Continuous pelletizing, drying and bagging systems with improved throughput

Abstract

The various embodiments of the present invention are directed to improved processes and systems for continuously bagging materials. In particular, the improved processes and systems can be used to bag tacky materials with improved throughput. The systems generally include at least one of a feeding section, mixing section, pelletizing section, transport piping, agglomerate catcher, defluidizing section, drying section, pellet diverter valve, and/or bagging assembly.

What is claimed is: 
     
         1 . A system for continuously bagging tacky materials, the system comprising:
 a feeding section configured to receive a material, wherein the feeding section is optionally thermally controlled;   a mixing section configured to receive the material from the feeding section and mix, melt, and/or blend the material, wherein the mixing section comprises a die;   a pelletizing section configured to receive the material from the mixing section and pelletize the material, wherein the pelletizing section comprises:
 a cutter hub comprising a blade angle of less than about 90 degrees; and 
 a transport fluid box comprising an inlet and an outlet to reduce a velocity of transport fluid into and through the transport fluid box, wherein the outlet reduces any obstruction of pellets leaving the transport fluid box by providing an open area; 
   a system of non-linear transport piping downstream of the transport fluid box;   an agglomerate catcher downstream of the pelletizing section, wherein the agglomerate catcher comprises an angled agglomerate removal grid, and wherein the non-linear transport piping is configured to allow transport of the material from the pelletizing section to the agglomerate catcher;   a defluidizing section downstream of the agglomerate catcher, wherein the defluidizing section comprises a pellet feed chute;   a drying section configured to receive the material from the defluidizing section and dry the pelletized material, wherein the drying section comprises a dryer having at least one circumferential screen about a rotor;   a pellet diverter valve downstream of the drying section, wherein the pellet diverter valve comprises:
 an inlet configured to receive an incoming flow of pellets from the drying section; and 
 at least a first and second outlet, each configured to dispense an outgoing flow of pellets; 
   at least a first and second bagging assembly in communication with at least the first and second outlets of the pellet diverter valve, respectively, wherein the at least the first and second bagging assemblies are configured to alternatingly receive a specific quantity of pellets from the pellet diverter valve to allow continuous bagging of the pellets; and   a surface treatment applied to at least a portion of a surface of a component of the feeding section, mixing section, pelletizing section, transport piping, agglomerate catcher, defluidizing section, drying section, pellet diverter valve, and/or bagging assemblies to reduce abrasion, erosion, corrosion, wear, and undesirable adhesion and stricture, wherein the surface treatment comprises at least two layers such that the surface formed following treatment is three-dimensionally textured, wherein the at least two layers comprise at least one layer of a wear-resistant material that is uniformly overcoated with a non-stick polymer that only partially fills the three-dimensional surface texture of the at least one layer of wear-resistant material.   
     
     
         2 . The system for continuously bagging tacky materials of  claim 1 , the mixing section comprising a die comprising a removable insert. 
     
     
         3 . The system for continuously bagging tacky materials of  claim 2 , wherein the removable insert has a taper angle that is less than or equal to about 25 degrees. 
     
     
         4 . The system for continuously bagging tacky materials of  claim 2 , wherein a gap between the removable insert and a body of the die is less than or equal to about 0.010 inches. 
     
     
         5 . The system for continuously bagging tacky materials of  claim 2 , wherein a face of the removable insert extends beyond a surface edge of a body of the die less than or equal to about 0.080 inches. 
     
     
         6 . The system for continuously bagging tacky materials of  claim 1 , wherein the mixing section comprises a die comprising a removable insert with a taper angle that is less than or equal to about 10 degrees, wherein a gap between the removable insert and a body of the die is less than or equal to about 0.005 inches, and wherein a face of the removable insert extends beyond a surface edge of the die body between about 0.060 inches and about 0.080 inches. 
     
     
         7 . The system for continuously bagging tacky materials of  claim 1 , wherein the cutter hub is streamlined to have an extended hexagonal cross-section. 
     
     
         8 . The system for continuously bagging tacky materials of  claim 1 , wherein the blade angle of the cutter hub is between about 20 degrees and about 60 degrees. 
     
     
         9 . The system for continuously bagging tacky materials of  claim 1 , the cutter hub further comprising a blade cutting angle that is less than or equal to about 15% less than the blade angle. 
     
     
         10 . The system for continuously bagging tacky materials of  claim 1 , the cutter hub further comprising a blade traverse angle that is between about 20 degrees and about 55 degrees. 
     
     
         11 . The system for continuously bagging tacky materials of  claim 1 , wherein the cutter hub comprises a blade angle of about 30 degrees to about 50 degrees, a blade cutting angle less than or equal to about 15% less than the blade angle, and a blade traverse angle of between about 20 degrees and about 55 degrees. 
     
     
         12 . The system for continuously bagging tacky materials of  claim 1 , wherein the die of the mixing section comprises a die hole having a land that is continuous. 
     
     
         13 . The system for continuously bagging tacky materials of  claim 1 , wherein an angle of inclination of the angled agglomerate removal grid is at least about 20 degrees. 
     
     
         14 . The system for continuously bagging tacky materials of  claim 1 , wherein an angle of inclination of the angled agglomerate removal grid is at least about 50 degrees. 
     
     
         15 . The system for continuously bagging tacky materials in  claim 1 , wherein the at least one layer of wear-resistant material of the surface treatment is a ceramic. 
     
     
         16 . The system for continuously bagging tacky materials of  claim 1 , wherein the non-stick polymer of the surface treatment is a silicone, fluoropolymer, or a combination thereof. 
     
     
         17 . The system for continuously bagging tacky materials of  claim 1 , the drying section further comprising rotor blades in an upper portion of the rotor that are at least about 20% narrower than rotor blades of a lower portion of the rotor. 
     
     
         18 . A method for continuously bagging tacky materials, the method comprising:
 feeding material into a feeding section, wherein the feeding section is optionally thermally controlled;   mixing, melting, and/or blending the material at a mixing section, the mixing section also extruding the material through a die;   receiving, at a pelletizing section, the material from the die of the mixing section, the pelletizing section pelletizing the material, the pelletizing comprising:
 cutting the material by a cutter hub to form pelletized material; and 
 receiving, by a transport fluid box with transport fluid therein, the pelletized material; 
   transporting, through a system of non-linear transport piping, the pelletized material;   removing, by an agglomerate catcher, agglomerate in the transport fluid, wherein the agglomerate catcher comprises an angled agglomerate removal grid, and wherein the non-linear transport piping transports the pelletized material from the pelletizing section to the agglomerate catcher;   defluidizing, by a defluidizing section, the pelletized material;   drying, by a drying section, the pelletized material;   diverting, by a pellet diverter valve, the pelletized material into a first bagging assembly or a second bagging assembly; and   bagging, at the first and second bagging assembly, the pelletized material in a manner that enables continuous bagging of the pellets.   
     
     
         19 . The method for continuously bagging tacky materials of  claim 18 , wherein the pellet diverter valve diverts the pelletized material into the first and second bagging assemblies in an alternating manner. 
     
     
         20 . A pellet bagged by the method of  claim 18 .