Re: GAS-L: Internal Combustion with Producer Gas

[Prof P P Parikh <parikh@me.iitb.ernet.in>]

Dear Dr. Reed

The quantity named as volumetric mixture calorific value defined as the
quantity of heat content of one unit vol. of the mixture is what really
decides the power capacity which can be realised by replacing one fuel by 
another. This quantity not only depends upon the cal value of the fuel
but also the stoichiometric air/fuel(by vol.) reatio. Where as the
air/fuel ratio for natural gas is 10 the same for producer-gas works out
to be very close to 'one'. The heat input capacity and therefore the
output capacity of the machine are not very different for natural-gas and 
producer-gas. There is very little need therefore for enlarging the inlet 
manifolds. In case there arises a need for enlargement of inlet manifold, 
it will not be just that, even the valves will need redesign snce that is 
the main controlling area which decides the maximum inflow rate.
Regards
Mrs Parikh

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Prof. (Mrs.) P.P.Parikh          Phone  Office : 5723496, 5767548 
Dept. of Mechanical Engg.                        5722545 Ext. 7548 / 8385 
I.I.T. Bombay				Home   : 5704646 	
Mumbai 400 076 INDIA		 Fax	Office : 5723496, 5723480
		
                    email : parikh@me.iitb.ernet.in    			   
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

On Mon, 24 Apr 2000 Reedtb2@cs.com wrote:

> Dear Andrew et al:
> 
> I have been collecting the plusses and minuses of having relatively low 
> energy producer gas.  
> 
> The energy content of producer gas is typically 4.5-5.5 MJ/nm3, considerably 
> less than the 94.01 gross (86.49 net) mJ/nm3 for propane; 37.69 (33.9) for 
> methane; 12 for CO; or 12.11 (10.2) MJ/nm3 for H2.  This is due to the 
> typical 50% dilution by N2 and 15% by CO2 and H2O.  
> 
> Therefore it is idfficult to store or pipeline producer gas.  On the other 
> hand it is relatively easy to produce where it is needed compared to propane 
> or methane!
> 
> During WWII the emergency retrofitting of gasoline engines resulted therefore 
> in a derating of 35-50% from that on gasoline, a big penalty for existng 
> engines initially chosen for gaoline.  
> 
> There are a number of cures for this problem.  One plus of producer gas is 
> that the octane rating is well in excess of 150, so (using the Tom Reed 
> octane rule:  octane no. ~ 10 X maximum compression ratio without knocking) 
> one can gain the derating back by increasing the CR of the engine, using a 
> turbo supercharger or just using a bigger engine.  Another problem is that 
> the intake manifold must be sized to the larger quantity of gas flow.  
> 
> Modern cars tend to have lots of excess power (unless you live in the 
> mountains).  In all other applications, choose an engine of adequate 
> capacity.  
> 
> Yours truly,                        TOM REED                        CPC/BEF
> 
> In a message dated 4/19/00 4:25:11 PM Mountain Daylight Time, 
> andrew.heggie@dtn.ntl.com writes:
> 
> << 
>  >Basically -- I was going to prove by math modeling why it is hopeless to
>  >get maximum power from an internal combustion engine using producer gas in
>  >a manner that all would grasp -- to the entire list.
>   >>
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