[Gasification] Any experience with Stak Properties 10K gasifier?

[Robert Kana]

Dear Bill, Kevin and all,
Thanks for the valuable information. As you put it very clearly, 
successful gasification starts with a " Good prepared fuel" and 
continues with well built gasifier.
For pellets we don't have so much experience, but we know they are made 
with pressure and the heat caused by friction. On the other hand, 
briquettes made with hydraulic press or screw press. Material has to be 
dried to 10-15 % moisture hydraulic systems have pressure 1300-1700 
kg/cm2, screw systems double that pressure up to 3000 kg/cm2 depending 
on screw design... On screw systems, forming cylinder is also heated 
around 300 degrees Celsius.  I can break the concrete walls with the 
briquettes we make, ( Sometimes the hole in the briquette gets clogged, 
with pressure and heat the gas accumulated inside the forming cylinder  
blows up sending the front piece of the briquette to concrete wall. In 
front of every machine, we have holes in the concrete wall... ). Density 
of 1 m3 of briquettes are more than 1300 kg.
Briquettes are much more uniform but harder to make compare to the 
pellets. We have done gasification with briquettes and also briquette 
charcoal. Both resulted in very clean gas, specially the briquette 
charcoal. With the charcoal, must be careful about the heat in the 
reactor. It goes over 1200 C very fast and makes clingers. They are 
perfect for steam gasification since the briquette charcoal has over 
7000 Kcal energy.
For the price factor, briquettes are exported at $ 175.00 per ton, 
briquette charcoal is $ 500.00 per ton. It is better to use briquettes 
for gasification. We have made briquettes using saw dust ( from very 
light wood to hardest wood dust available) and rice husk. Rise husk is 
very abrasive and eats the screws very fast.
I guess for all the people who lives in the woods, or near the woods, it 
would be better to use the wood chips or chunks. As my experience, 
uniformity of size is not as important as the dryness of the fuel 
prepared. We have gasified rice husk and up to 4 x 4 x 5 inches, size 
wood chunks (in a smaller size gasifier with only 15 cm throat I still 
can't figure out how they go through the reactor, but they do...) for 
thermal purposes, results were always good. If your fuel is dried, you 
will get better quality gas to running engines. Gasifier can be pushed 
to get more gas for thermal purposes, but to use the gas in the engine, 
you must really adjust and stay in certain parameters.
As Bill said, every gasifier is different. You must play and experience 
with your own gasifier. First get the gas and quantity you need. Than 
you can play with the reactor design to get a cleaner gas.
Thanks to everybody sharing their experience and knowledge as much as 
possible. Every time I built a gasifier and get good quality gas, I 
thank to many people on and off the list, from my hearth to give me the 
knowledge and courage to pursue gasification.
Best wishes to you all...
Robert Kana, Biomass Indonesia