[Terrapreta] range fuels

[Sean K. Barry]

Hi Kevin, Kelpie,

I don't know exactly what Range Fuels is doing to make ethanol?  But I do know the basics of "thermal conversion process" which could do this.  If an "oxygen-blown" gasifier (pyrolysis reactor) is used (versus an "air-blown" gasifier), then the generated gas is called "synthesis gas" (H2, CO, CO2, CH4, H2O, trace O2 and others).  With an "air-blown" gasifier, the resulting gas is called "producer gas" (N2, H2, CO, CO2, CH4, H2O, trace O2 and others).  These gas mixtures are very similar, "producer gas" being like "synthesis gas" diluted with Nitrogen gas-N2.

Air contains ~78% Nitrogen gas-N2 and ~19% Oxygen gas-O2.  Since N2 is chemically inert at pyrolysis temperatures, then the N2 passes through the reactor and dilutes the product gases of the reaction.  When pure oxygen is used instead of air as the oxidant, then the resulting "synthesis gas" has higher concentrations of the fuel gases Hydrogen gas-H2, and Carbon monoxide-CO, and actually a lower concentration of Methane-CH4.

Back during World War II, two Swedish scientists, Dr. Fischer and Dr. Tropsch developed a method to convert "synthesis gas" into liquid fuels, like Methanol and Ethanol.  The German army harvest wood from the Black Forest and made liquid fuels to supply its vehicles using the process.  This was done in the back of truck! In a Fischer-Tropsch reaction "synthesis gas" is heated and injected into a pressurized chamber that has a metal surface (something like an Iron-Cobalt alloy) which "catalyzes" this gas-to-liquid conversion.

There is a company, Rentech, which operates in California, Colorado, Montana, and Iowa that is using an FT reaction to make synthetic diesel (a liquid fuel) from "synthesis gas" that is got from gasification of western brown coal.   I would say, too, that this is the most like process that Range Fuels is using to convert lignin and cellulose from wood into ethanol.

It is worth noting that when wood is pyrolyzed with pure oxygen, that the process can be continued either until only ash is left or the reactants can be moved out and new feedstock put in.  The primary soild reactant is CHARCOAL!  So, pyrolysis and gasification of wood/cellulose/liginin can have the co-products of gaseous fuels, liquid fuels, sensible heat, electricity, and charcoal.

Regards,

SKB


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