Nanoparticles, preparation method thereof and application in foam stabilization
By preparing CNC@NIPAM nanoparticles as foam stabilizers, the problem of sudden drop in foam stability at high temperatures in foam drainage and gas production technology was solved, a temperature-responsive foam stabilization effect was achieved, and the scope of application was expanded.
Patent Information
- Application Number
- CN202210018058.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-01-07
- Publication Date
- 2025-09-23
- Estimated Expiration
- 2042-01-07
AI Technical Summary
The existing foam drainage and gas production technology has a sudden drop in foam stability at high temperatures, leading to blockage and increased costs, and cannot be effectively used at low temperatures, limiting its scope of application.
CNC@NIPAM nanoparticles are used as foam stabilizers, and their foam stabilization function is adjusted by controlling the temperature. The preparation method includes dissolution, deoxygenation, stirring, reaction and centrifugation to obtain nanoparticles with a median particle size of 20 to 200 nm.
The invention realizes the effect of stable foam at high temperature and temperature responsiveness of unstable foam at low temperature, solves the problems of stable foam at high temperature and unstable foam at low temperature that cannot be achieved in the prior art, simplifies the process flow and reduces costs.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to the field of modified nanoparticles, and in particular to CNC@NIPAM nanoparticles, a preparation method thereof, and application in foam stabilization. Background Art
[0002] In the later stages of natural gas production, low well pressure and reduced drainage capacity lead to large amounts of accumulated liquid, resulting in reduced production efficiency. Foam dewatering is widely used in natural gas production due to its simple operation and excellent drainage performance. This process involves adding a foaming agent, primarily a surfactant, to the bottomhole. This agitation of the natural gas causes the accumulated liquid to mix thoroughly with the foaming agent, forming a large amount of foam. This reduces friction losses and gravity gradients within the flowing well tubing, effectively lowering bottomhole backpressure and enabling continuous liquid lift. Foam has a strong regeneration capacity. When its aqueous solution is carried by the airflow to surface pipelines and separation equipment, it is repeatedly agitated, causing some foam to accumulate in the separator. This phenomenon is particularly severe when excessive amounts of foaming agent are used or the foam is overly stable. Large amounts of foam can be carried into the gathering pipeline, causing blockages and increasing gathering pressure. Therefore, a defoaming agent is injected at the separator inlet to enter the separator along with the gas-water mixture, thereby defoaming and inhibiting foam regeneration, facilitating gas-water separation. The addition of defoamers limits the recycling of foaming agents, while the introduction of defoaming equipment increases the process steps, both of which increase development costs. In some desert and cold regions, the supporting facilities for the foaming process are severely lacking, limiting its application.
[0003] Foam drainage and gas production technology has entered the stage of personalized application, giving the foam intelligent responsiveness, so that it foams at the wellbore temperature and defoams at the ground temperature, thereby eliminating the defoaming link in the conventional foam drainage process and simplifying the foam drainage process. It has important research value for reducing the cost of foam drainage and gas production and expanding the application scope of foam drainage and gas production.
[0004] Thermosensitive foam refers to foam whose stability can be regulated by temperature. In 2011, the French Fameau team took the lead in conducting research on thermosensitive foams. By using 12-hydroxystearic acid (12-HSA) and ethanolamine salt or hexanolamine salt to co-assemble, they reported for the first time an ultra-stable temperature-responsive foam, which can achieve reversible transformation of foam in the temperature range of 20 to 50 ° C. However, at high temperatures, the water phase in the foam begins to evaporate faster or even boil, resulting in a sharp drop in foam stability. Therefore, it is necessary to develop a foam stabilizer that has the function of stabilizing foam at high temperatures but not at low temperatures. Summary of the Invention
[0005] One aspect of the present invention provides a nanoparticle, which is a CNC@NIPAM nanoparticle, wherein the median particle size of the nanoparticle is 20 to 200 nm.
[0006] In one embodiment, the mass ratio of the CNC to the NIPAM is 1:1 to 1:3.
[0007] The second aspect of the present invention provides a method for preparing the nanoparticles according to the first aspect of the present invention, comprising the following steps:
[0008] 1) dissolving CNC in water and removing oxygen to obtain a degassed CNC aqueous solution;
[0009] 2) dissolving NIPAM in water and removing oxygen to obtain a degassed NIPAM aqueous solution;
[0010] 3) adding an initiator to the degassed CNC aqueous solution and stirring at a first temperature to obtain a stirred solution;
[0011] 4) cooling the stirred liquid to a second temperature, adding the degassed NIPAM aqueous solution to the stirred liquid at the second temperature, and stirring and reacting at a third temperature to obtain a modified reaction liquid;
[0012] 5) Centrifuging the second reaction solution, removing the supernatant to obtain a precipitate, washing and dialyzing the precipitate to obtain the nanoparticles.
[0013] In one embodiment, in step 1), the concentration of the CNC in the degassed CNC aqueous solution is 0.5 wt % to 2.5 wt %.
[0014] In one embodiment, in step 2), the concentration of NIPAM in the degassed NIPAM aqueous solution is 0.5 wt % to 2.5 wt %.
[0015] In one embodiment, in step 3), the final concentration of the added initiator is 0.1 wt % to 0.5 wt %.
[0016] In one embodiment, the initiator is ammonium persulfate and / or sodium bisulfite.
[0017] In one embodiment, in step 4), the mass ratio of the CNC to the NIPAM is 1:1 to 1:3.
[0018] In one embodiment, the first temperature is 50 to 70°C.
[0019] In one embodiment, the second temperature is 40 to 60°C.
[0020] In one embodiment, the third temperature is 70 to 90°C.
[0021] In one embodiment, stirring is performed at the first temperature for 5 to 25 minutes; and reaction is performed at the third temperature for 2 to 6 hours.
[0022] The third aspect of the present invention provides the use of the nanoparticles described in one of the present inventions or the nanoparticles prepared by the method described in any one of the second aspect of the present invention in foam stabilization.
[0023] Beneficial effects of the present invention:
[0024] The CNC@NIPAM nanoparticles of the present invention have good foam stabilization function, and the foam stabilization function is temperature-responsive, that is, they do not have the foam stabilization function at low temperatures; but can play a role in stabilizing foam at high temperatures above 60°C or even above 80°C. DETAILED DESCRIPTION
[0025] The present invention will be further described below with reference to examples. However, the examples are merely illustrative and do not limit the present invention in any way.
[0026] Example 1
[0027] Degassing of the reactants: A 0.5 wt% aqueous solution of cellulose nanocrystals (CNC) with a median particle size of 20 nm and a 0.5 wt% aqueous solution of N-isopropylacrylamide (NIPAM) were purged with nitrogen for 0.5 h under continuous stirring to remove oxygen, thereby obtaining a degassed CNC aqueous solution and a degassed NIPAM aqueous solution, respectively.
[0028] Modification reaction: Add the initiator ammonium persulfate to the degassed CNC aqueous solution with a final concentration of 0.1 wt%, keep stirring at 50 ° C for 5 minutes, then cool to 40 ° C, and then add the degassed NIPAM aqueous solution (V aq(CNC) :V aq(NIPAM) =1:1), and slowly raise the temperature to 70°C, and keep stirring at 70°C for 6 hours to obtain a modified reaction solution.
[0029] Reactant Treatment: The resulting modified reaction solution was centrifuged at 12,000 rpm for 40 minutes, the supernatant removed, and washed with deionized water. The solution was then centrifuged at 12,000 rpm for 40 minutes, the supernatant removed, and washed with deionized water and centrifuged three times in the same manner. The washed precipitate was frozen overnight and lyophilized to obtain NIPAM-grafted modified CNC nanoparticles, denoted as CNC@NIPAM. The CNC:NIPAM mass ratio in these NIPAM-grafted modified CNC nanoparticles was 1:1, and the median particle size was 20 nm.
[0030] Example 2
[0031] Degassing of the reactants: A 1.0 wt% CNC aqueous solution with a median particle size of 60 nm and a 1.0 wt% NIPAM aqueous solution were purged with nitrogen for 1 h under continuous stirring to remove oxygen, thereby obtaining a degassed CNC aqueous solution and a degassed NIPAM aqueous solution, respectively.
[0032] Modification reaction: Add the initiator ammonium persulfate to the degassed CNC aqueous solution with a final concentration of 0.2 wt%, keep stirring at 55 ° C for 10 min, then cool to 45 ° C, and then add the degassed NIPAM aqueous solution (V aq(CNC) :V aq(NIPAM) =1:1.5), and slowly raise the temperature to 75°C, and keep stirring at 75°C for 5 hours to obtain a modified reaction solution.
[0033] Reactant Processing: The modified reaction solution was centrifuged at 11,000 rpm for 50 minutes, the supernatant removed, and the mixture washed with deionized water and centrifuged three times in the same manner. The washed precipitate was frozen overnight and lyophilized to obtain the desired NIPAM-grafted CNC nanoparticles, denoted as CNC@NIPAM. The mass ratio of CNC to NIPAM in these NIPAM-grafted CNC nanoparticles was 1:1.5, and the median particle size was 60 nm.
[0034] Example 3
[0035] Degassing of the reactants: A 1.5 wt % CNC aqueous solution with a median particle size of 110 nm and a 1.5 wt % NIPAM aqueous solution were purged with nitrogen for 1.5 h under continuous stirring to remove oxygen, thereby obtaining a degassed CNC aqueous solution and a degassed NIPAM aqueous solution, respectively.
[0036] Modification reaction: Add the initiator ammonium persulfate to the degassed CNC aqueous solution with a final concentration of 0.3 wt%, keep stirring at 60 ° C for 15 min, then cool to 50 ° C, and then add the degassed NIPAM solution (V aq(CNC) :V aq(NIPAM) =1:2), and slowly heated to 80°C, and stirred at 80°C for 4 h to obtain a modified reaction solution.
[0037] Reactant Treatment: The resulting modified reaction solution was centrifuged at 10,000 rpm for 50 minutes, the supernatant removed, and the mixture was washed and centrifuged three times with deionized water in the same manner. The washed precipitate was frozen overnight and lyophilized to obtain the desired NIPAM-grafted modified CNC nanoparticles, denoted as CNC@NIPAM. The mass ratio of CNC to NIPAM in these NIPAM-grafted modified CNC nanoparticles was 1:2, and the median particle size was 110 nm.
[0038] Example 4
[0039] Degassing of the reactants: A 2 wt % CNC aqueous solution with a median particle size of 150 nm and a 2 wt % NIPAM aqueous solution were purged with nitrogen for 2 h under continuous stirring to remove oxygen, thereby obtaining a degassed CNC aqueous solution and a degassed NIPAM aqueous solution, respectively.
[0040] Modification reaction: Add the initiator ammonium persulfate to the degassed CNC aqueous solution with a final concentration of 0.4 wt%, keep stirring at 65 ° C for 20 min, then cool to 55 ° C, and then add the degassed NIPAM aqueous solution (V aq(CNC) :V aq(NIPAM) =1:2.5), and slowly raise the temperature to 85°C, and keep stirring at 85°C for 3 hours to obtain a modified reaction solution.
[0041] Reactant Treatment: The resulting modified reaction solution was centrifuged at 9000 rpm for 60 minutes, the supernatant removed, and the mixture washed with deionized water and centrifuged three times in the same manner. The washed precipitate was frozen overnight and lyophilized to obtain the desired NIPAM-grafted modified CNC nanoparticles, denoted as CNC@NIPAM. The mass ratio of CNC to NIPAM in these NIPAM-grafted modified CNC nanoparticles was 1:2.5, and the median particle size was 150 nm.
[0042] Example 5
[0043] Degassing of the reactants: A 2.5 wt% CNC aqueous solution with a median particle size of 200 nm and a 2.5 wt% NIPAM aqueous solution were purged with nitrogen for 2.5 h under continuous stirring to remove oxygen, thereby obtaining a degassed CNC aqueous solution and a degassed NIPAM aqueous solution, respectively.
[0044] Modification reaction: Add the initiator ammonium persulfate to the degassed CNC aqueous solution with a final concentration of 0.5 wt%, keep stirring at 70 ° C for 25 min, then cool to 60 ° C, and then add the degassed NIPAM aqueous solution (V aq(CNC) :V aq(NIPAM)=1:3), and slowly raise the temperature to 90°C, and keep stirring at 90°C for 2 hours to obtain a modified reaction solution.
[0045] Reactant Treatment: The resulting modified reaction solution was centrifuged at 9000 rpm for 50 minutes, the supernatant removed, and the mixture washed with deionized water and centrifuged three times in the same manner. The washed precipitate was lyophilized overnight to obtain the desired NIPAM-grafted modified CNC nanoparticles, denoted as CNC@NIPAM. The CNC:NIPAM mass ratio in the NIPAM-grafted modified CNC nanoparticles was 1:1, and the median particle size was 200 nm.
[0046] Example 6
[0047] Sodium lauryl sulfate and lauryl betaine are added to deionized water so that the content of sodium lauryl sulfate is 2 wt % and the content of lauryl betaine is 15 wt %, and the mixture is mixed uniformly to obtain a foaming agent.
[0048] The CNC@NIPAM nanoparticles prepared in Example 1, a foaming agent, and water with a salinity of 200,000 ppm were uniformly mixed to obtain a test solution, wherein the content of the CNC@NIPAM nanoparticles in the test solution was 0.2 wt %, and the content of the foaming agent in the test solution was 0.3 wt %.
[0049] Example 7
[0050] The preparation of the foaming agent is the same as in Example 6.
[0051] The CNC@NIPAM nanoparticles prepared in Example 2, a foaming agent, and water with a salinity of 200,000 ppm were uniformly mixed to obtain a test solution, wherein the content of the CNC@NIPAM nanoparticles in the test solution was 0.2 wt %, and the content of the foaming agent in the test solution was 0.3 wt %.
[0052] Example 8
[0053] The preparation of the foaming agent is the same as in Example 6.
[0054] The CNC@NIPAM nanoparticles prepared in Example 3, a foaming agent, and water with a salinity of 200,000 ppm were uniformly mixed to obtain a test solution, wherein the content of the CNC@NIPAM nanoparticles in the test solution was 0.2 wt %, and the content of the foaming agent in the test solution was 0.3 wt %.
[0055] Example 9
[0056] The preparation of the foaming agent is the same as in Example 6.
[0057] The CNC@NIPAM nanoparticles prepared in Example 4, a foaming agent, and water with a salinity of 200,000 ppm were uniformly mixed to obtain a test solution, wherein the content of the CNC@NIPAM nanoparticles in the test solution was 0.2 wt %, and the content of the foaming agent in the test solution was 0.3 wt %.
[0058] Example 10
[0059] The preparation of the foaming agent is the same as in Example 6.
[0060] The CNC@NIPAM nanoparticles prepared in Example 5, a foaming agent, and water with a salinity of 200,000 ppm were uniformly mixed to obtain a test solution, wherein the content of the CNC@NIPAM nanoparticles in the test solution was 0.2 wt %, and the content of the foaming agent in the test solution was 0.3 wt %.
[0061] Comparative Example 1
[0062] The preparation of the foaming agent is the same as in Example 6.
[0063] CNC nanoparticles with a median particle size of 20 nm, a foaming agent and water with a salinity of 200,000 ppm were uniformly mixed to obtain a test solution, wherein the content of the CNC nanoparticles in the test solution was 0.2 wt %, and the content of the foaming agent in the test solution was 0.3 wt %.
[0064] Comparative Example 2
[0065] The preparation of the foaming agent is the same as in Example 6.
[0066] CNC nanoparticles with a median particle size of 200 nm, a foaming agent and water with a salinity of 200,000 ppm are uniformly mixed to obtain a test solution, wherein the content of the CNC nanoparticles in the test solution is 0.2 wt %, and the content of the foaming agent in the test solution is 0.3 wt %.
[0067] Comparative Example 3
[0068] The preparation of the foaming agent is the same as in Example 6.
[0069] PNIPAM preparation process:
[0070] Degassing of the reactants: A 0.5 wt % N-isopropylacrylamide (NIPAM) aqueous solution was purged with nitrogen for 0.5 h under continuous stirring to remove oxygen, thereby obtaining a degassed NIPAM aqueous solution.
[0071] Polymerization reaction: add ammonium persulfate as an initiator to a final concentration of 0.1 wt % to the degassed NIPAM aqueous solution, slowly heat the solution to 70° C., and stir the solution at 70° C. for 6 h to obtain a polymerization reaction solution.
[0072] Reactant treatment: The obtained reaction solution was dialyzed for 14 days using a dialysis bag with a cutoff phase number average molecular weight of 12,000 to obtain a dialyzed sample, which was frozen overnight and then lyophilized.
[0073] PNIPAM, a foaming agent and water with a salinity of 200,000 ppm are uniformly mixed to obtain a test solution, wherein the content of PNIPAM in the test solution is 0.2 wt % and the content of the foaming agent in the test solution is 0.3 wt %.
[0074] Comparative Example 4
[0075] The preparation of the foaming agent is the same as in Example 6.
[0076] The foaming agent is mixed evenly with water having a salinity of 200,000 ppm to obtain a test solution, and the content of the foaming agent in the test solution is 0.3 wt %.
[0077] Performance measurement
[0078] The foam performance (foaming power and foam stabilization power) of the test solution was evaluated using a Roche foam instrument as follows:
[0079] Set the temperature to the test temperature. Allow 200 mL of the test solution or blank to flow freely down the tube. This will impact 50 mL of the same sample solution in the tube, generating foam. Record the foam height immediately after the 200 mL test solution is drained and the foam height 5 minutes later to evaluate the foaming and stabilizing abilities of the foaming agent, respectively. Repeat each test three times and take the average value. The results are shown in Table 1.
[0080] Table 1
[0081]
[0082]
[0083]
[0084] From the experimental data in Table 1, it can be seen that the initial bubble height H0 and the foam height H5 after 5 minutes generated by the test solutions of Comparative Examples 1 and 2 show a trend of gradually decreasing with increasing temperature, and the initial bubble height H0 and the foam height H5 after 5 minutes at low temperatures are significantly higher than those of Comparative Example 4, indicating that the stability of the foam generated by the test solutions of Comparative Examples 1 and 2 decreases with increasing temperature, and the CNC nanoparticles have very poor foam stabilization effect at high temperatures and are not temperature-sensitive. Comparing the foams generated by the test solutions of Comparative Examples 3 and 4 at different temperatures, it can be seen that at low temperatures below 40°C, the initial bubble height H0 and the foam height H5 after 5 minutes in Comparative Example 3 are both higher than those in Comparative Example 4, indicating that PNIPAM has a certain foam stabilization function at low temperatures. However, when the temperature is increased to ≥40°C, the initial bubble height H0 and the foam height H5 after 5 minutes in Comparative Example 3 are the same as those in Comparative Example 4, indicating that PNIPAM has no foam stabilization function at high temperatures and therefore cannot achieve a foam stabilization effect. The foams produced by the test solutions prepared in Examples 6 to 10 showed a trend of gradually increasing initial bubble height H0 and foam height H5 after 5 minutes as the temperature increased. As the temperature decreased again, the initial bubble height H0 and foam height H5 after 5 minutes gradually decreased again. This indicates that the CNC@NIPAM nanoparticles prepared in the present invention have good foam stability and temperature-sensitive responsiveness, that is, they do not have a foam stabilizing function at low temperatures, but can play a role in stabilizing foam at high temperatures above 60°C, or even above 80°C.
[0085] Although the present invention has been described with reference to specific embodiments, those skilled in the art will appreciate that various modifications may be made without departing from the true spirit and scope of the invention. Furthermore, the subject matter, spirit, and scope of the invention may be modified in various ways to adapt to specific circumstances, materials, combinations of materials, and methods. All such modifications are intended to be within the scope of the claims.
Claims
1. Application of nanoparticles in foam stabilization, wherein the nanoparticles are CNC@NIPAM nanoparticles, and the median particle size of the nanoparticles is 20 to 200 nm.
2. The use according to claim 1, characterized in that The mass ratio of the CNC to the NIPAM is 1:1 to 1:
3.
3. The use according to claim 1 or 2, characterized in that The nanoparticles are prepared according to the following steps: 1) Dissolve CNC in water and remove oxygen to obtain a degassed CNC aqueous solution; 2) Dissolving NIPAM in water and removing oxygen to obtain a degassed NIPAM aqueous solution; 3) adding an initiator to the degassed CNC aqueous solution and stirring at a first temperature to obtain a stirred solution; 4) cooling the stirred liquid to a second temperature, adding the degassed NIPAM aqueous solution to the stirred liquid at the second temperature, and stirring and reacting at a third temperature to obtain a modified reaction liquid; 5) Centrifuging the modified reaction solution, removing the supernatant to obtain a precipitate, washing and dialyzing the precipitate to obtain the nanoparticles.
4. The use according to claim 3, characterized in that In step 1), the concentration of the CNC in the degassed CNC aqueous solution is 0.5 wt % to 2.5 wt %; and / or In step 2), the concentration of NIPAM in the degassed NIPAM aqueous solution is 0.5 wt % to 2.5 wt %.
5. The use according to claim 3, characterized in that In step 3), the final concentration of the added initiator is 0.1 wt % to 0.5 wt %.
6. The use according to claim 3, characterized in that The initiator is ammonium persulfate and / or sodium bisulfite.
7. The use according to claim 3, characterized in that The first temperature is 50 to 70°C, and / or The second temperature is 40 to 60°C; and / or The third temperature is 70 to 90°C.
8. The use according to claim 3, characterized in that Stir at the first temperature for 5 to 25 minutes; and react at the third temperature for 2 to 6 hours.