Process and apparatus for separating high-grade fatty alcohol from rice bran wax by digital simulation and optimization assisted batch rectification

Abstract

The present application relates to a kind of digital simulation and optimization auxiliary batch rectification separation process and device of high-grade fatty alcohol in rice bran wax;The present application high vacuum batch rectification technology separates and purifies high-grade fatty alcohol, uses single tower operation, equipment investment is small, operation is flexible, raw material is widely applicable, through simulation optimization auxiliary operation, mainly control reflux ratio and each fraction segment distillation amount, obtain the composition required for each fraction segment, realize on-demand production, by controlling the pressure difference between tower top and bottom, maintain the stable operation of rectification process, production process control is simple, and the automation and intelligent level is higher;Rectification column overhead condenser uses evaporation condenser, with water as evaporation medium to condense material, the boiling point of water is 100 DEG C, higher than the melting point of high-grade fatty alcohol, solve the problem of blockage caused by high-grade fatty alcohol crystallization due to high melting point.Equipment is simple, operation is flexible, raw material is widely applicable, and operation is simple and reliable.

Description

Technical Field

[0001] This invention belongs to the field of separating and purifying higher fatty alcohols from rice bran wax, specifically relating to a method for obtaining higher fatty alcohols of a desired purity from rice bran wax through digital simulation-optimized assisted high-vacuum batch distillation. In particular, it relates to a process and apparatus for digitally simulating and optimizing assisted batch distillation for separating higher fatty alcohols from rice bran wax. Background Technology

[0002] Rice bran wax, abundant in the bran of rice, is a natural plant wax, mostly appearing as a yellowish-brown solid. It is a non-toxic ester mixture composed of a series of higher fatty alcohols and higher fatty acids. After saponification, it yields a mixture of higher fatty alcohols, primarily docosanool, tetracosanool, hexacosanool, octacosanool, triacontanol, and tridocosanool. These higher fatty alcohols have melting points of 70-90℃. Docosanool is a recognized broad-spectrum antiviral drug and also has potential for treating mild thermal and chemical burns, showing broad application prospects. Tetracosanool, also known as creosote, can be used to improve blood sugar and has the potential to become a diabetes treatment drug. Hexacosanool, also known as beeswax alcohol, is commonly used as a nutritional supplement and is also effective in lowering and inhibiting serum and liver cholesterol. Octacosanool, also known as montanol, is an internationally recognized health-promoting ingredient with multiple benefits, including lowering blood lipids and cholesterol, anti-atherosclerosis, enhancing endurance, anti-fatigue, anti-inflammation, anticoagulation, improving sleep, and protecting the liver. Triacontanol, also known as bee pollen alcohol, is a novel natural plant growth regulator that promotes the growth of rice, wheat, and other plants. It also significantly improves the quality and yield of various crops, including cereals, sugar beets, shiitake mushroom mycelium, and water chestnuts. Furthermore, triacontanol possesses anti-cancer properties and inhibits vascular endothelial factor. When the content of each component in a mixture of different higher fatty alcohols reaches a certain proportion, the components exhibit synergistic effects, resulting in better physiological activity. A mixture of higher fatty alcohols with a specific composition can be obtained by mixing corresponding high-purity fatty alcohols; however, the separation cost of high-purity fatty alcohols is very high. If a suitable mixture of higher fatty alcohols can be directly obtained through rational and effective control of distillation, energy consumption and production costs can be significantly reduced.

[0003] Higher fatty alcohols can be obtained from rice bran wax through saponification, extraction, and purification. Currently, the distillation separation processes for higher fatty alcohols include molecular distillation, batch distillation, and continuous distillation. In Chinese patent 202011044372.6, molecular distillation is used to purify higher fatty alkanols, collecting fractions at 200℃ and a vacuum of 5 Pa. However, molecular distillation is a single-stage distillation process with low separation efficiency and high equipment investment and maintenance costs. Chinese patent 202010581184.0 uses batch distillation to produce specific fingerprint spectrum prilool (octacosanol). Multiple fractions are obtained through batch distillation, and then specific fractions are mixed to obtain prilool with a specific fingerprint spectrum. This process switches distillation sections based on the top temperature of the column, making it difficult to stably control the material content of each fraction, resulting in difficulties in preparing prilool with a specific fingerprint spectrum. Chinese Patent 202210635407.6 discloses a process for producing higher fatty alcohols via continuous distillation. This process employs multiple distillation columns, making the distillation operation and control relatively complex. Continuous distillation is suitable for processes with stable feedstock composition, but it is difficult to apply to processes where the feedstock composition varies significantly.

[0004] In summary, existing methods for purifying higher fatty alcohols have the following drawbacks:

[0005] 1) Existing technologies for separating higher fatty alcohols include molecular distillation, which has low separation efficiency; multi-tower continuous distillation, which has a narrow applicability and is difficult to achieve separation requirements when the raw material concentration varies greatly; and batch distillation, which is flexible and dynamic, with constantly changing concentrations, currently relies on experience to determine the switching of distillation segments by referring to the top temperature of the column and taking continuous samples. However, the higher fatty alcohols in rice bran wax are complex, and the content of each distillation segment is difficult to control stably, making it impossible to achieve customized production of distillation segments as needed.

[0006] 2) Existing technologies do not mention the problem that the high melting point of higher fatty alcohols can easily cause blockages in pipelines and tower top condensers, which can lead to abnormal shutdowns during operation. Summary of the Invention

[0007] To overcome the shortcomings of existing technologies, this invention aims to provide a method and apparatus for separating higher fatty alcohols by digital simulation optimization-assisted high vacuum distillation. It employs evaporation and condensation technology to solve the problem of condenser blockage, uses digital simulation optimization to obtain the reflux ratio and distillation rate of each fraction, and controls the reflux ratio and distillation rate to obtain the required concentration of each fraction. The apparatus has a high degree of automation and intelligence, is simple to operate, flexible to use, has a wide range of applicable raw materials, and is easy and reliable to operate.

[0008] This invention is achieved through the following technical solution:

[0009] A process for separating higher fatty alcohols by batch distillation with digital simulation optimization includes the following steps:

[0010] S1 uses digital simulation to optimize the reflux ratio and distillation rate of each fraction based on the composition, feed rate, and separation requirements of the higher fatty alcohol feedstock to be separated. During the calculation, the theoretical number of plates is determined based on the packing type and height of the distillation column, and the appropriate evaporation rate is determined based on the vacuum of the distillation system and the diameter of the distillation column. Through simulation optimization, operating parameters such as reflux ratio and distillation rate of each fraction that meet the separation requirements are obtained.

[0011] S2 Weigh the specified amount of high-grade fatty alcohol raw material and add it to the melting tank. Turn on the heating system of the melting tank to melt the raw material.

[0012] S3 activates the vacuum system to evacuate the system, reaching an absolute pressure of 80-100 Pa at the top of the column. Open the bottom valve of the feed tank to add the raw material liquid to the distillation kettle. Start the heating system in the distillation kettle to begin heating. The vapor generated by the material enters the evaporator-condenser through the distillation column. The evaporator-condenser tubes are filled with soft water. The material vapor flows inside the tubes, transferring heat to the soft water, causing it to vaporize. Simultaneously, the material vapor condenses and refluxes. Once reflux occurs at the top of the column, total reflux is implemented.

[0013] After the S4 total reflux is completed, the reflux ratio distributor is turned on, and the first fraction is collected according to the reflux ratio obtained by simulation optimization. The material collected from the top of the column enters the first receiving tank. When the material in the first receiving tank reaches the total amount calculated by simulation, the rectification of the first fraction section ends, and the material collection into the first receiving tank stops. According to the reflux ratio of the second fraction section obtained by simulation optimization, the material is discharged into the second receiving tank. When the material in the second receiving tank reaches the material amount calculated by simulation, the material discharge into the second receiving tank stops. Then, according to the reflux ratio of the third fraction section, the material is discharged into the third receiving tank, and so on, until the last fraction is discharged.

[0014] After the last fraction is collected from the bottom of the S5 column, close the top reflux distributor, open the bottom discharge valve of the distillation vessel, and release the residue into the residue tank; then, put the next batch of material from the feed tank into the distillation vessel for the next batch of distillation.

[0015] The process of separating higher fatty alcohols by digital simulation optimization assisted batch distillation includes step S1, in which digital simulation optimization calculations are performed based on the raw material composition and product requirements to obtain the reflux ratio R of each fraction that meets the product requirements. j and the distillate D of each fraction j Based on the product composition requirements of each fraction, the optimization objective function is determined as follows:

[0016]

[0017] in:

[0018] OF - objective function;

[0019] —The concentration of the i-th component in the j-th fraction that is expected to be achieved in the product requirements;

[0020] --The concentration of the i-th component in the j-th fraction segment calculated by simulation;

[0021] C - Total number of components; q - Total number of fractions;

[0022] - The product requirements specify the range of component k in the m fraction, where a is the lower limit and b is the upper limit. If only the lower limit exists, then the lower limit is a and b = 1. If only the upper limit exists, then a = 0 and the upper limit is b.

[0023] —The weighting factor of component i in the j-th fraction of the product requirements is 0 if the content of component i is not required in the product or if there is a range requirement, and 1 otherwise.

[0024] This invention relates to a digital simulation-optimized assisted batch distillation process for separating higher fatty alcohols. The apparatus includes a distillation kettle, a feed tank, a distillation column, an evaporator-condenser, a medium condenser, a reflux distributor, a collector, a receiving tank, a buffer tank, a vacuum pump, a computer, and a residue tank. The distillation column has a reflux distributor at its top, and an evaporator-condenser above it for condensing the higher fatty alcohol vapors. The evaporator-condenser is connected between its tubes to the medium condenser, which cools the medium. The distillation column has a distillation kettle at its bottom, and a feed tank above it for melting the feedstock. The bottom of the distillation kettle is connected to the residue tank for collecting the residue. The top of the distillation column is connected to a receiving tank group via the reflux distributor for collecting different fractions separated at the top. Two collectors are connected above the evaporator-condenser to collect the material vapors that the evaporator-condenser fails to condense. The collected material flows into a buffer tank connected below the collectors. The top of the buffer tank is connected to the vacuum pump to provide a vacuum for the system. The distillation process is optimized and controlled by computer through digital simulation.

[0025] The aforementioned digital simulation-optimized assisted intermittent distillation separation device for higher fatty alcohols uses soft water as the medium in the evaporator-condenser. The steam from the top of the evaporator is condensed by water evaporation, and the water vapor is cooled into liquid water by the medium condenser and then recycled back to the evaporator-condenser.

[0026] The aforementioned digital simulation-optimized assisted intermittent distillation separation device for higher fatty alcohols uses two traps that are switched between. After processing 5-10 batches of material, the trap is switched. The material in the trap, which is isolated from the system, is melted by steam generated by an evaporator condenser and discharged from the trap.

[0027] The digital simulation-optimized assisted intermittent distillation process of the present invention for separating higher fatty alcohols is applied to the purification of higher fatty alcohols in rice bran wax.

[0028] The specific explanation is as follows:

[0029] A method for separating higher fatty alcohols using digital simulation optimization-assisted high-vacuum distillation is disclosed. This method employs a distillation apparatus for intermittent distillation under high vacuum. The distillation apparatus includes a distillation column, a distillation kettle, an evaporator-condenser connected to the top of the distillation column, a medium condenser, a collector, a reflux ratio distributor, a storage tank, a vacuum buffer tank, a feed tank, and a vacuum pump. The distillation process is simulated and optimized by computer, and the distillation apparatus is computer-controlled. Higher fatty alcohols have very high boiling points at room temperature, therefore high-vacuum distillation is used to lower the operating temperature. Higher fatty alcohols have high melting points (70-90℃), so an evaporator-condenser is used to condense the vapor from the top of the column using the evaporator-condenser, preventing condenser blockage. After the water in the evaporator-condenser vaporizes, the water vapor enters the medium condenser, is cooled by cooling water, and then circulates back to the evaporator-condenser. Before starting the distillation process, digital simulation optimization calculations are performed based on the raw material composition and product requirements to obtain the reflux ratio and distillate yield of each fraction that meet the product requirements. The distillation operation and control are then performed based on the calculation results. The simulation optimization method is as follows:

[0030] Based on the product composition requirements of each fraction, the optimization objective function is determined as follows:

[0031]

[0032] In the above objective function:

[0033] OF - Objective Function. The smaller the OF, the closer it is to the product requirements.

[0034] —The concentration of the i-th component in the j-th fraction segment expected to be achieved in the product requirements; RD (RequestedData) refers to the data in the product requirements.

[0035] --The concentration of the i-th component in the j-th fraction of the simulation calculation; CD (Calculated Data) refers to the calculated data.

[0036] C - Total number of components; q - Total number of fractions;

[0037] - The product requirements specify the range of component k in the m fraction. a is the lower limit and b is the upper limit. If only the lower limit exists, then the lower limit is a and b = 1. If only the upper limit exists, then a = 0 and the upper limit is b.

[0038] —The weighting factor of component i in the j-th fraction of the product requirements is 0 if the content of component i is not required in the product or if there is a range requirement, and 1 otherwise.

[0039] The optimized process control variable is the reflux ratio R of each fraction. j and distillation volume D j .

[0040] For a given distillation column, given the column diameter, height, and packing type, once the operating pressure P is determined, the theoretical plate number N, the suitable evaporation rate V, and the pressure differential ΔP and liquid holdup H can be determined. Furthermore, the feed rate F and feed composition x... F,i It is known. Under the given conditions above, the reflux ratio R of each fraction is further given. j and distillation volume D j A single initial value is sufficient for simulating a batch distillation process. The reflux ratio R for each fraction is optimized using a simulated annealing algorithm. j and distillation volume D j During the optimization process, the batch distillation process simulation module is continuously invoked to minimize the difference between the composition of each fraction and the product requirements (minimizing the objective function), thereby obtaining the appropriate reflux ratio R for each fraction. j and distillation volume D j .

[0041] Add the higher fatty alcohol feedstock to be separated into the feed tank 2, turn on the feed tank heating system, and after the material melts, open the bottom valve to add the material into the distillation kettle 1. After checking the airtightness, turn on the vacuum pump 10. When the vacuum of the distillation system reaches an absolute pressure of about 80-100 Pa, turn on the distillation kettle heating system to heat the material. After reflux appears at the top of the column, perform total reflux operation for 30 minutes. After the total reflux is completed, start collecting the material into the first receiving tank V1 according to the reflux ratio of the first fraction obtained by simulation optimization calculation. When the material volume in the first receiving tank reaches the material volume calculated by simulation, stop discharging into the first receiving tank. According to the reflux ratio of the second fraction calculated by simulation, collect the material into the second receiving tank V2, and so on. 3-10 fractions can be collected from the top of the column. When the last fraction has been collected, open the bottom valve of the distillation kettle 1 to release the residue into the bottom residue tank 12. After the residue is discharged, close the bottom valve of the distillation kettle 1. Add the next batch of material to the feed tank 2 in advance and melt it. Open the bottom valve of feed tank 2 and add the material from the feed tank to distillation vessel 1 to begin the next batch of distillation. During distillation, the top temperature of the column is 170-250℃, and the reflux ratio is 1:1-9:1. The top temperature T during distillation... T Tower top pressure P TThe pressure difference ΔP between the top and bottom of the column is transmitted to the computer in real time. A suitable ΔP is determined based on the packing type and height. The heating rate is adjusted to maintain a stable ΔP, thereby controlling the evaporation rate in the reboiler. A reflux ratio controller automatically controls the reflux ratio. The concentration of each fraction is easily controlled by adjusting the reflux ratio and distillation rate for each fraction. The material level in the receiving tank is displayed via liquid level measurement.

[0042] Compared with the prior art, the positive effects of the present invention are as follows:

[0043] This invention utilizes high-vacuum intermittent distillation technology to separate and purify higher fatty alcohols. It employs single-tower operation, resulting in low equipment investment, flexible operation, and a wide range of applicable raw materials. Through simulation optimization, the main control focuses on the reflux ratio and the distillate output of each fraction to obtain the desired composition, enabling on-demand production. Stable distillation is maintained by controlling the pressure difference between the top and bottom of the column. The production process is simple to control, with a high level of automation and intelligence. The condenser at the top of the distillation column is an evaporative condenser, using water as the evaporation medium for material condensation. Water has a boiling point of 100°C, higher than the melting point of higher fatty alcohols, thus solving the blockage problem caused by the high melting point and easy crystallization of these alcohols. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the batch distillation simulation and optimization process of the present invention.

[0045] Figure 2 This is a schematic diagram of the equipment of the present invention.

[0046] Figure 2 Chinese logo explanation:

[0047] 1-Distillation kettle, 2-Feed tank, 3-Distillation column, 4-Evaporator condenser, 5-Media condenser, 6-Reflux ratio distributor, 7, 8-Collectors, V1, V2...Vn-Receiving tank, 9-Buffer tank, 10-Vacuum pump, 11-Computer, 12-Residue tank.

[0048] Figure 3 This is a flowchart of the process operation of the present invention. Detailed Implementation

[0049] The following provides a detailed description of the embodiments of the present invention. These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments.

[0050] The device used, such as Figure 2As shown, the system includes a distillation kettle, a feed tank, a distillation column, an evaporator-condenser, a medium condenser, a reflux distributor, a collector, a receiving tank, a buffer tank, a vacuum pump, a computer, and a residue tank. The distillation column has a reflux distributor at the top, and an evaporator-condenser above it for condensing the vapors of higher fatty alcohols. The evaporator-condenser is connected to the medium condenser, which cools the medium. The distillation column has a distillation kettle at the bottom, with a feed tank above it for melting the feedstock. The bottom of the distillation kettle is connected to the residue tank for collecting residue. The top of the distillation column is connected to a receiving tank group via the reflux distributor to collect different fractions separated at the top. Two collectors are connected above the evaporator-condenser to collect the material vapors that the evaporator-condenser fails to condense. The collected material flows into a buffer tank connected below the collectors. The top of the buffer tank is connected to the vacuum pump to provide a vacuum for the system. The distillation process is optimized and controlled by a computer through digital simulation.

[0051] This invention provides a digital simulation-optimized process for assisted batch distillation purification of higher fatty alcohols from rice bran wax, such as... Figure 3 As shown, it includes the following steps:

[0052] S1 uses digital simulation to optimize the reflux ratio and distillation rate of each fraction based on the composition of the higher fatty alcohol feedstock, the feed rate, and the separation requirements (see [link]). Figure 1 The calculation involves determining the theoretical number of plates based on the type and height of the packing in the distillation column, determining the appropriate evaporation rate based on the vacuum of the distillation system and the diameter of the distillation column, determining the pressure difference of the column based on the type, height, and evaporation rate, and using a simulated annealing optimization algorithm to obtain the reflux ratio and the distillation rate of each fraction that meet the separation requirements.

[0053] S2 weighs the specified amount of high-grade fatty alcohol raw material and adds it to the chemical tank 2, then turns on the heating system of the chemical tank to melt the raw material.

[0054] S3 activates the vacuum system to evacuate the system, achieving an absolute pressure of 80-100 Pa at the top of the column. Open the bottom valve of feed tank 2 and add the feed liquid to the lower distillation vessel 1. Start the heating system in the distillation vessel to begin heating. The vapor generated by the feed material enters the evaporator-condenser 4 through the distillation column 3. The evaporator-condenser tube space is filled with soft water. The feed vapor flows inside the tubes, transferring heat to the soft water, causing it to vaporize. Simultaneously, the feed vapor condenses and refluxes. After reflux occurs at the top of the column, total reflux is performed for 30 minutes. During the total reflux process, the pressure differential of the column is maintained stable.

[0055] After the total reflux in S4 is completed, the reflux ratio distributor 6 at the top of the column is activated. The first fraction is collected according to the reflux ratio calculated by simulation, and the collected material enters the first receiving tank V1. When the material in the first receiving tank reaches the calculated amount, the first fraction distillation stage ends, and material collection into the first receiving tank stops. Based on the calculated reflux ratio of the second fraction stage, material is discharged into the second receiving tank V2. When the material in the second receiving tank V2 reaches the calculated amount, material discharge into the second receiving tank stops. Then, based on the reflux ratio of the third fraction stage, material is discharged into the third receiving tank V3, and so on, until the last fraction is discharged. The pressure differential of the column is maintained stable throughout the distillation process.

[0056] After the last fraction from the top of column S5 has been collected, close the top reflux distributor 6 and open the bottom discharge valve of distillation vessel 1 to release the residual liquid into the lower residual tank 12. Then, put the next batch of material from the feed tank 2 into distillation vessel 1 for the next batch of distillation.

[0057] Example 1

[0058] A high-vacuum distillation apparatus is used, wherein the diameter of the distillation column is [missing information]. It is filled with CY700 wire mesh packing, with a packing layer height of 900mm. The feed amount is 285g, and the raw material composition is: C18 0.04173%, C19 0.03651%, C20 0.04698%, C21 0.77700%, C22 0.39873%, C23 0.10913%, C24 2.30430%, C25 0.82984%, C26 4.18302%, C27 6.417647%, C28 51.20855%, C29 3.40244%, C30 29.76540%, C31 0.09845%, C32 0.37996%.

[0059] The product requirements are as follows:

[0060] Fraction 1: C24 18% ± 2%, C26 13% ± 2%, C28 37% ± 2%, C30 ≤ 5%, other components have no restrictions.

[0061] Fraction 2: C26 12% ± 2%, C28 60% ± 2%, C30 ≤ 10%, other components have no restrictions.

[0062] Fraction 3: C28 68% ± 2%, C30 ≤ 15%, other components have no restrictions.

[0063] Fraction 4: C28 70% ± 2%, C30 ≤ 15%, other components have no restrictions.

[0064] Fraction 5: C28 68% ± 2%, C30 ≤ 20%, other components have no restrictions.

[0065] Fraction 6: C28 60% ± 2%, C30 ≤ 30%, other components have no restrictions.

[0066] Fraction 7: C28 48% ± 2%, C30 ≥ 40%, other components have no restrictions.

[0067] Fraction 8: C28 ≤ 30%, C30 65% ± 2%, other components have no restrictions.

[0068] Based on the objective function:

[0069]

[0070] In the above objective function:

[0071] OF - Objective Function. The smaller the OF, the closer it is to the product requirements.

[0072] —The concentration of the i-th component in the j-th fraction segment expected to be achieved in the product requirements. The superscript RD (RequestedData) refers to the data required by the product requirements.

[0073] --The concentration of the i-th component in the j-th fraction of the simulation calculation. The superscript CD (Calculated Data) refers to the calculated data.

[0074] C - Total number of components; q - Total number of fractions;

[0075] - The concentration range of component k in the m fraction of the product is limited, where a is the lower limit and b is the upper limit. If only the lower limit exists, then the lower limit is a and b = 1. If only the upper limit exists, then a = 0 and the upper limit is b.

[0076] —The weighting factor of component i in the j-th fraction of the product requirements is 0 if the content of component i is not required in the product or if there is a range requirement, and 1 otherwise.

[0077] For ease of calculation, the component codes are defined as follows: i=1 is C18, i=2 is C19, i=3 is C20, i=4 is C21, i=5 is C22, i=6 is C23, i=7 is C24, i=8 is C25, i=9 is C26, i=10 is C27, i=11 is C28, i=12 is C29, i=13 is C30, i=14 is C31, and i=15 is C32.

[0078] The fraction designations are as follows: j=1 for fraction 1, j=2 for fraction 2, j=3 for fraction 3, j=4 for fraction 4, j=5 for fraction 5, j=6 for fraction 6, j=7 for fraction 7, and j=8 for fraction 8.

[0079] The product requirements are then expressed as:

[0080]

[0081] a = 0

[0082] b=1

[0083] Based on the separation requirements, the objective function of this embodiment is as follows:

[0084]

[0085] a = 0

[0086] b=1

[0087] The column is under a vacuum of 100 Pa (absolute pressure) at the top, with a pressure difference of 100 Pa, a liquid holdup of 1 g / theoretical plate, 6 theoretical plates, and 8 fractions collected.

[0088] Based on the objective function and tower data, the reflux ratio R of each fraction is continuously adjusted during the calculation. j and distillation volume D j This minimizes the objective function OF. The calculation results are as follows:

[0089] Fraction 1 reflux ratio R1 = 5, distillate D1 = 25g.

[0090] Fraction 2 reflux ratio R2 = 6, distillate D2 = 38g.

[0091] Fraction 3 reflux ratio R3 = 4, distillate D3 = 31g.

[0092] Fraction 4, reflux ratio R4 = 9, distillate D4 = 39g.

[0093] Fraction 5 reflux ratio R5 = 4, distillate D5 = 34g.

[0094] Fraction 6 reflux ratio R6 = 4, distillate D6 = 32g.

[0095] Fraction 7 has a reflux ratio of R7 = 4 and a distillate yield of D7 = 29g. Fraction 8 has a reflux ratio of R8 = 4 and a distillate yield of D8 = 19g.

[0096] The composition of each fraction obtained from the batch distillation simulation calculation under the above conditions is shown in Table 1. During the distillation operation, 285g of raw material was added to the feed tank 2, and the feed tank heating system was turned on to melt all the material. The vacuum system was turned on, and the vacuum at the top of the column was maintained at an absolute pressure of 100Pa. All the material in the feed tank 2 was added to the distillation vessel 1 below, and the distillation vessel heating system was turned on. After the material boiled, the material vapor entered the evaporator-condenser 4 through the distillation column 3. In the evaporator-condenser 4, the material vapor was condensed and refluxed. A total reflux operation was performed for 30 minutes.

[0097] After total reflux is complete, the top reflux distributor 6 is opened, and fraction 1 is collected at a reflux ratio of 5:1 and enters the first receiving tank V1. When the material in the first receiving tank reaches 25g, the discharge to the first receiving tank is stopped, and the reflux ratio is changed to 6:1. The collected fraction 2 enters the second receiving tank V2. When the material in the second receiving tank reaches 38g, the discharge to the second receiving tank is stopped, and fraction 3 is collected at a reflux ratio of 4:1 and enters the third receiving tank V3. When the material in the third receiving tank reaches 31g, the discharge to the third receiving tank is stopped, and fraction 4 is collected at a reflux ratio of 9:1 and enters the fourth receiving tank V4. When the material in the fourth receiving tank reaches 39g, the discharge to the fourth receiving tank is stopped. The material is discharged from the receiving tank. The material fraction 5 is collected at a reflux ratio of 4:1 and enters the fifth receiving tank V5. When the material in the fifth receiving tank reaches 34g, the material fraction 6 is collected and enters the sixth receiving tank V6, with the reflux ratio still maintained at 4:1. When the material in the sixth receiving tank reaches 32g, the material fraction 7 is collected and enters the seventh receiving tank V7, with the reflux ratio maintained at 4:1. When the material in the seventh receiving tank reaches 29g, the material fraction 8 is collected and enters the eighth receiving tank V8, with the reflux ratio maintained at 4:1. When the material in the eighth receiving tank reaches 19g, the top collection of the column is stopped, the heating system of the distillation kettle 1 is turned off, and preparations are made for shutdown. When there is no reflux at the top of the column, the bottom valve of the distillation kettle is opened to release the kettle residue into the kettle residue tank 12.

[0098] The pressure difference in the distillation column was controlled at 100-130 Pa during the rectification process. During the rectification process, the top temperatures of the distillation stages were as follows: first stage: 175-237℃; second stage: 237-243℃; third stage: 243-245.6℃; fourth stage: 245.6-247℃; fifth stage: 247-248℃; sixth stage: 248-249.5℃; seventh stage: 249.5-252.5℃; and eighth stage: 252.5-255.5℃. The composition of each fraction and the residue obtained during the rectification process is shown in Table 2. A comparison of Tables 1 and 2 shows that the calculated results agree well with the actual rectification results, indicating that digital simulation optimization can effectively assist in the rectification operation.

[0099] Table 1. Composition of each distillation fraction and composition of the residue in the still (mass percentage) obtained from simulation calculations in Example 1.

[0100]

[0101]

[0102] Note: FR - distillate, RS - residue in still.

[0103] Table 2. Composition of each distillation fraction and residue (mass percentage) obtained by the apparatus in Example 1.

[0104] <![CDATA[C 18 ]]> 0.04173 0.34741 0.08766 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 <![CDATA[C 19 ]]> 0.03651 0.20844 0.12560 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 <![CDATA[C 20 ]]> 0.04698 0.49506 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 <![CDATA[C 21 ]]> 0.7770 8.68518 0.49770 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 <![CDATA[C 22 ]]> 0.39873 3.96478 0.45342 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 <![CDATA[C 23 ]]> 0.10913 0.84957 0.16549 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 <![CDATA[C 24 ]]> 2.3043 19.97591 2.65188 0.63483 0.32103 0.30646 0.05017 0.00000 0.00000 0.00000 <![CDATA[C 25 ]]> 0.82984 2.46247 2.13819 1.45021 0.67383 0.35439 0.14793 0.06328 0.06150 0.03208 <![CDATA[C 26 ]]> 4.18302 14.18798 12.19178 5.55085 2.77458 1.61772 0.45420 0.24597 0.15612 0.10692 <![CDATA[C 27 ]]> 6.41764 7.65583 10.55163 10.08149 8.99083 6.92712 4.49099 2.71665 1.10867 1.49859 <![CDATA[C 28 ]]> 51.2085 35.60923 61.36070 69.50928 70.38701 68.57054 60.13687 47.96784 25.06111 6.54239 <![CDATA[C 29 ]]> 3.40244 1.43872 1.79244 1.74224 2.99994 3.01217 3.80811 4.99603 7.36533 4.53438 <![CDATA[C 30 ]]> 29.7654 4.11937 7.98347 11.03111 13.85274 19.21160 30.91173 43.73664 65.46184 84.15218 <![CDATA[C 31 ]]> 0.09845 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.23463 0.67355 <![CDATA[C 32 ]]> 0.37996 0.00000 0.00000 0.00000 0.00000 0.00000 0.00000 0.27360 0.55079 2.45991

[0105] Note: FR - distillate, RS - residue in still.

[0106] Example 2

[0107] A high-vacuum distillation apparatus is used, wherein the diameter of the distillation column is [missing information]. interior Dixon packing material, with a packing layer height of 400mm. Feed rate: 300g. Raw material composition: C22 0.11582%, C23 0.02313%, C24 0.88909%, C25 0.84868%, C26 5.93089%, C27 8.73107%, C28 76.9135%, C29 0.96607%, C30 5.58177%.

[0108] The product requirements are as follows:

[0109] Fraction 1: C26 24% ± 2%, C28 50% ± 2%, C30 ≤ 1%, other components have no restrictions.

[0110] Fraction 2: C26 10% ± 2%, C28 72% ± 2%, C30 ≤ 1%, other components have no restrictions.

[0111] Fraction 3: C28 90% ± 2%, C30 ≤ 2%, other components have no restrictions.

[0112] Based on the objective function:

[0113]

[0114] In the above objective function:

[0115] OF - Objective Function. The smaller the OF, the closer it is to the product requirements.

[0116] —The concentration of the i-th component in the j-th fraction segment expected to be achieved in the product requirements. The superscript RD (RequestedData) refers to the data required by the product requirements.

[0117] --The concentration of the i-th component in the j-th fraction of the simulation calculation. The superscript CD (Calculated Data) refers to the calculated data.

[0118] C - Total number of components; q - Total number of fractions;

[0119] - The product requirements specify the range of component k in the m fraction. a is the lower limit and b is the upper limit. If only the lower limit exists, then the lower limit is a and b = 1. If only the upper limit exists, then a = 0 and the upper limit is b.

[0120] —The weighting factor of component i in the j-th fraction of the product requirements is 0 if the content of component i is not required in the product or if there is a range requirement, and 1 otherwise.

[0121] For ease of calculation, the component codes are defined as follows: i=1 is C22, i=2 is C23, i=3 is C24, i=4 is C25, i=5 is C26, i=6 is C27, i=7 is C28, i=8 is C29, and i=9 is C30.

[0122] The fraction designations are as follows: j=1 for fraction 1, j=2 for fraction 2, j=3 for fraction 3.

[0123] The product requirements are then expressed as:

[0124]

[0125] a = 0

[0126] Based on the separation requirements, the objective function of this embodiment is as follows:

[0127]

[0128]

[0129] a = 0

[0130] The column top vacuum is 100 Pa (absolute pressure), the pressure difference is 150 Pa, the total number of theoretical plates is 9, the liquid holdup is 1 g / theoretical plate, and 3 fractions are collected.

[0131] Based on the objective function and column data, continuously adjust the reflux ratio R of each fraction. j and distillation volume D j To minimize the objective function OF.

[0132] The calculation results are as follows:

[0133] Fraction 1 reflux ratio R1 = 9, distillate D1 = 42g.

[0134] Fraction 2 reflux ratio R2 = 8, distillate D2 = 54g.

[0135] Fraction 3 reflux ratio R3 = 6, distillate D3 = 157g.

[0136] The composition of each fraction obtained from the batch distillation simulation calculation under the above conditions is shown in Table 3. During the distillation operation, 300g of raw material is added to the feed tank 2, and the feed tank heating system is turned on to melt all the material. The vacuum system is turned on, and the vacuum at the top of the column is maintained at an absolute pressure of 100Pa. All the material in the feed tank 2 is added to the distillation kettle 1 below, and the distillation kettle heating system is turned on. After the material boils, the material vapor enters the evaporator-condenser 4 through the distillation column 3. In the evaporator-condenser 4, the material vapor is condensed and refluxed. A total reflux operation is performed for 30 minutes. After total reflux is complete, open the top reflux distributor 6 to collect material at a reflux ratio of 9:1 into the first receiving tank V1. When the material in the first receiving tank reaches 42g, stop discharging into the first receiving tank, and the reflux ratio becomes 8:1. The collected material enters the second receiving tank V2. When the material in the second receiving tank reaches 54g, stop discharging into the second receiving tank, and collect material at a reflux ratio of 6:1 into the third receiving tank V3. When the material in the third receiving tank reaches 157g, stop top collection, shut off the heating system of distillation kettle 1, and prepare to shut down the column. When there is no more reflux at the top of the column, open the bottom valve of distillation kettle 1 to release the residue into the residue tank 12. During the distillation process, control the column pressure difference at 150-160Pa. The top temperature of the first stage distillation is 215℃-242℃, the second stage is 242℃-244.4℃, and the third stage is 244.4℃-246.5℃. The composition of each fraction obtained during the distillation process and the residue in the still are shown in Table 4. A comparison of Tables 3 and 4 shows that the calculated results agree well with the actual distillation results, indicating that digital simulation optimization can effectively assist the distillation operation.

[0137] Table 3. Composition of each distillation fraction and composition of the residue in the still (mass percentage) obtained from simulation calculations in Example 2.

[0138] <![CDATA[C 22 ]]> 0.11582 0.826463 0.00000 0.00000 0.00000 <![CDATA[C 23 ]]> 0.02313 0.164999 0.00006 0.00000 0.00014 <![CDATA[C 24 ]]> 0.88909 6.226129 0.09012 0.00044 0.00627 <![CDATA[C 25 ]]> 0.84868 3.231167 1.56489 0.21343 0.01881 <![CDATA[C 26 ]]> 5.93089 23.729438 10.60556 1.29891 0.12773 <![CDATA[C 27 ]]> 8.73107 14.707862 14.87432 7.38738 0.82043 <![CDATA[C 28 ]]> 76.91346 50.773895 72.26806 89.25530 64.38250 <![CDATA[C 29 ]]> 0.96607 0.166765 0.28220 0.71585 3.30192 <![CDATA[C 30 ]]> 5.58177 0.173288 0.31479 1.12871 31.34143

[0139] Note: FR - distillate, RS - residue in still.

[0140] Table 4. Composition of each distillation fraction and residue (mass percentage) obtained from the apparatus in Example 2.

[0141] <![CDATA[C 22 ]]> 0.11582 0.80587 0.00000 0.00000 0.00000 <![CDATA[C 23 ]]> 0.02313 0.15839 0.00000 0.00000 0.00000 <![CDATA[C 24 ]]> 0.88909 5.69838 0.64022 0.05075 0.00000 <![CDATA[C 25 ]]> 0.84868 2.88899 1.85132 0.36845 0.00000 <![CDATA[C 26 ]]> 5.93089 25.59439 9.65674 1.21592 0.00000 <![CDATA[C 27 ]]> 8.73107 13.70974 15.72322 6.44412 2.57159 <![CDATA[C 28 ]]> 76.91346 51.14424 72.12846 90.35789 60.07639 <![CDATA[C 29 ]]> 0.96607 0.00000 0.00000 0.54572 4.76041 <![CDATA[C 30 ]]> 5.58177 0.00000 0.00000 1.01715 32.59161

[0142] Note: FR - distillate, RS - residue in still.

[0143] The technical solutions disclosed and proposed in this invention can be implemented by those skilled in the art by appropriately modifying the conditions and routes, etc. Although the methods and preparation techniques of this invention have been described through preferred embodiments, those skilled in the art can obviously modify or recombine the methods and technical routes described herein without departing from the content, spirit, and scope of this invention to achieve the final preparation technique. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included within the spirit, scope, and content of this invention.

Claims

1. A process for separating higher fatty alcohols from rice bran wax using digital simulation and optimization-assisted batch distillation, characterized in that, Includes the following steps: S1 uses digital simulation to optimize the reflux ratio and distillation rate of each fraction based on the composition, feed rate, and separation requirements of the higher fatty alcohol feedstock to be separated. During the calculation, the theoretical number of plates is determined based on the packing type and height of the distillation column, and the appropriate evaporation rate is determined based on the vacuum of the distillation system and the diameter of the distillation column. Through simulation optimization, the operating parameters that meet the separation requirements, such as the reflux ratio and the distillation rate of each fraction, are obtained. S2 Weigh the specified amount of high-grade fatty alcohol raw material and add it to the melting tank. Turn on the heating system of the melting tank to melt the raw material. S3. Start the vacuum system to evacuate the system until the vacuum at the top of the column reaches an absolute pressure of 80-100 Pa. Open the bottom valve of the feed tank and add the raw material liquid to the distillation kettle. Start the heating system of the distillation kettle to begin heating. The vapor generated by the material enters the evaporator-condenser through the distillation column. The space between the tubes of the evaporator-condenser is filled with soft water. The material vapor flows inside the tubes and transfers heat to the soft water, causing it to vaporize. At the same time, the material vapor condenses and flows back. After reflux appears at the top of the column, total reflux is performed. After S4 completes total reflux, the reflux ratio distributor is activated, and the first fraction is collected according to the reflux ratio obtained through simulation optimization. The material collected from the top of the column enters the first receiving tank. When the material in the first receiving tank reaches the total amount calculated in the simulation, the rectification of the first fraction section ends, and material collection into the first receiving tank stops. According to the reflux ratio of the second fraction section obtained through simulation optimization, material is discharged into the second receiving tank. When the material in the second receiving tank reaches the material amount calculated in the simulation, material discharge into the second receiving tank stops. Then, according to the reflux ratio of the third fraction section, material is discharged into the third receiving tank, and so on, until the last fraction is discharged. After the last fraction is collected from the bottom of column S5, close the top reflux distributor and open the bottom discharge valve of the distillation vessel to release the residue into the residue tank; then, put the next batch of material from the feed tank into the distillation vessel for the next batch of distillation. In step S1, digital simulation optimization calculations are performed based on the raw material composition and product requirements to obtain the reflux ratio R of each fraction that meets the product requirements. j and the distillate D of each fraction j Based on the product composition requirements of each fraction, the optimization objective function is determined as follows: in: OF - objective function; —The concentration of the i-th component in the j-th fraction that is expected to be achieved in the product requirements; --The concentration of the i-th component in the j-th fraction segment calculated by simulation; C - Total number of components; q - Total number of fractions; - The product requirements specify the range of component k in fraction m, where a is the lower limit and b is the upper limit. If only the lower limit exists, then the lower limit is a and b=1. If only the upper limit exists, then a=0 and the upper limit is b. —The weighting factor of component i in the j-th fraction of the product requirements is 0 if the content of component i is not required in the product or if there is a range requirement, and 1 otherwise.

2. An apparatus for implementing the digital simulation and optimization-assisted batch distillation process for separating higher fatty alcohols from rice bran wax according to claim 1; characterized in that, The apparatus used includes a distillation kettle, a feed tank, a distillation column, an evaporator-condenser, a medium condenser, a reflux distributor, traps, a receiving tank, a buffer tank, a vacuum pump, a computer, and a residue tank. The distillation column is equipped with a reflux distributor at the top, and an evaporator-condenser is located above the reflux distributor for condensing the vapors of higher fatty alcohols. The evaporator-condenser tubes are connected to the medium condenser, which is used to cool the medium. The distillation column is equipped with a distillation kettle at the bottom, and a feed tank is connected above the distillation kettle for melting the feedstock. The bottom of the distillation kettle is connected to the residue tank for collecting the residue. The top of the distillation column is connected to a receiving tank group via the reflux distributor for collecting different fractions separated at the top of the column. Two traps are connected above the evaporator-condenser to collect the material vapors that the evaporator-condenser fails to condense. The collected material flows into a buffer tank connected below the traps. The top of the buffer tank is connected to the vacuum pump to provide a vacuum for the system. The distillation process is digitally simulated, optimized, and controlled by a computer.

3. The apparatus for separating higher fatty alcohols from rice bran wax using digital simulation and optimization assisted batch distillation according to claim 2; characterized in that, The medium used in the evaporator-condenser is water. The steam from the top of the evaporator-condenser is cooled into liquid water by the medium-cooling condenser and then circulated back to the evaporator-condenser.

4. The process apparatus for separating higher fatty alcohols from rice bran wax using digital simulation and optimized assisted batch distillation according to claim 2, characterized in that, Two collectors are used for switching. After processing 5-10 batches of material, the collector is switched. The material in the collector isolated from the system is melted by the steam generated by the evaporator condenser and discharged from the collector.

5. The process of separating higher fatty alcohols from rice bran wax by digital simulation and optimization according to claim 1 is applied to the purification of higher fatty alcohols from rice bran wax.

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