GAS-L: Gasifier fundamental question

["Tom Reed" <tombreed@attbi.com>]

Dear Vernon, Crispin and All:

 

Recently I said...

 

The air fuel ratio for volatiles in a dry fuel is about 1.  For charcoal it
is 6! 

 and Vernon asked...

 

Tom, would you be so kind as to elaborate?  I gather that to burn the charcoal, the required air to fuel ratio is 6.  But I'm not clear about what air to fuel ratio is required to gasify the wood.  And what air to fuel ratio is then required to combust the pyrolysis gases?

More recently I stressed that proper primary and secondary air distribution was all important in gasifying and burning charcoal and biomass.  Since there is such a difference between biomass and charcoal let me explain in more detail.  The explanation involves only simple chemistry.

 

First lets look at carbon (charcoal) combustion with oxygen:

 

                                                    C +     O2 ==> CO2

Molecular weights                          12       32           44     (g/mole; lb/lbmole etc.)

 

So the oxygen/fuel ratio for carbon combustion is 32/12 = 2.66...

 

It gets a little more complicated with air since each oxygen carries 3.76 N2 with it.

                                                    C + 1/2 O2 ==> CO

Molecular weights                          12       16           28     (g/mole; lb/lbmole etc.)

----- Original Message -----

From: VHarris001@aol.com

To: stoves@crest.org

Sent: Thursday, May 09, 2002 11:27 AM

Subject: Re: Gasifier fundamental question

In a message dated 04/14/2002 6:33:29 PM Eastern Daylight Time, tombreed@attbi.com writes:


Thanks
Vernon Harris