Liquefied natural gas production facilities on gravity-based structures

Abstract

The present invention relates to a production facility and can be used for the development of an integrated onshore and offshore liquefied natural gas (LNG) production complex on gravity-based structures. The liquefied natural gas (LNG) production complex comprises at least two gravity-based structures (GBS) 4-6, each of which houses a natural gas liquefaction production line 1-3 using a mixed refrigerant, the natural gas liquefaction production line 1-3 including a feed gas receiving and processing facility, a gas condensate stabilization facility, a gas dehydration and mercury removal facility, a wide-fraction light hydrocarbon (WFLH) extraction facility, a refrigerant treatment and compression system, and a liquefaction facility, at least one production line 1 (2, 3) on the GBS 4 (5, 6) includes a fractional distillation facility for producing mixed refrigerant components from NGLs, and at least one respective GBS 4 (5, 6) has at least one storage tank for each mixed refrigerant component. Each GBS 4 (5, 6) has at least one LNG storage tank. At least one GBS 4 (5, 6) has at least one Stable Gas Condensate (SGC) storage tank. At least one GBS has an extension 7 (8) for shipping LNG and SGC to gas carriers. At least one of the tanks for each mixed refrigerant component has a pipeline connection to the refrigerant treatment and compression system of each production line to form a single mixed refrigerant component replenishment system. At least one SGC storage tank has a pipeline connection to the condensate stabilization facility of each production line to form a single SGC storage and shipping system. The LNG storage tank has a pipeline interconnection to form a single LNG storage and shipping system. The present invention allows for the avoidance of excessive equipment duplication by developing a shared technology system for the entire complex.

Description

【Technical Field】 【0001】 The present invention relates to production facilities and can be used for the development of coastal and offshore integrated liquefied natural gas (LNG) production complexes on gravity-based structures. 【Background Art】 【0002】 There are several types of coastal and offshore hydrocarbon processing plants, such as natural gas liquefaction plants (LNG plants) on floating and gravity-based foundation structures. 【0003】 A common design is an LNG production complex, which includes floating natural gas production, processing, liquefaction, LNG storage, and offloading facilities. Floating facilities for the production, storage, and offloading of LNG (FLNG) are used for offshore gas field development and are installed directly in the offshore area using anchoring and / or mooring. Such floating facilities are not operated at offshore locations with severe ice conditions because reliable positioning of the floating facilities required to connect to valves on underwater pipes is impossible due to drifting ice, and thus, the application of floating LNG plants is limited to the development of offshore areas in ice-free oceans. Moreover, the production capacity of floating facilities is limited by the size of the floating facilities, and the floating facilities can accommodate only a single production line, and a complete set of main and auxiliary devices is required to support line operation, while at the same time, limiting important device sparing options. 【0004】 One example of an LNG plant on a gravity-based structure (GBS) is a coastal LNG production, storage, and shipping plant (US 2016 / 0231050 A1, published: 2016 / 08 / 11) in which the liquefaction unit is installed on the top deck of the gravity-based structure, and the plant capacity can be expanded by installing additional equipment in the existing area of ​​the GBS top slab and / or by using additional process equipment mounted on dedicated foundation structures stationary on the seabed or shore near the GBS that house the majority of the process equipment. This design has the following drawbacks: 1. A larger GBS for accommodating additional equipment. 2. Equipment belonging to the same production line is dispersed across several locations, which means longer pipe and cable runs and more complex plant operations. 3. Equipment duplication in the case of capacity expansion. 4. The equipment on individual production lines cannot be used for the purpose of spare parts for the production complex as a whole. 【0005】 The closest proposed complex design features an LNG plant on three gravity-based structures (GBS), each housing an individual production line (Arctic LNG2 Project. Environmental, Social and Health Impact Assessment. Non-Technical Overview. Ramboll). Created by CIS. August 2020, pages 10-12. (http: / / arcticspg.ru / %D0%A0%D0%B5%D0%B7%D1%8E%D0%BC%D0%B5%20%D0%BD%D0%B5%D1%82%D0%B5%D1%85%D0%BD%D0%B8%D1%87%D0%B5%D1%81%D0%BA%D0%BE%D0%B3%D0%BE%20%D1%85%D0%B0%D1%80%D0%B0%D0%BA%D1%82%D0%B5%D1%80%D0%B0 / Arctic%20LNG%202%20NTS%20v3_final%20report_RUS_clean.pdf). The LNG plant comprises three gravity-based structures (GBS), each housing a natural gas liquefaction line utilizing a mixed refrigerant. The natural gas liquefaction line includes a gas condensate stabilization unit, a mercury removal unit, an acid gas removal and dehydration unit, and a wide-fraction system. Light The GBS includes a wide fraction of light hydrocarbons (WFLH) extraction facility, a liquefaction facility, and a fractional distillation facility for producing mixed refrigerant components from the WFLH, and each GBS has at least one LNG storage tank and at least one stable gas condensate (SGC) storage tank, and each GBS also has at least one tank for each mixed refrigerant component, as well as LNG and SGC discharge outlets. 【0006】 The drawbacks of this facility are that the process equipment is tripled across three production lines, and that the individual line equipment cannot be used as a whole for spare parts of the production complex equipment. [Prior art documents] [Patent Documents] 【0007】 [Patent Document 1] US 2016 / 0231050 A1 [Non-patent literature] 【0008】 [Non-Patent Document 1] Arctic LNG2 Project. Environmental, Social, and Health Impact Assessment. Non-Technical Summary. Prepared by Ramboll CIS. August 2020, pp. 10-12. http: / / arcticspg.ru / %D0%A0%D0%B5%D0%B7%D1%8E%D0%BC%D0%B5%20%D0%BD%D0%B5%D1%82%D0%B5%D1%85%D0%BD%D0%B8%D1%87%D0%B5%D1%81%D0%BA%D0%BE%D0%B3%D0%BE%20%D1%85%D0%B0%D1%80%D0%B0%D0%BA%D1%82%D0%B5%D1%80%D0%B0 / Arctic%20LNG%202%20NTS%20v3_final%20report_RUS_clean.pdf [Overview of the project] [Problems that the invention aims to solve] 【0009】 The proposed invention provides a solution to the technical problem of equipment duplication in an LNG production complex comprising two or more production lines, each housed on a dedicated GBS. [Means for solving the problem] 【0010】 The technological achievements of this invention enable the avoidance of excessive equipment duplication by developing a shared technology system for the entire complex. Furthermore, several design options for the complex allow for necessary spare parts for critical systems by using equipment on one GBS to maintain the operation of production lines housed on other GBSs. 【0011】 The technological achievement is a liquefied natural gas (LNG) production complex comprising at least two GBSs, each of which houses a natural gas liquefaction production line using a mixed refrigerant, and the natural gas liquefaction production line includes raw gas receiving and processing equipment, gas condensate stabilization equipment, gas dehydration and mercury removal equipment, and wide fraction Light The facility is provided as a liquefied natural gas (LNG) production complex, comprising a hydrocarbon (WFLH) extraction unit, a refrigerant processing and compression system, and a liquefaction unit, wherein at least one GBS production line includes a fractional distillation unit for producing mixed refrigerant components from WFLH, and at least one GBS has at least one storage tank for each mixed refrigerant component. Each GBS has at least one LNG storage tank. At least one GBS has at least one stable gas condensate (SGC) storage tank. At least one GBS has an overhang for shipping LNG and SGC to a tanker. 【0012】 According to the present invention, at least one of the tanks for each mixed refrigerant component has pipeline connections to the refrigerant processing and compression systems of each production line to form a single mixed refrigerant component replenishment system, at least one SGC storage tank has pipeline connections to the condensate stabilization equipment of all production lines to form a single SGC storage and shipping system, and the LNG storage tanks have pipeline interconnections to form a single LNG storage and shipping system. 【0013】 The following design options are available for the mixed-use facility. 【0014】 The complex may include two GBSs, with fractional distillation equipment installed on one or each of the two production lines, and at least one of the tanks for each mixed refrigerant component installed in one or each of the two GBSs. 【0015】 The complex facility may include at least three GBSs, the fractional distillation equipment is installed on at least two production lines, and at least one of each of the tanks for each mixed refrigerant component is installed in at least two respective GBSs. 【0016】 In the case of a complex facility with two GBSs, at least one of the SGC storage tanks is installed in one or each of the two GBSs. 【0017】 In the case of a complex facility with three or more GBSs, at least one SGC storage tank is installed in at least two GBSs. 【0018】 Furthermore, in the case of a complex facility with three or more GBSs, extensions for shipping LNG and SGC are available on at least two GBSs. 【0019】 Each production line may include a nitrogen system including air separation equipment, a nitrogen storage tank, and a nitrogen vaporizer, one of the production lines also has backup air separation equipment, and the nitrogen systems have pipeline interconnections for forming a single nitrogen supply system. 【0020】 Each production line may include air compressor equipment, two of the production lines have backup air compressor equipment, and the air compressor equipment has pipeline interconnections for forming a single compressed air supply system. 【0021】 Each production line may include air dryer equipment, two of the production lines have backup air dryer equipment, and the air dryer equipment has pipeline interconnections for forming a single dry air system. 【0022】 Each GBS has a power plant, all power plants have cable interconnections to form a single power system, each power plant has a gas turbine generator (GTG), and it is desirable that two of the power plants each have a backup GTG. [Brief explanation of the drawing] 【0023】 [Figure 1] This diagram shows the structure of the production complex on GBS. [Figure 2] This diagram shows the mechanism of the GBS production line as viewed from above. [Figure 3] This is a cross-sectional view AA of Figure 1. [Figure 4] This is a diagram showing the longitudinal section BB of Figure 1. [Figure 5] This diagram shows the mechanism of the SGC storage and shipping system. [Figure 6] This diagram shows the mechanism of the WFLH fractional distillation and mixed refrigerant component replenishment system. [Figure 7] This diagram shows the mechanism of the LNG storage and shipping system. [Figure 8] This is a diagram illustrating the mechanism of the nitrogen system. [Figure 9] This diagram shows the mechanism of the power supply system. [Figure 10] This is a diagram showing the mechanism of an air compressor system. [Figure 11] This is a diagram showing the mechanism of an air drying system. [Modes for carrying out the invention] 【0024】 A liquefied natural gas (LNG) production complex on a gravity-based structure (GBS) is a combination of processes, engineering, and auxiliary equipment for the production, storage, and shipment of LNG and SGC. The complex may comprise two or more production lines on the gravity-based structure (GBS). 【0025】 The drawing shows an exemplary complex comprising three production lines 1, 2, and 3, each located on a dedicated GBS 4, 5, and 6 (Figure 1). Each production line 1(2, 3), along with its respective GBS 4(5, 6), is a prefabricated product manufactured in a specialized company and then towed while floating to the installation site of each production line 1(2, 3). Production line 1(2) on GBS 4(5) may have an overhang 7(8) for shipping products to tankers (Figure 2). On site, GBS 4-6 are installed on a dedicated underbase foundation 22 on the seabed near a dedicated dock area (Figures 3, 4). Production lines 1-3 on GBS 4-6 are interconnected by piping and cable laying on elevated bridges 9, enabling the integration of production lines 1-3 into a single production complex. Each GBS is also connected to the shore by viaducts and bridges, enabling the installation of respective piping and cable layings to the shore without the need for underwater pipelines and / or long overwater viaducts, as well as easy access to the production complex and rapid personnel evacuation. The short distance to the shore allows for simpler and less expensive integration with onshore facilities, including hydrocarbon fields, from which raw materials are supplied to the production complex. 【0026】 High-pressure flares 10 and general economy flares 11 are installed on the shore near production lines 1-3, so that they can be shared by the entire complex (Figure 1). 【0027】 Each production line 1-3 is located on the top side (modularized process equipment) of GBS4-6 (Figures 2, 3, and 4). The main process equipment where the gas processing and liquefaction process sequences are completed includes an inlet facility 28, which includes raw gas receiving and processing equipment and gas condensate stabilization equipment; a gas dehydration unit 29 and a mercury removal unit 30; a WFLH extraction unit 31 and a fractional distillation unit 32; a gas liquefaction unit 33; mixed refrigerant compressor units 34 and 35; a boil-off gas compressor unit 36; a fuel gas unit 37; and a heat transfer fluid system unit 38 (Figure 2). 【0028】 The main process equipment on both sides of the GBS, as well as the power plant 43, emergency diesel generator 44, nitrogen system equipment 45, air compressor equipment 46, and air dryer equipment 47, have pipelines, cable trays, and bridge connections via interconnection modules 39-42. 【0029】 GBS4-6 are three-dimensional structures made of reinforced concrete, and their function is to serve as storage for extracted and processed raw material gases, as well as auxiliary substances and materials. GBS4-6 form the foundation for the top side (production lines 1-3) and are designed to be installed on the seabed of the body of water with the help of the weight of GBS4-6 themselves. The central part 12 of the GBS is a right-angle prism with a top slab 13 (Figures 3 and 4). 【0030】 Along its outer perimeter, the GBS has a projecting portion 14 with a vertical outer wall on the side of the central portion 12. The GBS central portion 12 and the projecting portion 14 share a foundation slab 15, and the projecting portion 14 is lower than the central portion 12. 【0031】 The central GBS section 12 is divided into compartments by vertical longitudinal and transverse walls 16. Some of these compartments, for example, compartments 17 and 18, are used for product storage (LNG and SGC), while other compartments, for example, compartments 19, 20, and 21, are used for ballast water. The GBS projection section 14 is divided into compartments 20 along the outer perimeter of the GBS by vertical walls perpendicular to the outer walls of the GBS projection section 14, and these compartments 20 are also included in the ballast system. 【0032】 The GBS top slab 13 has a reinforced concrete support 24 on which the top module is installed. 【0033】 GBS4-6 can remain afloat during water transport to the integrated production complex site and can withstand the effects of ice in icy conditions. The transition of GBS4-6 from floating to stationary at the installation site on foundation 22 is ensured by filling ballast compartments 19, 20, and 21 with water. 【0034】 To prevent abrasion of the bottom beneath GBS4-6 and the bottom of the water body, seabed reinforcement materials 23, such as gabions or other similar devices, may be placed on the waterbed around GBS4-6 (Figure 3). 【0035】 The technical processes of the GBS LNG production complex do not differ fundamentally from the mixed refrigerant-based process technologies used in onshore plants. Each process production line for natural gas liquefaction using mixed refrigerants includes an inlet facility 28 which includes equipment for receiving and processing the raw material gas and for stabilizing the gas condensate. The raw material gas and condensate from the field are piped to the inlet facility 28 via elevated bridges 9, where raw material gas receiving, pressure control, separation of liquid condensate (hydrocarbons and water), removal of carbon dioxide, hydrogen sulfide, methanol, and other impurities from the raw material gas, and gas condensate stabilization take place. 【0036】 Stabilized gas condensate (SGC) is present in approximately 75,000 m³. 3 The SGC is sent to a storage tank with a capacity of (Figure 3). At least one concrete compartment 18 with dimensions of 135 × 30 × 30 m is used as the SGC storage tank, and the outer structure of the SGC storage tank acts as a protective barrier. A “wet” storage facility with a foundation water layer is used for SGC storage. In this case, the bottom layer of the stored product, which is about 1 m thick, is considered a mixing zone to ensure the separation of water and the stored product during loading operations. Compartment 18 is slightly pressurized (from atmospheric pressure level) using a nitrogen cushion in the upper part of the compartment to prevent air from entering the compartment and to prevent the formation of flammable and explosive gas mixtures with hydrocarbon vapors. 【0037】 The SGC storage and shipping system (Figure 5) is common to the entire production complex, and condensates can be pumped between at least two production lines via onshore pipelines, allowing each GBS to be free of SGC storage tanks. If the complex comprises two GBSs, the SGC storage tanks can be located in either one of the two GBSs or in both GBSs. If the complex comprises at least three GBSs, the SGC storage tanks are located in at least two GBSs, in this example only GBS4 and 5, where SGCs are also sent for storage from a third production line 3, which does not have a condensate storage tank. 【0038】 The treated raw material gas is continuously sent to the dehydration unit 29 and the mercury removal unit 30, where mercury, water, and residual methanol are removed from the raw material gas before it is sent to the wide-fraction photohydrocarbon (WFLH) extraction unit 31. In the WFLH extraction unit 31, ethane, propane, butane, and NGL components are extracted from the treated gas before it is sent for liquefaction. 【0039】 At least one production line has a WFLH fractional distillation unit 32. The ethane, propane, and butane produced in the unit are used for the purpose of replenishing the mixed refrigerant components. The mixed refrigerant component replenishment system 48 is common to the entire complex. The refrigerant components can be pumped between production lines through onshore pipelines. If the complex has two GBS and two production lines, the fractional distillation unit may be placed on one or both of the production lines. If the complex consists of at least three production lines, it is sufficient to place the fractional distillation unit on at least two of the at least three production lines. In this example, the fractional distillation unit is installed on the first and second production lines 1 and 2 (Figure 6), where hydrocarbons extracted from the gas are fractionally distilled to produce ethane, propane, and butane portions. The remaining stabilized heavy hydrocarbons are sent to an SGC storage tank, i.e., compartment 18. 【0040】 To store the mixed refrigerant components in at least one GBS, separate tanks 27 are provided in at least two GBS in the case of at least three GBS, in this example in the first and second GBS 4 and 5, and at least one tank for each mixed refrigerant component is used for replenishing the mixed refrigerant components in all three production lines 1-3, including production line 3 which does not have fractional distillation equipment and mixed refrigerant component storage tanks (Figure 6). WFLH extracted in the third GBS 6 is returned to the treated gas flow to the liquefaction equipment or sent to a WFLH fractional distillation unit installed in GBS 4 or 5. If the complex has two GBS, the tanks for each mixed refrigerant component may be located in one or two GBS that have fractional distillation equipment. In the case of at least three GBS, having fractional distillation equipment and tanks for each mixed refrigerant component in at least two production lines (1 and 2) makes it possible to ensure the duplication of this crucial equipment. Each tank 27 for each mixed refrigerant component has pipeline connections to the refrigerant processing and compression systems of each production line to form a single mixed refrigerant component replenishment system 48. 【0041】 The processed gas is sent to a liquefaction facility 33 where three coil-wound heat exchangers are successively installed and used to cool the gas, after which throttling and production of the liquefied portion (LNG) and boil-off gas takes place. Three mixed refrigerants with different compositions, which are mixtures of nitrogen, methane, ethane, propane, and butane, are used for cooling the gas in the heat exchangers. The liquefied gas is sent to LNG storage tanks 25 housed within each GBS 4-6. The LNG storage tanks 25 have pipeline interconnections to form a single LNG storage and shipping system. The LNG storage and shipping system (Figures 7, 10) is common to the entire production complex, and LNG can be pumped between tanks 25 in various GBSs via onshore pipelines, allowing for maximum use of the total tank capacity. 【0042】 Each of the GBS4-6 has a length of 115,000 m 3 It accommodates at least one, preferably two, tanks 25 for LNG storage, each with a capacity of approximately 690,000 m³. 3 The membrane tank is used for LNG storage. In this case, a tank 25 made of a steel membrane made of stainless steel or Invar (Fe-Ni alloy), separated from the concrete structure by an insulating layer, is installed within a concrete compartment 17 (Figures 3 and 4). The insulating layer is placed directly on the top slab 13, the intermediate slab 26, and the GBS wall 16, and transmits the load from the tank 25 and its LNG contents to the aforementioned enclosure structure. The GBS slab and wall thus act as a support structure for the membrane tank 25, and the membrane tank 25 is integrated into a single structure with the support structure. To prevent leakage, the bottom and sides of the membrane tank 25 have a secondary barrier, which is an additional membrane installed within the insulating layer. 【0043】 The tanks for storing ethane, a component of the mixed refrigerant, have a similar membrane structure but a smaller capacity. GBS4 and GBS5 each have a capacity of approximately 1,200 m³. 3It has one ethane tank with a capacity of (Figures 3 and 6). 【0044】 The freestanding tanks installed within the GBS4 and GBS5 compartments are used for other mixed refrigerant components, namely butane and propane. The two GBS4 and GBS5 compartments are each 280 m³ each. 3 One tank for storing butane with a capacity of 280m 3 It has one tank for propane storage with a capacity of (Figures 3 and 6). 【0045】 Tanks 27 for each mixed refrigerant component are located within the GBS as close as possible to the relevant process equipment where these components are used, allowing for optimization of pipeline length and mass, electrical heat tracing, and insulation. 【0046】 The refrigerant is processed and compressed in mixed refrigerant compressor equipment 34 and 35 (Figure 2). Each of the three mixed refrigerant loops has two parallel strings A and B in the form of two separate equipment, each with 50% of its total capacity. This allows the production complex to operate at 50% capacity even if half of the compressor equipment is shut down. 【0047】 Each unit has two compressors on one shaft and one frame. Each such pair of compressors is driven by one gas turbine drive unit, which reduces the number of gas turbine drives required. All drives have the same capacity and are fully integrated, which simplifies the operation and repair of all drives. 【0048】 Ethane, propane, and butane extracted from WFLH in fractional distillation unit 32 and stored in tank 27 for replenishment in GBS1 and 2 are used to produce refrigerants. Methane replenishment is carried out using treated raw material gas and boil-off gas. Nitrogen for refrigerant replenishment is produced in an integrated nitrogen system unit 45, which includes an air separation unit 49 with an air purification and dehydration system, a liquid nitrogen storage tank 50, and a liquid nitrogen vaporizer 51 (Figure 8). Production line 1 houses the integrated air separation unit 49 in a 2 x 100% configuration (one unit is operational and one is on standby), while production lines 2 and 3 each have an air separation unit 49 in a 1 x 100% configuration. Nitrogen production redundancy for the entire production complex is ensured by the capacity to pump nitrogen between production lines, including production line 1. In addition to replenishing mixed refrigerants, nitrogen is used to create an inert medium and gas cushion, for purging, and for compressor dry gas sealing, and as a backup source for purge gas. 【0049】 The boil-off gas generated in the liquefaction equipment 33, LNG storage tanks 25, and in the cargo tanks of the gas carrier during shipment is sent to the boil-off gas compressor equipment 36 for boil-off gas compression and supply. Some of the boil-off gas is used for processing in the fuel gas equipment 37, while the rest is consumed by gas turbines and mixed refrigerant compressor equipment in power plants. 【0050】 The power supply system is common to the entire production complex (Figure 9). The system is based on gas turbine power plants 43 in each production line 1 to 3. Each power plant 43 in production lines 1 and 2 has three gas turbine generators (GTGs) 52, including two in operation and one in standby, while production line 3 has two GTGs 52. The turbine drive units for the GTGs 52 and mixed refrigerant compressors of the power plants use integrated gas turbines, which makes it easier and cheaper to operate and maintain the equipment. The gas turbines are equipped with facilities for recovering waste heat so that it is used to heat the heating medium in the heating medium system equipment 38. 【0051】 The emergency diesel generator 44 serves as a standby power source. The power plant 43, spanning three production lines, is incorporated into a single power system with the help of cables extending through the elevated bridge 9, thus enabling an N+2 power generation sparering configuration. 【0052】 A similar sparering principle is used for air compressors and air dryers, where air supply systems across three production lines are interconnected for this purpose. 【0053】 On production lines 1 and 2, the air compressor equipment 46 is installed in a 3 x 50% configuration (two are operational and one is on standby), while on production line 3, the air compressor equipment 46 is installed in a 2 x 50% configuration (Figure 10). Spareling of the air compressor equipment on production line 3 is ensured by the backup capacity of production lines 1 and 2. 【0054】 Air dryer equipment 47 is installed on each production line, two of which also have backup air dryer equipment. On production lines 1 and 2, these units are installed in a 3 x 50% configuration (two are operational and one is on standby), and on production line 3, air dryer equipment is installed in a 2 x 50% configuration (Figure 11). Spareling of the air dryer equipment 47 on production line 3 is ensured by the backup air dryer equipment 47 on production lines 1 and 2. Dry air is used to increase the pressure in the gas turbine engine and to provide an air barrier to the coupling of the gas turbine drive unit of the mixed refrigerant compressor. 【0055】 LNG is shipped to tankers for transporting liquefied gas via extensions 7 and 8 located only on production lines 1 and 2 and GBS 4 and 5 (Figure 1). The same extensions 7 and 8 are used for SGC shipments. Products from production line 3 are shipped via the LNG and SGC storage and shipment system to the extensions of production lines 1 and 2. 【0056】 The loading extensions 7 and 8 are structurally integrated with the GBS 4 and 5 and the top side. A technical platform with fenders and loading arms, as well as other offshore and processing equipment enabling LNG and SGC shipments, are installed on the berthing side projection 14 of the GBS. Mooring equipment for tanker berthing is installed on the berthing side of the GBS. The water area near the extensions 7 and 8 may have seabed reinforcement 23 to protect the bottom soil from abrasion by ship propellers (Figure 3). 【0057】 Production lines 1-3 are interconnected by cables and pipelines extending over elevated bridge 9 and the dock area. The same elevated bridge 9 is used to connect the production complex to the field and other onshore facilities. [Explanation of symbols] 【0058】 1. Production line (GBS top side) 2. Production line (GBS top side) 3. Production line (GBS top side) 4 GBS 5 GB 6 GBS 7. Overhang for tankers 8. Overhang for tankers 9. Interconnecting viaducts 10 High-pressure flares 11 General Economy Objects 12 GBS central part 13. Top slab of the central part of the GBS 14 GBS protrusion 15 GBS foundation slab 16 GBS Vertical Wall 17 LNG storage compartments 18 SGC Storage Areas 19 Internal ballast compartment 20 External ballast section 21. Internal ballast compartment beneath the intermediate support slab of the LNG storage tank. 22 GBS Underbase Foundation 23 Seabed reinforcement materials 24 Top support 25 LNG storage tanks 26 Support slabs for LNG storage tanks 27. Storage tank for mixed refrigerant components 28 Entrance Facilities and Equipment 29. Gas dehydration equipment 30 Mercury removal equipment 31 WFLH extraction equipment 32 Fractional distillation equipment 33 Gas liquefaction equipment 34. Mixed refrigerant compressor equipment (Line A) 35. Mixed refrigerant compressor equipment (Line B) 36. Boil-off gas compressor equipment 37 Fuel gas equipment 38 Heating medium system equipment 39. First interconnection module 40. Second interconnection module 41 Third interconnection module 42. Fourth interconnection module 43 Power plants 44 Emergency diesel generator 45 Nitrogen System Equipment 46 Air Compressor Equipment 47. Air drying equipment 48. Mixed refrigerant component replenishment system 49 Air separation equipment 50 Nitrogen Storage Tanks 51 Nitrogen vaporizer 52 Gas Turbine Generators 53. Wharf area 54 Undersea 55 Water surface

Claims

[Claim 1] A liquefied natural gas (LNG) production complex comprising at least two gravity-based structures (GBS), each of which houses a natural gas liquefaction production line using a mixed refrigerant, the natural gas liquefaction production line including a raw gas receiving and processing unit, a gas condensate stabilization unit, a gas dehydration and mercury removal unit, a wide-fraction light hydrocarbon (WFLH) extraction unit, a refrigerant treatment and compression system, and a liquefaction unit. At least one GBS production line includes fractional distillation equipment for producing mixed refrigerant components from WFLH, Each of the GBSs has at least one storage tank for each mixed refrigerant component, Each GBS has at least one LNG storage tank, At least one GBS has at least one stable gas condensate (SGC) storage tank, In a combined facility, at least one GBS has extensions for LNG and SGC shipments, At least one of the tanks for each mixed refrigerant component has a pipeline connection to the refrigerant processing and compression system of each production line to form a single mixed refrigerant component replenishment system. At least one SGC storage tank has pipeline connections to condensate stabilization equipment for each production line to form a single SGC storage and shipping system. The LNG storage tanks have pipeline interconnections to form a single LNG storage and shipping system. Characterized by, A multi-purpose complex. [Claim 2] The composite facility according to claim 1, characterized in that the composite facility comprises two GBS, the fractional distillation equipment is installed on one or each of the production lines, and at least one tank for each mixed refrigerant component is installed in one or each of the two GBS. [Claim 3] The composite facility according to claim 1, characterized in that the composite facility comprises at least three GBS, the fractional distillation equipment is installed on at least two production lines, and at least one of the tanks for each mixed refrigerant component is installed in at least two of the respective GBS. [Claim 4] The composite facility according to claim 1, characterized in that the composite facility comprises two GBSs, and at least one SGC storage tank is installed in one or each of the two GBSs. [Claim 5] The composite facility according to claim 1, characterized in that the composite facility comprises at least three GBS, and at least one SGC storage tank is installed in at least two GBS. [Claim 6] The composite facility according to claim 1, characterized in that the composite facility comprises at least three GBSs, and the LNG and SGC shipping extensions are available on at least two GBSs. [Claim 7] The composite facility according to claim 1, characterized in that each production line is equipped with a nitrogen system including an air separation unit, a nitrogen storage tank, and a nitrogen vaporizer, one of the production lines also has a backup air separation unit, and the nitrogen system has pipeline interconnections to form a single nitrogen supply system. [Claim 8] The composite facility according to claim 1, characterized in that each production line is equipped with an air compressor, two of the production lines have backup air compressors, and the air compressors have pipeline interconnections to form a single compressed air supply system. [Claim 9] The composite facility according to claim 1, characterized in that each production line is equipped with an air dryer, two of the production lines have backup air dryer equipment, and the air dryer equipment has pipeline interconnections to form a single dry air system. [Claim 10] The complex facility according to claim 1, characterized in that each GBS houses a power plant, all of the power plants have cable interconnections to form a single power system, each power plant has a gas turbine generator (GTG), and two of the power plants each have a backup GTG.

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