Hi April,
I guess you’r right about briquetting and also pelletizing helps a lot
In the past i did develop briquetting equipment, dryers and so on, anything for recycling.
Now i enjoy with that knowledge, it can be done…
At the bottom line its always economics, then comes ecological but only few practical builds…
I guess its time for a positive change…
You are running on woodgas constantly ? You have a lot of sawdust? Lets try to find an easy, cheap economical ecological way to do… be it only on paper first…
But it would benefit a lot of people, first place who already are do ers…
Lets fit the pieces of knowledge together and find solutions (always been my passion)
We are a group including chemical, design, and computer modeling engineers, and a good bit of our data is locked under non-disclosure. Most general information I have no problem sharing with anyone. I just mentioned that “yes, it can be done with sawdust”, but to be honest it was problematic on our first and only day to trial run all day on it. I saw nothing, however, that some more hard work and banging my head against the wall can’t fix.
I run almost every day, but am still in testing. We have lots of fuel from the mill. Scabs, shavings, and sawdust. Approximately 300 tons annually.
We joined driveonwood because we are interested in vehicular use also, but rather than re-design the wheel we thought Wayne has obviously done well with his designs so…
I know of very few who are capable of doing the sawdust, even when briquetted, successfully, especially on a commercial scale like a lumber mill would require. Upon combustion all those little bitty pieces you compressed into briquettes once again become little bitty pieces. Lots of mass/flow issues. Residence time issues. I would put trying to burn loose sawdust over into the insane column. But maybe someone is doing it. Somewhere. On a commercial scale. That has a monetary pay back. One good picture of this is that the economics are so tight, the system is so expensive, that when everything is designed and tested, just having an operator standing there running the thing can break the budget. It has to be hands off, with a trained operator somewhere close by but only if needed. He would have to earn his living with something other than the gasifier, and use it only as a pay perk someway or other. A friend of mine is doing a multimillion dollar bio-fuels plant with a gasifier as one small part of the overall system. His words, “I ain’t got it in my budget to pay someone to babysit this damn thing.” It is really tight economics, and to be commercially viable, must be virtually hands-off in operation. Not an easy task. We’ve been on this over four years now and just recently saw mill equipment running on the sawdust it produced. That in itself was very satisfying to see, but personal satisfaction of accomplishment does not, in itself, pay any bills.
Hi April
Thanks for posting.
Do you have some photos or video of you set up?
As they say a photo paints thousand words.
Your briquette machine, do you briquette wet saw dust or dry ?
Do you use a binder in the process?
Is the press heated , to allow the lignates in the wood to do the bonding/ binding of the sawdust ?
What size is your shavings and briquettes ?
Hi April, Patrick,
Compressing briquettes without binder, without heating works ok.
Moister content max 18%
Hydraulik press, pressure needed per cm2 = 1,2 metric tonnes
I was also wondering if briquettes from this density can be gasified
I have done testing in the states in georgia and louisiana, both making briquettes from paperdust.
Also pine wood and pine needles are very good for making briquettes.
I have data available, no comercial interest my side.
Let me now per pm if you want to know.
Regards
Koen
Patrick,
We compact dry, low moisture sawdust. Koen is right in the ballpark about the max moisture content… I would have to see what the actual hydraulic pressure is that we are running now (we adjust the pressure relative to our humidity of fuel and atmosphere). We are in a high humidity area, and if the machine is shut down overnight without a cap over the expulsion tube the briquettes can swell up and require drilling out. Not fun. We tried binders, but applying too much liquid of any sort (we used glycerin) became like trying to squeeze oatmeal. Plus ANY additives to the fuel can drastically influence how they combust and flow. They seem to work just fine dry using the heat of compression to “melt” the lignin enough to bind. I am told that screw types work better at creating this heat than hydraulic. I will take a good photo of the briquette machine today and post it. I did a video yesterday evening late of the engine running and extra gas flaring, but as I think I mentioned there was a dramatic change in flare color, I think which will turn out to be from more fines being swept along with the gases. My filter inspection should address that today. Hopefully the video will turn out good and I can post that. Nothing top secret about an old ford engine, lots of plumbing, and a flare, haha. I’m not here to make money on this forum, just to share what I can with those who might need encouragement or possibly a warning of a path better not traveled. Actual experience is the best teacher. Best advice I can come up with is to learn not to scratch your nose while you’re in the shop. We get a good laugh on each other seeing the carbon soot face painting.
If you are seriously interested in pursuing this I would start by figuring just how much energy you have in your waste, convert that to potential electrical output, calculate the value of that electricity (varies a lot depending on where you are), start balancing that against your costs, investments and figure your payback on it all. It is tight economics. Doug Williams has excellent information on all this.
Also to take into consideration is the type of gasifier design. Very very few people can gasify densified fuel with the typical Imbert variations. You might find some that do, but most just steer away from it if they have a good performing gasifier that works well with chips or chunks. Much easier to stay with the normal fuels here. But you are locked in, it seems, with your sawdust. I would recommend either a stratified or a linear hearth design…after you get your briquetting down pat. (probably find one for about 10 grand) You’re either going to have to become seriously dedicated to your task and work through all the design yourself or be wealthy enough to purchase something on the market at very high prices and hope your payback calculations are correct. Be careful if you go that route because there are many snake-oil salesmen in this business. I would recommend studying Mukunda and his stratified designs.
Unruh touched on something that might be of interest. Using electric motors to produce the waste to produce electricity to run the electric motors. I would assume he was tossing out the idea that perhaps some of the equipment might be driven off gas engines instead of electrical motors. Might be a good idea since the mill operator would basically be the essential gasifier expert on hand. You can tell from the sound of the engine what is going on inside the gasifier after you become familiar with it.
Also keep in mind that if you tie into the grid you will be dealing with the utility companies. They are, for the most part, unfriendly at best and have been known to make the project basically impossible. That is in their interests to do so. Not always the case, but is the norm. There is a divide between home usage and commercial usage. The guy who wants to power his house or cabin is just fun and games, the guy who wants to power his industry is competition.
Koen,
I walk through pine needles every day and want to try some in the briquetter just to see. And pine cones! Would need a hog grinder plus briquetter to do that, though. Tremendous energy there, but ash content I have no clue… But a point I’d like to make here. When I first got bitten by the bug I was starry-eyed just thinking that ANY bio-mass could be gasified. Well, that is somewhat true, somewhat. But after years of experimenting with this I’ve found that each feedstock in it’s final processed form is a unique critter, and that the gasifier will have to be designed to handle each and every quirk of the particular feedstock. I do not believe in a “multi-fuel” gasifier, allowing that the stratifieds probably come closest.
If you wish to pursue the holy grail of this industry, start working on MSW. Downdrafts seem to be the cleanest in terms of emissions (scale becomes an issue here), but the combustion rates of the “who knows what” in the mixture will vary greatly, and you will find some that make it to the grate untouched after all the more easily combusted have gone on through. Clogging time. This has to be addressed. And then comes your emissions, what you do with pollutants filtered out, etc. etc. Big brother be watching you…
" A friend of mine is doing a multimillion dollar bio-fuels plant with a gasifier as one small part of the overall system. His words, “I ain’t got it in my budget to pay someone to babysit this damn thing.” "
We have a saying on the DOW site . 25% machine and 75% operator.
I have had people to ask if I could guarantee the design to work? Yes if I am there to operate it.
Hi Patrick,
Brand name Holzmag, redesigned by me, ( hydraulics and controls)
Holzmag went broke after the crisis started in 2008. I delivered 4 or 5 in the states in 2008.
Clients, Louisiana Pacific in Ca also, proctor and gamble, georgia pacific, have more printing plants but cant remember the name.
Briquete was 60mm diameter, lenght adjustable, pressure up to 30 tonnes, modifiable.
I can make you small sketches or wathever info you want about briquetting…
The best size, i was developing, for gasifiers , briquettes of 25 mm, density a little more then 1,1 kg per liter.
April,
You are 100% correct in your statements
Pine needles and cones i tested at quad graphics. Never seen better briquettes…
Saddly i never had a change to test those briquettes in a gasifyer myself. Only in france for a cognac company, but that was special.
Pine wood, makes perfect hockey puck like, briquettes.
So does paper dust…
For the same reasons you have mentioned, i want to go ahead with charcoal…
For the long run its the far most convieniant way
Wayne, what would you advise as briquette sizing for your gasifier ?
And you are dead on with that saying, nothing can beat a good operator…
Wayne,
That is a very good answer. Someone has to be around in close proximity that knows the beast. I see no way around it, no matter what the suits and ties wish and hope. First thing we offer guests here is a jar of carbon soot to wipe on their face. Really, no kidding. Most refuse, but a few brave ones…
On my size gasifier I think two and three inch material works best for fuel. Some have been in the hockey puck sizes also.
I have found that any pelletized fuels left in the hopper after shut down will turn to mush from the high humidity and steam. Picture below shows cubes breaking down in storage.
Patrick,
Was just thinking that if you have a ton a day of wet sawdust then you have a half ton a day of fuel. More or less half the weight of that sawdust is going to evaporate out.
Our briquetter is a Biomass Briquette Systems LLC, model # BP-100. You should be able to pull their page up and get all the details.
Grate design would have to be critical. If you have a gasifier that continually clogs up with your feedstock you have an expensive pile of metal. Max from Europe side of the pond has a lot of excellent info on grates.
Problem with moist fuels is that the heat needed for pyrolysis of the gases would be sucked up into making steam, and that is substantial enough to prevent gas production.
Hi April
I have come to the conclusion that I will have to dry /condition the sawdust to run it in a gasifier.
If you look on my other thread -Woodgas in South Africa, you can see the youtube links of my system running and my experiment I tried yesterday of sawdust and wood chunks, only to land up with a constipated fire tube.
The sawdust defiantly had lots of power but blocked the tube.
Thanks
Patrick
Looking forward to seeing your photos and video. Sounds like you have been gasifying for some years.
Patrick,
Being newbie here I am not familiar with the web page yet and couldn’t find your woodgas in south Africa thread. Maybe you could just post the youtube link?
The small one uses 7,5 KWh with 250 Bar max on a 125mm piston or even a 140mm piston = between 30 Tonnes and 38 Tonnes pressure on the briquette.
= between 1,2 and 1,35 tonnes per cm2
short briquettes are more dense, the dryer material gives the better briquettes with less effort.( lignin seals the cellular pores )
The resin from pine wood, needles, cones, does a wunderfull job for briquetting.
@ Patrick,
You can actually look into the 3D model, and if interesting ask for a local manufacturer.
@Wayne,
As for as my knowledge reaches…
The denser the briquettes the more surface is needed to compensate the burning rate ( depth )
Some claims are that it goes proportional.
Would it be interesting for you to test with paperdust briquettes ?
I still have contacts in the states and it could be good, free fuel
Accounting said the premium membership was in the works. Guess I’ll have to wait 'til it all goes through.
Briquettes are densified fuel. One of our sawdust briquettes is 1 1/2 the weight per volume as wood chunks. So if you add the same volume it will take longer under the same gas production rate to burn it out.
Hi April
Sorry I did not know you were not a premium member.
Here is a link to my youtube video for the moment.
Or you just search youtube for woodgas powered sawmill.
Hope to see you as a member soon, there are a lot of great guys on this site with a wealth of Knowlege that are able and wiling to share, and from what you have posted you are the same, you have a little wood gas condensate coursing through your veins
Thanks
Patrick
