On the basis of previous work in hydrofining crude benzole with pure hydrogen

further study was made of the utilization of low concentration hydrogen as a raw treating gas. Successful precaution was employed to overcome coking trouble by means of pretreatment of the crude benzole and raw gas

effect of which was discussed. The influence of process variables on Br. No. and S reduction in the product oil was then investigated; the differences in reactivity of crude benzole from several sources were also observed. A set of compromised operating conditions for hydrofining crude benzole from a certain plant to obtain a product of Br. No.<0.5 and S<0.01% was suggested. The result was verified in a larger equipment with 200ml. catalyst volume. The activity of the catalyst could be maintained through the 200-hr

run. Material balance was obtained with a liquid yield of 98.7%. The product oil of Br. No.0.3 and S 0.002% after fraction nation gave benzene of synthetic grade with a 99.1% recovery. Additional experiments showed that the type 402 catalyst retained its good activity after regeneration and prolonged heat treatment at elevated temperature. Development work with pure hydrogen was carried out in a pilot plant of 9-liter catalyst volume. Under a pressure of 20 kg/cm2

380℃

L. H. S. V. 2.0

a product of Br. No. 0.4

S 0.01% was obtained

with a liquid yield of 98.2%. Benzene

fractionated out

was of synthetic grade. The activity of the catalyst

prepared with industrial grade carrier and on an enlarged scale

remained unchanged during this 150 hr. run

and its good regeneration ability and thermal stability were also confirmed. Further demonstration plant work was recommanded to collect design data and to gain additional operating experience.