172.    BECK, R. A.  Evaluation of Fluid Catalyst – Development of Laboratory-Scale Units.  Ind. Eng. Chem., vol. 41, No. 6, 1949, pp. 1242-1243.

                  Two types of laboratory scale units for evaluation of fluidized catalyst have been developed.  A mechanically stirred unit with helically finned rotor makes it possible to simulate fluidization independently of the gas velocity below 1 ft. per sec.  A steel-stirred reactor is used in research where great flexibility in regard to reactant flow rates is desired.  A baffled nonstirred unit is less subject to mechanical difficulties than the stirred type.  Both types have proved to be effective laboratory units for the testing of small batches of experimental catalysts with moderate amounts of charge gases.  For example, the use of a superficial linear velocity of 1 ft. per sec. in the 0.75-in. baffled reactor at 400 p.s.i.g. and 600° F., requires approximately 140 standard cu. ft. per hr. of total charge gas as contrasted with over 1,000 required for the open 2-in. reactor originally cited.  With the stirred reactor the feed rate can be reduced to any desired level without decreasing the effectiveness of catalyst fluidization.