US2610942A - Extraction process - Google Patents

Description

Sept. 16, 1952 c L. READ 2,610,942

EXTRACTION PROCESS Filed March 51. 1948 QAFFI-QATE %:l 4

'PHENQL x? EXTQAC'FFION Towez Smcomz OIL;

EXTRACT F I .-'i

- l 'SICBJCONE 025501. 25 I (26 2 PROPANE EXTRACT RAFFINATE.

Chester L. Read flavarztor i Cltdbo r 0.2g

Patented Sept. 16 1952 Ghester -L. Read, Westfield, 1N. 3;, assignor to "Standard Oil Development -Company, acomicration of Delaware iip iiieiat'icm -Maren a1, 1948, seriativa rsizsz I This invention relates to improvements in the solvent extraction ofcarbonaceous liquids with Polar solvents and particularly to "improvements in the settling rates of mixtures of the liquid carbonaceous fee'd stocks and polar solvents.

The inventionis more particularly concerned with the use of solvents having a preferential selectivity for the more aromatic type compounds .as I compared with the more .parafifihic type compounds-for the treatment cflp'etroleum oils boiling in the lubricatingoil boilingrange. It is especially-desirable for the treatment-of petroleum hydrocarbons boiling in the lubricatingoil boiling range wherein these oils are treated with a solvent, thergravity of whichsolvent is not greatly diilerent fromthe-xgravity of the. particular lubricating oil being processed. -I n-the extraction of carbonaceous :liquidsthe ieedstocksshould be partially but notcompletely miscible with the solvent and the solvent may-or may not be partially soluble in the undissolved portion of the fee'd stock. This procedure is par- 'aticularlyapplicable "to the "extraction o'f -s'uch-ieed stocks as petroleum oils, Fischer synthesis products, vegetable oils, fats, etc. withselective solvents of the general class of phenols, 'aldehydes, nitrates and esters, specifically, compounds of the type of phenol, cresols, furfural, nitrobeirzene, nitropentane, dibutyl 1 phthalate, sulfurdloxide, 'etc. A particular application 'is the phenolextraction f lubricating oils.

In the "extraction procedure as defined abate, it has been found' that the effectiveness of the process is' proportional to the intensityof the mixing'ofthe two components up to the point where equilibrium is established between the two phases-increased effectiveness being obtained with increased mixing intensity. It has also been found that the rate of phase separation-(after the mixing has been stopped) decreases as the mixing intensity increases. Thus, in any system, whether it be a single-stage or a multi-stage process, the capacity of the system decreases as the efiectiveness of theprocess is increased. -In a countercurrent system, such as a tower, decreasing the sizeof the packing brdecreasingthe size of the holes in the perforated plates results in improvedeificiency-and the stage equivalent-of the ,unit is increased but with a corresponding decrease in its capacity. Any procedure which would increase the capacity of such a system without sacrificing the effectiveness of the extraction process would be of considerable value in commercial operations.

--It, been found that this can be accom- 9 Claims. with-414.42)

a solvent:e djract pliase containing the more aro plished by adding to-suc-h asystem anextremely small quantity of silicone polymer oil, the quantity 'Of' this :oil required ranging from-a few hun- --dr edthsof a-per-cent' -to a ten thousandth oi -a per cent or even less. The silicone polymer oil -may' be added to oil, solvent or mixture of oil and solvent.

The invention may be 'more' readily understood byreference to the drawingsillustratingexper-iments of thesame. u

Figure :1; illustrates the invention wherein a countercur-renttreating tower-is semployedwhile Figure 2 -i llu strates an adaptation of the in-- 'vention' employing a multi-stage unit.

- Referring "specifically to Figure 1, "the solvent, which -forthe purpose of illustration is assumed to "be mono-hydroxy phenol, is introducedinto treating tower l by means of solvent =ieed line =3. The oilto be treated, -which-for-=the purpose oi illustration; is assumed tq :bQ- a (petroleum oil boiling in the-lubricating 'oil boiling range, is introduced-into the bottom section of countereurrent-treating tower l-by meansof feed line 2. Temperature and pressure conditions incountercurrent treating tower l are regulated: to-secure matic constituents, which. phase is withdrawn from the bottom er couritercurrent treating tower I by means of line t. "A raffinate phase compr'ising'the less aromatic maroon-contenstituents and some solvent .is removed irom the t'opof countercurrent treating tower i by nieans of line 4. They rafiinatephase and the solvent extmdtzphase maybe handled by any "suitable means in order to remove 'thesolvent'irom the treated portionsof th'ef'oil. I

in accordance with the present inventiona silicone polymer 611 is 'mtrtauced into aneast one 'Of'the incoming feed s reams. Inti'ficdid- "an'ce with a'preferred adaptation of the present invention, it is desirable to introduce the silicone oil into both "the -incoming-solvent stream the incoming 611i stream. wh'en' ipera ting in acceiuanee with this adaptation of the intestine, the portion of the silicone oil introduced iii'to tlie respective streams is in iproportion ito the solventoil ratio employed.

It is' to be understood that any 'suitable 'distributing and. packing means may be employed-in tower 1. -Furthermore; precipitants' suchka'srwater, alcohbl' and the like may be' "employed; which precipitants may be introduced at any desirable point. Furtlier'more, under certain conditions it may be desirable to emplo ya't'emperature-gradient inthejoperation. Y

Referring specifically to Figure 2, a multi-stage unit is illustrated. The multi-stage unit is composed of stages 10, ll, l2, l3, l4, IS, IS, i1 and [8. Oil is introduced into stage l4 by means of line 20. The solvent, which for the purpose of illustration is assumed to be cresol, is introduced into stage I by means of line 21. The oil and solvent flow ina countercurrent relationship. The raffinate 'phase comprising solvent and the less aromatic constitutents is withdrawn from stage I0 by means of line 22 and handled in any manner desirable for the separation of the solvent and the less aromatic constitutents. The solvent flows from stage In through to stage l8. In accordance with this adaptation of the invention, a solvent having a preferential selectivity for paraflinic type constitutents is introduced into stage I8 by means of line 23. For the purpose of illustration the solvent is assumed to be propane which --is introduced into stage IB and removed with a raffinate phase by means of line 22.

The solvent extract phase comprising cresol and the more aromatic type constituents is removed as a solvent extract from stage [8 by means of line 24.

It is to be understood that any type of distributing and contacting means may be employed in the various stages; that the temperature and pressure may be varied and that any suitable solvent-oil ratio may be likewise utilized.

The silicone polymer oil is introduced either into the solvent line 21 by means of line 25 or into the oil feed line 20 by means of line 26. Here again, it is preferred that the silicone oil be added to both the oil stream and the solvent stream, preferably in the ratio of solvent to oil employed.

The invention generally comprises the utilization of a silicone polymer oil in conjunction with a solvent treating operation wherein solvents having a preferential selectivity for the more aromatic type compounds are utilized. In accordance with the invention, the silicone polymer oil is preferably added to both the incoming oil and the incoming solvent stream as indicated. Under certain circumstances it may be desirable to recover the silicone oil from the respective phases by distillation or any other suitable means. However, in general, the amount of silicone polymer oil employed is of such a low magnitude that recovery or separation of the same from the products of the treating operation'is not necessary or desirable.

The present invention may be further understood by the following examples, illustrating further adaptations of the same:

Example 1.-A petroleum oil boiling in the lubricating oil boiling range secured from a La Paz crude and having a gravity of about 23 A. P. I. was segregated into two portions. Each portion was mixed with an equal volume of phenol and the respective mixtures stirred at a constant rate for five minutes. One mixture was stirred at a temperature of 120 F., while the second mixture was stirred at 140 F. During the time required for separation, the respective temperatures were maintained.

After the stirring was stopped, the mixtures were settled at these temperatures and it was found that the time required for a complete phase separation was 15 minutes for the 120 F. operation and 10 minutes for 140 F. operation. These experiments were repeated except that 0.01% by volume (based on the oil feed) of silicone polymer oil was added. The settling times for these mix- '4 tures were 12 minutes for the 120 F. operation and 6 minutes for the 140 F. operation.

From the above it is apparent that the addition of this quantity or silicone oil reduced the settling time from about to 40%. This simply means that other factors being equal, the size of the equipment for a given feed and solvent rate can be reduced to a'similar extent.

Example 2.--A feed oil similar to that employed in Example 1, except that the gravity was about 26 A. P. I. was mixed with equal volumes of phenol. A similar operation as described in Example 1 was utilized.

The settling times for the oil-phenol mixtures were 7 minutes for the 120 F. operation and 5 minutes for the 140 F. operation. With the addition of 0.01% of silicone polymer oil based on the oil feed, the settling times were reduced to 4 minutes for both the 120 and 140 F. operations.

From the above, it is apparent that the settling time was reduced from 20 to about 40 Example 3.Additional portions of the feed oils used in Example 2 were treated with phenol and handled in amanner described in Examples 1 and 2, except that 0.03% of silicone oil was employed. The addition of 0.03% of the silicone oil to the mixture gave results identical with those obtained 0.01%.

Example 4.-Four mixtures of an East Texas lubricating oil distillate and phenol were prepared by treating one volume of the distillate with three volumes of phenol at 150 F. for 10 minutes under constant stirring conditions. Silicone oil was added to these mixtures of the quantities of 0%, 0.01%, 0.001%, and 0.0001 After this mixing, the phases were allowed to settle and the time determined. The phases were then separated and stripped of solvent. The complete inspections obtained on these products are given in the following table.

Batch phenol extraction of East Texas 200 neutral distillate in the presence of small amounts of silicone fluid Identification Feed A B O D Conditions:

Silicone Fluid-Weight Percent 0 0. 01 0. 001 0. 0001 Temperature-F 150 150 150 150 Mixing Time-Minutes. l0 l0 l0 l0 Mixing Speed-12. P. M- 1, 780 1, 780 l, 780 1, 780 Phenol Treat-V01. Percent 300 300 300 $0 Settling Time-Seconds. 120 105 95 Waxy Raflinatc:

Yield-Vol. Percent... 55. 7 54. 8 56. 7 53. 2 Gravity-*API 26. 3 32. 2 32. 2 32. 2 32. 2 V/i30-SSU 79. 0 78. 9 78. 4 77. 9 42. 98 42. 98 43. 26 43. 15 0. 802 0. 802 0.802 0. 802 Extract:

Yield-V01. Percent 44. 3 45. 2 43.3 46.8 Gravity-API l9. 5 l9. 7 19. 2 2o. 1 V/210-SSU 52. 91 51. 3 62. 05 50. 40

1 Seconds, Saybolt Universal. Viscosity Gravity Constant.

These results show that the addition of silicone oil had essentially no effect on the yield or quality of rafflnate, the slightly higher quality of raflinate obtained in some cases being oflset by slightly lower yield. Lower settling times were obtained where the silicone oil was added, these values decreasing With decreasing quantity of silicone oil up to 0.001%. It is of interest to note that the addition of the silicone oil had the greatest eflect in reducing settling time where this time was relatively high.

The silicone oil'used to increase settling rates '5 is obtained by polymerizing a dihydrocarbon silicone and would have the general structure W) R; I

where R1 and R3 are hydrocarbon radicals such as alkyl, cycloalkyl, aryl, aralkyl or alkaryl preferably having less than carbon atoms per molecule and a: is a positive integer greater than 1. As an example, dimethyl silicone Viscosity at C 50-1000 centistokes Freezing point Below 50 F. Sp. gr., 25 F 0.968-1001 R. 1., 25 F 14030-1427 The silicone polymer oil used was a dimethyl silicone polymer having the following properties:

Viscosity at 25 F 350 centistokes Sp. gr., 25 F 0.972

R. I., 25 F 1.4032

Polymer oils of this type are soluble in the oil feed to the extent of about 0.06 volume per cent and in the solvent feed to the extent of about 0.03 volume per cent. The quantity of'silicone oil used may vary from a maximum of'about 0.03% by volume (based on total feed to the extraction system) down to less than 0.0001%. The silicone oil may be diluted by dissolving in either the oil to be treated or the solvent and added to the feed in the amounts required. The quantity of the silicone oil added can thereby be better regulated.

What is claimed is:

1. In the extraction of a petroleum crude oil with phenol, the improvement which comprises adding about 0.0001% to 0.03% by volume of dimethyl silicone polymer to the mixtureof crude oil and phenol.

2. In the extraction of a petroleum crude oil according to claim 1 in which the dimethyl silicone polymer is added to the phenol.

3. Improved process for the segregation of a petroleum oil into its more aromatic constituents and into its more parafiinic constituents, which comprises contacting feed oil in a treating zone with a liquid solvent, having a preferential selectivity for the more aromatic type constituents under conditions to secure phase separation, introducing into said treating zone about 0.0001% to 0.03% by volume of a silicone polymer oil, re-

moving a solvent extract phase and a rafiinate phase from said treating zone and recovering the oil.

4. Processes defined by claim 3 wherein said silicone oil is introduced into the treating zone by the addition of said silicone oil to one of said feed streams to said treating zone.

5. Processes defined by claim 3 wherein said silicone oil is introducedinto said treating zone by introducing said silicone oil into said solvent and into said oil being introduced into said treating zone.

6. Processes defined by claim 5 wherein the respective quantities of silicone oil added to the solvent stream and to the oil stream is aboutproportional to the relative proportion of solvent utilized with respect to the oil utilized.

7. In a process for solvent extraction of a viscous petroleum lubricating oil fraction by intimately contacting said fraction with a selective solvent for the naphthenic constituents thereof, the improvement which comprises incorporating in said fraction about 0.03% by volume of a polymer of dimethyl silicone prior to said contacting to thereby accelerate settling of the suspension resulting from said intimate contacting.

8. In a process for solvent extraction of a viscous petroleum lubricating oil fraction by intimately contacting said fraction with a selective solvent for the naphthenic constituents thereof, the improvement which comprises carrying out the extraction process in the presence of a small amount, about 0.03% by volume, based on the total feed to the extraction system, of a polymer of dimethyl silicone to thereby accelerate settling of the suspension resulting from said intimate contacting.

9. In a process for the countercurrent contacting of a petroleum oil fraction with a selective solvent for aromatic constituents thereof, the improvement which comprises carrying out the countercurrent contacting process in the presence of a small amount less than about 0.03% by volume of a. silicone polymer oil, and thereafter removing a solvent extract phase and a raflinate phase from said treating zone and recovering the petroleum oil fraction.

I CHESTER L. READ.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,383,521 Sowa Aug. 28, 1945 2,383,768 Buis et al Aug. 28, 1945 2,406,671 Diamond p ,r, v Aug. 27, 1916

Claims (1)

1. 3. IMPROVED PROCESS FOR THE SEGREGATION OF A PETROLEUM OIL INTO ITS MORE AROMATIC CONSTITUENTS AND INTO ITS MORE PARAFFINIC CONSTITUENTS, WHICH COMPRISES CONTACTING FEED OIL IN A TREATING ZONE WITH A LIQUID SOLVENT, HAVING A PREFERENTIAL SELECTIVITY FOR THE MORE AROMATIC TYPE CONSTITUENTS UNDER CONDIJTIONS TO SECURE PHASE SEPARATION, INTRODUCING INTO SAID TREATING ZONE ABOUT 0.0001% TO 0.03% BY VOLUME OF A SILICONE POLYMER OIL, REMOVING A SOLVENT EXTRACT PHASE AND A RAFFINATE PHASE FROM SAID TREATING ZONE AND RECOVERING THE OIL.

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