Oiling agent for producing lyocell fibers, oiling agent circulating system and preparation process

Abstract

The invention provides an oil agent for producing lyocell fibers, an oil agent circulating system and a preparation process. The oil agent comprises one or more of mineral oil, synthetic oil and natural grease; a bleaching and sterilizing component is mixed in the oiling agent. The oiling agent mixed with the bleaching and sterilizing component is adopted, the bleaching and sterilizing component bleaches and sterilizes the lyocell fibers in the oiling process while bleaching and sterilizing the oiling agent body in the recycling process, and the one-step process of oiling, bleaching and sterilizing the fibers is achieved. Experimental results show that the whiteness of the lyocell fiber obtained by adopting the oil agent mixed with the ozone can be improved by 2%-4%.

Description

Technical Field

[0001] This invention belongs to the field of lyocell fiber spinning production, and particularly relates to an oiling agent, an oiling agent circulation system, and a preparation process for producing lyocell fibers. Background Technology

[0002] Due to its inherent properties, lyocell fiber must be oiled before it can be used downstream. Therefore, oiling is typically performed after refining and washing during the lyocell spinning process. Because the oiling agent is recycled during production, it is prone to bacterial growth. Bacterial proliferation produces flocculent, viscous secretions that adhere to the fiber surface, reducing fiber whiteness and affecting the product's appearance. Furthermore, excessive bacterial growth can also pose safety risks to the product.

[0003] On the other hand, the low whiteness of Lyocell fiber products, limited by the whiteness of raw materials and the color of solvents, greatly affects their application in high-end scenarios. In particular, since Lyocell fiber began to be used in face masks and medical nonwoven fabrics, higher requirements have been placed on the whiteness and safety of Lyocell fiber. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide an oiling agent, an oiling agent circulation system and a preparation process for producing lyocell fibers, wherein the oiling agent can achieve oiling, bleaching and sterilization of lyocell fibers in one step.

[0005] The present invention provides an oiling agent for the production of lyocell fibers, the oiling agent comprising one or more of mineral oil, synthetic oil and natural oils; the oiling agent is mixed with bleaching and bactericidal components.

[0006] Preferably, the bleaching and sterilizing ingredients include one or more of ozone, hydrogen peroxide, and hypochlorous acid.

[0007] Preferably, the concentration of ozone incorporated into the oil is 0.1~2.0 mg / L.

[0008] The present invention provides an oil circulation system for the production of lyocell fibers, including a device for adding bleaching and sterilizing components to an oil mixing device.

[0009] Preferably, the device includes an ozone generating device.

[0010] This invention provides a process for preparing lyocell fibers, comprising the following steps:

[0011] The oiling agent described in the above technical solution is used to oil lyocell fibers;

[0012] The oil agent includes one or more of mineral oil, synthetic oil and natural oil; the oil agent is mixed with bleaching and bactericidal components.

[0013] Preferably, the bleaching and sterilizing ingredients include one or more of ozone, hydrogen peroxide, and hypochlorous acid.

[0014] Preferably, the oil is a recyclable oil; the circulation flow rate of the oil is 40~80m³. 3 / h.

[0015] Preferably, the temperature for recycling the oil is 50℃~60℃, and the pH value of the recycled oil is 6~8.

[0016] Preferably, the bleaching and sterilizing component is ozone; the ozone-infused oil is prepared by recycling oil and ozone in a closed oil mixing device;

[0017] The flow rate of ozone delivered to the oil mixing equipment is 10~200L / min;

[0018] The concentration of the circulating oil in the oil mixing equipment is 5~15g / L.

[0019] Preferably, an oil preparation device is connected to the oil mixing equipment;

[0020] The concentration of the oil in the oil preparation device is 60~150g / L.

[0021] This invention provides an oiling agent for producing lyocell fibers, comprising one or more of mineral oil, synthetic oil, and natural oils; the oiling agent is infused with bleaching and sterilizing components. This invention uses an oiling agent infused with bleaching and sterilizing components, which simultaneously bleach and sterilize the lyocell fibers during the oiling process while the oiling agent itself is recycled, achieving a one-step process for fiber oiling, bleaching, and sterilization. Experimental results show that the whiteness of lyocell fibers obtained using an ozone-infused oiling agent can be increased by 2% to 4%. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the oil circulation system for producing lyocell fibers according to the present invention;

[0023] Figure 2 This is a flowchart illustrating the preparation process of lyocell fiber according to the present invention. Detailed Implementation

[0024] The present invention provides an oiling agent for the production of lyocell fibers, the oiling agent comprising one or more of mineral oil, synthetic oil and natural oils; the oiling agent is mixed with bleaching and bactericidal components.

[0025] The bleaching and sterilizing ingredients described in this invention include one or more of ozone, hydrogen peroxide, and hypochlorous acid. The ozone is physically adsorbed onto the oil-based agent. The hydrogen peroxide and hypochlorous acid exist in a mixture with the oil-based agent. This invention utilizes the strong oxidizing properties of the aforementioned bleaching and sterilizing ingredients to achieve bleaching and sterilization effects on the fibers.

[0026] The lyocell fiber produced in this invention is mainly composed of cellulose; it is a regenerated cellulose fiber spun using N-methylmorpholine-N-oxide (NMMO) as a solvent through a wet spinning process. The oiling step in the production of lyocell fiber in this invention requires treating the fiber with an oiling agent to increase its smoothness and spinnability. However, during the use of the oiling agent, colored substances produced by fiber decomposition and residual natural pigments from the pulp enter the oiling agent. As the process continues, these colored substances affect the whiteness of the final lyocell fiber product. Therefore, this invention uses an oiling agent incorporating bleaching and sterilizing components. These components oxidize and decompose the aforementioned natural pigments and colored substances, improving the whiteness of the lyocell fiber while simultaneously achieving a sterilization effect.

[0027] The concentration of ozone in the oil agent described in this invention is 0.1~2.0 mg / L, specifically 0.1 mg / L, 0.2 mg / L, 0.3 mg / L, 0.4 mg / L, 0.5 mg / L, 0.6 mg / L, 0.7 mg / L, 0.8 mg / L, 0.9 mg / L, 1.0 mg / L, 1.1 mg / L, 1.2 mg / L, 1.3 mg / L, 1.4 mg / L, 1.5 mg / L, 1.6 mg / L, 1.7 mg / L, 1.8 mg / L, 1.9 mg / L, or 2.0 mg / L.

[0028] The present invention provides an oil circulation system for the production of lyocell fibers, including a device for adding bleaching and sterilizing components to an oil mixing device.

[0029] The device described in this invention includes an ozone generating device 1.

[0030] See Figure 1 , Figure 1 This is a schematic diagram of the oil circulation system for producing lyocell fiber according to the present invention; wherein, 1 is an ozone generating device, 2 is an oil preparation device, 3 is an oil mixing device, 4 is an oiling device, 5 is an ozone delivery pipeline valve, 6 is an oil mother liquor flow control valve, 7 is an oil circulation flow control valve, and 8 is an oil circulation pipeline.

[0031] The oil circulation system provided by the present invention includes an ozone generating device 1, which generates and stores ozone with a concentration of 10~30 mg / L; the present invention uses oxygen as raw material and uses an ozone generator to generate ozone.

[0032] The oil circulation system provided by this invention also includes an oil mixing device 3 connected to the ozone generating device 1, specifically an oil mixing tank. An ozone delivery pipeline valve 5 is installed on the connecting pipe between the ozone generating device 1 and the oil mixing device 3.

[0033] The oil mixing device 3 described in this invention is a closed system to prevent ozone leakage. The oil in the oil mixing device 3 receives and mixes with ozone generated by the ozone generating device 1, with an ozone delivery flow rate of 20-300 L / min. The temperature of the oil inside the oil mixing device 3 is 50-60℃; the pH value of the oil is 6-8. The circulation flow rate of the oil is 40-80 m³ / min. 3 / h.

[0034] The present invention controls the flow rate of ozone added to the oil mixing device 3 by controlling the ozone delivery pipeline valve 5, thereby indirectly controlling the ozone concentration in the oil mixing device 3, so that the ozone concentration in the oil in the oil mixing device 3 is 0.1~2.0mg / L.

[0035] The oil circulation system provided by the present invention also includes an oil preparation device 2 connected to the oil mixing device 3; in a specific embodiment, an oil mother liquor flow control valve 6 is provided on the connecting pipe between the oil preparation device 2 and the oil mixing device 3.

[0036] The oiling agent circulation system provided by this invention also includes an oiling device 4 connected to the oiling agent mixing equipment 3. After being treated with added mother liquor and ozone, the oiling agent in the oiling agent mixing equipment 3 is transported to the oiling device 4 to wash the Lyocell fibers for oiling. After washing and rolling out excess oiling agent, the fibers enter the next process for drying along the conveyor chain, and the rolled-out oiling agent flows back to the oiling agent mixing equipment 3. An automatic control valve 7 for oiling agent circulation flow is installed on the connecting pipe between the oiling agent mixing equipment 3 and the oiling device 4. In the fiber oiling process, ozone mixed in the oiling agent circulation liquid bleachs and sterilizes the Lyocell fibers.

[0037] In this invention, the oiling device 4 is connected to the oil mixing equipment 3 via an oil circulation pipe 8. The oil in the oiling device is continuously transported to the oil mixing equipment through the oil circulation pipe for further recycling.

[0038] The oiling device 4 used in this invention is a semi-enclosed device with an exhaust fan inside that continuously exhausts air to maintain a negative pressure state inside the device, so as to promptly discharge any ozone that may separate from the oil.

[0039] In this invention, the oil preparation device 2, the oil mixing device 3, and the oiling device 4 are all connected by pipelines.

[0040] This invention provides a process for preparing lyocell fibers, comprising the following steps:

[0041] The oiling agent described in the above technical solution is used to oil lyocell fibers;

[0042] The oil agent includes one or more of mineral oil, synthetic oil and natural oil; the oil agent is mixed with bleaching and bactericidal components.

[0043] join Figure 2 The process for preparing lyocell fibers in this invention mainly includes preparing slurry, solvent mixing, high-temperature dissolution, filtration, extrusion, stretching, curing, washing, and oiling.

[0044] In this invention, the preparation of the pulp mainly involves using hardwoods, such as eucalyptus, pine, and birch, to produce wood pulp. The solvent mixing process includes pulverizing the wood pulp and mixing it with NMMO to obtain a mixture. The mixture is heated and dissolved at 95-105°C, and the cellulose in the wood pulp forms a viscous, uniform spinning solution in the NMMO. The dissolved spinning solution is filtered to remove undissolved cellulose particles and impurities, resulting in a clear spinning solution. The spinning solution is extruded through a spinneret to form a fine stream. The fine stream of spinning solution forms an air gap in the air, is cooled and stretched for orientation, and then enters a coagulation bath where the solvent is extracted, and the cellulose recrystallizes and solidifies. The newly formed fibers are washed with deionized water to remove residual NMMO. The washed fibers are cut and oiled through the oiling device 4 in the above-mentioned oiling agent circulation system, and finally dried to obtain lyocell fibers.

[0045] Lyocell fiber is made from wood pulp, which retains some natural pigments. During the lyocell spinning process, low-molecular-weight cellulose and sugars from the spinning solution remain in the solvent NMMO and subsequent rinsing water. These substances can decompose, leading to bacterial and fungal growth and the formation of white or red flocculent substances. These substances cannot be completely removed during washing, leaving some residue that affects fiber whiteness. Furthermore, these substances from the fiber can also enter the oiling agent circulation system. Additionally, the spinning solution temperature in the lyocell fiber production process is relatively high at 100-110℃. During processing and transportation, a small amount of cellulose and NMMO solvent in the solution decomposes, producing colored substances, which is also one of the main reasons affecting the whiteness of lyocell fibers.

[0046] In existing technologies, during the recycling process of oiling agents, pigments and other substances from the fibers are carried into the oiling agent. This invention addresses this by incorporating bleaching and bactericidal components into the oiling agent, which oxidize these pigments and also sterilize the oiling agent, allowing for recycling and reducing costs. The bleaching and bactericidal components also oxidize and decompose colored substances in the lyocell fibers that decompose at high temperatures, achieving a sterilization effect simultaneously. These bleaching and bactericidal components bleach and sterilize both the oiling agent and the lyocell fibers, resulting in improved whiteness and sterilization of the lyocell fibers during oiling.

[0047] This invention employs an oiling agent incorporating bleaching and bactericidal components to oil lyocell fibers. The oiling agent used primarily includes one or more of mineral oil, synthetic oil, and natural oils; it also includes one or more of antistatic agents, emulsifiers, and auxiliary smoothing / bundling agents. Oiling lyocell fibers forms a thin film on the fiber surface, which reduces friction between fibers, improves smoothness and spinnability, and prevents entanglement and breakage during subsequent processing, thereby improving production efficiency and product quality. The oiling agent can improve the processing performance of the fibers, enhance their physicochemical properties, and impart special functions such as rheological properties, viscosity, adhesion, and mechanical properties.

[0048] The oiling agent used in this invention, by mass fraction, preferably comprises 40-70% mineral oil or polydimethylsiloxane (PDMS); 10-25% antistatic agent; 0-5% emulsifier; and 5-10% auxiliary smoothing / bundling agent. The mineral oil used in this invention is white oil; the smoothing agent reduces the coefficient of friction and protects the fibers. The antistatic agent used in this invention is selected from saturated alkyl phosphate salts, or saturated alkyl sulfates / sulfonates, or saturated alkyl quaternary ammonium salts; the antistatic agent eliminates static electricity accumulation. The emulsifier used in this invention is selected from saturated fatty alcohol polyoxyethylene ethers; the emulsifier helps form a stable emulsion and ensures uniform adhesion. The auxiliary smoothing / bundling agent used in this invention is selected from saturated fatty acid esters; the auxiliary smoothing / bundling agent improves the smoothness and bundle properties of lyocell fibers. This invention achieves a one-step process of fiber oiling, bleaching, and sterilization by incorporating bleaching and sterilizing components into the oiling agent containing the above components.

[0049] The bleaching and bactericidal components in the oiling agent of this invention are selected from one or more of ozone, hydrogen peroxide, and hypochlorous acid. In a specific embodiment of this invention, ozone is added to the oiling agent, and the ozone is physically attached to the oiling agent. Subsequently, as the oiling agent is applied to the fibers, the ozone can oxidize and decompose the residual pigments in the fibers or the colored substances in the adhesive, thereby improving the whiteness of the fibers and achieving a bactericidal effect.

[0050] In this invention, the ozone-infused oil is prepared by recycling oil and ozone in a closed oil mixing device 3;

[0051] The ozone flow rate delivered to the oil mixing device 3 in this invention is 20~300 L / min, specifically 20 L / min, 25 L / min, 30 L / min, 35 L / min, 40 L / min, 45 L / min, 50 L / min, 55 L / min, 60 L / min, 65 L / min, 70 L / min, 75 L / min, 80 L / min, 85 L / min, 90 L / min, 95 L / min, 100 L / min, 105 L / min, 110 L / min, 120 L / min, 130 L / min, 140 L / min, 50 L / min, 160 L / min, 170 L / min, 80 L / min, 190 L / min, 200 L / min, 210 L / min, 220 L / min, 230 L / min, 240 L / min, 250 L / min, 26 ... L / min, 270 L / min, 280 L / min, 290 L / min, or 300 L / min.

[0052] The oil in the oil mixing device 3 of this invention is a recycled oil; the concentration of the recycled oil is 5~15 g / L, specifically 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L, 10 g / L, 11 g / L, 12 g / L, 13 g / L, 14 g / L, or 15 g / L. The temperature of the oil in the oil mixing device 3 is 50~60℃, specifically 50℃, 52℃, 54℃, 56℃, 58℃, or 60℃; the pH value of the oil is 6~8, specifically 6, 7, or 8. The circulation flow rate of the oil is 40~80 m³ / h. 3 / h, specifically 40 m 3 / h, 45 m 3 / h, 50 m 3 / h、55 m 3 / h、60 m 3 / h、65 m 3 / h、70 m 3 / h, 75 m 3 / h or 80 m 3 / h.

[0053] In this invention, the ozone concentration mixed in the oil in the oil mixing device 3 is 0.1~2.0 mg / L, specifically 0.1 mg / L, 0.2 mg / L, 0.3 mg / L, 0.4 mg / L, 0.5 mg / L, 0.6 mg / L, 0.7 mg / L, 0.8 mg / L, 0.9 mg / L, 1.0 mg / L, 1.1 mg / L, 1.2 mg / L, 1.3 mg / L, 1.4 mg / L, 1.5 mg / L, 1.6 mg / L, 1.7 mg / L, 1.8 mg / L, 1.9 mg / L, or 2.0 mg / L.

[0054] The present invention includes an oil preparation device 2 connected to the oil mixing equipment 3. The concentration of the oil in the oil preparation device 2 is 60~150 g / L, specifically 60 g / L, 65 g / L, 70 g / L, 75 g / L, 80 g / L, 85 g / L, 90 g / L, 95 g / L, 100 g / L, 105 g / L, 110 g / L, 115 g / L, 120 g / L, 125 g / L, 130 g / L, 135 g / L, 140 g / L, 145 g / L, or 150 g / L. The base oil used in the oil preparation device 2 includes, but is not limited to, mineral oil or silicone oil, and other oils that are not easily oxidized. The flow rate of oil mother liquor added from oil preparation device 2 to oil mixing device 3 is 50~80 L / h, specifically 50 L / h, 55 L / h, 60 L / h, 65 L / h, 70 L / h, 75 L / h or 80 L / h.

[0055] The oil mixing device 3 described in this invention recovers excess oil from the rinsing of fibers and receives oil mother liquor from the oil preparation device 2 to adjust the oil concentration to 5-15 g / L. The flow rate of oil mother liquor added to the oil mixing device 3 is controlled by the oil mother liquor flow control valve 6 to maintain the oil concentration in the oil mixing device 3 between 5-15 g / L, specifically 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L, 10 g / L, 11 g / L, 12 g / L, 13 g / L, 14 g / L, or 15 g / L.

[0056] The preferred process flow provided by the present invention further includes solvent recovery: the NMMO solvent extracted from the coagulation bath is evaporated and concentrated, purified and then returned to the dissolving tank for reuse; the solvent recovery rate reaches more than 99%.

[0057] Existing production processes often result in bacterial growth in the oil used during recycling. Secretions adhere to the fiber surface, reducing whiteness and posing safety risks. This invention bleaches and sterilizes both the oil and the fiber during production, improving the whiteness of the resulting lyocell fiber.

[0058] Whiteness testing method: (Refer to GB / T 17644-2008 Test Method for Whiteness and Color of Textile Fibers)

[0059] a) Sample preparation: Take 3.0±0.1g of raw cotton after it has been loosened twice by the cotton analyzer and equilibrated in a constant temperature and humidity chamber. Arrange it evenly, spread it into the cotton loading device in one direction, and then push the cotton loading device into the whiteness meter to start the test.

[0060] b) Each sample was measured 3 times. After each measurement, the sample was rotated 120° before the next measurement.

[0061] c) After completing the three measurements, press the "Average" button to obtain and record the measured values.

[0062] To further illustrate the present invention, the following detailed description, in conjunction with embodiments, of an oiling agent, an oiling agent circulation system, and a preparation process for producing lyocell fibers, should not be construed as limiting the scope of protection of the present invention.

[0063] Example 1

[0064] During a planned maintenance shutdown, the lyocell production line with an annual capacity of 20,000 tons experienced a darkening of the spinning solution due to prolonged storage in pipes and sealed containers. This resulted in fibers with a low whiteness of only 74-76%, significantly lower than the normal fiber whiteness of 77-79%, rendering them unsellable. Furthermore, the prolonged storage of the oil in the 3-oil mixing equipment also led to bacterial growth and spoilage. Therefore, to prevent spoilage, ozone at a concentration of 10 mg / L was introduced into the 3-oil mixing equipment every 4 hours during the shutdown period, with the 5-ozone delivery pipeline valve opened for 2 minutes at a flow rate of 20 L / min. To ensure consistent product whiteness with normal production fibers after restarting, an ozone sterilization and bleaching process was used to bleach the fibers within the first 8 hours of operation.

[0065] The process parameters are as follows:

[0066] The 20 mg / L ozone from the 1-ozone generator is continuously supplied to the 3-oil mixing device at a flow rate of 100 L / min via the valve of the 5-ozone delivery pipeline.

[0067] 3. The ozone concentration added in the oil mixing equipment is 1~2 mg / L.

[0068] The concentration of the oil mother liquor added from the 2-oil preparation unit to the 3-oil mixing unit is 120 g / L, and the addition flow rate is 70 L / h.

[0069] 3. The concentration of the oil in the oil mixing equipment is 10 g / L, and the oil circulation flow rate is 60 m³ / L. 3 / h, oil temperature is 60℃, oil pH is 6.5.

[0070] After adopting the above process, the whiteness of the finished fiber produced within 8 hours of startup increased from 74-76% to 77-78%, reaching the standard for whiteness of fiber in normal production.

[0071] Example 2

[0072] The lyocell production line, with an annual output of 20,000 tons, has been converted from producing conventional spinning fibers to producing non-woven specialty fibers. Because non-woven specialty fibers have higher requirements for fiber cleanliness and whiteness, an ozone sterilization and bleaching process is required for production.

[0073] Standards for nonwoven special fibers: whiteness 81±2%; bacterial colony count ≤200cfu / g (value detected after 48h of incubation in a biochemical incubator); fungal colony count ≤100cfu / g (value detected after 7h of incubation in a biochemical incubator); water-soluble matter on fiber surface ≤0.6%.

[0074] The process parameters are as follows:

[0075] The 20 mg / L ozone from the 1-ozone generator and ozone storage device is continuously supplied to the 3-oil agent circulation tank at a flow rate of 50 L / min via the 5-ozone delivery pipeline valve.

[0076] 3. The ozone concentration added in the oil mixing equipment is 0.5~1.5 mg / L.

[0077] The concentration of the oil mother liquor added from the 2-oil preparation unit to the 3-oil mixing unit is 80 g / L, and the addition flow rate is 60 L / h.

[0078] 3. The concentration of the oil in the oil mixing equipment is 8 g / L, and the oil circulation flow rate is 40 m³ / L. 3 / h, oil temperature is 55℃, oil pH is 7.5.

[0079] After adopting the above process, the whiteness of the finished fiber increased from 77%~79% to 79%~81%; the bacterial colony count decreased from 108 cfu / g to 0; the fungal colony count decreased from 32 cfu / g to 0; and the water-soluble matter on the fiber surface decreased from 0.81% to 0.28%; all of which met the standards for nonwoven special fibers.

[0080] As can be seen from the above embodiments, the present invention provides an oiling agent for producing lyocell fibers, wherein the oiling agent includes one or more of mineral oil, synthetic oil, and natural oils; the oiling agent is infused with bleaching and sterilizing components. The present invention uses an oiling agent infused with bleaching and sterilizing components, which simultaneously bleach and sterilize the lyocell fibers during the oiling process while the oiling agent itself is recycled, achieving a one-step process for fiber oiling, bleaching, and sterilization. Experimental results show that the whiteness of lyocell fibers obtained using an ozone-infused oiling agent can be increased by 2% to 4%.

[0081] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An oiling agent for producing lyocell fibers, said oiling agent comprising one or more of mineral oil, synthetic oil, and natural oils; characterized in that, The oil contains bleaching and bactericidal components.

2. The oiling agent according to claim 1, characterized in that, The bleaching and sterilizing ingredients include one or more of ozone, hydrogen peroxide, and hypochlorous acid.

3. The oiling agent according to claim 2, characterized in that, The concentration of ozone added to the oil is 0.1~2.0 mg / L.

4. An oil circulation system for producing lyocell fibers, characterized in that, This includes devices for adding bleaching and sterilizing ingredients to oil mixing equipment.

5. The oil circulation system according to claim 4, characterized in that, The device includes an ozone generating device.

6. A process for preparing lyocell fiber, characterized in that, Including the following steps: Oiling of Lyocell fibers using the oiling agent described in any one of claims 1 to 3; The oil agent includes one or more of mineral oil, synthetic oil and natural oil; the oil agent is mixed with bleaching and bactericidal components.

7. The preparation process according to claim 6, characterized in that, The bleaching and sterilizing ingredients include one or more of ozone, hydrogen peroxide, and hypochlorous acid.

8. The preparation process according to claim 6, characterized in that, The oil is a recyclable oil; the circulation flow rate of the oil is 40~80m³. 3 / h.

9. The preparation process according to claim 8, characterized in that, The temperature for recycling the oil is 50℃~60℃, and the pH value for recycling the oil is 6~8.

10. The preparation process according to claim 8, characterized in that, The bleaching and sterilizing ingredients include ozone; the ozone-infused oil is produced by recycling oil and ozone in a closed oil mixing device; The flow rate of ozone delivered to the oil mixing equipment is 10~200L / min; The concentration of the circulating oil in the oil mixing equipment is 5~15g / L.

11. The preparation process according to claim 10, characterized in that, An oil preparation device connected to the oil mixing equipment; The concentration of the oil in the oil preparation device is 60~150g / L.

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