Reaction device and method for preparing medium-chain and long-chain fatty acid edible oil by countercurrent feeding enzyme method

Abstract

The invention relates to the technical field of synthesis of medium-chain and long-chain fatty acid edible oil, in particular to a reaction device and method for preparing medium-chain and long-chain fatty acid edible oil by a countercurrent feeding enzyme method. A conventional enzyme decomposition method for preparing medium-chain and long-chain fatty acid edible oil generally adopts a reaction kettle with a stirring paddle for transesterification, and enzyme particles are easy to crush in the mode; the problems can be well solved by adopting the production device for filling the enzyme column in the fixed bed reactor, but the one-way downstream feeding mode enables the immobilized lipase enzyme column in the fixed bed reactor to be subjected to larger bed pressure, enzyme particles are easy to damage, and the transesterification efficiency and the product quality are seriously influenced. In order to solve the problems, the invention provides the method for preparing the medium-chain and long-chain fatty acid edible oil by the countercurrent feeding enzyme method, the reaction raw materials are pumped into the fixed bed reactor by adopting a countercurrent feeding mode, the probability that enzyme particles are inactivated in the reaction process is greatly reduced, and the reaction efficiency and the product quality of the transesterification reaction are remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of preparing medium-chain fatty acids by enzymatic method, and in particular to a reaction device and a method for preparing medium-chain fatty acid edible oil by enzymatic method with countercurrent feeding. Background Art

[0002] Enzymatic decomposition of triglycerides to prepare fatty acids is a relatively mature technology. Triglycerides are gradually hydrolyzed under the action of lipase to first generate diglycerides, which are further hydrolyzed to generate monoacylglycerols, and finally decomposed into glycerol and fatty acids. Enzymatic decomposition has the advantages of mild reaction conditions, easy control, good selectivity, and low environmental pollution. It is widely used in the fields of oil and fat industry, food industry, and biodiesel. By optimizing the selection of enzymes, reaction conditions, and separation and purification steps, the efficiency and product purity of enzymatic decomposition of triglycerides can be significantly improved. In addition, with the continuous development of biotechnology, new enzyme types and enzyme engineering technologies continue to emerge, providing more possibilities and room for improvement for enzymatic decomposition of triglycerides.

[0003] Conventional enzymatic decomposition methods for preparing medium- and long-chain fatty acid edible oils generally use a reactor with a stirring paddle for ester exchange reaction, which can easily cause the enzyme particles to break. The use of a production device that fills an enzyme column in a fixed bed reactor can solve the above problem well. However, in the case of large amounts of industrial raw materials, if only a one-way cocurrent feeding method is used to pump the reaction raw materials into the fixed bed reactor for ester exchange reaction, the bed pressure of the immobilized lipase catalyst filling layer arranged in the fixed bed reactor is relatively large, and the enzyme particles are easily damaged, which seriously affects the continuity of the ester exchange reaction process as well as the production efficiency and quality of the product. Summary of the invention

[0004] The problems existing in the prior art are: when the amount of raw materials used in industrial production is large, the conventional enzymatic decomposition of fatty acid triglycerides to prepare fatty acids generally uses a reactor with a stirring paddle to carry out ester exchange reaction, which easily causes the enzyme particles to break; the production device using an enzyme column filled in a fixed bed reactor can solve the above problems well. If only a one-way downstream feeding method is used to pump the reaction raw materials into the fixed bed reactor, the bed pressure of the immobilized lipase catalyst filling layer arranged in the fixed bed reactor is relatively large, and the enzyme particles are easily damaged, which seriously affects the continuity of the ester exchange reaction process and the production efficiency and quality of the product. In view of the above technical problems, the present invention provides a reaction device for preparing medium- and long-chain fatty acid edible oil by a countercurrent feeding enzymatic method, which includes a raw material mixing tank, a pretreatment device, a fixed bed reactor, a post-treatment device and a storage tank connected in sequence;

[0005] The raw material mixing tank is equipped with a heating and stirring device, which can heat, melt and evenly mix the reaction raw materials in the raw material mixing tank;

[0006] The pre-processor is filled with an adsorbent for removing free fatty acids and peroxides from the reaction raw materials;

[0007] The catalyst filled in the fixed bed reactor is immobilized lipase;

[0008] Refining and purification are carried out in the post-processor, specifically, the reaction product is decolorized, deacidified and deodorized by using a nitrogen stripping process;

[0009] The pretreatment device is connected to the fixed bed reactor through a pipeline, and the pipeline includes a main pipeline, a side branch pipeline 1 and a side branch pipeline 2. The main pipeline is connected to the side branch pipeline 1 and the side branch pipeline 2 through a tee and are interconnected. The side branch pipeline 1 and the side branch pipeline 2 are each provided with a flow valve, which are a first flow valve and a second flow valve respectively. The main pipeline is provided with a first screw pump. The side branch pipeline 1 is connected to a first feed port on the fixed bed reactor, and the side branch pipeline 2 is interconnected with a second feed port at the bottom of the fixed bed reactor.

[0010] Preferably, the auxiliary branch pipeline 1 and the auxiliary branch pipeline 2 are each provided with a pressure gauge, namely a first pressure gauge and a second pressure gauge, for real-time monitoring of the fluid pressure in the pipeline.

[0011] Preferably, an air inlet and an exhaust valve are provided at the top of the fixed bed reactor, the air inlet is interconnected with the gas blowing device through a flow valve control, the middle and bottom of the fixed bed reactor are respectively provided with a first discharge port and a second discharge port, the first discharge port is interconnected with the third feed port in the middle of the post-processor through a first branch, the second discharge port is interconnected with the waste tank through a second branch, and the first branch and the second branch are interconnected through a third branch;

[0012] Three valves are installed on the first branch, namely the first valve, the second valve and the third valve. The first valve is adjacent to the first discharge port, the second valve is adjacent to the left side of the connection between the third branch and the first branch, and the third valve is adjacent to the connection between the first branch and the post-processor.

[0013] The second branch is provided with two valves, namely a fourth valve and a fifth valve, the fourth valve being located immediately below the fourth discharge port, and the fifth valve being located immediately to the right of the connection port between the third branch and the second branch;

[0014] The third branch is provided with two valves, namely a sixth valve and a seventh valve, the sixth valve is adjacent to the connection port between the third branch and the second branch, and the seventh valve is adjacent to the connection port between the first branch and the third branch;

[0015] A second screw pump is arranged between the first valve and the second valve on the first branch, and a third screw pump is arranged on the left side of the connection port between the second branch and the third branch on the second branch near the second discharge port.

[0016] Preferably, the immobilized lipase in the fixed bed reactor is filled in intervals along the vertical direction in the fixed bed reactor to form enzyme columns, and adjacent enzyme columns are isolated by horizontally arranged microporous partitions, and the microporous partitions do not allow the immobilized lipase to pass through. The immobilized lipase enzyme columns are separated by microporous partitions to form a multi-stage reaction system, which can reduce the occurrence of back mixing, bias flow, and hook flow, and is convenient for improving the reaction conversion rate, improving the reaction efficiency, and extending the catalyst life.

[0017] Preferably, there are at least three enzyme columns arranged along the vertical direction of the fixed bed reactor.

[0018] Preferably, the thickness of the microporous separator is 2-6 mm, and the pore density is 200-600 pores / cm 2 The pore size is 10-50 μm. A temperature sensor is fixedly arranged on the microporous partition plate to monitor and adjust the transesterification reaction temperature in real time.

[0019] Preferably, the adsorbent in the preprocessor is an activated carbon particle layer and a silica particle layer alternately filled along the vertical direction of the preprocessor, the height of a single activated carbon particle layer is 1-1.5m, the height of a single silica particle layer is 1-1.5m, the average particle size of the activated carbon is 1-4mm, the average particle size of the silica is 0.5-2mm, and the number of activated carbon particle layers is at least two.

[0020] Preferably, the immobilized lipase includes Lipozyme 435, Lipozyme FLex, Lipozyme TLIM, Lipozyme RM. Preferably, the fixed bed reactor includes an inner tube and an outer tube, the outer tube is sleeved on the outside of the inner tube, an annular cavity is formed circumferentially between the outer tube and the inner tube, the upper and lower parts of the annular cavity are respectively provided with a medium outlet and a medium inlet, the top of the inner tube is interconnected with the first feed port, the air inlet and the exhaust valve, and the bottom of the inner tube is provided with a first feed port and a second discharge port. Liquid or steam medium can enter the annular cavity from the medium inlet, and then flow out of the annular cavity through the medium outlet. Continuously introducing a medium with a certain temperature into the annular cavity can achieve the heat preservation effect of the inner tube.

[0021] A method for preparing medium- and long-chain fatty acids by a countercurrent feeding enzyme method, which uses the above-mentioned reaction device, and the preparation method specifically comprises the following steps:

[0022] (1) Adding the reaction raw materials into a raw material mixing tank, heating, melting, stirring and mixing them uniformly, then transferring the liquid material in the raw material mixing tank to a pretreatment device for pretreatment to remove free fatty acids and peroxides in the liquid material, and the liquid material treated by the pretreatment device is divided into two streams and enters the inner tube of the fixed bed reactor from the first feed port and the second feed port on the fixed bed reactor respectively to carry out ester exchange reaction. After the ester exchange reaction is completed, all valves on the first branch are opened to allow part of the reaction product in the fixed bed reactor to be pumped into the post-processor, and then the first valve and the second valve on the first branch are closed, and then the fourth valve on the second branch and all valves on the third branch are opened to allow the reaction product remaining at the bottom of the fixed bed reactor to be pumped into the post-processor, and then the third valve switch on the first branch is closed. The reaction product in the post-processor is decolorized, deacidified and deodorized by a nitrogen stripping process, and then transferred to a storage tank;

[0023] (2) After all the reaction products in the post-processor in step (1) enter the storage tank, open the fifth valve switch on the second branch, close all the valve switches on the third branch, close all the valve switches on the first branch, use a gas blowing device to blow nitrogen or inert gas into the fixed bed reactor, blow the grease impurities remaining in the pores of the enzyme column in the fixed bed reactor into the waste tank, and after the blowing is completed, close all the valves on the second branch;

[0024] (3) Then, the reaction raw materials are replaced and steps (1)-(2) are repeated to obtain different types of medium- and long-chain fatty acids.

[0025] Preferably, the reaction raw materials include medium-chain fatty acid triglycerides and long-chain fatty acid triglycerides, wherein the medium-chain fatty acid triglycerides include one or a combination of two or more of palm oil, coconut oil, and industrial food-grade caprylic acid triglycerides, and the long-chain fatty acid triglycerides include one or a combination of two or more of soybean oil, sunflower oil, corn oil, peanut oil, rapeseed oil, olive oil, and linseed oil.

[0026] The present invention has the following beneficial effects:

[0027] (1) The present invention adopts a countercurrent feeding method to significantly reduce the bed pressure of the enzyme column in the fixed bed reactor during the ester exchange reaction, greatly reducing the probability of damage and inactivation of enzyme particles during the ester exchange reaction, which is conducive to further improving the reaction efficiency and product quality;

[0028] (2) The present invention is provided with a gas blowing device at the top of the fixed bed reactor. After a round of production is completed or when other types of fatty acid edible oils need to be produced, the impurities such as grease remaining between the pores of the immobilized lipase column in the fixed bed reactor are blown into a waste tank by the gas blowing device, and then a new round of production is carried out, thereby ensuring the quality of subsequent products, significantly saving production costs, and being able to achieve the effect of continuously producing different types of fatty acid edible oils with a set of reaction devices, and having good application prospects;

[0029] (3) The present invention uses a packed bed reactor to produce medium- and long-chain fatty acid edible oil, thereby avoiding the destruction of the catalyst lipase particles by the traditional mechanical stirring method. By adjusting the countercurrent flow rate of the reaction raw materials, the degree of the ester exchange reaction can be more effectively controlled, the replacement rate of the enzyme column is reduced, and the production cost is significantly saved. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 : Schematic diagram of the structure of the one-way co-current feeding method of the transesterification reaction.

[0031] Figure 2 : Schematic diagram of the structure of the countercurrent feeding method of the ester exchange reaction.

[0032] Figure 3 : A schematic structural diagram of a reaction device for preparing medium- and long-chain fatty acid edible oil by a countercurrent feeding enzyme method provided by the present invention.

[0033] Figure 4 : Schematic diagram of the structure of the reactor with a stirring paddle used in Comparative Example 2.

[0034] In the figure: 1. raw material mixing tank, 2. stirring device, 3. pre-processor, 4. first screw pump, 5. fixed bed reactor, 6. third screw pump, 7. second screw pump, 8. waste tank, 9. post-processor, 10. storage tank, 11. heating sleeve, 12. first flow valve, 13. second flow valve, 14. first pressure gauge, 15. second pressure gauge, 16. first feed port, 17. second feed port, 18. air inlet, 19. exhaust valve, 20. first discharge port, 21. second discharge port, 22. inner tube, 23. annular cavity, 24. microporous partition, 25. temperature sensor, 26. medium inlet, 27. medium outlet, 28. first valve, 29. second valve, 30. third valve, 31. fourth valve, 32. fifth valve, 33. sixth valve, 34. seventh valve. DETAILED DESCRIPTION

[0035] The present invention is described in detail below with reference to the examples. However, it should be understood that the following examples are only illustrative of the embodiments of the present invention, and are not intended to limit the scope of the present invention.

[0036] The enzyme column formed by the accumulation of immobilized lipase particles can be regarded as a particle bed. The density of the bed, i.e., the porosity of the bed, is calculated by the following formula:

[0037]

[0038] Among them, V 床 =πr 2 H;

[0039] Where, ε-bed porosity; V 床 -Bed volume, m 3 ; V 颗 - Particle volume m 3 ; r-radius of the inner tube of the reaction column, m; H-height of the enzyme column, m; m-total mass of the immobilized lipase particles filled, kg; ρ-real density of the immobilized lipase particles, kg / m 3 ;

[0040] The influence of the shape, size and bed porosity of the immobilized lipase particles on the flow of the raw materials can be expressed by the specific resistance R, which is the resistance generated by the unit thickness of the enzyme column. It is numerically equal to the pressure drop generated when a liquid with a viscosity of 1 Pa·s flows through a bed with a thickness of 1 m at an average flow rate of 1 m / s. It can be calculated by the following formula:

[0041]

[0042] in,

[0043] Where, R-specific resistance, 1 / m 2 ; a-specific surface area of ​​immobilized lipase particles, m 2 / m 3 ; d-immobilized lipase particle diameter, m;

[0044] Furthermore, the mathematical model of the pressure drop of fluid through the fixed bed is:

[0045]

[0046] in,

[0047] In the formula, ΔP f - bed pressure drop, pa; C-model parameter, determined by experiment; L-bed height, m; u 1 -actual flow rate of the fluid in the bed, m / s; u-empty bed velocity calculated based on the entire bed cross section, m / s; μ-fluid viscosity, Pa·s;

[0048] Furthermore, the fluid flow rate of this production process is low, and the Reynolds number of the bed is b<2 in laminar flow, the Conzeny model parameters (where K = 5 is the Conzeny constant, ) can be well matched and calculated using the Conzeny equation:

[0049]

[0050] Example 1

[0051] The comparison of the pressures borne by the immobilized lipase column in the fixed bed reactor under the two feeding modes of unidirectional cocurrent and countercurrent is as follows:

[0052] Taking the size of a common fixed bed reactor (fixed bed reactor) in industry as an example, the pressure on the enzyme column under the cocurrent and countercurrent feeding methods is calculated respectively. The average density of the crude oil mixture under different ratios is measured experimentally. 液 About 918.55Kg / m 3 The average viscosity μ is about 47.7 mpa·s, and the feed flow rate u is 8.55×10 -6 m / s, the diameter of the immobilized lipase particles d is 0.05 cm, and the density of the immobilized lipase particles ρ 颗 The design column height is 10m, the reaction column diameter is 2m, and the fixed bed reactor has a filling enzyme column height L of 8m. It needs to be filled with approximately 6936.64kg of enzyme, and the pump pressure is about 0.35Pa.

[0053] Therefore, preliminary calculations show that the specific surface area a of the immobilized lipase particles is 12000 m 2 / m 3 , the bed porosity ε is 0.31, and the bed specific resistance R is 1.15×10 10 .

[0054] The feed is fed in a unidirectional co-current manner, that is, only from the feed port at the top of the fixed bed reactor. Calculate the pressure on the immobilized lipase column in the fixed bed reactor:

[0055] In the unidirectional downstream feeding mode, the pressure on the enzyme column bed is P 顺 The one-way downstream feeding method is as shown in the attached manual. Figure 1 The calculation formula is as follows:

[0056] P 顺 =ρgh+ΔP f +P 0 ;

[0057] P 0 Take 0.18Pa;

[0058] P 顺=226544.034Pa=0.227MPa.

[0059] In the co-current feeding mode, the pressure on the enzyme column bed is P 逆 The feeding method used is as shown in the attached manual. Figure 2 The calculation formula is as follows:

[0060] P 逆 =ρgh+AP f1 +ΔP f2 +P 1 -P 2

[0061] That is, P 逆 =ρgh+ΔP f +P 1 -P 2

[0062] P 1 Take 0.18MPa, P 2 Take 0.20MPa

[0063] P 逆 =26544.0343Pa=0.027MPa.

[0064] It is measured by the above experiment that the compressive strength of the immobilized lipase column is about 213725.5Pa, i.e. 0.214MPa. It can be known from the above calculation that the pressure borne by the enzyme column under the co-current feeding mode is about 0.227MPa, which exceeds the strength that the enzyme column can withstand and will cause the destruction of the lipase, thereby greatly affecting the production cost; in addition, the pressure borne by the enzyme column under the countercurrent feeding mode is about 0.027MPa, which is much less than the compressive strength of the enzyme column. Therefore, the production process proposed in the present invention is reasonably and novelly designed, and can be better applied to the industrial production of medium and long-chain fatty acid edible oil.

[0065] Example 2

[0066] As the instruction manual Figure 3 As shown, a reaction device for preparing medium-chain fatty acid edible oil by a countercurrent feeding enzyme method provided by the present invention comprises a raw material mixing tank 1, a pre-processor 3, a fixed bed reactor 5, a post-processor 9 and a storage tank 10 connected in sequence;

[0067] The raw material mixing tank 1 is provided with a heating and stirring device 2, which can heat, melt and evenly mix the reaction raw materials in the raw material mixing tank 1. The stirring device 2 is an ultrasonic stirrer, and the heating device is a heating sleeve 11, which is wrapped around the outer wall of the raw material mixing tank 1;

[0068] The pre-processor 3 is filled with an adsorbent for removing free fatty acids and peroxides in the reaction raw materials;

[0069] The catalyst filled in the fixed bed reactor 5 is immobilized lipase;

[0070] A nitrogen stripping process is performed in the post-processor 9 to decolorize, deacidify and deodorize the reaction product;

[0071] The pretreatment device 3 is connected to the fixed bed reactor 5 through a pipeline, and the pipeline includes a main pipeline, a side branch pipeline 1 and a side branch pipeline 2. The main pipeline is connected to the side branch pipeline 1 and the side branch pipeline 2 through a tee and are interconnected. A flow valve is provided on each of the side branch pipelines 1 and 2. A first screw pump 4 is provided on the main pipeline. The side branch pipeline 1 is connected to the first feed port 16 on the fixed bed reactor 5, and the side branch pipeline 2 is interconnected with the second feed port 17 at the bottom of the fixed bed reactor 5.

[0072] The auxiliary branch pipeline 1 and the auxiliary branch pipeline 2 are each provided with a pressure gauge for real-time monitoring of the fluid pressure in the pipeline.

[0073] The top of the fixed bed reactor 5 is provided with an air inlet 18 and an exhaust valve 19, and the air inlet 18 is interconnected with the gas blowing device through a flow valve control, and the middle and bottom of the fixed bed reactor 5 are respectively provided with a first discharge port 20 and a second discharge port 21, the first discharge port 20 is interconnected with the third feed port in the middle of the post-processor 9 through a first branch, the second discharge port 21 is interconnected with the waste tank 8 through a second branch, and the first branch and the second branch are interconnected through a third branch;

[0074] Three valves are installed on the first branch, namely the first valve 28, the second valve 29, and the third valve 30. The first valve 28 is adjacent to the first discharge port 20, the second valve 29 is adjacent to the left side of the connection between the third branch and the first branch, and the third valve 30 is adjacent to the connection between the first branch and the post-processor 9.

[0075] The second branch is provided with two valves, namely a fourth valve 31 and a fifth valve 32. The fourth valve 31 is located immediately below the fourth discharge port, and the fifth valve 32 is located immediately to the right of the connection port between the third branch and the second branch;

[0076] The third branch is provided with two valves, namely a sixth valve 33 and a seventh valve 34. The sixth valve 33 is adjacent to the connection port between the third branch and the second branch, and the seventh valve 34 is adjacent to the connection port between the first branch and the third branch.

[0077] A second screw pump 7 is provided on the first branch between the first valve 28 and the second valve 29 , and a third screw pump 6 is provided on the second branch on the left side of the connection between the second branch and the third branch near the second discharge port 21 .

[0078] The immobilized lipase in the fixed bed reactor 5 is filled in intervals along the vertical direction to form enzyme columns, and adjacent enzyme columns are isolated by horizontally arranged microporous partitions 24, and the microporous partitions 24 do not allow the immobilized lipase to pass through.

[0079] There are three enzyme columns arranged along the vertical direction of the fixed bed reactor 5 .

[0080] The thickness of the microporous separator 24 is 2 mm, and the pore density is 200 pores / cm 2 The pore size is 10 μm. A temperature sensor 25 is fixedly mounted on the microporous partition plate 24 .

[0081] The adsorbent in the pre-processor 3 is an activated carbon particle layer and a silica particle layer alternately filled along the vertical direction of the pre-processor 3. The height of a single activated carbon particle layer is 1m, and the height of a single silica particle layer is 1m. The average particle size of the activated carbon is 1mm, and the average particle size of the silica is 0.5mm. There are two activated carbon particle layers.

[0082] The fixed bed reactor 5 comprises an inner tube 22 and an outer tube, wherein the outer tube is sleeved on the outer side of the inner tube 22, and an annular cavity 23 is formed circumferentially between the outer tube and the inner tube 22, and a medium outlet 27 and a medium inlet 26 are respectively provided at the upper and lower parts of the annular cavity 23, the top of the inner tube 22 is interconnected with the first feed port 16, the air inlet 18 and the exhaust valve 19, and the bottom of the inner tube 22 is provided with the first feed port 16 and the second discharge port 21. Liquid or steam medium can enter the annular cavity 23 from the inlet, and then flow out of the annular cavity 23 through the outlet, and the inner tube 22 can be kept warm by continuously introducing a medium with a certain temperature into the annular cavity 23.

[0083] The above reaction device is used to prepare medium-chain fatty acid edible oil, and the specific steps are as follows:

[0084] (1) Add the reaction raw materials into the raw material mixing tank 1, heat, melt, stir and mix them evenly, then transfer the liquid material in the raw material mixing tank 1 to the pretreatment device 3 for pretreatment to remove free fatty acids and peroxides in the liquid material, and the liquid material treated by the pretreatment device 3 is divided into two streams and enters the inner tube 22 of the fixed bed reactor 5 from the first feed port 16 and the second feed port 17 on the fixed bed reactor 5 to carry out ester exchange reaction. After the ester exchange reaction is completed, open all valves on the first branch so that part of the reaction product in the fixed bed reactor 5 is pumped into the post-processor 9, then close the first valve 28 and the second valve 29 on the first branch, and then open the fourth valve 31 on the second branch and all valves on the third branch so that the reaction product remaining at the bottom of the fixed bed reactor 5 is pumped into the post-processor 9, then close the third valve 30 on the first branch, and the reaction product in the post-processor 9 is decolorized, deacidified and deodorized by nitrogen stripping process, and then transferred to the storage tank 10;

[0085] (2) After all the reaction products in the post-processor 9 in step 1 enter the storage tank 10, open the fifth valve 32 on the second branch, close all the valve switches on the third branch, close all the valve switches on the first branch, and use a gas blowing device to blow nitrogen or inert gas into the fixed bed reactor 5 to blow the grease impurities remaining in the pores of the enzyme column in the fixed bed reactor 5 into the waste tank 8. After the blowing is completed, close all the valves on the second branch.

[0086] The reaction raw material is a mixture of soybean oil, coconut oil and food-grade caprylic and capric triglyceride in a mass ratio of 11:8:1.

[0087] The fixed bed reactor 5 is 10 m high and has a reaction column diameter of 2 m. The immobilized lipase in the fixed bed reactor 5 is food-grade immobilized lipase Lipozyme TLIM. The total loading amount of the immobilized lipase in the fixed bed reactor 5 is 7% of the total mass of the reaction raw materials. All the immobilized lipases are evenly divided into three portions and loaded in the fixed bed reactor 5 to form three completely identical enzyme columns.

[0088] The flow ratio of the two liquid materials entering the inner tube 22 of the fixed bed reactor 5 is 1:1, and the flow rate of each liquid material is 0.057m 3 / h.

[0089] The heating temperature in the raw material mixing tank 1 is 25° C., the stirring device 2 in the raw material mixing tank 1 is an ultrasonic stirrer, and the constant reaction temperature in the inner tube 22 of the fixed bed reactor 5 is 70° C. After the reaction, the content of medium-chain fatty acid structure ester MLCT in the product is measured to be 79.3%, and the acid value of the product is 2.98 mgKOH / g. After purification and refining, the MLCT content in the final product can reach 96.7%, the acid value can be reduced to 0.081 mgKOH / g, and the peroxide value is 0.654 mmol / kg. All indicators meet the quality indicators of medium-chain fatty acid edible oil.

[0090] Example 3 is the same as Example 2, except that the reaction raw material in Example 3 is a mixture of soybean oil, coconut oil and food-grade caprylic acid triglyceride in a mass ratio of 10:9:1. After the reaction, the content of medium-chain fatty acid structure ester MLCT in the product was measured to be 80.57%, and the product acid value was 1.9 mgKOH / g. After purification and refining, the MLCT content in the final product can reach 96.89%, the acid value can be reduced to 0.069 mgKOH / g, and the peroxide value is 0.266 mmol / kg. All indicators meet the quality indicators of medium-chain fatty acid edible oil.

[0091] During the transesterification reaction, samples were taken hourly. After 4.5 hours of reaction, the MLCT content in the product reached a maximum of 74.57%, and the acid value was 5.51 mgKOH / g.

[0092] Example 4 is the same as Example 2, except that in Example 4, the flow rates of the two liquid materials pumped into the fixed bed reactor 5 from the second feed port 17 and the third feed port are both 0.01 m 3 / h. After the reaction, the content of medium-chain fatty acid structure ester MLCT in the product was measured to be 80.69%, and the acid value of the product was 2.66mgKOH / g. After purification and refining, the MLCT content in the final product could reach 97%, the acid value could be reduced to 0.073mgKOH / g, and the peroxide value was 0.491mmol / kg. All indicators met the quality indicators of medium-chain fatty acid edible oil.

[0093] Example 5 is the same as Example 2, except that in Example 5, the flow rates of the two liquid materials pumped into the fixed bed reactor 5 from the second feed port 17 and the third feed port are both 0.066 m 3 / h. The content of medium-chain fatty acid structure ester MLCT in the product was measured to be 81.36%, and the acid value of the product was 2.12mgKOH / g. After purification and refining, the MLCT content in the final product could reach 98.1%, the acid value could be reduced to 0.065mgKOH / g, and the peroxide value was 0.256mmol / kg. All indicators met the quality indicators of medium-chain fatty acid edible oil.

[0094] Example 6 is the same as Example 2, except that the reaction raw material in Example 6 is a mixture of soybean oil, coconut oil and food-grade caprylic acid triglyceride in a mass ratio of 12:7:1. After the reaction is completed, the content of medium-chain fatty acid edible oil MLCT in the product is measured to be 76.16%, and the product acid value is 2.82 mgKOH / g. After purification and refining, the MLCT content in the final product can reach 94.1%, the acid value can be reduced to 0.079 mgKOH / g, and the peroxide value is 0.556 mmol / kg. All indicators meet the quality indicators of medium-chain fatty acid edible oil.

[0095] Example 7 is the same as Example 2, except that the reaction temperature in the fixed bed reactor 5 in Example 7 is 75° C. After the reaction, the content of medium-chain fatty acid structure ester MLCT in the product is measured to be 81.93%, and the acid value of the product is 2.1 mgKOH / g. After purification and refining, the MLCT content in the final product can reach 98.5%, the acid value can be reduced to 0.066 mgKOH / g, and the peroxide value is 0.240 mmol / kg. All indicators meet the quality indicators of medium-chain fatty acid edible oil.

[0096] Comparative Example 1 is the same as Example 2, and the reaction raw materials are a mixture of soybean oil, coconut oil, and food-grade caprylic and capric triglyceride in a mass ratio of 11:8:1. The difference is that Comparative Example 1 adopts a unidirectional downstream feeding method and a reactor with a stirring paddle (the structure is as shown in the attached manual) Figure 4 As shown) for transesterification reaction, the feed flow rate of the raw material is 0.114m 3 During the transesterification reaction, samples were taken hourly, and the MLCT content in the product continued to increase from 1h to 4h. When the reaction reached 4h, the MLCT content in the product reached a maximum of 67.97%, and the acid value was 6.72mgKOH / g.

[0097] Comparative Example 2 is the same as Example 6, and the reaction raw materials are a mixture of soybean oil, coconut oil, and food-grade caprylic and capric triglyceride in a mass ratio of 12:7:1. The difference is that Comparative Example 2 adopts a unidirectional downstream feeding method and a reactor with a stirring paddle (the structure is as shown in the attached manual) Figure 4 As shown) for transesterification reaction, the feed flow rate of the raw material is 0.114m 3 During the transesterification reaction, samples were taken hourly, and the MLCT content in the product continued to increase from 1h to 3h. When the reaction reached 3h, the MLCT content in the product reached the highest, which was only 65.13%, and the acid value was 7.31mgKOH / g.

[0098] Comparative Example 3 is the same as Example 2, except that in Comparative Example 3, the liquid material in the preprocessor 3 is pumped into the fixed bed reactor for transesterification reaction in a unidirectional downstream feeding manner, and the flow rate of the liquid material is 0.114m 3 After the reaction was completed, the content of medium-chain fatty acid structure ester MLCT in the product was measured to be 67.97%, and the acid value was 6.72 mgKOH / g.

[0099] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A reaction device for preparing medium-chain fatty acid edible oil by a countercurrent feeding enzyme method, characterized in that: It comprises a raw material mixing tank (1), a pre-processor (3), a fixed bed reactor (5), a post-processor (9) and a storage tank (10) which are connected in sequence; The raw material mixing tank (1) is provided with a heating and stirring device (2); The pre-processor (3) is filled with an adsorbent for removing free fatty acids and peroxides in the reaction raw materials; The catalyst filled in the fixed bed reactor (5) is immobilized lipase; Refining and purification are carried out in a post-processor (9); The pretreatment device (3) is connected to the fixed bed reactor (5) through a pipeline, wherein the pipeline comprises a main pipeline, a first branch pipeline and a second branch pipeline, wherein the main pipeline is connected to the first branch pipeline and the second branch pipeline through a tee and are connected to each other, wherein the first branch pipeline and the second branch pipeline are each provided with a flow valve, which are a first flow valve (12) and a second flow valve (13), respectively, and the main pipeline is provided with a first screw pump (4). The first branch pipeline is connected to a first feed port (16) on the fixed bed reactor (5), and the second branch pipeline is connected to a second feed port (17) at the bottom of the fixed bed reactor (5).

2. The reaction device for preparing medium-chain fatty acid edible oil by a countercurrent feeding enzyme method according to claim 1, characterized in that: The auxiliary branch pipeline 1 and the auxiliary branch pipeline 2 are each provided with a pressure gauge, namely a first pressure gauge (14) and a second pressure gauge (15), which are used to monitor the fluid pressure in the pipeline in real time.

3. The reaction device for preparing medium- and long-chain fatty acid edible oil by a countercurrent feeding enzyme method according to claim 1, characterized in that: The top of the fixed bed reactor (5) is provided with an air inlet (18) and an exhaust valve (19), the air inlet (18) is connected to the gas blowing device through a flow valve control, the middle and bottom of the fixed bed reactor (5) are respectively provided with a first discharge port (20) and a second discharge port (21), the first discharge port (20) is connected to the third feed port in the middle of the post-processor (9) through a first branch, the second discharge port (21) is connected to the waste tank (8) through a second branch, and the first branch and the second branch are connected to each other through a third branch; Three valves are installed on the first branch, namely a first valve (28), a second valve (29), and a third valve (30). The first valve (28) is adjacent to the first discharge port (20), the second valve (29) is adjacent to the left side of the connection port between the third branch and the first branch, and the third valve (30) is adjacent to the connection port between the first branch and the post-processor (9); The second branch is provided with two valves, namely a fourth valve (31) and a fifth valve (32), wherein the fourth valve (31) is located immediately below the fourth discharge port, and the fifth valve (32) is located immediately to the right of the connection port between the third branch and the second branch; The third branch is provided with two valves, namely a sixth valve (33) and a seventh valve (34), the sixth valve (33) being adjacent to a connection port between the third branch and the second branch, and the seventh valve (34) being adjacent to a connection port between the first branch and the third branch; A second screw pump (7) is arranged on the first branch between the first valve (28) and the second valve (29), and a third screw pump (6) is arranged on the second branch on the left side of the connection between the second branch and the third branch on the side close to the second discharge port (21).

4. The reaction device for preparing medium-chain fatty acid edible oil by a countercurrent feeding enzyme method according to claim 1, characterized in that: The immobilized lipase in the fixed bed reactor (5) is filled in intervals along the vertical direction in the fixed bed reactor (5) to form enzyme columns, and adjacent enzyme columns are isolated by horizontally arranged microporous partitions (24), and the microporous partitions (24) do not allow the immobilized lipase to pass through.

5. The reaction device for preparing medium-chain fatty acid edible oil by a countercurrent feeding enzyme method according to claim 4, characterized in that: At least three enzyme columns are arranged along the vertical direction of the fixed bed reactor (5).

6. The reaction device for preparing medium- and long-chain fatty acid edible oil by a countercurrent feeding enzyme method according to claim 4, characterized in that: The thickness of the microporous separator (24) is 2-6 mm, and the pore density is 200-600 pores / cm 2 , the pore size is 10-50μm.

7. The reaction device for preparing medium-chain fatty acid edible oil by a countercurrent feeding enzyme method according to claim 1, characterized in that: The adsorbent in the pre-processor (3) is an activated carbon particle layer and a silicon dioxide particle layer alternately filled along the vertical direction of the pre-processor (3), the height of a single activated carbon particle layer is 1-1.5m, the height of a single silicon dioxide particle layer is 1-1.5m, the average particle size of the activated carbon is 1-4mm, the average particle size of the silicon dioxide is 0.5-2mm, and the number of activated carbon particle layers is at least two.

8. The reaction device for preparing medium-chain fatty acid edible oil by enzymatic method using countercurrent feeding according to claim 1, characterized in that: The immobilized lipase includes one or a combination of two or more of Lipozyme 435, Lipozyme FLex, Lipozyme TLIM and Lipozyme RMC.

9. The reaction device for preparing medium- and long-chain fatty acid edible oil by a countercurrent feeding enzyme method according to claim 1, characterized in that: The fixed bed reactor (5) comprises an inner tube (22) and an outer tube, wherein the outer tube is sleeved on the outer side of the inner tube (22), and an annular cavity (23) is formed circumferentially between the outer tube and the inner tube (22). An outlet and an inlet are respectively arranged at the upper and lower parts of the annular cavity (23), the top of the inner tube (22) is interconnected with a first feed port (16), an air inlet (18) and an exhaust valve (19), and the bottom of the inner tube (22) is provided with a first feed port (16) and a second discharge port (21).

10. A method for preparing medium- and long-chain fatty acids by a countercurrent enzymatic method, characterized in that: The reaction device according to any one of claims 1 to 9 is used, and specifically comprises the following steps: (1) Add the reaction raw materials into the raw material mixing tank (1) and heat, melt, stir and mix them evenly. Then, transfer the liquid material in the raw material mixing tank (1) to the pretreatment device (3) for pretreatment to remove free fatty acids and peroxides in the liquid material. The liquid material treated by the pretreatment device (3) is divided into two streams and enters the inner tube (22) of the fixed bed reactor (5) from the first feed port (16) and the second feed port (17) on the fixed bed reactor (5) respectively to carry out ester exchange reaction. After the ester exchange reaction is completed, open all valves on the first branch. A portion of the reaction product in the fixed bed reactor (5) is pumped into the post-processor (9), and then the first valve (28) and the second valve (29) on the first branch are closed, and then the fourth valve (31) on the second branch and all valves on the third branch are opened, so that the remaining reaction product at the bottom of the fixed bed reactor (5) is pumped into the post-processor (9), and then the third valve (30) on the first branch is closed. The reaction product in the post-processor (9) is decolorized, deacidified and deodorized by a nitrogen stripping process, and then transferred to a storage tank (10); (2) After all the reaction products in the post-processor (9) in step (1) enter the storage tank (10), open the fifth valve (32) on the second branch, close all valves on the third branch, close all valves on the first branch, use a gas blowing device to blow nitrogen or inert gas into the fixed bed reactor (5), blow the grease impurities remaining in the pores of the enzyme column in the fixed bed reactor (5) into the waste tank (8), and after the blowing is completed, close all valves on the second branch; (3) Then, the reaction raw materials are replaced and steps (1)-(2) are repeated to obtain different types of medium- and long-chain fatty acids.

Images