Notes from Windward: #70


Covering the GEK

Opalyn re-purposes materials to keep it dry

     In the old days, hunters had to remember the adage, "Keep your powder dry!" since damp gun powder goes "psssst" instead of BANG! In the gasification of woody biomass, the moisture content of the fuel plays a critical role in how the gasifier performs and the energy content of the gas it generates.

     So, in order to keep our GEK and its fuel dry, it made sense to create a shelter to fit. I took a pipe structure we had that's similar to what's commonly known as a "Costco Garage" and altered it to fit some 8' corrugated metal roofing that Walt found in Deep Storage. I attached the roofing to the framework with screws set in holes that I pre-drilled. Here's a pic of the structure with 2' legs in place to make working on the roofing easier.

screwing on the corrugated roofing

     After the screws and old holes are caulked, the crew helped raise the structure. We took out the short legs and inserted 6” poles. We also moved the structure over the GEK and weighted it to several concrete pillars to keep it from becoming a sail and flying away.

the "new" GEK shed with wind weights

     To celebrate the GEK's new cosy home, I started it up and lit off the flare while I waited for the system to heat up. Soon, the internal thermocouple that's near the reduction bell showed a temp of 515°C. That's hot enough to produce a clean, powerful fuel gas suitable for use in an internal combustion engine.

checking the GEK's internal temperature

     Now that the GEK has had several successful runs producing clean (i.e. tar free) gas, we were curious to see how our diesel tractor would perform using the fuel.

feeding wood gas into the Fordson tractor


     There are two kinds of internal combustion engines in general use: gas and diesel. The fuel in a gasoline engine is ignited by a spark, but the fuel in a diesel engine is ignited by hot air. When air is compressed, it gets hot; compress it enough, and the air becomes hot enough to ignite diesel fuel.

     Wood gas is combustible, but compression alone won't ignite it‒there has to be a spark or something else to ignite the wood gas, so it can't serve as the sole fuel in a diesel engine. What it possible is for wood gas to supply the majority of a diesel engine's fuel so long as there's enough diesel injected to act as an igniter for the wood gas.

      In practice, it's possible to have wood gas supply as much as 80% of a diesel engine's fuel needs. That's not as good as supplying 100% of an engine's fuel needs‒as is possible with a spark ignited engine‒but it's a way to make a gallon of diesel fuel go five times as far as it would if you were using diesel fuel alone.

Notes From Windward - Index - Vol. 70