US2091917A - Apparatus for treating mineral oils - Google Patents

Description

Aug. 31, 1 937. 7 M.- R. FENSKE ET m. 2,091,917

APPARATUS FOR TREATING MINERAL OILS Eiigd Sept. 6. 1935 2 S he ets=-Sheet 1 Fig.1 B

Y JYTORS' BY Fig. 1A

Aug. 31, 1937. M FENSKE ET AL Q 2,09 191 7 APPARATUS FOR TREATING MINERAL OILS Filed Sept. 6, 19:55 2 Sheets- Sheet 2 Patented Aug. 31, 1937 APPARATUS FOR TREATING MHVERAL OILS and Wilbert B. McCluer, State assignors to Pennsylvania Petroleum Research Corporation,

Mcrrell R. Fenske College, Pa.,

Pennsylvania a corporation of Application September 6, 1933, Serial No. 688,416 2 Claims. '(Cl. 196-46) ing molecules of a certain size in preference to This invention pertains generally to the processing of mineral oils and pertains particularly to the extraction and/or fractionation of such oils.

5 This invention will be described in connection with the solvent extraction or fractionation of lubricating oils. However, it is to be understood that it is adapted to the treatment of any other fractions or combination of fractions including over-all and reduced crudes- Among the prior processes for the solvent extraction of mineral oils are those which are generally known as single batch, multiple batch,

batch countercurrent, and continuous counter-- current.

A single batch process merely comprises mixing and thoroughly, agitating the oil and solvent and allowing the mixture to settle. Since the two liquids are only partially miscible and are of different densities, separation into two layers occurs. The two layers are separated by any suitable means such as by decantation. One of the layers consists principally of oil with a small amount of dissolved solvent. This oil is generally regarded as being the'improved oil and is called the raifinate. The other layer consists of the bulk of the solvent with a part of the oil dissolved therein. This oil is generally regarded as being less valuable and is called the extract.

The solvent and oil of each layer are then separated by any suitable means such as distillation and the solvent is thus recovered.

By a careful selection of the solvent employed it is possible to improve the lubricating qualities of the raflinate over that of the original oil, for

instance by increasing its viscosity index, its flash point' and its fire point, and/or by decreasing its Conradson carbon residue. In this case the extract will generally have a viscosity index, a flash point and a fire point below that of the original oil, will be very dark or black in color, and will usually contain a larger part of those materials which are responsible for carbon formation.

Also by a careful selection of the solvent it is possible to fractionate a mineral oil.

Fractionation by the use of solvents as involved in this invention differs from extraction by the use of solvents in that whereas the latter employs solvents which are selective as to type of molecule, the solvents generally dissolving asphaltic and naphthenic compounds in preference to paraffinic compounds, the former employs solvents which are selective as to size of molecule, the solvents dissolving compounds havcompounds having molecules of a different size, regardless of whether such compounds are of the paraflinic, napthenic, or asphalitic variety. Nitrobenzene, acetone, dichlordiethylether, and phenol are solvents which are selective as to type of molecule and certain monohydric aliphatic alcohols are solvents which are selective as to size of molecule as set forth in our copending application Serial No. 731,778 filed June 21, 1934.

The procedure in both cases may be the same, therefore the process and apparatus employed may be the same.

The multiple batch method employs a plurality of batches and is similar to the single batch method asfar as each batch is concerned. The only difference is that the oil is treated several times, each time with fresh solvent.

The batch countercurrent method is somewhat similar to the multiple batch method in that the oil is treated several times. However, the solvent is used once in each batch and moves countercurrently to the oil between the batches.

While the batch countercurrent method is much more efficient than the single batch or multiple batch methods, it has many limiting features among which are the limit on the practical number of batches that can be employed (to obtain ideal conditions an infinite number is necessary), the time required for settling, which ties up large quantities of oil and solvent in process, and the large outlay which is required for suitable equipment.

Theoretically, continuous countercurrent systems should be more eflicient than any of the foregoing. In practice, however, great difiiculties have heretofore been experienced in obtaining an efficient and uniform contact between oil and solvent due, among other things, to the persistent tendency of the liquids to channel through each other. I

In contrast to the foregoing this invention rehates to the solvent extraction and/or fractionation of mineral oils by the continuous countercurrent fiow of oil and solvent wherein the solvent and' oil are brought into intimate contact under the most ideal conditions for the practical realization of equilibrium conditions in a countercurrent extraction system. The countercurrent flow is continuous in every respect and is brought about through the difference in densities of the solvent and oil.

Further features of the invention reside in the construction, arrangement and combination of parts, and in the steps, and combinations and sequences of steps, all of which together with further features will become more apparent to persons skilled in the art as the specification proceeds and upon reference to the drawings in which:

Figures 1A and 13 comprise a sectionalelevation of a different form of the invention.

Figure 2 is a section on line 2-2 of Figure 1A.

Figure 3 is a section on line 33 of Figure 1A.

Figure 4 is a section on line 4-4 of Figure 13.

Referring now more particularly to the drawings column 45 having certain desired characteristics is illustrated as having a shell 46 with plates 41 and 48 at its ends. Plates 41 and 48 are shown integral with flanges 48 and 50 respectively.

Plate 41 has a plurality of apertures 5| in which are inserted tubes 52 which extend downwardly into shell 46.

Plate 48 is shown as having a plurality of apertures 53 of a diameter somewhat larger than that of the apertures 5|. Each aperture 53 is shown provided with a tube 54 which extends upwardly into shell 46.

The upper feeding chamber 56 is shown divided into two parts 51 and 58. Part 51 has a lower flange 59 which cooperates with flange 49 and an upper flange 60 which cooperates with a flange 6| on part 58. Flange 6| is integral with a perfo- 30 rated plate 62 which extends across the lower end of part 58. Part 58 is provided with a tubular opening 63 for the ingress of the heavier liquid. Chamber 64 to show the head on the heavier liquid.

The lower feeding and segregating chamber 66 is also divided into two parts 61 and 68. Part 61 is provided with an upper flange 68 whichcooperates with flange 58 and a lower flange 18 which cooperates with flange 1| on the part 68. Flange 1| is contiguous with a perforated plate 12 which extends across the upper end of part 68.

Plate 12 supports a plurality of tubes 13. Tubes 13 are of a lesser diameter than tubes 54. Each tube 13 is more or less axially aligned with a tube 54 and extends upwardly therethrough, thereby providing an annular space 14 between the outer wall of each tube 13 and the inner wall of its respective tube 54. Each tube 13 has a plurality of openings 15 adjacent its lower end. The perforations 15 are preferably below the level of aperture 16 in the side wall of part 61. Aperture 16 is provided with a tubular extension 11 for the ingress of the lighter liquid.

Part 68 at its lower end communicates with a tubular member 18 for the egress of heavier liquid. Tubular member 18 may be provided with a valve 19 to control the flow of liquid. A sight glass 80 is provided to show the level of the heavier liquid in chamber 66.

60 Plates 62 and 12 are adapted to support therebetween a plurality of attenuated members 82 such as jack-chain or the like. Each member 82 is attached to plates 62 and 12 as by eye bolts 83 and 84 respectively. Each tube 13 is preferably more or less axially aligned with a tube 52 and each member 82 passes through a pair of such aligned tubes.

The upper segregating chamber 86 comprises substantially that portion of the inner volume of shell 46 which surrounds the tubes 52. Chamber 86 is provided with an overflow through tubes 81.

Shell 46 may be provided with a jacket 88 or any other suitable means for heating or cooling purposes.

In operation,

7 the heavier liquid is fed into 56 may be provided with a sight gauge chamber 56 through the tube 63. This liquid flows from part 58 into part 51 through the perforations of plate 62. Since tubes 52 are preferably of substantially the same size, which is likewise true of those portions of members 82 which pass through tubes 52, the heavier liquid will be fed more or less uniformly down through each tube 52 and over its respective attenuated member 82. The clearance between each member 82 and its respective tube 52 is preferably such that the heavier liquid willat least begin to follow the member 82 down through the shell 46. This liquid follows the member 82 and eventually flows down into the respective tube 12, then into part 61 of chamber 66 through apertures 15, and then down through perforated plate 62 into part 68.

The lighter liquid is fed in through aperture 16 and flows upwardly about tubes 13 and into shell 46 through the annular spaces 14. By this arrangement the. lighter liquid is directed up about the members 82. The lighter liquid continues to flow upwardly and become segregated from the heavier liquid in chamber 86 from which it is removed by overflow through tubes 81.

Members 82 may be of any desired number and obviously may be closely spaced. A limited number only is shown for the purpose of clarity.

Any part of the heavier liquid which separates from the members 82 will flow downwardly through the lighter liquid and will collect about the tubes 54 until it is sufliciently high to overflow the same. The heavier liquid will then drain into part 61 of segregating chamber 66 and will settle into the heavier liquid issuing from the apertures 15. Tubes 54 may be dispensed with if desired, whereupon apertures 53 will in a measure at least serve their purpose and will permit the immediate drainage'of any heavier liquid leaving members 82.

A constant head is preferably provided for the inflowing heavier liquid and for this reason sight gauge 64 heavier liquid is preferably maintained at a suitable level in chamber 66 for which purpose sight gauge 80 has been provided. Valve 19 may be employed to maintain this level.

It will be noted that in this form of the invention, the heavier liquid is maintained in a plurality of separate streams ofsubstantlally equal size as it passes through the column. In a sense, the lighter liquid may also be regarded as being maintained in a plurality of separate streams of substantially equal size since it is fed up through the annular openings 14 in equal amounts. However, it will be obvious that this is not strictly true with respect to the lighter liquid.

The heavier liquid is spread out into a plurality of thin films which are formed and reformed as has been provided. Likewise, the

the heavier liquid passed down through the column and efficient contact with the lighter liquid is thus obtained.

The above description is based upon the assumption that the heavier liquid will tend to cling to the members 82 in preference to the lighter liquid. If this is not true, then it is merely necessary to construct the column up-side down so that the lighter liquid may pass through the tubes 52 and may thus be caused to flow up through the column on the members 82. In this event the lighter liquid would be fed through tube 63 and withdrawn through tube 18 and the heavier liquid would be fed through tube 11 and withdrawn through tubes 81.

It is, of course, to be understood that any other suitable construction may be provided.

For instance other suitable means may be provided for metering the feed liquids or for separating the final phases. Thus tubes 54 and I! might be eliminated. The separation in chamber 68 would then be by simple layer formation, and the lighter feed liquid would be distributed laterally of the tower by virtue of its layer. This arrangement might be preferred, for instance, when the continuous phase preferentially wets the attenuated members 82.

Furthermore while the metering onto the individual attenuated members 82 of the feed liquid which preferentially wets these members is preferred, it is not an indispensable feature and other constructions may be employed, for instance, in

case there should be no clearly defined preferential wetting.

The column may be operated at any suitable temperature, for instance, by flowing a suitable heating or cooling fluid through the chamber 88 provided by. the Jacket 88.

The column may be operated at any desired pressure. This pressure may be atmospheric, particularly if the solvents are liquid at atmospheric pressure, or elevated, particularly if this is necessary to maintain one or more of the solvents in the liquid phase (partially or wholly,-

as desired) while in the column, or reduced,

should this be desirable for any reason. for instance to bring a part of the solvent or solvents into the vapor phase.

The solvents employed may comprise a single or a plurality of compounds. When a plurality of compounds are employed these may be miscible or partially miscible. A plurality of nonmiscible solvents might also be employed.

When a plurality of solvent compounds are employed these may be fed into the column in any desired manner and at any desired point or 40 points, for instance together, or one or more might be fed in with the oil or at any other point.

In the apparatus described, when the result is the formation of two non-miscible solutions of different density, one of these solutions will be segregated and taken off at the top of the column and the other will be segregated and taken oil at the bottom of the column.

Should the result be the formation of more than two non-miscible solutions such as three.

the third solution will either rise with the lightest solution or will settle with the heaviest solution depending among other things upon the relative densities of the solutions, and the rates and points of feed of the various liquids into the column.

The third solution may be removed from the column along with the lightest solution or along with the heaviest solution as the case may be and the two solutions may be separated by any suitable means such as by decantation.

However, the segregating chambers at the top and bottom of the column may be so constructed as to continuously segregate the two solutions.

While the invention has been particularly described in connection with the treatment of mineral oils, it may also applied to the treatment of materials in general, whether or not the more valuable, the less valuable, or an equally valuable material is separated from thebase material.

While in the foregoing constructions the oil and solvent or solvents are illustrated as being fed into the column at the ends thereof, this is by no means an essential feature. One or more of any of these liquids might be fed into the column at an intermediate point or points if desired forany reason or certain of these liquids might befed in at the ends while one or more of the liquids are fed into the columns at an intermediate point or points. The density of the respective liquids and the densities of the solutions formedwill be taken into consideration when more than two feeding points for the column are employed.

The term solvent in its broader phases includes any compound or compounds whether in the vapor, liquid and/or solid phase and regardless of its'influence upon the base material, for instance a solvent might be added to modify a solution of a part or of all of the base material with another solvent such as to cause precipitation of a part or all of the base material, for instance oil may be precipitated from a solution of pyridine and oil by the addition of methylcellosolve as described and claimed in copending application Serial Number 704,052 filed December 26, 1933.

For convenience in description, the term vertically, as used in the specification and in the claims in describing the position of the attenuated members 82 is intended to include not only a position wherein the attenuated members are perpendicular to the horizon but also a position wherein they are suiflc'iently so to function for the purpose set forth herein.

Having described the invention, it is obviousthat changes, omissions, additions, substitutions and modifications other than those specifically mentioned may be made without departing from the broad concept of the invention and therefore the claims herein are intended to be limited only as required by the prior art.

We claim:

1. Apparatus comprising, a column, a plurality of attenuated packing members vertically arranged in said column, said packing members being separated from each other, means for causing a mineral oil and a solvent to flow countercurrently through said column. means for substantially uniformly feeding at least one of said liquids onto said attenuated members, said attenuated members comprising continuous strips of jack chain.

2. Apparatus for contacting liquid phases such as in the solvent treatment of mineral oils, comprising a phase contacting column, a phase contacting zone in said column. and a plurality of closely spaced attenuated packing members vertically arranged in said phase contacting zone and extending continuously therethrough, said attenuated packing members comprising lengths of chain.

MERREIL R. FENSKE. WILBERT B. McCLUER.

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