I need help with my digester project ?

hello i   have   attached  a  drawing  of  a project  i   am   thinking about  , but   like ususla have some  questions i  need  help with.

1.  you  see on the drawing   i  have  included   a   storage tank.  Do you think  it will work    laid out like this?

2. How  can i    compress the  methane   enough to runa    smal  generator?

3.What would  be   the size  of  teh    safety  gas  valve   i should  purchase. I have no idea of  how   much pressure  a  smll  8 to 12 hp  generator takes to   run .

Any help anyone  can  give  woudl be  greatly appreciated.


digester drawing.PDF(616x348) 346 KB
rickharris6 years ago
NachoMahma6 years ago
.  Methane vapor has a fairly low energy density (not as many Btu/volume as gasoline, diesel, or LPG) so you may not be able to effectively convert a gasoline/diesel engine to use low-pressure methane. All the conversion kits I've seen use LPG. You might be be better off finding an engine designed to run on methane/natural gas. But I'm no expert.
rickharris6 years ago
In general digester run at low pressure - They are built from brick or poly tubing.

Your engine should draw as much methane as it needs so no pressurising is required.

a bigger problem may be converting the engine to run from a gas rather than a liquid fuel.

This in mind the blow off valve only needs to be a low pressure HOWEVER all the simple DIY digester plans I have seen don't have one at all.

have you fully researched this project?

I am not an expert in this field - you take my comments at your own risk.

andy1917 (author)  rickharris6 years ago
I have only did a little research on this at this point. I have never seen a pressure regulator either on a digester, but i am traditionally overkill on safety with everything i do.

my thoughts on the generator was that i woudl start with a propane fueled and reseacrh to find what adjustmenst have to made.

This is all in the baby stages. I have only filled up balloons in the past with methane andhad a little torch burning . Never attempted a engine. I figured they has to bea formula somewhere on size of digester for size of engine.

thanks for the response.