US1966624A - Process for refining hydrocarbon oils - Google Patents

Description

July 17, 1934. R. T. HASLAM PROCESS FOR REFINING HYDROCARBON OILS Filed Aug. 24. 1929 .M; .QYZM. (1420144444 Patented July 17, 1934 UNITED. STATES PROCESS FOR REFIIIWLING HYDROCARBON S Robert T. Haslam, Westfield, N. J., asslgnor to Standard-I. G. Company Application August 24, 1929, Serial No. 388,276

1 Claim.

The present invention relates to the art of producing valuable hydrocarbon product from crude oils, shale or coal oils and the like by means of an improved combination process involving the 5 use of at least two stages in the first of which high pressure hydrogen is used under high temperature conditions and the second involving the use of a selective solvent for certain hydrocarbon products. My invention will be fully understood from the following description.

In two prior applications Serial No. 389,677 filed August 1929, and Serial No. 379,086 filed July 18, 1929, in the name of Edgar M. Clark, processes for the improvement of burning oil and lubricating oils by action of high pressure hydrogen under temperature in excess of about 750 Rand preferably in presence of catalysts have been disclosed. In the first of the above applications it is shown that a burning oil out rich in olefinic and aromatic hydrocarbons can be treated with high pressure hydrogen so as to yield a large quantity of a much improved buming oil. In the second application such treatment is found suitable for lubricating oils and 25, greatlyimproves the viscosity-temperature characteristics of the oil.

I have found that purification by the above method is expensive, particularly if used to improve very bad natural oils and to render them equal or better than the best products, burning oils and lubricants, which can be obtained from Pennsylvania or equivalent crudes. But at the same time I have found that it is thelast degrees of improvement which brings up the cost and gives rise to a considerable lossof valuable products as gas and/or lighter liquid products. My present process combines the high pressure hydrogen treatment as a'preliminary stage with a secondary stage of solvent extraction by which 40 extremely valuable oils of the highest quality can be produced with a reasonable cost.

In the practice of my invention the high pressure hydrogen treatment is carried out in any suitable type of apparatus well known in the art. Temperature is in general in excess ofabout 750 F. and is preferably below about 900 F. Pressure is in excess of 20 or atmospheres but is preferably from 100 to 200 atmospheres or higher and the time of contact is regulated so as 50 to limit the decomposition to less than about 20% of light oil boiling below about 400 F. but

preferably below 15 or 10% or even 5% by volume. Catalysts may be used such as the oxides of molydenum and chromium either alone or in combination with other oxides such as zinc oxide,

magnesia and the like.

' The oil fractions boiling above 400 F. recovered from the high pressure hydrogen treatment are cooled, preferably washed with alkali and subjected to a solvent extraction process using a suitable solvent capable of preferentially removing aromatic and/or olefinic hydrocarbons. The mode of carrying out this process depends on the particular solvent used, for example if sulphur dioxide is used the temperature and pressure are maintained such that the sulphur dioxide is in a liquid condition. With aniline or furfural usually atmospheric pressure is maintained and the temperature generally is somewhat above atmospheric. Phenol with 5 to 15% of water may be used or phenol with organic. materials such as glycerine, glycol, ethylene glycol and the like. With phenol and water the temperature is below 200 F. but with the other mixtures, temperature may be above 200 F. and these are particularly advantageous when oils heavier than kerosene are treated.

Amyl, butyl or isopropyl alcohols or acetone may also be used, particularly in mixtures with each other or with naphtha and the like.

The treatment may be batch or continuous and counter-current treatment is advantageous in reducing the volume of solvent necessary. In

all of these processes the purified oil, usually containing a relatively small amount of solvent, is recovered from an immiscible lower layer comprising the bulk of the solvent and the extracted material. The solvent may be recovered in any suitable manner such as by release of pressure and liquefaction as in the case of sulphur dioxide, vaporization i'n of lower boiling solvent or by acid or alkaline wash, depending on the particular properties of the solvent, as will be understood.

The practice of my invention will be fully understood from the following description andthe drawing. The drawing is'a semi-diagrammatic view in sectional elevation of a suitable type of apparatus for accomplishing the process.

In the drawing, reference character 1 designates a high pressure pump which draws oil from any suitable storage tank (not shown) through line 2, forces it' through line 3', heat exchanger 4 and line 5 into a heating coil 6 mounted in a suitable furnace setting 7 which is preferably fired by gas, although other heating means may be used. In coil 6 the oil is heated to a temperature in excess of about 750 F. andthe hot oil then passes through line 8 and discharges through a suitable series of openings into a. high pressure reactor 9. Reactor 9 may be covered with a layer of suitable insulating material 10 and preferably contains a catalytic material 11, the nature of which will be described below. Reactor 9 is main-. tained under pressure of hydrogen in excess 6f 20 atmospheres, preferably 50, 100, 200 atmospheres or more, and at temperatures in excess of 750 F. but below about 900 F. Reactor 9 is constructed of materials which will withstand the high temperatures and pressures to which it is subjected as well as the corrosive effect of hydrogen and the reactants.

Hydrogen or a gas rich in free hydrogen is drawn from any suitable holder (not shown) through line 12 into compressor 13 wherein it is compressed to the pressure maintained in the reactor and is then forced through line 14 which meets line 5 carrying fresh feed oil so that a mixture of oil and hydrogen may be formed before passage through the heating coil 6. Hydrogen may be admitted directly to the reactor through line 15 if desirable. Hydrogen may also be admixed with fresh oil before passage through heat exchanger 4 by means of line 16 which meets line 3.

Hot products flow out of reactor 9 through line 17, pass through heat exchanger 4 and flow through line 18 into drum 19 wherein gases and vapors are separated from liquid. Liquid is drawn off from drum 19 through line 20 flows past pressure release valve 20a, and discharges into a fractionating tower 22, which may be equipped with bubble cap plates 23, cooling coil 24 and heating coil 25. Pressure is substantially reduced at pressure release valve 20a, preferably to about atmospheric.

The gases remaining uncondensed in drum 19 contain a substantial quantity of free hydrogen which may be advantageously recirculated to the reactor. These gases leave drum 19 through line 25, pass througha purification system 26, wherein they are freed-of hydrogen sulfide, ammonia, uncondensable light hydrocarbons and other impurities, and the purified gas is then drawn into a booster compressor 27 which recompresses it up to reactor pressure, and forces it through line 28 into fresh hydrogen line 14.

Low boiling fractions, such as those boiling below 400 or 450 F. which may have been formed in the hydrogenation treatment pass out of fractionating tower 22 through line 29, fiow through a cooler 30, and thence into drum 31, fitted with gas release line 32 and liquid draw-off line 33.

Intermediate boiling fractions may leave tower 22 through line-34 and collect in drum 35 fitted with pressure equalizing line 36 and liquid draw off lines 3'7 and 38.

The heaviest fractions can be withdrawn from tower 22 through line 39 or through line 40 from which.latter they flow into drum 41 fitted with gas release line 42 and liquid draw off line 43.

The fractions collected in either drum 35 or drum 41 may be withdrawn by pumps 44 and 45 respectively and forced through lines 46 and 47 and line 48 into the base of tower 49 which is substantially filled with jackstones, jackstone chain, or other similar packing. A solvent such as liquid sulfur dioxide, phenol, aniline and the like stored in a suitable drum 50 flow through line 51 into the top of tower 49. The oil being less dense than the solvent will rise through tower 49 as the solvent flows downwardly. At the top, raflinate flows out through line 52 and may be collected in drum 53. At the bottom, the solvent and extract flow out through line 54 and collect in drum 55.

By use of this combination process very much improved burning oils can be produced from fractions boiling above the gasoline range but totally unfitted for the purpose because of presence of hydrocarbons, which cause serious smoking. At the same time the oil will be also greatly improved as to color, color holding properties and sulphur content. Lubricating oils from Coastal and Colombia crudes, which are characterized by a low gravity and flash in relation to viscosity and by a small ratio of viscosity at 210 F. and 100 F. respectively, can be rendered equal or better than natural oils derived from Pennsylvania 0r equivalent crudes. The gravity is raised, the flash may be raised so as to be higher than that of a Coastal oil of the same viscosity at 100 F. and the ratio of viscosity at 210 F. to that at 100 F. is greatly increased approximating or even bettering that of Pennsylvania oils of equivalent viscosity at, say 100 F. I do not wish to limit my invention to producing oil equal or better than those of Pennsylvania crude, however, for in many cases it is not desirable to go so far and my process is of considerable advantage in producing burning or lubricating oils below this high standard. The extracted materials both from burning oils and lubricating oils find many uses, the lighter oils being excellent solvents for waxes, gums and the like and the heavier being valuable additive agents to flotation oils and the like.

As an example of the operation of my process the following runs may be considered:

A lubricating oil distillate derived from Colombian crude oil is subjected to high pressure destructive hydrogenation under the optimum conditions for the production of the maximum yield of high quality lubricating oil. A pressure of 3000 pounds per square inch and an average reactor temperature of 733 F. were used. A second portion of the same stock was subjected to a limited destructive hydrogenation under substantially the same conditions except that the reactor temperature was reduced to 720 F. The product of this latter run is then extracted in a countercurrent extraction vessel with 2 volumes of 100% phenol to 1 volume of oil and the extraction is carried out at a temperature of 125 F. The results of these three treatments are shown in the table below in which the characteristics of the feed stock, the first hydrogenated product, the second hydrogenated product and the latter after extraction with phenol are given. The yield of oil in each operation is also given based on the volume of original oil fed to the hydrogenation units:

Combination of hydrogenation and Feed phenol 85 Hydrolube g' Phenol Dist. Light Extrac- #l6 hydrotion of genahydrotion genated product Yield of lube oil 100 65.0 83.0 72. 3

Inspection Gravity A. P. I 21. 5 27. 9 25.7 27. 9 Vis. 100 F. secs. Bay 731 432 650 430 Vis. 210 F. secs. Say 62. 1 58 58. 6 56 Viscosity Index 34 74 53 74 Flash "F 410 430 415 430 Condition; of treatment Average oven temp. "F 733 720 From the above description it will be noted that the yield of the same quality product produced by my combination of hydrogenation and extraction steps is 7.3% larger than when the same quality oil is produced by destructive hydrogenation alone.

The solvents used in the second stage of my process are termed "unreactive selective solvents ess which may be given for illustrative purposes,

but only by the following claim in which I wish to claim all novelty inherent in the process.

I claim:

An improved process for producing valuable refined products from unrefined petroleum fractions of the type of burning andlubricating oils, which comprises partially refining the oil in absence of added, solid, carbonaceous materials by destructive hydrogenation in which the time or contact is adjusted to convert an appreciable,

amount but not more than 20% of the oil into hydrocarbons boiling below 400 F., and then further refining the oil by extraction with a suitable non-reactive selective solvent capable of removing aromatic and unsaturated hydrocarbons.

ROBERT T. HASLAM.

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