OK Mr Takeman, you asked one of the pellet producers to weigh in here. You outlined many of the struggles in making a quality pellet and did a pretty good job of identifying species issues, contamination etc. Along with that all manufacturers struggle with fibre length through their hammermills, moisture contents that vary throughout the year from fibre suppliers. This is regardless of whether it is in house fibre or outsourced. Many factors contribute to quality pellets - Species, contamination, material handling, fibre length, mineral content which can vary depending on the which side of a mountain you are on, soil content, % of heartwood to sapwood, and the list goes on, etc, etc etc. Let me know what else you want to know and I will try and answer your questions. We all have our struggles on a daily basis to make the best possible product that we can. This includes those pellet manufacturers that don't necessarily make the top rated pellets. I don't know of any producer that sets out wanting to make lower grade pellets, they are doing the best with what they have got. We are very fortunate to have some of the most pristine, secure and consistent fibre in the market along with some very talented employees, but make no mistake I respect all of the producers who are trying to make a GO of this industry and we need each and every one of them to make this industry evolve to where it needs to be. The demand for pellets in the world is exponential and many producers will, as you identified, need to access fibre in new places. Thank you for your unbiased reports over the years and your calming efforts when things aren't always perfect.
Thank you for the reply. Glad you joined our group(of misfits) and shared your knowledge with the members. Getting the straight scoop around here is something we really appreciate. We don't often get information first hand and what we do get is often passed down several times. So many things get mixed up or lost. Shall I say we guess at lots of it as well.
Hopefully you can help with this one, I have never understood how they get compression with a straight die. I would have assumed the die would have a slight taper that caused/helped with compression as the fiber gets passed through the die. As long as this isn't a trade secret, I hope you could pass on some insite.
Thanks again and Welcome aboard!
I really need to tour a pellet mill. And shortly after tour a brew pub. That'd be a nice afternoon.
Actually there is a chamfer to the die shape at the contact area (like a funnel) where the rolls press the fibre into the dies and each producer has to find the right die shape specifications for their species, moisture content, time of year, ambient air MC, fibre length, and resin / lignin content etc to get the best pellet. For example we actually change our die length from summer to winter.The angle of the taper is crucial as it effects the compression ratio as the material is forced into the die holes by the rollers during pellet press operation. Each material is different and you require a different angle for say wood and animal feed. Say for instance you didn't put any taper on the holes and it was just a vertical compression. This maybe ideal for some forms of animal feed which you do not want to be compressed too much as the animals will not feed on pellets which are as hard as rocks. However say you tried to run sawdust through that same die to produce wood pellets. The result would be no pellet at all as there was no horizontal force to build pressure to heat the wood, to melt the lignin. Therefore a wood pellet mill die will have a taper on the holes. However if the taper is too shallow the forces the die generates will be greater than the pressure the roller can apply, this will lead to a blocked die
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