[Gasification] gas quality and engine lifespan?

[Mark Ludlow]

Great practical advice, Ken!

Often times we overlook real-world considerations in our pursuit of "trick"
solutions that are really just armchair musings.

Do you think the lubrication problems with clean wood gas are inherently
worse than, say, the use of propane or NG as a fuel? While my gut feeling is
that you are making a valid observation, I'm trying to relate it to some
physical characteristic of the gas that would actually result in less
effective lubricity (assuming that it's purged of abrasive ash residues).
Ever consider top-lubing with a co-current injection of funky oil, leaving
the good stuff to lube the bearing surfaces?

Mark

-----Original Message-----
From: gasification-bounces at listserv.repp.org
[mailto:gasification-bounces at listserv.repp.org] On Behalf Of Ken Calvert
Sent: Saturday, July 07, 2007 10:18 PM
To: Discussion of biomass pyrolysis and gasification
Subject: Re: [Gasification] gas quality and engine lifespan?

Javier, take it from an old timer,  the biggest wear factor with good clean 
dry producer/wood gas is not the tars but the fact that it is hot and dry 
and it will lick the oil off the cylinder walls.  The tars will impact and 
get stuck in the inlet manifold and not much gets onto the cylinder walls. 
To get any thing like a long life out of a PG motor you have to over 
lubricate.   And you can't use the usual kinds of upper cylinder lubricants,

because you haven't got any liquid fuel to dissolve them in.
The usual thing in WW2 was to leave out the oil seal rings on the bottom
flange of the pistons.  That means that you will use a lot more lubricating 
oil, but your question is about longevity not about running costs or the 
costs of  lubrication.
     For the purposes of  generation and experimentation,  by far the 
easiest way is to choose a very common automotive engine that sells for 
cheap at the local auto-wreckers  and keep yourself a supply of spares.  If 
they are already burning a bit of oil, then that is exactly what you want 
because they will last longer than a new motor with tight rings.  Derate the

load factor and they will laqst for years. The one thing that I can't answer

is whether the polarised metal additives and super duper things that you can

put in your lubricating oil nowdays will be of any help.  I would suspect 
that the amount of oil you loose would make their constant replacement 
rather expensive. I just hope that someone a mite younger than me can come 
up with the latest and greatest to improve the situation.   Sincerely,   Ken

Calvert.

----- Original Message ----- 
From: "Javier Bonet" <jabonet at runbox.com>
To: <gasification at listserv.repp.org>
Sent: Sunday, July 08, 2007 6:30 AM
Subject: [Gasification] gas quality and engine lifespan?


> What is the life expectancy of a piston engine running on wood gas?
> is there any chloride and sulfur gases being generated that will reduce 
> the life span of the engine, how do you cleans tars and avoid them from 
> getting into the engine?
>
> Thanks, Javier.
>
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