Abstract:
A method of producing a fuel substance by separating materials in a recycling operation based on BTU component content is provided. A stream of materials including non-sorted, heterogeneous, recycled materials is shredded. The stream of materials is separated into heavy and light materials with a separator that discharges the light and heavy materials in respective light and heavy material streams. Ferrous and non-ferrous materials are magnetically separated from the heavy material stream. The non-ferrous materials are discharged to a screen for further separation. The light materials are processed through a rotary trommel and a non-ferrous metal separator to separate the light materials into fine, coarse, and non-ferrous metal materials, the coarse materials having a BTU component content of at least four thousand BTU&#39;s per ton. Low density materials are separated from the coarse materials with a low density separator, thereby increasing the BTU component content of the coarse materials.

Description:
BACKGROUND 
   The present invention relates to solid waste material sorting and recycling systems. More particularly, the present invention relates to a method of producing a reusable fuel substance as well as other useful substances by separating materials in a salvage operation which receives mixed materials, such as automobiles. 
   Since millions of automobiles become old or unusable, automobile disposal creates an enormous problem. The scrap metal industry has attempted to alleviate this problem by designing several types of mechanized recycling systems. 
   At these recycling centers, complete automobile bodies (including the seats and upholstery) as well as other types of metallic (containing various amounts of contamination and non-metallic components) are shredded into smaller pieces. The goal is to separate the metallic from the non-metallic components. While the metallic materials are typically recycled, the non-metallic materials have traditionally been taken to a dump for disposal. This has primarily been due to the industry&#39;s inability to find a viable, cost-effective alternative. 
   In an effort to extend the life of existing landfill facilities and, as space in these facilities becomes more limited, there is renewed interest in exploring new alternatives. This is heightened by the trend in automobile design toward fewer metallic components and an increase in the number of non-metallic components. Therefore, it is necessary to develop systems for sorting and recycling as many reusable automobile components as possible. Specifically, there remains a need for improved methods whereby non-metallic materials are converted into reusable byproducts such as, for example, a fuel substance with a relatively high BTU component content. 
   SUMMARY 
   The present invention provides a method of producing a fuel substance by separating materials in a recycling operation based on BTU component content is provided. A stream of materials including non-sorted, heterogeneous, recycled materials is shredded. The stream of materials is separated into heavy and light materials with a separator that discharges the light and heavy materials in respective light and heavy material streams. Ferrous and non-ferrous materials are magnetically separated from the heavy material stream. The non-ferrous materials are discharged to a screen for further separation. The light materials are processed through a rotary trommel and a non-ferrous metal separator to separate the light materials into fine, coarse, and non-ferrous metal materials, the coarse materials having a BTU component. Low density materials are separated from the coarse materials with a low density separator, thereby increasing the BTU component content of the coarse materials 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing summary, as well as the following detailed description, will be readily understood in conjunction with the appended drawings which illustrate the preferred embodiments of the invention in the drawings. 
       FIG. 1  is a prescriptive view of the separation and recycling system embodying the method of the present invention; and 
       FIG. 2  is a schematic flow diagram of the separation and recycling system embodying the method of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Certain terminology is used in the following description for convenience only and is not considered limiting. Words such as “front,” “back,” “top,” and “bottom” designate directions in the drawings to which reference is made. This terminology includes the words specifically noted above, derivatives thereof, and words of similar import. Additionally, the terms “a” and “one” are defined as including one or more of the referenced item unless specifically noted. The phrase “at least one of” followed by a list of two or more items, such as A, B, or C, means any individual one of A, B, or C, as well as any combination thereof. 
   The preferred embodiments of the present invention are described below with reference to the drawing figures where like numerals represent like elements throughout. 
   Referring to  FIGS. 1 and 2 , a separation and recycling system used in accordance with the present invention is shown. In the preferred method of the present invention, a scrap feeder  5  delivers a non-sorted (heterogeneous) material stream of recycled material, such as automobiles, office furniture, appliances, industrial equipment, etc. (all of which may contain plastic and/or fabric) to a shredder  10  where they are shredded or fragmented. The shredder  10  is preferably a rotary hammer mill. However, it will be recognized by those skilled in the art that other types or configurations of shredding equipment may be utilized, if desired. Preferably, a surfactant is added to the material stream during shredding. 
   The shredded materials  7  are then carried by a conveyor  8  to a gravity separator  11 . The gravity separator  11  preferably includes an intake tube  15 , a cyclone air separator  18  and a clean air exhaust tube  19 . The intake tube  15  has a first end that is connected to the intake side of the cyclone air separator  18  and a second end connected to a collection housing  14  where the shredded materials  7  are transported by the conveyor  8 . The vacuum air flow generated by the cyclone separator  18  is directed to the shredded material  7  via the intake tube  15 . Due to the lower specific gravities of the light materials such as upholstery, plastics, and fabric, they are drawn into the intake tube  15 , along with smaller particles of other materials. Heavier materials  17 , such as pieces of metal, pass through the gravity separator  11 . Return air is fed via the exhaust tube  19  back from the cyclone separator  18  to the housing  10 . The intake tube draws approximately 40,000 to 50,000 cubic feet per minute of air to create a vacuum pressure. While the preferred system utilizes gravity separation based on a vacuum force to remove the lighter material portion of the shredded materials  7 , other means could be utilized, if desired. 
   The heavy materials  17 , including both ferrous and non-ferrous, are conveyed to a magnetic separator  20  which comprises one or more magnetic rollers  21 . As the heavy materials  17  pass through the magnetic separator  20 , ferrous metals  25 , which are attracted to the magnetic rollers  21 , cling to the rollers  21  and are carried through the magnetic separator  20  to a ferrous metal discharge stream  25 . While a magnetic drum separator is preferred, those skilled in the art will recognize that other types of magnetic separators can be utilized, if desired. The ferrous metals  25  that are separated are preferably sold for recycling. 
   The heavy non-magnetic materials  26  fall from the magnetic separator  20  onto one or more conveyors  27  and are carried away for further processing. As shown in  FIG. 2 , additional ferrous material fines may be removed from the non-magnetic materials  26  via a magnetic head pulley  33  located on the conveyor. These magnetic fines are preferably added to the light material stream  16 , as shown. Preferably, these heavy non-magnetic materials  26  are moved to a rotary trommel  31  for further separation by screening. The trommel  31  further separates the non-magnetic materials  26  into a component consisting mainly of non-ferrous metals  36  and a component of fine, non-metallic materials  39 . In the preferred embodiment, the trommel  31  has a screen mesh with ⅜-inch openings. Based upon the previous sorting, the fine materials  39  which pass through the screen of the trommel  31  are rendered generally inert due to the surfactant added during shredding, and can be used as an alternate daily or periodic cover for landfills. The remaining component, consisting of mainly non-ferrous metals  36 , is preferably sold for reuse. 
   The light materials drawn into the vacuum air stream of the intake tube  15  are drawn into the cyclone air separator  18 . The cyclone air separator  18  separates the light materials from the air and delivers the air back to the collection housing  14  through the clean air exhaust tube  19 . The light material stream  16 , which can include glass, cloth, rubber, foam rubber, dirt, tar, and plastics, as well as some ferrous and non-ferrous metals, is carried via a conveyor  28  past a cross belt magnetic separator  23  which separates the magnetic materials in the light material stream  16 . The magnetic materials in the light material stream  16  are returned to the magnetic separator  20  via a return conveyor  29 . Alternatively, the magnetic materials could be conveyed directly to the ferrous metal stream  25  that exits the magnetic separator  20 . 
   The remaining light material stream is then conveyed to a rotary trommel  30  for further separation. The rotary trommel  30  preferably includes a ⅜-inch screen and separates the remaining light material stream into a fine material  39 , which includes non-ferrous as well as some ferrous fines, and the coarse material. These fines  39  tend to agglomerate due to the surfactant added during shredding and become generally inert. The fine material  39  from the trommel  30  can also be used as an alternate daily or periodic cover for landfills. The fine material  39  may be further mixed with materials such as construction and demolition debris that have been ground, or any other material such as gravel that has been similarly ground, to provide a material with an overall reduced waste per unit volume of material. 
   The remaining coarse material  35  is further separated utilizing an eddy current separator  32  of the type well known in the art, such as an ERIEZ eddy current separator, to remove non-ferrous metal material  36 . However, those skilled in the art will recognize from the present disclosure that eddy current separators from other manufacturers may be utilized. The non-ferrous metal materials  36  are preferably sold for recycling. 
   The remaining coarse material  37  has been found to have a BTU content which is high enough to be used as a fuel or fuel additive. Testing has shown that this remaining coarse material  37  from the shredded stream of material  7  has a BTU content of 4000 BTU/ton or more, depending on the input stream. In two separate tests, the coarse fuel material had a BTU content of over 6000 BTU/ton, and is preferably in the range of 5000-7000 BTU/ton. This coarse fuel material  37  can be further crushed, ground, or shredded, and additional fines removed, if desired. This allows the now reduced fuel material  37  to be used as a blown-in fuel component. The coarse fuel material  37  may also be utilized as an additive for bituminous coal fired ovens in order to increase the BTU content for certain applications, or may be used directly as a fuel. The fuel material  37  may also be pelletized, if desired. 
   A further step in the process includes separating low density material  40  from the coarse materials  37  with a low density separator  42 , thereby increasing the BTU component content per unit of the coarse materials  37 . More specifically, approximately 35-40% of the volume of the coarse materials  37  comprises low density material  40  such as, for example, foam. The foam  40  within the coarse materials  37  contains, among other things, a substantial amount of air. Removal of the foam  40  from the coarse materials  37  utilizing a low density separator  42  creates denser coarse materials  44 . The increased density of the coarse materials  44  results in a fuel material  44  that has a greater BTU content per unit volume than that of the coarse materials  37  described above. The coarse materials  44  may optionally be blended with combustible materials  46 , e.g., wood chips, in a mixer  48  to achieve a material  50  with either greater BTU content per unit volume or improved chemical properties. 
   The low density separator  42  may remove the foam  40  from the coarse materials  44  in a variety of manners. For example, the low density material  40  and coarse materials  44  may be separated by specific gravity, by cyclone air separation, or by crushing and screening the coarse material  44  to remove the low density material  40 . 
   The foam  40  that is removed may generally range from 1½ inches to 2½ inches in size, or may be smaller or larger than this range. Such foam  40  is a reusable byproduct suitable for a variety of applications. For example, the recovered foam  40  may be used as part of a mixture for use as underlay or covering for flooring material. The recovered foam  40  may also be used as a component of high- or low-density concrete. Furthermore, un-shredded foam (i.e., foam recovered from the stream of recycled material prior to entering the shredder  10 ) may be utilized as a reusable byproduct as described above. 
   The present invention allows the entire stream of shredded material from the recycler to be recycled either for re-use in the case of the ferrous and non-ferrous metals, for use as landfill cover material, or for use as a fuel or fuel additive. This generates additional revenue for the salvage operator, and eliminates the costs previously associated with having to landfill a portion of the shredded waste stream  7 . 
   While the preferred embodiment is used in connection with auto salvage as well as mixed material waste streams which include a mix of metals and plastics, such as metal and plastic furniture, appliances, and/or office equipment, it can be used in conjunction with various other types of manufacturing waste streams which include a mix of metal and plastic materials. 
   While the preferred embodiment of the invention has been described in detail, the invention is not limited to the specific embodiment described above, which should be considered as merely exemplary. Further modifications and extensions of the present invention may be developed, and all such modifications are deemed to be within the scope of the present invention as defined by the appended claims.