Patent Application
20180186098
The present invention is related to a composite article useful for removing contaminants from a liquid fluid; and to a process for manufacturing the composite article.
Heretofore, various pipe structures and methods have been used for removing contaminants from liquid fluids flowing through the interior space of the pipe structures. Typically, the known methods for removing contaminants are based on coatings applied to metal pipe substrates (e.g., steel, aluminum, and the like). For example,
U.S. Pat. Nos. 8,726,989 and 8,746,335 disclose methods for removing contaminants from wastewater during a hydraulic fracturing process utilizing a pipe coating on the inner surface of a pipe to capture contaminants from the hydraulic fracturing operation. The use of a coating applied to the inner surface of a pipe to capture contaminants has its disadvantages including, among others, the following disadvantages: (1) an extra layer is required for the overall structure of the pipe; (2) the added extra coating layer reduces the inner diameter of the pipe, thus constricting the space that fluid can flow inside the pipe; and (3) an additional processing step is required for applying the coating layer to the pipe when the pipe is being manufacturing. Furthermore, the processes of the above patents do not provide for a contaminant removal mechanism which is incorporated directly into a pipe structure, that is, the pipe structure does not include an integral contaminant removal layer bonded to the pipe structure.
U.S. Pat. No. 4,171,238 discloses a method of making reinforced plastic composite structures. The above patent describes the incorporation of micron-size particulate, such as cement particles, for the purpose of reducing the amount of wear that occurs inside of a pipe, that is, the above patent is concerned with increasing resistance to acids or other corrosive materials. The patent further discloses an attempt to make a particulate and resin bonded together in a single matrix wherein the particulate is suspended inside the resin such as a polyester resin. The above known process disclosed in U.S. Pat. No. 4,171,238 suffers from the disadvantage of requiring the distribution of particles throughout all fiber reinforced regions and the inability to preferentially place a predetermined amount of particles in a predetermined fiber reinforced region of the fiber reinforced composite to maximize functionalization while minimizing cost.
In U.S. Pat. No. 6,620,475, a structure for a wound fiber reinforced plastic tubing and method for making the tubing is described. The above patent describes the formation and manufacture of a fiber-reinforced composite pipe through a filament winding process using an inner liner and one or more layers of fiber reinforcing material. The above known process disclosed in U.S. Pat. No. 6,620,475 does not utilize the inner liner of the composite material as a multifunctional material that is able to capture unwanted contaminants from a flowing fluid coming in direct contact with the surface of the inner liner.
Embodiments may be realized by providing a fiber-reinforced composite article useful for contaminant removal. The fiber-reinforced composite includes at least one single layer of a fiber-reinforced composite comprising several sections, areas or regions making up the single layer of the composite. For example, the composite may include the following regions in the at least one single layer: (a) at least one first polymer fiber-free region containing material adapted for removing contaminants, said contaminant removal material integrated into the first polymer fiber-free region; said first polymer fiber-free region including an inner surface and an outer surface; (b) at least one second polymer fiber-rich region containing fiber reinforcement material; said second polymer fiber-rich region including an inner surface and an outer surface; and (c) at least one third polymer boundary region containing a portion of the first polymer fiber-free region and a portion of the second polymer fiber-rich region; wherein the outer surface of the first polymer fiber-free region is integrally bonded to the inner surface of the second polymer fiber-rich region forming the at least one third polymer boundary region disposed between the first polymer fiber-free region and the second polymer fiber-rich region; wherein the third polymer boundary region further comprises a contiguous boundary of a non-delineated width between the first polymer fiber-free region and the second polymer fiber-rich region; and wherein the first polymer fiber-free region is integrally attached to the second polymer fiber-rich region such that the first polymer fiber-free region and second polymer fiber-rich region are infused together forming the at least one third polymer boundary region.
Another embodiment of the present invention is directed to a process for making the above composite article. Other embodiments of the present invention include an apparatus and process of manufacturing a fiber-reinforced composite article. Still another embodiment of the present invention is directed to a process for removing contaminants using the above composite article, particularly when the composite article is a conduit such as a pipe.
For the purpose of illustrating the present invention, the drawings show a form of the present invention which is presently preferred. However, it should be understood that the present invention is not limited to the precise arrangements and instrumentation shown in the drawings. In the drawings, like elements are referenced with like numerals. Therefore, the following drawings illustrate non-limiting embodiments of the present invention wherein:
The present invention solves several problems of the known processes. For example, the process of the present invention provides a contaminant removal mechanism which is incorporated directly into an article, such as a pipe, reducing the time required to fabricate a composite structure or part. In addition, the composite fabrication process allows for the production of an article of varying sizes such as a pipe with inner diameters of less than one inch. Furthermore, the present invention demonstrates that functional additives can be preferentially placed in a fiber reinforced composite to maximize functionalization while minimizing cost. And, the composite structure of the present invention utilizes one or more of the composite's structural parts, such as the inner liner of a composite pipe material, as a multifunctional material that is able to capture unwanted contaminants from a flowing fluid coming in direct contact with the composite surface.
In one embodiment, the present invention includes incorporating a contaminant-capturing filler into a composite material such as the incorporation of the filler results in a multi-functional composite material. The multi-functional composite material provides all of the benefits of a composite article with the additional benefit of being able to capture contaminants. For example, in one preferred embodiment, the present invention is directed to a method of manufacturing a fiber-reinforced composite article for radionuclide removal. The fiber-reinforced composite material utilizes a contaminant removal process embedded within the composite material very near the surface of the formed composite article which is in contact with the contaminant. The unique method of manufacture of the present invention can be utilized in a wide variety of different applications and processes for making composite articles, including for example infusion, pultrusion, filament winding, and other similar processes. In one specific embodiment, the manufacturing method of the present invention can be used for manufacturing a multi-layer composite pipe article of a predetermined number of layers and of a predetermined inner diameter.
For example, in another preferred embodiment, the present invention includes the use of a filament winding method to manufacture a composite pipe structure that can be used in a piping application. However, the scope of fabrication of the present invention is not limited to only a filament winding process but may include any composite fabrication method and/or polymer matrix where composite articles can be made. However, the present invention manufacturing process is more complicated that simply using a filament winding operation to fabricate a pipe. And, the present invention described herein includes a multifunctional composite material.
Terms used herein include the following:
“Fiber-free region” herein means a region of cured polymer matrix that that has no amount of fiber reinforcement material in the polymer matrix.
“Fiber-rich region” or “fiber-reinforced region” herein means a region of cured polymer matrix that contains an amount of fiber reinforcement material in the polymer matrix.
“Contiguous boundary of a non-delineated width” herein means a qualitative interfacial region between the fiber-free region and fiber-rich region, wherein the interfacial region is of a non-measurable width and is chemically bonding the fiber-rich region and fiber-free region forming a homogeneous integral boundary region generally of a cross-section where the fiber-free region and fiber-rich region are integrally in contact with one another via the boundary region.
“Radionuclide” herein means an isotope with an unstable nucleus, characterized by excess energy available to be imparted either to a newly created radiation particle within the nucleus or via internal conversion.
“Radionuclide removal” herein means the transfer of the unstable nucleus described above from an undesired location to a desired location.
The present invention incorporates (imbeds), for example, a radionuclide removal mechanism (e.g., in the form of BaSO4 crystals or particles) into a fiber-reinforced composite pipe manufacturing method through the use of a two-step manufacturing process (gel layer production and then filament winding) resulting in a light-weight fiber-reinforced composite pipe product adapted for contaminant capture without the need for a separate coating layer. Furthermore, the pipe with the contaminant removing layer is manufactured substantially simultaneously; and the diameter of the pipe is not limited to a specific diameter, i.e., the pipe can be made to have a wide or a very narrow diameter. The capability to adjust a pipe's diameter is advantageous because a narrow diameter pipe can be used instead of a pipe with a thick metal protective layer even for high pressure situations (for example hydraulic fracturing). By having radium capture occur on the composite pipe itself, i.e., downwell rather than above ground, this can eliminate or lessen the need for an above-the-ground treatment of the water and other fluids coming out of the well.
With reference to
The fiber-reinforced composite 10, such as pipe member 10, is useful for removing contaminants present in a liquid fluid when the liquid fluid flows through the interior space 11 of the pipe member 10 and the fluid comes into contact with the first polymer fiber-free region 12 of the composite. The mechanism for removing contaminants is built into the composite structure which includes the first polymer fiber-free region 12 containing a material adapted for removing contaminants such as particles 16. The contaminant-removing particles 16 are integrated into the first polymer fiber-free region 12; and are integrally embedded in the polymer of the first polymer fiber-free region 12. The first polymer fiber-free region 12 preferably contains only particulate material 16 and no fibers 17 are contained in the fiber-free region 12.
The second polymer fiber-rich region 13 contains fiber reinforcement material 17 such continuous or discontinuous fibers 17. The fibers 17 are integrated into the second polymer fiber-rich region 13; and are integrally embedded in the polymer of the second polymer fiber-rich region 13. The second polymer fiber-rich region 13 preferably contains only fibers 17 and no particles 16 are contained in the fiber-rich region 13.
As aforementioned, upon bonding the outer surface of the first polymer fiber-free region and the inner surface of the second polymer fiber-rich region, a third polymer boundary region 14 is formed. The outer surface of the first polymer fiber-free region 12 is integrally bonded to the inner surface of the second polymer fiber-rich region 13 forming the third polymer boundary region 14 disposed between the first polymer fiber-free region 12 and the second polymer fiber-rich region 13 as shown in
In
In
With reference to
Another embodiment of a composite pipe structure is shown in
With reference to
Additionally, a curing agent is used in the first polymer fiber-free gel layer 41 to react with the first polymer to form the cross-linked first polymer network. The curing agent (also known as a hardener or crosslinking agent) may include for example polyamides, polyamidoamines, phenols, amino-formaldehydes, carboxylic acid functional polyesters, anhydrides, polysulfides, polymercaptans, and mixtures thereof.
The first polymer fiber-free gel layer 41 also includes particulate material for removing contaminants such as barium sulfate particulate 47 dispersed in the first polymer fiber-free gel layer 41. Other particles 47 that can be dispersed and embedded in the first polymer fiber-free gel layer 41 may include for example barium sulfate particles with a diameter of from about 1 μm to about 5 μm.
The amount of particles 47 present in the first polymer fiber-free gel layer 41 may be generally from about 10% by weight to about 95% by weight in one embodiment, from about 20% by weight to about 90% by weight in another embodiment, and from about 30% by weight to about 85% by weight in still another embodiment.
In one preferred embodiment, the first polymer fiber-free gel layer 41 may be include a bisphenol-A-based epoxy resin as the first polymer, an amine curing agent, and barium sulfate particulate.
One of the beneficial properties of the gel layer 41 is the capability of the gel layer 41 to remove contaminants such as radionuclide from a liquid fluid coming into contact with the gel layer 41. “Fiber-free” with reference to the amount of fibers 48 present in the gel layer 41 means there is less than 15% by weight amount of fibers in the gel layer 41 and preferably zero.
The first system or formulation for making the first polymer fiber-free gel layer 41, is designed to have an initial viscosity of at least 20,000 mPa-s to prevent sagging and dripping when the gel layer 41 is applied to the mandrel 45; and the formulation is designed to have a gel time of approximately (˜) 20 minutes. For example the gel layer 41 may have an initial viscosity of generally from about 10,000 mPa-s to about 40,000 mPa-s in one embodiment, from about 15,000 mPa-s to about 30,000 mPa-s in another embodiment, and from about 18,500 mPa-s to about 25,000 mPa-s in still another embodiment. For example the gel layer 41 may have a gel time of generally from about
5 minutes (min) to about 45 min in one embodiment, from about 10 min to about 30 min in another embodiment, and from about 15 min to about 25 min in still another embodiment.
The thickness of the gel layer 41 of the composite article structure 40 can be generally from about 0.25 millimeters (mm) to about 5 mm in one embodiment, from about 0.5 mm to about 3 mm in another embodiment, and from about 1 mm to about 2 mm in still another embodiment. A gel layer 41 that is too thin (i.e., less than about 0.25 mm) may not provide enough coverage to the inside of a pipe member and will result in an underperforming part with less contaminant capture than desired. A gel layer 41 that is too thick (i.e., greater than about 0.5 mm) can result in adverse processing issues such as gel-layer dripping and waste.
In the embodiment shown in
As shown in
The second polymer fiber-rich composite layer 42 of the composite article 40, shown in
Additionally, a curing agent is used in the second polymer fiber-rich composite layer 42 to react with the second polymer to form the cross-linked second polymer network.
The second polymer fiber-rich composite layer 42 also includes a fiber-reinforcement which can be for example continuous fiber or discontinuous fiber. The fibers 48 in the polymer matrix of the composite layer 42 may be of different origins, including but not limited to, carbon fibers (including for example pitch based and polyacrylonitrile based), glass fibers (including for example e-glass, s-glass, and the like), aramid fibers, natural fibers, and mixtures thereof. The fibers can be applied in any direction in a three-dimensional coordinate frame that is consistent with theory dictating a functioning laminate structure.
The amount of fibers 48 present in the second polymer fiber-rich composite layer 42 may be generally from about 50% by weight to about 85% by weight in one embodiment, from about 60% by weight to about 80% by weight in another embodiment, and from about 65% by weight to about 70% by weight in still another embodiment.
The thermosetting or thermoplastic resin used as the second polymer matrix of the composite layer 42 preferably has a suitable viscosity to achieve homogenous fiber bundle impregnation during a specified residence time dictated by the particular individual process used (for example, in a filament winding process, the residence time is the time the fiber bundle spends in the impregnation bath). For example, in a preferred embodiment, the composite layer 42 may be made of continuous fiber rovings and a thermosetting resin matrix such as an epoxy resin. Alternatively, the composite layer 42 may comprise a continuous fiber roving and a thermoplastic matrix. The thermoplastic matrix can be for example polypropylene, polysulfone, polyether ether ketone and the like; and mixtures thereof.
One of the beneficial properties of the composite layer 42 is that the layer 42 is free of the radionuclide capturing particle material 47 and exhibits a homogenous laminate structure (i.e., the composite layer 42 is free of defects, for example less than about 5% by weight [defects]). “Free of particles” with reference to the amount of particles 47 in the composite layer 42 means there is less than 10% by weight amount of particles in the composite layer 42 and preferably zero.
In one embodiment, the composite layer 42 of the composite article structure 40 of the present invention is disposed on the outer surface of the veil layer 43. As shown in
The thickness of the composite layer 42 of the composite article structure 40 is not limited to a predetermined thickness. However, the thickness of the composite layer 42 can be generally from about 0.25 mm to about 100 mm in one embodiment, from about
1 mm to about 60 mm in another embodiment, and from about 5 mm to about 40 in still another embodiment.
The veil layer 43 of the composite article 40, shown in
One of the beneficial properties of the veil layer 43 is to provide a separating layer such that a more defined boundary can be establish between the first polymer fiber-free region containing a radionuclide removal mechanism and the second polymer fiber-rich region containing fiber reinforcement which provides mechanical strength to article 40.
In one embodiment, the veil layer 43 of the composite article structure 40 of the present invention is laid in between the composite layer 42 and the gel layer 41. As shown in
The thickness of the veil layer 43 of the composite article structure 10 can be generally from about 8 μm to about 100 μm in one embodiment, from about 10 μm to about 75 μm in another embodiment, and from about 15 μm to about 50 μm in still another embodiment.
The release film layer 44 of the composite article 40, shown in
In one embodiment, the release film layer 44 of the composite article structure 40 of the present invention is disposed in between the gel layer 41 and the inner mandrel 45. As shown in
The thickness of the release film layer 44 of the composite article structure 40 can be generally from about 0.01 mm to about 2 mm in one embodiment, from about 0.05 mm to about 1 mm in another embodiment, and from about 0.1 mm to about 0.5 mm in still another embodiment.
The inner mandrel 45, shown in
As shown in
The structure 40 of
The overall diameter of the pipe structure 40 with the multi-layer construction as shown in
The composite product or article, such as a pipe, prepared by the process of the present invention exhibits unexpected and unique properties. In one embodiment for example, the overall fabricated composite article can weigh less than a similar conventional metal part performing the same function. For example, the composite of the present invention can weigh less than a metal counterpart part generally less than about 5% to about 75% in one embodiment, less than about 10% to about 60% in another embodiment, and less than about 15% to about 50% in still another embodiment.
Another broad scope of the present invention includes a process for manufacturing a fiber-reinforced composite article for radionuclide removal. The process includes manufacturing a composite article by bonding at least two polymer layers to form a single composite article containing at least one first polymer fiber-free region, at least a second polymer fiber-rich region, and a third boundary region disposed between (separating) the first polymer fiber-free region and the second polymer fiber-rich region. The system, composition, or formulation, includes components to manufacture: (a) a first polymer fiber-free region containing contaminant-removing particles such as radionuclide removal particles; and components to manufacture: (b) a second polymer fiber-rich region containing fiber reinforcement material.
The fiber-free polymer region containing a contaminant-capturing material such as radionuclide-removal particles comprises the gel layer of the composite. The composition used to form the gel layer of the composite includes for example, the following compounds or components: (i) an epoxy resin such as a novolac type epoxy resin, (ii) a curing agent such as an amine curing agent for curing the epoxy resin, and (iii) a contaminant-capturing particulate material such as BaSO4. The above gel layer composition can also include (iv) a dispersing aid (e.g., BYK-940) for homogenously dispersing the above components throughout the fiber-free polymer region, particularly for dispersing the above particulate material into the fiber-free polymer region.
In one embodiment, the first formulation is applied as a gel layer and is designed to have a high (e.g., >than about 20,000 mPa-s) initial viscosity, to prevent sagging and dripping, and to have a fast gel time (e.g., <1 hour at 25° C.). For example, the viscosity of the first formulation to form the gel layer can generally be from about 20,000 mPa-s to about 80,000 mPa-s in one embodiment, from about 30,000 mPa-s to about 60,000 mPa-s in another embodiment, and from about 40,000 mPa-s to about 55,000 mPa-s in still another embodiment. If the viscosity of the gel layer resin formulation is less than the described viscosities the gel layer will have a tendency to sag or drip off the mandrel used in the winding process and may lead to inhomogeneous distribution of the contaminant removal mechanism in the inner layer of the composite pipe. If the viscosity of the gel layer resin formulation is greater than the described viscosities then the mixed formulation may be too viscous to apply and may lead to inhomogeneous distribution of the contaminant removal mechanism in the inner layer of the composite pipe.
For example, the gel time of the first resin formulation can generally be from about 2 minutes to about 50 minutes in one embodiment, from about 3 minutes to about 30 minutes in another embodiment, and from about 5 minutes to about 20 minutes in still another embodiment. If the gel time of the resin formulation is too short, then the application of the gel layer will become very difficult and adequate bonding may not be achieved between the fiber-free region and fiber-rich region.
The epoxy resin used to form the gel layer can include, for example, a bisphenol-A-based resin, a bisphenol-F-based resin, other thermosetting resins, and mixtures thereof. The formulation for forming the gel layer may also contain other optional compounds such as a monofunctional reactive diluent (including for example, cresyl glycidyl ether, butyl glycidyl ether, and the like.), a di-functional reactive diluent (including for example butanediol digylcidyl ether, butane dioxide, and the like.), a non-reactive diluent (including for example dibutyl phthalate and phenolic compounds), a filler (including for example carbon black, titanium dioxide, and the like.); and mixtures thereof.
In a preferred embodiment, the epoxy useful in the process of the present invention may include for example, one or more bisphenol-A-based resins, bisphenol-F-based resins, and mixtures thereof.
One of the beneficial properties of the epoxy resin used in the present invention is its initial viscosity as specified in the ranges described above so that dripping of the mixed resin formulation off the mandrel does not occur.
The curing agent used to cure the epoxy resin present in the gel layer can include, for example, an amine, a polyamide, a polyamidoamine, a phenol, an amino-formaldehyde, a carboxylic acid functional polyester, an anhydride, a polysulfide, a polymercaptan; and mixtures thereof.
In a preferred embodiment, the curing agent useful in the process of the present invention may include for example, one or more aliphatic amines, cycloaliphatic amines, polyetheramines, and mixtures thereof.
One of the beneficial properties of the curing agent is a low equivalent hydrogen weight (no greater than 60 amine hydrogen equivalent weight [AHEW]) so that only a small amount of the amine curing agent is needed. A high hydrogen equivalent weight will need a large amount of curing agent and will decrease the viscosity of the gel-layer so that it is un-usable.
The particulate material added to the gel layer can include, for example, any particulate in a micro or nanoscale size that is advantageous for capturing contaminants and removing the contaminants from a contaminated liquid fluid such as radionuclides where the particulate and contaminant come into direct contact with one another in the fiber-free region containing contaminant-capturing particles. For example, the contaminant-capturing particulate material may include barium sulfate (BaSO4).
The contaminant-capturing particulate used in the present invention may include, for example, metal-sulfates, metal oxides, and/or any combination thereof. The contaminant-capturing particles are solid at room temperature. The contaminant-capturing particulate may have a melting point greater than 500° C., greater than 800° C., and/or greater than 1000° C. The melting point of the contaminant-capturing particulate may be less than 2500° C. Exemplary metal-sulfates include alkali metal-sulfates and alkaline earth metal-sulfates. Exemplary metal-sulfates include barium sulfate, strontium sulfate, and mixtures thereof. In one preferred embodiment, the contaminant-capturing particulate is barium sulfate. Exemplary metal oxides include manganese oxides such as manganese(II) oxide (MnO), manganese(II,III) oxide (Mn3O4), manganese(III) oxide (Mn2O3), manganese dioxide (MnO2), and manganese(VII) oxide (Mn2O7). Exemplary manganese oxide based minerals include birnessite, hausmannite, manganite, manganosite, psilomelane, and pyrolusite.
The contaminated liquid that is processed using a fiber-reinforced composite article of the present invention may include, for example water, brine, a blend of crude oil and water, or a blend of crude oil and brine.
In a preferred embodiment, the particulate material useful in the process of the present invention may include for example, one or more forms, shapes or sizes of barium sulfate (BaSO4). One of the beneficial properties of the particulate material includes the capability of the particulate material to capture and entrap a radionuclide by the radionuclide coming into direct contact with the particulate material.
The concentration of the particulate material used in the present invention may range generally from about 5 wt % to about 90 wt % in one embodiment, from about 15 wt % to about 85 wt % in another embodiment, and from about 25 wt % to about 80 wt % in still another embodiment. If there is too little particulate material in the gel layer, there may not be sufficient material to capture the contaminant of interest. If there is too much particulate material in the gel layer, inter-layer and intra-layer bonding may not be sufficient to form a homogenous article.
The dispersing aid added to the gel layer can include, for example, any additive that decreases settling of additives for contaminant removal. In a preferred embodiment, the dispersing aid useful in the process of the present invention may include for example, one or more polysiloxane copolymer that decreases settling of inorganic additive for radionuclide removal.
One of the beneficial properties of the dispersing aid is its ability to keep the particle for radionuclide removal from settling in the gel-layer.
The concentration of the dispersing aid used in the present invention may range generally from about 0 wt % to about 2 wt % in one embodiment, from about 0.25 wt % to about 1.5 wt % in another embodiment, and from about 0.5 wt % to about 1 wt % in still another embodiment. The use of too little dispersing aid will lead to inefficiently dispersed particles. The use of too much dispersing aid will affect the performance of the contaminant removal mechanism.
Optional additives that can be added to the formulation for forming the gel layer may include for example monofunctional reactive diluents (including for example cresyl glycidyl ether, butyl glycidyl ether, and the like.), di-functional reactive diluents (including for example butanediol diglycidyl ether, butane dioxide, and the like), non-reactive diluents (including for example dibutyl phthalate and phenolic compounds) useful for modifying the viscosity of the gel layer such that advantageously the gel layer can be processed through the process of the present invention.
The concentration of the optional additives used in the present invention may range generally from 0 wt % to about 5 wt % in one embodiment, from about 0.1 wt % to about 3 wt % in another embodiment, and from about 0.5 wt % to about 1 wt % in still another embodiment. If too much viscosity modifier is used (e.g., >5 wt %), the mechanical properties of the formulation may be adversely impacted.
In one embodiment, an accelerator may be used as an optional additive that can be added to form the gel layer. For example, a gel or cure accelerator useful for accelerating the rate of crosslinking within the curing formulation may be used.
The concentration of the optional accelerator used in the present invention may range generally from 0 wt % to about 3 wt % in one embodiment, from about 0.1 wt % to about 2 wt % in another embodiment, and from about 0.5 wt % to about 1 wt % in still another embodiment. If too much gel or cure accelerator is added to the gel layer formulation, then the formulation may be too reactive and a homogenous gel layer may not be achieved.
Another optional additive that can be added to form the gel layer may include for example fillers (including for example carbon black, titanium dioxide, and the like) useful for providing advantageous properties that the gel layer could not achieve without such as a thermal barrier, wear reduction barrier and the like.
The concentration of the filler used in the present invention may range generally from 0 wt % to about 25 wt % in one embodiment, from about 0.1 wt % to about 15 wt % in another embodiment, more preferably from about 0.5 wt % to about 10 wt % in still another embodiment. If too much filler beyond the above concentrations is added to the formulation, then the formulation may be too reactive and a homogenous gel-layer may not be achieved. If too little filler outside the ranges above is used, than the desired properties achieved through incorporation of the filler may not be achieved.
The second polymer fiber-rich or fiber-reinforced region of the composite is formed using a composition, system or formulation containing the following compounds or components: (i) a polymer resin, (ii) a curing agent for curing the resin, and (iii) a fiber reinforcement material.
The second formulation which can be used in the present invention may include a conventional formulation for filament winding with low viscosity (for example, from about 350 mPa-s to about 600 mPa-s) for homogenous fiber bundle impregnation and long gel times (for example, >6 hours at 25° C.). For example, the viscosity of the second formulation can generally be from about 200 mPa-s to about 1000 mPa-s in one embodiment, from about 300 mPa-s to about 800 mPa-s in another embodiment, and from about 350 mPa-s to about 600 mPa-s in still another embodiment. The viscosity of the formulation needs to be in accordance with a traditional filament winding system. Too high a viscosity will result in poor fiber bundle impregnation. Too low a viscosity will result in resin drainage from the fiber bundle.
It is desired to achieve homogenous fiber bundle impregnation such that the resulting structure will perform as designed without any deleterious amount of wet out of the resin formulation as can be determined by techniques known in the art. For example, the gel time of the second formulation can generally be from about 1 hour (hr) to about 16 hr in one embodiment, from about 2 hr to about 12 hr in another embodiment, and from about 4 hr to about 8 hr in still another embodiment. If the gel time is too short, the entire composite structure may not be formed before the curing reaction occurs, leading to a heterogeneous laminate structure. There are no major consequences to having too long a gel time beyond the 16 hours discussed about other than the process would be uneconomical and inefficient.
The polymer resin used to form the fiber-rich (fiber-reinforced) layer can include, for example, a bisphenol-A-based resin, a bisphenol-F-based resin, a monofunctional reactive diluent (including for example, cresyl glycidyl ether, butyl glycidyl ether, and the like.), di-functional reactive diluents (including for example, butanediol digylcidyl ether, butane dioxide, and the like.), non-reactive diluents (including for example, dibutyl phthalate and phenolic compounds), fillers (including for example, carbon black, titanium dioxide, and the like.), and mixtures thereof. Additionally, a curing agent is used to form the cross-linked polymer network that may be comprised of polyamides, polyamidoamines, phenol and amino-formaldehydes, carboxylic acid functional polyesters, anhydrides and polysulfides and polymercaptans; and mixtures thereof.
In a preferred embodiment, the polymer resin useful in the process of the present invention may include for example, one or more bisphenol-A-based resins, one or more di-functional reactive diluents, and mixtures thereof.
One of the beneficial properties of the polymer resin of the second formulation is its low initial viscosity, (i.e., the formulation which includes the resin, additives, fillers and curing agent). For example, the initial viscosity of the formulation can be from about 350 mPa-s to about 600 mPa-s.
The concentration of the polymer resin used in the present invention may range generally from about 60 wt % to about 99 wt % in one embodiment, from about 70 wt % to about 90 wt % in another embodiment, and from about 80 wt % to about 85 wt % in still another embodiment. Use of too much reactive diluent (and therefore reducing the amount of epoxy resin in the overall formulation to below 60 wt %) will significantly and adversely impact the thermal and mechanical properties of the final cured composite article.
The curing agent used to cure the polymer resin present to form the fiber-reinforced polymer region can include, for example, any of the curing agents described above with reference to the gel layer. For example, the curing agent can be an amine, a polyamide, a polyamidoamine, a phenol, an amino-formaldehyde, a carboxylic acid functional polyester, an anhydride, a polysulfide, a polymercaptan; and mixtures thereof.
In a preferred embodiment, the curing agent useful in the process of the present invention may include for example, one or more aliphatic amines, cycloaliphatic amines, polyetheramines, and mixtures thereof.
The reinforcement material used to form the fiber-rich region layer can include, for example, discontinuous or continuous glass fibers (e.g., e-glass, s-glass, and the like), carbon fibers (e.g., polyacrylonitrile [PAN] fibers and pitch based fibers), aramid fibers, natural fibers, and mixtures thereof.
In a preferred embodiment, the reinforcement material useful in the process of the present invention may include for example, one or more continuous or discontinuous glass fibers, continuous or discontinuous carbon fibers, and mixtures thereof.
The concentration of the reinforcement material used in the present invention may range generally from about 10 wt % to about 90 wt % in one embodiment, from about 15 wt % to about 85 wt % in another embodiment, and from about 20 wt % to about 80 wt % in still another embodiment. The reinforcing material needs to have such a presence that the composite article meets electrical, thermal and mechanical performance targets for the industry. Too low or too high an amount of reinforcing material will cause detrimental issues in the aforementioned performances.
A beneficial optional additive that can be added to form the gel layer may include for example monofunctional reactive diluents (including for example cresyl glycidyl ether, butyl glycidyl ether, and the like), di-functional reactive diluents (including for example butanediol digylcidyl ether, butane dioxide, and the like), non-reactive diluents (including for example dibutyl phthalate and phenolic compounds, and the like) which is capable of modifying the viscosity of the gel-layer to be advantageous for processing.
The concentration of the optional additive, when used in the present invention, may range generally from 0 wt % to about 5 wt % in one embodiment, from about 0.1 wt % to about 3 wt % in another embodiment, from about 0.5 wt % to about 1 wt % in still another embodiment. If too much viscosity modifier is used (e.g., >5 wt %), the mechanical properties of the formulation may be adversely impacted.
A beneficial optional additive that can be added to form the gel layer may include for example a gel or a cure accelerator which is adapted to accelerating the rate of crosslinking within the curing formulation.
The concentration of the optional additives used in the present invention may range generally from 0 wt % to about 3 wt % in one embodiment, from about 0.1 wt % to about 2 wt % in another embodiment, and from about 0.5 wt % to about 1 wt % in still another embodiment. If too much gel or cure accelerator is added then the formulation may be too reactive and a homogenous gel-layer may not be achieved.
In general, the process for manufacturing a fiber-reinforced composite article useful for contaminant removal such as radionuclide removal includes the steps of:
(A) disposing a gel material layer onto the surface of a mandrel; (B) introducing a fiber reinforcement into a polymer resin impregnation means; (C) impregnating the fiber reinforcement of step (B) with a polymer resin to form a polymer fiber-reinforced layer material; (D) disposing the resin impregnated fiber-reinforced layer material of step (C) onto the surface of the gel material layer of (A); and (E) bonding polymer gel material layer to the polymer fiber-reinforced layer material by curing the combination of the gel material layer and the resin impregnated fiber-reinforced layer material to form at least one single layer of a fiber-reinforced composite including at least three regions in said at least one single layer. The three regions include the following:
The first polymer fiber-free region includes an inner surface and an outer surface; and the second polymer fiber-rich region includes an inner surface and an outer surface. The outer surface of the first polymer fiber-free region is integrally bonded to the inner surface of the second polymer fiber-rich region forming the at least one third polymer boundary region disposed between the first polymer fiber-free region and the second polymer fiber-rich region. The third polymer boundary region further comprises a contiguous boundary of a non-delineated width between the first polymer fiber-free region and the second polymer fiber-rich region. And, the first polymer fiber-free region is integrally attached to the second polymer fiber-rich region such that the first polymer fiber-free region and second polymer fiber-rich region are infused together forming the at least one third polymer boundary region.
More specifically, the first step of the process includes admixing the required components to make the gel layer such as for example: (i) an epoxy resin, (ii) a curing agent such as an amine curing agent for curing the epoxy resin, (iii) a particulate material; and
(iv) any optional compounds, for example, a dispersing aid. Then the mixture can be processed under conditions for forming a gel layer including heating the above mixture at a predetermined temperature and time to form an effective gel layer. The temperature of heating can generally be in the range of from about 15° C. to about 60° C. in one embodiment, from about 20° C. to about 40° C. in another embodiment, and from about
22° C. to about 30° C. in still another embodiment. If the temperature of the formulation is too low, this may cause a significant increase in viscosity (e.g., >40,000 mPa-s) resulting in an inability to process the gel layer onto the mandrel. If the temperature of the formulation is too high, this may case a significant increase in the reactivity of the gel layer and may not allow sufficient time to apply the gel layer to the mandrel before curing.
The heating time to form the gel layer may be, for example, generally from about 5 min to about 120 min in one embodiment, from about 10 min to about 60 min in another embodiment, and from about 15 min to about 45 min in still another embodiment. In general, the heating time for the gel layer will depend on the composition and reactivity of the gel layer. Too high of a heating time may increase the temperature such that the curing reaction is induced and the gel layer cannot be properly applied to the mandrel. Too low of a heating temperature and the viscosity of the gel layer formulation may be too high such that the gel layer may not be homogenously applied to the mandrel.
The process of the present invention for forming the gel layer may be a batch process, an intermittent process, or a continuous process using equipment well known to those skilled in the art.
Once the composition for the gel layer is made, the gel layer formulation is applied to the mandrel of a filament winding process.
The process includes the step of admixing the compounds or components required to make the second polymer fiber-rich composite layer of the composite: (i) a polymer resin, (ii) a curing agent for curing the resin, and (iii) a fiber reinforcement material. Then the mixture can be processed under conditions for forming a fiber-reinforced layer generally including the steps of introducing a fiber reinforcement into a polymer resin impregnation means; and impregnating the fiber reinforcement with a polymer resin to form a second polymer fiber-reinforced layer material.
Generally, to form the polymer fiber-reinforced layer, the impregnation of the fiber reinforcement with a polymer resin is carried out at a predetermined temperature and time to form an effective fiber-reinforcement layer. The temperature of heating can generally be in the range of from about 15° C. to about 40° C. in one embodiment, from about 20° C. to about 35° C. in another embodiment, and from about 25° C. to about 30° C. in still another embodiment. Any heating outside of the above range may cause adverse effects to the desired rheological behavior of the mixed formulation. For example, temperatures below 15° C. may cause the mixed formulation's viscosity to increase to a level that is un-usable in the methods described above as well as slowing the epoxy-amine reaction to such a low rate that the gel-point of the material cannot be reached. And, temperatures above 40° C. may lower the viscosity to such a state that the material will drip from the mandrel and may not form a homogenous layer on the desired surface of the composite article. Additionally, a temperature higher than 40° C. may prematurely induce the autocatalytic curing reaction and render the mixed formulation un-usable.
If the composite article is heated for too little time, the cross-linking reaction associated with thermoset matrices may not be complete with the resulting effect of producing an underperforming article.
The process of the present invention for forming the fiber reinforced layer may be a batch process, an intermittent process, or a continuous process using equipment well known to those skilled in the art. The heating time to form the fiber reinforced composite may be, for example, generally from about 1 hour to about 24 hours in one embodiment, from about 1.5 hour to about 12 hours in another embodiment, and from about 2 hours to about 8 hours in still another embodiment.
Upon bonding the combined fiber-reinforced layer and gel layer to form a single composite article a first polymer fiber-free region, a second polymer fiber-rich region, and a third polymer boundary region is formed in the single composite article.
As aforementioned, the first polymer fiber-free region includes an inner surface and an outer surface; and the second polymer fiber-rich region includes an inner surface and an outer surface. The outer surface of the first polymer fiber-free region is integrally bonded to the inner surface of the second polymer fiber-rich region forming the at least one third polymer boundary region disposed between the first polymer fiber-free region and the second polymer fiber-rich region. The third polymer boundary region further comprises a contiguous boundary of a non-delineated width between the first polymer fiber-free region and the second polymer fiber-rich region. And the first polymer fiber-free region is integrally attached to the second polymer fiber-rich region such that the first polymer fiber-free region and second polymer fiber-rich region are infused together forming the at least one third polymer boundary region.
Some non-limiting examples of enduse applications for the composite product of present invention may include, for example, in manufacturing an article by filament winding, pultrusion, infusion, hand lay-up, or a combination of such methods. The composite article can be for example a conduit, a pipe or piping for use in downhole wells in the oil and gas industry; or a pipe for flowing a liquid fluid therein and removing contaminants (e.g., a radionuclide) present in the liquid fluid from the liquid such as contaminated fluid from hydraulic fracturing operations.
Exemplary embodiments that may incorporate any or all of the above-discussed features, include, the following:
A fiber-reinforced composite article useful for contaminant removal comprising at least one single layer of a fiber-reinforced composite including the following regions in said at least one single layer: (a) at least one first polymer fiber-free region containing material adapted for removing contaminants, said contaminant removal material integrated into the first polymer fiber-free region; said first polymer fiber-free region including an inner surface and an outer surface; (b) at least one second polymer fiber-rich region containing fiber reinforcement material; said second polymer fiber-rich region including an inner surface and an outer surface; and (c) at least one third polymer boundary region containing a portion of the first polymer fiber-free region and a portion of the second polymer fiber-rich region. Whereas, the outer surface of the first polymer fiber-free region is integrally bonded to the inner surface of the second polymer fiber-rich region forming the at least one third polymer boundary region disposed between the first polymer fiber-free region and the second polymer fiber-rich region; wherein the third polymer boundary region further comprises a contiguous boundary of a non-delineated width between the first polymer fiber-free region and the second polymer fiber-rich region; and wherein the first polymer fiber-free region is integrally attached to the second polymer fiber-rich region such that the first polymer fiber-free region and second polymer fiber-rich region are infused together forming the at least one third polymer boundary region.
A process for manufacturing a fiber-reinforced composite article useful for contaminant removal at least one single layer of a fiber-reinforced composite comprising the steps of: (i) providing a formulation for forming at least one first polymer fiber-free gel layer; (ii) applying the first polymer fiber-free gel layer formulation of (i) onto a mandrel of a filament winding process such that the polymer fiber-free gel layer formulation forms a polymer fiber-free gel layer of a predetermined thickness on the mandrel; (iii) providing a formulation for forming at least one second polymer fiber-rich layer; (iv) applying the second polymer fiber-rich layer formulation of (iii) onto the surface of the polymer fiber-free gel layer produced in step (ii) such that the second polymer fiber-rich layer formulation forms a second polymer fiber-rich layer of a predetermined thickness disposed on the first polymer fiber-free gel layer which is disposed on the mandrel; and (v) curing the first polymer fiber-free gel layer and second polymer fiber-rich layer to form at least one single layer of a fiber-reinforced composite; wherein the at least one single layer of a fiber-reinforced composite includes the following regions in said single layer: (a) at least one first polymer fiber-free region containing material adapted for removing contaminants, said contaminant removal material integrated into the first polymer fiber-free region; said first polymer fiber-free region including an inner surface and an outer surface; (b) at least one second polymer fiber-rich region containing fiber reinforcement material; said second polymer fiber-rich region including an inner surface and an outer surface; and (c) at least one third polymer boundary region containing a portion of the first polymer fiber-free region and a portion of the second polymer fiber-rich region. Whereas, the outer surface of the first polymer fiber-free region is integrally bonded to the inner surface of the second polymer fiber-rich region forming the at least one third polymer boundary region disposed between the first polymer fiber-free region and the second polymer fiber-rich region; wherein the third polymer boundary region further comprises a contiguous boundary of a non-delineated width between the first polymer fiber-free region and the second polymer fiber-rich region; and wherein the first polymer fiber-free region is integrally attached to the second polymer fiber-rich region such that the first polymer fiber-free region and second polymer fiber-rich region are infused together forming the at least one third polymer boundary region.
An apparatus for manufacturing a fiber-reinforced composite article useful for contaminant removal comprising: (I) a means for disposing a gel material layer onto the surface of a mandrel; (II) a means for introducing a fiber reinforcement into a resin impregnation means; (III) a resin impregnation means for impregnating the fiber reinforcement of (II) with a polymer resin to form a polymer fiber-reinforced layer material; (IV) a means for disposing the resin impregnated fiber-reinforced layer material of (III) onto the surface of the gel material layer of (I); and (V) a means for curing the combination of the gel material layer and the resin impregnated fiber-reinforced layer material to form at least one single layer of a fiber-reinforced composite including the following regions in said at least one single layer: (a) at least one first polymer fiber-free region containing material adapted for removing contaminants, said contaminant removal material integrated into the first polymer fiber-free region; said first polymer fiber-free region including an inner surface and an outer surface; (b) at least one second polymer fiber-rich region containing fiber reinforcement material; said second polymer fiber-rich region including an inner surface and an outer surface; and (c) at least one third polymer boundary region containing a portion of the first polymer fiber-free region and a portion of the second polymer fiber-rich region. Whereas, the outer surface of the first polymer fiber-free region is integrally bonded to the inner surface of the second polymer fiber-rich region forming the at least one third polymer boundary region disposed between the first polymer fiber-free region and the second polymer fiber-rich region; wherein the third polymer boundary region further comprises a contiguous boundary of a non-delineated width between the first polymer fiber-free region and the second polymer fiber-rich region; and wherein the first polymer fiber-free region is integrally attached to the second polymer fiber-rich region such that the first polymer fiber-free region and second polymer fiber-rich region are infused together forming the at least one third polymer boundary region.
A process for manufacturing a fiber-reinforced composite article useful for contaminant removal comprising the steps of: (A) disposing a gel material layer onto the surface of a mandrel; (B) introducing a fiber reinforcement into a polymer resin impregnation means; (C) impregnating the fiber reinforcement of step (B) with a polymer resin to form a polymer fiber-reinforced layer material; (D) disposing the resin impregnated fiber-reinforced layer material of step (C) onto the surface of the gel material layer of (I); and (E) bonding polymer gel material layer to the polymer fiber-reinforced layer material by curing the combination of the gel material layer and the resin impregnated fiber-reinforced layer material to form at least one single layer of a fiber-reinforced composite including the following regions in said at least one single layer: (a) at least one first polymer fiber-free region containing material adapted for removing contaminants, said contaminant removal material integrated into the first polymer fiber-free region; said first polymer fiber-free region including an inner surface and an outer surface; (b) at least one second polymer fiber-rich region containing fiber reinforcement material; said second polymer fiber-rich region including an inner surface and an outer surface; and (c) at least one third polymer boundary region containing a portion of the first polymer fiber-free region and a portion of the second polymer fiber-rich region. Whereas, the outer surface of the first polymer fiber-free region is integrally bonded to the inner surface of the second polymer fiber-rich region forming the at least one third polymer boundary region disposed between the first polymer fiber-free region and the second polymer fiber-rich region; wherein the third polymer boundary region further comprises a contiguous boundary of a non-delineated width between the first polymer fiber-free region and the second polymer fiber-rich region; and wherein the first polymer fiber-free region is integrally attached to the second polymer fiber-rich region such that the first polymer fiber-free region and second polymer fiber-rich region are infused together forming the at least one third polymer boundary region. The process may further provide for the exposed surface area of the material adapted for removing contaminants is increased by the further steps of: (v) applying a pre-processing treatment to the surface upon which the composite article is formed; and (vi) applying a post-processing treatment to the composite article. The post-processing treatment may be a mechanical, thermal, electrical or chemical post-processing method.
A process for removing contaminants from a liquid fluid in contact with a fiber-reinforced composite article comprising the steps of: (a) providing a fiber-reinforced composite article useful for contaminant removal comprising at least one single layer of a fiber-reinforced composite including the following regions in said at least one single layer: (a) at least one first polymer fiber-free region containing material adapted for removing contaminants, said contaminant removal material integrated into the first polymer fiber-free region; said first polymer fiber-free region including an inner surface and an outer surface; (b) at least one second polymer fiber-rich region containing fiber reinforcement material; said second polymer fiber-rich region including an inner surface and an outer surface; and (c) at least one third polymer boundary region containing a portion of the first polymer fiber-free region and a portion of the second polymer fiber-rich region. Whereas, the outer surface of the first polymer fiber-free region is integrally bonded to the inner surface of the second polymer fiber-rich region forming the at least one third polymer boundary region disposed between the first polymer fiber-free region and the second polymer fiber-rich region; wherein the third polymer boundary region further comprises a contiguous boundary of a non-delineated width between the first polymer fiber-free region and the second polymer fiber-rich region; and wherein the first polymer fiber-free region is integrally attached to the second polymer fiber-rich region such that the first polymer fiber-free region and second polymer fiber-rich region are infused together forming the at least one third polymer boundary region. Further comprising, (β) contacting a liquid fluid with the first polymer fiber-free region containing material adapted for removing contaminants such the material adapted for removing contaminants in the first polymer fiber-free region adsorbs one or more contaminants from the liquid fluid.
The following examples and comparative examples further illustrate the present invention in more detail but are not to be construed to limit the scope thereof.
In the following Examples, various materials, terms and designations are used and are explained as follows:
EEW stands for epoxide equivalent weight.
AHEW stands for amine hydrogen equivalent weight.
D.E.R. 383 is an epoxy resin having an EEW of 171 and commercially available from The Dow Chemical Company.
D.E.N. 438 is an epoxy resin having an EEW of 179 and commercially available from The Dow Chemical Company.
VORAFORCE™ TW 120 is a formulated amine hardener having an AHEW of 36 and commercially available from The Dow Chemical Company.
BYK 940 is a dispersion-aiding additive and commercially available from Altana.
BaSO4 powder was obtained from Excalibar Minerals.
Standard measurements, analytical equipment and methods were used in the Examples as follows:
EEW Measurements
The EEW of the resin was measured according to the procedure described in ASTM D-1652 (2011).
AHEW Measurements
The AHEW of the resin was calculated after finding the amine value according to the procedure described in ISO 9702 (1996).
Viscosity Measurements
The viscosity of the resin was measured according to the procedure described in ASTM D-445(2015) at 25° C.
General Procedure of Filament Winding Process
A composite pipe of the present invention can be manufactured using a filament winding process. Filament winding is one of the more important composite production methods in terms of number of users and total number of fabricated parts. The filament winding process begins with fiber tows coming from spools of glass or carbon fibers mounted on a creel. The fibers are gathered together and collected through a type of fiber guide (i.e., a “comb”) to form a band. The number of the fibers brought together determines the band width. The band is pulled through a resin bath (containing a resin and a hardener mixed together such that the formulation is active). The resin from the resin bath impregnates the pulled fiber tow. The fibers are then drawn through a roller or wiper system to achieve the desired resin content on the fibers; and then the fibers are drawn through a payoff. The “payoff” is the point at which the fiber contacts a moving carriage and directs the fibers on to a rotating mandrel. This method of production is efficient for producing any type of cylindrical part. Furthermore, as the complexity and capability of filament winding machines increases other non-cylindrical parts can also be wound using a filament winding method.
General Procedure of Hand-Lay Up
A composite article of the present invention, alternatively, can be manufactured through a hand lay-up method utilizing two different production steps. Hand lay-up is the simplest and oldest open molding method of the composite fabrication processes. It is a low volume, labor intensive method suited especially for large components. Glass, carbon or other reinforcing mat or woven fabric or roving is positioned manually in the open mold, and resin is poured, brushed, or sprayed over and into the glass plies. Entrapped air is removed manually with squeegees or rollers to complete the laminates structure. Curing is initiated by a catalyst in the resin formulation, which hardens the fiber reinforced resin composite without external heat. Post cure to achieve higher mechanical properties is often required.
Two different formulated compositions were used to produce a single composite article using a filament winding process. The two compositions are described in Table I. The two formulations or compositions were designed for advantageously having a fiber-free (i.e., resin-rich) layer containing barium sulfate particles near the surface of the composite article (“first composition”) and a fiber-rich (“second composition”) layer chemically bonded to the resin-rich layer providing mechanical reinforcement.
The first composition (“Gel Layer” in Table I), was applied as a gel layer to a rotating mandrel and was designed to have high initial viscosity (e.g., >20,000 mPa-s) to prevent sagging and dripping during application of gel layer onto the mandrel; and a fast gel time (e.g., <1 hour at 25° C.) to advantageously allow the gel layer to be processed more readily.
The second composition (“Fiber-Reinforced Layer” in Table I) was designed as a low viscosity formulation (e.g., ˜500 mPa-s) for a traditional open-bath filament winding manufacturing process. The low viscosity of the second composition ensures thorough and homogenous fiber wet out during the composite article manufacture. The second composition has a longer gel time (e.g., >6 hours at 25° C.) than the first composition; and has desirable toughness properties upon curing (e.g., K1C Mode Fracture Toughness ˜0.75 MPa-m1/2).
In this Example 2, two different polymer compositions are used to produce a composite article using a hand lay-up process. The two polymer compositions are described in Table II. The two formulations or compositions are designed for advantageously having a fiber-free (i.e., resin-rich) layer containing barium sulfate particles near the surface of the composite article (“first composition”) and a fiber-rich (“second composition”) layer chemically bonded to the resin-rich layer providing mechanical reinforcement.
The first polymer composition (“Gel Layer” in Table II), is applied as a gel layer to a substrate and is designed to have high initial viscosity (e.g., >20,000 mPa-s) to prevent sagging and dripping during application of gel layer; and a fast gel time (e.g.,
<1 hour at 25° C.) to advantageously allow the gel layer to be processed more readily.
The second polymer composition (“Fiber-Reinforced Layer” in Table II) is a commercially available conventional formulation have a low viscosity for homogenous fiber bundle impregnation; and exhibiting a long gel time (e.g., >6 hours at 25° C.).
Three trials were run to quantify the amount of radionuclide removal using a fiber-reinforced composite of the present invention as follows:
General Procedure of Testing
In general, the experiments related to the absorption of Radium-226 (Ra-226) were carried out using two granular materials containing different mass fractions of barium sulfate (GM1 and GM2). The three trials were: (1) both materials were tested at 50 degrees Celsius (° C.), 70° C. and 90° C., (2) material GM1 in brine and in a modified brine lacking barium sulfate are tested at 90° C., and (3) barium sulfate in brine and in a modified brine lacking barium sulfate are tested at 90° C.
The general procedure included contacting the two materials with brine containing Ra-226 at three temperatures. The brine contained chlorides of calcium, sodium and barium. Samples of brine were taken at various times and analyzed to assess the amount of Ra-226 remaining in the brine. The amount of Ra-226 absorbed by the materials was assessed at the end of the experiment.
Samples of material and brine were placed in 500 ml glass bottles and held at a fixed temperature. A water bath was used for the 50° C. trial and electric ovens were used for the 70° C. and the 90° C. trials. The mixture was mixed by swirling several times during each experiment.
A standard solution of Ra-226, commercially available from Isotope Products Laboratories, was diluted with dilute nitric acid to obtain a working solution. Portions of the working solution were then dispensed for each of the trials by pipetting.
One-liter lots of brine are prepared by weighing. The brine contains 5.0 wt %, 2.6 wt %, and 0.07 wt % of NaCl, CaCl2 and BaCl2.2H2O, respectively. The pH of the brine was adjusted to between 7.5 and 8.0 using solutions of sodium hydroxide and hydrochloric acid.
A portion of brine was weighed out for each test. A solution (2.457 milliliters (mL)) containing approximately 5,000 picoCuries of Ra-226 was added to the brine, and the pH of the brine was readjusted. One of the brine portions was added to a
pre-weighed sample of material to start each test.
The detection of Ra-226 in brine samples was determined by Liquid Scintillation Counting (LSC). After the Ra-226 exposure to the fiber composite was complete, the detection of Ra-226 captured in the contaminant-capturing particles of the material was determined by Gamma-ray Spectrometry.
Before LSC, each aliquot was gently evaporated in order to expel Rn-222, which interfered with the Ra-226 measurement. Two counting windows were used: one registered counts due to both Ra-226 and Rn-222 and the other registered counts only due to Rn-222. A correction factor was established using water from a Radon generator and was used to correct for Rn-222 interference on Ra-226.
45 g of material and 180 g of brine are used for each test. At each sampling, the bottles are weighed and aliquots are withdrawn from opened bottles using an air displacement pipette. After the final sampling, the material is removed from the exposure bottle by slurrying with deionized water and was then briefly rinsed with further deionized water before packaging for gamma-ray spectrometry. Results were corrected for the effects of pipetting hot liquids and for losses due to evaporation. Four control preparations were tested to assess any contribution from the materials used. The results of the first trial are described in Tables III and IV.
(a)count rate divided by the count rate for a sample taken at the start of the experiment
(b)1 standard deviation, computed from counting statistics
The results were corrected for interference due to Radon, losses due to evaporation and the effect of hot solutions on the operation of pipettes. Uncertainty arising from pipetting could not be assessed and was not included in the estimates given above.
90 g of material GM1 and 360 g of brine were used for each test. One lot of brine contained barium, the other did not. In both cases, the pH was adjusted to 7.5 to 8.0. The contact was carried out at 90° C. Each portion of material was rinsed three times with deionized water to remove fines before addition of brine. Slight cloudiness was observed in the final rinse.
At each sampling, the bottles were weighed and aliquots were withdrawn from bottles using a syringe and a thin tube that passed through a small hole in the bottle cap; and placed in pre-weighed vials. The amount collected was determined by re-weighing the vials, and was included in calculations.
The brine was sampled before mixing with material, immediately after mixing, at 3 days and at 7 days. Duplicate aliquots were taken at 3 days and 7 days. After the final sampling, the brine was thoroughly drained from the material and the material was then packaged for gamma-ray spectrometry. The results of the second trial are described in Tables V and VI.
(a)count rate divided by the count rate for a sample taken before the start of the experiment
(b)1 standard deviation, computed from counting statistics
0.72 g of barium sulfate and 360 g of brine were used for each test. One lot of brine contained barium, the other did not. In both cases, the pH was adjusted to 7.5 to 8.0. The contact was carried out at 90° C.
At each sampling, the bottles were weighed and aliquots were withdrawn from bottles using a syringe and a thin tube that passed through a small hole in the bottle cap, and placed in pre-weighed vials. The amount collected was determined by re-weighing the vials, and was included in calculations.
The brine was sampled before mixing with barium sulphate, immediately after mixing at 3 days. Duplicate aliquots were taken at 3 days. As the barium sulphate was initially too finely divided to settle, the initial portion was filtered. By 3 days, filtering was unnecessary.
After the final sampling, the barium sulfate was collected by filtering, using filtrate to collect as much of the still very finely divided solid as possible. There may have been small losses to the walls of the bottle. The filters were then packaged for gamma-ray spectrometry. The results of the third trial are described in Tables VII and VIII.
(a)count rate divided by the count rate for a sample taken before the start of the experiment
(b)1 standard deviation, computed from counting statistics
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2016/038466 | 6/21/2016 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62186669 | Jun 2015 | US | |
| 62186645 | Jun 2015 | US | |
| 62186671 | Jun 2015 | US |
