An efficient extraction process of camphor oil based on steam distillation

Abstract

This invention discloses a high-efficiency extraction process for camphor oil based on steam distillation, belonging to the field of plant essential oil extraction technology. The process includes the following steps: Step 1: Raw material pretreatment; Step 2: Three-stage countercurrent steam distillation; Step 3: Composite condensation recovery; Step 4: Refining and purification. Through differentiated optimization of particle size, pretreatment parameters, and distillation conditions, high-efficiency extraction of camphor leaves, branches, and trunks is achieved, solving the problem of large yield fluctuations in traditional mixed-raw material extraction processes.

Description

Technical Field

[0001] This invention relates to the field of plant essential oil extraction technology, specifically disclosing a high-efficiency extraction process for camphor oil based on steam distillation. Background Technology

[0002] Camphor oil is a natural essential oil extracted from the leaves, branches, and trunk of the camphor tree (Cinnamomum camphora), a plant belonging to the Lauraceae family. Its main components are camphor (40%-55%), eucalyptol (25%-35%), and linalool (5%-10%), and it is widely used in fragrances, pharmaceuticals, daily chemicals, and insect repellents. Currently, steam distillation is the mainstream technology for camphor oil extraction. This method has advantages such as simple equipment structure, no risk of solvent residue, and low production costs. However, existing technologies still have the following key technical defects, which seriously restrict its industrial application efficiency:

[0003] Low extraction efficiency: The traditional direct steam distillation process (such as the technology disclosed in CN113150873A) has an extraction cycle of 1.5-6 hours, and the yield of camphor oil is only 1.76%-2.025%. About 30%-40% of the essential oil in the raw material is wasted because it cannot be effectively separated.

[0004] Significant energy loss: Existing distillation equipment (such as single-stage distillation pots) has low steam utilization rate, and the essential oil volatilization loss rate during condensation reaches 15%-20%, with unit product energy consumption being more than 40% higher than that of solvent extraction.

[0005] Heat-sensitive components are easily destroyed: Traditional processes use high-temperature distillation at 98-100℃, which causes heat-sensitive components such as eucalyptol and linalool in camphor oil to undergo oxidative degradation, directly affecting the quality of the essential oil.

[0006] Poor raw material pretreatment: Simple crushing (20-40 mesh) or microwave pretreatment (MAHD process) cannot fully destroy the cell wall structure of camphor raw materials, resulting in limited steam mass transfer efficiency and insufficient release of essential oils;

[0007] Poor raw material compatibility: The existing process does not optimize process parameters for the structural differences of different raw materials such as leaves, branches and trunks, resulting in yield fluctuations of up to ±0.5% when extracting mixed raw materials and poor product stability.

[0008] Among existing improved technologies, CN113150873A discloses a direct steam distillation pot (1200mm in diameter and 2000mm in height), which improves loading and unloading efficiency and steam dispersion through a movable grid and a 90° elbow steam pipe, but does not solve the core problems of multi-stage mass transfer enhancement and condensation recovery optimization. The MAHD microwave-assisted process disclosed by the Chinese Academy of Agricultural Sciences in 2020, while increasing the yield to 3.26%, relies on a 786W high-power microwave device, resulting in high energy consumption and poor applicability in large-scale production scenarios in mountainous areas. Therefore, developing a steam distillation extraction process for camphor oil that is efficient, high-quality, and adaptable to multiple raw materials has become an urgent technical challenge in this field. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-efficiency extraction process for camphor oil based on steam distillation. Through technological innovations such as pretreatment synergistic optimization, distillation equipment structure improvement, and condensation recovery system upgrade, the yield of camphor oil can be ≥4.2% (leaf raw material), ≥3.8% (branch raw material), and ≥3.5% (dry raw material), with an extraction time of ≤60 minutes, while ensuring the retention rate of heat-sensitive components in the essential oil.

[0010] To achieve the above objectives, the present invention provides the following technical solution: a high-efficiency extraction process for camphor oil based on steam distillation, comprising the following steps:

[0011] Step 1: Raw material pretreatment. The raw materials are crushed and then subjected to low-temperature plasma treatment in a low-temperature plasma pretreatment chamber. The raw materials that have undergone low-temperature plasma treatment are then activated by microwave activation equipment.

[0012] Step 2: Three-stage countercurrent steam distillation. The raw material processed in Step 1 is subjected to three-stage countercurrent steam distillation using a three-stage countercurrent distillation column, and a gradient temperature and pressure system is used for control.

[0013] Step 3: Composite condensation and recovery. The camphor oil primary product obtained in Step 2 is recovered through a composite condensation and recovery system, which is a serpentine condenser and a plate condenser connected in series.

[0014] Step 4: Refining and purification.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] Synergistic Pretreatment: For the first time, the low-temperature plasma-microwave synergistic pretreatment parameters were optimized based on the structural characteristics of different raw materials such as leaves, branches and trunks, so that the cell wall damage rate reached 90% for camphor leaves, 88% for camphor branches and 85% for camphor trunks, effectively solving the technical problem of high steam mass transfer resistance in traditional pretreatment processes.

[0017] Multi-stage countercurrent distillation: Employing a three-stage gradient temperature-pressure distillation system, it precisely adapts to the essential oil release characteristics of different raw materials, increasing steam utilization by 45% compared to traditional single-stage distillation;

[0018] Composite condensation recovery system: It adopts a series structure of serpentine condenser and plate condenser with a condensation area of ​​5 square meters, which reduces the essential oil evaporation loss rate to 3%-5%, which is significantly better than the traditional single condensation process;

[0019] Multi-raw material compatibility: By optimizing the particle size, pretreatment parameters, and distillation conditions, efficient extraction of camphor leaves, branches, and trunks is achieved, solving the problem of large fluctuations in the extraction yield of mixed raw materials in traditional processes. Attached Figure Description

[0020] Figure 1 This is a partial cross-sectional schematic diagram of the low-temperature plasma pretreatment chamber of the present invention;

[0021] Figure 2 This is a partial cross-sectional schematic diagram of the three-stage countercurrent distillation column of the present invention;

[0022] Figure 3 This is a partial cross-sectional schematic diagram of the composite condensation recovery system of the present invention;

[0023] Figure 4 This is a schematic diagram of the overall process of the present invention.

[0024] In the diagram: Low-temperature plasma pretreatment chamber: 33 chamber body, 34 argon inlet, 35 flow regulating valve, 36 plasma generator, 37 discharge electrode, 38 needle electrode, 39 plate electrode, 40 conveyor, 41 temperature sensor, 42 raw material outlet, 43 feed trough, 44 exhaust port, 45 activated carbon filter.

[0025] Three-stage countercurrent distillation column: 6 column body, 8 steam distributor, 9 three-stage distillation space, 10 Z-shaped flow loop, 11 guide plate, 22 heat source chamber, 23 electric heater, 24 passage, 25 one-way valve, 26 multi-hole nozzle, 27 condenser surface, 29 raw material inlet, 30 sealing cover, 32 steam outlet;

[0026] Composite condensation recovery system: 12 serpentine condenser, 13 plate condenser, 14 centrifugal oil-water separator, 32 steam outlet, 48 cooling water inlet, 49 thermometer, 50 cooling water outlet, 51 flow meter, 52 mixed liquid collection tank, 53 level gauge, 54 temperature sensor, 55 steam inlet, 56 pressure sensor, 57 condensate outlet. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0028] A high-efficiency extraction process for camphor oil based on steam distillation includes the following steps:

[0029] Step 1: Raw material pretreatment. The raw materials are crushed, then subjected to low-temperature plasma treatment in a low-temperature plasma pretreatment chamber. Following this, the raw materials are further activated using microwave activation equipment.

[0030] (1) Screening and removing impurities: Select fresh camphor leaves with a moisture content of 12%-15%, dry branches with a moisture content of 14%-16%, or peeled tree trunks with a moisture content of 16%-18%, remove moldy, pest-infested and rotten parts, wash and air dry to the target moisture content range.

[0031] (2) Grinding and grading: A two-stage grinding process is adopted, and the particle size is controlled according to the differences in raw material type.

[0032] Camphor leaves: First-stage grinding 10-15 mesh → Second-stage grinding 50-60 mesh, final particle size 0.25-0.35mm;

[0033] Camphor branches: First-stage crushing 8-12 mesh → Second-stage crushing 40-50 mesh, final particle size 0.35-0.45mm;

[0034] Dried camphor trees: First-stage grinding to 5-10 mesh → Second-stage grinding to 30-40 mesh, final particle size 0.45-0.6mm;

[0035] (3) Low-temperature plasma pretreatment: Optimize process parameters according to the characteristics of different raw materials to enhance the cell wall disruption effect:

[0036] Leaf raw material: Argon flow rate 18-20L / min, discharge power 350-400W, processing time 8-10 minutes;

[0037] Raw material for the branch: Argon flow rate 16-18L / min, discharge power 320-350W, processing time 10-12 minutes;

[0038] Dry raw materials: Argon flow rate 15-16L / min, discharge power 300-320W, processing time 12-15 minutes;

[0039] (4) Microwave-assisted activation: Precise control of microwave parameters avoids overheating damage to raw materials and further improves the release efficiency of essential oils.

[0040] Leaf raw material: power 550-600W, temperature 65-70℃, processing time 5-6 minutes;

[0041] Raw material: Power 520-550W, temperature 62-65℃, processing time 6-7 minutes;

[0042] Dry raw materials: power 500-520W, temperature 60-62℃, processing time 7-8 minutes.

[0043] The cryogenic plasma pretreatment chamber includes a chamber body 33. An argon inlet 34 is located on the top left side of the chamber body 33, and a flow regulating valve 35 is installed on the argon inlet 34. A plasma generator 36 is arranged horizontally inside the chamber body 33. The discharge electrodes 37 of the plasma generator 36 include needle electrodes 38 and plate electrodes 39. The needle electrodes 38 are arranged in an array. A conveyor 40 is set inside the chamber body 33, and openings are set at both ends extending out of the area of ​​the chamber body 33. Rubber strips are installed at the openings and attached to the sides of the conveyor 40. When not turned outward, they can prevent the argon gas inside the chamber body 33 from being discharged. The raw material outlet 42 is located on the bottom right side of the chamber body 33. An inclined guide plate is set inside the chamber body 33 at the location corresponding to the raw material outlet 42. The inclined guide plate is attached to the conveyor belt of the conveyor 40. When the conveyor 40 continues to convey to the right, the raw material is discharged to the raw material outlet through the inclined guide plate. The raw material outlet 42 can be fixed to its outer port with a sealing plate screw with a ring-shaped rubber seal, so that argon gas will not be discharged from the raw material outlet 42 during the process. A guide trough 43 is installed at the raw material outlet 42. The exhaust port 44 is located on the top right side of the chamber 33 and is connected to the activated carbon filter 45 through an air pump.

[0044] The power input terminal of the plasma generator 36 is connected to the power analog output terminal of the frequency converter via a cable. The main power supply of the frequency converter is connected to the external power supply. The power control terminal of the conveyor 40 is connected to the power control output terminal of the driver via a cable. The main power input terminal of the driver is connected to the external power supply. The signal input terminals of the frequency converter and the driver are connected to the signal input terminal of the external computer via a signal connection. The frequency converter control program and the driver control program are loaded in the external computer.

[0045] Cabin 33 dimensions: 1200mm long × 800mm wide × 600mm high, material: 316L stainless steel, wall thickness: 8mm, design pressure: 0.1MPa;

[0046] Argon inlet 34: 25mm in diameter, equipped with a flow regulating valve with an adjustment range of 0-50L / min and an accuracy of ±0.1L / min;

[0047] Plasma generator 36: power adjustable range 0-500W, frequency 13.56MHz, discharge electrode is needle plate type;

[0048] The needle electrodes consist of 12 pieces, made of tungsten alloy, with a diameter of 3mm, a length of 150mm, a spacing of 6cm, and arranged in a 2×6 array.

[0049] Plate electrode 39: Dimensions 1000mm×600mm×5mm, material stainless steel, grounded;

[0050] Conveyor 40: Width 600mm, material PTFE, speed 0.5-1m / min, load capacity ≤50kg / m;

[0051] Raw material outlet 42: 300mm in diameter, with a guide chute installed at a 30° inclination angle;

[0052] Exhaust port 44: diameter 50mm; activated carbon filter 45 adsorption capacity ≥5kg, filtration efficiency ≥95%.

[0053] Step 2: Three-stage countercurrent steam distillation. The raw material processed in Step 1 is subjected to three-stage countercurrent steam distillation using a three-stage countercurrent distillation column, and a gradient temperature and pressure system is used for control.

[0054] Three-stage countercurrent steam distillation

[0055] (1) Charging parameters: Optimize the charging process based on the density difference of the raw materials to ensure uniform steam mass transfer:

[0056] Leaf feedstock: packing density 0.38-0.4 g / cm³, with each stage packing amounting to 68%-70% of the tower volume;

[0057] Raw material: packing density 0.36-0.38 g / cm³, with each stage packing amounting to 66%-68% of the tower volume;

[0058] Dry raw materials: packing density 0.35-0.36 g / cm³, with each stage packing amount being 65%-66% of the tower volume;

[0059] (2) Steam preparation: A saturated steam generator with a volume of 500L and a working pressure of 0.3MPa is used to generate saturated steam with a pressure of 0.12-0.15MPa and a temperature of 105-110℃. The steam is then uniformly introduced into the distillation space through a steam distributor with a hole diameter of 2mm and a hole spacing of 10mm.

[0060] (3) Fractional distillation: A gradient temperature-pressure system is used to adapt to the essential oil release characteristics of different raw materials. The specific parameters are shown in the table below:

[0061] Raw material type First-stage distillation (feed section) Two-stage distillation (mass transfer section) Third-stage distillation (depth range) Total distillation time leaf 96-92℃ / 0.09-0.1MPa / 20-22 minutes 90-92℃ / 0.07-0.08MPa / 15-17 minutes 83-85℃ / 0.05-0.06MPa / 10-12 minutes 45-51 minutes branch 95-97℃ / 0.085-0.095MPa / 22-24 minutes 89-91℃ / 0.065-0.075MPa / 17-19 minutes 82-84℃ / 0.045-0.055MPa / 12-14 minutes 51-57 minutes Dry 94-96℃ / 0.08-0.09MPa / 24-25 minutes 88-90℃ / 0.06-0.07MPa / 19-20 minutes 81-83℃ / 0.04-0.05MPa / 14-15 minutes 57-60 minutes

[0062] (4) Steam flow: A Z-shaped flow loop 10 is adopted, which is composed of a guide plate 11. The guide plate 11 is made of 316L stainless steel with a thickness of 3mm and a length of 600mm. The arrangement angle of the guide plate 11 is 45° and the arrangement spacing is 150mm. The steam flow rate is controlled at 0.8-1.2m / s to extend the contact time between the steam and the raw materials and improve the mass transfer efficiency.

[0063] The overall dimensions of the three-stage countercurrent distillation column are: diameter 800mm, total height 3000mm, wall thickness 10mm, and material 304 stainless steel. The column includes a column body 6, with a heat source chamber 22 located at the center of the column body 6, having a diameter of 200mm and a height of 2800mm. The heat source chamber 22 houses an electric heater 23, which is 15kW in power. An electric heater with a heating efficiency ≥90% is provided. The power cord of the electric heater 23 is connected to the power output terminal of the temperature controller, and the main power cord of the temperature controller is connected to an external power source. Three-stage distillation spaces 9 are stacked around the heat source chamber 22, each stage with a height of 800mm and a volume of 0.402m³. The side wall of the lowest distillation space 9 has a discharge port, on which a sliding seal is installed for discharging the raw material from the distillation space 9. When the sliding seal closes the discharge port, it effectively reduces the amount of steam discharged. The spacing between adjacent distillation spaces 9 is 100mm, and adjacent distillation spaces 9 are connected by four evenly distributed passages 24, each passage 24 with a diameter of 100mm. A one-way valve 25 with an opening pressure of 0.01MPa is installed on each passage 24. A Z-shaped flow loop 10 is provided in each distillation space. Inside the first-stage distillation space 9, a flow-bending channel is formed by guide plates 11 with a spacing of 150mm. The steam distributor 8 is located at the bottom of the three-stage countercurrent distillation column, with an overall diameter of 700mm. It includes a multi-hole nozzle 26 with a hole diameter of 2mm, a hole spacing of 10mm, a total of 320 holes, and a steam injection angle of 45°. The condensing surface 27 is a mesh structure made of 304 stainless steel with a hole diameter of 0.5mm, a mesh density of 60 mesh, and an area of ​​1.5 square meters. It is set on the inner wall of the distillation space 9. The raw material inlet 29 is located on the sealing cover 30 with a diameter of 200mm and a rubber sealing ring with a thickness of 5mm installed at the top of the first-stage distillation space 9. The steam outlet 32 ​​is located at the top of the third-stage distillation space 9 with a diameter of 100mm and is used to connect to the composite condensation system 46.

[0064] When in use, the three-stage countercurrent distillation column is hoisted onto the steam boiler using hoisting equipment.

[0065] Step 3: Composite condensation and recovery. The camphor oil primary product obtained in Step 2 is recovered through a composite condensation and recovery system, which is a serpentine condenser 12 and a plate condenser 13 connected in series.

[0066] The composite condensation recovery system includes a serpentine condenser 12, a compressor, a plate condenser 13 connected to the exhaust pipe of the serpentine condenser 12, and a mixed liquid collection tank 52 connected to the plate condenser 13. A steam inlet 55 is located on the upper side of the serpentine condenser 12 and connected to the exhaust pipe of the compressor. A cooling water inlet 48 is located at the bottom of the serpentine condenser 12 and is equipped with a thermometer 49. A cooling water outlet 50 is located at the bottom of the plate condenser 13 and is equipped with a flow meter 51. A level gauge 53 and a temperature sensor 54 are installed in the mixed liquid collection tank 52. The compressor inlet is connected to the steam outlet 32 ​​and is equipped with a pressure sensor 56. A condensate outlet 57 is located at the bottom of the mixed liquid collection tank 52 and is connected to a centrifugal oil-water separator 14.

[0067] (1) Primary condensation: A serpentine condenser 12 is used, with a tube diameter of 50mm, a wall thickness of 3mm, a total length of 15m, a coil diameter of 300mm, and a spacing of 50mm. The cooling water temperature is controlled at 15-20℃, and the condensation rate is 1.8-2L / min.

[0068] (2) Secondary condensation: 13 plate condensers in series, with plate size of 800mm×400mm×1.5mm, 20 plates, plate spacing of 8mm, and condensation area of ​​5m², to reduce the condensation temperature to 5-8℃ and enhance the condensation effect of essential oils;

[0069] (3) Oil-water separation: A centrifugal oil-water separator 14 made of titanium alloy is used, with a rotation speed of 3200-3500 rpm and a separation time of 12-15 minutes to improve the purity of oil-water separation;

[0070] The serpentine condenser is made of 304 stainless steel, and the internal serpentine coil is installed at a 15° angle inside the condenser.

[0071] Cooling water inlet 48, diameter 40mm; thermometer 49, range 0-50℃, accuracy ±0.1℃;

[0072] Cooling water outlet 50, diameter 40mm; flow meter 51, range 0-5L / min, accuracy ±0.01L / min;

[0073] The mixed liquid collection tank 52 has a volume of 50L, a diameter of 300mm, a height of 700mm, and is made of 304 stainless steel. The level gauge 53 has a range of 0-50L and an accuracy of ±0.1L. The temperature sensor 54 is a PT100 type temperature sensor.

[0074] Steam inlet 55, diameter 100mm; Pressure sensor 56, range 0-0.2MPa, accuracy ±0.001MPa;

[0075] The condensate outlet is 57 with a diameter of 50 mm.

[0076] Step 4: Refining and purification; the refining and purification steps include:

[0077] Step 1.1: Add the oil treated by the centrifugal oil-water separator 14 to the drying tank for drying and dehydration. The amount of anhydrous sodium sulfate added is: 6%-8% of camphor leaves, 7%-8% of camphor branches, and 8%-10% of dried camphor. Let it stand for 2.5-3 hours to remove moisture. Then, sieve the oil through a molecular sieve device to obtain the third-grade essential oil.

[0078] Step 1.2: Add the tertiary essential oil obtained in Step 1.1 to a molecular still for distillation. The distillation column of the molecular still has a diameter of 300 mm and a height of 1200 mm. The temperature is 65-70℃ for camphor leaves, 68-72℃ for camphor branches, and 70-75℃ for dried camphor. The pressure is 5-8 Pa. Separate impurities to obtain secondary essential oil.

[0079] Step 1.3: The secondary essential oil obtained in Step 1.2 is added to a silica gel column chromatography eluting machine for elution. The silica gel column of the eluting machine has a diameter of 80 mm and a column height of 1200 mm. The eluents used are petroleum ether and ethyl acetate, with a volume ratio of petroleum ether to ethyl acetate of 1:9. The elution flow rate is 5-8 mL / min to further improve the purity of the essential oil.

[0080] Example 1 (Dried camphor leaf raw material)

[0081] (1) Raw materials

[0082] Fresh camphor leaves, with a moisture content of 13%, free from mold, pests, and impurities;

[0083] (2) Pretreatment

[0084] First-stage grinding (12 mesh) → Second-stage grinding (55 mesh), final particle size 0.3 mm; Plasma treatment: argon flow rate 19 L / min, discharge power 380 W, treatment time 9 minutes; Microwave activation: power 580 W, temperature 68 °C, treatment time 5.5 minutes;

[0085] (3) Distillation

[0086] The packing density was 0.39 g / cm³, the first-stage distillation parameters were 97℃ / 0.095 MPa / 21 min, the second-stage distillation parameters were 91℃ / 0.075 MPa / 16 min, the third-stage distillation parameters were 84℃ / 0.055 MPa / 11 min, and the total distillation time was 48 min.

[0087] (4) Condensation

[0088] Serpentine condenser: cooling water temperature 18℃; Plate condenser: condensation temperature 6℃, condensation rate 1.9L / min;

[0089] (5) Separation and purification

[0090] Centrifugation: 3300 rpm, separation time 13 minutes; anhydrous sodium sulfate added 7%, allowed to stand for 2.8 hours; Molecular distillation: temperature 68℃, pressure 6 Pa; Column chromatography: elution flow rate 6 mL / min;

[0091] (6) Results

[0092] The yield of camphor oil is 4.6%, the energy consumption per ton of raw material is 275 kWh, the purity of essential oil is 98.5%, including camphor content of 43.2%, eucalyptol content of 33.1%, and linalool content of 8.7%.

[0093] Example 2 (Dried camphor branch raw material)

[0094] (1) Raw materials

[0095] Dried camphor branches, with a moisture content of 15%, are peeled and impurities are removed.

[0096] (2) Pretreatment

[0097] First-stage grinding (10 mesh) → Second-stage grinding (45 mesh), final particle size 0.4 mm; Plasma treatment: argon flow rate 17 L / min, discharge power 330 W, treatment time 11 minutes; Microwave activation: power 530 W, temperature 63 °C, treatment time 6.5 minutes;

[0098] (3) Distillation

[0099] The packing density was 0.37 g / cm³, the first-stage distillation parameters were 96℃ / 0.09 MPa / 23 min, the second-stage distillation parameters were 90℃ / 0.07 MPa / 18 min, the third-stage distillation parameters were 83℃ / 0.05 MPa / 13 min, and the total distillation time was 54 min.

[0100] (4) Condensation

[0101] Serpentine condenser: cooling water temperature 19℃; Plate condenser: condensation temperature 7℃, condensation rate 1.85L / min;

[0102] (5) Separation and purification

[0103] Centrifugation: 3400 rpm, separation time 14 minutes; anhydrous sodium sulfate addition 7.5%, standing for 2.9 hours; Molecular distillation: temperature 70℃, pressure 7 Pa; Column chromatography: elution flow rate 7 mL / min;

[0104] (6) Results

[0105] The yield of camphor oil is 4.0%, the energy consumption per ton of raw material is 285 kWh, the purity of essential oil is 98.2%, including camphor content of 45.6%, eucalyptol content of 30.8%, and linalool content of 7.3%.

[0106] Example 3 (Peeled dried camphor tree material)

[0107] (1) Raw materials

[0108] Barkless dried camphor tree, moisture content 17%, free of rotten parts and impurities;

[0109] (2) Pretreatment

[0110] First-stage grinding to 8 mesh → second-stage grinding to 35 mesh, final particle size 0.5 mm; plasma treatment: argon flow rate 15.5 L / min, discharge power 310 W, treatment time 13 minutes; microwave activation: power 510 W, temperature 61 ℃, treatment time 7.5 minutes;

[0111] (3) Distillation

[0112] The packing density is 0.355 g / cm³, the first-stage distillation parameters are 95℃ / 0.085 MPa / 24.5 min, the second-stage distillation parameters are 89℃ / 0.065 MPa / 19.5 min, the third-stage distillation parameters are 82℃ / 0.045 MPa / 14.5 min, and the total distillation time is 58.5 min.

[0113] (4) Condensation

[0114] Serpentine condenser: cooling water temperature 20℃; Plate condenser: condensation temperature 8℃, condensation rate 1.8L / min;

[0115] (5) Separation and purification

[0116] Centrifugation: 3500 rpm, separation time 15 minutes; anhydrous sodium sulfate added 9%, stand for 3 hours; Molecular distillation: temperature 72℃, pressure 8 Pa; Column chromatography: elution flow rate 8 mL / min;

[0117] (6) Results

[0118] The yield of camphor oil is 3.7%, the energy consumption per ton of raw material is 295 kWh, the purity of essential oil is 98.0%, including camphor content of 48.3%, eucalyptol content of 28.5%, and linalool content of 6.1%.

[0119] Comparative Example 1 (Traditional direct steam distillation - leaf feedstock, CN113150873A process)

[0120] (1) Raw materials: Same as in Example 1;

[0121] (2) Pretreatment: Grind to 30 mesh, without plasma or microwave treatment;

[0122] (3) Distillation: A single-stage direct steam distillation pot with a diameter of 1200 mm and a height of 2000 mm was used. The distillation parameters were 98℃ / 0.1 MPa and the distillation time was 90 minutes.

[0123] (4) Condensation: Single serpentine condenser, pipe diameter 40mm, length 10m, cooling water temperature 25℃;

[0124] (5) Results: The yield of camphor oil was 1.85%, the extraction time was 90 minutes, the unit energy consumption was 410 kWh / ton of raw material, the purity of essential oil was 92.4%, of which the content of eucalyptol was 28.3% and the content of camphor was 40.1%.

[0125] Comparative Example 2 (MAHD Microwave-Assisted Process - Leaf Raw Material)

[0126] (1) Raw materials: Same as in Example 1;

[0127] (2) Pretreatment: Grind to 40 mesh, microwave treatment: power 786W, treatment time 35 minutes;

[0128] (3) Distillation: A single-stage steam distillation pot with a diameter of 1000 mm and a height of 1800 mm was used. The distillation parameters were 95℃ / 0.08MPa and the distillation time was 60 minutes.

[0129] (4) Condensation: Single serpentine condenser, pipe diameter 45mm, length 12m, cooling water temperature 20℃;

[0130] (5) Results: The yield of camphor oil was 3.26%, the extraction time was 60 minutes, the unit energy consumption was 360 kWh / ton of raw material, the purity of essential oil was 95.7%, of which the content of eucalyptol was 30.5% and the content of camphor was 42.8%.

[0131] Comparative Example 3 (Traditional Process - Mixed Branches / Trees)

[0132] (1) Raw materials: dried camphor branches + peeled camphor wood, mass ratio 1:1, moisture content 16%;

[0133] (2) Pretreatment: Grind to 30 mesh, without plasma or microwave treatment;

[0134] (3) Distillation: Single-stage direct steam distillation, distillation parameters 99℃ / 0.105MPa, distillation time 120 minutes;

[0135] (4) Condensation: Single serpentine condenser, cooling water temperature 28℃;

[0136] (5) Results: The yield of camphor oil was 1.62%, the extraction time was 120 minutes, the unit energy consumption was 430 kWh / ton of raw material, the purity of essential oil was 91.8%, of which the content of eucalyptol was 26.7% and the content of camphor was 44.2%.

[0137] See the table below for detailed comparison results:

[0138] Comparison items Traditional direct steam distillation (leaf) Traditional direct steam distillation (branch / dried mixture) MAHD Microwave-Assisted Process (Ye) The process of this invention (leaf) The process (branch) of this invention The process of this invention (dry) Improvement of this invention vs. traditional (leaf) Camphor oil yield (%) 1.76-2.025 1.5-1.7 3.26±0.05 4.2-4.8 3.8-4.1 3.5-3.8 +106%-135% Extraction time (minutes) 90-120 120-150 60 45-51 51-57 57-60 -33%-50% Essential oil purity (%) 90-93 89-92 95-96 ≥98.2 ≥98.0 ≥97.8 +5%-8% Eucalyptol retention rate (%) 75-80 70-75 85-90 95-98 93-96 90-93 +15%-23% Camphor content (%) 40-42 43-45 42-44 43-45 45-47 48-50 +2.5%-7.1% Preprocessing methods Simple crushing Simple crushing Microwave processing Plasma + Microwave Synergy (Ye Exclusive) Plasma + Microwave Synergy (Exclusive to Branch) Plasma + Microwave Synergy (Dry-Specific) Structural innovation + raw material adaptation distillation stages Level 1 Level 1 Level 1 Level 3 countercurrent (blade parameter) Level 3 countercurrent (branch parameter) Level 3 countercurrent (dry parameter) Process innovation + parameter adaptation Condensation method Single condenser (40mm diameter, 10m length) Single condenser (40mm diameter, 10m length) Single condenser (pipe diameter 45mm, length 12m) Composite condenser (50mm diameter, 15m length + 5m² plate cooler) Composite condensation (same as left) Composite condensation (same as left) Equipment innovation + size optimization

[0139] As shown in the table above, the pretreatment synergy is the first to optimize the low-temperature plasma-microwave synergistic pretreatment parameters for different raw materials such as leaves, branches and trunks, so that the cell wall damage rate reaches 90% for camphor leaves, 88% for camphor branches and 85% for camphor trunks, effectively solving the technical problem of high steam mass transfer resistance in traditional pretreatment processes.

[0140] Multi-stage countercurrent distillation: Employing a three-stage gradient temperature-pressure distillation system, it precisely adapts to the essential oil release characteristics of different raw materials, increasing steam utilization by 45% compared to traditional single-stage distillation;

[0141] Composite condensation recovery system: It adopts a series structure of serpentine condenser and plate condenser with a condensation area of ​​5 square meters, which reduces the essential oil evaporation loss rate to 3%-5%, which is significantly better than the traditional single condensation process;

[0142] Multi-raw material compatibility: By optimizing the particle size, pretreatment parameters, and distillation conditions, efficient extraction of camphor leaves, branches, and trunks is achieved, solving the problem of large fluctuations in the extraction yield of mixed raw materials in traditional processes.

[0143] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention.

Claims

1. A high-efficiency extraction process for camphor oil based on steam distillation, characterized in that, Includes the following steps: Step 1: Raw material pretreatment. The raw materials are crushed and then subjected to low-temperature plasma treatment in a low-temperature plasma pretreatment chamber. The raw materials that have undergone low-temperature plasma treatment are then activated by microwave activation equipment. Step 2: Three-stage countercurrent steam distillation. The raw material processed in Step 1 is subjected to three-stage countercurrent steam distillation using a three-stage countercurrent distillation column, and a gradient temperature and pressure system is used for control. Step 3: Composite condensation and recovery. The camphor oil primary product obtained in Step 2 is recovered through a composite condensation and recovery system. The composite condensation and recovery system is a series structure of a serpentine condenser (12) and a plate condenser (13). Step 4: Refining and purification. First, the product is dried and dehydrated, then finely distilled, and finally eluted.

2. The high-efficiency extraction process of camphor oil based on steam distillation according to claim 1, characterized in that, In step one, the particle size of the raw materials after being pulverized by a two-stage pulverizer is: camphor leaves 0.25-0.35mm, camphor branches 0.35-0.45mm, and camphor trunks 0.45-0.6mm; the low-temperature plasma treatment parameters are: Camphor leaves: Argon flow rate 18-20L / min, discharge power 350-400W, treatment time 8-10 minutes; Camphor branches: Argon flow rate 16-18L / min, discharge power 320-350W, processing time 10-12 minutes; Dry camphor trees: Argon flow rate 15-16L / min, discharge power 300-320W, processing time 12-15 minutes.

3. The high-efficiency extraction process of camphor oil based on steam distillation according to claim 2, characterized in that, The microwave-assisted activation parameters are: Camphor leaves: Power 550-600W, temperature 65-70℃, processing time 5-6 minutes; Camphor branches: Power 520-550W, temperature 62-65℃, processing time 6-7 minutes; Camphor tree drying: power 500-520W, temperature 60-62℃, processing time 7-8 minutes.

4. The high-efficiency extraction process of camphor oil based on steam distillation according to claim 3, characterized in that, The packing density of the three-stage countercurrent steam distillation is as follows: camphor leaves 0.38-0.4 g / cm³, camphor branches 0.36-0.38 g / cm³, and dried camphor 0.35-0.36 g / cm³, with each stage filling 65%-70% of the volume.

5. The high-efficiency extraction process of camphor oil based on steam distillation according to claim 4, characterized in that, The temperature gradient and pressure gradient of the three-stage countercurrent steam distillation are: Camphor leaves: Grade 1: 96-98℃ / 0.09-0.1MPa; Grade 2: 90-92℃ / 0.07-0.08MPa; Grade 3: 83-85℃ / 0.05-0.06MPa; Camphor tree branches: Grade 1: 95-97℃ / 0.085-0.095MPa; Grade 2: 89-91℃ / 0.065-0.075MPa; Grade 3: 82-84℃ / 0.045-0.055MPa. Camphor tree bark: Grade 1: 94-96℃ / 0.08-0.09MPa; Grade 2: 88-90℃ / 0.06-0.07MPa; Grade 3: 81-83℃ / 0.04-0.05MPa. Total distillation time: 45-60 minutes.

6. The high-efficiency extraction process of camphor oil based on steam distillation according to claim 5, characterized in that, The refining and purification steps include: Step 1.1: Add the oil treated by the centrifugal oil-water separator (14) to the drying tank for drying and dehydration. The amount of anhydrous sodium sulfate added is: 6%-8% of camphor leaves, 7%-8% of camphor branches, and 8%-10% of dried camphor. Let it stand for 2.5-3 hours, and then screen out the third grade essential oil through a molecular sieve device. Step 1.2: Add the tertiary essential oil obtained in Step 1.1 to a molecular still for fine distillation. The distillation column of the molecular still has a diameter of 300 mm and a height of 1200 mm. The temperature is 65-70℃ for camphor leaves, 68-72℃ for camphor branches, and 70-75℃ for dried camphor. The pressure is 5-8 Pa to obtain the secondary essential oil. Step 1.3: The secondary essential oil obtained in Step 1.2 is added to a silica gel column chromatography eluting machine for elution. The silica gel column of the eluting machine has a diameter of 80 mm and a column height of 1200 mm. The eluents used are petroleum ether and ethyl acetate, with a volume ratio of petroleum ether to ethyl acetate of 1:9 and an elution flow rate of 5-8 mL / min.

7. The high-efficiency extraction process for camphor oil based on steam distillation according to any one of claims 1-6, characterized in that, The low-temperature plasma pretreatment chamber includes a chamber body (33), an argon gas inlet (34) located on the top left side of the chamber body (33), and a flow regulating valve (35) installed on the argon gas inlet (34); a plasma generator (36) is arranged horizontally inside the chamber body (33), and the discharge electrodes (37) of the plasma generator (36) include needle electrodes (38) and plate electrodes (39), with the needle electrodes (38) arranged in an array, and a conveyor (40) installed in the chamber body (33); a raw material outlet (42) is located on the bottom right side of the chamber body (33), and a guide trough (43) is installed; an exhaust port (44) is located on the top right side of the chamber body (33), and is connected to an activated carbon filter (45) via a vacuum pump.

8. The high-efficiency extraction process for camphor oil based on steam distillation according to any one of claims 1-6, characterized in that, The three-stage countercurrent distillation column includes a column body (6), a heat source chamber (22) located at the center of the column body (6), an electric heater (23) built into the heat source chamber (22), and three-stage distillation spaces (9) stacked around the heat source chamber (22). Adjacent distillation spaces (9) are connected by a passage (24), and a one-way valve (25) is installed on the passage (24). A Z-shaped flow loop (10) is set in each distillation space (9), which is formed by a baffle plate (11) with a spacing of 150 mm between the baffle plates (11). A steam distributor (8) is located at the bottom of the three-stage countercurrent distillation column and includes a multi-hole nozzle (26). The condensation surface (27) is a mesh structure and is set on the inner wall of the distillation space (9). The raw material inlet (29) is located on the sealing cover (30) installed at the top of the first-stage distillation space (9). The steam outlet (32) is located at the top of the three-stage distillation space (9) and is used to connect to the composite condensation recovery system.

9. The high-efficiency extraction process for camphor oil based on steam distillation according to any one of claims 1-6, characterized in that, The composite condensation recovery system includes a serpentine condenser (12), a compressor, a plate condenser (13) connected to the exhaust pipe of the serpentine condenser (12), and a mixed liquid collection tank (52) connected to the pipe of the plate condenser (13). A steam inlet (55) is located on the upper side of the serpentine condenser (12) and connected to the exhaust pipe of the compressor. A cooling water inlet (48) is located at the bottom of the serpentine condenser (12) and a thermometer (49) is installed thereon. A cooling water outlet (50) is located at the bottom of the plate condenser (13) and a flow meter (51) is installed thereon. A level gauge (53) and a temperature sensor (54) are installed in the mixed liquid collection tank (52). The compressor inlet is connected to the steam outlet (32) and a pressure sensor (56) is installed thereon. A condensate outlet (57) is located at the bottom of the mixed liquid collection tank (52) and connected to a centrifugal oil-water separator (14).

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