Patent GB-256922-A (GB)
Title: Oxidized products, processes of making same, and apparatus therefor
IPC: C07C27/10
Filed: 1926-03-02
Abstract: 256,922. Penniman, W. B. D. Aug. 13, 1925, [Convention date]. Mineral and tar oils; oils and spirits for burning; paraffin and mineral waxes.-The oxidation of crude petroleum and its distillates, shale oils and tars, waxes, sludges, petroleum residues, asphaltic oils, asphalt, malthas, cracked oils, and residues from cracking stills, wood tar oils and wood tar, peat and lignite distillates, coal tar oils and coal tars, and oils containing powdered coal, coke or peat, sulphur &c. in suspension, by passing air or other oxygen-containing gas through a layer of the material of a depth sufficient substantially to deoxygenate the air &c., is carried out in stages in a series of treatment zones, and under pressure. The products of oxidation include aldehydes, fatty acids, alcohols, ketones, solvents, gums, and substances adapted for use as motor fuels or burning oils. The oxidizing gas may be enriched with oxygen or be diluted with steam, and its point of entry into the oil &c. layer may be varied to promote or retard settlement of suspended solid matter. The process is preferably carried out at a temperature of 600- 900‹ F., though the temperature range may extend from 300-1000‹ F. Catalysts such as aluminium chloride, the oxides of manganese, lead, iron, chromium, vanadium, zinc, copper or calcium may be added, and also neutralizing agents such as quick lime, limestone, or alkali carbonates. The depth of the oil layer under treatment is preferably maintained substantially constant, as by intermittently or continuously feeding fresh oil to, and withdrawing treated oil from, the reaction chambers. Baffles mav be provided in the reaction chamber to impede the passage of air therethrough, to assist the circulation of the oil, or to cause any separated solid material, such as carbon, to be deposited in a desired part of the apparatus. The reaction chambers may be externally heated, or the oil &c. and air &c, may be preheated, and the temperature in the chambers he maintained solely by the heat of reaction. The oxidation and disintegration products of the oil &c. removed by the current of air are condensed with or without pressure, and the deoxygenated air &c. may be passed through silica gel or absorbent carbon to extract residual vapours. As shown in Fig. 1, the apparatus for carrying out the process may comprise vertical stills 25, 28-30, the first of which is adapted to be heated by a furnace 26, a common condenser line and coil 70, and a receiver 73. Oil is passed from the first still to the other stills in succession by pipes 31-33, and air is supplied to the stills by a pump 35 through a coil 42 which may be heated by a burner 43, a main 36, and distributors 37-40. Each still may be provided in its upper part with a dephlegmator and a heat interchanger, and each still head mav be fitted with a coil 46 connected to live and superheated steam mains 47, 48, so that the temperature of the vapours passing to the condenser may be controlled. Residual material may be withdrawn from the still by pipes 55, and pipe 57 may serve to withdraw partially treated oil from the stills 25 or 28. The temperature maintained in each succeeding still may be 50‹ F. higher than that of the preceding one, and the stills may work under different pressures, though the pressure used is usually 300-400 lbs. The products from each still may be separately collected and treated, and fractional condensation may be used to facilitate separation of the distillates. More than one air supply line may be provided, and the air may be distributed into the oil by a series of radially extending perforated pipes. In an example, a mid-continental gas oil containing one per cent of sulphur was treated. It was preheated to 500‹ F. before the first still was operated, and the temperature during treatment rose to, and was maintained at, 725-750‹ F. Each still was worked under 300 lbs. pressure, and had air supplied to it at the rate of 300 cubic feet per minute. The distillate obtained was run into a wooden tank, and separated, on standing, into an upper water-insoluble layer. an intermediate mixed layer, and a lower layer containing a water solution of organic substances. Any water-soluble constituents in the upper layer were washed out with water. From the upper layer acids, phenols, aldehydes &c. may be removed by agitation with a ten per cent solution of caustic soda; or acids may first be removed by sodium carbonate solution, and aldehydes and phenols then be separated by caustic soda; or aldehydes may first be removed by a concentrated solution of sodium bisulphite, which may be produced from the sulphur dioxide formed during the process, when a sulphur-bearing oil is treated. The material remaining after the treatment with caustic soda may be washed with water, treated with a small amount of sulphuric acid and distilled, the distillates up to 400‹ F., which mav contain up to three per cent of oxygen, being used as a gasoline substitute; or they may be mixed with ordinary gasoline. benzol, acetone, &c. The residues from the distillation may be returned to the stills for further treatment. From the sludge obtained by the treatment with sulphuric acid, alcohols may be recovered by diluting the sludge with water and then steam stilling it. The upper layer may be first purified by passage through fuller's earth, silica gel, or heated bauxites; or it may be redistilled with aluminium chloride; or it may, following the treatment with sodium carbonate or caustic soda, be distilled with five per cent of aniline or with phenol to separate aldehydes. The caustic soda solution from the distillate may be acidified and steam stilled to isolate the volatile fatty acids and phenoloid bodies, which are then separated from each other by sodium carbonate. The lower water-soluble layer of the distillate, containing lower fatty acids, aldehydes, ketones, and alcohols, was subjected to fractional distillation between 20 and 95‹ C. The first two fractions were practically pure acetaldehyde; the remaining fractions were treated with caustic soda and redistilled, whereby a clear liquid of boiling point range 40-85‹ C. was obtained, which may be added to gasoline or kerosene to give it antikick properties, or be used as a solvent for shellac, gums, cellulose esters. &c., or for the extraction of fats or medici. nal principles. The residue from this distillation may be treated with sulphuric acid and steamstil'ed, the gummy residue being either used for making gums or being combined with aniline, hydrazine, or phenol. The oil &c, withdrawn from the still during the process may be treated to recover fatty acids or mav be returned to the still. Before treatment, the oil &c. may be chlorinated, nitrated, sulphated, &c.