[Digestion] Dual fueling a diesel

Thu May 8 11:23:09 CDT 2008

Thanks Rex, and to all who have responded!
I have taken a look at the website and it seems reasonably easy.
Are there no explosion concerns about bleeding it into the air intake area?
I am thinking if the engine room or air intake gets real hot as it can here 
in Jamaica.
I am wondering how much percent diesel usage I could possibly replace by 
this arrangement?

Mike
JAMAICA

----- Original Message ----- 
From: "Zietsman, Rex" <Rex at Process.co.za>
To: <digestion at listserv.repp.org>
Cc: "Michael Barnett" <dreadlox at cwjamaica.com>; "Jim and Amy Rankin" 
<ajrankin at westal.net>; "Shelby" <shelby at biogaspower.co.za>
Sent: Thursday, May 08, 2008 10:11 AM
Subject: Dual fueling a diesel

Hi Mike,

I can only support what Jim has said. I recently visited Shelby Tyne on
his farm and saw his polyethylene chicken manure digesters. Shelby does
pretty much what Jim says which is to simply bleed the biogas into the
air intake of his diesel engine. You can visit his website on
www.biogaspower.co.za and he is such a gentleman that he will help you
with your problems as well.

Kind regards
Rex

Date: Mon, 5 May 2008 15:08:16 -0500
From: "Michael Barnett" <dreadlox at cwjamaica.com>
Subject: [Digestion] Sucessful small engine Conversion experience?
To: "The Digestion Discussion List" <DIGESTION at LISTSERV.REPP.ORG>
Message-ID: <016b01c8aeeb$c2f45840$0201a8c0 at Mikey>
Content-Type: text/plain; charset="iso-8859-1"

Dear friends,

I am considering an environmental proposal in a few months that could
give our property more power through a hybrid arrangement in tandem with
an existing solar energy system.

Can anyone tell me of their experiences converting a small generator to
run on biogas, and maybe of the modification experience on a standard
"off the shelf" genset?
I would appreciate any papers, documents and other info on "real life"
exercises.

Thanks,

Mike Barnett
http://www.newhorizonsjamaica.org/
http://picasaweb.google.com/NHCOMSkillTrainingFacility/
JAMAICA

------------------------------

Message: 2
Date: Mon, 5 May 2008 23:41:07 -0500
From: "Jim and Amy Rankin" <ajrankin at westal.net>
Subject: Re: [Digestion] Sucessful small engine Conversion experience?
To: "Michael Barnett" <dreadlox at cwjamaica.com>, "The Digestion
Discussion List" <DIGESTION at LISTSERV.REPP.ORG>
Message-ID: <A3268F5261464CC3BCC7C41CF58EAE75 at RankinPC>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original

Hi Mike,
The biogas conversion would be easier on an engine that is already setup
for propane vapor or Natural gas use.  then it's a matter of opening the
gas adjustment on the vapor mixer/carburetor to account for the %CO2
that's mixed with the biogas compared to pure LPG vapor or natural gas.

If you are likely to need more power than your biogas can supply, you
might want to supplement a diesel engine (maybe like one of the Lister
or "listeroid" generators) with biogas.  These engines are very long
lived and reliable running on diesel, biodiesel or vegetable oil and
many are used around the world for the only source of power as opposed
to the common small portable backup/emergency set which probably will
not ever run more than 10's of hours before neglect and age result in it
being junked if it doesn't fail on it's own while under load.

Supplementing a diesel engine can be pretty simple if the load is
stable, you adjust the flow of biogas into the air intake of the diesel
engine after
it is started, running at the desired speed and the load applied.   As
the
biogas comes in, the diesel governor will cut back to keep RPM from
rising.
If the biogas runs low or load increases, the governor will feed more
diesel fuel and attempt to meet the demand.  If the demand for power is
greater than the engine can supply,  it may overheat since it's
essentially being overfueled even though the diesel injection system may
not have reached it's set fuel limit.

This works well on a fairly constant load maybe like a battery charging
setup but would not work where load varied down.  If load is allowed to
decrease, there has to be some way to cut back on the biogas so the
diesel doesn't overspeed.  I expect it could be done with a separate
governor that just metered the biogas into the diesel intake as opposed
to the normal spark engine governor that controls the throttle plate.

You would have the expense of the diesel essentially running at idle
speed just to ignite the biogas, but you get a heavy duty/continuous
duty engine, backup fuel capability and the ability to burn very low %
methane biogas if
that were to be an issue.   If you use a spark engine, you probably
should
oversize it by about 100% compared to one that is rated on gasoline or
LPG.

You don't mention what size generator you are considering.

Jim

> I am considering an environmental proposal in a few months that could
> give our property more power through a hybrid arrangement in tandem
> with an existing solar energy system.
>
> Can anyone tell me of their experiences converting a small generator
> to run on biogas, and maybe of the modification experience on a
> standard "off the shelf" genset?
> I would appreciate any papers, documents and other info on "real life"

> exercises.
>

------------------------------

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End of Digestion Digest, Vol 23, Issue 2
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