GB580124A - Improvements in and relating to the refining of benzole - Google Patents

Abstract

<PICT:0580124/III/1> Benzole is refined, to remove sulphur compounds and light hydrocarbons, by passing a mixture of crude benzole vapour and steam from a packed column to a reflux condenser whose uncondensed vapour outlet is maintained at a temperature of 38 DEG to 40 DEG C., returning the reflux to the column, and withdrawing refined benzole from the base of the column. In Fig. 1 crude benzole is fed from tank 3 to the top of packed column 1 provided at 2 with downwardly and inwardly projecting flanges; and live steam is introduced near the base of the column through pipe 5. The vapours from the head of the column are passed to a reflux condenser 10, the uncondensed vapour outlet of which is kept at 38 DEG to 40 DEG C., and the condensate is returned to the column through pipe 11, while the uncondensed vapours, which comprise the impurities, are passed on to condenser 12, and removed from the system either as liquid (CS2) or gas (H2S, HCN). Refined benzole and water are withdrawn from the base of the column, the water is separated in separator 7, and the refined benzole cooled in cooler 8. In an alternative method of operation, a mixture of crude benzole vapour and steam, obtained for example by steam treatment of benzolated stripping oil with or without fractionation of the mixture of benzole vapour and steam, is passed into the lower part of the packed column. An auxiliary condenser may be incorporated at an intermediate point in the column; this is to reduce overloading on the condenser which is to be run at 40 DEG C. A thermostat may be provided, in the offtake from the reflux condenser, to control the steam supply to the base of the column if the rate of benzole input is constant, or the benzole input if the rate of steam supply is constant. Specifications 430,989 and 443,094 are referred to.