CA1332046C

CA1332046C - Centrifuge processor and liquid level control system

Info

Publication number: CA1332046C
Application number: CA000597304A
Authority: CA
Inventors: Jimmie Glenn Galloway Jr.; Lonny Ray Kelley; Mark Ernest Ehrhardt; Tracy A. Fowler
Original assignee: Exxon Production Research Co
Current assignee: ExxonMobil Upstream Research Co
Priority date: 1988-08-10
Filing date: 1989-04-20
Publication date: 1994-09-20
Anticipated expiration: 2011-09-20
Also published as: IT1231630B; FR2635472B1; DE3925355A1; GB2222101A; GB2222101B; JPH0268158A; GB8918246D0; DE3925355C2; NO893029D0; KR900002822A; US4846780A; AU3943389A; BR8903987A; IT8948160A0; NL8901173A; AU621143B2; NO175243B; NO175243C; FR2635472A1; MX166457B

Abstract

ABSTRACT

A centrifugal method and apparatus capable of separating a fluid stream composed of a plurality of components with differing specific gravities. The stream contemplated for separation is that of a producing oil well with components of oil, water, natural gas, and particulates. The method and apparatus use centrifugal forces to separate the gaseous, solid, and liquid components from each other. After separation is completed, detector and sensor arrangements are used to maintain liquid levels in the separator and to control the removal of the individual separated fluids from the apparatus.

Description

13~2~

r ;' CENTRIFUG~ PROCESSO% AND LI~UID LEVEL CONIROL SYSTEM

FIELD OF TNE INVENTION

The pre6ent invention relates to a method and apparatus for separating the components of a fluid stream comprising gas, liquit~, and solids. Specifically this invention refer~ to a oentrifugal type 6eparator and the control ~ystem employed to maintain proper fluid levels in the separator and to reduce impurities in each component discharged from the 6eparator.
Although thi6 invention will be discu6sed in the context of hydrocarbon production in the form of oil and gas, it iB
envisioned that the centrifuge method and apparatus m2y be used to separate any fluid stream with multiple components having more than one specific gravity.

BACKGROUND OF THE INVENTION

The initial separation of the numerous ~tream !
components contained in an oil or gas well stream is one of the most basic operation~ in the production of oil and ga6.
~ Typically, a hydrocarbon well stream contains numerous `~ component6, including natural gas, hydrocarbon liquids, produced ~ater, and particulates (6uch as sand). It i~ neces6ary to separate the6e four components before the oil and gas may be sold or used in the production operations.

,~ .

, . !

~L332Q~

Gra~ity ~eparation ve~sels are u6ually uset to separate the well stream component6. A typical production facility would include at least two such vessel6: a free-water knockout ves6el and a production separator. Both ve6sels have a ~teel 6hell with internal weirs and baffles. During production, the well tream would be produced through the free-water knockout vessel to remove a large portion, generally 602 - 90S, of the free water from the well 6tream. The production separator then further separate6 the remaining well stream componentfi of ga6, oil, and produced water into the ind~vidual components. The oil is discharged from the production separator to another vessel ; for additional treating for sale. The water from the protuction separator is discharged and sent to yet another vessel where the ~;~ small amount of oil that may hsve remainet in the water is removed. This treated water will then be handled as ~aste. The ga6 component also exit6 the production separator and i8 ~ent to a gas hantling facility where it will be treated for ~ale or u6e. Any sant producet will accumulate in the free-water knockout vessel and production 6eparator until these ves6els are removed from aervice and cleaned.

As i6 seen from this brie description, many pleces of eparation equipment are typically used in the protuction of oil and gas. Each piece is expensive to install, maintain, and operate-~`
.~ ~

13 3 ~

The weight and space requirement~ of the separationequipment i~ of particular concern for an offshore platform.
When offshore production facilities are mounted on platforms in ten~, hundreds, or even thousands of feet of water, ~pace is extremely expensive to provide. Reducing the size and weight of each piece of equipment can reduce the size of the offshore platform. It i8 on the offshore platform that thi6 present invention will be such a valuable piece of equipment. There i8 a need for a single, 6mall, relatively light weight piece of equipment which separates relatively large volumes of oil, gas, and water and which replaces the large, heavy, expensive, qessel6 used in the past.

Centrifugal equipment has been 6uggested for use in separating the multiple components of an oil or gas stream. In the typical arrangement the well stream fluids are introduced in the separator and rotated against the centrifuge wall. Layers of the individual components are formed with the specific gravities of the component layers decreasing as the distance from the wall increases. After separation i6 completed, the individual separated layers are then removed. This removal proces6 can be extremely difficult. As stated in U.S. Patent 3,791,575 (cl 1 ln 15-18~, the flow control of the discharge fluids from a centrifugal ~eparator presents a significant problem to the operation of a centrifuge. Various level control Rystems for centrifugal separators have been proposed to control the 10vels and the continuous separation of the inlet stream.
Examples of level control 6ystems include inlet controls as described in U.S. Patent 1,794,452; differential pressure controls as described in U.S. Patent 4,687,572; flow rate controls a& described in U.S. Patent 2,941,712; discharge fluid analysis as described in U.S. Patent 4,622,029; water ~; recirculation control as described in U.S. Patent 3,208,201; and an adjustable overflow weir control as described in U.S. Patent 4,175,040.
~ 10 Depending on the service efficiency required by a given centrifuge separator, the above described centrifuges and their respective fluid level control systems can be effective and - ~ adequate. The principal disadvantage with the centrifugal sy6tems di6closed in the past is their inability to obtain es6entially complete separation of the well stream components.
` A partial separation of fluids is often not acceptable.
;
In an offshore oil and gas operation where produced water will be disposed by placing the produced water back into the body of water where the platform i6 located, it is desirable that nearly no oil (u~ually less than 50 parts per million) be contained in the disposed water.
' ~

In an onshore operation, such complete ~eparation is also desirsble where produced water is disposed through disposal or injection wells. If oil iB contained in water that i6 .

~5~ 13320~

injected into a disposal well, the oil will eventually plug the formation and will require workover expenses to regain water di6posal or injection capabilities.

The pre6ent centrifuge and level control system i8 intendet to reliably separate the oil, gas, water, and sand component6 of a well 6tream.

SUMMARY OF THE INVENTION

This present invention is a centrifuge method and apparatus for separating the components of a stream comprised of a plurality of fluids having different specific gravities. Thi8 invention is characterized by the highly efficient, continuous 6eparation of a well stream containing oil, water, gas, and ~ome smaller volume of sand or other particulates by a single piece of equipment. The separation of the stream phases i~
accomplished by the use of a rotor, a fluid layer detection and sensor arrangement, and fluid removal 6COOp8 .

In the basic embodiment of the centrifuge processor, a rotor capable of rotating about its rotational axis, receives a fluid ~tream which is accelerated to the rotor wall. Any gas pre6ent in the inlet stream will separate from the liquids upon entering the rotor. The gas will then exit the centrifuge through a ga~ scoop whose passage opening will be controlled by a pressure regulator which will allow ga6 to flow from the centrifuge wben a specified pressure is reached. After the -6- 13320~

fluids have reached the rotor wall, they travel along the wall where they are 6eparated into their individual component6, with the higher specific gravity fluid (water) forming a fluid layer next to the liner and the lower specific gravity fluid (oil~
forming a fluid layer on the higher specific gravity fluid.
When the fluid reaches the oppo~ite end of the rotor from where it was fed, the streams have separated into their individual components. The oil layer then flows over a weir and into an oil fluid retention chamber. When the oil level in thi6 chamber reaches a specified height, a level control system utilizing a detector arrangement and a caged rotating float will open a flow passage from the oil fluid retention chamber and allow the oil to exit the centrifuge. The water will then flow into a water fluid retention chamber. When the water level in this chamber ;~ 15 reaches a specified height, a level control system utilizing a ~ ~second detector arrangement and a second, caged rotating float :, :
will open a flow passage from the water fluid retention chamber and allow the water to exit the centrifuge.

If it is anticipated that the well stream will contain sand or other solid particles, a second embodiment of the centrifuge proce~sor would be used. The 6econd embodiment would include a second, smaller rotor that would be mounted in6ide the rotor mentioned in the ba6ic embotiment. The well stream would be accelerated first i~ the ~econt, smaller rotor with any sand or other 601ids in the well stream being moved to the edge of ~- this ~econd rotor and removed through a sand/water 6COOp. 'rhe remaining well stream fluids will flow out of the second smaller rotor onto the impeller and into the main rotor and separated as described in the first embodiment above.

_7_ 1332046 Other additional element~ to further the efficiency of the centrifuge geparator are also described herein.

DESCRIPTION OF THE DRAWINGS

FIGURE 1 is an elevation view, partly in section, of a fir6t e0bodiment of the centrifuge processor.
:
FIGURE 2 is an elevation view, partly in section, of a ~econd embodiment of the centrifuge processor.

FIGURE 3A is a cross-sectional view of an acceleration impeller.

FIGURE 3B is a plan view of an acceleration impeller.

~- FIGURE 4 i6 a ~chematic of the control system for fluid removal.

FIGURE 5 is a plan view, partly in section, of a ,: ,, , I .
sand/water 6coop and agitator.

FIGURE 6 is an elevation view, partly in section, of still another embodiment of the centrifuge processor.

-8- 13320~fi DESCRIPTION OF THE PREFE M ED EMBODIMENTS

As seen in FIGURE 1, centrifuge 10 is composed of a cylindrical shaped rotor 12 capable of rotating around ~tstionary centerpo6t 14. High speed electric motor 16, or other hi8h speed device, rotate6 rotor 12 around centerpo6t 14 at rates of 6peed adequate to separate the different specific gravity fluid components in the inlet well 6tream. Rotor 12 i~
enca6ed by 6tationary, protective containment vessel 18 standing on leg6 ~0. Although FIGURE 1 shows centrifuge 10 in an upright poaition on legs 20, centrifuge 10 may be operatet in any ~; position. The gravity forces in centrifuge 10 exerted on the fluids being separated, as will be discussed later, are of a very small force relative to the large centrifugal force exerted on the fluid by the rotational motion of rotcr 12. Accordingly, centrifuge 10 may be operated with the rotational axis of rotor 12 (i.e. centerpost 14) in a vertical, horizontal, or any other directional orientation. Also, since centrifuge 10 can be ~ounted to a column or any other stable structure, legs 20 are not e66ential to the con6truction of the centrifuge.
, High speed electric motor 16 i6 connected by coupling 22 to driveshaft 24, which extends into protective containment vessel 18 through opening 26. Driveshaft 24 attache6 to bottom end cap 28 of rotor 12. Rotor 12 ~8 aligned inside protective coDtainme~t vessel 18 b~ lower bearing 30 around driveshaft 24 and by upper bearing 32. Thi~ alignment allow~ rutor 12 to ~;
9 133204~

rotate concentrically about centerpo~t 14 without touching protective containment vessel 18. Becau6e of the significant amount of kinetic energy rotor 12 has during operation, protective containment ve6sel 18 should be con6tructed to withstand the damaging effect6 in the event of a failure of the rotating part6 of centrifuge 10 and to ensure safe operation.
Lower 6eal 34 i8 u6ed to keep fluids that may have leaked from rotor 12 from exiting protective containment vessel 18.

In the preferred embodiment, centerpo6t 14 extends through opening 36 of protective containment ve66el 18. Between centerpo~t 14 and protective containment ve6sel 18 i~ upper 6eal 38 which prevents fluid leakage from protective containment ves~el 18 into the atmo6phere or other medium surrounding protective containment vessel 18. Centerpost 14 also extend&
through opening 40 in top end cap 42 of rotor 12 and down through the interior of rotor 12. Pre66ure 6eal 44 also prevent6 leakage from rotor 12 into protective containment ves6el 18. A centerpo6t i6 not required to ex~end the entire length of rotor 12 a6 6hown in FIGURE 1. Centerpo6t 14, a6 6hown, serve6 a6 an effective method to centrally locate ~nd support neces6ary flow passages and control line~ from the ~: centrifuge interior to the outside of rotor 12 and out through protective containment vessel 18. Other method6, such a~
$~div~dually extended flow line pas6ages, may also be used to locate and support such flow passage~ and control line6.

-lO- 13320~

In thi6 embodiment, centerpo6t 14 is hollow This allows feed and exit flow passage6 and control ~ensing lines to be run through centerpo~t 14 and into the center of rotor 12.
Fluid stream feed flange 46 allows fluid input into rotor 12 through inlet pas6age tube 48 which extend6 through centerpost 14 and out through fluid feed nozzle 50. Fluid feed nozzle 50 extends out of centerpost 14 into accelerator bowl 51 and near feed accelerator impeller 52. Accelerator bowl 51 and feed acceleration impeller 52 are mounted in6ide rotor 12 for rotation with rotor 12.

FIGURES 3A and 3B show side and plan views, respectively, of acceleration impeller 52. The function of acceleration impeller 52 is to efficiently move the fluid6 entering rotor 12 from no rotational motion to a rotational motion adeguate ~o achieve separation. In order to save space : and material requirements, it i6 de6ireable to achieve thi6 acceleration of fluids in as small a portion of rotor 12 as possible. Thi8 i6 accomplished by vanes 55 in impeller 52 which help pre~ent slippage of the fluid on impeller 52. Referring back to FIGURE 1, opening 53 i8 formed between centerpost 14 and acceleration bowl 51 to allow the passage of gas from acceleration bowl 51 into main opening 57 of centrifuge 10.

Also mounted i.nside rotor 12 is liner 54 which extend6 nearly the entire length of rotor 12. Small fluid flow pa~age 56 i8 formed by the space between the inner surface of rotor 12 and liner 54. Liner 54 is attached through spacer6 59 to rotor -11- 133204~

12 for rotation with rotor 12. As the liquid6 move off of acceleration impeller 52 and begin rotating on the inner 6urface of liner 54, the liquids separate into their different component6. In a typical well 6tream, these different S co~ponents are a lighter fluid ~oil) and a heavier fluid (water). The heavier fluid will form a fluid layer on liner 54 and the lighter fluid will form a fluid layer on the heavier fluid layer. Mountet on liner 54 i8 liquid level float cage 58 which houses liquid level float 60. Liquid level float cage 58 i6 attached to liner 54 for rotation with rotor 12. A6 the liquids and float 60 rotate on liner 54, there i6 no relative rotational movement between the liquids and liquid level float 60. Liquid level float 60 has a 6pecific gravity less than the lighter fluid and therefore floats on the lighter fluid layer surface. Float 60 is mounted within float cage 58 80 that it will move radially in or out toward the center of the rotor as the lighter fluid layer surface thickness increases or decreases.

A second liquid level float, liquid level float 62, is also cage mounted within a 6econd cage, liquid level float cage 64, to detect slight radial movement on the interface between the heavier fluid and the lighter fluid. Liquid level float 62, in order to float on the fluid interface between the heavy fluid layer and the light fluid layer, has a cpecific ~ravity between the ~pecific gravity of these two fluid6. Typically, the 6pecific gr~vity of a crude oil will be approximately 0.80 and of produced brine water approximstely 1.05. Therefore, liquid -12- 133204~

level float 62 would have a specific gravity between about 0.80 and about 1.05. Float cage 64 is also mounted to liner 54 for rotation with rotor 12. Accordingly, there is no relative rotational movement between float 62 and the fluids during operation of rotor 12. The locations of the floats and float cages may be anywhere along liner 54.

Although the preferred embodiment describes a fluid level detector system utilizing a float arrangement, any detector 6ystem capable of detecting the thickness of the lighter and heavier fluid layers and the locations of the interfaces could be incorporated to replace the float arrangement. Also, tests with the centrifuge apparatus have shown that the liner, which reverses flow and increases the separation time for the water, is not critical to separation;
however, the most efficient separation is achieved with the liner in place.

Along a~d anderneath liner 54 is mounted coalescing mesh 66, which is used to aRsist in the formation of larger droplets of the lighter fluid during the separation phase. By formiag larger droplets of the lighter fluid, the separation of the fluids occurs much more rapidly and efficiently. Coalescing mesh 66 also helps in maintaining the rotation speed of the fluiLds in rotor 12 by preventing slippage between the heavier fluid and the rotor wall. In the preferred embodiment a crushed polyethlyene matting is used to form an effective and ea~y to make coalescing mesh 66 Mesh 66 ~ay also be formed from expanded metal or be replaced by vanes, spikes, or any other material or surface thal: provides contact areas for the formation of larger oil droplets.

~ `

At one end of rotor 12, oil retention chamber 68 i8 formet by a plate 70 which i6 attached to the inside of rotor 12 for rotation with rotor 12. The front of chamber 68 i6 formed by weir 72 and plate 74. The back of chamber 68 is formed by the in6ide face of bottom end cap 28. When enough oil accumulates in rotor 12, it will spill over weir 72 through openings 73, which are behind weir 72, and will flow into chamber 68. Inside chamber 68 are vaneæ 76 and vanes 78 which maintain and assist the fluit rotation in chamber 68. Vane~ 76 and 78 are also connected to and rotate with rotor 12. Each of the pieces (plate 70, weir 72, and plate 74) that form oil retention chamber 68 and vane~ 76 and 78 rotate with rotor 12.
These components may be individually connected to rotor 12 or assembled and collectively connected to rotor 12.

Fluid 6coop 80 and fluid scoop 82 extend into chamber 68 from centerpost 14. The use of fluid Rcoops to remove fluid from a centrifuge i6 well known to those skilled in the art and doe6 not require any further di~cu6sion here. Fluid scoop 80 and fluid scoop 82 connect to flow pas~age 84 that extends through centerpo~t 14 and out through valve 86. Valve 86 i~
actuated by a valve operator 88. Valve operator 88 receives from ~ignal controller 92 a control signal through control line ~90. Signal controller 92 is a typical controlling device that `~25 receive6 an indicating signal from a ~ensing element, compare~
it to the set level, and produces an output control signal to achieve a desired control function. ~ere, signal controller 92 -14- 1 ~ 3 2 0 receives its indicating signal through control line 94 from po6ition sensor 96 that is mounted to centerpo6t 14. Position sen60r 96 detects the relative position of rotating float 60 to determine the position of the oil layer 6urface.

Signal controller 92 receives operating energy, 6uch a6 electric, pnuematic, or hydraulic, from source 98. Po6ition ~en60r 96 may use magnetic, optic, electric, ultra60nic or any other available sensing method to determine the relative po6ition of float 60. This embodiment uses an electronic pulse 6ensor. Signal controller 92 is capable of receiving an electronic pulse 6ignal generated by po6ition sensor 96 as it responds to rotating float 60. Sensor 96 may be arranged so that as the float moves further from liner 54 (and closer to position sensor 96), the signal from the sensor would increase or vi6a versa. In the first case, for example, as rotating ` float 60 ves further from liner 54 indicating an increase in oil in rotor 12, controller 92 would receive an electronic pulse signal from po6ition sen60r 96 and compare the ~ignal to its ~et point. When necec6ary to control valve 86, signal controller 92 would produce an output fiignal (typical output signals are in the form of an electrical 4-20 milliampere signal) to valve operator 88 through control l~ne 90 to open valve B6 to allow oil to be discharged from rotor 12. As oil is di6charged and the level goes down, 6ensor 96 would relay to controller 92 that enough oil ha~ left rotor 12 and the proper oil level has been reachet and that valve 86 shoult be clofied. As more oil enters the centrifuge, the cycle would be repeated.

- \ l ~33~6 Beneath weir 72 and plate 70 i~ flow pas~age 100 for the higher ~pecific gravity fluid. Flow passage 100 i8 formed between plate 70 and the inner surface of the lower end of liner 54. Water flows through pa6sage 100, reverses direction~, and S flowi through passage 56, which i6 formed by the outer surface of liner 54 and the inside 6urface of rotor 12. Near the upper end of pas6age 56 iR spillover port 102 that connect6 pas~age 56 to fluid retention chamber 104. The lower end of chamber 104 i6 formed by plate 105 that i~ attached to liner 54 for rotation with rotor 12. The upper end of chamber 104 is formed by plate ~ 107 also mounted for rotation with rotor 12. Any oil that did ; ~ not flow over weir 72 and into chamber 68 and that instead went through flow pa6sage 100 into pa6sage 56, will be forced into chamber 104 for removal by fluid 8COOp 106 which extends into chamber 104. Fluid scoop 106 connect6 to flow passage 108 which : connects and empties into fluid feed flow no~zle 48 for :' recirculation of this oil that reached the water removal area.
Above spillover port 102, near the in~ide wall of rotor 12, is ~: flow passage 110 through which water flow~ to water retention cham~er 112. The lower end of chamber 112 i~ formed by plate , ~ I
107. The upper end of chamber 112 i8 formed by the inside face of top end cap 42. Inside chamber 112 are vane~ 114 and vanes 116 which maintain and a6sist the fluid rotation in chamber 112. Vanes 114 and 116 are connected to and rotate with rotor 12. Like oil retention chamber 68, the pieces forming water retention chamber 112 may be individual components connected d~rectly to rotor 12 or can be as6embled and collectively connected to rotor 12.

Fluid 8COOp 118 extends into chamber 112 and connects to flow pa66age 120 which extend~ through centerpost 14 and out through valve 122. Valve 122 is actuated by valve operator 124.
Valve operator 124 receive~ from 6ignal controller 128, a control 6ignal through control line 126. The operation of controller 128 i6 gimilar to the operation controller 92 a6 previously discu66ed. Controller 128 receive6 its indicating 6ignal through control line 130 from po~ition sensor 132 that is mounted to centerpost 14. Signal controller 128 receives operating energy from source 134. Position sensor 132 detects the relative po6ition of float 62 to determine the water layer thickness. The operation of position sensor 132 is similar to the operation of position sensor 96 as previously discus6ed. FIGURE 4 shows a simplified control system for the level control ~ystem described above.

Near accelerator bowl 51 is ga6 8COOp 136. Mounted on accelerator bowl 51 are gas accelerator vanes 137. Vanes 137 assist in removing any small liquid troplets that may be entrained in the gas phase before the ga~ enters ga~ scoop 136.
Ga6 scoop 136 i~ attached to gas flow passage 138 that extends through centerpost 14 and out through valve 140. Valve 140 is a pressure regulat~ng valve that is actuated by valve operator 142 to maintain a preset internal pressure on the interior of rotor 12.

FIGURE 2 shows a second embodiment of rotor 12 and it~
level control system. 'rhis second embodiment has the capabilities of the firl3t embodiment and can additionally remove -17- 1332~46 particulates from the production stream. FIGURE 2 has bafiically the same component~ as FIGURE 1, but also contains an inner rotor asisembly 200. The inner rotor assembly 200 comprises an inner rotor 202, clean water feed nozzle 204, sand/water i~COOp 206, 8and/water flow line 208, and clean water flow line 210. In the second embodiment, fluid feed nozzle 50 is positioned to feed the production 6tream into the inner rotor as6embly 20Q. Opening 55 is formet between centerpost 14 and inner rotor assembly 200 which allows the passage of gas from inner rotor 202 into main opening 57 of centrifuge 10.

The primary function of inner rotor assembly 200 is to eparate and remove sand particles from the inlet production ;~ stream. Inner rotor 202 is attached feed accelerator impeller 52 and liner 54 for rotation with rotor 12. Sand/water scoop 206 extends from centerpost 14 into inner rotor 202. Clean water feed nozzle 204 also extends into inner rotor 202 from centerpost 14. The sand/water mixture picked up by 8COOp 206 is discharged out through flow passage 208 that runs up centerpost 14 and out of rotor 12 through orifice 212.
1 i 'I ' i FIGURE 5 shows a sand/water scoop 206 in greater detail. As seen in FIGURE 5, 8COOp 206 has a protruding fluid nozzle 219 that connects to passage 220 through scoop 206 to oponing 221. Nozzle 219 directs water in rotor 202 through passage 220 and out opening 221 to agitate the sand next to the rotor wall and help it move into 5COOp 206 and out through flow pa~sage 208. The outer end of 8COOp 206 which is close~t to inner rotor 202, becau~e of the erosional effect6 of the oand impinging on 8COOp 206, preferably include6 an ero~ion re6istant surface covering 222. It ha6 been found that a msn-made diamond plate i~ effective in reducing this ero~ion. ~owever, sny ero6ion resi6tant material may be u6ed. Orifice 212 may be an adju6table needle valve or a positive choke to control the rate that the sand/water mixture lea~es the inner rotor a66embly 200.
Attached to water feed no~zle 204 i6 clean water flow passage 210 that extend6 through centerpost 14. Clean water flow pa6sage 210 ha6 orifice 214 to control the rate o clean water introduction through clean water feed nozzle 204.

IN OPERATION

15The operation of the centrifuge and the liquid level ~ control sy6tem will now be discussed with reference to FIGURE 1.

`~ High speed electric motor 16 i6 engaged to rapidly turn drive shaft 24 through coupling 22. Drive shaft 24 6pin~ rotor 12 around stationary centerpo6t 14 in6ide protective containment 1 .
vessel 18. The rotational speed required to achieve adequate aeparation of well stream components will be dependent on the diameter sf rotor 12. If rotor 12 has a large diameter, the - rotational 6peed to achieve 6eparation will be smaller than the rotational speed required of a 6maller diameter rotor 12. For effective separation it i6 desirable to rotate rotor 12 80 that the fluids eYperience an centrifugal force of at lea6t 1000 times the accelerational force due to gravity (1000 g'6) along liner 54 and at the rotor wall. Rotor 12 i6 positioned by upper bearing 32 and lower bearing 30 to in6ure rotor 12 i6 centered in and does not contact protective containment ve6sel 18. Any fluit that may leak f rom rotor 12 is prevented f rom leaking f rom containment vessel 18 by lower seal 34 and upper seal 38. The fluid stream to be 6eparated is introduced through feed flange 46 into flow passage 48 and out of fluid feed nozzle 50 into accelerator bowl 51. Upon exiting fluid feed nozzle 50, the production stream fluid begin rotating in accelerator bowl 51.
A6 the fluid moves out of bowl 51, the fluid is further ;~ 10 accelerated along feed accelerator impeller 52 towards liner 54.
A6 the fluid reaches rotor 12 speed, the difference6 in the pecific gravities of the individual fluid components are magnified by the centrifugal force being exerted on the fluid components. AB it reaches liner 54, the fluid begin6 separating into layer6 of its various components by differing specific gravity. For a typical oil well stream containing crude oil and , ;, ~
brine water, thi~ would mean a water layer adjacent to liner 54 and an oil layer floating on the water layer with the two layers separated by an oil-water interface. In an effort to create equal fluid layer thickne6se6 along liner 54 and a6 the well stream i8 separated into it6 individual component6, the fluid layers begin flowing towards the other end of centrifuge 10 along liner 54. Coale6cing me6h 66 as6ists in the separation of the oil and water by helping to form larger oil droplets which increase6 the efficiency of the fluid separation. As the oil and ~ater flow through the coalescing section, the smaller oil droplet6 are provided contact surface6 that promote6 the formation of larger oil droplets. The larger droplets can then -20- 13320~

~ore easily move to the oil layer and out of the water layer.
The coalescing mesh also assists the oil and water fluid layerc to maintain ~ynchronous movement with the liner and rotor wall ~nd prevent any ~lip between the contacted centrifuge surface.
Coalescing mesh 66 also help6 reduce secondary fluid flows that can occur as the individual separated components move to the fluid removal chambers.

Before the thickness of the combined oil and water fluid layers on liner 54 reaches the height of weir 72, fluid flows through pa~age 100 and back along pa66age 56 between liner 54 and rotor 12. When passage 56 is filled and the combined fluid thicknes6 reacheæ weir 72, the centrifuge i8 filled to its operating fluid level. The two adjacent fluid layers must now be separated and removed from the rotor.
', .
The rotation of rotor 12 will establish two distinct layers on the inner surface of liner 54, one of oil and the other of water. The introduction into rotor 12 of additional oil and water will cause the spillage of oil over weir 72 into oil retention chamber 68 and water flow through flow passage llO
under liner 54 and on into water retention chamber 112. If enough oil is introduced, oil will flow over weir 72 and through openings 73 and begin filling retention chamber 68. As the chamber i8 filled~ the oil leve~ will ri6e above weir 72 ant cau8e vement of float 60 floating on the surface of the oil llquid layer inside of float cage 58. As the surface of the oil layer moves, position sensor 96 relays to controller 92 the -21- 133~0~6 relative movement of float 60 ant therefore neces6arily, the movement of the oil layer surface. When the signal corre6pond6 to a preset level in controller 92 indicating a 6pecific oil level height, controller 92 will initiate the neces6ary control cteps to remove oil from chamber 68.

Upon receiving the proper signal from po6ition ~en60r 96, controller 92 signals valve operator 88 through control line 90 to open valve 86 which will open flow passage 84. When flow pa66age 84 opens, the angular velocity of the fluid in the oil retention chamber 68 will be converted to dynamic pre66ure (similar to a centrifugal pump) and will force the oil into fluid scoop 80 and fluid ~coop 82 and out flow passage 84. As oil is being remoYed from centrifuge 10, the oil level in chamber 68 lS will be lowered which will cause float 60, in float cage 58, to .. . .
'b~' ~: be lowered. The position sensor and the control system will then ; close valve 86 until the oil level rises again to the preset ; ~ level and the emptying cycle i6 repeated. Valve 86 may use opening, cloRing, or throttling actions to maintain the proper oil level in rotor 12.
!

The water fluid layer, because of its higher 6pecific gravity, will be formed atjacent to liner 54. As more water i8 introduced into rotor 12, the water layer thickne6s increases.
As the water layer thickness increafie6, water will flow through flow pa~sage 100 under oil retention chamber 68, reverse directions, and flow back toward the other end of centrifuge rotor through passage 56, and through flow passage llO. This `
-22- 13320~6 water movement through flow pas6age 56, and on through pa66age 110 will cause water retention chamber 112 to fill. The filling of retention chamber 112 will cause the oil-water interface relative to liner 54 to ri~e. A~ the interface rises, interface float 62 in6ite float cage 64 will also ri~e and initiate a control sequence ~imilar to the oil level control ~y6tem previou61y di~cussed.

When the interface level reaches a certain, preset location, indicating a specified water layer thickneæ6, position ~en60r 132 will relay to controller 12X the need to remove water from fluid retention chamber 112. Controller 128 will then signal valve operator 124 through control line 126 to open valve 122 which will open flow passage 120. When flow passage 120 opens, the angular velocity of the fluid in retention chamber 112 will be converted to dynamic pressure and force the water into fluid 8COOp 118 and out flow passage 120. When enough water i8 : removed from the fluid retentîon chamber 112, the level of the oil water interface and, therefore, necessarily the distance of float 62 relative to liner 54 will decrease. Thi6 movement will be detected by 6ensor 132 and will ultimately re~ult in the shutting of valve 122 until another signal i6 received indicating the retention chamber is full which will initiate another water dump cycle. The action of valve 122, like that of valve 86, may be snap acting, on or off, or may be made to act as a throttling valve, in re6pon6e to the water layer fluid thickness. As the water travels toward fluid retention chamber 112 in flow pa66age 56 between liner 54 and rotor 12, it travelæ

-23- ~332~

through coalescing mesh 66. Mesh 66 assist~ in the formation of larger o~l droplets for any oil that may have not been removed through fluid retention chamber 68. Before any oil that entered flow pas~age 56 has reached fluid chamber 112, it will be forced next to the inside wall of liner 54 by it~ 6maller specific gravity. This oil, typically called ~kim oil, will then flow : along the inside wall of liner 54 with water through flow passage 102 into 1uid retention chamber 104. The mixture of oil and water that flows into chamber 104 i~ removed throu~h oil/water scoop 106 and placed back through flow pas~age 108 into flow passage 48 for reseparation. This recirculation method helps insure that no oil will reach the fluid retention chamber 112 and that no oil i6 discharget out the water flow passage 120.

During the operation of the centrifuge, it i8 de6irable for effective separation that the oil-water interface remain in a predetermined operating range above liner 54. The interface control system ~hould not allow the interface to rise above the height of weir 72 or fall to the level of flow pas~age 100. If the oil-water interface on liner 54 rises above the height of weir 72, water will flow over weir 72 and 8pill in retention chamber 68 and be removed by fluid scoop~ 80 and 82.
; Alternatively, if the oil-water interface on liner 54 falls to the level of flow passage 100, oil will flow through passsge lO0, back through pas~age 56, and potentially enter fluid cha~ber 112 and be removet through fluid 8COOp 118. Therefore it is necessary that the oil-water interface remain a tistance from ,1 , liner 54 that i8 le6s than the height of weir 72 from liner 54 and more than the distance from the top of flow passage 100 to liner 54, thereby preventing the oil phase from flowing through passage 100 snd preventing the water phase from flowing over weir 72.

The preceding description de6cribes method and apparatus for separating a well stream without a significant gas component. If the well stream contains a gas phase, the following occur~. The gas phase is introduced into rotor 12 with the liquids through inlet feed flange 46 and fluid feed nozzle 50. Because of the small density of gas relative to the liquids, the gas is separated from the liquids as it enters bowl 51 and migrates to main opening 57 of centrifuge 10 through opening 53.
As the water layer forms in rotor 12 and as the oil layer forms on the water layer, gas occupies main opening 57 of centrifuge 10 and forms a ga6-oil interface at the surface of the oil layer.
Gas acceleration vanes 137, which rotate with rotor 12, provide additional separation of any small fluid droplets that might ~till be entrained in the ga6 phase. Gas scoop 136 allows the gas to enter passage 138 in centerpost 14 and out rotor 12. Gas flow passage 138 i6 controlled by gas pre6sure regulating device 142 and valve 140. As more gas enters rotor 12~ the internal pressure of the sy~tem increasesO When the pressure reaches a designated pressure, pressure regulsting device 142 will open ~alve 140 and allow enough gas to exit the centrifuge to reduce the pressure inside the separator. Such pres~ure regulating device6 and vslves are well ~nown in the oil and gas production indu6try and do not need further di6cu6sion here. The fluid stream~ free of gas, exi~ts bowl 51 and i6 accelerated by feet accelerator impeller 52 to full rotor ~peed where it is separated as described above.

If sand or other particulate6 are expected to be produced in the fluid 6tream, the 6econd embodiment of the centrifugal separstor and control sy~tem would be used. The second embodiment i6 shown in FI~URE 2. The operation of the io second embodiment i6 6imilar eo that of the first embodiment shown in FIGURE 1, but ha6 an additional inner rotor a66embly 200 and flow pas6ages that remove 6and and other solid6. Fluid flow nozzle 50 introduce6 the fluid 6tream containing the particulates into inner rotor 202 where the fluids begin to be accelerated.
The sand and any other solid6, after contacting the rotor wall of inner rotor 202, are moved to the large radius area of the inner rotor 202 and into the sandlwater 6coop 206 that extends from centerpost 14. The 6and/water 8COOp system, unlike the oil and water removal 6ystem6, i8 a con6tant bleed 6y6tem that is continuou61y remo~ing a 8mall, constant volume stream out of the inner rotor and discharging it out of centrifuge 10 through sand/water pa6~age 208. Sand/water pa66age 208 may u6e a small or~ice 212 to control the ~mount of 6and and water removed from inner rotor 202. Other control6 ~uch a6 adju6table needle valves or po6itive chokes are available to provide a con6tant bleed removal syst~em. A ~mall water 6trea~ may be injected through clean water flow pa66ag~e 210 and feed no~zle 204 into inner rotor 202 to insure that ~and/~ater 8COOp 206 ha6 a continuous wa~er strea~ to it and to maimtain clean water that a66i~t6 in "wa6hing" the 6ma11 oil particles from the produced 6and.

:' . !

It is helpful during the removal of the 6and from the wall of inner rotor 202 to agitate the ~and immediately in front of 6and/water 8COOp 206. FIGURE 5 6hows a view of fluid scoop 206 that incorporates a particulate agitator. Water rotating in inner rotor 202 i~ jetted through nozzle 219 through passage 220 out opening 221 to a point immediately in front of 8COOp passage opening 208. As the water is jetted out opening 221, sand is liftet off the wall of inner rotor 202 and picked up by sand/water 8COOp 206 for discharge through sand/water passage 208.

The fluid stream, now free of any solids that may have been introduced into the centrifuge, exits inner rotor 202 and is accelerated by feed accelerator impeller 52 to full rotor speed where it is separated as described above.

: ~ 15 ~ During the startup of centrifuge lO, it i6 desirable to ; ~ prime the separator with a small volume of the heavier fluid to be separated in order to form a fluid layer for control and seal purposes. Thi6 sealing would prevent the undesirable po~sibility Of oil going out the water discharge line during startup.

A typical sized oil and water centrifugal ~eparator, with a 10,000 barrel~ of fluid per day capacity, would be approximately 6 feet (1.83 meters) in length and 3 feet (0.91 meter) i~ diameter. The volume required to prime a device thi~

size would be approximately 18 gallons of water. A6 rotor 12 rotates, the prime water would be introduced through feed flange -27- 13320~6 46 and through flow passage 48 and fluid feed nozzle 50. The prime water would flow out from feed accelerator impeller 52 to liner 54 and through flow passage 100 and into passage 56. This prine water would therefore prevent any produced oil from flooding flow passsge 56 and reaching oil retention chamber 112 where it would be discharged through water flo~ passage 120 a~
producet water.

The centrifuge separator and level control systém, a~
described herein, provide extremely efficient separation of the components of a well stream. Uowever, a~ previously discussed, several items included in the preferred embodiment6 shown in FIGURE 1 and FIGURE 2 are not required for the operation of centrifuge separator. FIGURE 6 ~hows one of many possible apparatu6 that may be con6tructed in conjunction with these ;~ ~ specifications, but which does not contain every element as `~ prev~ously described in FIGURE 1 or FIGU~E 2.
~::
~- FIGURE 6 6hows the ba6ic components of the centrifugal separator of this invention. Item6 that are not required ~nd are omitted in the embodiment shown in FIGURE 6, include an acceleration impeller, an acceleration bowl, a liner, coalescing mesh, vane6, and a ~im oil 8COOp- Also flow passages 100~ 110, and 56 of FIGURE 1 are replaced by flow pas~age 101. Flow passage 101 i6 formed between the bottom of plate 70, which forms oil retention cham~er 68, and rotor 12.

In the operation of the embodiment shown in FIGURE 6, fluids, introduced into centrifuge 10 through inlet pss6age 48, exit inlet nozzle 50 and move towards rotor 12. Any ga6 present ~ !

moves away from the rotor wall and towards main opening 57 of rotor 12. When enough ga6 enter~ rotor 12, the gas pressiure will increase and be released through pas~iage 138 a6 de6cribed earlier in the preferred embodiment. The fluids, after separating from the gas, move toward~ the rotor where they will contact the rotor or other fluid~ already in the rotor and begin spinning at rotor speed. As the rotating fluids move along the rotor wall, they will ~eparate into their heavier component (water) ant lighter components (oil). The water will form a liquid layer immediately adjacent to the rotor wall and the oil will form a liquid layer ; on top of the water layer. When enough oil enters the centrifuge, it will overflow weir 72 and flow into oil retention chamber 68 and begin filling oil retention chamber 68.

Between the gas and the oil layer is the gas-oil interface 61 on which float 60 floats. When enough oil is produced, the associated level control 6ystem, acting with float 60, sensor 96, and controller 92, will open fluid pass-ge 84 to allow the oil to escape just as is described in the operation of the embodiment shown in FIGURE 1. Between the oil layer and the water layer ~8 formed oil-water interface 63 on which interface float 62 floats- ~hen enough water is produced, interface float 62 will rise and upon reaching the specified height, will transmit to sen60r 132 and controller 128, the need to open flow passage 120 to allow water to escape rotor 12, just as ~8 .~ O
~ described in the operation of the embodiment ~hown in FIGURE 1.

; -` !

It is po~sible that the 8COOp8 and retention chambers may be located at the end opposite from that shown in FIGURE 6 or may be located at each end. One or multiple fluid chambers may be located at both ends of rotor 12. Likewi6e, the float 6ensor6 could be placed at any location along rotor wall 12. ~owever~ it is advantageous to put the float level6 in positions where they will have minimal interference from fluids entering rotor 12.
Thi8 means the float6 would probably be best located near the fluid retention chamber6.

As positioned in FIGURE 6, the removal of the liquids from the fluid retention chambers by scoop 80 and scoop 112 would cause concurrent flow along the wall of rotor 12. If the scoop6 and retention chambers were put at opposite ends of the rotor lone 6coop and one retention chamber at each end), countercurrent flow would be induced by the removal of the liquids from rotor 12. The preferred embodiment as described in FIGURE 1 and FIGURE
: 2 includes several improvements over this basic embodiment that allow for a more complete separation of each fluid component~
however; the basic operation of the centrifu~e unit i6 described in FIGURE 6.

~30- 1332~46 Numerou6 te~t6 have been performed using a centrifuge proces60r shown in FIGURE 1 and de6cribed herein. Te6ts with a 12 inches dia~eter by 30 inches long prototype centrifuge being fed a 502 oil and 50~ water mixture 6howed the following re6ult6:

s Oil Dischar~e Water Di c_arge Rate Stream Stream (In total barrel~ (Water in Oil Stream - (Oil in Water Stream -of fluid per day)in Percent)in Part6 Per Million) 1200 0.05 27 1800 0.10 40 (Typical Sales (Typical Di6posal Specification: <0.50~) Specification: <50 PPM) In the prototype centrifuge, fluid pa66age 56, formed between the inner 6urface of rotor 12 and the outer surface of liner 54, had a thickne66 of approximately 0.4 inch (10.2 millimeters).

The distance of weir 72 from the inner 6urface of liner 54 was about 1.0 inch (25.4 millimeter6). With liner 54 having a thickness of about 0.1 inch (2.5 millimeters), the distance of weir 72 from rotor 12 wa6 about 1.5 inches (38.1 millimeters).

Float 60, mounted in cage 58 on liner 54 for floatation on the oil la~er surface, was capable of 61ight movement on the oil ~urface at a di6tance from the inner surface of rotor 12 approximately equal to the distance between weir 72 and the inner surface of rotor 12 (about 1.5 inches or 3~.1 millimeters). The movement of float 60 in cage 58 wa6 on the order of + 0.1 inch (2.54 millimeters). Similarly, interface float 62, mounted in cage 64, was capable of slight movement on the oil-water interface 6urface about 0.35 inch (8.9 millimeters) from the inner 6urface of liner 54. Movement of float 62 in cage 64 was on the order of + 0.1 inch (2.54 millimeters).

-31- ~33204~

Larger centrifuge separators may have larger clearances in flow passage 56 for greater fluid handling capacities. Al~o, as the centrifuge capacity increases, the height of weir 72 may increase for a larger flow passage 100 and 56. An increase in weir height 72 would also necessitate increasing the distance of float 60 and float 62 from liner 54. Accordingly, these distances and dimensions are in no way intended to be absolute design limitations or operating ranges.

It will be apparent to tho~e skilled in art that various changes may be made în the details of construction of the apparatus and the details of the methods as disclosed herein without departing from the spirit and scope of the invention. Such changes in details are included within the scope of this invention as defined in the following claims.

! ~ ~ i , I

Claims

1. A method for separating the components of a stream comprised of a plurality of fluids having different specific gravities, said method comprising the steps of:
introducing the stream into a rotor having a rotor wall and opposed first and second end portions and a plurality of fluid removal sections attached to the rotor;
rotating the rotor to cause a radial separation of the fluids wherein the fluids are forced outward to the rotor wall forming a plurality of fluid layers so that the fluid layer adjacent to the rotor wall has the greatest relative specific gravity and the successive layers approaching the rotor's rotational axis have successively lower specific gravities so that interfaces form between each separated fluid;
detecting the position of each interface by means of detectors; and removing the individual fluids by flowing each fluid into a fluid removal section and removing each individual fluid from the rotor by opening a fluid scoop passage in response to said detecting of each interface when each fluid layer reaches a specified thickness.

2. The method of claim 1 wherein said method further comprises detecting the position of each interface by determining the location of a plurality of floats floating on the interfaces between the layers, each of the floats having a specific gravity less than the specific gravity of the layer on which it is floating and greater than the specific gravity of the layer on which it is submerged.

3. The method of claim 1 wherein at least one of the fluids is a gas, wherein said method further comprises the step of removing the gas when a specified pressure is reached in the gas layer, thereby maintaining a specified rotor pressure.

4. The method of claim 2 wherein at least one of the fluids is a gas, wherein said method further comprises the step of removing the gas when a specified pressure is reached in the gas layer, whereby maintaining a specified rotor pressure.

5. A method for separating the components of a stream comprised of a plurality of fluids having different specific gravities and particulates, said method comprising the steps of:
introducing the stream into a centrifuge having an inner rotor and a main rotor, the inner rotor being inside the main rotor and having a concaved rotor wall, the main rotor having a rotor wall and opposed first and second end portions and multiple fluid removal sections attached to the rotor;
rotating the inner rotor to create a centrifugal force sufficient to move the particulates against the inner rotor wall;
removing the separated particulates from the inner rotor;
spilling the plurality of fluids out of the inner rotor and into the main rotor;

rotating the main rotor to cause a radial separation of the fluids wherein the fluids are forced outward to the main rotor wall forming a plurality of fluid layers so that the fluid layer adjacent to the rotor wall has the greatest relative specific gravity and successive layers approaching the rotor's rotational axis have successively lower specific gravities;
detecting the position of each interface by means of detectors; and removing the individual fluids by flowing each fluid into a fluid removal section and removing each individual fluid from the rotor by opening a fluid scoop passage in response to said detecting of each interface when each fluid layer reaches a specified thickness.

6. The method of claim 5 wherein said method further comprises detecting the position of each interface by determining the location of a plurality of floats floating on the interfaces between the layers, each of the floats having a specific gravity less than the specific gravity of the layer on which it is floating and greater than the specific gravity of the layer on which it is submerged.

7. The method of claim 5 wherein at least one of the fluids is a gas, wherein said method further comprises the step of removing the gas when a specified pressure is reached in the gas layer, whereby maintaining a specified rotor pressure.

8. The method of claim 6 wherein at least one of the fluids is a gas, wherein said method further comprises the step of removing the gas when a specified pressure is reached in the gas layer, whereby maintaining a specified rotor pressure.

9. A method for centrifugally separating components of a stream which is comprised of a first liquid and a second liquid, said first liquid being heavier than the second liquid, said method comprising the steps of:
continuously introducing said stream into a rotating rotor having a rotor wall and opposed first and second end portions, the first and second liquids rotating in the rotor to form a first liquid layer and a second liquid layer with an interface between the layers;
sensing movement of the interface between the first and second liquid layers by means of a first sensing means;
sensing movement of the inner surface of the second liquid layer by means of a second sensing means:
extracting the first liquid from the rotor in response to said first sensing means to maintain the interface between the first and second liquids within a predetermined distance from the rotor wall; and extracting the second liquid from the rotor in response to the second sensing means to maintain the level of the inner surface of the second liquid within a predetermined range.

10. An apparatus for separating the components of a stream comprised of a plurality of fluids having different specific gravities, said apparatus comprised of:
a rotor adapted for rotation about an axis, the rotor having a rotor wall and opposed first and second end portions defining an opening inside the rotor;
a fluid feed flow passage mounted in the opening in the rotor to introduce the stream into the rotor;
a heavy fluid chamber attached to the rotor;
a heavy fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the rotor and into the heavy fluid chamber for removing heavy fluids from the chamber;
a light fluid chamber attached to the rotor;
a light fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the rotor and into the light fluid chamber for removing light fluids from the chamber;
a means for detecting the radial location of a first and a second fluid interface and producing a signal relative thereto;
a means for regulating flow through the heavy liquid scoop in response to said detecting means in locating the radial position of the first fluid interface; and a means for regulating flow through the light fluid scoop in response to said detecting means in locating the radial position of the second fluid interface.

11. An apparatus for separating the components of a stream comprised of a plurality of fluids having different specific gravities, said apparatus comprised of:
a rotor adapted for rotation about an axis, the rotor having a rotor wall and opposed first and second end portions defining an opening inside the rotor;
a fluid feed flow passage mounted in the opening in the rotor to introduce the stream into the rotor;
a heavy fluid chamber attached to the rotor;
a heavy fluid scoop mounted in the opening in the rotor ant having a flow passage extending outward from the rotational axis of the rotor and into the heavy fluid chamber for removing heavy fluids from the chamber;
a light fluid chamber attached to the rotor;
a light fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the rotor and into the light fluid chamber for removing light fluids from the chamber;
a weir connected to the rotor adjacent to the light fluid chamber and extending radially inwardly from the rotor wall a distance sufficient to permit light fluids to overflow the weir and enter the light fluid chamber;
a first detector for radially locating a first fluid layer interface and producing a signal relative thereto;
a second detector for radially locating a second fluid layer interface and producing a signal relative thereto;
a first signal converter in communication with the first detector capable of receiving the signal produced by the first detector and producing a varying output signal to a means for regulating flow through the heavy fluid scoop;

a second signal converter in communication with the second detector capable of receiving the signal produced by the second detector and producing a varying output signal to a means for regulating flow through the light fluid scoop;
a means for regulating flow through the heavy fluid scoop in response to the varying output signal from the first signal converter, whereby maintaining a specified heavy fluid level; and a means for regulating flow through the light fluid scoop in response to the varying output signal from the second signal converter, whereby maintaining a specified light fluid level.

12. An apparatus for separating the components of a stream comprised of a plurality of fluids having different specific gravities, said apparatus comprised of:
a rotor adapted for rotation about an axis, the rotor having a rotor wall and opposed first and second end portions defining an opening inside the rotor;
a fluid feed flow passage mounted in the opening in the rotor to introduce the stream into the rotor;
a heavy fluid chamber attached to the main rotor;
a heavy fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the rotor and into the heavy fluid chamber for removing heavy fluids from the chamber;
a light fluid chamber attached to the rotor;

a light fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the rotor and into the light fluid chamber for removing light fluids from the chamber;
a weir connected to the rotor adjacent to the light fluid chamber and extending radially inwardly from the rotor wall a distance sufficient to permit light fluids to overflow the weir and enter the light fluid chamber;
a first float in the opening in the rotor floating on a first fluid interface and adapted for radial movement with respect to the rotational axis of the rotor;
a second float in the opening in the rotor floating on a second fluid interface and adapted for radial movement with respect to the rotational axis of the rotor;
a first detector for radially locating the first float and producing a signal relative thereto;
a second detector for radially locating the second float and producing a signal relative thereto;
a first signal converter in communication with the first detector capable of receiving the signal produced by the first detector and producing a varying output signal to a means for regulating flow through the heavy fluid scoop;
a second signal converter in communication with the second detector capable of receiving the signal produced by the second detector and producing a varying output signal to a means for regulating flow through the light fluid scoop;

a means for regulating flow through the heavy fluid scoop in response to the varying output signal from the first signal converter, whereby maintaining a specified heavy fluid level; and a means for regulating flow through the light fluid scoop in response to the varying output signal from the second signal converter, whereby maintaining a specified light fluid level.

13. The apparatus of claim 11 further adapted to additionally handle gas, and further comprising:
a third fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the rotor for removing gas from the rotor; and a pressure regulating device communicating with the third flow passage, whereby a specified rotor pressure is maintained.

14. The apparatus of claim 12 further adapted to additionally handle gas, and further comprising:
a third fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the rotor for removing gas from the rotor; and a pressure regulating device communicating with the third flow passage, whereby a specified rotor pressure is maintained.

15. The apparatus of claim 11 and further comprising:
a fluid acceleration impeller adapted for rotation with the rotor and capable of receiving fluid from the fluid feed flow passage; and a coalescing material adapted for rotation with the rotor.

16. The apparatus of claim 12 and further comprising:
a fluid acceleration impeller adapted for rotation with the rotor and capable of receiving fluid from the fluid feed flow passage; and a coalescing material adapted for rotation with the rotor.

17. The apparatus of claim 13 and further comprising:
a fluid acceleration impeller adapted for rotation with the rotor and capable of receiving fluid from the fluid feet flow passage; and a coalescing material adapted for rotation with the rotor.

18. The apparatus of claim 14 and further comprising:
a fluid acceleration impeller adapted for rotation with the rotor and capable of receiving fluid from the fluid feed flow passage; and a coalescing material adapted for rotation with the rotor.

19. An apparatus for separating the components of a stream comprised of a plurality of fluids having different specific gravities and particulates, said apparatus comprised of:
a main rotor adapted for rotation about an axis, the main rotor having a rotor wall and opposed first and second end portions defining an opening inside the rotor;
an inner rotor mounted inside of the main rotor adapted for rotation with the main rotor, said inner rotor having an inner rotor wall defining an opening incite the inner rotor and being adapted to receive flow from a fluid feed flow passage;
a sand/water scoop mounted in the opening in the inner rotor and having a flow passage extending outward from the rotational axis of the main rotor and inner rotor to the wall of the inner rotor for removing sand from the inner rotor;
a sand/water outlet orifice communicating with the flow passage of the sand/water scoop;
a water makeup line mounted in the opening in the inner rotor and having a flow passage extending outward from the rotational axis of the main rotor and inner rotor into said inner rotor;
a water inlet orifice communicating with the flow passage of the water makeup line;
a fluid feed flow passage mounted in the opening in the inner rotor to introduce the stream into the inner rotor;
a heavy fluid chamber attached to the main rotor;

a heavy fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the main rotor and into the heavy fluid chamber for removing heavy fluids from the chamber;
a light fluid chamber attached to the rotor;
a light fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the main rotor and into the light fluid chamber for removing light fluids from the chamber;
a weir connected to the main rotor adjacent to the light fluid chamber and extending radially inwardly from the rotor wall a distance sufficient to permit light fluids to overflow the weir and enter the light fluid chamber;
a first detector for radially locating a first fluid layer interface and producing a signal relative thereto;
a second detector for radially locating a second fluid layer interface and producing a signal relative thereto;
a first signal converter in communication with the first detector capable of receiving the signal produced by the first detector and producing a varying output signal to a means for regulating flow through the heavy fluid scoop;
a second signal converter in communication with the second detector capable of receiving the signal produced by the second detector and producing a varying output signal to a means for regulating flow through the light fluid scoop;

a means for regulating flow through the heavy fluid scoop in response to the varying output signal from the first signal converter, whereby maintaining a specified heavy fluid level; and a means for regulating flow through the light fluid scoop in response to the varying output signal from the second signal converter, whereby maintaining a specified light fluid level.

20. An apparatus for separating the components of a stream comprised of a plurality of fluids having different specific gravities and particulates, said apparatus comprised of:
a main rotor adapted for rotation about an axis, the main rotor having a rotor wall and opposed first and second end portions defining an opening inside the main rotor;
an inner rotor mounted inside of the main rotor adapted for rotation with the main rotor, said inner rotor having an inner rotor wall defining an opening inside the inner rotor and being adapted to receive flow from a fluid feed flow passage;
a sand/water scoop mounted in the opening in the inner rotor and having a flow passage extending outward from the rotational axis of the main rotor and inner rotor to the wall of the inner rotor for removing sand from the inner rotor;
a sand/water outlet orifice communications with the flow passage of the sand/water scoop;

a water makeup line mounted in the opening in the inner rotor and having a flow passage extending outward from the rotational axis of the main rotor and inner rotor into said inner rotor;
a water inlet orifice communicating with the flow passage of the water makeup line;
a fluid feed flow passage mounted in the opening in the inner rotor to introduce the stream into the inner rotor;
a heavy fluid chamber attached to the main rotor;
a heavy fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the main rotor and into the heavy fluid chamber for removing heavy fluids from the chamber;
a light fluid chamber attached to the rotor;
a light fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the main rotor ant into the light fluid chamber for removing light fluids from the chamber;
a weir connected to the main rotor adjacent to the light fluid chamber and extending radially inwardly from the rotor wall a distance sufficient to permit light fluids to overflow the weir and enter the light fluid chamber;
a first float in the opening in the main rotor floating on a first fluid interface and adapted for radial movement with respect to the rotational axis of the rotor;
a second float in the opening in the main rotor floating on a second fluid interface and adapted for radial movement with respect to the rotational axis of the rotor;

a first detector for radially locating the first float and producing a signal relative thereto;
a second detector for radially locating the second float and producing a signal relative thereto;
a first signal converter in communication with the first detector capable of receiving the signal produced by the first detector and producing a varying output signal to a means for regulating flow through the heavy fluid scoop;
a second signal converter in communication with the second detector capable of receiving the signal produced by the second detector and producing a varying output signal to a means for regulating flow through the light fluid scoop;
a means for regulating flow through the heavy fluid scoop in response to the varying output signal from the first signal converter, whereby maintaining a specified heavy fluid level; and a means for regulating flow through the light fluid scoop in response to the varying output signal from the second signal converter, whereby maintaining a specified light fluid level.

21. The apparatus of claim 19 further adapted to additionally handle gas, and further comprising:
a third fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the main rotor for removing gas from the rotor; and a pressure regulating device communicating with the third flow passage, whereby a specified rotor pressure is maintained.

22. The apparatus of claim 20 further adapted to additionally handle gas, and further comprising:
a third fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the main rotor for removing gas from the rotor; and a pressure regulating device communicating with the third flow passage, whereby a specified rotor pressure is maintained.

23. The apparatus of claim 19 and further comprising:
a fluid acceleration impeller adapted for rotation with the rotor and capable of receiving fluid from the fluid feed flow passage; and a coalescing material adapted for rotation with the rotor.

24. The apparatus of claim 20 and further comprising:
a fluid acceleration impeller adapted for rotation with the rotor and capable of receiving fluid from the fluid feed flow passage; and a coalescing material adapted for rotation with the rotor.

25. The apparatus of claim 21 and further comprising:
a fluid acceleration impeller adapted for rotation with the rotor and capable of receiving fluid from the fluid feed flow passage; and a coalescing material adapted for rotation with the rotor.

26. The apparatus of claim 22 ant further comprising:
a fluid acceleration impeller adapted for rotation with the rotor and capable of receiving fluid from the fluid feed flow passage; and a coalescing material adapted for rotation with the rotor.

27. An apparatus for separating the components of a stream comprised of a plurality of fluids having different specific gravities, said apparatus comprised of:
a rotor adapted for rotation about an axis, the rotor having a rotor wall, and opposed first and second end portions defining an opening inside the rotor;
a fluid feed flow passage mounted in the opening in the rotor to introduce the stream into the rotor;
a liner attached to the rotor creating a flow passage between the liner and the rotor along the rotor;
a heavy fluid chamber attached to the rotor;
a heavy fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the rotor and into the heavy fluid chamber for removing heavy fluids from the chamber;
a light fluid chamber attached to the rotor;
a light fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the rotor ant into the light fluid chamber for removing light fluid from the chamber;

a weir connected to the rotor adjacent to the light fluid chamber and extending radially inwardly from the rotor wall a distance sufficient to permit light fluids to overflow the weir and enter the light fluid chamber;
a skim oil fluid chamber attached to the rotor;
a skim oil fluid removal scoop mounted in the opening in the rotor and having a flow passage extending outward from the fluid feed flow passage and into the skim oil fluid chamber, whereby removing skim oil from the chamber for reseparating in the rotor;
a first detector for radially locating a first fluid layer interface and producing a signal relative thereto;
a second detector for radially locating a second fluid layer interface and producing a signal relative thereto;
a first signal converter in communication with the first detector capable of receiving the signal produced by the first detector and producing a varying output signal to a means for regulating flow through the heavy fluid scoop;
a second signal converter in communication with the second detector capable of receiving the signal produced by the second detector and producing a varying output signal to a means for regulating flow through the light fluid scoop;
a means for regulating flow through the heavy fluid scoop in response to the varying output signal from the first signal converter, whereby maintaining a specified heavy fluid level; and a means for regulating flow through the light fluid scoop in response to the varying output signal from the second signal converter, whereby maintaining a specified light fluid level.

28. An apparatus for separating the components of a stream comprised of a plurality of fluids having different specific gravities, said apparatus comprised of:
a rotor adapted for rotation about an axis, the rotor having a rotor wall and opposed first and second end portions defining an opening inside the rotor;
a fluid feed flow passage mounted in the opening in the rotor to introduce the stream into the rotor;
a liner attached to the rotor creating a flow passage between the liner and the rotor along the rotor;
a heavy fluid chamber attached to the rotor;
a heavy fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the rotor and into the heavy fluid chamber for removing heavy fluids from the chamber;
a light fluid chamber attached to the rotor;
a light fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the rotor and into the light fluid chamber for removing light fluids from the chamber;
a weir connected to the rotor adjacent to the light fluid chamber ant extending radially inwardly from the rotor wall a distance sufficient to permit light fluids to overflow the weir and enter the light fluid chamber;
a skim oil fluid chamber attached to the rotor;

a skim oil fluid removal scoop mounted in the opening in the rotor and having a flow passage extending outward from the fluid feed flow passage and into the skim oil fluid chamber, whereby removing skim oil from the chamber for reseparation in the rotor;
a first float in the opening in the main rotor floating on a first fluid interface and adapted for radial movement with respect to the rotational axis of the rotor;
a float in the opening in the main rotor floating on a second fluid interface and adapted for radial movement with respect to the rotational axis of the rotor;
a first detector for radially locating the first float and producing a signal relative thereto;
a second detector for radially locating the second float and producing a signal relative thereto;
a first signal converter in communication with the first detector capable of receiving the signal produced by the first detector and producing a varying output signal to a means for regulating flow through the heavy fluid scoop;
a second signal converter in communication with the second detector capable of receiving the signal produced by the second detector and producing a varying output signal to a means for regulating flow through the light fluid scoop;
a means for regulating flow through the heavy fluid scoop in response to the varying output signal from the first signal converter, whereby maintaining a specified heavy fluid level; and a means for regulating flow through the light fluid scoop in response to the varying output signal from the second signal converter, whereby maintaining a specified light fluid level.

29. The apparatus of claim 27 and further comprising:
a third fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the main rotor for removing gas from the rotor; and a pressure regulating device communicating with the third flow passage, whereby a specified rotor pressure is maintained.

30. The apparatus of claim 28 and further comprising:
a third fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the main rotor for removing gas from the rotor; and a pressure regulating device communicating with the third flow passage, whereby a specified rotor pressure is maintained.

31. The apparatus of claim 27 and further comprising:
a fluid acceleration impeller adapted for rotation with the rotor and capable of receiving fluid from the fluid feed flow passage;
a first coalescing material in the flow passage between the liner and the rotor; and a second coalescing material on the inner surface of the liner.

32. The apparatus of claim 28 and further comprising:
a fluid acceleration impeller adapted for rotation with the rotor and capable of receiving fluid from the fluid feed flow passage;
a first coalescing material in the flow passage between the liner and the rotor; and a second coalescing material on the inner surface of the liner.

33. The apparatus of claim 29 and further comprising:
a fluid acceleration impeller adapted for rotation with the rotor and capable of receiving fluid from the fluid feed flow passage;
a first coalescing material in the flow passage between the liner and the rotor; and a second coalescing material on the inner surface of the liner.

34. The apparatus of claim 30 and further comprising:
a fluid acceleration impeller adapted for rotation with the rotor and capable of receiving fluid from the fluid feed flow passage;
a first coalescing material in the flow passage between the liner and the rotor; and a second coalescing material on the inner surface of the liner.

35. An apparatus for separating the components of a stream comprised of a plurality of fluids having different specific gravities and particulates, said apparatus comprised of:
a main rotor adapted for rotation about an axis, the main rotor having a rotor wall and opposed first and second end portions defining an opening inside the rotor;
an inner rotor mounted inside of the main rotor adapted for rotation with the main rotor, said inner rotor having an inner rotor wall defining an opening inside the inner rotor and being adapted to receive flow from a fluid feed flow passage;
a sand/water scoop mounted in the opening in the inner rotor and having a flow passage extending outward from the rotational axis of the main rotor and inner rotor to the wall of the inner rotor for removing sand from the inner rotor;
a sand/water outlet orifice communications with the flow passage of the sand/water scoop;
a water makeup line mounted in the opening in the inner rotor and having a flow passage extending outward from the rotational axis of the main rotor and inner rotor into said inner rotor;
a water inlet orifice communicating with the flow passage of the water makeup line;
a fluid feed flow passage mounted in the opening in the inner rotor to introduce the stream into the inner rotor;

a liner attached to the main rotor creating a flow passage between the liner and the main rotor along the main rotor;
a heavy fluid chamber attached to the main rotor;
a heavy fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the main rotor and into the heavy fluid chamber for removing heavy fluids from the chamber;
a light fluid chamber attached to the main rotor;
a light fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the main rotor and into the light fluid chamber for removing light fluids from the chamber;
a weir connected to the main rotor adjacent to the light fluid chamber and extending radially inwardly from the rotor wall a pre-selected distance sufficient to permit light fluids to overflow the weir and enter the light fluid chamber;
a skim oil fluid chamber attached to the main rotor;
a skim oil fluid removal scoop mounted in the opening in the rotor and having a flow passage extending outward from the fluid feed flow passage and into the skim oil fluid chamber, whereby removing skim oil from the chamber for reseparation in the main rotor;
a first detector for radially locating a first fluid layer interface and producing a signal relative thereto;
a second detector for radially locating a second fluid layer interface and producing a signal relative thereto;

a first signal converter in communication with the first detector capable of receiving the signal produced by the first detector and producing a varying output signal to a means for regulating flow through the heavy fluid scoop;
a second signal converter in communication with the second detector capable of receiving the signal produced by the second detector and producing a varying output signal to a means for regulating flow through the light fluid scoop;
a means for regulating flow through the heavy fluid scoop in response to the varying output signal from the first signal converter, whereby maintaining a specified heavy fluid level; and a means for regulating flow through the light fluid scoop in response to the varying output signal from the second signal converter, whereby maintaining a specified light fluid level.

36. An apparatus for separating the components of a stream comprised of a plurality of fluids having different specific gravities and particulates, said apparatus comprised of:
a main rotor adapted for rotation about an axis, the main rotor having a rotor wall and opposed to first and second end portions defining an opening inside the rotor;
an inner rotor mounted inside of the main rotor adapted for rotation with the main rotor, said inner rotor having an inner rotor wall defining an opening inside the inner rotor and being adapted to receive flow from a fluid feed flow passage;

a sand/water scoop mounted in the opening in the inner rotor and having a flow passage extending outward from the rotational axis of the main rotor and inner rotor to the wall of the inner rotor for removing sand from the inner rotor;
a sand/water outlet orifice communications with the flow passage of the sand/water scoop;
a water makeup line mounted in the opening in the inner rotor and having a flow passage extending outward from the rotational axis of the main rotor and inner rotor into said inner rotor;
a water inlet orifice communicating with the flow passage of the water makeup line;
a fluid feed flow passage mounted in the opening in the inner rotor to introduce the stream into the inner rotor;
a liner attached to the main rotor creating a flow passage between the liner and the main rotor along the main rotor;
a heavy fluid chamber attached to the main rotor;
a heavy fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the main rotor and into the heavy fluid chamber for removing heavy fluids from the chamber;
a light fluid chamber attached to the main rotor;
a light fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the main rotor and into the light fluid chamber for removing light fluids from the chamber;

a weir connected to the main rotor adjacent to the light fluid chamber and extending radially inwardly from the rotor wall a distance sufficient to permit light fluids to overflow the weir and enter the light fluid chamber;
a skim oil fluid chamber attached to the main rotor;
a skim oil fluid removal scoop mounted in the opening in the rotor and having a flow passage extending outward from the fluid feed flow passage and into the skim oil fluid chamber, whereby for removing skim oil from the chamber for reseparation in the main rotor;
a first float in the opening in the main rotor floating on a first fluid interface and adapted for radial movement with respect to the rotational axis of the rotor;
a second float in the opening in the main rotor floating on a second fluid interface and adapted for radial movement with respect to the rotational axis of the rotor;
a first detector for radially locating the first float and producing a signal relative thereto;
a second detector for radially locating the second float and producing a signal relative thereto;
a first signal converter in communication with the first detector capable of receiving the signal produced by the first detector and producing a varying output signal to a means for regulating flow through the heavy fluid scoop;
a second signal converter in communication with the second detector capable of receiving the signal produced by the second detector and producing a varying output signal to a means for regulating flow through the light fluid scoop;

a means for regulating flow through the heavy fluid scoop in response to the varying output signal from the first signal converter, whereby maintaining a specified heavy fluid level; and a means for regulating flow through the light fluid scoop in response to the varying output signal from the second signal converter, whereby maintaining a specified light fluid level.

37. The apparatus of claim 35 and further comprising:
a third fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the main rotor for removing gas from the rotor; and a pressure regulating device communicating with the third flow passage, whereby a specified rotor pressure is maintained.

38. The apparatus of claim 36 and further comprising:
a third fluid scoop mounted in the opening in the rotor and having a flow passage extending outward from the rotational axis of the main rotor for removing gas from the rotor; and a pressure regulating device communicating with the third flow passage, whereby a specified rotor pressure is maintained.

39. The apparatus of claim 35 and further comprising:
a fluid acceleration impeller adapted for rotation with the rotor and capable of receiving fluid from the fluid feed flow passage;
a first coalescing material in the flow passage between the liner and the rotor; and a second coalescing material on the inner surface of the liner.

40. The apparatus of claim 36 and further comprising:
a fluid acceleration impeller adapted for rotation with the rotor and capable of receiving fluid from the fluid feed flow passage;
a first coalescing material in the flow passage between the liner and the rotor; and a second coalescing material on the inner surface of the liner.

41. The apparatus of claim 37 and further comprising:
a fluid acceleration impeller adapted for rotation with the rotor and capable of receiving fluid from the fluid feed flow passage;
a first coalescing material in the flow passage between the liner and the rotor; and a second coalescing material on the inner surface of the liner.

42. The apparatus of claim 38 and further comprising:
a fluid acceleration impeller adapted for rotation with the rotor and capable of receiving fluid from the fluid feed flow passage;
a first coalescing material in the flow passage between the liner and the rotor; and a second coalescing material on the inner surface of the liner.