A method of preparing a supercritical carbon dioxide purged hydrate

Abstract

The present application relates to the technical field of hydrate preparation, and particularly relates to a supercritical carbon dioxide purging hydrate preparation method.The technical scheme comprises the following steps: preparation: grinding target hydrate powder into fine particles; preparing supercritical carbon dioxide, ensuring that the purity is higher than 99%; cleaning a stainless steel high-pressure container and ensuring that the sealing performance is good; preparing a detergent, and using the detergent to remove impurities on the surface of the target hydrate; loading: putting the ground target hydrate particles into the stainless steel high-pressure container, and adding the detergent to clean the target hydrate.The present application avoids the damage of high temperature to the structure of the target substance in the traditional method, does not produce harmful substances in the preparation process, can be recycled, has high penetration ability and dissolution ability, can fully purify and clean the impurities in the target hydrate, improves the purity, preparation efficiency and product quality, and is easy to popularize.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrate preparation, and particularly relates to a preparation method of supercritical carbon dioxide purging hydrate. BACKGROUND

[0002] The situation of carbon dioxide emission is extremely serious, in recent years, the technology of recovering and storing carbon dioxide by using gas hydrate method has attracted wide attention of international scholars. The carbon dioxide gas hydrate is a kind of clathrate crystalline compound formed by water and carbon dioxide gas under certain temperature and pressure conditions. The carbon dioxide gas fixation and storage by using the hydrate method has good development prospects, mainly in the following aspects:

[0003] (1) Large gas storage density. Studies have shown that 1m3 of hydrate can carry 150-160m3 of gas under standard conditions;

[0004] (2) Easy to achieve preparation conditions. Carbon dioxide hydrate can be prepared under the conditions of 1-4Mpa and 0-10℃;

[0005] (3) Safe storage. The thermophysical properties of hydrate are relatively stable, which is much better than the storage of liquid carbon dioxide;

[0006] (4) Wide application field. The carbon dioxide gas hydrate can be used for food preservation and storage, seawater desalination, gas separation, solution concentration, wastewater treatment and other industrial and agricultural production, which is simple and feasible and achieves the purpose of turning waste into treasure.

[0007] The generation of gas hydrate is a slow crystallization process, accompanied by gas-liquid-solid three-phase heat and mass transfer process, and there is a characteristic of high temperature destroying the structure of target substances. Therefore, the present application provides a preparation method of supercritical carbon dioxide purging hydrate. SUMMARY

[0008] The purpose of the present application is to solve the problem of high temperature destroying the structure of target substances in the background art, and provide a preparation method of supercritical carbon dioxide purging hydrate.

[0009] The technical scheme of the present application is a preparation method of supercritical carbon dioxide purging hydrate, comprising the following steps:

[0010] Step S1, preparation work:

[0011] Step S101, grinding the target hydrate powder into fine particles;

[0012] Step S102, preparing supercritical carbon dioxide, and ensuring that the purity is higher than 99%;

[0013] Step S103, clean the stainless steel high-pressure container and ensure its sealing performance;

[0014] Step S104, prepare the detergent, and use the detergent to remove impurities on the surface of the target hydrate;

[0015] Step S2, loading work: put the ground target hydrate particles into the stainless steel high-pressure container, and add the detergent to clean the target hydrate;

[0016] Step S3, close the container, tightly close the stainless steel high-pressure container, and ensure that there is no leakage at the sealing position;

[0017] Step S4, supercritical carbon dioxide flushing, specifically including the following steps:

[0018] Step S401, control the temperature and pressure of the stainless steel high-pressure container containing the target hydrate and the detergent, the temperature is between 40-100 degrees Celsius, and the pressure is 1-5 MPa, so that the supercritical carbon dioxide enters the stainless steel high-pressure container, and the carbon dioxide wraps the hydrate particles in the supercritical state;

[0019] Step S402, control the flow of supercritical carbon dioxide by adjusting the flow control valve, adjust the flow and time of supercritical carbon dioxide, the flow size is 1-10 ml / min, and the time adjustment range is 30-100 min, in order to fully flush and clean the target hydrate;

[0020] Step S5, extract the supercritical carbon dioxide and the detergent from the stainless steel high-pressure container, separate the hydrate particles and the detergent by high-efficiency centrifuge, and repeat the separation for 3-5 times;

[0021] Step S6, drying: dry the target hydrate separated from the detergent in an oven for 1-20 min to obtain the supercritical carbon dioxide flushed hydrate.

[0022] Optionally, in step S101, the target hydrate powder is ground into fine particles, specifically, the clean and dry target hydrate powder is put into the grinding cavity of the ball mill, the powder treated by ball milling for 3-5 hours is passed through a 200-mesh screen, and then put into the air bellow for drying to obtain the target hydrate powder.

[0023] Optionally, the detergent is any one of propyl alcohol, butyl alcohol, diethyl ether, and isopropyl ether.

[0024] Optionally, in step S102, the supercritical carbon dioxide is prepared by filling liquid carbon dioxide into the high-pressure container of the supercritical carbon dioxide equipment, using a temperature controller to heat the liquid carbon dioxide in the high-pressure container to reach the supercritical state, and using a combination of a pressure sensor and a pressure regulator to control the pressure in the container to reach the supercritical point.

[0025] Optionally, in the step S102, the method further comprises:

[0026] Storage and purification: The supercritical carbon dioxide is transferred to a storage container, and activated carbon adsorption and molecular sieve treatment are used to remove residual impurities and impure substances.

[0027] Analysis of purity: The supercritical carbon dioxide is analyzed using a gas chromatograph.

[0028] Optionally, the specific steps for cleaning the stainless steel high-pressure container are as follows: using a mixture of warm water and a neutral cleaner, wiping the surface with a soft cloth or sponge, then using diluted bleach and gently wiping the stainless steel surface with a brush.

[0029] Optionally, in the step S401, the stainless steel container is placed in a constant temperature tank to control the temperature, and an electronic pressure control system is used to control the pressure.

[0030] Optionally, the electronic pressure control system comprises:

[0031] Pressure sensor: used to directly measure the pressure change in the high-pressure container and convert it into an electrical signal;

[0032] PLC controller: used to control the pressure in the high-pressure container;

[0033] Proportional valve: used to adjust the flow of fluid or gas according to the control signal, thereby controlling the pressure in the high-pressure container;

[0034] Solenoid valve: used to actually adjust the pressure in the high-pressure container according to the control signal.

[0035] Control panel: including a display screen and an operation interface, used to monitor and control the running state of the system, and to set and adjust system parameters.

[0036] Optionally, in the step S6, the temperature of the oven is set to 40-80℃.

[0037] Compared with the prior art, the present application has the following beneficial technical effects:

[0038] The use of supercritical carbon dioxide can perform hydrate purging at a lower temperature, avoiding the destruction of the structure of the target substance caused by high temperature in the traditional method.

[0039] Supercritical carbon dioxide is an environmentally friendly solvent that does not produce harmful substances during preparation and can be recycled.

[0040] Supercritical carbon dioxide has high permeability and solubility in a supercritical state, which can fully purify and clean impurities in the target hydrate, improving its purity.

[0041] The physical properties of supercritical carbon dioxide can achieve a rapid and controllable hydrate purging process by adjusting the temperature and pressure, thereby improving the preparation efficiency and product quality.

[0042] The preparation method is suitable for various types of hydrates and can be applied in laboratory and industrial production.

[0043] The present application avoids the damage to the structure of the target substance caused by high temperature in the conventional method, does not produce harmful substances during the preparation process, can be recycled, has high penetration and dissolution capacity, can fully purify and clean the impurities in the target hydrate, and improves the purity, preparation efficiency and product quality, and is easy to popularize. DETAILED DESCRIPTION

[0044] The embodiments of the present application will be described in detail below with specific examples. Those skilled in the art can easily understand other advantages and effects of the present application from the disclosure. The present application can also be implemented or applied in different specific embodiments, and various modifications or changes can be made to the details in the specification without departing from the spirit of the present application. It should be noted that the following examples and features in the examples can be combined with each other without conflict.

[0045] Example 1

[0046] The preparation method of hydrate purging by supercritical carbon dioxide comprises the following steps:

[0047] Step S1, preparation:

[0048] Step S101, grinding the target hydrate powder into fine particles. Specifically, clean and dry target hydrate powder is placed in the grinding cavity of a ball mill, the powder treated by 3 hours of ball milling is sieved through a 200 mesh screen, and then placed in a bellows for drying to obtain the target hydrate powder;

[0049] Step S102, preparing supercritical carbon dioxide with a purity higher than 99%. The specific method for preparing supercritical carbon dioxide is to fill liquid carbon dioxide into a high-pressure container of a supercritical carbon dioxide device, use a temperature controller to heat the liquid carbon dioxide in the high-pressure container to reach a supercritical state, and at the same time, use a combination of a pressure sensor and a pressure regulator to control the pressure in the container to reach the supercritical point;

[0050] Storage and purification: The supercritical carbon dioxide is transferred to a storage container, and activated carbon adsorption and molecular sieve treatment are used to remove residual impurities and impurities.

[0051] The purity of analysis is analyzed by using a gas chromatograph for supercritical carbon dioxide;

[0052] Step S103, clean the stainless steel high-pressure container and ensure its sealing performance, the specific steps of cleaning the stainless steel high-pressure container are: using a mixture of warm water and soap, wiping the surface with a soft cloth or sponge. This method is suitable for general dirt and grease, then using dilute bleach, and gently wiping the stainless steel surface with a brush;

[0053] Step S104, prepare the detergent, use the detergent to remove impurities on the surface of the target hydrate, the detergent is propanol;

[0054] Step S2, loading work: put the ground target hydrate particles into the stainless steel high-pressure container, and add detergent to clean the target hydrate;

[0055] Step S3, close the container, tightly close the stainless steel high-pressure container and ensure that there is no leakage at the sealing place;

[0056] Step S4, supercritical carbon dioxide flushing, specifically including the following steps:

[0057] Step S401, control the temperature and pressure of the stainless steel high-pressure container containing the target hydrate and the detergent, the temperature is between 40 degrees Celsius, and the pressure is 1MPa, so that the supercritical carbon dioxide enters the stainless steel high-pressure container. In the supercritical state, the carbon dioxide will wrap the hydrate particles, so as to dissolve and clean the impurities in them; control the temperature by placing the stainless steel container in a constant temperature tank, and control the pressure by using an electronic pressure control system.

[0058] Among them, the electronic pressure control system includes:

[0059] Pressure sensor: used for directly measuring the pressure change in the high-pressure container and converting it into an electrical signal;

[0060] PLC controller: used for controlling the pressure in the high-pressure container;

[0061] Proportional valve: according to the control signal to adjust the flow of fluid or gas, and then control the pressure in the high-pressure container;

[0062] Solenoid valve: used to actually adjust the pressure in the high-pressure container according to the control signal.

[0063] Control panel: including display screen and operation interface, used for monitoring and controlling the running state of the system, and setting and adjusting the system parameters;

[0064] Step S402, control the flow of supercritical carbon dioxide by adjusting the flow control valve, adjust the flow and time of supercritical carbon dioxide, the flow size is 1 ml / min, the time adjustment range is 30 min, to fully flush and clean the target hydrate;

[0065] Step S5, the supercritical carbon dioxide and the detergent are extracted from the stainless steel high-pressure container, the hydrate particles and the detergent are separated by a high-efficiency centrifuge, and the separation is repeated for 3 times;

[0066] Step S6, drying: the target hydrate separated from the detergent is dried in an oven for 1 min, the temperature of the oven is set to 40℃, and the supercritical carbon dioxide flushed hydrate is obtained.

[0067] Example 2

[0068] The preparation method of the supercritical carbon dioxide flushed hydrate comprises the following steps:

[0069] Step S1, preparation:

[0070] Step S101, grind the target hydrate powder into fine particles, specifically, put the clean and dry target hydrate powder into the grinding cavity of a ball mill, pass the powder treated by 4 hours of ball milling through a 200 mesh screen, and then put it into a bellows for drying to obtain the target hydrate powder;

[0071] Step S102, prepare supercritical carbon dioxide, ensure that its purity is higher than 99%, the specific method for preparing supercritical carbon dioxide is to fill liquid carbon dioxide into a high-pressure container of a supercritical carbon dioxide device, use a temperature controller to heat the liquid carbon dioxide in the high-pressure container to reach a supercritical state; at the same time, use a combination of a pressure sensor and a pressure regulator to control the pressure in the container to reach the supercritical point;

[0072] Storage and purification, transfer the supercritical carbon dioxide to a storage container, and use activated carbon adsorption and molecular sieve treatment to remove residual impurities and impurities;

[0073] Purity analysis, analyze the supercritical carbon dioxide using a gas chromatograph;

[0074] Step S103, clean the stainless steel high-pressure container and ensure that it has good sealing performance, the specific steps for cleaning the stainless steel high-pressure container are as follows: use a mixture of warm water and a neutral cleaner to wipe the surface with a soft cloth or sponge. This method is suitable for general dirt and grease, then use diluted bleach and gently wipe the stainless steel surface with a brush;

[0075] Step S104, prepare the detergent, use the detergent to remove impurities on the surface of the target hydrate, and the detergent is butanol;

[0076] Step S2, loading work: put the ground target hydrate particles into a stainless steel high-pressure container, and add a detergent to clean the target hydrate;

[0077] Step S3, sealing the container, tightly seal the stainless steel high-pressure container and ensure that there is no leakage at the sealing position;

[0078] Step S4, supercritical carbon dioxide flushing, specifically including the following steps:

[0079] Step S401, control the temperature and pressure of the stainless steel high-pressure container containing the target hydrate and the detergent, the temperature is between 70 degrees Celsius, and the pressure is 3MPa, so that the supercritical carbon dioxide enters the stainless steel high-pressure container. In the supercritical state, the carbon dioxide will wrap the hydrate particles, thereby dissolving and cleaning the impurities therein; when controlling the temperature, the stainless steel container is placed in a constant temperature tank, and the electronic pressure control system is used to control the pressure.

[0080] Among them, the electronic pressure control system includes:

[0081] Pressure sensor: used for directly measuring the pressure change in the high-pressure container and converting it into an electrical signal;

[0082] PLC controller: used for controlling the pressure in the high-pressure container;

[0083] Proportional valve: adjusts the flow of fluid or gas according to the control signal, thereby controlling the pressure in the high-pressure container;

[0084] Solenoid valve: used to actually adjust the pressure in the high-pressure container according to the control signal.

[0085] Control panel: including display screen and operation interface, used for monitoring and controlling the running state of the system, and setting and adjusting the system parameters;

[0086] Step S402, control the flow of supercritical carbon dioxide by adjusting the flow control valve, adjust the flow and time of supercritical carbon dioxide, the flow size is 5ml / min, the time adjustment range is 65min, in order to fully flush and clean the target hydrate;

[0087] Step S5, extract the supercritical carbon dioxide and the detergent from the stainless steel high-pressure container, separate the hydrate particles and the detergent by high-efficiency centrifuge, and repeat the separation for 4 times;

[0088] Step S6, drying: dry the target hydrate separated from the detergent in an oven for 10 minutes, and the temperature of the oven is set to 60°C, to obtain the supercritical carbon dioxide flushed hydrate.

[0089] Example 3

[0090] The preparation method of the supercritical carbon dioxide flushing hydrate includes the following steps:

[0091] Step S1, preparation:

[0092] Step S101, grinding the target hydrate powder into fine particles, specifically, putting the clean and dry target hydrate powder into the grinding cavity of the ball mill, sieving the powder treated by 5-hour ball milling through a 200-mesh screen, and then drying in a bellows to obtain the target hydrate powder;

[0093] Step S102, preparing supercritical carbon dioxide, ensuring that its purity is higher than 99%, the specific method of preparing supercritical carbon dioxide is to fill liquid carbon dioxide into the high-pressure container of the supercritical carbon dioxide equipment, use a temperature controller to heat the liquid carbon dioxide in the high-pressure container to reach the supercritical state; at the same time, use the combination of pressure sensor and pressure regulator to control the pressure in the container to reach the supercritical point;

[0094] Storage and purification, transfer the supercritical carbon dioxide to the storage container, and use activated carbon adsorption and molecular sieve treatment to remove residual impurities and impurities;

[0095] Purity analysis, use a gas chromatograph to analyze the supercritical carbon dioxide;

[0096] Step S103, clean the stainless steel high-pressure container and ensure its good sealing performance, the specific steps of cleaning the stainless steel high-pressure container are: use a mixture of warm water and soap to wipe the surface with a soft cloth or sponge, which is suitable for general dirt and grease, then use diluted bleach and gently wipe the stainless steel surface with a brush;

[0097] Step S104, prepare the detergent, use the detergent to remove impurities on the surface of the target hydrate, the detergent is diethyl ether;

[0098] Step S2, loading work: put the ground target hydrate particles into the stainless steel high-pressure container, and add the detergent to clean the target hydrate;

[0099] Step S3, close the container, tightly close the stainless steel high-pressure container and ensure that there is no leakage at the sealing part;

[0100] Step S4, supercritical carbon dioxide flushing, specifically including the following steps:

[0101] Step S401, control the temperature and pressure of the stainless steel high-pressure container containing the target hydrate and the detergent, the temperature is between 100 degrees Celsius, and the pressure is 5 MPa, so that supercritical carbon dioxide enters the stainless steel high-pressure container, and in the supercritical state, the carbon dioxide wraps the hydrate particles, thereby dissolving and cleaning the impurities therein; when controlling the temperature, the stainless steel container is placed in a constant temperature tank, and the pressure is controlled by an electronic pressure control system.

[0102] Among them, the electronic pressure control system includes:

[0103] Pressure sensor: used for direct measurement of pressure change in high-pressure container and conversion into electrical signal;

[0104] PLC controller: used for controlling the pressure in the high-pressure container;

[0105] Proportional valve: adjusts the flow of fluid or gas according to the control signal, thereby controlling the pressure in the high-pressure container;

[0106] Solenoid valve: used to actually adjust the pressure in the high-pressure container according to the control signal.

[0107] Control panel: including display screen and operation interface, used for monitoring and controlling the running state of the system, and setting and adjusting the system parameters;

[0108] Step S402, control the flow of supercritical carbon dioxide by adjusting the flow control valve, adjust the flow and time of supercritical carbon dioxide, the flow size is 10 ml / min, the time adjustment range is 100 min, in order to fully flush and clean the target hydrate;

[0109] Step S5, extract supercritical carbon dioxide and detergent from the stainless steel high-pressure container, separate hydrate particles and detergent by high-efficiency centrifuge, repeat separation 5 times;

[0110] Step S6, drying: the target hydrate separated from the detergent is dried in an oven for 20 min, the temperature of the oven is set to 80℃, and the supercritical carbon dioxide flushed hydrate is obtained.

[0111] Example 4

[0112] The difference between this embodiment and example 1 is that the detergent is isopropyl ether.

[0113] The use of supercritical carbon dioxide in the present application can perform the hydration flushing at a lower temperature, avoiding the damage to the structure of the target substance caused by high temperature in the traditional method. Supercritical carbon dioxide is an environmentally friendly solvent, which does not produce harmful substances during preparation and can be recycled. Supercritical carbon dioxide has high permeability and solubility in the supercritical state, which can fully flush and clean the impurities in the target hydrate, improving its purity. The physical properties of supercritical carbon dioxide can realize a rapid and controllable hydration flushing process by adjusting the temperature and pressure, improving the preparation efficiency and product quality. The preparation method is suitable for various types of hydrates and can be applied in laboratory and industrial production.

[0114] The above specific embodiments are only several optional embodiments of the present application, and based on the technical solutions of the present application and the related inspirations of the above embodiments, those skilled in the art can make various alternative improvements and combinations on the above specific embodiments.

Claims

1. A method for the production of supercritical carbon dioxide purged hydrates, characterized in that, The method comprises the following steps: Step S1, preparation: Step S101, grinding the target hydrate powder into fine particles; Step S102, preparing supercritical carbon dioxide, ensuring that its purity is higher than 99%; Step S103, cleaning the stainless steel high-pressure container and ensuring that its sealing performance is good; Step S104, preparing a detergent, and using the detergent to remove impurities on the surface of the target hydrate; Step S2, loading work: putting the ground target hydrate particles into the stainless steel high-pressure container, and adding the detergent to clean the target hydrate; Step S3, closing the container, tightly closing the stainless steel high-pressure container, and ensuring that there is no leakage at the sealing position; Step S4, supercritical carbon dioxide flushing, specifically comprising the following steps: Step S401, controlling the temperature and pressure of the stainless steel high-pressure container containing the target hydrate and the detergent, the temperature is between 40-100 degrees Celsius, and the pressure is 1-5 MPa, so that the supercritical carbon dioxide enters the stainless steel high-pressure container, and the carbon dioxide wraps the hydrate particles in the supercritical state; Step S402, controlling the flow of supercritical carbon dioxide by adjusting the flow control valve, adjusting the flow and time of supercritical carbon dioxide, the flow size is 1-10 ml / min, and the time adjustment range is 30-100 min, so as to fully flush and clean the target hydrate; Step S5, extracting the supercritical carbon dioxide and the detergent from the stainless steel high-pressure container, separating the hydrate particles and the detergent by using a high-efficiency centrifuge, and repeating the separation for 3-5 times; Step S6, drying: drying the target hydrate separated from the detergent in an oven for 1-20 min to obtain the supercritical carbon dioxide flushed hydrate.

2. The method for preparing supercritical carbon dioxide bubbling hydrate according to claim 1, characterized in that, In the step S101, the target hydrate powder is ground into fine particles, specifically, the clean and dry target hydrate powder is put into the grinding cavity of the ball mill, the powder treated by ball milling for 3-5 hours is passed through a 200-mesh screen, and then the target hydrate powder is obtained by drying in a bellows.

3. The method of claim 1, wherein the supercritical carbon dioxide is at a pressure of 1000 to 3000 psi and a temperature of 40 to 120 °C. The detergent is any one of propyl alcohol, butyl alcohol, diethyl ether, and isopropyl ether.

4. The method for preparing supercritical carbon dioxide bubbling hydrate according to claim 1, characterized in that, In the step S102, the specific method for preparing supercritical carbon dioxide is to fill liquid carbon dioxide into the high-pressure container of the supercritical carbon dioxide equipment, use a temperature controller to heat the liquid carbon dioxide in the high-pressure container to make it reach the supercritical state, and use a combination of a pressure sensor and a pressure regulator to control the pressure in the container to make it reach the supercritical point.

5. The method for preparing supercritical carbon dioxide bubbling hydrate according to claim 4, characterized in that, In the step S102, it further comprises: Storage and purification: transferring the supercritical carbon dioxide to a storage container, and removing residual impurities and impurities by using activated carbon adsorption and molecular sieve treatment; Analyzing the purity by using a gas chromatograph to analyze the supercritical carbon dioxide.

6. The method of claim 1, wherein the supercritical carbon dioxide is at a pressure of 1000 to 3000 psi and a temperature of 40 to 120 °C. The specific steps for cleaning the stainless steel high-pressure container are: using a mixture of warm water and a neutral cleaner to wipe the surface with a soft cloth or sponge, then using diluted bleach, and gently wiping the stainless steel surface with a brush.

7. The method of claim 1, wherein the supercritical carbon dioxide is at a pressure of 1000 to 3000 psi and a temperature of 40 to 120 °C. In the step S401, the temperature is controlled by placing the stainless steel container in a constant temperature tank, and the pressure is controlled by using an electronic pressure control system.

8. The method of claim 7, wherein the supercritical carbon dioxide is at a pressure of 1000 to 3000 psi and a temperature of 40 to 120 °C. The electronic pressure control system comprises: Pressure sensor: used to directly measure the pressure change in the high-pressure container and convert it into an electrical signal; PLC controller: used to control the pressure in the high-pressure container; Proportional valve: adjusts the flow of fluid or gas according to the control signal, thereby controlling the pressure in the high-pressure container; Solenoid valve: used to actually adjust the pressure in the high-pressure container according to the control signal; Control panel: includes a display screen and an operation interface, used to monitor and control the running state of the system, and set and adjust the system parameters.

9. The method for preparing supercritical carbon dioxide bubbling hydrate according to claim 1, characterized in that, In step S6, the temperature of the oven is set to 40-80℃.