Offshore wind power and methanol synthesis system meeting peak load

Abstract

The invention discloses an offshore wind power and methanol synthesis system meeting a peak load, and relates to the technical field of offshore wind power. Comprising an offshore wind generating set which generates electricity by utilizing offshore wind energy and transmits the generated electric energy to an electrical control system for scheduling; the transport ship transports the carbon dioxide captured from the land to the offshore platform, the carbon dioxide is transported to the methanol synthesis module through a transport pipeline to serve as a production raw material, and methanol is prepared through carbon dioxide hydrogenation; the electrical control system is used for receiving electric energy from the offshore wind generating set or the methanol generator, grid-connected to supply power to a power grid when the power grid load is peak, and supplying the electric energy to the seawater desalination module, the water electrolysis hydrogen production module and the like at other moments; the seawater desalination module uses a reverse osmosis membrane method, and seawater enters a reverse osmosis membrane through pressurization of a high-pressure pump so as to realize seawater desalination. According to the invention, the energy consumption process of offshore wind power generation and methanol synthesis is combined, so that high-efficiency conversion and utilization of wind energy with volatility and intermittency are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of offshore wind power, and in particular to an offshore wind power and methanol synthesis system that meets peak load requirements. Background Art

[0002] Offshore wind power has become a hot development direction in the field of renewable energy due to its abundant resources, no land occupation, and low environmental impact. However, affected by the characteristics of wind resources, wind power generation has the characteristics of volatility, randomness, and intermittency. In particular, offshore wind power has the characteristics of anti-peak regulation, which means that the wind power output and load output curves are mostly opposite. Large-scale wind power grid connection will significantly increase the peak-to-valley difference of the system, affecting the safe and stable operation of the power grid. The regulation margin of conventional wind turbines is relatively limited. It is difficult to meet the system regulation capacity requirements at peak or valley loads only through coordination between conventional units, which may cause wind abandonment to ensure the active balance of the system, resulting in a waste of wind energy.

[0003] In this context, it is considered to combine offshore wind power generation with other energy-consuming processes to realize the conversion and utilization of wind energy. Methanol synthesis is an important chemical process. Through the electricity generated by offshore wind power, water is electrolyzed to produce hydrogen, and then the produced hydrogen is synthesized with carbon dioxide into methanol. It can convert renewable energy into storable and transportable liquid fuel, realize the long-term storage and utilization of wind energy, and provide an effective energy conversion method for offshore wind power. In addition, the combination of offshore wind power and methanol synthesis system can effectively solve the problems of wind energy volatility and intermittent power generation in offshore wind power, and provide power support for peak loads of the power grid, which has high engineering application value and market potential.

[0004] Although there are some studies involving the combination of offshore wind power with other energy-consuming processes, the existing technologies focus on the use of wind power to produce hydrogen through water electrolysis, and the conversion and utilization of wind energy is achieved through the storage and transportation of hydrogen energy. The coupling of offshore wind power and methanol synthesis technology is still in its early stages.

[0005] Wang Jingyi et al. proposed a hydrogen-ammonia-alcohol cogeneration system and method based on offshore wind power generation (publication number: CN114790552A). The system converts offshore wind power into green ammonia and natural gas into methanol through offshore wind farms, natural gas platforms and offshore cogeneration energy platforms. The liquid ammonia and methanol are then transported back to the land load center by ship for use or to provide fuel for sailing ships. However, the system cannot directly provide power support when the grid load is peak.

[0006] Li Zaipeng and others proposed a hydrogen and ammonia production platform using offshore wind farms (publication number: CN218559199U). A production process deck was set up on the main deck of a barge-type floating platform. The platform power grid was connected to the surrounding offshore wind power grid through cables to supply power for the preparation of liquid ammonia and hydrogen. However, the storage of liquid ammonia requires a low-temperature storage environment with good insulation properties, which will increase energy consumption. Hydrogen also has problems of low storage density and difficulty in transportation at room temperature.

[0007] Luo Chengyuan et al. proposed a method of multi-energy complementation of power sources and source-load-storage interaction (publication number: CN114400685A), using unstable electricity such as solar energy and wind energy to electrolyze water to produce hydrogen, hydrogen and carbon dioxide to produce methanol, methanol and biomass energy and oil to make liquid fuel, and then generate electricity through boiler generators to achieve power complementation. However, this method is for wind power and photovoltaic power on the ground, and the construction of the plant requires a large amount of land resources. At the same time, there will be carbon dioxide emissions during the methanol fuel power generation process.

[0008] In summary, there is still a lack of effective solutions to combine methanol production with offshore wind power generation to meet the peak load of the power grid, which to some extent limits the efficient conversion and utilization of offshore wind power and the diversified development of green methanol production. Summary of the invention

[0009] In view of the deficiencies in the above-mentioned prior art, the present invention provides an offshore wind power and methanol synthesis system that meets peak loads. The present invention generates electricity through offshore wind turbines, connects wind power to the grid for peak regulation when the grid load is peak, and disconnects the grid during non-load peaks. The electric energy generated by the wind turbines is used to electrolyze water to produce hydrogen, and the obtained hydrogen is synthesized into methanol with captured carbon dioxide. The prepared methanol can be supplied to load centers such as land for use, and can also provide power support through a methanol power generation module when the grid load is peak, thereby improving the stability of the grid power supply.

[0010] The specific technical solutions are as follows:

[0011] An offshore wind power and methanol synthesis system that meets peak loads, comprising:

[0012] Offshore wind turbines use offshore wind energy to generate electricity and transmit the generated electricity to the electrical control system for dispatch;

[0013] The transport ship will transport the carbon dioxide captured from land to the offshore platform, and then transport it to the methanol synthesis module through the transport pipeline as a production raw material, and produce methanol through the hydrogenation of carbon dioxide;

[0014] The electrical control system receives electricity from offshore wind turbines and methanol generators and distributes the electricity. When the grid load peaks, the electricity generated by the wind turbines is directly connected to the grid to provide sufficient power support for the grid. At the same time, the methanol power generation module is started to supplement the grid power by burning the methanol stored on the offshore platform or generating electricity through fuel cells to cope with the peak load of the grid. During non-peak load periods, the excess electricity generated by the offshore wind turbines is preferentially used for energy-intensive chemical processes.

[0015] The water electrolysis hydrogen production module receives the electric energy distributed by the electrical control system and uses it to electrolyze water to produce hydrogen, and then transports the hydrogen to the methanol synthesis module through a transportation pipeline as a production raw material;

[0016] The methanol synthesis module produces methanol by synthesizing the hydrogen produced by the water electrolysis hydrogen production module with the carbon dioxide transported by the transport ship;

[0017] The methanol distillation module receives the crude methanol produced by the methanol synthesis module, collects high-purity methanol products through heating, gas-liquid separation, distillation in a distillation tower, and condensation processes, and transports the collected products to land load centers via transport ships; and

[0018] The methanol power generation module uses high-purity methanol obtained after distillation and directly burns it in a gas turbine to generate electricity.

[0019] Furthermore, in the above scheme, when wind power is insufficient, the methanol power generation module uses the stored methanol to generate electricity.

[0020] Furthermore, in the above scheme, during the non-peak load period of the power grid, the electrical control system preferentially distributes the electric energy of the wind turbine to the seawater desalination module, the water electrolysis hydrogen production module, the methanol synthesis module and the methanol distillation module.

[0021] Furthermore, in the above scheme, during the peak load period of the power grid, the methanol distillation module transports methanol to the methanol power generation module for power generation to provide power support for the power grid.

[0022] In the above scheme, the methanol power generation module generates electricity by means of electrochemical conversion via a methanol fuel cell.

[0023] The above scheme further includes a carbon dioxide storage tank and a carbon capture device. The carbon dioxide storage tank is used to store the carbon dioxide transported by the carbon dioxide transport ship and is used to provide the methanol synthesis module; the methanol power generation module is a methanol direct-fired generator set, and the carbon capture device is used to collect the carbon dioxide generated by the combustion of the methanol direct-fired generator set, and transport the carbon dioxide to the methanol synthesis module through a transportation pipeline. The waste heat generated during the methanol direct-fired power generation process is transported to the methanol synthesis module.

[0024] The above scheme further includes a hydrogen storage tank and a phosphoric acid type hydrogen fuel cell. The hydrogen storage tank is used to receive hydrogen produced by the water electrolysis hydrogen production module to supply the phosphoric acid type hydrogen fuel cell for power generation. The phosphoric acid type hydrogen fuel cell is connected to an electrical control system; the phosphoric acid type hydrogen fuel cell is used to generate electricity when wind power does not meet the peak load of the power grid.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention combines offshore wind power generation with the energy-consuming process of methanol synthesis to achieve efficient conversion and utilization of fluctuating and intermittent wind energy. The long-term storage of wind energy is achieved by synthesizing methanol from hydrogen and carbon dioxide after hydrogen is produced by electrolysis of water. This can provide power support when the power grid load is peak, thereby ensuring the stable operation of the power grid.

[0027] The electric energy used by the offshore synthesis platform in the present invention comes from offshore wind power generation. There is also very little greenhouse gas emission during the methanol synthesis process, and it has green and low-carbon attributes. At the same time, one of the raw materials for methanol production is carbon dioxide captured from carbon emission sources, which has a carbon fixation effect and can promote the realization of carbon neutrality goals.

[0028] The present invention can ensure the stability of power supply in the power grid. Traditional large-scale offshore wind power grid connection may need to abandon wind to ensure the active power balance of the system due to its anti-peak regulation characteristics, resulting in a waste of wind energy. The power generated by the offshore wind turbines of the present invention is only connected to the grid when the power grid load is peak, and the power is not connected to the grid at other times, and is only used for the methanol production process on the platform, which effectively avoids the impact of the volatility and intermittency of offshore wind power on the power grid and improves the utilization rate of renewable energy. In addition, when wind energy is insufficient to provide power support for peak loads, the methanol power generation module can also be used to make up for the problem of insufficient wind power, greatly improving the stability of power supply in the power grid.

[0029] The present invention has high economic efficiency. Methanol is liquid at normal temperature and pressure, has high storage density, good safety, and is easy to transport. The produced methanol can be sold to obtain higher economic efficiency. At the same time, the offshore platform can simultaneously undertake the wind power operation and maintenance functions and the methanol synthesis functions, reducing the land cost. In addition, the transport ship can transport carbon dioxide from land to the offshore platform, and then transport the produced methanol from the offshore platform to land, avoiding empty ships, which can improve transportation efficiency and reduce transportation costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a diagram of the process of realizing the structure of the present invention;

[0031] Figure 2 is a schematic diagram of an embodiment of the present invention;

[0032] Figure 3 It is a schematic diagram of another embodiment of the present invention. DETAILED DESCRIPTION

[0033] The following is a further detailed description of the embodiments of the invention in conjunction with the accompanying drawings to make the objectives, technical solutions and technical effects of the invention more clearly presented.

[0034] The implementation process of the present invention is as follows Figure 1 As shown: an offshore wind power platform and methanol synthesis system that meets peak loads, including an offshore wind turbine, an offshore methanol production platform, and a transport ship; wherein the offshore methanol synthesis platform includes an electrical control system, a seawater desalination module, a carbon dioxide storage tank, a water electrolysis hydrogen production module, a methanol synthesis module, a methanol distillation module, a methanol storage tank, and a methanol power generation module.

[0035] The connection relationship and functions of each component are as follows:

[0036] Offshore wind turbines: use offshore wind energy to generate electricity and transmit the generated electricity to the electrical control system for scheduling.

[0037] The transport ship will transport the carbon dioxide captured from the land to the offshore platform, and then transport it to the methanol synthesis module through the transport pipeline as a production raw material, and produce methanol through the hydrogenation of carbon dioxide. After the carbon dioxide is transported, the produced methanol can be transported from the offshore platform to the land for use in the load center.

[0038] The electrical control system receives electricity from offshore wind turbines or methanol generators. As the core of power distribution, it has functions such as voltage transformation, rectification, and regulation. It can be connected to the grid to supply power to the grid when the grid load is peak, and supply electricity to the seawater desalination module, water electrolysis hydrogen production module, methanol synthesis module, and methanol distillation module to prepare methanol at other times.

[0039] Specifically, the electrical control system, as the core control and dispatching equipment of the entire system, receives electricity from offshore wind turbines and methanol generators, and distributes the electricity reasonably. When the grid load peaks, the system directly integrates the electricity generated by wind turbines into the grid to provide sufficient power support for the grid. At the same time, the methanol power generation module is also started to supplement the grid power by burning or generating electricity from fuel cells with methanol stored on the offshore platform to cope with the peak load of the grid. During non-peak load periods, the electrical control system will give priority to the energy-intensive chemical processes inside the platform, such as the operation of seawater desalination modules, water electrolysis hydrogen production modules, methanol synthesis modules, and methanol distillation modules, based on actual conditions. Through this dispatching mechanism, the electrical control system not only realizes the efficient conversion and utilization of wind power energy, but also achieves maximum reduction of energy waste in the case of frequent load fluctuations by precisely controlling the combination of wind power and methanol production processes, thereby optimizing the balance of grid load.

[0040] The seawater desalination module uses the reverse osmosis membrane method and pressurizes seawater into the reverse osmosis membrane through a high-pressure pump. The technical equipment has a relatively simple structure and is easy to maintain and manage. When offshore wind energy is abundant, it can stably output a large amount of fresh water and is suitable for large water environments such as offshore wind farms.

[0041] The water electrolysis hydrogen production module receives the electric energy distributed by the electrical control system and uses it to electrolyze water to produce hydrogen, and then transports the hydrogen to the methanol synthesis module through a transportation pipeline as a production raw material.

[0042] The methanol synthesis module obtains carbon dioxide and hydrogen raw materials from the transportation pipeline, sends the carbon dioxide and hydrogen into the catalytic reactor, and synthesizes methanol under the catalysis of the catalyst. The specific chemical reaction is that the produced methanol is then transported to the methanol distillation module through the transportation pipeline.

[0043] Among them, the methanol synthesis module is an important part of the system that converts wind power into chemical energy. Its function is to synthesize the hydrogen produced by the water electrolysis hydrogen production module with the carbon dioxide transported by the transport ship to produce methanol. The module obtains hydrogen and carbon dioxide from the transportation pipeline, sends the two into a high-efficiency catalytic reactor, and synthesizes methanol under the catalysis of the catalyst. In addition, by combining the intermittent characteristics of wind power, the methanol synthesis module can flexibly operate efficiently during periods of excess wind power, converting wind energy into storable liquid fuel methanol, achieving the effect of energy storage and peak shaving. The final synthesized methanol is sent to the methanol distillation module through a dedicated transportation pipeline for further purification.

[0044] The methanol distillation module receives the crude methanol produced by the methanol synthesis module, collects high-purity methanol products through processes such as heating, gas-liquid separation, distillation in a distillation tower, and condensation, and transports the collected products to land load centers via transport ships, or transports them to the methanol power generation module to generate electricity to provide power support for the grid when the grid load is peak.

[0045] The methanol power generation module uses high-purity methanol obtained after distillation to directly burn it in a gas turbine to generate electricity, or it can generate electricity through electrochemical conversion through a methanol fuel cell.

[0046] The overall working principle of the system is as follows: First, the offshore wind turbines provide basic power support for the offshore methanol synthesis platform by converting wind energy into electrical energy. The electrical control system is responsible for the intelligent dispatch of electrical energy in the entire system and flexibly distributes it according to the load of the power grid. When the power grid load is at a peak period, the system's primary task is to integrate the power of the wind turbines into the power grid to provide power support. At the same time, the methanol power generation module will also be started to ensure that sufficient power support can be obtained during the peak period of power grid demand. In the case of insufficient wind power, the methanol power generation module uses the previously produced and stored methanol to generate electricity, thereby improving the reliability and response speed of the system. During non-peak load periods, the system prioritizes the power of the wind turbines to the internal chemical production process, including the seawater desalination module, the water electrolysis hydrogen production module, the methanol synthesis module, and the methanol distillation module. These modules work together to convert wind energy into liquid methanol and store it, providing an effective long-term energy storage solution. At the same time, by controlling the coordinated work of each module, the system not only achieves the effective use of energy, but also significantly improves the economy and reliability of the wind power system. The high-purity methanol produced can be delivered to land load centers by transport ships for use, or it can be converted back into electricity through methanol power generation modules during peak load periods, thus flexibly responding to changes in grid load demand.

[0047] Example 1

[0048] In the methanol power generation module of this technical solution, the methanol power generation mode is optional methanol direct combustion power generation and methanol fuel cell power generation. When methanol direct combustion power generation is selected, the system of this embodiment is as follows Figure 2As shown: the technical solution includes an offshore wind turbine, an offshore methanol production platform, and a transport ship; wherein the offshore methanol synthesis platform includes an electrical control system, a seawater desalination module, a carbon dioxide storage tank, a water electrolysis hydrogen production module, a methanol synthesis module, a methanol distillation module, a methanol storage tank, and a methanol direct-fired generator set. Compared with the initial setting, the above part can add a carbon capture device after the methanol direct-fired generator set to collect the carbon dioxide produced by combustion, and then transport the carbon dioxide to the methanol synthesis module through a transport pipeline. The waste heat generated during the methanol direct-fired power generation process can also be transported to the methanol synthesis module, forming a recycling of resources and improving the operating efficiency of the system.

[0049] Example 2

[0050] In the technical solution of Example 2, when the electric energy of offshore wind power cannot meet the peak load of the power grid, the power generation module that provides additional power support adopts a phosphoric acid type hydrogen fuel cell.

[0051] The methanol power generation module in the initial scheme is replaced, and the system of this embodiment is as follows Figure 3 As shown: the system includes an offshore wind turbine, an offshore methanol synthesis platform, and a transport ship; wherein the offshore methanol synthesis platform includes an electrical control system, a seawater desalination module, a carbon dioxide storage tank, a water electrolysis hydrogen production module, a hydrogen storage tank, a phosphoric acid type hydrogen fuel cell, a methanol synthesis module, a methanol distillation module, and a methanol storage tank. The hydrogen storage tank receives the hydrogen produced by the water electrolysis hydrogen production module and supplies it to the phosphoric acid type hydrogen fuel cell for power generation when needed.

[0052] Since hydrogen fuel cells only need to generate electricity when wind power is insufficient to meet the peak load of the power grid, the corresponding hydrogen storage tank capacity can be smaller. Compared with the initial solution, this replacement technology does not need to synthesize methanol first and then generate electricity through methanol. Instead, it directly uses the hydrogen produced by the water electrolysis hydrogen production module, reducing the energy conversion steps and having a higher energy conversion efficiency, but the storage density of hydrogen is lower than that of liquid methanol.

[0053] The above description is only a preferred feasible embodiment of the present invention and is not intended to limit the scope of the patent application of the present invention. All equivalent changes, equivalent substitutions or modified changes performed within the technical spirit and principles suggested by the present invention should be included in the scope of patent protection covered by the present invention.

Claims

1. An offshore wind power and methanol synthesis system that meets peak loads, characterized in that: include: Offshore wind turbines use offshore wind energy to generate electricity and transmit the generated electricity to the electrical control system for dispatch; The transport ship will transport the carbon dioxide captured from land to the offshore platform, and then transport it to the methanol synthesis module through the transport pipeline as a production raw material, and produce methanol through the hydrogenation of carbon dioxide; The electrical control system receives electricity from offshore wind turbines and methanol generators and distributes the electricity. When the grid load peaks, the electricity generated by the wind turbines is directly connected to the grid to provide sufficient power support for the grid. At the same time, the methanol power generation module is started to supplement the grid power by burning the methanol stored on the offshore platform or generating electricity through fuel cells to cope with the peak load of the grid. During non-peak load periods, the excess electricity generated by the offshore wind turbines is preferentially used for energy-intensive chemical processes. The water electrolysis hydrogen production module receives the electric energy distributed by the electrical control system and uses it to electrolyze water to produce hydrogen, and then transports the hydrogen to the methanol synthesis module through a transportation pipeline as a production raw material; The methanol synthesis module produces methanol by synthesizing the hydrogen produced by the water electrolysis hydrogen production module with the carbon dioxide transported by the transport ship; The methanol distillation module receives the crude methanol produced by the methanol synthesis module, collects high-purity methanol products through heating, gas-liquid separation, distillation in a distillation tower, and condensation processes, and transports the collected products to land load centers via transport ships; and The methanol power generation module uses high-purity methanol obtained after distillation and directly burns it in a gas turbine to generate electricity.

2. The offshore wind power and methanol synthesis system that meets peak load requirements according to claim 1, characterized in that: When wind power is insufficient, the methanol power generation module uses stored methanol to generate electricity.

3. The offshore wind power and methanol synthesis system that meets peak load requirements according to claim 1, characterized in that: During the non-peak load period of the power grid, the electrical control system will preferentially allocate the electric energy of the wind turbine to the seawater desalination module, the water electrolysis hydrogen production module, the methanol synthesis module and the methanol distillation module.

4. The offshore wind power and methanol synthesis system that meets peak load requirements according to claim 1, characterized in that: During peak load periods of the power grid, the methanol distillation module transports methanol to the methanol power generation module for power generation to provide power support for the power grid.

5. The offshore wind power and methanol synthesis system that meets peak load requirements according to claim 1, characterized in that: The methanol power generation module generates electricity through electrochemical conversion using a methanol fuel cell.

6. The offshore wind power and methanol synthesis system that meets peak load requirements according to claim 1, characterized in that: It also includes a carbon dioxide storage tank and a carbon capture device. The carbon dioxide storage tank is used to store the carbon dioxide transported by the carbon dioxide transport ship and is used to provide a methanol synthesis module. The methanol power generation module is a methanol direct-fired generator set. The carbon capture device is used to collect the carbon dioxide generated by the combustion of the methanol direct-fired generator set and transport the carbon dioxide to the methanol synthesis module through a transportation pipeline. The waste heat generated during the methanol direct-fired power generation process is transported to the methanol synthesis module.

7. The offshore wind power and methanol synthesis system that meets peak load requirements according to claim 1, characterized in that: It also includes a hydrogen storage tank and a phosphoric acid type hydrogen fuel cell. The hydrogen storage tank is used to receive the hydrogen produced by the water electrolysis hydrogen production module to supply the phosphoric acid type hydrogen fuel cell for power generation. The phosphoric acid type hydrogen fuel cell is connected to the electrical control system; the phosphoric acid type hydrogen fuel cell is used to generate electricity when wind power does not meet the peak load of the power grid.

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