초록 ▼

A fuel pellet comprises from about 97 to about 99 percent by weight naturally occurring combustible material of which at least 50 percent is natural cellulosic material and from about 1 to about 3 percent by weight synthetic polymeric thermoplastic material. Any balance of the naturally occurring co

A fuel pellet comprises from about 97 to about 99 percent by weight naturally occurring combustible material of which at least 50 percent is natural cellulosic material and from about 1 to about 3 percent by weight synthetic polymeric thermoplastic material. Any balance of the naturally occurring combustible material is filler and is preferably selected from bark, stillage, byproducts of distillation processes, and coal. If old bark, stillage, or byproducts, such as tar and pitch, or coal are used, the amount of the material is limited to 30 percent. The free moisture content of the naturally occurring combustible material is from about 5 percent to about 15 percent by weight, with 10 to 13 being preferred and 10.5 to 11.5 percent being ideal. Substantially all the thermoplastic material is finer than 30 mesh and coarser than 80 mesh. The cellulosic material is no greater than an order of magnitude coarser than the plastic particles and its minimum size is related to bonding requirements between it and the plastic; it is finer than 10 mesh and coarser than 40 mesh. The filler is finer than 10 mesh. The synthetic thermoplastic material is distributed throughout the fuel pellet as discrete particles. A sheath of plastic is on the outside of the pellet. The thermoplastic material is solid at room temperature and has an injection molding temperature of about 95°C. or more. The fuel pellet is made in an extruder where the temperature of the pellet is controlled to assure softening of the plastic within the forming pellet without agglomeration.

대표청구항 ▼

A fuel pellet comprising from about 97 to about 99 percent by weight particulate naturally combustible material, and from about 1 to about 3 percent by weight particulate, synthetic polymeric thermoplastic material, the naturally combustible material comprising at least 50 percent natural cellulosic

A fuel pellet comprising from about 97 to about 99 percent by weight particulate naturally combustible material, and from about 1 to about 3 percent by weight particulate, synthetic polymeric thermoplastic material, the naturally combustible material comprising at least 50 percent natural cellulosic material with any balance being a filler, the synthetic thermoplastic material being distributed as discrete particles throughout the interior of the fuel pellet, solid at room temperature, between substantially minus 30 U.S. standard mesh and substantially plus 80 U.S. standard mesh, and having an injection molding temperature of at least about 95°C., the cellulosic material having a free moisture content of from about 5 to 15 percent by weight, and being between substantially minus 10 U.S. standard mesh and substantially 40 U.S. standard mesh, the plastic binding the cellulosic material together with a mechanical bond by bridging between cellulosic particles and anchoring to the particles, any filler being at least minus 10 U.S. standard mesh. The fuel pellet of claim 1 wherein the thermoplastic material is selected from the group consisting of polystyrene, polyethylene, polypropylene, acrylonitrile-butadiene-styrene, acetal copolymer, acetal homopolymer, acrylic, polybutylene, and combinations thereof. The fuel pellet claimed in claim 1 including a sheath of the thermoplastic material on the lateral surface of the pellet. The fuel pellet claimed in claim 1 including up to about one percent by weight of an alkali silicate selected from the class consisting of sodium silicate and potassium silicate.