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.

Description

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS[0001]Germany Priority Application DE 10 2009 016 470.7, filed Apr. 13, 2009 including the specification, drawings, claims and abstract, is incorporated herein by reference in its entirety.BACKGROUND[0002]1. Field of Embodiments[0003]The embodiments relate generally to a method for producing pellets from prepared biomass in a pelleting press for use as fuel in fireplaces or furnaces. The embodiments further relate to an installation for producing pellets from prepared biomass in a pelleting press for use as fuel in fireplaces or furnaces.[0004]2. Description of Related Art[0005]The production of pellets, also referred to as briquettes or granulates, from fine material or compacted and / or molten material has long been known. Compactors compact material between two rollers, either one or both being formed as a die, and mold the same to form briquettes for use as fuel. Pelletizing by means of extruders and punched disks, optionally with cut...

AI Technical Summary

Benefits of technology

[0018]It has proven to be particularly advantageous that small bodies having a size of 1 mm3 and a higher density relative to the biomass can be detected safely with the aid of a radiography device, preferably a gamma emitter or an X-ray tube assembly. The radiography device preferably disintegrates the weight per unit area of the mat scattered on the molding belt and determines the weight per unit area in the smallest possible grid, for example, of 1 mm2, while the continuously scattered mat passes through the radiography device. The density of usable wood (which is not present in the form of bulk material

Problems solved by technology

Usually, the metering devices used are metering screw conveyors that are, however, not suitable for simultaneously loading several pelleting presses with a constant flow of materials.

However, clusters of material pose problems in the constant supply to pelleting presses since the former are discharged from the conveyor in lumps in extreme cases.

They can even result in problems at the inlet of pelleting presses and a reduction of the maximum throughput per hour if the pelleting presses can no longer comminute the clusters of material or can do so only with great difficulty, and these clusters can block the inlet of the pelleting press on account of their size and can obstruct or even prevent the inflow of biomass into the press gap.

At the same time, the conveyance of lumpy biomass results in a non-uniform loading of the pelleting press which manifests itself, depending on the type of the pelleting press, in increased wear or energy input if irregular driving or compacting forces have to be powered or if locking devices or bearings on shafts are loaded excessively.

The separation of the biomass in the biomass bunker or during its metering to the pelleting press poses an additional problem.

The conveyance of the biomass results in the problem of so-called lumps of uniform material, for example, dust lumps being formed in addition to coarse lumps of biomass.

The problem confronted in major industrial production planning is that in the case of an enlargement of a two-roller press or a pan-grinder press, the supplying metering screw conveyor would have to be

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