Yearly Archives: 2014

DETERMINING THE NATURAL COMPACTION OF A BIOMASS PILE

Paul Janzé – Advanced Biomass Consulting Inc.

For many reasons, people need to know how much material is present in a biomass storage pile. Hog Fuel Storage, 2Accurate volume measurement is relatively easy, but to determine the amount of dry fibre actually present, the compacted density and moisture content are required. In fact, the greatest number of queries I receive at this website are with regard to biomass pile density and compaction. This is because compaction is the most difficult pile parameter to determine with any consistent accuracy.

Biomass is highly compressible both through artificial and natural means. Every material is different and every pile is different.  The amount of compaction depends upon the species, the form of the material, the relative amounts of bark, wood and foliage present, the grind size, particle size distribution, moisture content, weather conditions, the shape of the pile, how the pile is constructed, how long it has been sitting, the amount of decomposition, the amount of contamination with dirt, grit or stones, etc. So, it is just an educated guess as to how much compaction there will be in any one pile. Continue reading →

Helical Chute for Wood Pellets

Paul Janzé – Advanced Biomass Consulting Inc.

Introduction

Some materials such as wood pellets are quite fragile and tend to break up when handled. ABC - Helical Chute,2Wood pellets are manufactured from small wood particles, generally <3.0mm (<1/8″), which are compressed in pelletizers into small cylinders 6-8mm in dia. x up to 50mm long. Pellets are held together by the binding action of the lignin that is naturally present in the wood fibre, acting under pressure. From the moment they exit the pelletizer and fall into the receiving conveyor, the pellets start to break up. At every conveyor transfer point, in bucket elevators, screw and chain conveyors, falling into bins, loading into trucks, railcars or ships, they degrade some more. Every time they are handled by crane or mobile equipment, they break up a bit more into their constituent parts. The best way to reduce product damage and small particle generation is to handle the pellets as gently as possible. Falling >30m (100′) into a silo results in high velocity impact forces, breakage and dusting. Consequently when faced with the problem on a recent project, we developed a spiral / helical chute which allows pellets to slide rather than freefall to the bottom of a silo.

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DISC SCREEN FUNDAMENTALS

Author: Paul Janzé, Advanced Biomass Consulting Inc.

Sliver Screen2The disc screen is a simple piece of equipment that is ideal for, and commonly used for screening woody biomass. It consists of a series of driven shaft assemblies mounted in a frame.  Each rotor shaft assembly has profiled discs mounted at regular spacings. The discs from one shaft interleaf with those on the adjacent shafts, creating open areas between the discs and the shafts.

Incoming material is fed onto one end of the screen.  The shaft assemblies rotate, and the discs agitate the material. Pieces of material that are smaller than the spacing between the discs and shaft assemblies fall through the screen.  The pieces that are larger than the openings are conveyed along the top of the discs and pass over the end of the screen.

Disc screens are particularly useful for screening biomass for the following reasons: Continue reading →