Deep sea floating type ammonia production and storage system and working method

Abstract

The invention discloses a deep sea floating type ammonia production and storage system and method, and the system comprises an offshore floating type ammonia production ship which is located on the sea surface and is used for producing liquid ammonia; the wind power generation device is positioned above the sea surface and is used for supplying energy required for producing liquid ammonia to the offshore floating type ammonia production ship; the underwater flexible liquid ammonia storage device is located below the sea surface and used for storing liquid ammonia produced by the offshore floating type ammonia production ship, and the water pressure provided by the seawater depth of the installation position of the underwater flexible liquid ammonia storage device is larger than the ammonia saturated vapor pressure corresponding to the seawater temperature of the installation position; liquid ammonia produced by the offshore floating ammonia production ship is conveyed into the underwater flexible liquid ammonia storage device through a pipeline to be stored; according to the offshore floating type production ammonia storage ship containing the underwater flexible liquid storage device, the deepwater pressure and the temperature environment are fully utilized, the flexible non-metal bag is adopted as the liquid ammonia storage device, and therefore the manufacturing cost of the FPSO under the same ammonia production capacity is lower, and the liquid ammonia storage cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid ammonia production and storage, and in particular to a deep-sea floating ammonia production and storage system and a working method. Background Art

[0002] The statements herein merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] As an extension of the hydrogen industry, liquid ammonia is considered to be a new low-carbon fuel of the future. Deep sea wind power resources are abundant, but the cost of transmitting electricity to land is high and the loss is large; ammonia, as an important chemical raw material and clean fuel, has the characteristics of high liquefaction temperature and low liquefaction pressure. It is an excellent green energy carrier and is suitable for large-capacity storage and transportation at sea.

[0004] At present, international organizations have designed floating ammonia production and storage vessels (NH3 FPSO), which obtain electricity from wind energy generated by offshore wind farms. This electricity is used to drive electrolysis devices to electrolyze seawater to produce hydrogen, which is the main raw material for producing green ammonia. Under high temperature and high pressure conditions, the hydrogen produced by electrolysis is mixed with nitrogen to produce liquid ammonia through the "Haber process". NH3 FPSO will be permanently moored and "stationed" in offshore wind farms; it can also be moved to other wind farms when necessary. The produced ammonia will be transmitted from the FPSO to other ammonia transport ships through pipelines to complete the transfer.

[0005] However, the ammonia storage modules of current NH3 FPSOs are all installed inside the cabin, which may cause the following problems:

[0006] (1) Liquid ammonia is stored in FPSO cabins at high pressure or low temperature, which takes up a lot of cabin space and has high storage costs;

[0007] (2) Under the same circumstances, the liquid storage space limits the ammonia production scale in NH3 FPSO. Summary of the invention

[0008] The purpose of the present invention is to provide a deep-sea floating production and storage ammonia system, which can make full use of seawater pressure and a stable temperature environment to reduce the storage cost of liquid ammonia; without the need to set up a large-volume liquid ammonia storage tank, a higher-power production system can be arranged in a limited space.

[0009] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0010] In a first aspect, an embodiment of the present invention provides a deep sea floating production and storage ammonia system, comprising:

[0011] Offshore floating ammonia production vessels, located above the sea surface, are used to produce liquid ammonia;

[0012] A wind power plant located above the sea surface is used to generate the energy required to produce liquid ammonia for an offshore floating ammonia production vessel;

[0013] An underwater flexible liquid ammonia storage device, located below the sea surface, for storing liquid ammonia produced by an offshore floating ammonia production vessel, wherein the water pressure provided by the seawater depth at the installation location of the underwater flexible liquid ammonia storage device is greater than the ammonia saturated vapor pressure corresponding to the seawater temperature at the installation location;

[0014] The liquid ammonia produced by the offshore floating ammonia production vessel is transported to an underwater flexible liquid ammonia storage device through a pipeline for storage.

[0015] As a further technical solution, the underwater flexible liquid ammonia storage device is provided with a liquid ammonia inlet and a liquid ammonia outlet, the liquid ammonia inlet is connected to an inlet pipe, and the liquid ammonia outlet is connected to an outlet pipe.

[0016] As a further technical solution, the inlet pipeline is connected to the surface liquid ammonia export pipeline and the ammonia supply pipeline of the offshore floating ammonia production vessel through a riser, and the lower end of the riser is also connected to the outlet pipeline.

[0017] As a further technical solution, the external transmission pipeline is connected to the ammonia supply pipeline, and an external transmission valve is provided on the external transmission pipeline.

[0018] As a further technical solution, a regulating valve with throttling and pressure reducing function is arranged on the inlet pipeline, and a booster pump and a check valve are arranged on the outlet pipeline, and the check valve is located at the outlet of the booster pump.

[0019] As a further technical solution, the booster pump is arranged near the liquid ammonia outlet of the underwater flexible liquid ammonia storage device and its height does not exceed the highest point of the non-metallic flexible bag.

[0020] As a further technical solution, the underwater flexible liquid ammonia storage device adopts a non-metallic flexible bag, the bottom of which is connected to an anchor chain, and the end of the anchor chain is anchored to the seabed.

[0021] As a further technical solution, the wind power generation device is provided to the offshore floating ammonia production vessel through a power transmission system.

[0022] In a second aspect of the present invention, there is provided a method for operating a deep sea floating production and storage ammonia system, comprising the following steps:

[0023] The wind power generation device uses wind energy to generate electricity, and the generated electricity is transmitted to the offshore floating ammonia production vessel through the power transmission system. The offshore floating ammonia production vessel produces liquid ammonia, and the generated liquid ammonia is injected into the underwater flexible liquid ammonia storage device through a pipeline for storage. The water pressure provided by the seawater depth at the installation location of the underwater flexible liquid ammonia storage device is greater than the ammonia saturated vapor pressure corresponding to the seawater temperature at the installation location, so that the ammonia is always stored in a liquid state.

[0024] As a further technical solution, when liquid ammonia production and external transmission are not required, the external transmission valve is closed, and the power equipment on the offshore floating ammonia production ship controls the ammonia pipeline pressure to be above the ammonia saturated vapor pressure corresponding to the transmission temperature, and the liquid ammonia is injected into the underwater flexible liquid ammonia storage device through the riser and the regulating valve along the ammonia supply pipeline. At this time, the valve throttling needs to be adjusted to reduce the pressure of the liquid ammonia entering the flexible liquid ammonia storage device to the water pressure at the water depth where the flexible liquid ammonia storage device is located; at the same time, because the lower end of the riser is connected, the pipeline downstream of the pump outlet check valve can maintain the internal pressure above the ammonia saturated vapor pressure when the transmission is stopped, thereby keeping the internal ammonia in the liquid phase;

[0025] When liquid ammonia needs to be produced and exported, the pressure pump and the export valve are turned on, and the regulating valve is closed. The liquid ammonia in the flexible liquid ammonia storage device passes through the pressure pump and the one-way valve and enters the export pipeline through the riser. The liquid ammonia from the offshore floating ammonia production ship directly enters the export pipeline through the ammonia supply pipeline and is then exported to the surface ship.

[0026] The beneficial effects of the above embodiments of the present invention are as follows:

[0027] (1) Based on the physical properties of ammonia, the present invention proposes an offshore floating production and storage vessel with an underwater flexible liquid storage device, that is, making full use of the deep water pressure and temperature environment, and using a flexible non-metallic bladder as a liquid ammonia storage device, thereby making the manufacturing cost of FPSO lower under the same ammonia production capacity and reducing the liquid ammonia storage cost.

[0028] (2) The liquid ammonia produced by the offshore floating ammonia production vessel of the present invention can be stored by an underwater flexible liquid ammonia storage device. During the storage process, the seawater pressure and the stable temperature environment are fully utilized to reduce the storage cost of the liquid ammonia. There is no need to set up a large-volume liquid ammonia storage tank, and a higher-power production system can be arranged in a limited space, or the manufacturing cost of the floating production system can be reduced under the same production power.

[0029] (3) The deep-sea floating production and storage ammonia system provided by the present invention is capable of controlling the opening and closing of valves to ensure that the pressure in the non-metallic liquid storage capsule, inlet pipeline, outlet pipeline and riser is above the saturated vapor pressure of ammonia, by arranging corresponding check valves and regulating valves on the pipelines connecting the offshore floating ammonia production vessel and the underwater flexible liquid ammonia storage device, so as to ensure that ammonia can be stored, injected and produced in a liquid state.

[0030] (4) The working method of the deep-sea floating production and storage ammonia system provided by the present invention controls the depth position of the non-metallic liquid storage capsule so that the internal pressure and the ambient temperature conditions are just the conditions where ammonia is in liquid state. Because ammonia is in gaseous state at normal temperature and pressure, its injection and production pipelines must be operated under pressure. By controlling the valves on the pipelines, the pressure in the pipelines and the non-metallic liquid storage capsules is above the saturated vapor pressure of ammonia, so that ammonia can be stored, injected and produced in liquid state. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0032] Figure 1 It is a schematic diagram of the deep sea floating production and storage system of ammonia of the present invention.

[0033] The schematic diagram is for illustrative purposes only;

[0034] Among them, 1. Sea surface; 2. Wind power generation device; 3. Power transmission system; 4. Offshore floating ammonia production vessel; 5. Ammonia supply pipeline; 6. Riser; 7. Inlet pipeline; 8. Regulating valve; 9. Underwater flexible liquid ammonia storage device; 10. Anchor chain; 11. Pressure pump; 12. Check valve; 13. Export pipeline; 14. External transmission valve; 15. External transmission pipeline. DETAILED DESCRIPTION

[0035] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0036] Example 1

[0037] The technical concept of the present invention is as follows:

[0038] The ocean water depth of 100 meters can provide an absolute pressure of 1.1MPa, which can keep ammonia below 28°C in liquid phase. The water temperature at a depth of 100 meters in most sea areas is below 28°C, which can provide a good temperature environment for liquid ammonia storage. According to the physical properties of ammonia, the present invention proposes an offshore floating production and storage ammonia vessel with an underwater flexible liquid storage device. That is, by making full use of the deep water pressure and temperature environment, a flexible non-metallic bladder is used as a liquid ammonia storage device, so that the manufacturing cost of FPSO is lower under the same ammonia production capacity, and the liquid ammonia storage cost is reduced.

[0039] In a typical embodiment of the present invention, Figure 1As shown, a deep sea floating production and storage ammonia system is provided, comprising:

[0040] An offshore floating ammonia production vessel 4, located above the sea surface 1, for producing liquid ammonia;

[0041] The wind power generation device 2 is located above the sea surface 1 and is used to produce the energy required for liquid ammonia to the offshore floating ammonia production vessel 4;

[0042] The underwater flexible liquid ammonia storage device 9 is located below the sea surface and is used to store liquid ammonia produced by the offshore floating ammonia production vessel. The water pressure provided by the seawater depth at the installation location of the underwater flexible liquid ammonia storage device 9 is greater than the ammonia saturated vapor pressure corresponding to the seawater temperature at the installation location;

[0043] The liquid ammonia produced by the offshore floating ammonia production vessel 4 is transported to the underwater flexible liquid ammonia storage device 9 through a pipeline for storage.

[0044] In this embodiment, the underwater flexible liquid ammonia storage device 9 is provided with a liquid ammonia inlet and a liquid ammonia outlet. The liquid ammonia inlet is connected to the inlet pipe 7 , and the liquid ammonia outlet is connected to the outlet pipe 13 .

[0045] Furthermore, the inlet pipeline 7 is connected to the surface liquid ammonia export pipeline 15 and the ammonia supply pipeline 5 of the offshore floating ammonia production vessel through the riser 6 , and the lower end of the riser 6 is also connected to the outlet pipeline 13 .

[0046] Furthermore, the external transmission pipeline 15 is connected to the ammonia supply pipeline 5 , and an external transmission valve 14 is provided on the external transmission pipeline 15 .

[0047] In this embodiment, a regulating valve 8 with a throttling and pressure reducing function is provided on the inlet pipeline 7, and a booster pump 11 and a check valve 12 are provided on the outlet pipeline 13, and the check valve 12 is located at the outlet of the booster pump 11. The inlet pipeline 7 of the flexible liquid ammonia storage device 9 is provided with a regulating valve 8. Since the ammonia supply pipeline 5 of the offshore floating liquid ammonia production ship contains liquid ammonia, this means that the pressure in the ammonia supply pipeline 5 is higher than the saturated vapor pressure of ammonia. When the liquid ammonia flows downward through the riser 6, the gravitational potential energy of the liquid ammonia is converted into pressure energy, which will cause the pressure of the liquid ammonia in the inlet pipeline 7 to further increase, which may be significantly higher than the pressure in the flexible liquid ammonia storage device 9. If the liquid ammonia directly enters the flexible liquid ammonia storage device 9 without throttling, it may cause damage to the non-metallic capsule. Therefore, it is necessary to reduce the pressure of the liquid ammonia entering the flexible liquid ammonia storage device 9 to the same as the surrounding water pressure through the regulating valve 8.

[0048] Furthermore, the booster pump 11 is arranged at the liquid ammonia outlet close to the underwater flexible liquid ammonia storage device 9 and its height does not exceed the highest point of the non-metallic flexible bag; alternatively, the booster pump 11 is installed inside the underwater flexible liquid ammonia storage device 9 to avoid the problem of excessive upward flow height before entering the booster pump 11 for pressurization during liquid ammonia production, thereby causing the pump inlet pressure to be too low and possible gasification of liquid ammonia in the inlet pipeline of the booster pump 11.

[0049] Furthermore, the underwater flexible liquid ammonia storage device 9 adopts a non-metallic flexible bag as an existing structure, the bottom of the non-metallic flexible bag is connected to the anchor chain 10, and the end of the anchor chain 10 is anchored on the seabed. Since the density of liquid ammonia is less than the density of seawater, in order to make the non-metallic flexible bag storing liquid ammonia suspended at a certain stable depth in the seawater, the anchor chain 10 provides a force for the underwater flexible liquid ammonia storage device 6 to be suspended in the water, so as to fix the underwater flexible liquid ammonia storage device 9 at a set depth below the sea surface.

[0050] In this embodiment, the wind power generation device 2 supplies power to the offshore floating ammonia production vessel 4 through the power transmission system 3 .

[0051] The working principle of the deep sea floating production and storage system provided in this embodiment is as follows:

[0052] The wind power generation device 2 generates electricity using wind energy, and the generated electric energy is transmitted to the offshore floating ammonia production vessel 4 through the power transmission system 3. The offshore floating ammonia production vessel 4 produces liquid ammonia, and the generated liquid ammonia is injected into the underwater flexible liquid ammonia storage device 9 through the ammonia supply pipeline 5, the riser 6, the inlet pipe 7 and the regulating valve 8 for storage.

[0053] When liquid ammonia production and external transmission are not required, the external transmission valve 14 is closed, and the power equipment on the offshore floating ammonia production ship controls the pressure of the ammonia supply pipeline 5 to be above the saturated vapor pressure of ammonia corresponding to the transmission temperature, and injects the liquid ammonia into the underwater flexible liquid ammonia storage device along the ammonia supply pipeline 5 through the riser 6, the inlet pipeline 7 and the regulating valve 8. At the same time, because it is connected to the lower end of the riser 6, the downstream outlet pipeline 13 of the outlet check valve 12 of the booster pump 11 can maintain the internal pressure above the saturated vapor pressure of ammonia in the stop state, thereby keeping the internal ammonia in liquid phase;

[0054] When liquid ammonia needs to be produced and transported, the booster pump 11 and the transport valve 14 are turned on, and the regulating valve 8 is closed. The liquid ammonia in the flexible liquid ammonia storage device 9 passes through the booster pump 11 and the one-way valve 12, and enters the transport pipeline 15 through the riser 6. The liquid ammonia of the offshore floating ammonia production ship 4 directly enters the transport pipeline 15 through the ammonia supply pipeline 5, and then is transported to the surface ship. At this time, the pressure in the inlet pipeline 7 upstream of the regulating valve 8 is consistent with the outlet pressure of the booster pump 11, which is higher than the saturated vapor pressure of ammonia. Therefore, although the liquid ammonia in the inlet pipeline 7 stops flowing, it can still remain in liquid state, thereby avoiding the pressure fluctuations and equipment damage that may be caused by gasification.

[0055] In the above process, the liquid ammonia produced by the offshore floating ammonia production vessel can be stored by the underwater flexible liquid ammonia storage device 9. During the storage process, the seawater pressure and the stable temperature environment are fully utilized to reduce the storage cost of liquid ammonia. There is no need to set up a large-volume liquid ammonia storage tank, and a higher-power production system can be arranged in a limited space, or the manufacturing cost of the floating production system can be reduced under the same production power.

[0056] Example 2

[0057] In a typical implementation of this embodiment, a working method of a deep-sea floating production and storage ammonia system is provided, comprising the following steps:

[0058] The wind power generation device uses wind energy to generate electricity, and the generated electricity is transmitted to the offshore floating ammonia production vessel through the power transmission system. The offshore floating ammonia production vessel produces liquid ammonia, and the generated liquid ammonia is injected into the underwater flexible liquid ammonia storage device through a pipeline for storage. The water pressure provided by the seawater depth at the installation location of the underwater flexible liquid ammonia storage device is greater than the ammonia saturated vapor pressure corresponding to the seawater temperature at the installation location, so that the ammonia is always stored in a liquid state.

[0059] Furthermore, when liquid ammonia production and external transmission are not required, the external transmission valve is closed, and the power equipment on the offshore floating ammonia production vessel controls the ammonia pipeline pressure to be above the ammonia saturated vapor pressure corresponding to the transmission temperature, and injects the liquid ammonia into the underwater flexible liquid ammonia storage device through the riser and the regulating valve along the ammonia supply pipeline. At this time, the valve throttling needs to be adjusted to reduce the pressure of the liquid ammonia entering the flexible liquid ammonia storage device to the water pressure at the water depth where the flexible liquid ammonia storage device is located; at the same time, because the lower end of the riser is connected, the pipeline downstream of the pump outlet check valve can maintain the internal pressure above the ammonia saturated vapor pressure when the transmission is stopped, thereby keeping the internal ammonia in the liquid phase;

[0060] When liquid ammonia needs to be produced and exported, the pressure pump and the export valve are turned on, and the regulating valve is closed. The liquid ammonia in the flexible liquid ammonia storage device passes through the pressure pump and the one-way valve and enters the export pipeline through the riser. The liquid ammonia from the offshore floating ammonia production ship directly enters the export pipeline through the ammonia supply pipeline and is then exported to the surface ship.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A deep sea floating production and storage ammonia system, characterized in that: include: Offshore floating ammonia production vessels, located above the sea surface, are used to produce liquid ammonia; A wind power plant located above the sea surface is used to generate the energy required to produce liquid ammonia for an offshore floating ammonia production vessel; An underwater flexible liquid ammonia storage device, located below the sea surface, for storing liquid ammonia produced by an offshore floating ammonia production vessel, wherein the water pressure provided by the seawater depth at the installation location of the underwater flexible liquid ammonia storage device is greater than the ammonia saturated vapor pressure corresponding to the seawater temperature at the installation location; The liquid ammonia produced by the offshore floating ammonia production vessel is transported to an underwater flexible liquid ammonia storage device through a pipeline for storage.

2. The deep sea floating production and storage ammonia system according to claim 1, characterized in that: The underwater flexible liquid ammonia storage device is provided with a liquid ammonia inlet and a liquid ammonia outlet, the liquid ammonia inlet is connected to an inlet pipe, and the liquid ammonia outlet is connected to an outlet pipe.

3. The deep sea floating production and storage system for ammonia according to claim 2, characterized in that: The inlet pipeline is connected to the surface liquid ammonia export pipeline and the ammonia supply pipeline of the offshore floating ammonia production ship through a riser, and the lower end of the riser is also connected to the outlet pipeline.

4. The deep sea floating production and storage ammonia system according to claim 3, characterized in that: The external transmission pipeline is connected to the ammonia supply pipeline, and an external transmission valve is arranged on the external transmission pipeline.

5. The deep sea floating production and storage ammonia system according to claim 2, characterized in that: The inlet pipeline is provided with a regulating valve with a throttling and pressure reducing function, and the outlet pipeline is provided with a pressure pump and a check valve, wherein the check valve is located at the outlet of the pressure pump.

6. The deep sea floating production and storage ammonia system according to claim 5, characterized in that: The booster pump is arranged near the liquid ammonia outlet of the underwater flexible liquid ammonia storage device and its height does not exceed the highest point of the non-metallic flexible bag.

7. The deep sea floating production and storage ammonia system according to claim 1, characterized in that: The underwater flexible liquid ammonia storage device adopts a non-metallic flexible bag, the bottom of which is connected to an anchor chain, and the end of the anchor chain is anchored on the seabed.

8. The deep sea floating production and storage system of ammonia according to claim 1, characterized in that: The wind power generation device supplies power to the offshore floating ammonia production vessel through a power transmission system.

9. A method for operating a deep sea floating production and storage ammonia system according to any one of claims 1 to 8, characterized in that: The following steps are involved: The wind power generation device uses wind energy to generate electricity, and the generated electricity is transmitted to the offshore floating ammonia production vessel through the power transmission system. The offshore floating ammonia production vessel produces liquid ammonia, and the generated liquid ammonia is injected into the underwater flexible liquid ammonia storage device through a pipeline for storage. The water pressure provided by the seawater depth at the installation location of the underwater flexible liquid ammonia storage device is greater than the ammonia saturated vapor pressure corresponding to the seawater temperature at the installation location, so that the ammonia is always stored in a liquid state.

10. The operating method of the deep sea floating production and storage ammonia system according to claim 9, characterized in that: When liquid ammonia production and external transmission are not needed, the external transmission valve is closed, and the power equipment on the offshore floating ammonia production ship controls the ammonia pipeline pressure to be above the ammonia saturated vapor pressure corresponding to the transmission temperature, and injects the liquid ammonia into the underwater flexible liquid ammonia storage device through the riser and the regulating valve along the ammonia supply pipeline. At this time, the valve throttling needs to be adjusted to reduce the pressure of the liquid ammonia entering the flexible liquid ammonia storage device to the water pressure at the water depth where the flexible liquid ammonia storage device is located; at the same time, because it is connected to the lower end of the riser, the pipeline downstream of the pump outlet check valve can maintain the internal pressure above the ammonia saturated vapor pressure when the transmission is stopped, thereby keeping the internal ammonia in liquid phase; When liquid ammonia needs to be produced and exported, the pressure pump and the export valve are turned on, and the regulating valve is closed. The liquid ammonia in the flexible liquid ammonia storage device passes through the pressure pump and the one-way valve and enters the export pipeline through the riser. The liquid ammonia from the offshore floating ammonia production ship directly enters the export pipeline through the ammonia supply pipeline and is then exported to the surface ship.

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