[Stoves] Effects of Steam on Combustion

[Paul S. Anderson]

Jeff,

When the H2O is introduced in a gasifier into the area of the redhot char near
the grate, the "water gas reaction" does occur (disassociation of the 2 x H2
plus O2).  The advantages are
1.  this reaction helps cool the grate so that it lasts longer, and
2.  The O2 helps drive the char-gasification, and
3.  The H2 can exit the gasifier chamber and be able to combust wonderfully AT
THE INTENDED LOCATION OF THE COMBUSTION, which is where we want the heat
(instead of the heat being low in the gasifier.)

I am speaking of gasifiers.  In other biomass fueled devices, I am not 
sure what
happens.

Others who understand better than I do can please revise what I have written.

Paul

-- 
Paul S. Anderson, Ph.D., Geography professor - Emeritus
Telephone:  USA-309-452-7072 (residence and office)
Internet site:  www.ilstu.edu/~psanders
For my gasifier stoves info, go to:
http://bioenergylists.org/contributors#Paul_Anderson


> On 5/25/07, Jeff Davis <jeff0124 at velocity.net> wrote:
>> Oil and Gas Burning Under Boilers
>> 231C
>> 1933
>>
>> Page 48
>> Effects of Steam on Combustion
>>
>> "The steam that is used for the purpose of atomizing the oil does not
>> increase the total heat resulting from combustion, although it may affect
>> the character of the chemical changes in certain parts of the flame so as
>> to produce a higher temperature at those points. It would seem that the
>> steam, under the effect of the high furnace temperature, is dissociated,
>> or separated, into its elements, oxygen and hydrogen, and that the
>> combustion of the hydrogen thus set free increases the heat of combustion.
>> However, it takes just as much heat to break up the steam into its
>> elements as is obtained by the subsequent uniting of those elements.
>> Consequently, if the combustion is perfect, the steam that enters the
>> furnace passes up the stack as steam, carrying away heat with it, and the
>> greater the amount of steam introduced, the greater will be the heat loss.
>> Thus, the introduction of steam into the furnace decreases the available
>> heat rather than increases it."


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