Bio-based n-alkane phase change wax as well as preparation method and application thereof

Abstract

The invention discloses bio-based n-alkane phase change wax as well as a preparation method and application thereof, and belongs to the technical field of phase change materials. The preparation method of the bio-based n-alkane phase change wax comprises the following steps: carrying out hydrodeoxygenation catalytic reaction and thin film evaporation-molecular distillation separation by taking grease with the carbon atom number of 20 or 22 as a raw material, so as to obtain the bio-based n-alkane phase change wax, the raw materials are selected from at least one of nannochloropsis oculata oil, high erucic acid rapeseed oil and crambe oil. The preparation method is simple, the bio-based n-alkane phase change wax with higher yield and purity can be obtained, the hydrogen consumption is low, the cost is lower, and the obtained bio-based n-alkane phase change wax has the characteristics of high melting point and high stability, and can be applied to the application fields in a higher temperature range, such as the fields of battery thermal management, intelligent textiles, medical physiotherapy and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of phase change materials, in particular to a bio-based n-alkane phase change wax and a preparation method and application thereof. BACKGROUND

[0002] The prior art usually converts animal and vegetable oils and their derivatives into n-alkanes through a hydrogenation process, but the preparation methods currently adopted usually have limited applicability of raw materials, and in addition, cracking, isomerization and aromatization of hydrocarbons are prone to occur in the hydrogenation deoxygenation and subsequent treatment processes, thereby affecting the yield and purity of n-alkanes. In addition, the existing hydrogenation process has high hydrogen consumption and high cost.

[0003] In view of this, the present application is proposed. SUMMARY

[0004] The present application aims to provide a bio-based n-alkane phase change wax and a preparation method and application thereof to solve or improve the above technical problems.

[0005] The present application can be achieved as follows:

[0006] In a first aspect, the present application provides a preparation method of a bio-based n-alkane phase change wax, comprising the following steps: subjecting oil with 20 carbon atoms or oil with 22 carbon atoms as a raw material to a hydrogenation deoxygenation catalytic reaction and thin film evaporation-molecular distillation separation to obtain a bio-based n-alkane phase change wax.

[0007] The raw material is selected from at least one of microalgae oil, high erucic rapeseed oil and sea kale oil.

[0008] In an optional embodiment, the hydrogenation deoxygenation catalytic reaction conditions include: a temperature of 280℃-360℃, a hydrogen partial pressure of 3MPa-10MPa, a liquid hourly space velocity of 0.5h -1 -3h -1 , a hydrogen-oil volume ratio of 500Nm 3 / m 3 -1500Nm 3 / m 3 , and a catalyst of Ni-Mo / Al2O3 catalyst or Ni-Mo / Al2O3-SAPO-11 catalyst or Ni-Mo / amorphous silica-alumina catalyst.

[0009] In an optional embodiment, the hydrogenation deoxygenation catalytic reaction conditions include: a temperature of 300℃-330℃, a hydrogen partial pressure of 6MPa-8MPa, a liquid hourly space velocity of 1.5h -1 -2h -1 , a hydrogen-oil volume ratio of 1000Nm 3 / m 3 -1300Nm3 / m 3 .

[0010] In an alternative embodiment, the thin-film evaporation-molecular distillation conditions include an evaporation temperature of 70-300℃, a condenser temperature of 30-60℃, a vacuum degree of 0.1-133 Pa, and a wiper rotation speed of 100-500 rpm.

[0011] In an alternative embodiment, the thin-film evaporation-molecular distillation conditions include an evaporation temperature of 100-150℃, a condenser temperature of 40-45℃, a vacuum degree of 1-20 Pa, and a wiper rotation speed of 200-250 rpm.

[0012] In an alternative embodiment, the raw material is high erucic rapeseed oil, and before the hydrogenation and deoxidation reaction, the high erucic rapeseed oil is further preheated, desulfurized, degummed, deacidified, and washed to refine.

[0013] In an alternative embodiment, the raw material is microgreen algae oil, and before the hydrogenation and deoxidation reaction, the microgreen algae oil is further preheated, decolorized, degummed, and solvent refined.

[0014] In an alternative embodiment, the raw material is sea kale oil, and before the hydrogenation and deoxidation reaction, the sea kale oil is further preheated, detoxified, enzymatically hydrolyzed, adsorbed, degummed, and deacidified.

[0015] In a second aspect, the present application provides a bio-based n-alkane phase change wax prepared by the method of any one of the preceding embodiments.

[0016] In an alternative embodiment, the bio-based n-alkane phase change wax has a melting point of no less than 35℃, more preferably 36-44℃.

[0017] In an alternative embodiment, the bio-based n-alkane phase change wax has a latent heat of phase change of no less than 235 J / g, more preferably 239-243 J / g.

[0018] In a third aspect, the present application provides the use of the bio-based n-alkane phase change wax of the preceding embodiments, for example, the use of the bio-based n-alkane phase change wax in battery thermal management, smart textiles, and medical physiotherapy.

[0019] The beneficial effects of the present application include:

[0020] The preparation method of the bio-based normal alkane phase change wax is simple, the hydrogenation and deoxidation catalytic reaction and thin film evaporation-molecular distillation separation are performed on specific raw materials, the bio-based normal alkane phase change wax with high yield and purity can be obtained, the hydrogen consumption is small, and the cost is low. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. If specific conditions are not indicated in the embodiments, conventional conditions or conditions recommended by manufacturers are adopted. If the reagents or instruments are not indicated by the manufacturers, they are all conventional products that can be purchased in the market.

[0022] The bio-based normal alkane phase change wax provided by the present application and the preparation method and application thereof will be described below.

[0023] The present application provides a preparation method of bio-based normal alkane phase change wax, comprising the following steps: performing hydrogenation and deoxidation catalytic reaction and thin film evaporation-molecular distillation separation on oil and fat with carbon atom number of 20 or carbon atom number of 22 as raw materials to obtain bio-based normal alkane phase change wax.

[0024] Among them, the raw material is selected from at least one of microgreen algae oil, high erucic rapeseed oil and sea kale oil. Exemplarily, the erucic acid content of the high erucic rapeseed oil can be 45% to 55%.

[0025] It should be noted that the above method provided by the present application is only applicable to the three raw materials of microgreen algae oil, high erucic rapeseed oil and sea kale oil. The reason is that if the carbon atom content of the raw material is less than 20, the molecular chain is too short, which can easily cause pyrolysis, oxidative decomposition or volatilization of the components in the high-temperature reaction, generate by-products such as aldehydes and ketones, and reduce the selectivity and yield of the target product. If the carbon atom content of the raw material is higher than 22, the contact efficiency of the catalyst and the substrate is significantly reduced due to the too long molecular chain, which leads to a decrease in the reaction rate. In addition, if the carbon atom number of the raw material is 20 or 22, but not microgreen algae oil, high erucic rapeseed oil and sea kale oil (such as peanut oil), the method provided by the present application can easily make the branched or multi-unsaturated acid of these oils and fats occupy the active sites, and inhibit the target reaction.

[0026] The preparation method of the bio-based normal alkane phase change wax provided by the present application is simple, the hydrogenation and deoxidation catalytic reaction and thin film evaporation-molecular distillation separation are performed on specific raw materials, the bio-based normal alkane phase change wax with high yield and purity can be obtained, the hydrogen consumption is small, and the cost is low.

[0027] In some optional embodiments, the temperature of the hydrodeoxygenation catalytic reaction can be 280-360°C, such as 280°C, 285°C, 290°C, 295°C, 300°C, 305°C, 310°C, 315°C, 320°C, 325°C, 330°C, 335°C, 340°C, 345°C, 350°C, 355°C, or 360°C, or other values within the range of 280-360°C. If the temperature of the hydrodeoxygenation catalytic reaction is lower than 280°C, the reaction kinetics is limited, which leads to the inability to break through the energy barrier of C-O bond rupture, reduces the deoxygenation rate, and the accumulation of intermediate products (such as fatty acid aldehydes and ketones) under low-temperature conditions causes carbon chain condensation reactions to generate coke precursors, affecting the selectivity of the reaction and the quality of the product. If the temperature of the hydrodeoxygenation catalytic reaction is higher than 360°C, it will lead to excessive cracking, causing the carbon number distribution of alkane products to shift towards C8-C14, reducing the selectivity and yield of the target product, and high temperatures will also cause the sintering of metal catalyst grains, leading to a decrease in catalyst activity, which in turn affects the reaction efficiency and effect.

[0028] The hydrogen partial pressure of the hydrodeoxygenation catalytic reaction can be 3-10 MPa, such as 3 MPa, 4 MPa, 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa, or 10 MPa, or other values within the range of 3-10 MPa. If the hydrogen partial pressure of the hydrodeoxygenation catalytic reaction is lower than 3 MPa, the hydrogen coverage is insufficient, which leads to the shift of the deoxygenation reaction to dehydration to generate olefins, and the unsaturated intermediates are prone to polymerization, which accelerates the rate of carbon deposition and affects the catalyst activity. If the hydrogen partial pressure of the hydrodeoxygenation catalytic reaction is higher than 10 MPa, hydrogen molecules compete for adsorption excessively, occupy the acid sites, inhibit the protonation of C-O bonds, and hinder the deoxygenation reaction, while the pressure resistance requirement of the equipment increases, and the investment cost increases.

[0029] The liquid hourly space velocity can be 0.5-3 h-1, such as 0.5 h-1, 1 h-1, 1.5 h-1, 2 h-1, 2.5 h-1, or 3 h-1, or other values within the range of 0.5-3 h-1. If the liquid hourly space velocity of the hydrodeoxygenation catalytic reaction is lower than 0.5 h-1, the residence time of the reactants is too long, which easily leads to the secondary cracking of alkanes to generate byproducts, and reduces the processing capacity of the catalyst and the reaction efficiency. If the liquid hourly space velocity of the hydrodeoxygenation catalytic reaction is higher than 3 h-1, the residence time of the reactants is too short, which easily leads to the generation of byproducts and reduces the processing capacity of the catalyst and the reaction efficiency. -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 ​​​​​​​​​​​, the reactant flow rate is too fast, the reactant is insufficiently contacted with the catalyst, the concentration gradient of dissolved hydrogen in the liquid phase is increased, the local deoxygenation rate is significantly different, and the unreacted glyceride blocks the bed pore, further reducing the catalyst activity and reaction efficiency.

[0030] The hydrogen to oil volume ratio can be 500 Nm 3 / m 3 ~ 1500 Nm 3 / m 3 , such as 500 Nm 3 / m 3 , 800 Nm 3 / m 3 , 1000 Nm 3 / m 3 , 1200 Nm 3 / m 3 or 1500 Nm 3 / m 3 , and other values in the range of 500 Nm 3 / m 3 ~ 1500 Nm 3 / m 3 .

[0031] The catalyst can be a Ni-Mo / Al2O3 catalyst or a Ni-Mo / Al2O3-SAPO-11 catalyst or a Ni-Mo / amorphous silica-alumina catalyst. It should be noted that the present application specifically uses the above-mentioned catalysts, which can effectively optimize the n-alkane selectivity and carbon number distribution of the products, and meet the requirements of different application scenarios for product characteristics. The Ni-Mo / Al2O3 catalyst can dominate the direct deoxygenation mechanism due to the strong Lewis acid sites on its surface, rapidly breaking the C-O bond and performing hydrogenation reaction, effectively inhibiting the formation of double bonds, and achieving an n-alkane selectivity of 85% ~ 88%, and its product carbon number distribution is relatively wide (C16 ~ C22). The Ni-Mo / Al2O3-SAPO-11 catalyst can effectively reduce the generation of coke by virtue of the channel constraint effect and weak acid sites of SAPO-11, prolong the catalyst life, the catalyst can achieve an n-alkane selectivity of 92% ~ 95%, and its product carbon number distribution is more concentrated (C18 ~ C22), significantly improving the product purity and quality. And the Ni-Mo / amorphous silica-alumina relies on the large pore structure to accommodate macromolecular diffusion, combined with medium-strong acid to promote hydrogenation deoxygenation (HDO) and retain heavy components.

[0032] In some preferred embodiments, the hydrogenation deoxygenation catalytic reaction conditions can include: temperature 300℃ ~ 330℃, hydrogen partial pressure 6MPa ~ 8MPa, liquid hourly space velocity 1.5h -1 ~ 2h -1, hydrogen oil volume ratio is 1000 Nm 3 / m 3 ~ 1300 Nm 3 / m 3 .

[0033] In some alternative embodiments, the evaporation temperature of the thin-film evaporation-molecular distillation can be 70-300°C, such as 70°C, 100°C, 120°C, 150°C, 180°C, 200°C, 220°C, 250°C, 280°C or 300°C, or other values within the range of 70-300°C. If the evaporation temperature of the thin-film evaporation-molecular distillation is lower than 70°C, the effective vaporization of high-boiling components is not conducive, resulting in a decrease in separation efficiency; if the evaporation temperature of the thin-film evaporation-molecular distillation is higher than 300°C, thermal polymerization or cracking reactions of heat-sensitive substances are easily induced, resulting in changes in the physical and chemical properties of the product, such as an increase in color.

[0034] The condenser temperature can be 30-60°C, such as 30°C, 35°C, 40°C, 45°C, 50°C, 55°C or 60°C, or other values within the range of 30-60°C. If the condenser temperature of the thin-film evaporation-molecular distillation is lower than 30°C, the condensing surface is prone to frost, increasing the heat transfer resistance and resulting in a decrease in condensation efficiency; if the condenser temperature of the thin-film evaporation-molecular distillation is higher than 60°C, the light components will be difficult to completely condense, and the uncondensed light component vapor will be discharged from the system with the tail gas, thereby increasing the loss rate of light components and leading to an increase in the load of the vacuum system.

[0035] The vacuum degree can be 0.1-133 Pa, such as 0.1 Pa, 0.5 Pa, 1 Pa, 5 Pa, 10 Pa, 20 Pa, 50 Pa, 80 Pa, 100 Pa, 120 Pa or 133 Pa, or other values within the range of 0.1-133 Pa. If the vacuum degree of the thin-film evaporation-molecular distillation is higher than 133 Pa, the boiling temperature of the material will increase, thereby causing the evaporation temperature to be simultaneously elevated, which can promote the increase in thermal decomposition by-products.

[0036] The scraping membrane rotation speed can be 100-500 rpm, such as 100 rpm, 150 rpm, 200 rpm, 250 rpm, 300 rpm, 350 rpm, 400 rpm, 450 rpm or 500 rpm, or other values within the range of 100-500 rpm. If the scraping membrane rotation speed of the thin-film evaporation-molecular distillation is lower than 100 rpm, the liquid film thickness will increase, resulting in a decrease in the heat transfer coefficient and thereby a decrease in the evaporation rate; if the scraping membrane rotation speed of the thin-film evaporation-molecular distillation is higher than 500 rpm, excessive mechanical shear force will cause the liquid film to break, reducing the separation uniformity and accelerating the wear of the bearing.

[0037] In some preferred embodiments, the thin-film evaporation-molecular distillation conditions include: an evaporation temperature of 100-150°C, a condenser temperature of 40-45°C, a vacuum degree of 1-20 Pa, and a scraper rotation speed of 200-250 rpm.

[0038] In some alternative embodiments, the raw material is high erucic rapeseed oil, and before the hydrogenation and deoxygenation reaction, the high erucic rapeseed oil is further subjected to preheating, desulfurization, degumming, deacidification, and water washing.

[0039] Preheating can be heating the high erucic rapeseed oil to 55-65°C.

[0040] Desulfurization can be adding an adsorbent, stirring at 55-65°C for 1-2 h, filtering, and removing sulfides and the adsorbent. The adsorbent can include zinc powder and activated clay, the zinc powder can be added in an amount of 0.4-0.6 wt% of the high erucic rapeseed oil, and the particle size of the zinc powder can be about 200 mesh; the activated clay can be added in an amount of 0.5-1.5 wt% of the high erucic rapeseed oil; and the zinc powder and the activated clay are sequentially added to the high erucic rapeseed oil.

[0041] Degumming can be adding phosphoric acid with a concentration of 84-86%, stirring at 55-65°C for 25-35 min; then adding salt water (salt to water mass ratio can be 2.5:100 to 3.5:100) at 60-70°C, stirring for 15-25 min, and standing for 1.5-2.5 h to remove the lower gum phase to obtain the initial degummed oil. The amount of phosphoric acid added can be 1.5-2.5 wt‰ of the high erucic rapeseed oil; and the amount of salt water added can be 4.5-5.5 wt% of the high erucic rapeseed oil.

[0042] Deacidification can be slowly adding 4-6% sodium hydroxide solution to the oil after degumming, and neutralizing to a pH value of 7.5-8.0. After standing for at least 6 h, centrifugal separation of the soapstock is performed to obtain neutralized and deacidified oil.

[0043] Water washing can be heating the neutralized and deacidified oil to 75-85°C, adding 70-80°C salt soft water (salt to water mass ratio can be 0.4:100 to 0.6:100), and stirring for 10-20 min. The amount of salt soft water added can be 4-6 wt% of the high erucic rapeseed oil. After stopping stirring, standing for 1 h or so, and repeating the above operation, deionized water is used until the water phase conductivity is <50 μS / cm. Dehydration is performed at a vacuum degree of -0.098 MPa, a temperature of 105-115°C, and water content ≤0.05% to obtain refined rapeseed oil.

[0044] In some alternative embodiments, the raw material is microalgae oil, and before the hydrodeoxygenation reaction, the microalgae oil is preheated, decolorized, degummed, and solvent refined.

[0045] For example, the preheating can be heating the microalgae oil to 60-70°C.

[0046] The decolorization can be adding an adsorbent to the preheated microalgae oil, stirring at 300-400 rpm for 35-45 min, and then stirring at 100-140 rpm for 45-55 min to ensure sufficient adsorption. The adsorbent can be lignin-based activated carbon, and the lignin-based activated carbon can be added in an amount of 3.5-4.0% (w / v) of the microalgae oil.

[0047] The degumming can be adding deionized water to the decolorized microalgae oil at an oil-to-water ratio (volume ratio) of 1:1.1 to 1:1.3, ultrasonic emulsifying at 40-50°C for 10-20 min to disperse the oil in the water and dissolve small molecular impurities in the water, adding a coagulant to promote oil coagulation and precipitation, and centrifuging. The coagulant can be polyferric sulfate, and the polyferric sulfate can be added in an amount of 0.4-0.6 wt% of the microalgae oil.

[0048] The solvent refining can be adding anhydrous ethanol at a ratio of 2.5:1 to 3.5:1 (volume ratio) to redissolve the precipitated oil, statically crystallizing at -10.5 to -9.5°C for 7.5-8.5 h to remove solid impurities by filtration, and increasing the oil recovery rate. Finally, the solvent is removed by evaporation under a vacuum of -0.095 to -0.10 MPa and a temperature of 48-52°C to obtain high-purity oil.

[0049] In some alternative embodiments, the raw material is sea kale oil, and before the hydrodeoxygenation reaction, the sea kale oil is preheated, detoxified, enzymatically hydrolyzed, adsorbed, degummed, and deacidified.

[0050] For example, the preheating can be heating the sea kale oil to 55-65°C.

[0051] The detoxification can be adding 0.5-1.5 wt% of black mustard enzyme, reacting at a pH of 5.0-6.0 and a temperature of 45-55°C for 2-4 h to catalyze the hydrolysis of glucosinolates to generate isothiocyanates and other products. Then, 3-5 wt% of activated white clay is added and stirred at 60-70°C for 30 min to effectively adsorb the isothiocyanates, thereby achieving detoxification.

[0052] The enzymatic hydrolysis can be adding β-glucosidase (enzyme activity ≥ 800 U / g), adjusting the pH to 5.1-5.3 with citric acid-phosphate buffer, and hydrolyzing at 40-50°C for 3.5-4.5h to decompose the cyanide into non-toxic products. In this process, the enzyme activity of β-glucosidase is ≥ 800 U / g, and the addition amount can be 0.05-0.15wt% of the sea kale oil.

[0053] The adsorption can be adding an adsorbent, and then filtering after adsorbing at 55-65°C for 0.5-1.5h to adsorb the cyanide generated by hydrolysis. In this process, the adsorbent can be diatomite with a mesh size of about 400, and the addition amount of diatomite can be 2.5-3.5wt% of the sea kale oil.

[0054] The degumming and deacidification can be related operations of high erucic acid rapeseed oil.

[0055] The above series of operations for pretreating the raw materials are beneficial to improving the yield and purity of the bio-based n-alkane phase change wax.

[0056] Based on the above, the preparation method of the bio-based n-alkane phase change wax provided by the present application is simple, and the bio-based n-alkane phase change wax with high yield and purity can be obtained, and the hydrogen consumption is low.

[0057] Specifically, the reason why the present application can avoid the cracking, isomerization and aromatization of hydrocarbons during the hydrogenation and subsequent treatment is that the catalyst used in the present application has a unique active center and pore structure, which can realize highly selective hydrogenation and deoxidation. In addition, by controlling the reaction conditions, including the reaction temperature, pressure and space velocity, the reaction is carried out under suitable conditions, which further reduces the probability of occurrence of side reactions, thereby ensuring that the method of the present application can obtain n-alkanes with high yield and purity. In addition, the method provided by the present application significantly improves the utilization rate of hydrogen by using an efficient catalyst system and optimizing the reaction conditions, avoiding the problem of high hydrogen consumption in the existing hydrogenation process, thereby effectively reducing the cost.

[0058] Correspondingly, the present application also provides a bio-based n-alkane phase change wax, which is prepared by the above preparation method.

[0059] In optional embodiments, the melting point of the bio-based n-alkane phase change wax is not less than 35°C, for example, it can be 36-44°C.

[0060] In optional embodiments, the latent heat of phase change of the bio-based n-alkane phase change wax is not less than 235 J / g, for example, it can be 239-243 J / g.

[0061] The bio-based n-alkane phase change wax has high melting point and high stability, and can be applied to application fields of higher temperature range.

[0062] Correspondingly, the application also provides an application of the bio-based n-alkane phase change wax, for example, the bio-based n-alkane phase change wax is applied to fields of battery thermal management, intelligent textiles and medical physiotherapy.

[0063] The features and performances of the application are further described in detail below in combination with examples.

[0064] Example 1

[0065] The example provides a bio-based n-alkane phase change wax, and a preparation method thereof comprises the following steps:

[0066] S1: preheating.

[0067] High erucic rapeseed oil (erucic acid content is 50%) is heated to 60°C.

[0068] S2: desulfurization.

[0069] 0.5wt% zinc powder (200 mesh) and 1wt% activated clay are sequentially added to the preheated high erucic rapeseed oil, stirred at 60°C for 1h, filtered, and the sulfides, zinc powder and activated clay are removed.

[0070] S3: degumming.

[0071] 2wt‰ of 85% concentration phosphoric acid is added to the desulfurized high erucic rapeseed oil, stirred at 60°C for 30min; then 5% of 65°C salt water (mass ratio of salt to water is 3:100) of high erucic rapeseed oil is added, stirred for 20min, and settled for 2h, and the lower gum phase is removed to obtain the initial degummed oil.

[0072] S4: deacidification.

[0073] 5wt% of sodium hydroxide solution is slowly added to the initial degummed oil, and neutralized to pH 7.8. After settling for 6h, the soapstock is separated by centrifugation to obtain the neutralized and deacidified oil.

[0074] S5: water washing and refining.

[0075] The neutralized and deacidified oil is heated to 80°C, and 5% of 75°C salt soft water (mass ratio of salt to water is 0.5:100) of high erucic rapeseed oil is added, and stirred for 15min. After stopping stirring, it is settled for 1h, and the above operation is repeated, and deionized water is used until the water phase conductivity is <50μS / cm. Under the conditions of vacuum degree of-0.098MPa and temperature of 110°C, dehydration is performed until the moisture content is ≤0.05%, and refined rapeseed oil is obtained.

[0076] S6: Hydrodeoxygenation.

[0077] The refined rapeseed oil was subjected to hydrodeoxygenation reaction under the conditions of a reaction temperature of 330℃, a hydrogen partial pressure of 7MPa, a liquid hourly space velocity of 1.5h-1, and a hydrogen to oil volume ratio of 1300Nm3 / m. -1 3 3 The refined rapeseed oil was subjected to hydrodeoxygenation reaction under the conditions of a reaction temperature of 330℃, a hydrogen partial pressure of 7MPa, a liquid hourly space velocity of 1.5h-1, and a hydrogen to oil volume ratio of 1300Nm3 / m.

[0078] S7: Molecular distillation.

[0079] The product after hydrodeoxygenation was subjected to thin-film evaporation-molecular distillation, with a temperature setting of 130℃, a vacuum degree of 10Pa, a scraper membrane rotation speed of 200rpm, a condensation temperature of 45℃, and a cold trap temperature of -20℃.

[0080] Example 2

[0081] The present embodiment provides a bio-based n-alkane phase change wax, and a preparation method thereof, which comprises:

[0082] S1: Preheating.

[0083] The high erucic rapeseed oil (erucic acid content of 45%) was heated to 55℃.

[0084] S2: Desulfurization.

[0085] To the preheated high erucic rapeseed oil, 0.4wt% zinc powder (200 mesh) and 0.5wt% activated clay were added in sequence, stirred at 55℃ for 2h, filtered, and the sulfides and zinc powder and activated clay were removed.

[0086] S3: Degumming.

[0087] To the desulfurized high erucic rapeseed oil, 2wt‰ of phosphoric acid with a concentration of 84% was added, and stirred at 55℃ for 35min; then 4.5% of 60℃ salt water (mass ratio of salt to water was 2.5:100) based on the mass of high erucic rapeseed oil was added, stirred for 25min, and settled for 1.5h, and the lower gum phase was removed to obtain the primary degummed oil.

[0088] S4: Deacidification.

[0089] To the primary degummed oil, 4wt% of sodium hydroxide solution was slowly added, and neutralized to a pH value of 8.0. After 8h of precipitation, the soapstock was separated by centrifugation to obtain the neutralized deacidified oil.

[0090] S5: Water washing and refining.

[0091] ​​The neutralized and deacidified oil was warmed to 75℃, and 4% of the mass of the oil of 70℃ soft water of salt (mass ratio of salt to water was 0.4:100) was added, and stirred for 20 min. After stopping stirring, the precipitate was allowed to settle for 1 h, and the above operation was repeated using deionized water until the conductivity of the aqueous phase was <50 μS / cm. Dewatering was performed under a vacuum of -0.098 MPa and a temperature of 105℃ until the moisture content was ≤0.05%, to obtain refined rapeseed oil.

[0092] S6: Hydrodeoxygenation.

[0093] The refined rapeseed oil was subjected to hydrodeoxygenation using a sulfur-tolerant Ni-Mo / Al2O3 catalyst under the following conditions: a reaction temperature of 300℃, a hydrogen partial pressure of 6 MPa, a liquid hourly space velocity of 1.5 h-1, and a hydrogen to oil volume ratio of 1000 Nm3 / m3. -1 3 3 S7: Molecular distillation.

[0094] S7: Molecular distillation.

[0095] The product after hydrodeoxygenation was subjected to thin-film evaporation-molecular distillation, with a temperature setting of 70℃, a vacuum degree of 0.1 Pa, a scraper membrane rotation speed of 100 rpm, a condensation temperature of 30℃, and a cold trap temperature of -20℃.

[0096] Example 3

[0097] This example provides a bio-based n-alkane phase change wax, and a method for preparing the same, which comprises:

[0098] S1: Preheating.

[0099] The high-erucic rapeseed oil (erucic acid content of 55%) was heated to 65℃.

[0100] S2: Desulfurization.

[0101] To the preheated high-erucic rapeseed oil, 0.6wt% zinc powder (200 mesh) and 1.5wt% activated clay were added in sequence, and stirred at 65℃ for 1 h, and filtered to remove sulfides and zinc powder and activated clay.

[0102] S3: Degumming.

[0103] To the desulfurized high-erucic rapeseed oil, 2wt‰ of phosphoric acid with a concentration of 86% was added, and stirred at 65℃ for 25 min; then 5.5% of the mass of the oil of 70℃ soft water of salt (mass ratio of salt to water was 3.5:100) was added, and stirred for 15 min, and allowed to settle for 2.5 h, and the lower gum phase was removed, to obtain a primary degummed oil.

[0104] S4: Deacidification.

[0105] ​​Slowly add 6wt% sodium hydroxide solution to the oil after primary degumming to neutralize it to a pH of 7.5. After settling for 10 hours, centrifuge and separate the soap stock to obtain neutralized deacidified oil.

[0106] S5: water washing and refining.

[0107] The neutralized, deacidified oil was heated to 85°C, and 80°C soft salt water (6% by weight of the high-erucic acid rapeseed oil) was added (the mass ratio of salt to water was 0.6:100) and stirred for 10 minutes. After stopping stirring, the oil was allowed to settle for 1 hour. The above process was repeated, using deionized water until the aqueous phase conductivity was less than 50 μS / cm. The oil was then dehydrated to a moisture content of ≤0.05% under vacuum at -0.098 MPa and a temperature of 115°C to obtain refined rapeseed oil.

[0108] S6: Hydrodeoxygenation.

[0109] Using sulfur-tolerant Ni-Mo / Al2O3 catalyst, the reaction temperature was 330℃, the hydrogen partial pressure was 8MPa, and the liquid hourly space velocity was 2h -1 And the hydrogen-oil volume ratio is 1300Nm 3 / m 3 Under the conditions of , the refined rapeseed oil was subjected to hydrodeoxygenation reaction.

[0110] S7: Molecular distillation.

[0111] The product after hydrodeoxygenation was subjected to thin film evaporation-molecular distillation with the temperature set at 150°C, the vacuum degree at 20 Pa, the scraping speed at 250 rpm, the condensation temperature at 45°C, and the cold trap temperature at -20°C.

[0112] Example 4

[0113] S1: Preheating.

[0114] Heat the Nannochloropsis oil to 65°C.

[0115] S2: Decolorization.

[0116] Lignin-based activated carbon was added to the preheated Nannochloropsis oil at an amount of 3.8% (w / v), and the mixture was stirred at 350 rpm for 40 min and then at 120 rpm for 50 min.

[0117] S3: Degumming.

[0118] Deionized water was added to the bleached oil at a 1:1.2 (v / v) oil-water ratio. Ultrasonic emulsification was performed at 45°C for 15 minutes to fully disperse the oil and dissolve small molecular impurities. Polyferric sulfate (PFS), a coagulant, was added at 0.5 wt% of the oil to promote oil coagulation and precipitation, followed by centrifugation.

[0119] S4: Solvent refining.

[0120] Anhydrous ethanol was added at a ratio of 3:1 (v / v) to redissolve the precipitated oil, and the oil was statically crystallized at -10°C for 8h. The solid impurities were removed by filtration to improve the recovery rate of the oil. Finally, the solvent was removed by evaporation under a vacuum of -0.098 MPa and a temperature of 50°C to obtain high-purity oil.

[0121] S5: Hydrodeoxygenation.

[0122] The Ni-Mo / Al2O3-SAPO-11 catalyst was used for the hydrodeoxygenation reaction of high-purity Nannochloropsis oil under the optimized conditions of a reaction temperature of 320°C, a hydrogen partial pressure of 6 MPa, a liquid hourly space velocity of 2.0 h -1 -1 3 / m 3 and a hydrogen to oil volume ratio of 1000 Nm

[0123] S6: Molecular distillation.

[0124] The product after hydrodeoxygenation was subjected to thin-film evaporation-molecular distillation with a temperature setting of 115°C, a vacuum degree of 20 Pa, a scraper membrane rotation speed of 200 rpm, a condensation temperature of 40°C, and a cold trap temperature of -20°C.

[0125] Example 5

[0126] S1: Preheating.

[0127] The Nannochloropsis oil was heated to 60°C.

[0128] S2: Decolorization.

[0129] Lignin-based activated carbon was added to the preheated Nannochloropsis oil at an amount of 3.5% (w / v), and was first stirred at a rotation speed of 300 rpm for 45 min and then stirred at 100 rpm for 55 min.

[0130] S3: Degumming.

[0131] Deionized water was added to the decolorized oil at an oil to water ratio of 1:1.1 (v / v), and ultrasonic emulsification was performed at 40°C for 20 min to fully disperse the oil in water and dissolve the small molecular impurities in water. A coagulant, polyferric sulfate (PFS), was added at an amount of 0.4 wt% of the oil to promote the coagulation and precipitation of the oil, and centrifugal separation was performed.

[0132] S4: Solvent refining.

[0133] The precipitated oil was redissolved by adding anhydrous ethanol at a ratio of 2.5:1 (v / v). The product was then statically crystallized at -10.5°C for 8.5 hours. Solid impurities were removed by filtration to improve oil recovery. Finally, the solvent was evaporated at a vacuum of -0.095 MPa and a temperature of 48°C to obtain a high-purity oil.

[0134] S5: Hydrodeoxygenation.

[0135] Using Ni-Mo / Al2O3-SAPO-11 catalyst, the reaction temperature was 300℃, the hydrogen partial pressure was 6MPa, and the liquid hourly space velocity was 1.5h -1 And the hydrogen-oil volume ratio is 1000Nm 3 / m 3 Under the optimized conditions, high-purity Nannochloropsis oil was subjected to hydrodeoxygenation reaction.

[0136] S6: Molecular distillation.

[0137] The product after hydrodeoxygenation was subjected to thin film evaporation-molecular distillation with the temperature set at 70°C, the vacuum degree at 0.1 Pa, the scraping speed at 100 rpm, the condensation temperature at 30°C, and the cold trap temperature at -20°C.

[0138] Example 6

[0139] S1: Preheating.

[0140] Heat the Nannochloropsis oil to 70°C.

[0141] S2: Decolorization.

[0142] The lignin-based activated carbon was added to the preheated Nannochloropsis oil at an amount of 4.0% (w / v), and stirred at 400 rpm for 35 min and then at 140 rpm for 45 min.

[0143] S3: Degumming.

[0144] Deionized water was added to the bleached oil at a 1:1.3 (v / v) oil-water ratio. Ultrasonic emulsification was performed at 50°C for 10 minutes to fully disperse the oil and dissolve small molecular impurities. Polyferric sulfate (PFS), a coagulant, was added at 0.6 wt% of the oil to promote oil coagulation and precipitation, followed by centrifugation.

[0145] S4: Solvent refining.

[0146] The precipitated oil was redissolved by adding anhydrous ethanol at a ratio of 3.5:1 (v / v). The product was then statically crystallized at -9.5°C for 7.5 hours. The solid impurities were then filtered to improve oil recovery. Finally, the solvent was evaporated at a vacuum of -0.10 MPa and a temperature of 52°C to obtain a high-purity oil.

[0147] S5: Hydrodeoxygenation.

[0148] Using Ni-Mo / Al2O3-SAPO-11 catalyst, the reaction temperature was 330℃, the hydrogen partial pressure was 8MPa, and the liquid hourly space velocity was 2.0h -1 And the hydrogen-oil volume ratio is 1300Nm 3 / m 3 Under the optimized conditions, high-purity Nannochloropsis oil was subjected to hydrodeoxygenation reaction.

[0149] S6: Molecular distillation.

[0150] The product after hydrodeoxygenation was subjected to thin film evaporation-molecular distillation with the temperature set at 150°C, the vacuum degree at 20 Pa, the scraping speed at 250 rpm, the condensation temperature at 45°C, and the cold trap temperature at -20°C.

[0151] Example 7

[0152] S1: Preheating.

[0153] Heat crambe oil to 60°C.

[0154] S2: Detoxification.

[0155] Preheated marine glycerol was added with 1 wt% myrosinase and reacted at a pH of 5.5 and 50°C for 3 hours to catalyze the hydrolysis of glucosinolates to produce isothiocyanates and other products. Subsequently, 4 wt% activated clay was added for adsorption at 65°C for 30 minutes with stirring, effectively adsorbing the isothiocyanates and achieving detoxification.

[0156] S3: Enzymatic hydrolysis.

[0157] β-glucosidase (enzyme activity ≥ 800 U / g) was added according to 0.1 wt% of the marine blue glycerol, the pH value was adjusted to 5.2 with citric acid-phosphate buffer, and hydrolyzed at 45° C. for 4 h to decompose cyanogenic glycosides into non-toxic products.

[0158] S4: Adsorption.

[0159] Add 400 mesh diatomaceous earth according to 3 wt% of sea blue glycerol, stir and adsorb at 60°C for 1 hour, and then filter to adsorb cyanide produced by hydrolysis.

[0160] S5: Degumming.

[0161] Add 2wt‰ of 85% phosphoric acid to the adsorbed sea blue glycerol and stir at 60°C for 30 minutes; then add 65°C salt water (the mass ratio of salt to water is 3:100) at 5% of the mass of sea blue glycerol, stir for 20 minutes, let it stand and settle for 2 hours, remove the lower colloid phase, and obtain the primary degummed oil.

[0162] S6: Deacidification.

[0163] Slowly add 5wt% sodium hydroxide solution to the initial degummed oil, and neutralize to pH 7.8. After 6h of precipitation, centrifugal separation of the soapstock is obtained, and neutralized deacidified oil is obtained.

[0164] S7: Hydrodeoxygenation.

[0165] After pre-sulfurization treatment, heat the sea kale oil to 300℃, maintain the hydrogen partial pressure at 8MPa, the liquid hourly space velocity at 1.5h -1 , and the hydrogen-oil volume ratio at 1200Nm 3 / m 3 , to perform the hydrodeoxygenation reaction on the sea kale oil.

[0166] S8: Molecular distillation.

[0167] Perform thin film evaporation-molecular distillation on the hydrodeoxygenated product, set the temperature at 100℃, the vacuum degree at 1Pa, the scraping membrane rotation speed at 250rpm, the condensation temperature at 45℃, and the cold trap temperature at -20℃.

[0168] Example 8

[0169] S1: Preheating.

[0170] Heat the sea kale oil to 55℃.

[0171] S2: Detoxification.

[0172] Add 0.5wt% of black mustard enzyme to the preheated sea kale oil, and react for 4h at pH 5.0 and 45℃, to catalyze the hydrolysis reaction of glucosinolate and generate isothiocyanate and other products. Subsequently, use 3%wt% activated white clay to stir and adsorb at 60℃ for 30min, to effectively adsorb isothiocyanate and achieve detoxification.

[0173] S3: Enzymatic hydrolysis.

[0174] Add 0.05wt% of β-glucosidase (enzyme activity ≥800U / g) to the sea kale oil, adjust the pH value to 5.1 with citric acid-phosphate buffer, and hydrolyze at 40℃ for 4.5h to decompose cyanide into non-toxic products.

[0175] S4: Adsorption.

[0176] Add 400-mesh diatomite at 2.5wt% of the sea kale oil, stir and adsorb at 55℃ for 1.5h, and then filter to adsorb the cyanide generated by hydrolysis.

[0177] S5 to S8: Same as Example 2.

[0178] Example 9

[0179] S1: Preheating

[0180] The sea kale oil was heated to 65°C.

[0181] S2: Detoxification

[0182] The preheated sea kale glycerin was added with 1.5 wt% of black mustard enzyme, and reacted for 2 hours at a pH of 6.0 and a temperature of 55°C to catalyze the hydrolysis of glucosinolates to produce isothiocyanates and other products. Subsequently, 5 wt% activated white clay was used to stir and adsorb for 30 min at 70°C to effectively adsorb isothiocyanates, thereby achieving detoxification.

[0183] S3: Enzymatic hydrolysis

[0184] Beta-glucosidase (enzyme activity ≥ 800 U / g) was added at 0.15 wt% of sea kale glycerin, and the pH was adjusted to 5.3 with citric acid-phosphate buffer, and hydrolyzed for 3.5 h at 50°C to decompose cyanogens into non-toxic products.

[0185] S4: Adsorption

[0186] 400-mesh diatomite was added at 3.5 wt% of sea kale glycerin, and after stirring and adsorbing for 0.5 h at 65°C, it was filtered to adsorb the cyanide produced by hydrolysis.

[0187] S5 to S8: Same as Example 3.

[0188] Comparative Example 1

[0189] The difference between this comparative example and Example 1 is that:

[0190] S6: Hydrodeoxygenation

[0191] A sulfur-tolerant Ni-Mo / Al2O3 catalyst was used to perform hydrodeoxygenation at a reaction temperature of 360°C, a hydrogen partial pressure of 8 MPa, a liquid hourly space velocity of 1.0 h -1 , and a hydrogen to oil volume ratio of 1000 Nm 3 / m 3 .

[0192] S7: Separation

[0193] Under a pressure of 0.5 kPa and a column bottom temperature of 270±5°C, gradient reflux ratio (4:1→1:1) rectification separation was performed to obtain a C20-C22 alkane fraction.

[0194] Comparative Example 2

[0195] The difference between this comparative example and Example 1 is that high erucic rapeseed oil is replaced with soybean oil.

[0196] Comparative Example 3

[0197] The difference between this comparative example and Example 1 is that the high erucic rapeseed oil is replaced by palm oil.

[0198] Comparative Example 4

[0199] The difference between this comparative example and Example 1 is that the high erucic rapeseed oil is replaced by castor oil.

[0200] Comparative Example 5

[0201] The difference between this comparative example and Example 1 is that the high erucic rapeseed oil is replaced by peanut oil.

[0202] Comparative Example 6

[0203] The difference between this comparative example and Example 1 is that the catalyst is Ni-Mo / HZSM-5.

[0204] Comparative Example 7

[0205] The difference between this comparative example and Example 1 is that the temperature of the hydrodeoxygenation catalytic reaction is 380°C.

[0206] Comparative Example 8

[0207] The difference between this comparative example and Example 1 is that the hydrogen partial pressure of the hydrodeoxygenation catalytic reaction is 2 MPa.

[0208] Comparative Example 9

[0209] The difference between this comparative example and Example 1 is that the hydrogen partial pressure of the hydrodeoxygenation catalytic reaction is 15 MPa.

[0210] Comparative Example 10

[0211] The difference between this comparative example and Example 1 is that the liquid hourly space velocity of the hydrodeoxygenation catalytic reaction is 3.5 h -1 .

[0212] Comparative Example 11

[0213] The difference between this comparative example and Example 1 is that there is no S7 step.

[0214] Comparative Example 12

[0215] The difference between this comparative example and Example 1 is that the vacuum degree of the thin-film evaporation-molecular distillation is 150 Pa.

[0216] Comparative Example 13

[0217] The difference between this comparative example and Example 1 is that there are no S1 to S5 steps.

[0218] Test Example

[0219] The phase change waxes prepared in Examples 1-9 and Comparative Examples 1-13 were compared, and the results are shown in Table 1. Among them, the melting point and the phase change latent heat were determined by the DSC method.

[0220] Table 1 Comparison Table

[0221]

[0222] As can be seen from Table 1, Examples 1-9 can all obtain bio-based n-alkane phase change wax with high purity and yield, and the obtained bio-based n-alkane phase change wax has high melting point and phase change latent heat, and the hydrogen consumption in the whole preparation process is less.

[0223] As can be seen from Example 1 and Comparative Example 1, the preparation method provided in Example 1 can obtain higher purity and yield, and the n-docosane prepared in Example 1 has significantly higher phase change latent heat than the n-docosane prepared in Comparative Example 1.

[0224] As can be seen from Example 1 and Comparative Examples 2-5, the method provided in the present application is not suitable for other oils and fats, even the peanut oil with 20 carbon atoms is not suitable.

[0225] As can be seen from Example 1 and Comparative Examples 6-13, the preparation method provided in the present application needs to be prepared under specific conditions to obtain bio-based n-alkane phase change wax with high purity, yield, melting point, and phase change latent heat and less hydrogen consumption.

[0226] In summary, the preparation method of the bio-based n-alkane phase change wax provided in the present application is simple, can obtain bio-based n-alkane phase change wax with high yield and purity, has less hydrogen consumption, and the obtained bio-based n-alkane phase change wax has high melting point and high stability, and can be applied to higher temperature range application fields, such as battery thermal management, intelligent textiles, medical physiotherapy, etc.

[0227] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a bio-based normal alkane phase change wax, characterized in that: The method comprises the following steps: subjecting oil with 20 or 22 carbon atoms as raw material to a catalytic hydrodeoxygenation reaction and thin film evaporation-molecular distillation separation to obtain bio-based normal alkane phase change wax; The raw material is selected from at least one of Nannochloropsis oil, high-erucic acid rapeseed oil and crambe oil.

2. The preparation method according to claim 1, characterized in that The hydrodeoxygenation catalytic reaction conditions include: temperature of 280℃~360℃, hydrogen partial pressure of 3MPa~10MPa, liquid hourly volume space velocity of 0.5h -1 ~3h -1 , hydrogen to oil volume ratio is 500Nm 3 / m 3 ~1500Nm 3 / m 3 The catalyst used is Ni-Mo / Al2O3 catalyst or Ni-Mo / Al2O3-SAPO-11 catalyst or Ni-Mo / amorphous silicon-aluminum catalyst.

3. The preparation method according to claim 2, characterized in that The hydrodeoxygenation catalytic reaction conditions include: temperature of 300℃~330℃, hydrogen partial pressure of 6MPa~8MPa, liquid hourly volume space velocity of 1.5h -1 ~2h -1 , hydrogen to oil volume ratio is 1000Nm 3 / m 3 ~1300Nm 3 / m 3 .

4. The preparation method according to claim 1, characterized in that Thin film evaporation-molecular distillation conditions include: evaporation temperature of 70° C. to 300° C., condenser temperature of 30° C. to 60° C., vacuum degree of 0.1 Pa to 133 Pa, and film scraping speed of 100 rpm to 500 rpm.

5. The preparation method according to claim 4, characterized in that Thin film evaporation-molecular distillation conditions include: evaporation temperature of 100° C. to 150° C., condenser temperature of 40° C. to 45° C., vacuum degree of 1 Pa to 20 Pa, and film scraping speed of 200 rpm to 250 rpm.

6. The preparation method according to claim 1, characterized in that The raw material is high-erucic acid rapeseed oil. Before the hydrodeoxygenation catalytic reaction, the high-erucic acid rapeseed oil is preheated, desulfurized, degummed, deacidified and water-washed for refinement.

7. The preparation method according to claim 1, characterized in that The raw material is Nannochloropsis algae oil. Before the hydrodeoxygenation catalytic reaction, the Nannochloropsis algae oil is preheated, decolorized, degummed and solvent refined.

8. The preparation method according to claim 1, characterized in that The raw material is crambe oil. Before the hydrogenation and deoxygenation catalytic reaction, the crambe oil is preheated, detoxified, enzymatically hydrolyzed, adsorbed, degummed and deacidified.

9. A bio-based normal alkane phase change wax, characterized in that: Prepared by the preparation method according to any one of claims 1 to 8; Preferably, the melting point of the bio-based normal alkane phase change wax is not less than 35°C, more preferably 36°C to 44°C; Preferably, the phase change latent heat of the bio-based normal alkane phase change wax is not less than 235 J / g, more preferably 239 J / g to 243 J / g.

10. A use of the bio-based normal alkane phase change wax according to claim 9, characterized in that: The bio-based normal alkane phase change wax is used in battery thermal management, smart textiles and medical therapy.

Images