AU2013202033A1

AU2013202033A1 - Modular lng production facility

Info

Publication number: AU2013202033A1
Application number: AU2013202033A
Authority: AU
Inventors: Geoffry Brian Byfield
Original assignee: Woodside Energy Technologies Pty Ltd
Current assignee: Woodside Energy Technologies Pty Ltd
Priority date: 2013-03-27
Filing date: 2013-03-27
Publication date: 2014-10-16

Abstract

- 43 A liquefied natural gas production process for producing a product stream of liquefied natural gas at a production location is disclosed. The process comprises: a) designing a 5 plurality of modules for installation at the production location to form a production train; b) arranging the plurality of modules at the production location to form the production train, the plurality of modules including at least; a first module assigned to perform a first selected function, a second module assigned to perform a second selected function, and a third module assigned to perform a third selected function; c) positioning the first module 10 base parallel to and axially offset in a first direction relative to the central longitudinal axis of the production train; d) positioning the second module base adjacent to the first module base such that the second module is parallel to and axially offset in a second opposing direction relative to the central longitudinal axis of the production train; e) positioning the third module base parallel to and in co-alignment with the central 15 longitudinal axis of the production train wherein the third module is in direct fluid communication with the first module and the second module; and, f) processing a selected feed rate of natural gas in the production train to produce the product stream of liquefied natural gas.

Description

- 1 MODULAR LNG PRODUCTION FACILITY FIELD OF THE INVENTION The present invention relates to a liquefied natural gas production process for producing a 5 product stream of liquefied natural gas at a production location using a plurality of modules. BACKGROUND TO THE INVENTION Natural gas ("NG") is routinely transported from one location to another location in its 10 liquid state as "Liquefied Natural Gas" (LNG). Liquefaction of the natural gas makes it more economical to transport as LNG occupies only about 1/600th of the volume that the same amount of natural gas does in its gaseous state. After liquefaction, LNG is typically stored in cryogenic containers either at or slightly above atmospheric pressure. LNG is regasified before distribution to end users through a pipeline or other distribution network 15 at a temperature and pressure that meets the delivery requirements of the end users. Wellhead gas is subjected to gas pre-treatment to remove contaminants prior to liquefaction. The hydrogen sulphide and carbon dioxide can be removed using a suitable process such as amine adsorption. Removal of water can be achieved using conventional 20 methods, for example, a molecular sieve. Depending on the composition of contaminants present in the inlet gas stream, the inlet gas stream may be subjected to further pre treatment to remove other contaminants, such as mercury and heavy hydrocarbons prior to liquefaction. Liquefaction is achieved using methods that are well established in the art which typically involve compression and cooling. Such processes include the APCI 25 C3/MRTM or Split MRTM or AP-XTM, processes, the Phillips Optimized Cascade Process, the Linde Mixed Fluid Cascade process or the Shell Double mixed Refrigerant or Parallel Mixed Refrigerant process. Regardless of the choice of liquefaction process, refrigerants are used to reduce the temperature of the treated wellhead gas to a temperature of around 160'C to form LNG, resulting in warming of the refrigerant which must be compressed 30 for recycle to the liquefaction process. The compressors used for this duty are traditionally gas turbines or electric motors depending on the power requirements and layout issues of a particular LNG production facility. The coolers required for the various compression -2 and heat exchanger operations associated with an LNG plant may be air coolers or water coolers arranged in a heat exchanger bank. Prior art modularised LNG production trains have been closely based upon the design and 5 layout of the more traditional stick-built LNG production trains. Until now, modularisation has been conducted by slicing up an existing stick built LNG train design into transportable sections, leading to some compromises regarding the placement of the module boundaries. Prior art examples of modularization of a traditional stick-built air cooled LNG train have relied on dividing the air-cooled heat exchanger bank into the 10 smallest number of modules possible for a given size of air cooler within the air-cooled heat exchanger bank. One example of a prior art modular LNG production facility is illustrated schematically in FIG.1. The facility includes Prior Art Module A (1), Prior Art Module B (2), Prior Art Module C (3), Prior Art Module D (4), and, Prior Art Module E (5). To keep the overall plot size of the LNG production facility to a minimum, it is 15 known to arrange sub-sections of the air-cooled heat exchanger bank (6) over the top of each module so as to cover one hundred percent of the area defined by the base of said module with a view to making the air-cooled heat exchanger bank as large as possible for a given module size. The heat exchanger bank (6) is made up of a first row of heat exchanger bays (7) and a second row of heat exchanger bays (8). The first and second 20 rows of heat exchanger bays extend parallel to each other along the full length of the production facility. Each of Prior Art Module A (1), Prior Art Module B (2), Prior Art Module C (3), Prior Art Module D (4), and, Prior Art Module E (5) include a portion of the first row of heat exchanger bays (7) and a section of the second row of heat exchanger bays (8). In addition to this, common services (9) which run along the length of the prior 25 art facility of FIG. 1, are required to cross each and all of Prior Art Module A (1), Prior Art Module B (2), Prior Art Module C (3), Prior Art Module D (4), and, Prior Art Module E (5). The prior art arrangement of FIG. 1 has several disadvantages. A high number of 30 interconnections are required between the modules and the heat exchanger bank. The use of a large number of small modules inevitably requires that the plurality of individual air coolers within the air-cooled heat exchanger bank that are required to perform the cooling -3 duty for the selected function of a particular module will need to span across at least two modules, preventing fluid circulation through the air coolers until these two modules are joined at the production location. These prior art designs rely on duplication of structural steel as there is inevitably a large amount of void space underneath the air-cooled heat 5 exchanger bank in addition to the structural steel that is used for the uncovered spatially offset process equipment modules. There remains a need to explore alternative designs for a modular LNG production plant to alleviate at least one of these problems. 10 SUMMARY OF THE INVENTION According to a first aspect of the present invention there is provided a liquefied natural gas production process for producing a product stream of liquefied natural gas at a production location, said process comprising: 15 a) designing a plurality of modules for installation at the production location to form a production train, each module having a module base for mounting a plurality of plant equipment associated with a selected function associated with the production of liquefied natural gas, said selected function being assigned to said module; b) arranging the plurality of modules at the production location to form the 20 production train, the production train having a central longitudinal axis, the plurality of modules including at least; a first module assigned to perform a first selected function, a second module assigned to perform a second selected function, and a third module assigned to perform a third selected function; c) positioning the first module base parallel to and axially offset in a first direction 25 relative to the central longitudinal axis of the production train; d) positioning the second module base adjacent to the first module base such that the second module is parallel to and axially offset in a second opposing direction relative to the central longitudinal axis of the production train; and, e) positioning the third module base parallel to and in co-alignment with the central 30 longitudinal axis of the production train wherein the third module is in direct fluid communication with the first module and the second module; and, f) processing a selected feed rate of natural gas in the production train to produce the -4 product stream of liquefied natural gas. In one form, the process further comprises the step of designing a heat exchanger bank having a central longitudinal axis parallel to the central longitudinal axis of the production 5 train, the heat exchanger bank including: a first row of heat exchanger bays parallel to and axially offset in a first direction relative to the central longitudinal axis of the heat exchanger bank; and, an adjacent second row of heat exchanger bays parallel to and axially offset in a second direction relative to the central longitudinal axis of the heat exchanger bank, wherein the first module includes a first sub-section of the first row of 10 heat exchanger bays without including a sub-section of the second row of heat exchanger bays. In one form, the process further comprises the steps of arranging a first plurality of heat exchangers operatively associated with the first selected function on the first module base 15 to form a first sub-section of the first row of heat exchanger bays, the first plurality of heat exchangers being arranged on an elevated level vertically offset from the first module base to provide a covered section of the first module base. In one form, the process further comprises the step of sizing the first module base to 20 include a covered section for mounting of the first plurality of heat exchangers and an uncovered section for mounting a selected piece of process equipment. In one form, the selected piece of equipment is; a rotating piece of equipment associated with a circulating refrigerant, a piece of equipment having a flammable inventory, a long lead-time piece of equipment, or, a piece of equipment having an overall height that is taller than the height 25 of the elevated level. In one form, the process further comprises the steps of arranging a second plurality of heat exchangers operatively associated with the second selected function on the second module base to form a first sub-section of the second row of heat exchanger bays, the second 30 plurality of heat exchangers being arranged on an elevated level vertically offset from the second module base to provide a covered section of the second module base.

-5 In one form, the process further comprises the step of sizing the second module base to include a covered section for mounting of the second plurality of heat exchangers and an uncovered section for mounting a selected piece of process equipment. In one form, the selected piece of equipment is; a rotating piece of equipment associated with a circulating 5 refrigerant, a piece of equipment having a flammable inventory, a long lead-time piece of equipment, or, a piece of equipment having an overall height that is taller than the height of the elevated level. In one form, the process further comprises the steps of arranging a third plurality of heat 10 exchangers operatively associated with the third selected function on the third module base to form a portion of the first row of heat exchanger bays and a portion of the second row of heat exchanger bays, the third plurality of heat exchangers being arranged on an elevated level vertically offset from the third module base to provide a covered section of the third module base. 15 In one form, the process further comprises the steps of sizing the third module base such that the third plurality of heat exchangers covers at least 90% of the third module base to form a fully covered third module. 20 In one form, the process further comprises the step of constructing at least one of the plurality of modules at a construction location or assembling at least one of the plurality of modules at an assembly location prior to transport to the production location, and testing the at least one module for verification purposes at the construction or assembly location. 25 In one form, the first module is one of a plurality of first modules. In one form, the second module is one of a plurality of second modules. In one form, one of the plurality of modules is a pre-treatment module for removing 3 0 contaminants from a natural gas feed stream to produce a pre-treated natural gas stream.

-6 In one form, one of the plurality of modules is a first refrigerant condenser module for pre-cooling a pre-treated natural gas stream to produce a pre-cooled gas stream and a first refrigerant vapour stream. 5 In one form, one of the plurality of modules is a first refrigerant compression module for compressing a first refrigerant vapour stream to produce a compressed first refrigerant stream for recycle to a first refrigerant condenser module. In one form, one of the plurality of modules is a liquefaction module operatively 10 associated with a main cryogenic heat exchanger for further cooling a pre-cooled gas stream through indirect heat exchange with a second refrigerant to produce a liquefied natural gas product stream and a second refrigerant vapour stream. In one form, one of the plurality of modules is a second refrigerant compression module 15 for compressing a second refrigerant vapour stream to produce a compressed second refrigerant stream for recycle to a main cryogenic heat exchanger. In one form, the second refrigerant compression module is a partially covered module having a first uncovered section of the base on a first side of the heat exchanger bank and 20 a second uncovered section of the module on a second side of the heat exchanger bank after installation at the production location and wherein a first refrigerant compressor is arranged on the first uncovered section and a second refrigerant compressor is arranged on the second uncovered section. 25 In one form, the first refrigerant is propane or nitrogen. In one form, the second refrigerant is a mixed refrigerant hydrocarbon mixture or nitrogen. In one form, each of the plurality of modules is substantially equally sized. 3 0 In one form, the production location is onshore, offshore on a floating facility, offshore on a fixed facility, barge-mounted or grounded facility.

-7 In one form, the heat exchangers are air-cooled heat exchangers. According to a second aspect of the present invention there is provided a liquefied natural gas production process for producing a product stream of liquefied natural gas at a 5 production location, said process comprising: designing or constructing a plurality of spaced-apart modules for installation at a production location to form a production train, the production train having a central longitudinal axis, each module having a module base for mounting a plurality of plant equipment associated with a selected function assigned to said module; and, 10 designing or constructing a heat exchanger bank having a central longitudinal axis parallel to the central longitudinal axis of the production train, the heat exchanger bank including a plurality of heat exchanger bays including at least a first row of heat exchanger bays and a second row of heat exchanger bays, the first and second rows of heat exchanger bays arranged to run parallel to central longitudinal axis of the heat 15 exchanger bank, wherein the plurality of modules includes a first module and said first module is arranged within the production train to include a first sub-section of the first row of heat exchanger bays without including a sub-section of the second row of heat exchanger bays. 20 In one form, the process further comprises the steps of arranging a first plurality of heat exchangers operatively associated with the first selected function on the first module base to form a first sub-section of the first row of heat exchanger bays, the first plurality of heat exchangers being arranged on an elevated level vertically offset from the first module base to provide a covered section of the first module base. 25 In one form, the process further comprises the step of sizing the first module base to include a covered section for mounting of the first plurality of heat exchangers and an uncovered section for mounting a selected piece of process equipment. In one form, the selected piece of equipment is; a rotating piece of equipment associated with a circulating 30 refrigerant, a piece of equipment having a flammable inventory, a long lead-time piece of equipment, or, a piece of equipment having an overall height that is taller than the height of the elevated level.

-8 In one form, the process further comprises the steps of arranging a second plurality of heat exchangers operatively associated with the second selected function on the second module base to form a first sub-section of the second row of heat exchanger bays, the second plurality of heat exchangers being arranged on an elevated level vertically offset from the 5 second module base to provide a covered section of the second module base. In one form, the process further comprises the step of sizing the second module base to include a covered section for mounting of the second plurality of heat exchangers and an uncovered section for mounting a selected piece of process equipment. In one form, the 10 selected piece of equipment is; a rotating piece of equipment associated with a circulating refrigerant, a piece of equipment having a flammable inventory, a long lead-time piece of equipment, or, a piece of equipment having an overall height that is taller than the height of the elevated level. 15 In one form, the process further comprises the steps of arranging a third plurality of heat exchangers operatively associated with the third selected function on the third module base to form a portion of the first row of heat exchanger bays and a portion of the second row of heat exchanger bays, the third plurality of heat exchangers being arranged on an elevated level vertically offset from the third module base to provide a covered section of 20 the third module base. In one form, the process further comprises the steps of sizing the third module base such that the third plurality of heat exchangers covers at least 90% of the third module base to form a fully covered third module. 25 In one form, the process further comprises the step of constructing at least one of the plurality of modules at a construction location or assembling at least one of the plurality of modules at an assembly location prior to transport to the production location, and testing the at least one module for verification purposes at the construction or assembly 30 location. In one form, the first module is one of a plurality of first modules. In one form, the second -9 module is one of a plurality of second modules. In one form, one of the plurality of modules is a pre-treatment module for removing contaminants from a natural gas feed stream to produce a pre-treated natural gas stream. 5 In one form, one of the plurality of modules is a first refrigerant condenser module for pre-cooling a pre-treated natural gas stream to produce a pre-cooled gas stream and a first refrigerant vapour stream. 10 In one form, one of the plurality of modules is a first refrigerant compression module for compressing a first refrigerant vapour stream to produce a compressed first refrigerant stream for recycle to a first refrigerant condenser module. In one form, one of the plurality of modules is a liquefaction module operatively 15 associated with a main cryogenic heat exchanger for further cooling a pre-cooled gas stream through indirect heat exchange with a second refrigerant to produce a liquefied natural gas product stream and a second refrigerant vapour stream. In one form, one of the plurality of modules is a second refrigerant compression module 20 for compressing a second refrigerant vapour stream to produce a compressed second refrigerant stream for recycle to a main cryogenic heat exchanger. In one form, the second refrigerant compression module is a partially covered module having a first uncovered section of the base on a first side of the heat exchanger bank and 25 a second uncovered section of the module on a second side of the heat exchanger bank after installation at the production location and wherein a first refrigerant compressor is arranged on the first uncovered section and a second refrigerant compressor is arranged on the second uncovered section. 3 0 In one form, the first refrigerant is propane or nitrogen. In one form, the second refrigerant is a mixed refrigerant hydrocarbon mixture or nitrogen.

- 10 In one form, each of the plurality of modules is substantially equally sized. In one form, the production location is onshore, offshore on a floating facility, offshore on a fixed facility, barge-mounted or grounded facility. 5 In one form, the heat exchangers are air-cooled heat exchangers. According to a third aspect of the present invention there is provided a product stream of liquefied natural gas at a production location, said process comprising: 10 designing or constructing a plurality of spaced-apart modules for installation at a production location to form a production train, the production train having a central longitudinal axis, each module having a module base for mounting a plurality of plant equipment associated with a selected function assigned to said module, the plurality of modules including at least; a first module assigned to perform a first selected function, 15 and, a second module assigned to perform a second selected function; positioning the first module base parallel to and axially offset in a first direction relative to the central longitudinal axis of the production train; positioning the second module base adjacent to the first module base such that the second module is parallel to and axially offset in a second opposing direction relative to 20 the central longitudinal axis of the production train; and, positioning a common services module parallel to the central longitudinal axis of the production train, the common services module being axially offset from the central longitudinal axis of the production train in either: i) the first direction relative to the central longitudinal axis of the production train 25 wherein the common services module is arranged to cross over the first module base but not the second module base; or, ii) the second direction relative to the central longitudinal axis of the production train wherein the common services module is arranged to cross over the second module base but not the first module base. 30 In one form, the process further comprises the steps of arranging a first plurality of heat exchangers operatively associated with the first selected function on the first module base - 11 to form a first sub-section of the first row of heat exchanger bays, the first plurality of heat exchangers being arranged on an elevated level vertically offset from the first module base to provide a covered section of the first module base. 5 In one form, the process further comprises the step of sizing the first module base to include a covered section for mounting of the first plurality of heat exchangers and an uncovered section for mounting a selected piece of process equipment. In one form, the selected piece of equipment is; a rotating piece of equipment associated with a circulating refrigerant, a piece of equipment having a flammable inventory, a long lead-time piece of 10 equipment, or, a piece of equipment having an overall height that is taller than the height of the elevated level. In one form, the process further comprises the steps of arranging a second plurality of heat exchangers operatively associated with the second selected function on the second module 15 base to form a first sub-section of the second row of heat exchanger bays, the second plurality of heat exchangers being arranged on an elevated level vertically offset from the second module base to provide a covered section of the second module base. In one form, the process further comprises the step of sizing the second module base to 20 include a covered section for mounting of the second plurality of heat exchangers and an uncovered section for mounting a selected piece of process equipment. In one form, the selected piece of equipment is; a rotating piece of equipment associated with a circulating refrigerant, a piece of equipment having a flammable inventory, a long lead-time piece of equipment, or, a piece of equipment having an overall height that is taller than the height 25 of the elevated level. In one form, the process further comprises the steps of arranging a third plurality of heat exchangers operatively associated with the third selected function on the third module base to form a portion of the first row of heat exchanger bays and a portion of the second 30 row of heat exchanger bays, the third plurality of heat exchangers being arranged on an elevated level vertically offset from the third module base to provide a covered section of the third module base.

- 12 In one form, the process further comprises the steps of sizing the third module base such that the third plurality of heat exchangers covers at least 90% of the third module base to form a fully covered third module. 5 In one form, the process further comprises the step of constructing at least one of the plurality of modules at a construction location or assembling at least one of the plurality of modules at an assembly location prior to transport to the production location, and testing the at least one module for verification purposes at the construction or assembly location. 10 In one form, the first module is one of a plurality of first modules. In one form, the second module is one of a plurality of second modules. In one form, one of the plurality of modules is a pre-treatment module for removing 15 contaminants from a natural gas feed stream to produce a pre-treated natural gas stream. In one form, one of the plurality of modules is a first refrigerant condenser module for pre-cooling a pre-treated natural gas stream to produce a pre-cooled gas stream and a first refrigerant vapour stream. 20 In one form, one of the plurality of modules is a first refrigerant compression module for compressing a first refrigerant vapour stream to produce a compressed first refrigerant stream for recycle to a first refrigerant condenser module. 25 In one form, one of the plurality of modules is a liquefaction module operatively associated with a main cryogenic heat exchanger for further cooling a pre-cooled gas stream through indirect heat exchange with a second refrigerant to produce a liquefied natural gas product stream and a second refrigerant vapour stream. 30 In one form, one of the plurality of modules is a second refrigerant compression module for compressing a second refrigerant vapour stream to produce a compressed second refrigerant stream for recycle to a main cryogenic heat exchanger.

- 13 In one form, wherein the second refrigerant compression module is a partially covered module having a first uncovered section of the base on a first side of the heat exchanger bank and a second uncovered section of the module on a second side of the heat exchanger bank after installation at the production location and wherein a first refrigerant 5 compressor is arranged on the first uncovered section and a second refrigerant compressor is arranged on the second uncovered section. In one form, the first refrigerant is propane or nitrogen. In one form, the second refrigerant is a mixed refrigerant hydrocarbon mixture or nitrogen. 10 In one form, each of the plurality of modules is substantially equally sized. In one form, the production location is onshore, offshore on a floating facility, offshore on a fixed facility, barge-mounted or grounded facility. 15 In one form, the heat exchangers are air-cooled heat exchangers. BRIEF DESCRIPTION OF THE DRAWINGS In order to facilitate a more detailed understanding of the nature of the invention several 20 embodiments of the present invention will now be described in detail, by way of example only, with reference to the accompanying drawings, in which: FIG. 1 is a schematic plan view of a prior art production train; FIG. 2 (a) is an isometric view from one direction of one of the plurality of modules of an LNG production train of the present invention; 25 FIG. 2 (b) is a plan view of the module of FIG. 2(a); FIG. 3 is a schematic plan view of one embodiment of the present invention including a common services module; FIG. 4(a) is a schematic plan view of one embodiment of the present invention in which the entire first row of heat exchanger bays is shaded in light grey; 30 FIG. 4(b) is a schematic plan view of one embodiment of the present invention in which a first sub-section of the first row of heat exchanger bays is shaded in light grey.

- 14 FIG. 4(c) is a schematic plan view of one embodiment of the present invention in which the shaded portion of FIG. 4(c) illustrates a second plurality of heat exchangers operatively associated with the second selected function on the second module base; FIG. 5 is a schematic plan view of one embodiment of the present invention 5 including a common services module arranged over the second modules; FIG. 6 is a schematic plan view of one embodiment of the present invention including a common services module arranged over the first modules; FIG. 7 is a schematic plan view of one embodiment of the present invention; FIG. 8 is a schematic plan view of one embodiment of the present invention 10 including two pretreatment modules; FIG. 9 is a schematic plan view of one embodiment of the present invention wherein the first module is one of two first modules and the second module is one of two second modules; FIG. 10 is a schematic plan view of one embodiment of the present invention; 15 FIG. 11 is a schematic plan view of one embodiment of the present invention; FIG. 12 is a schematic plan view of one embodiment of the present invention; FIG. 13 is a schematic plan view of one embodiment of the present invention; and, FIG. 14 is a schematic plan view of one embodiment of the present invention including a second refrigerant compressor located off-module. 20 DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS The present invention may be understood more readily by reference to the following detailed description of the invention taken in connection with the accompanying drawing figures, which form a part of this disclosure. It is to be understood that the present 25 invention is not limited to the specific devices, methods, conditions or parameters described and/or shown herein, and that the terminology used herein is for the purpose of describing particular embodiments by way of example only and is not intended to be limiting of the claimed invention. Also, as used in the specification including the appended claims, the singular forms "a," "an," and "the" include the plural, and reference 30 to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in - 15 the art to which this invention belongs. Like reference numerals refer to like parts. The term "LNG" refers to liquefied natural gas. 5 The term "production train" refers to facilities used for the pre-treatment of a natural gas feed stream to remove contaminants and facilities used for receiving pre-treated gas and subjecting the pre-treated gas to cooling to form liquefied natural gas. The term "heat exchanger bay" refers to a heat exchanger having a plurality of tubes 10 extending between flow headers with fluid being cause to flow through the plurality of tubes to exchange heat with a heat exchange medium that passes across the outside of the plurality of tubes. When the heat exchanger bay is an air-cooled heat exchanger bay, a plurality of fans is arranged within each heat exchanger bay between the headers to direct the flow of air across the plurality of tubes. 15 The term "heat exchanger bank" refers to a collection of heat exchanger bays arranged adjacent to each other in a single or double row. The term "stick-built" or "off-module" refers to a plant or a section of a plant that is 20 constructed predominantly on a production location which the plant is intended to occupy upon completion of construction of the plant. In contrast, the term "module" refers to a section of a plant that is pre-assembled at a construction or assembly location remote from the production location. Each module is designed to be transported from the construction or assembly location to the production location by towing or on floating barges or by land 25 using rail or truck. After each module is moved from the construction or assembly location to the production location, the module is positioned in a suitable pre-determined orientation to suit the needs of a given LNG production facility. A first embodiment of the present invention is now described with reference to FIGS. 2 to 30 4 which schematically show a liquefied natural gas production process (10) for producing a product stream of liquefied natural gas at a production location (12). The process includes step a) of designing a plurality of modules (14) for installation at the production - 16 location (12) to form a production train (16). An example of one of the plurality of modules is illustrated in FIG. 3. Each module (14) has a module base (18) for mounting a plurality of plant equipment (20) associated with a selected function associated with the production of liquefied natural gas, said selected function being assigned to said module 5 (14). The process includes step b) of arranging the plurality of modules (14) at the production location (12) to form the production train (16), the production train having a central longitudinal axis (22). The number of modules within the plurality of modules may vary. In the embodiment illustrated in FIGS. 3 and 4(a) to 4(3), the production train (16) comprises five modules. In the embodiment illustrated in FIG. 13, the production 10 train (16) comprises eight modules. The plurality of modules (14) includes at least; a first module (24) assigned to perform a first selected function, a second module (26) assigned to perform a second selected function, and a third module (30) assigned to perform a third selected function. In step c), 15 the first module (24) is positioned parallel to and axially offset in a first direction (depicted by the upward arrow labelled with reference numeral (32) in FIG. 3 relative to the central longitudinal axis (22) of the production train (16). In step d), the second module (26) is positioned adjacent to the first module (24) such that the second module (26) is parallel to and axially offset in a second opposing direction (depicted by the 20 downward arrow labelled with reference numeral (34) in FIG. 3 relative to the central longitudinal axis (22) of the production train (16). In step e), the third module (30) is positioned parallel to and in co-alignment with the central longitudinal axis (22) of the production train (16). In this arrangement, the third module (30) is in direct fluid communication with both the first module (24) and the second module (26). In step f), a 25 selected feed rate of natural gas is processed in the production train to produce the product stream of liquefied natural gas (LNG). It is to be clearly understood that steps c) may take place prior to step d) or after step d). Advantageously, steps c) and d) can occur simultaneously to reduce the construction schedule if both the first module and the second module are available for installation at the production location at the same time. 30 The process of the present invention provides a number of advantages over the prior art. Using the prior art arrangement illustrated in FIG. 1, each of the Prior Art Modules A, B, - 17 C, D, and E need to be installed in sequence along the length of the production train. If there was any delay in the construction of Prior Art Module B, the installation of one or both of Prior Art Modules A and C at the production would similarly be delayed. Using the process of the present invention, by axially offsetting each of the first module and the 5 second module in opposing directions relative to the central longitudinal axis of the production train, installation of the first module (24) is independent of installation of the second module (26) providing a significant reduction in the project construction schedule. Using the prior art arrangement illustrated in FIG. 1, any flow of fluid between Prior Art 10 Module A and Prior Art Module C was required to pass through Prior Art Module B, unnecessarily increasing the complexity of design of Prior Art Module B. Using the process of the present invention, by axially offsetting each of the first module and the second module in opposing directions relative to the central longitudinal axis of the production train, the third module (30) is arranged to allow direct fluid communication 15 with both the first module (24) and the second module (26) independently. This provides significant savings in the construction and commissioning schedule of the LNG production train in that as soon as the first module arrives on site and positioned according to step c), fluid communication between the first module (24) and the third module (30) can be established and verified without being affected by any delay in the 20 construction of the second module (26) or any delay in the delivery of the second module (26) to the production location (12). Analogously, if there is any delay in the construction of the first module (24) or any delay in the delivery of the first module (24) to the production location (12), the second module (26) can be positioned according to step d) so that fluid communication between the second module (26) and the third module (30) can 25 be established and verified without being affected by any delay in the delivery of the first module (24). The process of the present invention further comprises the step of designing a heat exchanger bank (36) having a central longitudinal axis (38) parallel to the central 30 longitudinal axis of the production train (22), the heat exchanger bank (36) including: a first row of heat exchanger bays (40) parallel to and axially offset in the first direction (32) relative to the central longitudinal axis of the heat exchanger bank; and, an adjacent - 18 second row of heat exchanger bays (42) parallel to and axially offset in the second direction (34) relative to the central longitudinal axis of the heat exchanger bank. Using this arrangement, first module (24) is arranged within the production train (16) to include a first sub-section (44) of the first row of heat exchanger bays (40) without including a 5 sub-section of the second row of heat exchanger bays (42) as best illustrated in FIG. 4(a), described in greater detail below. Using the prior art arrangement illustrated in FIG. 1, the heat exchanger bank (6) was similarly made up of a first row of heat exchanger bays (7) and a second row of heat 10 exchanger bays (8). However, using the prior art arrangement of FIG. 1, each and all of the Prior Art Modules A, B, C, D, and E included a section of both the first and second rows of heat exchanger bays. In contrast, using the process of the present invention, the major axis of the first module (24) and the second module (26) is rotated at right angles to the arrangement of the prior art shown in FIG. 1. For clarity purposes, FIG. 4(a) shows 15 the production train of FIG. 3 with the entire first row of heat exchanger bays (40) shaded in light grey while in FIG. 4(b), only the first sub-section (44) of the first row of heat exchanger bays (40) is shaded in light grey. It is apparent from the embodiments of the present invention illustrated in FIG. 4(a) and 4(b), that the first module (24) includes a section of the first row of heat exchanger bays (40) without including any section of the 20 second row of heat exchanger bays (42). As set out above, the plurality of modules (14) includes at least; a first module (24) assigned to perform a first selected function, a second module (26) assigned to perform a second selected function, and a third module (30) assigned to perform a third selected 25 function. With reference to Figure 2(a), the process of the present invention includes the step of arranging a first plurality of heat exchangers (46) operatively associated with the first selected function on a first module base (48) to form a portion of the first sub-section (44) of the first row of heat exchanger bays (40), the first plurality of heat exchangers being arranged (46) on an elevated level (50) vertically offset from the first module base 30 to provide a covered section (52) of the first module base (48). This arrangement is used to minimize the plot space required for the production train (16).

- 19 In the embodiment illustrated in FIG. 5, the process includes the step of sizing the first module base (48) to include a covered section (52) for mounting of the first plurality of heat exchangers (46) and an uncovered section (54) for mounting a selected piece of process equipment (55). The selected piece of equipment may be selected from the group 5 including, but not limited to: a rotating piece of equipment associated with a circulating refrigerant, a piece of equipment having a flammable inventory, a long lead-time piece of equipment, or, a piece of equipment having an overall height that is taller than the height of the elevated level (50). As can be seen from FIG. 5, when the first module (24) is installed at the production location, the covered section (52 )is positioned closest to the 10 central longitudinal axis (38) of the heat exchanger bank (36) so that first plurality of heat exchangers are aligned with the first row of heat exchanger bays (40). The uncovered section (54) of the first module base (24) is positioned away from the central longitudinal axis of the heat exchanger bank in the first direction (32). The uncovered section of the first module base is provided to allow unobstructed overhead crane access to the selected 15 pieces of equipment as well as improved side access making construction or maintenance activities for the selected pieces of equipment easier to perform. Sizing the first module base to include an uncovered section in addition to the covered section, allows for installation and positioning of the selected pieces of equipment in a less congested area of the module which has the flow-on benefit of allowing the selected pieces of equipment to 20 be the last pieces of equipment that are installed on the module. In an analogous manner with particular reference to the shaded portion of FIG. 4(c) and the embodiment illustrated in FIG. 6, the process includes the step of arranging a second plurality of heat exchangers (56) operatively associated with the second selected function 25 on the second module base (58) to form a first sub-section (60) of the second row of heat exchanger bays (42), the second plurality of heat exchangers (56) being arranged on an elevated level (50) vertically offset from the second module base (58) to provide a covered section (62) of the second module base. In the event that there is insufficient space available on the second module base (58) to accommodate the required duty of the 30 second plurality of heat exchangers (56), a second sub-section (59) of the second row of heat exchanger bays (42) may be positioned on the adjacent third module (30) as illustrated by the shaded area of the embodiment illustrated in FIG. 4(c). By way of - 20 example, the second module may be a propane condenser module which requires a large number of heat exchangers to be included in the second plurality of heat exchangers (56). It can be clearly seen from FIGS 4a) to 4c) that the process includes arranged the plurality 5 of heat exchangers on each module so that when step a) is performed and the plurality of modules are arranged at the production location to form the production train, the first, second and third plurality of heat exchangers are aligned to form the heat exchanger bank (36) with the first row of heat exchanger bays (40) running in parallel alignment with the second row of heat exchanger bays (42). 10 In the embodiment illustrated in FIG. 6, the process includes the step of sizing the first module base (48) to include a covered section (52) for mounting of the first plurality of heat exchangers (46) and an uncovered section (54) for mounting a selected piece of process equipment as described above with reference to FIG. 5. In addition to this, in the 15 embodiment illustrated in FIG. 6, the process includes the step of sizing the second module base (58) to include a covered section (62) for mounting of the second plurality of heat exchangers (56) and an uncovered section (64) for mounting a selected piece of process equipment (55). As above, the selected piece of equipment may be selected from the group including, but not limited to: a rotating piece of equipment associated with a 20 circulating refrigerant, a piece of equipment having a flammable inventory, a long lead time piece of equipment, or, a piece of equipment having an overall height that is taller than the height of the elevated level (50). As can be seen from FIG. 6, when the second module is installed at the production location, the covered section is positioned closest to the central longitudinal axis of the heat exchanger bank so that second plurality of heat 25 exchangers are aligned with the first row of heat exchanger bays. The uncovered section of the second module base is positioned away from the central longitudinal axis of the heat exchanger bank in the second direction (34). In an analogous manner, with reference to FIG. 5, the process further comprises the step 30 of arranging a third plurality of heat exchangers (66) operatively associated with the third selected function on the third module base (68) to form a second sub-section (70) of the first row of heat exchanger bays (40) and a second sub-section (72) of the second row of -21 heat exchanger bays (42), the third plurality of heat exchangers being arranged on an elevated level (50) vertically offset from the third module base (68) to provide a covered section (74) of the third module base (68). In this manner, the third module (30) includes both the first and second rows of heat exchanger bays. In contrast, the first module (24) 5 does not include any sub-section of the second row of heat exchanger bays (42) and the second module (26) does not include any sub-section of the first row of heat exchanger bays (40), greatly reducing the number of interconnections between modules compared with the prior art production facility illustrated in FIG. 1. The process includes the step of sizing the third module base (68) such that the third plurality of heat exchangers (66) 10 covers at least 90% of the third module base (68) to form a fully covered third module. The process of the present invention includes the step of constructing at least one of the plurality of modules at a construction location or assembling at least one of the plurality of modules at an assembly location prior to transport to the production location, and 15 testing the at least one module for verification purposes at the construction or assembly location. Within each module, the pieces of equipment required to perform the pre determined function assigned to that module are arranged to minimize interfaces between modules so as to minimize the hook-up that is required to be completed when the modules are delivered from a construction location or assembly location to the production location. 20 In this way, a module can be essentially self-contained and provided with a temporary control system to allow the module to be switched on for loop checks and commissioning at the construction or assembly location prior to transport to the production location. Upon arrival at the production location, wireless control may be used for inter-modular communication and control to further reduce the hook-up time. At a production location 25 where it is important to minimize the length of interconnecting pipe runs between modules, the plurality of modules are spaced as closely as possible, while still allowing sufficient room at the production location to hook up the interconnections between modules. 30 Alternative embodiments are illustrated in FIGS. 7 to 14 for which like reference numerals refer to like parts. The various features included in these alternative embodiments are now described in detail. To the extent that the function and design of - 22 the first, second and third module are not described below in relation to FIGS. 7 to 14, the first, second and third module perform the same function and have the same design as described above in relation to the embodiments illustrated in FIGS. 4 to 6. 5 FIGS. 7 and 8 illustrate embodiments in which the second module base (58) may be of a different length to the first module base (48) while in FIGS 4(a) and 5, the first module base had substantially the same length as the second module base. FIGS. 7, 8 and 12 further illustrate that the third module (30) may be positioned at an outlet end (80) of the production train (16). When the third selected function is liquefaction, then positioning 10 the third module (30) at the output end (80) of the production train (16) minimises the length of the run of product pipe between the production train and an LNG product storage tank (82). FIG. 9 and 14 each illustrates that the first module may be one of a plurality of first modules and that the second module may be one of a plurality of second modules. 15 In FIG. 10 and FIG 11, the production train (16) includes a fourth module (84) and a fifth module (86), each of the fourth and fifth modules being designed to include a sub-section of the first row of heat exchanger bays and a sub-section of the second row of heat exchanger bays. In the embodiment illustrated in FIG. 10, both the fourth module and the 20 fifth module include a covered section (88) and an uncovered section (90). The uncovered sections (90) are provided for mounting of selected pieces of equipment in an analogous manner to that described above for other modules that are sized to include covered and uncovered sections. In the embodiment illustrated in FIG. 11, each of the fourth and fifth modules is sized to include a first uncovered section (92) in the first 25 direction (32) and a second uncovered section (94) in the second direction (34). In this embodiment, the first uncovered section (92) is sized for mounting a first selected piece of process equipment (96) and the second uncovered section (94) is sized for mounting a second selected piece of process equipment (98). 30 One embodiment of the use of the production train (16) for the production of LNG is now described. In general terms, a process for liquefying a natural gas stream comprises the steps of: - 23 i) pre-treating a natural gas feed stream in a pre-treatment module (100) to produce a pre-treated natural gas stream; ii) pre-cooling the pre-treated natural gas stream in a first refrigerant condenser module (102) to produce a pre-cooled gas stream and a first refrigerant vapour stream; 5 iii) compressing the first refrigerant vapour stream in a first refrigerant compression module (104) to produce a compressed first refrigerant stream for recycle to step ii); iv) further cooling the pre-cooled gas stream in a main cryogenic heat exchanger (106) operatively associated with a liquefaction module (108) through indirect heat exchange with a second refrigerant to produce a liquefied natural gas product stream and 10 a second refrigerant vapour stream; and, v) compressing the second refrigerant vapour stream in a second refrigerant compression module (110) to produce a compressed second refrigerant stream for recycle to step iv). 15 In the detailed description of one embodiment of the production train below, the first refrigerant is propane while the second refrigerant is a mixed refrigerant hydrocarbon mixture. This type of process is known as the propane pre-cooled mixed refrigerant, or C3MR process, which is used to manufacture most of the LNG produced worldwide and is a process that is not further discussed here is it considered to be well known to the 20 person skilled in the art. In the embodiments illustrated in FIGS 4 to 14, the production train (16) comprises at least the following modules: a) a pretreatment module (100); 25 b) a first refrigerant compression module (102), in this example, a propane compression module; c) a first refrigerant condenser module (104), in this example, a propane condenser module; d) a liquefaction module (108); and, 30 e) a second refrigerant compression module (110), in this example, a mixed refrigerant (MR) compression module.

- 24 When using propane as the first refrigerant, care is taken to ensure that propane does not leak because propane vapour is highly flammable. Using the process of the present invention, the process equipment required for propane compression is grouped together within a propane compression module to facilitate the pre-commissioning and 5 commissioning of that module - having all of the accessories that are needed to circulate fluid through the compressor at the construction or assembly location. To further improve safely, the main rotating equipment associated with the propane compression circuit is placed on an uncovered section of one of the plurality of modules s rather than underneath the plurality heat exchangers arranged on the elevated level. 10 In the embodiment illustrated in FIG. 3, the pretreatment module (100) is a first module (24), the first refrigerant compression module (102) is a second module, and the first refrigerant condenser module (104) is a third module. In addition to this the liquefaction module (108) is a first module (24) and the second refrigerant compression module (110) 15 is a second module. In terms of construction scheduling, the compressors are long lead items. This embodiment allows for the installation of the pretreatment module (100) and first refrigerant condenser module (104) to occur at the production location (12) without needing to wait for the installation of the first refrigerant compression module (102). In an analogous manner, the liquefaction module (108) can be installed at the production 20 location (12) without the need to wait of the installation of the second refrigerant compression module (110). In addition to this the liquefaction module (108) is a first module (24) and the second refrigerant compression module (110) is a second module. This arrangement allows for direct fluid communication between the first refrigerant compression module (102) and the first refrigerant condenser module (104) without the 25 need for the propane to be piped across the pretreatment module (100). This arrangement further allows for direct fluid communication between the liquefaction module (108) and the LNG storage tank (82) without the need for the LNG produced to pass through the second refrigerant compression module (110). 30 In the embodiments illustrated in FIG. 6, 9, 10, 11 and 14, the pre-treatment module is a first module (24) and the first module base (48) is sized to include a covered section (52) for mounting of the first plurality of heat exchangers (46) and an uncovered section (54) - 25 for mounting a selected piece of process equipment (55), such as an acid gas removal unit column and its associated knock-out vessel and pumps. The pre-treatment module (100) is located at an inlet end (116) of the production train (16) to provide ease of connection to an inlet stream of natural gas being fed to the pre-treatment module (100). 5 In the embodiments illustrated in FIG.5, 6, and 9 to 14, the propane compression module (102) is a second module (26). The second module base (58) is sized to include a covered section (62) for mounting of the second plurality of heat exchangers (56) and an uncovered section (64) for mounting a selected piece of process equipment (55), such one 10 or more propane compressors. In the embodiments illustrated in FIG. 3, 5, 6, 9, 10, 11, and 14, the propane condenser module (104) is a third module because this module requires a comparatively large number of heat exchangers to be included in the third plurality of heat exchangers 15 compared with the other modules. In these embodiments, the propane condenser module (104) is aligned with the central longitudinal axis of the heat exchanger bank (36) to accommodate its requirement to include a sub-section of the first row of heat exchanger bays (40) and a sub-section of the second row of heat exchanger bays (42). The steam system and cooling water system equipment associated with the pre-determined function 20 being performed by the propane condenser module can be safely located under the third plurality of heat exchangers covering the propane condenser module (104) as these inventories are non-flammable. The selected function being performed by the propane condenser module includes pre-cooling of the natural gas using propane. The propane condenser module (104) is conveniently positioned to allow direct fluid communication 25 between the propane condenser module (104) and both of the propane compression module (102) and the liquefaction module (108) so that the pre-treated natural gas can be pre-cooled prior to liquefaction. In the illustrated embodiments, the liquefaction module (108) is a first module (see FIG. 6 30 and 14), a second module (see FIG. 5) or a third module (see FIGS. 7, 8 and 12). The process may include the step of locating the main cryogenic heat exchanger (106) off module adjacent to the propane condenser module (104) or adjacent to the liquefaction - 26 module (108) due to its size and weight and to mitigate the potential for damage during transport. Static equipment and pumps which are operatively associated with the main cryogenic heat exchanger (106) are positioned on the liquefaction module (108) on the same side of the heat exchanger bank as the main cryogenic heat exchanger (106) to 5 minimise interconnecting piping runs. If the decision is made to position the main cryogenic heat exchanger (106) on the liquefaction module (108), the liquefaction module (108) is a first module (24) and the first module base (48) is sized to include a covered section (52) for mounting of the first plurality of heat exchangers (46) and an uncovered section (54) for mounting a selected piece of process equipment (55), such as a steam 10 driven end-flash gas compressor to allow easy overhead crane access to the end flash compressor. Equipment associated with nitrogen and helium removal may also be positioned in the liquefaction module if required. If required, a subset of heat exchangers operatively associated with the propane condenser 15 module may span across to partially cover the module base of the adjacent liquefaction module. The end-flash gas compressor requires only very few heat exchangers with the result that the liquefaction module has space available for additional heat exchangers. The service that needs additional space is the propane condenser which makes positioning the liquefaction module adjacent to the propane condenser module advantageous. 20 In the embodiments illustrated in FIGS. 3, 6, and 12, the second refrigerant (MR) compression module (110) is a second module. In the embodiments illustrated in FIGS. 5, 7 and 9, the second refrigerant (MR) compression module (110) is a first module. The mixed refrigerant compression module includes all of the process equipment required to 25 perform the functional requirement of this module including the gas turbine, the compressor, interconnecting pipework, waste heat recovery, and recycle valves which are arranged on the module base. The plurality of heat exchangers operatively associated with the MR compression module provides the required aftercooling and intercooling for the mixed refrigerant compressors. In this embodiment, the second compression module 30 (110) is a first module including an uncovered section of sufficient size to accommodate a high pressure (HP) mixed refrigerant compressor (122) adjacent to a low pressure (LP) mixed refrigerant compressor (124). The compressors associated with the second -27 refrigerant compression module (110) are long lead items. By positioning the second refrigerant compression module at the outlet end of the production train, the other modules can be transported to and installed at the production site and hooked up first if there is a delay in the delivery of the MR compressors. Advantageously, by offsetting the 5 second refrigerant compression module (110) and the liquefaction module (108), the run of mixed refrigerant piping from the second refrigerant compression module (110) to the propane kettles located on or adjacent to the propane compression module (104) is kept to a minimum. 10 Each module has been designed to ensure that the main hydrocarbon inventories and all rotating equipment are positioned on the uncovered sections of the modules and not underneath the elevated heat exchanger bank. This permits good access for maintenance and allows the long lead items to be incorporated into the modules late in the construction sequence. The significantly reduced hydrocarbon inventory provides improved safety by 15 way of making it easier to deal with the consequence of a leak. In addition to this, the overall layout of the production train of the present invention is designed to for modularisation, with small compact equipment selected to suit modularisation rather than adopting the prior art approach of relying on economy of scale. Instead, smaller, more intensive equipment has been selected in order to be able to fit more items inside modules 20 of a limited size and weight. One example of selecting smaller, more intensive equipment that is easier to modularise is the main refrigerant gas turbines. The starting point for this work was to utilise smaller more efficient aero-derivative gas turbines that can be completely integrated into modules of a practical size. Aero-derivative gas turbines have been integrated into the modules, complete with the all of the elements of each 25 compression system. This permits the complicated, large-diameter compressor suction and discharge lines to be built in at a construction location rather than having to be stick built at the production location, whilst retaining a practical total module size/weight. Using smaller units and keeping the gas turbine and compressor integrated in the same module minimises the number of connections at site, and it also makes it possible for the 30 compression system to be fully tested up to a nitrogen test run stage at the construction or assembly location. This extra level of commissioning and testing at the construction or assembly location is beneficial in reducing the amount of carry-over work that has to be - 28 done at a significantly higher labour rate at the production site. The variable speed nature of the aero-derivative gas turbines simplifies the compressor start-up and eliminates the need to depressurise refrigerant. Removing the need for starter/helper motors for gas turbines used in prior art LNG trains also significantly reduces the maximum electrical 5 power demand of the modularized LNG train and helps to keep the module size down. With reference to the embodiment illustrated in FIG. 3, the production train (16) is further provided with a common services module (130) extending for a first end (132) of the production train to a second end (134) of the production train. The common services 10 module includes equipment that may be required by a plurality of modules including electrical services, water services, control signals, or gas services. One example of a 'common service' is the flare header. Using the system and process of the present invention, the common services module is 15 arranged to cross less than all of the plurality of modules (14). In the embodiment illustrated in FIG. 3, the common services module (130) is positioned parallel to and axially offset in the first direction (32) relative to the central longitudinal axis (22) of the production train (16) wherein the common services module does not pass through any second module (26). In this embodiment, it is particularly advantageous to ensure that the 20 first refrigerant compression module (102) is a second module (26) and that the second refrigerant compression module (110) is a second module (26) so that the common services module (130) does not pass through the first refrigerant compression module (102) or the second refrigerant compression module (110). Alternatively, in the embodiment illustrated in FIG. 5, the common services module (130) is positioned 25 parallel to and axially offset in the second direction (34) relative to the central longitudinal axis (22) of the production train (16) wherein the common services module does not pass through any first module (24). In this embodiment, it is particularly advantageous to ensure that the first refrigerant compression module (102) is a first module (24) and that the second refrigerant compression module (110) is a first module 30 (24) so that the common services module (130) does not pass through the first refrigerant compression module (102) or the second refrigerant compression module (110).

- 29 Ensuring that the common services module (130) does not pass through either of the first refrigerant compression module (102) or the second refrigerant compression module (110) provides three advantages over the prior art. The first advantage is that the design of the first refrigerant compression module (102) and the second refrigerant compression 5 module (110) is simplified as there is no need to include a provision for common services to pass through either the first refrigerant compression module (102) or the second refrigerant compression module (110). Secondly, the overall construction schedule can be shorter because the common service module (130) can be completed independently of the completion of the first refrigerant compression module (102) and the second refrigerant 10 compression module (110). The compression equipment can be a long lead item, delaying the completion of the first refrigerant compression module (102) or the second refrigerant compression module (110). This allows one or both of the first refrigerant compression module (102) and the second refrigerant compression module (110) to be fully constructed and commissioned at a construction location remote from the production 15 location because the only equipment located on these modules is equipment associated with refrigerant compression. Using the prior art arrangement illustrate in FIG. 1, any common services (9) that need to run along the full length of the production train pass through each and all of the Prior Art 20 Modules A, B, C, D and E. Using a flare header as one example of a common service, the prior art arrangement illustrated in FIG. 1 required that a section of the flare header was included on each of the Prior Art Modules A, B, C, D and E which increased the number of inter-module connections that needed to be made on-site after installing of each of the Prior Art Modules A, B, C, D and E, and added to the complexity of each the Prior Art 25 Modules A, B, C, D and E. Using the process and system of the present invention, the common services module (130) is designed to run only along those modules that are covered by at least a sub-section of either the first row of heat exchanger bays (40) or the second row of heat exchanger bays (42), but not both. 30 The production location can be onshore, offshore on a floating facility, offshore on a fixed facility, or a barge-mounted or grounded facility. By way of example, the modules may be floated-in using steel or concrete gravity based structures with integrated LNG storage, - 30 loading and boil-off gas re-liquefaction functionality with gas supplied to the production location via a subsea pipeline. The plurality of heat exchangers in the heat exchanger bank may be air coolers or water coolers. Alternatively, water coolers may be used for at least one module with air coolers used for at least one other module. The LNG plant may 5 further include optional treatment steps such as product purification steps (helium removal, nitrogen removal) and non-methane product production steps (de-ethanizing, de propanizing, sulphur recovery) if desired. The natural gas feed stream may be produced at and obtained from a natural gas or petroleum reservoir. As an alternative, the natural gas feed stream may also be obtained from another source, also including a synthetic source 10 such as a Fischer-Tropsch process wherein methane is produced from synthesis gas. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents forms part of the common general knowledge in the art, in Australia or in any other 15 country. In the summary of the invention, the description and claims which follow, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the 20 invention.

Claims

1. A liquefied natural gas production process for producing a product stream of liquefied natural gas at a production location, said process comprising: 5 a) designing a plurality of modules for installation at the production location to form a production train, each module having a module base for mounting a plurality of plant equipment associated with a selected function associated with the production of liquefied natural gas, said selected function being assigned to said module; b) arranging the plurality of modules at the production location to form the 10 production train, the production train having a central longitudinal axis, the plurality of modules including at least; a first module assigned to perform a first selected function, a second module assigned to perform a second selected function, and a third module assigned to perform a third selected function; c) positioning the first module base parallel to and axially offset in a first direction 15 relative to the central longitudinal axis of the production train; d) positioning the second module base adjacent to the first module base such that the second module is parallel to and axially offset in a second opposing direction relative to the central longitudinal axis of the production train; and, e) positioning the third module base parallel to and in co-alignment with the central 20 longitudinal axis of the production train wherein the third module is in direct fluid communication with the first module and the second module; and, f) processing a selected feed rate of natural gas in the production train to produce the product stream of liquefied natural gas. 25

2. The process of claim 1 further comprising the step of designing a heat exchanger bank having a central longitudinal axis parallel to the central longitudinal axis of the production train, the heat exchanger bank including: a first row of heat exchanger bays parallel to and axially offset in a first direction relative to the central longitudinal axis of 30 the heat exchanger bank; and, an adjacent second row of heat exchanger bays parallel to and axially offset in a second direction relative to the central longitudinal axis of the heat exchanger bank, wherein the first module includes a first sub-section of the first row of heat exchanger bays without including a sub-section of the second row of heat exchanger - 32 bays.

3. The process of claim 1 or 2 further comprising the steps of arranging a first plurality of heat exchangers operatively associated with the first selected function on the first 5 module base to form a first sub-section of the first row of heat exchanger bays, the first plurality of heat exchangers being arranged on an elevated level vertically offset from the first module base to provide a covered section of the first module base.

4. The process of any one of the preceding claims further comprising the step of sizing 10 the first module base to include a covered section for mounting of the first plurality of heat exchangers and an uncovered section for mounting a selected piece of process equipment.

5. The process of claim 4 wherein the selected piece of equipment is; a rotating piece 15 of equipment associated with a circulating refrigerant, a piece of equipment having a flammable inventory, a long lead-time piece of equipment, or, a piece of equipment having an overall height that is taller than the height of the elevated level.

6. The process of any one of the preceding claims further comprising the steps of 20 arranging a second plurality of heat exchangers operatively associated with the second selected function on the second module base to form a first sub-section of the second row of heat exchanger bays, the second plurality of heat exchangers being arranged on an elevated level vertically offset from the second module base to provide a covered section of the second module base. 25

7. The process of any one of the preceding claims further comprising the step of sizing the second module base to include a covered section for mounting of the second plurality of heat exchangers and an uncovered section for mounting a selected piece of process equipment. 30 - 33 8. The process of claim 7 wherein the selected piece of equipment is; a rotating piece of equipment associated with a circulating refrigerant, a piece of equipment having a flammable inventory, a long lead-time piece of equipment, or, a piece of equipment having an overall height that is taller than the height of the elevated level. 5

9. The process of any one of the preceding claims further comprising the steps of arranging a third plurality of heat exchangers operatively associated with the third selected function on the third module base to form a portion of the first row of heat exchanger bays and a portion of the second row of heat exchanger bays, the third plurality of heat 10 exchangers being arranged on an elevated level vertically offset from the third module base to provide a covered section of the third module base.

10. The process of any one of the preceding claims further comprising the steps of sizing the third module base such that the third plurality of heat exchangers covers at least 90% 15 of the third module base to form a fully covered third module.

11. The process of any one of the preceding claims further comprising the step of constructing at least one of the plurality of modules at a construction location or assembling at least one of the plurality of modules at an assembly location prior to 20 transport to the production location, and testing the at least one module for verification purposes at the construction or assembly location.

12. The process of any one of the preceding claims wherein the first module is one of a plurality of first modules 25

13. The process of any one of the preceding claims wherein the second module is one of a plurality of second modules.

14. The process of any one of the preceding claims wherein one of the plurality of 30 modules is a pre-treatment module for removing contaminants from a natural gas feed stream to produce a pre-treated natural gas stream. -34 15. The process of any one of the preceding claims wherein one of the plurality of modules is a first refrigerant condenser module for pre-cooling a pre-treated natural gas stream to produce a pre-cooled gas stream and a first refrigerant vapour stream. 5 16. The process of any one of the preceding claims wherein one of the plurality of modules is a first refrigerant compression module for compressing a first refrigerant vapour stream to produce a compressed first refrigerant stream for recycle to a first refrigerant condenser module. 10 17. The process of any one of the preceding claims one of the plurality of modules is a liquefaction module operatively associated with a main cryogenic heat exchanger for further cooling a pre-cooled gas stream through indirect heat exchange with a second refrigerant to produce a liquefied natural gas product stream and a second refrigerant vapour stream. 15

18. The process of any one of the preceding claims wherein one of the plurality of modules is a second refrigerant compression module for compressing a second refrigerant vapour stream to produce a compressed second refrigerant stream for recycle to a main cryogenic heat exchanger. 20

19. The process of any one of the preceding claims wherein the second refrigerant compression module is a partially covered module having a first uncovered section of the base on a first side of the heat exchanger bank and a second uncovered section of the module on a second side of the heat exchanger bank after installation at the production 25 location and wherein a first refrigerant compressor is arranged on the first uncovered section and a second refrigerant compressor is arranged on the second uncovered section.

20. The process of any one of the preceding claims wherein the first refrigerant is propane or nitrogen. 30

21. The process of any one of the preceding claims wherein the second refrigerant is a mixed refrigerant hydrocarbon mixture or nitrogen. - 35 22. The process of any one of the preceding claims wherein each of the plurality of modules is substantially equally sized.

23. The process of any one of the preceding claims wherein the production location is 5 onshore, offshore on a floating facility, offshore on a fixed facility, barge-mounted or grounded facility.

24. The process of any one of the preceding claims wherein the heat exchangers are air cooled heat exchangers. 10

25. A liquefied natural gas production process for producing a product stream of liquefied natural gas at a production location, said process comprising: designing or constructing a plurality of spaced-apart modules for installation at a production location to form a production train, the production train having a central 15 longitudinal axis, each module having a module base for mounting a plurality of plant equipment associated with a selected function assigned to said module; and, designing or constructing a heat exchanger bank having a central longitudinal axis parallel to the central longitudinal axis of the production train, the heat exchanger bank including a plurality of heat exchanger bays including at least a first row of heat 20 exchanger bays and a second row of heat exchanger bays, the first and second rows of heat exchanger bays arranged to run parallel to central longitudinal axis of the heat exchanger bank, wherein the plurality of modules includes a first module and said first module is arranged within the production train to include a first sub-section of the first row of heat 25 exchanger bays without including a sub-section of the second row of heat exchanger bays.

26. The process of claim 25 further comprising the steps of arranging a first plurality of heat exchangers operatively associated with the first selected function on the first module base to form a first sub-section of the first row of heat exchanger bays, the first plurality 30 of heat exchangers being arranged on an elevated level vertically offset from the first module base to provide a covered section of the first module base. - 36 27. The process of claim 25 or 26 further comprising the step of sizing the first module base to include a covered section for mounting of the first plurality of heat exchangers and an uncovered section for mounting a selected piece of process equipment. 5 28. The process of claim 27 wherein the selected piece of equipment is; a rotating piece of equipment associated with a circulating refrigerant, a piece of equipment having a flammable inventory, a long lead-time piece of equipment, or, a piece of equipment having an overall height that is taller than the height of the elevated level. 10 29. The process of any one of claim 25 to 28 further comprising the steps of arranging a second plurality of heat exchangers operatively associated with the second selected function on the second module base to form a first sub-section of the second row of heat exchanger bays, the second plurality of heat exchangers being arranged on an elevated level vertically offset from the second module base to provide a covered section of the 15 second module base.

30. The process of any one of claim 25 to 29 further comprising the step of sizing the second module base to include a covered section for mounting of the second plurality of heat exchangers and an uncovered section for mounting a selected piece of process 20 equipment.

31. The process of claim 30 wherein the selected piece of equipment is; a rotating piece of equipment associated with a circulating refrigerant, a piece of equipment having a flammable inventory, a long lead-time piece of equipment, or, a piece of equipment 25 having an overall height that is taller than the height of the elevated level.

32. The process of any one of claim 25 to 31 further comprising the steps of arranging a third plurality of heat exchangers operatively associated with the third selected function on the third module base to form a portion of the first row of heat exchanger bays and a 30 portion of the second row of heat exchanger bays, the third plurality of heat exchangers being arranged on an elevated level vertically offset from the third module base to provide a covered section of the third module base. - 37 33. The process of any one of claim 25 to 32 further comprising the steps of sizing the third module base such that the third plurality of heat exchangers covers at least 90% of the third module base to form a fully covered third module. 5 34. The process of any one of claim 25 to 33 further comprising the step of constructing at least one of the plurality of modules at a construction location or assembling at least one of the plurality of modules at an assembly location prior to transport to the production location, and testing the at least one module for verification purposes at the construction or assembly location. 10

35. The process of any one of claim 25 to 34 wherein the first module is one of a plurality of first modules

36. The process of any one of claim 25 to 35 wherein the second module is one of a 15 plurality of second modules.

37. The process of any one of claim 25 to 36 wherein one of the plurality of modules is a pre-treatment module for removing contaminants from a natural gas feed stream to produce a pre-treated natural gas stream. 20

38. The process of any one of claim 25 to 37 wherein one of the plurality of modules is a first refrigerant condenser module for pre-cooling a pre-treated natural gas stream to produce a pre-cooled gas stream and a first refrigerant vapour stream. 25 39. The process of any one of claim 25 to 38 wherein one of the plurality of modules is a first refrigerant compression module for compressing a first refrigerant vapour stream to produce a compressed first refrigerant stream for recycle to a first refrigerant condenser module. 30 40. The process of any one of claim 25 to 39 one of the plurality of modules is a liquefaction module operatively associated with a main cryogenic heat exchanger for further cooling a pre-cooled gas stream through indirect heat exchange with a second - 38 refrigerant to produce a liquefied natural gas product stream and a second refrigerant vapour stream.

41. The process of any one of claim 25 to 40 wherein one of the plurality of modules is a 5 second refrigerant compression module for compressing a second refrigerant vapour stream to produce a compressed second refrigerant stream for recycle to a main cryogenic heat exchanger.

42. The process of any one of claim 25 to 41 wherein the second refrigerant compression 10 module is a partially covered module having a first uncovered section of the base on a first side of the heat exchanger bank and a second uncovered section of the module on a second side of the heat exchanger bank after installation at the production location and wherein a first refrigerant compressor is arranged on the first uncovered section and a second refrigerant compressor is arranged on the second uncovered section. 15

43. The process of any one of claim 25 to 42 wherein the first refrigerant is propane or nitrogen.

44. The process of any one of claim 25 to 43 wherein the second refrigerant is a mixed 20 refrigerant hydrocarbon mixture or nitrogen.

45. The process of any one of claim 25 to 44 wherein each of the plurality of modules is substantially equally sized. 25 46. The process of any one of claim 25 to 45 wherein the production location is onshore, offshore on a floating facility, offshore on a fixed facility, barge-mounted or grounded facility.

47. The process of any one of claim 25 to 46 wherein the heat exchangers are air-cooled 3 0 heat exchangers. -39

48. A liquefied natural gas production process for producing a product stream of liquefied natural gas at a production location, said process comprising: designing or constructing a plurality of spaced-apart modules for installation at a production location to form a production train, the production train having a central 5 longitudinal axis, each module having a module base for mounting a plurality of plant equipment associated with a selected function assigned to said module, the plurality of modules including at least; a first module assigned to perform a first selected function, and, a second module assigned to perform a second selected function; positioning the first module base parallel to and axially offset in a first direction 10 relative to the central longitudinal axis of the production train; positioning the second module base adjacent to the first module base such that the second module is parallel to and axially offset in a second opposing direction relative to the central longitudinal axis of the production train; and, positioning a common services module parallel to the central longitudinal axis of the 15 production train, the common services module being axially offset from the central longitudinal axis of the production train in either: i) the first direction relative to the central longitudinal axis of the production train wherein the common services module is arranged to cross over the first module base but not the second module base; or, 20 ii) the second direction relative to the central longitudinal axis of the production train wherein the common services module is arranged to cross over the second module base but not the first module base.

49. The process of claim 48 further comprising the steps of arranging a first plurality of 25 heat exchangers operatively associated with the first selected function on the first module base to form a first sub-section of the first row of heat exchanger bays, the first plurality of heat exchangers being arranged on an elevated level vertically offset from the first module base to provide a covered section of the first module base. 30 50. The process of claim 48 or 49 further comprising the step of sizing the first module base to include a covered section for mounting of the first plurality of heat exchangers and an uncovered section for mounting a selected piece of process equipment. - 40 51. The process of claim 50 wherein the selected piece of equipment is; a rotating piece of equipment associated with a circulating refrigerant, a piece of equipment having a flammable inventory, a long lead-time piece of equipment, or, a piece of equipment having an overall height that is taller than the height of the elevated level. 5

52. The process of any one of claims 48 to 51 further comprising the steps of arranging a second plurality of heat exchangers operatively associated with the second selected function on the second module base to form a first sub-section of the second row of heat exchanger bays, the second plurality of heat exchangers being arranged on an elevated 10 level vertically offset from the second module base to provide a covered section of the second module base.

53. The process of any one of any one of claims 48 to 52 further comprising the step of sizing the second module base to include a covered section for mounting of the second 15 plurality of heat exchangers and an uncovered section for mounting a selected piece of process equipment.

54. The process of claim 53 wherein the selected piece of equipment is; a rotating piece of equipment associated with a circulating refrigerant, a piece of equipment having a 20 flammable inventory, a long lead-time piece of equipment, or, a piece of equipment having an overall height that is taller than the height of the elevated level.

55. The process of any one of claims 48 to 54 further comprising the steps of arranging a third plurality of heat exchangers operatively associated with the third selected function 25 on the third module base to form a portion of the first row of heat exchanger bays and a portion of the second row of heat exchanger bays, the third plurality of heat exchangers being arranged on an elevated level vertically offset from the third module base to provide a covered section of the third module base. 30 56. The process of any one of claims 48 to 55 further comprising the steps of sizing the third module base such that the third plurality of heat exchangers covers at least 90% of the third module base to form a fully covered third module. - 41 57. The process of any one of claims 48 to 56 further comprising the step of constructing at least one of the plurality of modules at a construction location or assembling at least one of the plurality of modules at an assembly location prior to transport to the production location, and testing the at least one module for verification purposes at the construction 5 or assembly location.

58. The process of any one of claims 48 to 57 wherein the first module is one of a plurality of first modules 10 59. The process of any one of claims 48 to 58 wherein the second module is one of a plurality of second modules.

60. The process of any one of claims 48 to 59 wherein one of the plurality of modules is a pre-treatment module for removing contaminants from a natural gas feed stream to 15 produce a pre-treated natural gas stream.

61. The process of any one of claims 48 to 60 wherein one of the plurality of modules is a first refrigerant condenser module for pre-cooling a pre-treated natural gas stream to produce a pre-cooled gas stream and a first refrigerant vapour stream. 20

62. The process of any one of claims 48 to 61 wherein one of the plurality of modules is a first refrigerant compression module for compressing a first refrigerant vapour stream to produce a compressed first refrigerant stream for recycle to a first refrigerant condenser module. 25

63. The process of any one of claims 48 to 62 one of the plurality of modules is a liquefaction module operatively associated with a main cryogenic heat exchanger for further cooling a pre-cooled gas stream through indirect heat exchange with a second refrigerant to produce a liquefied natural gas product stream and a second refrigerant 30 vapour stream. - 42 64. The process of any one of claims 48 to 63 wherein one of the plurality of modules is a second refrigerant compression module for compressing a second refrigerant vapour stream to produce a compressed second refrigerant stream for recycle to a main cryogenic heat exchanger. 5

65. The process of any one of claims 48 to 64 wherein the second refrigerant compression module is a partially covered module having a first uncovered section of the base on a first side of the heat exchanger bank and a second uncovered section of the module on a second side of the heat exchanger bank after installation at the production 10 location and wherein a first refrigerant compressor is arranged on the first uncovered section and a second refrigerant compressor is arranged on the second uncovered section.

66. The process of any one of claims 48 to 65 wherein the first refrigerant is propane or nitrogen. 15

67. The process any one of claims 48 to 66 wherein the second refrigerant is a mixed refrigerant hydrocarbon mixture or nitrogen.

68. The process of any one of claims 48 to 67 wherein each of the plurality of modules is 20 substantially equally sized.

69. The process of any one of claims 48 to 68 wherein the production location is onshore, offshore on a floating facility, offshore on a fixed facility, barge-mounted or grounded facility. 25

70. The process of any one of any one of claims 48 to 69 wherein the heat exchangers are air-cooled heat exchangers.