Combined cycle system for cogeneration on offshore floating production storage and offloading vessels

Abstract

The application relates to a combined heat and power cogeneration combined cycle system for a floating production storage and offloading vessel, comprising: a turbine power generation device for supplying power by driving a generator through fuel and steam and discharging first-temperature flue gas generated when the fuel is burned through a flue gas duct; a recovery cycle device arranged on the flue gas duct and comprising a waste heat steam generator and a waste heat recovery device; the waste heat steam generator uses the first-temperature flue gas as a heat source to form steam, discharges second-temperature flue gas through the flue gas duct after the steam is supplied to the turbine power generation device; the waste heat recovery device uses the second-temperature flue gas as a heat source to pre-heat a heat medium flowing through the waste heat recovery device; and a heater in communication with the waste heat recovery device, used for receiving and discharging steam discharged by the turbine power generation device, so that the heat medium is heated to a preset temperature, high-temperature flue gas is fully utilized, flue gas emission is reduced, and a green carbon reduction target is met.

Description

Technical Field

[0001] This application relates to the field of shipbuilding and marine engineering technology, and in particular to a combined heat and power system for offshore floating production storage and offloading vessels. Background Technology

[0002] Offshore floating platforms refer to offshore processing plants that are suitable for offshore oil and gas development and integrate production, storage, and unloading, such as floating production storage and offloading vessels (FPSOs) and floating liquefied natural gas systems (FLNGs).

[0003] Limited by the space and carrying capacity of the marine environment, the energy supply system of current floating production storage and offloading vessels (FPSOs) suffers from low energy conversion efficiency. A large amount of energy is not effectively utilized, and more than half of the energy is lost as heat in the form of flue gas and other carriers during the conversion process. This not only causes serious energy waste, but also indirectly leads to high emissions of greenhouse gases such as carbon dioxide due to the excessive total energy consumption.

[0004] With global economic development, population growth, and social progress, people's awareness of sustainable development and environmental protection has increased. Therefore, improving the energy efficiency of floating production storage and offloading (FPSO) vessels and controlling carbon emissions has become one of the urgent technical problems to be solved by researchers in this field. Utility Model Content

[0005] Therefore, it is necessary to improve the energy efficiency of floating production storage and offloading (FPSO) vessels and control carbon emissions in related technologies. To achieve this objective, this invention provides a combined heat and power (CHP) system for an FPSO vessel, comprising:

[0006] A turbine generator unit is used to drive a generator to supply electricity via fuel and steam; and the first-temperature flue gas generated during the combustion of the fuel is discharged through an exhaust pipe.

[0007] A recycling device is installed on the flue gas duct, including a waste heat steam generator and a waste heat recovery unit; the waste heat steam generator uses the first temperature flue gas as a heat source to generate steam, which is then supplied to the turbine power generation unit and discharged through the flue gas duct at the second temperature; the waste heat recovery unit uses the second temperature flue gas as a heat source to preheat the heat medium flowing through the waste heat recovery unit.

[0008] The heater, connected to the waste heat recovery unit, is used to receive the heat medium and steam discharged from the turbine power generation unit, and heat the heat medium to a preset temperature.

[0009] In one embodiment, the turbine power generation unit includes:

[0010] A gas turbine is connected at one end to a first generator and at the other end to a waste heat steam generator via a flue pipe. The generator is used to burn fuel to drive the first generator to generate electricity and discharge flue gas at a first temperature.

[0011] The steam turbine is connected to a waste heat steam generator at one end and a second generator at the other end. The steam drives the second generator to generate second electricity and discharges the steam through pipelines.

[0012] The total power output of the first and second power plants ranges from 160MW to 170MW.

[0013] In one embodiment, the temperature range of the first temperature flue gas generated by the gas turbine is 450°C-550°C, and the temperature range of the second temperature flue gas discharged is 200°C-300°C.

[0014] In one embodiment, the heater requires less power than the original power;

[0015] The raw power is used to characterize the power required by the heater to heat the heat medium to a preset temperature when no steam is applied and the heat medium is not preheated;

[0016] The original power is not less than 130MW.

[0017] In one embodiment, a condenser is connected at one end to a heater and at the other end to a waste heat steam generator for receiving steam and cooling and recirculating it.

[0018] In one embodiment, the combined heat and power system further includes:

[0019] The control unit, connected to the turbine generator, the recovery and circulation unit, and the heater, is used to control the turbine generator, the recovery and circulation unit, and the heater to perform corresponding operations upon receiving a demand command for the electrical or thermal load of the offshore floating platform.

[0020] In one embodiment, the recycling device also includes a body;

[0021] The waste heat steam generator and waste heat recovery unit are located at least partially within the main body.

[0022] In one embodiment, the control device includes:

[0023] The data acquisition module is used to collect the operating parameters of the turbine generator, the recycling system, and the heater in real time.

[0024] The early warning module, which communicates with the data acquisition module, is used to generate early warning signals when abnormal operating parameters are detected.

[0025] The display module is used to display operating parameters and warning signals.

[0026] In one embodiment, the combined heat and power cycle system further includes:

[0027] The regulating valve is located in the recycling unit and the turbine power generation unit;

[0028] The control device is used to control the opening degree of the regulating valve upon receiving a demand command for the electrical or thermal load of the offshore floating platform.

[0029] Secondly, this application provides a floating production storage and offloading vessel for offshore use, employing the combined cycle system described in any of the above embodiments.

[0030] The combined heat and power system for offshore floating platforms disclosed herein has the following unexpected beneficial effects:

[0031] Large-scale FPSOs typically have power requirements of approximately 160MW and heat load requirements often exceeding 130MW. Compared to combined cycle systems in related technologies, this application provides a novel combined cycle system. By sequentially connecting a steam generator and a waste heat recovery unit in series on the exhaust pipe of the gas turbine, it fully utilizes the cascaded heat energy of the flue gas to achieve deep extraction and efficient conversion of flue gas heat. Specifically, the high-temperature flue gas (first temperature) first flows through the steam generator to generate steam to drive the turbine for power generation. Subsequently, the cooled flue gas (second temperature) continues to flow through the waste heat recovery unit to preheat the heat transfer medium flowing through it, thereby significantly reducing the heat required for the heat transfer medium to rise in temperature in subsequent processes.

[0032] Therefore, it can not only reliably meet the high intensity requirements of ultra-large FPSOs for electricity (160MW–170MW) and process thermal energy (≥130MW) and reduce the platform's fuel consumption, but also effectively control greenhouse gas emissions such as carbon dioxide during operation by significantly improving the comprehensive energy utilization efficiency. It actively responds to the industry requirements for green, low-carbon and sustainable development of marine engineering equipment and has important engineering application value and environmental benefits. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the circuit principle of a combined heat and power system provided in one embodiment;

[0035] Figure 2 This is a schematic diagram of the connection relationship of a combined heat and power system provided in one embodiment.

[0036] Explanation of reference numerals in the attached figures:

[0037] 1. Turbine generator; 11. Gas turbine; 12. First generator; 13. Steam turbine; 14. Second generator; 2. Recovery and circulation device; 21. Waste heat steam generator; 22. Waste heat recovery unit; 3. Heater; 4. Control device; 5. Condenser. Detailed Implementation

[0038] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0039] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0040] Furthermore, where 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 number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0041] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0042] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0043] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening 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 intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0044] Open-cycle gas turbines (GTGs) equipped with waste heat recovery units (WHRUs) can simultaneously meet the power requirements of floating production storage and offloading (FPSO) units and the heating requirements of process heat transfer media. However, open-cycle gas turbines themselves have low thermal efficiency, typically only around 40%, and this configuration makes it difficult to achieve the minimum greenhouse gas emission targets.

[0045] In related technological fields, combined cycle gas / steam turbine units are gradually replacing traditional gas turbines due to their thermal efficiency of approximately 60%. The combined cycle system, by connecting multiple thermodynamic cycles in series, efficiently converts the chemical energy of fuel into mechanical energy, thereby significantly improving energy utilization efficiency. Specifically, the system first generates electricity through a gas turbine (GTG), and then uses the high-temperature exhaust gas from the gas turbine to generate steam in a heat recovery steam generator (HRSG), which drives a downstream steam turbine (STG) to further generate electricity. This process not only improves the overall fuel utilization efficiency but also significantly reduces exhaust emissions, aligning with the development direction of green carbon reduction. The combined cycle system recovers heat from the gas turbine exhaust gas through the HRSG, generating high-pressure superheated steam to drive the steam turbine to generate electricity, achieving carbon-free power output. The turbine exhaust steam can also be further used to heat process heat transfer media to meet the heating requirements of the process flow.

[0046] However, existing combined cycle systems are typically suitable for small to medium-sized FPSOs with lower heating requirements for the heat transfer medium. For ultra-large FPSOs (daily oil production ≥ 220,000 barrels), their power demand (typically around 160 MW) and heat demand (typically around 130 MW) are extremely large. In such cases, conventional combined cycle systems often struggle to simultaneously meet the high load demands for both electricity and heat, thus limiting their application in ultra-large FPSOs.

[0047] Based on this, please refer to Figure 1 This application provides a combined heat and power (CHP) system for a floating production storage and offloading (FPSO) vessel, comprising: a turbine generator 1, a recovery and circulation device 2, and a heater 3; wherein, the turbine generator 1 is used to drive a generator to supply power through fuel and steam, and to discharge high-temperature flue gas generated during the combustion of the fuel through an exhaust pipe; the recovery and circulation device 2, located on the exhaust pipe, is used to efficiently recover waste heat from the high-temperature flue gas, improve the overall energy utilization efficiency, and achieve effective control of carbon emissions; the heater 3, connected to the turbine generator 1 and the recovery and circulation device 2, is used to heat the heat transfer medium to a preset temperature to meet the process heating requirements.

[0048] In this embodiment, the heat transfer medium includes, but is not limited to, water-based heat transfer medium or organic heat transfer medium, and the specific type can be flexibly selected according to the actual process conditions.

[0049] Please continue reading. Figure 1In some embodiments, the combined heat and power system further includes a control device 4, which is connected to the turbine generator 1, the recycling unit 2 and the heater 3, for receiving power load or heat load demand instructions from the offshore floating platform, and coordinating and controlling each device to perform corresponding operations, thereby achieving optimization and automated management of the overall system operation.

[0050] The following is combined with Figures 1-2 The combined heat and power system provided in this application will be further described in detail with reference to specific embodiments.

[0051] Specifically, please refer to Figure 2 Specifically, the turbine power generation unit 1 includes: a gas turbine 11, a first generator 12, a steam turbine 13, and a second generator 14; the recovery and recycling unit 2 includes a waste heat steam generator 21 and a waste heat recovery unit 22.

[0052] Among them, the gas turbine 11 is connected to the first generator 12 at one end and to the waste heat steam generator 21 via the exhaust pipe at the other end; the steam turbine 13 is connected to the waste heat steam generator 21 at one end and to the second generator 14 at the other end.

[0053] The waste heat recovery unit 2 also includes a main body, with the waste heat steam generator 21 and the waste heat recovery unit 22 located at least partially within the main body. Integrating the waste heat recovery unit 22 downstream of the waste heat steam generator 21 and into a single housing, treating it as a single unit, effectively reduces the need for connecting flues, supporting structures, and insulation materials between two independent units, thus lowering the footprint of the waste heat recovery unit 2 on the FPSO. Furthermore, since all heat exchange processes are completed within a single insulated housing, heat loss from connecting pipes between independent units is avoided, resulting in higher waste heat recovery efficiency.

[0054] To ensure the long-term, stable and efficient operation of this combined heat and power system under the superconducting FPSO process environment.

[0055] In one embodiment, the control device 4 includes: a data acquisition module (not shown) for real-time acquisition of operating parameters of the turbine generator 1, the recycling device 2, and the heater 3; an early warning module (not shown) connected in communication with the data acquisition module for generating an early warning signal when abnormal operating parameters are detected; and a display module (not shown) for displaying the operating parameters and the early warning signal.

[0056] Furthermore, to further enhance the automation level of system control, regulating valves (not shown) are installed in the turbine generator unit 1 and the recycling unit 2.

[0057] In this embodiment, the control device 4 is configured to collect and analyze the operating parameters of the combined heat and power system in real time during operation. When the real-time data deviates from a preset threshold, an early warning module is activated to alert maintenance personnel to potential degradation.

[0058] For example, operating parameters include, but are not limited to, the exhaust gas temperature and flow rate of gas turbine 11, the extraction / exhaust steam pressure of steam turbine 13, the temperature and pressure of the heat transfer medium before and after waste heat recovery unit 22, and the temperature of the heat transfer medium at the outlet of heater 3. The control device and regulating valves are linked to form a closed-loop control system. When an anomaly is detected, the control device 4 can automatically generate maintenance suggestions or operating instructions based on the warning signal and send them to the display module to assist operators in making quick decisions. Intervention can also be carried out through actuators such as regulating valves to attempt to restore the system state to the normal range.

[0059] In one embodiment, the combined heat and power cycle system further includes a condenser 5. For example... Figure 1 As shown, one end of the condenser 5 is connected to the heater 3, and the other end is connected to the waste heat steam generator 21.

[0060] The following section combines specific applications. Figure 1 , Figure 2 The working principle of the combined heat and power system provided in this application will be further explained as follows:

[0061] In this embodiment, the gas turbine 11 burns oil and gas fuel, which drives the first generator 12 to generate approximately 80% of the total power (i.e., the first power), supplying the FPSO. The exhaust gas at a first temperature (450°C-550°C) enters the exhaust duct and passes through a waste heat steam generator 21, heating the water flowing through it into superheated high-pressure steam. This superheated high-pressure steam then enters the steam turbine 13, which drives the second generator 14 to generate approximately 20% of the total power (i.e., the second power), supplying the FPSO. The first and second power are combined, and the total system output power remains stable within the range of 160MW–170MW, sufficient to meet the power requirements of an ultra-large FPSO.

[0062] After the flue gas at the first temperature leaves the waste heat steam generator 21, its temperature decreases to the second temperature (200℃-300℃). To further and effectively utilize this large amount of waste heat, the flue gas at the second temperature then enters the waste heat recovery unit 22, where the heat transfer medium flowing through it is preheated from its initial temperature to a certain temperature.

[0063] On the other hand, the steam discharged from the turbine 13 after doing work is divided into two paths: one part is led to the heater 3 to finally heat the preheated heat medium to reach the preset temperature required by the process; the other part enters the condenser 5, and after condensation and necessary treatment, it is sent back to the waste heat steam generator 21 to start a new cycle, thereby realizing the efficient recovery and reuse of the working medium.

[0064] During the operation of this combined heat and power (CHP) system, the control module performs full-process monitoring and regulation. For example, when the process heat demand of the FPSO increases, the control device can automatically increase the opening of the regulating valve on the steam pipeline to supplement heat, ensure the stability of the heat transfer medium output temperature, and thus ensure the continuity and reliability of the FPSO production process.

[0065] In the above embodiments, preheating significantly reduces the heat required for the heat transfer medium during subsequent heating. Through system optimization, the power required for subsequent steam heating is significantly reduced, achieving a usable heat transfer medium power of at least 130MW, higher than conventional designs. This successfully overcomes the limitation of combined cycle systems in related technologies, which are only applicable to small and medium-sized FPSOs, extending the combined cycle system technology to ultra-large FPSOs. It meets the high power load requirements of 160MW–170MW for ultra-large FPSOs, as well as their massive process heat transfer medium heating needs. Simultaneously, by deeply exploring the waste heat potential of flue gas and steam, the system significantly improves overall energy utilization efficiency, reduces carbon emissions, and actively responds to the requirements of green, low-carbon, and sustainable development. This lays the foundation for solving the energy supply challenges of ultra-large FPSOs.

[0066] In some embodiments, this application provides a floating production storage and offloading (FPSO) vessel employing the combined heat and power (CHP) system described in any of the above embodiments. Since the FPSO vessels of the above embodiments are based on the same concept, the FPSO vessel employing this CHP system possesses all the advantages of the CHP system, including high-efficiency power generation, deep waste heat recovery, stable process heating capacity, and excellent carbon reduction performance, which will not be elaborated further here.

[0067] The combined heat and power (CHP) system for offshore floating production storage and offloading (FPSO) vessels provided in this application takes into account the different temperature requirements of the waste heat steam generator (HRSG) and waste heat recovery unit (WHRU). This application connects the HRSG and WHRU in series on the exhaust pipe of the gas turbine (GTG). The waste heat of the flue gas leaving the HRSG is used to further heat the heat transfer medium in the WHRU. Through the cascade utilization of flue gas heat energy, the full extraction and conversion of flue gas heat energy in different temperature zones is effectively guaranteed, the overall energy utilization efficiency is improved, the power demand of ultra-large FPSOs is met, the shortcomings of the process heat transfer medium heating capacity in conventional combined cycle systems are made up for, and the system actively responds to the requirements of green, low-carbon and sustainable development during operation, providing a reliable technical path for improving energy efficiency and reducing carbon emissions in offshore oil and gas production.

[0068] In the description of this specification, references to terms such as "some embodiments," "other embodiments," and "ideal embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0069] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features of the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0070] The embodiments described above are merely examples of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application.

Claims

1. A combined heat and power (CHP) system, characterized in that, include: A turbine generator unit is used to drive a generator to supply electricity via fuel and steam, and to discharge flue gas at a first temperature generated during the combustion of said fuel through a flue pipe; A recycling device is installed on the flue gas duct, including a waste heat steam generator and a waste heat recovery unit; the waste heat steam generator uses the first temperature flue gas as a heat source to generate steam, which is then supplied to the turbine power generation unit and discharged through the flue gas duct at the second temperature; the waste heat recovery unit uses the second temperature flue gas as a heat source to preheat the heat medium flowing through the waste heat recovery unit. A heater, connected to the waste heat recovery unit, is used to receive and pass through the steam discharged from the turbine power generation unit, and heat the heat medium to a preset temperature.

2. The combined heat and power system according to claim 1, characterized in that, A marine power generation unit, comprising: A gas turbine is connected at one end to a first generator and at the other end to a waste heat steam generator via the exhaust pipe, for burning the fuel to drive the first generator to generate first electricity and discharge flue gas at the first temperature; A steam turbine is connected at one end to the waste heat steam generator and at the other end to a second generator, which is used to drive the second generator to generate second electricity and discharge the steam through a pipeline; The total power output of the first and second power sources ranges from 160MW to 170MW.

3. The combined heat and power system according to claim 2, characterized in that, The gas turbine generates a first-temperature flue gas with a temperature range of 450℃-550℃, and discharges a second-temperature flue gas with a temperature range of 200℃-300℃.

4. The combined heat and power system according to claim 1, characterized in that, The heater requires less power than the original power. The raw power is used to characterize the power required by the heater to heat the heat medium to a preset temperature when the steam is not applied and the heat medium is not preheated; The original power is not less than 130MW.

5. The combined heat and power system according to any one of claims 1-4, characterized in that, include: A condenser, one end of which is connected to the heater and the other end of which is connected to the waste heat steam generator, is used to receive the steam and cool and recirculate it.

6. The combined heat and power system according to any one of claims 1-4, characterized in that, The combined cycle system also includes: A control device, connected to the turbine generator, the recovery and circulation device, and the heater, is used to control the turbine generator, the recovery and circulation device, and the heater to perform corresponding operations upon receiving a demand command for the power load or heat load of the offshore floating platform.

7. The combined heat and power system according to any one of claims 1-4, characterized in that, The recycling device also includes a main body; The waste heat steam generator and the waste heat recovery unit are at least partially located within the main body.

8. The combined heat and power system according to claim 6, characterized in that, The control device includes: The data acquisition module is used to collect the operating parameters of the turbine power generation unit, the recycling unit and the heater in real time; The early warning module is communicatively connected to the data acquisition module and is used to generate an early warning signal when abnormal operating parameters are detected. The display module is used to display the operating parameters and the warning signals.

9. The combined heat and power system according to claim 8, characterized in that, The combined cycle system also includes: A regulating valve is located within the recycling device and the turbine power generation device; The control device is used to control the opening degree of the regulating valve upon receiving a demand command for the electrical or thermal load of the offshore floating platform.

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