Biomass Handling Equipment: Wood Pellet Conveyors
August 18, 2015
The tremendous growth of the biomass industry has brought many material handling issues to the fore. Generally, biomass materials fall into the “difficult to handle” category. Biomass materials come in a variety of forms and sizes, with wide ranges of moisture content and bulk densities. Many materials are prone to dusting, and some are hazardous and combustible. This blog looks at the issues surrounding the conveyance of a particular type of biomass material: handling wood pellets via a wood pellet conveyor.
Wood pellets produced in biomass facilities are produced from small wood particles compressed into small cylinders in pelletizing equipment. Depending upon the equipment used, wood pellets can range in size from 6-8mm in diameter, and up to 50mm in length. The pellets retain their cylindrical shape through the binding action of the lignin that is naturally present in the wood.
Wood pellets can be fragile and break apart when conveyed. ( see our Friable Materials page ) The fragility of pellets a key issue to address when considering how to move the material. This issue applies to both producers and consumers of pellets alike. In both cases, particular attention needs to be paid to material transfer points – where the pellets enter and exit wood pellet conveyors – as these are points where the pellets can become degraded through breakage.
Applications involving industrial pellets or standard pellets are more fragile and tend to break up easily. They can also swell and fall apart if exposed to moisture, and may also produce a very fine dust which can present an explosion risk.
In these applications, UniTrak recommends its TipTrakTM bucket conveyor as the solution of choice. Known for their gentle handling of material, TipTrakTM units have been successfully used as wood pellet conveyors in several biomass applications. TipTrak’s are available in both an open and enclosed units. If protecting the material from weather conditions is a concern, then an enclosed unit is your best bet.
In one application, a TipTrakTM S-5 Open unit, with a 5 litre bucket capacity, was used to elevate wood pellets from belt conveyors at three pellet mills into a cooler, at a transfer rate of 955 cubic feet per hour. In this application, the gentle handling of the TipTrakTM is achieved through no transfer points as the pellets moved from the horizontal to the vertical plane during conveying. The gentle handling of the TipTrakTMeliminated the occurrence of any product dusting and degradation, which would have reduced margins for this customer.
Our UniFlex flexible screw conveyors have been used as a feeder for transferring pellets directly into a furnace or boiler, to be burned as fuel. In these applications, custom hoppers are utilized to accommodate the needed material transfer rates. The UniFlex is a good option when requiring wood pellet conveyors to move harder, premium-type pellets, produced for commercial use. The UniFlex conveyor works well in these applications as it can flow material quickly and efficiently to the next point of use.
The proven reliability and gentle handling of UniTrak conveyors make them ideal choices for use as wood pellet conveyors. To find out more about TipTrakTM or UniFlex equipment in biomass and wood pellet conveying applications, please contact our sales department.
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