Carpet, Wood Chips, Asphalt Shingles, coal, rubber tires ect..... expirements

TMonter said:

If you start with fuel that only has carbon, hydrogen, and oxygen in it and it has time and temperature enough to fully react, I think you only get CO2 and water. I completely agree that fuels with heavy metals, chlorine, sulfur, and other noxious chemicals should not be burned. That includes rubber, and I’ve said that from my very first post.

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Do you have the 1.5 second residence time at temperature needed to burn the compounds formed off? That is another problem with small boilers.

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That's perhaps the critical question. Where my chemistry falls apart is in figuring out the reaction chain for a complex hydrocarbon like PET. I assume that the coal bed in the primary chamber acts as a cracking tower, so that a good deal of the sequence happens before you get to the flame front. Is there anything that requires a longer or more complex intermediate stage than wood does? Are there any nasty intermediate hydrocarbon compounds that don't break down easily in the combustion environment?

I would guess that there's a good deal less than 1.5 seconds between the end of the flame zone and the heat exchanger pipes that serve to drop the gas below reaction temperature. However, there's a good deal of time spent at elevated temperatures in the primary chamber.

Seyiwmz said:

Sometimes the "Conservative" approach needs to be ditched. What if Christopher Columbus, Chuck Yeager, John Glenn, or Ozzy Ozborne took that approach. Were would we be then........ I probably emit more toxins in the air from my commute to work than by throwing in a piece of carpet now and then. I make it worse when I leave the parking lot doing a smoky burnout until the tires almost melt off my rims. Maybe not quite that much. But the smoky burnout will fade into the plume coming from my workplaces smokestack. They only burn 600 tons of coal a day.

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In all fairness to Web, I wouldn't want to burn anything that adds to the problem, regardless of what my workplace does. I spent the extra bucks for a gasifier in part to have cleaner air in the neighborhood.

I am interested in what items could be burned cleanly, though. I agree about pushing the envelope, but the examples that you cited were backed up by instrumentation, and with the exception of Ozzy, by hard science. I thought that you asked a good question.

Based on my understanding, there are things that you probably shouldn't burn, at least in any meaningful quantities. Some things might be able to be burned safely. Shingles are a good question. How many shingles could you burn without exceeding the emissions of a paving machine, for example? What's in a shingle, anyway?

If you created a synthetic material that was chemically identical to wood, would you be able to burn it? I'll bet that there are people who would be up in arms about all of the chemicals that you'd be releasing into the air.

We'll see if people with actual knowledge help out. Seems like there are a few here.

OK, so a combustion engineer who works in the field know nothing about it? neither do the hundreds of easily findable sources on google which say, for instance:

"PBDEs, to take just one example, are used in many products, including computers, carpeting, and paint. As for phthalates, we deploy about a billion pounds of them a year worldwide despite the fact that California recently listed them as a chemical known to be toxic to our reproductive systems. Used to make plastic soft and pliable, phthalates leach easily from millions of products—packaged food, cosmetics, varnishes, the coatings of timed-release pharmaceuticals—into our blood, urine, saliva, seminal fluid, breast milk, and amniotic fluid. In food containers and some plastic bottles, phthalates are now found with another compound called bisphenol A (BPA), which scientists are discovering can wreak stunning havoc in the body. We produce 6 billion pounds of that each year, and it shows: BPA has been found in nearly every human who has been tested in the United States. We're eating these plasticizing additives, drinking them, breathing them, and absorbing them through our skin every single day."

An yet, folks are willing to accept "experiment" that are scientific which think that no smoke means no dioxins! These are generally classified as "odorless" chemcials!
Meanwhile, every human in our country has this chit in our tissues!

C'mon, now, use just a little bit of common sense. No one is going to really do a study of how well your residential boilers incinerate poisons! The facts already exist. So the onus if on the folks who say "these chemicals are safe" to prove it, not on "proven science" to dispute these (silly) notions.

Some related info - :
http://www.dnr.state.wi.us/environmentprotect/ob/agplasticseffects.html
http://www.dnr.state.wi.us/environmentprotect/ob/dioxinfaq.htm
http://dhfs.wisconsin.gov/eh/HlthHaz/fs/WoodBrn.htm

http://www.woodheat.org/environment/garbage.htm
http://www.epa.gov/woodstoves/healthier.html
http://www.swcleanair.org/properuse.html

So my suggestion to those who want to burn crap is to contact the manufacturer of the boilers and see if they have certified test results of the chemical output from said boilers from burning that crap. Otherwise, burn wood.

My opinion (one persons), anyway!

Tmonter had some great information, and I haven't argued with any of it. He raised some questions that are relevant to the discussion. He also reinforced my point that items which contain chemicals other than carbon and hydrogen present serious risks.

I've consistently pointed out why some items should never be burned, based on my knowledge. The original poster seems quite prepared to accept this information, hopefully improving on the original situation.

Where I'm not sure about the results of burning in a gasification environment, I've tried to ask questions to learn. The most common plastics contain nothing except carbon, hydrogen, and oxygen. No chlorinated dioxins. No PBDE. Maybe they emit toxic fumes when burned in a gasifier type environment - maybe not. I'd love to be enlightened. I don't think there are a lot of toxic chemicals that you can make from those elements that will survive a 2000 degree oxygen rich fire, but I'm willing to learn.

Continuing to refer to links about indiscriminate burning of rubbish and tires in conventional woodstoves, barrels, or OWBs adds nothing to the net knowledge on this topic. That's not what this thread was ever about.

I'm quite sure that the manufacturer's lawyers would not allow them to answer in a meaningful way for the purpose of this discussion.

I'm sorry if asking these questions makes you uncomfortable.

It's not to say that you can't burn some of the things mentioned here but more of should you burn them.

Asphalt shingles, plastics, and carpet remnants all have nasty chemicals and binders in them that would not only void the warranty of the boiler burning them, but are also unlikely to completely be destroyed in the limited residence time/temperature of a small home boiler.

I've done several TDF/RDF/Autofluff projects and none of them has been under 100MMBtu/hr, mainly because you cannot maintain good combustion characteristics below that. Most projects of this type also require SO2 scrubbing capabilities.

Craig's right, you really should only be burning biomass in your wood boiler, and not engineered products (wood or otherwise).

In fact one of the local guys here actually takes leaves and cubes them into a biobrick form and burns them in his boiler.

This was a very interesting thread to read. Don't have any knowlage about chemical engineering or thermo engineering. I do know that I love burning wood there is a certain romance about going into the woods pulling out tree's processing them and using them to keep your family safe and warm. Its a natural process tree's storing energy you extracting said energy. I'm all about trying to find new and inproved ways of doing things, but I don't just buring things to see if they will burn is the way to go. I don't see it any better to put the solid waste in the air then to put it in the land fill. If that is the concern I think that the most reasonable option is to recycle. I guess I don't think I personally could find satisfaction in burning any of the tires, shingles, carpet etc. just my opinion. besides my pocket book is not deep enough to "experiment" with a gasifier.

A little research turned up two sites that specifically discuss burning plastic. Links and excerpts from each are shown below.

http://www.newton.dep.anl.gov/askasci/chem00/chem00922.htm

"Question - What are the hazardous products of burning Polyethylene
Teraphthalate or PET; high density polyethylene, HPPE; low density
polyethylene, LDPE; polyproplene, PP?

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Question 1: All of the polymers you list are hydrocarbons so other than
the usual hazards of the combustion of hydrocarbons -- CO2, CO, carbon
particles -- there are no unusual hazards.
Additional hazards might be present from components used in the manufacture
of plastic parts however. I am thinking of pigments, and other additives."

http://www.ifenergy.com/50226711/can_you_burn_plastics.php

" The answer is yes, several types of plastics can be burned. Toxins come from "Halogenated Plastics", those that are made from chlorine or fluorine, which clearly should not be burned. On the other hand, Polyethylene which is a common plastic and is not made from these chemicals can be burned. Polyethylene has the same heating value as oil and can be mixed with other fuel types easily (grounded and mixed thoroughly).

But why should we burn polyethylene, when it burns easily and produces black smoke and soot? Some researchers in India are looking at binding briquettes using polyethylene. Mixed with well ground agro-residue for use in high temperature combustion systems, polyethylene plastic can be used as a major component for char briquettes.

The most important reason for burning plastics this way is that when collected, sorted, and used as fuel, the amount of plastics used by one household on a daily basis is almost equal to the amount of plastics reused as fuel, thus solving an energy and a waste management concern."

An interesting discussion! Perhaps it would be a good thing if our garbage dumps were replaced with state of the art incinerators that would generate power, with all necessary emissions controls. We could stop wasting fuel to separately pick up recyclables such as paper and plastic, and stop leaching nasty stuff from landfills into our ground water.
As an aside, because something is natural doesn't make it good. I burnt a piece of nice pitchy wood in my outdoor burner last summer and was a little shocked to see a thick cloud of black smoke coming out the chimney. Cautious sniffing revealed a foul stench like that of burning motor oil.

Easy to agree that we can talk about controversial things -- but it is irrational to the point of stupidity to claim you have the right to do something just because you can. One who experiments with potentially dangerous stuff that can harm others when the ability exists to reasonably determine in advance whether that harm is likely to result, and then proceeding without making that determination, is surely irresponsible and may be lunacy. Let's be greedy about preserving and protecting the only environment we have rather than be greedy about one more dollar in our pocket.

I hadn't seen in this conversation whether some of the these manmade products have high BTU/LB ratios. In other words does someone have a large supply of plastics that burn very hot. Is there some specific product or material that sticks out as a good fuel.

Or, are we just kicking this idea around.

There could be a liability issue burning these materials also. A few years ago a neighbor a mile down wind from me tore the asbestos shingles off his house and resided with vinyl. For about 2 months during the summer when everyone had their windows open and kids playing outside he burned a wheelbarrow load every night after work on a burn pile. I have athsma and it killed me to go by on the way home from work. Started going a couple miles out of my way to not pass his house. I called him to let him know what he was burning and got a not so pleasant response. Called the neighbors with kids to let them know what he was burning and they did nothing . If my house had been downwind I would have had every environmental dept. under the sun knocking on his door

You are quite lucky to have such a considerate neighbor. I have never seen anyone who would admit to burning asbestos. I am surprised you didn't throw him to the local authorities.

In any-case, since the time of the Greek's they knew asbestos was dangerous to be in close contact with humans.

I hope in earnest that we are not going to be likening this discussion to the burning of asbestos.
I don't think that is fair or accurate.
Ironically, asbestos is a natural material, we have only been talking about man-made stuff.

There will always be a liability issue. IME you can sue anyone for anything, but our goal in this line of discussion was is it safe, practical, even reasonable.

I agree with you it wouldn't be politically correct. I would be viewed as you put it like burning asbestos- even though there is no relationship.

While were being PC I would like to say I don't condone killing of neighbours with any chemical compounds natural or synthetic.

Let's remember asbestos doesn't burn. Asbestos shingles are not made of 100% asbestos, only 10% max, they call it ACM asbestos containing material. Asbestos was added to shingle material to give it toughness, and fire resistance. All those noxious fumes came from the resins holding the stuff together. IMO the poor bastard kept all the asbestos to himself and his own airspace.

Burning asbestos . . .what a novel idea . . .

Anyway, just curious how many of you bitchin about burnin' plastic also smoke tobacco . . . :smirk:

eeeeeewwwww.........that was low...........

Of course your correct, but Indiana state forbids it being burned, because they are worried about the fibers being moved with the hot air currents-- not smoke inhalation. I think they included it in flooring too??? right??

Yes it was also in flooring to increase wear resistance.

I've breathed my share, fixing up old houses/heating systems. It takes at least 20 years to find out if you're screwed. My dad worked on ships and in power plants for many decades and is still cutting wood for a living, so I'm not overly concerned about genetic dispositions, but it does seem to hit some people and not others. Knock on wood, or whatever non-asbestos-impregnated product you have handy. Quitting the cigarettes is a big factor, I hear.

Here in Maine, certain people have burned these things in their OWB. Then certain people got bent out of shape and started banning them in towns and the state legislature has had a couple of bills on to curb them somehow. It only takes one bad apple to start a witch hunt. This is MAINE!! er have burned wood here to stay warm for ages, now certain people want to ban them, even though a large majority of people use them correctly. I have not burned anything but wood, and yed I have burned wood with nails in it but nothing like tires. I do not hink its a great idea, but what do I know.

My cousin in VA had a bumper sticker on her car once, it said "Ignore your rights, and they'll go away", how true. Over here on Long Island, not many people have wood burners, but the few who have OWBs have to remove them if they are not more than 200' away from school, nursing facility, or park by the year 2010. Hell, they're even trying to ban the sale of incandescent lamps by 2012. Like I said, the land of no. It's like the people that move next to a racetrack or airport, then try and sometimes succeed in getting rid of the "nuisance". It's true that there are some people who don't really care about anyone else's life and will burn anything that will burn, but usually they are few. All it takes is one person that doesn't know when to quit, and has plenty of time o their hands to be a thorn in a legislator's side to push they're self serving will into law..............just my 2 cents.

Not too many years ago, you hauled your trash up to the town dump and some local drunk would bulldoze it into piles and burn it in a smoldering fire that never went out. So it's not like somebody burning garbage in an OWB is suddenly unleashing heretofore unseen toxins into the environment. Now, around here, they load the trash into semi trailers and truck it down to a landfill in Pennsylvania where presumably it's put into longterm storage for some future generation to worry about.

I think it would be good to find a way to handle our waste locally and responsibly, but I agree that burning it in our boilers is probably not the best approach. All our wet, organic garbage goes into our compost bins. That's a minor drop in the bucket, but aside from satisfying my need for good, organic fertilizer, why should somebody in Pennsylvania have to deal with waste that I can easily dispose of in my backyard?

Maybe if enough people get woodburners, somebody can analyze and code different packaging products according to their ability to be safely burned--kind of like the recycling codes they have now. If I could safely and responsibly recover some heat value from some of the things I now toss into the trash, it would be a win-win as far as I can see.

When it comes to cardboard, and paper, I usually burn those, maybe 50% of the time, the remaining 50% gets recycled. Who knows, I'll probably be fined in the future because I'm adding to my carbon footprint.

I wasnt talking about paper and cardboard in OWB, I burn all those in mine have a HUGE composter in the garden, I do not consider paper products trash, I consider them fuel. (Xmas time was great, all that cardboard from presents, it last half a day)