Seethalakshmi Achi College For Women, Pallathur

Bio Gas Project - Feb 2011

By SAC Foundation

The Bag Digester was the absolute low cost model that was sourced from the net. However, when assembling, the following problems came to light forcing it's abandonment in favour of the Drum Digester:

  1. The material best suited would have been a thick HDPE Cylinder of the sort used by bag manufacturers.
  2. This would have been available at Chennai, but Madurai was hopeless.
  3. Assumed we could use a thick sheet with 3 layers and bought the best available
  4. This posed problems of pasting since there was no reliable Plastic-Plastic glue / epoxy
  5. Managed to paste the entire length by criss crossing with the pop corn sealer
  6. The 5 feet original turned out to be very small after putting in the inlet & outlet pipes
  7. Hence made a 20 feet bag with a single layer
  8. Upon completion, suspicions arose about it's strength and whether it would withstand the elements and the monkeys about town
  9. Moreover, the cost of digging a 25 feet pit would also have been high
  10. Therefore decided to purchase 3 HDPE 200 litre barrels instead
  11. We now have a long good blue plastic sheet in cylindrical form - any takers - can use it as a table cover - or possibly as a gas scrubber later!

Monkeys are already on the job and now have to provide a shelter. Just tooled up from Chennai -
Plastic welder consisting of a hot air gun and hdpe welding rods and other accessories to fabricate the Scrubber (Water + Activated Carbon + Steel wool) and other fittings. It seems that we have to use HDPE pipes instead of the PVC now used for the plastic welding to work. Will cross that bridge later.

Storage of the gas will be in Tire Tubes currently hung on a tree branch linked to the Digesters using a tube.

Update 2011-03-14

Rejigged the whole set of digesters and obtained a nice blue flame. It is now based on a new fully vertical design.

Update 2011-03-22

Reconstructed Vertical Digesters are now in place and the Truck Tyre Tubes get filled overnight.

The gas collected was tested out in an improvised burner (less air mixture since low pressure) and sweet payasam dish was cooked on it and offered to Lord Varasiddhi Vinayagar on the premises.

Page will be updated as work progresses.

References: 1, 2 (pdf), 3 (pdf)

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