GB456637A - Control of catalytic operations - Google Patents

Abstract

In effecting reactions in fluids by means of a catalyst which progressively loses its activity during the reaction, the physical conditions such as temperature, pressure, space velocity are progressively modified so as to compensate for the deterioration of the catalyst and maintain a substantially constant degree of conversion. The conditions may be modified either continuously or in stages. Temperature increase may be effected by feeding the reactants at a temperature higher than that of the catalyst. In an example relating to the polymerization of propylene, butylene, &c. to produce hydrocarbons in the gasoline range, the temperature (600--720 DEG F.) and pressure (130 lb.) remain constant and the duration of contact is increased from 80 seconds to 160, 240, and finally 320 seconds. In other examples relating to the conversion of gas oil into gasoline hydrocarbons, the temperature, pressure, or duration of contact or any combination of these may be increased. Specifications 416,025 and 449,050, [both in Group III], are referred to.ALSO:In effecting reactions in fluids by means of a catalyst which progressively loses its activity during the reaction, the physical conditions such as temperature, pressure, space velocity are progressively modified so as to compensate for the deterioration of the catalyst and maintain a substantially constant degree of conversion. The conditions may be modified either continuously or in stages. Increase in temperature may be effected by passing in the reactants at a temperature above that of the catalyst so that heat accumulates in the latter. In an example relating to the conversion of gas oil into hydrocarbons in the gasoline range the reaction commences at 775 DEG F., and by admitting the reactants at 860 DEG C., the temperature is gradually raised to 835 DEG F., after which heat from an outside source may be applied to raise it to 850 DEG F. Alternatively the temperature may be kept constant and the pressure raised from atmospheric to 125 lb. per sq. in., or the rate of flow may be reduced by 5--50 per cent. In another example relating to the polymerization of propylene, butylene, &c., to produce hydrocarbons in the gasoline range the temperature (600--720 DEG F.) and pressure (130 lb.) are maintained constant and the duration of contact is increased from 80 seconds to 160, 240, and finally 320 seconds. Specifications 416,025 and 449,050 are referred to.