[Gasification] Question: Connecting a gasifier to a micro CHPunit

[Art Krenzel]

I support Doug's assertion that there are technical complications for the 
use of producer gas in a Stirling application that require more long term 
stringent gas qualities than using it in a more common internal combustion 
engine.

Also, why use producer gas in an electrical conversion process that is only 
8% efficient when it can be used in a 30+% efficient such as a simple diesel 
engine?

Art Krenzel


----- Original Message ----- 
From: "doug.williams" <Doug.Williams at orcon.net.nz>
To: "Discussion of biomass pyrolysis and gasification" 
<gasification at listserv.repp.org>
Sent: Saturday, September 01, 2007 12:26 AM
Subject: Re: [Gasification] Question: Connecting a gasifier to a micro 
CHPunit


> Hello Ian,
>
> You Ask:
>
>> This is my first time posting here, so excuse me if I seem out of touch -
>> because I am. I was wondering though whether there had been any
>> consideration given to connecting a gasifier to a small CHP plant like 
>> the
>> one produced by Whispertech of New Zealand? It seems to me that anything
>> which gets too hot to touch should really be mated with a stirling 
>> engine.
>
> I guess in the context of how you phrase this question, you are looking at
> the waste heat that radiates from the casing, not use the gas made in the
> gasifier to run the Stirling. Personally, I have not heard of any systems
> set up like this, as it would require the Stirling engine manufacturer to
> get involved with the gasifier manufacturer, and that is not an easy
> marriage of technology to organize.
>
>> The reason I mention whispertech is that they seem to have gotten the
>> round
>> the wear problem in a closed cycle.
>
> In 2004-5, I was asked by a third party to look at the requirement to 
> gasify
> the WhisperTech, and the result was the Micro Class Gasifier that you can
> see on the Fluidyne Archive www.fluidynenz.250x.com     I had also worked
> with a German Stirling designer, and had discussions with other Stirling
> manufacturers about their engines need, by way of head heating, it was 
> clear
> that producer gas had to be meticulously clean.  To date, I have not found
> any Stirlings that are actually operating with a gasifier in a commercial
> application.
>
> Returning to the WhisperTech, I had the opportunity to see one opened up 
> in
> June this year, and learnt more in a few minutes from the salesman, than I
> could extract through third parties over weeks! Their engine has a ceramic
> cover to the head, and this would make a huge difference to the problem of
> ash contamination. In fact, it is possibly the only way you could use
> producer gas for this type of application, in order to create the
> incandescent surfaces for heat radiation transfer.
>
>> In any case given the high operating
>> efficiency of CHP it seems to make sense to me that a gasifier should be
>> part of something larger, rather like we have a camera in our handphones
>> these days. So has this been considered?
>
> In the end, it boils down to economy of scale. The WhisperTech puts out 
> less
> than 1kWe/hr, and that takes 3kg of wood pellets at $0.10/kg to run, and 
> you
> still have to deduct the power needed to run the gasifier The cost of the
> WhisperTech and gasifier, plus fuel pellets, is a long way from being
> economic, and even if really desperate, it would not be a good option with 
> a
> gasifier. CHP is well proven with conventional engine generation systems,
> but also expensive, although in a DIY situation, you could clobber up a
> system that will work quite well at low cost.
>
> Hope this helps.
>
> Doug Williams,
> Fluidyne Gasification.
>
>
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