Abstract:
A downdraft gasifier fuelled with charcoal was used to
generate producer gas for the purpose of this study. The gasifier
had dimension of 45 cm. in diameter and 90 em. in height. At the
throat section, the diameter was 20 cm, The gas cleaning units
consisted of a cyclone, a filter tank, and a standard filter box
connected to the gasifier. The producer gas flowing from the
bottom of the gasifier first passed through the cyclone where
most of the large particles were collected then passed through a
heat exchanger to reduce the gas temperature. The gas then passed
through the filter tank. At this stage, fine particles were
collected. Different types of filtering materials were used.
These included cotton cloth, cotton, fiber glass, nylon, and rice
husk. Finally the gas was forced through a submicron particles
standard filter. The standard filter was capable of collecting
Particles as small as 0.1 um. The performance of each cleaning
unit was then determined. The results indicated that particles
size between 10-325 um were collected in the cyclone with 85%
efficiency. Among different types of filtering media rice husk
gave the highest efficiency (an average of 98%) and least pressure
drop (0.5-1.5 cm. water). Nylon gave a lower efficiency (average
of 95%) and the highest pressure drop of 1.7-7.5 cm. water.
Particle sizes being collected on the filtering medium (including
the standard filter) varied between 0.5 to 35 um.