Gasification vs Pyrolysis

I had thought pyrolysis is a step of gasification, but this makes them sound like two distinct processes. What am I misunderstanding?

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They are related, but two different things. Pyrolysis is making char and have byproducts.
Gasification is using the char to make gas.

The line gets fuzzy with woodgas because the pyrolization part is done in the gasifier. The char bed actually cracks the tars and other byproducts into usable gas before getting gasified itself. The only goal is to get the gas.

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Thank you Sean, that makes sense!!!

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This is a good read if you haven’t seen it.

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Seems like there are the two general processes, but they are similar enough that they often overlap. Hard to separate them in the real world, certainly in a wood gasifier. They are more distinct with a charcoal system, where the pyrolysis is separate, in the charcoal making. Even there, the article shows some overlap. It says pyrolysis takes place without oxygen, but then says it has the advantage of not requiring an external heat source. I’m thinking you either need an external source, or enough oxygen for flaming pyrolysis, so it goes on its own.

I guess if you’re assembling molecules like CO or H2, then it’s not just pyrolysis.

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