wood boiler gasifier plans

No blueprints that I know of, but a lot of people have explored this and some have even done it. Use the search bar above and you will find all sorts of things. In particularly look up garnification and see what he did. Once you have looked over the various threads, post some specific questions and I am sure you will get all sorts of opinions...

Note: It helps to limit your search just to the boiler room...

Also check out nofossil's website. His brother built one based on the eko design... http://server.cedarlakedesign.com/pictures/buzz/Nofossil/

If you search enough, you'll find my take on this:

Gasifiers look very simple, but there's a lot of technology hidden in that simplicity. If you build your own, take some time to study existing models and think hard about how they're made and WHY they're made that way. A few critical design parameters that I'm aware of:

1) Primary airflow related to wood surface area, firebox volume, and nozzle cross-section
2) Secondary airflow related to primary airflow
3) Secondary combustion chamber volume and baffle design
4) Primary chamber sealing - wood gas is evil smelling and VERY toxic, and the primary chamber is usually under pressure.

Air introduction into the primary chamber is critical. You want to generate a specific volume of wood gas that has a certain oxygen level. The oxygen level must be low enough so that it doesn't burn in the primary chamber, and the flammable components must rich enough and hot enough so that it will burn happily when secondary air is introduced. You want to introduce enough secondary air to get complete combustion without wasting energy by pushing excess air up the flue. The conventional wisdom is that you want about 1.6 x stoichiometric, which works out to about 23 CFM at 80,000 BTU/hr for my EKO if I remember right.

The nozzle cross section has to create a high enough velocity to keep the flame below the nozzle, but not high enough to blow out the flame at lower temperatures.

Gasifiers present a really hostile environment for materials. I've created a lot of expensive gravel in experimenting with refractory materials, and others have horror stories about what happens to the materials inside the boiler. My brother has a big crack in the cast firebox floor, for instance.

That having been said, I think gasifier design is an area where there are still improvements to be made to design, materials, and controls. My goal here is not to discourage you, but to make sure that you're prepared for the challenges involved. Best of luck to you.