US1970796A - Process of treating oil - Google Patents

Description

Aug- 21, 1934. G. A. lallswlalwl-:R 1,970,796

PROCESS OF TREATING OIL Filed Jan. 2l, 1930 INVENTOR ATTORNEY Patented Aug. 21, 1934 PATENT FFICE PROCESS F TREATING OIL Gustav A. Beiswenger, Elizabeth, N. J., assigner to Standard Oil Development Company, a corporation of Delaware Application January 21, 1936, Serial No. 422,255

4 Claims.

'I'his invention relates to a process of treating oils and more particularly to an advantageous combination of distillation and treating steps.

In a way, the present invention may be consid- 5 ered as an improvement over the process disclosed in U. S. Patent application Serial No.

408,966 of A. A. Wells, filed November 22, 1929.

According to the process of the last mentioned application lubricating oils are taken off as side streams, or as bottoms from the distillation equipment, and are submitted while hot to treatment with decolorizing agent such as nely divided clay (acid treated clay-fullers earth). Finished lubricating oils are thus obtained without acid treatment.

The invention Will be fully understood from the following description read in conjunction with the drawing, the single figure of which is a diagrammatic elevation of an apparatus adapted to carry out the invention.

In pipe' still operation the feed stock to be treated is passed through a series of heated tubes into a'fractionating tower in which the distillation takes place, and products are septomary to steam strip the various side streams and the bottom stream, or at least some of these streams, to free them from the light'ends. The strippersconsist, in principle, of small bubble towers with bell cap plates or an equivalent construction. The stream to be stripped is introduced into the stripper above the uppermost plate and leaves the stripper at the bottom thereof after having come in contact with superheated steam passed in countercurrent with the oil stream. The light products in the steam are then returned to the fractionating tower. The stripped products may be of poorer color than desired hence require clay contacting or some 40 other means of decolorization. If the normal procedure of clay contacting is resorted to after the oil has been cooled and removed from the equipment, a considerable fuel and equipment cost is encountered, due to the necessity of 'reheating the oil to relatively high treating temperature.

In my improved method the contacting is carried out in the same stripper utilizing equipment and heat already available. It is only necessary to provide an opening in the steam stripper for the introduction of clay either as obtained, or in the form of a slurry mixed with some oil of the same character as the stream treated. The agitation necessary for the treatment is elected by the steam passing countercurrent to the oil arated according to their boiling point. It is cusstream for the purpose of stripping the same. It will be understood that the treating temperature in my process is predetermined by the temperature of the oil stream passed through the stripper and, therefore, the regulation of the degree of treating must be carried out principally by a careful control of the treating time. The latter may be carried out by increasing or 'decreasing the amount of liquid retained on the bell cap plates, and by regulating the amount of e5 liquid held in the bottom portion of the stripper. The method of this regulation will be obvious to those skilled in the art and Will, therefore, not be described in more detail. Another obvious method of regulating the treating time consists 'm of introducing the slurry of oil and solid treating agent into the stripping column at such a height thereof that the solid treating agent stays in Contact with the oil just for the amount of time required for treating.

In the figure, 1 denotes the feed line; 2 the heater; 3 the fractionating tower; 4 the cooler for the overhead products; 5 a reflex line; 6 and 6 the strippers, two of which are shown by way of illustration; on these strippers 7 and '7' are the lines for taking off the stream from the fractionating tower 3; 8 and 8 are lines for introducing steam; line 9 and 9 are the lines for introducing the slurry of clay and oil; 10 and 10 are the return lines for the steam and stripped vapors; 11 and 11' the lines for removing the mixture of stripped oil and clay from the stripper; 12 and 12 are lters for the separation of the oil from the clay. I

In carrying out the process the charge, such as reduced crude, is fed by means of a pump through the feed line to a heater in which it passes through a series of tubes heated by the combustion gases of the furnace. The oil is heated here tothe required temperature and then discharged into the fractionating tower which may contain bell cap plates, or equivalent fractionating means. The charge is separated here into several fractions such as, for example, gas oil fraction obtained as overhead product, par- 10g aflin distillate, and a cylinder stock fraction obtained as side streams, and a bottoms consisting of asphalt. The distillation and fractionation may be carried out under any pressure such as, for example, under atmospheric pressure or under 105 vacuum. The side stream such as the paran distillate and a cylinder stock shown in the drawing are treated with a slurry of clay and parain oiland cylinder stock respectively, while these streams pass through the strippers 6 and 11o V A 50% reduced Mid-Continent crude oil was submitted to distillation under vacuum in the pipe still described above. The products obtained were: asphalt, cylinder oil'and paraffin` distillate'. Thecylinder oil was treated with 2 lbs/gal. of Filtrol in the stripper allowing a time of contact of about 1 minute. The temperature inthe cylinder oil stripper was: 625 F. at the top and 575 F. at the bottom. The cylinder oil which had a viscosity of 133 sec. Saybolt Unlversal at 210 F. was diluted for the color de termination in the -following proportions: 15 parts of -oil with 85 parts of 21 color (on the Saybolt apparatus) water white kerosene. The color of an untreated sample of cylinder oil (dilute) was 1%. on the Tagliabue-Robinson colorimeter while that of the clay treated oil was 1%. A

It lwill be understood that my process can be applied not only with pipe still distillation units the llightest and heaviest fractions in the frac' tionating zone, and passingv 'the withdrawn stream through a stripping zone in contact with a solid treating agent.

2. The process oftre'ating oil comprising passing the oil stock through a distillation and fractionating zone, withdrawing liquid stream of the reflux oil intermediate of the lightest and heaviest fractions in the fractionating zone introducing the liquid stream obtained inthe fractionating zone into a stripping zone, introducing a slurry of solid treating agent and oil into the stripping zone in contact with the liquid stream, passingsteam through the stripping zone in countercurrent to the liquid stream, returning a mixture of steam and vapors into the frac-1 tionating zone, removing the liquid stream together with the solid treating agent from the stripping zone and. separating the solid treating agent from the liquid stream.

3. The lprocess according to claim 2 in which a liquid stream is introduced into the top portion of the stripping zone andthe slurry of finely divided clay and oil is introduced into the stripping zone at such a height thereof that the finely divided clay stays in contact with the liquid stream-while passing through the stripping zone, the time of contact being controlled by the amount of liquid' held in the bottom portion of the stripping zone.

4. The process of treating oil which comprises passing theV oil stock through a distillation and' fractionatingzone, taking olf vapors from the distillation and fractionating zone, withdrawing a plurality of liquid streams of oil from regions of different temperature in said zone, and passing

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