Integrated liquefied natural gas (LNG) production facility on a gravity-based structure (GBS)

Abstract

The invention relates to a production facility and can be used for the development of onshore and offshore integrated liquefied natural gas (LNG) production complexes on gravity-based structures. The LNG production complex comprises a gravity-based structure (GBS) having a GBS top slab, a top module disposed on the GBS top slab, interconnection modules 35-38 along the centerline of the GBS top slab 2, and equipment modules at least partially aligned on each side of the interconnection modules 35-38. Liquid storage tanks 12, 15, 17 are disposed inside the GBS. The equipment modules include a first row on one side of the interconnection modules 35-37, i.e. at least one module 28 of receiving equipment, condensate stabilization equipment and acid gas removal equipment, a first row of at least one module 32 (33) of mixed refrigerant compressors, and a second row on the other side of the interconnection modules 35-37, i.e. modules 29-31 of gas dehydration, mercury removal, wide cut light hydrocarbon extraction, fractionation and liquefaction equipment, and a second row including at least one module 34 of boil-off gas, fuel gas system and heating medium compressors, the equipment modules along the short end of the GBS also include at least one power plant module 39, at least one module 40 with main technical room and emergency diesel generators, and at least one auxiliary system module 41. The invention proposes a solution to the problem of more options for LNG production in coastal waters with thick ice conditions.

Description

[Technical Field]

[0001] The invention relates to production facilities and can be used in the development of integrated onshore and offshore liquefied natural gas (LNG) production complexes on gravity-based structures. [Background technology]

[0002] Currently, several types of onshore and offshore hydrocarbon processing facilities exist, such as natural gas liquefaction plants (LNG plants) on floating and gravity-based structures.

[0003] A common design is the LNG production complex, which is a floating natural gas extraction, processing, liquefaction, LNG storage, and offshore facility. Floating facilities for the extraction, storage, and offshore landing of LNG (FLNG) are used in offshore gas field development and are installed directly at the offshore gas field using anchorages and / or moorings. Such floating facilities cannot be operated in offshore locations with thick ice conditions because the drifting ice makes their reliable positioning necessary for connection to underwater pipeline frameworks impossible. Floating LNG plant applications are limited to offshore gas field development projects in ice-free waters. Furthermore, the production capacity of floating facilities is limited by their size.

[0004] An example of an LNG plant on a gravity-based structure (GBS) is the two Rectangular prism This is an onshore LNG production, storage and offloading plant (Korean Patent Publication No. 20180051852, published May 17, 2018) in which production facilities with steel caissons of different shapes, each with a smaller caisson inside a larger one, are installed on the top deck of a gravity-mounted structure. The space between the caissons is filled with solid ballast. An LNG tank is installed inside the inner caisson. This design is characterized by the following drawbacks: 1. The top support needs to be strengthened because it is on the opposite side of the internal caisson, i.e., on the installation deck, onto which the top side is attached. 2. The GBS steel body is more susceptible to corrosion and has reduced durability. 3. The GBS steel body needs to be significantly thicker to withstand ice impacts, which means greater metal consumption. 4. Solid ballast makes ballasting / de-ballasting the GBS more difficult. 5. Rectangular prism The GBS configuration has a large draft when transported to the installation site, which makes transportation through shallow water areas impossible.

[0005] There is also a floating LNG plant with LNG production facilities located on the top deck of a ship (Korean Patent Publication No. 20130009064, published on January 23, 2013). A grade separation with pipelines stands upright along the centerline of the top deck, along which equipment modules are arranged: a power generation module, a gas processing module, and a gas liquefaction module on one side, and an electrical equipment module, a dehydration module, an LNG landing module, a boil-off gas module, and a main cargo mechanism module on the other side. The bow features accommodation spaces and a turret, while the stern features a flare installation.

[0006] The design features an asymmetric modular layout, so ballasting and other design solutions are essential for vessel balancing purposes. Furthermore, floating installations cannot operate in water with icy conditions.

[0007] The complex design is closest to the one proposed, with a base slab, a top slab, an inner vertical wall and an intermediate slab, on which one or more LNG tanks are installed in a single compartment. Rectangular prism An offshore natural gas processing facility on a gravity-based structure (GBS) (International Patent Publication No. 2021 / 106151, published June 3, 2021) features a GBS with a shaped bottom, a ballast section extending along the entire GBS, and a top-side module installed on supports on the top slab. One design option features a piping module along the centerline of the top slab with processing equipment modules on its sides.

[0008] The disadvantage of this installation is that the piping modules are much longer than the other top modules, resulting in complex installation and increased distances between modules for LNG pump installation purposes, which requires a larger installation with longer piping and cabling. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Korean Patent Publication No. 20180051852 [Patent Document 2] Korean Patent Publication No. 20130009064 [Patent Document 3] International Patent Publication No. 2021 / 106151 Summary of the Invention [Problem to be solved by the invention]

[0010] The proposed invention proposes a solution to the growing problem of accumulation of facilities for LNG production in coastal waters with thick ice conditions.

[0011] The technical result is the achievement of the intended use of the invention, namely the achievement of LNG production utilizing a complex on a gravity-based structure (GBS).

[0012] The technical result is achieved by a liquefied natural gas (LNG) production complex, comprising a gravity-based structure (GBS), having a GBS top slab, a top module disposed on the GBS top slab, including at least one interconnected module along the top slab centerline and equipment modules at least a portion of which are aligned on each side of the at least one interconnected module, and a liquid storage tank is disposed inside the GBS, wherein, according to the invention, the complex comprises interconnected modules aligned along the top slab centerline, and the equipment modules are - the first row on one side of the interconnection module, i.e. At least one module of a receiving unit, a condensate stabilization unit, and an acid gas removal unit; a first row of at least one module of a mixed refrigerant compressor; - a second row on the other side of the interconnection module, i.e. Gas dehydration, mercury removal, wide distillation light hydrocarbon extraction, fractionation and liquefaction equipment modules and a second train of at least one module of a boil-off gas, a fuel gas system, and a heating medium compressor; The equipment modules are also located along the short ends of the GBS. at least one power plant module; at least one module with a main technical room and an emergency diesel generator; and at least one auxiliary system module.

[0013] Additionally, each top module has a frame with braces on which equipment is installed.

[0014] In this case, in each interconnection module, the lower main layer houses the local substations and control and measurement devices, the middle layer houses the cable overpasses, the upper layer houses the pipeline overpasses, and the open layer houses the air-cooled heat exchangers located above all the top-side module equipment.

[0015] It is advisable that the main technical room and emergency diesel generator modules are installed in the same row as the interconnection modules, and that the open layer houses the air-cooled heat exchangers.

[0016] The preferred design has a center and a protrusion, the center having a top slab. Rectangular prism and the protrusion extends along the center side around its entire periphery and has an outer vertical wall, the protrusion and the center share a base slab, and the protrusion is characterized by a GBS that is shorter in height than the center.

[0017] The GBS core has inner longitudinal and lateral walls that form a compartment, part of which the tanks are located and part of which is the ballast compartment, and the GBS projection has inner walls that are perpendicular to its outer walls and that form a compartment, part of which is the ballast compartment.

[0018] Additionally, a portion of the compartment formed by the longitudinal and lateral walls of the GBS center accommodates auxiliary equipment.

[0019] Additionally, the top modules are mounted on supports located on the top slab above the intersection of the longitudinal and lateral walls of the GBS center. [Brief explanation of the drawings]

[0020] [Figure 1] Figure 1 shows the top-down layout of the proposed industrial complex on the GBS. [Figure 2] 3 is a cross-sectional view taken along the line AA in FIG. 2. [Figure 3] FIG. 3 is a longitudinal cross-sectional view of FIG. 2 taken along the line BB. [Figure 4] FIG. 3 is a longitudinal cross-sectional view taken along CC in FIG. 2. [Figure 5] FIG. 1 shows the layout of the GBS main section. [Figure 6] FIG. 10 shows the layout of the top module supports on the GBS top slab. [Figure 7] FIG. 10 shows the layout of the top modular load-bearing structure. DETAILED DESCRIPTION OF THE INVENTION

[0021] The Liquefied Natural Gas (LNG) Production Complex on a Gravity-Based Structure (GBS) is a pre-assembled technology product that includes a set of processing, utility and auxiliary facilities for the production, storage and discharging of LNG and gas condensate.

[0022] The GBS LNG production complex will be assembled at a dedicated industrial site and then float-towed to its installation site. The GBS will be installed on a unique underbase foundation on the seabed. Gabions or other similar devices may be placed at the bottom around the GBS to prevent scouring of the seabed and the waters below it. The GBS will be installed near a dedicated pier and connected to shore by flyovers and bridges, allowing for the installation of the respective piping and cabling without the aid of underwater piping and / or long overwater flyovers, as well as easy access to the production complex and rapid evacuation of personnel. The short distance to shore allows for simpler and less expensive integration with onshore facilities, including the hydrocarbon fields that provide the raw hydrocarbons for the production complex.

[0023] The main components of the complex are the gravity-based structure (GBS) and the modular processing equipment on top.

[0024] The top side of the LNG production complex comprises modules onto which the processing and technological treatment facilities are mounted, each module being an individual, complete three-dimensional structure with processing and / or engineering facilities, piping, systems and networks intended to accomplish or support one or more LNG processing stages.

[0025] The modules are sent to their installation location on the GBS as a product with the required level of pre-assembly. Module installation on the GBS is followed by module integration in terms of connection to other modules and to the GBS equipment modules installed across the top side.

[0026] Structurally, each top module 28-41 is a three-dimensional steel framework with multiple layers of bracing inside which the equipment is installed. The modular framework with bracing (FIG. 7) generally consists of vertical columns 21, vertical braces 22, and floor beams 23 with horizontal braces.

[0027] Each module has multiple levels (decks) to facilitate equipment maintenance and personnel access. Each module is designed with at least one stairwell for personnel transfer between levels and personnel evacuation. The main levels 24 of all modules are at the same height to combine evacuation and load transport routes across the top side, thereby reducing the load on the GBS top slab 2. The other levels 42-44 of the top modules vary in height depending on their function and equipment. Transition bridges can be installed between levels of adjacent modules.

[0028] Each module has its individual purpose as part of LNG processing and its individual set of equipment. Depending on the equipment contained in the module, the module may be an equipment module or an interconnecting module.

[0029] The equipment module is Among them, there are processing modules (7 in this case) where the main LNG processing is completed, - Engineering modules (in this case three) in which the power sources and engineering systems are installed.

[0030] The interconnection modules (four in this case) contain pipe racks and cable trays, local substations and control and measurement devices, and air-cooled heat exchangers.

[0031] The processing modules 28-34 are arranged in two rows on each side along the GBS top slab 2, the interconnection modules 35-38 are positioned between the two rows along the GBS top slab 2, and the engineering modules 39-41 are concentrated at one of the short ends of the GBS (Figure 1).

[0032] This arrangement allows for a rational facility layout consistent with the LNG process sequence. The engineering module is also separated from the rest of the top side by a fire and explosion-proof wall, and there are also fire and explosion-proof walls between the processing modules, which allows for shortest distances between modules and smaller dimensions for the production complex while maintaining a high level of fire and explosion safety.

[0033] Processing module (Fig. 1 to 3) 1. The receiver, condensate stabilization, and acid gas removal module 28, which receives raw gas, controls pressure, separates liquid condensate (hydrocarbons and water), removes carbon dioxide, hydrogen sulfide, and methanol from the raw gas, and stabilizes the gas condensate, is located on the shore side of the GBS. 2. A gas dehydration and mercury removal module 29 in which mercury, water and residual methanol are removed from the raw gas. 3. Wide fraction light hydrocarbon (WFLH) extraction, fractionator module 30, in which heavy hydrocarbons are removed from the gas before it is delivered to a liquefied state. The resulting liquid hydrocarbons are stabilized and partially fractionated to obtain ethane, propane, and butane fractions. 4. Liquefaction module 31, in which the gas is cooled and depressurized to produce liquefied natural gas (LNG). Modules 29, 30 and 31 are located along the offshore side of the GBS. 5. Mixed refrigerant compressor module 32 (line A), in which three different mixed refrigerants are processed and compressed using a centrifugal compressor driven by a gas turbine. Waste heat from the gas turbine flue can be recovered to heat the heating medium. 6. Mixed refrigerant compressor module 33 (line B), in which three different mixed refrigerants are processed and compressed using a centrifugal compressor driven by a gas turbine. Waste heat from the gas turbine flue can be recovered to heat the heating medium. Modules 32 and 33 are located on the shore side of the GBS. 7. A boil-off gas, fuel gas system and heating medium compressor module 34, in which boil-off gas compression and distribution, fuel gas treatment, heating medium treatment and heating take place. Module 34 is located on the offshore side of the GBS.

[0034] Engineering System Modules 1. A power generation module 39, in which electricity is generated by a gas turbine generator. The waste heat of the gas flue can be recovered to heat the heating medium. 2. The main technical room and emergency diesel generator module 40, in which the uninterruptible power supply and control and measuring devices, as well as the air-cooled heat exchanger, are located. 3. Auxiliary system module 41, which houses the air supply system and nitrogen supply system, i.e., auxiliary systems, air compressors, air separation units, air dryers and other equipment.

[0035] Modules 39, 40 and 41 are installed along the short ends of the GBS.

[0036] The distribution of installations among modules may vary. This describes one option for filling modules with equipment.

[0037] The interconnection modules 35, 36, 37, 38, which are aligned along the GBS top slab, have a similar layout and equipment set (Fig. 4). The main layer 24 houses the local substations and the control and measurement devices 48; The intermediate layer 42 accommodates the cable crossing 47; The upper layer 43 houses the pipeline overpass 46, The open layer 44 houses the air-cooled heat exchanger 45.

[0038] However, each interconnection module 35, 36, 37, 38 has an individual equipment configuration depending on the production process taking place in the adjacent process module. For example, local substations and control and measurement devices in module 48 support the operation of equipment in the process modules on either side of each interconnection module 35, 36, 37, 38, thereby enabling optimized switchgear layout and better equipment reaction times.

[0039] Having a significant portion of the cable and pipeline overpasses 46, 47 within the interconnection modules 35, 36, 37, 38 allows for optimized piping and cable laying interconnections between modules, shorter cable and pipe runs, and extra space for equipment within the processing modules.

[0040] The air-cooled heat exchanger 45 on the open layer 44 of the interconnect modules 35, 36, 37, 38 is part of the process equipment located within the processing modules. The interconnect modules 35, 36, 37, 38 are located in the center of the top side along the GBS centerline and are higher than any of the adjacent processing modules, and the air-cooled heat exchanger 45 is located on the open layer 44, which is the highest layer of the interconnect modules 35, 36, 37, 38. Locating the air-cooled heat exchanger 45 at the highest elevation on the top side allows for the most efficient heat dissipation.

[0041] The technical room and emergency diesel generator module 40 is also located along the GBS centerline and is quite tall, which is why it also houses an air-cooled heat exchanger 45 .

[0042] The GBS is a three-dimensional structure made from reinforced concrete that serves as a storage area for the produced and processed feedstock, as well as for auxiliary substances and materials. The GBS serves as the topside foundation of the production complex and is designed to rest under its own weight on the seabed 50 of the body of water. The core 1 of the GBS is Rectangular prism and has a top slab 2 (Fig. 1).

[0043] Along the entire perimeter, on the sides of the core 1, there are GBS protrusions 3 with vertical outer walls. The GBS core 1 and the GBS protrusions 3 share the same base slab 4, with the protrusions 3 being lower than the core 1 (Figures 2 and 3).

[0044] The core 1 is divided into compartments by vertical longitudinal and transverse walls 5. Some of the compartments, e.g., compartments 6 and 15, are used for product (LNG and condensate) storage, while other compartments, e.g., compartments 7 and 20, are used for ballast water. The GBS projection 3 is divided into compartments by vertical walls 5 perpendicular to its outer walls. Compartments 8 along the periphery of the GBS are also included in the ballast system.

[0045] The top slab 2 has a reinforced concrete support 9 on which the top modules 28 to 41 are mounted.

[0046] The GBS is able to remain afloat during water transport to the site of the integrated production complex and is able to withstand ice impacts in icy conditions. The change of the GBS's status from floating to stationary at the site of installation on foundation 11 is ensured by flooding ballast compartments 7, 8 and 20.

[0047] The reinforced concrete wall 5 also acts as a load-bearing structure, transferring the load from the top side to the supporting slab 13 and under-base foundation 11, and the top support 9 is located above the intersection of the vertical longitudinal and transverse walls 5 of the GBS.

[0048] LNG storage tanks, gas condensate storage tanks, and consumables storage tanks are located inside the GBS compartment. The GBS core 1 contains several tanks, which may have different designs depending on the properties of the materials to be stored. Membrane tanks are used for LNG storage. In this case, a tank 12 with a metal membrane made of stainless steel or Invar (Fe-Ni alloy) separated from the concrete structure by an insulating layer is installed inside the concrete compartment 6 (Figures 2 and 4). The insulating layer is placed directly against the top slab 2, the middle slab 13, and the GBS walls 5, transferring the load from the tank 12 and its LNG contents to the above-mentioned boundary structures. The GBS slabs and walls thus serve as support structures for the membrane tank, and with this, they are integrated into a single structural unit. To prevent any leakage, the bottom and sides of the membrane tank 12 have a secondary barrier, which is an additional membrane installed inside the insulating layer.

[0049] The LNG will be stored in two 115,000 cbm tanks 12 located in individual compartments 6 each measuring 135x40x24 m.

[0050] Condensate may be stored in GBS concrete compartments 15 and 17, with their boundary structures acting as barriers. The 135x30x30 m stable condensate storage compartment 15 has a capacity of 75,000 cbm. The 30x8x30 m compartment 17 is used to store off-spec condensate and has a capacity of 5,000 cbm.

[0051] "Wet" storage with an underlying layer of water is used for storing condensate. In this case, the bottom layer of stored product, around 1 m thick, is considered a mixing zone that ensures the separation of water and stored product during loading operations. Compartments 15 and 17 are also slightly pressurized (from atmospheric level) using a nitrogen cushion in the top of the compartments to make compartments 15 and 17 gastight, preventing the formation of any flammable and explosive gas mixtures with hydrocarbon vapours.

[0052] Freestanding tanks located within the GBS compartment are used for wastewater, demineralized water, wash water, absorbent, butane and propane.

[0053] Tanks for the various media (liquefied gas, diesel fuel, propane, butane, ethane, water) are located within the GBS as close as possible to the relevant modules in which such media are used, making it possible to optimize the length and mass of pipelines, electrical heat tracing and insulation.

[0054] A jetty 25 for the discharge of LNG and condensate is structurally integrated with the GBS and top side. A discharge platform with fenders and loading arms and other marine and processing equipment to enable the discharge of LNG and condensate is installed on the offshore side of the GBS at a projection 3. Moorings for the berthing of tankers are installed on the offshore side of the GBS. The water area near the jetty 25 may have a seabed reinforcement 10 to protect the bottom soil from scouring by ship propellers.

[0055] The gravity-based integrated production complex is connected to the shore by two overpasses 26, on which pipelines and cableways are laid (Figures 1 and 2). The pipelines connecting the production complex to the gas fields and other facilities are equipped with cut-off valves at the onshore connections of the overpasses. There are also three evacuation bridges 27 (Figure 1), which are used for the transfer and evacuation of personnel as needed. The overpasses and bridges are made of steel and mounted on supports. The supports rest on the GBS top slab 2 at one end and on the quay wall 49 at the other end. The seabed 50 and water level 52 within the water body are shown in Figures 2 to 4.

[0056] The processing technology for the LNG production complex on the GBS is not fundamentally different from the mixed refrigerant-based processing technology used in onshore plants. Raw gas and condensate from the gas field are piped via an overpass 26 to the receiving module 28, where raw gas is received, pressure controlled, the liquid condensate (hydrocarbons and water) is separated, carbon dioxide, hydrogen sulfide, methanol, and other impurities are removed from the raw gas, and the condensate is stabilized. Processing utilizes air-cooled heat exchangers installed on the open layer of the interconnection module 35. The stabilized gas condensate is sent to storage tanks 15 and 17 housed inside the GBS, and the treated raw gas is sent to the gas dehydration and mercury removal module 29, where mercury, water, and remaining methanol are removed from the raw gas before it is sent to the wide fraction light hydrocarbon (WFLH) extraction and fractionation module 30. Processing utilizes air-cooled heat exchangers installed on the open layer of the interconnection module 35. For wide-flow light hydrocarbon (WFLH) extraction, a fractionator module 30 is used to extract heavy hydrocarbons before the processed gas is transported to a liquefied state. The resulting liquid hydrocarbons are stabilized, and a portion is fractionated to obtain ethane, propane, and butane fractions for the purpose of replenishing the mixed refrigerant components. The GBS has dedicated tanks for storing these components. The stabilized heavy hydrocarbons are sent to a gas condensate storage tank. Once processed in modules 28-30, the gas is sent to liquefaction module 31, which contains three coil-wound heat exchangers installed side-by-side. The heat exchangers are used to cool the gas, with subsequent pressure reduction and production of a liquefied fraction (LNG) and boil-off gas. The liquefied gas is sent to LNG storage tank 12 housed inside the GBS. Three mixed refrigerants (MR1, MR2, and MR3) with different compositions, consisting of mixtures of nitrogen, methane, ethane, propane, and butane, are used to cool the gas in the heat exchangers. The process utilizes air-cooled heat exchangers 45 installed on the open layers of the interconnect modules 36, 37, 38.

[0057] Mixed refrigerant processing and compression occurs in mixed refrigerant compressor modules 32 and 33. The refrigerant is air cooled downstream of the compressor in air-cooled heat exchanger 45 in interconnection modules 36, 37 and 38 through which the refrigerant circulates between liquefaction plant module 31 and mixed refrigerant compressor modules 32 and 33.

[0058] Each of the three mixed refrigerant loops has two parallel lines A and B installed in different modules, with line A installed in mixed refrigerant compressor module 32 and line B installed in mixed refrigerant compressor module 33.

[0059] Both mixed refrigerant compressor modules 32 and 33 feature the same compressor arrangement, with compressor capacity based on a 2x50% operating mode, i.e., 100% compressor backup. The MR1 and MR2 compressors in each of modules 32 and 33 are on the same shaft and base frame and are driven by the same gas turbine driver, thus reducing the number of gas turbine drivers.

[0060] Refrigerants are produced from ethane, propane and butane extracted in WFLH extraction and fractionation unit module 30 and stored in GBS tanks for refrigerant production. Nitrogen for refrigerant production is generated in auxiliary system module 41. Methane refrigeration is achieved using raw gas and boil-off gas after processing.

[0061] During offshore operation, the boil-off gas produced in the liquefaction unit module 31, the LNG storage tanks and the gas transport cargo tanks is sent to the boil-off gas, fuel gas system and heating medium compressor module 34 for boil-off gas compression and dispersion. The boil-off gas is partly used for the processing of fuel gas, which is mainly consumed by the gas turbines in the power generation station module 39 and the mixed refrigerant compressor modules 32 and 33.

[0062] The gas turbine is equipped with a waste heat recovery system to recover waste heat for use in heating the heating medium. Excess heat is rejected from the heating medium system via air-cooled heat exchangers 45 mounted on the open floor of the main technical room and emergency diesel generator module 40. The module housing the gas turbine, the waste heat recovery system, the fuel gas system, and the heating medium system are grouped together, reducing the required piping and achieving efficient heat recovery.

[0063] The mixed refrigerant compressor turbine driver and turbogenerator use a unified gas turbine, simplifying and reducing the cost of equipment operation and maintenance. [Explanation of symbols]

[0064] 1 GBS Center 2 GBS top slab 3 GBS protrusion 4 GBS base slab 5 GBS vertical wall 6 Main compartment for LNG storage tanks 7. Internal ballast compartment 8 External Ballast Compartment 9 Top support 10 Seabed reinforcement near the wharf 11 GBS Underbase Foundation 12 LNG storage tanks 13 Support slab for LNG storage tank 12 14 Vertical wall below supporting slab 13 15 Gas condensate storage tank (compartment) 16. Auxiliary and Engineering Section 17 Substandard gas condensate storage tanks (compartments) 18 Gasket 19 Space between top slab 2 and top module 10 20 Inner ballast compartment below support slab 13 21 Module support 22 module vertical brace 23 Modular floor beam (girder) 24 Top Main Deck 25 Tanker jetty 26 Interconnecting Pipe Rack to Shore 27 Evacuation Bridge 28 Receiving Unit, Condensate Stabilization Unit and Acid Gas Removal Unit Module 29 Dehydration and Mercury Removal Module 30 Wide Fraction Light Hydrocarbon (WFLH) Extraction, Fractionation and Liquefaction Unit Module 31 Liquefaction Module 32 Mixed refrigerant compressor module (Line A) 33 Mixed refrigerant compressor module (Line B) 34 Boil-off gas, fuel gas system and heating medium compressor module 35 First Interconnection Module 36 Second Interconnection Module 37 Third Interconnection Module 38 Fourth Interconnection Module 39 Power Station Module 40 Main technical room and emergency diesel generator module 41 Auxiliary System Module 42 Top side middle layer 43 Top side upper layer 44 Top side open layer 45 Air-cooled heat exchanger 46 Pipe racks on interconnection modules 47 Cable tray on interconnection module 48 Local substations and control and measurement devices on interconnection modules 49 Quay 50 Seabeds 51 Water level of water bodies

Claims

1. A liquefied natural gas (LNG) production complex comprising a gravity-based structure (GBS), having a GBS top slab, a top module disposed on the GBS top slab, at least one interconnected module along a centerline of the GBS top slab, and equipment modules at least a portion of which are aligned on each side of the at least one interconnected module, wherein a liquid storage tank is disposed inside the GBS; 1. A liquefied natural gas (LNG) production complex comprising: a GBS having a central portion and a protruding portion, the central portion being a rectangular parallelepiped having a GBS top slab; the protruding portion extending along the central portion around its entire periphery and having an outer vertical wall; the protruding portion and the central portion sharing a base slab; the protruding portion being shorter in height than the central portion; the central portion having inner longitudinal and lateral walls forming a compartment, part of which houses the liquid storage tank, part of which is a ballast compartment; and the protruding portion having an inner wall perpendicular to its outer wall and forming a compartment, part of which is the ballast compartment.

2. The LNG production complex comprises interconnected modules arranged in a row along the centerline of the GBS top slab, and the equipment modules are: A first row on one side of the interconnection module, i.e. At least one module of a receiving unit, a condensate stabilization unit, and an acid gas removal unit; a first row of at least one module of a mixed refrigerant compressor; A second row on the other side of the interconnection module, i.e. Gas dehydration, mercury removal, wide distillation light hydrocarbon extraction, fractionation and liquefaction equipment and a second train of at least one module of a boil-off gas, a fuel gas system, and a heating medium compressor; The equipment modules also include: at least one power plant module; at least one module with a main technical room and an emergency diesel generator; and at least one auxiliary system module with air and nitrogen supply systems.

3. 2. The complex of claim 1, wherein each top module has a frame with braces and on whose layers the equipment is installed.

4. 4. The complex of claim 3, characterized in that in each interconnected module, the lower main layer houses local substations and control and measurement devices, the middle layer houses cable crossings, the upper layer houses pipeline crossings, and the open layer houses air-cooled heat exchangers located above all top-side module equipment.

5. 5. The complex according to claim 4, characterized in that the main technical room and emergency diesel generator modules are installed in the same row as the interconnection modules, and that the open layer houses an air-cooled heat exchanger.

6. 2. The complex according to claim 1, characterized in that the top modules are mounted on supports placed on the GBS top slab above the intersection of the longitudinal and transverse walls of the central section.

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