Energy supply system for floating production storage and offloading unit, floating production storage and offloading unit

Abstract

The present application relates to an energy supply system for a floating production storage and offloading unit and a floating production storage and offloading unit, with high efficiency, including: a first-stage high-pressure compressor and a second-stage high-pressure compressor, which are respectively connected to the air inlet and the air outlet of the water / hydrocarbon dew point adjustment unit; a high / low-pressure gas treatment unit, the gas inlet of the high / low-pressure gas treatment unit is connected to the air outlet of the water / hydrocarbon dew point adjustment unit; a dual-fuel engine for supplying power to the ship's power grid; a gas turbine, coaxially driving the first-stage high-pressure compressor and the second-stage high-pressure compressor, its gas inlet is connected to the air outlet of the high / low-pressure gas treatment unit, and a waste heat recovery unit is connected to the flue gas outlet of the gas turbine, and the waste heat recovery unit is connected to the hot water pipe network to form a heating circuit; a fuel gas methane value improvement unit, the gas inlet of the fuel gas methane value improvement unit is connected to the air outlet of the water / hydrocarbon dew point adjustment unit, and the gas outlet is connected to the gas inlet of the dual-fuel engine.

Description

Technical Field

[0001] The present application relates to the technical field of floating production units, and particularly to an energy supply system for a floating production, storage and offloading unit. Background Art

[0002] Traditional FPSOs (Floating, Production, Storage and Offloading) usually use gas turbine generators (GTGs, Gas Turbine Compressors) for energy supply. In this system, the gas turbine drives a generator to supply power, and the generated flue gas is used for heating through a waste heat recovery system. However, the gas turbine system has a large footprint, high process complexity, relatively low single gas turbine efficiency, high investment cost, and a long supply cycle.

[0003] Dual fuel engines (DFEs, Dual Fuel Engines) are commonly used for driving or energy supply of floating equipment such as offshore oil and gas platforms / LNGCs (Liquefied Natural Gas Carriers) / merchant ships. They have relatively low investment costs and process complexity, and higher power generation efficiency compared to gas turbines.

[0004] DFEs require a relatively high methane number (MN, Methane Number) for the gas used. However, the methane content in the associated oilfield gas produced by FPSOs is usually relatively low, and usually contains more heavy components with more than two carbon atoms. The methane number is usually below 60. When using this component gas in a dual fuel engine, combustion is difficult to be complete, and it is prone to knocking, which affects the service life and has a relatively high safety risk. Summary of the Invention

[0005] Based on this, it is necessary to propose an energy supply system for a floating production, storage and offloading unit, which can solve the problems of low efficiency and complex process of the existing energy supply system. Also proposed is a floating production, storage and offloading unit.

[0006] According to one aspect of the present application, an energy supply system for a floating production, storage and offloading unit includes: a primary high-pressure compressor and a secondary high-pressure compressor, which are respectively located upstream and downstream of a water / hydrocarbon dew point adjustment unit in a natural gas production system, and are respectively connected to the inlet and outlet of the water / hydrocarbon dew point adjustment unit; a dual-fuel engine for supplying power to the entire-ship power grid of the floating production, storage and offloading unit; a high / low-pressure gas treatment unit, which is connected to the outlet of the water / hydrocarbon dew point adjustment unit; a gas turbine, which coaxially drives the primary high-pressure compressor and the secondary high-pressure compressor, the gas inlet of the gas turbine is connected to the outlet of the water / hydrocarbon dew point adjustment unit, a waste heat recovery unit is connected to the flue gas outlet of the gas turbine, and the waste heat recovery unit is connected to the hot water pipe network of the floating production, storage and offloading unit to form a heating circuit; a fuel gas methane value enhancement unit configured to be able to enhance the methane value of the gas, the gas inlet of the fuel gas methane value enhancement unit is connected to the outlet of the water / hydrocarbon dew point adjustment unit, and the gas outlet of the fuel gas methane value enhancement unit is connected to the gas inlet of the dual-fuel engine.

[0007] In some embodiments, the high / low-pressure gas treatment unit includes a high-pressure flow path and a low-pressure flow path, the high-pressure flow path is connected to the gas inlet of the gas turbine, and the low-pressure flow path is connected to the gas-consuming equipment on the floating production, storage and offloading unit.

[0008] In some embodiments, the fuel gas methane value enhancement unit includes: a dehydration unit, the inlet of the dehydration unit is connected to the outlet of the water / hydrocarbon dew point adjustment unit; a refrigeration unit, which includes a first heat exchange channel, a second heat exchange channel and a third heat exchange channel, the first heat exchange channel is used to cool the gas flowing out of the dehydration unit; a gas-liquid separator, the gas-phase inlet of the gas-liquid separator is connected to the outlet of the first heat exchange channel, the liquid-phase outlet of the gas-liquid separator is connected to the inlet of the second heat exchange channel, and the gas-phase outlet of the gas-liquid separator is connected to the inlet of the third heat exchange channel.

[0009] In some embodiments, the outlet of the second heat exchange channel is connected to the water / hydrocarbon dew point adjustment unit.

[0010] In some embodiments, the refrigeration unit includes a first cold energy recovery heat exchanger, a refrigerant evaporator, a second cold energy recovery heat exchanger, and a third cold energy recovery heat exchanger, each of which is provided with a part of the first heat exchange channel and is connected in sequence; wherein, a refrigeration module is connected to the refrigerant evaporator to form a refrigeration cycle loop; the second heat exchange channel is provided in the second cold energy recovery heat exchanger; the third heat exchange channel includes a first part provided in the third cold energy recovery heat exchanger and a second part provided in the first cold energy recovery heat exchanger. The inlet of the first part is connected to the gas phase outlet of the gas-liquid separator, the outlet of the first part is connected to the inlet of the second part, and the outlet of the second part is connected to the gas phase inlet of the gas pressure stabilizing buffer tank; the gas outlet of the gas pressure stabilizing buffer tank is connected to the gas inlet of the dual-fuel engine.

[0011] In some embodiments, a first throttle expansion valve is provided between the third cold energy recovery heat exchanger and the gas-liquid separator, and the first throttle expansion valve reduces the pressure and cools the gas flowing out of the third cold energy recovery heat exchanger.

[0012] In some embodiments, a second throttle expansion valve is provided between the gas phase outlet of the gas-liquid separator and the first part of the third heat exchange channel, and the second throttle expansion valve reduces the pressure and cools the gas flowing out of the gas-liquid separator.

[0013] In some embodiments, the liquid outlet of the gas pressure stabilizing buffer tank is connected to the liquid inlet of the crude oil separation unit in the natural gas production system.

[0014] In some embodiments, the refrigeration module is a mechanical refrigeration module.

[0015] On the other hand, the present application proposes a floating production, storage and offloading unit, including the energy supply system of the floating production, storage and offloading unit.

[0016] In the energy supply system of the floating production, storage and offloading unit of the present application, the gas turbine produced by the FPSO is used to drive the first-stage high-pressure compressor and the second-stage high-pressure compressor, and a waste heat recovery unit is included to supply heat to each process unit of the whole ship; the treated natural gas produced by the FPSO is used as the fuel gas of the dual-fuel engine, and there is no detonation risk during use, and the engine does not need to reduce power operation, solving the technical bottleneck that the natural gas produced by the FPSO cannot be used on the engine. Compared with the conventional technology using gas turbines, the process is simple, the functional efficiency is high, the total investment cost is significantly reduced, and the delivery period of the power generation system is significantly shortened. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of a floating production, storage and offloading unit including the energy supply system of the floating production, storage and offloading unit according to an embodiment of the present application.

[0018] Figure 2 It is a schematic diagram of the composition of the fuel gas methane value boosting unit in the energy supply system of a floating production, storage and offloading unit.

[0019] Description of the reference numerals in the drawings:

[0020] 100, floating production, storage and offloading unit; 1, hull; 21, crude oil separation and stabilization unit; 22, low-pressure process compressor; 23, medium-pressure process compressor; 24, water / hydrocarbon dew point adjustment unit; 3, hot water pipe network; 4, ship-wide power grid; 5, upper module; 61, first-stage high-pressure compressor; 62, second-stage high-pressure compressor; 63, dual-fuel engine; 64, gas turbine; 65, fuel gas methane value boosting unit; 651, dehydration unit; 652, refrigeration unit; 6521, first cold energy recovery heat exchanger; 6522, refrigerant evaporator; 6523, second cold energy recovery heat exchanger; 6524, third cold energy recovery heat exchanger; 6255, refrigeration module; 653, gas-liquid separator; 654, gas pressure stabilizing buffer tank; 655, first throttle expansion valve; 656, second throttle expansion valve; 657, condensate electric heater; 66, waste heat recovery unit; 67, high / low-pressure gas treatment unit. Detailed implementation manners

[0021] In order to make the above objects, features and advantages of the present application more obvious and understandable, the following will describe the detailed implementation manners of the present application with reference to the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0022] In the description of the present application, it should be understood that if there are terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., the orientation or positional relationship indicated by these terms is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present application.

[0023] In addition, if the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of this application, if the term "a plurality of" appears, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0024] In this application, unless otherwise clearly specified and defined, if terms such as "installed", "connected", "joined", "fixed", etc. appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0025] In this application, unless otherwise clearly specified and defined, if there is a description such as a first feature being "on" or "under" a second feature, the meaning can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature can mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher horizontal level than the second feature. The first feature being "under", "beneath" and "underneath" the second feature can be that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower horizontal level than the second feature.

[0026] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or there can also be an intermediate element. If an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. If so, the terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used in this application are only for the purpose of illustration and do not represent the only implementation.

[0027] Reference Figure 1 and Figure 2 , Figure 1 FIG. 18 is a schematic structural diagram of a floating production, storage and offloading unit 100 of an energy supply system including the floating production, storage and offloading unit 100 according to an embodiment of the present application. Figure 2 FIG. 20 is a schematic diagram of the composition of a gas methane value boosting system in the energy supply system of the floating production, storage and offloading unit 100.

[0028] One aspect of the present application provides an energy supply system for a floating production storage and offloading unit 100, which can solve the technical bottleneck that the process gas components of FPSO cannot be used in engines, eliminate safety risks, and solve the problems of low efficiency and complex process of the existing energy supply system.

[0029] To facilitate the understanding of the energy supply system of the floating production storage and offloading unit 100 in one aspect of the present application, a brief description of the floating production storage and offloading unit 100 involved in the present application is first given.

[0030] In the embodiments of the present application, "low temperature" and "high temperature" are relative concepts, which means that the temperature of the relatively low-temperature gas of the high-temperature gas is higher, and "normal temperature" is the temperature between low temperature and high temperature; similarly, "low pressure" and "high pressure" are relative concepts, and the pressure of the high-pressure gas is higher than that of the low-pressure gas. Therefore, although the "low temperature", "high temperature", "normal temperature", "low pressure", and "high pressure" in the embodiments of the present application are not limited to specific values, their protection scope is clear when used to express relative concepts.

[0031] The floating production storage and offloading unit 100 includes a hull 1. A natural gas production system, a hot water pipe network 3, a ship-wide power grid 4, and other upper modules 5 are arranged on the hull 1. The other upper modules 5 include, for example, a water treatment module, a flare, etc.

[0032] The natural gas production system includes a crude oil separation and stabilization unit 21, a low-pressure process compressor 22, a medium-pressure process compressor 23, and a water / hydrocarbon dew point adjustment unit 24.

[0033] In the crude oil separation and stabilization unit 21, the crude oil is fully separated into crude oil, produced water, and associated gas through a three-stage oil / gas / water three-phase separator. Among them, the crude oil and the produced water are sent to other process flow units of a conventional FPSO (such as crude oil desalination, water treatment, etc.), and the associated gas goes to different destinations according to different generated pressures.

[0034] In the present application, high / low / medium-pressure three-phase separators are provided in the crude oil separation and stabilization unit 21, and the medium / low-pressure three-phase separators are respectively connected to the low-pressure process compressor 22 and the medium-pressure process compressor 23. The outlets of the low-pressure process compressor 22 and the medium-pressure process compressor 2 converge with the outlet of the high-pressure three-phase separator. In this way, the gas produced by the low-pressure / medium-pressure three-phase separators is compressed by the low-pressure / medium-pressure process compressor 23 respectively, and then converges with the gas produced by the high-pressure three-phase separator and is transported to the water / hydrocarbon dew point adjustment unit 24.

[0035] The water / hydrocarbon dew point adjustment unit 24 is used to adjust and control the water dew point and hydrocarbon dew point in the natural gas, and can be implemented by using the existing technologies in the prior art.

[0036] Reference Figure 1, the energy supply system of the floating production, storage and offloading unit 100 of the present application includes a first-stage high-pressure compressor 61, a second-stage high-pressure compressor 62, a dual-fuel engine 63, a gas turbine 64, and a fuel gas methane value boosting unit 65, a waste heat recovery unit 66, and a high / low-pressure gas treatment unit 67.

[0037] Specifically, the first-stage high-pressure compressor 61 and the second-stage high-pressure compressor 62 are respectively located upstream and downstream of the water / hydrocarbon dew point adjustment unit 24 in the natural gas production system, and are respectively connected to the inlet and outlet of the water / hydrocarbon dew point adjustment unit 24. The first-stage high-pressure compressor 61 is used to further compress the converging gas flow of the high / medium / low-pressure three-phase separator and then input it into the water / hydrocarbon dew point adjustment unit 24. The second-stage high-pressure compressor 62 is used to further compress the natural gas processed by the water / hydrocarbon dew point adjustment unit 24 and then export it as product gas. The gas flow flowing out of the outlet of the water / hydrocarbon dew point adjustment unit 24 includes two paths, one path flows to the second-stage high-pressure compressor 62, and the other path flows to the fuel gas methane value boosting unit 65.

[0038] The dual-fuel engine 63 is used to supply power to the ship-wide power grid 4 of the floating production, storage and offloading unit 100. The dual-fuel engine 63 is responsible for supplying power to the ship-wide power grid 4. The dual-fuel engine 63 can generate electricity using gas or fuel oil. The fuel oil is diesel, for example.

[0039] The gas turbine 64 coaxially drives the first-stage high-pressure compressor 61 and the second-stage high-pressure compressor 62. The gas inlet of the gas turbine 64 is connected to the outlet of the high / low-pressure gas treatment unit 67. The gas inlet of the high / low-pressure gas treatment unit 67 is connected to the outlet of the water / hydrocarbon dew point adjustment unit 24. A waste heat recovery unit 66 is connected to the flue gas outlet of the gas turbine 64, and the waste heat recovery unit 66 is connected to the hot water pipe network 3 of the floating production, storage and offloading unit 100 to form a heating circuit.

[0040] The gas turbine 64 coaxially drives the first-stage high-pressure compressor 61 and the second-stage high-pressure compressor 62, that is, the drive shaft of the gas turbine 64 is used to drive the first-stage high-pressure compressor 61 and the second-stage high-pressure compressor 62, so that there is no need to separately configure a drive mechanism for the first-stage high-pressure compressor 61 and the second-stage high-pressure compressor 62. At the same time, the heat of the flue gas discharged by the gas turbine 64 is recovered by the waste heat recovery unit 66 and used to supply heat to the ship-wide hot water pipe network 3.

[0041] The fuel gas methane value boosting unit 65 is configured to be able to boost the methane value of the gas. The gas inlet of the fuel gas methane value boosting unit 65 is connected to the outlet of the water / hydrocarbon dew point adjustment unit 24, and the gas outlet of the fuel gas methane value boosting unit 65 is connected to the gas inlet of the dual-fuel engine 63.

[0042] The fuel gas methane value boosting unit 65 reduces the content of heavy components above C2 and increases the content of C1 in the fuel gas, thereby increasing the methane value of the fuel gas and making it meet the specifications before supplying it as fuel gas to the dual-fuel engine 63 to supply power to the ship's power grid 4. The processed natural gas is supplied as fuel gas to the dual-fuel engine 63, and there is no detonation risk during use.

[0043] Optionally, the fuel gas methane value boosting unit 65 uses the direct refrigeration and pressure reduction separation technology to remove components above C2 and enrich the methane component from the natural gas produced by the FPSO, and can boost the methane value of the fuel gas from below 60 to above 80 at most.

[0044] The energy supply system of the floating production, storage and offloading unit 100 of the present application uses the natural gas produced by the FPSO to drive the first-stage high-pressure compressor 61 and the second-stage high-pressure compressor 62 through a gas turbine, and includes a waste heat recovery unit 66 to supply heat to each process unit of the whole ship; uses the processed natural gas produced by the FPSO as the fuel gas of the dual-fuel engine 63, and there is no detonation risk during use, and the engine does not need to operate at reduced power, solving the technical bottleneck that the natural gas produced by the FPSO cannot be used on the engine. Compared with the conventional technology using a gas turbine, the process is simple, the efficiency is high, the total investment cost is significantly reduced, and the delivery period of the power generation system is significantly shortened.

[0045] In some embodiments, the high / low-pressure gas treatment unit 67 includes a high-pressure flow path and a low-pressure flow path. The high-pressure flow path is communicated with the gas inlet of the gas turbine 64, and the low-pressure flow path is communicated with the gas-using equipment on the floating production, storage and offloading unit 100.

[0046] The high / low-pressure gas treatment unit 67 adjusts the pressure and temperature of the natural gas flowing out of the outlet of the water / hydrocarbon dew point adjustment unit 24, and supplies the high-pressure gas to the gas turbine 64 through the high-pressure flow path, and supplies the low-pressure gas to other gas-using equipment on the floating production, storage and offloading unit 100 through the low-pressure flow path.

[0047] Reference Figure 1 and Figure 2 , the fuel gas methane value boosting unit 65 is used to supply the processed fuel gas with a qualified methane value to the dual-fuel engine 63. In some embodiments, the fuel gas methane value boosting unit 65 includes a dehydration unit 651, a refrigeration unit 652 and a gas-liquid separator 653.

[0048] The inlet of the dehydration unit 651 is communicated with the outlet of the water / hydrocarbon dew point adjustment unit 24. The inlet gas of the dehydration unit 651 comes from the outlet of the water / hydrocarbon dew point adjustment unit 24. The dehydration unit 651 includes, for example, a molecular sieve dehydration system to adsorb and dry the natural gas to reduce the water content to ensure that there is no formation of natural gas hydrates causing blockage in the subsequent process.

[0049] The refrigeration unit 652 includes a first heat exchange channel, a second heat exchange channel, and a third heat exchange channel. The first heat exchange channel is used to cool the gas flowing out of the dehydration unit 651.

[0050] The gas-phase inlet of the gas-liquid separator 653 is communicated with the outlet of the first heat exchange channel. The liquid-phase outlet of the gas-liquid separator 653 is communicated with the inlet of the second heat exchange channel. The gas-phase outlet of the gas-liquid separator 653 is communicated with the inlet of the third heat exchange channel.

[0051] As Figure 2 shown, in one example, the refrigeration unit 652 includes a first cold recovery heat exchanger 6521, a refrigerant evaporator 6522, a second cold recovery heat exchanger 6523, and a third cold recovery heat exchanger 6524, each of which is provided with a part of the first heat exchange channel and is sequentially communicated. A refrigeration module 6255 is connected to the refrigerant evaporator 6522 to form a refrigeration cycle loop. The second heat exchange channel is provided in the second cold recovery heat exchanger 6523. The third heat exchange channel includes a first part provided in the third cold recovery heat exchanger 6524 and a second part provided in the first cold recovery heat exchanger 6521. The inlet of the first part is communicated with the gas-phase outlet of the gas-liquid separator 653. The outlet of the first part is communicated with the inlet of the second part. The outlet of the second part is communicated with the gas-phase inlet of the gas pressure stabilizing buffer tank 654. The gas outlet of the gas pressure stabilizing buffer tank 654 is communicated with the gas inlet of the dual-fuel engine 63.

[0052] Specifically, in this embodiment, each of the first cold recovery heat exchanger 6521, the refrigerant evaporator 6522, the second cold recovery heat exchanger 6523, and the third cold recovery heat exchanger 6524 is provided with a part of the first heat exchange channel, and each part is communicated through a pipeline. The gas-phase inlet of the gas-liquid separator 653 is communicated with the outlet of the first heat exchange channel provided on the third cold recovery heat exchanger 6524.

[0053] The natural gas flowing out of the outlet of the dehydration unit 651 is cooled multiple times through the first cold recovery heat exchanger 6521, the refrigerant evaporator 6522, the second cold recovery heat exchanger 6523, and the third cold recovery heat exchanger 6524 in sequence, and then reaches the gas-phase inlet of the gas-liquid separator 653.

[0054] Both the first cold recovery heat exchanger 6521 and the third cold recovery heat exchanger 6524 utilize the low-temperature and low-pressure gas processed by the downstream gas-liquid separator 653 to circulate back and cool the gas with relatively higher pressure and temperature that has not been processed by the gas-liquid separator 653. The natural gas flowing out of the gas-phase outlet of the gas-liquid separator 653 flows through the third cold recovery heat exchanger 6524 and the first cold recovery heat exchanger 6521 in sequence. The first part and the second part of the third heat exchange channel can be communicated through a pipeline.

[0055] The second cold energy recovery heat exchanger 6523 uses the low-temperature heavy component condensate separated by the downstream gas-liquid separator 653 to circulate back and cool the fuel gas.

[0056] The refrigerant evaporator 6522 uses an external refrigeration module 6255 to directly cool the fuel gas. The refrigerant evaporator 6522 and the refrigeration module 6255 form a refrigeration circuit. The refrigeration module 6255 can be, for example, a mechanical refrigeration module 6255. The mechanical refrigeration module 6255 includes, for example, a compressor, a condenser, and an expansion valve. The compressor transports the refrigerant through the condenser and then through the expansion valve to the inlet of the refrigerant evaporator 6522 in sequence, and then returns to the compressor through the outlet of the refrigerant evaporator 6522.

[0057] With such a design, the cooling effect of the refrigeration unit 652 is ensured by the refrigerant evaporator 6522 and the external refrigeration module 6255; at the same time, the temperature and enthalpy value of the fuel gas after being processed by the gas-liquid separator 653 are fully utilized, reducing the overall energy consumption while optimizing the cooling performance. Moreover, this four-stage cooling can reduce energy consumption and extend the equipment life.

[0058] It should also be pointed out that the composition scheme of the refrigeration unit 652 including three heat exchange channels is not limited to the above-described embodiments.

[0059] Furthermore, a first throttle expansion valve 655 is provided between the third cold energy recovery heat exchanger 6524 and the gas-liquid separator 653, and the first throttle expansion valve 655 reduces the pressure and cools the gas flowing out of the third cold energy recovery heat exchanger 6524.

[0060] Specifically, the natural gas flowing out of the first heat exchange channel on the third cold energy recovery heat exchanger 6524 first passes through the first throttle expansion valve 655 and then enters the gas-phase inlet of the gas-liquid separator 653. The first throttle expansion valve 655 cools the natural gas flowing out of the first heat exchange channel. During this process, the natural gas realizes pressure reduction and temperature reduction through the Joule-Thomson effect. The temperature of the natural gas is further reduced, so that the heavy components above C2 are fully liquefied and then enter the gas-liquid separator 653 for gas-liquid separation. At this time, the heavier components above C2 form condensate, which flows out from the liquid-phase outlet of the gas-liquid separator 653 and is sent to the second heat exchange channel of the second cold energy recovery heat exchanger 6523. After the second cold energy recovery heat exchanger 6523 recovers the cold energy of the condensate, it is heated by the condensate electric heater 657 and then circulates back to the natural gas production system.

[0061] Optionally, the outlet of the second heat exchange channel is connected to the water / hydrocarbon dew point adjustment unit 24. That is, after the second cold energy recovery heat exchanger 6523 recovers the cold energy of the condensate, it is heated by the condensate electric heater 657 and then recycled into the water / hydrocarbon dew point adjustment unit 24. Specifically, the water / hydrocarbon dew point adjustment unit 24 includes multiple-stage equipment, and the outlet of the second heat exchange channel is connected to a certain stage of equipment in the middle.

[0062] Furthermore, a second throttle expansion valve 656 is provided between the gas phase outlet of the gas-liquid separator 653 and the first part of the third heat exchange channel. The second throttle expansion valve 656 reduces the pressure and cools the gas flowing out of the gas-liquid separator 653.

[0063] Specifically, the natural gas with qualified methane value after being processed by the gas-liquid separator 653 flows out from the gas phase outlet of the gas-liquid separator 653 and is further reduced in pressure and cooled by the second throttle expansion valve 656. This process also realizes pressure reduction and temperature reduction based on the Joule-Thomson effect. The purpose is to further utilize the enthalpy value of natural gas for temperature reduction by releasing the unused mechanical energy of natural gas. The natural gas with qualified methane value after being processed enters the third cold energy recovery heat exchanger and the first cold energy recovery heat exchanger 6521 in sequence to recover the cold energy of natural gas, and then enters the gas pressure stabilizing buffer tank 654 for pressure stabilizing and buffering, and is then sent to the dual-fuel engine 63 of the hull 1 for use.

[0064] After being processed through the above process, most of the components above C2 in natural gas form condensate and are separated out. The content of C1 components in the remaining gas phase is high enough, and finally the methane value of the overall components meets the intake requirements of the engine, and there is no risk of knocking.

[0065] Furthermore, in some embodiments, referring to Figure 2 , the liquid outlet of the gas pressure stabilizing buffer tank 654 is connected to the liquid inlet of the crude oil separation unit in the natural gas production system.

[0066] After entering the third cold energy recovery heat exchanger and the first cold energy recovery heat exchanger 6521 and undergoing pressure stabilizing and buffering treatment in the gas pressure stabilizing buffer tank 654, gas-liquid separation occurs. The gas phase enters the dual-fuel engine 63 of the hull 1 for use; the liquid phase is recycled to the crude oil separation unit.

[0067] On the other hand, the present application proposes a floating production, storage and offloading unit 100, including the energy supply system of the floating production, storage and offloading unit 100.

[0068] For the floating production, storage and offloading unit 100 of the present application, by adopting the above-mentioned energy supply system, the natural gas produced by the FPSO that has been processed can be used as the fuel gas of the dual-fuel engine 63. When in use, there is no detonation risk, and the engine does not need to operate at a reduced power. This solves the technical bottleneck that the natural gas produced by the FPSO cannot be used in the engine. Moreover, compared with the conventional technology of using gas turbines, the process is simple, the efficiency is high, the total investment cost is significantly reduced, and the delivery period of the power generation system is significantly shortened.

[0069] Finally, it should be noted that the technical features of the above-mentioned embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0070] The above-mentioned embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be understood as a limitation to the scope of the patent application. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. An energy supply system for a floating production storage and offloading unit, characterized in that: include: The first-stage high-pressure compressor and the second-stage high-pressure compressor are respectively located upstream and downstream of the water / hydrocarbon dew point regulating unit in the natural gas production system, and are respectively connected to the air inlet and the air outlet of the water / hydrocarbon dew point regulating unit; A high / low pressure gas processing unit, wherein the gas inlet of the high / low pressure gas processing unit is connected to the gas outlet of the water / hydrocarbon dew point regulating unit; A dual-fuel engine for supplying power to the entire shipboard power grid of the floating production storage and offloading unit; a gas turbine, wherein the gas turbine coaxially drives the first-stage high-pressure compressor and the second-stage high-pressure compressor, the gas inlet of the gas turbine is connected to the gas outlet of the high / low-pressure gas processing unit, the flue gas outlet of the gas turbine is connected to a waste heat recovery unit, and the waste heat recovery unit is connected to the hot water pipe network of the floating production storage and offloading device to form a heating circuit; A fuel gas methane number improving unit, wherein the fuel gas methane number improving unit is configured to improve the methane number of the fuel gas, the fuel gas methane number improving unit's fuel gas methane number improving unit's fuel gas inlet is connected to the gas outlet of the water / hydrocarbon dew point regulating unit, and the fuel gas methane number improving unit's fuel gas outlet is connected to the fuel gas inlet of the dual-fuel engine.

2. The energy supply system of the floating production storage and offloading unit according to claim 1, characterized in that: The high / low pressure gas processing unit comprises a high pressure flow path and a low pressure flow path, wherein the high pressure flow path is connected to the gas inlet of the gas turbine, and the low pressure flow path is connected to the gas using equipment on the floating production storage and offloading device.

3. The energy supply system of the floating production storage and offloading unit according to claim 1, characterized in that: The fuel gas methane value improving unit comprises: a dehydration unit, wherein the inlet of the dehydration unit is in communication with the outlet of the water / hydrocarbon dew point adjustment unit; A refrigeration unit, wherein the refrigeration unit comprises a first heat exchange channel, a second heat exchange channel and a third heat exchange channel, wherein the first heat exchange channel is used to cool the gas flowing out of the dehydration unit; A gas-liquid separator, wherein the gas phase inlet of the gas-liquid separator is connected to the outlet of the first heat exchange channel, the liquid phase outlet of the gas-liquid separator is connected to the inlet of the second heat exchange channel, and the gas phase outlet of the gas-liquid separator is connected to the inlet of the third heat exchange channel.

4. The energy supply system of the floating production storage and offloading unit according to claim 3 is characterized in that: An outlet of the second heat exchange passage is in communication with the water / hydrocarbon dew point adjustment unit.

5. The energy supply system of the floating production storage and offloading unit according to claim 3, characterized in that: The refrigeration unit comprises a first cooling recovery heat exchanger, a refrigerant evaporator, a second cooling recovery heat exchanger and a third cooling recovery heat exchanger, each of which is provided with a portion of the first heat exchange channel and is connected in sequence; wherein, The refrigerant evaporator is connected to a refrigeration module to form a refrigeration cycle; The second heat exchange channel is provided in the second cold recovery heat exchanger; The third heat exchange channel includes a first part provided in the third cold recovery heat exchanger and a second part provided in the first cold recovery heat exchanger, the inlet of the first part is communicated with the gas phase outlet of the gas-liquid separator, the outlet of the first part is communicated with the inlet of the second part, and the outlet of the second part is communicated with the gas phase inlet of the gas pressure stabilizing buffer tank; The gas outlet of the gas pressure stabilizing buffer tank is in communication with the gas inlet of the dual-fuel engine.

6. The energy supply system of the floating production storage and offloading unit according to claim 5, characterized in that: A first throttling expansion valve is provided between the third cooling recovery heat exchanger and the gas-liquid separator, and the first throttling expansion valve reduces the pressure and cools the gas flowing out of the third cooling recovery heat exchanger.

7. The energy supply system of the floating production storage and offloading unit according to claim 5, characterized in that: A second throttling expansion valve is provided between the gas phase outlet of the gas-liquid separator and the first portion of the third heat exchange channel, and the second throttling expansion valve reduces the pressure and cools the gas flowing out of the gas-liquid separator.

8. The energy supply system of the floating production storage and offloading unit according to claim 5, characterized in that: The liquid outlet of the fuel gas pressure stabilizing buffer tank is communicated with the liquid inlet of the crude oil separation unit in the natural gas production system.

9. The energy supply system of the floating production storage and offloading unit according to claim 5, characterized in that: The refrigeration module is a mechanical refrigeration module.

10. A floating production storage and offloading unit, characterized in that: A power supply system comprising a floating production storage and offloading unit as claimed in any one of claims 1 to 9.

Images