Patent GB-410103-A (GB)
Title: Improvements in process for production of lubricating oil
IPC: C10G21/00
Filed: 1932-08-04
Abstract: Petroleum oil is freed from asphalt and separated into fractions having respectively high and low viscosity indices by dissolving the oil in a solvent in which asphalt is insoluble, separating the solution, treating it or the solvent-freed extract with a selective solvent for non-paraffinoids, separating the fractions, and <PICT:0410103/III/1> alcohol, ether, acetone, alcohol-ether, and light petroleum fractions, e.g. naphtha, casinghead gasolene, and fractions normally vapour at ordinary temperature and pressure; the ones preferred are obtained by the rectification of gasolene; one is composed of about 72 per cent of propane with about 38 per cent of isobutane, ethane, and normal butane; the other contains 40--50 per cent of ethane.  Selective solvents specified are aniline, methyl formate, liquid sulphur dioxide, acetone-benzol, and possibly acetone alone.  For example, a residual oil at 200 DEG  F. in tank 1 is pumped through pipe 4 where it meets the above-mentioned propane-containing fraction from pipe 14 and tank 11; the mixture is cooled to about 120 DEG  F. in tank 5 by allowing some of the solvent to evaporate, and passed to agitator 16 and decanter 18 from which the asphalt is withdrawn through valve 19 and pipe 21 to a heater 22, pipe 23, separator 24, and storage tank 27.  The solution of oil is passed from decanter 18 through pipe 35 to a chiller 36 in which the wax is precipitated by temperature reduction effected by allowing part of the solvent to evaporate, and then through pipe 41 to a centrifuge, filter, or cold settler 43 to remove the wax.  The dewaxed oil is led by pipe 44 to an evaporator 70 to remove the solvent through valve 71, compressor 73, and pipes 72, 111, and 38<1> to condenser 9, pipe 10, and p  storage tank 11.  The oil is withdrawn through pipe 75<1> and pump 77, and forced through a cooler 76, pipe 78, to an extractor 104 in which it meets descending liquid sulphur dioxide introduced by pipe 81<1> from a storage tank 79.  The raffinate passes removing the solvents.  The asphalt-free solution of oil may be treated with sulphuric acid and clay and be cooled to separate wax.  Specified solvents not dissolving asphalt are through pipe 84 to a chamber 85 in which sulphur dioxide settles out, then through pipe 87 to a heater 88 in which remaining sulphur dioxide is evaporated off, and afterwards through pipe 92, pump 114, to pipe 115 where it is dissolved in solvent conducted from tank 11 through valve 117, pump 118, and pipe 120.  The solution is agitated with sulphuric acid from a pipe 47<1> and tank 45, is passed into a chamber 51 where the sludge settles out, and then through pipe 52, a clay tower 125, an evaporator 119 to remove solvent, and a pipe 108 to a storage tank 93.  The solvent vapours from the various evaporators and asphalt and sludge recovery plants are conducted to suitable compressors and condensers and returned to the appropriate storage tanks, scrubbing with caustic soda being interposed where necessary.  Specifications 156,123, 234,564, [both in Class 91], and 355,294 are referred to.