Chemistry Forums for Students > Organic Chemistry Forum
Pyrolysis of wood
Borek:
Or they make a lot of smoke.
Enthalpy:
--- Quote from: gatewood on February 21, 2020, 09:59:04 PM ---I heard that you could extract useful hydrocarbons, such as benzene, xylene and toluene from the destructive distillation of wood and charcoal.
--- End quote ---
These three compounds are useful but very cheap. Extracted train-wise from petrol, with very little transformation. I can't imagine wood pyrolysis on reasonable scale competing against that. Same for methanol and more compounds.
More generally, petrol and coal too are pyrolysis products of wood and similar substances. You find similar compounds in all of them. They are the compounds that form indistinctly from very rough and uncontrolled reactions. You get aromatics because of the H/C ratio and the stability of aromatic rings. Lighter alcohols, aldehydes and ketones at the beginning, polycyclic aromatics at the end.
In this context, I doubt that a major product of wood pyrolysis has a market value not spoiled by coal and petrol products. What you might try:
Find a minor compound that is not usually extracted from coal nor petrol. Since petrol is already well pyrolysed and coal even more, you might have better chances with the early pyrolysis products. Just a gut feeling. If you obtain for instance a solvent with pleasant odour, different from turpentine, it has more value than white spirit.
Or do more than a bare pyrolysis. Add some cheap compound (natural gas, alcohol, aldehyde, amine...) and check is something more useful comes out. Again, early products should be more differentiated than late ones.
Pyrolysis makes many moderate carcinogens, so you'll have to sort out the products.
gatewood:
--- Quote from: billnotgatez on February 26, 2020, 02:05:36 AM ---From WIKI
--- Quote ---Modern methods employ retorting technology, in which process heat is recovered from, and solely provided by, the combustion of gas released during carbonisation.[5] Yields of retorting are considerably higher than those of kilning, and may reach 35%-40%.
--- End quote ---
It appears that during the commercial process they burn the gasses produced during the charcoal process as fuel to produce the charcoal.
--- End quote ---
They do that to avoid spreading the volatilites all over the place (as Borek mentioned). Extra heat is not necessary though, I guess it might speed up the process. Interesting.
Its actually pretty easy to do (if anyone is interested), a dense cloud of wood gas will quickly ignite and further break down into CO and CO2, which avoids extra contamination of carcinogenic compounds.
Which wiki article is that?
gatewood:
--- Quote from: Enthalpy on February 26, 2020, 07:13:43 PM ---
--- Quote from: gatewood on February 21, 2020, 09:59:04 PM ---I heard that you could extract useful hydrocarbons, such as benzene, xylene and toluene from the destructive distillation of wood and charcoal.
--- End quote ---
These three compounds are useful but very cheap. Extracted train-wise from petrol, with very little transformation. I can't imagine wood pyrolysis on reasonable scale competing against that. Same for methanol and more compounds.
More generally, petrol and coal too are pyrolysis products of wood and similar substances. You find similar compounds in all of them. They are the compounds that form indistinctly from very rough and uncontrolled reactions. You get aromatics because of the H/C ratio and the stability of aromatic rings. Lighter alcohols, aldehydes and ketones at the beginning, polycyclic aromatics at the end.
In this context, I doubt that a major product of wood pyrolysis has a market value not spoiled by coal and petrol products. What you might try:
Find a minor compound that is not usually extracted from coal nor petrol. Since petrol is already well pyrolysed and coal even more, you might have better chances with the early pyrolysis products. Just a gut feeling. If you obtain for instance a solvent with pleasant odour, different from turpentine, it has more value than white spirit.
Or do more than a bare pyrolysis. Add some cheap compound (natural gas, alcohol, aldehyde, amine...) and check is something more useful comes out. Again, early products should be more differentiated than late ones.
Pyrolysis makes many moderate carcinogens, so you'll have to sort out the products.
--- End quote ---
" Lighter alcohols, aldehydes and ketones at the beginning"
You know why is that exactly?
Thanks for the input, thats some pretty useful insight right there :)
Navigation
[0] Message Index
[*] Previous page
Go to full version