Gas hydrate generation accelerant as well as preparation method and application thereof

Abstract

The invention relates to the technical field of gas hydrate generation and carbon dioxide capture and storage, and discloses a gas hydrate generation accelerant as well as a preparation method and application thereof. The gas hydrate generation accelerant is prepared from water, sucralose and graphene oxide dispersion liquid. According to the gas hydrate generation accelerant provided by the invention, sucralose and graphene oxide dispersion liquid are used, so that the surface tension of a solution can be effectively reduced, the gas consumption in the hydrate generation process is improved, and the induction time of hydrate generation is shortened and the generation efficiency is improved by strengthening the heat transfer and mass transfer processes in the hydrate generation process; efficient capture and storage of carbon dioxide are realized, and a wide prospect is provided for practical application of capture and storage of carbon dioxide by a hydrate technology.

Description

Technical Field

[0001] The present invention relates to the technical field of gas hydrate formation and carbon dioxide capture and storage, in particular to a gas hydrate formation promoter, a preparation method and application thereof. Background Art

[0002] The greenhouse effect and other environmental pollution problems caused by excessive combustion of traditional fossil fuels such as coal and oil have prompted people to continuously explore alternative clean energy and conduct in-depth research on carbon capture technology. At present, fossil fuels still dominate energy use worldwide. Therefore, carbon capture technology is one of the most promising technologies for reducing carbon emissions.

[0003] As the greenhouse effect continues to intensify, people are paying more and more attention to the application of hydrate capture technology in the field of carbon dioxide capture and storage. Hydrate CO2 capture technology refers to a special complex compound formed by CO2 and water under a certain temperature and pressure. Compared with other technologies, the use of hydrates to capture and store CO2 has the advantages of high separation efficiency (especially in the case of complex components), environmental friendliness, and low cost. However, due to the slow generation rate and low gas storage capacity in the hydrate formation process, the application of hydrate technology is limited.

[0004] Traditional hydrate promoters (such as sodium dodecyl sulfate SDS) have problems such as high toxicity and excessive foaming, and it is difficult for a single additive to balance high efficiency and environmental protection. Although sucralose can reduce surface tension, its use alone will prolong the induction time due to covering the nucleation sites. Although graphene oxide can provide nucleation sites, it is easy to agglomerate in excess. The prior art does not disclose a synergistic solution for the combination of the two. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies in the prior art and provide a gas hydrate formation promoter and its preparation method and application. The present invention uses sucralose and graphene oxide to reduce the induction time of hydrate formation, promote the formation of hydrates, and solve the current problems of slow hydrate formation speed, low gas consumption, and long overall hydrate formation time.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] A gas hydrate formation promoter comprises the following components in percentage by mass:

[0008] Sucralose 0.4~1.5wt%

[0009] Graphene oxide dispersion 0.0075~0.0275wt%

[0010] Water balance.

[0011] Among the above-mentioned gas hydrate formation promoters, sucralose contains hydrophobic chloro groups and hydrophilic hydroxyl groups, making sucralose amphiphilic. The hydrophobic chloro groups face the gas phase, and the hydrophilic hydroxyl groups extend into the aqueous phase. This arrangement weakens the hydrogen bond network between water molecules, can effectively reduce the surface tension of the solution, promote the entry of the gas phase into the liquid phase, and increase the gas consumption during the hydrate formation process.

[0012] Although sucralose can effectively increase the gas consumption during the hydrate formation process, the directional arrangement of its chloro groups and hydroxyl groups at the gas-liquid interface easily covers the nucleation sites at the gas-liquid interface, resulting in an extended induction time for hydrate formation. In the present invention, the phenomenon of the relatively long induction time of sucralose is improved by adding a graphene oxide dispersion.

[0013] The hydroxyl groups in sucralose can form hydrogen bonds with the hydroxyl groups and carboxyl groups in graphene oxide. The special structure of sucralose can reduce the hydrogen bond competition between graphene oxide and water molecules. In addition, the chloro groups in sucralose and the unoxidized regions in graphene oxide can provide spatial orientation for their combination through hydrophobic effects, and the formed hydrophobic region enables exclusive binding between sucralose and graphene oxide through hydrogen bonds.

[0014] In the present invention, through the synergistic effect of sucralose and graphene oxide dispersion, by increasing the gas-liquid contact area, providing nucleation sites for hydrate formation, and optimizing the hydrogen bond network required for hydrate formation, the problem of the relatively long induction time for hydrate formation in the sucralose solution is fundamentally solved.

[0015] In addition, the hydroxyl groups and carboxyl groups in graphene oxide combine with the hydroxyl groups in sucralose through hydrogen bonds, causing sucralose to adsorb on the surface of graphene oxide. When the hydrogen bonds between the hydroxyl groups on sucralose and water molecules are broken, water molecules can promptly combine with the hydroxyl groups and carboxyl groups on graphene oxide to form a dense and ordered hydrogen bond network, thus improving the problem that the hydrogen bonds between sucralose and water molecules are easily broken and it is difficult to form a dense and ordered hydrogen bond network.

[0016] Sucralose is directionally arranged at the gas-liquid interface, which can promote the entry of the gas phase into the liquid phase but also cover the nucleation sites at the gas-liquid interface. The abundant oxygen-containing groups in graphene oxide can effectively improve the mass transfer efficiency of the entering gas phase in the liquid phase, and its large specific surface area can also provide abundant nucleation sites for hydrate nucleation, solving the problem of sucralose covering the nucleation sites.

[0017] As a nanomaterial, graphene oxide has good thermal conductivity and can effectively weaken the influence of the heat generated during the hydrate formation process on the continuous formation of hydrates.

[0018] The mass percentage of sucralose is 0.4 - 1.5 wt%. When the concentration of sucralose is too high, it will lead to an increase in the viscosity of the solution and an increase in the gas diffusion resistance.

[0019] The mass percentage of the graphene oxide dispersion is 0.0075 - 0.0275 wt%. When the content of graphene oxide in the solution is relatively high, an agglomeration effect is likely to occur. At this time, only a small amount of gas phase can enter the water phase, and during the hydrate nucleation stage, excessive graphene oxide is likely to contact the metastable crystal nuclei, affecting the effect of graphene oxide in promoting hydrate nucleation.

[0020] Furthermore, the purity of the sucralose is greater than 98%.

[0021] Furthermore, the purity of the graphene oxide dispersion is 2 mg / ml. The monolayer rate of graphene oxide contained in the graphene oxide dispersion > 98%, the thickness is 0.6 - 1.0 nm, the sheet diameter is 0.5 - 5 μm, and the specific surface area > 500 m 2 / g.

[0022] A preparation method of a gas hydrate formation promoter as described above specifically includes the following steps:

[0023] Step S1: Weigh the materials with the above mass percentages;

[0024] Step S2: Dissolve sucralose in water to obtain mother liquor A;

[0025] Step S3: Add the graphene oxide dispersion to mother liquor A;

[0026] Step S4: Perform stirring, ultrasonic treatment, and centrifugation in sequence to fully disperse the graphene oxide and obtain the finished promoter.

[0027] Furthermore, in step S4, the stirring operation is specifically: stirring at 600 - 1000 rpm for 30 - 50 min; the ultrasonic operation is specifically: ultrasonic treatment for 20 - 30 min; the centrifugation treatment operation is specifically: centrifuging at 3000 - 5000 rpm for 5 minutes and then taking the supernatant.

[0028] Furthermore, the application of the gas hydrate formation promoter in the formation of carbon dioxide hydrate.

[0029] Furthermore, the application is specifically: injecting the gas hydrate formation promoter into the reaction kettle, with the temperature at 274.15 - 289.15 K, injecting CO2 gas into the reaction kettle until the pressure is 3.5 - 4.5 MPa, and starting magnetic stirring for reaction to obtain a solid hydrate with a high gas storage density.

[0030] Furthermore, the magnetic stirring rate is 615 rpm, and the reaction time is 6 - 10 h.

[0031] The specific operation steps are as follows:

[0032] Inject the prepared gas hydrate formation promoter into the high-pressure reactor through the liquid inlet valve. Turn on the circulating water bath device, connect the high-pressure reactor to the circulating water bath device and set the experimental temperature. Turn on the data collector and the computer, and set the time interval for recording the temperature and pressure changes in the high-pressure reactor. When the temperature in the reactor reaches the experimental temperature, open the high-pressure gas cylinder to allow the required gas to enter the high-pressure reactor through the pressure reducing valve and the inlet valve in sequence. Turn on the magnetic stirrer to achieve gas-liquid dissolution equilibrium in the high-pressure reactor. When the temperature and pressure in the high-pressure reactor reach the required experimental temperature and pressure, cool down the high-pressure reactor through the circulating water bath device. Observe the appearance of hydrate nuclei through the viewing window, and record the experimental data through the data collector and the computer. After the experiment, open the gas outlet valve to discharge the gas, and open the liquid outlet valve to drain the solution into the liquid storage tank.

[0033] The beneficial effects of the present invention are as follows: The present invention is reasonably designed and has a simple preparation method, with the following advantages:

[0034] (1). The gas hydrate formation promoter prepared by the present invention utilizes the amphiphilicity of sucralose to effectively reduce the surface tension of the solution, promote more gas phase to enter the liquid phase, and improve the gas storage capacity during the hydrate formation process;

[0035] (2). The gas hydrate formation promoter prepared by the present invention utilizes the combination of sucralose and graphene oxide through hydrogen bonds. The added graphene oxide can provide abundant nucleation sites for hydrate formation, form a stable and ordered hydrogen bond network with water molecules, and reduce the induction time of hydrate formation;

[0036] (3). Compared with traditional surfactants (such as sodium dodecyl sulfate SDS), sucralose is non-toxic, biodegradable, and produces no foam during use, being green and efficient;

[0037] (4). The gas hydrate formation promoter prepared by the present invention can promote more gas phase to enter the liquid phase, improve the mass transfer efficiency of the gas phase in the liquid phase, and can also timely export the heat generated during the hydrate formation process, maintain the temperature stability in the reactor, and improve the hydrate formation efficiency. Description of the Drawings

[0038] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0039] Figure 1 It is a schematic diagram of the chemical structural formula of sucralose. Specific Embodiments

[0040] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs.

[0041] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular forms also include the plural forms. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0042] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0043] A gas hydrate formation promoter, comprising components in the following mass percentages:

[0044] Sucralose 0.4 - 1.5 wt%

[0045] Graphene oxide dispersion 0.0075 - 0.0275 wt%

[0046] Water the balance.

[0047] Among them, the purity of sucralose is greater than 98%; the purity of the graphene oxide dispersion is 2 mg / ml, the monolayer rate of graphene oxide contained in the graphene oxide dispersion > 98%, the thickness is 0.6 - 1.0 nm, the sheet diameter is 0.5 - 5 μm, and the specific surface area > 500 m 2 / g.

[0048] The chemical structural formula of sucralose is as Figure 1 shown.

[0049] The preparation method of the above-mentioned gas hydrate formation promoter specifically includes the following steps:

[0050] Step S1: Weigh the materials in the above mass percentages;

[0051] Step S2: Dissolve sucralose in water to obtain mother liquor A;

[0052] Step S3: Add graphene oxide dispersion into mother liquor A;

[0053] Step S4: Stir, perform ultrasonic treatment, and centrifuge in sequence to fully disperse graphene oxide and obtain the finished promoter.

[0054] In step S4, the specific stirring operation is: stir at 600 - 1000 rpm for 30 - 50 min; the specific ultrasonic operation is: perform ultrasonic treatment for 20 - 30 min; the specific centrifugation operation is: centrifuge at 3000 - 5000 rpm for 5 minutes and then take the supernatant.

[0055] The application of the above gas hydrate formation promoter, and the application of the gas hydrate formation promoter in the formation of carbon dioxide hydrate.

[0056] The specific application is as follows: Inject the gas hydrate formation promoter into the reaction kettle. When the temperature is 274.15 - 289.15 K, inject CO2 gas into the reaction kettle until the pressure is 3.5 - 4.5 MPa, and start magnetic stirring for reaction to obtain a solid hydrate with a high gas storage density. The magnetic stirring rate is 615 rpm, and the reaction time is 6 - 10 h.

[0057] Example 1

[0058] A preparation method of a gas hydrate formation promoter specifically includes the following steps:

[0059] Step S1: Weigh sucralose, graphene oxide dispersion, and deionized water respectively according to the ratio of 0.4 wt%, 0.0075 wt%, and 99.5925 wt% using an electronic balance;

[0060] Step S2: Dissolve sucralose in deionized water to prepare mother liquor A;

[0061] Step S3: Add graphene oxide dispersion into mother liquor A;

[0062] Step S4: Use a magnetic stirrer to stir at a speed of 800 rpm for 40 min. The stirred liquid is dispersed by ultrasonic treatment for 25 min. The dispersed liquid is centrifuged at a speed of 4000 rpm for 5 minutes using a centrifuge, and then the supernatant is taken as the required solution. The prepared solution is sealed for later use.

[0063] Perform an application experiment on the gas hydrate formation promoter prepared in this example, specifically as follows:

[0064] This application experiment was carried out in a high-pressure reactor with a volume of 250 mL, and the gas selected by the laboratory was carbon dioxide. Before the experiment, the high-pressure reactor was repeatedly cleaned with deionized water and ethanol reagents at least three times, and then the high-pressure reactor was purged with gas to remove the excess gas in the high-pressure reactor. And the airtightness was checked with soapy water. If no bubbles appeared, it proved that the airtightness was good. Then the prepared solution was injected into the high-pressure reactor, and the high-pressure reactor was connected to a circulating water bath device. After completion, the data acquisition system and the circulating water bath device were turned on, and the temperature and pressure change data were recorded every 2 s. When the temperature in the high-pressure reactor reached 289.15 K, CO2 gas was injected, and then the magnetic stirrer was started at a speed of 615 rpm. When the gas reached the dissolution equilibrium, at this time, the temperature in the high-pressure reactor was stable at 289.15 K and the pressure was stable at 4 Mpa, the temperature in the high-pressure reactor was decreased to the set temperature of 274.35 K at a rate of 0.15 K / min to generate hydrate. After 15.33 min, the appearance of hydrate crystal nuclei was observed in the viewing window.

[0065] Example 2

[0066] A preparation method of a gas hydrate formation promoter specifically includes the following steps:

[0067] Step S1: Weigh sucralose, graphene oxide dispersion and deionized water respectively according to the ratio of 0.6 wt%, 0.0125 wt%, and 99.3875 wt% with an electronic balance;

[0068] Step S2: Dissolve sucralose in deionized water to prepare mother liquor A;

[0069] Step S3: Add graphene oxide dispersion to mother liquor A;

[0070] Step S4: Stir with a magnetic stirrer at a speed of 800 rpm for 40 min. The stirred liquid is dispersed by ultrasonic waves for 25 min. After centrifuging the dispersed liquid at a speed of 4000 rpm for 5 min, the supernatant is taken as the required solution, and the prepared solution is sealed for later use.

[0071] The gas hydrate formation promoter prepared in this example was subjected to an application experiment, specifically as follows:

[0072] This application experiment was carried out in a high-pressure reactor with a volume of 250 mL, and the gas selected in the laboratory was carbon dioxide. Before the experiment, the high-pressure reactor was repeatedly cleaned with deionized water and ethanol reagent at least three times, and then the high-pressure reactor was purged with gas to remove the excess gas in the high-pressure reactor. And the airtightness was tested with soapy water. If no bubbles appeared, it proved that the airtightness was good. Then the prepared solution was injected into the high-pressure reactor, and the high-pressure reactor was connected to the circulating water bath device. After completion, the data acquisition system and the circulating water bath device were turned on, and the temperature and pressure change data were recorded every 2 s. When the temperature in the high-pressure reactor reached 289.15 K, CO2 gas was injected, and then the magnetic stirrer was started at a speed of 615 rpm. When the gas reached the dissolution equilibrium, at this time, the temperature in the high-pressure reactor was stable at 289.15 K and the pressure was stable at 4 Mpa, the temperature in the high-pressure reactor was decreased to the set temperature of 274.35 K at a rate of 0.15 K / min to generate hydrates. After 12.30 min, the appearance of hydrate nuclei was observed in the viewing window.

[0073] Example 3

[0074] A preparation method of a gas hydrate formation promoter specifically includes the following steps:

[0075] Step S1: Weigh sucralose, graphene oxide dispersion and deionized water respectively according to the ratios of 0.6 wt%, 0.0175 wt%, and 98.3825 wt% with an electronic balance;

[0076] Step S2: Dissolve sucralose in deionized water to prepare mother liquor A;

[0077] Step S3: Add graphene oxide dispersion to mother liquor A;

[0078] Step S4: Stir with a magnetic stirrer at a speed of 800 rpm for 40 min. The stirred liquid is dispersed by ultrasonic waves for 25 min. After centrifuging the dispersed liquid at a speed of 4000 rpm for 5 min, the supernatant is taken as the required solution, and the prepared solution is sealed for use.

[0079] The gas hydrate formation promoter prepared in this example was used in an application experiment, specifically as follows:

[0080] This application experiment was carried out in a high-pressure reactor with a volume of 250 mL, and the gas selected in the laboratory was carbon dioxide. Before the experiment, the high-pressure reactor was repeatedly cleaned with deionized water and ethanol reagents at least three times, and then purged with gas to remove the excess gas in the high-pressure reactor. And the airtightness was checked with soapy water. If no bubbles appeared, it proved that the airtightness was good. Then the prepared solution was injected into the high-pressure reactor, and the high-pressure reactor was connected to a circulating water bath device. After completion, the data acquisition system and the circulating water bath device were turned on, and the temperature and pressure change data were recorded every 2 s. When the temperature in the high-pressure reactor reached 289.15 K, CO2 gas was injected, and then the magnetic stirrer was started at a speed of 615 rpm. When the gas reached the dissolution equilibrium, and the temperature in the high-pressure reactor was stable at 289.15 K and the pressure was stable at 4 Mpa, the temperature in the high-pressure reactor was decreased to the set temperature of 274.35 K at a rate of 0.15 K / min to form hydrates. After 5.76 min, the appearance of hydrate nuclei was observed in the viewing window.

[0081] Example 4

[0082] A preparation method of a gas hydrate formation promoter specifically includes the following steps:

[0083] Step S1: Weigh sucralose, graphene oxide dispersion and deionized water respectively according to the ratio of 0.8 wt%, 0.0175 wt%, and 99.1825 wt% with an electronic balance;

[0084] Step S2: Dissolve sucralose in deionized water to prepare mother liquor A;

[0085] Step S3: Add graphene oxide dispersion to mother liquor A;

[0086] Step S4: Stir with a magnetic stirrer at a speed of 800 rpm for 40 min. The stirred liquid is dispersed by ultrasonic waves for 25 min. After centrifuging the dispersed liquid at a speed of 4000 rpm for 5 min, the supernatant is taken as the required solution, and the prepared solution is encapsulated for use.

[0087] The gas hydrate formation promoter prepared in this example was subjected to an application experiment, specifically as follows:

[0088] This application experiment was carried out in a high-pressure reactor with a volume of 250 mL, and the gas selected by the laboratory was carbon dioxide. Before the experiment, the high-pressure reactor was repeatedly cleaned with deionized water and ethanol reagents at least three times, and then the high-pressure reactor was purged with gas to remove the excess gas in the high-pressure reactor. And the airtightness was tested with soapy water. If no bubbles appeared, it proved that the airtightness was good. Then the prepared solution was injected into the high-pressure reactor, and the high-pressure reactor was connected to a circulating water bath device. After completion, the data acquisition system and the circulating water bath device were turned on, and the temperature and pressure change data were recorded every 2 s. When the temperature in the high-pressure reactor reached 289.15 K, CO2 gas was injected, and then magnetic stirring was started at a speed of 615 rpm. When the gas reached the dissolution equilibrium, at this time, the temperature in the high-pressure reactor was stable at 289.15 K and the pressure was stable at 4 Mpa, the temperature in the high-pressure reactor was decreased to the set temperature of 274.35 K at a rate of 0.15 K / min to generate hydrate. After 4.73 min, the appearance of hydrate nuclei was observed in the viewing window.

[0089] Example 5

[0090] A preparation method of a gas hydrate formation promoter specifically includes the following steps:

[0091] Step S1: Weigh sucralose, graphene oxide dispersion and deionized water respectively according to the ratio of 0.8 wt%, 0.0225 wt%, and 99.1775 wt% with an electronic balance;

[0092] Step S2: Dissolve sucralose in deionized water to prepare mother liquor A;

[0093] Step S3: Add graphene oxide dispersion to mother liquor A;

[0094] Step S4: Stir with a magnetic stirrer at a speed of 800 rpm for 40 min. The stirred liquid is dispersed by ultrasonic waves for 25 min. After centrifuging the dispersed liquid at a speed of 4000 rpm for 5 min, the supernatant is taken as the required solution, and the prepared solution is sealed for later use.

[0095] The gas hydrate formation promoter prepared in this example was subjected to an application experiment, specifically as follows:

[0096] This application experiment was carried out in a high-pressure reactor with a volume of 250 mL, and the gas selected in the laboratory was carbon dioxide. Before the experiment, the high-pressure reactor was repeatedly cleaned with deionized water and ethanol reagents at least three times, and then the high-pressure reactor was purged with gas to remove the excess gas in the high-pressure reactor. And the airtightness was checked with soapy water. If no bubbles appeared, it proved that the airtightness was good. Then the prepared solution was injected into the high-pressure reactor, and the high-pressure reactor was connected to a circulating water bath device. After completion, the data acquisition system and the circulating water bath device were turned on, and the temperature and pressure change data were recorded every 2 s. When the temperature in the high-pressure reactor reached 289.15 K, CO2 gas was injected, and then magnetic stirring was started at a speed of 615 rpm. When the gas reached dissolution equilibrium, and the temperature in the high-pressure reactor was stable at 289.15 K and the pressure was stable at 4 Mpa, the temperature in the high-pressure reactor was decreased to the set temperature of 274.35 K at a rate of 0.15 K / min to form hydrates. After 6.77 min, the appearance of hydrate nuclei was observed in the viewing window.

[0097] Example 6

[0098] A preparation method of a gas hydrate formation promoter specifically includes the following steps:

[0099] Step S1: Weigh sucralose, graphene oxide dispersion and deionized water respectively according to the ratio of 1.0 wt%, 0.0175 wt%, and 98.9825 wt% with an electronic balance;

[0100] Step S2: Dissolve sucralose in deionized water to prepare mother liquor A;

[0101] Step S3: Add graphene oxide dispersion to mother liquor A;

[0102] Step S4: Stir with a magnetic stirrer at a speed of 800 rpm for 40 min. The stirred liquid is dispersed by ultrasonic waves for 25 min. After centrifuging the dispersed liquid at a speed of 4000 rpm for 5 min, the supernatant is taken as the required solution, and the prepared solution is encapsulated for use.

[0103] The gas hydrate formation promoter prepared in this example was used in an application experiment, which is specifically as follows:

[0104] This application experiment was carried out in a high-pressure reactor with a volume of 250 mL, and the gas selected in the laboratory was carbon dioxide. Before the experiment, the high-pressure reactor was repeatedly cleaned with deionized water and ethanol reagents at least three times, and then the high-pressure reactor was purged with gas to remove the excess gas in the high-pressure reactor. And the airtightness was checked with soapy water. If no bubbles appeared, it proved that the airtightness was good. Then the prepared solution was injected into the high-pressure reactor, and the high-pressure reactor was connected to a circulating water bath device. After completion, the data acquisition system and the circulating water bath device were turned on, and the temperature and pressure change data were recorded every 2 s. When the temperature in the high-pressure reactor reached 289.15 K, CO2 gas was injected, and then the magnetic stirrer was started at a speed of 615 rpm. When the gas reached the dissolution equilibrium, at this time, the temperature in the high-pressure reactor was stable at 289.15 K and the pressure was stable at 4 Mpa, the temperature in the high-pressure reactor was decreased to the set temperature of 274.35 K at a rate of 0.15 K / min to generate hydrates. After 9.9 min, the appearance of hydrate nuclei was observed in the viewing window.

[0105] Example 7

[0106] A preparation method of a gas hydrate formation promoter specifically includes the following steps:

[0107] Step S1: Weigh sucralose, graphene oxide dispersion and deionized water respectively according to the ratio of 1.0 wt%, 0.0225 wt%, and 98.9775 wt% with an electronic balance;

[0108] Step S2: Dissolve sucralose in deionized water to prepare mother liquor A;

[0109] Step S3: Add graphene oxide dispersion to mother liquor A;

[0110] Step S4: Stir with a magnetic stirrer at a speed of 800 rpm for 40 min. The stirred liquid is dispersed by ultrasonic waves for 25 min. After centrifuging the dispersed liquid at a speed of 4000 rpm for 5 min, the supernatant is taken as the required solution, and the prepared solution is sealed for later use.

[0111] The gas hydrate formation promoter prepared in this example was used in an application experiment, specifically as follows:

[0112] This application experiment was carried out in a high-pressure reactor with a volume of 250 mL, and the gas selected in the laboratory was carbon dioxide. Before the experiment, the high-pressure reactor was repeatedly cleaned with deionized water and ethanol reagents at least three times, and then purged with gas to remove the excess gas in the high-pressure reactor. And the airtightness was tested with soapy water. If no bubbles appeared, it proved that the airtightness was good. Then the prepared solution was injected into the high-pressure reactor, and the high-pressure reactor was connected to a circulating water bath device. After completion, the data acquisition system and the circulating water bath device were turned on, and the temperature and pressure change data were recorded every 2 s. When the temperature in the high-pressure reactor reached 289.15 K, CO2 gas was injected, and then the magnetic stirrer was started at a speed of 615 rpm. When the gas reached the dissolution equilibrium, at this time, the temperature in the high-pressure reactor was stable at 289.15 K and the pressure was stable at 4 Mpa, the temperature in the high-pressure reactor was decreased to the set temperature of 274.35 K at a rate of 0.15 K / min to generate hydrates. After 14.93 min, the appearance of hydrate nuclei was observed in the viewing window.

[0113] Example 8

[0114] A preparation method of a gas hydrate formation promoter specifically includes the following steps:

[0115] Step S1: Weigh sucralose, graphene oxide dispersion and deionized water respectively with an electronic balance according to the ratio of 1.5 wt%, 0.0275 wt%, and 98.4725 wt%;

[0116] Step S2: Dissolve sucralose in deionized water to prepare mother liquor A;

[0117] Step S3: Add graphene oxide dispersion to mother liquor A;

[0118] Step S4: Stir with a magnetic stirrer at a speed of 800 rpm for 40 min. The stirred liquid is dispersed by ultrasonic waves for 25 min. After centrifuging the dispersed liquid at a speed of 4000 rpm for 5 min, the supernatant is taken as the required solution, and the prepared solution is encapsulated for use.

[0119] The gas hydrate formation promoter prepared in this example was subjected to an application experiment, specifically as follows:

[0120] This application experiment was carried out in a high-pressure reactor with a volume of 250 mL, and the gas selected in the laboratory was carbon dioxide. Before the experiment, the high-pressure reactor was repeatedly washed with deionized water and ethanol reagent at least three times, and then purged with gas to remove the excess gas in the high-pressure reactor. And the airtightness was checked with soapy water. If no bubbles appeared, it proved that the airtightness was good. Then the prepared solution was injected into the high-pressure reactor, and the high-pressure reactor was connected to a circulating water bath device. After completion, the data acquisition system and the circulating water bath device were turned on, and the temperature and pressure change data were recorded every 2 s. When the temperature in the high-pressure reactor reached 289.15 K, CO2 gas was injected, and then the magnetic stirring was started at a speed of 615 rpm. When the gas reached the dissolution equilibrium, at this time, the temperature in the high-pressure reactor was stable at 289.15 K and the pressure was stable at 4 Mpa, the temperature in the high-pressure reactor was decreased to the set temperature of 274.35 K at a rate of 0.15 K / min to form hydrate. After 18.7 min, the appearance of hydrate nuclei was observed in the viewing window.

[0121] Comparative Example 1

[0122] In this comparative example, no promoter was used for the application experiment, and the specific steps are as follows:

[0123] This application experiment was carried out in a high-pressure reactor with a volume of 250 mL, and the gas selected in the laboratory was carbon dioxide. Before the experiment, the high-pressure reactor was repeatedly washed with deionized water and ethanol reagent at least three times, and then purged with gas to remove the excess gas in the high-pressure reactor. And the airtightness was checked with soapy water. If no bubbles appeared, it proved that the airtightness was good. Then the pure aqueous solution was injected into the high-pressure reactor, and the high-pressure reactor was connected to a circulating water bath device. After completion, the data acquisition system and the circulating water bath device were turned on, and the temperature and pressure change data were recorded every 2 s. When the temperature in the high-pressure reactor reached 289.15 K, CO2 gas was injected, and then the magnetic stirring was started at a speed of 615 rpm. When the gas reached the dissolution equilibrium, at this time, the temperature in the high-pressure reactor was stable at 289.15 K and the pressure was stable at 4 Mpa, the temperature in the high-pressure reactor was decreased to the set temperature of 274.35 K at a rate of 0.15 K / min to form hydrate. After 28.43 min, the appearance of hydrate nuclei was observed in the viewing window.

[0124] Comparative Example 2

[0125] A preparation method of a gas hydrate formation promoter specifically includes the following steps:

[0126] Step S1: Weigh sucralose, graphene oxide dispersion liquid and deionized water according to the ratios of 0.2 wt%, 0.0025 wt%, and 99.7975 wt% respectively with an electronic balance;

[0127] Step S2: Dissolve sucralose in deionized water to prepare mother liquor A;

[0128] Step S3: Add graphene oxide dispersion to mother liquor A;

[0129] Step S4: Stir with a magnetic stirrer at a speed of 800 rpm for 40 min. Disperse the stirred liquid by ultrasound for 25 min. After centrifuging the dispersed liquid at a speed of 4000 rpm for 5 min, take the supernatant as the required solution, and encapsulate the prepared solution for later use.

[0130] Perform an application experiment on the gas hydrate formation promoter prepared in this comparative example as follows:

[0131] This application experiment is carried out in a high-pressure reactor with a volume of 250 mL. The gas selected in the laboratory is carbon dioxide. Before the experiment, repeatedly wash the high-pressure reactor with deionized water and ethanol reagent at least three times, and then purge the high-pressure reactor with gas to remove the excess gas in the high-pressure reactor. And perform a leak inspection operation with soapy water. If no bubbles appear, it proves that the airtightness is good. Then inject the prepared solution into the high-pressure reactor, connect the high-pressure reactor to the circulating water bath device. After completion, turn on the data acquisition system and the circulating water bath device, and set to record the temperature and pressure change data every 2 s. When the temperature in the high-pressure reactor reaches 289.15 K, inject CO2 gas, and then start the magnetic stirrer at a speed of 615 rpm. When the gas reaches the dissolution equilibrium, at this time, the temperature in the high-pressure reactor is stable at 289.15 K and the pressure is stable at 4 Mpa, lower the temperature in the high-pressure reactor at a rate of 0.15 K / min to the set temperature of 274.35 K to generate hydrates. After 16.40 min, the appearance of hydrate nuclei is observed in the viewing window.

[0132] Comparative Example 3

[0133] A preparation method of a gas hydrate formation promoter specifically includes the following steps:

[0134] Step S1: Weigh sucralose, graphene oxide dispersion and deionized water respectively according to the ratio of 2.0 wt%, 0.03 wt%, and 97.97 wt% with an electronic balance;

[0135] Step S2: Dissolve sucralose in deionized water to prepare mother liquor A;

[0136] Step S3: Add graphene oxide dispersion to mother liquor A;

[0137] Step S4: Stir with a magnetic stirrer at a speed of 800 rpm for 40 min. The stirred liquid is dispersed by ultrasonic waves for 25 min. After centrifuging the dispersed liquid at a speed of 4000 rpm for 5 minutes, the supernatant is taken as the required solution. The prepared solution is encapsulated for later use.

[0138] The gas hydrate formation promoter prepared in this comparative example was subjected to an application experiment, which is as follows:

[0139] This application experiment was carried out in a high-pressure reactor with a volume of 250 mL, and the gas selected in the laboratory was carbon dioxide. Before the experiment, the high-pressure reactor was repeatedly cleaned with deionized water and ethanol reagent at least three times, and then purged with gas to remove the excess gas in the high-pressure reactor. And the airtightness was checked with soapy water. If no bubbles appeared, it proved that the airtightness was good. Then the prepared solution was injected into the high-pressure reactor, and the high-pressure reactor was connected to a circulating water bath device. After completion, the data acquisition system and the circulating water bath device were turned on, and the temperature and pressure change data were recorded every 2 s. When the temperature in the high-pressure reactor reached 289.15 K, CO2 gas was injected, and then the magnetic stirrer was started at a speed of 615 rpm. When the gas reached the dissolution equilibrium, at this time, the temperature in the high-pressure reactor was stable at 289.15 K and the pressure was stable at 4 Mpa, the temperature in the high-pressure reactor was decreased at a rate of 0.15 K / min to the set temperature of 274.35 K to form hydrates. After 21.43 min, the appearance of hydrate nuclei was observed in the viewing window.

[0140] The kinetic parameters of the finished products prepared in Examples 1 to 8 and Comparative Examples 1 to 3 were tested, and the test results are shown in Table 1.

[0141] Table 1 Experimental results of Examples 1 to 8 and Comparative Examples 1 to 3

[0142]

[0143] As can be seen from Table 1, the gas hydrate formation promoter prepared from sucralose and graphene oxide can effectively improve the kinetic performance of hydrate formation. Among them, by comparing Comparative Example 2 and Example 3, it is found that increasing the content of graphene oxide at this concentration of sucralose can effectively increase the hydrate nucleation sites, improve the influence of sucralose on the formation of an ordered hydrogen bond network, improve the mass transfer efficiency of the solution, and increase the gas consumption rate and gas consumption. This effect is also reflected in Examples 4 and 5. The difference is that due to the increase in the concentration of graphene oxide, agglomeration effects will occur among graphene oxide molecules in the solution, resulting in a slight decrease in the gas-liquid contact area, affecting the hydrate nucleation sites, and increasing the induction time. In Examples 6 and 7, due to the further increase in the concentration of sucralose, the improvement performance of graphene oxide on sucralose weakens. At this time, increasing the concentration of graphene oxide will also reduce the kinetic performance of the promoter due to the agglomeration effect. In Example 8, due to the further increase in the concentration of sucralose, the solution viscosity increases, and high-concentration graphene oxide is more likely to agglomerate. The combined effect of the two results in a decrease in the kinetic performance of the promoter. Therefore, it can be found that by further increasing the concentrations of the two in Comparative Case 3, the kinetic performance of the hydrate gradually approaches that of pure aqueous solution after adding the promoter. On the contrary, in Example 1 and Comparative Example 2, it is found that due to their low concentrations, their kinetic advantages cannot be fully exerted, and the kinetic performance of the hydrate is also much lower than that of the hydrates in other examples.

[0144] In summary, the gas hydrate formation promoter provided by the present invention uses a dispersion of sucralose and graphene oxide, which can effectively reduce the surface tension of the solution, increase the gas consumption during the hydrate formation process, reduce the induction time of hydrate formation, improve the formation efficiency, and achieve efficient capture and storage of carbon dioxide by strengthening the heat and mass transfer processes during the hydrate formation process, providing a broad prospect for the practical application of hydrate technology for capturing and storing carbon dioxide.

[0145] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A gas hydrate formation promoter, characterized in that: Comprising components in the following mass percentages: Sucralose 0.4 - 1.5 wt% Graphene oxide dispersion 0.0075 - 0.0275 wt% Water the balance.

2. The promoter for gas hydrate formation according to claim 1, wherein: The purity of the sucralose is greater than 98%.

3. The promoter for gas hydrate formation according to claim 1, wherein: The purity of the graphene oxide dispersion is 2 mg / ml. The monolayer ratio of the graphene oxide contained in the graphene oxide dispersion is >98%, the thickness is 0.6 - 1.0 nm, the sheet diameter is 0.5 - 5 μm, and the specific surface area is >500 m 2 / g.

4. A preparation method of a gas hydrate formation promoter according to any one of claims 1 to 3, characterized in that: Specifically, it includes the following steps: Step S1, weigh the materials in the above mass percentages; Step S2, dissolve sucralose in water to obtain mother liquor A; Step S3, add graphene oxide dispersion to mother liquor A; Step S4, perform stirring, ultrasonic treatment and centrifugation in sequence to fully disperse graphene oxide and obtain the finished promoter.

5. The preparation method of a gas hydrate formation promoter according to claim 4, characterized in that: In the said step S4, the stirring operation is specifically: stirring at 600 - 1000 rpm for 30 - 50 min; the ultrasonic operation is specifically: ultrasonic treatment for 20 - 30 min; the centrifugation treatment operation is specifically: centrifuging at 3000 - 5000 rpm for 5 minutes and then taking the supernatant.

6. Use of a gas hydrate formation promoter according to any one of claims 1 to 3, characterized in that: The application of the gas hydrate formation promoter in the formation of carbon dioxide hydrate.

7. Use of a promoter for gas hydrate formation according to claim 6, characterized in that: The said application is specifically: injecting the gas hydrate formation promoter into the reaction kettle, with the temperature at 274.15 - 289.15 K, injecting CO2 gas into the reaction kettle until the pressure is 3.5 - 4.5 MPa, and starting magnetic stirring for reaction to obtain a solid hydrate with a high gas storage density.

8. Use of a gas hydrate formation promoter according to claim 7, characterized in that: The magnetic stirring rate is 615 rpm and the reaction time is 6 - 10 h.

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