Method for producing aromatic hydrocarbons

A method for producing aromatic hydrocarbons from light hydrocarbons by catalytic cyclization, which comprises supplying a light hydrocarbon feedstock comprising a saturated hydrocarbon fraction and an unsaturated hydrocarbon fraction, and wherein the weight ratio of said saturated hydrocarbon fraction to said unsaturated hydrocarbon fraction is from 0.43 to 2.33 to a fixed-bed, adiabatic reactor containing a fixed catalyst bed comprised of a zeolite catalyst, to thereby contact the light feedstock with said zeolite catalyst in said fixed-bed, adiabatic reactor and effect a catalytic cyclization reaction of said light hydrocarbon feedstock, said zeolite catalyst being at least one member selected from the group consisting of a substantially fresh zeolite catalyst and a steamed zeolite catalyst, wherein said catalytic cyclization reaction is performed under conditions which satisfy all the following requirements (1), (2), (3) and (4):

• (1) said zeolite catalyst has an initial stage-catalytic activity of 0.2 (sec.sup.-1) or more in terms of the initial stage, first-order reaction rate constant of the decomposition of n-hexane catalyzed by the zeolite catalyst as measured at a temperature of 500.degree. C. under atmospheric pressure;
• (2) the catalyst bed has a temperature in the range of from 450.degree. C. to 650.degree. C.;
• (3) the catalyst bed exhibits a temperature distribution with respect to the distance from an inlet of the catalyst bed to an outlet of the catalyst bed, wherein said temperature distribution has at least one maximum temperature value between the inlet and the outlet of the catalyst bed;
• and
• (4) the temperature of the outlet of the catalyst bed is in the range of .+-.40.degree. C. relative to the temperature of the inlet of the catalyst bed.