Are there plans/diagrams available for building an eko/econo style gasifier?

[hdivr]

I've been tossing around the idea of building either a seton type or downdraft gasifier wood boiler. Not in a big hurry, just a nice summer project. Are there any companies/individuals who sell plans on building a homemade gasifier? I've researched and don't see any available. I have seen nice vids on youtube, etc showing operation.

Although it seems you can find OWB plans all over the net. It would be nice to learn from others trials and errors.....especially with regards to nozzle size and size of secondary air inlets. Does one just build a two chamber firebox with refractory plate in the middle and just tweak the blower speed until the flame jet is optimal?

Or is this information super secret/proprietary info?

 

[Nofossil]

It's not super-secret or proprietary, but there seems to be a surprising amount of complexity that's not apparent when you look at these. My brother built one based on the geometry of the EKO 25, and its' worked pretty well. Other attempts have met with varying degrees of success. I don't know all of the factors that are critical to proper operation, but here are a few that I suspect are in that list:

- Air velocity through the nozzle
- Primary / secondary air ratio
- Primary airflow to nozzle cross section ratio
- Nozzle length
- Ratio of total air to generated wood gas (this one needs to be right around 1.6 times stoichiometric - about 22 cfm for the EKO 25, if I remember right)
- secondary chamber volume to airflow ratio (this determines 'dwell time' - the time available to complete combustion before hitting the HX tubes)

My brother copied as much of this as possible, and provided lots of adjustments for tweaking afterwards.