[Stoves] Solid oxide fuel cell

[AJH]

On Thu, 12 Oct 2006 15:24:03 GMT, steve wrote:

>I went to a fascinating event last night on microgeneration
>in the UK specifically, but one item seized my attention.
>The device was a solid-oxide fuel cell, and converted "gas"
>- ie methane or CO  into electricity in a chemical cell. The
>cell ran hot (750C) and was heated by the waste gas, not
>converted into CO2 as it generated electricity ! Efficiency
>was 50%.

This is probably more appropriate to [bioconversion] or [gasification]
my understanding was it was fed co+h2, from reformation of natural
gas, the hydrogen component migrated through the solid oxide to meet
an oxygen molecule and produce a electricity the larger CO molecule
carried on until it was oxidised to produce heat. My erstwhile
colleague went on to work with these in combined cycle with a gas
turbine, essentially the fuel cell forming the combustion chamber of
the gas turbine so both electricity and motive power were produced.
Theoretical conversions of up to 70% thermal input seem achievable
which looks good compared with Newcomen's 1/4% IIRC.
>
>The only "killer" is that the cell cannot tolerate sulphur,
>but a stack capable of generating 1kW was only abou 300mm
>high, and 150mm wide.

Contamination of the membranes and interfaces of fuel cells has
militated against their adoption in general but it could favour
biomass as the source of the syngas as this is a relatively clean raw
material.
>
>These,coupled with gasifiers, would make an interesting
>project indeed.

Indeed have a look at molten carbonate cells also.

AJH