A method for preparing supercritical fluid by using deep-sea pressure

Abstract

The present invention discloses a method for preparing supercritical fluid by using deep-sea pressure, belonging to the technical field of supercritical fluid preparation, and comprising the following steps: placing a low-pressure fluid in a sealed flexible container, using a powered or non-powered traction device to send the sealed flexible container to a depth where the seawater pressure meets the requirements, standing still until the volume of the flexible container no longer changes, then wrapping the outside of the sealed flexible container with a rigid pressure-bearing container, using a powered or non-powered traction device to send the sealed flexible container to the sea surface, taking out the fluid in the flexible container, and at this time the fluid is the supercritical fluid. Since the process of reaching supercritical (high pressure) is carried out deep in the sea, the safety and stability are higher than those of the method for preparing high-pressure fluid on land.

Description

Technical Field

[0001] The present invention relates to the technical field of supercritical fluid preparation, and particularly to a method for preparing supercritical fluid by using deep-sea pressure. Background Art

[0002] High pressure is an important way to reduce the volume of fluid and the cost of fluid transportation. For example, high-pressure gas cylinders, liquefied natural gas, liquefied petroleum gas, etc. have many applications. At the same time, when the temperature and pressure of the fluid both exceed the critical point, the fluid reaches the supercritical state. Supercritical fluids include but are not limited to supercritical water, supercritical carbon dioxide, etc. Due to their unique physical and chemical properties, supercritical fluids have been widely used in many industries such as chemical engineering, smelting, and food. To prepare supercritical fluids, the current industry mainly uses means such as mechanical extrusion and high-pressure pumps. These means mainly have two problems:

[0003] (1) The energy consumed to reach high-pressure conditions is relatively large, and the energy consumption cost is high;

[0004] (2) The safety of the high-pressure formation process is difficult to guarantee, and accidents are likely to occur. Summary of the Invention

[0005] Currently, the preparation method of supercritical fluids mainly uses a compressor to increase the pressure of low-pressure gas to the supercritical state. However, when operating a compressor or performing pressure-bearing operations in a laboratory, there are high risks, and high requirements are imposed on the operations of experimental personnel and the safety factor of equipment. When the present invention uses deep-sea pressure to prepare supercritical fluids, the fluid preparation environment is approximately a closed space, and the deep-sea pressure is in a stable state. Therefore, the safety factor and stability factor of supercritical fluids are relatively high.

[0006] In addition, when using a compressor to prepare supercritical fluids, high kinetic energy is required to compress the fluid, thereby consuming a large amount of energy. When the present invention uses deep-sea pressure to prepare supercritical fluids, methods such as tying heavy objects can be used to achieve underwater traction of the fluid, reducing energy consumption.

[0007] To achieve the above object, the present invention provides the following solution:

[0008] A method for preparing supercritical fluid by using deep-sea pressure, comprising the following steps: placing a low-pressure fluid in a closed flexible container, using a powered or unpowered traction device to send the closed flexible container to a depth where the seawater pressure meets the requirements, standing still until the volume of the flexible container no longer changes, wrapping the outside of the closed flexible container with a rigid pressure-bearing container, using a powered or unpowered traction device to send the closed flexible container to the sea surface, and taking out the fluid in the flexible container. At this time, the fluid is the supercritical fluid.

[0009] Further, the material of the flexible container includes, but is not limited to, rubber, latex, spring steel, etc., and its pressure-bearing capacity is not less than the pressure of the target supercritical fluid.

[0010] Further, the formula for calculating the depth that meets the requirements is h = P × 10 6 ÷ ρ 海水 ÷ g, where h is the seawater depth (m), P is the critical pressure (MPa), ρ 海水 is the seawater density (kg / m 3 ), and g is the acceleration due to gravity (m / s 2 ).

[0011] Further, the standing time is 0.5 - 1 h.

[0012] Further, the rigid pressure-bearing container is of an openable and closable structure.

[0013] Further, when using a non-powered traction device, it is achieved by tying heavy objects outside the rigid pressure-bearing container.

[0014] The technical key of the present invention lies in using a flexible container to wrap a low-pressure fluid and tow it to the deep sea. The flexible container is externally wrapped with a rigid container of an openable and closable structure. At the deep sea, the rigid container tightly wraps the flexible container, and the nested rigid container and flexible container are transported to the sea surface, thus obtaining a supercritical fluid. The method of towing the flexible container to the deep sea or transporting the nested rigid container and flexible container to the sea surface includes both non-powered traction methods such as gravity traction (such as tying heavy objects to the flexible container) and powered traction methods such as submersible machinery and mechanical telescopic rods.

[0015] The present invention discloses the following technical effects:

[0016] (1) Since the process of reaching supercritical (high pressure) is at the deep sea, the safety and stability are higher than the method of preparing high-pressure fluids on land;

[0017] (2) The energy consumption of high-pressure fluid preparation is significantly reduced. When using a non-powered traction method to make the flexible container reach the deep sea (such as tying heavy objects to the flexible container) and the density of the finally obtained high-pressure fluid is less than the seawater density, the high-pressure fluid preparation process theoretically has no energy consumption. Detailed Embodiments

[0018] Now, various exemplary embodiments of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0019] It should be understood that the terms described in the present invention are only for describing specific embodiments and are not intended to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0020] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0021] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific embodiments of the present invention specification, which are obvious to those skilled in the art. Other embodiments obtained from the present invention specification are obvious to those skilled in the art. The present invention specification and examples are merely exemplary.

[0022] Regarding the use of "comprising", "including", "having", "containing", etc. herein, they are all open-ended terms, meaning including but not limited to.

[0023] A container with a deformation ability under internal pressure of the container much smaller than that under external pressure of the container can be regarded as equivalent to the nested rigid container and flexible container described in the present invention.

[0024] In the present invention, the seawater density is calculated based on 1.02×10 3 kg / m 3 and the gravitational acceleration of 9.8 m / s 2 .

[0025] In the following embodiments, the process of the rigid container wrapping the flexible container can be remotely controlled by a remote controller. At present, there are already remote control devices with a range of over 5000 m on the market, and the openable rigid container of the present invention can be obtained by purchase.

[0026] The gravity-driven waste in the embodiments of the present invention can be remotely released to the seabed during the opening and closing process of the rigid container. It can also be towed out of the sea surface with the help of power traction.

[0027] In the present invention, P1 refers to the critical pressure of the supercritical fluid.

[0028] In the present invention, the flexible container is wrapped by an openable and closable rigid container. Before being put into the water, the openable and closable rigid container is in an open state. After the volume of the flexible container is compressed in the deep sea (reaching the specified depth within 0.5 - 1 h), through a super-long-distance remote control device, the openable and closable rigid container is wrapped around the outer surface of the compressed flexible container, and then it is pulled out of the sea surface.

[0029] In the present invention, the wastes for gravitational settlement include non-usable nuclear wastes (meeting the requirements of the nuclear waste ocean burial law), wastes for land reclamation (such as cement), etc. After reaching the specified depth, heavy objects can be dropped through remote control, and then the container including the supercritical fluid is pulled out of the sea surface by a tractor, which not only realizes the treatment of the wastes but also successfully prepares the supercritical fluid.

[0030] Example 1 Preparation of supercritical CO2 fluid by deep-sea pressure

[0031] The critical pressure of supercritical CO2 fluid is 7.38 MPa. Fill the CO2 fluid at normal pressure into a high-pressure-resistant flexible container made of rubber (with a density of 1.6 g / cm 3 ) with a volume of 1 m 3 (the pressure-bearing capacity is higher than 7.38 MPa), and load an openable and closable rigid container made of aluminum alloy with a volume of 0.013 m 3 on top of this flexible container. Under the traction of 1.5 t of wastes (wastes that do not pollute seawater, such as construction waste cement), it is put into the deep sea, and the input depth is about 738 m (the calculation formula is h = P×10 6 ÷ρ 海水 ÷g = 7.38×10 6 ÷(1.02×10 3 )÷9.8 = 738.3 m). After 0.5 h of input, the volume of the flexible container is compressed under the deep-sea pressure, and the fluid pressure inside it reaches the required high pressure P1 = 7.38 MPa. At this pressure, the volume of the flexible container is compressed to 0.0012 m 3 . At this time, through a super-long-distance remote control device, the openable aluminum alloy rigid container is wrapped around the compressed flexible container, and it is pulled out of the sea surface with the help of a tractor. The fluid inside the flexible container is taken out by means of a valve, etc. The result shows that finally 0.0012 m 3 of supercritical CO2 is obtained.

[0032] Example 2 Preparation of supercritical water by deep-sea pressure

[0033] The critical pressure of supercritical water is 22.1 MPa. Fill 0.8 m 3 of pure water at normal pressure into 1 m 3 of latex (with a density of 1.6 g / cm 3) in a high-pressure flexible container (with a pressure bearing capacity higher than 22.1MPa) and the volume after sealing is 0.005m 3 The retractable aluminum alloy rigid container is loaded on the flexible container and thrown into the deep sea under the traction of 3t of waste (waste that will not pollute the seawater, such as construction material waste cement), with a depth of about 2211m (the calculation formula is h = P × 10 6 ÷ρ 海水 ÷g=7.38×10 6 ÷(1.02×10 3 )÷9.8=2210.898m). After 0.5h of being put into the water, the volume of the flexible container is compressed under the deep sea pressure, and the fluid pressure inside it reaches the required high pressure P1=22.1MPa. Under this pressure, the volume of the flexible container is compressed to 0.004m 3 At this time, the open and close aluminum alloy rigid container is wrapped around the compressed flexible container through ultra-long-distance remote control equipment, and pulled out of the sea with the help of a tractor, and the fluid in the flexible container is taken out by means of valves and other methods. The results show that 0.004m 3 of supercritical water.

[0034] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing supercritical fluid by using deep-sea pressure, characterized in that, The steps include: placing a low-pressure fluid in a sealed flexible container, using a powered or unpowered traction device to send the sealed flexible container to a depth where the seawater pressure meets the requirements, standing still until the volume of the sealed flexible container no longer changes, wrapping a rigid pressure-bearing container around the outside of the sealed flexible container, using a powered or unpowered traction device to send the sealed flexible container wrapped with the rigid pressure-bearing container to the sea surface, and taking out the fluid in the sealed flexible container. At this time, the fluid is the supercritical fluid; The pressure-bearing capacity of the sealed flexible container is not less than the pressure of the target supercritical fluid; The calculation formula for the depth meeting the requirements is h = P × 10 6 ÷ ρ 海水 ÷ g, where h is the seawater depth (m), P is the critical pressure (MPa), ρ 海水 is the seawater density (kg / m 3 ), and g is the acceleration due to gravity (m / s 2 ); The standing still time is 0.5 - 1 h; The rigid pressure-bearing container is of an openable and closable structure.

2. The method for preparing supercritical fluid by using deep-sea pressure according to claim 1, characterized in that The material of the sealed flexible container includes but is not limited to rubber, latex, and spring steel.

3. The method for preparing a supercritical fluid by using deep-sea pressure according to claim 1, characterized in that, When using an unpowered traction device to send the sealed flexible container to the deep sea, it is achieved by tying a heavy object to the sealed flexible container.