WO2020133849A1 - Hybrid adsorbent and application thereof, and method and equipment for treating polyunsaturated fatty acid - Google Patents

Abstract

The present invention relates to the field of polyunsaturated fatty acid treatment, and disclosed thereby are a hybrid adsorbent and an application thereof, and a method and equipment for treating polyunsaturated fatty acid. Said hybrid adsorbent contains aluminum oxide and copper salt modified zeolite molecular sieves, and preferably further contains at least one of argil, attapulgite, silicon dioxide and activated carbon. The aluminum oxide is neural aluminum oxide and/or acidic aluminum oxide. The hybrid adsorbent provided by the present invention is supplemented by ultrasonic activation, and accordingly is comparable to silica gel in the aspects of decolorization and aldehyde ketone quinone removal, and basically will not result in loss of other nutritional components in grease. Meanwhile, the merits of low cost, easy regeneration and good product stability are still retained.

Description

Mixed adsorbent, its application and processing method and equipment for polyunsaturated fatty acid Technical field

The invention belongs to the field of polysaturated fatty acid treatment, and specifically discloses a mixed adsorbent and its application and polyunsaturated fatty acid treatment method and equipment.

Background technique

Unsaturated fatty acids such as DHA and ARA are mainly derived from fish oil and algae oil. Most of them exist in the form of ethyl ester in fish oil, and most of them exist in the form of triglyceride in algae oil. Utilization, safety, stability and other aspects have great advantages. The use of microbial fermentation to produce algae oil overcomes the shortcomings of traditional deep-sea fish oil sources such as limited resources, low yield, and vulnerability to pollution. It has the advantages of easy large-scale fermentation and culture, easy separation and purification, short production cycle, and high polyunsaturated fatty acid content. At present, the microbial cell oil produced by biological fermentation engineering technology is already an ideal substitute for fish oil. Marine microbes such as Schizochytrium, Thraustochytrium, Schizochytrium kotsui have become several major strains of unsaturated fatty acid production.

Commonly used methods of decolorization of unsaturated fatty acid esters include: physical adsorption, chemical decolorization, membrane decolorization, light energy decolorization, ultrasonic assisted decolorization, etc. Among them, the high-temperature stirring physical adsorption method commonly uses white clay with a small amount of activated carbon for decolorization. It has a large amount of decolorizing agent, a long decolorizing time, low utilization of the decolorizing agent, high temperature produces other harmful substances that affect product quality, and excessive use of decolorizing agent causes trace nutrients in oil Many problems such as material loss and poor stability. The chemical decolorization method generally also has problems such as high requirements for reagents, narrow application range, cumbersome removal of impurities after decolorization, and hidden dangers of residual chemical substances. The membrane decolorization method is clean and efficient, but its selectivity is not strong, the equipment cost is high, the regeneration is relatively difficult, and maintenance and maintenance are time-consuming and laborious, which is not conducive to large-scale long-term stable production. The light energy decolorization method has a better effect on specific pigments, but the application range is narrower and the light energy quality requirements are higher. At present, it has not reached the standard for large-scale application. Ultrasound can play the role of decolorization of grease to a certain extent. It can mainly promote the mass transfer rate of the decolorization process and improve the adsorption efficiency of the decolorizing agent. However, its degree of improvement for the decolorizing agent with higher decolorizing efficiency is limited, and the ultrasonic attenuation in large containers is obvious. 1. The local high temperature of the device is likely to have an adverse effect on grease, and the intermittent production has a low utilization rate of ultrasound.

Microalgae have high pigment content, and the crude oil extracted from microalgae usually has a higher red light and appears brownish red. For example, DHA hair oil uses Lovibond colorimetric detection red value up to 15.0 or more. When the physical adsorption method is used to decolorize DHA hair oil, in order to obtain refined oils with lighter color and better quality, it is often adopted to increase the amount of decolorizing agent, extend the time of decolorization, increase the temperature of decolorization, increase the number of decolorization, etc. Traditional means. Although the color index of the final product can be qualified, it will inevitably lead to low product refining yield, low utilization rate of decolorizing agent, excessive loss of beneficial nutrients (microtocopherol, sterol), harmful substances (hydroperoxidation products, trans fatty acids) , Polycyclic aromatic hydrocarbons, glycidyl esters, 3-MCPD, etc.) have problems such as enrichment, which affect the nutritional quality and food safety of oils and fats, which is contrary to the proper processing of edible oils and fats.

Unsaturated fatty acids generally have a quality risk, that is, they are easily oxidized, causing the oil to deteriorate too quickly and produce an unpleasant odor. The generation of unpleasant odors can be basically attributed to the formation of aldehyde ketone quinone oxidation products. Aldehyde quinone compounds can destroy the normal physiological functions of human cells, promote blood pressure increase, reduce the absorption efficiency of fat-soluble vitamins of the human body, and are very easy to cause cancer. The presence of aldehyde quinone compounds in oils has brought great health to human health Impact. The aldehyde ketone quinones in fats and oils can be classified as "volatile" or "non-volatile". Because the primary oxidation product produced by the oxidation of oils and fats is the main source of volatile aldehyde ketone quinone, its content in oils and fats can be expressed in terms of peroxide value, and volatile aldehyde ketone quinones can be obtained through standard refining processes such as deodorization processes well known in the industry Remove. The non-volatile aldehyde ketone quinone has a relatively high boiling point, so it is more difficult to remove in fats and oils, which may cause durability problems. The anisidine value of oils and fats is a standard measure for evaluating the content of oil and fat secondary oxidation products (aldehyde ketone quinone). Highly unsaturated fatty acids are easily oxidized, resulting in higher levels of anisidine in fats than other vegetable fats. For example, before the refining of DHA crude oil, the anisidine value easily rises to more than 15.0, and it basically cannot be reduced in the subsequent refining process. At present, my country does not have clear restrictions on the anisidine value of edible oils and fats. Therefore, the domestically produced DHA and ARA products are mixed with fish and dragon, the overall anisidine value is high, and the product quality stability is not good.

At present, there are usually the following to reduce the value of oil anisidine: chemical elimination method, chemical elimination and physical adsorption combination method, pure chromatography adsorption method. Among them, the chemical elimination method, chemical elimination and physical adsorption combination method all use different chemical reagents to convert the small molecule aldehyde ketone quinone in the oil, and use repeated cleaning or physical adsorption to remove the conversion products; this method is generally more harsh on the reaction conditions To reduce the anisidine value and produce other uncontrollable products, the subsequent treatment is relatively complicated, and there are still large residual hidden dangers, which has a certain impact on product safety. The pure chromatographic chromatography adsorption method has a very high degree of separation of impurities in oils and fats. The commonly used chromatography packings are various types of silica gel, but there are still fillers (silica gel) that are expensive and excessive adsorption performance leads to the loss and operation of trace nutrients in oils and fats. There are many problems such as harsh conditions (high operating pressure) and high equipment cost.

In recent years, some colleagues have proposed the use of room temperature physical adsorption methods to remove oil pigments and reduce anisidine value. For example, using a silica gel with a high separation factor and a decolorant mixture as an adsorbent, and using a solvent elution method to purify the oil; it must be To a certain extent, it solves the problems of large amount of decolorizing agent, long decolorizing time, low utilization rate of decolorizing agent, and other harmful substances produced by high temperature affecting product quality. However, this method has the following shortcomings: the deep red light has a limited ability to remove oil pigments, the use of fillers (such as silica gel) is expensive, the excess adsorption performance leads to the loss of oil and fat micronutrients (the product stability becomes poor), and the adsorption column pressure is high (Equipment cost is higher), the regenerative performance of adsorbent is generally low in reuse rate.

CN101497026A discloses a decolorizer that reduces the anisidine value of soybean oil for injection. The decolorizer has a high decolorization rate, but the ability to reduce the anisidine value using traditional high-temperature adsorption methods is limited, and it is difficult to deal with oils with anisidine value higher than 15.0. At high temperatures, there is still a risk of other harmful substances, and the decolorizer cannot be reused after use.

CN105542951A discloses the use of graphitized carbon as a solid-phase extraction column, which can effectively decolorize microalgal oil at normal temperature, avoiding the risks caused by traditional high-temperature adsorption, but its ability to handle the oil anisidine value is limited.

CN106978254A discloses a bleaching technology that incorporates chemical substances such as glycerol or potassium glycerol, which has a high efficiency of removing red light from oils and fats, but the chemical method requires multiple washings of the product after bleaching, which takes time and effort, and There are still hidden dangers to other aspects of product quality, and the ability to handle the anisidine value of oils and fats is also limited.

CN101879436A discloses a method for decolorizing DHA normal temperature column. It uses activated silica gel, diatomaceous earth, activated carbon and sucrose as a column to fill the column, and uses a solvent to elute at room temperature. This method can effectively reduce oil color and peroxide Value, but the processing raw material is alkaline refining, its color is relatively light, the decolorizing agent does not contain materials that absorb red light efficiently, the pressure is high when processing crude oil, it does not reflect the effect on the anisidine value, and the decolorizing agent is used It cannot be reused later.

CN103908946A discloses a method for preparing a mixed adsorbent, which can prepare a low anisidine value, low absorbance and low 3-MCPD oil for injection, wherein the raw materials used are lower anisidine value (<5.0) and low Absorbent grease (less than 0.1), which has a higher pressure when processing crude oil; the silica gel used is relatively expensive, the amount of adsorbent used is large, and cannot be reused; processing grease requires higher pressure, and the equipment requirements are higher when scaling up mass production ; The oxidation stability of the treated oil is relatively poor; therefore, the cost is higher in the mass production process of edible oil, and the application is more difficult.

Summary of the invention

The present invention aims to provide a new mixed adsorbent and its application and processing method and equipment for polyunsaturated fatty acids, so as to realize the physical reduction of the red light value and anisidine value of polyunsaturated fatty acids under normal temperature conditions, while ensuring the treatment The cost is low and the difficulty of large-scale production and application is small.

Alumina and silica gel are commonly used strong polar adsorption fillers for chromatography purification. Compared with silica gel, alumina is cheap, easy to regenerate, and easy to control activity. However, the separation and purification of fatty acids is not suitable for the use of basic alumina; under neutral or slightly acidic conditions, the use of non-polar solvent elution, the comprehensive adsorption effect of silica gel is stronger than neutral or acidic alumina, so silica gel The removal ability of small molecule aldehyde ketone quinone is slightly stronger than alumina. But at the same time, silica gel has a stronger adsorption and retention effect on other nutrients (such as tocopherol) in the oil and fat will cause the loss of nutrients, and the adsorption performance of neutral or acidic alumina is relatively weak.

Activated clay is the decolorizing agent with the best oil decolorization effect on the market, but its large single batch dosage and relatively large viscosity make it difficult to filter, and the regeneration of clay is also difficult. When using ordinary temperature column to decolorize, using a large amount of white clay will cause the column pressure to be too high and the processing capacity to be low; at the same time, it is difficult to recycle and use the column frequently, which increases the material cost and operating cost. The zeolite molecular sieve used in the present invention is modified with a copper salt to carry a metal center adsorption site. After ultrasonic activation, it can produce strong adsorption and local catalysis for some active pigments and has a very strong processing ability for oil red light. It can reach the equivalent level of activated clay, and after multiple regenerations, the adsorbent still has the same level of treatment capacity for red light. The column pressure is smaller than that of clay, which is an excellent substitute for clay.

After continuous experiments, the inventor of the present invention has surprisingly found that the use of copper salt modified zeolite molecular sieve in combination with neutral and/or acidic alumina, supplemented by ultrasonic activation, can greatly enhance the adsorption of aldehyde ketone quinone and The ability to remove red light (comparable to silica gel), at the same time has the advantages of low price, easy regeneration, small loss of other nutrients, and excellent product stability. Based on this, the present invention has been completed.

Specifically, the present invention provides a mixed adsorbent, wherein the mixed adsorbent contains alumina and a copper salt modified zeolite molecular sieve, and the alumina is neutral alumina and/or acidic alumina.

Preferably, based on the total weight of the copper salt-modified zeolite molecular sieve, the copper salt content in terms of copper oxide is 0.1-8.0 wt%.

Preferably, the copper salt-modified zeolite molecular sieve is prepared according to the following method: the copper-containing compound is attached to the inner and outer surfaces of the porous zeolite molecular sieve, dried at 80 to 120°C, and then baked at 400 to 600°C for 2 to 10 hour.

Preferably, the method of attaching the copper-containing compound to the inner and outer surfaces of the porous zeolite molecular sieve is a dipping method or an ion exchange method.

Preferably, the copper-containing compound is selected from at least one of copper nitrate, copper sulfate, copper acetate and copper acetylacetonate.

Preferably, the porous zeolite molecular sieve is selected from at least one of natural clinoptilolite molecular sieve, activated zeolite molecular sieve, sodium zeolite molecular sieve, high-silicon ZSM molecular sieve and mercerized molecular sieve.

Preferably, the mixed adsorbent further contains at least one of clay, attapulgite, silica and activated carbon.

Preferably, the content of alumina in the mixed adsorbent is 10-40 parts by weight, the content of the copper salt modified zeolite molecular sieve is 2-10 parts by weight, and the contents of clay, attapulgite, silica, and activated carbon are each independent The ground is 0.2 to 5 parts by weight.

Preferably, the content of alumina in the mixed adsorbent is 25 to 35 parts by weight, the content of the copper salt modified zeolite molecular sieve is 3 to 9 parts by weight, and the contents of clay, attapulgite, silica and activated carbon are independent of each other The ground is 0.5 to 3 parts by weight.

Preferably, the particle size of the alumina is 50-1000 mesh, more preferably 70-300 mesh.

Preferably, the particle sizes of the copper salt-modified zeolite molecular sieve, clay, attapulgite, silica, and activated carbon are each independently 40 to 600 mesh, and more preferably each independently are 100 to 300 mesh.

The invention also provides the application of the mixed adsorbent as a decolorizing agent for polyunsaturated fatty acids and an anisidine value reducing agent.

The present invention also provides a method for processing polyunsaturated fatty acids. The polyunsaturated fatty acids have a red light value of 4 or more and anisidine value of 3 or more determined by the Rovibond colorimetric method. The method includes mixing the above The adsorbent is subjected to ultrasonic activation pretreatment, and the resulting active adsorbent is used to decolorize the polyunsaturated fatty acid and reduce the anisidine value.

Preferably, the method for processing polyunsaturated fatty acids includes the following steps:

(1) Ultrasonic activation pretreatment: the above mixed adsorbent is packed into the adsorption column, and the mixed adsorbent in the adsorption column is subjected to activation pretreatment with ultrasound under the solvent infiltration state to obtain an activated adsorption column;

(2) Sample loading and elution: dissolve the polyunsaturated fatty acids in a diluted solvent to prepare a sample loading solution, and then use the sample loading solution to load the active adsorption column under ultrasonic conditions The solvent in the active adsorption column is separated to obtain an effluent. After the sample is loaded, the elution solvent is used to elute the eluent, and the effluent and the eluent are mixed and then concentrated.

Preferably, in step (1), the total ultrasonic power is 20-100 w/L column volume, the ultrasonic frequency is 15-100 kHz, the temperature of the activation pretreatment is 30-60° C. and the time is 20-60 min .

Preferably, in step (1), the total ultrasonic power is 30-60 w/L column volume, the ultrasonic frequency is 20-60 kHz, the temperature of the activation pretreatment is 35-50° C. and the time is 30-40 min .

Preferably, in step (2), the weight ratio of the polyunsaturated fatty acid used in the preparation process of the loading liquid to the dilution solvent is 1: (0.5-3).

Preferably, in step (2), the solvent in the active adsorption column is separated by increasing the pressure in the active adsorption column to 0.02 to 0.2 MPa.

Preferably, in step (2), the total ultrasound power is 15-100 w/L column volume, and the ultrasound frequency is 15-100 kHz.

Preferably, in step (2), during the loading and elution process, the column temperature of the active adsorption column is controlled at 30-60°C.

Preferably, in step (2), the amount of the elution solvent used is 1.2-4.0 times the column volume.

Preferably, in step (2), the dilution solvent is selected from at least one of n-hexane, cyclohexane, isohexane, isopentane, n-pentane and petroleum ether.

Preferably, in step (2), the elution solvent is selected from at least one of n-hexane, n-pentane and petroleum ether.

Preferably, the polyunsaturated fatty acid processing method further includes a step of regenerating the adsorption column after the sample loading and elution steps.

Preferably, the regeneration method includes: washing the adsorption column with a polar solvent under a pressure of 0.03 to 0.2 MPa under ultrasonic conditions.

Preferably, the amount of the polar solvent is 1 to 4 times the column volume.

Preferably, the polar solvent is at least one of acetone, methyl ethyl ketone, tetrahydrofuran and ethyl acetate, or a mixture of at least one of acetone, methyl ethyl ketone, tetrahydrofuran and ethyl acetate and the elution solvent.

Preferably, the ultrasound conditions include a total power of 20-100 w/L column volume and a frequency of 15-100 kHz.

Preferably, the temperature of the column washing is 15-65°C.

In addition, the present invention also provides a processing apparatus for polyunsaturated fatty acids, wherein the processing apparatus includes an adsorption column and a jacket disposed around the adsorption column, and there is a certain gap between the adsorption column and the jacket It is used to set an ultrasonic rod and store an ultrasonic medium. The adsorption medium filled in the adsorption column is the above mixed adsorbent.

Preferably, the ratio of the height of the adsorption medium filled in the adsorption column to the inner diameter of the adsorption column is (4-25):1.

Preferably, the inner diameter of the jacket is 2 to 20 times the outer diameter of the adsorption column.

Preferably, the ultrasonic rods are arranged around the adsorption column, and the number of the ultrasonic rods is 2-6.

Preferably, the ultrasonic medium is selected from at least one of water, ethanol and thermal oil.

The mixed adsorbent provided by the present invention is used to treat polyunsaturated fatty acids, which can effectively reduce the red color of the crude oil under high temperature conditions, and greatly reduce the high boiling aldehyde ketone quinone in the crude oil (represented by anisidine value). Compared with similar technical solutions, the advantages are as follows: (1) It still has strong processing capacity for high red light (Rovibon colorimetric method ≥15.0) and high anisidine value (≥15.0), and it has a wide universality; ( 2) It has good selectivity to pigments and high-boiling aldehyde ketone quinones, and can still retain trace amounts of tocopherols and sterols in some fats and oils to improve the stability of decolorized fats and oils; (3) The process pressure is lower, and the processing efficiency is higher. Large-scale production is only equivalent to low-pressure chromatography, which reduces the requirements for process equipment and saves costs; (4) The mixed adsorbent is cheap, has a long life, and can recover a certain processing capacity after elution regeneration, and can be reused multiple times ; (5) It can realize continuous production and improve production efficiency.

BRIEF DESCRIPTION

The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification, together with the following specific embodiments to explain the present invention, but do not constitute a limitation of the present invention. In the drawings:

1 is a schematic structural diagram of a polyunsaturated fatty acid processing device provided by the present invention;

2 is a graph of the results of accelerated oxidation experiments of Examples 1 to 7 and Comparative Example 4, Comparative Example 6, and Comparative Example 7. FIG.

DESCRIPTION OF REFERENCE NUMERALS

1-adsorption column; 2-jacket; 3-ultrasonic rod; 4-ultrasonic medium; 5-adsorption medium.

detailed description

The present invention will be described in detail below.

The mixed adsorbent provided by the present invention contains alumina and a copper salt modified zeolite molecular sieve, and preferably further contains at least one of clay, attapulgite, silica and activated carbon. The alumina is neutral alumina and/or Or acid alumina. The mixed adsorbent may be used after uniformly mixing the components, or the components may be used in a layered and tiled manner.

The copper salt-modified zeolite molecular sieve uses porous zeolite molecular sieve as a raw material, and is a porous molecular sieve rich in divalent copper obtained after modification. The divalent copper is preferably present in the form of copper oxide. According to a preferred embodiment of the present invention, the copper salt-modified zeolite molecular sieve is prepared according to the following method: the copper-containing compound is attached to the inner and outer surfaces of the porous zeolite molecular sieve, and the molecular sieve is optionally washed with water until colorless, and then It is dried at 80 to 120°C, and then baked at 400 to 600°C for 2 to 10 hours. Wherein, the method of attaching the copper-containing compound to the inner and outer surfaces of the porous zeolite molecular sieve may be a dipping method or an ion exchange method. The copper-containing compound may be organic copper or inorganic copper, and specific examples thereof include, but are not limited to, at least one of copper nitrate, copper sulfate, copper acetate, and copper acetylacetonate. The porous zeolite molecular sieve has an extremely high internal surface area, and specific examples thereof include but are not limited to: at least one of natural clinoptilolite molecular sieve, activated zeolite molecular sieve, sodium zeolite molecular sieve, high-silicon ZSM molecular sieve, and mercerized molecular sieve Species. In addition, based on the total weight of the copper salt-modified zeolite molecular sieve, the content of copper salt in terms of copper oxide is preferably 0.1 to 8.0% by weight.

The mixed adsorbent preferably contains 10 to 40 parts by weight of alumina, 2 to 10 parts by weight of copper salt-modified zeolite molecular sieve, and further contains 0.2 to 5 parts by weight of clay and/or 0.2 to 5 parts by weight of attapulgite. And/or 0.2 to 5 parts by weight of silica, and/or 0.2 to 5 parts by weight of activated carbon. More preferably, the mixed adsorbent contains 10 to 40 parts by weight of alumina, 2 to 10 parts by weight of copper salt modified zeolite molecular sieve, and further contains 0.5 to 5 parts by weight of clay, and/or 0.5 to 5 parts by weight of unevenness Clay soil, and/or 0.2 to 3 parts by weight of silica, and/or 0.2 to 5 parts by weight of activated carbon. More preferably, the mixed adsorbent contains 25 to 35 parts by weight of alumina, 3 to 9 parts by weight of copper salt modified zeolite molecular sieve, and further contains 0.5 to 3 parts by weight of white clay, and/or 0.5 to 3 parts by weight of unevenness Clay soil, and/or 0.5 to 3 parts by weight of silica, and/or 0.5 to 3 parts by weight of activated carbon. Most preferably, the mixed adsorbent preferably contains 25 to 35 parts by weight of alumina, 3 to 9 parts by weight of copper salt modified zeolite molecular sieve, and further contains 1 to 3 parts by weight of white clay, and/or 1 to 3 parts by weight Attapulgite, and/or 1 to 2 parts by weight of silica, and/or 0.5 to 2 parts by weight of activated carbon.

In the present invention, the particle size of each component in the mixed adsorbent is not particularly limited. For example, the particle size of the alumina may be 50-1000 mesh, preferably 70-300 mesh. The particle size of the copper salt-modified zeolite molecular sieve, clay, attapulgite, silica, and activated carbon may each independently be 40 to 600 mesh, preferably each independently be 100 to 300 mesh.

The invention also provides the application of the mixed adsorbent as a decolorizing agent for polyunsaturated fatty acids and an anisidine value reducing agent.

The present invention also provides a method for processing polyunsaturated fatty acids. The polyunsaturated fatty acids have a red light value of 4 or more (preferably 7 to 40) and an anisidine value of 3 or more (preferably 8 to 30), wherein the method includes subjecting the mixed adsorbent to ultrasonic activation pretreatment, and using the obtained active adsorbent to decolor the polyunsaturated fatty acid and reduce the anisidine value.

According to a specific embodiment of the present invention, the method for processing polyunsaturated fatty acids includes the following steps:

(1) Ultrasonic activation pretreatment: the above mixed adsorbent is packed into the adsorption column, and the mixed adsorbent in the adsorption column is subjected to activation pretreatment with ultrasound under the solvent infiltration state to obtain an activated adsorption column;

(2) Sample loading and elution: dissolve the polyunsaturated fatty acids in a diluted solvent to prepare a sample loading solution, and then use the sample loading solution to load the active adsorption column under ultrasonic conditions The solvent in the active adsorption column is separated to obtain an effluent. After the sample is loaded, the elution solvent is used to elute the eluent, and the effluent and the eluent are mixed and then concentrated.

In step (1), the method for loading the mixed adsorbent into the adsorption column may be dry packing or wet packing. When the column is packed by dry method, it is necessary to use a solvent to infiltrate the entire column before performing ultrasonic activation pretreatment; when the column is packed by wet method, the mixed adsorbent itself is already in the state of solvent infiltration, and the ultrasound can be directly carried out after packing Activation pretreatment. The solvent used therein may be, for example, at least one of n-hexane, cyclohexane, isohexane, isopentane, n-pentane, and petroleum ether. In addition, the ratio of the adsorption medium filled in the adsorption column to the inner diameter of the adsorption column may be (4-25):1, preferably (5-10):1.

In step (1), when the mixed adsorbent is infiltrated with a solvent, ultrasound is turned on to perform activation pretreatment on the mixed adsorbent. The total power of the ultrasound is calculated according to the volume of the adsorbent column, preferably 20 to 100 w/L column volume, more preferably 30 to 60 w/L column volume. The ultrasonic frequency is preferably controlled at 15-100 kHz, and more preferably 20-60 kHz. In addition, the temperature of the activation pretreatment is preferably 30 to 60°C, more preferably 35 to 50°C; the time is preferably 20 to 60 min, and more preferably 30 to 40 min.

In step (2), most of the pigments in the polyunsaturated fatty acids, aldehyde ketone quinone, and a small amount of other nutrients will be adsorbed on the active adsorption column after loading, and after elution, a small part of the pigment and aldehyde Ketone quinone and almost all other nutrients will be desorbed from the active adsorption column, while most of the pigment and aldehyde ketone quinone will remain on the active adsorption column.

In step (2), the weight ratio of the polyunsaturated fatty acid used in the preparation process of the loading liquid to the dilution solvent may be 1:((0.5-3). Specific examples of the dilution solvent used here include but are not limited to : At least one of n-hexane, cyclohexane, isohexane, isopentane, n-pentane, and petroleum ether. The method of separating the solvent in the active adsorption column may be standing for a long time to allow the solvent to flow naturally Dry, it can also be (using a metering pump or air pressure method) to increase the pressure in the active adsorption column to 0.02 ~ 0.2MPa, preferably to 0.03 ~ 0.1MPa to accelerate the flow of solvent out of the adsorption column, the latter is preferred to save time The total ultrasonic power is calculated according to the adsorption column volume, preferably 15-100w/L column volume, more preferably 30-60w/L column volume. The ultrasound frequency is preferably controlled at 15-100kHz, more preferably at 20- 60kHz. During loading and elution, the column temperature of the active adsorption column is preferably controlled at 30 to 60°C, more preferably at 40 to 50°C. During the elution, the elution solvent used Specific examples include, but are not limited to: at least one of n-hexane, n-pentane, and petroleum ether. In addition, the amount of the elution solvent used is preferably 1.2 to 4.0 column volumes, and more preferably 1.5 to 2.5 column volumes. The effluent and eluent are mixed and concentrated to remove the organic solvent, and then the target oil is obtained. The method of concentration can be, for example, evaporation and concentration. The eluted solvent can be collected and used for next sample loading. Adsorption.

The method for processing polyunsaturated fatty acids provided by the present invention preferably further includes the step of regenerating the adsorption column after the sample loading and elution steps. According to a specific embodiment of the present invention, the regeneration method includes: washing the adsorption column with a polar solvent under a pressure of 0.03 to 0.2 MPa under ultrasonic conditions. Among them, the amount of the polar solvent is preferably 1 to 4 times the column volume, and more preferably 2 to 3 times the column volume. The temperature of the column washing is preferably controlled at 15 to 65°C, more preferably at 30 to 50°C. The total ultrasonic power is calculated according to the adsorption column volume, preferably 20 to 100 w/L column volume, more preferably 30 to 60 w/L column volume. The ultrasonic frequency is preferably controlled at 15-100 kHz, and more preferably 20-60 kHz. The polar solvent may be at least one of acetone, methyl ethyl ketone, tetrahydrofuran, and ethyl acetate, or a mixture of at least one of acetone, methyl ethyl ketone, tetrahydrofuran, and ethyl acetate, and the elution solvent. Wherein, the total amount of acetone, methyl ethyl ketone, tetrahydrofuran and ethyl acetate in the polar solvent is preferably 50-100 wt%, more preferably 60-90 wt%.

In addition, as shown in FIG. 1, the processing equipment for polyunsaturated fatty acids provided by the present invention includes an adsorption column 1 and a jacket 2 disposed on the periphery of the adsorption column 1. There is a certain distance between the adsorption column 1 and the jacket 2 The gap is used for setting the ultrasonic rod 3 and storing the ultrasonic medium 4, and the adsorption medium 5 filled in the adsorption column 1 is the above mixed adsorbent.

The ratio of the height of the adsorption medium filled in the adsorption column 1 to the inner diameter of the adsorption column is preferably (4-25):1, and more preferably (5-10):1. The inner diameter of the jacket is preferably 2 to 20 times the outer diameter of the adsorption column, and more preferably 10 to 18 times. The ultrasonic rods are arranged around the adsorption column, and the number of the ultrasonic rods is preferably 2-6. When the number of the ultrasonic rods is more than 3, multiple ultrasonic rods are preferably distributed at equal intervals around the adsorption column. The ultrasonic medium may be, for example, at least one selected from water, ethanol, and thermal oil, preferably water.

The present invention will be described in detail below through examples.

In the following examples and comparative examples, the equipment and materials used are shown in Tables 1 to 3 below:

Table 1 Instruments and specifications manufacturers

project	Model/Specification	factory
Lovibond colorimeter	WSL-2	Hangzhou Raccoon Instrument Technology Co., Ltd.
Rotary evaporator	RE-52AA	Shanghai Jinghong Experimental Equipment Co., Ltd.
Type vacuum constant temperature drying oven	DZF-6505	Shanghai Anting Scientific Instrument Factory

Table 2 Absorbent specifications and manufacturers

name	specification	factory
Alumina	80～120 mesh	Qingdao Weina Chemical Co., Ltd.
White clay	100～200 mesh	Huangshan Baiyue Active Clay Co., Ltd.
Attapulgite	200～400 mesh	Yunda Mineral Products Co., Ltd.
Silica	100～200 mesh	Tianjin Longhua Chengxin Powder Technology Co., Ltd.
Activated carbon	60～80 mesh	Shanghai Heavy Machinery Import & Export Chemical Co., Ltd.
diatomite	100～300 mesh	Linjiang Shengmai Diatomite Functional Material Co., Ltd.
Magnesium silicate	100～200 mesh	Magnesium silicate Guangzhou Yifeng Chemical Technology Co., Ltd.
Zeolite molecular sieve	100～250 mesh	Ningbo Jiahe New Material Technology Co., Ltd.
Silica gel	200～300 mesh coarse hole	Qingdao Weina Chemical Co., Ltd.
Copper nitrate	Chemically pure	Langfang Pengcai Fine Chemical Co., Ltd.

Table 3 Parameters of adsorbed raw oil

project	Peroxide value meq/kg	Anisidine value	Luo Weipeng red light
DHA crude oil	3.8	16.3	15.1
ARA hair oil	2.7	18.6	17.2

Preparation Example 1

This preparation example is used to explain the preparation method of the copper salt modified zeolite molecular sieve provided by the present invention.

The natural clinoptilolite molecular sieve was immersed in an aqueous solution of copper nitrate with a concentration of 0.10 mol/L, and the molecular sieve was washed with deionized water to be colorless, then dried at 80°C, and then baked at 400°C for 10 hours to obtain copper Salt modified zeolite molecular sieve, referred to as S1. Wherein, based on the total weight of the copper salt-modified zeolite molecular sieve, the copper salt content in terms of copper oxide is 0.26 wt%.

Preparation Example 2

This preparation example is used to explain the preparation method of the copper salt modified zeolite molecular sieve provided by the present invention.

Immerse the mercerized molecular sieve in an aqueous solution of copper nitrate with a concentration of 0.20 mol/L, rinse the molecular sieve with deionized water until it is colorless, then dry at 120°C, and then roast at 600°C for 2 hours to obtain a copper salt Zeolite molecular sieve, which is referred to as S2. Based on the total weight of the copper salt-modified zeolite molecular sieve, the copper salt content in terms of copper oxide is 2.13 wt%.

Preparation Example 3

This preparation example is used to explain the preparation method of the copper salt modified zeolite molecular sieve provided by the present invention.

Sodium zeolite molecular sieve was immersed in 0.12mol/L copper nitrate aqueous solution, and then the molecular sieve was washed with deionized water to be colorless, then dried at 100 ℃, and then baked at 500 ℃ for 6 hours to obtain copper Salt modified zeolite molecular sieve, referred to as S3. Wherein, based on the total weight of the copper salt-modified zeolite molecular sieve, the copper salt content in terms of copper oxide is 1.34 wt%.

Examples 1 to 7 and Comparative Examples 1 to 5

80-120 mesh acidic alumina 27.0-33.0g, copper salt modified zeolite molecular sieve 4.0-9.0g, activated clay 0.0-1.0g, attapulgite 0.0-2.0g, silica 0.0-1.0g, activated carbon 0 ~2.0g, weighed according to weight ratio, packed in glass chromatography column by wet method, the specific packing weight is shown in Table 4. After that, ultrasonic activation pretreatment is used to obtain active adsorption. Mix 100.0g of DHA/ARA hair oil with 200ml of dilute solvent to obtain the sample solution. After stirring, perform the sample application under ultrasonic conditions and separate the solvent in the active adsorption column to obtain the effluent. The eluent was eluted. Collect all the eluent, mix the effluent and the eluent and concentrate it under vacuum -0.1MPa at 50°C. Cool down to obtain a light-colored low-anisidine decolorized oil. The decolorized oil was tested for Rovibond color and anisidine value, and the results are shown in Table 4. After elution is completed, 200ml of polar solution is added to the adsorption column to maintain the column temperature and ultrasonic intensity, and the column is washed under a pressure of 0.03-0.05MPa. The ultrasound conditions and column temperature used throughout the process are the same, as shown in Table 4. After washing the column, add 100ml of the elution solvent to equilibrate the column. Using the same crude oil raw material sample loading solution and the same adsorption column, the adsorption and decolorization were repeated 5 times after washing the column, and the effect of repeated use on the decolorization of the adsorption column and the efficiency of reducing the anisidine value was investigated. The results are shown in Table 4.

Comparative Example 6

The above DHA crude oil is treated according to the method disclosed in CN101879436A, the specific treatment method is as follows:

Immerse 200g of silica gel in 500ml of methanol for 1 hour, and then collect methanol by suction filtration. Rinse the silica gel with 3 times the volume of methanol in deionized water. After filtering off the water, heat it at 110°C for more than 12 hours to obtain activated silica gel. Stir diatomite and activated carbon at a mass ratio of 1:1 to obtain a mixture of diatomite and activated carbon, which is called mixture 1. Mix the diatomaceous earth and sucrose at a mass ratio of 1:2 to obtain a mixture of diatomaceous earth and sucrose, which is called mixture 2. Soak mixture 1 and mixture 2 in n-hexane, and wash with n-hexane repeatedly until the eluent has no peroxide value. 20g activated silica gel, 5g mixture 1, 5g mixture 2, and 20g activated silica gel were packed in a wet order from the bottom to the top of the column in the above order. The column was washed with a pressure of 0.05MPa to compact the packing to obtain a decolorized column.

100.0g DHA crude oil was dissolved in n-hexane at a 1:1 volume ratio, injected into the above decolorizing column and pressurized with nitrogen to 0.1MPa for elution. Add n-hexane to continue elution until the eluent had no oil trace on the filter paper, collect elution liquid. Afterwards, the eluent was concentrated at 45° C. under vacuum-0.1 MPa to recover n-hexane to obtain light-colored grease. The decolorized oil was tested for Rovibond color and anisidine value, and the results are shown in Table 4. After elution is completed, 200 ml of polar solvent is added to the adsorption column, the column temperature is maintained at 50°C, and the column washing pressure is maintained at 0.03 to 0.05 MPa. After washing the column, add 100ml of n-hexane to the column to equilibrate the column. Using the same crude oil raw material sample loading solution and the same adsorption column, the adsorption and decolorization were repeated 5 times after washing the column, and the effect of repeated use on the decolorization of the adsorption column and the efficiency of reducing the anisidine value was investigated. The results are shown in Table 4.

Comparative Example 7

The above DHA crude oil is treated according to the method disclosed in CN103908946A, the specific treatment method is as follows:

Mix 12.0 g of silica gel (200-300 mesh), 12.0 g of activated clay, 12.0 g of activated carbon, and 12.0 g of magnesium silicate, add 100 ml of petroleum ether, and stir evenly. Wet packing column to ensure no bubbles in the adsorption column. The column temperature was maintained at 40°C, the ultrasonic activated adsorption column was turned on, and ultrasonic activated at 30 kHz for 30 min. 100.0g DHA crude oil and 200ml petroleum ether are formulated into a uniform sample loading solution, the loading pressure is maintained at 0.03 ~ 0.05MPa, the column temperature is maintained at 40 ℃, and the ultrasonic intensity is maintained; after the sample is completed, 100ml petroleum ether is added to the column to elute, Collect all elution solutions. Afterwards, the eluted solution was concentrated under vacuum-0.1 MPa at 50°C, and the temperature was lowered to obtain a light-colored decolorized oil with low anisidine value. The decolorized oil was tested for Rovibond color and anisidine value, and the results are shown in Table 4. After elution is completed, 200 ml of polar solvent is added to the adsorption column, the column temperature is maintained at 50°C, the ultrasonic intensity is maintained, and the column washing pressure is maintained at 0.03 to 0.05 MPa. After washing the column, add 100ml of petroleum ether to the column to balance the column. Using the same crude oil raw material sample loading solution and the same adsorption column, the adsorption and decolorization were repeated 5 times after washing the column, and the effect of repeated use on the decolorization of the adsorption column and the efficiency of reducing the anisidine value was investigated. The results are shown in Table 4.

50g of the first processed grease in Examples 1-7, Comparative Example 4, Comparative Example 6, and Comparative Example 7 was used for accelerated oxidation experiments. Specifically, the above grease was placed in a constant temperature drying cabinet at 62°C, and the grease was regularly detected The peroxide value (PV), anisidine value (p-AV), according to the total oxidation value formula (TOTOX value) = 2PV + p-AV to calculate the total oxidation value of oil, according to the change trend to measure the oxidation stability of oil, total oxidation The higher the value, the worse the stability. The results are shown in Figure 2.

It can be seen from the data in Table 4 and FIG. 2 that the oil and fat treatment method provided by the present invention can reduce the DHA/ARA crude oil Luoweipeng red light with red light and anisidine value of 15.0 or more to less than 0.5, and the anisidine value to within 3.0 After 5 times of repeated use, the mixed adsorbent still has high adsorption activity. The column pressure during adsorption and elution is only at the level of 0.03～0.05MPa. When the column is enlarged to the treatment capacity of 500L/h according to the same aspect ratio, the theoretical column pressure does not exceed 1.0MPa, and the general low-pressure chromatography equipment can meet the production requirements. . Adopting the processing methods of Examples 1-7, the adsorption column pressure is better than that of the comparative example using a large amount of silica gel and clay. The comprehensive performance of the three indicators of the treatment of oils in Examples 1-7 is significantly better than the three indicators of anisidine value, red light and stability. Comparative examples 1-7. The change trend of the total oxidation value of the treated oil of Comparative Example 4 was significantly more dramatic, and the oxidation stability after 24 hours was significantly worse than that of Example 1, which was due to the excessive removal of micronutrients (such as tocopherol) in the oil and fat using silicone gel, resulting in the oil Relatively poor stability during long-term storage. It can be seen from the comparison of the test results of Example 1, Comparative Example 1 and Comparative Example 2 that the combination of alumina and copper salt modified zeolite molecular sieve can play a role in anti-red light and reduce the anisidine value. Less synergies. It can be seen from the comparison of the test results of Example 2 and Comparative Example 3 that ultrasound assistance is very important. Through the above test results, it is proved that the combination of alumina+copper salt modified molecular sieve+ultrasound assisted in the removal of red light from oil and grease and the reduction of anisidine value, product stability, adsorption column pressure and the reuse of adsorbent Sex.

The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical idea of the present invention, various simple modifications can be made to the technical solution of the present invention. These simple modifications All belong to the protection scope of the present invention.

In addition, it should be noted that the specific technical features described in the above specific embodiments can be combined in any suitable manner without contradictions. In order to avoid unnecessary repetitions, the present invention will not describe various possible combinations.

In addition, various combinations of various embodiments of the present invention can also be arbitrarily combined, as long as it does not violate the idea of the present invention, it should also be regarded as the content disclosed by the present invention.

Claims (10)

1. A mixed adsorbent, characterized in that the mixed adsorbent contains alumina and copper salt modified zeolite molecular sieve, and the alumina is neutral alumina and/or acidic alumina.
2. The mixed adsorbent according to claim 1, characterized in that, based on the total weight of the copper salt-modified zeolite molecular sieve, the copper salt content in terms of copper oxide is 0.1 to 8.0 wt%;

   Preferably, the copper salt-modified zeolite molecular sieve is prepared according to the following method: the copper-containing compound is attached to the inner and outer surfaces of the porous zeolite molecular sieve, dried at 80 to 120°C, and then baked at 400 to 600°C for 2 to 10 hour;

   Preferably, the method of attaching the copper-containing compound to the inner and outer surfaces of the porous zeolite molecular sieve is a dipping method or an ion exchange method;

   Preferably, the copper-containing compound is selected from at least one of copper nitrate, copper sulfate, copper acetate and copper acetylacetonate;

   The porous zeolite molecular sieve is selected from at least one of natural clinoptilolite molecular sieve, activated zeolite molecular sieve, sodium zeolite molecular sieve, high-silicon ZSM molecular sieve and mercerized molecular sieve.
3. The mixed adsorbent according to claim 1 or 2, wherein the mixed adsorbent further contains at least one of clay, attapulgite, silica, and activated carbon;

   Preferably, the content of alumina in the mixed adsorbent is 10-40 parts by weight, the content of the copper salt modified zeolite molecular sieve is 2-10 parts by weight, and the contents of clay, attapulgite, silica, and activated carbon are each independent Ground is 0.2 ~ 5 parts by weight;

   Preferably, the content of alumina in the mixed adsorbent is 25 to 35 parts by weight, the content of the copper salt modified zeolite molecular sieve is 3 to 9 parts by weight, and the contents of clay, attapulgite, silica and activated carbon are independent of each other Ground is 0.5-3 parts by weight;

   Preferably, the particle size of the alumina is 50-1000 mesh, more preferably 70-300 mesh; the particle size of the copper salt modified zeolite molecular sieve, white clay, attapulgite, silica and activated carbon is independently It is 40 to 600 mesh, and more preferably each is independently 100 to 300 mesh.
4. Use of the mixed adsorbent according to any one of claims 1 to 3 as a decolorizing agent for polyunsaturated fatty acids and an anisidine value reducing agent.
5. A method for processing polyunsaturated fatty acids, the polyunsaturated fatty acids having a red light value of 4 or more and anisidine value of 3 or more determined by the Rovibond colorimetric method, characterized in that the method includes applying claims 1-3 The mixed adsorbent according to any one of the items is subjected to ultrasonic activation pretreatment, and the obtained active adsorbent is used to decolor the polyunsaturated fatty acid and reduce the anisidine value.
6. The processing method according to claim 5, characterized in that the method comprises the following steps:

   (1) Ultrasonic activation pretreatment: the mixed adsorbent according to any one of claims 1-3 is packed into an adsorption column, and the mixed adsorbent in the adsorption column is subjected to ultrasound in a state of solvent infiltration Activation pretreatment to obtain active adsorption column;

   (2) Sample loading and elution: dissolve the polyunsaturated fatty acids in a diluted solvent to prepare a sample loading solution, and then use the sample loading solution to load the active adsorption column under ultrasonic conditions The solvent in the active adsorption column is separated to obtain an effluent. After the sample is loaded, the elution solvent is used to elute the eluent, and the effluent and the eluent are mixed and then concentrated.
7. The processing method according to claim 6, characterized in that

   In step (1), the total ultrasonic power is 20-100w/L column volume, the ultrasonic frequency is 15-100kHz, the temperature of the activation pretreatment is 30-60°C and the time is 20-60min; preferably , The total ultrasound power is 30-60w/L column volume, the ultrasound frequency is 20-60kHz, the temperature of the activation pretreatment is 35-50°C and the time is 30-40min;

   In step (2), preferably, the weight ratio of the polyunsaturated fatty acid used in the preparation of the loading solution to the dilution solvent is 1: (0.5-3); preferably, the solvent in the active adsorption column The separation method is to increase the pressure in the active adsorption column to 0.02 to 0.2 MPa; preferably, the total ultrasonic power is 15 to 100 w/L column volume, and the ultrasonic frequency is 15 to 100 kHz; preferably, at During sample loading and elution, the column temperature of the active adsorption column is controlled at 30-60°C; preferably, the amount of the elution solvent used is 1.2-4.0 times the column volume; preferably, the dilution solvent At least one selected from n-hexane, cyclohexane, isohexane, isopentane, n-pentane, and petroleum ether; preferably, the elution solvent is selected from at least one of n-hexane, n-pentane, and petroleum ether One kind.
8. The processing method according to claim 6, wherein the method further comprises the step of regenerating the adsorption column after the sample loading and elution steps;

   Preferably, the regeneration method includes: washing the adsorption column with a polar solvent under a pressure of 0.03 to 0.2 MPa under ultrasonic conditions;

   Preferably, the amount of the polar solvent is 1 to 4 times the column volume;

   Preferably, the polar solvent is at least one of acetone, methyl ethyl ketone, tetrahydrofuran and ethyl acetate, or a mixture of at least one of acetone, methyl ethyl ketone, tetrahydrofuran and ethyl acetate and the elution solvent;

   Preferably, the total amount of acetone, methyl ethyl ketone, tetrahydrofuran and ethyl acetate in the polar solvent is 50-100 wt%;

   Preferably, the ultrasound conditions include a total power of 20-100w/L column volume and a frequency of 15-100kHz;

   Preferably, the temperature of the column washing is 15-65°C.
9. A processing device for polyunsaturated fatty acids, characterized in that the processing device includes an adsorption column and a jacket disposed around the adsorption column, and there is a certain gap between the adsorption column and the jacket for setting an ultrasonic rod An ultrasonic medium is also stored, and the adsorption medium filled in the adsorption column is the mixed adsorbent according to any one of claims 1-3.
10. The processing device according to claim 9, wherein the ratio of the height of the adsorption medium filled in the adsorption column to the inner diameter of the adsorption column is (4-25): 1; preferably, the inner diameter of the jacket is 2 to 20 times the outer diameter of the adsorption column; preferably, the ultrasonic rods are arranged around the adsorption column, the number of the ultrasonic rods is 2 to 6; preferably, the ultrasonic medium is selected from water, ethanol and heat conduction At least one of the oils.

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