[Gasification] Gasification Digest, Vol 17, Issue 10Re: anaerobicc digester gas for IC engine

David Coote dccoote at mira.net
Thu Jan 19 18:05:03 CST 2012

Hi Anand,

How do you find engine maintenance requirements running on biogas as against running on diesel?



Message: 2
Date: Thu, 19 Jan 2012 12:27:58 +0800
From: Anand Karve<adkarve at gmail.com>
To: Discussion of biomass pyrolysis and gasification
	<gasification at lists.bioenergylists.org>
Subject: Re: [Gasification] anaerobicc digester gas for IC engine.
	<CACPy7Sd8upLZ68jwQpnsip4mU80waunCAaeN5WqZ4Ggu4p+muQ at mail.gmail.com>
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Dear Phillip,
I have been running two engines for several years on raw  biogas without
cleaning it. One is attached to an electricity generator and the other one
is attached to our char briquette extruder. Please note that we are not
selling our biogas, but using it privately.
We make our biogas from high calorie food waste and green leaves. It
contains about 60 to 65% methane, about 34 to 40 % carbon dioxide, less
than 1 % H2s and NH3 and some water vapour. When one runs an internal
combustion engine, the air that enters the engine has about 80% nitrogen
and when it is raining outside, the air entering the engine is saturated
with water vapour, as in the case of biogas. The nitrogen, carbondioxide
and water vapour just dilute the fuel gas, but if the mixture contains
enough of the combustible gases, it can be used in an internal combustion
engine.  We are also using producer gas at another location to run an
electricity generator. Even the producer gas, which is used as fuel in this
case, has nitrogen, sulphur dioxide, nitrous oxide and carbon dioxide. Just
25 years ago, the world used high sulphur diesel. It did not harm the
engine. The sulphur content in the fuel was reduced out of environmental
considerations. However, the environment need not worry a user of biogas or
producer gas, because if the biomass does not get converted into biogas in
an anaerobic digester, it is going to rot outside the digester, in nature,
and release the sulphur and nitrogen in their oxidised forms  Both wood and
biogas are being used as cooking fuel and they release the substances
mentioned above. If you used a mixture having 97% carbon dioxide and just
3% methane, it won't be possible to run an internal combustion engine on
it. But with biogas and producer gas, one can. Removing the carbon dioxide,
moisture, ammonia and H2S from biogas just adds to the operating cost.

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