The auger type of pyrolyzer has been identified as especially appealing for its potential to reduce operating costs associated with bio-oil production. This design may also be well suited for small, portable pyrolysis systems in a highly distributed or decentralized biomass processing scheme. The operating principle of this design is that biomass is continuously pyrolyzed by being brought into direct contact with a bulk solid heat transfer medium referred to as a "heat carrier." The heat carrier material, such as sand or steel shot, is heated independently before being metered into the reactor. On a gravimetric basis, thermodynamic calculations suggest a heat carrier feed rate 20 times the biomass feed rate. Two intermeshing, co-rotating linch augers quickly combine biomass and heat carrier in a shallow bed to effec­tively carry out the pyrolysis reactions. This mechanical mixing process, though not well understood, appears to be the essence of this alternative pyrolyzer design. Volatile vapors and aerosols exit at various ports, while char is transported axially through the 20 inch long reactor section and stored in a canister with the heat carrier (Brown, 2009).