SUMP PUMP SYSTEM AND METHODS FOR REMOVING SYNTHETIC ESTER-BASED FLUIDS FROM AN EMULSION

Abstract

A polishing filter apparatus employed within a sump pump system for removing mineral oils, natural ester, and synthetic ester-based fluids from an emulsion is provided. The polishing filter apparatus is connected to a sump pump barrier via a polishing filter inlet conduit, Further conduit structures are disposed within the polishing filter apparatus, which lead into a polishing filter cartridge. The polishing filter removes excess synthetic ester-based fluids from a water/oil emulsion fluid flowing therethrough and releases a resultant filtered fluid. The polishing filter cartridge contains a filtration media with a hydrophilic composition for the capture of synthetic ester-based fluid having a surface tension dissimilar to water, and the hydrophilic composition of the media has a surface energy greater than or equal to 35 dynes per centimeter.

Claims

1. A sump pump system for the filtration of synthetic ester-based fluids from an emulsion, comprising: a sump pump barrier having an outlet conduit for the flow of fluid therethrough; a polishing filter apparatus including a polishing filter disposed in a polishing filter barrier, having a polishing filter inlet conduit fluidly connected to the sump pump barrier outlet conduit for the ingress of the fluid into the polishing filter, and a polishing filter outlet conduit for the egress of a filtered fluid; and said polishing filter disposed within the polishing filter barrier of said polishing filter apparatus, and connected to the polishing filter conduit, the polishing filter having a polishing filter cartridge disposed therein, the polishing filter cartridge containing a hydrophilic composition for the removal of synthetic ester-based fluid having a surface tension dissimilar to water, the hydrophilic composition having a surface energy greater than or equal to 35 dynes per centimeter; wherein the fluid flows through the sump pump barrier and into the polishing filter harrier via the sump pump barrier outlet conduit and polishing filter inlet conduit, and is pumped into the polishing filter, and is then filtered via the polishing filter cartridge within the polishing filter housing, and the resultant filtered fluid exiting the polishing filter barrier via the polishing filter barrier outlet conduit contains less than 5 ppm of said synthetic ester-based fluids.

2. The sump pump system of claim 1 wherein the composition contained within the filter cartridge includes polyether sulfone or a glass fiber media.

3. The sump pump system of claim 1 wherein the composition contained within the filter cartridge is a filter media having a surface energy greater than or equal to 45 dynes per centimeter.

4. The sump pump system of claim 1 further including a shutoff valve disposed on one of the pump conduit and polishing filter conduit, the shutoff valve being interactive to open/close the flow of fluids through said pump conduit and polishing filter conduit.

5. The sump pump system of claim 1 further including a polishing filter barrier cover for disposal over the top surface of the polishing filter barrier.

6. The sump pump system of claim 5 further including a shutoff valve access hole carved into the polishing filter barrier cover for providing access to a shutoff valve disposed within the polishing filter barrier and disposed on one of the pump conduit and polishing filter conduit.

7. The sump pump system of claim 5 further including a power cord access hole carved into the polishing filter barrier cover for allowing a power cord to lead into the polishing filter barrier and connect to the pump, supplying the pump with power.

8. The sump pump system of claim 1 further including a pump disposed within the polishing filter apparatus and connected to a pump conduit, the pump conduit further connected to said polishing filter.

9. A method of filtering synthetic ester-based fluids from an emulsion, comprising: providing a sump pump barrier for receiving an emulsified fluid comprising water and synthetic ester-based fluid, wherein surface tension of the synthetic ester-based fluid is dissimilar to surface tension of said water, the sump pump barrier having an outlet conduit for the flow of the emulsified fluid there through; flowing the emulsified fluid through the sump pump barrier outlet conduit into a polishing filter apparatus via a polishing filter inlet conduit; pumping the emulsified fluid through a pump and a connecting polishing filter inlet conduit, the polishing filter inlet conduit further leading into a polishing filter, all of which are disposed within the polishing filter apparatus; filtering said synthetic ester-based fluid from the emulsified fluid flowing through the polishing filter inlet conduit into the polishing filter via a polishing filter cartridge disposed within said polishing filter of the polishing filter apparatus, the polishing filter cartridge containing a hydrophilic composition having a surface energy greater than or equal to 35 dynes per centimeter for the capture of the synthetic-ester based fluid resulting in a filtered fluid via the filtration of the emulsified fluid by the polishing filter cartridge; and egressing the filtered fluid from the polishing filter apparatus via a polishing filter outlet conduit.

10. The method of claim 9 wherein the composition contained within the filter cartridge hydrophilic composition includes polyether sulfone or a glass fiber media.

11. The method of claim 9 wherein the surface energy of the hydrophilic composition contained within the filter cartridge is greater than or equal to 45 dynes per centimeter.

12. A polishing filter apparatus for the filtration of synthetic ester-based fluids from an emulsion, comprising: a polishing filter, a polishing filter barrier, and an inlet conduit for receiving a flow of a fluid, said fluid comprising a synthetic ester based fluid and water emulsion, wherein the synthetic ester based fluid has a surface tension dissimilar to that of the water, and an outlet conduit for the egress of a resultant filtered fluid; a pump disposed within the polishing filter barrier for pumping the fluid through a pump conduit; and said polishing filter disposed within the polishing filter apparatus and fluidly connected to the polishing filter inlet conduit, the polishing filter having a polishing filter housing and a polishing filter cartridge disposed therein, the polishing filter further being fluidly connected to a polishing filter outlet conduit; wherein the fluid pumped into the polishing filter is filtered of said synthetic ester-based fluids via the polishing filter cartridge, wherein resultant filtered fluid exits the polishing filter apparatus via the polishing filter outlet conduit.

13. The polishing filter apparatus of claim 12 further including a polishing filter conduit connected to the pump conduit, and a shutoff valve disposed on one of the pump conduit and polishing filter conduit.

14. The polishing filter apparatus of claim 12 further including a filter housing conduit stub for connecting the polishing filter to the polishing filter barrier outlet conduit.

15. The polishing filter apparatus of claim 12 further including a power cord leading into the polishing filter barrier and connecting to the pump for supplying the pump with power.

16. The polishing filter apparatus of claim 12 further including a polishing filter harrier cover having a shutoff valve access hole for easy accessibility to a shutoff valve disposed on one of the pump conduit and polishing filter conduit.

17. The polishing filter apparatus of claim 12 further including a polishing filter barrier cover having a power cord access hole for allowing a power cord to lead into the polishing filter barrier and connect to the pump for supplying the pump with power.

18. The polishing filter apparatus of claim 12 wherein the polishing filter cartridge contains a hydrophilic filtration media composition capable of removing synthetic ester-based fluids from the fluid, such that a surface energy of the hydrophilic composition is greater than or equal to 35 dynes per centimeter.

19. The polishing filter apparatus of claim 18 wherein the polishing filter cartridge filtration media composition is polyether sulfone or glass fiber.

20. The polishing filter apparatus of claim 18 wherein the polishing filter cartridge filtration media composition has a surface energy greater than or equal to 45 dynes per centimeter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The features of the invention believed to be novel and the elements characteristic of the invention are set forth with particularity in the appended claims. The figures are for illustration purposes only and are not drawn to scale. The invention itself, however, both as to organization and method of operation, may best be understood by reference to the detailed description which follows taken in conjunction with the accompanying drawings in which:

[0028] FIG. 1 is a table of prior art laboratory results showing occasional inconsistent measurements of over 20 parts per million of synthetic ester-based fluid in a tested post-filtered water, the tested water being filtered by the prior art, sump pump barrier described herein.

[0029] FIG. 2 is a perspective, partially exploded view of a sump pump system of the present invention with the polishing filter barrier separated from the polishing filter housing;

[0030] FIG. 3 is a top down, partially cross-sectional view of the sump pump system of FIG. 2;

[0031] FIG. 4 is a side cross-sectional view of the sump pump system of FIG. 2;

[0032] FIG. 5 is a top down view of the sump pump system of FIG. 2;

[0033] FIG. 6 is a side elevational view of the sump pump system of FIG. 2;

[0034] FIG. 7 is a table of laboratory results showing a consistent measurement of 5 parts per million or less of synthetic ester-based fluid in a tested post-filtered water; the tested water being filtered with the sump pump system of the present invention;

[0035] FIG. 8 is a table of surface energies for various materials;

[0036] FIG. 9 is a table of surface tensions for various liquids; and

[0037] FIG. 10 is a table with test data samples demonstrating the efficiency of the current invention in the filtration of oils and synthetic esters from an emulsion at consistent measurements below 2 ppm.

DESCRIPTION OF THE EMBODIMENT(S)

[0038] In describing the embodiment(s) of the present invention, reference will be made herein to FIGS. 1-10 of the drawings in which like numerals refer to like features of the invention.

[0039] The present invention explores the relationship between surface energy, surface tension, and filtration media porosity in order to create a sump pump barrier system capable of filtering any type of oil (e.g. mineral oil, synthetic ester, natural ester, etc.) from a liquid emulsion. Surface energy is essentially the measurement of disruption of intermolecular forces on a particular surface, ranging in measurements from high (e.g., copper) to low (e.g., Teflon or Polytetrafluoroethylene). Generally, the higher the measured surface energy, the more hydrophilic the surface or substrate, while the lower the measured surface energy, the more hydrophobic the surface or substrate is. Exemplary surface energy measurements are shown in FIG. 8. Surface tension relates to the measured tension of the surface “film” or “layer” of a liquid caused by the inter-molecular force of the liquid particles and their tendency to shrink into a minimum surface area. FIG. 9 provides exemplary surface tension measurements of various liquids with water having a notably high surface tension measurement when compared to the majority of the other liquids shown.

[0040] The relationship between surface tension and surface energy is important in establishing the levels of attraction/repulsion between the media and the fluid. The higher the measured surface tension, the stronger the intermolecular attractions (and amount of energy needed to separate said attractions). Generally, a fluid with a higher surface tension is less likely to wet a filtration media with a low surface energy. Thus, the surface energy of a filtration media is a necessary measurement in determining the retention factor against fluids with a high surface tension. At adequately small dimensions of the filter media (porosity), this force can be utilized to retain desired fluids by appropriate selection of media. Therefore, matching high surface tension fluids to high surface energy filter media will effect the desired separation of oil from water.

[0041] The development of the synthetic ester emulsion filters began with an observation made during an attempted filtration of what was assumed to be particulate impurities in effluent from a barrier test. The presumed particulate matter was theorized to be high molecular weight fractions (and thus high boiling) of the surfactant (Span 80) used in the graphene/graphite polymer composite disclosed in the '735 Patent. Upon filtration of the visible particulates, an unexpected result was observed that particulates were absent. Instead, the presence of oil was identified and confirmed, as shown by the prior art lab results of FIG. 1. Further investigation led to the realization that the oil present was an ester transformer fluid (Midel® oil). The Midel® oil, due to its combined characteristics of relatively polar nature and its density of nearly 1 g/mL, forms a very stable emulsion with water especially when passed through a high rpm sump pump. Essentially, the dissimilarity of the surface tension of synthetic ester/Midel® oil (comparative to water, which is approximately 73 dynes/cm; see FIG. 9) to water forms a filtration media capable of retaining oil while simultaneously allowing water to bypass in a manner that meets or exceeds EPA regulations. Through further experimentation, it was found that a hydrophilic media composition was required to achieve this.

[0042] Since the material being held back was oil and not particulates, it is more probable that the mode of retention is not exclusion by physical size but rather by some other physical or chemical parameter. It was determined that the filter used was of a certain polymer membrane (polyether sulfone), which is noted for its very hydrophilic nature and hence high flow rates in aqueous systems. It was then determined that the polyether sulfone membrane was able to retain the ester oil (Midel® oil) in any concentration, whether or not it was emulsified, while allowing water to flow. It, was further determined that other oils including standard transformer oils were similarly retained by this type of filter. Thus, the mode of separation was predicated on surface tension of the components relative to the surface energy of the membrane. The polyether sulfone membrane is very hydrophilic, having a relatively high surface energy—near that of water. This hydrophilic nature is what makes it very suitable for aqueous media. It is able to have relatively high flow rates compared to hydrophobic media at equivalent porosities.

[0043] Typically, challenges are presented where it is necessary to remove trace amounts of water from petroleum feedstock. Filter media that allows oil to pass but retains water is desirable; however, in such industries the opposite perspective has not been readily addressed in the same fashion—removing oil from a water feed. Moreover, the concept of the present invention of utilizing surface energy differentiation to drive separation of oil from water utilizing a hydrophilic filter media is unique to the art.

[0044] It has been determined that optimization of flow rate while maintaining oil retention is a necessary limitation. A limit was reached using polyether sulfone membrane filters wherein the available porosity of membranes is not able to economically achieve the flows required. Consequently, a new hydrophilic type of media was introduced into the system and tested. The new media, glass fiber, was very hydrophilic. It was able to perform as well as the polyether sulfone membrane in terms of oil retention and was more economically viable. It was also available in a wider range of porosities. Through various trials it was determined that a cartridge containing media at a porosity of between 0.2-20 μm was suitable for the pressures and flows of the barrier system that the filter supports.

[0045] Filtration media has become highly specialized for various purposes. Among the critical parameters in filtration is the relative hydrophilicity, or conversely hydrophobicity, of the media. Filters with highly hydrophilic media have been developed specifically to allow for greater flow (throughput) of aqueous solution at a given porosity. The physical parameter of surface energy, which is a property inherent to any given material, determines the relative hydrophilicity of a given media. Exemplary surface energy measurements of various compositions are provided in FIG. 8, and the relative surface tensions of various liquids are shown in FIG. 9. Materials with relatively high surface energy (e.g., copper) allow for greater water flow as water itself has a high surface tension (relative to most liquids; see FIG. 9). Materials of very low surface energy (e.g., Polytetrafluoroethylene; more commonly known as Teflon) will allow high flow of many organic liquids but will greatly resist the flow of aqueous solutions without being put through a process known as pre-wetting. Such materials (hydrophobic, low surface energy) are also susceptible to filter blinding (i.e., having the filtering fluid being unable to interact with the filter media) via de-wetting.

[0046] The present invention demonstrates how the effect of surface energy (in conjunction with appropriate porosity) can be used in a filtration system to separate effectively oils (typically having a very low surface tension) from water. The interplay between surface energy and porosity is selected and utilized to determine the ability of a filter to perform this task. Empirical evidence has demonstrated that the higher the surface energy of the filter media, the larger the pores can be and still successfully retain oil. Conversely, lower surface energy materials require smaller pore size in order to be effective. At a point, as the surface energy becomes lower, a filter may no longer be able to hold back the oil at all. Continuing the trend of decreasing surface energy relative to the fluid being filtered, it will Be possible to have the low surface tension liquid pass while retaining the water from such a mixture (these are considered hydrophobic filters).

[0047] A sump pump system 100 comprising a sump pump barrier 10 and a polishing filter apparatus 30, inclusive of a polishing filter barrier 20 with a polishing filter 32 disposed therein is provided. Sump pump barrier 10, as previously described above, comprises an outlet conduit 12 and a connecting fitting 14 for securing the connection between sump pump barrier 10 and polishing filter 32, which upon assembly is enclosed in polishing filter barrier 20, and forming polishing filter apparatus 30, as shown in FIGS. 2-6.

[0048] As depicted in FIG. 3, polishing filter inlet conduit 22 leads at one end into the polishing filter 32 and connects to the sump pump outlet conduit 12 via the connecting fitting 14 at the other end. Polishing filter barrier 20 is in mechanical communication with the polishing filter inlet conduit 22, an outlet conduit 24, and a barrier cover 26 for disposal over the top surface of the polishing filter barrier 20. Disposed within the polishing filter barrier 20 is a pump 40, from which leads a pump conduit 42 therefrom and connects to a polishing filter conduit 31 via a union fitting 44, or by any other acceptable fluid-tight connections. A shutoff valve 46 may be disposed anywhere along the polishing filter conduit 31 or pump conduit 42, the shutoff valve being interactive to open/close the flow of fluids through said conduits 31, 42. Shutoff valve 42 may be accessible to an end user through the polishing barrier cover 26, such as via a shutoff valve access hole 27 carved into the barrier cover 26. An optional power cord 28 leads from the outside of the polishing filter barrier 20 into the barrier via a power cord access hole 29 accessible through the polishing barrier cover 26, and connects to the pump 40 to supply power.

[0049] Polishing filter conduit 31 leads into a polishing filter 30, which is also disposed within the polishing filter barrier 20. The polishing filter apparatus 30 comprises the polishing filter 32 having a polishing filter cartridge 34 disposed therein. The polishing filter cartridge 34 may contain a media comprising poly ether sulfone, glass fiber, or any other hydrophilic media capable of retaining/capturing/removing synthetic ester-based fluids. Alternatively, in at least one preferred embodiment, any filter media having a surface energy greater than or equal to 30 mJ/square meter may be used within the polishing filter cartridge 34. In another preferred embodiment, the filter media surface energy is greater than or equal to 45 mJ/square meter. A filter housing support 36 is disposed on the top surface of the polishing filter apparatus 30 from which the polishing filter conduit 31 is connected, and the polishing filter 32 is suspended on within the polishing filter barrier 20. A filter housing conduit stub 38 extends from the bottom edge of the filter housing 32, which leads into the outlet conduit 24. Conduit stub 38 is further secured to the outlet conduit 24 via a conduit stub fitting 39.

[0050] When a water and synthetic ester emulsion is pumped through the initial sump pump barrier 10, the majority of the synthetic ester is filtered out from the emulsion and absorbed by the filter media disposed within the sump pump barrier. However, given the problems with proper filtration of synthetic ester-based fluids as described above, some of this synthetic ester remains emulsified and egresses from the sump pump barrier 10 with the flowing water. This egressing water (still containing trace amounts of synthetic ester) will immediately enter the polishing filter barrier 20 of the present, invention via the connection between the sump pump outlet conduit 12 and polishing filter barrier inlet conduit 22, and will begin to build up within the polishing filter barrier 20. The egressed water is then pumped upwards via the pump 40 through the pump piping 42, further through the polishing filter conduit 31, and into the polishing filter 32. The egressed water is then filtered of any remaining amounts of synthetic ester, to which the now purified water exits the polishing filter barrier 20 through the outlet conduit 24. Any overflow of emulsified fluids within the polishing filter barrier 20 may be addressed by activating the shutoff valve 46 to halt further flow of fluid.

[0051] The United States Environmental Protection Agency (“EPA”) requires the discharge of water containing oil (including natural ester-based and synthetic ester-based fluids) from power plants to be below 15 parts per million (“ppm”). Many United States territories have more stringent requirements, and Canadian, European, and Australasian regions can have even stricter requirements. The sump pump system 100 of the present invention has proven to be consistently successful in achieving measured values of 5 ppm or less across fourteen separate laboratory tests as shown in FIG. 7, and more recently to maintain consistent measured values of less than 2 ppm as exemplified in the laboratory test data shown in FIG. 10—far below the required threshold of 15 ppm as set by the EPA.

[0052] FIGS. 7 and 10 demonstrate that the Pump-Thru-Barrier (“PTB”) has been tested with synthetic ester fluid for use as an effective oil containment method. Synthetic ester fluid has the appearance of oil but is a different composition from regular mineral oil and other hydrocarbon oils and fuels. Synthetic ester has become a better alternative for certain electric utility companies due to a much higher flash point relative to a reduced potential of explosions and fire.

[0053] The method of the present invention was developed for preventing synthetic ester discharge from containment areas in the event of a large oil spill from a failed transformer or from tanks and equipment filled with synthetic ester. In these applications, products for passive water drainage and absorption/solidification of synthetic ester achieve stoppage of synthetic ester to a point lower than 5 ppm in a water/rain discharge. Even straight (i.e., non-emulsified) synthetic ester oil spills may be stopped in such scenarios. The PTB on its own can stop all flow after the synthetic ester is absorbed in the media as described in the '735 Patent previously referenced herein, but cannot meet the discharge levels required without further treatment, such as the introduction and implementation of a polishing filter of the present invention.

[0054] The present invention thus uses the Solidification Products' PTB in environments subject to rain events where a synthetic ester spill could occur, and further utilizes a pump to carry the water/synthetic ester emulsion to the PTB. In these conditions, the emulsion is blended into a milky solution at up to 30 gpm, which then filters through the PTB media canister. The discharge water from this method had been laboratory tested through multiple tests and the measured ppm of synthetic ester in the water was deemed unsatisfactory, as demonstrated in FIG. 1. Samples taken directly from the discharge held ppm levels up to 65 ppm, depending on what stage of testing the samples were taken.

[0055] It was determined the polishing filter 32 of the present invention was required to achieve consistently low ppm levels (below 5 ppm). The discharge water from the PTB drains into the polishing filter barrier 20 where the pump 40 is disposed. The pump 40 includes a diaphragm switch, which for example is capable of turning on the pump at a 4″-6″ fluid level and shutting off the pump at a 1″-2″ fluid level. The water is pumped from within the polishing filter barrier 20 into the polishing filter 32. Here, the water is then restricted to an optimum flow rate, such as 12 gpm, and pumped into the polishing filter. The polishing filter 32 for the new filter cartridge 34 and corresponding media was designed and built to incorporate everything within the polishing filter apparatus, which also contains the pump, conduit system, and preferably a ball valve to pump directly into the polishing filter.

[0056] It has been determined that the matching of surface energy of the filter media to the surface tension of the fluid being filtered with the current system is such that it is able to force a phase from a highly emulsified oil/water mixture and allow the water to pass while retaining the oil. Throughout this filtration process, the emulsion remains stable due to the relative density and polarity of the synthetic ester oil as compared to water.

[0057] Thus, the present invention provides one or more of the following advantages: 1) a sump pump system for the filtration of synthetic ester-based fluid from an emulsion; 2) a method for removing synthetic ester-based fluid from an emulsion; 3) an apparatus for the effective removal of synthetic ester-based fluid from an emulsion; and 4) a new permutation/formulation of media effective against all oils, including mineral, natural, and/or synthetic esters.

[0058] While the present invention has been particularly described, in conjunction with one or more specific embodiments, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. It is therefore contemplated that the appended claims will embrace any such alternatives, modifications and variations as falling within the true scope and spirit of the present invention.