Woodmizer Sawdust Burner . . . . .

slowzuki · April 12, 2007, 08:21:53 AM

The power depends on how fast you turn it, it will take some torque. If you had no spacers you would need a big shaft. The spacers end up giving the shaft stiffness. At low speed the vibs wouldn't be bad.

The tighter the blades (thiner spacers) and higher the tooth count the slower the self feeding and less hp it would require. Of course then it would be really slow self feeding dry hardwoods.

I think the biggest challenge is keeping the blades from rotating on the shaft. Easy answer is to drill a hole in the body and run a pin through the whole pack but then you can't just grab an off the shelf blade. The diamond shaped drive solves it but is rare nowadays on cheapy blades.

Re running it angled, the teeth are too aggressive on a single blade and it would bind from self feeding too fast or gravity or force feeding to fast.

Quote from: Cedarman on April 11, 2007, 10:36:27 PM
It is going to take a good bit of power to run those saws. I did what you are saying with a gangrip and 15 hp motor. I didn't use spacers, but i would like to try it. You are going to have a big mass of steel spinning if you have 8 or 10 inches of blades and spacers. I would think an 1 1/2" shaft at least. Also, it has got to be balanced or vibration will be horrendous, unless operation at lower speeds.

twobears · April 15, 2007, 08:25:25 PM

one thing i,ve been wondering is just how big a slab this thing should be made to handle???
i have a little bitty hud-son oscar 18 bandsaw and i have some pretty wide slabs.i put the tape on a few and some are 16 inches wide and up to four inches thick.

delbert

PS:where,s the best place to order cheap table saw blades in bulk??

Bioman · April 16, 2007, 11:55:01 PM

Got a call from one of the 25th tour attendees from California today. Says he figured out how to make up to 200 lbs / hr of dust from slabs with 1 1/2 hp. He's sending dust sample tomorrow for review. He didn't say how he did it, but he sounded pretty excited about it.

Anyone else come up with ideas or try it yet?

twobears, i'll check into buying blades in bulk with some of our vendors.

beenthere · April 17, 2007, 12:12:52 AM

Bioman
Enjoyed your presentation at Wausau show Saturday. Turned out to be a great day. Probably not so great for all you folks setting things up for us. That was a big crowd of around 700 registrations, I heard.

Burlkraft and I wondered on the way home if a Ag hammermill would hog some biomass down to biodust. Probably you've tried that equipment. I shoveled a lot of ear corn into one, but don't know how they'd work with an oak slab....or edging.......or chips.

Bioman · April 17, 2007, 08:53:48 AM

We haven't purchased our own yet, but it appears that through limited testing an AG hammermill with a 1/4" screen would work fine. I screened the chips (1/4) we ran through the Bearcat and burned them wet yesterday.

Thanks for coming to the Wausau show. It was a pleasure meeting you. You are right, it was a good day. It's always fun to get together with so many people with common interests.

I saw someone else with a Forestry Forum hat on, but didn't get a chance to say hi. He had a camera on me so I'm guessing he knew who I was. Did I hear there were 5 guys there who frequent the forum?

We posted a bunch of pictures from the show on the Wisconsin link of the www.biomizer.com site. You may find yourself in there somewhere.

thecfarm · April 17, 2007, 09:52:29 AM

Bioman,for pictures go up to "help" on top of the page.There is something there about posting pictures.Looks like a lot at first,but it's not.Just follow it STEP by STEP.If I can do it,anyboby can.Seems like I had some trouble,but I asked a question and I was put on the right track.It gets alot easier the more you do it.

pineywoods · April 17, 2007, 09:59:17 PM

bioman----re using the burner to generate electrical power... You may be aware of this, but if not, here's something worth checking into::couple of years ago NASA (yeah, the aerospace guys) had a small back-burner project to develop a modernized version of a sterling cycle power plant. They had a working version stuffed under the hood of an old dodge pickup truck. I would guess at least 100 hp, it motivated the old dodge quite well. The powerplant was a completely sealed unit, just apply heat (they used an oil burner) and the output shaft started turning. The nice thing is--since it was developed using our tax money, the technology is public domain, free for the asking. NASA has a technology transfer operation somewhere in the organization, a few phone calls and some browsing on their web site (www.nasa.gov) might be worthwhile.

submarinesailor · April 18, 2007, 07:26:59 AM

Back in 1998, I was involved in a demonstration project at the Pentagon where we used solar energy to drive a sterling power generator. Basically it was a convixed disk array focused on a heat receiver that transferred the heat to the sterling, which in turn drove a 25KW genset. And the real neat thing about this setup was that it could be powered by natural gas or propane when there was no/not enough sunlight.

Check out the article in the FEMP FOCUS magazine: DOE FEMP Magazine link

Bruce

Bioman · April 19, 2007, 09:19:46 AM

Just wanted you guys to know I'm not ignoring your threads. I've been diverted to a different product line for the past few days (Lastec lawnmowers www.lastec.com). We're introducing articulating mowers that range from 61,73,80 and 100". Lot's of last minute details....

I'll get back to your posts as soon as we get the guys on the road to the MO show this weekend.

Bioman · April 24, 2007, 04:48:55 PM

Thanks for the info on power generation - a lot of effort has gone into the Stirling technology; I hope it pays off some day.

Here's a link to the company we worked with for several years. Most of the accomplishments they have posted were done while we were involved. It seems they haven't worked on the 1kw generator since then. Most of their success has been in the micro refigerators. I notice NASA references the same technology.

Bioman · April 25, 2007, 04:12:58 PM

I notice the link was not attached

http://www.gocpc.com/

Interesting history of wood gas - a surprising number of people don't know how widely the technology was used until natural gas and petrol became cheap

http://www.woodgas.com/history.htm

Another little known technology is torrefication

http://hem.fyristorg.com/zanzi/torrefaction.html

The company we visited was big into torrefication for cook stoves to be used in poor countries

LT40HDD51 · May 04, 2007, 09:39:20 PM

Very interesting... I knew you were working with someone on this before, but that was about it. I cant wait till you get this all figgered ;)

Bioman · May 07, 2007, 01:49:44 PM

Things are still going well - just got back from our PA show where about 500 people attended. Interest continues to be high and seminar sessions are well attended. The main opportunity still points toward grinding technology for slabs and other biomass products.

You asked about cogen - The goal is 5 kw on the first pass. Voltage will be 220 (or whateveryou need in Canada). I can't give you a time frame at this point. We will be back on this project later this year.

For those who are wondering:

It will require approx 100,000 to produce 5 kw at 17% efficiency. Most of the losses are related to the latent heat of condensation. So, if we use the condensation heat can to heat a building, structure, kiln etc, the overall efficiency becomes quite high. Sounds like another win-win for most who would use this technology.

We're currently building the 1,000,000 BTU unit for kiln use right now. I'll post pictures one of these days.

Any specific pictures of items any of you would like to see? I may chose not to post pictures of some of the inner workings, but most of it is available.

slowzuki · May 08, 2007, 08:26:47 AM

I've got a question I have not seen an exact description off: Does the unit atomize the dust ie blow the dust in suspension with air like a coal boiler or is the dust in a burn cup? My guess from the diagrams is there is a cyclone the dust is introduced into but there must be a pilot or similar.

LT40HDD51 · May 08, 2007, 09:47:37 AM

Id like to see anything of the cogen unit... maybe a pic of the current 1 000 000btu burner... oh, whatever you have handy ;D

220 would be great, we use the same voltages and frequency you guys do (except for 3ph). Any plans at all for a dc model? 12, 24, 48v... Im thinking battery/inverter scenario... https://forestryforum.com/board/index.php?topic=23511.0

Bioman · May 08, 2007, 10:54:40 AM

Here's a rendering of the fuel injection / anti-burnback system. The fuel is dropped into an airstream that creates a venturi that pulls fuel from the feed tube and then creates the circular air flow in the chamber. We're applying for patents on a few items and this is one of them. It appears to be nearly impossible to burn back into the fuel tube with this configuration. When the machine is off, air drafts through the injection blower keeping all of the outer tubing cold.

It is this configuration that creates the quick and complete burn of the biodust. Dust does not get a chance to sit around and smoke or create clinkers while air is blown across the ashes.

Bioman · May 08, 2007, 11:26:54 AM

Sorry, the previous picture is a little dark - I can repost if you need me to.

Here's a rendering of the 1,000,000 BTU unit that we're building right now. The fuel bin system is not shown as that is the part we're still working on.

Voltage will probably be DC inverted to AC. Too early to talk too much about this side of the project.

Jeff · May 08, 2007, 11:37:26 AM

Bioman, actually the photos are sharp and perfect. If they are appearing dark on your monitor, your monitor might be getting tired. I see that on here quite often where a members photos keep getting lighter and lighter then too light then you hear their monitor went kaputt.

Bioman · May 08, 2007, 11:49:03 AM

Great, thanks.

slowzuki · May 08, 2007, 02:24:32 PM

My next question is with the high combustion velocities, are you bothering to try to collect flyash or are you just sending it out the stack? My jetstream boiler burns very clean but has embarassingly high very fine particulate emissions.

Bioman · May 08, 2007, 02:45:38 PM

Very little flyash associated with WM-type sawdust. Wood flour (40 mesh) has a little but not very noticeable unless burning inside the building (not recommended). We do have some flyash with shredded magazines - however it certainly isn't an embarrasing amount.

I am not at liberty to show you the internal workings of the combustion chamber yet, however I can tell you the configuration reduces the problem significantly. Flyash collects on horiontal surfaces in the hx, but we are allowing easy access for maintenance.

LT40HDD51 · May 08, 2007, 07:48:40 PM

I just hit Wikipedia for a lesson on BTUs. Are we talking BTUs/hour? How many BTUs will be used by the generator? Can more than one generator be used on one burner without losing too much heating capacity, or at all?

Bioman · May 08, 2007, 07:51:45 PM

Yes, that would be BTU's/hr.

Using the math I proposed earlier, we could run the burner at 150,000/hr and generate 7.5KW and have 120,000 BTU left to heat a structure of some kind.

LT40HDD51 · May 08, 2007, 08:18:57 PM

Ok, so one million BTUs is wide-open, and it runs at whatever rate it needs to supply the heat being drawn?

Quote from: LT40HDD51 on May 08, 2007, 07:48:40 PM
...Can more than one generator be used on one burner...?

Bioman · May 08, 2007, 08:58:54 PM

The capacity of the cogen module will be limited by gas potential and motor size of the module itself. A nominal amount of heat will be required to run the motor - in this case 100,000 btu for 5 kw. If you were burning at the rate of 1,000,000 btu's the excess heat would go out the flu or to some other use - you would still only get 5kw and the requirement to run the motor would only be 100,000 btu's. In theory, multiple modules could be fed by the 1,000,000 btu burner.