Process for blending two or more liquefied hydrocarbon streams

Abstract

A process for blending two liquefied hydrocarbon streams, in particular from two vessels. The method includes pumping a first liquefied hydrocarbon stream to a first blending point; pumping the second liquefied hydrocarbon stream to a first blending point; the first liquefied hydrocarbon stream and the second liquefied hydrocarbon stream are combined at the blending point in a volume ratio of the first liquefied hydrocarbon stream to the second liquefied hydrocarbon stream of 1: 500, preferably 1: 100 and up to 500: 1 to provide a combined stream. The combined stream is provided from the first blending point back to the inlet of the source of the first liquefied hydrocarbon via the combination conduit at an operating pressure above the saturation pressure of the combined stream at least as the combined stream travels from the first blending point to a final valve immediately upstream of the inlet of the source of the first liquefied hydrocarbon.

Description

Technical Field

[0001] This specification relates in general to the field of hydrocarbon blending, and more specifically to methods for blending two or more liquefied hydrocarbon streams. Background Technology

[0002] This section aims to introduce various aspects of the art that may be associated with exemplary embodiments of the present invention. It is believed that this discussion will help provide a framework for a better understanding of specific aspects of the invention. Therefore, it should be understood that this section should be read in this light and not necessarily as an admission of any prior art.

[0003] Commercially, it is generally important to cryogenically liquefy natural gas to produce LNG, which facilitates its storage and transportation. The fundamental reason for natural gas liquefaction is that liquefaction reduces volume, making it possible to store and transport large quantities of liquefied gas in containers at low or even atmospheric pressure in an economical manner, thus providing a technically reliable and safe solution when pipeline transportation is impractical or economically infeasible.

[0004] It is known that LNG products, which are primarily composed of methane, are blended with another component, such as light hydrocarbons (e.g., ethane, propane, or butane), to increase the calorific value of LNG to meet market demands. For example, US20140338393 discloses a method for producing blends of LNG by blending lean and rich LNG together to meet specific requirements of operators at production facilities, application sites, or refueling stations. As another example, WO2005093017 discloses compositions suitable for use as fuel compositions comprising natural gas and a mixture of synthetic light hydrocarbons (such as C2 to C5 alkanes, alkenes, and mixtures thereof) obtained through hydrocarbon synthesis reactions, particularly blends of such synthetic light hydrocarbons with natural gas derived from LNG produced in LNG processes. As yet another example, US8381544 discloses a method for altering the calorific value of LNG by adding a higher calorific value component, wherein the higher calorific value component stream is first cooled with LNG before being combined with the LNG.

[0005] Furthermore, US 11416012 discloses the online mixing of hydrocarbon liquids from multiple tanks into a single pipeline, wherein the hydrocarbon liquids are typically those that exist in a liquid state under atmospheric conditions, such as hydrocarbons, gasoline, crude oil, pyrolysis oil, etc., which exist as viscous liquids in underground geological structures and on the surface. Therefore, this patent reference does not address the challenges of blending liquefied hydrocarbons.

[0006] However, these disclosures do not address the potential challenges associated with blending two liquefied hydrocarbon streams with different properties, such as density. Therefore, an improved method for blending two or more liquefied hydrocarbon streams is desired. These and other objectives will become apparent from the disclosures provided herein. Summary of the Invention

[0007] A method is provided for blending two or more liquefied hydrocarbon streams between at least two vessels, wherein a first vessel includes a first storage container for storing a first liquefied hydrocarbon, optionally liquefied natural gas, and wherein a second vessel includes a second storage container for storing a second liquefied hydrocarbon, optionally selected from the group consisting of liquefied ethane, liquefied butane, liquefied propane, and any combination thereof. The method includes: (a) providing a conduit network between the at least two vessels, the conduit network including: (i) a first blending point, optionally part of a liquidation manifold of the second vessel; (ii) a first conduit section, optionally part of a liquidation manifold of the first vessel, to provide fluid communication between the first storage container and the first blending point; (iii) a second conduit section, optionally part of a liquidation manifold of the second vessel, to provide fluid communication between the second storage container and the first blending point; and (iv) a combined conduit providing fluid communication downstream of the first blending point and returning to the inlet of the first storage container. The combined conduit includes a final valve immediately upstream of the inlet of the first storage container. The method further includes (b) pumping a first liquefied hydrocarbon stream from the first storage container via a first conduit section to a first blending point; (c) pumping a second liquefied hydrocarbon stream from a second storage container via a second conduit section to the first blending point; (d) merging the first and second liquefied hydrocarbon streams at the first blending point at a volume ratio in the range of 1:500, preferably 1:100, and up to 500:1 to provide a combined stream; (e) providing at least a portion (including all) of the combined stream from the first blending point back to the first storage container via the combined conduit, thereby providing a combined product to the first storage container; and (f) when the combined stream is located between the combined conduit section between the first blending point and the final valve, providing the combined stream with an operating pressure higher than the saturation pressure of the combined stream (preferably at least 0.1 bar higher, more preferably at least 0.5 bar higher, and most preferably at least 1.2 bar higher).

[0008] Optionally, in some embodiments, the combined conduit further includes a first subsequent blending point downstream of the first blending point and optionally upstream of the final valve 126. In such embodiments, the method may further include: (g) providing a second stream of the first liquefied hydrocarbon from a source of the first liquefied hydrocarbon (optionally a first storage container) to the first subsequent blending point; and (h) merging the combined stream and the second stream of the first liquefied hydrocarbon at the first subsequent blending point at a volume ratio in the range of 25:1, preferably 50:1, and up to 500:1, wherein the first stream of the first liquefied hydrocarbon and the second liquefied hydrocarbon ethane stream are merged at the first blending point at a volume ratio in the range of 1:500, preferably 1:100, and up to 50:1. Optionally, the combined conduit may further include a second subsequent blending point located downstream of the first subsequent blending point, upstream or downstream of the final valve, and upstream of the inlet of the first storage container. In such embodiments, the method may further include: (i) providing a third stream of the first liquefied hydrocarbon from a source of the first liquefied hydrocarbon (optionally a first storage container) to a second subsequent blending point; and (j) merging the combined stream and the third stream of the first liquefied hydrocarbon at the second subsequent blending point at a volume ratio in the range of 25:1, preferably 50:1, and up to 150:1, wherein the first liquefied hydrocarbon stream and the second liquefied hydrocarbon stream are merged at the first blending point at a volume ratio in the range of 1:500, preferably 1:100, and up to 50:1, and wherein the combined stream and the second stream of the first liquefied hydrocarbon are merged at the first subsequent blending point at a volume ratio in the range of 100:1, preferably 150:1, and up to 500:1.

[0009] Optionally, in some embodiments, the combined conduit further includes a subsequent blending point located downstream of the final valve and upstream of the inlet of the first storage container. In such embodiments, the method may further include: (g) providing another stream of the first liquefied hydrocarbon from a source of the first liquefied hydrocarbon to the subsequent blending point, optionally wherein the source is the first storage container; and (h) merging the combined stream and the other stream of the first liquefied hydrocarbon at the subsequent blending point at a volume ratio in the range of 25:1, preferably 50:1, and up to 500:1, and wherein the first stream of the first liquefied hydrocarbon and the second stream of the first liquefied hydrocarbon are merged at the first blending point at a volume ratio in the range of 1:500, preferably 1:100, and up to 50:1.

[0010] Optionally, in some embodiments, the combined stream downstream of the first final valve and downstream of any subsequent blending point has a volume ratio of at least 2:1, preferably at least 3:1 and more preferably 4:1 of the first liquefied hydrocarbon, preferably LNG, to the second liquefied hydrocarbon, preferably liquefied ethane.

[0011] Optionally, in some embodiments, the conduit network may further include at least one of a pull-down line and an in-tank spray manifold to introduce the combined flow from the combined conduit 116 into the first storage tank. Optionally, the pull-down line and / or the in-tank spray manifold also include their respective final valves immediately upstream of their outlets. In such embodiments, the method may further include providing an operating pressure to the conduit section between the combined conduit and the respective final valves of the pull-down line and / or the in-tank spray manifold that is higher than the saturation pressure of the combined flow (preferably at least 0.1 bar higher, more preferably at least 0.5 bar higher, and most preferably at least 1.2 bar higher).

[0012] Optionally, in some embodiments, the method may also include providing a total operating pressure of at least 2 bar to the catheter network.

[0013] Optionally, in some embodiments, the method may further include: providing the first storage container with an operating pressure that is higher than the saturation pressure of the merged stream (preferably at least 5% higher, more preferably at least 50% higher, and most preferably at least 100% higher).

[0014] Optionally, in some embodiments, the method may further include: performing steps (a)-(e) sequentially, and, where applicable, performing steps (f)-(j) sequentially, until the desired amounts of the first liquefied hydrocarbon and / or the second liquefied hydrocarbon have been combined. Optionally, the method may further include returning the operating pressure of the conduit network to the standard operating pressure, and returning the operating pressure of the first storage container to the standard operating pressure.

[0015] Optionally, in some embodiments, the method may further include: providing the combined product from the first storage container to another storage container on the first vessel.

[0016] Optionally, in some embodiments, the method may also include storing the combined products as inventory in a first storage container. Attached Figure Description

[0017] Figure 1 A diagram depicts an exemplary embodiment of a system for blending two or more liquefied hydrocarbon streams according to aspects disclosed in this disclosure.

[0018] Figure 2 A diagram depicts an exemplary embodiment of another system for blending two or more liquefied hydrocarbon streams according to aspects disclosed in this disclosure.

[0019] Figure 3 A diagram depicts an exemplary embodiment of yet another system for blending two or more liquefied hydrocarbon streams according to aspects disclosed in this disclosure.

[0020] Figure 4A diagram depicts an exemplary embodiment of yet another system for blending two or more liquefied hydrocarbon streams according to aspects disclosed in this disclosure. Detailed Implementation

[0021] The invention will now be described in detail with reference to embodiments thereof as illustrated in the accompanying drawings. References to “an embodiment,” “an embodiment,” “exemplary embodiment,” etc., indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment need to include that particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is believed that, to the knowledge of those skilled in the art, combining it with other embodiments will affect that feature, structure, or characteristic, whether explicitly described or not. Other suitable modifications and adjustments to various conditions and parameters commonly encountered in the art, and which will be apparent to those skilled in the art, are within the spirit and scope of the invention.

[0022] While the description herein provides many specific details set forth for a thorough understanding of the illustrative embodiments, it will be apparent to those skilled in the art that the embodiments may be practiced without some or all of these specific details. In other instances, well-known process steps and / or structures have not been described in detail so as not to unnecessarily obscure the invention. The features and advantages of the embodiments will be better understood with reference to the accompanying drawings and the following discussion.

[0023] Furthermore, when similar elements are used in one or more figures, the same reference numerals will be used in each figure, and a detailed description of the element will be provided only when it first appears. For clarity, some features or components of the system or method described herein may be omitted in some depicted constructions.

[0024] When blending LNG products with lighter hydrocarbons, a common concern is the formation of stratified liquid layers (or stratification) of different densities within the storage tank. Typically, heat leaking through the tank walls into the blended LNG product slowly heats the blended LNG in contact with the tank walls and bottom. This warmer blended LNG has a lower density, which increases its buoyancy, slowly causing it to rise in the main LNG column. At the top of the liquid column (liquid-vapor interface), the warmer LNG releases the accumulated excess heat through evaporation, becoming cooler and denser, which in turn reduces its buoyancy, slowly causing the cooler blended LNG to fall in the main LNG column. This natural convection occurs continuously as long as the density difference within the main blended LNG column is less than 1%. When the density difference in the main column is greater than 1%, distinct LNG layers will form, disrupting the natural convection of the main LNG. When there is a possibility of introducing LNG blends with different densities into the same tank, particularly when the density difference between lean LNG (methane) and liquefied ethane is at least 10%, maintaining homogeneity and mitigating stratification are essential. Once stratified liquid layers form, overturning can occur when the density difference between the two layers becomes small enough that natural convection from the bottom layer reaches the free surface. The subsequent mixing of these layers is accompanied by a significant increase in the normal vaporization rate, which will be proportional to the superheat that accumulates in the bottom layer. This physical phenomenon associated with the mixing of stratified LNG layers is commonly and descriptively referred to as "overturning." However, high-intensity overturning can lead to the release of vapors exceeding the tank's design vapor handling capacity, and thus can cause overpressure and potentially tank rupture.

[0025] Although this disclosure generally refers to LNG and ethane as two liquefied hydrocarbon streams that benefit from the blending methods described herein, it should be understood that the principles provided in this disclosure can be applied to blending other liquefied hydrocarbon streams, such as (i) LNG with liquefied propane, or (ii) LNG with liquefied ethane, liquefied propane, liquefied butane, and any combination thereof.

[0026] As used herein, the term "hydrocarbon" has its general meaning, encompassing molecules composed of carbon and hydrogen in various combinations, and can be fossil (e.g., natural gas) or of biological origin (e.g., biogenic methane). The term "liquefied hydrocarbon" refers to a hydrocarbon that exists as a gas at atmospheric pressure and temperature, and will change state and become liquid under new pressure and temperature conditions due to a decrease in temperature and / or an increase in pressure, or a combination of both. In some cases (such as in natural gas liquefaction), this phase change can also be combined with a subsequent reduction in operating pressure to meet downstream processes (e.g., atmospheric storage of LNG), further lowering the temperature of the liquefied hydrocarbon stream. The specific combination of pressure and temperature during gas liquefaction varies depending on the type of hydrocarbon. Furthermore, hydrocarbons can be described as light or heavy depending on the number of carbon and hydrogen atoms in the molecule. Examples of liquefied hydrocarbons include alkanes (or chain alkanes) such as methane -CH4; ethane -C2H6; propane C3H8; butane: n-butane and isobutane -C4H6. 10 Natural gasoline or pentane plus-C5H 12 ; and heavier substances); and olefins (or chain olefins) (such as ethylene-C2H 44 propylene-C3H6, n-butene and isobutene-C4H8).

[0027] This disclosure provides a method for blending two liquefied hydrocarbon streams at a floating facility to produce liquefied natural gas with a desired composition, namely by using a combination of floating assets for at least the storage and transport of liquefied hydrocarbons, such as LNG carriers operating in combination with vessels carrying another type of liquefied hydrocarbon (e.g., ethane-compatible multi-gas carriers), or LNG FSRUs operating in combination with vessels carrying another type of liquefied hydrocarbon, and any floating facility capable of processing liquefied hydrocarbons and any floating facility capable of processing LNG. Additionally, certain embodiments of the method described herein can be suitably adapted for blending lean LNG with liquefied ethane to utilize the existing infrastructure of the respective LNG facility or site to meet desired LNG and / or natural gas specifications (such as Wobbe Index (WI), Low Heating Value (LHV), Methane Number (MN), or Incomplete Combustion Factor (ICF)).

[0028] Figures 1 to 4 Various arrangements of two vessels are depicted, each carrying a corresponding liquefied hydrocarbon component for blending. For example, vessel 100 includes a storage container 102 for storing a first liquefied hydrocarbon (preferably LNG), a second vessel 104 for storing a second liquefied hydrocarbon (preferably ethane), and a network of conduits in fluid communication with both the storage container 104 and the second vessel 104.

[0029] Liquefied natural gas (LNG) is cooled and liquefied natural gas (primarily methane). Depending on the application, LNG can be stored in container 102 at temperatures below -110°C, and more typically below -145°C, such as between -159°C and -162°C. Generally, "lean" LNG has a relatively low calorific value, while "rich" LNG contains a larger proportion of heavier hydrocarbons, which gives it a higher calorific value. Lean LNG can be further enriched, such as through the methods described herein, to meet various market quality specifications, such as Wobbe Index (WI), Low Heating Value (LHV), Methane Number (MN), or Incomplete Combustion Factor (ICF).

[0030] The conduit network includes a first blending point (which, for reference to a preferred embodiment, may be referred to as LNG-ethane blending point 108), a first conduit section 110 (which may be referred to as LNG conduit 110 for a preferred embodiment where the first liquefied hydrocarbon is LNG), and a second conduit section 112 (which may be referred to as ethane conduit 112 for a preferred embodiment where the second liquefied hydrocarbon is ethane). The first conduit section 110 provides fluid communication between a first storage container 102 and the first blending point 108. The second conduit section 112 provides fluid communication between a second storage container 114 and the first blending point 108. The first blending point 108 is a fluid conduit joint between the first conduit section 110 and the second conduit section 112. Preferably, the first blending point 108 is a joint at the intersection between the liquid manifold of the first vessel 100 and the liquid manifold of the second vessel 104. Various conduits may be isolated to guide various liquids, as described herein. Suitable examples of blending point 108 include tees, Y-joints, mixing tees, Y-fittings, and any combination thereof. Examples of suitable first conduit segment 110 and second conduit segment 112 may be applicable segments of the fluid manifolds from the first vessel 100 and the second vessel 104, respectively. For example, optionally, the first mixing point 108 may be part of the fluid manifold of the second vessel 104; the first conduit segment 110 may optionally be part of the fluid manifold of the first vessel 100 and the transfer system (not shown) between the first and second vessels; and the second conduit segment 112 may optionally be part of the fluid manifold of the second vessel 104.

[0031] Depending on the application, liquefied ethane can be stored at temperatures below -30°C, and more typically below -75°C, such as between -80°C and -89°C. Although Figure 1Ethane source 114 is depicted as being on a land-based storage container, but it should be understood that, as those skilled in the art will know, ethane source 114 may suitably be additionally or alternatively stored on a vessel (liquefied ethane carrier). The conduit network also includes a combination conduit 116 to provide fluid communication downstream of the first blending point 108 and back to storage container 102. The combined flow may enter container 102 from combination conduit 116 via pull-down line 105 or in-tank spray manifold 107 or a combination of both. As those skilled in the art will know, the combined flow may be directed to container 102 for distribution to other suitable storage containers (not shown) on the first vessel 100.

[0032] Suitable storage for liquefied hydrocarbons such as LNG, liquefied ethane, and other substances mentioned herein is known to those skilled in the art. Suitable examples, for instance, may include a single-containment system, which typically has an inner wall or main container for containing refrigerated liquids and may be self-supporting. The inner container may be surrounded by an outer wall, thus forming an annular space that can remain insulated. The single-containment system may be further insulated, such as at the base and top, as well as externally. Another suitable example includes a double-containment system, which typically consists of a single-containment system with the addition of a secondary wall capable of containing both liquids and vapors.

[0033] A first stream of first liquefied hydrocarbons (preferably liquefied natural gas (LNG)) is pumped from storage container 102 through a first section 110 of a conduit (preferably LNG conduit 110) to a first blending point 108. See also Figure 1 The pumping of the LNG stream can be accomplished at least by pumping equipment 120. A liquefied ethane stream is pumped from ethane source 114 through ethane conduit 112 to LNG-ethane blending point 108. As used herein, the terms "liquefied ethane," "liquid ethane," or "ethane" refer to a liquefied hydrocarbon stream containing at least 50 mol%, preferably at least 95 mol%, of ethane. As mentioned elsewhere in this disclosure, liquefied hydrocarbons other than LNG and liquefied ethane can be blended using the methods described herein. For example, if LNG is blended with liquefied propane, the liquefied hydrocarbon stream for propane contains at least 50 mol%, preferably at least 95 mol%, of propane; and if it is liquefied butane, the stream contains at least 50 mol%, preferably at least 95 mol%, of butane. Optionally, if the liquefied hydrocarbon stream is not substantially composed of its syndiotactic components (e.g., a liquefied ethane stream is not substantially entirely ethane), the remainder of the stream is selected from the group consisting of ethane, methane, propane, butane, and any combination thereof, if applicable. For example, an example of a mixture of liquefied hydrocarbons as defined herein could be LPG, which represents liquefied petroleum gas, comprising mixtures primarily composed of propane, butane, or a mixture of both propane and butane.

[0034] See Figure 1The pumping of the liquefied ethane stream can be accomplished at least by pump equipment 118. The first LNG stream and the ethane stream are combined at the LNG-ethane blending point 108 at a volumetric blending ratio of 1:500 and up to 500:1, preferably 1:100 and up to 500:1, and more preferably 1:10 and up to 500:1, to provide a combined stream. It should be understood that those skilled in the art can take into account various factors, such as the specifications and safe operating range (SOE) of the equipment and infrastructure involved in the blending operation (e.g., conduit networks, pumps, storage containers, valves, etc.), to select appropriate flow rates for the first LNG stream and the liquefied ethane stream to achieve the desired blending ratio within the range described herein. The appropriate number and type of pumps used to implement the methods described herein are known to those skilled in the art. Additionally or alternatively, the pump equipment may be part of the existing infrastructure and equipment of the vessel (such as an LNG storage vessel and an ethane multipurpose carrier).

[0035] The merged stream is provided from the first blending point 108 back to the storage container 102 via at least a combined conduit 116. The storage tank 102 in container 100 may include multiple storage tanks (not shown), to which the merged stream may be provided individually and / or from one storage container (such as container 102) via the combined conduit 116. For example, for each storage container that will directly receive the merged stream, it may include its corresponding pull-down line 105 and / or in-tank spray manifold 107, which are in fluid communication with the combined conduit 116. Additionally or alternatively, the merged stream may enter the storage container, such as 102, and subsequently, preferably, be distributed to other storage containers via existing infrastructure on the vessel 100 for normal operations other than blending. Preferably, the flow rates of the LNG and ethane streams provide suitable force to move the merged stream to the blended product storage device 102 via appropriate pumps, without requiring additional pumping equipment.

[0036] The conduit network may include multiple valves as known to those skilled in the art to control the flow of various streams. For example, see Figure 1 Optionally, LNG conduit 110 may include valves (not shown) to control the flow of a first LNG stream from storage container 102 to LNG-ethane mixing point 108. Ethane conduit 112 may include a series of valves (not shown) to control the flow of liquefied hydrocarbons from container 114 to LNG-ethane mixing point 108. Combined conduit 116 includes a final valve, which is the last valve the combined stream passes through before reaching its destination, such as container 102, pull-down line 105, and / or spray manifold 107. Figures 1 to 4As shown, the final valve for the combined conduit 116 is final valve 126. For embodiments employing a pull-down line 105 and / or a spray manifold 107 to provide the combined flow from the combined conduit 116 to the container 102, each of the pull-down line 105 and the spray manifold 107 includes its respective final valve (not shown) immediately upstream of the outlet.

[0037] At least when the first LNG stream and the liquefied ethane stream are continuously merged at the blending point 108 and continuously supplied back to the LNG storage container 102, the combined conduit 116 has an operating pressure, at least due to the flow of the merged stream through the combined conduit 116 and the forces exerted by any available flow control devices (such as the final valve 126) within the conduit. When the merged stream is supplied back to the LNG storage container 102, the operating pressure in the combined conduit 116 between the LNG-ethane blending point 108 and the final valve 126 is at a pressure higher than the saturation pressure of the merged stream, preferably at least 0.1 bar higher, more preferably at least 0.5 bar higher, and most preferably at least 1.2 bar higher. An operating pressure at least 1.2 bar higher than the saturation pressure of the merged stream is most preferred because it provides the best buffer to accommodate fluctuations in pressure conditions along the conduit 116, and optionally along the underground pull line 105 and / or the spray manifold 107, but embodiments with a lower operating pressure higher than the saturation pressure of the merged stream can still provide the benefits described herein. The saturation pressure of the merged flow can change as it travels through conduit 116 back to storage container 102, at least due to heat transfer from the environment and / or equipment. Typically, the saturation pressure of the merged flow increases as it travels through the combined conduit 116 toward container 102. Preferably, in response to monitoring, the operating pressure of the combined conduit 116 between the LNG-ethane blending point 108 and the final valve 126 is frequently adjusted to accommodate increases in saturation pressure, and / or the saturation pressure of the merged flow can be reduced to ensure that the operating pressure remains above the saturation pressure of the merged flow when the saturation pressure changes. In addition to other benefits described elsewhere in this disclosure, the method described herein mitigates the formation of two-phase flow (whether localized or continuous) in this portion of the combined conduit 116 by providing an operating pressure above the saturation pressure of the merged flow in the section of the combined conduit 116 between the blending point 108 and the final valve 126. Therefore, as those skilled in the art will appreciate, the method described herein can minimize operational disturbances and equipment damage (e.g., cavitation-driven corrosion of valves). The term "saturation pressure" has its general meaning and includes the definition of pressure when a fluid exists as both vapor and liquid, and where, for a given temperature, the evaporation rate equals its condensation rate. In this context, the saturation pressure of the combined flow is the pressure at which the combined flow presents both gaseous and liquid phases at the temperature of the combined flow. In the combined conduit 116 between the LNG-ethane blending point 108 and the final valve 126, a person skilled in the art can appropriately determine the saturation pressure of the combined flow based on the temperature and blending ratio of the combined flow (both of which can be measured by sensors). The conduit network may include suitable sensors known to a person skilled in the art to provide relevant data to implement the methods described herein.Examples of suitable sensors include hydrometers, gravity meters, densitometers, density measurement sensors, gravity measurement sensors, pressure transducers, temperature sensors, flow meters, mass flow meters, Coriolis flow meters, other measuring sensors for determining density, gravity, or other variables that a person skilled in the art will understand, or some combination thereof. The determination of the saturation pressure of the merged flow can be done manually or autonomously using a computer or other similar process control system, allowing subsequent corrective actions (e.g., increasing the system operating pressure, increasing the blending ratio, or others) to be implemented as needed. The method described herein provides an operating pressure in the combined conduit 116 between the LNG-ethane blending point 108 and the final valve 126 that is higher than the saturation pressure of the merged flow, preferably at least 0.1 bar higher, more preferably at least 0.5 bar higher, and most preferably at least 1.2 bar higher. Providing such an operating pressure higher than the saturation pressure of the merged flow allows the merged flow to remain in the liquid phase as it flows through these conduit sections, regardless of changes in pressure conditions along such conduit sections.

[0038] Suitablely, as known to those skilled in the art, the operating pressure of the merged flow in the combined conduit and other parts of the conduit network can be monitored, such as by means of sensors. Monitoring can allow continuous monitoring of the operating conditions of the merged flow to ensure that the operating pressure in the combined conduit 116 remains above the saturation pressure of the merged flow (preferably at least 0.1 bar, 0.5 bar, or 1.2 bar higher). Optionally and preferably, the operating pressure of the merged flow upstream of the final valve 126, above the saturation pressure of the merged flow, can be provided by adjusting the opening percentage of the final valve 126 to provide the desired operating pressure upstream of valve 126. The opening percentage of the final valve 126 can be continuously adjusted as needed during blending operations to provide the desired operating pressure at or above the saturation pressure of the merged flow as described herein.

[0039] Optionally, additionally, or alternatively, the operating pressure of the combined flow 116 may also be affected by the operating conditions of the downstream system, such as the adjustment of the operating pressure of the storage container (such as 102 or one or more containers (not shown)), including the adjustment of the pressure setpoint of the corresponding evaporative gas management system pressure setpoint, as understood by a person skilled in the art.

[0040] Optionally, additionally, or alternatively, the saturation pressure of the merged stream can be reduced by adjusting the volume ratio of the first LNG stream to liquefied ethane at the LNG-ethane blending point 108 and / or by providing an additional blending point along the combined conduit 116. Generally, the additional blending point allows more LNG to be added to the merged stream, which lowers the saturation pressure of the merged stream, thus providing another option to ensure that the operating pressure of the merged stream is higher than its saturation pressure. See, for example, [link to relevant documentation]. Figure 2The combined conduit 116 also includes a subsequent blending point 208 located upstream of the final valve 126 and downstream of the LNG-ethane blending point 108. For example... Figure 2 As can be seen, the conduit network also includes another conduit segment 216 (which, in a preferred embodiment, may be referred to as the second LNG conduit 216) to provide storage container 102 (or a second suitable source of LNG, which is not in Figure 2 The second LNG conduit 216 (as depicted in the diagram) provides fluid communication between the subsequent blending point 208 and the storage container 102. When the second LNG flow originates from the storage container 102, the second LNG conduit 216 can provide fluid communication between the subsequent blending point 208 and the storage container 102 via a connection to the LNG conduit 110 or another conduit segment (not shown) providing fluid communication between the storage container 102 and the conduit 216. When needed, a second flow of the first liquefied hydrocarbon (preferably LNG) can be provided from the storage container 102 (or a second source of LNG) via the second LNG conduit 216 to the subsequent blending point 208. Optionally and preferably, the second LNG conduit 216 may also include a valve 222 to control the flow of the second LNG through the second LNG conduit 216. For example, the valve 222 can be closed when blending at the subsequent blending point 208 is not required, and can be opened when additional LNG needs to be blended into the combined flow. The opening of the valve 222 can be adjusted to achieve the desired blending ratio at the subsequent blending point 208. Figure 2 In this process, the merged stream and the second LNG stream are merged at a subsequent blending point 208 at a ratio of 25:1, preferably 50:1, and up to a maximum of 500:1, and the first LNG stream and the ethane stream are merged at the LNG-ethane blending point 108 at a ratio of 1:100 and up to a maximum of 50:1. Because an additional blending point is provided, the LNG to ethane ratio at the LNG-ethane blending point 108 can be less than in the case where only a single blending point exists (i.e., 108). For example, in a single blending point scenario, the LNG to ethane ratio at the LNG-ethane blending point is in the range of 1:500 and up to a maximum of 500:1, while in... Figure 2 In the depicted multi-blending-point scenario, the LNG to ethane ratio at LNG-ethane blending point 108 is in the range of 1:500, preferably 1:100, and up to 50:1, and the ratio of the merged stream to the second LNG stream at the subsequent blending point 208 is in the range of 25:1, preferably 50:1, and up to 500:1. As will be understood by those skilled in the art, the provided blending ratio range for multi-blending-point scenarios can be extended or changed to suit asset and / or process-specific requirements. For example, the first blending point may have a blending ratio of 1:1, while the second blending point may have a blending ratio of 47:1.

[0041] Optionally, additionally, or alternatively, different blending points may exist downstream of the final valve 126. For example, see Figure 3 The combined conduit 116 also includes a subsequent blending point 308 located downstream of the final valve 126 and upstream of the container 102. Optionally and alternatively, the subsequent blending point 308 may be located upstream of the final valve 126, depending on the specific layout of the existing infrastructure of the plant where the blending operation is performed. Figure 3 As can be seen, the conduit network also includes a third LNG conduit 316 to provide fluid communication between the first source of liquefied hydrocarbons (such as LNG), which may be the depicted storage container 102 or another suitable source not shown, and the subsequent blending point 308. Another LNG stream can be provided to the subsequent blending point 308 when needed. As shown, conduit 316 may also include a valve to control the flow of LNG through it. Figure 3 In the process, the merged stream and the LNG stream from conduit 316 are merged at a subsequent blending point 208 at a ratio of 25:1, preferably 50:1, and up to 500:1, and the first LNG stream and the ethane stream are merged at the LNG-ethane blending point 108 at a ratio of preferably 25:1, preferably 50:1, and up to 500:1. For Figure 3 In the multi-blending scenario depicted, the blending ratio of LNG to ethane at LNG-ethane blending point 108 is in the range of 1:500, preferably 1:100 and up to 50:1, and at the subsequent blending point 308, the ratio of the combined flow to the LNG flow from conduit 316 is in the range of 25:1, preferably 50:1 and up to 500:1.

[0042] Optionally, additionally, or alternatively, two additional blending points may coexist with LNG-ethane blending point 108. For example, see Figure 4 The combined catheter 116 includes, respectively, as follows: Figure 2 and Figure 3 The subsequent blending points 208 and 308 described in [the text]. For Figure 4 The multi-blending point scenario depicted includes: (i) at LNG-ethane blending point 108, the LNG to ethane blending ratio is in the range of 1:500, preferably 1:100, and up to 50:1; (ii) at subsequent blending point 208, the blending ratio of the merged stream to the second LNG stream is in the range of 25:1, preferably 50:1, and up to 150:1; and (iii) at subsequent blending point 308, the blending ratio of the merged stream to the LNG stream from conduit 316 is in the range of 100:1, preferably 150:1, and up to 500:1. Although not shown, it should be understood that additional blending points and opportunities may exist on an asset basis, although not specified in the provided figures.

[0043] Optionally and preferably, various blending scenarios (such as single or multiple blending points) and blending ratios within the provided range can be selected to achieve a volumetric blending ratio of at least 2:1, preferably at least 3:1, and more preferably at least 4:1 of LNG to ethane in the merged stream downstream of the final valve 126 (for scenarios involving a single blending point and / or multiple blending points with a subsequent blending point 208) or downstream of the subsequent blending point 308 (for scenarios including blending point 308).

[0044] It should be understood that a BOG management system (not shown) for vessel 100 can exist in all figures. In the case of vessel-to-vehicle operations at a dock, as is known to those skilled in the art, this can be an onboard system or a land-based BOG management system.

[0045] Optionally and preferably, a first LNG stream is pumped to the LNG-ethane blending point 108 at a certain volumetric flow rate and pressure, which can be adjusted throughout the blending operation to meet relevant process requirements. Although the flow rate and pressure of the first LNG stream pumped to the blending point 108 can be adjusted, it is preferred to minimize the rate of change of the first LNG stream during operation to a reasonable and / or practical extent. Meanwhile, as known to those skilled in the art, the volumetric flow rate and pressure of the liquefied ethane stream in the ethane conduit 112 can be appropriately adjusted to meet the desired blending ratio at the LNG-ethane blending point 108, where, for a single blending point, the LNG to liquefied ethane blending ratio is in the range of 1:500, preferably 1:100 to 500:1, or, in scenarios including multiple blending points as described herein, within a range of various blending ratios at other blending points.

[0046] The embodiments described in this disclosure provide options for implementation, such as choosing between single-point blending operation or a multi-point process, to allow various factors to be considered when optimizing the blending operation as needed. For example, at facilities with hydraulic constraints in the conduit section upstream of the first blending point 108 (e.g., at least a portion of the conduit 110 leading to the first blending point has a reduced inner diameter, such as 12 inches or less, or smaller than the diameter of conduits 116 and / or 112). Multi-point blending operation may be more suitable for such situations because such constraints limit single-point blending operation, such as in terms of flow rate and blending ratio possibilities (including a reduction in the amount of second liquefied hydrocarbon that can be blended) and higher operating costs. Additionally, multi-point blending operation allows for improved control and flexibility of the overall operation.

[0047] See Figures 1 to 4The combined conduit 116 continues through the final valve 126 to provide a combined flow (which may originate from a single or multiple blending point) to the container 102 downstream of the final valve 126. The conduit segment associated with the final valve 126 and the outlets of the pull-down line 105 and the in-tank spray manifold 107 has a certain length, shape, and dimensions (such as diameter) and may include… Figures 1 to 4 Flow control devices not depicted herein may be used to help determine specific operating parameters that should be considered. Optionally, additionally, or alternatively, the operating pressure of storage container 102 is another potential consideration, as noted elsewhere in this disclosure. Optionally and preferably, the operating pressure of the merged flow downstream of final valve 126 can be influenced by manipulating the operating pressure of the corresponding storage container 102. Suitable methods for manipulating the operating pressure of the storage containers are known to those skilled in the art, such as by adjusting the pressure setpoint of the associated BOG management system.

[0048] Optionally, the blending operation can be further improved, such as by reducing the time required to complete the blending operation, by providing an operating pressure higher than the saturation pressure of the merged flow to the receiving storage container (the storage container to which the merged flow is supplied, such as container 102). It should be understood that the higher operating pressure is limited by the safety operating parameters of the respective storage container. Preferably, the operating pressure of the receiving container is at least 5% higher than the saturation pressure of the merged flow, more preferably at least 50%, and most preferably at least 100%. A suitable way to provide such containers with an operating pressure higher than the saturation pressure of the merged flow is to adjust the BOG pressure setpoint as known to those skilled in the art.

[0049] The option of providing a receiving storage container with an operating pressure higher than the saturation pressure of the merged stream is limited by the safety operating parameters of the respective storage container, is not typical in standard operating practices for these tanks (primarily for storing liquefied hydrocarbons for transport), and can be implemented as needed. If adopted, a higher operating pressure is temporarily provided to the respective storage container for part or all of the blending operation duration, or even maintained as needed after the blending operation.

[0050] Generally, for storage, it is desirable to maintain relatively low operating pressures, preferably as low as possible within applicable technical and contractual constraints, to keep the temperature of the product in the storage container correspondingly low, thereby optimizing the volumetric capacity of the storage container and reducing BOG formation. Lower operating pressures are more desirable in the long term as they help minimize changes in LNG quality over time. It should be understood that the standard practice of maintaining low operating pressures on receiving storage tanks is also an option to be chosen during partial or full blending operations. The desired operating pressure for a particular receiving tank is achieved primarily by managing the BOG of the respective tank, typically through an associated BOG management system. By providing higher operating pressures to the applicable storage containers during blending operations, flashing of the merged stream upon entering the respective storage containers is reduced or even potentially eliminated, thereby minimizing or even eliminating the evaporation gas formation rate associated with blending operations. Minimizing or eliminating the BOG formation rate during blending operations relaxes constraints on evaporation gas management, which reduces operating time. Once blending operations are complete, the operating pressure of the respective tank can be reduced to return it to standard operating pressure, or optionally maintained in accordance with the applicable technical and contractual constraints imposed on the vessel and its cargo. After the blending operation, standard operating procedures can be used to manage the BOG, allowing the blending operation to be performed without any time delay associated with BOG management.

[0051] The method disclosed herein addresses certain negative effects of in-tank blending of two different liquefied hydrocarbons, such as stratification, by promoting online blending of the two different liquefied hydrocarbons in a conduit at an operating pressure above the saturation pressure of the merged stream. Because the saturation pressure of the merged stream can vary throughout its journey from blending point 108 to its destination (such as return to container 102), references to “saturation pressure of the merged stream” are generally made in the context of a specific section of the conduit. Adjusting the blending ratio and / or providing an additional blending point, as described herein, are suitable ways to manipulate the operating pressure of relevant sections of the conduit and / or influence the saturation pressure of the merged stream in those sections to achieve desired operating pressure levels above the saturation pressure of the merged stream, comfortably ensuring its liquefaction.

[0052] Additionally, the method described herein provides an option to minimize BOG management requirements during blending operations by providing an operating pressure higher than the saturation pressure of the merged stream to the respective receiving storage container, thereby minimizing flash evaporation when the merged stream enters the respective storage container and thus reducing the operation time of the blending operation.

[0053] As noted in this disclosure, the methods described herein can be used for blending operations of two liquefied hydrocarbon streams, such as LNG and liquefied ethane, particularly at existing facilities using infrastructure already used for standard operations, such as loading and storage equipment. For example, if the goal is to produce “rich” LNG to meet the requirements of a specific end market or application, the methods described herein can be used to add liquefied ethane (or another lighter hydrocarbon or a combination of light hydrocarbons) to LNG from an LNG carrier, utilizing the combined infrastructure of both the first and second vessels (such as pumps, conduits, valves, control systems, vapor gas management systems, etc.), and in some embodiments, the infrastructure of the terminal at an LNG import or export facility. It is known to those skilled in the art that an LNG carrier can be represented by an LNG vessel (barge or ocean-going vessel) or an LNG FSRU, or an LNG import facility can also be represented by an LNG FSRU, or an LNG export facility can also be represented by an LNG floating and production facility. When blending operations are required, certain operating parameters of the facility can be modified to achieve the methods described herein.

[0054] During standard operation, the LNG floating facility operates under its standard parameters to handle its LNG cargo and cargo management operations, such as vapor gas management. Prior to the start of blending operations, the product in storage container 102 is typically lean LNG, which can be further enriched with another liquefied hydrocarbon. Before merging the lean LNG with another liquefied hydrocarbon (such as ethane), the lean LNG from storage container 102 is preferably recirculated on LNG vessel conduit 110 and returned to tank 102 as part of standard loading / unloading operations or other operations, allowing the conduit cooling procedure to minimize the temperature difference between the merged stream and the conduit. A greater temperature difference has a greater negative impact on the blending operation, including vapor formation. Similar recirculation of the second liquefied hydrocarbon (such as ethane) is also preferably carried out on the second vessel 104 to prepare for cargo transfer and blending operations. Before providing the second liquefied hydrocarbon stream to the first blending point 108, the lean LNG from storage container 102 is preferably first provided to blending point 108 and returned to container 102 via conduit 116 to ensure cooling of at least the blending path of the merged stream. The circulation of the various applicable flows described can be achieved by various pump devices as known to those skilled in the art, such as pump 120 (or other pumps on LNG ships, and...) Figures 1 to 4 (Not depicted herein) and 120 are appropriately facilitated. After establishing the circulation of the first liquefied hydrocarbon, a second liquefied hydrocarbon stream can be pumped from the second container 114 to initiate blending operations, according to the aspects described herein. According to the aspects described herein, the merged stream is provided back to the storage container 102, including providing it to the container 102 at an operating pressure higher than the saturation pressure of the merged stream.

[0055] Compared to standard operating parameters, the operating parameters of the blending operation, as described herein, affect the operating pressure of the conduit network. Optionally and preferably, the conduit network is provided with an operating pressure of at least 2 bar g (bar gauge pressure) to accommodate the effects from the blending operation while meeting the operating parameters. Suitable methods for providing such operating pressure to the conduit network are known to those skilled in the art. Once the blending operation is complete, such as when storage container 102 reaches the desired specifications, the liquefied ethane flow is ramped down and stopped. Resumption of standard operation includes returning the operating pressure of the conduit network to its standard parameters. For embodiments in which the operating pressure of a corresponding storage container (such as 102) has increased above the saturation pressure of the merged flow, the operating pressure of the corresponding container is also reduced to its standard parameters. After the blending operation, the blended product in container 102 can be stored as inventory or otherwise managed, such as being allocated according to contractual obligations.

[0056] The methods described herein can be carried out continuously over a period of time until the blended product in container 102 has the desired specifications, such as a specific calorific value, and / or a desired amount of a second liquefied hydrocarbon, such as liquefied ethane, has been blended. During or after the blending operation, the characteristics of the product in container 102 can be monitored according to the facility's standard operating procedures to determine whether the desired specifications have been achieved. It should be understood that the vessels (100 and 104) may include multiple storage containers (102 and 114, respectively), and embodiments of the methods described herein can be used for various combinations of such storage containers on these vessels.

[0057] In applications where the merged stream can be recycled or distributed among various storage tanks (not shown) on vessel 100 so that at least a portion (including all) of the merged stream is supplied to the blending point (as if it were lean LNG), the accumulation of a second liquefied hydrocarbon (such as liquefied ethane) may occur. That is, when blending operations have been performed for a period of time, the first liquefied hydrocarbon stream pumped to the first blending point 108 contains an amount of second liquefied hydrocarbon that increases over time. Such accumulation can be addressed by adjusting the blending ratio at the LNG-ethane blending point 108. LNG floating facilities typically include equipment for continuously monitoring the characteristics of the LNG flowing through the conduit network, including sensors (e.g., flow rate). Continuous monitoring allows for continuous adjustment of the flow rate of the corresponding stream (preferably the liquefied ethane stream) to achieve the desired blending ratio.

[0058] Optionally and preferably, the flow of the merging flow in a portion of the combined conduit 116 upstream of the final valve 126 is preferably carried out in a turbulent state.

[0059] The method presented herein (which involves the online mixing of a first LNG stream and a liquefied ethane stream, particularly under turbulent conditions) maximizes the mixing of LNG and liquefied ethane in the merged stream, thereby enabling the merged stream to exhibit a homogeneous composition and characteristics (e.g., density) so that it can be supplied to the blended product storage container 102 under homogeneous conditions. This mitigates the risks associated with stratified flow entering the storage container. However, due to the difference in specific enthalpy between lean LNG and liquid ethane streams, online blending operations can introduce partial vaporization and the formation of a two-phase flow, which can lead to the risk of undesirable excessive pipeline vibration, resulting in pipeline stress and fatigue. The method described herein addresses the potential for two-phase flow formation by maintaining the operating pressure in the merged stream above the merged stream saturation pressure.

[0060] Although not shown, it should be understood that some (including all) aspects of the methods described herein can be controlled and / or implemented using a computer program. This computer program may be referred to as a controller. For example, a computer program can control the discharge pressure and flow rate of a pump, control the system's operating pressure by manipulating the percentage opening of a flow control valve, etc. Suitable computer programs include those executed by a data processor. As used herein, references to computer programs are intended to be equivalent to references to program elements and / or computer-readable media containing instructions for controlling a computer system to coordinate the performance of the methods described above. Computer programs can be implemented as computer-readable instruction code using any suitable programming language (such as, for example, JAVA, C++) and can be stored on computer-readable media (removable disks, volatile or non-volatile memory, embedded memory / processors, etc.). The instruction code is operable to program a computer or any other programmable device to perform the intended function. Computer programs are available from networks (such as the World Wide Web) and can be downloaded from such networks. The various aspects described herein can be implemented separately in software using computer programs; however, they can also be implemented separately in hardware using one or more specific electronic circuits. Furthermore, the present invention can also be implemented in a hybrid form, that is, by combining software modules and hardware modules. Additionally or alternatively, any or all aspects of the methods described herein can be performed manually by one or more operators with relevant operational knowledge of the facility.

[0061] While specific embodiments have been described herein, it should be understood that such description is not intended to limit the described embodiments. Rather, any combination of the features and elements provided above (whether or not different embodiments are involved) is contemplated for implementing and practicing the contemplated embodiments. Furthermore, although the embodiments disclosed herein may achieve advantages over other possible solutions or over the prior art, whether a particular advantage is achieved by a given embodiment does not limit the scope of the invention. Therefore, the aspects, features, embodiments, and advantages described herein are merely illustrative and should not be considered as elements or limitations of the appended claims unless expressly recited in the claims.

Claims

1. A method for blending two or more streams of liquefied hydrocarbons between at least two vessels, wherein a first vessel (100) includes a first storage container (102) for storing a first liquefied hydrocarbon, optionally the first liquefied hydrocarbon being liquefied natural gas, and wherein a second vessel (104) includes a second storage container (114) for storing a second liquefied hydrocarbon, optionally the second liquefied hydrocarbon being selected from the group consisting of liquefied ethane, liquefied butane, liquefied propane, and any combination thereof, wherein the method comprises: (a) Providing a conduit network between the at least two vessels, wherein the conduit network comprises: i. First blending point (108), optionally wherein the first blending point is part of the liquid manifold of the second vessel 104, ii. A first conduit segment (110), optionally wherein the first conduit segment is part of the liquid manifold of the first vessel to provide fluid communication between the first storage container (102) and the first mixing point (108), iii. A second conduit segment (112) providing fluid communication between the second storage container (114) and the first mixing point (108), wherein optionally the second conduit segment is part of the liquid manifold of the second vessel; iv. A combination conduit (116) providing fluid communication downstream of the first blending point (108) and back to the inlet of the first storage container (102), wherein the combination conduit (116) includes a final valve (126) immediately upstream of the inlet of the first storage container. The method includes: (b) Pumping the first liquefied hydrocarbon stream from the first storage container (102) via the first conduit segment (110) to the first blending point (108); (c) Pumping the second liquefied hydrocarbon stream from the second storage container (114) via the second conduit section (112) to the first blending point (108); (d) At the first blending point (108), the first liquefied hydrocarbon stream and the second liquefied hydrocarbon stream are combined at a volume ratio of 1:500, preferably 1:100, and up to 500:1 to provide a combined stream; and (e) Providing at least a portion, including all, of the combined stream from the first blending point (108) back to the first storage container (102) via the combined conduit (116), thereby providing the combined product to the first storage container, and (f) When the merged flow is located between the segments of the combined conduit (116) between the first blending point (108) and the final valve (126), the merged flow is supplied with an operating pressure higher than the saturation pressure of the merged flow (preferably at least 0.1 bar higher, more preferably at least 0.5 bar higher, and most preferably at least 1.2 bar higher).

2. The method of claim 1, wherein the combined conduit (116) further comprises a first subsequent blending point (208) downstream of the first blending point (108) and optionally upstream of the final valve 126, wherein the method further comprises: (g) A second stream of the first liquefied hydrocarbon is provided from the source of the first liquefied hydrocarbon, optionally the first storage container (102), to the first subsequent blending point (208). (h) At the first subsequent blending point (208), the combined stream and the second stream of the first liquefied hydrocarbon are combined at a volume ratio of 25:1, preferably 50:1 and up to 500:1, wherein the first stream of the first liquefied hydrocarbon and the second liquefied hydrocarbon ethane stream are combined at the first blending point (108) at a volume ratio of 1:500, preferably 1:100 and up to 50:

1.

3. The method of claim 2, wherein the combined conduit (116) further comprises a second subsequent blending point (308), the second subsequent blending point being located downstream of the first subsequent blending point (208), upstream or downstream of the final valve (126), and upstream of the inlet of the first storage container (102), wherein the method comprises: (i) A third stream of the first liquefied hydrocarbon is provided from the source of the first liquefied hydrocarbon, optionally the first storage container (102), to the second subsequent blending point (208). (j) The merged stream and the third stream of the first liquefied hydrocarbon are combined at the second subsequent blending point (308) at a volume ratio of 25:1, preferably 50:1 and up to 150:1, wherein the first liquefied hydrocarbon stream and the second liquefied hydrocarbon stream are combined at the first blending point (108) at a volume ratio of 1:500, preferably 1:100 and up to 50:1, and wherein the merged stream and the second stream of the first liquefied hydrocarbon are combined at the first subsequent blending point (208) at a volume ratio of 100:1, preferably 150:1 and up to 500:

1.

4. The method of claim 1, wherein the combined conduit (116) further comprises a subsequent blending point (308) located downstream of the final valve (126) and upstream of the inlet of the first storage container (102), wherein the method comprises: (g) Providing another stream of the first liquefied hydrocarbon from the source of the first liquefied hydrocarbon to the subsequent blending point (308), optionally wherein the source is the first storage container (102). (h) At the subsequent blending point (308), the merged stream and the other stream of the first liquefied hydrocarbon are combined at a volume ratio in the range of 25:1, preferably 50:1 and up to 500:1, and wherein the first stream of the first liquefied hydrocarbon and the stream of the second liquefied hydrocarbon are combined at the first blending point (108) at a volume ratio in the range of 1:500, preferably 1:100 and up to 50:

1.

5. The method according to any of the preceding claims, wherein the combined stream downstream of the final valve (126) and downstream of any subsequent blending point (308) has a volume ratio of the first liquefied hydrocarbon, preferably LNG, to the second liquefied hydrocarbon, preferably liquefied ethane, of at least 2:1, preferably at least 3:1, and more preferably at least 4:

1.

6. The method according to any of the preceding claims, wherein the conduit network further comprises at least one of a pull-down line (105) and an in-tank spray manifold (107) to introduce the combined flow from the combined conduit 116 into the first storage tank (102).

7. The method according to any of the preceding claims, wherein the pull-down line (105) and / or the in-tank spray manifold (107) further comprises its respective final valve immediately upstream of its outlet, wherein the method further comprises providing an operating pressure to the conduit segment between the combined conduit and the respective final valve of the pull-down line and / or the in-tank spray manifold that is higher than the saturation pressure of the combined flow (preferably at least 0.1 bar higher, more preferably at least 0.5 bar higher, and most preferably at least 1.2 bar higher).

8. The method according to any of the preceding claims, further comprising: Provide a total operating pressure of at least 2 bar to the catheter network.

9. The method according to any of the preceding claims, further comprising: The first storage container (102) is supplied with an operating pressure that is higher than the saturation pressure of the combined flow (preferably at least 5%, more preferably at least 50%, and most preferably at least 100%) than the saturation pressure of the combined flow.

10. The method according to any of the preceding claims, further comprising: Steps (a)-(e) are performed consecutively, and, where applicable, steps (f)-(h) are performed consecutively, until the desired amounts of the first liquefied hydrocarbon and / or the second liquefied hydrocarbon have been combined.

11. The method of claim 10, further comprising: The operating pressure of the conduit network is returned to the standard operating pressure, and the operating pressure of the first storage container (102) is returned to the standard operating pressure.

12. The method according to any of the preceding claims, further comprising: The combined product is supplied from the first storage container (102) to another storage container on the first vessel.

13. The method according to any of the preceding claims, further comprising: The combined product is stored as a library in the first storage container (102).

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