AU2022339868A1 - Formed plate core-in-shell and multi-pass exchangers - Google Patents

Abstract

A core-in-shell heat exchanger including a shell having an interior shell portion operable to receive a cooling fluid therein and at least one formed plate heat exchanger (FPHE) core operably arranged within the interior shell portion. The FPHE core includes an inlet coupled with a feed stream, a plurality of feed layers fluidly coupled with the inlet, and a plurality of cooling layers fluidly coupled with the interior shell portion and operable to receive at least a portion of the cooling fluid therein.

Description

FORMED PLATE CORE-IN-SHELL AND MULTI-PASS EXCHANGERS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to U.S. Provisional Application 63/240,142 filed on September 2, 2021 , which is incorporated by reference in its entirety herein.

FIELD

[0002] The presently disclosed technology relates generally to Formed Plate Heat Exchangers (FPHE) in core-in-shell applications.

BACKGROUND

[0003] Core-in-shell heat exchangers currently utilize brazed aluminum heat exchanger (BAHX) cores disposed within an interior space of a shell. The shell is typically formed of a carbon steel, stainless steel, or similar material, thereby requiring the implementation of a transition joint between the shell and the brazed aluminum heat exchanger core. BAHX cores have no endurance limit and are more susceptible to fatigue failures than other types of exchangers. Transition joints are another source of potential leaks. It is with these observations in mind, among others, that various aspects of the present disclosure were conceived and developed.

SUMMARY

[0004] Implementations described herein address the foregoing by providing systems, methods, and apparatuses to implement a Formed Plate Heat Exchanger (FPHE) with a core-in-shell exchanger. A stainless steel FPHE implemented within a core-in-shell heat exchanger can eliminate the need for transition joints and/or flanges between the core(s) and the shell.

[0005] In one implementation, a core-in-shell heat exchanger includes a shell having an interior portion operable to receive a cooling fluid therein and one or more FPHE core(s) operably arranged within the interior portion. The FPHE core(s) can include an inlet or inlets coupled with a feed stream or feed streams, a plurality of feed layers fluidly coupled with the inlet, a plurality of cooling layers fluidly coupled with the interior portion and operable to receive at least a portion of the cooling fluid therein.

[0006] The vessel shell can be formed from an iron-based alloy and the FPHE core can be formed of an iron-based alloy and the FPHE core(s) can be coupled directly with the shell. The shell and/or the FPHE core(s) are formed of stainless steel, titanium, Invar, and/or a nickel-iron alloy.

[0007] The plurality of feed layers and/or the plurality of cooling layers in the FPHE core can be diffusion bonded, forming a metallurgic bond there between.

[0008] Each of the plurality of feed layers can include a plurality of fins of various geometries forming a feed stream flow path therethrough and each of the plurality of cooling layers includes a plurality of fins forming a cooling flow path therethrough.

[0009] The FPHE core can be a multi-pass heat exchanger including one or more separators coupled with the plurality of feed layers. In at least one instance, the FPHE can have three separators forming a first plurality of feed layers, a second plurality of feed layers, and a third plurality of feed layers arranged serially.

[0010] The core-in-shell heat exchanger can also include a second, third, fourth or more FPHE core(s) operably arranged within the interior portion. The additional FPHE core(s) can include an additional inlet(s) coupled with feed stream, a plurality of additional feed layers fluidly coupled with the additional inlet, and a plurality of additional cooling layers fluidly coupled with the interior portion and operable to receive at least a portion of the cooling fluid therein. The FPHE core and/or the additional FPHE core(s) can be fluidically isolated one from the other.

[0011] The cooling fluid within the shell and operably received in a portion of the FPHE core and/or the second FPHE core can be one of propane, propylene, methane, ethane, ethylene, a mixture of hydrocarbons, and/or any other common refrigerant or mixture of refrigerants. [0012] In one implementation, a liquefied natural gas (LNG) system includes a gas feed stream and a core-in-shell heat exchanger having an inlet coupled with the gas feed stream. The core-in-shell heat exchanger can include a shell having an interior portion operable to receive a cooling fluid therein. A formed plate heat exchanger (FPHE) core or cores operably arranged within the interior portion and disposed within at least a portion of the cooling fluid. The FPHE core or cores having a plurality of feed layers fluidly coupled with the inlet and operable to receive the gas feed stream therein and a plurality of cooling layers operable to receive at least a portion of the cooling fluid therein. The plurality of feed layers has an outlet separated from the inlet by a fluid flow path.

[0013] The LNG system can also include a second core-in-shell heat exchanger having an inlet coupled with the outlet of the FPHE core of the core-in-shell heat exchanger. The second core-in-shell heat exchanger having a shell having an interior portion operable to receive a second cooling fluid therein and a formed plate heat exchanger (FPHE) core operably arranged within the interior portion and disposed within at least a portion of the second cooling fluid. The FPHE core having a plurality of feed layers fluidly coupled with the inlet and operable to receive an outlet stream of the core-in-shell heat exchanger and a plurality of cooling layers operable to receive at least a portion of the second cooling fluid therein. The plurality of feed layers has an outlet separated from the inlet by a fluid flow path.

[0014] The LNG system can also include a third, fourth or plurality of core-in-shell heat exchanger(s) having an inlet or inlets coupled with the outlet or outlets of the FPHE core(s) of the second core-in-shell heat exchanger. The third, fourth or plurality of core-in-shell heat exchanger(s) can include a shell having an interior portion operable to receive a third, fourth, or plurality of cooling fluid(s) therein and one or more formed plate heat exchanger (FPHE) core(s) operably arranged within the interior portion and disposed within at least a portion of the third, fourth, or plurality of cooling fluid(s). The FPHE core(s) having a plurality of feed layers fluidly coupled with the inlet(s) and operable to receive an outlet stream or outlet streams of the second core-in-shell heat exchanger and a plurality of cooling layers operable to receive at least a portion of the third cooling fluid therein. The plurality of feed layers has an outlet separated from the inlet by a fluid flow path.

[0015] The outlet(s) of at least one of the first core-in-shell heat exchanger, the second core-in-shell heat exchanger, the third core-in-shell heat exchanger, and/or one or more of a plurality of core-in-shell heat exchangers can be operably arranged to produce a liquefied gas stream. The first cooling fluid, the second cooling fluid, and/or the third cooling fluid are at least of propane, propylene, methane, ethane, ethylene, a mixture of hydrocarbons, and/or any other common refrigerant or mixture of refrigerants. The shell is formed from an iron-based alloy and the FPHE core is formed of an iron-based alloy, the FPHE core coupled directly with the shell. The shell and/or the FPHE core can be formed of formed of stainless steel, titanium, Invar, and/or a nickel-iron alloy.

[0016] The FPHE core of one or more of the first core-in-shell heat exchanger, the second core-in-shell heat exchanger, and/or the third core-in-shell heat exchanger includes one or more separators coupled with the plurality of feed layers. In at least one instance, the FPHE core of one or more of the first core-in-shell heat exchanger, the second core-in-shell heat exchanger, and/or the third core-in-shell heat exchanger includes can have three separators forming a first plurality of feed layers, a second plurality of feed layers, and a third plurality of feed layers arranged serially.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 illustrates an example simplified flow diagram of a cascade refrigeration process with a nitrogen rejection unit;

[0018] FIG. 2 is a diagrammatic view of an example core-in-shell heat exchanger having at least one formed plate heat exchanger (FPHE) core;

[0019] FIG. 3 is a diagrammatic view of an example core construction of an FPHE;

[0020] FIG. 4A is a diagrammatic view of an example multi-pass FPHE core;

[0021] FIG. 4B is a section view of an example multi-pass FPHE core taken along A-A of FIG. 4A; [0022] FIG. 4C is an exploded diagrammatic view of an example FPHE core;

[0023] FIG. 5A is a simplified example of flow patterns that may be used in a heat exchanger core; and

[0024] FIG. 5B provides another example flow pattern that may also be used in a heat exchanger core.

DETAILED DESCRIPTION

[0025] Examples and various features and advantageous details thereof are explained more fully with reference to the exemplary, and therefore non-limiting, examples illustrated in the accompanying drawings and detailed in the following description. Descriptions of known starting materials and processes can be omitted so as not to unnecessarily obscure the disclosure in detail. It should be understood, however, that the detailed description and the specific examples, while indicating the preferred examples, are given by way of illustration only and not by way of limitation. Various substitutions, modifications, additions and/or rearrangements within the spirit and/or scope of the underlying technology will become apparent to those skilled in the art from this disclosure.

I. TERMINOLOGY

[0026] Indirect heat exchange, as used herein, refers to a process involving a cooler stream cooling a substance without actual physical contact between the cooler stream and the substance to be cooled. Specific examples of indirect heat exchange include, but are not limited to, heat exchange undergone in a shell-and-tube heat exchanger and/or a core- in-shell heat exchanger. The specific physical state of the refrigerant and substance to be cooled can vary depending on demands of the refrigeration system and type of heat exchanger chosen. Indirect heat exchange can be implemented with gases, liquids, liquid/vapor mixtures and/or combinations thereof for heat transfer, evaporation, and/or condensation. As used herein, a feed stream and/or warm stream is a gas or liquid stream that is cooled in heat exchange, and a cooling fluid and/or refrigerant is a gas or liquid stream that cools the warm or feed stream in heat exchange.

[0027] As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, product, article, or apparatus that comprises a list of elements is not necessarily limited only those elements but can include other elements not expressly listed or inherent to such process, process, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

[0028] The term “substantially”, as used herein, is defined to be essentially conforming to the particular dimension, shape or other word that substantially modifies, such that the component need not be exact. For example, substantially cylindrical means that the object resembles a cylinder, but can have one or more deviations from a true cylinder.

[0029] Additionally, any examples or illustrations given herein are not to be regarded in any way as restrictions on, limits to, or express definitions of, any term or terms with which they are utilized. Instead these examples or illustrations are to be regarded as being described with respect to one particular example and as illustrative only. Those of ordinary skill in the art will appreciate that any term or terms with which these examples or illustrations are utilized encompass other examples as well as implementations and adaptations thereof which can or cannot be given therewith or elsewhere in the specification and all such examples are intended to be included within the scope of that term orterms. Language designating such non-limiting examples and illustrations includes, but is not limited to: “for example,” “for instance,” “e.g.,” “In some examples,” and the like.

[0030] Although the terms “first”, “second”, etc. can be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present disclosure.

II. GENERAL ARCHITECTURE

[0031] The systems and methods disclosed herein relate to an implementation of Formed Plate Heat Exchangers (FPHE) for core-in-shell applications, including a multi-pass FPHE, multiple PPHEs (Pillow Plate Heat Exchanger) and/or the like in a core-in-shell application.

[0032] The presently disclosed technology may be implemented in a cascade LNG system employing a cascade-type refrigeration process using one or more predominately pure component refrigerants. The refrigerants utilized in cascade-type refrigeration processes can have successively lower boiling points to facilitate heat removal from the natural gas stream that is being liquefied. Additionally, cascade-type refrigeration processes can include some level of heat integration. For example, a cascade-type refrigeration process can cool one or more refrigerants having a higher volatility through indirect heat exchange with one or more refrigerants having a lower volatility. In addition to cooling the natural gas stream through indirect heat exchange with one or more refrigerants, cascade and mixed- refrigerant LNG systems can employ one or more expansion cooling stages to simultaneously cool the LNG while reducing its pressure.

[0033] In one implementation, the LNG process may employ a cascade-type refrigeration process that uses a plurality of multi-stage cooling cycles, each employing a different refrigerant composition, to sequentially cool the natural gas stream to lower and lower temperatures. For example, a first refrigerant may be used to cool a first refrigeration cycle. A second refrigerant may be used to cool a second refrigeration cycle. A third refrigerant may be used to cool a third refrigeration cycle. Each refrigeration cycle may include a closed cycle or an open cycle. The terms “first”, “second”, and “third” refer to the relative position of a refrigeration cycle. For example, the first refrigeration cycle is positioned just upstream of the second refrigeration cycle while the second refrigeration cycle is positioned upstream of the third refrigeration cycle and so forth. While at least one reference to a cascade LNG process comprising three different refrigerants in three separate refrigeration cycles is made, this is not intended to be limiting. It is recognized that a cascade LNG process involving any number of refrigerants and/or refrigeration cycles may be compatible with one or more implementations of the presently disclosed technology. Other variations to the cascade LNG process are also contemplated. It will also be appreciated that the presently disclosed technology may be utilized in non-cascade LNG processes. One example of a non-cascade LNG process involves a mixed refrigerant LNG process that employs a combination of two or more refrigerants to cool the natural gas stream in at least one cooling cycle.

[0034] To begin a detailed description of an example cascade LNG facility 100 in accordance with the implementations described herein, reference is made to FIG. 1. The LNG facility 100 generally comprises a first refrigeration cycle 30 (such as, a propane refrigeration cycle), a second refrigeration cycle 50 (such as, an ethylene refrigeration cycle), and a third refrigeration cycle 70 (such as, a methane refrigeration cycle) with an expansion section 80. Those skilled in the art will recognize that FIG. 1 is schematic only and, therefore, various equipment, apparatuses, or systems that would be needed in a commercial plant for successful operation have been omitted for clarity. Such components might include, for example, compressor controls, flow and level measurements and corresponding controllers, temperature and pressure controls, pumps, motors, filters, additional heat exchangers, valves, and/or the like. Those skilled in the art will recognize such components and how they are integrated into the systems and methods disclosed herein.

[0035] In one implementation, the main components of the propane refrigeration cycle 30 include a propane compressor 31 , a propane cooler/condenser 32, high-stage propane chillers 33A and 33B, an intermediate-stage propane chiller 34, and a low-stage propane chiller 35. The main components of ethylene refrigeration cycle 50 include an ethylene compressor 51 , an ethylene cooler 52, a high-stage ethylene chiller 53, a low-stage ethylene chiller/condenser 55, and an ethylene economizer 56. The main components of methane refrigeration cycle 70 include a methane compressor 71 , a methane cooler 72, and a methane economizer 73. The main components of expansion section 80 include a high-stage methane expansion valve and/or expander 81 , a high-stage methane flash drum 82, an intermediate-stage methane expansion valve 83 and/or expander, an intermediate-stage methane flash drum 84, a low-stage methane expansion valve 85 and/or expander, and a low-stage methane flash drum 86. While “propane,” “ethylene,” and “methane” are used to refer to respective first, second, and third refrigerants, it should be understood that these are examples only, and the presently disclosed technology may involve any combination of suitable refrigerants.

[0036] Referring to FIG. 1 , in one implementation, operation of the LNG facility 100 begins with the propane refrigeration cycle 30. Propane is compressed in a multi-stage propane compressor 31 driven by, for example, a gas turbine driver (not illustrated). The stages of compression may exist in a single unit or a plurality of separate units mechanically coupled to a single driver. Upon compression, the propane is passed through a conduit 300 to a propane cooler 32 where the propane is cooled and liquefied through indirect heat exchange with an external fluid (such as, air or water). A portion of the stream from the propane cooler 32 can then be passed through conduits 302 and 302A to a pressure reduction system 36A, for example, an expansion valve, as illustrated in FIG. 1. At the pressure reduction system 36A, the pressure of the liquefied propane is reduced, thereby evaporating or flashing a portion of the liquefied propane. A resulting two-phase stream then flows through a conduit 304A into a high-stage propane chiller 33A, which cools the natural gas stream in indirect heat exchange 38. The high stage propane chiller 33A uses the flashed propane refrigerant to cool the incoming natural gas stream in a conduit 110. Another portion of the stream from the propane cooler 32 is routed through a conduit 302B to another pressure reduction system 36B, illustrated, for example, in FIG. 1 as an expansion valve. At the pressure reduction system 36B, the pressure of the liquefied propane is reduced in a stream 304B.

[0037] The cooled natural gas stream from the high-stage propane chiller 33A flows through a conduit 114 to a separation vessel. At the separation vessel, water and in some cases a portion of the propane and/or heavier components are removed. In some cases where removal is not completed in upstream processing, a treatment system 40 may follow the separation vessel. The treatment system 40 removes moisture, mercury and mercury compounds, particulates, and other contaminants to create a treated stream. The stream exits the treatment system 40 through a conduit 116. The natural gas stream (in conduit 116) then enters the intermediate-stage propane chiller 34. At the intermediate-stage propane chiller 34, the stream is cooled in indirect heat exchange 41 via indirect heat exchange with a propane refrigerant stream. The resulting cooled stream output into a conduit 118 is routed to the low-stage propane chiller 35, where the stream can be further cooled through indirect heat exchange means 42. The resultant cooled stream exits the low-stage propane chiller 35 through a conduit 120. Subsequently, the cooled stream in the conduit 120 is routed to the high-stage ethylene chiller 53.

[0038] A vaporized propane refrigerant stream exiting the high-stage propane chillers 33A and 33B is returned to a high-stage inlet port of the propane compressor 31 through a conduit 306. An un-vaporized propane refrigerant stream exits the high-stage propane chiller 33B via a conduit 308 and is flashed via a pressure reduction system 43, illustrated, for example, in FIG. 1 as an expansion valve. The liquid propane refrigerant in the high- stage propane chiller 33A provides refrigeration duty for the natural gas stream. A two- phase refrigerant stream enters the intermediate-stage propane chiller 34 through a conduit 310, thereby providing coolant for the natural gas stream (in conduit 116) and the stream entering the intermediate-stage propane chiller 34 through a conduit 204. The vaporized portion of the propane refrigerant exits the intermediate- stage propane chiller 34 through a conduit 312 and enters an intermediate-stage inlet port of the propane compressor 31. The liquefied portion of the propane refrigerant exits the intermediatestage propane chiller 34 through a conduit 314 and is passed through a pressure-reduction system 44, for example an expansion valve, whereupon the pressure of the liquefied propane refrigerant is reduced to flash or vaporize a portion of the liquefied propane. The resulting vapor-liquid refrigerant stream is routed to the low-stage propane chiller 35 through a conduit 316. At the low-stage propane chiller 35, the refrigerant stream cools the methane-rich stream and an ethylene refrigerant stream entering the low-stage propane chiller 35 through the conduits 118 and 206, respectively. The vaporized propane refrigerant stream exits the low-stage propane chiller 35 and is routed to a low-stage inlet port of the propane compressor 31 through a conduit 318. The vaporized propane refrigerant stream is compressed and recycled at the propane compressor 31 as previously described.

[0039] In one implementation, a stream of ethylene refrigerant in a conduit 202 enters the high-stage propane chiller 33B. At the high-stage propane chiller 33B, the ethylene stream is cooled through indirect heat exchange 39. The resulting cooled ethylene stream is routed in the conduit 204 from the high-stage propane chiller 33B to the intermediate-stage propane chiller 34. Upon entering the intermediate-stage propane chiller 34, the ethylene refrigerant stream may be further cooled through indirect heat exchange 45 in the intermediate-stage propane chiller 34. The resulting cooled ethylene stream exits the intermediate-stage propane chiller 34 and is routed through a conduit 206 to enter the low- stage propane chiller 35. In the low-stage propane chiller 35, the ethylene refrigerant stream is at least partially condensed, or condensed in its entirety, through indirect heat exchange 46. The resulting stream exits the low-stage propane chiller 35 through a conduit 208 and may be routed to a separator 47. At the separator 47, a vapor portion of the stream, if present, is removed through a conduit 210, while a liquid portion of the ethylene refrigerant stream exits the separator 47 through a conduit 212. The liquid portion of the ethylene refrigerant stream exiting the separator 47 may have a representative temperature and pressure of about -24°F (about -31 °C) and about 285 psia (about 1 ,965 kPa). However, other temperatures and pressures are contemplated.

[0040] Turning now to the ethylene refrigeration cycle 50 in the LNG facility 100, in one implementation, the liquefied ethylene refrigerant stream in the conduit 212 enters an ethylene economizer 56, and the stream is further cooled by an indirect heat exchange 57 at the ethylene economizer 56. The resulting cooled liquid ethylene stream is output into a conduit 214 and routed through a pressure reduction system 58, such as an expansion valve. The pressure reduction system 58 reduces the pressure of the cooled predominantly liquid ethylene stream to flash or vaporize a portion of the stream. The cooled, two-phase stream in a conduit 215 enters the high-stage ethylene chiller 53. In the high-stage ethylene chiller 53, at least a portion of the ethylene refrigerant stream vaporizes to further cool the stream in the conduit 120 entering an indirect heat exchange 59. The vaporized and remaining liquefied ethylene refrigerant exits the high-stage ethylene chiller 53 through conduits 216 and 220, respectively. The vaporized ethylene refrigerant in the conduit 216 may re-enter the ethylene economizer 56, and the ethylene economizer 56 warms the stream through an indirect heat exchange 60 prior to entering a high-stage inlet port of the ethylene compressor 51 through a conduit 218. Ethylene is compressed in multi-stages (such as, three-stage) at the ethylene compressor 51 driven by, for example, a gas turbine driver (not illustrated). The stages of compression may exist in a single unit or a plurality of separate units mechanically coupled to a single driver.

[0041] The cooled stream in the conduit 120 exiting the low-stage propane chiller 35 is routed to the high-stage ethylene chiller 53, where it is cooled via the indirect heat exchange 59 of the high-stage ethylene chiller 53. The remaining liquefied ethylene refrigerant exiting the high-stage ethylene chiller 53 in a conduit 220 may re-enter the ethylene economizer 56 and undergo further sub-cooling by an indirect heat exchange 61 in the ethylene economizer 56. The resulting sub-cooled refrigerant stream exits the ethylene economizer 56 through a conduit 222 and passes a pressure reduction system 62, such as an expansion valve, whereupon the pressure of the refrigerant stream is reduced to vaporize or flash a portion of the refrigerant stream. The resulting, cooled two- phase stream in a conduit 224 enters the low-stage ethylene chiller/condenser 55.

[0042] A portion of the cooled natural gas stream exiting the high-stage ethylene chiller 53 is routed through conduit a 122 to enter an indirect heat exchange 63 of the low-stage ethylene chiller/condenser 55. In the low-stage ethylene chiller/condenser 55, the cooled stream is at least partially condensed and, often, subcooled through indirect heat exchange with the ethylene refrigerant entering the low-stage ethylene chiller/condenser 55 through the conduit 224. The vaporized ethylene refrigerant exits the low-stage ethylene chiller/condenser 55 through a conduit 226, which then enters the ethylene economizer 56. In the ethylene economizer 56, vaporized ethylene refrigerant stream is warmed through an indirect heat exchange 64 prior to being fed into a low-stage inlet port of the ethylene compressor 51 through a conduit 230. As shown in FIG. 1 , a stream of compressed ethylene refrigerant exits the ethylene compressor 51 through a conduit 236 and subsequently enters the ethylene cooler 52. At the ethylene cooler 52, the compressed ethylene stream is cooled through indirect heat exchange with an external fluid (such as, water or air). The resulting cooled ethylene stream may be introduced through the conduit 202 into high-stage propane chiller 33B for additional cooling, as previously described.

[0043] The condensed and, often, sub-cooled liquid natural gas stream exiting the low- stage ethylene chiller/condenser 55 in a conduit 124 can also be referred to as a “pressurized LNG-bearing stream.” This pressurized LNG-bearing stream exits the low- stage ethylene chiller/condenser 55 through the conduit 124 prior to entering a main methane economizer 73. In the main methane economizer 73, methane-rich stream in the conduit 124 may be further cooled in an indirect heat exchange 75 through indirect heat exchange with one or more methane refrigerant streams (such as, 76, 77, 78). The cooled, pressurized LNG-bearing stream exits the main methane economizer 73 through a conduit 134 and is routed to the expansion section 80 of the methane refrigeration cycle 70. In the expansion section 80, the pressurized LNG-bearing stream first passes through a high- stage methane expansion valve or expander 81 , whereupon the pressure of this stream is reduced to vaporize or flash a portion thereof. The resulting two-phase methane-rich stream in a conduit 136 enters into a high-stage methane flash drum 82. In the high-stage methane flash drum 82, the vapor and liquid portions of the reduced-pressure stream are separated. The vapor portion of the reduced-pressure stream (also called the high-stage flash gas) exits the high-stage methane flash drum 82 through a conduit 138 and enters into the main methane economizer 73. At the main methane economizer 73, at least a portion of the high-stage flash gas is heated through the indirect heat exchange means 76 of the main methane economizer 73. The resulting warmed vapor stream exits the main methane economizer 73 through the conduit 138 and is routed to a high-stage inlet port of the methane compressor 71 , as shown in FIG. 1 .

[0044] The liquid portion of the reduced-pressure stream exits the high-stage methane flash drum 82 through a conduit 142 and re-enters the main methane economizer 73. The main methane economizer 73 cools the liquid stream through indirect heat exchange 74 of the main methane economizer 73. The resulting cooled stream exits the main methane economizer 73 through a conduit 144 and is routed to a second expansion stage, illustrated as an example in FIG. 1 as intermediate-stage expansion valve 83 and/or expander. The intermediate-stage expansion valve 83 further reduces the pressure of the cooled methane stream, which reduces a temperature of the stream by vaporizing or flashing a portion of the stream. The resulting two-phase methane-rich stream output in a conduit 146 enters an intermediate-stage methane flash drum 84. Liquid and vapor portions of the stream are separated in the intermediate-stage methane flash drum 84 and output through conduits 148 and 150, respectively. The vapor portion (also called the intermediate-stage flash gas) in the conduit 150 re-enters the main methane economizer 73, wherein the vapor portion is heated through an indirect heat exchange 77 of the main methane economizer 73. The resulting warmed stream is routed through a conduit 154 to the intermediate-stage inlet port of methane compressor 71 .

[0045] The liquid stream exiting the intermediate-stage methane flash drum 84 through the conduit 148 passes through a low-stage expansion valve 85 and/or expander, whereupon the pressure of the liquefied methane-rich stream is further reduced to vaporize or flash a portion of the stream. The resulting cooled two-phase stream is output in a conduit 156 and enters a low-stage methane flash drum 86, which separates the vapor and liquid phases. The liquid stream exiting the low-stage methane flash drum 86 through a conduit 158 comprises the liquefied natural gas (LNG) product at near atmospheric pressure. This LNG product may be routed downstream for subsequent storage, transportation, and/or use.

[0046] A vapor stream exiting the low-stage methane flash drum 86 (also called the low- stage methane flash gas) in a conduit 160 is routed to the main methane economizer 73. The main methane economizer 73 warms the low-stage methane flash gas through an indirect heat exchange 78 of the main methane economizer 73. The resulting stream exits the main methane economizer 73 through a conduit 164. The stream is then routed to a low-stage inlet port of the methane compressor 71.

[0047] The methane compressor 71 comprises one or more compression stages. In one implementation, the methane compressor 71 comprises three compression stages in a single module. In another implementation, one or more of the compression modules are separate but mechanically coupled to a common driver. Generally, one or more intercoolers (not shown) are provided between subsequent compression stages. [0048] As shown in FIG. 1 , a compressed methane refrigerant stream exiting the methane compressor 71 is discharged into a conduit 166. The compressed methane refrigerant is routed to the methane cooler 72, and the stream is cooled through indirect heat exchange with an external fluid (such as, air or water) in the methane cooler 72. The resulting cooled methane refrigerant stream exits the methane cooler 72 through a conduit 112 and is directed to and further cooled in the propane refrigeration cycle 30. Upon cooling in the propane refrigeration cycle 30 through a heat exchanger 37, the methane refrigerant stream is discharged into a conduit 130 and subsequently routed to the main methane economizer 73, and the stream is further cooled through indirect heat exchange 79. The resulting sub-cooled stream exits the main methane economizer 73 through a conduit 168 and then combined with the stream in the conduit 122 exiting the high-stage ethylene chiller 53 prior to entering the low-stage ethylene chiller/condenser 55, as previously discussed.

[0049] In some cases, excessive amounts of nitrogen are removed from the liquefied natural gas stream through the use of one or more nitrogen rejection units used in conjunction with a cascade LNG system as described above. Nitrogen is most efficiently removed from natural gas at cryogenic temperatures. As such, the nitrogen rejection unit as described herein can be integrated into one or more insulated elements of the above LNG system. In one implementation a plurality of streams can be run through the nitrogen rejection unit simultaneously.

[0050] FIG. 2 illustrates a core-in-shell heat exchanger having one or more cores implemented therein. A core-in-shell heat exchanger 400 can be operably implemented in an LNG cascade process as described above with respect to FIG. 1 , including, but not limited to, a propane refrigeration cycle, an ethylene refrigeration cycle, a methane refrigeration cycle, and/or a nitrogen rejection unit. The core-in-shell heat exchanger 400 can be implemented with gases, liquids, liquid/vapor mixtures, and/or combinations thereof for heat transfer, evaporation, and/or condensation.

[0051] The core-in-shell heat exchanger 400 can include a shell 402 and one or more heat exchanger cores 404 disposed therein. The one or more cores 404 can be Formed Plate Heat Exchanger (FPHE) cores. The core-in-shell heat exchanger 400 can include the shell 402 formed of carbon steel, stainless steel, and/or the similar metallurgies and the one or more cores 404 similarly formed of a carbon steel, stainless steel, and/or similar metallurgies. The one or more cores formed of a carbon steel, stainless steel, and/or similar metallurgies can provide increased operational temperatures, increased operational temperature fluctuations, increased operational pressures, mercury resistance, and/or increased stream differential temperatures.

[0052] The shell 402 can have an interior space 403 operable to receive a cooling fluid 406 therein via one or more conduits 408. The shell 402, via the one or more conduits 408, can maintain the cooling fluid 406 at or above a predetermined level 407 and contact at least a portion of the one or more cores 404. In at least one instance, the predetermined level 407 of the cooling fluid 406 can be at or below a top of the one or more cores 404.

[0053] The cooling fluid 406 can draw indirect heat exchange with the one or more cores 404, which can cause evaporation of at least a portion the cooling fluid 406. The cooling fluid 406 can evaporate and/or boil out of the shell 402 via one or more cooling fluid outlets 409. In some instances, the cooling fluid 406 can be operable to move (e.g. flow) side-to- side and/or top-to-bottom depending on the design of the shell 402 and/or one or more cores 404. The one or more cores 404 disposed within the cooling fluid 406 can operable to induce a thermosyphon effect, thereby pulling the cooling fluid 406 into the one or more cores 404 where heat transfer occurs causing the cooling fluid 406 to boil out the top of the one or more core 404.

[0054] In some instances, the cooling fluid 406 can be condensed within the shell 402, via a condenser, a compressor, and/or other element operable cool the vapor into a cooling fluid 406 again. The condensed fluid can be returned to the shell 402 and/or a reservoir fluidically coupled with the shell 402. In at least one instance, at least one of the one or more conduits 408 can be fluidly coupled with a reservoir operable to maintain the cooling fluid 406 at the predetermined level 407.

[0055] Each of the one or more cores 404 can be operable to receive a feed fluid 410 through an inlet 412 into a feed portion of the one or more cores 404. The feed fluid 410 can transfer heat to the cooling fluid 406 as the feed fluid 410 flows through the feed portion of the core 404. The feed fluid 410 can enter the one or more cores 404 through the inlet 412 formed in the shell 402. After rejection of heat by the feed fluid 410 as it passes through the feed portion of the core 404, the feed fluid 410 can exit the one or more cores 404 at the outlet 414. In at least one instance, the feed fluid 410 can be a gas feed stream and the outlet 414 can produce a liquid gas feed stream.

[0056] The feed fluid 410 can enter the shell 402, via the one or more inlets 412, and subsequently the one or more cores 404 from the top and/or side of the shell 402. A feed fluid 410 entering the shell 402 from the side can enter directly into the one or more cores 404 and begin a heat transfer process. A feed fluid 410 entering the shell 402 from the top (as detailed in FIG. 2) can have a vertical feed fluid 410 flow, which can be changed to a horizontal feed fluid 410 flow prior to beginning the heat transfer process. The feed fluid 410 can exit the one or more cores via the outlet 414 which can be formed on a side surface of the shell 402, thereby maintaining the horizontal flow of the feed fluid. In other instances, the outlet 414 can be formed on a bottom surface of the shell 402.

[0057] Each of the one or more cores 404 can be fluidically isolated one from the other and can have separate inlets 412 of a feed fluid 410 as illustrated in FIG. 2. Each of the one or more cores 404 can be operable receive the same feed fluid 410 (e.g. a natural gas feed stream) or each of the one or more cores 404 can be operable to receive a unique feed fluid 410, and/or combinations thereof. In at least one instance, the shell 402 can have a plurality of cores 404 including a feed gas core, an ethylene core, a methane recycle core, and/or a heavies removal core. In other instances, the one or more cores 404 can be bed via a single inlet 412 that distributes the feed fluid 410 to the one or more cores via a header, thus fluidically coupling one or more cores 404 together. While FIG. 2 illustrates three cores 404, it is within the scope of the present disclosure to implement any number of cores 404 arranged serially and/or in parallel including, but not limited to, two cores, three cores, four cores, and/or any other number of cores 404 within shell 402. The shell 402 can be designed and/or arranged to have an interior space 403 operable to receive the desired number of cores 404. [0058] In other instances, the one or more cores 404 can be arranged serially within a shell 402 having a single inlet 412. A first core 404 can feed directly into a second core, while the second and subsequent cores can feed serially to the next core 404 within a shell 402. The shell 402 can implement any number of cores 404 arranged in series including, but not limited to, two cores, three cores, four cores, and/or five or more cores 404.

[0059] A head pressure within the cooling fluid 406 can induce the cooling fluid 406 through a cooling portion of the core 404, thereby maximizing heat transfer between the feed fluid 410 and/or the cooling fluid 406. The cooling fluid 406 can be a two-phase fluid within the one or more cores 404 as the cooling fluid 406 receives heat transfer from the feed fluid 410. A vapor phase of the cooling fluid 406 can exit the via the one or more cooling fluid outlets 409 while a liquid phase of the cooling fluid 406 can fall back down into the cooling fluid at the predetermined level 407. The feed fluid 410 can be disposed in a portion of the core 404 fluidically sealed and independent from the second portion of the 404 exposed to the cooling fluid 406, thereby allowing indirect heat exchange.

[0060] The one or more cores 404 can be coupled with the core-in-shell heat exchanger 400 via the inlet 412. The one or more cores 404 can be formed of stainless steel, Invar, and/or similar metallurgies, thereby eliminating a transition joint between the core 404, the inlet 412, and/or the shell 402. The elimination of a transition joint between the one or more cores 404 and/or the shell 402 can reduce the potentials for leaks. For example, the elimination of one or more transition joints in the LNG System 100 of FIG. 1 may reduce leak potential due to transition joint leaks. The need for a transition joint can be eliminated by implementing a core metallurgy of stainless steel, Invar (e.g. a nickel-iron-alloy), and/or similar.

[0061] The use of stainless steel, Invar, and/or similar can also reduce thermal shock and/or thermal stress on the core-in-shell heat exchanger 400 compared with an aluminum core, thus further reducing the risk of leaks. The stainless steel, Invar, or similar core within the core-in-shell heat exchanger 400 can additionally allow for a faster warm-up and/or cool down time, enhancing process availability. The core can also minimize the need for alarms and/or controls relating to temperature excursions. [0062] FIG. 3 illustrates a diagrammatic view of an FPHE for use in a core-in-shell heat exchanger. An FPHE core 500 can be implemented within a core-in-shell heat exchanger (as shown with respect to FIG. 2) and can be operable to transfer heat between two fluids. The FPHE core 500 can implement a plate-fin style heat exchanger similar to brazed aluminum heat exchangers (BAHX) but constructed of stainless steel, Invar, and/or other metallurgies, thereby eliminating the need for a transition joint between the FPHE core 500, an inlet and/or the shell (shown in FIG. 2).

[0063] The FPHE core 500 can be formed of a plurality of layers 502 including a plurality of A layers 504 and a plurality of B layers 506. The plurality of A layers 504 and the plurality of B layers 506 can correspond to at least one of the two fluid flows (e.g. a feed fluid flow and a cooling fluid flow), respectively. In at least one instance, the plurality of A layers 504 can correspond to a hot fluid (e.g. feed fluid) while the plurality of B layers 506 can correspond to a cold fluid (e.g. cooling fluid), wherein the FPHE core 500 is operably arranged to transfer heat from the hot fluid within the plurality of A layers 504 to the cold fluid within the plurality of B layers 506, via indirect heat exchange.

[0064] Each of the plurality of layers 502 can be formed by two side bars 508 and a plurality of fins 510, and parting sheets 512, thereby defining an active heat transfer area 514 of an individual layer. The parting sheets 512 define the parallel fluid flow path(s) through the heat transfer area 514 within an individual layer of the plurality of layers 502. The parting sheets 512 can define an upper surface and/or a lower surface of the active heat transfer area 514 to allow heat transfer between adjacent layers of the plurality of layers 502 while providing a barrier therebetween to prevent mixing and/or contact between the two fluids. The FPHE core 500 can include one or more end plates 520 disposed on either side of the first and/or last of the plurality of layers 502. The one or more end plates 520 can form an upper surface of the active area of the first layer of the plurality of layers 502, and a lower surface of the active area of the last layer of the plurality of layers 502.

[0065] The FPHE core 500 can be formed by stacking an arrangement one of the plurality of A layers 504 followed by one of the plurality of B layers 506 and repeating for a predetermined number of layers 502. The predetermined number of the plurality of layers 502 can be determined based on the desired pressure drop desired across the FPHE core 500, the heat transfer duty required, the size of the layers, and/or the desired size of the FPHE core 500. The FPHE core 500 including the plurality of layers 502 can then be diffusion bonded to form a metallurgic bonded core. The diffusion bonding process can include heat, pressure, and a controlled atmosphere to bring the plurality of layers 502 and/or the end plates 520 into intimate contact and promote grain growth and atom movement therebetween.

[0066] The plurality of fins 510 can have a fin leg 516 and a fin crown 518 arranged to maximize the heat transfer of the fluid within an individual layer of the plurality of layers 502. The arrangement of the plurality of fins 510, including the fin leg 516 and/or the fin crown 518 can be adjusted based on the application and/or implementation of the FPHE core 500. In at least one instance, a lower pressure drop across an individual layer of the plurality of layers 502 can be achieved by minimizing the number of fins 510, and by optimizing fin leg 516 and/or fin crown 518 dimensions, thereby providing a more open fluid flow path within the individual layer of the plurality of layers 502.

[0067] FIG. 4A illustrates a two-stream FPHE including of multiple layers of parallel process streams. FIG. 4B illustrates a two-stream FPHE including multiple layers of parallel refrigerant streams. FIG. 4C illustrates a partially exploded view of a two-stream FPHE including multiple layers of parallel process streams and multiple layers of parallel refrigerant streams. An FPHE 600 may be deployed in one or more processes, such as the cascade LNG facility 100 of FIG. 1. The FPHE 600 can be a two-stream heat exchanger. The FPHE 600 can optionally include one or more process stream distributors 603 (shown in FIG. 4C) within the FPHE 600 feed passes 601 to change the entering flow direction from vertical to horizontal within the feed pass inlet of the FPHE 600 and/or if desired to change the exiting flow direction from horizontal to vertical within the feed pass outlet of the FPHE 600. One, two, or a plurality of FPHE exchanger cores 600 with the same feed stream and/or separate process streams 601 can be included within the same process vessel to share a common refrigerant for all the cooling layers 602. [0068] FIG. 5A demonstrates two possible flow patterns for layers in a core. In one pattern an exchange fluid flows from top to bottom, while an adjacent fluid flows in from one side, up, and out the other side. In at least one instance, the exchange fluid can be a cooling fluid and the adjacent fluid flow can be a feed fluid. A more complex pattern can have fluid traversing side to side as shown in FIG. 5B. As with FIG. 5A, an exchange fluid can flow top to bottom while traversing side to side and an adjacent fluid flows in from one side and out an opposing side while traversing side to side. In at least one instance, the exchange fluid can be a cooling fluid and the adjacent fluid flow can be a feed fluid. While FIGS. 5A and 5B illustrate fluid flow patterns for an exchange fluid and an adjacent fluid flow, it is within the scope of the present disclosure to implement any number of fluid flow patterns, directions, shapes, arrangements, including but not limited to direct flow patterns and/or convoluted flow patterns depending on the feed fluid, cooling fluid, heat transfer duty, pressure drop, and/or size and shape of the one or more cores. There are a large number of alternative configurations that may also be used.

[0069] The fluid flow paths illustrated in FIGS. 5A and/or 5B associated with the exchange fluid flows and/or the adjacent fluid flows can be plates etched with the desired flow patterns and assembled as described with respect to FIG. 3. The plates can be etched and then stacked in alternating layers (e.g exchange fluid flow plate, adjacent fluid flow plate, exchange fluid flow plate, adjacent fluid flow plate, etc.) for a predetermined number of layers depending on the size of the desired core. Printed Circuit Heat Exchangers (PCHE) and FPHE described herein may utilize one of the flow patterns illustrated in FIGS. 5A-5B.

[0070] The systems described herein may manifold multiple FPHE cores together in parallel within a single shell. This generally occurs when heat transfer surface area requirements exceed the single core size that can physically accommodate inside a diffusion bonding vacuum furnace. Core-in-shell heat exchangers provide the flow of the refrigerant/bath through the core and out the top. By having the fluid level just below the top of the core, the warmed fluid is lighter than the bath and flows out of the core. In other words, in a core-in-shell application, the refrigerant is kept at a level below the top of the core. The refrigerant is directed up through the exchanger cooling passes, boiling out the top. Alternatively, the cooled fluid or gas may go side to side or top to bottom in some instances. In one implementation, the cooled gas is directed in from one side, turns down, and is directed out the bottom. The bath of refrigerant acts as a thermosyphon pulling refrigerant from the bottom into the core, where it heats and boils out the top. The cooled fluid or gas is then chilled both by the liquid refrigerant and the phase change from liquid to gas. However, in some instances, different heat exchange may have different size limitations for the core-in-shell heat exchangers. As such, the amount of material used and footprint of the heat exchanger is reduced in the presently disclosed technology. The cores are constructed considering cost, shell size, and number of cores as a function of the amount of material being processed, including volume and rate.

[0071] The process may enter the vessel and then the core from the top or side. If it enters through the vessel head, it is directed straight into the process passes. If it enters from the top, the vertical direction is changed to flow horizontally. In some instances, the direction can be changed and exit the bottom of the vessel. Generally, it exits either the side of the vessel or the end of the vessel through the head.

[0072] In one example, during manufacturing, the plates are etched with a desired pattern (e.g., a relatively straight pathway for refrigerant, an angled or contoured pathway for warm stream, etc.). The plates and core are assembled, and the assembled heat exchanger is bonded in a brace furnace. During operation, the refrigerant bubbles up through in the vertical direction. The vapor exits the vessel through the vessel refrigerant outlet nozzles (e.g., the cooling fluid outlets). The liquid falls back down into the liquid level. A two- phase mix is continuously circulating through the cooling passes, liquid at the bottom, and two-phase throughout as the process heat boils the refrigerant. The refrigerant vapor outlet nozzles (vapor from inlet flash and from vaporized liquid due to process heat) may be disposed along the top to allow all refrigerant vapor to exit the vessel. There are many benefits of the presently disclosed technology, as will be appreciated by those skilled in the art, including but not limited to, increased temperature, increased pressure, mercury resistance, increased operational temperature fluctuation, increased startup temperature differential, increased stream differential temperature, and/or the like. [0073] While examples of the present technology have been shown and described herein, it will be obvious to those skilled in the art that such examples are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the disclosure. It should be understood that various alternatives to the examples of the disclosure described herein can be employed in practicing the disclosure. It is intended that the following claims define the scope of the disclosure and that methods and structures within the scope of these claims and their equivalents be covered thereby.

Claims (16)

CLAIMS What is claimed is:

1 . A core-in-shell heat exchanger comprising: a shell having an interior portion operable to receive a cooling fluid therein; and a formed plate heat exchanger (FPHE) core operably arranged within the interior portion, the FPHE core including: an inlet coupled with a feed stream, a plurality of feed layers fluidly coupled with the inlet, and a plurality of cooling layers fluidly coupled with the interior portion and operable to receive at least a portion of the cooling fluid therein.

2. The core-in-shell heat exchanger of claim 1 , wherein, the shell is formed from an aluminum, titanium, stainless steel, an iron based alloy, and/or a nickel alloy steel, the FPHE core is formed of titanium, copper, stainless steel, an iron based alloy, and/or a nickel alloy steel, and the FPHE core is coupled directly with the shell.

3. The core-in-shell heat exchanger of claim 2, wherein at least one of the shell or the FPHE core is formed of Invar and/or any other iron and nickel alloy.

3. The core-in-shell heat exchanger of claims 1 or 2, wherein the plurality of feed layers and the plurality of cooling layers are diffusion bonded.

4. The core-in-shell heat exchanger of any one of claims 1-3, wherein each of the plurality of feed layers includes a plurality of fins and optionally fin types forming a feed

24 stream flow path or feed stream paths therethrough, and each of the plurality of cooling layers includes a plurality of fins and optionally fin types forming a cooling flow path or cooling paths therethrough.

5. The core-in-shell heat exchanger of any one of claims 1-4, wherein the FPHE core includes one or more vapor/liquid separators upstream of the feed pass inlet to the FPHE to facilitate two-phase flow distribution to the feed passes of the FPHE.

6. The core-in-shell heat exchanger of claim 5, wherein the FPHE includes multiple parallel feed gas layers exchanging heat with multiple parallel cooling layers.

7. The core-in-shell heat exchanger of any one of claims 1-6, further comprising: a second FPHE core operably arranged within the interior shell portion, wherein the second FPHE core comprises: a second inlet coupled with a feed stream, a plurality of second feed layers fluidly coupled with the second inlet, and a plurality of second cooling layers fluidly coupled with the interior shell portion and operable to receive at least a portion of the cooling fluid therein, and wherein the FPHE core and the second FPHE core share a common cooling fluid but are fluidically isolated.

8. The core-in-shell heat exchanger of any one of claims 1 -7, wherein the cooling fluid is propane, propylene, ethylene, ethane, methane, and/or any other hydrocarbon or mixture thereof, and any other commercially available refrigerant.

9. A liquefied natural gas (LNG) system comprising: a gas feed stream; and a core-in-shell heat exchanger having an inlet coupled with the gas feed stream, the core-in-shell heat exchanger including: a shell having an interior portion operable to receive a cooling fluid therein, and a formed plate heat exchanger (FPHE) core operably arranged within the interior shell portion and disposed within at least a first portion of the cooling fluid, the FPHE core having a plurality of feed layers fluidly coupled with the inlet and operable to receive the feed stream therein and a plurality of cooling layers operable to receive at least a second portion of the cooling fluid therein, wherein the plurality of feed layers exchange heat with a plurality of separate cooling layers.

10. The LNG system of claim 9, further comprising: a second core-in-shell heat exchanger having a second inlet coupled with the outlet of the FPHE core of the core-in-shell heat exchanger, the second core-in-shell heat exchanger including: a second shell having a second interior shell portion operable to receive a second cooling fluid therein, and a second FPHE core operably arranged within the second interior shell portion and disposed within at least a first portion of the second cooling fluid, the second FPHE core having a plurality of second feed layers fluidly coupled with the second inlet and operable to receive an outlet stream of the first core-in-shell heat exchanger and a plurality of second cooling layers operable to receive at least a second portion of the second cooling fluid therein, wherein the plurality of second feed layers exchange heat with a plurality of separate cooling layers.

11 . The LNG system of claims 9 or 10, further comprising: a third, fourth, fifth, or plurality of core-in-shell heat exchanger(s) having an inlet(s) coupled with the second outlet of the second FPHE core of the second core-in-shell heat exchanger, the third, fourth, fifth, or plurality of core-in-shell heat exchanger(s) including: a third, fourth, fifth, or a plurality of shells having an interior shell portion operable to receive a third, fourth, fifth, or a plurality of cooling fluid(s) therein, and a third, fourth, fifth, or a plurality of FPHE core(s) operably arranged within the third, fourth, fifth, or plurality of interior shell portion(s) and disposed within at least a first portion of the third cooling fluid, the third, fourth, fifth, or plurality of FPHE core(s) having a plurality of feed layers fluidly coupled with the third, fourth, fifth or plurality of inlet(s) and operable to receive an outlet stream of the second, third, fourth, fifth or plurality of core-in-shell heat exchanger and a plurality of cooling layers operable to receive at least a second portion of the third, fourth, fifth or plurality of cooling fluid(s) therein, wherein the plurality of feed layers exchange heat with a plurality of separate cooling layers.

12. The LNG system of claims 9 or 10, further comprising: a third, fourth, fifth, or plurality of core-in-shell heat exchanger(s) having one or more inlets coupled with the second outlet of the second FPHE core of the second core- in-shell heat exchanger, wherein the third, fourth, fifth, or plurality of core-in-shell heat exchangers include: an interior shell portion operable to receive a cooling fluid therein, and one or more FPHE cores operably arranged within interior shell portion and disposed within at least a first portion a cooling fluid therein; a plurality of feed layers fluidly coupled with the one or more inlets and

27 operable to receive an outlet stream of one or more of the the second, third, fourth, fifth, and/or plurality of core-in-shell heat exchangers and a plurality of cooling layers operable to receive at least a second portion the cooling fluid, wherein the plurality of feed layers exchange heat with the plurality of cooling layers

13. The LNG system of any one of claims 9-12, wherein the outlet of one of the core-in-shell heat exchangers, the second core-in-shell heat exchanger, and/or the third, fourth, fifth, or plurality of core-in-shell heat exchanger(s) produces a liquefied gas stream.

14. The LNG system of claims 11-13, wherein the cooling fluid, the second cooling fluid, and/or the third cooling fluid are at least one of propane, propylene, ethylene, ethane, methane, and/or any other hydrocarbon or mixture thereof, and any other commercially available refrigerant.

15. The LNG system of any one of claims 9-14, wherein the shell is formed of aluminum, titanium, stainless steel, an iron based alloy, or a nickel alloy steel, the FPHE core is formed of titanium, copper, stainless steel, an iron based alloy, or a nickel alloy steel, and the FPHE core is coupled directly with the shell; and wherein the FPHE core(s) is coupled directly within the shell(s).

16. The LNG system of any one of claims 9-15, wherein the FPHE core(s) include(s) one or more vapor/liquid separators upstream of the feed pass inlet to the FPHE to facilitate two-phase flow distribution to the feed passes of the FPHE.

28