US3318448A - Fluid separating and cleaning method and apparatus - Google Patents

Description

W. E. FRYER May 9, 1967 FLUID SEPARATING AND CLEANING METHOD AND APPARATUS Filed Sept. 6. 1963 .S Il. n

INVENTOR. ,c

. W NW @Q y r. l mw V.

Patented May 9, 1967 lice 3,318,448 FLUID SEPARATING AND CLEANING METHOD AND APPARATUS William E. Fryer, 1215 Louise Ave., Arcadia, Calif. 91006 Filed Sept. 6, 1963, Ser. No. 307,222 11 Claims. (Cl. 210-71) This invention relates to separating and cleaning apparatus and more particularly to an improved and simplitied continuously operable apparatus for the treatment of crude oil land the like and effective to remove gaseous, liquid and solid contaminants present therein as received from a producing well.

As is well known crude oil produced by an oil well is accompanied by numerous contaminants including gases, liquids and solids and desirably removed prior to transport of the crude oil to a refining station. There have been many prior proposals for dealing with this problem but all are subject to various objections, disadvantages and shortcomings sought to be obviated by the present invention. In general such prior proposals are characterized by the discontinuous nature of the operating cycle, and shutdown from time to time being essential to remove separated contaminants and for reconditioning the apparatus generally in an effort to restore it to elfective operation. The principal contaminants normally encountered are occluded gases, water, and solids including particles of foreign matter and, in particular sand. The sand constituent is particularly troublesome because of the difculty experienced in efforts to remove quantities settling out on interior surfaces of the treating equipment.

By the present invention there is provided a single unitary housing of elongated tubular configuration disposed generally horizontally and having its bottom wall surfaces converging downwardly into a collecting sump at an angle greater than the angle of repose for the solid particles precipitating from the lluid undergoing treatment. Suitable heating facilities, such as a steam heat exchanger, are disposed in the upper part of the separating shell and employed to maintain the uids at an appropriate elevated temperature productive of ecient separation of contaminants. Dirty crude enters near one end of the shell, ows through a circuitous passage provided by appropriate baffling with the clean oil overflowing the lip of a Weir located remotely from the point of entrance. Suitable control devices are provided for monitoring conditions within the separating shell and are operable, for example, to maintain a water level or interface between the water and the oil close to and preferably below the entrance level of the incoming crude oil. Other controls include automatic means for regulating the discharge of clean Voil, the back pressure in the gas collecting dome, the rate of crude oil entry and the control of the heat exchanger to maintain a desired temperature level in the crude oil layer.

YA particularly important feature believed principally responsible for the continuous operating capability of the present apparatus is the method employed for initiating operation of the equipment. Thus it is found that the eciency and effectiveness of the apparatus in continuous performance is assured by initially flooding the entire apparatus with water. Thereafter this water is brought up to the normal operating temperature of the :apparatus in any suitable way such as by use of the heat exchanger forming a part of the apparatus. Once this has been accomplished water is gradually replaced by admitting crude oil at the same rate the water is withdrawn from the lower portion of the shell. In consequence it is found that the interior surfaces of the apparatus wetted initially with water display no tendency for solid constitutents, such as sand present in the crude oil, to adhere to these surfaces. Furthermore, this ability of the previously wetted surfaces to continue to shed sand readily continues unabated and so long as the apparatus is maintained in operation. This aspect of the invention not only greatly increases the efficiency of the heat exchanger but it also assures self-shedding and continuous purging of the sand from the inclined bottom surfaces of the shell into the sand and water collecting sump.

A further highly signicant aspect of the referred-t0 preloading and preheating of the apparatus using water provides a high capacity heat storage capability for bringing the dirty fluid to be treated up to a desired optimum operating temperature substantially immediately and assures a minimum surface tension coefficient at the oil- Water interface thereby further adding to the efficiency and effectiveness of the separating operation initially and continuously throughout the duration of operation of the apparatus.

Another highly important aspect of the invention s the use of one of the reject uids, namely the Water, as a conveying vehicle for carrying away a less fluid separated contaminant such as sand and the like finely divided material. Not only is the water used to provide buoyancy for these solid particles but the ow of the water is further used as a transporting medium or vehicle therefor.

Accordingly, it is the primary object of the present invention to provide an improved apparatus and method for continuously separating contaminants fr'om crude oil and for conducting these various contaminants in separated form from the apparatus and for draining the clean Oil therefrom.

Another object of the invention is the provision of a simply and economically constructed apparatus for treating crude oil to separate out contaminants leaving clean oil to be -bled from another part of the apparatus.

Another object of the invention is the provision of a continuously operating mode of treating a mixture to separate out constituents thereof and utilizing a rejected one of the fluids as a medium for increasing the buoyancy of heavier rejected constituents and for carrying the same from the separating zone.

Another object of the invention is the provision of an improved mode of initiating operation of crude oil treating equipment involving preloading the equipment with hot water and utilizing the heat capacity of the latter quickly to bring crude oil to a proper separating temperature and thereby establishing and maintaining a minimum surface tension at the oil-Water interface throughout the uninterrupted operation of the equipment on a continuous basis.

Another object of the invention is the provision of a unique method for initiating operation of a crude oil treating apparatus and for so conditioning the same that sand and other solid contaminants do not adhere to its interior surfaces.

Another object of the invention is the provision of a continuously operating crude oil treating and separating device capable of operating for prolonged periods without shutdown and including automatic means for maintaining proper operating levels and conditions within the apparatus.

Vthe opposite sides of a the oil layer.

drawing in which a preferredV FIGURE 1 is a longitudinal cross-sectional view of a typical ing -apparatus according to the present invention.

FIGURE 2 is a cross-sectional view taken along line 2-2 on FIGURE l; and

FIGURE 3 is a cross-sectional view on an enlarged scale taken Yalong theV broken line 3-3 on FIGURE l.

Referring to FIGURE 1, there is shown a Vpreferred embodiment of :a dirty uid treating apparatus designated generally 10. The apparatus has an elongated generally tubular main body shell 11 closed at its opposite ends. A Vfeature of the main body shell is the provision of downwardly converging bottom walls 12, 12 opening into a tubular waterV and sand collecting sump 13. The bottom of the latter also converges into a vertically-disposed outlet conduit 14 for conveying the sand Vand water toa point of disposal through a regulat'able flow valve 15. Of importance is the fact that the angle of inclination of bottom 12 is somewhat in excess of the angle of repose of submerged sand and other solid materials settling out of the uids undergoing treatment in the separator. By reason of this design the solid contaminants are continuously self-draining under gravity along the inclined bottom into the centrally-disposed collecting sump 13.

The upper portion of the main body of the shell is provided with a suitable heat exchanger such as a plurality ofrhairpin- shaped tubes 18, 18 having their opposite ends disposed adjacent one another and Welded or otherwise suitably secured in openings in a header 19 on partition wall 38. Tubes 18 are preferably provided with ns 20 for increasing theV heat exchangeV capability of the tubes through which any suitable heating medium, such as steam, may be supplied by and preferred embodiment of a crude oil treat- Y way of inlet conduit 22 and carried away through an out- Y let conduit 23. n

In a preferred arrangement internal partitions and baffle means are provided in at least that portion of entrance half ofthe main separating chamber occupied by Such baflie means indicated at 25 project alternately from the opposite sides of the shell and each includes a bae portion 25a pierced by the heat exchange tubes'18, and a separate and additional portion 25b emc bracing the sides ofthe tube bundle and positioned to supplement portion 25a,inrblocking oil ow between the shell Wall and the outer rim edge of portion 25a, in a manner best Vshown in FIG. 2. Y

A Weir 28 extends across the outlet end of theseparator with its upper Vedge 29 terminating somewhat below the top Vwall -of the-shell. AV supporting bracket 30 ex- ',tends crosswise ,of the shell and aids in supporting the Y reverse bend end of heat exchanger tubes 18. YClean oilV overowingweir lip 29 collects in chamber 32 and is withdrawn through Aan outlet conduit 33 having a regulatable control valve 34.

CrudeV oil containing contaminants enters shell 11 by way of conduit 35 at the Yendrthereof remote h'om Weir 28 and ata level even with or slightly below the wateroil interface 37. The rate of crude oil inow is preferably regulated by Vany suitableV flow rate control device 39 having a control connection 40 to valve 36 and operating in known manner to maintain a substantially uniform ow of contaminated crude oil into the apparatus.

Maintenance of a desired uniform operating temperature in the oil-flooded portion of thev separator is provided by a temperature sensing thermostat 42 submerged in the oil near Weir lip 29 and connected by a control line V43 with a steam ow regulating valve 44 located in steam inlet pipe 22.

erally tubular main housing 46. This housing has a conf neetion 47 in communication with the water layer existing below interface 37 anda second tubular connection 48 with the oil layer overlying this interface. It will be apparent from FIG. 3 that the same interfaceY level 37 exists in housing 46 as within shell 37. VThe dual-gravity interface sensing float and partly in the water layers and is connected'by an actuator 50 with known valve controller mechanism located in housing 51 and having Van operating connection through line 52 with the water and sand ow control valve 15. change in the level of interface 37 from a predetermined level is effective throughY connection 52 to conveyora corrective regulating signal to valve 15. Thus if the interface level rises valve 15 is opened slightlyto increase the water withdrawal rate and the converse is true if the interface level tends to fall below the predetermined value.

Another ow regulator is connectedt-o the clean oil dis- Y' charge from shell 15 and includes a iloat housingSS having connections 56 with the shell on the opposite sides of the clean -oil level `57. A oat 58 parti-ally submerged V Y in the oil operates a corrective 59 toV control the operation of this device is to assure a proper signal transmitting device liquid head of clean oil Ywithin the-chamber at all times as well as to provide a` liquid seal 4at the oil outlet to maintain a desired back pressure on the gasV collecting dome 60 for-med in the'upunder the control of a regulating valve `62 provided operating connection 64 with valve 62.

To place the described liquid treating and contaminant separator apparatus in operation, the operator floods and preloads the Ventire main body of the apparatus with water through water inlet valve 41 up to the top orrlip edge29 of Weir 28. Steam or other suitable heating medium Vis admitted to Vthe heat exchange tubes 18 Vand the entire `apparatus is brought up essentially to its normal operatingV temperature most 'appropriate for elfective operation-withv the particular type of crude oil being processed. ThisYYY having been done, the apparatus 1s in readiness to receive dirty `crude oil introduced through conduit 35 and regulating valve '36 therefor. As the oilY is admittecl`water is withdrawn at substantially-the same rate through valve 15. Y

It will be recognized from theforegoing thatV Vthe oil is quickly brought up to t-he'temperature ofthe water charging the apparatus and that the-apparatus thereafter operates with `a Vsubstantially constant interfacef level between the oil and gas, that is a level generally opposite the upper edge of weir lip 29. Owing Yto the fact that all interior surfaces ever in contact with theV crude oil are first wetted with Water Furthermore,'any foreign matter tending to settle on these surfaces is easilyrdetached whereas quite theV contrary is true if the metal surfaces are rst wetted with oil. v Furthermore, it is found that ,the inclinedbottom wallsof This control will be Y 49 Yis submerged partly in the oilY In consequence it will be understood that any valve 34. The object ofV this collecting dome .and is withgas outlet duct 61 with y a known type of pressure control regulator 63 having anV before being contacted with the oil, it is found that there is no tendency for sand or ,Y other foreign particles to cling to the metal surfaces.Y

flooded with i1-these.

lets operate as described above to maintain appropriate liquid levels despite considerable fluctuation in the quan- -tity of foreign contaminants present in the entering crude oil. The equipment is found to operate for prolonged 'and continuous periods with negligible supervision without need for shutdown for cleaning and reconditioning typically characteristic of prior crude oil treating equipment.

The apparatus operates with a minimum pressure drop between its inlet and outlet owing to the substantially open and unobstructed nature of its interior. The operating eciency is unusually high for various reasons vincluding the important fact that it is unnecessary to maintain the temperature of the very considerable quantity' of separated water present below interface 37. In other Words, once the water constituent gravitates below this interface it may be and preferably is allowed to cool to ambient temperature lwithout in anywise adversely affecting the operating etciency or effectiveness.

While the particular iluid separating and cleaning apparatus herein shown and disclosed in detail is fully capable of attaining the objects and providing the advantages hereinbefore stated, it is to be understood that it is merely illustrative of the presently preferred embodiment of the invention and that no limitations are intended to the details of construction or design herein shown other than as defined in the appended claims.

I claim:

1. A crude oil separator comprising 4a generally-tubular horizontally disposed main chamber having a bulbous extension projecting downwardly from said main chamber 'and having walls which converge into the top of a sand rand water receiving sump, said converging walls downwardly sloping at an angle in excess of the angle of repose of submerged sand precipiating from the crude oil undergoing treatment, heat exchange means in the upper portion of said main chamber connected to header means at one end of said m-ain chamber, a clean oil overow weir across the other end of said main chamber, means for maintaining said bulbous extension Hooded with water and maintaining an interface between oil in the upper portion of said main chamber and water in the lower portion thereof, said heat exchange means being disposed in said oil, means for introducing oil to ybe treated near said one end of the main chamber at a level closely spaced -to the interface between said oil in the upper portions of said chamber and the water iilling the lower portion thereof, and separate means for cond-ucting sand and water from said sump land clean oil from the downstream side of said Weir.

2. A continuously operating separator for treating freshly produced crude oil, said apparatus comprising -a generally horizontally disposed tubular shell having a downwardly converging -bottom on its underside opening into a sump, said bottom walls sloping at an angle in excess 0f the angle of repose of submerged sand precipitating from the crude oil undergoing treatment, valve means for maintaining the lower portion of said shell flooded with water, means for maintaining a body of crude loil substantially filling the upper portion of said shell and supported by otation on water ooding the lower portion of said shell to form an oil-water interface, heat exchange means positioned to be submerged in said oil, an overow weir for clean oil at one end of said shell, a level, controlled drain valve for oil on the downstream side of said Weir, means for withdrawing gas from the top portion of said shell, and said means for maintaining a body of oil in said shell including means for introducing crude oil to be treated near the oil-water interface and at the end of said shell remote from said Weir.

3. A crude oil separator as defined in claim 2 characterized in the provision of staggered batlle means projecting toward one another alternately from the opposite interior sides of said shell adjacent the crude oil inlet end of said shell and effective to cause the oil to How in a horizontal sinuous path from said oil inlet toward the Weir-equipped end of said shell.

`4. That improved method of continuously treating crude oil to separate out foreign constitutents including s-and and gas which comprises, initially ooding with water substantially all portions of a separator chamber of the type having a downwardly converging bottom and equipped with battled heat exchange means in its upper portion, passing a heating medium through said heat exchanger to heat said water to a predetermined temperature, introducing untreated crude oil near one end of said chamber adjacent the mid-height of said chamber while lowering the water level and forming an oil-water interface by withdrawing hot water from the bottom of said chamber at substantially the sa-me rate at which the oil is entering said chamber and While passing a heating medium through said heat exchanger, decreasing the rate of water Withdrawal as the water level drops to the midportion of the chamber so as to maintain a generally steady level `of the oilwater interface, skimming clean oil from the top of said chamber at the end thereof remote from the point of entry of untreated crude oil, draining separated sand by gravity across the bottom of said chamber into a sand and water collecting sump, and withdrawing sand and water from said sump..

5. -That method 'as dened in claim 4 characterized in that said chamber is generally tubular and disposed with its longer axis horizontal, and including the step of withdrawing gas from the top of said chamber and introducing crude oil to -be treated below the upper level of liquid in said chamber and at a level close to but above the oil-Water interface.

6. That method of placing crude oil separator -apparatus in operation initially which comprises ooding with water Val1 interior surfaces to be contacted by contaminated crude `oil to be subjected to cleaning treatment, heating said water to a temperature approximating normal operating temperature for said apparatus thereby assuring that the apparatus surfaces are rst wetted with hot water, and gradually introducing dirty oil to the upper portion of the apparatus to float the oil on said water and form an oil-water interface while lowering the water level by withdrawing water from the bottom portion at a rate coordinated with the rate of crude oil introduction until the oil-water interface between oil oating on the Water has fallen to the desired operating level for normal use of said apparatus.

7. That method defined in claim 6 characterized in causing said crude oil to flow in a general horizontal but tortuous path from a point adjacent one interior side thereof to a point of clean oil withdrawal remotely spaced from the point of contaminated oil entry.

'8. A continuously operating crude oil separator apparatus having an elongated tubular shell having walls and closed at its ends `and supported with its axis disposed horizontally, means for maintaining the lower portions of said shell Hooded with water and the upper portions thereof Iflooded with oil to form an oil-Water interface, -inned steam heating pipes extending horizontally through the top portion of said shell above the normally-prevailing oil-water interface `and connected with header means therefor in one end of the shell, clean oil skimming weir means -across the other end of said shell with its upper edge close to the top thereof, said shell having an oil and sand collecting sump and having upwardly diverging Walls merging at their upper portions thereof with the lower portion of the walls of said shell, said diverging walls sloping 'at an angle in excess of the angle of repose of submerged sand therein whereby substantially all sand settling out of said crude oil gravitates readily along said sloping walls directly int-o s-aid sump, and means for withdrawing oil and water from said sump.

9. Separator apparatus as defined in claim -8 characterized in the provision of dual-gravity float means submerged in prt in the water-dooded portions of said lapparatus and in part in oil-flooded portions thereof and V.connected with means controlling the oil-water interface level within said apparatus.

10. Separator apparatus as dened in claim 9 characterized in that said sand and water collecting sump is substantially centrally of said shell between the opposite ends thereof.

11. That method of preloading land initiating Ioperation of a crude oil cleaning, separating and treating apparatus which method comprises, preloading the apparatus with water to a level -corresponding substantially to the highest liquid level under normal operation to clean crude oil; bringing the water up to a VVdesired operating temperature for said apparatus thereby to wet the interior surfaces of the apparatus with hot water and to provide stored heat for quickly 'bringing crude oil to its intended separating temperature substantially as soon as it enters said apparatus thereby to lower the surface tension of the later 'formed oil-water interface, and withdrawing water from the lower portion of said apparatus to lower t-he initial water level to a normal water-operating level while introducing an equivalent volume of crude oil to be treated and forming said oil-water interface.

References Cited by the Examiner UNITED ll/l96l 4/1963 1/1964 STATES PATENTS Marsh 55-45 Gill 55-176 X Miller 210-187 X Millard 210-180 X Glasgow et al. 55-174 X Lovelady et al. 21-0-180 X Schoenfeld 210-187 X Glasgow 55-45 X Glasgow 55-175 Glasgow et al. 55-174 XV Great Britain.

REUBEN FRIEDMAN, Primary Examiner. D. M. RIESS, Assistant Examiner.

Claims (2)

1. 6. THAT METHOD OF PLACING CRUDE OIL SEPARATOR APPARATUS IN OPERATION INITIALLY WHICH COMPRISES FLOODING WITH WATER ALL INTERIOR SURFACES TO BE CONTACTED BY CONTAMINATED CRUDE OIL TO BE SUBJECTED TO CLEANING TREATMENT, HEATING SAID WATER TO A TEMPERATURE APPROXIMATING NORMAL OPERATING TEMPERATURE FOR SAID APPARATUS THEREBY ASSURING THAT THE APPARATUS SURFACES ARE FIRST WETTED WITH HOT WATER, AND GRADUALLY INTRODUCING DIRTY OIL TO THE UPPER PORTION OF THE APPARATUS TO FLOAT THE OIL ON SAID WATER AND FORM AN OIL-WATER INTERFACE WHILE LOWERING THE WATER LEVEL BY WITHDRAWING WATER FROM THE BOTTOM PORTION AT A RATE COORDINATED WITH THE RATE OF CRUDE OIL INTRODUCTION UNTIL THE OIL-WATER INTERFACE BETWEEN OIL FLOATING ON THE WATER HAS FALLEN TO THE DESIRED OPERATING LEVEL FOR NORMAL USE OF SAID APPARATUS.
2. 8. A CONTINUOUSLY OPERATING CRUDE OIL SEPARATOR APPARATUS HAVING AN ELONGATED TUBULAR SHELL HAVING WALLS AND CLOSED AT ITS ENDS AND SUPPORTED WITH ITS AXIS DISPOSED HORIZONTALLY, MEANS FOR MAINTAINING THE LOWER PORTIONS OF SAID SHELL FLOODED WITH WATER AND THE UPPER PORTIONS THEREOF FLOODED WITH OIL TO FORM AN OIL-WATER INTERFACE, FINNED STEAM HEATING PIPES EXTENDING HORIZONTALLY THROUGH THE TOP PORTION OF SAID SHELL ABOVE THE NORMALLY-PREVAILING OIL-WATER INTERFACE AND CONNECTED WITH HEADER MEANS THEREFOR IN ONE END OF THE SHELL, CLEAN OIL SKIMMING WEIR MEANS ACROSS THE OTHER END OF SAID SHELL WITH ITS UPPER EDGE CLOSE TO THE TOP THEREOF, SAID SHELL HAVING AN OIL AND SAND COLLECTING SUMP AND HAVING UPWARDLY DIVERGING WALLS MERGING AT THEIR UPPER PORTIONS THEREOF WITH THE LOWER PORTION OF THE WALLS OF SAID SHELL, SAID DIVERGING WALLS SLOPING AT AN ANGLE IN EXCESS OF THE ANGLE OF REPOSE OF SUBMERGED SAND THEREIN WHEREBY SUBSTANTIALLY ALL SAND SETTLING OUT OF SAID CRUDE OIL GRAVITATES READILY ALONG SAID SLOPING WALLS DIRECTLY INTO SAID SUMP, AND MEANS FOR WITHDRAWING OIL AND WATER FROM SAID SUMP.

Images