Process method for supercritical extraction of walnut oil

Abstract

The invention provides a process method for supercritical extraction of walnut oil, which comprises the following steps: pretreating a walnut kernel raw material, loading the pretreated walnut kernel, hoisting into an extraction kettle, carrying out supercritical CO2 fluid extraction on the walnut kernel for 3-4 hours, reducing the frequency of a pressure pump, carrying out supercritical CO2 fluid depressurization extraction for 0.5-1 hour, and filtering to obtain the walnut oil. Then carrying out pressure increasing and flow reducing extraction until extracted oil is less than or equal to 0.5 kg, stopping circulation of a pressure pump, stopping for flat pressing and the pressure of an extraction kettle is consistent with that of an intermediate storage tank, adjusting the system to a recovery state, starting recovery operation, and after the pressure of the extraction kettle is 0-0.2 MPa, closing the recovery system and opening the extraction kettle for emptying for pressure relief; according to the method, the extraction yield is increased in a re-boosting manner, and since the oil content of walnut kernels at the moment is only about 15%, circulating extraction is carried out by adopting a flow reducing manner, so that the operation energy consumption of supercritical extraction equipment is further reduced, the production cost is reduced, and the utilization rate is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of walnut oil preparation, and particularly relates to a process method for supercritical extraction of walnut oil. Background Art

[0002] With the continuous innovation of oil extraction technology, supercritical extraction technology has stood out in the field of oil extraction. Under the conditions of high pressure and low temperature physical extraction, it can not only achieve a higher extraction rate, but also has the advantages of no chemical solvent residue in the crude oil, which has won the favor of many experts and scholars. However, industrial equipment consumes electricity, manual operation is time-consuming and labor-intensive, the cost is too high, and the utilization rate is low. Summary of the invention

[0003] In view of the above problems, the object of the present invention is to provide a process for supercritical extraction of walnut oil with high efficiency and reduced cost.

[0004] The present invention is achieved through the following technical solutions: A process method for supercritical extraction of walnut oil comprises the following steps: pre-treating a walnut kernel raw material, loading the pre-treated walnuts, hanging them into an extraction kettle, performing supercritical CO2 fluid extraction on the walnut kernels, after extraction for 3-4 hours, reducing the frequency of a pressure pump, performing supercritical CO2 fluid pressure reduction extraction, after extraction time of 0.5-1 hour, performing pressure increase and flow reduction extraction again, until the extracted oil is less than or equal to 0.5kg, stopping the circulation of the pressure pump, shutting down the machine for pressure equalization, adjusting the system to a recovery state after the pressure of the extraction kettle is consistent with that of an intermediate storage tank, starting a recovery operation, and after the pressure of the extraction kettle is 0-0.2MPa, closing the recovery system, opening the extraction kettle to empty and release the pressure.

[0005] The walnut kernel raw material pretreatment includes microwave drying and crushing; the microwave temperature in the microwave drying is 65-75° C., and the moisture content is dried to 5%-10%; the crushing particle size is 30-60 mesh.

[0006] The extraction pressure of the walnut kernel supercritical CO2 fluid extraction is 25-55MPa, the extraction temperature is 40-50°C, the separation pressure is 6-18MPa, the separation temperature is 38-50°C, the extraction time is 3-4h, and the extraction flow rate is 2500-2700kg / h.

[0007] The extraction pressure of the walnut kernel supercritical CO2 fluid decompression extraction is 10-18MPa, the extraction temperature is 38-50°C, the separation pressure is 6-18MPa, the separation temperature is 35-50°C, the extraction time is 0.5-1h, and the extraction flow rate is 2500-2700kg / h.

[0008] The extraction pressure of the walnut kernel supercritical CO2 fluid boosting and reducing flow rate extraction is 25-55MPa, the extraction temperature is 40-50°C, the separation pressure is 6-18MPa, the separation temperature is 38-50°C, the extraction time is 1-2h, and the extraction flow rate is 1000-1800kg / h, until the extracted oil is ≤0.5kg.

[0009] The shutdown and leveling pressure controls the leveling pressure speed to be 0.001-0.10MPa / s.

[0010] Beneficial effects of the present invention: The present invention improves the extraction rate by increasing the pressure again. Since the oil content of the walnut kernel at this time is only about 15%, the circulation extraction is performed by reducing the flow rate, which once again reduces the operating energy consumption of the supercritical extraction equipment, reduces the production cost, and improves the utilization rate. DETAILED DESCRIPTION

[0011] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Example 1

[0012] The walnut kernel raw material is subjected to microwave drying at a temperature of 65, dried to a moisture content of 5%, and crushed to a particle size of 40. After the pre-treated walnuts are loaded, they are hoisted into the extraction kettle, and the equipment is adjusted to the start state. After the extraction temperature reaches the conditions, the pressure pump is started, and the extraction pressure, extraction temperature, separation pressure, separation temperature, extraction time, and extraction flow rate are set to 32MPa, 40℃, 10MPa, 38℃, 3.5h, and 2700kg / h, and the walnut kernel is extracted. After the extracted material has been extracted for 3.5h and the extraction rate has reached more than 70%, the frequency of the pressure pump is reduced, and the pressure reduction extraction is started. The extraction pressure 10MPa, extraction temperature 40℃, separation pressure 6MPa, separation temperature 35℃, extraction time 0.6h, extraction flow rate 2700kg / h. After the extracted material has been depressurized for extraction for 0.6h, start the pressure-raising and flow-reducing extraction. The extraction pressure is 34MPa, extraction temperature 40℃, separation pressure 10MPa, separation temperature 38℃, extraction time 0.9h, and extraction flow rate is 1300kg / h, until the extracted oil is ≤0.5kg. After the pressure-raising and flow-reducing walnut oil is ≤0.5kg, stop the pressure pump circulation, stop the pressure leveling, control the pressure leveling speed to 0.001-0.10MPa / s, and after the extraction kettle pressure is consistent with the intermediate storage tank, adjust the system to the recovery state and start the recovery operation. After the extraction kettle pressure is 0-0.2MPa, close the recovery system and open the extraction kettle to empty it for pressure relief. Example 2

[0013] The walnut kernel raw material is subjected to microwave drying at a temperature of 70, dried to a moisture content of 7%, and crushed to a particle size of 45. After the pre-treated walnuts are loaded, they are hoisted into the extraction kettle, and the equipment is adjusted to the start state. After the extraction temperature reaches the conditions, the pressure pump is started, and the extraction pressure, extraction temperature, and separation pressure are set to 34MPa, 45℃, 14MPa, 40℃, extraction time, 3.3h, and extraction flow rate 2700kg / h. The walnut kernel is extracted. After the extracted material has been extracted for 3.3h and the extraction yield has reached more than 70%, the frequency of the pressure pump is reduced, and the pressure reduction extraction is started. The extraction pressure 14MPa, extraction temperature 45℃, separation pressure 8MPa, separation temperature 40℃, extraction time 0.6h, extraction flow rate 2700kg / h. After the extracted material has been depressurized for extraction for 0.6h, start the pressure-raising and flow-reducing extraction, extraction pressure 36MPa, extraction temperature 45℃, separation pressure 14MPa, separation temperature 40℃, extraction time 1.1h, extraction flow rate 1500kg / h, until the extracted oil is ≤0.5kg. After the pressure-raising and flow-reducing extraction of walnut oil is ≤0.5kg, stop the pressure pump circulation, stop the pressure leveling, control the pressure leveling speed to 0.001-0.10MPa / s, after the extraction kettle pressure is consistent with the intermediate storage tank, adjust the system to the recovery state, start the recovery operation, after the extraction kettle pressure is 0-0.2MPa, close the recovery system, open the extraction kettle to empty and release the pressure. Example 3

[0014] The walnut kernel raw material is subjected to microwave drying at a temperature of 75, dried to a moisture content of 8%, and crushed to a particle size of 50. After the pre-treated walnuts are loaded, they are hoisted into the extraction kettle, and the equipment is adjusted to the start state. After the extraction temperature reaches the conditions, the pressure pump is started, and the extraction pressure, extraction temperature, separation pressure, separation temperature, and extraction time are set to 36MPa, 50℃, 16MPa, 45℃, 3.0h, and 2700kg / h. The walnut kernel is extracted. After the extracted material has been extracted for 3.0h and the extraction rate has reached more than 70%, the frequency of the pressure pump is reduced, and the pressure reduction extraction is started. The extraction pressure 16MPa, extraction temperature 50℃, separation pressure 10MPa, separation temperature 45℃, extraction time 0.6h, extraction flow rate 2700kg / h. After the extracted material has been depressurized for extraction for 0.6h, start the pressure-raising and flow-reducing extraction. The extraction pressure is 38MPa, extraction temperature 50℃, separation pressure 16MPa, separation temperature 45℃, extraction time 1.4h, extraction flow rate 1800kg / h, until the extracted oil is ≤0.5kg. After the pressure-raising and flow-reducing extraction of walnut oil is ≤0.5kg, stop the pressure pump circulation, stop the pressure leveling, control the pressure leveling speed to 0.001-0.10MPa / s, after the extraction kettle pressure is consistent with the intermediate storage tank, adjust the system to the recovery state, start the recovery operation, and after the extraction kettle pressure is 0-0.2MPa, close the recovery system, open the extraction kettle to empty and release the pressure.

[0015] Comparative Example 1 The walnut kernel raw material is subjected to microwave drying at a temperature of 65, dried to a moisture content of 5%, and a crushing particle size of 40. After the pretreated walnuts are loaded, they are hoisted into the extraction kettle, and the equipment is adjusted to the start state. After the extraction temperature reaches the conditions, the pressure pump is started, and the extraction pressure, extraction temperature, separation pressure, separation temperature, extraction time, extraction flow rate, and extraction flow rate are set to 32MPa, 40℃, 10MPa, 38℃, 7h, and 2700kg / h, and the walnut kernel is extracted. After the walnut oil is extracted to an output of ≤0.5kg, the pressure pump circulation is stopped, the machine is shut down for pressure leveling, and the pressure leveling speed is controlled to be 0.001-0.10MPa / s. After the pressure of the extraction kettle is consistent with that of the intermediate storage tank, the system is adjusted to the recovery state, and the recovery operation is started. After the pressure of the extraction kettle is 0-0.2MPa, the recovery system is closed, and the extraction kettle is opened to empty for pressure relief.

[0016] Comparative Example 2 The walnut kernel raw material is subjected to microwave drying at a temperature of 70°C, dried to a moisture content of 7%, and a crushing particle size of 45. After the pretreated walnuts are loaded, they are hoisted into the extraction kettle, and the equipment is adjusted to the start-up state. After the extraction temperature reaches the conditions, the pressure pump is started, and the extraction pressure, extraction temperature, and separation pressure are set to 34MPa, 45°C, 14MPa, 40°C, extraction time, 7h, and extraction flow rate to 2700kg / h. The walnut kernel is extracted. After the walnut oil is extracted to an output of ≤0.5kg, the pressure pump circulation is stopped, the machine is shut down for pressure leveling, and the pressure leveling speed is controlled to be 0.001-0.10MPa / s. After the pressure of the extraction kettle is consistent with that of the intermediate storage tank, the system is adjusted to the recovery state, and the recovery operation is started. After the pressure of the extraction kettle is 0-0.2MPa, the recovery system is closed, and the extraction kettle is opened to empty for pressure relief.

[0017] Comparative Example 3 The walnut kernel raw material is subjected to microwave drying at a temperature of 75, dried to a moisture content of 8%, and a crushing particle size of 50. After the pretreated walnuts are loaded, they are hoisted into the extraction kettle, and the equipment is adjusted to the start state. After the extraction temperature reaches the conditions, the pressure pump is started, and the extraction pressure, extraction temperature, separation pressure, separation temperature, extraction time, extraction flow rate, and extraction of the walnut kernel are set to 36MPa, 50℃, 16MPa, 45℃, 3.0h, and 2700kg / h, and the walnut kernel is extracted. After the extracted material has been extracted for 7.0h and the extracted walnut oil output is ≤0.5kg, the pressure pump circulation is stopped, the machine is shut down for pressure leveling, and the pressure leveling speed is controlled to be 0.001-0.10MPa / s. After the pressure of the extraction kettle is consistent with that of the intermediate storage tank, the system is adjusted to the recovery state and the recovery operation is started. After the pressure of the extraction kettle is 0-0.2MPa, the recovery system is closed and the extraction kettle is opened to empty for pressure relief.

[0018] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

[0019] The above-mentioned extraction kettle and intermediate storage tank are both prior art and are conventional models in the field.

[0020] The following table 1 is the extraction record table of Example 1:

[0021] Table 1 The following table 2 is the extraction record table of Example 2:

[0022] Table 2 The following table 3 is the extraction record table of Example 3:

[0023] Table 3 The following table 4 is the extraction record table of comparative example 1:

[0024] Table 4 The following table 5 is the extraction record table of comparative example 2:

[0025] Table 5 The following table 6 is the extraction record table of comparative example 3:

[0026] Table 6 The following table 7 is a general comparison of the extraction record table of the embodiment and the extraction record table of the comparative example:

[0027] Table 7 As can be seen from Table 7, the difference between the process for extracting walnut oil by the present invention and the conventional extraction method is that the present invention first reduces the pressure for extraction after a certain period of extraction, and then increases the pressure and reduces the flow rate for extraction after a certain period of extraction, while the conventional extraction method is a one-time constant pressure extraction; the extraction time of the present invention and the extraction time after increasing the pressure and reducing the flow rate are obtained from the experiment. Compared with the conventional method, the extraction time is reduced by nearly half, and the recovery time is also reduced, thereby reducing the power consumption of the equipment and the production cost.

[0028] The protection scope of the present invention is not limited to the technical solutions disclosed in the specific implementation methods. Any modifications, equivalent replacements, improvements, etc. made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A process for supercritical extraction of walnut oil, characterized in that: The steps include: pre-treating a walnut kernel raw material, loading the pre-treated walnuts, hoisting them into an extraction kettle, performing supercritical CO2 fluid extraction on the walnut kernels, and after extraction for 3-4 hours, reducing the frequency of a pressure pump to perform supercritical CO2 fluid pressure reduction extraction. After extraction time of 0.5-1 hour, performing pressure-raising and flow-reducing extraction until the extracted oil is less than or equal to 0.5kg, stopping the circulation of the pressure pump, shutting down the machine for pressure equalization, and adjusting the system to a recovery state after the pressure of the extraction kettle is consistent with that of an intermediate storage tank, starting a recovery operation, and after the pressure of the extraction kettle is 0-0.2MPa, closing the recovery system, and opening the extraction kettle to empty and release the pressure.

2. A process for supercritical extraction of walnut oil according to claim 1, characterized in that: The walnut kernel raw material pretreatment includes microwave drying and crushing; the microwave temperature in the microwave drying is 65-75° C., and the moisture content is dried to 5%-10%; the crushing particle size is 30-60 mesh.

3. A process for supercritical extraction of walnut oil according to claim 1, characterized in that: The extraction pressure of the walnut kernel supercritical CO2 fluid extraction is 25-55MPa, the extraction temperature is 40-50°C, the separation pressure is 6-18MPa, the separation temperature is 38-50°C, the extraction time is 3-4h, and the extraction flow rate is 2500-2700kg / h.

4. A process for supercritical extraction of walnut oil according to claim 1, characterized in that: The extraction pressure of the walnut kernel supercritical CO2 fluid decompression extraction is 10-18MPa, the extraction temperature is 38-50°C, the separation pressure is 6-18MPa, the separation temperature is 35-50°C, the extraction time is 0.5-1h, and the extraction flow rate is 2500-2700kg / h.

5. A process for supercritical extraction of walnut oil according to claim 1, characterized in that: The extraction pressure of the walnut kernel supercritical CO2 fluid boosting and reducing flow rate extraction is 25-55MPa, the extraction temperature is 40-50°C, the separation pressure is 6-18MPa, the separation temperature is 38-50°C, the extraction time is 1-2h, and the extraction flow rate is 1000-1800kg / h, until the extracted oil is ≤0.5kg.

6. The process for supercritical extraction of walnut oil according to claim 1, characterized in that: The shutdown and leveling pressure controls the leveling pressure speed to be 0.001-0.10MPa / s.

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