Science Forums 2

[CraigD]

Originally Posted by freeztar

What do you mean by this? H2 and CH4 are produced naturally through the pyrolysis. I guess the "reformed" part is throwing me off.

Hydrogen reforming refers specifically to the process of extracting hydrogen (and, as a by-product, CO) from methane (CH4) by adding water and heat – it’s thus commonly termed “steam reforming”, and is how most hydrogen gas is currently produced. I was generalizing the term a bit – perhaps inappropriately – to refer to any process that creates one fuel from another.

In this more general sense, pyrolysis – the simplest form of which I’m aware consists of simply capping a large mass of organic waste and using the resulting methane at the pressure the system produces – is a reforming process. Like many practical fuel reforming schemes, the added energy – heat - needed for the reaction is supplied by the source fuel itself. A famous, small-scale system of this kind was one promoted by the PRC government for rural use, in which the waste manure from a single household produced cooking and lighting gas for the house.

Burning the methane produced by this, or any pyrolysis system, produces less energy than burning the feed fuel (manure, etc.), but is much cleaner burning, and easier to deliver to burners, lamp mantles, fuel cells, etc.

Fuel from biomass seems a very good solution for situations where large biomasses are available and there’s a need for gas fuel, but gas fuels aren’t ideal for all applications. In particular, they’re not ideal for vehicles. And, as with other renewable fuel schemes, I’m unsure if sufficient biomass exists, and whether facilities to gasify it can feasibly be made, to 100% replace the power needs currently satisfied by fossil fuels.