Patent Description:
Various embodiments relate generally to the storage and transportation of compressed natural gas (CNG).

Gaseous fuels, such as natural gas, are typically transported by pipeline, although there are users of natural gas that periodically require natural gas supply in excess of the supply available through existing pipelines. In addition, there are areas in which natural gas service via pipeline is not available at all, due to remoteness, the high cost of laying pipelines, or other factors. For such areas, natural gas can be transported via CNG vessels, for example as described in <CIT>. <CIT> describes a movable transport for delivering natural gas, from a pipeline, by flowing the gas into multiple pressure vessels equipped with internal flexible bladders which will contain the gas until the pressure in the vessels equalizes with the pressure in the pipeline.

Natural gas is conventionally transported across waterways (e.g., rivers, lakes, gulfs, seas, oceans) in liquid natural gas (LNG) form. However, LNG requires complicated and expensive liquefaction plant and special handling on both the supply and delivery side. LNG also requires regasification upon delivery, which involves using substantial amounts of heat and complex cryogenic heat exchangers as well as cryogenic delivery/storage equipment.

The disclosure provides a cold compressed gas storage and transportation vehicle according to claim <NUM>. The compressed gas transportation vehicle includes: a vehicle; an insulated space supported by the vehicle; a compressed gas storage vessel that is at least partially disposed in the insulated space; and a carbon-dioxide-refrigerant-based refrigeration unit supported by the vehicle and configured to cool the insulated space.

The refrigeration unit is configured to maintain a temperature within the insulated space between -<NUM> and -<NUM> degrees C. According to one or more of these embodiments, the vehicle is a ship or a wheeled vehicle.

The refrigeration unit is configured to deposit solid carbon dioxide into the insulated space.

The refrigeration unit is configured to provide passive, sublimation-based cooling to the insulated space when solid carbon dioxide is in the insulated space, even when the refrigeration unit is off.

According to one embodiment, the vessel includes a gas port that fluidly connects to an upper portion of an interior volume of the vessel, and a hydraulic fluid port that fluidly connects to a lower portion of an interior volume of the vessel.

According to one or more of these embodiments, the vehicle is combined with a source facility that includes: a source of compressed gas configured to be fluidly connected to the gas port of the vehicle's vessel so as to deliver compressed gas to the vehicle's vessel, a hydraulic fluid reservoir configured to be fluidly connected to the hydraulic port of the vehicle's vessel by a hydraulic fluid passageway so as to facilitate the transfer of hydraulic fluid between the vehicle's vessel and the reservoir, and a pressure-actuated valve disposed in the hydraulic fluid passageway and configured to permit hydraulic fluid to flow from the vehicle's vessel to the source facility's hydraulic fluid reservoir when a pressure in the vehicle's vessel exceeds a predetermined pressure as compressed gas flows from the source of compressed gas into the vehicle's vessel.

The disclosure provides a method for transporting cold compressed gas, the method including: storing compressed gas in a storage vessel that is inside an insulated space of a vehicle; refrigerating the insulated space using a carbon-dioxide-based refrigeration unit; and moving the vehicle toward a destination facility.

The compressed gas may include compressed natural gas.

Refrigerating the insulated space includes depositing solid carbon dioxide in the insulated space.

Said moving may include moving the vehicle from a first geographic site to a second geographic site, and wherein a temperature within the insulated space remains between -<NUM> and -<NUM> degrees C throughout said moving.

The disclosure provides a method of loading compressed gas into a vessel containing a hydraulic fluid, the method including: loading compressed gas into the vessel by (<NUM>) injecting the compressed gas into the vessel and (<NUM>) removing hydraulic fluid from the vessel, wherein, throughout said loading, a pressure within the vessel remains within <NUM>% of a certain psig pressure.

Throughout said loading, the pressure within the vessel may remain within <NUM> psi of the certain psig pressure.

The certain pressure may be at least <NUM> psig.

At least a portion of said injecting may occur during at least a portion of said removing.

The hydraulic fluid may be a silicone- based fluid.

Throughout said loading, a temperature in the vessel may remain within <NUM> degrees C of -<NUM> degrees C.

A hydraulic fluid volume in the vessel before said loading may exceed a hydraulic fluid volume in the vessel after said loading by least <NUM>% of an internal volume of the vessel.

The method may also include: after said loading, unloading the vessel by (<NUM>) injecting hydraulic fluid into the vessel and (<NUM>) removing compressed gas from the vessel, wherein during said unloading the pressure within the vessel remains within <NUM>% of the certain psig pressure.

Throughout said unloading, a temperature of the vessel may remain within <NUM> degrees C of -<NUM> degrees C.

A hydraulic fluid volume in the vessel after said unloading may exceed a hydraulic fluid volume in the vessel before said unloading by least <NUM>% of the internal volume of the vessel.

The method may also include: cyclically repeating said loading and unloading at least <NUM> more times, wherein throughout said cyclical repeating, the pressure within the vessel remains within <NUM>% of the certain psig pressure.

The vessel is supported by a vehicle, the loading may occur at a first geographic site, and the unloading occurs at a second geographic site that is different than the first geographic site.

The compressed gas storage and transportation vehicle additionally includes: a hydraulic fluid reservoir supported by the vessel; a passageway connecting the hydraulic fluid reservoir to the compressed gas storage vessel; and a pump disposed in the passageway and configured to selectively pump hydraulic fluid through the passageway from the reservoir into the compressed gas storage vessel.

The compressed gas storage vessel may include a plurality of pressure vessels, and the reservoir may at least partially disposed in an interstitial space between the plurality of pressure vessels.

According to one or more of these embodiments, the vehicle is a ship, a locomotive, or a locomotive tender.

The combination also includes, an insulated space supported by the vehicle. The vessel and preferably also the reservoir are disposed in the insulated space, and a carbon-dioxide-refrigerant-based refrigeration unit supported by the vehicle and configured to cool the insulated space.

The disclosure provides a method of transferring compressed gas, the method including: loading compressed gas into a vessel at a first geographic site; after said loading, moving the vessel to a second geographic site that is different than the first geographic site; unloading compressed gas from the vessel at the second geographic site; loading compressed nitrogen into the vessel at the second geographic site; after said unloading and loading at the second geographic site, moving the vessel to a third geographic site; and unloading nitrogen from the vessel at the third geographic site, wherein, throughout the loading of compressed gas and nitrogen into the vessel, moving of the vessel to the second and third geographic sites, and unloading of the compressed gas and nitrogen from the vessel, a pressure within the vessel remains within <NUM>% of a certain psig pressure.

The first geographic site may be the third geographic site.

The method may also include repeating these loading and unloading steps while the pressure within the vessel remains within <NUM>% of the certain psig pressure.

The disclosure also provides a vessel for storing compressed gas, the vessel including: a fluid-tight liner defining therein an interior volume of the vessel; at least one port in fluid communication with the interior volume; carbon fiber wrapped around the liner; and fiber glass wrapped around the liner.

The interior volume may be generally cylinder shaped with bulging ends. An outer diameter of the vessel may be at least three feet.

The interior volume may be at least <NUM>,<NUM> liters.

A ratio of a length of the vessel to an outer diameter of the vessel may be at least <NUM>: <NUM>.

A ratio of a length of the vessel to an outer diameter of the vessel may be less than <NUM>: <NUM>.

The carbon fiber may be wrapped around the liner along a path that strengthens a weakest portion of the liner, in view of a shape of the interior volume.

The carbon fiber may be wrapped diagonally around the liner relative to longitudinal axis of the vessel that is concentric with the cylinder shape.

The liner may include ultra-high molecular weight polyethylene.

The carbon fiber may be wrapped in selective locations around the liner such that the carbon fiber does not form a nonhomogeneous/discontinuous layer around the liner.

The fiber glass may be wrapped around the liner so as to form a continuous layer around the liner.

The vessel also may include a plurality of longitudinally-spaced reinforcement hoops disposed outside the liner.

The vessel may also include a plurality of tensile structures extending longitudinally between two of said plurality of longitudinally-spaced reinforcement hoops, wherein said plurality of tensile structures are circumferentially spaced from each other.

The at least one port may include a first port; the vessel further includes: a first dip tube inside the interior volume and in fluid communication with the first port, the first dip tube having a first opening that is in fluid communication with the interior volume, the first opening being disposed in a lower portion of the interior volume; and a first impingement deflector disposed in the interior volume between the first opening and an interior surface of the liner, the first impingement deflector being positioned so as to discourage substances that enter the interior volume via the first dip tube from forcefully impinging on the interior surface of the liner.

The at least one port may include a second port, and the vessel further includes: a second dip tube inside the interior volume and in fluid communication with the second port, the second dip tube having a second opening that is in fluid communication with the interior volume, the second opening being disposed in an upper portion of the interior volume, and a second impingement deflector disposed in the interior volume between the second opening and the interior surface of the liner, the second impingement deflector being positioned so as to discourage substances that enter the interior volume via the second dip tube from forcefully impinging on the interior surface of the liner.

The disclosure provides a vessel for storing compressed gas, the vessel including: a fluid-tight vessel having an interior surface that forms an interior volume; a first port in fluid communication with the interior volume; a first dip tube inside the interior volume and in fluid communication with the first port, the first dip tube having a first opening that is in fluid communication with the interior volume, the first opening being disposed in one of a lower or upper portion of the interior volume; and a first impingement deflector disposed in the interior volume between the first opening and the interior surface, the first impingement deflector being positioned so as to discourage substances that enter the interior volume via the first dip tube from forcefully impinging on the interior surface of the liner.

The first opening may be disposed in the lower portion of the interior volume; and the vessel further includes: a second port in fluid communication with the interior volume; a second dip tube inside the interior volume and in fluid communication with the second port, the second dip tube having a second opening that is in fluid communication with the interior volume, the second opening being disposed in an upper portion of the interior volume; and a second impingement deflector disposed in the interior volume between the second opening and the interior surface, the second impingement deflector being positioned so as to discourage substances that enter the interior volume via the second dip tube from forcefully impinging on the interior surface.

The disclosure provides a combination that includes: a pressure vessel forming an interior volume; a first passageway fluidly connecting the interior volume to a port; a normally-open, sensor-controlled valve disposed in the passageway, the valve having a sensor; a second passageway connecting the interior volume to a vent; and a burst object disposed in and blocking the second passageway so as to prevent passage of fluid from the interior volume to the vent, the burst object being exposed to the pressure within the interior volume and having a lower failure-resistance to such pressure than the pressure vessel, wherein the burst object is positioned and configured such that a pressure-induced failure of the burst object would unblock the second passageway and cause pressurized fluid in the interior volume to vent from the interior volume to the vent via the second passageway, wherein the sensor is operatively connected to the second passageway between the burst object and the vent and is configured to sense flow of fluid resulting from a failure of the burst object and responsively close the valve.

One or more of these and/or other aspects of various embodiments, as well as the methods of operation and functions of the related elements of structure and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. In one embodiment, the structural components illustrated herein are drawn to scale. In addition, it should be appreciated that structural features shown or described in any one embodiment herein can be used in other embodiments as well. As used in the specification and in the claims, the singular form of "a", "an", and "the" include plural referents unless the context clearly dictates otherwise.

All closed-ended (e.g., between A and B) and open-ended (greater than C) ranges of values disclosed herein explicitly include all ranges that fall within or nest within such ranges. For example, a disclosed range of <NUM>-<NUM> is understood as also disclosing, among other ranges, <NUM>- <NUM>, <NUM>-<NUM>, <NUM>-<NUM>, etc..

For a better understanding of various embodiments as well as other objects and further features thereof, reference is made to the following description which is to be used in conjunction with the accompanying drawings, where:.

<FIG> diagrammatically illustrate a CNG transportation system <NUM> according to one or more embodiments. The system includes a source facility <NUM> (see <FIG>), a vehicle <NUM>, and a destination facility <NUM> (see <FIG>). The source and destination facilities <NUM>, <NUM> are at different geographic sites (e.g., which are separated from each other by at least <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM> miles).

As shown in <FIG>, the source facility <NUM> receives a supply of natural gas from a natural gas source <NUM> (a natural gas pipeline; a wellhead; a diverter from a flare gas passage (e.g., of an oil well or platform or other facility where gas might otherwise be flared); a source of biogas (e.g., a digester or landfill); a gas processing and conditioning system where lean gas is used onsite and richer gas might otherwise be flared; a source that provides NGLs condensed from rich gas when lean gas would otherwise be flared; etc.). A passageway <NUM> extends from the source <NUM> to an inlet of a dryer <NUM>. An outlet of the dryer <NUM> connects to the inlet(s) of one or more parallel or serial compressors <NUM> via a passageway <NUM>. A passageway <NUM> connects the outlet(s) of the compressor(s) <NUM> to a gas port/connector 120a of a cold storage unit <NUM>. The passageway <NUM> also connects to a discharge port/connector <NUM> of the source facility <NUM>. A bypass passageway <NUM> bypasses the compressor(s) <NUM> so as to connect the source <NUM> directly to the passageway <NUM>. The bypass passageway <NUM> may be used to conserve energy and avoid excess compressor <NUM> use when upstream pressure from the source <NUM> is sufficiently high without compression.

An active cooling system <NUM> cools natural gas passing through the passageway <NUM>, preferably to a cold storage temperature range. An active cooling system <NUM> maintains the vessels <NUM> of the cold storage unit <NUM> within the desired cold storage temperature range. According to various embodiments, the cooling system <NUM>, <NUM> may utilize any suitable cooling technology (e.g., the CO<NUM> cooling cycle used by the below-discussed cooling system <NUM>). The system <NUM> may provide passive cooling via CO<NUM> sublimation in the same manner as described below with respect to the cooling system <NUM>. According to various embodiments, the cold storage range may be a temperature within <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM> of -<NUM> (i.e., the sea-level sublimation temperature of CO<NUM>). According to various embodiments, the cold storage temperature range extends as high as <NUM> for alternative passive or phase-change refrigerants such as paraffin waxes, among others.

As shown in <FIG>, the source facility <NUM> includes a hydraulic fluid reservoir <NUM> that connects to an inlet of a pump <NUM> via a passageway <NUM>. A pressure-controlled valve <NUM> is disposed in parallel with the pump <NUM>. A passageway <NUM> connects an outlet of the pump <NUM> to a hydraulic fluid port/connector 120b of the cold storage unit <NUM>.

As shown in <FIG>, a passageway <NUM> connects the hydraulic fluid reservoir <NUM> to an inlet of a vapor recovery unit (VRU) compressor <NUM>. An outlet of the compressor <NUM> connects to the passageway <NUM>. The compressor <NUM> collects and recirculates dissolved gas that can come out of solution with the hydraulic fluid in the reservoir <NUM> (particularly if the reservoir <NUM> is depressurized).

According to various embodiments, the compressor <NUM> is enclosed so that gas leaking from the compressors <NUM>, which would otherwise leak into the ambient environment, is collected and returned to the VRU compressor <NUM> via a passageway <NUM> to be recirculated into the system.

As shown in <FIG>, a passageway <NUM> connects the hydraulic fluid reservoir <NUM> to an inlet of a pump <NUM> and an outlet of a pressure-controlled valve <NUM>. A passageway <NUM> connects an outlet of the pump <NUM> to an inlet of the valve <NUM> and a hydraulic fluid port/connector <NUM>.

The source facility <NUM> may comprise a land-based facility with a fixed geographic location (e.g., at a port, along a CNG gas supply pipeline, at a rail hub). Alternatively, the source facility <NUM> may itself be supported by a vehicle (e.g., a wheeled trailer, a rail vehicle (e.g., a locomotive, locomotive tender, box car, freight car, tank car), a floating vessel such as a barge or ship) to facilitate movement of the source facility <NUM> to different gas sources <NUM> (e.g., a series of wellheads). Although the illustrated embodiments show a single offtake point between the source facility <NUM> and one vehicle <NUM>, the source facility <NUM> may include multiple offtake points along a pipeline so as to facilitate the simultaneous filling of multiple vehicles <NUM> or other vessels with gas.

As shown in <FIG>, the vehicle <NUM> may be any type of movable vehicle, e.g., a barge, a ship, a wheeled trailer, rail car(s). The vehicle <NUM> includes a gas port/connector <NUM> that is configured to detachably connect to the port/connector <NUM> of the source facility <NUM>. A passageway <NUM> connects the port/connector <NUM> to a gas port 320a of a cold storage unit <NUM> of the vehicle <NUM>. A pressure-controlled valve <NUM> is disposed in the passageway <NUM>. A hydraulic fluid port 320b of the cold storage unit <NUM> connects, via a passageway <NUM>, to a hydraulic fluid connector/port <NUM> of the vehicle <NUM>. The hydraulic fluid connector/port <NUM> is configured to detachably connect to the port/connector <NUM> of the source facility <NUM>.

As shown in <FIG>, each of the cold storage units <NUM>, <NUM>, <NUM> of the source facility <NUM>, vehicle <NUM>, and/or destination facility <NUM> may be structurally and/or functionally similar or identical to each other. The units <NUM>, <NUM>, <NUM> include one or more parallel storage/pressure vessels <NUM>. The vessel(s) <NUM> are illustrated as a single vessel <NUM> in <FIG>, but are illustrated as multiple parallel vessels <NUM> in <FIG> and <FIG>. As shown in <FIG>, an upper portion of an interior storage volume 400a of the vessel <NUM> fluidly connects to the gas port 120a, 320a, 520a of the unit <NUM>, <NUM>, <NUM>. A lower portion of the interior storage volume 400a of the vessel fluidly connects to the hydraulic fluid port 120b, 320b, 520b of the unit <NUM>, <NUM>, <NUM>. As illustrated in <FIG>, the hydraulic fluid port 120b, 320b connects to the lower portion of the volume 400a via a dip tube passageway <NUM> that extends through the port 120a, 320a down to a lower portion of the interior volume 400a. Alternatively, as shown with respect to the unit <NUM> in <FIG>, the port 120b, 320b, 520b may connect be directly formed in a lower (e.g., bottom) of the vessel <NUM> so as to be connected to a lower portion of the interior 400a of the vessel <NUM>.

The vessel(s) of each unit <NUM>, <NUM>, <NUM> are housed within an insulated, sealed space <NUM>, which may be formed by any suitable insulator or combination of insulators (e.g., foam, plastics, inert gas spaces, vacuum spaces, etc.). In the case of a land-based unit (e.g., the unit <NUM> according to various embodiments of the source facility <NUM>), a portion of the space <NUM> may be formed by concrete walls.

As shown in <FIG>, the insulated space <NUM> and vessels <NUM> are kept cold by a refrigeration system <NUM> the preferably maintains the vessels <NUM> within a cold storage temperature range (e.g., a temperature within <NUM>, <NUM>, <NUM>, and/or <NUM> of -<NUM> (i.e., the sublimation temperature of CO<NUM>)). The illustrated refrigeration system <NUM> comprises a CO<NUM> refrigeration system that forms and deposits solid CO<NUM> <NUM> in the space <NUM>. The system <NUM> works as follows. Gaseous CO<NUM> is drawn from the space <NUM> into an inlet 440a of a passageway <NUM> that flows sequentially through a heat exchanger <NUM>, a compressor <NUM> that compresses the CO<NUM> gas, a heat exchanger <NUM> that dumps heat from the CO<NUM> gas into an ambient environment, an active conventional cooling system <NUM> that draws heat from the CO<NUM> gas via a conventional refrigerant (e.g., Freon, HFA) or other cooling system and liquefies the pressurized CO<NUM>, the heat exchanger <NUM>, a pressure-controlled valve <NUM>, and an outlet 440b of the passageway. According to various non-limiting embodiments, the expansion cooling is sufficient that the cooling system <NUM> may be sometimes turned off or eliminated altogether. Passage of the pressurized liquid CO<NUM> through the valve <NUM> and outlet 440b quickly depressurizes the CO<NUM>, causing it to solidify into solid CO<NUM> <NUM> that at least partially fills the space <NUM>, until it sublimates and reenters the inlet 440a. The solid CO<NUM> <NUM> tends to keep the space <NUM> and vessels <NUM> at about -<NUM> (i.e., the sublimation temperature of CO<NUM> at ambient pressure/sea level).

The use of a solid CO<NUM> refrigeration systems <NUM>, <NUM>, <NUM> offers various benefits, according to various non-limiting embodiments. For example, the accumulated solid CO<NUM> <NUM> in the space <NUM> can provide passive cooling for the vessels <NUM> if the active system <NUM> temporarily fails. The passive solid CO<NUM> cooling can provide time to fix the system <NUM> and/or to offload CNG from the vessels <NUM> if the vessels <NUM> are ill-equipped to handle their existing CNG loading at a higher temperature. Solid CO<NUM> refrigeration systems <NUM>, <NUM>, <NUM> tend to be simple and inexpensive, especially when compared to other refrigeration systems that achieve similar temperatures.

Solid CO<NUM> refrigeration systems <NUM>, <NUM>, <NUM> are particularly well suited for maintaining the space <NUM> at a relatively constant temperature, i.e., the -<NUM> sublimation temperature of CO<NUM>. The relatively constant temperature of the space <NUM> tends to discourage the vessel(s) <NUM> from changing temperature, which, in turn, tends to discourage large pressure changes within the vessel(s) <NUM>, which reduces fatigue stresses on the vessel(s) <NUM>, which can extend the useful life of the vessel(s) <NUM>.

According to one or more non-limiting embodiments, the natural storage temperature of a CO<NUM> cooling system <NUM>, <NUM>, <NUM> (e.g., at or around -<NUM>) offers one or more benefits. First, CNG is quite dense at such temperatures and the operating pressures used by the vessels <NUM>. For example, at <NUM> psig and -<NUM>, CNG's density is about <NUM>/m<NUM>, which approaches the effective/practical density of liquid natural gas (LNG) at <NUM> psig, particularly when one accounts for (<NUM>) the required vapor head room/empty space required for LNG storage, and/or (<NUM>) the heel amount of LNG that is used to maintain an LNG vessel at a cold temperature to prevent thermal shocks). This makes CNG competitive with LNG from a mass/volume basis, particularly in view of the more complicated handling and liquefaction procedures required for LNG. Second, although -<NUM> is cold, a variety of cheap, readily-available materials can handle such temperatures and may be used for the various components of the system <NUM> (e.g., valves, passageways, vessels, pumps, compressors, etc.). For example, low-nickel content steel (e.g. <NUM>%) can be used at such temperatures. In contrast, more expensive, higher-nickel content steels (e.g., <NUM>+%) are typically used at the lower temperatures associated with LNG. Third, a variety of cheap, readily available hydraulic fluids <NUM> (e.g., silicone-based fluids) for use in the system <NUM> remain liquid and relatively non-viscous at or around -<NUM>. In contrast, typical hydraulic fluids are not feasibly liquid and non-viscous at the typical operating temperatures of LNG systems. Fourth, according to various non-limiting embodiments, the CO<NUM> temperature range of the system <NUM>, <NUM>, <NUM> can avoid the need for more expensive equipment that could be required at lower operating temperatures.

According to various non-limiting embodiments, a CO<NUM> cooling system <NUM>, <NUM> provides fire suppression benefits as well by generally encasing the vessels <NUM> in a fire-retardant volume of CO<NUM>. CO<NUM> is heavier than oxygen, so the CO<NUM> layer will tend to stay around the vessels <NUM> and displace oxygen upward and out of the space <NUM>. For example, in a ship embodiment of the vehicle <NUM> in which walls within or of a cargo hold of the ship <NUM> forms the insulated space <NUM>, the space <NUM> will naturally tend to fill with heavier-than-air CO<NUM>, which will tend to suppress fires in the space <NUM>.

According to various embodiments, the hydraulic fluid is preferably a generally incompressible fluid such as a liquid.

The illustrated refrigeration systems <NUM>, <NUM>, <NUM> are based on solid CO<NUM> refrigeration cycles. However, any other type of refrigeration system may alternatively be used for the systems <NUM>, <NUM>, <NUM> without deviating from the scope of the present invention (e.g., cascade systems that depend on multiple refrigerant loops; a refrigeration system that utilizes a different refrigerant (e.g., paraffin wax)). For example, other low expansion coefficient passive heat exchange systems could be used such as paraffin waxes, which change phase from liquid to solid for example at -20C and have a high thermal mass. Such systems may provide passive cooling. Moreover, the refrigeration systems <NUM>, <NUM>, <NUM> may be eliminated altogether without deviating from the scope of the invention, e.g., in the case of embodiments that rely on warmer (e.g., ambient) CNG storage units, rather than the illustrated cold storage units.

Hereinafter, transfer of CNG from the source <NUM> to the source facility cold storage unit <NUM> is described with reference to <FIG>. When the vessels <NUM> of the storage unit <NUM> do not contain CNG, they are filled with pressurized hydraulic fluid and maintained at a desired pressure. To fill the unit <NUM> with CNG, CNG from the source <NUM> flows through the passageway <NUM>, dryer <NUM>, and passageway <NUM> to the compressor(s) <NUM>. The compressors <NUM> compress the CNG. This compression tends to heat the CNG, so the cooling system <NUM> cools the compressed CNG to a desired temperature (e.g., around -<NUM>). Cold CNG then travels through the remainder of the passageway <NUM> to the port 120a and vessels <NUM>. The filling of the vessels <NUM> of the unit <NUM> with CNG displaces hydraulic fluid downwardly and out of the vessels <NUM> via the hydraulic fluid port 120b. The displaced hydraulic fluid empties into the reservoir <NUM> via the passageways <NUM>, <NUM> and pressure-controlled valve <NUM>. The pressure-controlled valve <NUM> only permits hydraulic fluid to flow out of the vessels <NUM> when the vessel <NUM> pressure (e.g., as sensed by the valve <NUM> in the passageway <NUM>) exceeds a predetermined value (e.g., at or slightly above a desired vessel <NUM> pressure).

Hereinafter, the transfer of CNG from the source facility <NUM> to the vehicle <NUM> is described with reference to <FIG>. The connector <NUM> is attached to the connector <NUM>, and the connector <NUM> is attached to the connector <NUM>. The vessels <NUM> of the unit <NUM> are full of pressurized hydraulic fluid so that the vessels <NUM> are maintained at or around a desired pressure. The unit <NUM> can be filled with CNG from the unit <NUM> and/or directly from the source <NUM>. With respect to CNG delivery directly from the source <NUM>, CNG from the source <NUM> proceeds to the unit <NUM> in the same manner as described above with respect to the filling of the unit <NUM>, except that the CNG continues on through the passage <NUM> across the connectors <NUM>, <NUM>, through the passageway <NUM>, and to the pressure-controlled valve <NUM>. CNG can simultaneously or alternatively be delivered to the vehicle <NUM> from the unit <NUM>. To do so, the pump <NUM> delivers pressurized hydraulic fluid to the vessels <NUM> of the unit <NUM>, which displaced CNG out through the port 120a, through the passageway <NUM>, across the connectors <NUM>, <NUM>, through the passageway <NUM>, and to the pressure-controlled valve <NUM>. When CNG pressure in the passageway <NUM> exceeds a set point of the valve <NUM> (e.g., a set point at or above the desired pressure of the vessels <NUM> of the unit <NUM>), the valve <NUM> opens, which causes cold CNG to flow into the vessels <NUM> of the unit <NUM> of the vehicle <NUM>. This flow of CNG into the unit <NUM> displaces hydraulic fluid out of the vessels <NUM> of the unit <NUM> through the port 320b, passageway <NUM>, connectors <NUM>, <NUM>, passageway <NUM> and to the pressure-controlled valve <NUM>. When the pressure in the passageway <NUM> exceeds a set point of the valve <NUM> (e.g., a set point at, near, or slightly below the desired pressure of the vessels <NUM> of the unit <NUM>), the valve <NUM> opens to allow hydraulic fluid to flow through the passageway <NUM> into the reservoir <NUM>. When the vessels <NUM> of the unit <NUM> have been filled with CNG, the appropriate valves are shut off, the connectors <NUM> and <NUM> are disconnected from the connectors <NUM>, <NUM>, respectively, and the vehicle <NUM> can travel to its destination facility <NUM>. According to various embodiments, liquid sensor(s) may be disposed in the various passageways and/or at the upper/top and lower/bottom of the vessels <NUM> so as to indicate when the vessels <NUM> have been emptied or filled with CNG or hydraulic fluid. Such liquid sensors may be configured to trigger close the associated gas/hydraulic fluid transfer valves to stop the process once the process has been completed.

The use of the storage buffer created by the cold storage unit <NUM> may facilitate the use of smaller, cheaper compressor(s) <NUM> and/or faster vehicle <NUM> filling than would be appropriate in the absence of the unit <NUM>. This may reduce the vehicle <NUM>'s idle time and increase the time during which the vehicle <NUM> is being actively used to transport gas (e.g., obtaining better utilization from each vehicle <NUM>). Small compressors <NUM> may continuously run to continuously fill the unit <NUM> with CNG at the desired pressure and temperature, even when a vehicle <NUM> is not available for filling. In that manner, the compressors <NUM> do not have to compress all CNG to be delivered to a vehicle <NUM> while the vehicle <NUM> is docked with the source facility <NUM>. Real-time direct transfer from a low-pressure source <NUM> to a vehicle <NUM> without the use of the buffer unit <NUM> would require larger, more expensive compressors <NUM> and/or a significantly longer time to fill the unit <NUM> of the vehicle <NUM>.

Hereinafter, the structural components of non-limiting examples of the destination facility <NUM> are described with reference to <FIG>. A gas delivery connector <NUM> connects to a gas delivery passageway <NUM>, which, in turn, connects to one or more intermediate or end CNG destinations, including, for example, a gas port 520a of a destination buffer cold storage unit <NUM>, a CNG power generator <NUM>, a filling station <NUM> for CNG-powered vehicles, a filling station <NUM> for CNG trailers <NUM> (which may be of the type described in <CIT> : <NUM>), and/or an LNG production and distribution plant <NUM> for LNG trailers <NUM>, a delivery passageway <NUM> to a low-pressure CNG pipeline disposed downstream from an expander <NUM> of the LNG plant <NUM>, among other destinations.

According to various non-limiting embodiments, the CNG power generator <NUM> may comprise a gas turbine that could have power and efficiency augmentation in a warm humid climate by using the cold expanded natural gas to cool the inlet air and also extract humidity. If a desiccant dehydration system is to be used, waste heat from the turbine of the generator <NUM> (e.g., exhaust from a simple cycle turbine or the condensing steam after the bottoming cycle in CCGT) can be used (e.g., to heat the gas flowing through the passageway <NUM> to any destination user of gas).

According to various non-limiting embodiments, the LNG plant <NUM> may use a crossflow heat exchanger and supporting systems to use the expansion-cooling to generate LNG without an additional parasitic energy load, for example.

As shown in <FIG>, the destination facility includes a hydraulic fluid connector <NUM> that detachably connects to the connector <NUM> of the vehicle <NUM>. A passageway <NUM> connects the connector <NUM> to a hydraulic fluid reservoir <NUM>. Two pumps <NUM>, <NUM> and a pressure-controlled valve <NUM> are disposed in parallel to each other in the passageway <NUM>.

The pump <NUM> may be a reversible pump (e.g., a closed loop pump) that can absorb energy from the pressure letdown (e.g., when hydraulic fluid is transferred from the vessel <NUM> of the vehicle <NUM> to the reservoir <NUM>, which can occur, for example, when a nitrogen ballast system is used, as explained below). The valve <NUM> may be used to control the pressure in the vessel <NUM> of the vehicle <NUM> by permitting hydraulic fluid to flow back into the reservoir <NUM> when the valve <NUM> senses that a pressure in the vessel <NUM> exceeds a predetermined value.

As shown in <FIG>, a hydraulic fluid port/connector 520b of the cold storage unit <NUM> connects to the hydraulic fluid reservoir <NUM> via a passageway <NUM>. A pump <NUM> and pressure-controlled valve <NUM> are disposed in parallel with each other in the passageway <NUM>.

According to various embodiments, the buffer cold storage unit <NUM> provides CNG to the various destination users <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> when CNG is not being provided directly from a vehicle <NUM>. The pressure within the vessels <NUM> of the unit <NUM> is monitored by pressure sensors. When the sensed pressure within the vessel(s) <NUM> of the unit <NUM> deviates from a desired pressure by more than a predetermined amount (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or more psi; <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and/or more % of the desired pressure (in psig terms)), the pump <NUM> pumps hydraulic fluid from the reservoir <NUM> into the vessels <NUM> of the unit <NUM> so as to maintain a pressure within the vessels <NUM> of the unit <NUM> to consistently stay within a desired pressure range. Thus, pressurized hydraulic fluid displaces the CNG being depleted from the vessels <NUM> of the unit <NUM>.

Hereinafter, delivery of CNG from the vehicle <NUM> to the destination facility <NUM> is described with reference to <FIG>. When the vehicle <NUM> arrives at the destination facility <NUM>, the vessels <NUM> of the destination cold storage unit <NUM> typically partially or fully filled with hydraulic fluid. The vehicle <NUM> docks with the destination facility <NUM> by connecting the connector <NUM> to the connector <NUM> and by connecting the connector <NUM> to the connector <NUM>. The pump <NUM> pumps hydraulic fluid from the reservoir <NUM> into the vessels <NUM> of the unit <NUM> of the vehicle <NUM> (see <FIG> for details), which forces CNG out of the vessels <NUM> of the unit <NUM> of the vehicle <NUM>, through the connectors <NUM>, <NUM>, and into the passageway <NUM>, where CNG is delivered to the buffer storage unit <NUM> and/or one or more of the above-discussed destinations <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. The pressure controlled valve <NUM> of the vehicle <NUM> (see <FIG>), may only allow CNG to transfer from the vehicle <NUM> to the destination facility <NUM> when a pressure in the vessels <NUM> of the unit <NUM> exceeds a predetermined threshold (e.g., at or above the designed operating pressure of the vessels <NUM> of the unit <NUM>). In this way, a pressure within the vessels <NUM> of the unit <NUM> is consistently maintained at or near a desired pressure.

As shown in <FIG>, a variety of additional valves <NUM> (not all shown) are disposed throughout the passageways of the source facility <NUM>, vehicle <NUM>, and destination facility <NUM>. These valves <NUM> are opened and closed as desired (e.g., manually or automatically (e.g., pressure-controlled valves))to facilitate fluid (e.g., CNG, hydraulic fluid) flow along the desired pathways and/or to prevent fluid flow along non-desired pathways for particular operating conditions (e.g., filling the unit <NUM> with CNG from the source <NUM>; filling the unit <NUM> with CNG from the source facility <NUM>; transferring CNG from the unit <NUM> to the destination facility <NUM>).

The transfer of CNG and/or hydraulic fluid between the various facilities <NUM>, <NUM>, <NUM>, storage units <NUM>, <NUM>, <NUM>, vessels <NUM>, and destination users <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may be manual, or it may be partially or fully automated by one or more control systems. The control systems may include a variety of sensors (e.g., pressure, temperature, mass flow, etc.) that monitor conditions throughout or in various parts of the system <NUM>. Such control systems may responsively control the CNG/hydraulic fluid transfer process (e.g., by controlling the valves, pumps <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, compressors <NUM>, coolers <NUM>, <NUM>, <NUM>, heaters, etc.). Such control systems may be analog or digital, and may comprise computer systems programmed to carry out the above-discussed CNG transfer algorithms.

In the above-described system <NUM>, the hydraulic fluid reservoirs <NUM>, <NUM> are disposed at the source and destination facilities <NUM>, <NUM>. Use of the system <NUM> will gradually shift hydraulic fluid from the reservoir <NUM> at the destination facility <NUM> to the reservoir <NUM> at the source facility <NUM>. To account for such depletion, hydraulic fluid can periodically be transferred (e.g., via a vehicle) back from the reservoir <NUM> of the source facility <NUM> to the reservoir <NUM> of the destination facility.

According to one or more alternative embodiments, as illustrated in <FIG>, the system <NUM> is modified to replace the vehicle <NUM> with a vehicle <NUM>, which is generally similar to the vehicle <NUM>, so a redundant description of similar components is omitted. The vehicle <NUM> differs from the vehicle <NUM> by adding a vehicle-bom hydraulic fluid reservoir <NUM> that connects to the hydraulic fluid port 320b of the unit <NUM> via a passageway <NUM>. Two pumps <NUM>, <NUM> and a press-regulated valve <NUM> are disposed in parallel to each other in the passageway <NUM>. The reservoir <NUM> has sufficient capacity and hydraulic fluid to completely fill the vessels <NUM> of the unit <NUM>.

According to various embodiments, the hydraulic fluid reservoir <NUM> and/or other parts of the vehicle <NUM> (e.g., the passageway <NUM>, pumps <NUM>, <NUM>, and valve <NUM>) may be disposed within the cooled/insulated space <NUM> of the unit <NUM>. The reservoir <NUM> may be disposed in a vessels that is contoured to fit within interstitial spaces between the vessels <NUM> of the vehicle <NUM>. The refrigeration unit <NUM> may deposit solid CO<NUM> into spaces between and around the vessels <NUM>, reservoir <NUM>, and any other components that are disposed within the space <NUM> of the vehicle <NUM>.

During transfer of CNG from the source facility <NUM> to the vehicle <NUM>, the reservoir <NUM>, passageway <NUM>, and valve <NUM> work in the same manner as the above discussed reservoir <NUM>, passageways <NUM>, <NUM>, <NUM> and valve <NUM>. During transfer of CNG from the vehicle <NUM> to the destination facility <NUM>, the reservoir <NUM>, passageway <NUM>, and pump <NUM> work in the same manner as the above-described reservoir <NUM>, passageway <NUM>, and pump <NUM>. Use of the vehicle <NUM> avoids the repeating transfer of hydraulic fluid from the destination facility <NUM> to the source facility <NUM>.

As a result, the vehicle <NUM> travels from the source facility <NUM> to the destination facility <NUM> with hydraulic fluid disposed predominantly in the reservoir <NUM> and CNG in the vessels <NUM>. When the vehicle <NUM> travels to the source facility <NUM> from the destination facility <NUM>, the vessels <NUM> are filled with hydraulic fluid and the reservoir <NUM> may be predominantly empty.

<FIG> illustrates an alternative vehicle <NUM>, which is generally similar to the vehicle <NUM>, except as discussed below. Unlike with the cold storage unit <NUM> of the vehicles <NUM>, <NUM>, the vessels <NUM> of the vehicle <NUM> are not refrigerated, so the vessels <NUM> of the vehicle <NUM> may be at ambient temperatures. The hydraulic reservoir <NUM> of the vehicle <NUM> is formed in the interstitial spaces between and around the vessels <NUM> so that the hydraulic fluid <NUM> fills this interstitial space.

According to an alternative embodiment, the vessels <NUM> of the vehicle <NUM> are filled with compressed nitrogen at the destination facility <NUM>, so that nitrogen, rather than hydraulic fluid, is used as a pressure-maintaining ballast during the vehicle <NUM>'s return trip from the destination facility <NUM> to the source facility <NUM> (or another source facility <NUM>).

The nitrogen ballast is provided by a nitrogen source (e.g., an air separation unit combined with a compressor and cooling system to cool the compressed nitrogen to at or near the cold storage temperature). The nitrogen source delivers cold, compressed nitrogen to a nitrogen delivery connector that can be connected to the connector <NUM> of the vehicle <NUM> (or a separate nitrogen-dedicated connector that connects to the vessel <NUM> of the vehicle <NUM>).

In various nitrogen ballast embodiments, CNG is unloaded from the vehicle <NUM> to the destination facility <NUM> as described above, which results in the vessels <NUM> being filled with hydraulic fluid. At that point, the connector <NUM> can be disconnected from the connector <NUM> of the vehicle <NUM>, and the outlet connector of the nitrogen source is connected to the connector <NUM> of the vehicle <NUM>. Cold compressed nitrogen is them injected into the vessels <NUM> while hydraulic fluid is displaced out of the vessels <NUM> in the same or similar manner that CNG was transferred to the vessels <NUM> at the source facility <NUM>, all while maintaining the vessels <NUM> at or near their desired storage pressure and temperature so as to minimize stresses on the vessels <NUM>. Once the hydraulic fluid is evacuated from the vessels <NUM>, the vehicle <NUM>'s connectors <NUM>, <NUM> are separated from the destination facility connectors and the vehicle <NUM> can return to the source facility <NUM>.

At the source facility <NUM>, hydraulic fluid is injected into the vessels <NUM> (e.g., via the pump <NUM>) from the reservoir <NUM> to displace the nitrogen ballast, which can either be vented to the atmosphere or collected for another purpose. The vehicle <NUM> is then filled with CNG from the source facility <NUM> in the manner described above.

In the above-described embodiment, hydraulic fluid is filled into the vessels <NUM> between when the vessels <NUM> are emptied of one of CNG or nitrogen and filled with the other of CNG or nitrogen. The intermediate use of hydraulic fluid as a flushing medium discourages, reduces, and/or minimizes the cross-contamination of the CNG and nitrogen. According to various embodiments, some mixing of nitrogen into the CNG is acceptable, particularly because nitrogen is inert. However, according to various alternative embodiments, a piston or bladder may be included in the vessels <NUM> to maintain a physical barrier between the CNG side of the piston/bladder and the ballast side of the piston/bladder. In such an alternative embodiment, the intermediate hydraulic fluid flush can be omitted.

According to various embodiments, the use of such a nitrogen ballast system can avoid the need for the vehicle <NUM> to transport hydraulic fluid from the destination facility <NUM> back to the source facility <NUM>, while still maintaining the vessels <NUM> at the desired pressure.

The use of pressurized hydraulic fluid and/or other ballast fluid during the above-discussed CNG transfer process into and out of the vessels <NUM> enables the pressure within the vessels <NUM> of the units <NUM>, <NUM>, <NUM> to be consistently maintained at or around a desired pressure (e.g., within <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM> % of a psig set point (e.g., a certain pressure); within <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM> psi of a psig set point (e.g., a certain pressure)). According to various embodiments, the set point/certain pressure is (<NUM>) at least <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM> psig, (<NUM>) less than <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM>, (<NUM>) between any two such values (e.g., between <NUM> and <NUM> psig, between <NUM> and <NUM> psig, and/or (<NUM>) about <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM> psig. According to various non-limiting embodiments, the vessels <NUM> therefore remain generally isobaric during the operational lifetime. According to various non-limiting embodiments, maintaining the vessel <NUM> pressure at or around a desired pressure tends to reduce the cyclic stress fatigue that plagues pressure vessels that are repeatedly subjected to widely varying pressures as they are filled/loaded and emptied/unloaded.

According to various embodiments, various transfers of CNG into the vessel <NUM> results in hydraulic fluid occupying less than <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM>% of an internal volume of the vessel <NUM>. According to various embodiments, before such transfers, hydraulic fluid occupied at least <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM>% of a volume of the vessel. According to various embodiments, a volume of hydraulic fluid in the vessel <NUM> before the transfer exceeds a volume of hydraulic fluid in the vessel <NUM> after such transfer by least <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM>% of an internal volume of the vessel <NUM>.

According to various non-limiting embodiments, the reduced fatigue on the vessels <NUM> facilitates (<NUM>) a longer useful life for each vessel <NUM>, (<NUM>) vessels <NUM> that are built to withstand less fatigue (e.g., via weaker, lighter, cheaper, and/or thinner-walled materials), and/or (<NUM>) larger capacity vessels <NUM>. According various embodiments, and as shown in <FIG>, various of the vessels <NUM> are generally tubular/cylindrical with bulging (e.g., convex, hemispheric) ends. According to various non-limiting embodiments an outer diameter D of the vessel <NUM> is (<NUM>) at least <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and/or <NUM> feet, (<NUM>) less than <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM> feet, and/or (<NUM>) between any two such values (e.g., between <NUM> and <NUM> feet, between <NUM> and <NUM> feet, between <NUM> and <NUM> feet, about <NUM> feet). According to various non-limiting embodiments, a length L of the vessel <NUM> is (<NUM>) at least <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM> feet, (<NUM>) less than <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM> feet, and/or (<NUM>) between any two such values (e.g., between <NUM> and <NUM> feet, about <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM> feet). According to various embodiments, a ratio of L:D is (<NUM>) at least <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, and/or <NUM>:<NUM>, (<NUM>) less than <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, and/or <NUM>:<NUM>, and/or (<NUM>) between any two such upper and lower values (e.g., between <NUM>:<NUM> and <NUM>:<NUM>, between <NUM>:<NUM> and <NUM>:<NUM>). According to various embodiments, the diameters and lengths of the vessels <NUM> may be tailored to the particular use of the vessels <NUM>. For example, longer and/or larger diameter vessels <NUM> may be appropriate for the storage unit <NUM> of a large vehicle <NUM> such as a large ocean-going ship in which a substantial portion of the ship's cargo area is devoted to the storage unit <NUM>.

According to various embodiments, each vessel <NUM> may be a low-cycle intensity pressure vessel (e.g., used in applications in which the number of load/unload cycles per year is less than <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM>).

According to various embodiments, an interior volume of an individual vessel <NUM> is (<NUM>) at least <NUM>,<NUM>, <NUM>,<NUM>, <NUM>,<NUM>, <NUM>,<NUM>, <NUM>,<NUM>, <NUM>,<NUM>, <NUM>,<NUM>, <NUM>,<NUM>, <NUM>,<NUM>, <NUM>,<NUM>, <NUM>,<NUM>, <NUM>,<NUM>, <NUM>,<NUM>, and/or <NUM>,<NUM> liters, (<NUM>) less than <NUM>,<NUM>, <NUM>,<NUM>, <NUM>,<NUM>, <NUM>,<NUM>, and/or <NUM>,<NUM> liters, and/or (<NUM>) between any two such upper and lower volumes (e.g., between <NUM>,<NUM> and <NUM>,<NUM> liters, between <NUM>,<NUM> and <NUM>,<NUM> liters).

As shown in <FIG>, if the vessels <NUM> are to be disposed horizontally in their unit <NUM>, <NUM>, <NUM> (i.e., such that an axis of their tubular shape is generally horizontally disposed), hydraulic fluid and CNG dip tubes <NUM>, <NUM> may be used to generally ensure that heavier hydraulic fluid <NUM> flows only out of the dip tube <NUM> and connected hydraulic port 120b, 320b, 520b and that lighter CNG <NUM> flows only out of the dip tube <NUM> to the port 120a, 320a, 520a. As shown in <FIG>, the hydraulic fluid dip tube <NUM> bends downwardly within the volume 400a of the vessel <NUM> such that its end opening 800a is disposed at or near a gravitational bottom of the volume 400a. Conversely, the CNG dip tube <NUM> bends upwardly within the volume 400a of the vessel such that its end opening 810a is disposed at or near a gravitational top of the volume 400a. According to various embodiments, the vessel <NUM> may be slightly tilted relative to horizontal (counterclockwise as shown in <FIG>) so as to place the end opening 800a closer to the gravitational bottom of the volume 400a and to place the end opening 810a closer to the gravitational top of the volume 400a.

As shown in <FIG>, protective impingement deflectors <NUM> (e.g., plates) are disposed just past the end openings 800a, 810a of the dip tubes <NUM>, <NUM>. The deflectors <NUM> may be mounted to the dip tubes <NUM>, <NUM> or to the adjacent portions of the vessels <NUM> (e.g., the interior surface of the vessel <NUM> adjacent to the opening of the dip tube <NUM>, <NUM>. Flow of fluid (e.g., CNG <NUM>, hydraulic fluid <NUM>) into the vessel volume 400a via the dip tubes <NUM>, <NUM> and openings therein tends to cause the fluid to impinge upon the internal walls/surfaces of the vessel <NUM> that define the volume 400a, which can erode and damage the vessel <NUM> walls. The impingement deflectors <NUM> are disposed between the openings 800a, 810a and the adjacent vessel <NUM> walls so that inflowing fluid <NUM>, <NUM> impinges upon the deflectors <NUM>, instead of the vessel <NUM> walls. The deflectors <NUM> therefore extend the useful life of the vessels <NUM>.

While the above-discussed embodiments maintain the vessels <NUM> at a relatively consistent pressure, such pressure maintenance may be omitted according to various alternative embodiments. According to various alternative embodiments, the hydraulic fluid reservoirs, pumps, nitrogen equipment, and/or associated structures are eliminated. As a result, the pressures in the vessels <NUM> drop significantly when the vessels <NUM> are emptied of CNG, and rise significantly when the vessels <NUM> are filled with CNG. According to various embodiments, these pressure fluctuations result in greater fatigue, which may result in (<NUM>) a shorter useful life for each vessel <NUM>, (<NUM>) the use of vessels <NUM> that are stronger and more expensive, and/or (<NUM>) the use of smaller capacity vessels <NUM>.

When the vessels <NUM> are disposed horizontally, their middle portions tend to sag downwardly under the force of gravity. Accordingly, longitudinally-spaced annular hoops/rings <NUM> may be added to the cylindrical portion of the vessels <NUM> to provide support. According to various embodiments, the rings <NUM> comprise <NUM>% nickel steel (e.g., when the cold storage temperate is around -<NUM>). According to various non-limiting embodiments, for vessels designed for warmer temperatures (e.g., -<NUM>), less expensive steels (e.g., A333 or impact tested steel) may be used. A plurality of circumferentially-spaced tension bars <NUM> extend between the hoops <NUM> to pull the hoops <NUM> toward each other. The bars <NUM> may be tensioned via any suitable tensioning mechanism (e.g., threaded fasteners at the ends of the bars <NUM>; turn-buckles disposed along the tensile length of the bars <NUM>; etc.). In the illustrated embodiment, two hoops <NUM> are used for each vessel <NUM>. However, additional hoops <NUM> may be added for longer vessels <NUM>. The hoops <NUM> and tension bars <NUM> tend to discourage the vessel <NUM> from sagging, and tend to ensure that the ends of the vessel <NUM> to not bend, which might adversely affect rigid fluid passageways connected to the ends of the vessel <NUM>.

According to various embodiments, a membrane/liner of the vessel <NUM> may be supported by balsa wood or some other structural support that is not impermeable but can provide a mechanical support upon which the membrane conforms to.

As shown in <FIG>, the vessels <NUM> may incorporate a burst-avoidance system <NUM> disposed between the dip tube <NUM> and port 120a, 320a, 520a. The system <NUM> includes a normally-open valve <NUM> disposed in the passageway connecting the dip tube <NUM> to the.

port120a, 320a, 520a (or anywhere else along the CNG passageway connected to the volume 400a of the vessel). The system <NUM> also includes a passageway <NUM> that fluidly connects the volume 400a (e.g., via the dip tube <NUM>) to a vent <NUM> (e.g., to a safe atmosphere, etc.). A burst object <NUM> (e.g., a disc of material) is disposed in the passageway <NUM>. The burst object blocks the passageway <NUM> and prevents fluid flow from the vessel volume 400a to the vent <NUM>. The burst object 920is made of a material with a lower and/or more predictable failure point than the material of the vessel <NUM> walls. For example, the burst object <NUM> may be made of a material that is identical to, but slightly thinner than, the walls of the vessel <NUM>. The burst object <NUM> and vessel <NUM> walls are subjected to the same pressures and fatigues as the vessel <NUM> is used. As both the vessel <NUM> walls and burst object <NUM> weaken with use, the burst object <NUM> will fail before the vessel <NUM> walls. When the burst object <NUM> fails, fluid from the vessel <NUM> passes by the failed burst object within the passageway <NUM> and is safely vented out of the vent <NUM>. A pressure or flow sensor <NUM> is operatively connected to the valve <NUM> and is disposed in the passageway <NUM> between the burst object <NUM> and vent <NUM> detects the flow of fluid therethrough as a result of the burst object <NUM> failure. The detection of such flow by the sensor <NUM> triggers the valve <NUM> to close. Alarms may also be triggered. The vessel <NUM> can then be safely replaced.

According to various embodiments, and as shown in <FIG>, the vessels <NUM> may be manufactured by first inflating a bladder <NUM> that has the intended shape of the volume 400a. A liner <NUM> is then formed on the inflated bladder. For vessels <NUM> intended to be used at ambient temperatures (e.g., well warmer -<NUM>), the liner <NUM> may be formed from a material such as HDPE. According to various embodiments in which the working temperature of the vessel <NUM> and its contents is colder (e.g., -<NUM>), ultra-high molecular weight polyethylene (UHMWPE) may be used, since such material has good strength properties at such low temperatures. According to various non-limiting embodiments, the liner <NUM> is (a) less than <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM> thick, (b) at least <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM> thick, and/or (c) between any two such values (e.g., between <NUM> and <NUM> thick). According to various non-limiting embodiments, thinner liners <NUM> are used for vessels <NUM> that are not subjected to severe pressure fatigue (e.g., embodiments in which hydraulic fluid or nitrogen is used to maintain a consistent pressure in the vessel <NUM>). According to various non-limiting embodiments, for very large diameter and/or thick walled vessels <NUM>, the anti-permeation properties of the composite resin used with the fiberglass and/or carbon fiber layers may be enough to pass permeation test requirements even in the absence of a liner, in which case the liner may be omitted. According to various non-limiting embodiments, when the vessels <NUM> are Type <NUM> vessels <NUM>, the liner may be omitted.

A full fiberglass layer <NUM> is then built up around the liner <NUM> while the inflated bladder <NUM> supports the liner <NUM>.

As shown in <FIG>, a carbon fiber layer <NUM> is added to strengthen critical portions of the vessel <NUM>. For example, carbon fiber <NUM> is wrapped diagonally from an edge of the hemispheric shape on one side of the liner <NUM> to a diagonal edge of the hemispheric shape on the other side of the liner <NUM>. According to various embodiments, the carbon fiber layer <NUM> may be wrapped before, during, or after the fiberglass layer <NUM> is formed.

After wrapping, the bladder <NUM> can then be deflated and removed. The dip tubes <NUM>, <NUM> can then be sealingly added to form the vessels <NUM>.

According to various embodiments, the fiberglass layer <NUM> is homogeneous with fiberglass extending in all directions. Conversely, the carbon fiber layer <NUM> is nonhomogeneous, as the carbon fiber <NUM> extends predominantly only in the diagonal or parallel direction illustrated in <FIG>. According to various embodiments, in smaller diameter pressure vessels <NUM>, the carbon fiber may be wrapped only along the diagonals, but in larger diameter pressure vessels <NUM>, the carbon fiber may form complete, homogeneous layer. According to various embodiments, a smaller diameter vessel <NUM> may having <NUM>-<NUM> layers of carbon fiber, while a larger diameter vessel <NUM> may utilize <NUM> or more layers of carbon fiber.

According to various embodiments, a mass-based ratio of fiberglass: carbon-fiber in the vessel <NUM> is at least <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, <NUM>:<NUM>, <NUM>: <NUM>, and/or <NUM>: <NUM>.

After wrapping of the layers <NUM> and/or <NUM>, the vacuum may be pulled on the wrapped layers <NUM> and/or <NUM> to press the layers <NUM> and/or <NUM> against the liner <NUM> and prevent void spaces between the liner <NUM> and layers <NUM> and/or <NUM>.

A resin may then be applied to the layers <NUM>, <NUM> to set the layers <NUM>, <NUM> in place and strengthen them. According to various embodiments, the resin is an ambient temperature cure resin that is nonetheless designed to operate at the designed operating temperatures of the vessels <NUM> (e.g., -<NUM> for embodiments utilizing cold storage units <NUM>, <NUM>, <NUM>; ambient temperatures for embodiments not relying on cold storage).

According to various non-limiting alternative embodiments, the fiberglass and/or carbon fiber may be impregnated with resin before application to the vessel <NUM> being created (e.g., during manufacturing of the fibers) in a process known as wet winding.

According to various embodiments, the hybrid use of fiberglass and carbon fiber to construct the vessel <NUM> balances the cost advantages of inexpensive fiberglass <NUM> (relative to the cost of carbon fiber <NUM>) with the weight, strength, and/or fatigue-resistance advantages of carbon fiber <NUM> (relative to lower strength, heavier, and less fatigue resistant fiberglass <NUM>).

According to various non-limiting embodiments, the use of carbon fiber improves the fire safety of the vessel <NUM> due to improved heat conduction/dissipation inherent to carbon fibers in comparison to less conductive materials such as glass fiber. The heat conductivity of the carbon fiber may trigger an exhaust safety valve (thermally actuated) faster than less conductive materials.

According to various regulations (e.g., EN-<NUM>), a pressure vessel's maximum working pressure depends on the vessel material. For example, the failure strength of a steel pressure vessel may be required to be <NUM> times its maximum working pressure (i.e., a <NUM> factor of safety). Carbon fiber pressure vessels may require a <NUM> to <NUM> factor of safety for operating pressures. Fiberglass pressure vessels may require a <NUM> to <NUM> factor of safety, which may force manufacturers to add extra, thick, heavy layers of fiberglass to fiberglass-based pressure vessels. According to various embodiments, the hybrid fiberglass/carbon-fiber vessel <NUM> can take advantage of the lower carbon fiber factor of safety because the most fatigue-vulnerable portion of the vessel <NUM> is typically the corner-to-corner strength (but may be additionally and/or alternatively in other directions), and that portion of the vessel <NUM> is strengthened with carbon fiber <NUM>.

According to various embodiments, reinforcing annular rings such as the rings <NUM> shown in <FIG> may be added to the vessels <NUM> before, during, or after the fiberglass and/or carbon fiber layers <NUM>, <NUM> are added. Accordingly, the reinforcing rings <NUM> may be integrated into the reinforcing fiber structure <NUM>, <NUM> of the vessel <NUM>. According to various embodiments, the rings <NUM> may tend to prevent catastrophic bursts of the vessels <NUM> by stopping the progression of a rip in the liner <NUM>. In particular, rips in cylinder-shaped vessels such as the vessel <NUM> tend to propagate along the longitudinal direction (i.e., parallel to an axis of the cylindrical portion of the vessel <NUM>). As shown in <FIG>, the reinforcing rings <NUM> extend in a direction perpendicular to the typical rip propagation direction. As a result, the rings <NUM> tends to prevent small longitudinal rips in the liner <NUM> from propagating into large and/or catastrophic ruptures.

According to various embodiments, reinforcing rings <NUM> may be added before the fiberglass and/or carbon fiber layers <NUM>, <NUM> so as to help support the hemispherical ends/heads during wrapping of the fiberglass and/or carbon fiber layers <NUM>, <NUM>. The reinforcing rings <NUM> may also make circular wrapping of the cylindrical body easier by providing support points.

According to various embodiments, a metal boss may be used to join the CNG dip tubes <NUM>, <NUM> (or other connectors) to a remainder of the vessels <NUM>.

<FIG> illustrates an embodiment in which the insulated space <NUM> illustrated in <FIG> is incorporated into a jacket of the vessel <NUM>. In <FIG>, the insulated space <NUM> is illustrated as a rectangular, box-like shape. However, as shown in <FIG>, an alternative insulated space <NUM> may follow the contours of the vessel <NUM>. The insulated space <NUM> is defined between the vessel <NUM> and a surrounding layer of insulation <NUM> that is encased within a jacket <NUM>. According to various embodiments, the jacket <NUM> comprises a polymer or metal (e.g., <NUM>% nickel steel). The jacket <NUM> may provide impact protection to the vessel <NUM> and/or partial containment in case of a leak/rupture of the vessel <NUM>. As shown in <FIG>, the cooling system <NUM> forms solid CO<NUM> <NUM> in the space <NUM>. Alternatively, a similar cooling system may deliver liquid CO<NUM> to the space <NUM>.

According to various embodiments, the rings <NUM> may structurally interconnect the vessel <NUM> and the insulation <NUM> and jacket <NUM>. Holes may be formed in the rings <NUM> to permit coolant flow past the rings <NUM> within the space <NUM>. Alternatively, sets of parallel coolant ports 440b, 440a may be disposed in different sections of the space <NUM>.

<FIG> illustrates the vessel <NUM> in a horizontal position. However, the vessel <NUM> and associated space <NUM>, insulation <NUM>, and jacket <NUM> may alternatively be vertically oriented so as to have the general orientation of the vessel <NUM> shown in <FIG>.

While the above-discussed embodiments are described with respect to the storage and transportation of CNG, any of the above-discussed embodiments can alternatively be used to store and/or transport any other suitable fluid (e.g., other compressed gases, other fuel gases, etc.) without deviating from the scope of the present invention.

Unless otherwise stated, a temperature in a particular space (e.g., the interior of the vessel <NUM>) means the volume-weighted average temperature within the space (without consideration of the varying densities/masses of fluids in different parts of the space).

Claim 1:
A cold compressed gas storage and transportation vehicle (<NUM>) comprising:
a vehicle (<NUM>);
a compressed gas storage vessel (<NUM>) supported by the vehicle (<NUM>);
a hydraulic fluid reservoir (<NUM>) supported by the vehicle (<NUM>);
a passageway (<NUM>) connecting the hydraulic fluid reservoir (<NUM>) to the compressed gas storage vessel (<NUM>);
a pump (<NUM>, <NUM>) disposed in the passageway (<NUM>) and configured to selectively pump hydraulic fluid through the passageway (<NUM>) from the reservoir (<NUM>) into the compressed gas storage vessel (<NUM>); and
an insulated space (<NUM>) supported by the vehicle (<NUM>), wherein the vessel (<NUM>) is disposed in the insulated space (<NUM>)
characterized by
a carbon-dioxide-refrigerant-based refrigeration unit (<NUM>) supported by the vehicle (<NUM>) and configured to cool the insulated space (<NUM>);
wherein the refrigeration unit (<NUM>) is configured to deposit solid carbon dioxide into the insulated space (<NUM>);
wherein the refrigeration unit (<NUM>) is configured to provide passive, sublimation-based cooling to the insulated space (<NUM>) when solid carbon dioxide is in the insulated space (<NUM>), even when the refrigeration unit (<NUM>) is off; and
wherein the refrigeration unit (<NUM>) is configured to maintain a temperature within the insulated space (<NUM>) between -<NUM> and -<NUM> degrees C.