Continuous subcritical carbon dioxide extraction isobaric separation process of sesame seeds

Abstract

The present application relates to oil full value utilization processing technical field, especially to continuous subcritical carbon dioxide extraction isobaric separation process of sesame seed, including the following steps and conditions: (1) sesame seed dust removal and impurity removal; (2) crushing sesame seed, and passing 10-30 mesh screen; (3) loading; (4) using pressure 23±1MPa, temperature 28±2℃, flow (33~167) ±2L.h-1.kg ‑1 Subcritical carbon dioxide extraction (crushing raw material) crushes sesame seed, and extraction duration is 1~23h; (5) subcritical carbon dioxide is changed into supercritical carbon dioxide with temperature 65±2℃ and pressure equal to extraction pressure, and sesame oil is separated therefrom, and extraction rate is 33.4%~99.5%; (6) unloading; (5) clarifying or filtering treatment sesame crude oil to obtain sesame essential oil, and grinding and screening defatted sesame crude powder to obtain sesame essential powder; The process flow adopted by the present application is simple, the process condition is easy to control, the obtained sesame oil and defatted sesame powder are good in quality, high in production efficiency and excellent in economy.

Description

Technical Field

[0001] This invention relates to extraction and separation technology in the field of oilseed processing and utilization, and particularly to a continuous subcritical carbon dioxide extraction isobaric separation process for sesame seeds. Background Technology

[0002] Sesame seeds, also known as sesame seeds, are the seeds of the sesame plant (Sesamum indicum), belonging to the genus Sesame in the family Sesaceae. They come in four colors: black, white, yellow, and brown. Black sesame seeds are called black sesame seeds, and white sesame seeds are called white sesame seeds. On average, domestically produced sesame seeds in my country contain about 27.1% protein, containing all eight essential amino acids. Essential amino acids account for 30% of the total amino acids, and except for lysine and isoleucine, the other amino acids can meet the body's needs. They also contain an average of about 52.3% oil, of which 85% is unsaturated fatty acids, with oleic acid and linoleic acid exceeding 40%, stearic acid averaging 4.9%, and palmitic acid 9.6%. Sesamin content is 3.34 g / kg, and sesamin content is 1.48 g / kg. Additionally, they contain carbohydrates, dietary fiber, and various trace elements such as selenium, calcium, iron, and magnesium, as well as vitamin E. Traditional sesame oil pressing and water extraction methods easily destroy the nutrients in sesame seeds and have low oil extraction efficiency. Furthermore, most of the residue left after oil extraction cannot be reused, further reducing the added value of sesame seeds. Although supercritical carbon dioxide extraction technology is considered a green extraction and separation technology, it is difficult to use for sesame seed processing due to high extraction pressure, large equipment investment, constant pressure switching between extraction and separation, and high operating energy consumption.

[0003] On June 30, 2020, the Patent Office of the State Intellectual Property Office of China granted an invention patent with publication number CN108654135 B, entitled "A Subcritical Fluid Isobaric Extraction and Separation System and Process Flow". This patent utilizes the characteristic that the solubility of the extracted substance in the subcritical state of the same extraction medium under the same pressure is higher than that in the supercritical state, proposing a subcritical fluid isobaric extraction and separation system and process flow. This eliminates the disadvantages of continuous pressure switching between extraction and separation and high energy consumption. However, the patent does not propose measures to ensure isobaric pressure between extraction and separation.

[0004] On May 14, 2021, the Patent Office of the State Intellectual Property Office of China granted an invention patent with publication number CN110152350B, entitled "A Subcritical Fluid Continuous Isobaric Extraction and Separation Device System and Extraction and Separation Process." This invention proposes a cylinder-type extractor structure, in which the cylinder is filled with multiple cup-shaped hoppers. Under the action of loading and unloading hydraulic cylinders, each hopper enters the extraction cylinder in a linear motion, passing through a pressure-increasing zone, an extraction pressure zone, and a pressure-decreasing zone, before exiting from the other end of the extraction cylinder. The movement of the hoppers achieves a self-balancing effect of gradual pressure rise and fall. While this patent can ensure isobaric pressure between extraction and separation, the loading and unloading hydraulic cylinders consume significant power, and the sealing requirements between the hoppers and the cylinder are high, resulting in severe wear and frequent replacement of seals.

[0005] On November 1, 2022, the Patent Office of the State Intellectual Property Office of China granted an invention patent with publication number CN114263780A, entitled "A Pressure Gradual Increase and Decrease Self-Balancing High-Pressure or Ultra-High-Pressure Valve Switching System." For extraction, the invented switching system consists of a supply valve, a supply pipe, a return valve, a return pipe, a pressure balancing valve, a pressure balancing pipe, a venting and backpressure valve, a venting pipe, and multiple extractors. In this switching system, through the switching of the pressure balancing valve, the extracted extractor is gradually depressurized from its working pressure to near atmospheric pressure, while the extractor to be extracted is gradually pressurized from atmospheric pressure to near working pressure. The number of extractors undergoing gradual depressurization is the same as the number of extractors undergoing gradual pressurization, and equal to the number of pressurization or depressurization stages. This system ensures the continuity of extraction and isobaricity of separation, but requires twice the number of extractors undergoing gradual pressurization or depressurization stages to be in a non-working state, reducing the efficiency of the extractors. On September 5, 2023, the Patent Office of the State Intellectual Property Office of China published an invention patent with announcement number CN116688559A entitled "A Multi-state Fluid Continuous Extraction Iso- / Depressurization Separation System and Extraction Separation Process". The continuous extraction subsystem of this invention also consists of a supply valve, a supply pipe, a return valve, a return pipe, a balancing valve, a balancing and venting pipe, a venting valve, a main venting valve, and multiple extractors connected in parallel. In this switching system, through the switching of the balancing valve, the extracted extractor is gradually depressurized from its working pressure to near atmospheric pressure, while the extractor to be extracted is gradually pressurized from atmospheric pressure to near working pressure. Each depressurized extractor is counted as one, and the number of pressurized extractors is equal to the number of pressurization or depressurization stages. This system ensures the continuity of extraction and isobaric separation, and reduces the number of extractors in a non-working state to the number of pressurization or depressurization stages plus one, thus improving the efficiency of the extractors. On September 10, 2024, the Patent Office of the State Intellectual Property Office of China published an invention patent with announcement number CN118615748A entitled "A Continuous Extraction and Separation System and Process with Self-Balancing Pressure Increase and Decrease and Retraction". The continuous extraction subsystem of this invention consists of a supply valve, a supply pipe, a return valve, a return pipe, a balancing valve, a drain valve, a balancing and pressure-reducing pipe, a drain and backpressure pipe, a main drain valve, a retraction condenser, a pressure pump, and an extractor. In this switching system, by switching the balancing valve, the pressure of the extracted extractor at extraction pressure is first balanced with the pressure of the extractor to be extracted at atmospheric pressure. Then, through the action of the retraction condenser and the pressure pump, the extraction medium from the extracted extractor after pressure balancing is continued to be pumped to the extractor to be extracted, causing the pressure of the extracted extractor to drop to atmospheric pressure and the pressure of the extractor to rise to extraction pressure. The number of extractors specifically used for pressure increase and decrease is reduced to two, greatly improving the efficiency of the extractors.

[0006] In addition, the Patent Office of the State Intellectual Property Office of China published an invention patent on November 10, 2023, with the publication number CN117018671A, entitled "A Continuous Subcritical or Supercritical Fluid Extraction Device". This invention discloses a tubular extractor with a pressure-balanced feeder installed at the inlet, allowing the extractant and extractant fluid to enter the extractor together. A fluid-solid separator is installed at the outlet to separate the extractant-containing fluid from the raffinate in the fluid-solid mixture. The extractant-containing fluid flows into the extractant separation system, while the raffinate is discharged from the fluid-solid separator or enters the next extractor. This invention features high continuity, simple structure, low operating costs, and high safety and reliability.

[0007] Finally, on June 21, 2024, the Patent Office of the State Intellectual Property Office of China also published an invention patent with announcement number CN118217665A, entitled "A Supercritical / Subcritical Fluid Continuous Extractor with Ball Valve Inlet and Outlet". This invention discloses a supercritical / subcritical fluid continuous extractor with a ball valve inlet and outlet, wherein an inlet ball is installed at the inlet end and an outlet ball is installed at the outlet end; the inlet and outlet balls, similar to valve balls, have a closed cavity along a direction perpendicular to the ball's rotation axis, and a piston is installed within the cavity to facilitate the loading or unloading of the extracted material; as the inlet and outlet balls rotate synchronously and periodically, the extracted material enters and exits the extractor. This invention makes the continuous extractor structure more rational, increases the effective material holding space of the inlet and outlet balls, and simplifies manufacturing.

[0008] Depending on the pressure at which the fluid operates, subcritical fluids can be divided into subcritical gaseous fluids (below the critical pressure) and subcritical liquid fluids (above the critical pressure). The subcritical fluids described in the aforementioned seven patents are liquids.

[0009] The above six invention patents involving continuous extractor structures propose measures to ensure the continuity and isobaric process of subcritical fluid extraction isobaric separation. If these are supplemented with the optimal extraction and separation process conditions for the specific extractable, the subcritical fluid extraction isobaric separation process method will be fully utilized. Summary of the Invention

[0010] The purpose of this invention is to overcome the shortcomings of existing subcritical fluid extraction isobaric separation methods and to provide a continuous subcritical carbon dioxide extraction isobaric separation process for sesame seeds.

[0011] The technical problem to be solved by the present invention is achieved through the following technical solution: This invention is implemented using a device with continuous subcritical carbon dioxide extraction and isobaric separation capabilities. The process steps and conditions are as follows: (1) Prepare raw materials: Prepare sesame seeds by removing sand, dust, impurities and surface impurities using conventional methods; (2) Crushing and sieving: Crush the raw material and pass it through a 10-30 mesh sieve to obtain crushed raw material; (3) Loading: The crushed raw material is loaded into the extractor under vacuum from the extractor inlet, or the air in the extractor is emptied after loading is completed; (4) Extraction process: The pressure was 23±1MPa, the temperature was 28±2℃, and the flow rate was (33~167)±2L.h -1 .kg -1 Subcritical carbon dioxide extraction of pulverized raw materials for 1-23 hours; sesame oil in pulverized raw materials dissolves into subcritical carbon dioxide. (5) Separation process: Subcritical carbon dioxide containing sesame oil enters the separator and is converted into supercritical carbon dioxide at a temperature of 65±2℃ and a pressure equal to the extraction pressure, separating the sesame oil. The extraction rate of sesame oil is 33.4%~99.5%. The sesame oil extraction rate is equal to the mass of sesame oil obtained by extraction and separation divided by the sesame oil content in the pulverized raw material; (6) Unloading: The crude sesame oil is unloaded from the separator outlet; the defatted crude sesame powder is unloaded from the extract residue outlet of the extractor. Before unloading, the pressure at the extractor or its extract residue outlet shall not exceed 1.2±0.1MPa. (7) Refining: Sesame oil is obtained by clarifying or filtering crude sesame oil, and sesame powder is obtained by grinding and sieving defatted crude sesame powder.

[0012] The subcritical carbon dioxide used in this invention is in liquid form.

[0013] The beneficial effects of this invention are as follows: This invention can simultaneously obtain high-quality sesame oil and defatted sesame powder with a high oil yield. The defatted sesame powder can be further processed into various foods, improving the utilization rate and added value of raw materials. In summary, the process flow adopted by this invention is simple, the process conditions are easy to control, the sesame oil and defatted sesame powder obtained are of good quality, the production efficiency is high, and the economic benefits are excellent. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the process flow used in this invention; Figure 2 This is the curve showing the relationship between sesame oil extraction rate and extraction time in this invention; Figure 3 This is the curve showing the relationship between the sesame oil extraction rate and the extraction flow rate under the condition that the total subcritical carbon dioxide dosage remains constant, according to the present invention. Figure 4 The curve showing the relationship between the sesame oil extraction rate and the extraction flow rate under varying extraction time conditions is shown in the present invention.

[0015] Figure label: 1. Extractor 2. Heat exchanger 3. Isobaric separator 4. Circulating pump 5. Extracted material inlet 6. Extract residue outlet 7. Extracted material outlet 8. Subcritical carbon dioxide tube containing extracted material 9. Supercritical carbon dioxide tube containing extracted material 10. Supercritical carbon dioxide tube 11. Subcritical carbon dioxide tube. Detailed Implementation

[0016] The implementation process of the present invention will now be described in detail with reference to the accompanying drawings. Example

[0017] Composition of a continuous subcritical carbon dioxide extraction isobaric separation system: like Figure 1 As shown, it consists of an extractor 1, a heat exchanger 2, an isobaric separator 3, and a circulating pump 4. The extractor 1 can be a continuous extractor or a pseudo-moving bed extractor. The extractor 1 is provided with a continuous inlet for the extracted material and a continuous outlet for the raffinate. The isobaric separator 2 is provided with an extract outlet. The cold side inlet of the heat exchanger 2 is connected to the subcritical carbon dioxide outlet of the extractor 1 via the subcritical carbon dioxide pipe 8 containing the extract. The cold side outlet of the heat exchanger 2 is connected to the supercritical carbon dioxide inlet of the isobaric separator 3 via the supercritical carbon dioxide pipe 9 containing the extract. The hot side inlet of the heat exchanger 2 is connected to the supercritical carbon dioxide outlet of the isobaric separator 3 via the supercritical carbon dioxide pipe 10. The hot side outlet of the heat exchanger 2 is connected to the subcritical carbon dioxide inlet of the circulation pump 4 via the subcritical carbon dioxide pipe 11. The subcritical carbon dioxide outlet of the circulation pump 4 is connected to the subcritical carbon dioxide inlet of the extractor 1 via the subcritical carbon dioxide pipe 11.

[0018] The continuous subcritical carbon dioxide extraction isobaric separation process for sesame seeds is as follows: The extracted material is crushed sesame seeds, the extracted product is sesame oil, and the residue is sesame powder.

[0019] The crushed raw material enters from the extractant inlet of extractor 1. After extraction, the defatted sesame powder after sesame oil extraction is discharged from the extract residue outlet of extractor 1.

[0020] Subcritical carbon dioxide, driven by the circulating pump 4, enters from the subcritical carbon dioxide inlet of the extractor 1. After extracting the pulverized raw material, it exits from the subcritical carbon dioxide outlet containing sesame oil in the extractor 1 and enters the cold side inlet of the heat exchanger 2. After heat exchange, it is transformed into supercritical carbon dioxide containing sesame oil and exits from the cold side outlet of the heat exchanger 2. It then enters the isobaric separator 3 to separate the supersaturated portion of sesame oil from the supercritical carbon dioxide. The separated sesame oil exits from the isobaric separator. The separated supercritical carbon dioxide enters from the hot side inlet of the heat exchanger 2, is transformed into subcritical carbon dioxide after cooling, and exits from the hot side outlet of the heat exchanger 2. Then, under the action of the circulating pump 4, it re-enters the subcritical carbon dioxide inlet of the extractor 1 to repeat the aforementioned extraction and separation process.

[0021] The subcritical carbon dioxide in the system is in liquid state.

[0022] The continuous subcritical carbon dioxide extraction isobaric separation process steps and conditions for sesame seeds are as follows: (1) Prepare raw materials: Prepare sesame seeds by removing sand, dust, impurities and surface impurities using conventional methods; (2) Crushing and sieving: Crush the raw material and pass it through a 10-30 mesh sieve to obtain crushed raw material; (3) Loading: The crushed raw material is loaded into the extractor under vacuum from the extractor inlet, or the air in the extractor is emptied after loading is completed; (4) Extraction process: The extraction pressure was 23±1 MPa, the extraction temperature was 28±2℃, and the extraction flow rate was 100±2 L / h. -1 .kg -1 Subcritical carbon dioxide extraction of pulverized raw materials for 1 to 11.5 hours; sesame oil in pulverized raw materials dissolves into subcritical carbon dioxide. (5) Separation process: Subcritical carbon dioxide containing dissolved sesame oil enters the separation unit of the device, where it is converted into supercritical carbon dioxide at a temperature of 65±2℃ and a pressure equal to the extraction pressure, separating the dissolved sesame oil, such as... Figure 2 As shown, the extraction rate of sesame oil is 65.8%~93.2%; The sesame oil extraction rate is equal to the mass of sesame oil obtained by extraction and separation divided by the sesame oil content in the pulverized raw material; (6) Unloading: The crude sesame oil is unloaded from the separator outlet; the defatted crude sesame powder is unloaded from the extract residue outlet of the extractor. Before unloading, the pressure at the extractor or its extract residue outlet shall not exceed 1.2±0.1MPa. (7) Refining: Sesame oil is obtained by clarifying or filtering crude sesame oil, and sesame powder is obtained by grinding and sieving defatted crude sesame powder.

[0023] pass Figure 2The extraction time can be determined after setting the extraction rate. For example, if the extraction rate of sesame oil is set to 83.5%, the extraction time is 2 hours. Example

[0024] The system configuration, process flow, and process steps of continuous subcritical carbon dioxide extraction and isobaric separation, as well as the pressure and temperature during the extraction and separation processes, are the same as in Example 1; the total subcritical carbon dioxide usage is 100 L / kg. -1 (Raw material) remains constant, flow rate (50~167) ±2L.h -1 .kg -1 (Pulverized raw materials), extraction time 6.9~23h; sesame oil extraction rate 82.1%~99.5%; see Figure 3 As shown. Example

[0025] The system configuration, process flow, and process steps of continuous subcritical carbon dioxide extraction and isobaric separation, as well as the pressure and temperature during the extraction and separation processes, are the same as in Example 1; the flow rate during the extraction process is 33~117±2 L.h. -1 .kg -1 (Pulverized raw materials), extraction time 2 hours; sesame oil extraction rate 33.4%~70%.

[0026] The continuous subcritical carbon dioxide extraction isobaric separation process provided by this invention is simple in process, easy to control in process conditions, and produces high-quality sesame oil and sesame powder. It is energy-saving, environmentally friendly, highly efficient, and economically viable.

Claims

1. A continuous subcritical carbon dioxide extraction-isobaric separation process for sesame seeds, implemented using a device with continuous subcritical carbon dioxide extraction-isobaric separation capabilities, is characterized by the following process steps and conditions: (1) Prepare raw materials: Prepare sesame seeds by removing sand, dust, impurities and surface impurities using conventional methods; (2) Crushing and sieving: Crush the raw material and pass it through a 10-30 mesh sieve to obtain crushed raw material; (3) Loading: The crushed raw material is loaded into the extractor under vacuum from the extractor inlet, or the air in the extractor is emptied after loading is completed; (4) Extraction process: using pressure of 23±1 MPa, temperature of 28±2℃, flow of (33-167)±2 L.h -1 .kg -1 Subcritical carbon dioxide extraction of the crushed raw material, the extraction time is 1-23 h, and the sesame oil in the crushed raw material is dissolved in the subcritical carbon dioxide; (5) Separation process: Subcritical carbon dioxide containing sesame oil enters the separator and is converted into supercritical carbon dioxide at a temperature of 65±2℃ and a pressure equal to the extraction pressure, separating the sesame oil. The extraction rate of sesame oil is 33.4%~99.5%. The sesame oil extraction rate is equal to the mass of sesame oil obtained by extraction and separation divided by the oil content of sesame seeds in the crushed raw material. (6) Unloading: The crude sesame oil is unloaded from the separator outlet; the defatted crude sesame powder is unloaded from the extract residue outlet of the extractor. Before unloading, the pressure at the extractor or its extract residue outlet shall not exceed 1.2±0.1MPa. (7) Refining: Sesame oil is obtained by clarifying or filtering crude sesame oil, and sesame powder is obtained by grinding and sieving defatted crude sesame powder.

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