Extraction process of natural plant essential oil

Abstract

The invention relates to the technical field of extraction of plant essential oil, in particular to an extraction process of natural plant essential oil, which comprises the following steps: obtaining a flowering flower top of a natural plant, cutting and separating the flower top, and then separating again through a screen to obtain petals for later use; after petals are smashed, high-quality petals are screened out, cleaned with clear water and dried; placing the dried petal fragments in a distillation tower, and collecting various distillation monitoring data at each moment in the distillation tower; determining a distillation environment interference value at each moment; control parameters of a PI controller are adjusted, and the distillation temperature and the steam flow are adjusted in real time through the PI controller; after distillation is finished, essential oil in petal fragments is collected; and placing the collected essential oil in the distillation tower again, carrying out secondary rectification, and adjusting the distillation temperature and the steam flow to obtain the extracted plant essential oil. The method improves the extraction rate of the high-quality plant essential oil.

Description

Technical Field

[0001] The present application relates to the technical field of plant essential oil extraction, and in particular to a process for extracting natural plant essential oil. Background Art

[0002] Natural plant essential oil extraction is a process of concentrating the aroma and active ingredients of plants into essential oils. These essential oils are widely used in natural health, personal care, beauty, household cleaning, etc. Through essential oil extraction, we can make full use of natural plant resources and reduce dependence on chemical synthetic products. The extraction of many plant essential oils does not require excessive damage to the environment. Compared with industrial chemical products, the collection of natural essential oils is often more sustainable.

[0003] At present, steam distillation is a commonly used method for extracting natural plant essential oils. Steam distillation is generally applicable to the extraction of most plant essential oils. However, during the distillation process, the actual distillation temperature and gas flow rate are prone to fluctuations due to the interference of the stability of the distillation environment. If the temperature is too high or too low continuously, or the gas flow rate fluctuates too much, it may cause the essential oil components to be destroyed or the extraction to be insufficient, which will have an adverse effect on the extraction quality of natural plant essential oils. Summary of the invention

[0004] In order to solve the above technical problems, the present application provides a natural plant essential oil extraction process to solve the existing problems.

[0005] The extraction process of a natural plant essential oil in the present application adopts the following technical scheme:

[0006] An embodiment of the present application provides a process for extracting natural plant essential oils, the process comprising the following steps:

[0007] (1) obtaining the tops of flowers of natural plants that are in bloom, cutting and separating the tops of the flowers, and separating them again through a sieve to obtain spare petals;

[0008] (2) After the petals are crushed, the high-quality petals are selected, and they are washed with clean water and dried;

[0009] (3) placing the dried petal fragments in a distillation tower, and adjusting the distillation temperature and steam flow rate in real time during the distillation process, specifically comprising:

[0010] (3.1) Collect various distillation monitoring data at each time in the distillation tower;

[0011] (3.2) analyzing the distribution of the differences between various types of distillation monitoring data and preset standard data before each moment and the significance of the differences over time, and determining the deviation response coefficients of various types of distillation monitoring data at each moment; and combining the deviation response coefficients of all types of distillation monitoring data at each moment into a deviation response sequence at each moment;

[0012] (3.3) Based on the measured distance between the deviation response sequence of each moment and the historical moment, as well as the time difference, the deviation characteristic value of each moment is determined; the deviation response sequence of each moment and all previous moments constitutes the deviation response matrix of each moment, and the difference in linear independence of the deviation response matrix of each moment and the historical moment, as well as the trend of the deviation characteristic values ​​of all moments before each moment, is analyzed to determine the distillation environment interference value of each moment;

[0013] (3.4) adjusting the control parameters of the PI controller based on the distillation environment interference value, and using the PI controller to adjust the distillation temperature and steam flow in real time;

[0014] (4) After the distillation is completed, the essential oil in the petal fragments is collected;

[0015] (5) The collected essential oil is placed in a distillation tower again for secondary distillation, and the distillation temperature and steam flow rate are adjusted in the same steps as step (3) to obtain the extracted plant essential oil.

[0016] In one embodiment, the sieve has a pore size of 23 mm.

[0017] In one embodiment, the high-quality petals are screened by using a 20-40 mesh vibrating screen.

[0018] In one embodiment, the cleaning time is 5 to 10 minutes.

[0019] In one embodiment, the drying temperature is less than or equal to 40°C.

[0020] In one embodiment, the distillation monitoring data includes the temperature, pressure and steam flow rate in the distillation tower, wherein during the distillation process of step (3), the temperature is 100-120°C, the pressure is 0.2-0.5 MPa, the steam flow rate is 4-5 L / min, and the distillation time is 30-60 min.

[0021] In one embodiment, determining the deviation response coefficient includes:

[0022] The difference between each type of distillation monitoring data at each moment and the preset standard data is recorded as the first difference, and the first difference between each type of distillation monitoring data at each moment and all previous moments is used as the input of the entropy weight method to obtain the relative weight of each type of distillation monitoring data at each moment;

[0023] The mean of the first difference at each time and all previous times of each type of distillation monitoring data is calculated, and the deviation response coefficient is the product of the relative weight and the mean.

[0024] In one embodiment, determining the deviation characteristic value includes:

[0025] For each moment and any historical moment, the time difference is taken as the exponent of an exponential function with a natural constant as the base, and the ratio of the metric distance to the calculation result of the exponential function is calculated, and the deviation characteristic value is the average of the ratios of each moment and all historical moments.

[0026] In one embodiment, the determination of the distillation environment interference value includes:

[0027] The average value of the difference in rank of the deviation response matrix at each moment and all previous moments is calculated to obtain the trend statistic of the deviation characteristic value at each moment and all previous moments, and the distillation environment interference value is the product of the average value and the trend statistic.

[0028] In one embodiment, adjusting the control parameters of the PI controller based on the distillation environment interference value includes:

[0029] The average of the normalized values ​​of the distillation environment interference values ​​at all moments before each moment is calculated and recorded as the adjustment threshold at each moment. If the normalized value of the distillation environment interference value at each moment is greater than or equal to the adjustment threshold, the control parameters of the PI controller are adjusted, specifically:

[0030] Calculate the multiplication result of the normalized value of the distillation environment interference value at each moment and the initial integral control parameter of the PI controller, the integral control parameter adjusted at each moment of the PI controller is the sum of the initial integral control parameter and the multiplication result;

[0031] Otherwise, the control parameters of the PI controller are not adjusted.

[0032] This application has at least the following beneficial effects:

[0033] The present application obtains the tops of flowers of natural plants that are in bloom, cuts and separates the tops, and separates them again through a sieve to obtain spare petals; crushes the petals, selects high-quality petals, and washes and dries them with clean water; places the dried petal fragments in a distillation tower, and adjusts the distillation temperature and steam flow rate in real time during the distillation process, specifically including:

[0034] Collect various types of distillation monitoring data at each moment in the distillation tower; analyze the distribution of the differences between various types of distillation monitoring data and preset standard data before each moment over time, as well as the significance of the differences, and determine the deviation response coefficients of various types of distillation monitoring data at each moment; the deviation response coefficient reflects the associated change relationship of the continuous response of various types of distillation monitoring data, and highlights the significant characteristics of the control deviation caused by the continuous influence of various types of distillation monitoring data; the deviation response coefficients of all types of distillation monitoring data at each moment are combined into a deviation response sequence at each moment; based on the measured distance and time difference between the deviation response sequence at each moment and the historical moment, the deviation characteristic value at each moment is determined; the deviation characteristic value reflects the severity of the influence of continuous deviation on the distillation process, and improves the accuracy of continuous deviation extraction in the distillation process; the deviation response sequence of each moment and all previous moments constitutes the deviation response matrix at each moment, and the linear relationship between the deviation response matrix at each moment and the historical moment is analyzed. The difference in independence of the distillation environment and the trend of the deviation characteristic values ​​of all moments before each moment are used to determine the distillation environment interference value at each moment; the distillation environment interference value reflects the linear difference of the monitoring data in the distillation process and the trend of the control deviation, and reflects the influence of the change of environmental stability and the influence of the continuous change of the state on the distillation process, thereby improving the comprehensiveness and accuracy of the determination of the continuous deviation of the distillation temperature and the steam flow rate in the distillation process; based on the distillation environment interference value, the control parameters of the PI controller are adjusted, and the distillation temperature and the steam flow rate are adjusted in real time by using the PI controller; the stability of the distillation temperature and the steam flow rate in the distillation process is improved; after the distillation is completed, the essential oil in the petal fragments is collected; the collected essential oil is placed in the distillation tower again for secondary distillation, and the distillation temperature and the steam flow rate are adjusted by the same steps as step (3) to obtain the extracted essential oil, thereby finally improving the extraction rate of high-quality plant essential oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 A flowchart of the steps of a natural plant essential oil extraction process provided in this application;

[0037] Figure 2 This is the flow chart for distillation temperature and steam flow control. DETAILED DESCRIPTION

[0038] In order to further explain the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the following is a detailed description of the extraction process of a natural plant essential oil proposed in the present application, its specific implementation, structure, characteristics and effects, in conjunction with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0039] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0040] The specific scheme of the extraction process of a natural plant essential oil provided by the present application is described in detail below with reference to the accompanying drawings.

[0041] Example 1

[0042] Example 1 provides a natural plant essential oil extraction process. For the step flow chart, please refer to Figure 1 , the specific process steps are as follows:

[0043] (1) Select the flower tops of natural plants that are in bloom, cut and separate them, and remove the petals except the flower tops, leaving only the flower tops; separate the petals of the retained flower tops through a sieve, the aperture of the sieve in this embodiment is set to 23 mm to ensure effective separation of impurities and the flower tops, record the collected flower tops as spare petals, and temporarily store the spare petals in a well-ventilated and clean container to avoid contamination and deterioration.

[0044] (2) The spare petals are crushed by a professional crusher, and the crushed petals are screened through a 20-mesh vibrating screen to obtain high-quality petals, and the defective petals are removed. The screened high-quality petals are washed with purified water, and the washing method is gentle stirring and washing for 5 minutes to remove surface dust, impurities and possible residual pesticides and other harmful substances. The washed petals are dried to constant weight using low-temperature drying equipment at a drying temperature of 35°C to prevent the effective ingredients in the petals from being destroyed by heat.

[0045] (3) placing the dried petal fragments in a distillation tower, setting the distillation temperature in the distillation process to 100° C., the steam flow rate to 4 L / min, the pressure to 0.2 MPa, and the distillation time to 30 min; due to the evaporation and condensation process of distillation, the temperature and steam flow rate in the distillation process will fluctuate, and since the distillation temperature and steam flow rate have a great influence on the quality of the extracted essential oil, therefore, the distillation temperature and steam flow rate in the distillation process are controlled to keep them stable, and the specific control process is as follows:

[0046] Step (3.1), collecting various types of distillation monitoring data at each time in the distillation tower and performing preprocessing.

[0047] A temperature sensor, a flow sensor and a pressure sensor are installed in the distillation tower to collect the distillation temperature, steam flow rate and pressure at each moment in the distillation process in real time. The distillation temperature, steam flow rate and pressure are all recorded as distillation monitoring data. In this embodiment, the distillation temperature, steam flow rate and pressure are all collected synchronously, and the collection time interval is 1s. The implementer can set it according to the actual situation, and this embodiment does not limit it here.

[0048] Since sensor data collected during the distillation process may be affected by equipment operation and may result in noise interference in the collected data, the various types of distillation monitoring data collected are used as input, and a Wiener filter is used to perform noise reduction processing on the various types of distillation monitoring data. The specific noise reduction process of the Wiener filter is an existing well-known technology and will not be described in detail. The implementer can choose other existing feasible filtering algorithms according to actual conditions, and this embodiment is not limited here.

[0049] Step (3.2), analyzing the distribution of the differences between various types of distillation monitoring data and preset standard data before each moment over time, as well as the significance of the differences, to determine the deviation response coefficients of various types of distillation monitoring data at each moment; and combining the deviation response coefficients of all types of distillation monitoring data at each moment into a deviation response sequence at each moment.

[0050] Normally, during the extraction process of natural plant essential oils, the distillation temperature and steam flow rate will fluctuate due to environmental stability deviations and changes in the state of the distillation instruments used. Fluctuations over a longer time range may cause the distillation temperature deviation to tend to be higher or lower, thereby affecting the size of the steam flow rate and pressure. It should be noted that if there is a continuous state change during the distillation process, the range of control deviations in the distillation process will increase, resulting in lower quality of the natural plant essential oils obtained. Therefore, during the distillation process, it is necessary to analyze the existing continuous influence characteristics through the response change characteristics between the distillation monitoring data, and extract the deviation characteristics caused by continuous fluctuations based on the analysis results.

[0051] Based on the above analysis, the control deviation in the distillation process is judged and analyzed according to the changes in the environmental stability of the distillation instrument and the interference characteristics of the state changes. If the control error increases due to the influence of interference factors, it is the result of the interference influence over a longer time range. Therefore, the distillation deviation characteristics of different stages are analyzed based on the distillation monitoring data collected during the distillation process.

[0052] Considering that the feedback monitoring adjustment in the actual distillation process is a real-time adjustment process, if there is a continuous interference effect, it may cause a large error in its real-time adjustment at the current moment; and the traditional feedback control process does not judge and analyze the impact of the continuous change of the distillation process state, which leads to periodic differences in the deviation of the automatic control adjustment of the distillation process.

[0053] Therefore, based on the real-time collected denoised distillation monitoring data, the continuous fluctuation change characteristics of the distillation monitoring at all moments before each moment are judged and analyzed; specifically, the difference between each type of distillation monitoring data and the set value at each moment is calculated and recorded as the first difference; the first difference of each type of distillation monitoring data at each moment and all moments before it is combined into a difference sequence of each type of distillation monitoring data at each moment in chronological order, and the difference sequence is used to reflect the response state of the control deviation of the distillation monitoring data in the chronological order up to each moment; wherein, for the set value, it is specifically the distillation temperature of 100°C, the steam flow rate of 4L / min, and the pressure of 0.2MPa in step (3); the difference represents the degree of difference between two variables, and the calculation method of the first difference in this embodiment is the difference between each type of distillation monitoring data and the set value.

[0054] Furthermore, in order to accurately analyze the differences in the continuous changes in the control deviation response state, the difference sequences of various types of distillation monitoring data at various moments are taken as input, and the entropy weight method is used to obtain the relative weights of various types of distillation monitoring data at various moments. The larger the relative weight, the more significant the response change of the distillation monitoring data up to that moment. For various types of distillation monitoring data, the mean of all elements in the difference sequence at each moment is calculated, and the product of the mean and the corresponding relative weight is used as the deviation response coefficient of various types of distillation monitoring data at each moment. The deviation response coefficient analyzes the correlation and change relationship of the continuous response of various types of distillation monitoring data during the distillation process, and highlights the significant characteristics of the control deviation caused by the continuous influence of various types of distillation monitoring data.

[0055] Furthermore, the deviation response coefficients of all types of distillation monitoring data at each moment are combined into a deviation response sequence at each moment, wherein the arrangement order of all types of distillation monitoring data in the deviation response sequence is distillation temperature, steam flow, and pressure.

[0056] Step (3.3) determines the deviation characteristic value of each moment based on the measured distance between the deviation response sequence of each moment and the historical moment, as well as the time difference; constructs the deviation response matrix of each moment by combining the deviation response sequence of each moment and all the moments before it, analyzes the difference in linear independence of the deviation response matrix of each moment and the historical moment, as well as the trend of the deviation characteristic values ​​of all the moments before each moment, and determines the distillation environment interference value of each moment.

[0057] First, based on the deviation response sequence at each moment, the deviation characteristic value at each moment is calculated. The specific calculation method is:

[0058] In the formula, h x represents the deviation characteristic value at the xth moment in the distillation process, n x is the number of historical moments before the xth moment in the distillation process, k x is the deviation response sequence at the xth moment in the distillation process, k y is the deviation response sequence of the yth historical moment before the xth moment in the distillation process, md() represents the metric distance calculation function, t x is the xth moment in the distillation process, t y is the yth historical moment before the xth moment in the distillation process, t x -t y is the time interval between the xth moment and the yth historical moment, and exp() is an exponential function with a natural constant as the base to avoid the denominator being 0. In this embodiment, the metric distance calculation function adopts Manhattan distance, and the implementer can select other existing feasible metric distance calculation methods according to actual conditions, such as Euclidean distance, DTW distance, etc.

[0059] It should be understood that the characteristic deviation value h during the distillation process x The larger it is, the more seriously the distillation process is affected by the persistence deviation up to the xth moment.

[0060] Based on the above analysis, in the extraction process of natural plant essential oils, the more serious the characteristics of the distillation temperature being affected by the environmental stability and the continuous influence of the state change over a long period of time, the greater the difference in the control deviation response at different acquisition moments up to the current moment; further, in the distillation process, if it is not affected by continuous interference, then up to the current moment, the deviation responses between different moments are linearly related, therefore, for the deviation response sequence at each moment, take it as a column vector, take the deviation response sequence at each moment and all the moments before it as a column vector, and construct the deviation response matrix at each moment.

[0061] The rank of the deviation response matrix at each moment is used as the linear difference value of the stage deviation. The larger the linear difference value of the stage deviation is, the greater the difference in nonlinear correlation caused by the continuous interference at different moments in the distillation process is.

[0062] Based on the linear difference values ​​of stage deviations at different collection moments and the deviation characteristic values ​​during the distillation process, the continuous impact deviations at each moment are analyzed, and the distillation environment interference values ​​at each moment are calculated. The specific calculation method is:

[0063] In the formula, sx represents the distillation environment interference value at the xth moment in the distillation process, c x is the linear difference value of the stage deviation at the xth moment in the distillation process, c y is the linear difference value of the stage deviation before the xth moment in the distillation process, n x is the number of historical moments before the xth moment in the distillation process, p x It is the trend statistic of the deviation characteristic value at the xth moment and all previous moments in the distillation process.

[0064] It should be noted that the calculation of the trend statistic in this embodiment adopts the MK (Mann-Kendall) trend test algorithm. The MK trend test algorithm is an existing well-known technology. The implementer can choose other existing feasible trend test algorithms according to actual conditions, and this embodiment does not limit it here.

[0065] It should be understood that the distillation environment interference value s during the distillation process x The larger it is, the more significant the linear difference and control deviation trend characteristics of the monitoring data in the distillation process are up to the xth moment, that is, the more serious the impact of changes in environmental stability and the persistence of state changes is.

[0066] Step (3.4), adjusting the control parameters of the PI controller based on the distillation environment interference value, and using the PI controller to adjust the distillation temperature and steam flow rate in real time during the distillation process.

[0067] During the distillation process of natural plant essential oil extraction, the Softmax function is used to obtain the normalized results of the distillation environment interference values ​​at all previous moments up to the current moment, and the average of all the normalized results is used as the adjustment threshold of the fluctuation deviation response at the current moment in the distillation process. Specifically, if the normalized result of the distillation environment interference value at the current moment is greater than or equal to the adjustment threshold, it means that at the current moment, the control deviation is greatly affected by the continuous interference, which may cause a large control deviation. At the current moment, the parameters of the controller in the distillation process need to be adjusted. Otherwise, the parameters of the controller in the distillation process are not adjusted at the current moment.

[0068] It should be noted that this embodiment only provides a method for obtaining the normalized result of the distillation environment interference value, and the implementer can choose other existing feasible normalization methods at will; in order to ensure the accuracy of the parameter adjustment of the controller during the distillation process, this embodiment does not adjust the parameters of the controller in the first 10 moments at the beginning of the distillation process, so that there is sufficient historical data support for subsequent parameter adjustments; the controller in this embodiment is a PI controller, wherein the initial value of the control parameter of the PI controller is determined by the attenuation curve method, which is an existing well-known technology, and the specific process will not be repeated.

[0069] Specifically, if the normalized result of the current distillation environment interference value is greater than or equal to the adjustment threshold, in order to reduce the error in the control process, the integral control parameter of the PI controller needs to be adjusted. The specific adjustment formula is: x =I o +I o ×S x Where, I x I represents the integral control parameter of the PI controller adjusted at the xth moment in the distillation process; o Represents the initial integral control parameter of the PI controller; S x Represents the normalized result of the distillation environment interference value at the x-th moment in the distillation process.

[0070] Therefore, during the distillation process, when the distillation temperature deviates from the set value, the adjusted PI controller automatically adjusts the power of the heating device to control the distillation temperature. When the steam flow deviates from the set value, the adjusted PI controller automatically adjusts the opening of the steam pipe valve to ensure the stability of the steam flow. In this way, the distillation temperature and steam flow can be kept constant during the distillation process to ensure the quality of the natural plant essential oil extraction. Among them, the PI controller is an existing well-known technology, and the specific process is not described in detail. The distillation temperature and steam flow control flow chart is as follows Figure 2 shown.

[0071] (4) After the distillation is completed, the cooling system automatically starts and uses circulating water cooling to quickly cool the distilled steam into liquid. The essential oil distilled from the petal fragments is obtained through an oil-water separator and collected in a pre-sterilized glass container.

[0072] (5) placing the essential oil obtained in step (4) in a distillation tower again for secondary distillation, setting the distillation temperature to 120° C., the steam flow rate to 4 L / min, the pressure to 0.2 MPa, and the distillation time to 30 min, and adopting the same control method for the distillation temperature and steam flow rate as in the distillation process of step (3) to control the distillation temperature and steam flow rate in the secondary distillation process, so as to ensure that the essential oil is separated and purified under optimal conditions, and obtain high-quality plant essential oil.

[0073] Example 2

[0074] Example 2 provides a natural plant essential oil extraction process. For the step flow chart, please refer to Figure 1 , the specific process steps are as follows:

[0075] (1) Select the flower tops of natural plants that are in bloom, cut and separate them, and remove the petals except the flower tops, leaving only the flower tops; separate the petals of the retained flower tops through a sieve, the aperture of the sieve in this embodiment is set to 23 mm to ensure effective separation of impurities and the flower tops, record the collected flower tops as spare petals, and temporarily store the spare petals in a well-ventilated and clean container to avoid contamination and deterioration.

[0076] (2) The spare petals are crushed by a professional crusher, and the crushed petals are screened through a 30-mesh vibrating screen to obtain high-quality petals, and the defective petals are removed. The screened high-quality petals are washed with purified water, and the washing method is gentle stirring and washing for 8 minutes to remove surface dust, impurities and possible residual pesticides and other harmful substances. The washed petals are dried to constant weight using low-temperature drying equipment at a drying temperature of 36°C to prevent the effective ingredients in the petals from being destroyed by heat.

[0077] (3) placing the dried petal fragments in a distillation tower, setting the distillation temperature during the distillation process to 110° C., the steam flow rate to 4 L / min, the pressure to 0.4 MPa, and the distillation time to 45 min; due to the evaporation and condensation process of distillation, the temperature and steam flow rate during the distillation process will fluctuate, and since the distillation temperature and steam flow rate have a great influence on the quality of the extracted essential oil, therefore, the distillation temperature and steam flow rate during the distillation process are controlled to keep them stable, and the specific control process adopts the same steps as in Example 1.

[0078] (4) After the distillation is completed, the cooling system automatically starts and uses circulating water cooling to quickly cool the distilled steam into liquid. The essential oil distilled from the petal fragments is obtained through an oil-water separator and collected in a pre-sterilized glass container.

[0079] (5) placing the essential oil obtained in step (4) in a distillation tower again for secondary distillation, setting the distillation temperature to 140° C., the steam flow rate to 4 L / min, the pressure to 0.4 MPa, and the distillation time to 45 min, and adopting the same control method for the distillation temperature and steam flow rate as in the distillation process of step (3) to control the distillation temperature and steam flow rate in the secondary distillation process, so as to ensure that the essential oil is separated and purified under optimal conditions, and obtain high-quality plant essential oil.

[0080] Example 3

[0081] Example 3 provides a natural plant essential oil extraction process. For the step flow chart, please refer to Figure 1 , the specific process steps are as follows:

[0082] (1) Select the flower tops of natural plants that are in bloom, cut and separate them, and remove the petals except the flower tops, leaving only the flower tops; separate the petals of the retained flower tops through a sieve, the aperture of the sieve in this embodiment is set to 23 mm to ensure effective separation of impurities and the flower tops, record the collected flower tops as spare petals, and temporarily store the spare petals in a well-ventilated and clean container to avoid contamination and deterioration.

[0083] (2) The spare petals are crushed by a professional crusher, and the crushed petals are screened through a 40-mesh vibrating screen to obtain high-quality petals, and the defective petals are removed. The screened high-quality petals are washed with purified water, and the washing method is gentle stirring and washing for 10 minutes to remove surface dust, impurities and possible residual pesticides and other harmful substances. The washed petals are dried to constant weight using low-temperature drying equipment at a drying temperature of 40°C to prevent the effective ingredients in the petals from being destroyed by heat.

[0084] (3) placing the dried petal fragments in a distillation tower, setting the distillation temperature during the distillation process to 120° C., the steam flow rate to 5 L / min, the pressure to 0.5 MPa, and the distillation time to 60 min; due to the evaporation and condensation process of distillation, the temperature and steam flow rate during the distillation process will fluctuate, and since the distillation temperature and steam flow rate have a great influence on the quality of the extracted essential oil, therefore, the distillation temperature and steam flow rate during the distillation process are controlled to keep them stable, and the specific control process adopts the same steps as in Example 1.

[0085] (4) After the distillation is completed, the cooling system automatically starts and uses circulating water cooling to quickly cool the distilled steam into liquid. The essential oil distilled from the petal fragments is obtained through an oil-water separator and collected in a pre-sterilized glass container.

[0086] (5) placing the essential oil obtained in step (4) in a distillation tower again for secondary distillation, setting the distillation temperature to 150° C., the steam flow rate to 5 L / min, the pressure to 0.5 MPa, and the distillation time to 60 min, and adopting the same control method for the distillation temperature and steam flow rate as in the distillation process of step (3) to control the distillation temperature and steam flow rate in the secondary distillation process, so as to ensure that the essential oil is separated and purified under optimal conditions, and obtain high-quality plant essential oil.

[0087] For Example 1 of the present application, the distillation temperature and steam flow rate in the distillation process of plant essential oil extraction are not adjusted, and the remaining steps and parameters are exactly the same as those in Example 1 to obtain the extracted plant essential oil, as Comparative Example 1, wherein the distillation process includes step (3) distillation and step (5) secondary distillation.

[0088] For Example 2 of the present application, the distillation temperature and steam flow rate in the distillation process of plant essential oil extraction are not adjusted, and the remaining steps and parameters are exactly the same as those in Example 2 to obtain the extracted plant essential oil, as Comparative Example 2, wherein the distillation process includes step (3) distillation and step (5) secondary distillation.

[0089] For Example 3 of the present application, the distillation temperature and steam flow rate in the distillation process of plant essential oil extraction are not adjusted, and the remaining steps and parameters are exactly the same as those in Example 3 to obtain the extracted plant essential oil as Comparative Example 3, wherein the distillation process includes step (3) distillation and step (5) secondary distillation.

[0090] The extraction rates of high-quality plant essential oils of Example 1, Example 2, Example 3, and Comparative Example 1, Comparative Example 2, and Comparative Example 3 were statistically analyzed, and the results are shown in Table 1.

[0091] Table 1 Comparison of extraction rates of high-quality plant essential oils

[0092] Implementation High-quality plant essential oil extraction rate (%) Example 1 55 Example 2 52 Example 3 54 Comparative Example 1 49 Comparative Example 2 45 Comparative Example 3 42

[0093] As can be seen from Table 1, the embodiment of the present application improves the extraction rate of high-quality plant essential oils by adjusting the distillation temperature and steam flow rate during the distillation process.

[0094] It should be noted that the above sequence of the embodiments of the present application is for description only and does not represent the advantages and disadvantages of the embodiments. The above is a description of a specific embodiment of this specification. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0095] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0096] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Modifications to the technical solutions recorded in the aforementioned embodiments, or equivalent replacement of some of the technical features therein, do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A process for extracting natural plant essential oils, characterized in that: The process includes the following steps: (1) obtaining the tops of flowers of natural plants that are in bloom, cutting and separating the tops of the flowers, and separating them again through a sieve to obtain spare petals; (2) After the petals are crushed, the high-quality petals are selected, and they are washed with clean water and dried; (3) placing the dried petal fragments in a distillation tower, and adjusting the distillation temperature and steam flow rate in real time during the distillation process, specifically comprising: (3.1) Collect various distillation monitoring data at each time in the distillation tower; (3.2) analyzing the distribution of the differences between various types of distillation monitoring data and preset standard data before each moment and the significance of the differences over time, and determining the deviation response coefficients of various types of distillation monitoring data at each moment; and combining the deviation response coefficients of all types of distillation monitoring data at each moment into a deviation response sequence at each moment; (3.3) Based on the measured distance between the deviation response sequence of each moment and the historical moment, as well as the time difference, the deviation characteristic value of each moment is determined; the deviation response sequence of each moment and all previous moments constitutes the deviation response matrix of each moment, and the difference in linear independence of the deviation response matrix of each moment and the historical moment, as well as the trend of the deviation characteristic values ​​of all moments before each moment, is analyzed to determine the distillation environment interference value of each moment; (3.4) adjusting the control parameters of the PI controller based on the distillation environment interference value, and using the PI controller to adjust the distillation temperature and steam flow in real time; (4) After the distillation is completed, the essential oil in the petal fragments is collected; (5) The collected essential oil is placed in a distillation tower again for secondary distillation, and the distillation temperature and steam flow rate are adjusted in the same steps as step (3) to obtain the extracted plant essential oil.

2. A process for extracting natural plant essential oils as claimed in claim 1, characterized in that: The aperture of the sieve is 23 mm.

3. A process for extracting natural plant essential oil as claimed in claim 1, characterized in that: The high-quality petals are screened out by using a 20-40 mesh vibrating screen.

4. A process for extracting natural plant essential oil as claimed in claim 1, characterized in that: The time for the clean water washing is 5 to 10 minutes.

5. A process for extracting natural plant essential oil as claimed in claim 1, characterized in that: The drying temperature is less than or equal to 40°C.

6. A process for extracting natural plant essential oil as claimed in claim 1, characterized in that: The distillation monitoring data includes the temperature, pressure and steam flow rate in the distillation tower, wherein during the distillation process of step (3), the temperature is 100-120°C, the pressure is 0.2-0.5 MPa, the steam flow rate is 4-5 L / min, and the distillation time is 30-60 min.

7. A process for extracting natural plant essential oil as claimed in claim 1, characterized in that: The determination of the deviation response coefficient includes: The difference between each type of distillation monitoring data at each moment and the preset standard data is recorded as the first difference, and the first difference between each type of distillation monitoring data at each moment and all previous moments is used as the input of the entropy weight method to obtain the relative weight of each type of distillation monitoring data at each moment; The mean of the first difference at each time and all previous times of each type of distillation monitoring data is calculated, and the deviation response coefficient is the product of the relative weight and the mean.

8. A process for extracting natural plant essential oil as claimed in claim 1, characterized in that: Determination of the deviation characteristic value includes: For each moment and any historical moment, the time difference is taken as the exponent of an exponential function with a natural constant as the base, and the ratio of the metric distance to the calculation result of the exponential function is calculated, and the deviation characteristic value is the average of the ratios of each moment and all historical moments.

9. A process for extracting natural plant essential oil as claimed in claim 1, characterized in that: Determination of the distillation environment interference value includes: The average value of the difference in rank of the deviation response matrix at each moment and all previous moments is calculated to obtain the trend statistic of the deviation characteristic value at each moment and all previous moments, and the distillation environment interference value is the product of the average value and the trend statistic.

10. A process for extracting natural plant essential oil according to claim 1, characterized in that: The adjusting the control parameters of the PI controller based on the distillation environment interference value comprises: The average of the normalized values ​​of the distillation environment interference values ​​at all moments before each moment is calculated and recorded as the adjustment threshold at each moment. If the normalized value of the distillation environment interference value at each moment is greater than or equal to the adjustment threshold, the control parameters of the PI controller are adjusted, specifically: Calculate the multiplication result of the normalized value of the distillation environment interference value at each moment and the initial integral control parameter of the PI controller, the integral control parameter adjusted at each moment of the PI controller is the sum of the initial integral control parameter and the multiplication result; Otherwise, the control parameters of the PI controller are not adjusted.

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