CN107955092A - A kind of gas hydrate nanometer accelerating agent of size tunable and preparation method thereof - Google Patents

Abstract

The invention relates to the field of storage and transportation of gas (natural gas, hydrogen, etc.) applied to the hydrate method, and can also be applied to the field of separation of mixed gases by the hydrate method, the field of carbon dioxide sequestration by the hydrate method, and the field of cold storage by the hydrate method. A diameter-controllable gas hydrate nano accelerator and a preparation method thereof. The nano-accelerator is a nano-accelerator obtained by seed soap-free emulsion polymerization of hydrophilic monomers and hydrophobic monomers; wherein, the hydrophilic monomers are sulfonate-type or quaternary ammonium-type comonomers, and the hydrophobic monomers are Styrene and acrylate monomers, the ratio of hydrophilic and hydrophobic monomers is 1:1‑1:10. The nano-accelerator of the invention exhibits excellent recycling performance.

Description

A gas hydrate nano accelerator with controllable particle size and preparation method thereof

technical field

The invention relates to the field of storage and transportation of gas (natural gas, hydrogen, etc.) applied to the hydrate method, and can also be applied to the field of separation of mixed gases by the hydrate method, the field of carbon dioxide sequestration by the hydrate method, and the field of cold storage by the hydrate method. A diameter-controllable gas hydrate nano accelerator and a preparation method thereof.

Background technique

Gas hydrate is a cage-type crystalline compound formed by gas molecules and water molecules at a certain temperature and pressure. Water molecules form a cage-type framework through hydrogen bonds, and gas molecules exist in the cage-type framework through intermolecular forces. Gas hydrate has a high gas storage capacity, which can theoretically achieve 180 times the gas storage capacity, and can be stored stably under milder conditions (for example, -15°C, normal pressure). Therefore, hydrate technology is regarded as It is a gas storage and transportation technology with great application potential. In addition, hydrates can also be used in the separation of mixed gases, carbon dioxide sequestration and cold storage and other fields. However, the long induction period (days or even weeks), slow hydrate growth, and low water conversion rate in the gas hydrate formation process have become obstacles to the application of gas hydrate technology. Therefore, how to realize the rapid formation of gas hydrate is a key to exploiting the technology.

Surfactants have been proven to effectively promote the formation of gas hydrates. Common surfactants, such as sodium dodecylsulfonate and cetyltrimethylammonium bromide, have been proven to be the most effective surface active agents. However, under the conditions of hydrate formation (low temperature and high pressure), surfactants have low solubility and are easy to precipitate; in addition, the use of surfactants will cause a large amount of foam during the decomposition of hydrates, which not only affects the application of hydrates Moreover, it leads to the loss of surfactant, which is not conducive to the recovery and utilization of surfactant, and it is difficult to meet the needs of industrial application of hydrate. Therefore, it is very necessary to prepare a new type of gas hydrate accelerator. At present, some patented technologies for preparing gas hydrate accelerators have been published in China. For example, patents such as CN101514300B, CN103275257B, CN103318890B, CN103663451B, CN104437290A, CN104857891B, and CN104893660A all mention that the mixture of surfactants and other compounds or particles is used as a gas Hydrate accelerator, but only investigated the formation process of hydrate, did not explore the decomposition process of hydrate, and the use of surfactant will inevitably lead to the generation of a large amount of foam in the process of hydrate decomposition, which is not conducive to the recycling of the accelerator , therefore, the preparation of stable and effective accelerators with good cycle performance plays a vital role in the industrial application of hydrates in various fields.

Contents of the invention

Aiming at the problems in the prior art, the present invention provides a gas hydrate nano accelerator with controllable particle size and a preparation method thereof.

In order to achieve the above object, the technical solution adopted by the present invention is:

A gas hydrate nano-accelerator with controllable particle size, the nano-accelerator is a nano-accelerator obtained by seed-free emulsion polymerization of a hydrophilic monomer and a hydrophobic monomer; wherein, the hydrophilic monomer is sulfonic acid Acid-type or quaternary-ammonium-type comonomers, hydrophobic monomers are styrene and acrylate monomers, and the ratio of hydrophilic and hydrophobic monomers is 1:1-1:10.

The structural formula of the sulfonate type hydrophilic monomer is as follows:

In the formula, R is styryl, allyl, methallyl, methacryloyloxyethyl, methacryloyloxypropyl or undecyloxyethyl;

Preferably: the sulfonate-type comonomer is sodium p-styrene sulfonate, sodium allyl sulfonate, sodium methacrylate sulfonate, sodium ethyl methacrylate sulfonate, sodium propyl methacrylate sulfonate or Sodium monoenoic acid ethyl ester sulfonate, etc.;

The structural formula of the quaternary ammonium root type hydrophilic monomer is as follows:

In the formula, R is methacryloyloxyethyl or methacryloyloxyethylbenzyl.

Preferred quaternary ammonium radical comonomers are methacryloyloxyethyl trimethyl ammonium chloride or methacryloyloxyethyl dimethyl benzyl ammonium chloride, etc.;

The hydrophobic comonomers are styrene or acrylate monomers.

Preferred hydrophobic monomers are styrene, methyl acrylate, ethyl acrylate or butyl acrylate, and the like.

Specifically: under the protection of nitrogen, add deionized water, hydrophilic monomers and part of hydrophobic monomers sequentially under stirring conditions, so that the two reaction monomers are evenly mixed; after mixing, the temperature is raised to 70-80 ° C, and then Add the initiator dropwise, react at a constant temperature of 70-80°C for 0.5-1h, then add the remaining hydrophobic monomers dropwise, and connect the hydrophilic functional groups in the hydrophilic monomers with covalent bonds through seed-free emulsion polymerization A gas hydrate nano-accelerator coated with a hydrophilic group with an average particle diameter of 20.4-234.1 nm is prepared on the surface of a nano-scale polymer microsphere.

A gas hydrate nano-accelerator with controllable particle size, under the protection of nitrogen, add deionized water, hydrophilic monomer and part of hydrophobic monomer in sequence under stirring conditions, so that the two monomers can be mixed evenly; After mixing, raise the temperature to 70-80°C and add the initiator dropwise, react at a constant temperature of 70-80°C for 0.5-1h, then add the remaining part of the hydrophobic monomer dropwise, and make the hydrophilic monomer in the hydrophilic monomer drop by seed soap-free emulsion polymerization The functional groups are covalently bonded on the surface of nanoscale polymer microspheres to prepare gas hydrate nano accelerators coated with hydrophilic groups with a particle size of 20.4-234.1nm.

The gas hydrate nano-accelerator coated with the hydrophilic group is naturally cooled to 30°C to obtain a concentrated hydrate-forming nano-accelerator, which can be used to promote hydration after being diluted to a mass fraction of 0.01%-0.5% The generation of things.

The structural formula of the described sulfonate type hydrophilic monomer is as follows:

In the formula, R is styryl, allyl, methallyl, methacryloyloxyethyl, methacryloyloxypropyl or undecyloxyethyl;

The structural formula of the quaternary ammonium root type hydrophilic monomer is as follows:

In the formula, R is methacryloyloxyethyl or methacryloyloxyethylbenzyl.

The hydrophobic comonomers are styrene and acrylic monomers;

The initiator is potassium persulfate, ammonium persulfate or azobisisobutylamidine hydrochloride.

Mix the monomers evenly, add the initiator dropwise at a rate of 1-5 drops/5s at a stirring rate of 300-500rpm, then react at a constant temperature of 70-80°C for 0.5-1h, and then add 1-3 drops Add the remaining part of the hydrophobic monomer dropwise at a dropping speed of /20s.

The preparation method firstly prepares polymer seeds, then prepares nano accelerators on the basis of seeds, and controls the monodispersity of nano accelerators by controlling the conditions of seed soap-free emulsion polymerization, for example, the reaction temperature is 70-80 ° C, When the stirring rate is 300-500rpm, the dropping rate of the initiator is 1-5 drops/5s, and the dropping rate of the hydrophobic monomer is 1-3 drops/20s, the obtained nanoaccelerator has good monodispersity and particle size distribution The index is within 5%.

The advantages of the present invention: most of the existing hydrate accelerators are complexes of surfactants and other substances, but the presence of surfactants tends to cause a large amount of foam during the hydrate decomposition process, which is not conducive to its industrial application. The accelerator of the present invention connects the hydrophilic functional monomer in the surfactant to the surface of polymer microspheres through seed soap-free emulsion polymerization, and can prepare nano-scale, good monodispersity, and adjustable particle size. The controlled gas hydrate nano accelerator has a particle diameter of 20.4-234.1nm and a monodispersity index within 5%. In addition, the nanoaccelerator of the present invention can realize the rapid generation of gas hydrate, and has excellent recycling performance.

Description of drawings

Fig. 1 is a flowchart of the preparation of nanoaccelerator provided by the embodiment of the present invention.

Fig. 2 is a schematic structural diagram of the gas hydrate nano-accelerator provided by the embodiment of the present invention and its scanning electron micrograph, wherein the schematic diagram is on the left and the scanning electron micrograph is on the right.

Fig. 3 is a transmission electron micrograph of the sulfonate-type gas hydrate nanoaccelerator provided by the embodiment of the present invention.

Fig. 4 is a transmission electron micrograph of the quaternary ammonium gas hydrate nanoaccelerator provided by the embodiment of the present invention.

Fig. 5 is a transmission electron micrograph of a sulfonate-type gas hydrate nanoaccelerator provided by an embodiment of the present invention when the ratio of hydrophilic and hydrophobic monomers is changed.

Fig. 6 is a schematic diagram of a gas hydrate generating device provided by an embodiment of the present invention.

Fig. 7 is a methane hydrate formation rate curve when using a sulfonate-type gas hydrate nano-accelerator provided by an embodiment of the present invention.

Fig. 8 is the methane hydrate generation rate curve in the 8 cycle experiments when the sulfonate-type gas hydrate nanoaccelerator is used according to the embodiment of the present invention.

specific embodiment

The features of the present invention are described below by examples, but the present invention is not limited to the following examples.

In the present invention, in a reaction vessel with a temperature control system, a stirring system and a nitrogen protection system, deionized water, hydrophilic monomers and a small amount of hydrophobic monomers are sequentially added under nitrogen protection atmosphere and high-speed stirring conditions, so that the reaction is simple The mixture is evenly mixed; the reaction system is heated up to the reaction temperature, and the initiator is slowly added dropwise. After a period of constant temperature reaction, the hydrophobic monomer is slowly added dropwise, and the hydrophilic functional groups (sulfonate, quaternary ammonium) Hydrophilic group-coated gas hydrate nanoaccelerators were prepared on the surface of nanoscale polymer microspheres by covalent bonds. After the reaction is completed and the temperature is naturally lowered, the material is discharged, and the concentrated hydrate formation nanoaccelerator is prepared; after dilution, it can be used to promote the rapid formation of gas hydrate.

The present invention connects the hydrophilic functional groups (such as sulfonate groups, quaternary ammonium groups, etc.) The gas hydrate nano-accelerator coated with water-based groups, its schematic diagram and physical map are shown in Figure 1, the accelerator can significantly shorten the induction period of hydrate formation, increase the rate of hydrate formation and gas storage capacity; in addition, with Compared with surfactants, when the accelerator is used, no foam will be generated during the hydrate decomposition process, and the accelerator has excellent recycling performance.

Example 1

Preparation of sulfonate-type nanoaccelerator (1):

The experimental operation steps for the preparation of sulfonate-type nanoaccelerators: add 80 g of deionized water and 1 g of sodium p-styrene sulfonate into a reaction vessel with a temperature control system, a stirring system, a condensation system and a nitrogen protection system, set the stirring to 300 rpm and Stir for 10 minutes to disperse the hydrophilic monomer evenly in water; then add 1 g of styrene and stir for 30 minutes to mix the reaction monomer evenly; raise the temperature of the reaction system to 70°C, add 10 mL of 20 g/L potassium persulfate solution, drop The acceleration is 1 drop/1s, and after 30 minutes of reaction, slowly add 4 g of styrene dropwise at a rate of 1 drop/20s, keep the temperature at 70°C for 5 hours, cool down to 30°C naturally, and discharge.

The obtained nanoaccelerator transmission electron microscope photo is shown in Figure 3, the nanoaccelerator is a uniform nanosphere with a uniform particle size, the average particle diameter is 46.6nm, and the monodispersity index is 1%.

Example 2

Preparation of quaternary ammonium root type nano accelerator:

The experimental operation steps for the preparation of quaternary ammonium root-type nanoaccelerators: add 80g of deionized water and 1g of methacryloyloxyethyltrimethylammonium bromide into a reaction vessel with a temperature control system, a stirring system, a condensation system and a nitrogen protection system , set the stirring to 400rpm and stir for 10min to disperse the hydrophilic monomer evenly in water; then add 1g of styrene and stir for 30min to mix the reaction monomer evenly; raise the temperature of the reaction system to 80°C and add 20g/L of Azodiisobutylamidine hydrochloride 10mL, the dropping rate is 1 drop/1s, after reacting for 30min, slowly add 4g of styrene dropwise, the dropping rate is 1 drop/20s, keep the reaction at 80°C for 4h, cool down to 30°C naturally, material.

The obtained nanoaccelerator transmission electron microscope photo is shown in Figure 4, the nanoaccelerator is a uniform nanosphere with a uniform particle size, the average particle diameter is 36.6nm, and the monodispersity index is 1.5%.

Example 3

Preparation of sulfonate-type nano accelerator (two):

The experimental operation steps for the preparation of sulfonate-type nanoaccelerators: add 80 g of deionized water and 1 g of sodium p-styrene sulfonate into a reaction vessel with a temperature control system, a stirring system, a condensation system and a nitrogen protection system, set the stirring to 300 rpm and Stir for 10 minutes to disperse the hydrophilic monomer evenly in water; then add 1 g of styrene and stir for 30 minutes to mix the reaction monomer evenly; raise the temperature of the reaction system to 70°C, add 10 mL of 20 g/L potassium persulfate solution, drop The acceleration is 1 drop/1s, and after 30 minutes of reaction, slowly add 9 g of styrene dropwise at a rate of 1 drop/20s, keep the temperature at 70°C for 5 hours, cool down to 30°C naturally, and discharge.

The obtained nanoaccelerator transmission electron microscope photo is shown in Figure 5, the nanoaccelerator is a uniform nanosphere with a uniform particle size, the average particle diameter is 234.1nm, and the monodispersity index is 3%.

Application example(1)

Using the above-mentioned embodiment 1 to obtain the sulfonate-type nano accelerator as the experimental group, using sodium lauryl sulfate as the control group for the methane hydrate generation experiment respectively, the experimental device is shown in Figure 6, mainly comprising: 1 gas source, 2-7 Stop valve, 8 Check valve, 9 Stirring device, 10-11 Temperature sensor, 12-13 Pressure sensor, 14 Piston type buffer container (1L), 15 Reactor (200mL), 16 Vacuum pump, 17 Constant temperature water bath, 18 flow pumps, 19 electronic balances, 20 computers. The experimental operation process is as follows: set the temperature of the constant temperature water bath 17 to be 275.15K and keep this temperature constant throughout the experiment; open the stop valve 2, fill the buffer container 14 with methane to 8MPa, close the stop valve 2; prepare the mass fraction Add 30mL of 0.1% sulfonate-based nanoaccelerator into the reactor 15 and seal it; when the temperature in the reactor 15 reaches 275.15K, open the stop valve 5 and the vacuum pump 16, vacuumize the reactor 15 to remove air, and close the stop valve. Valve 5 and vacuum pump 16; open shut-off valve 3, fill methane into reactor 15 from buffer container 14 to 6 MPa, close shut-off valve 3; start the hydrate formation experiment, the temperature and pressure in reactor 15 are respectively determined by temperature sensor 10 -11 and pressure sensor 12 are tested and recorded by computer 20.

The initial multiple change of hydrate during the hydrate formation process is shown in Figure 7. When sodium lauryl sulfate is used as the accelerator, the induction period of the hydrate formation process is 366 minutes, the hydrate growth process is completed in 90-100 minutes, and the final hydrate The gas storage capacity of the hydrate reaches 90 times; while the induction period of the hydrate formation process is 8.5 minutes when the sulfonate-type nanoaccelerator is used, the hydrate growth process is completed in 50-70 minutes, and the final gas storage capacity of the hydrate reaches 140 times, indicating that the present invention provides The sulfonate-type nanoaccelerator has an excellent promoting effect on the methane hydrate formation process. In addition, when sodium lauryl sulfate is used as the accelerator, a lot of foam is generated during the hydrate decomposition process, but when the sulfonate-type nano-accelerator is used, the hydrate decomposition process basically does not generate foam, which is conducive to the circulation of the nano-accelerator use. Figure 8 shows the hydrate reaction rate in 8 hydrate cycle experiments when using Example 1 to obtain the sulfonate-type nanoaccelerator. It can be seen from it that the hydrate formation process in the 8 experiments was completed within 1-2h, and the gas storage The multiples all reach 130-140 times, indicating that the sulfonate-type nano accelerator provided by the present invention has excellent recycling performance.

Those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and equivalent technologies thereof, the present invention intends to include these modifications and variations.

Claims (7)

1. A gas hydrate nano-promoter with controllable particle size, characterized in that: the nano-promoter is a nano-promoter obtained by a seed-free emulsion polymerization of a hydrophilic monomer and a hydrophobic monomer; wherein, the hydrophilic The water-based monomer is a sulfonate-type or quaternary ammonium-type comonomer, the hydrophobic monomer is styrene and acrylic monomer, and the ratio of hydrophilic and hydrophobic monomers is 1:1-1:10. 2. The gas hydrate nano accelerator with controllable particle size according to claim 1 is characterized in that: the structural formula of the sulfonate type hydrophilic monomer is as follows: In the formula, R is styryl, allyl, methallyl, methacryloyloxyethyl, methacryloyloxypropyl or undecyloxyethyl; The structural formula of the quaternary ammonium root type hydrophilic monomer is as follows: In the formula, R is methacryloyloxyethyl or methacryloyloxyethylbenzyl. The hydrophobic comonomers are styrene or acrylate monomers. 3. The gas hydrate nano accelerator with controllable particle size according to claim 1 or 2 is characterized in that: under nitrogen protection, under stirring conditions, add deionized water, hydrophilic monomer and part of hydrophobic Monomer, mix the two reactive monomers evenly; after mixing, heat up to 70-80°C, then add the initiator dropwise, react at a constant temperature of 70-80°C for 0.5-1h, then add the remaining hydrophobic monomer dropwise, pass Seed soap-free emulsion polymerization The hydrophilic functional group in the hydrophilic monomer is covalently bonded to the surface of the nano-scale polymer microsphere to prepare a hydrophilic group-coated product with an average particle size of 20.4-234.1nm Gas hydrate nano accelerator. 4. A gas hydrate nano-promoter with controllable particle size according to claim 1, characterized in that: under nitrogen protection, deionized water, hydrophilic monomers and partial hydrophobic monomers are added successively under stirring conditions Monomer, mix the two monomers evenly; after mixing, raise the temperature to 70-80°C and add the initiator dropwise, react at a constant temperature of 70-80°C for 0.5-1h, then add the remaining hydrophobic monomer dropwise, through the seedless Soap emulsion polymerization connects the hydrophilic functional group in the hydrophilic monomer to the surface of the nano-scale polymer microsphere by covalent bond to prepare the gas hydrate nanometer coated with the hydrophilic group with a particle size of 20.4-234.1nm. Accelerator. 5. The gas hydrate nano accelerator with controllable particle size according to claim 4, characterized in that: the gas hydrate nano accelerator coated with hydrophilic groups is naturally cooled to 30°C to obtain concentrated The hydrate formation nanoaccelerator can be used to promote the formation of hydrate after being diluted to a mass fraction of 0.01%-0.5%. 6. The gas hydrate nano accelerator with controllable particle size according to claim 4, characterized in that: the structural formula of the sulfonate type hydrophilic monomer is as follows: In the formula, R is styryl, allyl, methallyl, methacryloyloxyethyl, methacryloyloxypropyl or undecyloxyethyl; The structural formula of the quaternary ammonium root type hydrophilic monomer is as follows: In the formula, R is methacryloyloxyethyl or methacryloyloxyethylbenzyl. The hydrophobic comonomers are styrene and acrylic monomers; The initiator is potassium persulfate, ammonium persulfate or azobisisobutylamidine hydrochloride. 7. The gas hydrate nano-promoter with controllable particle size according to claim 4, characterized in that: the monomers are mixed evenly, and at a stirring rate of 300-500rpm, 1-5 drops/5s Add the initiator dropwise at an acceleration rate, then react at a constant temperature of 70-80°C for 0.5-1h, and then add the remaining hydrophobic monomer dropwise at a dropping rate of 1-3 drops/20s.