Method and Installation for the Production of Pellets from Biomass in a Pelletizing Press for Use as Fuel in Furnaces

Abstract

A method and an installation for producing pellets from prepared biomass in a pelleting press for use as fuel in fireplaces. The biomass is made of fibers, shavings or chippings containing cellulose and/or lignocellulose, with or without a binding agent and/or additives, and after being prepared is stored in a biomass bunker. The method includes: biomass discharged from the biomass bunker into a scatter device, a mat made of the biomass having a substantially uniform weight per unit area formed by the scatter device on a molding belt, the mat produced on the molding belt examined by an examining device for defective spots and/or foreign substances, and the mat supplied to a pelleting press. At least parts of the mat or a section of the mat include defective regions and/or foreign substances separated from the method upstream of the pelleting press.

1 . A method for producing pellets from prepared biomass in a pelleting press for use as fuel in fireplaces, the method comprising the steps of:
 preparing the biomass, the biomass being made of fibers, shavings, or chippings containing cellulose and/or lignocellulose;   storing the biomass in a biomass bunker following the preparation of the biomass;   discharging the biomass from the biomass bunker to a scatter device;   forming, on a molding belt by using the scatter device, a mat made of the biomass and having a substantially uniform weight per unit area;   examining the mat formed on the molding belt for defective regions and/or foreign substances using an examining device;   supplying a first section of the mat to the pelleting press; and   separating a second section of the mat having the defective regions and/or the foreign substances from the production of the pellets upstream of the pelleting press.   
     
     
         2 . The method of  claim 1 , wherein the examining and separating steps include determining and separating mat irregularities having properties that are detrimental to the pelleting press, the irregularities including the defective regions, the foreign substances, inhomogeneities, and/or excessive density. 
     
     
         3 . The method of  claim 1 , wherein the examining device comprises a weighing device and/or a radiography device. 
     
     
         4 . The method of  claim 3 , wherein the examining step includes using the radiography device to determine a weight per unit area of the mat in a grid of a square millimeter in order to detect the defective regions or the foreign substances. 
     
     
         5 . The method of  claim 1 , further comprising removing the second section from the molding belt and/or transferring the second section to a refuse chute. 
     
     
         6 . The method of  claim 1 , wherein the separating step includes transferring the biomass to a refuse chute using pneumatic nozzles, a switching system, and/or a molding-belt retraction system. 
     
     
         7 . The method of  claim 1 , further comprising disintegrating the biomass of the mat using a milling roller positioned at an end of the molding belt and/or using a disintegrating device disposed upstream of the pelleting press and in a direction in which the biomass falls. 
     
     
         8 . The method of  claim 1 , wherein the preparing step includes sieving the biomass to a screening mesh width size of more than 0.33 mm. 
     
     
         9 . The method of  claim 1 , further comprising passing the mat through steam in a vaporization device. 
     
     
         10 . The method of  claim 1 , further comprising compacting the mat on the molding belt using a prepress. 
     
     
         11 . The method of  claim 1 , wherein the pelleting press includes an extruder press, a two-roller press, or an annular die having at least one inwardly or outwardly disposed pan-grinder roller. 
     
     
         12 . An installation for producing pellets from prepared biomass in a pelleting press for use as fuel in fireplaces, the biomass being made of fibers, shavings, or chippings containing cellulose and/or lignocellulose, with or without a binding agent and/or additives, the installation comprising:
 a biomass bunker for storing the biomass following the preparation of the biomass;   a scatter device disposed downstream of the biomass bunker;   a molding belt disposed at a discharge side of the scatter device, wherein the molding belt is configured to rotate horizontally endlessly, and wherein the scatter device is configured to form a mat on the molding belt;   an examining device disposed in a region of the molding belt, wherein the examining device is configured to examine defective regions and/or foreign substances included in a mat; and   at least one device disposed upstream of the pelleting press, wherein the at least one device is configured to separate at least parts of the mat or an entire section of the mat that contains the defective regions and/or the foreign substances.   
     
     
         13 . The installation of  claim 12 , wherein the examining device comprises a weighing device and/or a radiography device. 
     
     
         14 . The installation of  claim 13 , wherein the radiography device is configured to determine a weight per unit area of the mat with a resolution of 1×1 mm for detecting the defective regions and/or the foreign substances in the mat. 
     
     
         15 . The installation of  claim 12 , further comprising a molding-belt retraction system, a suction device, and/or a removing device disposed in a region of the molding belt, wherein the molding-belt retraction system, the suction device, and/or the removing device are configured to dispose of the defective regions and/or the foreign substances of the mat in a refuse chute. 
     
     
         16 . The installation of  claim 12 , further comprising a pneumatic nozzle, a switching system, and/or a suction device disposed in a further production process located downstream of the molding belt and wherein the nozzle, the switching system, and/or the suction device are configured to separate the defective regions and/or the foreign substances in the mat. 
     
     
         17 . The installation of  claim 12 , further comprising a disintegrating device disposed between the molding belt and the pelleting press, wherein the disintegrating device is configured to disintegrate falling biomass. 
     
     
         18 . The installation of  claim 17 , wherein the disintegrating device comprises at least one disintegration roller including a spoke roller. 
     
     
         19 . The installation of  claim 12 , wherein the pelleting press comprises an extruder press, a two-roller press, or an annular die having at least one inwardly or outwardly disposed pan-grinder roller. 
     
     
         20 . The installation of  claim 12 , further comprising a vaporization device disposed in a region of the molding belt. 
     
     
         21 . The installation of  claim 12 , wherein the molding belt comprises a screening belt configured to perfuse the molding belt. 
     
     
         22 . The installation of  claim 12 , further comprising a prepress disposed in a region of the molding belt.