Low-energy consumption hempseed oil ultra-short time low-temperature deodorization method

Abstract

The application belongs to the technical field of oil refining processing, and provides a low-energy consumption hempseed oil ultra-short-time low-temperature deodorization method.The hempseed oil decolorized oil after degumming, deacidification and decolorization treatment is sequentially subjected to spray gas stripping deoxygenation, spray nitrogen replacement deoxygenation, low-temperature thin-layer circulating nitrogen stripping deoxygenation and partition spray low-temperature deodorization, and is cooled under vacuum or nitrogen protection to obtain finished hempseed oil.The hempseed oil decolorized oil can also be pre-conditioned at low temperature by a food-grade adsorption medium fixed bed before deodorization, the circulating nitrogen is reused after being condensed to remove liquid, dried and deodorized, and the partition deodorization volatiles are separately condensed and captured.The method reduces residual oxygen and moisture before entering the tower, controls the mass transfer and heat history in the deodorization section, reduces the oxidation and hydrolysis risk under the condition of a large interface of spraying, takes into account the removal of odor components and the retention of heat-sensitive nutrients, and is suitable for continuous refining processing of high-unsaturated hempseed oil.

Description

Technical Field

[0001] This invention belongs to the field of oil refining and processing technology, and relates to a low-energy-consumption method for ultra-short-time low-temperature deodorization of hemp seed oil. Background Technology

[0002] Existing oil deodorization processes mostly rely on heating, vacuum, and stripping media to remove odor components through volatilization. For common vegetable oils, increasing the deodorization temperature, extending the stripping time, or enhancing vacuum conditions can improve the removal of odor components. However, hemp seed oil has a high content of unsaturated fatty acids, and the oil phase is sensitive to oxygen and moisture under heating conditions. Excessive thermal processes can easily cause oxidation, hydrolysis, and loss of heat-sensitive components. Therefore, directly applying conventional oil deodorization methods to hemp seed oil can easily create a contradiction between sufficient deodorization and quality maintenance.

[0003] To reduce heat damage, existing technologies employ deodorization approaches using low temperatures, high vacuum, or short processing times. These processes mitigate the thermal impact on unsaturated fatty acids and heat-sensitive nutrients in hemp seed oil by lowering the operating temperature. However, at lower temperatures, the volatilization driving force of odor components such as aldehydes, ketones, and lower carboxylic acids decreases, and the contact efficiency between the oil and the vacuum environment or stripping medium becomes a significant factor limiting the deodorization effect. Simply shortening the heat residence time without simultaneously enhancing mass transfer can easily lead to insufficient removal of odor components.

[0004] To improve deodorization efficiency under low-temperature conditions, the contact interface between the oil and the gas phase can be increased through methods such as spraying, film extraction, falling film extraction, or stripping enhancement, thus shortening the migration path of off-odor components from the oil phase to the gas phase. However, under these large interfacial conditions, hemp seed oil is also more easily exposed to the reaction environment formed by residual dissolved oxygen and trace amounts of moisture. Residual dissolved oxygen in the oil may participate in the oxidation of unsaturated fatty acids under heating and large interfacial contact conditions, while trace amounts of moisture may participate in the hydrolysis of glycerides. Both of these factors weaken the effect of low-temperature deodorization on quality maintenance and affect the flavor stability and nutrient retention of hemp seed oil.

[0005] Therefore, the existing low-temperature deodorization process for hemp seed oil still has the following problems: In order to remove odor components such as aldehydes, ketones, and lower carboxylic acids at lower temperatures, it is necessary to improve the contact efficiency between the oil and the vacuum environment or stripping medium; however, hemp seed oil is rich in polyunsaturated fatty acids, and residual dissolved oxygen and trace amounts of water in the oil are easily involved in oxidation and hydrolysis processes under heating and large interface contact conditions, making it difficult to simultaneously remove odor components, inhibit oxidation side reactions, and retain heat-sensitive nutrients during the low-temperature deodorization process. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a low-energy-consumption, ultra-short-time, low-temperature deodorization method for hemp seed oil. This method involves sequentially subjecting the decolorized hemp seed oil to spray gas evolution deoxygenation, spray nitrogen replacement deoxygenation, low-temperature thin-layer circulating nitrogen stripping deoxygenation, and dual-zone spray low-temperature deodorization, while also performing zoned condensation and collection of volatiles. This method improves the mass transfer removal efficiency of odor components while reducing the risk of oxidation and hydrolysis caused by residual oxygen and moisture, thereby enhancing the deodorization quality of hemp seed oil.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a low-energy-consumption method for ultra-short-time low-temperature deodorization of hemp seed oil, comprising the following steps:

[0009] S1, the decolorized hemp seed oil after degumming, deacidification and decolorization is sent to the first-stage spray gas deoxygenation device, nitrogen is introduced, and the decolorized hemp seed oil is atomized into oil droplets under vacuum spraying conditions and subjected to first-stage spray gas deoxygenation to obtain first-stage deoxygenated oil.

[0010] S2, the primary deoxygenated oil is sent to the secondary spray nitrogen replacement deoxygenation device, nitrogen is introduced, and the primary deoxygenated oil is atomized into oil droplets under vacuum spray conditions and then subjected to secondary spray nitrogen replacement deoxygenation to obtain secondary deoxygenated oil.

[0011] S3, the secondary deoxygenated oil is sent into the low-temperature thin-layer circulating nitrogen deoxygenation unit, spread into a thin-layer oil film, and then deoxygenated by countercurrent contact with purified circulating nitrogen to obtain thin-layer deoxygenated oil.

[0012] S4, the thin-layer deoxygenated oil is fed into a dual-zone spray-type low-temperature deodorization device, and is spray-deodorized sequentially through a front spray deodorization zone and a rear spray deodorization zone. The temperature of the rear spray deodorization zone is higher than that of the front spray deodorization zone, and the absolute pressure of the rear spray deodorization zone is lower than that of the front spray deodorization zone. The volatiles discharged from the front spray deodorization zone and the rear spray deodorization zone are condensed and collected to obtain deodorized oil.

[0013] S5, the deodorized oil is cooled under vacuum or nitrogen protection to obtain the finished hemp seed oil.

[0014] Preferably, in S1, the moisture content of the decolorized hemp seed oil is not higher than 0.10 wt.%, the absolute pressure in the primary spray deoxygenation device is 1-5 kPa, the temperature is 60-85℃, the primary spray deoxygenation time is 4-12 min, and the water-containing gas phase discharged from the primary spray deoxygenation device is extracted by the vacuum system of the primary spray deoxygenation device after condensation and liquid removal.

[0015] Preferably, in S2, the absolute pressure inside the secondary spray nitrogen replacement deoxygenation device is 0.5-3 kPa, the temperature is 70-95℃, and the secondary spray nitrogen replacement deoxygenation time is 2-8 min.

[0016] Preferably, in S1 and S2, the oil droplet size in the primary spray deoxygenation and the secondary spray nitrogen replacement deoxygenation is 10-80 μm, and the purity of the nitrogen is not less than 99.99%.

[0017] Preferably, in S3, the low-temperature thin-film circulating nitrogen deoxygenation unit is a falling film degasser, a scraped film evaporator, or a centrifugal thin-film evaporator, and the thickness of the thin oil film is 0.1-0.8 mm.

[0018] Preferably, in S3, the temperature of the low-temperature thin-layer circulating nitrogen deoxygenation unit is 80-100℃, the absolute pressure is 0.3-2kPa, and the thin-layer deoxygenation time is 0.5-5min.

[0019] Preferably, in S3, after the circulating nitrogen is discharged from the low-temperature thin-layer circulating nitrogen deoxygenation unit, it is processed sequentially through the condensation and dehydration unit, the drying unit, and the deodorization unit before returning to the low-temperature thin-layer circulating nitrogen deoxygenation unit. By partially discharging and replenishing high-purity nitrogen with a purity of not less than 99.99%, the oxygen content in the recycled nitrogen is controlled to be no higher than 50 ppmv.

[0020] Preferably, the condensation and deliquescence unit uses indirect heat exchange to condense the gas to be treated. The cooling medium is circulating cooling water, ethylene glycol aqueous solution, or refrigerant. The cooling medium does not directly contact the gas to be treated. Water vapor, entrained oil mist, and condensable volatiles in the gas to be treated are condensed into a liquid phase and discharged after gas-liquid separation. The separated gas enters the vacuum system or a subsequent drying unit.

[0021] Preferably, the drying unit is filled with 3A molecular sieve, 4A molecular sieve or silica gel desiccant, and the deodorizing unit is filled with food-grade activated carbon.

[0022] Preferably, the circulating nitrogen gas is further processed by a deoxidation unit before returning to the low-temperature thin-layer circulating nitrogen deoxidation unit, and the deoxidation unit is filled with a reduced copper-based deoxidizer.

[0023] Preferably, in S4, the temperature of the front spray deodorization zone is 90-115℃, the absolute pressure is 100-500Pa, and the residence time is 0.5-3min; the temperature of the rear spray deodorization zone is 115-135℃, the absolute pressure is 20-80Pa, and the residence time is 1-5min.

[0024] Preferably, in S4, both the front spray deodorization zone and the rear spray deodorization zone use nitrogen as the atomizing medium and stripping gas; the nitrogen is preheated to 5-25°C higher than the oil temperature of the front spray deodorization zone before entering the front spray deodorization zone, and the nitrogen is preheated to 5-25°C higher than the oil temperature of the rear spray deodorization zone before entering the rear spray deodorization zone.

[0025] Preferably, in S4, the volatiles discharged from the front spray deodorization zone are collected by the first condensation and collection unit, and the volatiles discharged from the rear spray deodorization zone are collected by the second condensation and collection unit. The condensation temperature of the first condensation and collection unit is -5°C to 10°C, and the condensation temperature of the second condensation and collection unit is -40°C to -10°C.

[0026] Preferably, before S1, the process further includes subjecting the decolorized hemp seed oil to low-temperature pre-conditioning treatment via a food-grade adsorption medium fixed bed; the food-grade adsorption medium fixed bed is filled with one or both of food-grade 4A molecular sieve and food-grade silica gel; or, the food-grade adsorption medium fixed bed includes a moisture adsorption layer and a polar oxidation precursor adsorption layer arranged sequentially along the oil flow direction, the moisture adsorption layer being filled with food-grade 4A molecular sieve or food-grade silica gel, and the polar oxidation precursor adsorption layer being filled with food-grade synthetic magnesium silicate.

[0027] Preferably, when the food-grade adsorption medium fixed bed is filled with food-grade 4A molecular sieve or food-grade silica gel, the low-temperature preconditioning treatment temperature is 30-60℃; when the food-grade adsorption medium fixed bed includes a polar oxidation precursor adsorption layer, the treatment temperature of the polar oxidation precursor adsorption layer is 60-85℃; the moisture content of the decolorized hemp seed oil after low-temperature preconditioning treatment is not higher than 0.03 wt.%.

[0028] Preferably, in step S5, the deodorized oil is cooled to below 60°C under vacuum or nitrogen protection conditions.

[0029] Linoleic acid, α-linolenic acid, and γ-linolenic acid in hemp seed oil contain multiple carbon-carbon double bonds. The dissociation energy of the dielyl hydrogen is lower than that of the monoallyl hydrogen, making it more prone to hydrogen abstraction reactions under conditions of heat, oxygen presence, and interfacial renewal, generating lipid free radicals. These lipid free radicals combine with dissolved oxygen to form peroxide free radicals, which further abstract hydrogen atoms from adjacent unsaturated fatty acid chains, generating lipid hydroperoxides and continuing the chain oxidation. Lipid hydroperoxides decompose under conditions of heating, interfacial exposure, and the presence of trace metal ions, forming alkoxy radicals, hydroxyl radicals, and secondary oxidation products such as aldehydes, ketones, alcohols, and acids. Trace metal ions such as iron and copper can promote the cracking of hydroperoxides, converting lipid peroxides into small-molecule carbonyl compounds and acidic compounds. These products constitute important sources of off-flavors and oxidative deterioration in hemp seed oil. When trace amounts of moisture come into contact with the ester bonds of triglycerides, hydrolysis is promoted under conditions of heating and interfacial renewal, generating free fatty acids, monoglycerides, and diglycerides. Free fatty acids are more likely to enter the gas phase or accumulate at the gas-liquid interface under vacuum and heating conditions. Their free carboxyl groups can also change the interfacial polarity environment, thereby affecting the oxidation, hydrolysis and volatilization migration processes in the oil phase.

[0030] When a food-grade adsorption medium fixed bed is placed before spray deoxygenation, food-grade molecular sieves selectively adsorb trace amounts of moisture in the oil through their pores, while food-grade silica gel adsorbs water molecules through hydrogen bonds formed by surface silanol groups, reducing the migratable moisture of the hemp seed oil before it enters the spray interface. When food-grade synthetic magnesium silicate is used as a polar oxidation precursor adsorption layer, its surface alkaline adsorption sites and porous structure adsorb polar oxidation products, hydroperoxide secondary products, free fatty acids, and trace polar impurities in the oil phase, reducing the concentration of polar components that can participate in oxidative cracking, acid catalysis, and hydrolysis side reactions under subsequent heating and interface exposure conditions. This preconditioning process does not replace decolorization, but rather adjusts the moisture state and polar oxidation precursor concentration before the decolorized oil enters the deoxygenation section, thereby reducing the concentration of side reactants in subsequent spray deoxygenation and deodorization processes.

[0031] Spray deoxygenation and spray nitrogen replacement deoxygenation transform hemp seed oil (decolorized) into dispersed oil droplets. After droplet formation, dissolved oxygen, low-boiling-point odor components, and trace amounts of water migrate from the droplet interior to the gas-liquid interface. According to Henry's Law, the dissolved oxygen concentration in the oil phase is related to the partial pressure of oxygen in the gas phase. The vacuum environment and nitrogen replacement reduce the partial pressure of oxygen outside the droplet interface, causing dissolved oxygen to be released from the oil phase to the gas phase. Nitrogen continuously removes oxygen, water vapor, and light odor components near the interface, preventing these components from reaching re-dissolution equilibrium in the gas phase and maintaining the migration direction from the oil phase to the gas phase. The large interface formed by spraying shortens the diffusion path within the oil phase and increases the contact opportunities between unsaturated fatty acids and the gas-liquid interface. Therefore, the significance of spray deoxygenation lies not only in improving gas-liquid contact efficiency but also in reducing oxygen and water in the oil phase before the deodorization stage, ensuring that the subsequent large spray interface does not become an amplified interface for oxidation and hydrolysis reactions.

[0032] Low-temperature thin-layer circulating nitrogen deoxygenation is installed after two-stage spray deoxygenation and before dual-zone spray deodorization to treat dissolved oxygen, moisture, and light odor components remaining in the oil phase after spray deoxygenation. Two-stage spray deoxygenation releases easily migratable oxygen and volatile components from the oil phase, but residual oxygen distributed with polar components, dissolved oxygen in water, and light components with slower interfacial migration may still exist. Low-temperature thin-layer circulating nitrogen deoxygenation spreads the deoxygenated oil from the two stages into a thin oil film. This thin oil film contacts a controlled thermal surface, making temperature distribution and residence time easier to control than with spray droplets. The path for residual oxygen and moisture to migrate from the bulk oil phase to the gas-liquid interface is further shortened. The countercurrent contact between circulating nitrogen and the thin oil film allows for the continuous transfer of oxygen, water vapor, and light odor components from the oil phase to the gas phase. The circulating nitrogen gas is reused after condensation, drying, deodorization, and optional deoxygenation. Moisture, entrained oil mist, odorous organic matter, and oxygen in the gas phase are continuously removed, preventing the reintroduction of moisture, odors, and oxygen into the oil phase. The thin-layer deoxygenation thus acts as a deoxygenation and moisture removal barrier before entering the deodorization section, ensuring that the subsequent high-temperature, high-vacuum spray deodorization section primarily handles odor component removal, rather than bearing the risks of oxidation and hydrolysis under residual oxygen and water conditions.

[0033] Dual-zone spray-type low-temperature deodorization removes odor components by dividing them into zones based on their volatility differences. The front-stage spray deodorization zone treats low-molecular-weight odor components such as hexanal, pentanal, heptaenal, decanadienal, and short-chain carboxylic acids, as well as residual moisture, under a relatively mild thermal process. Vacuum conditions reduce the equilibrium partial pressure of these components in the gas phase, causing them to migrate from the oil phase to the gas phase at a lower oil temperature. The rear-stage spray deodorization zone treats mid-boiling-point odor components that were not completely removed in the front stage under an even lower absolute pressure. The gradient of increasing temperature and decreasing absolute pressure causes low-boiling-point odor components to be removed from the oil phase first, reducing the volatility load in the oil phase in the rear stage and minimizing ineffective residence of the oil phase under the stronger vacuum and spray interface. The volatiles from the front and rear stages are condensed and collected separately. The front-stage condensation path is used to receive moisture and light odor components, while the rear-stage condensation path is used to receive residual odor components requiring even lower condensation conditions. This prevents volatiles with different boiling ranges from forming a compromise condensation state in the same condensation path and then migrating back to the oil phase or remaining in the gas phase pipeline. Zoned condensation also reduces secondary pollution caused by the mixing of oil mist, odor components, and moisture inside the condenser.

[0034] The cis-double bonds of unsaturated fatty acids in hemp seed oil may undergo cis-trans isomerization under high-temperature processes, and the isomerization rate increases with increasing temperature and residence time. This scheme reduces the heat load and ineffective residence time in the deodorization section by pre-inlet deoxygenation and dehydration, thin-layer deep stripping, and zoned spray deodorization, so that the migration of odor components does not depend on high-temperature and long-term treatment. After the oxygen and water in the oil phase are reduced before deodorization, the free radical chain initiation, hydrolysis reaction, and cis-trans isomerization induction factors at the spray interface are simultaneously reduced, and the thermochemical effects on the cis configuration of α-linolenic acid, γ-linolenic acid, and linoleic acid, as well as heat-sensitive accompanying components such as tocopherols and phytosterols, are weakened.

[0035] Existing low-temperature deodorization methods typically employ temperature reduction and time shortening as protective measures. However, low temperatures weaken the driving force for the volatilization of odor components, and shortening time limits the completion of mass transfer. While simply increasing the spray interface can improve mass transfer efficiency, it simultaneously amplifies the opportunities for residual oxygen and trace moisture in hemp seed oil to participate in oxidation and hydrolysis. This solution first reduces residual oxygen, moisture, and polar oxidizing precursors through oil phase preconditioning, spray deoxygenation, and thin-layer circulating nitrogen stripping. Then, it utilizes a dual-zone spray interface to complete odor migration, transforming the large interface from a potential oxidation interface into an odor component migration interface. This process chain preemptively reduces the source of reactants in hemp seed oil exposed to the large interface, rather than passively sacrificing deodorization efficiency by lowering the deodorization temperature and shortening the residence time.

[0036] Circulating nitrogen is incorporated into the deoxygenation process as a controllable gaseous medium, rather than merely as a disposable protective gas or stripping gas. The circulating gas phase undergoes condensation and dehydration to remove moisture and entrained oil mist, drying to remove residual water vapor, and deodorization to remove volatile organic odor components. Oxygen content is controlled by replenishing with high-purity nitrogen or through the deoxygenation unit, ensuring that the gas phase maintains its mass transfer capacity in the deoxygenation, dehydration, and deodorization directions when returning to the thin-layer deoxygenation unit. The circulating nitrogen loop transforms nitrogen consumption from a single-pass flow to the replenishment required to maintain gas phase purity. Condensation and dehydration reduce the moisture and oil mist load entering the vacuum system, while deodorization and optional deoxygenation reduce the pollution risks associated with gas phase reuse. From a gas phase management perspective, this supports a low-energy deodorization process.

[0037] The innovation of dual-zone spray low-temperature deodorization lies in distributing different volatile odor components to different deodorization zones and different condensation and collection paths for treatment. Compared with single-zone deodorization, the temperature, absolute pressure, residence time, and nitrogen stripping state of each deodorization zone only correspond to the range of volatile components it handles, without requiring a single zone to simultaneously satisfy the release of low-boiling-point components and the deep removal of medium-boiling-range components. After the removal of low-molecular-weight odors and residual moisture in the front stage, the volatility load required for the subsequent treatment is reduced, and the stronger vacuum conditions are concentrated on the migration of residual odor components, rather than on repeatedly carrying out already released light components. This structure reduces the additional thermal process caused by setting excessively high temperatures, excessively strong vacuums, or excessively long residence times in single-zone deodorization, which is necessary to accommodate all odor components, and allows odor removal and polyunsaturated fatty acid protection to be combined in the same continuous process.

[0038] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention, through the continuous combination of spray deoxygenation, spray nitrogen replacement deoxygenation, and low-temperature thin-layer circulating nitrogen stripping deoxygenation, reduces the content of dissolved oxygen, trace moisture, and some polar oxidizing precursors in hemp seed oil before it enters the deodorization section, thus reducing the sources of reactants for oxidation and hydrolysis reactions under large-interface spray conditions. Zoned spray low-temperature deodorization removes odor components in a gradient according to their volatility differences, and volatiles emitted from different deodorization zones are condensed and captured separately, reducing odor component re-entry and gas-phase cross-contamination. Circulating nitrogen is reused after condensation, dehydration, drying, and deodorization, reducing fresh nitrogen consumption and vacuum system load. This method improves the mass transfer removal efficiency of odor components such as aldehydes, ketones, and short-chain carboxylic acids under lower thermal processes, while inhibiting the oxidation, hydrolysis, and cis-trans isomerization of polyunsaturated fatty acids in hemp seed oil, reducing the loss of heat-sensitive accompanying components such as tocopherols and phytosterols, thereby obtaining a finished hemp seed oil with a pure odor and good oxidative stability. Detailed Implementation

[0039] The technical solution of the present invention will be described in detail below with reference to specific embodiments. The embodiments described herein are specific implementations of the present invention and are used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary and should not be construed as limiting the implementation of the present invention or the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the content disclosed in the claims and the specification of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein.

[0040] The chemical reagents used in the embodiments and comparative examples of this invention are all commercially available products and have not undergone any further purification treatment.

[0041] Example 1

[0042] This embodiment provides a low-energy-consumption method for ultra-short-time low-temperature deodorization of hemp seed oil, including the following steps:

[0043] S1, the decolorized hemp seed oil after degumming, deacidification, and decolorization is sent to a primary spray deoxygenation device. The moisture content of the decolorized hemp seed oil is 0.08 wt.%. Nitrogen gas with a purity of 99.99% is introduced, and the decolorized hemp seed oil is atomized into oil droplets under vacuum spray conditions and subjected to primary spray deoxygenation to obtain primary deoxygenated oil. The absolute pressure in the primary spray deoxygenation device is 3 kPa, the temperature is 78℃, and the primary spray deoxygenation time is 8 min. The water-containing gas phase discharged from the primary spray deoxygenation device is condensed and deliquescent, and then extracted by the vacuum system of the primary spray deoxygenation device. The oil droplet particle size in the primary spray deoxygenation and the secondary spray nitrogen replacement deoxygenation is 40 μm.

[0044] S2, the primary deoxidizing oil is fed into a secondary spray nitrogen replacement deoxidizing device, and nitrogen gas with a purity of 99.99% is introduced. Under vacuum spray conditions, the primary deoxidizing oil is atomized into oil droplets and subjected to secondary spray nitrogen replacement deoxidation to obtain secondary deoxidizing oil; the absolute pressure in the secondary spray nitrogen replacement deoxidizing device is 1.5 kPa, the temperature is 82℃, and the secondary spray nitrogen replacement deoxidation time is 5 min;

[0045] S3, the secondary deoxygenated oil is fed into a low-temperature thin-layer circulating nitrogen deoxygenation unit, where it spreads into a thin oil film and undergoes countercurrent contact with purified circulating nitrogen for deoxygenation, resulting in a thin-layer deoxygenated oil. The low-temperature thin-layer circulating nitrogen deoxygenation unit is a falling film degasser, the thickness of the thin oil film is 0.4 mm, the temperature of the unit is 88°C, the absolute pressure is 1.0 kPa, and the deoxygenation time is 3 min. After being discharged from the unit, the circulating nitrogen passes through a condensation and dehydration unit, a drying unit, and a deodorization unit before returning to the unit. The oxygen content in the recycled nitrogen is controlled to be no higher than 35 ppmv through partial discharge and replenishment of 99.99% pure high-purity nitrogen. The drying unit is filled with 4A molecular sieves, and the deodorization unit is filled with food-grade activated carbon.

[0046] S4, the thin-layer deoxygenated oil is fed into a dual-zone spray-type low-temperature deodorization device, sequentially passing through a front spray deodorization zone and a rear spray deodorization zone for spray deodorization. The volatiles discharged from both the front and rear spray deodorization zones are condensed and collected to obtain deodorized oil. The temperature of the front spray deodorization zone is 100℃, the absolute pressure is 300Pa, and the residence time is 2min. The temperature of the rear spray deodorization zone is 125℃, the absolute pressure is 50Pa, and the residence time is 3min. In the downstream spray deodorization zone, nitrogen is used as the atomizing medium and stripping gas. The nitrogen is preheated to 15°C higher than the oil temperature in the upstream spray deodorization zone before entering the downstream spray deodorization zone, and the nitrogen is also preheated to 15°C higher than the oil temperature in the downstream spray deodorization zone before entering the downstream spray deodorization zone. The volatiles discharged from the upstream spray deodorization zone are collected by the first condensation and collection unit, and the volatiles discharged from the downstream spray deodorization zone are collected by the second condensation and collection unit. The condensation temperature of the first condensation and collection unit is 0°C, and the condensation temperature of the second condensation and collection unit is -25°C.

[0047] S5, the deodorized oil is cooled to 55°C under nitrogen protection to obtain the finished hemp seed oil.

[0048] Example 2

[0049] This embodiment provides a low-energy-consumption method for ultra-short-time low-temperature deodorization of hemp seed oil, including the following steps:

[0050] S1, the decolorized hemp seed oil after degumming, deacidification, and decolorization is sent to a primary spray deoxygenation device. The moisture content of the decolorized hemp seed oil is 0.10 wt.%. Nitrogen gas with a purity of 99.99% is introduced, and the decolorized hemp seed oil is atomized into oil droplets under vacuum spray conditions and subjected to primary spray deoxygenation to obtain primary deoxygenated oil. The absolute pressure in the primary spray deoxygenation device is 5 kPa, the temperature is 60℃, and the primary spray deoxygenation time is 12 min. The water-containing gas phase discharged from the primary spray deoxygenation device is condensed and deliquescent, and then extracted by the vacuum system of the primary spray deoxygenation device. The oil droplet particle size in the primary spray deoxygenation and the secondary spray nitrogen replacement deoxygenation is 80 μm.

[0051] S2, the primary deoxidizing oil is fed into a secondary spray nitrogen replacement deoxidizing device, and nitrogen gas with a purity of 99.99% is introduced. Under vacuum spray conditions, the primary deoxidizing oil is atomized into oil droplets and subjected to secondary spray nitrogen replacement deoxidation to obtain secondary deoxidizing oil; the absolute pressure in the secondary spray nitrogen replacement deoxidizing device is 3 kPa, the temperature is 70℃, and the secondary spray nitrogen replacement deoxidation time is 8 min;

[0052] S3, the secondary deoxidized oil is fed into a low-temperature thin-layer circulating nitrogen deoxidation unit, where it spreads into a thin oil film and undergoes countercurrent contact with purified circulating nitrogen for deoxidation, resulting in a thin-layer deoxidized oil. The low-temperature thin-layer circulating nitrogen deoxidation unit is a scraped-film evaporator. The thickness of the thin oil film is 0.8 mm. The temperature of the unit is 80°C, the absolute pressure is 2 kPa, and the deoxidation time is 5 minutes. After the circulating nitrogen is discharged from the low-temperature thin-layer circulating nitrogen deoxidation unit... After passing through a condensation and dehydration unit, a drying unit, and a deodorization unit, the nitrogen is returned to the low-temperature thin-layer circulating nitrogen deoxygenation unit. The oxygen content in the recycled nitrogen is controlled to be no higher than 50 ppmv through partial discharge and replenishment of high-purity nitrogen (99.99% purity). The drying unit is filled with 3A molecular sieves, and the deodorization unit is filled with food-grade activated carbon. Before returning to the low-temperature thin-layer circulating nitrogen deoxygenation unit, the circulating nitrogen is also treated by a deoxygenation unit filled with a reduced copper-based deoxidizer.

[0053] S4, the thin-layer deoxidized oil is fed into a dual-zone spray-type low-temperature deodorization device, sequentially passing through a front spray deodorization zone and a rear spray deodorization zone for spray deodorization. The volatiles discharged from both the front and rear spray deodorization zones are condensed and collected to obtain deodorized oil. The temperature of the front spray deodorization zone is 90℃, the absolute pressure is 500Pa, and the residence time is 3min. The temperature of the rear spray deodorization zone is 115℃, the absolute pressure is 80Pa, and the residence time is 5min. Nitrogen is used as both the atomizing medium and the stripping gas in the downstream spray deodorization zone. The nitrogen is preheated to 25°C above the oil temperature of the upstream spray deodorization zone before entering it, and the nitrogen is also preheated to 25°C above the oil temperature of the downstream spray deodorization zone before entering it. The volatiles discharged from the upstream spray deodorization zone are collected by a first condensation and collection unit, and the volatiles discharged from the downstream spray deodorization zone are collected by a second condensation and collection unit. The condensation temperature of the first condensation and collection unit is 10°C, and the condensation temperature of the second condensation and collection unit is -10°C.

[0054] S5, the deodorized oil is cooled to 58°C under vacuum to obtain the finished hemp seed oil.

[0055] Example 3

[0056] This embodiment provides a low-energy-consumption method for ultra-short-time low-temperature deodorization of hemp seed oil, including the following steps:

[0057] Before step S1, the decolorized hemp seed oil, after degumming, deacidification, and decolorization, undergoes low-temperature pre-conditioning treatment via a food-grade adsorption medium fixed bed. The moisture content of the decolorized hemp seed oil before the low-temperature pre-conditioning treatment is 0.08 wt.%. The food-grade adsorption medium fixed bed is filled with food-grade 4A molecular sieves and food-grade silica gel. The low-temperature pre-conditioning treatment temperature is 30°C. After the low-temperature pre-conditioning treatment, the moisture content of the decolorized hemp seed oil is 0.03 wt.%.

[0058] S1, the decolorized hemp seed oil after low-temperature pre-conditioning is fed into a primary spray deoxygenation device. The moisture content of the decolorized hemp seed oil is 0.03 wt.%. Nitrogen gas with a purity of 99.99% is introduced, and the decolorized hemp seed oil is atomized into oil droplets under vacuum spray conditions and subjected to primary spray deoxygenation to obtain primary deoxygenated oil. The absolute pressure in the primary spray deoxygenation device is 1 kPa, the temperature is 85℃, and the primary spray deoxygenation time is 4 min. The water-containing gas phase discharged from the primary spray deoxygenation device is condensed and deliquescent, and then extracted by the vacuum system of the primary spray deoxygenation device. The oil droplet particle size in the primary spray deoxygenation and the secondary spray nitrogen replacement deoxygenation is 10 μm.

[0059] S2, the primary deoxidizing oil is fed into a secondary spray nitrogen replacement deoxidizing device, and nitrogen gas with a purity of 99.99% is introduced. Under vacuum spray conditions, the primary deoxidizing oil is atomized into oil droplets and subjected to secondary spray nitrogen replacement deoxidation to obtain secondary deoxidizing oil; the absolute pressure in the secondary spray nitrogen replacement deoxidizing device is 0.5 kPa, the temperature is 95℃, and the secondary spray nitrogen replacement deoxidation time is 2 min;

[0060] S3, the secondary deoxidized oil is fed into a low-temperature thin-film circulating nitrogen deoxidation unit, where it spreads into a thin oil film and undergoes countercurrent contact with purified circulating nitrogen for deoxidation, resulting in a thin-film deoxidized oil. The low-temperature thin-film circulating nitrogen deoxidation unit is a centrifugal thin-film evaporator. The thickness of the thin oil film is 0.1 mm. The temperature of the low-temperature thin-film circulating nitrogen deoxidation unit is 100°C, the absolute pressure is 0.3 kPa, and the deoxidation time is 0.5 min. The circulating nitrogen passes through the low-temperature thin-film circulating nitrogen deoxidation unit... After being discharged, the nitrogen gas passes through a condensation and dehydration unit, a drying unit, and a deodorization unit before returning to the low-temperature thin-layer circulating nitrogen deoxygenation unit. Through partial discharge and replenishment of high-purity nitrogen (99.99%), the oxygen content in the recycled nitrogen is controlled to be no higher than 20 ppmv. The drying unit is filled with silica gel desiccant, and the deodorization unit is filled with food-grade activated carbon. Before returning to the low-temperature thin-layer circulating nitrogen deoxygenation unit, the circulating nitrogen gas also undergoes deoxygenation treatment, where it is filled with a reduced copper-based deoxygenating agent.

[0061] S4, the thin-layer deoxygenated oil is fed into a dual-zone spray-type low-temperature deodorization device, sequentially passing through a front spray deodorization zone and a rear spray deodorization zone for spray deodorization. The volatiles discharged from both the front and rear spray deodorization zones are condensed and collected to obtain deodorized oil. The temperature of the front spray deodorization zone is 115℃, the absolute pressure is 100Pa, and the residence time is 0.5min. The temperature of the rear spray deodorization zone is 135℃, the absolute pressure is 20Pa, and the residence time is 1min. The downstream spray deodorization zone uses nitrogen as both the atomizing medium and the stripping gas. The nitrogen is preheated to 5°C above the oil temperature of the upstream spray deodorization zone before entering it, and the nitrogen is also preheated to 5°C above the oil temperature of the downstream spray deodorization zone before entering it. The volatiles discharged from the upstream spray deodorization zone are collected by a first condensation and collection unit, and the volatiles discharged from the downstream spray deodorization zone are collected by a second condensation and collection unit. The condensation temperature of the first condensation and collection unit is -5°C, and the condensation temperature of the second condensation and collection unit is -40°C.

[0062] S5, the deodorized oil is cooled to 50°C under nitrogen protection to obtain the finished hemp seed oil.

[0063] Example 4

[0064] This embodiment provides a low-energy-consumption method for ultra-short-time low-temperature deodorization of hemp seed oil, including the following steps:

[0065] Before step S1, the decolorized hemp seed oil, after degumming, deacidification, and decolorization, undergoes low-temperature pre-conditioning treatment via a food-grade adsorption medium fixed bed. The moisture content of the decolorized hemp seed oil before the low-temperature pre-conditioning treatment is 0.07 wt.%. The food-grade adsorption medium fixed bed includes a moisture adsorption layer and a polar oxidation precursor adsorption layer arranged sequentially along the oil flow direction. The moisture adsorption layer is filled with food-grade 4A molecular sieve, and the polar oxidation precursor adsorption layer is filled with food-grade synthetic magnesium silicate. The treatment temperature of the polar oxidation precursor adsorption layer is 85°C, and the moisture content of the decolorized hemp seed oil after the low-temperature pre-conditioning treatment is 0.02 wt.%.

[0066] S1, the decolorized hemp seed oil after low-temperature pre-conditioning is fed into a primary spray deoxygenation device. The moisture content of the decolorized hemp seed oil is 0.02 wt.%. Nitrogen gas with a purity of 99.99% is introduced, and the decolorized hemp seed oil is atomized into oil droplets under vacuum spray conditions and subjected to primary spray deoxygenation to obtain primary deoxygenated oil. The absolute pressure in the primary spray deoxygenation device is 2 kPa, the temperature is 70°C, and the primary spray deoxygenation time is 10 min. The water-containing gas phase discharged from the primary spray deoxygenation device is condensed and deliquescent, and then extracted by the vacuum system of the primary spray deoxygenation device. The oil droplet particle size in the primary spray deoxygenation and the secondary spray nitrogen replacement deoxygenation is 60 μm.

[0067] S2, the primary deoxidizing oil is fed into a secondary spray nitrogen replacement deoxidizing device, and nitrogen gas with a purity of 99.99% is introduced. Under vacuum spray conditions, the primary deoxidizing oil is atomized into oil droplets and subjected to secondary spray nitrogen replacement deoxidation to obtain secondary deoxidizing oil; the absolute pressure in the secondary spray nitrogen replacement deoxidizing device is 1.8 kPa, the temperature is 88℃, and the secondary spray nitrogen replacement deoxidation time is 6 min;

[0068] S3, the secondary deoxygenated oil is fed into a low-temperature thin-layer circulating nitrogen deoxygenation unit, where it spreads into a thin oil film and undergoes countercurrent contact with purified circulating nitrogen for deoxygenation, resulting in a thin-layer deoxygenated oil. The low-temperature thin-layer circulating nitrogen deoxygenation unit is a falling film degasser, the thickness of the thin oil film is 0.6 mm, the temperature of the unit is 92°C, the absolute pressure is 1.5 kPa, and the deoxygenation time is 4 min. After being discharged from the unit, the circulating nitrogen passes through a condensation and dehydration unit, a drying unit, and a deodorization unit before returning to the unit. The oxygen content in the recycled nitrogen is controlled to be no higher than 40 ppmv through partial discharge and replenishment of 99.99% pure high-purity nitrogen. The drying unit is filled with 4A molecular sieves, and the deodorization unit is filled with food-grade activated carbon.

[0069] S4, the thin-layer deoxygenated oil is fed into a dual-zone spray-type low-temperature deodorization device, sequentially passing through a front spray deodorization zone and a rear spray deodorization zone for spray deodorization. The volatiles discharged from both the front and rear spray deodorization zones are condensed and collected to obtain deodorized oil. The temperature of the front spray deodorization zone is 108℃, the absolute pressure is 400Pa, and the residence time is 2.5min. The temperature of the rear spray deodorization zone is 130℃, the absolute pressure is 60Pa, and the residence time is 4min. The downstream spray deodorization zone uses nitrogen as both the atomizing medium and the stripping gas. The nitrogen is preheated to 10°C above the oil temperature of the upstream spray deodorization zone before entering it, and to 20°C above the oil temperature of the downstream spray deodorization zone before entering it. Volatile substances discharged from the upstream spray deodorization zone are collected by a first condensation and collection unit, and volatile substances discharged from the downstream spray deodorization zone are collected by a second condensation and collection unit. The condensation temperature of the first condensation and collection unit is 5°C, and the condensation temperature of the second condensation and collection unit is -30°C.

[0070] S5, the deodorized oil is cooled to 52°C under vacuum to obtain the finished hemp seed oil.

[0071] Comparative Example 1

[0072] This comparative example provides a method for deodorizing hemp seed oil. The difference from Example 1 is that it does not employ a first-stage spray deoxygenation, a second-stage spray nitrogen replacement deoxygenation, a low-temperature thin-layer circulating nitrogen deoxygenation unit, or a dual-zone spray low-temperature deodorization device. Instead, the decolorized hemp seed oil, after degumming, deacidification, and decolorization treatment, is fed into a conventional deodorization tower. Saturated steam is used for stripping deodorization. The temperature of the deodorization tower is 240°C, the absolute pressure is 300Pa, the steam flow rate is 2.0 wt.% of the oil mass, and the deodorization time is 90 min. After deodorization, the oil is cooled to 55°C under nitrogen protection to obtain the finished hemp seed oil.

[0073] Comparative Example 2

[0074] This comparative example provides a low-energy-consumption method for ultra-short-time low-temperature deodorization of hemp seed oil. The difference from Example 1 is that S3 is omitted, and the secondary deoxygenated oil obtained in S2 is directly sent to a dual-zone spray-type low-temperature deodorization device for spray deodorization. The remaining steps and process conditions are the same as in Example 1.

[0075] Comparative Example 3

[0076] This comparative example provides a low-energy-consumption ultra-short-time low-temperature deodorization method for hemp seed oil. The difference from Example 1 is that in S4, instead of using a front-end spray deodorization zone and a rear-end spray deodorization zone for dual-zone spray deodorization, a thin layer of deoxygenated oil is sent into a single-zone spray-type low-temperature deodorization device for spray deodorization. The deodorization temperature is 125°C, the absolute pressure is 50Pa, the residence time is 5min, and the nitrogen gas is preheated to 140°C before entering the single-zone spray deodorization device. The volatiles discharged from the single-zone spray deodorization are uniformly condensed and collected at a condensation temperature of -25°C. The remaining steps and process conditions are the same as in Example 1.

[0077] Comparative Example 4

[0078] This comparative example provides a low-energy-consumption method for ultra-short-time low-temperature deodorization of hemp seed oil. The difference from Example 1 is that, in S3, the circulating nitrogen gas discharged after passing through the low-temperature thin-layer circulating nitrogen deoxygenation unit does not pass through the condensation and dehydration unit, drying unit, and deodorization unit. Instead, it is only partially discharged and replenished with high-purity nitrogen gas with a purity of 99.99% for recycling. The remaining steps and process conditions are the same as in Example 1.

[0079] Test method:

[0080] The same batch of decolorized hemp seed oil, after degumming, deacidification, and decolorization treatment, was used as the raw material for each example and comparative example. The finished hemp seed oils obtained from each example and comparative example were stored under light-proof, nitrogen-filled, and sealed conditions, and equilibrated at 25°C for 30 minutes before testing. Each sample was measured in triplicate, and the average value was taken as the test result. The product indicators of each comparative example were compared with the finished hemp seed oil obtained in Example 1.

[0081] Taste and odor testing methods: The test shall be conducted according to the method specified in section 6 of GB / T 5525-2008. Take an appropriate amount of the finished hemp seed oil and place it in a clean container. Observe and evaluate whether it has the odor and taste of hemp seed oil and whether there is any off-odor at room temperature.

[0082] Moisture and volatile matter test methods: The determination shall be carried out in accordance with the method specified in GB 5009.236-2016, Method II, and the results shall be expressed as % (%).

[0083] Acid value test method: The acid value shall be determined according to the method specified in GB 5009.229-2025, Method I, and the result shall be expressed as mgKOH / g.

[0084] Peroxide value test method: The test shall be conducted in accordance with the method specified in GB 5009.227-2023, Method I, and the result shall be expressed in g / 100g.

[0085] Fatty acid composition test method: The determination shall be carried out in accordance with the normalization method of GB 5009.168-2016, the third method. The test items include linoleic acid, linolenic acid, oleic acid, palmitic acid and stearic acid. The results are expressed as %.

[0086] Squalene test method: The test shall be performed in accordance with the method specified in LS / T 6120-2017, and the result shall be expressed in mg / kg.

[0087] Vitamin E test method: The test shall be conducted in accordance with the method specified in GB 5009.82-2016, Method II. The test items include vitamin E, α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol and vitamin E (α-tocopherol equivalent). The results of vitamin E and each tocopherol component are expressed in mg / 100g, and vitamin E (α-tocopherol equivalent) is expressed in mgα-TE / 100g.

[0088] Total sterols test method: The test shall be conducted in accordance with the method specified in GB / T 25223-2024 Method I. The test items include total sterols and each sterol component. The results are expressed in mg / kg.

[0089] The test results are shown in Tables 1 to 3.

[0090] Table 1. Basic quality test results of finished hemp seed oil from Examples 1-4 and Comparative Examples 1-4

[0091]

[0092] Table 2. Test results of fatty acid composition of finished hemp seed oil from Examples 1-4 and Comparative Examples 1-4

[0093]

[0094] Table 3. Test results of nutritional components in the finished hemp seed oil of Examples 1-4 and Comparative Examples 1-4

[0095]

[0096] As shown in Tables 1 to 3, compared to Example 1, Comparative Example 1 showed a decrease in moisture and volatile matter, a decrease in peroxide value, an increase in acid value, and a decrease in the total amount of linoleic acid, linolenic acid, squalene, vitamin E, α-tocopherol, γ-tocopherol, δ-tocopherol, and sterols; Comparative Example 2 showed an increase in moisture and volatile matter, an increase in acid value and peroxide value, and a decrease in the total amount of linoleic acid, linolenic acid, squalene, vitamin E, α-tocopherol, γ-tocopherol, δ-tocopherol, and sterols; Comparative Example 3 showed an increase in moisture and volatile matter, an increase in acid value and peroxide value, and a decrease in the total amount of linoleic acid, linolenic acid, squalene, vitamin E, α-tocopherol, γ-tocopherol, δ-tocopherol, and sterols; Comparative Example 4 showed an increase in moisture and volatile matter, an increase in acid value and peroxide value, and a decrease in the total amount of linoleic acid, linolenic acid, squalene, vitamin E, α-tocopherol, γ-tocopherol, δ-tocopherol, and sterols.

[0097] This is because Comparative Example 1 uses conventional high-temperature steam stripping deodorization. The higher thermal process and longer treatment time reduce moisture and some primary peroxides, but the high temperature promotes the hydrolysis of glycerides and the thermal oxidation of polyunsaturated fatty acids, increasing the acid value and leading to a decrease in the total amount of linoleic acid, linolenic acid, squalene, vitamin E, and sterols. Comparative Example 2 omits the low-temperature thin-layer circulating nitrogen deoxygenation unit. The residual moisture and easily oxidized components in the secondary deoxygenated oil are not further removed. After entering the dual-zone spray deodorization section, hydrolysis and oxidation are more likely to occur under heating and large interface contact conditions, increasing moisture, volatile matter, acid value, and peroxide value, and affecting the fatty acid composition and accompanying nutritional components.

[0098] Comparative Example 3 employed a single-zone spray-type low-temperature deodorization method, eliminating the temperature increase, absolute pressure decrease, and zoned condensation and capture between the front and rear spray deodorization zones. This resulted in different volatile components being concentrated in the same area during deodorization, leading to insufficient exposure of the oil phase interface and thermal path distribution. Consequently, moisture, volatiles, acid value, and peroxide value increased, while the total amounts of linoleic acid, linolenic acid, vitamin E, and sterols decreased. In Comparative Example 4, the circulating nitrogen was reused without condensation, dehydration, drying, and deodorization treatment. Moisture, oil mist, and volatile components entrained in the recycled gas phase were not effectively removed. This reduced the driving force for oil phase migration to the gas phase during thin-layer deoxygenation, causing moisture and odor components to migrate back, increasing moisture, volatiles, acid value, and peroxide value, while simultaneously decreasing the total amounts of squalene, vitamin E, and sterols.

[0099] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A low-energy-consumption method for ultra-short-time low-temperature deodorization of hemp seed oil, characterized in that, Includes the following steps: S1, the decolorized hemp seed oil after degumming, deacidification and decolorization is sent to the first-stage spray deoxygenation device, nitrogen is introduced, and the decolorized hemp seed oil is atomized into oil droplets under vacuum spraying conditions and subjected to first-stage spray deoxygenation to obtain first-stage deoxygenated oil. S2, the primary deoxygenated oil is sent to the secondary spray nitrogen replacement deoxygenation device, nitrogen is introduced, and the primary deoxygenated oil is atomized into oil droplets under vacuum spray conditions and then subjected to secondary spray nitrogen replacement deoxygenation to obtain secondary deoxygenated oil. S3, the secondary deoxygenated oil is sent into the low-temperature thin-layer circulating nitrogen deoxygenation unit, spread into a thin-layer oil film, and then deoxygenated by countercurrent contact with purified circulating nitrogen to obtain thin-layer deoxygenated oil. S4, the thin-layer deoxygenated oil is fed into a dual-zone spray-type low-temperature deodorization device, passing sequentially through a front spray deodorization zone and a rear spray deodorization zone. The temperature of the rear spray deodorization zone is higher than that of the front spray deodorization zone, and the absolute pressure of the rear spray deodorization zone is lower than that of the front spray deodorization zone. The volatiles discharged from the front spray deodorization zone and the rear spray deodorization zone are condensed and collected to obtain deodorized oil. S5, the deodorized oil is cooled under vacuum or nitrogen protection to obtain the finished hemp seed oil.

2. The low-energy-consumption method for ultra-short-time low-temperature deodorization of hemp seed oil according to claim 1, characterized in that, In S1, the moisture content of the decolorized hemp seed oil is not higher than 0.10 wt.%, the absolute pressure in the first-stage spray deoxygenation device is 1-5 kPa, the temperature is 60-85℃, the first-stage spray deoxygenation time is 4-12 min, and the water-containing gas phase discharged from the first-stage spray deoxygenation device is extracted by the vacuum system of the first-stage spray deoxygenation device after condensation and liquid removal.

3. The low-energy-consumption ultra-short-time low-temperature deodorization method for hemp seed oil according to claim 1, characterized in that, In S2, the absolute pressure inside the secondary spray nitrogen replacement deoxygenation device is 0.5-3 kPa, the temperature is 70-95℃, and the secondary spray nitrogen replacement deoxygenation time is 2-8 min.

4. The low-energy-consumption ultra-short-time low-temperature deodorization method for hemp seed oil according to claim 1, characterized in that, In S1 and S2, the oil droplet size in the primary spray deoxygenation and the secondary spray nitrogen replacement deoxygenation is 10-80 μm, and the purity of the nitrogen is not less than 99.99%.

5. The low-energy-consumption ultra-short-time low-temperature deodorization method for hemp seed oil according to claim 1, characterized in that, In S3, the low-temperature thin-film circulating nitrogen deoxygenation unit is a falling film degasser, a scraped film evaporator, or a centrifugal thin-film evaporator, and the thickness of the thin oil film is 0.1-0.8 mm.

6. The low-energy-consumption ultra-short-time low-temperature deodorization method for hemp seed oil according to claim 1, characterized in that, In S3, the temperature of the low-temperature thin-layer circulating nitrogen deoxygenation unit is 80-100℃, the absolute pressure is 0.3-2kPa, and the thin-layer deoxygenation time is 0.5-5min.

7. The low-energy-consumption ultra-short-time low-temperature deodorization method for hemp seed oil according to claim 1, characterized in that, In S3, after the circulating nitrogen is discharged through the low-temperature thin-layer circulating nitrogen deoxygenation unit, it is processed sequentially through the condensation and dehydration unit, the drying unit, and the deodorization unit before returning to the low-temperature thin-layer circulating nitrogen deoxygenation unit. By partially discharging and replenishing high-purity nitrogen with a purity of not less than 99.99%, the oxygen content in the recycled nitrogen is controlled to be no higher than 50 ppmv.

8. The low-energy-consumption ultra-short-time low-temperature deodorization method for hemp seed oil according to claim 7, characterized in that, The drying unit is filled with 3A molecular sieve, 4A molecular sieve or silica gel desiccant, and the deodorizing unit is filled with food-grade activated carbon.

9. The low-energy-consumption ultra-short-time low-temperature deodorization method for hemp seed oil according to claim 7, characterized in that, Before returning to the low-temperature thin-layer circulating nitrogen deoxidation unit, the circulating nitrogen is further processed by a deoxidation unit filled with a reduced copper-based deoxidizer.

10. The low-energy-consumption ultra-short-time low-temperature deodorization method for hemp seed oil according to claim 1, characterized in that, In S4, the temperature of the front spray deodorization zone is 90-115℃, the absolute pressure is 100-500Pa, and the residence time is 0.5-3min; the temperature of the rear spray deodorization zone is 115-135℃, the absolute pressure is 20-80Pa, and the residence time is 1-5min.

11. The low-energy-consumption ultra-short-time low-temperature deodorization method for hemp seed oil according to claim 1, characterized in that, In S4, both the front spray deodorization zone and the rear spray deodorization zone use nitrogen as the atomizing medium and stripping gas; the nitrogen is preheated to 5-25°C higher than the oil temperature of the front spray deodorization zone before entering the front spray deodorization zone, and the nitrogen is preheated to 5-25°C higher than the oil temperature of the rear spray deodorization zone before entering the rear spray deodorization zone.

12. The low-energy-consumption method for ultra-short-time low-temperature deodorization of hemp seed oil according to claim 1, characterized in that, In S4, the volatiles discharged from the front spray deodorization zone are collected by the first condensation and collection unit, and the volatiles discharged from the rear spray deodorization zone are collected by the second condensation and collection unit. The condensation temperature of the first condensation and collection unit is -5℃ to 10℃, and the condensation temperature of the second condensation and collection unit is -40℃ to -10℃.

13. The low-energy-consumption ultra-short-time low-temperature deodorization method for hemp seed oil according to claim 1, characterized in that, Before S1, the process further includes subjecting the decolorized hemp seed oil to low-temperature pre-conditioning treatment via a food-grade adsorption medium fixed bed; the food-grade adsorption medium fixed bed is filled with one or both of food-grade 4A molecular sieve and food-grade silica gel; or, the food-grade adsorption medium fixed bed includes a moisture adsorption layer and a polar oxidation precursor adsorption layer arranged sequentially along the oil flow direction, the moisture adsorption layer is filled with food-grade 4A molecular sieve or food-grade silica gel, and the polar oxidation precursor adsorption layer is filled with food-grade synthetic magnesium silicate.

14. The low-energy-consumption ultra-short-time low-temperature deodorization method for hemp seed oil according to claim 13, characterized in that, When the food-grade adsorption medium fixed bed is filled with food-grade 4A molecular sieve or food-grade silica gel, the low-temperature preconditioning treatment temperature is 30-60℃; when the food-grade adsorption medium fixed bed includes a polar oxidation precursor adsorption layer, the treatment temperature of the polar oxidation precursor adsorption layer is 60-85℃; the moisture content of the decolorized hemp seed oil after low-temperature preconditioning treatment is not higher than 0.03wt.%.

15. The low-energy-consumption ultra-short-time low-temperature deodorization method for hemp seed oil according to claim 1, characterized in that, In S5, the deodorized oil is cooled to below 60°C under vacuum or nitrogen protection conditions.

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