PATENT

3723.  SWEETSER, S.B., AND SMITH, L.B. (Standard Oil Development Co.).  Heat Control in an Exothermic Reaction.  United States Patent 2,468,521, Apr. 26, 1949; appl. filed Apr. 17, 1946, Serial No. 662,906; 8 claims (Cl. 260-449.6.).  Chem. Abs., vol. 43, 1949, p. 4908.

Catalyst of particle size 150-250 m is mixed with an inert material, such as alumina, fullers earth, or silica gel, of 1-50 m particle size.  The proportion of inert to catalyst is about 20-200% by weight of the catalyst.  The proportion is lower in the case of nonsupported-type catalyst of relatively high density.  The inert particles continuously pass out of the reaction zone with the product.  They are separated and cooled with H₂O or a vaporizable hydrocarbon, such as a light naptha fraction, separated from the vapor, and returned to the reactor.  Indirect heat exchange may also be used, such as a fluid-type hydrocarbon synthesis reactor reactor containing 100 cu. Ft. of Fe catalyst, d. 150 lb. per cu. ft., utilize 45,000 cu. ft. per hr. of a synthesis gas containing 45% CO.  With 95% conversion of the CO, the heat liberated amounts to 2,640,000 B.t.u per hr.  When clay with a specific heat of 0.25 is used as the diluent for the catalyst, it is necessary to circulate 34,000 lb. per hr. of clay between temperatures of 600° F. in the reactor and 250° F. in the cooler for the inert material to transfer all of the heat of reaction.  If the Fe catalyst is mixed with 25% by weight of the clay, the desired cooling is obtained by circulation of the clay approximately 9 times per hr. in a complete cycle through the cooling system.  3 United States patents cited.