August 24th, 2006
Can you burn plastics? This is a very old question that has not really been answered. Some people think that burning plastics in wood stoves, furnaces, or in open fires is better than burying plastics in land fills. But this practice produces a lot of pollution and health hazards that cannot be ignored.
Let's break the problem down to size. Burning garbage produces unpredictable results when burned together. This is because garbage contains so many components that when burned, simply changes chemical form. The resulting pollutants are therefore always unknown. When you burn plastics with paper and other materials, the chemicals on them may be released unto the atmosphere or left on the ground. These will find its way into the biological systems of plants and animals and ultimately deposited into human cells and tissues. From there it may cause anything from simple allergies to more formidable conditions like Cancer.
One of the most dangerous pollutants that is produced as a result of garbage being burned together is a highly toxic chemical called Dioxin. According to Wood Heat, Dioxin does not decompose and builds up in tissues of animals and humans, and can be found in fat cells of cows and humans. The World Health Organization said
"Once dioxins have entered the environment or body, they are there to stay due to their uncanny ability to dissolve in fats and to their rock-solid chemical stability."
In incinerators, Dioxins can be destroyed but in open fires, it will be produced. To stop the incidence of toxins being produced, garbage must be segregated prior to burning.
Which leads me back to our original question, after segregating plastics from the other components of garbage (which must be recycled when applicable),can we burn them?
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.
August 24th, 2006 at 10:21 pm
You will never convince the California environmental lobbyists that plastics can be safely combusted. Gasification, by contrast, is much cleaner than regulations require and certainly cleaner than the status quo, landfills.
Gasification is a completely clean way to “burn” plastics – segregated or mixed. It differs from the combustion or incineration you are talking about. Combustion releases a witches brew of toxic particulae matter into the atmosphere.
During gasification the feedstock plastic is reduced from solids under high heat in a near vacuum closed environment. The gases are captured and scrubbed to remove trace elements. The bulk of the remaining “syngas” is composed of CO and H2 which can be combusted directly (like natural gas), used to create steam to generate electricity, or fermented into ethanol using catalysts or bacteria.
Los Angeles is applying this technology in their 20-year plan (called RENEW L.A.) to replace landfills with biorefineries.
August 24th, 2006 at 10:24 pm
You will never convince the California environmental lobbyists that plastics can be safely combusted. Gasification, by contrast, is much cleaner than regulations require and certainly cleaner than the status quo – landfills.
Gasification is a completely clean way to “burn” plastics – segregated or mixed. It differs from the combustion or incineration you are talking about. Combustion releases a witches brew of toxic particulate matter into the atmosphere.
During gasification the feedstock plastic is reduced from solids under high heat in a closed environment vacuum. The gases are captured and scrubbed to remove trace elements that can be safely recycled. The bulk of the remaining “syngas” is composed of CO and H2 which can be combusted directly (like natural gas), used to create steam to generate electricity, or fermented into ethanol using catalysts or bacteria.
Los Angeles is applying this technology in their 20-year plan (called RENEW L.A.) to replace landfills with biorefineries.
September 11th, 2006 at 10:21 pm
Hi Scott, thanks for dropping by! The information came from fuel engineers and some experts in the field that have burnt plastic, albeit on a small scale, in some areas in India. For large scale operations (such as those you envision for California), there will be some legal and technical constraints (legal because the law doesnt allow you to and technical because of the sheer volume of plastics involved).
However I agree wiht you that gasification could potentially be more appropriate in this case, I have just not encountered a gasifier of that scale (but i wouldnt mind hearing from you where this could be found and blogging about it). I have seen some biomass gasifiers and they work well. Plastics, not yet, so please tell me where they are.
Thanks scott! Best regards!
November 7th, 2008 at 10:55 pm
Dear Reden,
I am a Degree Student of Environmental Science and therefore it concerns me so much,the issue you have chosen.I am really interested to know what analyses have been actually carried out and what are the researches that actually support burning plastic is not harmful. I have heard that only PVC when burnt emits Dioxin and I would want to know the test results and about the countries which have accepted or are convinced that burning plastic is not harmful.I would be happy if you could provide me with the scientific revealations because I intend to make plastic briquettes so I would better know these things.
January 2nd, 2009 at 4:47 am
Hey Scott if could guide me about the permissible standards of chlorine in Municipal Solid Waste.Ihave also learnt that dioxins and furans gets completely destroyed when incinerated at temp. more than 1100 deg.C.Upto what extent it is true? And i agree technolgies like gasification are clean but are these tech. not very expensive?
Thanx scott!
With Regards.
January 2nd, 2009 at 5:02 am
Hey Scott! could you please guide me about the permissible limit of chlorine allowed in Municipal Solid Waste.I have also learnt that dioxins gets completely destroyed when incinerated at 1000+ temp.How far it is true.I agree with you that gasification techniques are cleaner but are these tech. not very expensive?
December 12th, 2009 at 10:45 pm
sir i am diploma student i am doing a project that is power generation from plastics i have a doubtful question that is 1) which gas is delivered from the polyethelene plastics.
2)how to change that gas into untoxic gas
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