Mild hydrofining of light virgin naphthas

摘要

Light virgin naphthas (boiling range C1 to 430 DEG F.) are desulphurized by contact at 450 DEG to 750 DEG F. with not more than 30 SCF/Bbl. of hydrogen in the presence of a hydrofining catalyst, the hydrogen consumption rate being below 25 SCF/Bbl. The pressure may be 50 to 800 p.s.i.g. and the feed rate 1 to 10 V/V/Hr. The feed may be unstabilized or stabilized by removal of C3 and lighter fractions. The hydrogen may be pure hydrogen or it may contain up to 60 degrees of inert diluents and may be derived from other refinery processes, e.g. hydroforming. H2, H2S and C3- hydrocarbons may be removed from the product in a flash drum. Residual traces of H2S may be removed by caustic washing, e.g. with 2-5 wt. per cent of S0Be caustic alkali. Preheating of the hydrogen is not necessary but it may be mixed with the feed before the latter is preheated. Hydrofining catalysts mentioned are 5 to 15 wt. per cent molybdenum oxide and mixtures of cobalt oxides (2-6 wt. per cent) and molybdenum oxides (6-15 wt. per cent), both an activated alumina. They may be regenerated at 900-1100 DEG F. with an oxygen-containing gas. In an example a C1-300 DEG F. virgin naphtha was treated at 600 DEG F., 550 DEG F. and 500 DEG F. with 30 SCF of hydrogen per barrel of feed at 225 p.s.i.g. and a feed rate of 4 V/V/Hr. using 10-14 mesh cobalt molybdate on alumina. The hydrogen consumption was 12-15 SCF/bbl.