[Digestion] Len's suggestion

[Duncan Martin]

There's a problem with bike inner tubes (and with old-fashioned rubber party 
balloons): it takes quite a high presssure to inflate them, higher than a 
bench-scale digester is likely to deliver without leaking.

Rubber party balloons are also quite permeable to air - and no doubt to 
biogas too, as well being easy to burst. How often does one survive more 
than a few days after a party? If it doesn't burst, it shrivels away. I 
doubt they'd hold biogas for long - in fact methane might pass through even 
faster than air.

In contrast, the "foil" balloons* suggested in my posting are impermeable 
(designed to hold HELIUM for several days, at least) and almost bomb-proof. 
Try sitting on one if you doubt me - but make sure there are no spikes under 
it - or on your trousers!! They can last for months in the lab.

And they don't initially inflate by stretching, merely by changing shape 
from flat to "full". So the back-pressure is almost zero, provided you 
change balloons before the first balloon has reached full size.

(*I guess they are really a polymer/foil film composite.)

Best regards

Duncan

================================
CONTACT DETAILS
Duncan J Martin, PhD, CEng, CSci, MIEI, MCIWM, MIChemE
24 Townsfield, Cloughjordan, N Tipperary, Ireland
Home: +353 505 42087
Mobile: +353 86 8377 906
Email: duncanjmartin at eircom.net
================================

----- Original Message ----- 
From: "Len Walde" <sigma at ix.netcom.com>
To: "stephen cullinan" <stephencullinan at gmail.com>; 
<digestion at listserv.repp.org>
Sent: Friday, August 03, 2007 9:22 PM
Subject: Re: [Digestion] young scientist project -- suggestion from Len


>a balloon, a bike tire inner-tube, or the like, should to the trick to
> collect and store the gas.
>
> Good luck,
>
> Len Walde, P.E.
>
>
> ----- Original Message ----- 
> From: "stephen cullinan" <stephencullinan at gmail.com>
> To: <digestion at listserv.repp.org>
> Sent: Friday, August 03, 2007 5:28 AM
> Subject: [Digestion] young scientist project
>
>
>>I have developed a mini anaerobic digester. It consists of a plastic can
>> about 30cm by 30cm by 90cm.I have cut a hole in the lid of the can. In
>> this
>> lid I placed a mini agitator which contained a pipe leading from the top
>> of
>> the inside of the plastic can to the outside transporting any gas
>> produced.Iplaced three of these in a plastic
>> box.I placed a small immersion heater into the box and filled the box 
>> with
>> water. However this is where I am stuck. I need some help in thinking up
>> of
>> a way of trapping the gas
>> _______________________________________________
>> Digestion mailing list
>> Digestion at listserv.repp.org
>> http://listserv.repp.org/mailman/listinfo/digestion_listserv.repp.org
>> Beginner's Guide to Biogas
>> http://www.adelaide.edu.au/biogas/
>> http://info.bioenergylists.org
>>
>
>
>
> _______________________________________________
> Digestion mailing list
> Digestion at listserv.repp.org
> http://listserv.repp.org/mailman/listinfo/digestion_listserv.repp.org
> Beginner's Guide to Biogas
> http://www.adelaide.edu.au/biogas/
> http://info.bioenergylists.org
>
>
>
> -- 
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.5.476 / Virus Database: 269.11.2/933 - Release Date: 02/08/2007 
> 14:22
>
>