Patent GB-1057911-A (GB)
Title: Separation process
IPC: C07C45/78
Filed: 1964-04-10
Abstract: Organic material is separated from liquid or solid mixtures by contacting the mixture with an inert gas maintained at a pressure greater than the critical pressure of the gas and at a temperature between the critical temperature and about 100 DEG  C. above it; at least part of the organic material vaporizes into the gas, and when the loaded gas is submitted to decrease in pressure and/or increase in temperature, the organic material is precipitated from the gas in liquid or solid form.  In an example, petroleum is mixed with ethylene at a temperature of 20 DEG  C., the pressure in the mixer being maintained at 120 kgs./sq. cm.  The mixture flows into a separator where the non-absorbed oil is separated <PICT:1057911/C4-C5/1> from the loaded gas stream.  The loaded gas is then conducted through four separators connected in series by lines having pressure-reducing valves, the pressures in the four separators being maintained at 110, 95, 70 and 40 kgs./sq. cm., respectively. Four fractions, amounting to 50% of the crude oil, are precipitated in these four separators, and the fractions, when distilled, are found to have very different boiling ranges.  The ethylene leaving the last separator is repressurized, and recirculated to the mixer. Instead of precipitating the petroleum fractions from the loaded gas by stepwise decrease of pressure, the loaded gas may be submitted to stepwise increase in temperature to 50 DEG , 80 DEG , 110 DEG  and 140 DEG  C. in order to release the fractions.  A fractional separation process may be carried out, similarly to rectification, in a tray column 138.  The starting material, e.g. a hydrocarbon fraction, is introduced through line 131 into saturator 132, which is also supplied with compressed gas, e.g. ethylene, through line 133. The mixture flows into separator 135 where the non-absorbed part of the starting-material is separated, and collects in tank VII. The loaded gas flows through line 137 into the lower part of the column where it rises and undergoes material-exchange with the downwardly-flowing reflux.  The column is operated at 20 DEG  C.  The gas leaving the top of the column passes through pressure-reducing valve 139, whereupon the most volatile components of the starting-material separate from the gas in the liquid state.  Part of this liquid is pumped back to the top of the column as reflux and the remainder is collected in tank I.  The gas is then recompressed and recirculated to the saturator 132.  In the embodiment shown, four gaseous sidestreams are withdrawn from the column, and each is passed through a heat exchanger 143 to a separator 144 where it is raised to 100 DEG  C.  Four liquid fractions are thereby obtained, which are collected in tanks II to V.  The gas separated from the liquid in each separator 144 is returned to the column; and if desired part of the liquid may also be returned.  The liquid flowing out of the base of the column is also passed to a separator maintained at 100 DEG C.; the liquid from which is collected in tank VI while the gas is returned to the column via heat exchanger 143.  The separation of naphthalene from methylene blue is referred to in Example 31.  The separation of naphthalene from anthracene is referred to in Example 32.  The separation of 1-phenyl-decane from 1-phenyltetradecane is referred to in Example 40.  The separation of n-dodecane from n-tetradecane is referred to in Example 34. Examples 33, 35, 36, 37, 38, 39, 49, 50, 53, 55, 57, 58 and 59 relate to the separation of specified saturated and unsaturated aliphatic hydrocarbons. Mixtures containing paraffin oil are also separated.ALSO:A mixture of higher aluminium alcoholates, e.g. those having an average of 12 carbon atoms per molecule, produced by the oxidation of higher aluminium trialkyls which have been prepared by treating lower aluminium trialkyls with ethylene in "the growth reaction," is purified by distilling off olefines and then contacting the mixed alcoholates with ethylene or carbon dioxide gas under supercritical conditions whereby the by-product impurities are vaporized into the gas.  If ethylene is employed, it may be passed to the mixture at a temperature of 75 DEG  C. and a pressure of 200 atm.  The aluminium alcoholate mixture may then be separated into alcoholates of different alcohol chain-lengths by treatment with ammonia under supercritical conditions (e.g. 170 DEG  C. and 350 atm.).  The individual fractions may be separated from the gas stream by stepwise depressurisation and/or by submitting it to stepwise increase of temperature.