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:
(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):
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:
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?
We have a ready capacity to utilize a 5000 inch pound motor from our LifeTrac infrastructure. This can be fitted readily - assumin your bearings and mounting is sufficiently strong.
- what about the cast iron (?) casing with the groove to hold the axle that holds the rollers?
If we could cast iron. We don't have a furnace yet. For now, it's easiest to take heavy steel, such as 1/2" or 1" thick, and weld it together.
- 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
Please look at the structure of the Pelletizer carefully. All it is is a driven flat die (one possible design) with rollers mounted in a fixed position.
The die can be made by taking a piece of 1" steel and drilling 1/4" holes through it. They don't recommend that due to corrosion - but at $20 for one square foot - plus about 4 hours of drilling - I think it's worth it as a first try. That's readily available. Please see if you can look up what a 1 sq foot slab of 1" drillable stainless would be.
For the rollers, I guess that might be the expensive part if we have to machine those grooves at the local fab shop. But, can you find those rollers somewhere?
- anything else, before i start making inquiries from places like http://www.generaldies.com/index.php?blk=dwould ies-and-roller-shells?
Nice. You're ahead of the game. Let's start with the flat die and rollers as on the wiki page. Get a quote. Ask them about the circular dies. We have to evaluate cost, performance, and fabrication simplicity. From the getgo, it appears that the flat die is the easiest system to fabricate.
Are you familiar with QCad]]? If not, download it and learn its basic functionality. There's a free community edition. Then we could start communicating actual designs that we can modify and get feedback upon - especially by that pelletizer company.
Our advantage is that we don't need the gear box. We have one hydraulic motor in the 120 rpm range, and one in the 600 rpm range - usable without gear box. That's a major point in lifetime design, since gears always wear out.
I'm familiar with the cyclone engine. It is absolutely sweet. From what I know, it's a 6 cylinder radial, water-lubricated, high tech engine. It's the best there is.
For our case, if you could work out the pelletizer, or pelletizer-burner like in the cyclone -that would be a major contribution. We could do a system like he did not for $20k, but probably for $2k from pellets to electricity, in a closed system. The steam engine itself shoudl be about $200 in parts.
Anyway, those are some cool videos - they show the possibilities. It does not seem that it would be too difficult to replicate a simple flat-die mill. We can get a good idea on the cost if we get the prices. If we can document that, we can just put a funding basket up on our blog and collect cash for the prototype.
Nick Requesting a Quote
http://generaldies.com " We have a 5000 inch pound motor. Our design is a driven flat die (one possible design) with rollers mounted in a fixed position.
We'd like a quote for 2 or 4 rollers.
Ideally rollers should be roughly this size (about 2 contact with the die maybe?).
To see what I'm talking about http://www.youtube.com/watch?v=AhW4p0tpnAE (put the video to 1:11)
We're interested in quotes on a variety of straight groove types on the rollers. (Nothing undulating or curved for now).
We'd like a quote for your least expensive flat 6 mm-hole carbon alloy die roughly 6 diameter that would work with these rollers. Optionally we're also interested in the price of a stainless steel die of the same kind but correspondingly deeper to maintain the overall integrity of the pellet.
We'd also like to make initial inquiries about a stainless steel 6mm ring die.
Any information that you need to give me a quote, ask me and I will get it to you ASAP. "
Thanks for your inquiry via our website: http://www.ascof.com/Pellet-Mill/Pellet-Dies-Rollers.html
We take this opportunity to introduce ourselves as the largest manufacturer and exporter of flat die pellet mill, machinery and spares from China since last more than 5 years. We are able to supply high quality die and roller for you. Will you advice the specification so I am able to check the cost?
Looking forward to hearing from you.