. No. 14/602,651, filed Jan. 22, 2015 and issued as U.S. Pat. No. 10,180,284 on Jan. 15, 2019, the entire disclosures of which are incorporated herein by reference in their entirety. 
     Field of the Invention 
     The present invention relates to processing carbon-based feedstock, and in particular to an in-feed hopper and meter for feeding feedstock into a distillation chamber. 
     Description of the Related Art 
     Coal is an abundant natural resource capable of exploitation to produce large amounts of energy. Coal in its raw form, however, usually contains undesirable compositions in the form of a number of other chemical compositions or elements. One problem faced in the coal industry is that traditional means of extracting energy from coal have been the subject of concerns, due to possible adverse environmental consequences because of the undesirable compositions usually present in raw coal. For example, historically coal has been burned to create heat, such as to turn water into steam to power a turbine and generate electricity. This process generates large amounts of gaseous emissions containing small amounts of the undesirable compositions which harm the environment. As a result, the use of coal as an energy source can cause tension between the need for an economic way to produce energy on the one hand, and environmental concerns on the other. 
     During a typical coal processing operation, coal and other carbon-based products are often subjected to distillation processes in order to extract various products therefrom. Typically, the coal or other carbon-based feedstock is fed directly into a distillation chamber from open, atmospheric hoppers. The feedstock can pass through a meter as it enters the distillation chamber so that the volume of the feedstock entering the distillation chamber is known. 
     The use of open air hoppers can be problematic because the outside atmosphere contains oxygen. Accordingly, feedstock introduced to a distillation chamber from an open air hopper is often mixed with air containing oxygen. Many distillation processes, however, inhibit oxidation, or the burning of the feedstock during the distillation process, so that the presence of such oxygen in the distillation chamber is problematic. 
     In addition, much of the raw feedstock supplied to an in-feed hopper is first passed through a grinder, in order to reduce the size of individual units of feedstock so that the feedstock can pass through the hopper and meter more effectively. In some cases, however, pieces of feedstock are introduced to the hopper and meter that were not sufficiently crushed by the grinder, and that are large so that they cannot fit through the meter. Such large pieces of feedstock can become wedged in the meter, binding the meter so that it cannot continue processing the feedstock, and, in some instances, damaging the meter. 
     SUMMARY OF THE INVENTION 
     Briefly, the present invention provides a meter for controlling the flow of feedstock from an in-feed hopper to a distillation unit. The meter includes a cylindrical roller having a first end, a second end, and an outer diameter, the roller defining a recess that extends helically substantially from the first end to the second end. The meter also includes a sleeve circumscribing a portion of the outer diameter of the cylindrical roller. The sleeve has an open first side that allows the passage of feedstock into the recess of the roller, and an open second side that allows the passage of feedstock out of the recess of the roller as the roller rotates relative to the sleeve. In addition, the meter includes a housing fixedly attached to the sleeve and capable of attachment to the in-feed hopper and the distillation unit such that feedstock must pass through the housing to get from the in-feed hopper to the distillation unit. 
     In some embodiments, the meter can further include a wear plate having substantially the same length as the roller, and attached to the housing so that an edge of the wear plate is proximate an outer diameter of the roller to shear feedstock extending out of the recess as the roller turns. In addition, the second open side of the sleeve can have a helical opening corresponding in shape and size to the recess of the roller, so that when the recess of the roller aligns with the helical opening, the feedstock passes through the helical opening all at once into the distillation unit. 
     Furthermore, in certain embodiment of the invention, the distance between the outer diameter of the roller and the sleeve can be about  1 / 8  of an inch or less to help prevent the flow of gases from the distillation unit to the in-feed hopper. In addition, the recess in the roller can have a bottom and two sides, wherein the transverse cross-section of the recess is substantially U-shaped. Alternatively, the recess in the roller can have a bottom and two opposing sides, wherein the sides of the recess slope outwardly away from one another from the bottom of the recess to the outside diameter of the roller. 
     Another embodiment of the invention provides an in-feed hopper and metering system for introducing feedstock into a distillation unit. The system includes a first hollow chamber having a sealable inlet for receiving feedstock, a second hollow chamber attached to the first hollow chamber and having an outlet for discharging feedstock, and a sealing gate between the first hollow chamber and the second hollow chamber having an open and a closed position. The sealing gate separates the first hollow chamber from the second hollow chamber when in the closed position during filling and pressurization of the first hollow chamber. Alternately, the sealing gate joins the first hollow chamber and the second hollow chamber when in the open position, to allow passage of the feedstock from the first hollow chamber to the second hollow chamber. The system further includes a meter having a roller partially circumscribed by a sleeve, the roller having a helical recess that accepts feedstock from the second hollow chamber, and then discharges the feedstock to a distillation unit. 
     In certain example embodiments, the roller can have a first end, a second end, and an outer diameter, and the helical recess can extend substantially from the first end to the second end. In addition, the sleeve can have an open first side that allows the passage of feedstock into the recess of the roller, and an open second side that allows the passage of feedstock out of the recess of the roller as the roller rotates relative to the sleeve. 
     In some embodiments, the meter can also include a housing fixedly attached to the sleeve and capable of attachment to the in-feed hopper and the distillation unit, such that feedstock must pass through the housing to get from the in-feed hopper to the distillation unit. In addition, the meter can include a wear plate having substantially the same length as the roller, and attached to the housing so that an edge of the wear plate is proximate an outer diameter of the roller to shear feedstock extending out of the recess as the roller turns. Furthermore, the second open side of the sleeve can include a helical opening corresponding in shape and size to the recess of the roller so that when the recess of the roller aligns with the helical opening, the feedstock passes through the helical opening all at once into the distillation unit. 
     Yet other embodiments of the system may include a meter wherein the distance between the outer diameter of the roller and the sleeve is about ⅛ of an inch or less to help prevent the flow of gases from the distillation unit to the in-feed hopper. The recess in the roller can have a bottom and two sides, wherein the transverse cross-section of the recess is substantially U-shaped. Alternatively, the recess in the roller can have a bottom and two opposing sides, wherein the sides of the recess slope outwardly away from one another from the bottom of the recess to the outside diameter of the roller. 
     Another embodiment of the invention provides a method of providing feedstock to a distillation unit. The method includes the steps of filling a first hollow chamber with feedstock through an inlet in the first hollow chamber, sealing the inlet of the first hollow chamber, pressurizing the first hollow chamber until the pressure within the first hollow chamber is about equal to the pressure inside a second hollow chamber, and opening a passage between the first hollow chamber and the second hollow chamber so that the feedstock can pass from the first hollow chamber to the second hollow chamber. In addition, the method includes the step of discharging the feedstock from the second hollow chamber into a feed meter having a roller with a recess, the roller designed to accept feedstock into the recess, rotate the feedstock away from the second hollow chamber, and discharge the feedstock to a distillation unit. 
     Some embodiments of the method can include the steps of purging oxygen from the first hollow chamber, and replacing the oxygen in the first hollow chamber with nitrogen. In addition, the method can include shearing fragments of the feedstock with a wear plate located adjacent the roller in the meter to a size that fits within the recess of the roller, and discharging the feedstock from the meter into the distillation unit evenly to prevent the feedstock from massing inside the distillation unit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is perspective view of an in-feed hopper and meter according to an embodiment of the present invention; 
         FIG. 2  is a perspective view of an upper portion of the infeed hopper of  FIG. 1 ; 
         FIG. 3  is a perspective view of a lower portion of the infeed hopper of  FIG. 1 ; 
         FIG. 4A  is a side cross-sectional view of a meter assembly according to an embodiment of the present invention, taken along line  4 A- 4 A of  FIG. 1 ; and 
         FIG. 4B  is an end partial cross-sectional view of the meter assembly of claim  4 A, taken along line  4 B- 4 B of  FIG. 1 ; 
         FIG. 5A  is a top view of a meter housing according to an embodiment of the present invention; 
         FIG. 5B  is a side view of the meter housing of  FIG. 5A ; 
         FIG. 6A  is a top view of a roller housing according to an embodiment of the present invention; 
         FIG. 6B  is a side view of the roller housing of  FIG. 6A ; 
         FIG. 7A  is a side view of a roller according to an embodiment of the present invention; 
         FIG. 7B  is an end view of the roller of  FIG. 7A ; 
         FIG. 8A  is a side view of a wear plate according to an embodiment of the present invention; and 
         FIG. 8B  is an end view of the wear plate of  FIG. 8A . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In  FIG. 1 , there is depicted a perspective view of an infeed hopper  10  attached to a feed meter  12 . The feed meter  12  is designed to be attached at a lower end  14  to a distillation chamber (not shown) where feedstock from the infeed hopper  10  will be processed. The infeed hopper  10  includes an upper hopper portionl 6  and a lower hopper portion  18 . The upper hopper portion  16  is separated from the lower hopper portion  18  by a sealing gate  20 . The sealing gate  20  is capable of adjustment between an open position and a closed position. When in the open position, an opening between the upper hopper portion  16  and the lower hopper portion  18  is created, so that feedstock can pass from the upper hopper portion  16  into the lower hopper portion  18 . Alternately, when the sealing gate  20  is in the closed position, the upper hopper portion  16  is separated from the lower hopper portion  18 . 
     Referring to  FIG. 2 , there is shown an upper hopper portion  16 , including an upper hopper inlet  22  and an upper access port  24 . The inlet  22  is used to receive feedstock into the upper hopper portion  16 , and, although shown to be round, could be any suitable shape and diameter. The upper access port  24  includes a cover  26  that can be removed to gain access to the inside of the upper hopper portion  16  as needed, such as, for example, to clear jammed feedstock out of, or otherwise service, the upper hopper portion  16 . 
       FIG. 3  shows a lower hopper portion  18 , including an inlet  28  which, when the upper and lower hopper portions  16 ,  18  are combined, is associated with the sealing gate  20 . The inlet  28  is used to receive feedstock into the lower hopper portion  18  from the upper hopper portion  16  when the gate  20  is in the open position. The lower hopper portion  18  further includes a lower access port  30  with a cover  32  that can be removed to gain access to the inside of the lower hopper portion  18  as needed, such as, for example, to clear jammed feedstock out of, or otherwise service, the lower hopper portion  18 . The lower end  34  of the lower hopper portion  18  is configured for attachment to the meter  12 , so that feedstock passes from the lower hopper portion  18  into the meter  12 . In some embodiments, such as that shown in  FIGS. 1 and 3 , the lower end  34  of the lower hopper portion  18  may include a flange  36  that corresponds to a flange  38  of the meter  12 . The flange  36  of the lower hopper portion  18  and the flange  38  of the meter  12  can be attached so that the lower end  34  of the lower hopper portion  18  aligns with the meter  12 . 
     According to one possible process of the invention, feedstock can be introduced to a distillation chamber through the infeed hopper  10  and the meter  12 . In such a process, feedstock, which may be coal, biomass, or some other carbon-based feedstock, is introduced into the upper hopper portion  16  thought the inlet  22  while the sealing gate  20  is closed. Thus, the upper hopper portion  16  can be filled without the feedstock passing into the lower hopper portion  18 . Once a predetermined amount of feedstock has been inserted into the upper hopper portion  16 , the inlet  22  of the upper hopper portion  16  can be closed and sealed. 
     Next, air may be purged from the upper hopper section  16 . This may be accomplished, for example, by injecting nitrogen into the upper hopper section  16  and purging the air, such as through a vent. Purging the air from the upper hopper section  16  provides certain benefits to the system. For example, by purging the air, including oxygen in the air, from the upper hopper portion  16 , such oxygen is prevented from progressing further into the system. This is desirable because if oxygen enters the distillation chamber downstream, oxidation could occur, leading to burning of the feedstock in the distillation chamber. This could ruin the feedstock, and also create a possible fire hazard. 
     Another step that may occur while the sealing gate  20  is closed and the feedstock is confined to the upper hopper portion  16 , is to pressurize the upper hopper  16  so that the pressure is substantially equivalent to that in the lower hopper portion  18 . Such pressurization of the lower hopper portion  18  occurs because the distillation chamber may be pressurized as part of the distillation process. Since the distillation chamber is open to the lower hopper chamber  18  via the meter  12 , which is not airtight, any elevation in pressure inside the distillation chamber may lead to a corresponding pressure increase inside the lower hopper portion  18 . If the sealing gate  20  were opened between the upper and lower hopper portions  16 ,  18  without first equalizing the pressures, such action could lead to a possible loss of pressure in the unit. 
     With the pressure in the upper hopper portion  16  adjusted to substantially match that of the lower hopper portion  18 , the sealing gate  20  may be opened, at which point the feedstock in the upper hopper portion  16  can be gravity fed into the lower hopper portion  18  via the inlet  28  of the lower hopper portion  18 . Thereafter, the sealing gate  20  may be closed, and the inlet to the upper hopper portion  22  may again be opened to receive more feedstock. Furthermore, from the lower hopper portion  18 , the feedstock may pass through the meter  12 , as described herein, and from there into the distillation chamber. 
     Referring now to  FIGS. 4A and 4B , there are shown side and end cross-sectional views of the meter  12  according to an embodiment of the present invention. The meter  12  is an assembly that consists of a meter housing  40 , a roller housing  42 , a roller  44 , and a wear plate  46 . The roller  44  may have a helical recess  48 , shown and described in more detail below. The roller housing may also have a helical opening  50  that corresponds to the helical recess  48  of the roller  44 . The meter includes flanges  38  configured to correspond to flanges  36  of the bottom end  34  of the lower hopper portion  18 , as shown in  FIG. 1 . Similarly, the meter  12  may have flanges  52  that correspond to flanges of a distillation chamber (not shown) at a bottom end of the meter  12 . In practice, all feedstock must pass through the meter  12  to get from the lower hopper portion  18  to the distillation unit. As described below, the novel features and design of the meter  12  help to ensure that the feedstock is fed into the distillation unit at an even rate, and that the individual pieces of the feedstock are of a small enough size to avoid jamming the meter or other equipment.  FIGS. 5A-8B  depict the individual components of the meter  12 , and fit together as shown in  FIGS. 4A and 4B . 
       FIGS. 5A and 5B  show the meter housing  40  according to an embodiment of the present invention. The housing is at least partially open on the top and bottom, as shown in  FIG. 5A . This allows feedstock to enter the meter  12  through the top, and then to exit the meter  12  through the bottom. The top and bottom may include transverse frame members  54  for support and to add strength to the meter housing  40 . In  FIG. 5A , the transverse frame members  54  are shown to be at the ends of the meter housing  40 , but such frame members  54  could be located anywhere along the length of the meter housing  40 . In addition, although only two frame supports  54  are shown, more frame supports  54  could be added to the meter housing  40 . The sides of the meter housing  40 , on the other hand, may be solid, to add rigidity and strength to the meter housing  40 . Alternatively, although not shown, the sides could be open in places, but have a rigid framework sufficient to provide the support necessary for the meter housing  40 . 
       FIGS. 6A and 6B  show the roller housing  42  of the meter  12 . The roller housing  42  has an open upper side  56  and an open lower side  58 . Again, this is to allow passage of feedstock from the upper side of the roller housing  42  and out of the lower side of the roller housing  42 . The roller housing  42  is rigidly fixed to the meter housing  40 , as shown, for example, in  FIG. 4B . As shown, in some embodiments, the roller housing  42  may be attached to the meter housing  40  with roller housing support members  60 . 
     The open upper side  56  and open lower side  58  of the roller housing  42  may be of any appropriate configuration. For example, as shown in  FIGS. 4B, 6A, and 6B , the open upper side  56  of the roller housing  42  may be broad, and have a width nearly as large as the diameter of the roller housing  42 . Such an open upper side  56  may be advantage to help increase the amount of feedstock that passes through the roller housing  42  on the upper side thereof. As shown in  FIGS. 6A and 6B , on the other hand, the open lower side  58  of the roller housing  42  may be smaller and have a helical shape. Such a helical shape may be configured to correspond to the helical recess  48  of the roller  44 , so that feedstock can be discharged from the open lower end  58  of the roller housing  42  evenly into a distillation chamber, as discussed hereinbelow. Of course, the open lower side  42  of the roller housing  42  can alternatively have any configuration, including a broad longitudinal cut similar to the open upper side  56 . 
       FIGS. 7A and 7B  show a roller  44 , according to one embodiment of the present invention. One unique feature of the roller  44  shown in these figures is the helical recess  48  in the roller  44 . As shown, the roller  44  includes a pin  62  aligned with the longitudinal axis of the roller  44 . The helical groove  48  extends across the length of the roller  44 , and curves across the length so that the cross-section of the recess  48  at the first end  64  is offset substantially  90  degrees from the cross-section of the recess  48  at the second end  66 . The helical recess  48  has a depth sufficient to receive feedstock and convey the feedstock from the top of the meter  12  to the bottom of the meter  12 . 
     In the assembly, as shown in  FIGS. 4A and 4B , the roller  44  is positioned within the roller housing  42 . The pin  62  of the roller  44  extends through the roller housing  42  and, in some embodiments, the meter housing  40 . In practice, the roller  44  is turned within the roller housing  42  by turning the pin  62 . In the example meter  12  depicted, the shaft turns on bearing assemblies  68  located at ends of the meter housing  40 . The types of bearings used, and their positioning relate to the components  12  is not critical, so long as they are configured to allow the rotation of the roller  44  relative to the roller housing  42  and the meter housing  40 . The tolerance between the roller  44  and the roller housing  42  is preferably small, such as about  1 / 8  of an inch or less, to prevent the passage of the materials, and minimize the passage of gas, between the roller  44  and the roller housing  42 . 
     In practice, the roller  44  acts to convey feedstock through the meter  12  according to the following method. First, the feedstock is gravity fed from the lower hopper portion  18  into the top of the meter  12 . Due to the open nature of the top of the meter housing  40 , and the open upper side  56  of the roller housing  42 , the feedstock is able to come into direct contact with the surface of the roller  44 . Because of the tight tolerances, however, between the roller  44  and the roller housing  42 , the feedstock is prevented from fitting between the roller  44  and the roller housing  42  except via the helical recess  48 . 
     As the roller  44  turns, the helical recess  48  becomes exposed to the feedstock via the open top side  56  of the roller housing  42 . Thus, the feedstock enters the helical recess  48 . Thereafter, as the roller  44  continues to turn, the helical recess  48 , now full of feedstock, rotates away from the open upper side  56  of the roller housing  42 , and the feedstock within the helical recess  48  is conveyed toward the open lower side  58  of the roller housing. Once the helical recess  48  aligns with the open lower side  58  of the roller housing  42 , the feedstock falls (via gravity) through the open lower side  58  and through a lower end of the meter housing  40  into the distillation chamber. Because the amount of feedstock that can be carried by the helical recess  48  is known, the amount of feedstock transmitted from the lower hopper portion  18  to the distillation unit can be calculated and controlled using the meter  12 . In addition, use of the helical open lower side  58  of the roller housing  42 , can help to ensure that all of the feedstock held in the helical recess  48 , along the entire length of the roller  44 , is dropped evenly and contemporaneously into the distillation chamber. 
       FIGS. 8A and 8B  shown a wear plate  46  used in the meter  12  to help control the size of individual pieces of feedstock that enter the distillation unit, and to cut down large pieces of feedstock that might otherwise jam the meter  12 . The wear plate is an elongate plate as shown in  FIG. 8A . The cross-section of the wear plate  46  includes a transverse base  70  that culminates in a sharpened edge  72 . The cross-section of the wear plate  46  also includes an angled stem  74 . 
     When positioned in the meter  12 , as shown in  FIG. 4B , the sharp edge  72  of the wear plate  46  is positioned adjacent the surface of the roller  44  and is rigidly attached to meter housing  40 , the roller housing  42 , and/or the roller housing support members  60 . The sharp edge  42  is also positioned so that the roller  44  turns toward the sharp edge  72  of the wear plate  46 . 
     In practice, as the roller turns, and particles of feedstock that are too large to fit into the helical recess  48  are pulled by the roller  44  into the sharp edge  72  of the wear plate  46 . The sharp edge  72  of the wear plate  46  shears those particles to a smaller size. Furthermore, the helical shape of the recess  48 , combined with the substantially straight edge  72  of the shear plate  46 , combine so that when the recess  48  rotates toward the sharp edge  72 , the confluence of the two features creates a wedge. As particles of feedstock become trapped in the wedge, they cannot easily be loosed, and are sheared by the sharp edge  72 , whereas in the absence of such a wedge, the particles may bind up the meter. 
     Thus, the helical recess  48  is beneficial because it provides a means to help large particles of feedstock to be sheared, thereby avoiding jamming of the meter. Furthermore, the smaller feedstock particle size that results helps to avoid jamming of equipment down line from the meter as well, such as coolers used to cool the feedstock after it exits the distillation chamber. 
     The invention has been sufficiently described so that a person with average knowledge in the matter may reproduce and obtain the results mentioned in the invention herein Nonetheless, any skilled person in the field of technique, subject of the invention herein, may carry out modifications not described in the request herein, to apply these modifications to a determined structure, or in the manufacturing process of the same, requires the claimed matter in the following claims; such structures shall be covered within the scope of the invention. 
     It should be noted and understood that there can be improvements and modifications made of the present invention described in detail above without departing from the spirit or scope of the invention as set forth in the accompanying claims.