[Stoves] venturi system -ratios of air and gas?

[Jock Gill]

Good morning:

It would be great to work with a 3D ceramic printer to make custom designs (shapes, dimensions) of ALL the components.  That would be very interesting.

Cheers,

Jock

Jock Gill
P.O. Box 3
Peacham,  VT 05862

Cell: (617) 449-8111

google.com/+JockGill

:> Extract CO2 from the atmosphere! <:

Via iPad

> On Jan 9, 2016, at 7:05 AM, Julien Winter <winter.julien at gmail.com> wrote:
> 
> Hi folks;
> 
> I believe that thorough mixing of secondary air with somewhat (don't know how much yet) more than the stoichiochmetric requirement for oxygen is important for clean-burning wood gas in natural draft burners.  This is because the wood gas is very complex containing fast-reacting H2, CO, CH4 and slower reacting tars.  If oxygen is sufficient, then the fast gases, slow gases, suspended droplets and particles, and secondary products like soot, will oxidize in close proximity.  If oxyen is limited, then fast gases will react, and we loose heat from the site of reaction; heat that would have provide activation energy, and accelerated the reaction rates of the slower species.  
> 
> Conservng the heat is important for people who design gas burners that add air in stages.  It is also why I am cautious about adding secondary air through the side-walls of ND-TLUD reactors.  If this isn't done carefully, we end up with unburnt wood gas and products of incomplete combustion that we can't ignite because the reactants are too cold and too dilute. 
> 
> For a TLUD, the stoichiometric requirement for secondary air will depend inversely on the rate of primary air, where the combustion begins.  I recall that Mukunda lab in India reported that the ratio of secondary to primary air changed from 6:1 to 3:1 as the rate of forced draft gasification of pellets increased.
> 
> Cheers,
> Julien
> 
> 
> -- 
> Julien Winter
> Cobourg, ON, CANADA
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