3 ms·

Chemistry-ignoramous question: Is there a burn-temperature above which everything dangerous is basically rendered inert? I.e., you make stuff so hot that what

Chemistry-ignoramous question: Is there a burn-temperature above which everything dangerous is basically rendered inert? I.e., you make stuff so hot that whatever survives is perma-bonded to oxygen, carbon, chlorine, fluorine, etc., and has almost zero chance of reacting with living creatures? (Ignoring radioactive stuff, I mean.)

PaulHoule 3y ago
Not really. Even with a plasma torch https://en.wikipedia.org/wiki/Plasma_gasification https://en.wikipedia.org/wiki/Plasma_gasification you need to clean up the syngas to get rid of dioxins with a charcoal filter or something like that. The plasma torch is supposed to convert the organic materials in municipal waste (e.g. food waste, plastic, wood) to syngas and then vitrify the remainder as glass particles that trap toxic heavy metals (you could use it as a material for roads and buildings.) Allegedly you can burn the syngas to make enough electricity to run the torch and still sell some to the grid. I guess you'd want to try to capture mercury before it goes up the stack. They built a few small (like 5 MW) plants to test the idea but attempts to scale up to 50 MW. For a long time the technology belonged to one of Westinghouse's ghosts (like the one that owns the AP1000) but they are still ordering AP1000s but nobody is ordering plasma torches for municipal waste.
- rapjr9 3y ago
  I asked my local waste disposal company why they don't buy a plasma gasification system and they told me that the plants require so much trash as fuel that to keep them fed they'd have to haul trash from three states. It wasn't affordable to buy one just for local operation. Here's the history of attempts and current projects: https://en.wikipedia.org/wiki/Plasma_gasification_commercialization https://en.wikipedia.org/wiki/Plasma_gasification_commercial... These are definitely large scale, large area systems and there have been some engineering problems. A few seem to be operating successfully. Even if the net energy production is zero that's better than it being negative. Financing has been a problem also. It still produces CO2 also, so there is that to consider. It greatly reduces hazards in the waste stream though, so it seems better than a landfill. I'm not sure it would be a good idea to turn the glass plus heavy metals that is produced into building or road materials.

PaulHoule 3y ago

Not really. Even with a plasma torch https://en.wikipedia.org/wiki/Plasma_gasification https://en.wikipedia.org/wiki/Plasma_gasification you need to clean up the syngas to get rid of dioxins with a charcoal filter or something like that. The plasma torch is supposed to convert the organic materials in municipal waste (e.g. food waste, plastic, wood) to syngas and then vitrify the remainder as glass particles that trap toxic heavy metals (you could use it as a material for roads and buildings.) Allegedly you can burn the syngas to make enough electricity to run the torch and still sell some to the grid. I guess you'd want to try to capture mercury before it goes up the stack. They built a few small (like 5 MW) plants to test the idea but attempts to scale up to 50 MW. For a long time the technology belonged to one of Westinghouse's ghosts (like the one that owns the AP1000) but they are still ordering AP1000s but nobody is ordering plasma torches for municipal waste.

rapjr9 3y ago
I asked my local waste disposal company why they don't buy a plasma gasification system and they told me that the plants require so much trash as fuel that to keep them fed they'd have to haul trash from three states. It wasn't affordable to buy one just for local operation. Here's the history of attempts and current projects: https://en.wikipedia.org/wiki/Plasma_gasification_commercialization https://en.wikipedia.org/wiki/Plasma_gasification_commercial... These are definitely large scale, large area systems and there have been some engineering problems. A few seem to be operating successfully. Even if the net energy production is zero that's better than it being negative. Financing has been a problem also. It still produces CO2 also, so there is that to consider. It greatly reduces hazards in the waste stream though, so it seems better than a landfill. I'm not sure it would be a good idea to turn the glass plus heavy metals that is produced into building or road materials.