CA2252306A1 - Liquid separator - Google Patents
Liquid separator Download PDFInfo
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- CA2252306A1 CA2252306A1 CA002252306A CA2252306A CA2252306A1 CA 2252306 A1 CA2252306 A1 CA 2252306A1 CA 002252306 A CA002252306 A CA 002252306A CA 2252306 A CA2252306 A CA 2252306A CA 2252306 A1 CA2252306 A1 CA 2252306A1
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- separation
- water
- ceramic
- hydrocyclone
- liquids
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
- B01D17/02—Separation of non-miscible liquids
- B01D17/0217—Separation of non-miscible liquids by centrifugal force
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D21/00—Separation of suspended solid particles from liquids by sedimentation
- B01D21/26—Separation of sediment aided by centrifugal force or centripetal force
- B01D21/267—Separation of sediment aided by centrifugal force or centripetal force by using a cyclone
Abstract
The liquid separator is a molded or cast ceramic separation apparatus which causes centrifugal and centripetal-forces to be imparted on an incoming fluid stream which could be made up of two differing liquids such as oil and water or a fluid containing a solids/liquid mixture. The apparatus may be designed with modifications to be used in solids/liquids separations involving suspended solids such as sediments and bacteria-like organisms for separation from source water for use in ships' ballast water or similar types of separation applications. It can also be designed for the separation of two differing liquid phases such as oil and water. The separator may be used to remove large amounts of higher density water from an incoming process stream or it can be used for water cleanup applications. As well, it can be used where there are two liquids of varying density which require a separation of the two liquids involved.
Description
TEM File no. 202.1 .TITLEi LIQUID SEPARATOR
FIELD OF THE INVENTION
The present invention relates to a molded or cast ceramic separation apparatus which causes centrifugal and centripetal forces to be imparted on an incoming fluid stream which could be made up of two differing liquids such as oil and water or a fluid containing a solids/liquid mixture.
to The apparatus may be designed with modifications to be used in solidslliquids separations involving suspended solids such as sediments and bacteria-like organisms for separation from source water for use in ships' ballast water or similar types of separation applications. It can also be designed for the separation of two differing liquid phases such as oil and water.
The invention is designed to be used to remove large amounts of higher density water from an incoming process stream or it can be used for water cleanup applications.
As well, it can be used where there are two liquids of varying density which require a separation of the two liquids involved.
2o BACKGROUND OF THE INVENTION
There are two areas of interest and potential application of the invention.
The first is the separation of oil and water in oilfield production operations and the second is the separation of solids from a sourcewater for ships ballast water to reduce the presence of solids and/or the transit and exchange of Aquatic Nuisance Species.
Produced Water Application of the Invention Presently in oilfield operations it is necessary to handle large volumes of produced water to recover hydrocarbons. Horizontally drilled wells, aging pools and reservoirs which utilize water flooding techniques often become affected areas. The basic result of these factors produces crude oil emulsion streams which contain increasingly higher water/oil ratios as opposed to initial oil production that typically yield lower water/oil ratios.
There is a requirement in oilfield operations for an apparatus and/or process for the separation of a highly water laden fluid, but which does not rely entirely upon gravity 1o settling as its main vehicle for the separation of the two liquids involved. A separation device which accelerates the separation of the two liquids and addresses environmental concerns, increases the producing life of a reservoir while ef~lciently handling large volumes of produced water prior to disposal and/or reinjection, is particularly desirable.
It must be stated, however, that the present invention will not solely be directed toward oilfield types of operations but also in any application where there is a requirement to separate two substances of varying density, or what is referred to either as a "liquid/liquid" separation or a "solids/liquid" separation. The technology that is presented utilizes accepted scientific principles of physics in the separation of fluids.
The current method of gravity separation uses Stokes Law, which states that "through time an emulsion fluid of oil and water will separate with the effect of gravity"
and is based on mass (droplet size) and the proportional density difference between oil and water which governs the falling or settling velocity. Basically, the lighter phase fluids will rise to the top and the heavier or denser phase fluids will fall to the bottom. Residence time and/or general gravity settling volume is important to these types of systems, and therefore heat and chemicals are added to accelerate emulsion separation in conventional gravity settling systems. The proposed invention differs from conventional gravity settling systems because it uses centripetal and centrifugal forces to cause separation of the two liquids as opposed to gravity settling principles as outlined in Stokes' Law.
The principles of liquid/liquid separation using centrifugal and centripetal forces are relatively new and it can be stated that each liquid/liquid separation requires specific attention in its design. Centrifi.~gal or cyclonic separations normally take one to two seconds to perform and can usually be accomplished with reduced heat or thermal assistance or in many cases a significant reduction in treating and demulsifying chemicals.
1o Similar technology has been used successfully in other areas of the petroleum industry, primarily on off shore water cleanup (deoiling) applications.
Other hydrocyclone inventions use similar accepted cyclonic principles, but the proposed invention is unique in many respects from the existing hydrocyclone technology. The proposed invention can successfi~lly operate at low or high operating differential pressures, and thus the need for other supporting equipment such as pumps is reduced. The existing operating pressures at mainland or offshore production facilities is well within the operating parameters of this invention.
Ballast Water Application of the Invention 2o Ships use ballast water worldwide to operate safely and successfixlly.
Among other uses, ballast aids propulsion and maneuverability by providing weight to submerge the rudder and reduce the amount of exposed hull surface. It also provides for greater stability and reduces stresses on the hull. Water began to be the predominant form of ballast from around the 1880s onward, replacing rocks, sand and other heavy, solid materials.
When a ship takes on ballast, normally in coastal waters outside a port to make up for weight lost after unloading cargo, it also takes on the available solids fraction of the source water (which typically contains sediments, minerals and other suspended solids) along with thousands of microscopic organisms, including plankton species, the planktonic life stages of other marine species, and pathogens. These solids and organisms are then transported in the ship's ballast tank and released when the ballast is discharged when the ship arrives at another port of call.
to The favored method for reducing the risk of introducing alien species into aquatic environments is changing ballast far out at sea. In this technique, ballast water loaded in port or taken on board while transiting inshore waters is changed with Open Ocean water during passage between ports of call. This method is usually effective because most freshwater, estuarine and inshore coastal organisms cannot survive when discharged into the ocean environment. However, exchanging ballast at sea is not always a practical solution because one of the main functions of ballast is to insure the stability of ships at sea, and so exchanging ballast while in transit may threaten the vessel's safety. Hence, it would be desireable to devise ways to eliminate organisms from ballast water as it is taken on board or discharged.
2o Further, because of the presence of the solids in source water, solids will collect in the ballast tanks over time and substantially reduce a ships' cargo carrying capacity.
Because of the large amount of ballast water required by ships, and the relatively high density of the solids fraction constituents as compared to the source water, it does not take a high concentration of solids to equate to as much as 20 to 50 tons of lost cargo carrying capacity per voyage. Source water containing a total suspended solids (TSS) fraction as low as 0.02% can yield a total solids intake of approximately 27 to 30 tons for an average sized cargo ship. Because of the diversity of ocean going vessels, the reduction of solids and the subsequent preservation of approximately 30 tons of cargo carrying capability warrants concern. Solids buildup in ballast water tanks costs ship owners and operators millions of dollars annually in maintenance costs and lost cargo.
Prior Separators The performance of all mechanical gravity settling separators is affected by the 1o same physical parameters. Gravity separators (i.e. skimmers, gas flotation cells and coalescing vessels) can be understood through Stokes Law, which governs the velocity at which a droplet will travel through a continuous phase fluid. This velocity is directly proportional to the density difference between the two liquid phases. The force of gravity usually dictates the size of the droplet's movement. The velocity is inversely proportional to the relative viscosity of the droplet in the continuous phase.
Stokes Law Vt= 1,488 g DPZ (P, - Pi) 18 p.
2o where:
~ Vt =Terminal Settling Velocity (ft/sec.) ~ g - local acceleration due to gravity (32.2 ft/sec.2 ) ~ Dp = Droplet or particle diameter (ft.) ~ p, = liquid phase density continuous phase (Ib/ft3 ~ p2= liquid phase density droplet or particle (Ib/ft3) . P, = viscosity of continuous phase (cp) Separators, which utilize gravity settling, residence time and Stokes Law principles in their design fail to meet the size and weight constraints for a ballast water process application. Filtration vessels also use many of the same separation principles identified in Stokes Law and further involve the exposure of the fluids to a minimum surface area, which adversely affects equipment size and weight. Hence, since ballast water separation applications are subject to the space constraints of ocean going vessels, gravity based settling equipment is virtually eliminated from such application.
Other laws that involve the same variables as Stokes Law describe separators that use centrifugal force such as hydrocyclones, rather than gravity. In a typical liquid/liquid to separation, the conventional reverse flow hydrocyclone escapes Stokes Law in two ways.
First, the mixture is caused to spin inside the unit generating a centrifugal force to drive a less dense droplet through a continuous fluid (denser) phase. This is done simply with pressure, and requires no moving parts. Second, the hydrocyclone has a small diameter resulting in a very short distance in which the less dense droplet must travel in order to be separated from the denser phase. The end result is that the system has a residence time of less than two seconds, compared to the range of six to sixty minutes usually required for gravity based separation systems. This means that it need not be of a large size.
As the fluids pass though the hydrocyclone, the equipment's internal features cause the fluid to spin. High centripetal forces cause the denser phase to be sent outwards while 2o the lighter less dense phase is displaced to the center of the tube body and resulting internal vortex. In reverse flow designs, the stream typically flows through an internal liner. The geometry maintains the vortex and permits the water stream to flow out into a pressure vessel housing, while causing the central core to flow in the reverse direction.
The high centripetal forces required to perform liquid/liquid separation in the short time that the fluid remains within the equipment are produced at the expense of system pressure.
Drawbacks to Existing Hydrocyclone Technology s The reverse flow type of hydrocyclone is not entirely free of compromises.
It does require sufficient dii~erential pressure to operate, typically SOpsig. to 80psig. It is claimed that the more pressure which is available, the more cost effective this type of system becomes due to increased throughput. However, by increasing the available pressure, one must take into account the additional capital and equipment costs especially in ballast 1o water applications involving 3,000 m3/hr to 5,000 m3/hr. flow capacities.
From conventional design theory, it can be surmised that reverse flow hydrocyclone design relies heavily upon the generation of velocity causing the necessary centrifugal forces to be imparted upon the particles to be separated. This design accomplishes this through its geometric configuration. Typically cone shaped, the reverse ~s flow hydrocyclone requires that one of the separated phases be directed backward or in a reverse flow to the inlet flow. By doing so, there is a separate force acting in reverse to the inlet velocities and forces, causing a necessity to generate velocities above these reverse flows which increases the pressure requirements causing a potential inefficiency in the separation.
2o Reverse flow technology requires the creation of a central vortex core (as do all hydrocyclones), but by reversing the flow of this phase there is minimal area and volume in which the separated phase has to commingle, flocculate and discharge from the hydrocyclone body. This design characteristic is a function of the design geometry of the reverse flow hydrocyclone and is why this design of hydrocyclone is so dependent upon the generation of velocity to accomplish its separation.
Hydrocyclone manufacturers claim generally that the centrifugal forces imparted on solids particles are in the order of 10,000 g's. During our research phase, we discovered that there was the possibility that centrifugal forces in this range were responsible for the shearing of oil droplets and that the reverse flow hydrocyclone design may be causing some stabilization to crude oil emulsions as a result. Ballast water applications, for example, involve the separation of solids particles which may be able to withstand centrifugal forces of this magnitude but there is a possibility that imparting an 1o excess of force upon small solids particles would result in further shearing these particles and causing them to be non-recoverable.
There have been many instances where reverse flow hydrocyclone designs have been unsuccessful. The standard solution to increasing separation efficiency was to increase velocity and subsequently increasing centrifugal forces. In most of these instances there was neither an increased efficiency nor a change in performance. This brings forth the question of velocities and whether it is necessary to impart large centrifugal forces in separations involving solids particles in the range of 5 microns to 100 microns.
Further studies into the types of solids particles involved in ballast water 2o separations reveal the solids fraction in source water contains mineral and ash constituents. In some cases, the 0 - 50 micron particles represent up to 25%
of the solids fraction. If the separation efficiency of a reverse flow hydrocyclone is approximately 50%
at this size range there is a significant amount of solids being left in the discharge stream and being sent to the ballast water tanks.
_g_ This brings to light an uncertainty of whether the reverse flow hydrocyclone design or configuration is capable of being combined successfully into an existing ballast water-treating scenario. Most ships do not have pumping equipment that can provide sufficient pressure to drive this type of hydrocyclone design while maintaining acceptable ballast water intake rates. Subsequently, the use of existing ballast water pumps would result in operating at an elevated pressure, which would reduce the pumping capacity and extend ballast water cycles. The alternative to the use of existing equipment is to re-equip all ocean-going vessels with new pumping equipment.
It is not practical to place a reverse flow hydrocyclone in a ballast water system.
1o While this is a possible form of satisfying ballast water separations, it has the potential to unnecessarily add to the complexity, size, weight, operating and maintenance requirements of a ballast water separation system.
What is desired therefore is a ceramic cast or molded hydrocyclone apparatus which overcomes the limitations and disadvantages of other prior art hydrocyclones.
Preferably the hydrocyclone apparatus should be cast or molded from a material such as ceramic, fiberglass or an industrial grade plastic which is capable of providing pressure containment, seamless internal construction and smooth flow properties of process fluids) 2o throughout its entire length.
The present invention has shown in field and laboratory test trials the ability to efficiently and effectively separate two phase liquids at reduced operating and differential pressures when compared to prior art hydrocyclone technology.
If required, the preferred embodiment is capable of being installed as a separate apparatus or in a multiple arrangement which could increase capacity in certain applications.
The invention is designed to be manufactured in a wide range of diameters and lengths to satisfy capacity and varying application requirements. In so doing, the invention would substantially reduce equipment costs and reduce equipment size and weight limitations.
Advantages l0 Existing hydrocyclone designs rely on pressure vessel containment to operate in the applications for which they are designed. The present invention uses a ceramic molded apparatus which is able to withstand the necessary operating pressures and therefore eliminate the need for a pressure vessel entirely.
Other advantages of the proposed invention when compared to conventional gravity settling equipment includes but is not limited to the following:
Minimal residence time, resulting in significant weight and volume reduction;
High efficiency when compared with conventional settling tanks or pressure vessels;
Large flexibility in flow rate and inlet oil concentration;
Easily adaptable to changing field operating conditions; and, 2o Reduced maintenance and energy consumption resulting in lower operating costs.
Advantages of the proposed invention when compared to conventional hydrocyclone equipment include but are not limited to the following;
No Pressure Vessel Containment, resulting in significant weight reduction;
Large flexibility and fluid turndown rates in flow rate and inlet oil concentration;
Low pressure drop requirements;
Easily adaptable to changing field operating conditions; and, Reduced energy consumption resulting in lower operating costs.
The ceramic molded apparatus of the present invention also offers benefits in corrosion and scale reduction to the process wetted surfaces along with the capability to combat erosion and wear.
When designed and arranged in a vertically stacked arrangement, the invention allows for the removal from service, if required, a row of hydrocyclone apparatus which can then be either cleaned, serviced or replaced without closing or deploying the entire 1o system. This cannot be accomplished with other hydrocyclone designs which utilize pressure vessels for their containment.
In a preferred aspect the present invention provides a process and devices for a liquid/liquid separation comprising of A triangular shaped ceramic main body section which is a cast or molded segment containing either a single or multiple arrangement of liquid/liquid separation chambers each of which contain three main sections for the separation to be completed within;
An inlet end or chamber (Fig. 2b);
A reject (oil) outlet departure end (Fig. 3b); and, An accept (water) outlet section. (Fig. 3b).
2o The invention may be constructed of industrial grade ceramic materials and made up of several different pieces in its construction and prior to final firing and finishing.
The ceramic main body section (Fig. 1 a) is a triangular shaped solid cast ceramic block section which has several separation chambers cast into it. The separation chambers (preferrably 3 chambers) are shaped into the ceramic block section prior to casting using metal molds (not shown).
The helical device (Figs. 6a, 6b, 6c and 6d) is the main part of the velocity generation section (Fig 1 a-2) is a separately cast piece which is inserted into each of the separation chambers prior to final firing and finishing.
A ceramic cover plate (Fig. 2a, 3a) is provided at each end of the main ceramic body section. Each separately cast ceramic cover plate is installed onto its respective end prior to final firing and finishing. The ceramic cover plates contain necessary cast shapes for the isolation and direction of fluids internally during the separation process.
1o A steel cover plate (Fig. Sa, Sb) is provided at each end of the main ceramic body section. The separately manufactured steel cover plate is installed onto its respective end after final firing and prior to final finishing. The steel cover plates are installed onto the ceramic main body section (Fig. 1 a) primarily to incorporate threaded process connections and strengthen the apparatus mechanically and structurally.
After all ceramic parts are installed onto the main ceramic body section, the apparatus undergoes a firing process where the apparatus is subject to an elevated temperature where all ceramic internal components are sintered and become fully bonded onto the main ceramic body section. Ceramic components bond at each ceramic to ceramic contact point. After firing has been completed, the ceramic main body section (complete with all of its components) is left to cool down awaiting the final finishing process.
In final finishing the present invention in one aspect utilizes a Fiberglass Reinforced Plastic finishing process which involves the following completion steps:
The steel cover plates (Fig 5a, 5b) are installed at their respective ends to the ends of the ceramic main body section with a glue or adhesive substance such as epoxy or some similar attaching compound;
The steel cover plates' thickness are governed by the internal design pressure constraints and can be adjusted for varying mechanical design pressure conditions; and, After the steel cover plates have been installed, the present invention utilizes a Fiberglass Reinforced Plastic Lamination System to completely cover the apparatus excluding piping and process connection points.
The Lamination Process serves the purpose of assisting in withstanding mechanical 1o design pressure both internally and externally to the apparatus as well as aiding in preventing mechanical damage to the exposed ceramic surfaces along the main body of the apparatus. The Lamination process involves a series of layered wraps of Fiberglass or similar material which includes a cloth material using a resin type liquid for bonding the cloth to each succeeding layer. There is no limit to the number of layers each apparatus employs.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein:
Zo Figure 1 a is a side elevation of a separation apparatus according to one embodiment of the present invention;
Figure lb is an end view of an inlet end of the apparatus of fig. la;
Figure 1 c is an end view of an outlet end of the apparatus of fig. 1 a;
Figure ld is a right hand (i.e. rear) perspective view of the apparatus of Fig la;
Figure 1 a is a left hand (i. e. front) elevation view of the apparatus of Fig 1 a;
Figure 2a shows a ceramic inlet cover plate at the inlet end (fig.lb);
Figure 2b is a cross-sectional view along line 2b of fig. 2a;
Figure 3a shows an outlet ceramic cover plate at the outlet end (fig. lc), as viewed in the direction of arrow 3a in fig. 3b, with a steel orifice assembly process connection removed;
Figure 3b is a cross-sectional view along line 3b of fig. 3a;
Figure 3c is a view from the back of the outlet end of fig. 3a, as indicated by arrow 3c in fig. 3b;
1o Figure 4a is a side elevation of a process tube of the fig. la separator apparatus, along line 4a of fig. 4b;
Figure 4b is an end view of the inlet end of the process tube of fig. 4a;
Figure 4c is an end view of the outlet end of the process tube of fig. 4a;
Figure 5a shows in detail a steel cover plate at the inlet end of the separator apparatus of fig. 1 a;
Figure 5b shows in detail a steel cover plate at the outlet end of the separator apparatus of fig. 1 a;
Figure 6a is a detailed view of a helix as shown in fig. 1 a, namely from the right side of the separator apparatus;
2o Figure 6b shows the helix of fig. la from the opposite, or left, side;
Figure 6c is an end view, from the front, of the helix of fig, 6a; and, Figure 6c is an end view, from the rear, of the helix of fig. 6a.
LIST
OF
REFERENCE
NUMBERS
IN
DRAWINGS
1. inlet connection 2. steel inlet end cover plate 3. ceramic inlet end cover plate 4. inlet openings 5. ceramic outlet end cover plate 10. separation apparatus 11. inlet chamber 12. velocity generating section l0 separation chamber 13.
14. outlet orifice 15, discharge chamber 16. helical device 17. hydrocyclone tubes ceramic housing 18.
19. inlet openings in 3 20. recessed openings in 3 21. finished end of 3 22. inlet end of 18 spaced openings in 16 23.
24. Y dimension of 16 25. X dimension of 16 26. locking mechanism of 16 27. slot openings in 18 28. outlet end of 10 29. exit orifice openings in 5 30. diametric transition of 16 31. end portion of separation chamber 13 33. steel outlet end cover plate 34. discharge outlet connection of 15 37. tapered end of 16 1o Terminology typically used with tank design is sometimes used in this description to define the fluids. For example, "overflow" refers to the lighter phase or less dense fluids and "underflow" refers to the heavier or denser phase liquid.
A first embodiment of the separation apparatus of the present invention (indicated by the reference numeral 10) is shown in Fig. 1 d and generally contains five separate sections, namely; an inlet chamber 11; a velocity generation section 12 containing a helical device 16; a separation chamber 13; an outlet orifice 14 (overflow); and a discharge chamber 15.
In one preferred version of the first embodiment three hydrocyclone tubes 17 are arranged in a triangular shape within a single main body section called a ceramic housing 18. This embodiment allows for the invention to be placed within a housing means for pressure containment. The apparatus can also operate without the use of a housing means and be self contained within the ceramic housing 18 with no need for pressure containment such as a pressure vessel for mechanical design pressures at or near 350 psig.
In Figures 1 d, 1 a the apparatus 10 is arranged in a triangular arrangement ceramic housing 18. Fig. ld is a right side perspective view of the apparatus and Fig.
le is a left hand side perspective view of the apparatus. The design flow of the apparatus 10 in Figure 1 d, 1 a is from right to left with an inlet feed fluid entering the invention through a tapped or threaded process connection on the right side and is referred to as the inlet connection 1. The inlet connection 1 is drilled and tapped into a steel (or other suitable metal or non-metal material) inlet end cover plate 2 at the dimensions shown in Fig. 5a.
To facilitate continuous flow into the inlet chamber section 11, a similar opening, namely the inlet opening 19, is molded or cast into a ceramic inlet end cover plate 3 at the 1o dimensions shown in Fig. 2a, 2b. The steel inlet cover plate 2 fits flush into a recessed opening 20 (see Figs. 2a, 2b) provided in the ceramic inlet end cover plate 3 where it is held in place by an epoxy or similar type of adhesive bonding system. When installed and finished the steel inlet end cover plate 2 is flush in outside dimension with the finished end 21 of the ceramic inlet end cover plate 3. After installation of the steel inlet end cover ~5 plate 2, the centerline dimension of the inlet connection 1 of the steel inlet cover plate 2 and the inlet opening 19 of the ceramic inlet end cover plate 3 should be equal or within manufacturers standard tolerance (Fig. 2b).
The ceramic inlet cover plate 3 is permanently bonded onto the parent surface of each of the hydrocyclone tubes 17 at each of the ceramic to ceramic contact points located 2o at the inlet end 22 of the apparatus 10 once the kiln firing of the final assembled apparatus is undertaken.
Inlet fluids) are fed into the hydrocyclone through the common inlet connection 1 and inlet opening 19 into the inlet chamber section 11 which is made from the space between the ceramic inlet end plate 3 and the inlet end 22 of the ceramic housing 18. The void space of the inlet chamber section 11 and the central location of the inlet connection 1 serves to assist in evenly distributing fluids to the three hydrocyclone tubes 17.
Fluids contact the center area of the inlet end 22 of the apparatus 10 and enter the hydrocyclone tubes 17 from the inlet chamber section 11 through inlet openings 4 located s at the inlet end 22 of each of the three hydrocyclone tubes 17. These inlet openings 4 are the machined or molded ends created from the end helicoidal dimension coordinates which creates a fluid void space that is cast, machined and/or molded into a helix shape of the installed helical device 16 located in the velocity generation section 12 of the apparatus 10.
1o Figures 6a, 6b show a right side and left side view of the helical device 16. Each of these Figs. 6a, 6b show an example of a helical device 16 with two revolutions machined or cast into the helical device 16. The number of revolutions required varies in different applications and increasing hydrocyclone tube diameter but a minimum of about two revolutions is necessary for sufficient velocity generation and distribution for most ~s two phase separation applications.
The x dimension 25 and the y dimension 24 of the helical device 16 are also variable for different applications. For example, applications involving high crude oil concentrations (above 1%) do not require the same velocity for the separation of oil from the water phase that a water containing 0.05% solids content requires for separation of its 2o solids. Varying the x dimension 25 and the y dimension 24 assists in easily designing a hydrocyclone for a given application without redesigning any further the equipment geometrically.
The helical device 16 is cast or molded separately from the remainder of the main ceramic housing 18. Upon completion of the molding of the helical device 16, it is inserted into the ceramic housing section 18. A locking mechanism 26 (see Fig.
4b) is also molded into the bottom of the top helical device 16, and into the top of the bottom helical devices 16. All three helical devices fit firmly into a slot opening 27 molded into the ceramic housing 18 to prevent movement of the helical devices) 16 inside the ceramic housing 18 during the remainder of manufacturing. The helical devices) 16 are permanently bonded onto the parent surface of each of the hydrocyclone tubes 17 at each of the ceramic to ceramic contact points located inside each of the hydrocyclone tubes 17 which are inside the ceramic housing 18 once the kiln firing of the final assembled apparatus is undertaken.
1o Fluid enters the helical device 16 and is then forced around a helicoidal void space openings 23 (shown in Fig. 1 d, 1 a and Figs. 6a, 6b) which are cast or molded into the helical device 16 through several turns of the helical device 16, causing a spinning or rotating action onto the fluids. The helical device 16 imparts velocity and centrifugal force onto the inlet feed liquids within the separation chamber 13.
Once the fluids) have been fully exposed to the rotational motion caused by the helical device 16, they are then sent off the end of the helical device 16 by a tapered end piece 37 which is cast, molded or machined into the end of the helical device 16 to direct the rotating fluids) in to the centerline area of the separation chamber 13 through a diametric transition 30 located after the helical device 16 and prior to the separation 2o chamber 13. The diametric transition 30 assists in the fluid separation by receiving the turbulent rotating liquids from the helical device 16 and aiding in the conservation and preservation of rotational velocity by directing this flow into a smaller diametric section referred to as the separation chamber 13. The turbulent flow from the helical device 16 will quickly become less turbulent once the fluids) are sent into the larger diameters and cross sectional areas present in the remaining hydrocyclone tubes) 17. The diametric transition 30 directs the fluids into the separation chamber 13 and assists in preserving rotational velocities.
After the fluids have been exposed to the helical path of the helical device 16 and s sent into the separation chamber 13 they continue to rotate and separate as they progress toward the outlet end 28 of the apparatus 10. The rotational motion of the liquids result ultimately in the formation of a central vortexing core. The centrifugal and centripetal forces imparted upon the liquids cause a separation of the two liquids.
Centrifugal Forces cause the heavier phase liquids to be sent outwardly and centripetal forces cause the to lighter phase liquids to be sent inwardly.
As the rotating liquids progress through the separation chamber 13 and toward the outlet end 28 of the apparatus 10, the higher density solid particulate and/or liquid droplets migrate to the outer diameter or radial portions of each of the individual hydrocyclone tube bodies 17. The separation of the two liquid phases or solids/liquid 15 phases improves as the fluids are subjected to an increase in revolutions.
It is the purpose of the separation chamber 13 to provide sufl'lcient surface area and residence time to allow the fluids to be exposed to a maximum of revolutions to maximize separation efficiency of each of the hydrocyclone tubes 17 and the apparatus 10. The separation chamber 13 may also vary in length and diameter depending upon application. It is preferred that a 20 ~~mum Length/Diameter (L/D) ratio be established at 10 for the separation chamber 13.
After the fluids have completed their rotational path within the separation chamber 13 they are then sent into the outlet end 28 of the apparatus 10. The outlet end 28 of the apparatus 10 consists of two separate paths for each of the separated liquid phases to depart the apparatus 10.
The first of these paths is the outlet orifice 14. The rotational action of the liquids combined with the centrifugal forces imparted upon these liquids forces the lower density light liquid phase inwardly toward to the center core of the hydrocyclone tube body 17 and, once at the outlet end 28 of the hydrocyclone tube length, it is removed from the center of the hydrocyclone tube 17 through a centrally located outlet orifice assembly 14 (see Fig. 1 d). The outlet orifice assembly 14 is a conduit which allows the exit of the lighter phase liquids from the apparatus 10. There is a single outlet orifice for each of the hydrocyclone tubes 17 located within the apparatus 10. The outlet orifice assembly 14 is a completely encased conduit which is only open at each of the ends. There is no expected 1o contact between the outer diameter flow liquids and the inner diameter flow liquids within the outlet orifice assembly 14. The size of the outlet orifice assembly 14 is dependent upon application and expected design conditions. Therefore the size of the outlet orifice assembly 14 is variable with application and size of apparatus 10.
The second of the fluid paths located at the outlet end 28 of the apparatus 10 is the discharge chamber 15 (Fig. 1 d). The discharge chamber 15 is a sectioned area within the apparatus 10 which is a space between an end portion 31 of the separation chamber 13 and a ceramic outlet end cover plate 5. The discharge chamber 15 is fed from the separation chamber and contains the heavier phase of the separated fluids. The heavier second phase liquid flows out of the hydrocyclone outer diameter or radial portion 2o through slotted exit orifice openings 29 (see Fig. 3a) which are cast into the ceramic outlet end plate 5, also located at the outlet end 28 of the apparatus. This liquid phase is briefly stored in the discharge chamber 15 prior to final discharge from the apparatus 10. The discharge chamber contains a discharge outlet connection 34 which can be located at the end of the apparatus 10 in the steel outlet end cover plate 33, or the discharge outlet connection 34 can be alternately located at the bottom of the discharge chamber 15 in cases where possible solids disposal is of concern.
After all ceramic parts are installed onto the main ceramic body section, the apparatus undergoes a firing process where the apparatus is subject to an elevated s temperature where all ceramic internal components are sintered and become fully bonded onto the main ceramic body section. Ceramic components bond at each ceramic to ceramic contact point. After firing has been completed, the ceramic main body section (complete with all of its components) is left to cool down prior to the final finishing process.
to In one aspect, the present invention utilizes a Fiberglass Reinforced Plastic finishing process which involves the following completion steps:
The Steel Cover Plates (Fig Sa, Sb) are installed at their respective ends to the ends of the ceramic main body section with a glue or adhesive substance such as epoxy or some similar attaching compound;
15 The Steel Cover Plates thickness are governed by the internal design pressure constraints and can be adjusted for varying mechanical design pressure conditions;
After the Steel Cover Plates have been installed, the present invention utilizes a Fiberglass Reinforced Plastic Lamination System to completely cover the apparatus, excluding piping and process connection points.
2o The Lamination Process serves the purpose of assisting in withstanding mechanical design pressure both internally and externally to the apparatus as well as aiding in preventing mechanical damage to the exposed ceramic surfaces along the main body of the apparatus. The Lamination process involves a series of layered wraps of Fiberglass or similar material which includes a cloth material which uses a resin type liquid for bonding the cloth to each succeeding layer. There is no limit to the number of layers each apparatus employs.
The above description is intended in an illustrative rather than a restrictive sense and variations to the specific configurations described may be apparent to skilled persons in adapting the present invention to specific applications. Such variations are intended to form part of the present invention insofar as they are within the spirit and scope of the claims below. For example, four or more hydrocyclone tubes 17 may be arranged within one ceramic housing 18, although this is not preferred for some practical reasons, such as increased weight, and difficulty in handling and manufacture.
FIELD OF THE INVENTION
The present invention relates to a molded or cast ceramic separation apparatus which causes centrifugal and centripetal forces to be imparted on an incoming fluid stream which could be made up of two differing liquids such as oil and water or a fluid containing a solids/liquid mixture.
to The apparatus may be designed with modifications to be used in solidslliquids separations involving suspended solids such as sediments and bacteria-like organisms for separation from source water for use in ships' ballast water or similar types of separation applications. It can also be designed for the separation of two differing liquid phases such as oil and water.
The invention is designed to be used to remove large amounts of higher density water from an incoming process stream or it can be used for water cleanup applications.
As well, it can be used where there are two liquids of varying density which require a separation of the two liquids involved.
2o BACKGROUND OF THE INVENTION
There are two areas of interest and potential application of the invention.
The first is the separation of oil and water in oilfield production operations and the second is the separation of solids from a sourcewater for ships ballast water to reduce the presence of solids and/or the transit and exchange of Aquatic Nuisance Species.
Produced Water Application of the Invention Presently in oilfield operations it is necessary to handle large volumes of produced water to recover hydrocarbons. Horizontally drilled wells, aging pools and reservoirs which utilize water flooding techniques often become affected areas. The basic result of these factors produces crude oil emulsion streams which contain increasingly higher water/oil ratios as opposed to initial oil production that typically yield lower water/oil ratios.
There is a requirement in oilfield operations for an apparatus and/or process for the separation of a highly water laden fluid, but which does not rely entirely upon gravity 1o settling as its main vehicle for the separation of the two liquids involved. A separation device which accelerates the separation of the two liquids and addresses environmental concerns, increases the producing life of a reservoir while ef~lciently handling large volumes of produced water prior to disposal and/or reinjection, is particularly desirable.
It must be stated, however, that the present invention will not solely be directed toward oilfield types of operations but also in any application where there is a requirement to separate two substances of varying density, or what is referred to either as a "liquid/liquid" separation or a "solids/liquid" separation. The technology that is presented utilizes accepted scientific principles of physics in the separation of fluids.
The current method of gravity separation uses Stokes Law, which states that "through time an emulsion fluid of oil and water will separate with the effect of gravity"
and is based on mass (droplet size) and the proportional density difference between oil and water which governs the falling or settling velocity. Basically, the lighter phase fluids will rise to the top and the heavier or denser phase fluids will fall to the bottom. Residence time and/or general gravity settling volume is important to these types of systems, and therefore heat and chemicals are added to accelerate emulsion separation in conventional gravity settling systems. The proposed invention differs from conventional gravity settling systems because it uses centripetal and centrifugal forces to cause separation of the two liquids as opposed to gravity settling principles as outlined in Stokes' Law.
The principles of liquid/liquid separation using centrifugal and centripetal forces are relatively new and it can be stated that each liquid/liquid separation requires specific attention in its design. Centrifi.~gal or cyclonic separations normally take one to two seconds to perform and can usually be accomplished with reduced heat or thermal assistance or in many cases a significant reduction in treating and demulsifying chemicals.
1o Similar technology has been used successfully in other areas of the petroleum industry, primarily on off shore water cleanup (deoiling) applications.
Other hydrocyclone inventions use similar accepted cyclonic principles, but the proposed invention is unique in many respects from the existing hydrocyclone technology. The proposed invention can successfi~lly operate at low or high operating differential pressures, and thus the need for other supporting equipment such as pumps is reduced. The existing operating pressures at mainland or offshore production facilities is well within the operating parameters of this invention.
Ballast Water Application of the Invention 2o Ships use ballast water worldwide to operate safely and successfixlly.
Among other uses, ballast aids propulsion and maneuverability by providing weight to submerge the rudder and reduce the amount of exposed hull surface. It also provides for greater stability and reduces stresses on the hull. Water began to be the predominant form of ballast from around the 1880s onward, replacing rocks, sand and other heavy, solid materials.
When a ship takes on ballast, normally in coastal waters outside a port to make up for weight lost after unloading cargo, it also takes on the available solids fraction of the source water (which typically contains sediments, minerals and other suspended solids) along with thousands of microscopic organisms, including plankton species, the planktonic life stages of other marine species, and pathogens. These solids and organisms are then transported in the ship's ballast tank and released when the ballast is discharged when the ship arrives at another port of call.
to The favored method for reducing the risk of introducing alien species into aquatic environments is changing ballast far out at sea. In this technique, ballast water loaded in port or taken on board while transiting inshore waters is changed with Open Ocean water during passage between ports of call. This method is usually effective because most freshwater, estuarine and inshore coastal organisms cannot survive when discharged into the ocean environment. However, exchanging ballast at sea is not always a practical solution because one of the main functions of ballast is to insure the stability of ships at sea, and so exchanging ballast while in transit may threaten the vessel's safety. Hence, it would be desireable to devise ways to eliminate organisms from ballast water as it is taken on board or discharged.
2o Further, because of the presence of the solids in source water, solids will collect in the ballast tanks over time and substantially reduce a ships' cargo carrying capacity.
Because of the large amount of ballast water required by ships, and the relatively high density of the solids fraction constituents as compared to the source water, it does not take a high concentration of solids to equate to as much as 20 to 50 tons of lost cargo carrying capacity per voyage. Source water containing a total suspended solids (TSS) fraction as low as 0.02% can yield a total solids intake of approximately 27 to 30 tons for an average sized cargo ship. Because of the diversity of ocean going vessels, the reduction of solids and the subsequent preservation of approximately 30 tons of cargo carrying capability warrants concern. Solids buildup in ballast water tanks costs ship owners and operators millions of dollars annually in maintenance costs and lost cargo.
Prior Separators The performance of all mechanical gravity settling separators is affected by the 1o same physical parameters. Gravity separators (i.e. skimmers, gas flotation cells and coalescing vessels) can be understood through Stokes Law, which governs the velocity at which a droplet will travel through a continuous phase fluid. This velocity is directly proportional to the density difference between the two liquid phases. The force of gravity usually dictates the size of the droplet's movement. The velocity is inversely proportional to the relative viscosity of the droplet in the continuous phase.
Stokes Law Vt= 1,488 g DPZ (P, - Pi) 18 p.
2o where:
~ Vt =Terminal Settling Velocity (ft/sec.) ~ g - local acceleration due to gravity (32.2 ft/sec.2 ) ~ Dp = Droplet or particle diameter (ft.) ~ p, = liquid phase density continuous phase (Ib/ft3 ~ p2= liquid phase density droplet or particle (Ib/ft3) . P, = viscosity of continuous phase (cp) Separators, which utilize gravity settling, residence time and Stokes Law principles in their design fail to meet the size and weight constraints for a ballast water process application. Filtration vessels also use many of the same separation principles identified in Stokes Law and further involve the exposure of the fluids to a minimum surface area, which adversely affects equipment size and weight. Hence, since ballast water separation applications are subject to the space constraints of ocean going vessels, gravity based settling equipment is virtually eliminated from such application.
Other laws that involve the same variables as Stokes Law describe separators that use centrifugal force such as hydrocyclones, rather than gravity. In a typical liquid/liquid to separation, the conventional reverse flow hydrocyclone escapes Stokes Law in two ways.
First, the mixture is caused to spin inside the unit generating a centrifugal force to drive a less dense droplet through a continuous fluid (denser) phase. This is done simply with pressure, and requires no moving parts. Second, the hydrocyclone has a small diameter resulting in a very short distance in which the less dense droplet must travel in order to be separated from the denser phase. The end result is that the system has a residence time of less than two seconds, compared to the range of six to sixty minutes usually required for gravity based separation systems. This means that it need not be of a large size.
As the fluids pass though the hydrocyclone, the equipment's internal features cause the fluid to spin. High centripetal forces cause the denser phase to be sent outwards while 2o the lighter less dense phase is displaced to the center of the tube body and resulting internal vortex. In reverse flow designs, the stream typically flows through an internal liner. The geometry maintains the vortex and permits the water stream to flow out into a pressure vessel housing, while causing the central core to flow in the reverse direction.
The high centripetal forces required to perform liquid/liquid separation in the short time that the fluid remains within the equipment are produced at the expense of system pressure.
Drawbacks to Existing Hydrocyclone Technology s The reverse flow type of hydrocyclone is not entirely free of compromises.
It does require sufficient dii~erential pressure to operate, typically SOpsig. to 80psig. It is claimed that the more pressure which is available, the more cost effective this type of system becomes due to increased throughput. However, by increasing the available pressure, one must take into account the additional capital and equipment costs especially in ballast 1o water applications involving 3,000 m3/hr to 5,000 m3/hr. flow capacities.
From conventional design theory, it can be surmised that reverse flow hydrocyclone design relies heavily upon the generation of velocity causing the necessary centrifugal forces to be imparted upon the particles to be separated. This design accomplishes this through its geometric configuration. Typically cone shaped, the reverse ~s flow hydrocyclone requires that one of the separated phases be directed backward or in a reverse flow to the inlet flow. By doing so, there is a separate force acting in reverse to the inlet velocities and forces, causing a necessity to generate velocities above these reverse flows which increases the pressure requirements causing a potential inefficiency in the separation.
2o Reverse flow technology requires the creation of a central vortex core (as do all hydrocyclones), but by reversing the flow of this phase there is minimal area and volume in which the separated phase has to commingle, flocculate and discharge from the hydrocyclone body. This design characteristic is a function of the design geometry of the reverse flow hydrocyclone and is why this design of hydrocyclone is so dependent upon the generation of velocity to accomplish its separation.
Hydrocyclone manufacturers claim generally that the centrifugal forces imparted on solids particles are in the order of 10,000 g's. During our research phase, we discovered that there was the possibility that centrifugal forces in this range were responsible for the shearing of oil droplets and that the reverse flow hydrocyclone design may be causing some stabilization to crude oil emulsions as a result. Ballast water applications, for example, involve the separation of solids particles which may be able to withstand centrifugal forces of this magnitude but there is a possibility that imparting an 1o excess of force upon small solids particles would result in further shearing these particles and causing them to be non-recoverable.
There have been many instances where reverse flow hydrocyclone designs have been unsuccessful. The standard solution to increasing separation efficiency was to increase velocity and subsequently increasing centrifugal forces. In most of these instances there was neither an increased efficiency nor a change in performance. This brings forth the question of velocities and whether it is necessary to impart large centrifugal forces in separations involving solids particles in the range of 5 microns to 100 microns.
Further studies into the types of solids particles involved in ballast water 2o separations reveal the solids fraction in source water contains mineral and ash constituents. In some cases, the 0 - 50 micron particles represent up to 25%
of the solids fraction. If the separation efficiency of a reverse flow hydrocyclone is approximately 50%
at this size range there is a significant amount of solids being left in the discharge stream and being sent to the ballast water tanks.
_g_ This brings to light an uncertainty of whether the reverse flow hydrocyclone design or configuration is capable of being combined successfully into an existing ballast water-treating scenario. Most ships do not have pumping equipment that can provide sufficient pressure to drive this type of hydrocyclone design while maintaining acceptable ballast water intake rates. Subsequently, the use of existing ballast water pumps would result in operating at an elevated pressure, which would reduce the pumping capacity and extend ballast water cycles. The alternative to the use of existing equipment is to re-equip all ocean-going vessels with new pumping equipment.
It is not practical to place a reverse flow hydrocyclone in a ballast water system.
1o While this is a possible form of satisfying ballast water separations, it has the potential to unnecessarily add to the complexity, size, weight, operating and maintenance requirements of a ballast water separation system.
What is desired therefore is a ceramic cast or molded hydrocyclone apparatus which overcomes the limitations and disadvantages of other prior art hydrocyclones.
Preferably the hydrocyclone apparatus should be cast or molded from a material such as ceramic, fiberglass or an industrial grade plastic which is capable of providing pressure containment, seamless internal construction and smooth flow properties of process fluids) 2o throughout its entire length.
The present invention has shown in field and laboratory test trials the ability to efficiently and effectively separate two phase liquids at reduced operating and differential pressures when compared to prior art hydrocyclone technology.
If required, the preferred embodiment is capable of being installed as a separate apparatus or in a multiple arrangement which could increase capacity in certain applications.
The invention is designed to be manufactured in a wide range of diameters and lengths to satisfy capacity and varying application requirements. In so doing, the invention would substantially reduce equipment costs and reduce equipment size and weight limitations.
Advantages l0 Existing hydrocyclone designs rely on pressure vessel containment to operate in the applications for which they are designed. The present invention uses a ceramic molded apparatus which is able to withstand the necessary operating pressures and therefore eliminate the need for a pressure vessel entirely.
Other advantages of the proposed invention when compared to conventional gravity settling equipment includes but is not limited to the following:
Minimal residence time, resulting in significant weight and volume reduction;
High efficiency when compared with conventional settling tanks or pressure vessels;
Large flexibility in flow rate and inlet oil concentration;
Easily adaptable to changing field operating conditions; and, 2o Reduced maintenance and energy consumption resulting in lower operating costs.
Advantages of the proposed invention when compared to conventional hydrocyclone equipment include but are not limited to the following;
No Pressure Vessel Containment, resulting in significant weight reduction;
Large flexibility and fluid turndown rates in flow rate and inlet oil concentration;
Low pressure drop requirements;
Easily adaptable to changing field operating conditions; and, Reduced energy consumption resulting in lower operating costs.
The ceramic molded apparatus of the present invention also offers benefits in corrosion and scale reduction to the process wetted surfaces along with the capability to combat erosion and wear.
When designed and arranged in a vertically stacked arrangement, the invention allows for the removal from service, if required, a row of hydrocyclone apparatus which can then be either cleaned, serviced or replaced without closing or deploying the entire 1o system. This cannot be accomplished with other hydrocyclone designs which utilize pressure vessels for their containment.
In a preferred aspect the present invention provides a process and devices for a liquid/liquid separation comprising of A triangular shaped ceramic main body section which is a cast or molded segment containing either a single or multiple arrangement of liquid/liquid separation chambers each of which contain three main sections for the separation to be completed within;
An inlet end or chamber (Fig. 2b);
A reject (oil) outlet departure end (Fig. 3b); and, An accept (water) outlet section. (Fig. 3b).
2o The invention may be constructed of industrial grade ceramic materials and made up of several different pieces in its construction and prior to final firing and finishing.
The ceramic main body section (Fig. 1 a) is a triangular shaped solid cast ceramic block section which has several separation chambers cast into it. The separation chambers (preferrably 3 chambers) are shaped into the ceramic block section prior to casting using metal molds (not shown).
The helical device (Figs. 6a, 6b, 6c and 6d) is the main part of the velocity generation section (Fig 1 a-2) is a separately cast piece which is inserted into each of the separation chambers prior to final firing and finishing.
A ceramic cover plate (Fig. 2a, 3a) is provided at each end of the main ceramic body section. Each separately cast ceramic cover plate is installed onto its respective end prior to final firing and finishing. The ceramic cover plates contain necessary cast shapes for the isolation and direction of fluids internally during the separation process.
1o A steel cover plate (Fig. Sa, Sb) is provided at each end of the main ceramic body section. The separately manufactured steel cover plate is installed onto its respective end after final firing and prior to final finishing. The steel cover plates are installed onto the ceramic main body section (Fig. 1 a) primarily to incorporate threaded process connections and strengthen the apparatus mechanically and structurally.
After all ceramic parts are installed onto the main ceramic body section, the apparatus undergoes a firing process where the apparatus is subject to an elevated temperature where all ceramic internal components are sintered and become fully bonded onto the main ceramic body section. Ceramic components bond at each ceramic to ceramic contact point. After firing has been completed, the ceramic main body section (complete with all of its components) is left to cool down awaiting the final finishing process.
In final finishing the present invention in one aspect utilizes a Fiberglass Reinforced Plastic finishing process which involves the following completion steps:
The steel cover plates (Fig 5a, 5b) are installed at their respective ends to the ends of the ceramic main body section with a glue or adhesive substance such as epoxy or some similar attaching compound;
The steel cover plates' thickness are governed by the internal design pressure constraints and can be adjusted for varying mechanical design pressure conditions; and, After the steel cover plates have been installed, the present invention utilizes a Fiberglass Reinforced Plastic Lamination System to completely cover the apparatus excluding piping and process connection points.
The Lamination Process serves the purpose of assisting in withstanding mechanical 1o design pressure both internally and externally to the apparatus as well as aiding in preventing mechanical damage to the exposed ceramic surfaces along the main body of the apparatus. The Lamination process involves a series of layered wraps of Fiberglass or similar material which includes a cloth material using a resin type liquid for bonding the cloth to each succeeding layer. There is no limit to the number of layers each apparatus employs.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein:
Zo Figure 1 a is a side elevation of a separation apparatus according to one embodiment of the present invention;
Figure lb is an end view of an inlet end of the apparatus of fig. la;
Figure 1 c is an end view of an outlet end of the apparatus of fig. 1 a;
Figure ld is a right hand (i.e. rear) perspective view of the apparatus of Fig la;
Figure 1 a is a left hand (i. e. front) elevation view of the apparatus of Fig 1 a;
Figure 2a shows a ceramic inlet cover plate at the inlet end (fig.lb);
Figure 2b is a cross-sectional view along line 2b of fig. 2a;
Figure 3a shows an outlet ceramic cover plate at the outlet end (fig. lc), as viewed in the direction of arrow 3a in fig. 3b, with a steel orifice assembly process connection removed;
Figure 3b is a cross-sectional view along line 3b of fig. 3a;
Figure 3c is a view from the back of the outlet end of fig. 3a, as indicated by arrow 3c in fig. 3b;
1o Figure 4a is a side elevation of a process tube of the fig. la separator apparatus, along line 4a of fig. 4b;
Figure 4b is an end view of the inlet end of the process tube of fig. 4a;
Figure 4c is an end view of the outlet end of the process tube of fig. 4a;
Figure 5a shows in detail a steel cover plate at the inlet end of the separator apparatus of fig. 1 a;
Figure 5b shows in detail a steel cover plate at the outlet end of the separator apparatus of fig. 1 a;
Figure 6a is a detailed view of a helix as shown in fig. 1 a, namely from the right side of the separator apparatus;
2o Figure 6b shows the helix of fig. la from the opposite, or left, side;
Figure 6c is an end view, from the front, of the helix of fig, 6a; and, Figure 6c is an end view, from the rear, of the helix of fig. 6a.
LIST
OF
REFERENCE
NUMBERS
IN
DRAWINGS
1. inlet connection 2. steel inlet end cover plate 3. ceramic inlet end cover plate 4. inlet openings 5. ceramic outlet end cover plate 10. separation apparatus 11. inlet chamber 12. velocity generating section l0 separation chamber 13.
14. outlet orifice 15, discharge chamber 16. helical device 17. hydrocyclone tubes ceramic housing 18.
19. inlet openings in 3 20. recessed openings in 3 21. finished end of 3 22. inlet end of 18 spaced openings in 16 23.
24. Y dimension of 16 25. X dimension of 16 26. locking mechanism of 16 27. slot openings in 18 28. outlet end of 10 29. exit orifice openings in 5 30. diametric transition of 16 31. end portion of separation chamber 13 33. steel outlet end cover plate 34. discharge outlet connection of 15 37. tapered end of 16 1o Terminology typically used with tank design is sometimes used in this description to define the fluids. For example, "overflow" refers to the lighter phase or less dense fluids and "underflow" refers to the heavier or denser phase liquid.
A first embodiment of the separation apparatus of the present invention (indicated by the reference numeral 10) is shown in Fig. 1 d and generally contains five separate sections, namely; an inlet chamber 11; a velocity generation section 12 containing a helical device 16; a separation chamber 13; an outlet orifice 14 (overflow); and a discharge chamber 15.
In one preferred version of the first embodiment three hydrocyclone tubes 17 are arranged in a triangular shape within a single main body section called a ceramic housing 18. This embodiment allows for the invention to be placed within a housing means for pressure containment. The apparatus can also operate without the use of a housing means and be self contained within the ceramic housing 18 with no need for pressure containment such as a pressure vessel for mechanical design pressures at or near 350 psig.
In Figures 1 d, 1 a the apparatus 10 is arranged in a triangular arrangement ceramic housing 18. Fig. ld is a right side perspective view of the apparatus and Fig.
le is a left hand side perspective view of the apparatus. The design flow of the apparatus 10 in Figure 1 d, 1 a is from right to left with an inlet feed fluid entering the invention through a tapped or threaded process connection on the right side and is referred to as the inlet connection 1. The inlet connection 1 is drilled and tapped into a steel (or other suitable metal or non-metal material) inlet end cover plate 2 at the dimensions shown in Fig. 5a.
To facilitate continuous flow into the inlet chamber section 11, a similar opening, namely the inlet opening 19, is molded or cast into a ceramic inlet end cover plate 3 at the 1o dimensions shown in Fig. 2a, 2b. The steel inlet cover plate 2 fits flush into a recessed opening 20 (see Figs. 2a, 2b) provided in the ceramic inlet end cover plate 3 where it is held in place by an epoxy or similar type of adhesive bonding system. When installed and finished the steel inlet end cover plate 2 is flush in outside dimension with the finished end 21 of the ceramic inlet end cover plate 3. After installation of the steel inlet end cover ~5 plate 2, the centerline dimension of the inlet connection 1 of the steel inlet cover plate 2 and the inlet opening 19 of the ceramic inlet end cover plate 3 should be equal or within manufacturers standard tolerance (Fig. 2b).
The ceramic inlet cover plate 3 is permanently bonded onto the parent surface of each of the hydrocyclone tubes 17 at each of the ceramic to ceramic contact points located 2o at the inlet end 22 of the apparatus 10 once the kiln firing of the final assembled apparatus is undertaken.
Inlet fluids) are fed into the hydrocyclone through the common inlet connection 1 and inlet opening 19 into the inlet chamber section 11 which is made from the space between the ceramic inlet end plate 3 and the inlet end 22 of the ceramic housing 18. The void space of the inlet chamber section 11 and the central location of the inlet connection 1 serves to assist in evenly distributing fluids to the three hydrocyclone tubes 17.
Fluids contact the center area of the inlet end 22 of the apparatus 10 and enter the hydrocyclone tubes 17 from the inlet chamber section 11 through inlet openings 4 located s at the inlet end 22 of each of the three hydrocyclone tubes 17. These inlet openings 4 are the machined or molded ends created from the end helicoidal dimension coordinates which creates a fluid void space that is cast, machined and/or molded into a helix shape of the installed helical device 16 located in the velocity generation section 12 of the apparatus 10.
1o Figures 6a, 6b show a right side and left side view of the helical device 16. Each of these Figs. 6a, 6b show an example of a helical device 16 with two revolutions machined or cast into the helical device 16. The number of revolutions required varies in different applications and increasing hydrocyclone tube diameter but a minimum of about two revolutions is necessary for sufficient velocity generation and distribution for most ~s two phase separation applications.
The x dimension 25 and the y dimension 24 of the helical device 16 are also variable for different applications. For example, applications involving high crude oil concentrations (above 1%) do not require the same velocity for the separation of oil from the water phase that a water containing 0.05% solids content requires for separation of its 2o solids. Varying the x dimension 25 and the y dimension 24 assists in easily designing a hydrocyclone for a given application without redesigning any further the equipment geometrically.
The helical device 16 is cast or molded separately from the remainder of the main ceramic housing 18. Upon completion of the molding of the helical device 16, it is inserted into the ceramic housing section 18. A locking mechanism 26 (see Fig.
4b) is also molded into the bottom of the top helical device 16, and into the top of the bottom helical devices 16. All three helical devices fit firmly into a slot opening 27 molded into the ceramic housing 18 to prevent movement of the helical devices) 16 inside the ceramic housing 18 during the remainder of manufacturing. The helical devices) 16 are permanently bonded onto the parent surface of each of the hydrocyclone tubes 17 at each of the ceramic to ceramic contact points located inside each of the hydrocyclone tubes 17 which are inside the ceramic housing 18 once the kiln firing of the final assembled apparatus is undertaken.
1o Fluid enters the helical device 16 and is then forced around a helicoidal void space openings 23 (shown in Fig. 1 d, 1 a and Figs. 6a, 6b) which are cast or molded into the helical device 16 through several turns of the helical device 16, causing a spinning or rotating action onto the fluids. The helical device 16 imparts velocity and centrifugal force onto the inlet feed liquids within the separation chamber 13.
Once the fluids) have been fully exposed to the rotational motion caused by the helical device 16, they are then sent off the end of the helical device 16 by a tapered end piece 37 which is cast, molded or machined into the end of the helical device 16 to direct the rotating fluids) in to the centerline area of the separation chamber 13 through a diametric transition 30 located after the helical device 16 and prior to the separation 2o chamber 13. The diametric transition 30 assists in the fluid separation by receiving the turbulent rotating liquids from the helical device 16 and aiding in the conservation and preservation of rotational velocity by directing this flow into a smaller diametric section referred to as the separation chamber 13. The turbulent flow from the helical device 16 will quickly become less turbulent once the fluids) are sent into the larger diameters and cross sectional areas present in the remaining hydrocyclone tubes) 17. The diametric transition 30 directs the fluids into the separation chamber 13 and assists in preserving rotational velocities.
After the fluids have been exposed to the helical path of the helical device 16 and s sent into the separation chamber 13 they continue to rotate and separate as they progress toward the outlet end 28 of the apparatus 10. The rotational motion of the liquids result ultimately in the formation of a central vortexing core. The centrifugal and centripetal forces imparted upon the liquids cause a separation of the two liquids.
Centrifugal Forces cause the heavier phase liquids to be sent outwardly and centripetal forces cause the to lighter phase liquids to be sent inwardly.
As the rotating liquids progress through the separation chamber 13 and toward the outlet end 28 of the apparatus 10, the higher density solid particulate and/or liquid droplets migrate to the outer diameter or radial portions of each of the individual hydrocyclone tube bodies 17. The separation of the two liquid phases or solids/liquid 15 phases improves as the fluids are subjected to an increase in revolutions.
It is the purpose of the separation chamber 13 to provide sufl'lcient surface area and residence time to allow the fluids to be exposed to a maximum of revolutions to maximize separation efficiency of each of the hydrocyclone tubes 17 and the apparatus 10. The separation chamber 13 may also vary in length and diameter depending upon application. It is preferred that a 20 ~~mum Length/Diameter (L/D) ratio be established at 10 for the separation chamber 13.
After the fluids have completed their rotational path within the separation chamber 13 they are then sent into the outlet end 28 of the apparatus 10. The outlet end 28 of the apparatus 10 consists of two separate paths for each of the separated liquid phases to depart the apparatus 10.
The first of these paths is the outlet orifice 14. The rotational action of the liquids combined with the centrifugal forces imparted upon these liquids forces the lower density light liquid phase inwardly toward to the center core of the hydrocyclone tube body 17 and, once at the outlet end 28 of the hydrocyclone tube length, it is removed from the center of the hydrocyclone tube 17 through a centrally located outlet orifice assembly 14 (see Fig. 1 d). The outlet orifice assembly 14 is a conduit which allows the exit of the lighter phase liquids from the apparatus 10. There is a single outlet orifice for each of the hydrocyclone tubes 17 located within the apparatus 10. The outlet orifice assembly 14 is a completely encased conduit which is only open at each of the ends. There is no expected 1o contact between the outer diameter flow liquids and the inner diameter flow liquids within the outlet orifice assembly 14. The size of the outlet orifice assembly 14 is dependent upon application and expected design conditions. Therefore the size of the outlet orifice assembly 14 is variable with application and size of apparatus 10.
The second of the fluid paths located at the outlet end 28 of the apparatus 10 is the discharge chamber 15 (Fig. 1 d). The discharge chamber 15 is a sectioned area within the apparatus 10 which is a space between an end portion 31 of the separation chamber 13 and a ceramic outlet end cover plate 5. The discharge chamber 15 is fed from the separation chamber and contains the heavier phase of the separated fluids. The heavier second phase liquid flows out of the hydrocyclone outer diameter or radial portion 2o through slotted exit orifice openings 29 (see Fig. 3a) which are cast into the ceramic outlet end plate 5, also located at the outlet end 28 of the apparatus. This liquid phase is briefly stored in the discharge chamber 15 prior to final discharge from the apparatus 10. The discharge chamber contains a discharge outlet connection 34 which can be located at the end of the apparatus 10 in the steel outlet end cover plate 33, or the discharge outlet connection 34 can be alternately located at the bottom of the discharge chamber 15 in cases where possible solids disposal is of concern.
After all ceramic parts are installed onto the main ceramic body section, the apparatus undergoes a firing process where the apparatus is subject to an elevated s temperature where all ceramic internal components are sintered and become fully bonded onto the main ceramic body section. Ceramic components bond at each ceramic to ceramic contact point. After firing has been completed, the ceramic main body section (complete with all of its components) is left to cool down prior to the final finishing process.
to In one aspect, the present invention utilizes a Fiberglass Reinforced Plastic finishing process which involves the following completion steps:
The Steel Cover Plates (Fig Sa, Sb) are installed at their respective ends to the ends of the ceramic main body section with a glue or adhesive substance such as epoxy or some similar attaching compound;
15 The Steel Cover Plates thickness are governed by the internal design pressure constraints and can be adjusted for varying mechanical design pressure conditions;
After the Steel Cover Plates have been installed, the present invention utilizes a Fiberglass Reinforced Plastic Lamination System to completely cover the apparatus, excluding piping and process connection points.
2o The Lamination Process serves the purpose of assisting in withstanding mechanical design pressure both internally and externally to the apparatus as well as aiding in preventing mechanical damage to the exposed ceramic surfaces along the main body of the apparatus. The Lamination process involves a series of layered wraps of Fiberglass or similar material which includes a cloth material which uses a resin type liquid for bonding the cloth to each succeeding layer. There is no limit to the number of layers each apparatus employs.
The above description is intended in an illustrative rather than a restrictive sense and variations to the specific configurations described may be apparent to skilled persons in adapting the present invention to specific applications. Such variations are intended to form part of the present invention insofar as they are within the spirit and scope of the claims below. For example, four or more hydrocyclone tubes 17 may be arranged within one ceramic housing 18, although this is not preferred for some practical reasons, such as increased weight, and difficulty in handling and manufacture.
Claims
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An apparatus and process as described and illustrated herein.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002252306A CA2252306A1 (en) | 1998-10-30 | 1998-10-30 | Liquid separator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002252306A CA2252306A1 (en) | 1998-10-30 | 1998-10-30 | Liquid separator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2252306A1 true CA2252306A1 (en) | 2000-04-30 |
Family
ID=29425574
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002252306A Abandoned CA2252306A1 (en) | 1998-10-30 | 1998-10-30 | Liquid separator |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2252306A1 (en) |
-
1998
- 1998-10-30 CA CA002252306A patent/CA2252306A1/en not_active Abandoned
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued | ||
| FZDE | Discontinued |
Effective date: 20021030 |