Dear All, After sending the mail I have second thoughts about the exact air:fuel mixture required in the primary mixing tube - I wonder if my memory is failing me will confirm the same in a few hours (8-10.5, air : 1, gas). Anyway the burner opening area to the mixing tube dia should obviously be in the ratio of 1:1.5 - 1:2.5 depending upon the pressure drop expected. I will give these numbers shortly best wishes chanakya
Dear Mike Barnet The critical needs seem to be very simple and these we were taught early and they are I suppose this much Whatever be your pressure or flow, the primary air to gas stoichiometric ratio is 8-10.5:1 (air + biogas for pirmary air mixing), mixing tube length about 10-15cm at 100-150mm water pressure. At the top, the gas-air mixtures need to be brought to the burning surface - the openings are usually 4-6mm wide for stable high temperature colorless flame. At the right air to fuel mix and achieving highest combustion temperatures (1050 celcius) - the flame will be barely stable and will emerge about 5mm above the burner surface and will usually emit a short hissing sound. At a higher air to fuel ratio the flame head becomes unstable. Gas consumption at this stage would be about 400L/h giving an equivalence of about 2kW of thermal efficiency around 55% (heat transfer efficiency) for a flat vessel or receiving body For mantle lamps a small deviation is suggested when working under normal gas pressure 100-150mm water pressure). First, reduce the mantle's combustion surface to one third of what is usually available for a kerosene usage. That is tie the mantle such that only a third of the area hangs down the rest is on the ceramic support above. You should now be able to support a flow of about 125L/h and yet have the mantle glowing uniformly round. If you do not reduce the combustion area (tie the mantle to allow only a third of it to glow) the glowing area will not be uniform and will keep moving around. A burner will consume a third of the gas used in conventional biogas burners - 4cft/hr (the original rating) about 125L/hr. I guess you can now succeed without much of a problem best wishes chanakya -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. _______________________________________________ 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 http://lists.bioenergylists.org/mailman/listinfo/digestion_lists.bioenergylists.org 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/
