522.    ----------------.  [CHEMICAL INDUSTRIES.] New CO-H₂ Converter Provides Better Temperature Control.  Vol. 60, 1947, pp. 232-233.

                 Close control of the reaction temperature in the newest Bureau of Mines Fischer-Tropsch converter is achieved internally by vaporizing a hydrocarbon oil from the catalyst surface, instead of by means of heat exchangers alone, as in German practice, or by a fluidized fixed catalyst bed with a heat exchanger, as is proposed in the commercial installations under construction in the United States.  In operation, a fraction of the liquid reaction product (boiling 110°-125°) is passed in parallel flow, along with the synthesis gas, through the column of pelleted Co catalyst at 100-150 p.s.i. and at a space velocity of about 1,000 lb. per m.³ of catalyst per day.  As heat is liberated by the reaction, vaporization of the injected liquid holds the temperature of the catalyst at the desired point, about 200°.  In one continuous run of over 600 hr., no appreciable loss in catalyst activity was experienced.  The method has another advantage in the removal of the high-melting waxes that have always blinded the surface of the Co catalysts after a short period of operation.  It is estimated that an internally cooled unit should cost about the same as the fluid catalyst unit per bbl. of hydrocarbon product per day.  Furthermore, it provides a more flexible operation.