Cellulose and maple sawdust have been pyrolyzed by different workers in two different reactors (a fluid bed and a transport reactor) in separate laboratories. The Avicel cellulose sample used by both groups was from the same batch, while the maple was different samples of the same species. Fast pyrolysis product yields were compared at a constant vapor residence time of 500 ms over a temperature range of 450-900 °C and were found to be in very good agreement. It is proposed that if particle heat-up time to 500 °C, for any reactor, is significantly less than particle residence time, or if particle weight loss is less than 10% before the particle temperature reaches 450 °C, then the temperature of the reactor will be the only variable determining the yields of char, oil, and gases for a given feed material and a given gas residence time. The implications of the results in terms of product yields and possible pyrolysis mechanisms are discussed. The oil yield as temperature increases can be described adequately by a simple kinetic model.

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The individual phase holdups in two (liquid‐air, liquid‐solids) and three (liquid‐air‐solids) phase fluidized beds have been measured over a wide range of liquid and gas velocities. Ex‐periments were canied out in a large two‐dimensional bed. Three solids were used ranging in size from 1 to 6 mm. The effect of viscosity (1‐70 cp) was determined using solutions of sugar and carboxymethyl cellulose of different concentrations. Various acetone‐water mixtures were employed to examine the effect of surface tension in the range 40‐73 dyne/cm. Beds of particles having a minimum fluidizing velocity in the liquid of less than 1.28 cm/sec were found to initially contract upon the injection of gas. In contrast, beds of particles having minimum fluidizing velocities exceeding tins value were found to expand.