Synthetic Fuels by Gasification (Reed, 2005) [WGT05300]

Dr. Thomas B. Reed wrote on his Biomass Energy Foundation website:

Gasification is used to make synthetic fuels and chemicals such as methanol, ammonia, diesel fuel and even (with more difficulty) gasoline. It is difficult to imagine our current civilization continuing without them.

In 1980 we built a high pressure biomass oxygen gasifier at SERI/NREL (now the National Renewable Energy Lab). Eventually that became the “Syngas, Inc.” gasifier, operated on oxygen at 25 tons/d and on air at 75 t/d. [See Fundamentals, Development, and Scale-Up of the Air-Oxygen Stratified Downdraft Gasifier by T. Reed, M. Graboski and B. Levie (SERI 1988).]

When fossil fuels are gone or too expensive we can make these necessities from coal and biomass with the following three stages of reactions:

  1. Manufacture of synthesis gas:
                 Biomass (or coal) + O2 ==> CO + H2 (carbon monoxide and hydrogen)

  2. Water gas shift adjusts CO/H2 ratio:
                CO + H2O <==> CO2 + H2

  3. Synthesis with Catalyst
                CO + 2 H2 ==> CH3OH (methanol)
                CO + H2 ==> “(CH2)n” (diesel or gasoline, the Fischer-Tropsch reaction)
                3 H2 + N2 ==> 2 NH3 (ammonia)

Sounds simple, but is usually done commercially in chemical plants making 50 -2000 tons/day.

My specialty since 1974 has been the synthesis of methanol, a superior automotive fuel, from biomass. (Methanol is used at the racetrack in preference to gasoline and would replace gasoline with a minimum of changes. Methanol is no better than ethanol as a fuel, but would cost 1/4 as much to make and can be made from biomass, waste, coal, natural gas, and oil (not from corn!). See the article from Science on methanol that changed my career from material scientist at MIT in 1973 to Fuel scientist today.