US2793751A - Method of and apparatus for removing entrained moisture from oil - Google Patents

Description

T. J. BROIDRICK Filed July 24, 1955 Fl. i

METHOD OF AND APPARATUS FOR REMOVING ENTRAINED MOISTURE FROM OIL May 28, 1957 k w M MW 2 4 w M r a $55 6 "6% fl i n 1:1: if 5 Hum @J 3 m1: do a r 2 4 3 6 A 9 6 MM a B v owwm m o 2 T n 2 M m fig i2 7 G L wvoaw v UJ 2 k I g \H I Q j 5 T L F w w Patented May 2a, 1957 METHOD OF AND APPTUS FOR REMOVING ENTED MOISTURE FROM 01L Thomas J. Broidrick, deceased, late of East Orange, N. J.,

Application July 24, 1953, Serial No. 370,187 4 Claims. (Cl. 210-83) This invention relates to a novel method and apparatus for removing entrained or occluded moisture from substantially water-immiscible liquid compositions.

While the invention may be advantageously employed for the removal of entrained or occluded moisture from various Water-immiscible liquids, such as vegetable oils and the like, it is particularly useful in removing moisture which causes haze to appear in fuel oils, lubricating oils, diesel oils and the like, and is hereinafter described with reference to the treatment of such liquids. But, as will be obvious from the description that follows, the method and apparatus of this invention are broadly applicable to the removal of entrained moisture from water-immiscible compositions which are liquid at the operating temperature and are not injured by intimate contact with the air or other gas used in the method as the moisture absorbing and removing agent.

Fuel oils, lubricating oils, diesel oils and the like, during storage and transportation, usually develop haze, that is, water clouds due to entrainment of moisture particles. Also, as a consequence of certain oil refinery operations, the amount of haze in the oils is frequently increased.

Oil refineries have, for many years, experienced considerable difiiculty in removing haze from their oils for the purpose of obtaining clear and bright oils. The methods heretofore employed by such refineries for the removal of haze have been unsatisfactory because of high initial, maintenance and operating costs.

The present invention provides a novel, eflicient and relatively inexpensive method and apparatus for dehazing such oils and equivalent water-immiscible liquids.

Accordingly, the primary object of this invention is to provide an improved method and apparatus for removing entrained or occluded mosture from substantially Water-immiscible liquid compositions, such as various hydrocarbon oils.

Another object of the invention is to provide an improved method for dehazing oils, whereby to render the same brighter and clearer.

A further object of the invention is to reduce the moisture content of substantially water-immiscible liquid compositions, such as oils having entrained moisture, in a simple, effective and economical manner.

To the end that the foregoing objects may be readily attained, a preferred and recommended method of practicing the invention comprises simultaneously introducing a moisture-containing hydrocarbon oil and air into a treating zone. The oil is subjected to vigorous mechanical agitation in the treating zone, thereby elfecting intimate contact between the air and the oil, the ingredients; and the mixture is successively compressed and permitted to expand to effect separation of moisture particles from other components of the composition and absorption of the moisture particles by the air in the mixture. The air carrying absorbed moisture particles produces foam bubbleswhich rise to thesurface of the oil in the treating zone. The foam and treated oil are transmitted into a settling tank, where the foam 7 is permitted to break, allowing to obtain a mixture of i the air-absorbed moisture to escape, and the treated oil, now in clear, bright condition, is withdrawn.

The oil admitted into the treating zone is at a temperature substantially below its flash point and preferably Within the range of to F., depending on the type and characteristics of the oil. The air admitted into the treating zone may be at atmospheric pressure and temperature. While air is preferred for reasons of economy, any other suitable gas that is non-reactive with oil and that is capable of absorbing moisture may be used in lieu of air. Therefore, the expression air, as used in this description and in the claims, has reference to air, gases that may be used in place of air, or combinations thereof.

The compression and expansion of the mixture, referred to above, is caused in part by the forcing of the mixture between the staves of the rotor and stator and in part by the turbulence, or eddying wake, due to the mixture flowing around the staves, thereby creating varying pressures within the mixture.

The enumerated objects, as well as other objects, together with the advantages attainable by the practice of this invention, will be readily understood by persons skilled in the art, from the detailed description that follows, taken in conjunction with the accompanying drawing, that respectively describe and illustrate a preferred arrangement of apparatus for carrying out the invention.

In the drawing:

Fig. 1 is a generally schematic representation of the apparatus, certain parts being shown in central, vertical cross-section.

Fig. 2 is an enlarged view of a portion of Fig. l, certain additional parts being shown in vertical cross-section; and

Fig. 3 is a view taken along line 3-3 of Fig. 2, parts being omitted for better illustration of other parts.

Referring now to the drawing, wherein like reference numerals denote corresponding parts in the various views, and more particularly to Fig. 1, a supply conduit 5 transmits oil to be treated from a source (not shown) to a settling tank 6. Tank 6 is utilized in instances where the oil contains free water. The free water settles from the oil in this tank and is withdrawn by way of a drain conduit 7, which establishes communication between the bottom of the tank and a water discharge conduit 8. Withdrawal of water from tank 6 is controlled by a valve 9 in conduit 7. Oil and residual entrained moisture collect in the upper portion of the settling tank and are Withdrawn by way of an oil feed conduit 10.

If the oil to be treated does not contain a substantial quantity of free water, it may be transmitted from conduit 5 to conduit 10 by Way of a conduit 11 that bypasses tank 6. Three- way valves 12 and 13, at the junctures of conduit 11 with conduits 5 and 10, respectively, are ported so as to control the flow of oil either through the tank or through the bypass conduit, as desired. In either case, the oil is next transmitted into a treating zone 14.

The treating zone comprises a tank 15 having an open top, across which there is provided a pair of angle supports 16. A plate 17 having a central opening 18 (Fig. 2) is secured to the angle supports. Mounted on plate 17 is a driving unit 20 that includes a base plate 21, having a central opening 22 aligned with opening 18 in plate 17, a plurality of spaced upstanding support members 23 and an explosion-proof electric motor 24, carried by members ing shaft 25 that extends into tank 15.

tioned in tank 15, whereby to impart vigorous agitation 23. The motor includes a rotary drivto and effect compression of materials admitted into the tank. This means, which will now be described, comprises a rotor 26 having a shaft 27 secured to the lower end of shaft 25. and rotatable therewith. The

through the openings between the staves of the rotor and the stator and, in the course of such movement, is compressed and then permitted to expand. As the mixture is forced through the openings between the staves of fowl? also includes P of P Q pfl p fi. the rotor and those of the stator, oil-moisture or moisf 29 that are ecured PP ends; of Shaft ture-oil cells contained in the mixture are broken down, SPlder has a nm30 and PTOVlded P y effecting separation 'of moisture particles from the oil. f Upenlngs SPldeT 29 Preferably ldefltlcfil with As the mixture expands, onv passing outwardly beyond spider 28 and 18 provided wlth a rim 32v and openlngs the stator staves, the moisture particles are absorbed by 33. Disposed between rims 30 and 32 isv a plurality of the air, in the form, of foam which rises in tank 15. This cylindrical, spaced-apart staves 34, best shown in Figs. foam and treated oil are transmitted by spillway 42 into 2 and 3. sump tank 43, where the foam breaks and escapes to Coaxial with and spaced from rotor 26 IS a stat onary the atmosphere and the treated oil, now in bright and stator 35, which includes a pluralityof legs 36, a pair of clear condition, is withdrawn by way of conduit 44. parallel rings 37 and 38 and a plurality of cylindrical Examples of refinery runs and results obtained by staves 39. These staves are parallel and spaced from treating hydrocarbon oils in accordance with this inveneach other and from staves 34. Staves 34 and 39-. are tion and employing systems of apparatus, as above desimilar in configuration and relative position to the correscribed, are set forth in the following tables:

Run No 1 2 a 4 a V 5 6 Duration of Run in Hours 2 .75 2 2 2.25 3. Charge Stock Eastern Vene- Eastern Yene- Southern Lou- Kuwait Virgin Untreated Western Venezuela Virgin zuela V1rginisiana Virgin Oil. Catalytic zuela Virgin Oil. 011. 011. Cracked Oil. Oil. Temperature oi Stock in Treating ZoneinF. 10 1 99. 04, 108 109 108.

a b ab a b a b a b a (2 Moisture Content of ChargeStock in ppm... 174 236 103 253 88 91" 172 613 233 464 120 194 Moisture Content of Product in p.p.m 104 105 67 86 62 63 148. 148 96 128 61 66 Moisture Removed in p.p.m- 70 13 36 167. 26 28 24 465 137 336 59 128 Weight Percent of Water Removed 40.2 55.5 35.0 66.0' 29.5 30.8 14.0 75.9 5&8 72.5 49.2 66.0

In the table P. p. m. denotes parts of moisture per million parts of oil, a refers to composite specimens. 7) refers to averages of specimens taken at the start, middle and end of the corresponding run.

spending staves disclosed in Fagergren Patent 1,963,122, to which reference may be had for further details, of construction.

An imperforate tubular air chamber 40- is positioned between stator ring 37 and plate 17. Air from the atmosphere is admitted into the rotor by way of the spaces between members 23, opening 22 in plate 21 opening 18 in plate 17, the interior of air chamber 40v and openings 31 in spider 28, in the order named.

As is shown in Fig. 1, feed conduit 10 extends downwardly along the side wall of tank 15 and thence along the bottom wall of that tank, terminating at stator 35,

whereby to discharge oil to be treated in the, region directly below rotor 26. Also, water discharge conduit "l he solubility of water in hydrocarbon oil is commonly known as thehaze point of the oil. This varies with 8 communicates with the interior of tank '15 andv is pro vided with a control valve 41 for withdrawingaccumulated water from this tank, as required.

A spillway 42 (Fig. 1) is secured to tank 15 and empties into a suitable receptacle, such as a sump tank 43, which receives foam and, treated liquid from the upper portion of tank 15. Treatedoil is withdrawn from tank 43 by a conduit 44.

For the purpose of briefly outlining themode, of opera:

tion of the above described system of apparatus, it is first assumed that oil, which does not contain an appre: ciable quantity of free water, is being transmitted by feed conduit 10 to the region of tank 15 below rotor 26, and that driving unit 20 is in active service, thereby irr parting rotation to the rotor. The oil moves upwardly into the rotor through rotor imparts vigorous stirring and agitation to the oil in the stator. Due to the rapid movementof the, oil in the rotor, a partial vacuum is created therein and air is inspirated into the rotor through the openings. earlier described. The air so admitted into the rotor is brought openings 33 in spider 29. The

into intimate contact with the oil and dispersed therein,

oil and air is moved outwardly, by,- centrifugal action the temperature of the oil. At the haze point tempera ture' of 0 F., hydrocarbon oils normally contain about 10 parts of moisture per million parts of oil; at haze point temperature of 30 F parts of moisture; and at haze point temperature of 50 F;, parts of moisture. A haze point temperature of- 30" F. is considered excellent, while one of- 50 F. is considered satisfactory.

The extent of moisture removal by the practice of this invention is dependent on a number of factors, including the characteristics of the particular; composition undergoingtreatment, the temperature of the composition during treatment, the rate of flow, the size and. design of the treating zone and of the rotor-stator unit, the speedof rotation of the rotor and the amount of airintroduced into the composition. The refinery runs identified in the foregoing tables employed a tank, corresponding'to tank 15, that was 18" wide, 23" long and 14" deep, a driving unit having a horsepower, explosion-proof, electric motor operating at a speed of 1750 R. P. M., and a rotorstatorunit approximately 7" wide. The referred to charge stocks were continuously introduced into tank 15 at a rate of from 2 to 4 gallons per minute, depending onthe particular stock, and were successfully dehazed at treating temperatures of from 99 to 118 F.

Treating equipment having a considerably greater capacity than that just described has also been used. to effectively and economically dehaze oils in accordance with this invention. One arrangement of such equipment includes a treating tank, corresponding to tank 15, which is 66 wide, 84" long and 38" deep, a driving unit having a 15 horsepower, explosion-proof, electric motor operating at a speed of 490 R. P. M., and a rotor-stator unit approximately 24" wide, Tests have demonstrated that this equipment adequately dehazes oil at the rate of from 200 to .500 barrels per hour depending on the type and, characteristics of, the parti ular oil; and its temperature;

during treatment. For example, No. 2 heating oil having a heavy moisture cloud was transmitted into this equip ment at a rate of 450 barrels per hour and effectively dehazed at a temperature of about 118 F. to obtain a bright, clear product. Also, a light lubricating oil was satisfactorily dehazed when run through the equipment at the rate of from 200-300 barrels per hour and at a treating temperature below its flash point and within the range discussed earlier herein.

From the foregoing, it is believed that the method and apparatus for practicing the instant invention will be readily comprehended by persons skilled in the art. It is to be clearly understood, however, that various changes in the apparatus herewith shown and described and in the method of practicing the invention, outlined above, may be resorted to without departing from the spirit of the invention as defined by the appended claims.

What is claimed is:

1. In a method for removing moisture occluded in a substantially water immiscible liquid composition which is substantially free from water readily separable by gravity, the steps of (1) agitating said moisture containing liquid composition in the presence of gas to which said liquid composition is chemically substantially inert at the operating temperature to form an intimate mixture of said liquid composition with dispersed gas in the form of fine bubbles and cause repeated expansions and contractions in the mixture thereby contacting and evaporating occluded moisture into the dispersed bubbles of gas, (2) separating the dispersed gas carrying absorbed moisture from the unevaporated constituents in the mixture and (3) recovering all of the unevaporated constituents which constitute the relatively water-free water immiscible liquid product.

2. The method according to claim 1, in which the substantially water immiscible liquid composition is a liquid hydrocarbon oil composition, the gas is air, and the operation is conducted at a temperature below the flash point of said oil composition.

3. The method according to claim 1, in which the substantially water immiscible liquid composition is a liquid hydrocarbon oil composition, the gas is air drawn in from the surrounding atmosphere, and the operation is conducted at a temperature below the flash point of said oil composition and within a temperature range of to F.

4. In apparatus for removing occluded Water from a water immiscible liquid free from water readily separable by gravity, a tank, means for continuously introducing the liquid to be treated at a predetermined rate into said tank near the bottom thereof, agitating means and associated baflle means for defining and maintaining a treating zone of violent agitation and turbulence in said tank substantially above the bottom and substantially below the top thereof, means associated with said agitating means for drawing into said zone of agitation and turbulence the liquid to be treated and a gas in order to form an intimate turbulent mixture of said liquid and finely dispersed gas, a relatively quiescent zone in said tank into which said mixture of treated liquid and finely dispersed gas can flow from said zone of agitation and turbulence and rise by gravity to the top of said tank, thereby allowing at least some of the dispersed gas to separate from the treated liquid by gravity, and means connected near the top of said tank by means of which the mixture of treated liquid and remaining gas continuously overflows to a receptacle wherein the remaining gas admixed therewith can separate by gravity and all unevaporated constituents of the treated liquid can be recovered.

References Cited in the file of this patent UNITED STATES PATENTS 2,220,574 Little et a1 Nov. 5, 1940 2,274,658 Booth Mar. 3, 1942 2,342,024 Walker Feb. 15, 1944 2,436,375 Booth et al Feb. 24, 1948 2,451,144 Aubrey Oct. 12, 1948

Claims (1)

1. IN A METHOD FOR REMOVING MOISTURE OCCLUDED IN A SUBSTANTIALLY WATER IMMISCIBLE LIQUID COMPOSITION WHICH IS SUBSTANTIALLY FREE FROM WATER READILY SEPARABLE BY GRAVITY, THE STEPS OF (1) AGITATING SAID MOISTURE CONTAINING LIQUID COMPOSITION IN THE PRESENCE OF GAS TO WHICH SAID LIQUID COMPOSITION IS CHEMICALLY SUBSTANTIALLY INERT AT THE OPERATING TEMPERATURE TO FORM AN INTIMATE MIXTURE OF SAID LIQUID COMPOSTION WITH DISPERSED GAS IN THE FORM OF FINE BUBBLES AND CAUSE REPEATED EXPANSIONS AND CONTRACTIONS IN THE MIXTURE THEREBY CONTACTING SAID EVAPORATING

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