Kelp mucus drag reducer and preparation method thereof

Abstract

The invention discloses a kelp mucus drag reducer and a preparation method thereof, and belongs to the field of underwater drag reduction. The kelp mucus drag reducer comprises kelp mucus and sodium bicarbonate. The preparation method comprises the following steps: pretreating kelp serving as a raw material to obtain kelp mucus; adding sodium bicarbonate powder into the pretreated kelp mucus, adjusting the pH to make a weakly alkaline environment, and filtering by adopting a filter screen to obtain kelp mucus mother liquor; calculating the concentration of the kelp mucus mother liquor; according to the measured concentration of the kelp mucus mother liquor, the kelp mucus mother liquor is dried and concentrated or diluted with water, and the kelp mucus drag reducers with different concentrations are prepared through sufficient stirring. The problems that an existing drag reducer preparation method is tedious and unfriendly to the environment are solved.

Description

Technical Field

[0001] The invention belongs to the field of underwater drag reduction, and specifically relates to a kelp mucus drag reducer and a preparation method thereof. Background Art

[0002] The drag reduction technology of adding drag reducers is an important technology for underwater vehicles to reduce resistance, save energy, increase range and speed. It is also an important application in the field of pipeline transportation to reduce drag, save energy and improve transportation efficiency. However, most of the drag reducers currently used are prepared by artificial chemical synthesis, which has a complex preparation method and high cost. In addition, due to its partial toxicity and resistance to degradation, it will also cause pollution to the environment. Therefore, the preparation of green, environmentally friendly, efficient and low-cost drag reducers is of great significance for underwater vehicle drag reduction and pipeline energy-saving transportation.

[0003] Considering the high cost and environmental pollution of chemical drag reducers, scholars have conducted many studies on green and environmentally friendly drag reducers. For example, the disclosed biological drag reducer is prepared by adding dodecanoic acid and propylene glycol to a stirred reactor and reacting them under the catalysis of immobilized lipase to form a biological drag reducer. The biological drag reducer solves the problems of lack of ecological sustainability and high energy consumption in the preparation of existing chemical drag reducers. However, the biological drag reducer is suitable for promoting turbulence formation under low-velocity laminar flow and reducing the pressure required to form turbulence, but is not suitable for high-velocity turbulent drag reduction. The disclosed biological polysaccharide drag reducer, the method obtains a composite polysaccharide by mixing microbial polysaccharides, guar gum and konjac gum in a certain proportion, and its drag reduction performance is far better than the effect obtained when various types of polysaccharides are used alone as drag reducers. The composite polysaccharide drag reducer has the characteristics of long-lasting drag reduction effect and high temperature resistance, but not all proportions of composite polysaccharides have significant drag reduction effects, and there are certain requirements for the proportions of various polysaccharides in the drag reducer. The disclosed friendly drag reducer is prepared by adding natural modified derivatives such as propylene pine acrylamide and propylene pine acryl polyethylene glycol, which improves the drag reduction rate of the drag reducer and has good thermal stability. However, the preparation method of the raw materials propylene pine acrylamide and propylene pine acryl polyethylene glycol is complicated, and the temperature control requirements are high and the preparation conditions are complicated. In terms of biological drag reducers, the drag reducer raw material is obtained by drying and crushing seeded okra into powder. The drag reducer obtained after mixing with water has the advantages of simple preparation and environmental friendliness. However, crushing okra will destroy the structure of the high-molecular drag reduction effective substance therein, resulting in a decrease in the drag reduction performance of the obtained drag reducer. There is also a biological drag reducer prepared by mixing aloe inner leaf mucus and aloe fiber, which has significant advantages in low cost, non-toxicity and environmental protection. However, the organic acid in aloe vera will damage the aloe polysaccharide and reduce the polysaccharide content, resulting in a weakened drag reduction effect.

[0004] In summary, the existing biological drag reducers are prepared by chemical methods or obtained by biological material processing. The biological drag reducers prepared by chemical methods have problems such as cumbersome preparation methods and limited applicable conditions, while the biological drag reducers obtained by biological material processing have problems such as easy degradation and failure. Based on the above problems, the preparation of efficient, easy-to-use, and non-failure biological drag reducers is the focus of today's biological drag reducer preparation. Summary of the invention

[0005] Technical issues to be solved:

[0006] In order to avoid the shortcomings of the prior art, the present invention provides a kelp mucus drag reducer and a preparation method thereof, using natural marine algae kelp as raw material, extracting and measuring kelp drag reducing material laminarin by water extraction, alkali extraction and alcohol precipitation to prepare kelp mucus drag reducers of different concentrations, the preparation process is not only simple and convenient, but also environmentally friendly and ecologically sustainable. The present invention solves the problem that the existing drag reducer preparation method is cumbersome and unfriendly to the environment.

[0007] The technical scheme of the present invention is: a kelp mucus drag reducer, comprising kelp mucus and sodium bicarbonate, with the mass ratio of kelp mucus:sodium bicarbonate=100:8-15.

[0008] A further technical solution of the present invention is: the method for obtaining the kelp mucus is to take unwashed kelp as raw material, cut the kelp into thin slices, obtain kelp fragments and part of the kelp mucus, dilute with water, and let stand to extract the kelp mucus.

[0009] A further technical solution of the present invention is that the size of the kelp slices is no more than 2cm×2cm×0.5cm.

[0010] A method for preparing a kelp mucus drag reducer, the specific steps are as follows:

[0011] Pre-treating kelp as a raw material to obtain kelp mucus;

[0012] The pretreated kelp mucus is added with sodium bicarbonate powder, the pH value is adjusted to create a weakly alkaline environment, and the kelp mucus mother liquor is obtained by filtering with a filter;

[0013] Calculate the concentration of kelp mucus mother solution;

[0014] According to the measured concentration of the kelp mucus mother liquor, the kelp mucus mother liquor is dried and concentrated or diluted with water, and is fully stirred to prepare kelp mucus drag reducers of different concentrations.

[0015] A further technical solution of the present invention is: the pretreatment method of the kelp is to take the unwashed kelp as raw material, cut the kelp into thin slices, obtain kelp fragments and part of kelp mucus, dilute with water, and let stand to extract the kelp mucus.

[0016] A further technical solution of the present invention is: the size of the kelp slices is no more than 2cm×2cm×0.5cm, and the obtained kelp fragments and part of the kelp mucus are diluted with water 10 times the mass of the kelp and then left to stand for 24 hours to extract the kelp mucus.

[0017] A further technical solution of the present invention is that the sodium bicarbonate powder accounts for 8% to 15% of the mass of the kelp, and the solution becomes weakly alkaline without losing the viscosity of the solution, destroying the cell wall and converting alginic acid into seaweed polysaccharide to extract more kelp polysaccharide mucus by standing.

[0018] A further technical solution of the present invention is: the method for calculating the concentration of the kelp mucus mother solution is:

[0019] Taking part of the kelp mucus mother liquor for alcohol precipitation, adding ethanol to part of the kelp mucus mother liquor, precipitating kelp polysaccharide according to the alcohol insolubility of kelp polysaccharide, and subjecting the solution to centrifugal filtration to obtain kelp polysaccharide mucus precipitate;

[0020] The kelp polysaccharide mucus precipitate was centrifuged and dried, and the dry weight was measured to calculate the concentration of the kelp mucus mother liquor.

[0021] A further technical solution of the present invention is: the alcohol precipitation method is to add anhydrous ethanol to the solution until the ethanol content is 70% to 80%, and the mother liquor after adding alcohol is centrifuged at a speed of 2000r / min-4000r / min.

[0022] An application of a kelp mucus drag reducer, wherein the kelp mucus drag reducer is released on the outer surface of a vehicle, the kelp mucus drag reducer is diluted under the action of a water flow, and the viscosity of water in the surface flow field increases over time, thereby completing the drag reduction function.

[0023] Beneficial Effects

[0024] The beneficial effects of the present invention are as follows: the present invention proposes for the first time to use kelp in the field of underwater drag reduction, and prepares kelp mucus drag reducer by extracting kelp polysaccharide from kelp, thereby realizing underwater drag reduction of the drag reducer under the action of turbulence at different Re numbers. Under high Re number, the drag reduction rate of the kelp mucus drag reducer can reach 41.52%.

[0025] The kelp mucus drag reducer of the present invention has simple raw material acquisition and low cost, and only requires kelp as a raw material to prepare the kelp mucus drag reducer. While having the advantage of high economic benefits, the environmental friendliness and ecological sustainability of the prepared drag reducer are ensured.

[0026] The present invention prepares the kelp mucus drag reducer by simple operations such as water extraction, alkali extraction and alcohol precipitation. The principle is that water extraction is used to extract kelp polysaccharides for the first time, and then sodium bicarbonate is added to change the pH acidity and alkalinity to destroy the kelp cell wall and convert alginate into seaweed polysaccharides to dissolve kelp polysaccharides to extract more kelp drag reducing substances. Finally, according to the difference in solubility of kelp polysaccharides in water and ethanol, ethanol is added to extract kelp polysaccharides to determine the concentration of the kelp mucus drag reducer. There is no chemical synthesis pathway in the preparation process, the preparation operation is simple, and no toxic or environmentally polluting byproducts are produced, which is suitable for green and environmentally friendly industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is the comparative experimental result of the drag reduction rate of Example 1 of the present invention and Comparative Examples 1 and 2 at different Re.

[0028] Figure 2 The drag reduction rate over time of a drag reducer prepared by adding water to dried kelp slices for 4 hours and a drag reducer prepared by adding water to dried kelp slices for 4 hours and then adding alkali for 4 hours at Re=90675 is compared with the results. DETAILED DESCRIPTION

[0029] The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0030] Based on the fact that the existing biological drag reducers are prepared by chemical methods or obtained by processing biological materials, the biological drag reducers prepared by chemical methods have the problems of cumbersome preparation methods and limited applicable conditions, while the biological drag reducers obtained by processing biological materials have the problems of easy degradation and failure. The present invention provides a kelp mucus drag reducer, comprising kelp mucus and sodium bicarbonate, with a mass ratio of kelp mucus: sodium bicarbonate = 100:8-15.

[0031] The present invention provides a method for preparing a kelp mucus drag reducer, and the specific steps are as follows:

[0032] Step 1: Take the unwashed kelp as raw material, use scissors to cut the kelp into thin slices to avoid crushing and applying high shear force to destroy the drag reducing material, and dilute the kelp fragments and some kelp mucus with water, and let it stand to extract more kelp mucus;

[0033] Step 2: adding sodium bicarbonate powder to the mixture solution after standing, adjusting the pH to create a weakly alkaline environment, and filtering the extracted mixture solution with a filter to obtain a kelp mucus mother solution;

[0034] Step 3: taking part of the kelp mucus mother liquor for alcohol precipitation, adding ethanol to part of the kelp mucus mother liquor, precipitating kelp polysaccharide according to the alcohol insolubility of kelp polysaccharide, and centrifuging and filtering the solution to obtain kelp polysaccharide mucus precipitate;

[0035] Step 4: centrifuge and dry the laminarin mucus precipitate, measure the dry weight and calculate the concentration of the laminarin mucus mother solution;

[0036] Step 5: Dry and concentrate the kelp mucus mother liquor or dilute it with water according to the concentration of the kelp mucus mother liquor measured in step 4, and fully stir it to prepare kelp mucus drag reducers of different concentrations.

[0037] The above technical solution is further described below with reference to examples and drawings:

[0038] Experimental Example 1:

[0039] In this example, dry kelp is used as raw material, and after initial slicing treatment, kelp mucus is extracted by alkali extraction to prepare kelp mucus drag reducer.

[0040] The specific implementation steps are as follows:

[0041] Step 1: Take 100g of dried kelp and cut it into squares less than 2cm to obtain dried kelp fragments. Add water to dilute the solution to 1L and let it stand for 24h to extract more kelp mucus.

[0042] Step 2: Add 10 g of sodium bicarbonate powder to the mixture of dry kelp fragments and kelp mucus, and let it stand for extraction for 4 hours. Filter the mixture through a filter to obtain the kelp mucus mother liquor.

[0043] Step 3: Take a beaker and weigh its mass m1, take 50 ml of kelp mucus mother solution and add it to the beaker, weigh its mass m2, add 95% ethanol until the ethanol content in the solution is 75%, place the mixed solution in a centrifuge and centrifuge at a speed of 3000r / min for 5 minutes.

[0044] Step 4: Take the precipitate after centrifugation and put it into a vacuum drying oven, dry it at 20°C for 30 minutes to remove moisture, and obtain kelp mucus drag reducer powder. Weigh its mass as m3, and calculate the concentration of kelp mucus mother liquor as m3 / (m2-m1)×100%.

[0045] Step 5: Take the remaining 950 ml of kelp mucus mother liquor, add water to 5 L of total solution, stir thoroughly for 10 min, and obtain 5 L of kelp mucus drag reducer with a concentration of 0.19×m3 / (m2-m1)×100%.

[0046] Comparative Example 1:

[0047] In this case, dried kelp is used as raw material, and the kelp mucus is extracted without alkali after initial treatment to prepare the kelp mucus drag reducer.

[0048] The specific implementation steps are as follows:

[0049] Step 1: Take 100g of dried kelp, take 20g of cut dried kelp each time, add 20ml of water and put it into a juicer to crush it to get a mixture of dry kelp fragments and kelp mucus, add water to dilute the solution to 1L, and let it stand for 24 hours to extract more kelp mucus.

[0050] Step 2: Place the mixture of dry kelp fragments and kelp mucus in a filter to filter and obtain kelp mucus mother liquor.

[0051] Step 3: Take a beaker and weigh its mass m1, take 50 ml of kelp mucus mother solution and add it to the beaker, weigh its mass m2, add 95% ethanol until the ethanol content in the solution is 75%, place the mixed solution in a centrifuge and centrifuge at a speed of 3000r / min for 5 minutes.

[0052] Step 4: Take the precipitate after centrifugation and put it into a vacuum drying oven, dry it at 20°C for 30 minutes to remove moisture, and obtain kelp mucus drag reducer powder. Weigh its mass as m3, and calculate the concentration of kelp mucus mother liquor as m3 / (m2-m1)×100%.

[0053] Step 5: Take the remaining 950 ml of kelp mucus mother liquor, add water to 5 L of total solution, stir thoroughly for 10 min, and obtain 5 L of kelp mucus drag reducer with a concentration of 0.19×m3 / (m2-m1)×100%.

[0054] Comparative Example 2:

[0055] In this case, dried kelp is used as raw material. After the initial treatment of slices, kelp mucus is extracted without alkali to prepare kelp mucus drag reducer. The specific implementation steps are as follows:

[0056] Step 1: Take 100g of dried kelp and cut it into squares less than 2cm to obtain dried kelp fragments. Add water to dilute the solution to 1L and let it stand for 24h to extract more kelp mucus.

[0057] Step 2: Place the mixture of dry kelp fragments and kelp mucus in a filter to filter and obtain kelp mucus mother liquor.

[0058] Step 3: Take a beaker and weigh its mass m1, take 50 ml of kelp mucus mother solution and add it to the beaker, weigh its mass m2, add 95% ethanol until the ethanol content in the solution is 75%, place the mixed solution in a centrifuge and centrifuge at a speed of 3000r / min for 5 minutes.

[0059] Step 4: Take the precipitate after centrifugation and put it into a vacuum drying oven, dry it at 20°C for 30 minutes to remove moisture, and obtain kelp mucus drag reducer powder. Weigh its mass as m3, and calculate the concentration of kelp mucus mother liquor as m3 / (m2-m1)×100%.

[0060] Step 5: Take the remaining 950 ml of kelp mucus mother liquor, add water to 5 L of total solution, stir thoroughly for 10 min, and obtain 5 L of kelp mucus drag reducer with a concentration of 0.19×m3 / (m2-m1)×100%.

[0061] The kelp mucus drag reducer prepared in Example 1 and Comparative Examples 1 and 2 was tested for drag reduction performance in a homemade rotor resistance tester to test the drag reduction rate of the kelp mucus drag reducer under turbulence of different Re numbers. The results are as follows: Figure 1 shown.

[0062] Depend on Figure 1 The experimental results show that the kelp mucus drag reducer prepared by slicing has better drag reduction effect than the kelp mucus drag reducer prepared by blending. The high-speed shearing action during blending destroys the long-chain molecular structure of the kelp drag reducing material, which makes the drag reduction performance of the kelp drag reducing material ineffective and reduces the drag reduction rate. Compared with blending, the drag reduction rate of the dry kelp mucus drag reducer obtained by slicing increased by 3% to 9%. The kelp mucus drag reducer prepared by alkali extraction has better drag reduction effect than the kelp mucus drag reducer prepared without alkali. Since sodium bicarbonate changes the pH of the solution during extraction and turns the solution into a weak alkaline state, the kelp cell wall is destroyed to extract more kelp polysaccharides, while replacing the alginate in the kelp into kelp polysaccharides. Therefore, the concentration of kelp polysaccharides in the solution increases, and the kelp mucus drag reducer prepared by alkali extraction has a higher drag reduction rate.

[0063] In addition, the drag reduction rate of kelp mucus drag reducer under long-term strong turbulent shear was tested. The kelp mucus drag reducer prepared by alkali extraction treatment had a higher drag reduction rate and its drag reduction rate decreased less than that of the kelp mucus drag reducer prepared without alkali. The alkali extraction treatment increased the concentration of kelp polysaccharides in the drag reducer, so the shear resistance of the kelp mucus drag reducer was enhanced.

[0064] It can be seen from the above embodiments that the kelp mucus drag reducer provided by the present invention has excellent underwater drag reduction performance, and the drag reduction rate of the kelp mucus drag reducer increases with the increase of Re number. In addition, under the continuous shearing action of turbulence of Re=90675 for 40 minutes, the drag reduction rate of about 40% can still be maintained. The kelp mucus drag reducer not only has excellent drag reduction effect under the action of high Re number turbulence, but also the drag reduction effect is not easy to fail for a long time, and has excellent shear resistance, which shows that the kelp mucus drag reducer of the present invention has high flow rate and long-term practical value in the field of underwater drag reduction.

[0065] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and intent of the present invention.

Claims

1. A kelp mucus drag reducer, characterized in that: It includes kelp mucus and sodium bicarbonate, and the mass ratio of kelp mucus: sodium bicarbonate is 100:8-15.

2. The kelp mucus drag reducer according to claim 1, characterized in that: The method for obtaining the kelp mucus is as follows: taking unwashed kelp as raw material, cutting the kelp into thin slices, obtaining kelp fragments and part of the kelp mucus, adding water to dilute, and standing to extract the kelp mucus.

3. A kelp mucus drag reducer according to claim 2, characterized in that: The size of the kelp flakes is no greater than 2cm×2cm×0.5cm.

4. A method for preparing the kelp mucus drag reducer according to any one of claims 1 to 3, characterized in that The specific steps are as follows: Pre-treating kelp as a raw material to obtain kelp mucus; The pretreated kelp mucus is added with sodium bicarbonate powder, the pH value is adjusted to create a weakly alkaline environment, and the kelp mucus mother liquor is obtained by filtering with a filter; Calculate the concentration of kelp mucus mother solution; According to the measured concentration of the kelp mucus mother liquor, the kelp mucus mother liquor is dried and concentrated or diluted with water, and is fully stirred to prepare kelp mucus drag reducers of different concentrations.

5. The method for preparing the kelp mucus drag reducer according to claim 4, characterized in that: The kelp pretreatment method comprises the following steps: taking unwashed kelp as raw material, cutting the kelp into thin slices, obtaining kelp fragments and part of kelp mucus, diluting with water, and standing the slices to extract the kelp mucus.

6. The method for preparing the kelp mucus drag reducer according to claim 5, characterized in that: The size of the kelp slices is no more than 2cm×2cm×0.5cm. The obtained kelp fragments and part of the kelp mucus are diluted with water 10 times the mass of the kelp and then left to stand for 24 hours to extract the kelp mucus.

7. The method for preparing the kelp mucus drag reducer according to claim 4, characterized in that: The sodium bicarbonate powder accounts for 8% to 15% of the mass of the kelp, and makes the solution weakly alkaline without losing the viscosity of the solution, destroys the cell wall and converts alginic acid into seaweed polysaccharide to extract more kelp polysaccharide mucus by standing.

8. The method for preparing the kelp mucus drag reducer according to claim 4, characterized in that: The method for calculating the concentration of the kelp mucus mother liquor is as follows: Taking part of the kelp mucus mother liquor for alcohol precipitation, adding ethanol to part of the kelp mucus mother liquor, precipitating kelp polysaccharide according to the alcohol insolubility of kelp polysaccharide, and subjecting the solution to centrifugal filtration to obtain kelp polysaccharide mucus precipitate; The kelp polysaccharide mucus precipitate was centrifuged and dried, and the dry weight was measured to calculate the concentration of the kelp mucus mother liquor.

9. The method for preparing the kelp mucus drag reducer according to claim 4, characterized in that: The alcohol precipitation method comprises the following steps: adding anhydrous ethanol until the ethanol content in the solution is 70% to 80%, and centrifuging the mother liquor after adding the alcohol at a speed of 2000 r / min to 4000 r / min.

10. An application of the kelp mucus drag reducer according to any one of claims 1 to 3, characterized in that: The kelp mucus drag reducer is released onto the outer surface of the vehicle, where it is diluted by the water flow, and the viscosity of water in the surface flow field increases over time, thereby completing the drag reduction function.

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