Patent Application
20220411181
This disclosure generally relates to storage tanks, and more particularly to a modular barrier for liquid hydrocarbons and other liquids that are kept in covered or enclosed liquid storage tanks, to reduce the flashing or evaporation of hydrocarbons from the liquid phase into the vapor phase. This disclosure also relates to a modular barrier intended to reduce evaporation of liquids kept in an enclosed storage tank.
Hundreds of thousands of various storage tanks in the United States are used to contain liquids. Storage tanks may be used to store, for example, water, waste, and consumer products such as milk. Storage tanks may also be placed in several locations such as on a vehicle or above or below the ground surface. In the oil and gas industry, storage tanks are used to store hydrocarbons at various locations, including oil refineries and smaller, remote tank batteries at oil well sites. Storage tanks for upstream oil and gas production are typically kept at or near atmospheric pressure for safety reasons and to allow the liquid hydrocarbons to be loaded into trucks for transportation to markets.
One issue with these storage tanks is the natural production of vapors. Light hydrocarbons in the crude oil or condensate or produced water (e.g., wastewater)—including methane and other volatile organic compounds, natural gas liquids, hazardous air pollutants, and some inert gases—vaporize or “flash” and collect in the space between the surface of the crude oil and the roof of the storage tank. This flashing of hydrocarbons reduces the volume of the crude oil stored in the tank. For various reasons not the least of which is the expansion and reduction of the vapors due to ambient heating and cooling of the tanks and other working losses, these vapors may be ultimately released to the atmosphere through a pressure safety valve or other vent mechanism.
There are several approaches to handle and control these vapors. One conventional approach is to vent the vapors from the storage tanks directly into the atmosphere. This approach usually releases harmful pollutants into the atmosphere. When relevant governmental regulations are imposed, another approach is to ignite and flare the vapors so that the vapors are combusted. This approach, itself, releases CO2, a greenhouse gas, into the atmosphere. Thus, in the case of increasing governmental regulations, an operator may have to install substantial control devices to mitigate the vapor emissions. In either approach, the venting or burning of vapors represents wasted resources, atmospheric pollution, and reduced oil production.
One way to mitigate the accumulation of vapors inside of a storage tank is to incorporate a movable or floating roof into the design of the storage tank. Some prior art storage tanks in refineries have a cylindrical outer wall with a circular roof that rises and falls within the cylindrical outer wall to match the liquid level in the storage tank. This reduces the loss of vapors from the crude oil and petroleum products. However, these designs are economical only for large storage tanks. U.S. Pat. No. 8,061,552, which is incorporated herein in its entirety by reference, notes that floating-roof storage tanks are commonly between 15 and 400 feet in diameter and hold up to 1.5 million barrels of liquid or more. As such, the floating roofs are incorporated into the design of the storage tank and must be installed when the storage tank is constructed.
In contrast, floating roofs are not economical for smaller storage tanks, particularly for smaller storage tanks that have already been built and would require retrofitting. Normally, these storage tanks hold considerably less than 50,000 barrels of liquid and more frequently less than 5,000 barrels. For example, a storage tank may hold approximately 300 barrels. One example of these smaller storage tanks is a tank that stores oil from low producing wells (a.k.a. stripper wells). Historically, from the very beginnings of the oil industry, these smaller storage tanks have fixed roofs and typically have a small access port, commonly known as the thief hatch, to allow inspection and measuring. These smaller tanks handle vapor formation using the atmospheric vent or combustion approach, and it is uneconomical to retrofit the inside of these smaller storage tanks with a conventional floating roof. In addition, environmental regulations that require burner units or other control devices to be installed may also render the producing oil well uneconomical. Furthermore, combustion units themselves produce large amounts of CO2, a recognized greenhouse gas.
Therefore, there is a need for a device, a system, and/or a method for controlling the production of vapors from hydrocarbon liquids in storage tanks to prevent the loss of crude oil and petroleum products by flashing or evaporation, and to prevent polluting gases, such as emissions produced by the mechanism of flashing or evaporation, from being released into the atmosphere.
It is thus an aspect of embodiments of the present invention to provide a modular barrier that covers a hydrocarbon liquid and/or the accompanying produced water and reduces the release of vapor from the hydrocarbon liquid or produced water. In some embodiments, the modular barrier comprises a plurality of three-dimensional (3D) objects wherein each 3D object is sized to fit through small ports or apertures and into an enclosed volume within a storage tank. The plurality of objects, when inserted into the tank, cover a surface of the stored liquid and conform to the shape of the tank. Such modular barrier is simple to install and can easily conform to tanks of different sizes and shapes. Thus, smaller storage tanks or tanks without floating roofs can utilize various embodiments of the present disclosure. The modular barrier may comprise a plurality of objects of any three-dimensional shape. For example, the following publications and patents describe example shapes that the plurality of objects may take: U.S. Pat. No. 8,342,352; W.O. Patent Publication No. 2015/031680; W.O. Patent Publication No. 2015/031669; U.S. Pat. No. D863605, each of which are incorporated by reference herein in their entireties.
In some embodiments, a system of covering liquids in a closed storage tank to reduce the flashing of vapors during storage is provided comprising: a storage tank having an outer wall and a roof that form an enclosed volume, said storage tank; a liquid at least partially filling said enclosed volume of said storage tank, said liquid having an upper surface; a modular barrier comprising a plurality of objects, wherein the plurality of objects is operably sufficient to cover the upper surface of the liquid and conform to a shape of the storage tank when inserted into the enclosed volume. The plurality of objects will have a density lower than a density of the liquid (which may be, for example, a hydrocarbon liquid) so as to float on the liquid. The plurality of objects align next to each other so as to form the barrier and prevent flashing and/or evaporation of light end hydrocarbons to the atmosphere or vapors within the closed storage tank. The plurality of objects may also form more than one layer to form a multi-layer barrier.
In some embodiments, the plurality of objects may be spheres. In other embodiments, the plurality of objects may be hexagonal prisms and/or other shapes. In some embodiments, the plurality of objects may comprise individual objects. In other embodiments, the plurality of objects may comprise individual objects tethered to each other.
In various embodiments, a method for covering liquids in a covered storage tank to reduce flashing of vapors during storage is provided comprising: storing liquid in a storage tank, the storage tank having an outer wall and a roof that form an enclosed volume, the liquid at least partially filling the enclosed volume of the storage tank, the liquid having an upper surface; and covering the upper surface of the liquid with a modular barrier, the modular barrier comprising a plurality of objects operable to cover the upper surface of the liquid and conform to a shape of the storage tank when inserted into the enclosed volume.
The plurality of objects will have a density lower than a density of the liquid (which may be, for example, a hydrocarbon liquid) so as to float on the liquid. Each of the plurality of objects align next to each other so as to form the barrier and reduce flashing and/or evaporation of light end hydrocarbons to the atmosphere or vapors within the closed storage tank. The plurality of objects may also form more than one layer to form a multi-layer barrier.
In some embodiments, the plurality of objects may be spheres. In other embodiments, the plurality of three-dimensional objects may be in the shape of hexagonal prisms, dodecahedrons, and/or other shapes or polygons. In some embodiments, the plurality of objects may comprise individual objects. In other embodiments, the plurality of objects may comprise individual objects tethered to each other. In various embodiments, the method may further comprise inserting the plurality of objects through the access port .
In at least one embodiment, a system for covering liquids in a covered storage tank to reduce flashing of vapors during storage is provided comprising: a storage tank having an outer wall and a roof that form an enclosed volume, and an access port on the roof; a liquid at least partially filling the enclosed volume of the storage tank, the liquid having an upper surface; and a modular barrier comprising a plurality of objects, wherein the plurality of objects is operable to cover the upper surface of the liquid and conform to a shape of the storage tank and accommodate the various pipes and other objects that may reside within the tank when inserted into the enclosed volume, and wherein a size of each object of the plurality of objects is smaller than a perimeter of the access port, and each object of the plurality of objects is configured to be inserted into or removed from the enclosed volume via the access port.
In some embodiments, a flexible cover as described in U.S. Pat. No. 10,392,185, which is herein incorporated by reference in its entirety, may be used in a storage tank.
These and other advantages will be apparent from the disclosure of the invention(s) contained herein. The above-described embodiments, objectives, and configurations are neither complete nor exhaustive. The Summary of the Invention is neither intended nor should it be construed as being representative of the full extent and scope of the invention. Moreover, references made herein to “the invention” or aspects thereof should be understood to mean certain embodiments of the invention and should not necessarily be construed as limiting all embodiments to a particular description. The invention is set forth in various levels of detail in the Summary as well as in the attached drawings and Detailed Description and no limitation as to the scope of the invention is intended by either the inclusion or non-inclusion of elements, components, etc. in this Summary of the Invention. Additional aspects of the invention will become more readily apparent from the Detailed Description particularly when taken together with the drawings.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the disclosure and together with the general description of the disclosure given above and the detailed description of the drawings given below, serve to explain the principles of the disclosures.
To assist in the understanding of the embodiments of the invention the following list of components and associated numbering found in the drawings is provided herein:
Component No. Component
It should be understood that the drawings are not necessarily to scale, and various dimensions may be altered. In certain instances, details that are not necessary for an understanding of the invention or that render other details difficult to perceive may have been omitted. It should be understood, of course, that the invention is not necessarily limited to the particular embodiments illustrated herein.
The disclosure has significant benefits across a broad spectrum of endeavors. It is the Applicant's intent that this specification and the claims appended hereto be accorded a breadth in keeping with the scope and spirit of the invention being disclosed despite what might appear to be limiting language imposed by the requirements of referring to the specific examples disclosed. To acquaint persons skilled in the pertinent arts most closely related to the invention, a preferred embodiment that illustrates the best mode now contemplated for putting the invention into practice is described herein by, and with reference to, the annexed drawings that form a part of the specification. The exemplary embodiment is described in detail without attempting to describe all of the various forms and modifications in which the invention might be embodied. As such, the embodiments described herein are illustrative, and as will become apparent to those skilled in the arts and may be modified in numerous ways within the scope and spirit of the invention.
Although the following text sets forth a detailed description of numerous different embodiments, it should be understood that the detailed description is to be construed as exemplary only and does not describe every possible embodiment since describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims. To the extent that any term recited in the claims at the end of this patent is referred to in this patent in a manner consistent with a single meaning, that is done for sake of clarity only so as to not confuse the reader, and it is not intended that such claim term by limited, by implication or otherwise, to that single meaning.
Various embodiments of the invention are described herein and as depicted in the drawings. It is expressly understood that although the figures illustrate covers, floating covers, flaps, etc., the invention is not limited to these embodiments.
Now referring to
Turning to
In some embodiments, the stored liquid 86 comprises hydrocarbon liquid. The tank 78 also includes an access port 106 operable to provide an opening for inserting or removing a plurality of objects 102 (or any objects or liquids) into and out of the tank 78. The plurality of objects 102 may comprise a plurality of three-dimensional (3D) objects. The access port 106 may also have a lid 110 for enclosing the access port 106. The access port 106 may be, for example, an opening into the tank 78 and the cover 110 may be a hatch. A vapor space 90 of the tank 78 includes the stored liquid 86 and a modular barrier 94. As previously mentioned, residual gas in the oil and oil vapors may rise to the roof 82 and are emitted through the vent 98. However, such residual gas when emitted through the vent 98 is typically disposed of by flaring or venting directly to the atmosphere. In order to accommodate flaring, installation of additional equipment is required and thus, increases the cost of production. Loss of the residual gas and oil vapors may be mitigated by a modular barrier 94A, 94B, 94C as shown in
The storage tank 78 may also include a conduit 22 (e.g., a downpipe) that channels liquid along a path into the liquid 86 stored in the tank 78. In some embodiments, the storage tank 78 comprises an inlet 18 for the incoming liquid (e.g., oil) on the roof 82 of the tank. The pipe from the well or the separator transports the liquid to the tank and this pipe is attached to a fitting on the top of the tank 78. The liquid enters the inside of the tank 78 through this fitting and the liquid splashes or otherwise falls into the tank 78. This can pose a problem if the modular barrier 94A, 94B, 94C is already deployed in the storage tank 78. The splashing of the liquid on top of the modular barrier exacerbates the generation of vapors. A solution for this is to introduce the liquid 86 below the stored liquid surface. In some embodiments of the present invention, a pipe, hose, or conduit 22 is installed in the interior of the tank 78. This conduit 22 can attach to the inlet 18 fitting on the top of the tank 78 and transport and channel the liquid to the bottom of the tank 78, or at least below a liquid level and below the modular barrier 94A, 94B, 94C in the storage tank so that oil or any other liquid does not splash on top of the modular barrier 94A, 94B, 94C.
In some embodiments, the modular barrier 94A, 94B, 94C may be a modular cover. The modular barrier 94A, 94B, 94C as shown, may cover a surface of the stored liquid 86. When the surface of the stored liquid 86 is covered by the modular barrier 94A, 94B, 94C, the modular barrier 94A, 94B, 94C may prevent the stored liquid 86 (which may be, for example, hydrocarbon liquids) from vaporizing. The barrier 94A, 94B, 94C advantageously prevents flashing of light end hydrocarbons to the atmosphere or vapors within the closed storage tank 78 and/or evaporation of the stored liquid 86 by forming a vapor barrier between the stored liquid 86 and the atmosphere of the tank 78.
The modular barrier 94A, 94B, 94C may comprise a plurality of objects 102. In some embodiments, each object of the plurality of objects 102 is smaller than the access port 106 of the tank such that the plurality of objects 102 may be inserted into the tank 78 and removed from the tank 78 via the access port 106. For example, a diameter of each object of the plurality of objects 102 may be between 5″ to 7 ¾″. In other embodiments, the diameter of each object may be less than 5″ or greater than 7 ¾″. When the plurality of objects 102 are inserted into the tank 78, the plurality of objects 102 align next to each other so as to form the barrier 94A, 94B, 94C. The barrier 94A, 94B, 94C is also self-adjusting in that the plurality of objects 102 may also conform to a shape and size of the tank 78. The plurality of objects 102 may form one layer to form a barrier 94C, as shown, for example, in
Turning to
In some embodiments, the plurality of objects 102 comprises individual, unconnected objects. In other embodiments, the plurality of objects may comprise objects 102 connected to each other (via a tether or magnets, for example). The plurality of objects 102 are inserted into the tank until enough objects to cover the stored liquid 86 are inserted. As the surface of the liquid 86 is covered with the objects, the objects will contact each other until movement of an adjacent object is limited or restricted. As such, the plurality of objects 102 may conform to the shape of the tank 78 and form the modular barrier 94A, 94B, 94C. In some embodiments, the objects may also form multiple layers as shown in
As shown in
Similarly, as shown in
Similarly, as shown in
Turning to
It will be appreciated that though spheres, hexagonal prisms, dodecagons or other shapes are described above, that the modular barrier 94A, 94B, 94C may comprise a plurality of objects 102 of any shape or sizes. Further, in some embodiments, a modular barrier may comprise objects of different shapes. For example, the modular barrier 94A, 94B, 94C may comprise both hexagonal prisms, dodecahedrons, and/or spheres of different sizes (as illustrated in, for example,
In addition to covering the surface of the liquid, the modular barrier 94A, 94B, 94C can easily conform to different size tanks. To fill a larger tank, more objects (whether spheres, hexagonal prisms, dodecagons, or any object) are simply inserted into the tank until the surface of the liquid is substantially covered.
Turning to
The method also comprises covering the surface of the liquid with a modular barrier (step 508). The modular barrier may be the same as or similar to the modular barrier 94A, 94B, 94C. The modular barrier may comprise a plurality of objects such as the plurality of objects 102 operable to cover the upper surface of the liquid and conform to a shape of the storage tank when inserted into the enclosed volume.
While embodiments of the present invention are described with respect to oil storage tanks and hydrocarbon liquids, it will be appreciated that the present invention may be applied to a wider range of enclosed containers and contents of containers.
The invention has significant benefits across a broad spectrum of endeavors. It is the Applicant's intent that this specification and the claims appended hereto be accorded a breadth in keeping with the scope and spirit of the invention being disclosed despite what might appear to be limiting language imposed by the requirements of referring to the specific examples disclosed.
The phrases “at least one”, “one or more”, and “and/or”, as used herein, are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B, and C”, “at least one of A, B, or C”, “one or more of A, B, and C”, “one or more of A, B, or C,” and “A, B, and/or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B, and C together.
Unless otherwise indicated, all numbers expressing quantities, dimensions, conditions, and so forth used in the specification, drawings, and claims are to be understood as being modified in all instances by the term “about.”
The term “a” or “an” entity, as used herein, refers to one or more of that entity. As such, the terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein.
The use of “including,” “comprising,” or “having,” and variations thereof, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Accordingly, the terms “including,” “comprising,” or “having” and variations thereof can be used interchangeably herein.
It shall be understood that the term “means” as used herein shall be given its broadest possible interpretation in accordance with 35 U.S.C., Section 112(f). Accordingly, a claim incorporating the term “means” shall cover all structures, materials, or acts set forth herein, and all of the equivalents thereof. Further, the structures, materials, or acts, and the equivalents thereof, shall include all those described in the summary of the invention, brief description of the drawings, detailed description, abstract, and claims themselves.
The foregoing description of the invention has been presented for illustration and description purposes. However, the description is not intended to limit the invention to only the forms disclosed herein. In the foregoing Detailed Description for example, various features of the invention are grouped together in one or more embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate preferred embodiment of the invention.
Consequently, variations and modifications commensurate with the above teachings and skill and knowledge of the relevant art are within the scope of the invention. The embodiments described herein above are further intended to explain best modes of practicing the invention and to enable others skilled in the art to utilize the invention in such a manner, or include other embodiments with various modifications as required by the particular application(s) or use(s) of the invention. Thus, it is intended that the claims be construed to include alternative embodiments to the extent permitted by the prior art.
This application claims the benefit of U.S. Provisional Application No. 63/214,676, filed on Jun. 24, 2021 and entitled “MODULAR BARRIER FOR STORAGE TANKS,” which application is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63214676 | Jun 2021 | US |
