Plastic in a gasifier

Hi Chris,

I have seen where plastic can be made into Diesel by heating it in a sealed container to 400 degrees Celsius and condensing the vapour. Would adding small amounts of plastic in your gasifier be of any benefit or would it just make a sticky mess?

Gary,

Yes some amount of plastic can be added. The benefits are unclear. Check out Wayne’s test results here: http://driveonwood.com/resources/pdf-articles/auburn-university-efficiency-tests

He tested plain wood, broiler litter, plastic trash bags, and switchgrass. The other fuels were added to a wood base, not run straight.

Just had a quick look at the data, just on the distance travelled it appears to have had a better result with plastic added. Is there any major drawbacks, plastic is so common in our rubbish.

Small amounts are OK. Too much and you’ll get a sticky mess, plus it doesn’t make very good charcoal. But yes, you can mix in a little with your wood. Wayne will have to comment on how the truck performed during the plastic test.

In Wisconsin it is against the law to BURN any plastics but there is so specific reference to gasifying plastics which is what we would be doing if we threw some in the hopper. The issue is that PVC type plastics will produce nasties like dioxin and the such. Some of the guys in finland would throw a quart plastic bottle with waste oil in the top their hopper before their commute which would obviously melt and run the oil into the wood chunks. Expect about 4 times the power while that oil is being distilled but plan your trip so you use it all up. I personally haven’t run any plastic but I have dumped waste oil in my hopper … It’s kick ars … ML

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Mike, Would like to hear more about mixing oil with wood. Does the oil convert to usable gas or just accelerate the wood burning process?

Would be easy to add a external container for oil with a valve to control when it is added. If it produces significant extra power would good to be able to turn it on as needed.

Peter I am guessing but there is signification energy locked up in the oil so would add power rather than just causing extra wood burning. After all oil comes from plant material also that has been locked up under ground for millions of years and changed it’s chemical structure without oxidizing.

Hi there,

I remembered a TV report that was aired a couple years ago. I looked it up and found it was in 2009. A guy added a “reactor” to his small Volkswagen Lupo, in which he put plastic trash. Then it was gasified in this reactor chamber and fed to the intake manifold. I assume the outer wall of that reactor is heated by the exhaust gases and in the inner chamber the plastic gets gasified. They say it gives significantly more power, yet boosting the mileage by 30 percent.

The media guys called it “flux capacitor” - I know we had BTTF-references in other posts…

I have added the links (German though…):

Best regards,

Sam

Hey fellows
I have only ran slight amounts of used motor oil.
Ran a LOTS of dripping pitch wood. Both very powerful with all of the extra HC volatiles that can be converted to woodgas fuel components.
PeterC the actual wood will not convert until these easier dense vaporizable HC’s are all used up. There-in is the problem. Before the char core of the new woodfuel could be released available for char bed resupplying the pre-set-up char bed would be consumed converting the oil or wood pitch HC chains.
Process would always crash running out of reduction bed wood char. THEN output gas would go too unconverted CO2 and water vapor high and the engine lose power, combustable fuel starve and die.

I would NEVER subject my neighbors to ever gasifing or burning any plastics. Just too many nasties in the colorants and stablizers with metals and such. Good way to give clean, GREEN, Woodgasification a bad name even being seen doing this.
I have walked away from these systems and withdrawn any support.
A HIGH TEMP OXIDIZATION system can covert any HC combos including Nerve Gases. Needs real forced air for the burner and specific burner designing and specific designed good down stream scrubbers though for the nasties residues from the chlorines and metals molecules.
Gasification for motor fuels as such is NOT an oxidization process.
It is an intended oxegen starved process to be able to procduce the then energy potential motor fuel gases.

Regards
Steve Unruh

Hello all,

My thinking pretty much coincides with my buddy Mr. Steve. I think one can run about 10% plastics with no problem but I don’t like to. If the plastic is in my way such as plastic hay twine, empty oil containers, etc I will chunk them in the gasifier. But in my situation I have a lot of wood that is going to waste if I don’t use it so I don’t go to any length gathering plastic for the gasifier.

The test we did at Auburn I think I let a large concentration of plastic get in the fire tube at once. After the test I inspected the air cleaner housing and found there was a strange build up fluffy black material that I had never seen before and haven’t seen since.

Wayne, Max commented on there being additional soot when adding oil to the wood and I would assume the same for plastic. I suppose if you quench the fire in the least, it will be tough to fully crack the stuff. ML

OK, newbie weighing in with an opinion.

While a properly executed gasifier can cope with a small amount of plastic within it, I personally do not see it as an idea I want to get into. The whole idea of “driving on wood” is tainted when you start putting in the waste products from the petrochemical industry. However, it has intrigued me so I have researched it further. Back to that in a bit…

On a side note this was battered around at work a while ago. Stick with it, I am going somewhere with it. Having a 50cc Peugeot 2T moped it is capable of mixing its own 2T oil with the fuel. It has a very small oil pump which drip feeds the carburettor with 2T oil. The thought which we hammered around was to use this pump to “drip feed” black diesel (waste engine oil) into the fuel line of a diesel vehicle. I know there are problems with implementing such a thing and we really thrashed those points to death. Anyway, the point of it was to use waste engine oil to nudge up fuel economy while being quite discrete about the whole deal. Mainly because using waste engine oil as fuel on a UK road will get you in a whole vat of trouble, so feeding it in right behind the fuel pump would need a skilled mechanic operating on a tip off to even spot it. After reading about Mr Gilmores excellent Simple Fire the thought of a moped oiler was rekindled. Having a vertical inlet would allow waste oil, or even a more environmentally friendly vegetable oil to be drip fed right into the reaction zone. A theory that I am willing to try if I can get to build a most excellent Simple Fire. I’m sure that it could be adapted to drip oil into the reaction zone of a downdraught gasifier after a little thought on implementation.

Anyway, back to the plastics issue. After watching “Back to ze Future” (sorry to any of my Germanic European cousins, I couldn’t help the pun) and seeing a Lupo being substituted on its fuel by a plastic pyrolysis gizmo I searched further and found a PDF from an Indian intellectual heavyweight who did the research on running a diesel on pyrolised plastic. Its not that long but contains some real raw data. There is no meaty info on the setup so no way of copying what they used but it is inspirational to read. If your interested the link is below (hope it works). I have a PDF copy of it but can’t fathom out how to get it on forum. If you want a copy then email me. It may help to watch a few episodes of The Big Bang Theory first to get you used to the level of intellect in its content!

www.academicjournals.org/jptaf/PDF/.../Naima%20and%20Liazid.pdf

Hi Neil,

The link above is not working for me.

First off to add oil to the Diesel why not simply add it to the fuel tank with the Diesel. I know many truckies here do this when they do an oil change, not sure how long the fuel filters last doing this.

Is the plastic pyrolisation you mention the process where the plastic is cracked at 400 degrees and condensed. There is a lot of information about this on the net already. It does not work with all types of plastic, I should have considered the nasty chemicals that could be produced. There are others who are doing a similar thing with tyres, apparently that is a dirty process.

Adding oil to a wood gasifier may work better if the oil is preheated by placing a coil of copper tube around the cyclone.

I was wondering about this as well, only my thoughts lean more towards being able to utilize wood gas in a Fischer Tropsch reaction. After doing research on this subject it appears that wood gas is not suitable for this reaction because it does not have enough HC or C and to much N. So I researched using pure oxygen/steam combinations to increase the CO, CO2, H2 concentrations. It does. But still not sufficient for GTL. Hence the thought to add plastics to the mix, which should provide the additional HC I would think. Then perhaps it would be possible to try GTL with the ratios being closer to ideal? Just thinking here. I know it’s not as “green” but we have plenty of plastics that need something done with them. I know I’m going to start experimenting with Plastic to Liquids, make some diesel, why not.

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I think the best way to deal with waste plastic is a wood gasification boiler. The secondary air in one of those boilers can be set up to burn the fully burn the plastic down clean. I am sure there are still some waste products you don’t really want but if the elements are there in the raw products they will be in the byproducts regardless of how you process it. I suspect there is alot of sulfur in plastic. My guess is the sulfur that was in diesel is being pushed into other products to make low sulfur diesel. It is pretty typical of big business manufacturing to try and just tweak the process so they don’t end up with an additional waste product they have to deal with. Atleast that was my experience in industry.

I have wondered about processing waste plastics into something useful. If it could be done you could setup a floating refinery in the ocean and have all the raw materials you could ever want. I read an article a few years back about how there is a still spot on the middle of the Pacific Ocean where plastic collects and that there is a mass something on the order of the size of Texas of floating plastic and how it kills wildlife. That got me thinking of all those “Free” hydrocarbons that could be collect by just skimming the water surface.

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I like the downdraft gasification boiler idea for recycling plastics. The high operating temperature and steady state operation with excess oxygen should make for a good incineration environment. I try to reduce my waste the most possible, but the plastic wrap and packaging is a real problem is would like like to solve for myself.

Paper and cardboard incidentally, are perfect candidates for recycling in a stove, generally it costs far more energy to reprocess them than starting with pulp logs. Greenwashing is a good business…

Regarding the plastic gyre in the Pacific, my understanding is that it’s extremely diffuse, and won’t be practically collected, at least with any commercial return. If it was collected, it would be of every type making reuse impossible, apart from uv degradation, etc. People don’t realize that the majority of plastic contamination is actually lint from clothes washing, and now plastic micro beads from toothpaste, etc. Given that lint is the main problem, our rivers and lakes will be very heavily contaminated. The only way to fix that is use organic fibers for clothing.

Regards,

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I was thinking if you where burning it the differ types of plastic wouldn’t really matter you would just need to keep a hot fire. But it probably isn’t practical just made me think about the scale of the waste problem.

There is a Russian design for a wood gasification boiler that goes straight to steam to run turbines and provide heating in one of their major cities. I read about it years ago they burn tires in it and claimed they burn clean.
We have a trash to energy plant here. I think it is a great idea but that the trash stream needs to be controlled so you know what is going in to avoid toxic ash.

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There’s actually significant commercial effort in biomass heating systems, many could be used to burn some quantity of plastics or other wastes. It’s my understanding that soviet Russia largely focused on district heating systems and piping the heat to homes. Makes overall economic sense for a state.

Plastics in the US labled 1-4 i believe.(#3 is pvc so double check, and IIRC the EU uses different numbers.) Are not chlorinated, and will not created all the dioxins. The plastics labled 5-13 are not okay which includes things like bottle caps and plastic bags. Since most people just burned all plastic we ended up banning the burning of all plastics because of the dioxin emissions which were causing a large number of issues.

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https://www.researchgate.net/publication/281064326_CONVERSION_OF_PLASTIC_WASTES_INTO_LIQUID_FUELS_-_A_REVIEW

Actually there isn’t much sulfur in the plastics. At least not from the research I have done. There is actually research regarding putting elemental sulfur into the plastic up to 30% by weight. So what you stated appears to be true. Try to get rid of the sulfur somehow. I like the idea of plastic to liquids because it’s not very environmental damaging. It’s self contained. And a simple process. One could take it even further, and fractionally distill the liquid and produce other liquid products. Typical of any petroleum distillation. This process is not difficult to achieve in small scale either. The other plus, is the amount of return. You get almost pound for pound return. So a pretty efficient process. I’m I’m process of gathering all the components and I plan on building a completely self contained demo unit for public display and scrutiny. I happen to live in an area that people extremely favor recycling of all kinds. I build ultra energy efficient homes, and strive for net zero or net positive outcomes. I’m trying to think of a way to incorporate the use of wastes back into the home as an energy source. I hit the local junk yard regularly, and am buying the necessary components for nearly nothing.

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