[Bioconversion] methane digester and greenhouse gas reductionfordemonstration post-carbon world home

[AJH]

On Wed, 13 Jun 2007 11:53:23 +0930, Paul Harris wrote:

>Anaerobic destruction, which can be low tech/simple, gives of methane,
>which should be used as fuel (high grade heat)

I'm all for fighting your own corner Paul but this is biased. It looks
to me like, other than oils, biogas is the simplest of the biomass
derived renewables to be converted in an engine to give motive power.
Not only is it high calorific value but it is also relatively simple
to clean.


> and leaves a good organic
>compost.

And there's the rub, digestion is best for plants which haven't become
"woody", the digestion process favours simple carbohydrates. 

Even then how much carbon (the carbon being a measure of the fuel
available in a carbohydrate) is left in the residue of an economic
digester?

Has anyone any figures for digestion of grass silage?
>
>Combustion gives heat and ash/smoke, which has little organic material
>but does contain plant nutrition and smoke is an eye/lung irritant.

Poor combustion gives smoke.

Combustion destroys plant available nitrogen compounds and dumps
phosphorus ones into the atmosphere.

AJH