Nick on the Pelletizer

this is essentially a book report with some supporting youtube videos (the book is here). you probably already know most of this stuff so feel free to skim but the attached book is pretty detailed as support for these ideas.

the complete pellet factory would involve

-(optional) chipper for large biomass -(optional) shredder for biomass greater than 1 inch diameter -(optional if feedstock is already less than the diameter of the die) a hammer mill rated for wood chips with screen to guarantee particles less than the diameter of the die (the example of 6 mm was given but i don't know yet) of the pellet mill

-***at the very least a mulcher with a screen***

-(probably optional, depending on feedstock) a cyclone separator (google products search for "cyclone separator" yields several from $100-250) to suck the milled wood dust (or other biomass) into

-***a hopper which could in the future could be fitted with an auger***

-(optional) said auger which takes the biomass to -(optional if other drying methods, such as producing pellets from pellets, solar drying, etc are employed) a long rotary drum dryer (perhaps several oil barrels welded together connected to a [waste] heat source)---a steam pellet stove or the condenser/radiator/heat exchanger from a closed loop steam engine (such as http://www.youtube.com/watch?v=BLst-kslKio) could also work -(optional) another cyclone, necessary to maintain even drying within the drum dryer

-***(can be done by manually adding vegetable oil or other binding agents and stirring by hand)*** but in the future would be automated by upgrading to a large mixing vat with injection of binding agents, water from e.g. peristaltic pumps or heat from e.g. dry steam ("recipe" variable depending on type of biomass and the batch's overall method, and sometimes not employed at all)

-finally, ***the actual pellet mill itself***, or pellet mills run in series to reform pellets (drying and mixing), or in parallel (scalability of output) (discussion of which dies and rollers to use in constructing this follows and more information is in the book in "Step Six: Pellet Production")

so all that's needed to start are 1) a mulcher, 2) a hopper, 3) a pellet mill capable of handling as large a variety of biomass as possible, 4) the feedstock of biomass and binding agents and a research program for learning to dry and mix for different feedstocks. many upgrades are made possible after that via hopper-to-auger or cyclone-to-hopper connections.

it would start out looking like this:

http://www.youtube.com/watch?v=BV1HJ7klm6I

(together with a hammer mill)

ultimately such a system can probably scale up to something like this (please note hopper-to-auger and cyclone separator-to-hopper connections):

http://www.youtube.com/watch?v=OxChBQf-PLI

engineering issues for the pellet mill itself

-a flat die instead of annular die should be used (more friction/heat, simpler to assemble and disassemble, cheaper to source parts, small to medium design as opposed to medium to large design, greater variety of biomass support)

-the die should be stainless steel or chromium (probably stainless steel because of cost and size/weight since a deeper die is needed when there is a high finish as in chrome) instead of carbon steel (corrosion issues) for longer lifespan

-rollers should have tapered protrusions (see video below) to eliminate abrasion/degradation problems from varying distances traversed by round roller over flat die, which is the only substantive advantage of annular dies (there are many different roller designs and their benefits will have to be studied but some kind of tapering seems likely). allegedly these wear-and-tear problems can be eliminated almost entirely through proper engineering

for a look inside a small, flat die pellet mill with some kind of tapering on the rollers and discussion of its power source, see:

http://www.youtube.com/watch?v=AhW4p0tpnAE

questions for you

from the video, what can you say about about the motor / power source in terms of FeF's capabilities, connection points, o-rings (or whatever they're called), anything i need to know etc.? is this analogous to a power take-off? is it like the motor from a lathe?

what about the cast iron (?) casing with the groove to hold the axle that holds the rollers? metal casting is probably not possible right now at FeF i assume. is there some name i can probably google things like this under? i don't know what this casing might be referred to as or how to source one

anything else, before i start making inquiries from places like http://www.generaldies.com/index.php?blk=dies-and-roller-shells?

Cheers,

Nick Person