[Digestion] flame lifting

[Deepak D. G.]

Dear David,

Thanks for the advice. The issue is very difficult to get proper parts 
and consistent sizing in bali. Every time I buy gas jet the size always 
changes.

I actually get my burners made locally since it is not available locally.
I will try to reduce the gas flow by closing the gas tap bit and will 
update you the result.

What do you mean by pressure control valve?? Please elaborate that

Regards,
Deepak


David Fulford wrote:
> 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
>