Dear Deepak and listers,
The issue of burner design and pressure control is one which needs some
careful planning. Biogas has a very low flame velocity, so if the flame
lifts from the burner, it means the flow rate of the biogas/air mixture
is too high, so the velocity from the flame port is faster than the
flame can burn.
If you are using burners from a reliable source, then the gas pressure
is too high. If you are using a floating drum, the weight of the drum is
too much. However, studies by SNV of burners made in different projects
suggests that the quality of burners from different places in Asia is
not consistent. (I say this as someone who helped design the one now
used by BSP Nepal, which was criticised by the SNV study). The biogas
wiki <http://biogas.wikispaces.com/Biogas+burners> has a section on
biogas burners, with a link to that SNV report. Our Nepal design used
too few flame ports. A larger flame port area would have reduced the gas
mixture velocity through the holes. You may need to look for a better
burner.
The simplest way to reduce gas pressure is to use a gas valve to control
the flow. Partly closing the valve will increase the pressure losses,
reducing the flow rate and the flow velocity. A longer lasting solution
is to use a pressure control valve.
Regards,
David F
On 31/03/2011 16:31, Deepak D. G. wrote:
Dear listeners,
I would like to consult on a issue of flame lifting.
I have installed 8 floating digesters and all are working well and the
gas production is also very good.
The only issue I have right now is the flame lifting issue, specially
with the latest installation. The latest installation, in a village in
Bali, has a capacity of 1000 liter gas tank and the distance between
the structure and the stove is about 20 meters. I used a combination
of a plastic tube and pvc of equal size and that is 1/2".
I can not get the flame burned immediately above the surface of the
burner but it is lifting. I have tried the same stove at home in which
the distance between the biogas and the stove is about 8 meters and
the flame is stable and not lifting.
Can anybody suggest solutions to this issue? thanks
Rgds,
Deepak
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--
********************************************************************
Dr David Fulford CEnv MEI, 15, Brandon Ave, Woodley, Reading RG5 4PU
[email protected] <mailto:[email protected]>, Tel:
+44(0)118 326 9779 Mob: +44(0)7746 806401
Kingdom Bioenergy Ltd, www.kingdombio.com <http://www.kingdombio.com>,
[email protected] <mailto:[email protected]>
_______________________________________________
Digestion mailing list
to Send a Message to the list, use the email address
[email protected]
to UNSUBSCRIBE or Change your List Settings use the web page
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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/
