[Digestion] Response _ Biogas appliances

[Hoysall Chanakya]

Dear Dr Tumwesige,
Done well and is self contained.

Would you like to supplement that the primary gas:air mixing should be at
stoichiometric ratio (calculated based on CH4 content) and secondary air
is at the burner ports (top openings).  Further, methane /biogas always
burns with a blue flame and so a blue flame cannot be used as an indicator
for correct air-fuel ratio.  At ideal conditions, the flame burns with a
hissing sound and the flame does not touch the burner tops but burns 2-3mm
above.
best wishes
Chanakya




> Dear All,
>
> I am writing a paper on biogas appliances, below is an extract from the
> paper.
>
> All gas burners follow the same principle; the force which drives the gas
> and air into the burner is the pressure of gas in the pipeline. A biogas
> stove can have single or double burner with varying gas consumption rates
> ranging from 220 dm3 hr-1 to 450 dm3 hr-1 at standard temperature and
> pressure. This consumption rate results from the pressure provided by the
> biogas plant and the diameter of the inlet pipe. The jet at the inlet of
> the burner increases the gas speed, so producing a draft that sucks
> primary
> air into the pipe. The primary air must be completely mixed with the
> biogas, and this is achieved by widening the pipe to a minimum diameter,
> which is in constant relation [JUS1] <#_msocom_1> to the diameter of the
> jet. The widening of the pipe again reduces the speed of the gas. This
> diffuse gas goes into the burner head. The burner head is formed in such a
> way as to allow equal gas pressure everywhere before the gas/air mixture
> leaves the burner through the orifices at a speed only slightly above 0.25
> ms-1, the specific flame speed of biogas. More oxygen (secondary air) is
> supplied by the surrounding air to enable final combustion.
> ------------------------------
>
>  [JUS1] <#_msoanchor_1>Specify what this constant relationship is plus
> reference
>  Please, is some one in position to provide more information on the
> highlighted section of the extract?
>
> Thank you in advance,
>
> Regards
> --
> Vianney Tumwesige
> Director - Green Heat (U) Ltd  [image: Picture]
> P.O. Box 10235
> Kampala-Uganda
> 256 (0) 71 237 9889
>
> "The more people are self sufficient in cooking fuel, the more personal
> and
> financial freedom they have." - Emma Casson
>
>
>  <http://trustvianney.wordpress.com/>
>
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> for more information about digestion, see
> Beginner's Guide to Biogas
> http://www.adelaide.edu.au/biogas/
> and the Biogas Wiki http://biogas.wikispaces.com/
>
>


-- 
Dr. Hoysall Chanakya
Centre for Sustainable Technologies
(Assoc. Faculty at Centre for Infrastructure, Sustainable Transport and
Urban Planning (CiSTUP) and Centre for Contemporary Studies)
Indian Institute of Science, Bangalore 560 012
ph 91-80-2293 3046; fax-91 80 2360 0683


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