US2161405A - Contacting apparatus - Google Patents

Description

AJune 6, 1939. J. W.BROWN CONTAOTING APPARATUS Filed Aug. lea,` 1956 n W M Rm A m5. JM d W R w d WM .m m AA p f .J f Y a. B r .f r w, 5 w w. A Q A f w 5 f M ,n d w .i n i., TTV ,A Valve n,

Patented June L6,A 1939 CONTACTING APPARATUS John W. Brown, Baltimore, Md., assignor to Continental Oil Company, Ponca City, Okla., a corporation of Delaware Application August 19, 1936, Serial No. 96,802

5 Claims.

My invention relates to a contacting apparatus and more particularly to an apparatus for contacting liquids of different specic gravities, as for example, contacting hydrocarbon oils for .treatment with selective solvents.

Hydrocarbon oils must be rened'before they can be successfully employed as lubricating oils. VA crude lubricatingY distillate or residuum is made up of a mixture of hydrocarbons. Some of these compounds are highly parailnic, some are of intermediate character, and Some are highly naphthenic or asphaltic. Processes have been developed whereby the oils to be treated are passed into contact with respective selective solvents which are adapted to selectively dissolve the paraiiinic and non-paraffmic components. These processes permit the renner to completely wash the paraiinic oil of its naphthenic constituents andQat the same time, to completely recover the paraiinic oil from the naphthenic residue.

`One object of my invention is to provide an apparatus for c-ontacting hydrocarbon oils with se- 4lective solvents by counter current contacting.

In general, my invention contemplates the pro-` vision of apparatus in which naphthenic and parainic solvents are passed into contact with the oil to be treated in counter current flow, that is, the fresh paraiiinic solvent is brought into contact with oil previously treated by parailinic solvent which is being progressively used. Similarly, the naphthenic solvent is brought into contact with oil which has been previously treated by partially used naphthenic solvent.

More particularly referring now to the drawing, La tower I, which may be made of sheet steel or any other suitable material, is provided with a number of decks 2. Each deck is provided with a plurality of downwardly extending tubes 3. The tubes 3 communicate with the decks 2 and have their lower ends covered with cap members 4, of any suitable design. The cap members are such that their upper lips project beyond the lower ends of tubes 3. The small pools of liquid .which gather in respective caps 4 are adapted to lowerV decks are pipes 6, 1, and 8, controlled by valves 9, IIl, and II, respectively. Pipesr 6, l, and 8 enter a manifold I2 communicating with a line I3. Communicating with a plurality of upper decks are pipes I4, I5, and IB, controlled by valves I?, I8, and I9 respectively. The pipes I4, I5, and itcommunicate with a manifold 20, which communicates with pipe 22. 23 and 24 provide communication with a plurality of intermediate decks of the contactor and the pipe 2|. Pipe 23 is controlled by a valve 25, and pipe 24 is controlled by a valve 26. Also communicating with a plurality of intermediate decks of the contactor are pipes 21, 28, 29, and 30, controlled by valves 3 I, 32. 33, and 34, respectively. The pipes 2l, 28, 29, and 3P) communicate with a manifold 35 which communicates with a pipe 36. The top of the tower I is provided with a pipe 31 controlled by a valve 38. The bottom of the tower is provided with a pipe 39 controlled by a valve 4G.

In operation I may employ as a nap'nthenic solvent any one of a number of solvents known to the art, such as a cresol base, iurfural, phenol., B-B dichlor ethyl ether, crotonaldehyde, nitrobenzene, sulphur dioxide, and the like. For the parainic solvents, I may employ propane, ethane, butane or the like. The parafnic solvent is always very much lighter than the naphthenic solvent and the solution of propane and the hydrocarbon oil is always lighter than the naphthenic solvent, the use of the apparatus being so controlled as to make a solution through which the naphthenic solvent will flow. The naphthenlc vsolvent is not miscible with the parainic solvents.

In operation, the hydrocarbon oil to be treated is introduced through line ZI by pump 4i and is pumped through either lines 23 or 24 or both, depending upon the position of valves 25 and 23, and is discharged through the line 23 or 24 or both, into the tower at an intermediate deck or decks thereof. The paraiiinic solvent is pumped by pump 42 through line I3 and is introduced to one or a number of lower decks of the tower, de-

pending upon the position of valves 9, I6, and II. The naphthenic solvent is introduced through line 22 and is pumped by pump 43 through line 2i! and is introduced to one or a number of upper decks of the tower, depending upon the position of valves I1, I8, and I3. In the drawing, the

feathered arrows indicate the path' of flow of the parainic solvent and the plain arrows indicate the path of flow of the naphthenic solvent.

It will be observed that, in each succeeding deck of the tower going toward the top thereof, the liquid will have increasingly stronger concentrations of paraliinic substances. In one of the lower decks of the tower, the oil has already been contacted with parainic solvent so that a smaller percentage of paraiiinic substances will be presentin the oil moving toward the bottom of the tower. In order to dissolve these smaller A number of pipes f percentages of paraflinic substances from the oil, fresher paraflinic solvent must be employed. This is automatically taken care of by introducing the paraflinic solvent at the lower decks of the tower. Similarly, the liquid in the tower will have increasingly smaller concentrations of naphthenic substances toward the top of the tower. In one of the upper decks of the tower, the concentration of naphthenic substances will be small and, in order to remove them, fresher naphthenic solvent must be employed. This is accomplished by introducing the naphthenic sol"- vent at the top of the tower. It will be observed that, in my construction, the freshest naphthenic solvent contacts the oil having the least naphthenic substances present and the freshest parafnic solvent contacts the oil having the least paraiiinic substances present. The naphthenic solvent owing down the tower will dissolve naphthenic substances so that the lower` decks of the tower will have solutions of naphthenic substances in the naphthenic solvent and will form a naphthenic layer or layers in the lower deck or decks of the tower. Similarly, the solution in the upper decks of the tower will be parainic substances, in solution in the paraflinic solvent.

The naphthenic solvent which is of high speciiic gravity will flow downwardly from compartment to compartment, through the tubes 3 and iiow over the lips of the caps 4. Each compartment of the tower formed by adjacent decks 2 and the side walls of the tower acts as a contact ing and settling unit in a multistage system. In each deck space, the two layers are brought into intimate contact and the layers are then allowed to separate before passing onward to the ynext contacting step. It will be observed that, as the paraiinic and naphthenic layers approach the opposite ends of the tower, they come into contact with more and more concentrated solutions of the opposite selective solvent. Hence, the paranic layer is stripped of its naphthenic content and the naphthenic layer of its paraffmic content, and the apparatus is such that the contact is more complete.

In adjusting the tower during commencement of operations, depending upon the specic gravity of the hydrocarbon oil charge, it may be desirable to vary the concentration of the parafnic solvent such as propane. This can readily be accomplished by opening one of the valves 31|, 32, 33, or S and withdrawing liquid from one of the decks with which the lines controlled by the valves communicate.

The tower may be used for contact with a single selective solvent; for example, if it is desired to treat with propane, only propane would be introduced at the bottom and the hydrocarbon oil to be treated through the manifold 2Q. Similarly, if it is desired to treat only with a naphthenic solvent, the hydrocarbon oil to be treated will be introduced through manifold IZ and the naphthenic solvent will be introduced through manifold 20. Since all hydrocarbon oil consists of naphthenic and paraiiinic substances, the hydrocarbon oil will be thus separated into two layers which are withdrawn through respective drawoifs 31 and 39. 'I'he naphthenic and parafnic solvents are then recovered by appropriate treatment. The parafnic layer, for example, may be treated for dewaxing by any one of a number of suitable processes. The naphthenic layer may be deasphaltized. It will be observed that the Wax is concentrated in the paraiiinic layer and the asphalt compounds are concentrated in the naphthenic layer. By use of my apparatus, only the paranic layer need be subjected to dewaxing and only the naphthenic layer need be subjected to deasphaltizing.

It will be observed that I have accomplished the objects of my invention. I have provided a counter current contacting unit for the treat ment of hydrocarbon oils, which may be advantageously employed for solvent treating processes.

It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of my claims. It is further obvious that various changes may be made in details within the scope of my claims without departing from the spirit of my invention. It is, therefore, to be understood that my invention is not to be limited to the specific details shown and described.

Having thus described my invention, what I claim is:

1. In a contacting apparatus, a shell, a plurality of decks extending across said shell at vertically spaced positions, said decks forming a plurality of vertically spaced compartments, each deck provided with a plurality of downwardly eX- o tending tubes, the upper ends of said tubes being substantially iiush with the respective decks from which the tubes depend, cap members spacedly positioned over the lower ends of said tubes, adapted to form receptacles in which liquid may collect to form liquid seals for said tubes, and conduits extending upwardly from each deck alternately adjacent opposite walls providing additional communication between adjacent compartments for directing the flow of lighter fluid across the compartment space.

2. A contacting apparatus as in claim 1 provided with means for introducing liquid to a deck at the lower portion of said shell.

3. A contacting apparatus as in claim l, provided with means for introducing liquid to a deck near the upper portion of said shell.

4. A contacting apparatus as in claim l in which said shell is provided with means for introducing liquid near the bottom thereof, means for introducing liquid near the top thereof, means for introducing liquid near the center thereof, and drawoifs at the top and bottom of said shell.

5. In a contacting apparatus, a shell, a plurality of decks extending across said shell at vertically spaced positions, said decks forming a plurality of vertically spaced compartments, each deck provided with a plurality of downwardly extending tubes, the upper ends of said tubes being substantially flush with the respective decks from which the tubes depend, cap members spacedly positioned over the lower ends of said tubes, said cap members forming receptacles in which liquid may collect to form liquid seals for said tubes, conduits extending upwardly from each deck alternately staggered, providing additional communication between adjacent compartments for directing the ow of lighter fluid transversely of the compartment spaces, saidconduits terminating short of the plane of the ends of said downwardly extending tubes.

JOHN W. BROWN.

Images