4 ms·

Why don't we just burn all these plastics in waste2energy plants? Even with perfect recycling, the limitation seems to be on collection and separation.

ezconnect 4y ago
That's the solution of the Japanese, and they are very efficient on it, burn them and turn them to electricity and the extra waste get used as land fills.
- kzrdude 4y ago
  Also Sweden burns a lot of waste (landfills for household waste are entirely obsolete). Rest heat is used for domestic heating.
shagie 4y ago
Combustion products. https://en.wikipedia.org/wiki/Polystyrene#Incineration https://en.wikipedia.org/wiki/Polystyrene#Incineration > If polystyrene is properly incinerated at high temperatures (up to 1000 °C) and with plenty of air (14 m3/kg), the chemicals generated are water, carbon dioxide, and possibly small amounts of residual halogen-compounds from flame-retardants. > When polystyrene was burned at temperatures of 800–900 °C (the typical range of a modern incinerator), the products of combustion consisted of "a complex mixture of polycyclic aromatic hydrocarbons (PAHs) from alkyl benzenes to benzoperylene. Over 90 different compounds were identified in combustion effluents from polystyrene." The American National Bureau of Standards Center for Fire Research found 57 chemical by-products released during the combustion of expanded polystyrene (EPS) foam. Yes, you can burn it... but the things you make out of it unless you are really trying to burn it (and then its a burn it to dispose of it rather than get energy from it) leave some less than desirable compounds.
- orangepurple 4y ago
  Yeah there may be awful byproducts at burn temperatures required for optimal power generation but if they can be captured/condensed/solidified they can be collected as solid waste and buried.
  - KennyBlanken 4y ago
    Yeah, let's just bury those toxic cancer-causing compounds! What could possibly go wrong? looks over at the 1300 superfund sites around the nation
  - shagie 4y ago
    The energy to condense out and capture the undesirable products becomes comparable to the energy capture it. Japan's approach isn't because they need energy but rather that they are trying to minimize landfill (as its an island and space is at a premium). The resulting products are carcinogenic toxic waste - which comes with additional challenges for disposal. In the US, it is likely more desirable to bury the inert polystyrene rather than trying to deal with the PAHs ( https://en.wikipedia.org/wiki/Polycyclic_aromatic_hydrocarbon https://en.wikipedia.org/wiki/Polycyclic_aromatic_hydrocarbo... ) and other byproducts. The article is describing a process where UV light and a catalyst break down/transform polystyrene into diphenylmethane ( https://en.wikipedia.org/wiki/Diphenylmethane https://en.wikipedia.org/wiki/Diphenylmethane ) which is a feed stock for many other (useful) processes. The paper referenced in the article is Cascade degradation and upcycling of polystyrene waste to high-value chemicals https://www.pnas.org/doi/10.1073/pnas.2203346119 https://www.pnas.org/doi/10.1073/pnas.2203346119
- noselasd 4y ago
  Is there currently a bottleneck that prevents burning it at 1000°C and getting energy out of it ? Sounds like business opportunities ! Make an practical incinerator ?
loudmax 4y ago
Wouldn't it be better to bury plastic in landfills? Keep the stuff out of the ocean, but I don't understand the harm in landfills. Put that carbon back in the ground where it came from.

ezconnect 4y ago

That's the solution of the Japanese, and they are very efficient on it, burn them and turn them to electricity and the extra waste get used as land fills.

kzrdude 4y ago
Also Sweden burns a lot of waste (landfills for household waste are entirely obsolete). Rest heat is used for domestic heating.

shagie 4y ago

Combustion products. https://en.wikipedia.org/wiki/Polystyrene#Incineration https://en.wikipedia.org/wiki/Polystyrene#Incineration > If polystyrene is properly incinerated at high temperatures (up to 1000 °C) and with plenty of air (14 m3/kg), the chemicals generated are water, carbon dioxide, and possibly small amounts of residual halogen-compounds from flame-retardants. > When polystyrene was burned at temperatures of 800–900 °C (the typical range of a modern incinerator), the products of combustion consisted of "a complex mixture of polycyclic aromatic hydrocarbons (PAHs) from alkyl benzenes to benzoperylene. Over 90 different compounds were identified in combustion effluents from polystyrene." The American National Bureau of Standards Center for Fire Research found 57 chemical by-products released during the combustion of expanded polystyrene (EPS) foam. Yes, you can burn it... but the things you make out of it unless you are really trying to burn it (and then its a burn it to dispose of it rather than get energy from it) leave some less than desirable compounds.

orangepurple 4y ago
Yeah there may be awful byproducts at burn temperatures required for optimal power generation but if they can be captured/condensed/solidified they can be collected as solid waste and buried.
- KennyBlanken 4y ago
  Yeah, let's just bury those toxic cancer-causing compounds! What could possibly go wrong? looks over at the 1300 superfund sites around the nation
- shagie 4y ago
  The energy to condense out and capture the undesirable products becomes comparable to the energy capture it. Japan's approach isn't because they need energy but rather that they are trying to minimize landfill (as its an island and space is at a premium). The resulting products are carcinogenic toxic waste - which comes with additional challenges for disposal. In the US, it is likely more desirable to bury the inert polystyrene rather than trying to deal with the PAHs ( https://en.wikipedia.org/wiki/Polycyclic_aromatic_hydrocarbon https://en.wikipedia.org/wiki/Polycyclic_aromatic_hydrocarbo... ) and other byproducts. The article is describing a process where UV light and a catalyst break down/transform polystyrene into diphenylmethane ( https://en.wikipedia.org/wiki/Diphenylmethane https://en.wikipedia.org/wiki/Diphenylmethane ) which is a feed stock for many other (useful) processes. The paper referenced in the article is Cascade degradation and upcycling of polystyrene waste to high-value chemicals https://www.pnas.org/doi/10.1073/pnas.2203346119 https://www.pnas.org/doi/10.1073/pnas.2203346119
noselasd 4y ago
Is there currently a bottleneck that prevents burning it at 1000°C and getting energy out of it ? Sounds like business opportunities ! Make an practical incinerator ?

loudmax 4y ago

Wouldn't it be better to bury plastic in landfills? Keep the stuff out of the ocean, but I don't understand the harm in landfills. Put that carbon back in the ground where it came from.