Liquefied natural gas production facility on gravity structure

Abstract

A liquefied natural gas (LNG) production facility includes a gravity structure (GBS) having a production line for liquefied natural gas. The GBS comprises: a storage tank for each mixed refrigerant component, where the production line of the GBS comprises a fractionation device to generate the mixed refrigerant component from the wide fraction light hydrocarbon; a stable gas condensate (SGC) storage tank; and the wharf is used for unloading the LNG and the SGC to the transport ship. And each GBS comprises an LNG storage tank. Each storage tank for each mixed refrigerant component from each GBS has a piping connection to the refrigerant processing and compression system of each production line, thereby forming a single mixed refrigerant component supplementation system. The SGC storage tank has a piping connection to the gas condensate stabilization device of each production line, thereby forming a single SGC storage and unloading system. The LNG storage tanks have piping interconnects to form a single LNG storage and offload system. According to the invention, a technical system for shared use is developed for the whole facility, so that excessive equipment repetition is avoided.

Description

Technical Field

[0001] The present invention relates to production facilities that can be used to develop integrated onshore and offshore liquefied natural gas (LNG) production complexes on gravity-fed structures. Background Art

[0002] There are various types of onshore and offshore hydrocarbon processing plants, such as natural gas liquefaction plants (LNG plants) on floating and gravity-based substructures.

[0003] One common design is the LNG production complex, i.e. a floating natural gas production, processing, liquefaction, LNG storage and offloading unit. Floating units for the production, storage and offloading of LNG (FLNG) are used in offshore gas field developments and are installed directly on the offshore gas field by anchoring and / or mooring. Such floating units cannot operate in offshore areas with heavy ice because they cannot reliably locate valves connected to underwater pipelines due to floating ice, so the application of floating LNG plants is limited to offshore gas field developments in ice-free waters. In addition, the production capacity of floating units is limited by their size. They can only accommodate one production line, requiring a full set of main and auxiliary equipment to support the production line operation, while limiting the backup options for key equipment.

[0004] An example of an LNG plant on a gravity structure (GBS) is a nearshore LNG production, storage and unloading plant (US2016 / 0231050A1, publication date: 2016 / 08 / 11), whose liquefaction equipment is mounted on the top plate of the gravity structure, and the plant capacity can be expanded by installing additional equipment in the existing area of ​​the GBS top plate and / or using additional processing equipment installed on its dedicated base structure, which is located on the seabed or coast near the GBS and can accommodate most of the processing equipment. This design has the following disadvantages.

[0005] 1. Large size GBS to accommodate additional equipment.

[0006] 2. Equipment belonging to the same production line is distributed in multiple locations, which means longer pipe and cable runs and more complex factory operations.

[0007] 3. Equipment duplication when expanding capacity.

[0008] 4. Equipment of a single production line cannot be used for backup purposes of the entire production complex.

[0009] The complex design that is closest to the proposed solution is to build an LNG plant on three gravity-fed structures (GBS), each housing a separate production line (Arctic LNG 2 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 The LNG plant includes three gravity structures (GBS), each of which contains a natural gas liquefaction pipeline that relies on mixed refrigerant, including a gas condensate stabilization unit, a mercury removal unit, an acid gas removal and dehydration unit, a wide-fraction light hydrocarbon (WFLH) extraction unit, and a liquefaction unit and a fractionation unit for generating mixed refrigerant components from WFLH. Each GBS has at least one LNG storage tank and at least one stable gas condensate (SGC) storage tank. Each GBS also has at least one mixed refrigerant component storage tank and an LNG and SGC unloading terminal.

[0010] The disadvantage of this facility is that there are three times as many processing equipment on the three production lines, and it is not possible to use the equipment of the individual production lines to save resources on the equipment of the entire production complex. Summary of the invention

[0011] The proposed invention provides a solution to the technical problem of duplication of equipment in an LNG production complex consisting of two or more production lines, each of which is installed on a dedicated GBS.

[0012] The technical effect achieved by the present invention is to avoid duplication of too much equipment by developing a shared technical system for the entire complex. Certain design options of the complex also allow the use of equipment on a GBS to maintain the operation of production lines on other GBSs, thereby achieving necessary savings in key systems.

[0013] The technical effect is a liquefied natural gas (LNG) production complex, including at least two GBSs, each GBS is equipped with a natural gas liquefaction production line using a mixed refrigerant, including a raw gas receiving and processing device, a gas condensate stabilization device, a gas dehydration and mercury removal device, a wide-fraction light hydrocarbon (WFLH) extraction device, a refrigerant processing and compression system, and a liquefaction device, wherein at least one GBS production line includes a fractionation device to generate a mixed refrigerant component from the WFLH, and at least one corresponding 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 a terminal for unloading LNG and SGC into tankers.

[0014] According to the present invention, at least one of each storage tank for each mixed refrigerant component has a pipeline connection to the refrigerant handling and compression system of each production line, thereby forming a single mixed refrigerant component replenishment system, at least one SGC storage tank has a pipeline connection to the condensate stabilization devices of all production lines, thereby forming a single SGC storage and unloading system, and the LNG storage tanks have a pipeline interconnection, thereby forming a single LNG storage and unloading system.

[0015] The complex has the following design options.

[0016] The complex may comprise two GBSs, wherein said fractionation device is mounted on one or each of the two production lines, and wherein at least one said storage tank for each mixed refrigerant component is mounted on one or each of the two GBSs.

[0017] The complex may comprise at least three GBSs, wherein said fractionation apparatus is installed on at least two production lines, and at least one of each of said storage tanks for each mixed refrigerant component is installed in at least two respective GBSs.

[0018] For a two GBS complex, at least one of the SGC tanks is installed in one or each of the two GBSs.

[0019] For a complex of three or more GBSs, at least one SGC tank is installed in at least two GBSs.

[0020] In addition, for three or more GBS complexes, at least two GBSs have LNG and SGC unloading terminals.

[0021] Each production line may include a nitrogen system including an air separation unit, a nitrogen storage tank and a nitrogen vaporizer, wherein one production line also has a backup air separation unit and the nitrogen systems have pipeline interconnections to form a single nitrogen supply system.

[0022] Each production line may include an air compressor unit, wherein both production lines have a backup air compressor unit, and the air compressor units have piping interconnecting them to form a single compressed air supply system.

[0023] Each production line may include an air dryer unit, wherein both production lines have backup air dryer units, and the air dryer units have ducting interconnected to form a single dry air system.

[0024] It is proposed that each GBS has a power reactor, wherein all the power reactors are interconnected with cables to form a single power supply system, each power reactor has a gas turbine generator (GTG), and each of the two power reactors has a spare GTG. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the production complex on GBS is shown.

[0026] Figure 2 A top view of a GBS production line is shown.

[0027] Figure 3 Shows Figure 1 Cross section AA.

[0028] Figure 4 Shows Figure 1 Longitudinal section BB.

[0029] Figure 5 Schematic diagram showing the SGC storage and offloading system

[0030] Figure 6 A schematic diagram of the WFLH fractionation and mixed refrigerant component make-up system is shown.

[0031] Figure 7 A schematic diagram of an LNG storage and offloading system is shown.

[0032] Figure 8 A schematic diagram of the nitrogen system is shown.

[0033] Fig. 9 The power supply system scheme is shown.

[0034] Fig.10 A schematic diagram of an air compressor arrangement is shown.

[0035] Fig.11 A schematic diagram of an air dryer arrangement is shown. DETAILED DESCRIPTION

[0036] A liquefied natural gas (LNG) production complex on a gravity-fed structure (GBS) is a combination of processing, engineering and auxiliary equipment for the production, storage and unloading of LNG and SGC. The complex may consist of two or more production lines on a gravity-fed structure (GBS).

[0037] The attached figure depicts an example complex comprising three production lines 1, 2, 3, each located on a dedicated GBS 4, 5, 6 ( Figure 1 Each production line 1 (2, 3) and its respective GBS 4 (5, 6) are prefabricated products manufactured by a specialist company and then towed to their installation site. Production line 1 (2) on GBS 4 (5) may have a pier 7 (8) to unload the product into a tanker ( Figure 2 ). On site, GBS 4-6 is installed near a dedicated pier on a dedicated base foundation 22 on the seabed ( Figure 3 , Figure 4 ). The production lines 1-3 on GBS 4-6 are interconnected by pipelines and cables installed on the skybridge 9, thereby integrating the production lines 1-3 into a single production complex. Each GBS is also connected to the coast by skybridges and bridges, so that the corresponding pipelines and cables can be installed on the coast without the help of underwater pipelines and / or long cross-water skybridges, and the production complex can be easily accessed and personnel can be evacuated quickly. The short distance to the coast allows simpler and cheaper integration with onshore facilities (including hydrocarbon gas fields), and raw materials are supplied from hydrocarbon gas fields to the production complex.

[0038] On the coast near the production line 1-3, a high-pressure flare 10 and a universal economic device 11 were installed for common use by the entire complex ( Figure 1 ).

[0039] Each production line 1-3 is the upper part of GBS 4-6 (modular processing equipment) ( Figure 2 , Figure 3 , Figure 4 The main processing equipment to complete the gas processing and liquefaction processing sequence is ( Figure 2 ): inlet facility device 28, including raw gas receiving and processing device and gas condensate stabilization device; gas dehydration device 29 and mercury removal device 30; WFLH extraction device 31 and distillation device 32; gas liquefaction device 33; mixed refrigerant compressor devices 34 and 35; evaporation gas compressor device 36; fuel gas device 37 and heating medium system device 38.

[0040] The main processing units on both sides of the GBS as well as the power furnace 43, emergency diesel generator 44, nitrogen system unit 45, air compressor unit 46 and air dryer unit 47 are connected by pipelines, cable racks and bridges through interconnecting modules 39-42.

[0041] GBS 4-6 are three-dimensional structures made of reinforced concrete, the function of which is to store the extracted and processed raw gas as well as auxiliary substances and materials. They are located below the upper part (production lines 1-3) and are designed to be installed on the seabed of the water body by their own weight. The central part 12 of the GBS is a rectangular prism with a top plate 13 ( Figure 3 and Figure 4 ).

[0042] On both sides of the central portion 12 along its periphery, the GBS has protrusions 14 , the protrusions 14 having vertical outer walls, the GBS central portion 12 and the protrusions 14 share a bottom plate 15 , and the protrusions 14 are lower than the central portion 12 .

[0043] The GBS center 12 is divided into compartments by vertical longitudinal walls and transverse walls 16. Some compartments (such as compartments 17 and 18) are used for product (LNG and SGC) storage, while other compartments (such as compartments 19, 20 and 21) are used for ballast water. The GBS protrusion 14 is divided into compartments 20 along the periphery of the GBS by vertical walls perpendicular to its outer walls, which compartments are also included in the ballast system.

[0044] The GBS top plate 13 is provided with reinforced concrete supports 24 on which the top modules are mounted.

[0045] GBS 4-6 can remain afloat when transported to the integrated production complex site and can withstand ice shock in freezing conditions. The GBS 4-6 is ensured to be in a stationary state from a floating state at the installation site on the foundation 22 by flooding the ballast tanks 19, 20, 21 with water.

[0046] In order to prevent the bed layer below the GBS 4-6 and the water body bed layer from being scoured, a seabed reinforcement member 23, such as a gabion or other similar device ( Figure 3 ).

[0047] The technical processes of the GBS LNG production complex do not differ fundamentally from the mixed refrigerant processing technology used in onshore plants. Each process line using mixed refrigerants to liquefy natural gas contains an inlet facility unit 28, which includes equipment for receiving and processing raw gas and gas condensate stabilization. Raw gas and condensate from the site are transported to the inlet facility unit 28 via a skybridge 9, where raw gas reception, pressure control, liquid condensate (hydrocarbons and water) separation, removal of carbon dioxide, hydrogen sulfide, methanol and other impurities from the raw gas, and gas condensate stabilization are carried out.

[0048] Stable gas condensate (SGC) is delivered to a capacity of approximately 75,000m 3 Storage tanks ( Figure 3). At least one concrete compartment 18 with dimensions of 135 x 30 x 30 m is used as a SGC storage tank, with its outer structure acting as a protective barrier. The SGC storage adopts a "wet" storage involving a water layer below. In this case, the bottom layer of the stored product, about 1 m thick, is considered as a mixing zone, ensuring that the water and the stored product are separated during the loading operation. The compartment 18 is slightly pressurized (from the atmospheric pressure level) using a nitrogen cushion in the upper part of the compartment, thus preventing air from penetrating into the compartment and preventing the formation of any flammable and explosive gas mixture with hydrocarbon vapors.

[0049] SGC storage and offloading system ( Figure 5 ) is common to the entire production complex, condensate can be pumped between at least two production lines via onshore pipelines, making it possible not to have an SGC tank in each GBS. If the complex contains two GBSs, the SGC tank can be located in one or both of the GBSs. If the complex consists of at least three GBSs, the SGC tank should be placed in at least two GBSs, in this example only in GBSs 4 and 5, where SGC is also sent to storage from the third production line 3 that does not have a condensate tank.

[0050] The treated raw gas is sent to the dehydration unit 29 and the mercury removal unit 30 in sequence, where mercury, water and residual methanol are removed from the raw gas, and then sent to the wide-fraction light hydrocarbon (WFLH) extraction unit 31. In the WFLH extraction unit 31, ethane, propane, butane and NGL fractions are extracted from the treated gas and then sent to liquefaction.

[0051] At least one production line has a WFLH fractionation device 32. The ethane, propane and butane produced by the device are used for mixed refrigerant component replenishment. The mixed refrigerant component replenishment system 48 is common to the entire complex. The refrigerant components can be pumped between the production lines through onshore pipelines. If the complex has two GBSs and two production lines, the fractionation device can be placed on one or both of the production lines. If the complex contains at least three production lines, it is sufficient to place the fractionation device on at least two of the production lines. In this example, the fractionation device is installed on the first and second production lines 1 and 2 ( Figure 6 ), in which the hydrocarbons extracted from the gas are fractionated to produce ethane, propane and butane fractions. The remaining stable heavy hydrocarbons are sent to the SGC tank-tank 18.

[0052] In order to store the mixed refrigerant components in at least one GBS in the case of at least three GBSs - in at least two GBSs, in the present example in the first and second GBSs 4 and 5, separate storage tanks 27 are provided, at least one storage tank 27 for each mixed refrigerant component, for replenishment of the mixed refrigerant components in all three production lines 1-3, including production line 3 without fractionation means and mixed refrigerant component storage tanks ( Figure 6 ). The WFLH extracted in the third GBS 6 is returned to the treated gas stream to the liquefaction unit, or sent to the WFLH fractionation unit installed in GBS 4 or 5. If the complex has two GBSs, the storage tanks for each mixed refrigerant component may be located in one or both GBSs with the fractionation unit. In the case of at least three GBSs, having the fractionation unit and the storage tanks for each mixed refrigerant component in at least two production lines (1 and 2) can ensure the duplication of this vital equipment. All storage tanks 27 for each mixed refrigerant component have pipeline connections to the refrigerant processing and compression systems of each production line, thereby forming a single mixed refrigerant component replenishment system 48.

[0053] The treated gas is sent to the liquefaction unit 33, in which three coiled heat exchangers are installed one after another for cooling the gas, followed by throttling and generating a liquefied fraction (LNG) and boil-off gas. Three mixed refrigerants with different compositions (a mixture of nitrogen, methane, ethane, propane and butane) are used for gas cooling in the heat exchangers. The liquefied gas is sent to the LNG storage tank 25 housed in each GBS 4-6. The LNG storage tank 25 has a pipeline interconnection to form a single LNG storage and unloading system. The LNG storage and unloading system ( Figure 7 , Fig.10 ) is common to the entire production complex, and LNG can be pumped between tanks 25 in various GBSs via onshore pipelines, thereby maximizing the utilization of total tank capacity.

[0054] Each GBS 4-6 can accommodate at least one, or preferably two, tanks 25 for storing LNG, each with a capacity of 115,000 cubic meters. Thus, the total capacity of the tanks 25 in the production complex is about 690,000 cubic meters. Membrane tanks are used to store LNG. In this case, the tanks 25 consist of a steel membrane made of stainless steel or Invar (Fe-Ni alloy) and separated from the concrete structure by an insulating layer, installed in a concrete compartment 17 ( Figure 3 , Figure 4). The insulation layer is placed directly on the top plate 13, the middle plate 26 and the GBS wall 16, transferring the load of the tank 25 and its LNG content to the above-mentioned closed structure. Therefore, the GBS plate and wall serve as a supporting structure for the membrane tank 25, and they are integrated into a single structure with the membrane tank 25. In order to prevent any leakage, the bottom and sides of the membrane tank 25 have a secondary barrier, that is, an additional membrane installed inside the insulation layer.

[0055] The tanks for ethane (mixed refrigerant component) have a similar membrane structure but with a smaller capacity. GBS 4 and 5 each have one ethane tank, each with a capacity of approximately 1,200 m3 ( Figure 3 and Figure 6 ).

[0056] Self-supporting tanks installed in the GBS 4 and 5 compartments are used for other mixed refrigerant components - butane and propane. The above two GBS 4 and 5 have a capacity of 280m 3 Butane tank with a capacity of 280m 3 Propane tanks ( Figure 3 and Figure 6 ).

[0057] The tanks 27 for each mixed refrigerant assembly are located within the GBS as close as possible to the associated processing equipment where the assemblies are used, thereby optimizing the lengths of piping, electrical heat tracing, and insulation.

[0058] The refrigerant is processed and compressed in the mixed refrigerant compressor units 34 and 35 ( Figure 2 ). Each of the three mixed refrigerant circuits has two parallel strings A and B in the form of two independent units with a capacity of 50% of full capacity. This allows the production complex to operate at 50% capacity even when half of the compressor units are shut down.

[0059] Each unit has two compressors located on one shaft and one frame. Each pair of compressors is driven by one gas turbine drive, thus reducing the number of gas turbine drives. All drives have the same capacity and are completely unified, which simplifies their operation and maintenance.

[0060] The ethane, propane and butane extracted from the WFLH at the fractionation unit 32 are stored in the storage tank 27 for replenishment at GBS1 and 2, and these ethane, propane and butane are used to produce refrigerant. Methane replenishment is carried out using treated raw gas and boil-off gas. Nitrogen for refrigerant replenishment is produced in the 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 evaporator 51 ( Figure 8). Line 1 houses 2x 100% configured integrated air separation units 49 (one unit in operation and one unit on standby), while lines 2 and 3 are equipped with 1x 100% configured air separation unit 49. Line 1 and the ability to pump nitrogen between lines ensures nitrogen production redundancy for the entire production complex. In addition to mixed refrigerant makeup, nitrogen is used to create inert media and gas cushions, purges, compressor dry gas seals, and as a backup source of purge gas.

[0061] The boil-off gas generated in the liquefaction unit 33, the LNG storage tank 25 and the cargo hold of the gas carrier during unloading is sent to the boil-off gas compressor unit 36 ​​for boil-off gas compression and distribution. The boil-off gas is partially used for processing in the gas unit 37 and is mainly consumed by the gas turbine of the power furnace and the mixed refrigerant compressor unit.

[0062] The entire production complex shares a common power supply system ( Fig. 9 ). The system is based on a gas turbine power furnace 43 in each production line 1-3. Each power furnace 43 in production lines 1 and 2 has three gas turbine generators 52 (GTG), including two in operation and one on standby, while production line 3 has two GTGs 52. The GTG 52 of the power furnace and the turbine drive of the mixed refrigerant compressor use a unified gas turbine, which makes the operation and maintenance of the equipment easier and cheaper. The gas turbine is equipped with a device for recovering waste heat for heating the heating medium in the heating medium system device 38.

[0063] The emergency diesel generator 44 serves as a backup power source. Since the power furnaces 43 on the three production lines form a single power supply system by crossing the cables of the overpass 9, N+2 power generation backup arrangements can be achieved.

[0064] Similar conservation principles are applied to air compressors and air dryers, and the air supply systems of the three production lines are interconnected.

[0065] The air compressor units 46 for production lines 1 and 2 are installed in a 3х50% arrangement (two in operation, one on standby), while the air compressor unit 46 for production line 3 is installed in a 2х50% arrangement ( Fig.10 ). The spare capacity of production lines 1 and 2 ensures the spare capacity of the air compressor unit of production line 3.

[0066] Air dryer units 47 are installed on each production line, and two of the production lines are also equipped with standby air dryer units. On production lines 1 and 2, these units are installed in a 3х50% arrangement (two in operation and one on standby), while on production line 3, the air dryer units are installed in a 2х50% arrangement ( Fig.11). The spare air dryer units 47 for lines 1 and 2 ensure the spare of the air dryer unit 47 on line 3. The dry air is used to build up pressure in the gas turbine engine and provides barrier air for the coupling of the gas turbine drive of the mixed refrigerant compressor.

[0067] LNG is unloaded into tankers transporting liquefied gas through terminals 7 and 8, which are only installed on certain lines, such as lines 1 and 2 and GBS 4 and 5 ( Figure 1 ). Terminals 7 and 8 are also used for SGC unloading. The products of Line 3 are unloaded at the terminals of Lines 1 and 2 through the LNG and SGC storage and unloading system.

[0068] The unloading piers 7 and 8 are structurally integrated with the GBS 4 and 5 and the upper part. Fenders and a technical platform with loading and unloading arms and other vessels and processing equipment for LNG and SGC unloading are installed on the protrusion 14 on the berthing side of the GBS. Mooring equipment for tanker berthing is installed on the berthing side of the GBS. The waters near the piers 7 and 8 may have seabed reinforcements 23 to protect the bottom soil from scouring by the ship propellers ( Figure 3 ).

[0069] The production lines 1-3 are interconnected by cables and pipelines on the skybridge 9 and the quayside. The same skybridge 9 is also used to connect the production complex to the gas fields and other onshore facilities.

[0070] Reference numerals list

[0071] 1. Production line (GBS upper part)

[0072] 2. Production line (GBS upper part)

[0073] 3. Production line (GBS upper part)

[0074] 4. GBS

[0075] 5. GBS

[0076] 6. GBS

[0077] 7. Tanker Terminal

[0078] 8. Tanker Terminal

[0079] 9. Interconnection Skybridge

[0080] 10. High pressure torch

[0081] 11. General economic objects

[0082] 12.GBS Center Department

[0083] 13. Top plate of GBS center

[0084] 14. GBS protrusion

[0085] 15.GBS base plate

[0086] 16.GBS vertical wall

[0087] 17.LNG storage tank

[0088] 18.SGC storage compartment

[0089] 19. Internal ballast tank

[0090] 20. External ballast tanks

[0091] 21. The internal ballast tank under the middle support plate of the LNG storage tank

[0092] 22.GBS base foundation

[0093] 23. Seabed reinforcement

[0094] 24. Top support

[0095] 25.LNG storage tank

[0096] 26.Support plate of LNG storage tank

[0097] 27. Mixed refrigerant component storage tank

[0098] 28. Entrance facilities and devices

[0099] 29. Gas dehydration device

[0100] 30. Mercury removal device

[0101] 31.WFLH extraction device

[0102] 32. Fractionation device

[0103] 33. Gas liquefaction plant

[0104] 34.Mixed refrigerant compressor device (production line A)

[0105] 35.Mixed refrigerant compressor device (production line B)

[0106] 36. Evaporative gas compressor device

[0107] 37. Gas installation

[0108] 38. Heating medium system device

[0109] 39. First interconnection module

[0110] 40. Second interconnection module

[0111] 41. The third interconnection module

[0112] 42. Fourth interconnection module

[0113] 43. Power furnace

[0114] 44. Emergency diesel generator

[0115] 45.Nitrogen system device

[0116] 46. ​​Air compressor device

[0117] 47. Air dryer device

[0118] 48.Mixed refrigerant component replenishment system

[0119] 49. Air separation unit

[0120] 50. Nitrogen storage tank

[0121] 51. Nitrogen vaporizer

[0122] 52. Gas turbine generator

[0123] 53. Docklands

[0124] 54. Seabed

[0125] 55. Water level.

Claims

1. A liquefied natural gas (LNG) production complex comprising at least two gravity structures (GBS), each of which houses a natural gas liquefaction production line using a mixed refrigerant, 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 processing and compression system, and a liquefaction unit, in, at least one GBS line comprises a fractionation unit to produce a mixed refrigerant component from the WFLH, wherein at least one respective GBS has at least one storage tank for each mixed refrigerant component, Each GBS has at least one LNG storage tank. wherein at least one GBS has at least one stable gas condensate (SGC) storage tank, At least one GBS has a terminal for unloading LNG and SGC. Features at least one of each storage tank for each mixed refrigerant component has a piping connection to the refrigerant handling and compression system of each production line, thereby forming a single mixed refrigerant component replenishment system, at least one SGC storage tank with a pipeline connection to the condensate stabilization unit for each production line, thereby forming a single SGC storage and unloading system, The LNG tanks are interconnected with pipelines to form a single LNG storage and offloading system.

2. The complex according to claim 1, characterized in that It comprises two GBSs, wherein the fractionation device is installed on one or each of the two production lines, and at least one storage tank for each mixed refrigerant component is installed in one or each of the two GBSs.

3. The complex according to claim 1, characterized in that: It comprises at least three GBSs, wherein the fractionation device is installed on at least two production lines, and at least one of each storage tank of each mixed refrigerant component is installed in at least two corresponding GBSs.

4. The complex according to claim 1, characterized in that: It comprises two GBSs, wherein at least one SGC tank is installed in one or each of the two GBSs.

5. The complex according to claim 1, characterized in that It comprises at least three GBSs, wherein at least one SGC tank is installed in at least two GBSs.

6. The complex according to claim 1, characterized in that It includes at least three GBSs, of which at least two GBSs are equipped with LNG and SGC unloading terminals.

7. The complex according to claim 1, characterized in that: Each production line includes a nitrogen system including an air separation unit, a nitrogen storage tank and a nitrogen evaporator, wherein one production line also has a backup air separation unit, and the nitrogen system has pipeline interconnections to form a single nitrogen supply system.

8. The complex according to claim 1, characterized in that: Each production line includes an air compressor unit, wherein two production lines have a backup air compressor unit, and the air compressor units have piping interconnected to form a single compressed air supply system.

9. The complex according to claim 1, characterized in that: Each production line includes an air dryer unit, wherein two production lines have backup air dryer units, and the air dryer units have ducting interconnections to form a single dry air system.

10. The complex according to claim 1, characterized in that Each GBS houses a power reactor, wherein all the power reactors are cable interconnected to form a single power supply system, each power reactor has a gas turbine generator (GTG), and each of the two power reactors has a spare GTG.

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