US 3870625 A
A process for the de-asphalting of residues from the vacuum distillation of petroleum in which the material to be treated is placed in contact with liquid propane.
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Description (OCR text may contain errors)
United States Patent 1 Wielezynski 1 PROCESS AND EQUIPMENT FOR THE DE-ASPIIALTING OF RESIDUES FROM VACUUM DISTILLATION OF PETROLEUM, AND APPLICATION TO THE REMAINING OF LUBRICANT OIL  Inventor: Leck Godfryd Wielezynski, 1 Ave.
George V., Paris, France 22 Filed: on. 17, 1973  Appl. No.: 407,157
 Foreign Application Priority Data Dec. 1, 1972 France 72.37293  US. Cl 208/180, 196/1452, 208/309  Int. Cl. ..C10g 21/14  Field of Search 208/251, 309, 311, 317,
 References Cited UNITED STATES PATENTS Henry et a1. 208/309 Mar. 11, 1975 Fenske et al 208/317 2,850,431 9/1958 Smith 3,178,268 4/1965 Lindstrom 196/1452 3,488,159 1/1970 Moon et al. 196/1452 Primary ExaminerHerbert Levine  ABSTRACT A process for the de-asphalting of residues from the vacuum distillation of petroleum in which the material to be treated is placed in contact with liquid propane. To ensure good contact between the propane and the material, the latter is injected into the liquid propane by pulsations, at the requisite pressure and temperature through a spraying device which causes dispersion of the material in the form of fine droplets.
3 Claims, 1 Drawing Figure PROCESS AND EQUIPMENT FOR THE DE-ASPHALTING OF RESIDUES FROM VACUUM DISTILLATION OF PETROLEUM, AND APPLICATION TO THE REMAINING OF LUBRICANT OIL The invention relates to a process and apparatus for the separation of the asphalts and oils which form the residue from the vacuum distillation of petroleum; this process may also be advantageously applied to the purification and reclaiming oflubricant oils recovered from used mineral oils, called drain oils.
The process according to the invention is based on the known capacity of liquid propane to dissolve, in the form of a selective solvent, the hydrocarbon fraction from which lubricant oils are formed, resulting in the separation and precipitation of asphalts and other nondissolved particles which make up the material subjected to the treatment.
This property of propane has already been applied in different processes which have been put into effect in modern petroleum refineries for the production of basic lubricant oils and asphalts from the residue from vacuum distillation, but the complicated and costly equipment for de-asphalting units of this type is only profitable for the treatment of considerable quantities of residue, and is not economical on the general scale for a plant for the purification and reclaiming of used oils where capacity in practice does not exceed a few metric tons per day.
The object of this invention is to ensure a production of basic lubricant oils from the residue from the vacuum distillation of petroleum, and, in particular, the de-asphalting and purification of lubricant oils from used mineral drain oils, by providing a process capable of being put into operation on a small scale, with the use of simple and inexpensive equipment.
In large reactors, used in plants for the de-asphalting of residues from the vacuum distillation of petroleum, separation of the asphalts and the lubricant oils is effected by simply mixing a specified amount of heavy hydrocarbons into the liquid propane, which dissolves the fraction of the lubricant oils and causes the heavier particles of hydrocarbons and other non-dissolved compounds to precipitate to the bottom of the reactor, while the liquid propane, laden with the dissolved lubricants, being lighter, again rises to the top of the reactor, where apparatus is provided for producing the variations in temperature to facilitate this upward motion, and also provided are means for the continuous evacuation of the mixture, and for the subsequent separation of the oil and its solvent, propane which is, then recycled in the system in the liquid state.
Since the aim of this invention is to limit, as far as possible, the volume of equipment and to treat on an economical basis even small quantities of material containing lubricant oils, asphalts, carbons, and other impurities, such as mineral or metallic dusts, for example, which are found in suspension in the used drain oils, it is necessary to provide means for improving the facilities of contact between the fractions of lubricant oils and their selective solvent, (propane), and also means for the acceleration of accurate and rapid separation of the dissolved lubricant and other materials, nondissolved, and their precipitation.
The object of the invention is embodied in a process for the production of basic mineral oils and of residual asphalts obtained either from the residue from vacuum distillation of petroleum, or from used drain oils, this process being of the type in which the material to be treated is placed in contact with a requisite amount of liquid propane which dissolves the fraction of oil capa ble of being used as lubricant, while the fraction of hydrocarbons and of other non-dissolved materials separates off and hastens, accurately and rapidly, separation of the dissolved oils and the propane being then obtained by vaporization of the propane, this process being characterized by the fact that, to ensure excellent contact between the oil and the propane, its selective solvent, and to obtain accurate separation and rapid precipitation of the asphalts and other non-dissolved materials, the treated material is injected through a pump, suitably adapted to carry out pulsed injections, at an appropriate rate and under the requisite pressure to make the treated material penetrate the extraction area, where the pressure is maintained at an adequate level in relation to the given temperature for the propane to be kept in the liquid state. The pulsed injections of the treated material into the liquid propane are carried out through a spraying device which causes dispersion of the material in the form of fine droplets, facilitating the dissolution of the fraction of lubricant oil in the propane, and the separation and also the precipitation of the non-dissolved fractions of the asphalts, a great number of which have already deposited at the bottom of the extraction area.
I The object of the invention is also embodied in a process for concentrating the dissolved lubricant, allowing it to be separated off from part of the liquid propane, characterized by the fact that the liquid propane forms a reflux at the head of the concentration area, from which a pump recycles it by pulsed injections starting at the head of the first column, against the flow of the treated material continuously introduced into this col umn from the extraction area, which results in the rapid liberation of all the dissolved lubricant and in the precipitation of the asphalts and of the other insoluble particles in the propane.
The application to the processes outlined above of vibrations transmitted to the whole unit, either by an appropriate assembly of the compressor when it is a question of a small-capacity plant, which is specially designed for the scrubbing and reclaiming of used drain oils, for example, or by apparatus fulfilling the same operation in larger units, which are designed for the treatment of residue from vacuum distillation of petroleum, is also an object of this invention, since the effect of these vibrations noticeably improves the output, both in the part of the equipment operating under high pressure where the separation and precipitation of nonsoluble particles in propane takes place, and in the part of the equipment operating under low pressure and/or under vacuum where the separation of the propane and of the purified lubricant take place, by vaporization of the propane which, after having been pressurized and condensed, is recycled in the liquid state in the system.
The equipment used for the application of the processes which have just been briefly described are further objects of the invention.
One form of application of the invention will be described below, as a non-restrictive example, reference being made to the sole FIGURE of the attached drawing which is a diagrammatic illustration of a unit which conforms with the invention.
propane is simultaneously introduced by line 5. As indicated above, the material to be treated is injected through a spraying device into this area, so as to ensure excellent contact with the liquid propane, which dissolves the soluble particles oflubricant, thus facilitating the separation and precipitation of the asphalts and other insoluble particles, which begin to precipitate towards the bottom of this extraction area.
This insoluble residue can be periodically evacuated from the system by pressure to tank 6 by line 7, while the partially scrubbedmixture of oil and propane is transferred by a siphon and line 8 to the area of the concentration system in which final scrubbing of the dissolved lubricant takes place, composed of three columns, 9, l and 11, in which separation of the liquid propane occurs, forming a reflux at the head of these columns composed of liquid propane and a small quantity of the lightest lubricant hydrocarbons of the batch treated. Motorized pump 12 draws this reflux through line 13 at the head column 11, continuously transferring it by means of pulsed injections through the perforated line 14 against the flow of the partially scrubbed mixture, also continuously introduced into the first column of concentration area 9. The vibrations caused by' the pulsed reflux injections, as well as those transmitted to the whole plant, are doubtless the main reason for the phenomenon of the formation of the reflux in this system, operating at an appropriate pressure to keep the propane in the liquid state at a given temperature. The result of this pulsed and continuous passing of reflux is the rapid and accurate precipitation of all the molecules of hydrocarbons and other non-dissolved impurities in the propane, which pour off towards the bottom of columns 9 and 10. The mixture of oil and propane, now greatly purified, is transferred through line 15, which is perforated, to within column this pure mixture then passes through line 16 into the third column, l l, of the concentration system, whence the mixture of oil and propane is introduced through the siphon and line 17 into a system of dry filters 18. At the entrance to this filter system, the control valves no longer monitor the high pressure, and the expansion of the vaporizing propane commences. vaporization of the propane, passing to the gaseous state, causes a sufficient drop in temperature in the filter cylinders to eliminate all traces of any humidity possibly contained in the mixture. The mixture of oil and propane then flows through line 19 into evaporator coil 20, which is heated by heat-exchange with propane gas passing through a similar coil 21, which conveys it from heated tank 22 to compressor 23 by line 5 for compression, condensation and recycling in the extraction area in the liquid state. The clean oil, now separated from its solvent, propane, is withdrawn periodically or continuously into 24L The asphalts and other residual products are periodically sent by pressure from the system at the bottom of areas 4, 9, l0 and 11 through line 7 to heated tank 6, from which the propane gas is drawn up by the compressor through line 25, to be also recycled in the liquid state by line 5 in the extraction area, while the asphalts and other residues are evacuated through 26. The volume of propane in the system can be made up from reserves, 27, by line 28, which brings it to the compressor to be liquefied and introduced into the system.
An advantageous form of arrangement of this type of apparatus, particularly for a unit treating small quantities of material, is for the unit to be assembled on a rigid platform, for example, on four legs and on two levels. The motorized compressor is fixed to the floor of the second level and transmits its vibrations to the entire plant.
1. A method for regeneration of used lubricant oils, comprising spraying used lubricant oil in pulses into the top of a first column, introducing liquid propane into said first column to dissolve a regenerative fraction of the oil therein, removing the thus formed solution of propane and oil fraction from the top of the column along with propane, and undissolved oil in admixture therewith, removing insoluble residue of the oil from the bottom of the column, passing the mixture of oil, propane and oil dissolved in propane successively in a plurality of further columns disposed in series, said mixture being introduced successively into each of said further columns, introducing into one of the further columns, at the top thereof, propane in pulses in counter current flow in said one column with said mixture introduced therein, removing, at the bottom of the further columns, impurities which settle by gravitation in said further columns, removing from the last column a solution of the oil in liquid propane, and separating the oil thus purified from the liquid propane by vapori zation of the latter.
2. A method as claimed in claim 1 comprising imposing mechanical vibration to said columns in order to effect-better contact between the propane and the oil to be regenerated, I
3. A method as claimed in claim 2 comprising compressing the vaporized propane following the separation of the oil therefrom to liquefy the propane and recycling the thus liquefied propane to said first column. i