Patent Application
20230279994
The invention relates to container systems and related methods for the transportation and/or storage of liquefied natural gas (LNG).
Liquefied natural gas (LNG) is natural gas cooled down to its boiling point temperature of approximately -163° C. at atmospheric pressure to reach cryogenic liquid conditions. LNG is produced to enable the efficient storage and transport of natural gas. LNG is stored and transported in cryogenic containers. The LNG can be converted to natural gas by a process called regasification (vapourisation) and is typically used for fuel for domestic or industrial use and power generation.
A cryogenic container is a thermally-insulated container for storing or transporting liquefied gases at cryogenic temperatures. Depending upon the design of the container, the operating pressure can generally range from atmospheric to above 400 psia. Typically a cryogenic container includes an inner vessel for containing the cryogenic fluid, e.g. LNG, and an outer vessel for insulating the cryogenic fluid from the environment. The gap between the two vessels is at least partially evacuated to form a vacuum, which provides an insulating barrier and reduces the heat leakage into the cryogenic container from the ambient environment. To further reduce the heat leakage, heat reflective paints or insulation materials are also used. In certain cases, a superconductive layer comprising a material that is superconducting at the temperature of the cryogenic fluid is also used. This superconductive layer forms a magnetic field around the cryogenic container that repels electromagnetic energy, including thermal energy from the environment, keeping the cryogenic fluid at low temperatures. Other cryogenic container systems are also available for the transport of LNG. More recently, cryogenic ISO containers are being used to for storage of cryogenic fluids such as LNG. These containers are usually of standardized sizes ranging from cylinders of 8 feet in diameter and 10 to 40 feet in length.
Natural gas, for export as LNG, is sourced from an offshore or onshore natural gas field, a coal mine, a marine source, biogas facility or a diversion of flare-gas. The gas is delivered to a liquefaction plant (LNG plant) located on site or at the export port.
Background references include U.S. Pat. Nos, 6,212,891, 7,837,055; EP 2, 228 294 A; and WO 2000/57102.
ISO containers are starting to become a popular choice for the transport of LNG (virtual pipelines). Here, LNG is filled into a vacuum insulated ISO container and distributed by conventional transport mechanisms, such as, road or rail. These containers do not have any refrigeration systems connected to them, and the boiling methane results in an increase in the contained fluid pressure. Typical rating of these systems are around 350 psig, which results in thicker metal and increased cost. Furthermore, despite the higher pressure rating, there is a limit to how much LNG can be filled in these containers, as a function of anticipated shelf-life. A typical ISO container is expected to have a boil-off rate in the order of ~0.17% of the LNG per day. At this boil-off rate, the amount of LNG that can be stored and/or transported as a function of shelf-life is limited. Therefore, there exists a need for improved containers and related methods that can store and/or transport LNG.
In a class of embodiments, the invention provides for a container system for the transportation and/or storage of Liquefied Natural Gas (LNG), the container system comprising: a) an outer shell; b) an inner pressurized container, wherein the inner pressurized container comprises a first chamber having a first vent and at least one other chamber having a second vent; c) at least one heat exchange zone in thermal communication between the first chamber and the at least one other chamber; and d) an interstitial space between the outer shell and the inner pressurized container comprising at least a partial vacuum.
In another class of embodiments, the invention provides for a method for transporting and/or storing LNG comprising: a) filling the container system as described above with a primary fluid and sacrificial cryogenic fluid; b) sealing the container system; c) venting off a sacrificial gas to maintain a desired pressure of the inner pressurized container; and d) transporting and/or storing the LNG for at least 5 days without refilling the container system; wherein the inner pressurized container has a boil-off rate of < 0.20% of LNG per day.
Other embodiments of the invention are described and claimed herein and are apparent by the following disclosure.
Various terms are defined in the following Specification. A Glossary of terms is provided herein, immediately preceding the claims.
Before the present compounds, components, compositions, devices, softwares, hardwares, equipments, configurations, schematics, systems, and/or methods are disclosed and described, it is to be understood that unless otherwise indicated this invention is not limited to specific compounds, components, compositions, devices, softwares, hardwares, equipments, configurations, schematics, systems, methods, or the like, as such may vary, unless otherwise specified. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.
It must also be noted that, as used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless otherwise specified. Containers/Container Systems
In a class of embodiments, the invention provides for a container system for the transportation and/or storage of Liquefied Natural Gas (LNG), the container system comprising:
In these embodiments, a “sacrificial” cryogenic liquid is used to preferentially evaporate, while maintaining the LNG at low pressure and in liquid state. Examples of such sacrificial cryogenic liquids are liquid oxygen (LOX), liquid nitrogen (LIN), and liquid argon (LAR). It is expected that at an evaporation rate of 0.17%/day, a very small amount of sacrificial cryogenic fluid will be required, which re-liquefies the boil-off gas (~4% of the total weight for 30 day shelf-life). The sacrificial vapor gas may be vented. Additionally, by maintaining containers at lower pressures, a thinner and lighter container can be designed.
In another embodiment, an active mechanism, such as a pump, may be used to facilitate heat exchange, where the cryogenic sacrificial fluid (e.g., LIN) is pumped to exchange heat with the BOG and re-liquefy the gas. Finally, in yet another embodiment, a passive device 254, such as a heat pipe, can enable the necessary heat transfer between the cryogenic sacrificial fluid (e.g., LIN/cold nitrogen vapor) 251 on one side of the wall or barrier 250 and the BOG 252 on the other side to form a liquid 253 of the primary fluid, as shown in
In an alternative embodiment, the cryogenic sacrificial fluid (e.g., LIN) tank may be disposed directly on top of the primary fluid (e.g., LNG) tank or completely surrounding the primary fluid (e.g., LNG) tank. Without being bound to theory, these options may present a risk of freezing in the primary fluid (e.g.,LNG) but eliminates any risk of over pressure.
The ratio of the length of the outer shell to the length of the inner pressurized container is up to 0.99 and the ratio of the diameter of the outer shell to the diameter of the inner pressurized container is up to 0.99. In the alternative, the ratio of the length of the outer shell to the length of the inner pressurized container is up to 0.95 and the ratio of the diameter of the outer shell to the diameter of the inner pressurized container is up to 0.95. In yet another alternative, the ratio of the length of the outer shell to the length of the inner pressurized container is at least 0.80 and the ratio of the diameter of the outer shell to the diameter of the inner pressurized container is at least 0.80.
The volume percent of the first chamber is from 60 vol% to 90 vol% and the volume percent of the at least one other chamber is from 40 vol% to 10 vol%, based upon the total volume of the inner pressurized container. In the alternative, the volume percent of the first chamber is from 70 vol% to 95 vol% and the volume percent of the at least one other chamber is from 30 vol% to 5 vol%, based upon the total volume of the inner pressurized container. In yet another alternative, the volume percent of the first chamber is from 80 vol% to 97 vol% and the volume percent of the at least one other chamber is from 20 vol% to 3 vol%, based upon the total volume of the inner pressurized container.
The inner pressurized container may comprise at least one wall having a thickness and the thickness of the wall may be 3% thinner than a wall of a container of substantially the same capacity having only one chamber. In the alternative, the inner pressurized container may comprise at least one wall having a thickness and the thickness of the wall may be 5% thinner than a wall of a container of substantially the same capacity having only one chamber. In yet another alternative, the inner pressurized container may comprise at least one wall having a thickness and the thickness of the wall may be 10 % thinner than a wall of a container of substantially the same capacity having only one chamber.
In any of the embodiments described herein, the first chamber of the inner pressurized container may be filled to > 89 vol% with LNG for up to 10 days of storage and/or transportation, without cargo removal, to > 80 vol% with LNG for up to 20 days of storage and/or transportation, without cargo removal, or to > 79 vol% with LNG for up to 30 days of storage and/or transportation, without cargo removal.
In any of the embodiments described herein, the first chamber and the at least one other chamber may comprise different liquefied gases. For example, the first chamber may comprises LNG and at least one other chamber may comprise one or more of nitrogen, argon, or oxygen in a substantially liquid form.
In any of the embodiments described herein, the inner pressurized container may have a boil-off rate of < 0.20% of LNG per day, a boil-off rate of < 0.10% of LNG per day, or a boil-off rate of < 0.05% of LNG per day.
In any of the embodiments described above, the first chamber may be a first tank and the at least one other chamber may be a second tank. In certain embodiments, the first tank may be disposed in the second tank or the first tank may be disposed below the second tank.
In another class of embodiments, the invention provides for a method for transporting and/or storing Liquefied Natural Gas (LNG) comprising:
In these embodiments, the first chamber of the inner pressurized container may be filled to > 89 vol% with LNG for up to 10 days of storage and/or transportation, without cargo removal or to > 80 vol% with LNG for up to 20 days of storage and/or transportation, without cargo removal.
The container systems may comprise one or more liners. The liners may have relatively thin walls and typically do not have any load-bearing capability. The liners are constructed from substantially impermeable materials preferably having one or more of the following properties: toughness at cryogenic temperatures, tear resistance, low gas permeation rates, and mechanical integrity.
Substantially impermeable materials that may be utilized in constructing liners include, for example, at least one sheet of: a metallic foil, a synthetic polymer film, a metallic foil on a thin polymeric sheet or substrate, a metal-coated polymer substrate, or a laminate comprising a metallic liner sandwiched between polymeric layers. Suitable metallic foils include, for example, aluminum and stainless steel, preferably seamless. The primary purpose of the liner is to serve as a permeation barrier to the LNG cargo; and the liner need only have sufficient thickness to serve this purpose. Additionally, the liner should be sufficiently strong so that it can be handled without being torn.
In another embodiment, the liner may comprise at least one layer of a coating, for example, a substantially solid polyurethane formulation coating, applied to the inner wall. Such substantially solid polyurethane formulation coatings are commercially available and are currently applied as moisture barriers on the exterior of steel or composite tanks.
Containers typically have a standard cylindrical configuration but other shapes are suitable. Alternative geometric shapes for a container include a standard spherical shape, an oblate spheroid with varying aspect ratios; as well as the combinations of oblate spheroidal half domes attached to a relatively short cylindrical section. The flexibility of modem manufacturing processes allow for container configurations to be optimized for structural performance. For example, the spherical configuration for a steel container tends to optimize steel material usage; and, similarly, the oblate spheroid configuration tends to optimize composite material usage.
Containers may be insulated if desired. Several classes of compounds may be used as insulation. A group of foam materials such as polypropylene and polyethylene that meet strain and temperature and thermal conductivity requirements may be used in containers as insulation. Some conventional foams, such as polyurethane, may be used in a substantially noncompact form, for example, honeycomb core form sandwiched between layers of polyisocyanurate to provide an optimal-performing insulation laminate. Sprayable forms of polyisocyanurate and polyurethane may also be used for ease of application as well as moldable forms of polyurethane insulations.
As shown in
Glossary of terms:
The phrases, unless otherwise specified, “consists essentially of” and “consisting essentially of” do not exclude the presence of other steps, elements, or materials, whether or not, specifically mentioned in this specification, so long as such steps, elements, or materials, do not affect the basic and novel characteristics of the invention, additionally, they do not exclude impurities and variances normally associated with the elements and materials used.
For the sake of brevity, only certain ranges are explicitly disclosed herein. However, ranges from any lower limit may be combined with any upper limit to recite a range not explicitly recited, as well as, ranges from any lower limit may be combined with any other lower limit to recite a range not explicitly recited, in the same way, ranges from any upper limit may be combined with any other upper limit to recite a range not explicitly recited. Additionally, within a range includes every point or individual value between its end points even though not explicitly recited. Thus, every point or individual value may serve as its own lower or upper limit combined with any other point or individual value or any other lower or upper limit, to recite a range not explicitly recited.
All priority documents are herein fully incorporated by reference for all jurisdictions in which such incorporation is permitted and to the extent such disclosure is consistent with the description of the present invention. Further, all documents and references cited herein, including testing procedures, publications, patents, journal articles, etc. are herein fully incorporated by reference for all jurisdictions in which such incorporation is permitted and to the extent such disclosure is consistent with the description of the present invention.
While the invention has been described with respect to a number of embodiments and examples, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope and spirit of the invention as disclosed herein.
This application claims the priority benefit of U.S. Provisional Pat. Application No. 63/056779 filed Jul. 27, 2020, entitled CONTAINER SYSTEMS AND METHODS FOR USING THE SAME.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2021/070688 | 6/10/2021 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63056779 | Jul 2020 | US |
