Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
  • B03D1/00—Flotation
  • B03D1/02—Froth-flotation processes
• • 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
  • B01D17/0205—Separation of non-miscible liquids by gas bubbles or moving solids
• • 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
  • B01D17/0208—Separation of non-miscible liquids by sedimentation
  • B01D17/0211—Separation of non-miscible liquids by sedimentation with baffles
• • 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
  • B01D17/0208—Separation of non-miscible liquids by sedimentation
  • B01D17/0214—Separation of non-miscible liquids by sedimentation with removal of one of the phases
• • 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
  • B01D17/04—Breaking emulsions
  • B01D17/045—Breaking emulsions with coalescers
• • 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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
  • B03D1/00—Flotation
  • B03D1/14—Flotation machines
  • B03D1/1406—Flotation machines with special arrangement of a plurality of flotation cells, e.g. positioning a flotation cell inside another
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
  • B03D1/00—Flotation
  • B03D1/14—Flotation machines
  • B03D1/1412—Flotation machines with baffles, e.g. at the wall for redirecting settling solids
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
  • B03D1/00—Flotation
  • B03D1/14—Flotation machines
  • B03D1/1443—Feed or discharge mechanisms for flotation tanks
  • B03D1/1456—Feed mechanisms for the slurry
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
  • B03D1/00—Flotation
  • B03D1/14—Flotation machines
  • B03D1/1493—Flotation machines with means for establishing a specified flow pattern
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
  • B03D1/00—Flotation
  • B03D1/14—Flotation machines
  • B03D1/24—Pneumatic
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/24—Treatment of water, waste water, or sewage by flotation
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2101/00—Nature of the contaminant
  • C02F2101/30—Organic compounds
  • C02F2101/32—Hydrocarbons, e.g. oil
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/10—Nature of the water, waste water, sewage or sludge to be treated from quarries or from mining activities
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
  • C02F2103/36—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from the manufacture of organic compounds
  • C02F2103/365—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from the manufacture of organic compounds from petrochemical industry (e.g. refineries)

Definitions

• the invention relates to gas flotation tanks for separating hydrocarbons from produced water and more specifically to gas flotation tanks with reduced structural and internal piping that prevent, reduce or at least mitigate short circuiting.
• Gas flotation tanks are used to separate unwanted phases or contaminants such as hydrocarbons from produced water generally by allowing or facilitating the rising of the unwanted phases or contaminants to the surface of produced water. The hydrocarbons may then be removed via skimming of the surface of the produced water.
• One typical gas flotation tank comprises of a number of chambers separated by a dividing wall but in fluid communication with each other. During operation, produced water is input into the tank and a rotational current is generated promoting hydrocarbon to rise to the surface of the water in the tank while forcing cleaner more purified water towards the bottom of the tank. By passing the lower water to an adjacent chamber via a fluid communication port, each successive chamber contains produced water having a lower content of hydrocarbons until a desired purity level is reached and the water is output from the gas flotation tank.
• one gas flotation tank includes an interconnecting pipe to connect the chambers in series without creating a short circuit from the inlet to the outlet.
• the interconnecting pipe is located in such a way that the water considered to be cleanest is taken from one chamber to the next, released near the surface, and dispersed in a fashion (in conjunction with a water weir) to create a flow pattern and velocities that facilitate skimming of the surface hydrocarbon towards an oil skimming trough.
• the interconnecting pipe also acts as a region in which“micro-bubbles” may be introduced before entering subsequent chambers to ensure even mixing with flow going into each chamber.
• the interconnecting pipe allows for, in an upset condition, an uncontrolled increase or decrease inlet flow, resulting in a large level difference between chambers that can collapse the internal walls hence requiring a need to heavily reinforce the tank.
• the interconnecting pipe size can be increased.
• such an increase can obstruct the flow pattern within the tank as well as reduce the working volume of the chamber thus rendering the tank less efficient.
• such an interconnecting pipe is limited by standard pipe and rolled plate sizes and associated costs.
• filling and draining the tank is a delicate process that requires careful monitoring of the level in each chamber.
• a serpentine tank includes a number of chambers, each chamber separated by a partition wherein a portion of the partition is a perforated plate or opening, allowing for the balancing of the chambers.
• a serpentine tank allows only for horizontal flow through the tank, wherein gravity and time are used for the separation of the unwanted phases.
• the fluid in a serpentine tank flows substantially in one direction inside the chamber (lengthwise) and exits the chamber through the perforated plate, or open section, to the adjacent chamber where it flows horizontally the length of that chamber, repeating for as many chambers as is provided in a given tank, hence the term“serpentine”.
• This pattern of going end to end also creates the requirement for individual skimming points in each chamber, which also requires additional nozzles on the tank, external piping, and valves for removing the unwanted phases.
• a gas flotation tank for separating contaminants from fluid includes a series of adjacent chambers which impart a rotational current therein through the use of a sloped weir in each chamber. Each chamber is separated from a skim oil trough by a skimming weir over which the contaminants pass. Each adjacent chamber is fluidly connected via an interconnecting passage that allows for the transfer of reduced contaminant fluid to an adjacent chamber for further contaminant reduction.
• An alternating setup of fluid passages and connector ports between adjacent chambers allows for at least partial equalization of the fluid level between adjacent chambers and further mitigates, reduces or prevents short circuiting of the fluid as it passes from chamber to chamber.
• An optional coalescing media may be positioned in or proximate one or more of the interconnecting passages to absorb or coalesce contaminants as they pass therethrough.
• a flotation tank for removing a contaminant from fluid input into the flotation tank, the flotation tank comprising;
• each chamber comprising a sloped weir for inducing a rotational current within the chamber
• skim oil trough spanning each chamber and separated from each chamber by a skimming weir, the skimming weir opposite the sloped weir;
• each chamber in fluid communication with the adjacent chambers via an interconnecting passage positioned substantially towards the bottom of the dividing wall of each chamber and substantially opposite the skim oil trough, the interconnecting passage allowing passage of fluid from a chamber to a backside of the sloped weir of the adjacent chamber;
• a connector port in the dividing wall between two adjacent chambers for providing fluid communication between the two adjacent chambers
• coalescing media positioned in or proximate one or more of the interconnecting passages for absorbing or coalescing contaminants as they pass through the interconnecting passage;
• the connector port is positioned in the base of the dividing wall proximate the skimming weir.
• the interconnecting passage is positioned at one end proximate the base of the sloped weir and at the other end in proximity to a backside of the sloped weir of the adjacent chamber.
• the fluid passage is positioned proximate the base of the sloped weir.
• the fluid passage is a perforated plate in the sloped weir.
• the outlet is positioned proximate the base of the wall of the final chamber.
• each set of adjacent chambers comprises either a connector port or a fluid passage in alternating format allowing for equalization of the fluid level in adjacent chambers while preventing short circuiting of the fluid through the tank to the final chamber.
• the tank further comprises a manifold in fluid communication with each chamber for inputting or withdrawing fluid from the tank.
• the sloped weirs of the tank are aligned with one another in the adjacent chambers.
• the sloped weirs of the tank are offset with one another in at least two of the adjacent chambers.
• an upper edge of the skimming weir comprises at least one notch to promote transfer of the unwanted phase into the skim oil trough.
• the tank further comprises an inlet in fluid communication with each chamber for injecting a gas into the chamber, optionally in the form of micro-bubbles.
• the contaminant comprises hydrocarbon, emulsified oils, or heavy oils.
• the fluid is produced water.
• the coalescing media is a fixed media. In a further embodiment of a flotation tank to that described above, the coalescing media is a non-fixed media.
• the coalescing media is positioned in the interconnecting passage.
• Figure 1 is an isometric view of one illustrative embodiment of a gas flotation tank including five chambers;
• Figure 2 is a top plan view of the gas flotation tank shown in Figure 1;
• Figure 3 is an isometric side view of the gas flotation tank shown in Figure 1;
• Figure 4 is a cross sectional view of the gas flotation tank shown in Figure 1 along the dividing wall between the first and second chamber;
• Figure 5 is a cross sectional view of the gas flotation tank shown in Figure 1 along the third chamber showing the perforated plate allowing for ingress of fluid from second chamber into the third chamber;
• Figure 6 is a cross sectional view of the gas flotation tank shown in Figure 1 between the sloped weir and the skim oil trough showing the connecting ports between the first and second chamber and the third and fourth chamber allowing for fluid communication between these chambers and ingress of fluid from the first chamber into the second chamber and from the third chamber into the fourth chamber;
• Figure 7 is a chart of chamber residence time against cumulative removal efficiency demonstrating increased removal efficiency as the number of sequential chambers increases
• Figure 8 is an isometric view of a further illustrative embodiment of a gas flotation tank including five chambers wherein the sloped weirs of the chambers are arranged at varying positions;
• Figure 9 is an isometric cross sectional view of the gas flotation tank shown in Figure 8 along a divide of the first chamber;
• Figure 10 is an isometric cross sectional view of the gas flotation tank shown in Figure 8 along the dividing wall between the first and the second chamber
• Figure 11 is an isometric cross sectional view of the gas flotation tank shown in Figure 8 along a divide of the second chamber;
• Figure 12 is an isometric cross sectional view of the gas flotation tank shown in Figure 8 along a divide of the third chamber;
• Figure 13 is an isometric cross sectional view of the gas flotation tank shown in Figure 8 along a divide of the fifth chamber;
• Figure 14 is a schematic showing one embodiment of an interconnecting passage including an optional coalescing media.
• Described herein are systems, apparatuses, techniques and embodiments of gas flotation tanks suitable for at least partially removing or capturing contaminants or unwanted phases from a fluid, such as produced water and methods of doing same. It will be appreciated that the methods, systems, apparatuses, techniques and embodiments described herein are for illustrative purposes intended for those skilled in the art and are not meant to be limiting in any way. All reference to embodiments and examples throughout this disclosure should be considered a reference to an illustrative and non-limiting embodiment or an illustrative and non-limiting example.
• a contaminant or unwanted phase includes hydrocarbon or contaminants or phases that at least partially comprise hydrocarbon but are not limited to hydrocarbon and may include other or alternate contaminants that behave in such a manner that a gas flotation tank could be useful in their removal from a fluid.
• FIGS 1 and 3 are isometric views of an embodiment of a flotation tank, such as a gas flotation tank, for removing contaminants, such as unwanted phases, lighter than water hydrocarbon, and/or oil, crude or refined oil, or emulsions, from a fluid, such as produced water.
• a gas flotation tank is shown generally at 10 and is comprised of a tank floor 50 defining the bottom of the tank 10 and a pending tank wall 45 defining the periphery of the tank 10.
• the gas flotation tank 10 is divided into a plurality of sequential chambers for holding and imparting a generally rotational, tumbling or circular current of the produced water in each individual chamber in a generally longitudinal direction of the chamber such that the surface of the fluid moves towards a skim oil trough 15 for capturing contaminant such as hydrocarbon or oil, from the surface of the fluid skimmed off the top of the fluid.
• a series of dividing walls 65 are used to define each chamber.
• the tank 10 shown throughout the figures contains five chambers, it will be appreciated that the tank may have fewer or additional chambers depending on the properties and rheology of produced water to be cleaned, the velocity of the fluid, the rate of purification, etc.
• Each chamber of the tank is connected to the adjacent chamber via an interconnecting passage 75 (shown in Figures 9, 10 and 14) that allows for transfer of the fluid from one chamber to the next.
• An inlet 20, generally positioned towards an upper region of the wall 45 is used to input contaminant containing fluid, such as produced water, into the tank 10 and into the first chamber of the tank 10.
• a sloped weir 40 bisects each of the chambers of the tank 10 for inducing the rotational, tumbling or circular current in each individual chamber.
• the fluid, such as produced water, is input into the first chamber from the inlet 20 in sufficient proximity to the sloped weir 40 to induce a rotational, tumbling or circular current within the first chamber.
• a rotational current in the longitudinal direction of the chamber is induced by the sloped weir 40 that promotes the contaminant, such as lighter than water hydrocarbon, to rise to the surface of the water in the first chamber while the cleaner and thus heavier water is pushed downwards towards the floor 50 of the tank.
• a skimming weir 35 separates the chambers of the tank 10 from a skim oil trough 15 wherein contaminant, such as oil, is collected as it is skimmed over the weir from each of the chambers.
• the skimming weir 35 comprises a one or a plurality of V-shaped notches (not shown) in the upper end of the weir 35 to allow for oil to skim over the weir and into the skim oil trough 15.
• the upper end of the skimming weir may include other shapes of notch to promote skimming of the unwanted phase into the skim oil trough 15 or may simply contain no notches on the upper end of the skimming weir. Once skimmed from the produced water, the oil may be collected using any suitable means.
• the interconnecting passage 75 may collect fluid from substantially the base or a lower region of the sloped weir of a first chamber thereby allowing for increased flow path of the rotating fluid. The interconnecting passage 75 may then output the fluid into the adjacent chamber on a backside of the sloped weir 40 of the adjacent chamber. The input fluid into the adjacent chamber has a rotational current imparted thereon by the sloped weir and the fluid transfer onto the next adjacent chamber may be carried out in a similar manner.
• the interconnecting passage 75 may be formed with the slope weir 45 in combination with a baffle.
• the first and the adjacent chamber may also be fluidly connected via a connecting port 60 situated in the lower region of their dividing wall 65.
• a connecting port 60 By positioning the connecting port 60 in the lower region of the dividing wall, cleaner water is transferred from the first chamber to the second chamber allowing for equalization of the fluid levels in these adjacent chambers. It will be appreciated that the cleaner water is water having a lower contaminant content than that input into the first chamber.
• a rotational current is again induced by a sloped weir 40 to promote the contaminant to rise to the surface of the fluid in the second chamber while the cleaner water is pushed downwards towards the floor 50 of the tank.
• contaminant is skimmed from the second chamber into the skim oil trough 15 over the skimming weir 35 and the fluid in the second chamber is further purified relative the fluid in the first chamber.
• the fluid By positioning the interconnecting passage 75 a suitable distance from the connecting port 60 the fluid must pass through sufficient rotational current to promote the rising of the contaminant to the surface before fluid is communicated from the second to the adjacent third chamber thereby providing fluid having a lower contaminant content to the adjacent third chamber while mitigating short circuiting.
• a fluid passage 70 is used to allow fluid to pass through the sloped weir 40 in the these chambers such as chamber 3.
• fluid is both transferred in the rotational current of the third chamber but can flow through fluid passage 70 in the event that difference in fluid levels between the second and third chamber is substantially different.
• the fluid passage 70 may be in the form of a perforated plate.
• the sloped weir 40 may be positioned at various points in the chambers and it is not essential that the sloped weirs 40 be arranged in a line as shown in the figures 1 to 6.
• the sloped weirs 40 may be offset from one another as shown for example in the non-limited embodiments illustrated in Figures 8 to 13. By adjusting the positioning of the sloped weirs 40 the rate of the current in each chamber may be controlled and adapted as desired or as necessary.
• the sloped weirs induce a rotational current within each chamber.
• the rotational current allows for a lengthened flow path throughout a tank relative a typical tank of the same diameter.
• the lengthened flow path allows for the separation of phases have a specific gravity (SG) approaching that of water such as emulsified oils and viscous fluids such as those used in AEOR polymer flooding.
• SG specific gravity
• the increase in flow path allows for a greater opportunity for bubbles or micro-bubbles to come into contact substantially attach with contaminants in the fluid thereby gradually floating or bringing them to the surface for eventual skimming into the oil trough 15.
• a manifold 25 in fluid communication with the chambers of the tank 10 may be used to fill or empty the tank 10 prior to operation or for maintenance of the tank 10 as needed.
• the outlet 55 may be positioned in the final chamber of the tank 10 opposite the inlet chamber thereby allowing for the passage of the fluid through all of the chambers thus enabling the skimming of the contaminant in each chamber resulting in the greatest reduction of contaminant from the fluid being output from the tank.
• Figures 2, 3, 4, 5 and 6 shows various views of the tank 10 and the fluid passages 70 and alternating connecting ports 60 allowing for fluid communication between adjacent chambers while mitigating short circuiting and allowing for at least partial equalization.
• an interconnecting pipe has been omitted from the tank 10. Such omission also allows for the omission of associated bypass lines and valves thereby reducing the complexity of the design and associated costs and maintenance. Further, scalability of the design is facilitated.
• the avoidance of the interconnecting pipe allows for the increased ability to build tanks capable of larger flows as the design offers a larger scalability. In addition, applications that require similar flows but longer retention times are also made possible.
• situating the fluid passages 70 and/or 85 in the sloped weirs to create the interconnection between various chambers as well as the interconnecting passages 75 may also act to reinforce the tank, whereas an interconnecting pipe offers little to no structural benefit and also requires its own structural supporting incremental to what was required by the tank itself.
• the tank 10 including the alternating setup of connecting ports 60 and fluid passages 70 and 85 is less sensitive to tank filling and draining as the interconnecting ports and fluid passages allow for less restricted flow from chamber to chamber. Alternating between fluid passages and connecting ports helps balance the fluid levels in adjacent chambers during filling and draining. As the fluid levels of adjacent chambers is substantially equalized, a reduction in structural requirements is observed relative to flotation tanks based on an interconnecting pipe setup.
• connector ports 60 and the fluid passages 70 and 85 should alternate from chamber to chamber to ensure that short circuiting is reduced or prevented while still allowing for at least partial equalization of the fluid level between adjacent chambers.
• a longer flow path is established that allows for removal of contaminant from the fluid input before reaching the outlet 55 in the final chamber.
• a significant component of the flow path is horizontal as opposed to vertical in typical designs. This horizontal flow path allows for bubbles or micro-bubbles to attach with contaminants to promote their rise to the surface of the rotational fluid for skimming off.
• Figure 7 demonstrates the relationship that exists that shows that performance is a function of RT vs the number of sequential chambers(separators). Although the tank described herein comprised of five chambers, this suggests that additional chambers should experience an increase in performance. It will be appreciated that in addition to the rotational current induced by the sloped weirs 40, bubbles, optionally in the form of micro-bubbles, may be added to each chamber via an inlet (not shown) to further promote the rising of the contaminant, such as hydrocarbon, to the surface for skimming off into the skim oil trough 15.
• the contaminant such as hydrocarbon
• micro-bubbles may be added toward to base of the dividing wall, optionally in proximity to the connecting ports and act to adhere to the contaminant, such as oil, to promote the rising of the oil to the surface.
• a smaller bubble may be used to lower the rise velocity thereby increasing the opportunity for adherence to the contaminant.
• Micro-bubbles may alternatively or additionally be added at the base of the sloped weir 40.
• the interconnecting passage 75 in an alternative embodiment, may be used to transfer the liquid and also to concentrate the zone of gas/liquid contact of the contaminant to the bubbles or micro-bubbles.
• the bubbles or micro-bubbles may be introduced in the interconnecting passage 75 instead of or in addition to introducing the bubbles or micro-bubbles in the chambers themselves.
• Such a setup of introducing the bubbles or micro-bubbles in a narrow zone allows for an improved probability of contact and attachment with the contaminant in the fluid.
• the introduction of gas may be concentrated to a more confined space, such as the interconnecting passage 75, and then released near the surface as it exits the interconnecting passage 75 where it can effectively be removed from the fluid.
• other technologies work on a principle of dispersing gas in a larger volume, for example within a chamber, as opposed to concentrating the gas into a narrow zone.
• Figure 14 shows an optional embodiment of an interconnecting passage that includes a coalescing media 100 for absorbing or coalescing contaminants as they pass through the interconnecting passage 75.
• the media 100 is suspended above the opening of the interconnecting passage 75, as shown in Fig. 14, thereby allowing the fluid to pass through the media 100 as it moves to the adjacent chamber.
• the media 100 may be positioned at any suitable position within or proximate the interconnecting passage 75 within or partially within the path of flow of the fluid so that fluid passes through the media 100. It will also be appreciated that the coalescing media 100 may be positioned in or proximate one or more or each of the interconnecting passages 75.
• the media 100 may be either a non-fixed media or a fixed media.
• non-fixed media includes“random packing” media, nutshells, etc.
• fixed media includes a corrugated plate, fixed packing, etc.
• the purpose of the media 100 is to increase the droplet or particle size of the contaminant as it passes through the interconnecting passage 75 to improve the buoyancy or floatability of the increased size of droplet or particle thereby promoting the droplet or particle to the surface for skimming.
• the media 100 may be used in conjunction with the gas bubbles/microbubbles, or in place of the gas bubbles.
• the flow rate of the gas bubbles may be increased intermittently, as required or desired, to flush out and clean the coalescing media 100.
• the gas flotation tank shown in Figures 8 to 13 operates in a similar manner to that described above with reference to Figures 1 to 6 with the difference that the sloped weirs 40 are offset from one another in the sequential chambers.
• the velocity profiles of the fluid may be altered to obtain a more desirable separation and/or removal of the unwanted phase or contaminant.
• the present design utilizes an interconnecting passage to transfer the fluid from chamber to chamber and, generally, only use the fluid passages and connecting ports to balance the chambers, whereas a serpentine tank uses perforated plates or openings to transfer fluid from one chamber to the next.
• the present design may use the interconnecting channels, typically comprised of baffles and weir plates, to create the rotational or circular flow pattern in each individual chamber. This is used to hydraulically skim the undesired contaminants and to bring them to the surface faster and giving them more opportunity to reach the surface more often (a result of the water weir plates and the circular pattern they induce).
• the length of the flow path is considered to have an impact on the separation of contaminants including phases
• separation may be achieve through the rotational or circular pattern in a smaller volume as opposed to using the length of the chamber (reusing a smaller volume several times in the circular pattern instead of flowing horizontally once through that volume).
• the result of these can be a reduction of required retention time which in turn dictates the volume (size) of the tank.
• the tank as disclosed requiring l/6th to 1/12th the time (or volume) for identical scenarios.
• the present design allows for a single (shared) skimming means represented by the skimming weir in combination with the skim oil trough, and a single point on the tank (nozzles, piping, and valves reduced) in which the unwanted contaminants may be removed.

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• 2019
  • 2019-01-02 AR ARP190100015A patent/AR114506A1/es active IP Right Grant
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