Gasifier running on MDF

General Discussion
#1

Hi everyone,

New to the forum and equally as new to wood gas. Here’s the background, I run a fitted furniture business in Ireland and we have A LOT of off cuts in MDF and melamine. A few locals burn it in a stove but the majority of it we send to landfill and the cost is increasing. I put on my thinking cap and stumbled upon wood gas. Right now I don’t even know if MDF can work but it would be incredible if I was able to run my home off our off cuts. Dream big right.

First question is does anyone have any experience in using MDF?

Second, anyone running their homes using their gasifier.

Would love to hear people’s opinions on this and looking forward to potentially making a gasifier!

Thanks guys,
Ian

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#2

Welcome Ian, this reads like a deja vu. I think this is not the first time this is asked. And I think it is quite problematic but I am not an expert.
We build dust extraction system for your shop. Sometimes briquette press is involved and a boiler. Both need a lot of extra TLC when it comes to MDF. Woodgassing is next level :grinning:. But dont let that hold you back.

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#3

This is interesting. Wayne sez you can get wood gas from a dead cat. Seems like that puts everything else on the table. It is after all wood fiber but the binders could be problematic. I have burned MDF in a wood stove with no apparent problems but I do keep my flue brushed out fairly regularly. One issue I see is sizing. Getting MDF broken down to fuel size could lead to a lot of fines which could clog things up. I think I"ll let someone else proof or disprove this question. Oh yeah. Welcome to the site Ian.

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#4

Hey guys,

Thank you both for your quick replys.

We can get the MDF to fuel size in the workshop. This won’t be an issue.

Is it possible to run a house permanently off a gasifier, assuming this works, I need to do something with the gas :joy:.

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#5

In the company where I work, people use a lot of acronyms, foreign words and learned terms, so they think they are more learned and important, but when you put it all together, the meaning becomes complete nonsense.
Sorry Lan, I don’t know what MDF is, I can only guess that it is particle board, which contains a lot of glue in addition to sawdust. In the gasifier, we need a thick layer of glowing charcoal, in which the decomposition of long tar chains of the gases into simple clean gases takes place, well, will MDF provide enough charcoal, will the glues be released evenly in the upper part of the gasifier, will there be too many oily sticky gases at the top,… It’s hard to give you any smart advice, I can only tell you to try to build a small pilot gasifier, that way you will find out if the fuel is suitable.
Don’t give up right away, persevere and work, you will find a way to use this fuel.

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#6

I like the idea of a pilot. Is there somewhere on the forum I can look to get plans for a pilot gasifier? Also, what should I be looking for in the pilot.

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#7

I would try converting it to charcoal first. Use your process for heating your shop and use the charcoal safely in a charcoal gasifier.

If you have a good process and sounds like no shortage of the fuel. Then yes you could take a home off grid full time 100%. But you will want to combine it with battery storage, Keep in mind when that engine is running its consuming fuel, its make noise and its eating away at its cycle life hours. Its only going to last so long. The key is run it as short as possible and harness as much power you can get out of it for that run.

A wood fuel system will be more problematic. It will not be nearly as stable as a charcoal unit the constant fiddling around and intervention will get old after a while. Tar will be a problem at some point and especially with this material. The dealing with constant daily maintenance where a charcoal unit only requires a servicing about once a month.

If you could build some retorts for shop heat and also hot water production it will actually be much more efficient as you are not losing as many BTU’s. Where a wood gasifeir loses 30% just in its in reaction process with very little water shift recovery.

Charcoal is also much simpler there is a huge difference in complexity between a wood fueled system versus charcoal. You need to see the full picture of both technology’s and set ups.

Ive closed that chapture in my life. If I had to resort to a wood gasifier for power, Id just get some candles instead.

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#8

Looks like MDF (medium density fiber board) is 9% Urea-formaldehyde resin. I think this fuel would be an excellent candidate for a fluidized bed reactor. Start up would be tricky, with the release of formaldehyde. I suspect the reactor would have to be started on propane and the granulated MDF added gradually bringing the final burn stage up to temp. I don’t see this fuel being very good for the type of gas producers normally discussed here. I would check with Greg Manning and Canadian Gasifier, for his opinion.

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#9

Hello Ian and welcome to the site.

As long as you keep a good deep bed of glowing charcoal you can add a certain percentage of almost any dry biomass on top. The problem is keeping the good char bed.

The fuel hopper of the gasifier can be a very wet and moist area where many fuels like wood pellets will break down and turn into a mush clogging up the machine .

If you have the fuel supply and the time I believe I would give a pilot a go .

Thanks Wayne

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#10

Hello Ian,
Most gasifiers that feed engines below 15KW use charcoal. Making good charcoal is easy, if you know how. I recommend Chuck Whitlock’s tipped barrel method. It‘s the easiest.
I was able to get an ancient Briggs generator running after looking at Koen van Looken’s Some School in Thailand thread.
The search tool on this site is a great tool. You can use it to find all the things and people I’ve talked about.
Rindert

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#11

hello ian, welcome in the forum…in this swiss video the guy after minute 6 has a large gasifier for electricity and heating, feeded with old furniture stuff, like you will do…

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#12

Several glues are used for making MDF. PVA as mentioned earlier is one. It does emit toxic fumes that can create respiratory issues. I do not know exactly -what- fumes it is creating and if the gasifier will crack them or if you run them in an engine whether that would take care of it or not, but I highly recommend not breathing any fumes from burning it. I suspect the fumes are actually the vinyl acetate as the bonds of the polymer degrade into the original monomer. The reaction is hydrolysis (ie water and heat) of the poly vinyl acetate back to vinyl acetate. vinyl acetate is extremely flammable and an explosive risk and emits toxic fumes when burned.

I didn’t look at other glues. I just got infatuated with the fact it is what Elmer’s uses and was thinking about all the slime we just threw away… lol

Apparently certain bacteria, fungus and other microscopic critters can digest PVA. So worst case scenario, is you can compost it.

I think around here the place that makes particleboard will buy MDF scrap if you have enough otherwise they don’t pay for it.

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#13

Yeah we had that wood working company next to us. Yes I have tried it, it dont work and yeah it will make you sick smelling those fumes too.

Thats why I suggested converting to charcoal and burning off those fumes in the retort

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#14

Hey Matt,

Can you tell me what didn’t work? I plan on making some tests next week and you would love to know what to expect.

Thanks

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#15

You cant crack the glues, there are many different glues as mentioned. There is the bonding glues for the partical board. But generally this board is also laminated and there are different glues for that as well.

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#16

Thanks Matt, do you mean that it is impossible to get any gas?

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#17

Oh that stuff make plenty of volital gas. Its not going to be usable unless you can get that stuff out. This tar is not any tar you want to deal with. That stuff cures like concrete, yeah there is no fixing the vavles you will mushroom the stem trying to remove it even with a ton of heat.

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#18

This was before I started charcoal gasification. So I have no idea if you can make it into engine grade charcoal or not. I would assume it will make very good charcoal as its already very dense. Make charcoal is not hard or labor intensive. The retort does the work, refine your fuels first its worth the added process. Take the easy road not the hard road.

Larger engines you can wood gas but the smaller the engine the more dificult it will become. There is point where constant intervention becomes too much for it to be viable. Even a solid system that is as easy as it can get is still a chore. Its not like filling it up with gasoline pulling the rip cord and it runs until the fuel runs out. Oh no you make the fuel, then you have to get the unit loaded up and fired up then get the engine running, get things warmed up before loading, Then all is good right? Yayyy you walk away and 5 min. later you are right back there fiddling with air mixture kicking the stupid thing trying to keep it flowing, then you tar up a valve. Off with the Head!! Then you get it back up and running only to repeat this process over and over. Sometimes you get lucky but with no fuel standardation, your success is in your hands.

Charcoal is where everyone should be starting. You dont become a brain surgen overnight. You go to college for years to get there. Learn this foundation first. I wish I could start over and start with charcoal. I wasted many years of my life chasing this and I dont care if makes people here angry. Im being realistic and pushing the right path forward.

When you can opperate a retort and learn to do this without any smoke then you have mastered the pyrolysis and distilation process. You will have to learn to use pre dried fuels and how much moisture you can get away with to get to this result. You will learn to make good charcoal that is a requirement in any gasifier. It is the heart of it. There a lot you can learn here before you build an actual wood fuel system and this knowledge to shape your project and be more successful.

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#19

Because it is small bits of wood stuck together with glue, you are going to have a hard time getting a bed of char that cracks the tars from the actual wood and still has enough gaps to let air pass through it like is normally done with the gasifier designs we typically use. So you could add it to say other actual wood, to keep the bed going, but wood is at a premium in Ireland.

Honestly, I think Matt is on the right track.

Here is one study on making char, and the study itself isn’t that important. the citations section is. (Plus it isn’t behind a paywall that you have to use sci-hub.se to try and access the paper). https://www.desirabletomorrows.org/assets/files/Conversion_of_MDF_wastes_into_a_char_wit.pdf

They reference a study that is making bio-oil, char and a gaseous product with both a screw retort and a microwave.

The char is easily usable as say biochar, and most of ireland has very poor rocky soils, add the right microbes via say compost or vermiculture, then plants/garden, etc will go boom.

If you condense off the liquid fraction, into what they are calling ‘bio-oil’, there are enough chemical companies in ireland that would buy it. One other issue is MDF contains urea-formaldehyde which a study in Brazil was saying could be used as a fertilizer. You may also be able to dewater the liquid (heat it to 105C) and use it as a diesel fuel. You probably have to dewater it before selling it to a chemical company anyway.

When briefly looked at the screw retort study, they were using 15 minute residence times, so it actually sounds like it goes very quickly and a lot faster then I would trust for just burning off the gases to sustain the reaction. Thus I would highly recommend looking at something that condenses the liquids off. Which is a closed retort, and used for making “wood vinegar”. A batch process would system is essentially a pot still. The screw is a continuous system. They used like 1mm particle size and smaller, and another study used up to 20mm in size, so it would probably need to be chipped.

The bottomline is you can get heat plus some other valuable materials out of it as well as avoid disposal costs. It very well could be worth your time. I suspect you have quite a bit of it.

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#20

Its an issue here as well. They dont want that stuff in the landfills and they charge extra to dispose of that stuff. The guy built a huge outdoor wood boiler to heat his shop with that stuff but even though he has tons of it he still has to process fire wood to burn with it otherwise it will make everyone within a miles range sick.

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