Method and device for quantitatively adding supercritical / subcritical fluid reaction materials

Abstract

The invention discloses a method and device for quantitatively adding supercritical / subcritical fluid reaction materials, and the method comprises the steps: 1) monitoring the reaction state of fluid in a reaction kettle, including temperature T1 and pressure p1; (2) adding a to-be-added material into the sample adding tank, and inquiring a phase diagram of the phase state and density rho of the to-be-added material under the conditions of temperature T and pressure p; (3) determining the required adding amount of the material, heating the material in the sample adding tank to a temperature T2, enabling the material to reach a uniform gas state or a supercritical state, recording the starting pressure p2 of the material in the sample adding tank at the moment, confirming the corresponding relation between the pressure and the density at the temperature T2 through phase diagram data, and calculating the pressure drop delta p corresponding to the added quantitative material, and then the materials are introduced into the reaction kettle from the sample adding tank according to the data, so that quantitative sample adding is completed. The device can realize accurate addition of materials in the reaction process, can be applied to the reaction process in which alcohol, carbon dioxide, hydrogen, oxygen and the like are used as reaction media or reactants, and is simple and convenient to operate.

Description

Technical Field

[0001] This invention relates to the field of metrology technology for chemical laboratory equipment, specifically to a method and apparatus for quantitatively adding materials to supercritical / subcritical fluid reactants. Background Technology

[0002] Supercritical / subcritical fluids have densities close to liquids but lower viscosity, making the transport of substances in them far superior to that in liquids. The diffusion coefficients of supercritical / subcritical fluids fall between those of gases and liquids, typically 10 to 100 times that of liquids, enabling more efficient transport and diffusion in chemical reactions. The properties of supercritical / subcritical fluids can be altered by adjusting pressure and temperature to suit different chemical reaction requirements. This makes them excellent for rapid chemical reactions, diffusion-controlled reactions, or reactions involving gaseous reactants. Due to their high solubility, excellent diffusivity, environmental benefits, ease of control and regulation, and applicability to a wide range of chemical reactions, supercritical / subcritical fluid reactions have broad application prospects in the chemical industry.

[0003] Currently, supercritical / subcritical reactions are typically carried out in reactors. One patent, CN208802883U, discloses a supercritical fluid reaction apparatus, including a reactor, heating device, pressure control device, and gas supply system, used for chemical reactions under supercritical conditions. Another patent, CN113198391A, discloses a device system for precise pressure control in hydrothermal liquefaction reactions, including a reactor, a one-way valve, a pressure detection system, a pressurized filter, a gas cylinder, and a pressurized water supply device. By pressurizing water into the lower chamber of the pressurized filter, the water level rises, causing the semi-permeable membrane to rise, thus pressurizing the stored gas into the reactor. This increases the pressure inside the reactor, and repeated operation can bring the reactor pressure to a preset value. However, these patents only regulate the pressure of the reactor using the pressurization device; they cannot measure the amount of substances added. In the invention patent "A Supercritical Fluid Injection Device" (CN102310516A), a constant pressure and constant flow injection system for supercritical fluids is disclosed, employing a two-stage air compressor, a refrigeration unit, and a heater. However, because the device uses the air compressor as the power source for material injection, it cannot precisely quantify the injection volume. A quantitative feeding method (ZL202311167287.2) discloses a method that uses a fluidized bed pump for quantitative feeding. By adjusting the opening of each gas valve, the solid concentration and solid conveying capacity are balanced. However, this invention uses a fluidized bed pump to add fluidizable solid materials, making it impossible to quantitatively add gaseous and liquid materials. Currently, metering pumps are commonly used for supercritical fluid reaction sampling, with flow rates ranging from 0.1 to 20000 L / h and an accuracy of ±1%.

[0004] In summary, supercritical / subcritical reactions typically involve high temperatures and pressures, and conventional metering pumps used for precise sample addition are complex and inaccurate under these conditions. Therefore, precise quantitative sample addition during supercritical / subcritical reactions remains a challenge. Summary of the Invention

[0005] In view of the above-mentioned technical problems existing in the prior art, the purpose of the present invention is to provide a method and apparatus for quantitatively adding materials for supercritical / subcritical fluid reactions.

[0006] The technical solution adopted in this invention is as follows: A method for quantitatively adding materials for supercritical / subcritical fluid reactions includes the following steps: 1) Monitor the reaction state of the fluid inside the reactor, including the reaction temperature T1 and pressure p1; 2) Add the material to be added into the sample addition vessel and query the phase diagram data of the material to be added. The phase diagram data includes the phase state and density ρ data under certain temperature T and pressure p conditions. The sample addition vessel is connected to the reaction vessel through a sample addition pipe with a valve. 3) Determine the required amount of material to be added, heat the material in the sample tank to temperature T2, so that the material reaches a homogeneous gaseous or supercritical state, record the initial pressure of the material in the sample tank at this time as p2, confirm the relationship between pressure and density at temperature T2 through the phase diagram data in step 2), and calculate the pressure drop Δp of the sample tank corresponding to the addition of a certain amount of material. 4) While maintaining the temperature T2 of the material in the sample loading tank constant, open the valve on the sample loading pipeline to pass the material from the sample loading tank into the reactor, thereby reducing the pressure Δp in the sample loading tank and completing the quantitative sample loading.

[0007] Furthermore, the pressure p2 > p1 + Δp.

[0008] Furthermore, the process for calculating the pressure drop Δp of the sampling tank corresponding to the added quantitative material is as follows: S1: After the temperature of the material in the sample tank is heated to temperature T2, the material reaches the homogeneous gaseous or supercritical state. At this time, the initial pressure of the material is p2, and the initial density of the material is confirmed to be ρ2 by querying the phase diagram data. S2: The volume of the cavity in the sampling tank is denoted as V. The product of the cavity volume V and the decrease in material density Δρ is the amount of material to be added. Based on the required amount of material to be added, the density difference of the material in the sampling tank between the starting point and the ending point of the sampling can be calculated. Then, the final density ρ3 of the material in the sampling tank at the end of the sampling can be calculated. S3: Check the phase diagram again, record the material endpoint pressure p3 corresponding to the material endpoint density ρ3, and the pressure drop Δp of the sample tank = p2 - p3.

[0009] Furthermore, the material is a C1-C10 alkyl alcohol, oxygen, carbon dioxide, or hydrogen.

[0010] A quantitative material addition device for supercritical / subcritical fluid reactions includes a sample addition tank, a temperature control chamber, a pressure sensor, a material tank, and a reaction vessel. The sample addition tank is located in the temperature control chamber, and the pressure sensor is installed on the sample addition tank to monitor the fluid pressure inside the tank. The top of the sample addition tank is connected to the first opening of a three-way valve via a pipeline. The second opening of the three-way valve is connected to the material tank via a pipeline, and the third opening of the three-way valve is connected to the reaction vessel via a high-pressure resistant pipeline for adding materials into the reaction vessel. Control valves are installed on the corresponding pipelines. The high-pressure needle valve and the check valve are installed on the high-pressure resistant pipeline between the third opening of the three-way valve and the reactor, so that the material in the sample tank can be quantitatively and controllably introduced into the reactor.

[0011] Furthermore, a pressure gauge is installed on the reactor, a heating jacket is installed on the outer side of the reactor sidewall, a base is installed at the bottom of the reactor and the heating jacket, and a temperature controller is installed inside the base. The detection end of the temperature controller is located on the inner wall of the reactor. The temperature controller can detect the temperature inside the reactor in real time and is used to adjust the heating temperature of the heating jacket.

[0012] Compared with the prior art, the beneficial effects achieved by the present invention are: This application addresses the challenge of precise quantitative addition in supercritical / subcritical reaction processes by providing a method and apparatus for quantitative material addition in supercritical / subcritical fluid reactions. This method achieves precise material addition during the reaction process by controlling the amount of material added to the addition vessel and the temperature of the addition vessel. It can be applied to reaction processes using alcohols, carbon dioxide, hydrogen, and oxygen as reaction media or reactants. The apparatus is simple and easy to operate. Attached Figure Description

[0013] Figure 1 This is a flowchart illustrating a method for quantitatively adding supercritical / subcritical fluid reactants according to an embodiment of this application; Figure 2 This is a schematic diagram of the calculation process for a method of quantitatively adding supercritical / subcritical fluid reactants according to an embodiment of this application; Figure 3 This is a schematic diagram of a device for quantitatively adding supercritical / subcritical fluid reactants according to an embodiment of this application; In the diagram: 1. Temperature controller; 2. Reactor; 3. Pressure gauge; 4. High-pressure needle valve; 5. Check valve; 6. Three-way valve; 7. Pressure sensor; 8. Sample loading vessel; 9. Temperature control box; 10. Material container.

[0014] Figure 4 This is the p-ρ phase diagram of methanol at 250℃; Figure 5It is the self-generated pressure of pure water at different temperatures; Figure 6 This is the p-ρ phase diagram of methanol at 250℃ under pressure p in the range of 9.10 MPa-10.10 MPa. Figure 7 This is the p-ρ phase diagram of methanol at 250℃ under pressure p in the range of 10.000MPa-10.100MPa. Detailed Implementation

[0015] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0016] The technical concept of this application is to address the challenge of precise quantitative sample addition in supercritical / subcritical reaction processes by proposing a method for quantitative material addition. This method utilizes the physicochemical properties of materials, specifically the correlation between density and content and pressure under certain temperature and volume conditions. The material is introduced into the supercritical / subcritical reaction system using a pressure difference. This application employs a quantitative material addition device. When a specific amount of material needs to be added during the reaction process, an excess of the material is added to the addition tank. The temperature of the temperature control chamber is adjusted to ensure the raw material in the addition tank reaches a homogeneous gaseous or supercritical state. The pressure in the addition tank is recorded, and the pressure drop in the addition tank when the precise amount of material is added is calculated. The high-pressure needle valve is then opened to allow the material to flow from the addition tank into the reaction vessel, reducing the pressure in the addition tank accordingly. Finally, the high-pressure needle valve is closed, completing the precise quantitative sample addition process. The following detailed description, in conjunction with the accompanying drawings, illustrates the solutions provided by various embodiments of this application.

[0017] This application provides a quantitative material addition method for supercritical / subcritical fluid reactions, such as... Figure 1 The diagram shows a flowchart of a quantitative material addition method for supercritical / subcritical fluid reactions, the method comprising at least the following steps S110 to S140: S110: When a certain material needs to be added quantitatively in a supercritical / subcritical fluid reaction process, the material properties and the state of the reactor are used as the basis for adding the material properties and the reactor state. The material properties include basic phase diagram data, which includes phase state and density ρ data under certain temperature T and pressure p conditions. The reactor state includes the reaction process temperature T1 and pressure p1 in the reactor. S120: Determine the amount of material to be added to the sample loading tank, and adjust the temperature control box of the sample loading device to temperature T2 so that the material in the sample loading tank reaches a uniform gaseous or supercritical state. S130: Calculate the pressure drop Δp in the sample loading tank corresponding to the addition of a fixed amount of material; S140: The material is introduced into the reactor through the sample loading tank, causing the pressure Δp in the sample loading tank to be reduced accordingly, thus completing the quantitative addition of material.

[0018] A further flowchart illustrating the quantitative material addition method is shown below. Figure 2 As shown in this application, based on the properties of the material and the state of the reactor, the pressure is higher than p1 + Δp when the material is added to the sample tank and reaches temperature T2. The amount of material added to the sample tank is then determined. After the material is added to the sample tank, under the temperature control chamber of the sample addition device at temperature T2, the material reaches the homogeneous gaseous or supercritical state, with material pressure p2 and density ρ2. Based on the basic data of the material phase diagram, the material density ρ3 and pressure p3 in the sample tank after adding a quantitative amount of material are obtained. The pressure drop Δp in the sample tank is the difference between p2 and p3.

[0019] This application pertains to a metering device for supercritical / subcritical fluid reactions; see [link to relevant documentation]. Figure 3 It includes a sample loading tank 8, a temperature control chamber 9, a pressure sensor 7, and a material tank 10, for temperature control and pressure detection of the material in the sample loading tank. The sample loading tank 8 is located in the temperature control chamber 9, and the pressure sensor 7 is installed on the sample loading tank 8 to monitor the fluid pressure inside the sample loading tank 8. The sample loading tank 8 is connected to the material tank 10.

[0020] The top of the sample loading vessel 8 is connected to the first opening of the three-way valve 6 via a pipeline. The second opening of the three-way valve 6 is connected to the material tank 10 via a pipeline. The third opening of the three-way valve 6 is connected to the reactor 2 via a high-pressure resistant pipeline for adding materials into the reactor 2. The high-pressure resistant pipeline is equipped with a high-pressure needle valve 4 and a one-way valve 5 to ensure that the material in the sample loading vessel is quantitatively and controllably introduced into the reactor. A pressure gauge 3 is installed on the reactor 2.

[0021] Example 1: In the experiment of quantitatively adding methanol as a reactant in a supercritical / subcritical water reaction, the reaction system was a pure water system, the temperature T1 was 250℃, and the pressure was the saturated vapor pressure of water at that temperature, which was approximately 3.98 MPa. 11.00 mol (352.44 g) of methanol was added to a 1 L sample loading vessel at room temperature.

[0022] The p-ρ phase diagram of methanol at 250℃ is as follows Figure 4 As shown, this illustrates the correlation between pressure and density. Figure 6 This represents the p-ρ phase diagram of methanol at 250℃ under pressure p within the range of 9.10 MPa-10.10 MPa. Figure 7 This represents the p-ρ phase diagram of methanol at 250℃ under pressure p within the range of 10.000MPa-10.100MPa.

[0023] The autogenous pressure of pure water at different temperatures, such as Figure 5 As shown.

[0024] The temperature control box 9 of the sampling device is adjusted to temperature T2. Under the condition that the temperature T2 of the sampling tank 8 is 250℃ and the pressure is 10.10MPa, the material in the sampling tank 8 reaches a uniform supercritical state. According to the basic data of methanol phase diagram, the methanol density in the sampling tank 8 at this time is 11.00 mol / L.

[0025] Optional calculations show that the pressure drop Δp corresponding to the addition of a quantitative amount of material in the sample loading vessel 8 is 0.01 MPa to 3.00 MPa (maximum pressure difference). Open the three-way valve 6 to connect the sample loading vessel 8 to the left-side pipeline. Slowly open the high-pressure needle valve 4 to control the pressure reading in the pressure sensor 7 (a commonly used laboratory pressure sensor with an accuracy of 0.01 MPa) to decrease by Δp. Since the pressure in the sample loading vessel 8 is higher than the pressure in the reaction vessel 2, methanol in the sample loading vessel 8 enters the reaction vessel 2, allowing the material to be introduced from the sample loading vessel 8 into the reaction vessel 2, thus reducing the pressure in the sample loading vessel 8 by the corresponding Δp. This completes the quantitative addition of 0.029 mol to 5.49 mol (the addition accuracy is related to the pressure gauge accuracy of ±0.01 MPa; the addition accuracy is ±0.029 mol = ±0.93 g).

[0026] For example, if 96.12 g of methanol (3.00 mol methanol) needs to be added, then Δp needs to be controlled at 0.54 MPa and p3 needs to be set to 9.56 MPa.

[0027] The contents described in this specification are merely an enumeration of the implementation forms of the inventive concept, and the scope of protection of this invention should not be regarded as limited to the specific forms described in the embodiments.

Claims

1. A method for quantitatively adding reactants to supercritical / subcritical fluids, characterized in that... Includes the following steps: 1) Monitor the reaction state of the fluid inside the reactor, including the reaction temperature T1 and pressure p1; 2) Add the material to be added into the sample addition vessel and query the phase diagram data of the material to be added. The phase diagram data includes the phase state and density ρ data under certain temperature T and pressure p conditions. The sample addition vessel is connected to the reaction vessel through a sample addition pipe with a valve. 3) Determine the required amount of material to be added, heat the material in the sample tank to temperature T2, so that the material reaches a homogeneous gaseous or supercritical state, record the initial pressure of the material in the sample tank at this time as p2, confirm the relationship between pressure and density at temperature T2 through the phase diagram data in step 2), and calculate the pressure drop Δp of the sample tank corresponding to the addition of a certain amount of material. 4) While maintaining the temperature T2 of the material in the sample loading tank constant, open the valve on the sample loading pipeline to pass the material from the sample loading tank into the reactor, thereby reducing the pressure Δp in the sample loading tank and completing the quantitative sample loading.

2. The method for quantitative addition of reactants in supercritical / subcritical fluids as described in claim 1, characterized in that... The pressure p2 > p1 + Δp.

3. The method for quantitative addition of reactants in supercritical / subcritical fluids as described in claim 1, characterized in that... The process for calculating the pressure drop Δp in the sampling tank corresponding to the addition of a quantitative amount of material is as follows: S1: After the temperature of the material in the sample tank is heated to temperature T2, the material reaches the homogeneous gaseous or supercritical state. At this time, the initial pressure of the material is p2, and the initial density of the material is confirmed to be ρ2 by querying the phase diagram data. S2: The volume of the cavity in the sampling tank is denoted as V. The product of the cavity volume V and the decrease in material density Δρ is the amount of material to be added. Based on the required amount of material to be added, the density difference of the material in the sampling tank between the starting point and the ending point of the sampling can be calculated. Then, the final density ρ3 of the material in the sampling tank at the end of the sampling can be calculated. S3: Check the phase diagram again, record the material endpoint pressure p3 corresponding to the material endpoint density ρ3, and the pressure drop Δp of the sample tank = p2 - p3.

4. The method for quantitative addition of reactants in supercritical / subcritical fluids as described in claim 1, characterized in that... The material is a C1-C10 alkyl alcohol, oxygen, carbon dioxide, or hydrogen.

5. A metering device for supercritical / subcritical fluid reactions based on the method of claim 1, characterized in that... The system includes a sample loading tank (8), a temperature control box (9), a pressure sensor (7), a material tank (10), and a reaction vessel (2). The sample loading tank (8) is located in the temperature control box (9), and the pressure sensor (7) is installed on the sample loading tank (8) to monitor the fluid pressure inside the sample loading tank (8). The top of the sample loading tank (8) is connected to the first opening of a three-way valve (6) through a pipeline. The second opening of the three-way valve (6) is connected to the material tank (10) through a pipeline. The third opening of the three-way valve (6) is connected to the reaction vessel (2) through a high-pressure resistant pipeline for adding materials into the reaction vessel (2). Control valves are installed on the corresponding pipelines. Among them, a high-pressure needle valve (4) and a one-way valve (5) are installed on the high-pressure resistant pipeline between the third opening of the three-way valve (6) and the reactor (2) so that the material in the sample tank can be quantitatively and controllably introduced into the reactor.

6. The apparatus as described in claim 5, characterized in that... A pressure gauge (3) is installed on the reactor (2). A heating jacket is installed on the outer side wall of the reactor (2). A base (1) is installed at the bottom of the reactor (2) and the heating jacket. A temperature controller is installed inside the base (1). The detection end of the temperature controller is installed on the inner wall of the reactor (2). The temperature inside the reactor (2) can be detected in real time through the temperature controller, which is used to adjust the heating temperature of the heating jacket.

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