A continuous production device and method for preparing squalane from squalene

Abstract

The application provides a continuous production device and method for preparing squalane from squalene. The continuous production device comprises a feeding unit, a reaction unit and a separation unit connected in sequence; the reaction unit comprises a liquid-phase hydrogenation reactor provided with a catalyst fixed bed inside, which is used for catalyzing the continuous hydrogenation reaction of squalene raw materials and hydrogen; the liquid-phase hydrogenation reactor adopts gas-liquid countercurrent contact and is provided with a gas-liquid double circulation temperature control system, which is used for circulating and cooling the gas-phase materials and liquid-phase materials participating in the reaction respectively, so as to strictly control the bed temperature distribution; and the device further comprises a three-stage flash evaporation system, which is used for separating and purifying the liquid-phase materials after hydrogenation and recovering the solvent. The application can realize continuous hydrogenation and excellent bed temperature distribution control, and the hydrogen and solvent consumption of the application is low, which can significantly reduce the production operation cost. The application can replace the existing batch kettle reaction process and solve the continuous production problem of squalene for preparing squalane.

Description

Technical Field

[0001] This invention belongs to the fields of bio-based fine chemicals, deep processing of natural products and green biomanufacturing technology, and specifically relates to an industrial production method for preparing squalane by continuously catalytic hydrogenation reaction using naturally sourced squalene as raw material. Background Technology

[0002] Squalane is a high-value-added branched saturated alkane, belonging to the terpene class of saturated hydrocarbons, with the chemical formula C2. 30 H 62 With a molecular weight of 422.81, it is a colorless, odorless, and tasteless transparent oily liquid at room temperature. Its molecule has a highly saturated straight-chain alkane structure with high molecular symmetry and no carbon-carbon unsaturated double bonds, thus exhibiting excellent chemical stability. It is not easily oxidized or rancid during storage and use, has no photosensitivity or irritation to the skin, and is highly similar in structure to the human sebum membrane, demonstrating excellent biocompatibility.

[0003] Squalane is almost insoluble in water and is well miscible with a variety of plant oils, synthetic oils and silicone oils. It has suitable viscosity, excellent spreading and penetrating properties, long-lasting water retention and moisturizing properties, and good lubricity. It also has excellent thermal stability and weather resistance. It is a widely used high-end oily matrix raw material in cosmetics, pharmaceutical preparations, personal care products and other fields.

[0004] Traditional squalane production primarily relies on animal-derived extraction, typically using squalene extracted from deep-sea shark livers as a precursor, followed by catalytic hydrogenation saturation and refining. Early industrial production was highly dependent on shark liver oil resources, resulting in limited raw material availability, high production costs, and damage to the marine ecosystem due to overfishing. Coupled with increasingly prominent ecological and ethical issues, this source has gradually been restricted and replaced.

[0005] With the development of green chemistry and synthetic biotechnology, the preparation of squalane is gradually shifting towards more sustainable processes. Currently, the mainstream preparation methods mainly include plant extraction, chemical synthesis, and bio-fermentation. Plant extraction uses unsaponifiables from vegetable oils such as olive oil and rice bran oil as raw materials to separate squalene, which is then hydrogenated to obtain squalane. Chemical synthesis often uses petrochemical-based raw materials such as isoprene to prepare squalene intermediates through polymerization reactions, followed by further hydrogenation and purification to obtain the final product. Bio-fermentation uses engineered microorganisms to biosynthesize squalene using carbohydrates as substrates, followed by hydrogenation and purification to obtain high-purity squalane. Among these, bio-fermentation is gradually becoming the mainstream development direction in the field of squalane preparation due to its wide availability of raw materials, green and low-carbon production process, high product purity, and stable quality.

[0006] Yichun Dahai Turtle Life Science Co., Ltd. has proposed a hydrogenation method for plant olefins (CN201911054903.7), which includes: using plant squalene as raw material and an organic solvent as carrier, hydrogenation is carried out in two stages; Stage 1: the initial temperature is 120-140℃, the pressure is 1-2MPa, and hydrogenation is carried out smoothly, slowly and gently under the catalysis of a catalyst until the iodine value of the product decreases to 10-30, thus completing Stage 1 hydrogenation; Stage 2: the temperature is raised to 180-200℃, the pressure is 5-10MPa, and hydrogenation is carried out for 1-4 hours to complete the preparation of squalane; wherein, the content of plant squalene in the raw material is ≥70.0%, and the iodine value is ≥200. The process involves two stages: the first stage of hydrogenation saturates most of the double bonds in squalene, reducing double bond translocation; the second stage completely saturates the remaining small amount of double bonds, effectively reducing squalene double bond translocation isomerization, decreasing the formation of squalane isomers, and improving product quality. However, this patent uses a two-stage batch reactor to prepare squalane, failing to address the challenges of continuous production and posing a higher safety risk.

[0007] Shandong Haike Innovation Research Institute Co., Ltd. has proposed a method for preparing cosmetic-grade squalane (CN202511370817.2), comprising the following steps: 1) catalytically hydrogenating squalene raw material to obtain a reactant containing squalane; the squalene content in the squalene raw material is 90-95 wt%; 2) separating the reactant containing squalane to obtain crude squalane; 3) sequentially filtering, liquid-liquid extraction, and molecular distillation of the crude squalane obtained in step 2) to obtain cosmetic-grade squalane. This patented method does not add organic solvents, is environmentally friendly, and yields high-quality squalane products. However, this patent still uses a high-pressure reactor for the reaction, which cannot be carried out continuously, posing a higher safety risk. Furthermore, the reaction is strongly exothermic, and the patent does not disclose how to remove heat to ensure the system does not exceed its temperature limit.

[0008] The aforementioned patented methods all employ batch reactors for hydrogenation reactions, which suffer from discontinuous production, limited single-reactor processing capacity, and poor batch-to-batch product quality stability. Furthermore, the gas-liquid-solid three-phase mass transfer within the reactor is ineffective, resulting in slow reaction rates, low catalyst utilization efficiency, and long reaction cycles. Since hydrogenation reactions are largely exothermic, the limited heat exchange efficiency of batch reactors easily leads to localized overheating, increasing side reactions and decreasing reaction selectivity. Additionally, the reactor requires repeated pressurization, depressurization, and loading / unloading, resulting in long auxiliary operation times, low equipment utilization and production efficiency, and low operational safety and automation levels. Summary of the Invention

[0009] To address the challenge of continuous production of squalene to squalane and replace the existing batch reactor process, this invention provides a continuous production apparatus and method for squalene to squalane, the technical solution of which is as follows: A continuous production apparatus for preparing squalane from squalene includes a feeding unit, a reaction unit, and a separation unit connected in series; the reaction unit includes a liquid-phase hydrogenation reactor 5, which has a fixed catalyst bed inside for catalyzing the hydrogenation reaction between squalene raw material and hydrogen.

[0010] Squalene molecules contain six carbon-carbon double bonds, which are accompanied by a violent exothermic effect during catalytic hydrogenation. If not handled properly, this heat of reaction can cause the bed temperature to rise sharply, leading to side reactions and catalyst deactivation.

[0011] To effectively control the heat of reaction and stabilize the bed temperature distribution, the liquid-phase hydrogenation reactor 5 in this invention adopts gas-liquid countercurrent contact and is equipped with a gas-liquid dual-circulation temperature control system to strictly control the bed temperature distribution, avoid bed overheating or local overheating, and reduce the side reactions and catalyst deactivation caused by this.

[0012] Specifically, the hydrogenation reactor 5 is provided with a liquid phase feed pipe at the top for supplying the liquid phase material to be hydrogenated into the reactor; a discharge pipe is provided at the bottom of the reactor 5 for discharging the hydrogenated liquid phase material; a liquid phase circulation pipe is connected between the discharge pipe and the liquid phase feed pipe, and a circulation pump 6 and a circulation cooler 7 are provided on the liquid phase circulation pipe for cooling part of the hydrogenated liquid phase material and circulating it to the top of the hydrogenation reactor 5.

[0013] Meanwhile, the lower part of the hydrogenation reactor 5 (referring to the position below the bed and above the liquid level of the reactor) is provided with a hydrogen supply pipe for supplying hydrogen to the reactor 5 below the bed; the upper part of the hydrogenation reactor 5 (referring to the position above the bed and below the liquid inlet) is provided with a hydrogen circulation pipe connected to the hydrogen supply pipe, and the hydrogen circulation pipe is provided with a circulating hydrogen compressor 8 and a circulating hydrogen cooler 9.

[0014] By setting up the aforementioned gas-liquid dual-circulation temperature control system, cooled liquid and gaseous materials can be introduced into the upper and lower ends of the fixed bed in the hydrogenation reactor 5 of this invention, respectively. On the one hand, dual-circulation temperature control can effectively increase the amount of heat removal from the reaction, thereby effectively controlling the overall temperature of the bed; on the other hand, gas-liquid countercurrent flow can improve the overall reaction uniformity of the bed. Specifically, in the upper part of the bed, the liquid material has not yet started the hydrogenation reaction, and the squalene concentration in the liquid stream is the highest at this time. If gas-liquid cocurrent flow is adopted, the hydrogen supply here will also be sufficient, which will lead to a more intense reaction in the upper part of the bed compared to the bottom of the bed. This causes a rapid localized temperature rise in the upper part of the bed. However, by adopting the gas-liquid countercurrent scheme of the present invention, the hydrogen supply can be reduced in the upper part of the bed where the squalene concentration is high (after hydrogen travels upward through the bed, the hydrogen concentration gradually decreases due to reaction consumption, resulting in a lower hydrogen partial pressure and lower hydrogen purity compared to the lower part of the bed, thus reducing the supply). This controls the reaction rate in the upper part of the bed. In the lower part of the bed, although the hydrogen supply is sufficient (high hydrogen partial pressure and high hydrogen purity), the squalene concentration in the liquid phase material has also been significantly reduced due to reaction consumption. This makes the overall reaction rate and heat distribution of the catalyst bed more uniform.

[0015] Preferably, the liquid-phase hydrogenation reactor 5 adopts a trickle bed type, the catalyst is packed in a fixed bed, and liquid phase distributors and gas phase distributors are respectively provided on the upper and lower sides of the catalyst bed. The reactor is filled with hydrogen, and squalene and solvent flow through the catalyst bed in droplets. A gas-liquid separation space is provided at the bottom of the liquid-phase hydrogenation reactor 5. The hydrogen concentration in the top of the reactor is controlled by controlling the purge gas flow rate of the hydrogenation reactor (increasing the purge gas discharge will reduce the accumulation of inert components and increase the hydrogen concentration at the top; the reactor pressure is adjusted by the fresh hydrogen flow rate of 103).

[0016] Preferably, the catalyst is a supported nickel catalyst, more preferably a supported catalyst with a high nickel content and higher activity than Raney nickel, and even more preferably a supported nickel catalyst with a nickel content ≥ 50%.

[0017] The upstream of the liquid phase feed pipe is connected to a feeding unit, which includes a mixer 1, a raw material tank 2, a raw material pump 3, and a feed heater 4 connected in series. The liquid phase feed pipe is connected to the outlet of the feed heater 4, and the connection between the liquid phase circulation pipe and the liquid phase feed pipe is located downstream of the feed heater 4. The feed heater 4 is mainly used for preheating the raw materials during the start-up phase.

[0018] The mixer 1 is used to mix raw material squalene 101, fresh solvent 102 and recycled solvent 115.

[0019] A separation unit is connected downstream of the liquid-phase hydrogenation reactor 5. Specifically, the separation unit includes a three-stage flash evaporation system. The first-stage flash tank 10 is connected to the upper side wall and the bottom discharge pipe of the liquid-phase hydrogenation reactor 5, respectively, for receiving the reactor effluent 105 and the hydrogenation reactor purge gas 108. The top of the first-stage flash tank 10 is equipped with a first-stage purge gas pipe with a first-stage purge gas condenser 11 for discharging the condensed hydrogenation purge gas 109. The bottom of the first-stage flash tank 10 is connected to the second-stage flash tank 12 for supplying it with first-stage flash liquid 110. The bottom of the second-stage flash tank 12 is connected to the third-stage flash tank 15 for supplying it with second-stage flash liquid 111. The bottom of the third-stage flash tank 15 is equipped with a squalane pump 18 for discharging the separated squalane 113 product.

[0020] The bottom of the secondary flash tank 12 is provided with a secondary flash heater 13, and the top is provided with a secondary flash solvent tube with a secondary condenser 14 for discharging the secondary flash solvent 112; the bottom of the tertiary flash tank 15 is provided with a tertiary flash heater 16, and the top is provided with a tertiary flash solvent tube with a tertiary condenser 17 for discharging the tertiary flash solvent 114.

[0021] Preferably, the secondary flash heater 13 and the tertiary flash heater 16 are thermosiphon reboilers, falling film evaporators, or rising film evaporators.

[0022] The downstream of both the secondary condenser 14 and the tertiary condenser 17 are connected to the solvent circulation tank 19. The top of the solvent circulation tank 19 is connected to the vacuum pump 21 to provide a vacuum environment for the secondary and tertiary flash tanks. The bottom of the solvent circulation tank 19 is connected to the inlet of the mixer 1 via the circulation pump 20 to transport the circulating solvent 115 obtained from the secondary and tertiary flash tanks to the feeding unit.

[0023] This invention also provides a continuous production method for preparing squalane from squalene based on the above-mentioned apparatus. The method employs continuous fixed-bed liquid-phase hydrogenation and a three-stage flash evaporation solvent recycling technology to prepare the squalane product, specifically including the following steps: (1) The raw material squalene 101, fresh solvent 102 and circulating solvent 115 are mixed by mixer 1 and then enter the raw material tank 2 for buffering. After being pressurized by raw material pump 3, they are sent to feed heater 4 and then mixed with the cooled circulating liquid 107 and enter the liquid phase hydrogenation reactor 5 from the top. Hydrogen enters the lower part of the liquid phase hydrogenation reactor 5 separately.

[0024] (2) A liquid distributor is provided at the top of the liquid phase hydrogenation reactor 5. The gas venting 108 from the hydrogenation reactor is sent to the first-stage flash tank 10 for separation and recovery of the solvent. Through the liquid phase hydrogenation reaction, squalene is basically hydrogenated into squalane.

[0025] (3) The liquid phase product of the liquid phase hydrogenation reactor 5 is divided into two streams: one part of the reactor effluent is sent to the three-stage flash evaporation system as a product, and the other part is circulated as hydrogenation circulating quench liquid to dilute the raw material concentration and reduce the adiabatic temperature rise of the reactor. The hydrogenation circulating liquid 106 is first pressurized by the circulating pump 6, then sent to the circulating cooler 7 to be cooled to the operating temperature, and then mixed with the raw material.

[0026] (4) In the first-stage flash tank 10, low-pressure flash evaporation is used to separate the purge gas (hydrogenation tail gas) and the solvent-containing squalane. The hydrogenation purge gas 109 is sent to the outside after the solvent is recovered in the first-stage flash purge gas condenser 11, and the first-stage flash liquid 110 is sent to the second-stage flash tank 12.

[0027] (5) In the secondary flash tank 12, a secondary flash heater 13 is provided as a reboiler. Most of the solvent is vaporized and then condensed by the secondary condenser 14. The secondary flash solvent 112 obtained by condensation is sent to the solvent circulation tank 19. The solvent concentration at the bottom of the secondary flash tank 12 is controlled by controlling the heating temperature. The concentrated squalane intermediate product (secondary flash liquid 111) is sent to the tertiary flash tank 15.

[0028] (6) In the three-stage flash tank 15, a three-stage flash heater 16 is provided as a reboiler to further vaporize the solvent, and then condense it through a three-stage condenser 17. The condensed three-stage flash solvent 114 is sent to the solvent circulation tank 19. The solvent concentration at the bottom of the three-stage flash tank 15 is controlled to be ≤1wt% by controlling the heating temperature. The squalane 113 after solvent removal is then sent downstream for further purification through the squalane pump 18.

[0029] (7) The circulating solvent 115 collected in the solvent circulation tank 19 is transported to the inlet of the mixer 1 via the solvent circulation pump 20 for solvent recycling.

[0030] Preferably, the operating conditions of the liquid phase hydrogenation reactor 5 are 70–180°C and 1–6 MPaG, and more preferably 100–150°C and 2–4 MPaG. The temperature range mentioned here specifically refers to the temperature range of the catalyst bed.

[0031] Preferably, after the raw material squalene 101, fresh solvent 102 and recycled solvent 115 are mixed, the mass ratio of squalene to solvent is 1:(0.5-20), more preferably 1:(0.5-10).

[0032] Preferably, the liquid phase circulation ratio (the ratio of circulating liquid 106 to the outlet flow rate of raw material pump 3) of the liquid phase hydrogenation reactor 5 is (1-30):1, more preferably (1-10):1.

[0033] Preferably, the fresh hydrogen ratio (molar ratio of fresh hydrogen to squalene) in the liquid-phase hydrogenation reactor 5 is low, preferably (1-1.5):1, more preferably (1-1.2):1. The hydrogen circulation ratio (ratio of total circulating hydrogen flow rate to fresh hydrogen flow rate) is (0.1-30):1, preferably (0.1-15):1.

[0034] The three-stage flash evaporation system employs a step-by-step pressure reduction operation (achieved by installing pressure reducing valves on the flow lines of the first-stage flash liquid 110, the second-stage flash liquid 111, and the second-stage flash solvent 112). The liquid flows by gravity from the previous stage flash tank to the next stage flash tank. Preferably, the operating pressure of the first-stage flash tank is 0.1–1.0 MPaG, the operating pressure of the second-stage flash tank is ≥0 MPaG and less than the operating pressure of the first-stage flash tank, and the operating pressure of the third-stage flash tank is -0.1–0 MPaG.

[0035] The solvent is preferably a low-boiling-point, non-toxic solvent, and more preferably one or more of isopropanol, ethanol, n-hexane, or cyclohexane.

[0036] Compared to existing technologies, this invention has at least the following advantages: It replaces the traditional batch reactor with a fixed-bed liquid-phase hydrogenation reactor, employs a gas-liquid countercurrent process, and is equipped with a gas-liquid dual-circulation temperature control system. These three elements work synergistically to achieve continuous hydrogenation of squalene with uniform and controllable bed temperature; the reaction process is highly continuous and automated, making it safer and more reliable, effectively solving the problems of high cost and batch-to-batch quality variations in batch reactions; and it has low hydrogen consumption, ≤0.4 Nm³. 3 / kg squalane; the three-stage flash evaporation solvent recycling technology is adopted, resulting in low solvent consumption of ≤0.02kg / kg squalane, which reduces operating costs. Attached Figure Description

[0037] Figure 1 Schematic diagram of a continuous production method for squalane from squalene using a gas-liquid countercurrent process. Figure 2 A schematic diagram of a continuous production method for preparing squalane from squalene using a gas-liquid co-flow process.

[0038] The equipment in the diagram is as follows: 1 is a mixer, 2 is a feed tank, 3 is a feed pump, 4 is a feed heater, 5 is a liquid-phase hydrogenation reactor, 6 is a circulation pump, 7 is a circulation cooler, 8 is a circulation hydrogen compressor, 9 is a circulation hydrogen cooler, 10 is a first-stage flash tank, 11 is a first-stage flash gas condenser, 12 is a second-stage flash tank, 13 is a second-stage flash heater, 14 is a second-stage condenser, 15 is a third-stage flash tank, 16 is a third-stage flash heater, 17 is a third-stage condenser, 18 is a squalane pump, 19 is a solvent circulation tank, 20 is a solvent circulation pump, and 21 is a vacuum pump.

[0039] Pipes in the diagram: 101 is squalene, 102 is fresh solvent, 103 is fresh hydrogen, 104 is reactor feed, 105 is reactor discharge, 106 is circulating liquid before cooling, 107 is circulating liquid after cooling, 108 is purge gas from the hydrogenation reactor, 109 is purge gas from hydrogenation, 110 is primary flash liquid, 111 is secondary flash liquid, 112 is secondary flash solvent, 113 is squalane, 114 is tertiary flash solvent, and 115 is circulating solvent.

[0040] Simplified symbols in the diagram: LS stands for low-pressure steam, CWS stands for circulating cooling water, and HOS stands for circulating hot oil. Detailed Implementation Plan Example 1 like Figure 1 As shown, this embodiment provides a continuous production apparatus for preparing squalane from squalene, including a liquid-phase hydrogenation reactor 5, which has a catalyst fixed bed inside, a liquid-phase feed pipe at the top, and a discharge pipe at the bottom; a liquid-phase circulation pipe is connected between the discharge pipe and the liquid-phase feed pipe, and a circulation pump 6 and a circulation cooler 7 are provided on the liquid-phase circulation pipe; a hydrogenation pipe is provided at the bottom of the hydrogenation reactor 5, and a hydrogen circulation pipe connected to the hydrogenation pipe is provided at the top, and a circulating hydrogen compressor 8 and a circulating hydrogen cooler 9 are provided on the hydrogen circulation pipe.

[0041] The liquid phase hydrogenation reactor 5 adopts a trickle bed type, with liquid phase distributors and gas phase distributors respectively provided on the upper and lower sides of the catalyst bed, and a gas-liquid separation space provided at the bottom of the liquid phase hydrogenation reactor 5.

[0042] The catalyst is a supported nickel catalyst with a nickel content of ≥50%.

[0043] It also includes a mixer 1, a raw material tank 2, a raw material pump 3, and a feed heater 4 connected in series. The liquid phase feed pipe is connected to the outlet of the feed heater 4, and the connection point between the liquid phase circulation pipe and the liquid phase feed pipe is located downstream of the feed heater 4. The feed heater 4 is mainly used for preheating the raw materials during the start-up phase.

[0044] It also includes a three-stage flash evaporation system, wherein the first-stage flash tank 10 is connected to the upper side wall and the bottom discharge pipe of the liquid phase hydrogenation reactor 5 respectively; the top of the first-stage flash tank 10 is provided with a first-stage vent pipe with a first-stage vent gas condenser 11; the bottom of the first-stage flash tank 10 is connected to the second-stage flash tank 12; the bottom of the second-stage flash tank 12 is connected to the third-stage flash tank 15; and the bottom of the third-stage flash tank 15 is provided with a squalane pump 18.

[0045] The bottom of the secondary flash tank 12 is provided with a secondary flash heater 13, and the top is provided with a secondary flash solvent tube with a secondary condenser 14; the bottom of the tertiary flash tank 15 is provided with a tertiary flash heater 16, and the top is provided with a tertiary flash solvent tube with a tertiary condenser 17.

[0046] The secondary flash heater 13 and the tertiary flash heater 16 are falling film evaporators.

[0047] The downstream of both the secondary condenser 14 and the tertiary condenser 17 are connected to the solvent circulation tank 19, the top of which is connected to the vacuum pump 2; the bottom of the solvent circulation tank 19 is connected to the inlet of the mixer 1 via the circulation pump 20.

[0048] Example 2 This embodiment provides a continuous production method for preparing squalane based on the apparatus of Example 1. The apparatus on which the method is based has a capacity of 2,000 tons of squalane per year and an annual operating time of 8,000 hours, corresponding to a squalane yield of approximately 0.25 t / h. The raw material squalene is bio-fermented squalene that has undergone concentration, filtration, and adsorption pretreatment, and does not contain catalyst poisons such as sulfur and chlorine. The solvent is cyclohexane.

[0049] (1) The raw material squalene 101, fresh solvent 102 and recycled solvent 115 are mixed by mixer 1 and then enter the raw material tank 2 for buffering. After being pressurized to 2.2 MPaG by raw material pump 3, they are sent to feed heater 4 (only used during the start-up stage). After being heated to the reaction temperature of 100°C, they are mixed with the cooled recycled liquid 107 and then enter the liquid phase hydrogenation reactor 5. Fresh hydrogen 103 enters the liquid phase hydrogenation reactor 5 separately.

[0050] (2) The purge gas 108 from the hydrogenation reactor is sent to the first-stage flash tank 10 for separation and recovery of the solvent. Through liquid-phase hydrogenation reaction, squalene is basically hydrogenated to squalane.

[0051] (3) The liquid phase product of the liquid phase hydrogenation reactor 5 is divided into two streams: one part of the reactor output is sent to the three-stage flash evaporation system as product 105, and the other part is circulated as hydrogenation circulating liquid 106 to dilute the raw material concentration and reduce the adiabatic temperature rise of the reactor. The hydrogenation circulating liquid 106 is first pressurized to 2.2 MPaG by the circulating pump 6, then sent to the circulating cooler 7 to be cooled to 109°C, and then mixed with the raw material.

[0052] (4) In the first-stage flash tank 10, low-pressure flash evaporation is used to separate the purge gas 109 and the solvent-containing squalane. The purge gas 109 is sent to the outside after the solvent is recovered by the first-stage flash purge gas condenser 11, and the first-stage flash liquid 110 is sent to the second-stage flash tank 12.

[0053] (5) In the secondary flash tank 12, a secondary flash heater 13 is provided as a reboiler. Most of the solvent is vaporized and then condensed by the secondary condenser 14. The condensed solvent 112 is sent to the solvent circulation tank 19. The solvent concentration at the bottom of the secondary flash tank 12 is controlled by controlling the heating temperature. The concentrated secondary flash liquid 111 is sent to the tertiary flash tank 15.

[0054] (6) In the three-stage flash tank 15, a three-stage flash heater 16 is provided as a reboiler to further vaporize the solvent, and then condense it through the three-stage condenser 17. The condensed solvent 114 is sent to the solvent circulation tank 19. The solvent concentration at the bottom of the three-stage flash tank 15 is controlled to be ≤1% by controlling the heating temperature. The squalane 113 after solvent removal is sent to the downstream for further purification through the squalane pump 18.

[0055] (7) All collected solvents are sent to solvent circulation tank 19 and then recycled by solvent circulation pump 20.

[0056] The operating conditions for feed tank 2 are 0.2 MPaG and 40℃; the operating pressure of liquid phase hydrogenation reactor 5 is 2.0 MPaG, the feed temperature is 100℃, the reactor adiabatic temperature rise is 20℃, and the reactor outlet temperature is 120℃.

[0057] After mixing raw material squalene 101, fresh solvent 102, and recycled solvent 115, the mass ratio of raw material squalene (99.6 wt%) to solvent is 1:1, resulting in a squalene mass concentration of 49.8 wt%. The circulation ratio of hydrogenation circulating liquid 106 in this reaction system (the ratio of circulating liquid 106 to the outlet flow rate of raw material pump 3) is 5.6:1. At this point, the squalene concentration is diluted to 7.75 wt%.

[0058] The fresh hydrogen ratio (molar ratio of fresh hydrogen to squalene) in the liquid-phase hydrogenation reactor is 1.05:1, and the fresh hydrogen flow rate is 85.13 Nm³. 3 The hydrogen recirculation ratio (total recirculated hydrogen flow rate to fresh hydrogen flow rate) is 11:1, and the actual total hydrogen flow rate entering the reactor (including inert components in the hydrogen stream) is 1021.56 Nm³. 3 The hydrogenation circulating liquid 106 has a flow rate of 2.8 t / h (calculated based on a circulation ratio of 5.6:1, with a feed flow rate of 0.5 t / h), and is cooled from 120°C to 109°C by circulating cooler 7.

[0059] Liquid-phase hydrogenation reactor 5 uses a supported nickel catalyst with a nickel content of 50 wt%, and the catalyst loading is 3 m³. 3 The squalene conversion rate is ≥99.5 wt%, and the squalane selectivity is ≥99%.

[0060] The operating conditions of the first-stage flash tank 10 are 111℃ and 0.2MPaG. The flow rate of the first-stage flash liquid at the bottom of the first-stage flash tank 10 is 505.9 kg / h. The purge gas 109 is cooled to 40℃ by the first-stage flash purge gas condenser 11, and the liquid phase is returned to the first-stage flash tank 10. The flow rate of the cooled purge gas is 4.41 Nm³. 3 / h.

[0061] The operating conditions of the secondary flash tank 12 are 122℃ and 0.02MPaG. The secondary flash heater 13 uses low-pressure steam for heating. After vaporization, the solvent is condensed to 40℃ by the secondary condenser 14. The flow rate of the condensed solvent 112 is 188.8 kg / h. After secondary flash evaporation, the flow rate of the secondary flash liquid is 317.11 kg / h, of which the solvent content is 16.97 wt%.

[0062] The operating conditions of the three-stage flash evaporator 15 are 240℃ and 30kPaA. The three-stage flash heater 16 uses hot oil for heating. After vaporization, the solvent is condensed to 40℃ in the three-stage condenser 17. The flow rate of the condensed solvent 114 is 58.5kg / h. After three-stage flash evaporation, the squalane flow rate is 258.6kg / h, with a solvent content of 0.5wt% and a squalane purity of 97.65wt%. It is then sent downstream for purification to obtain cosmetic-grade products.

[0063] In this embodiment, cyclohexane is used as the hydrogenation solvent. Through this embodiment, the cyclohexane solvent consumption is only 0.01 kg / kg squalane, and the hydrogen consumption is 0.34 Nm³. 3 / kg squalane.

[0064] In this embodiment, the catalyst bed volume is 3m³. 3 The flow rate of the raw material squalene 101 is approximately 0.3 m³ / s. 3 / h, the residence time for liquid-phase hydrogenation is approximately 10h.

[0065] Table 1 is the logistics data table for the example.

[0066] Table 1 Logistics Data Table for Example 1 Example 3 Using cyclohexane as solvent, a nickel catalyst with a nickel content of 50 wt%, a reactor feed temperature of 110 °C, an adiabatic temperature rise of 20 °C, a reactor outlet temperature of 130 °C, and a reaction pressure of 2.0 MPaG, the squalene conversion rate was 99.6% and the squalane selectivity was 98.8%.

[0067] Example 4 Using cyclohexane as solvent, a nickel catalyst with a nickel content of 50 wt%, a reactor feed temperature of 120 °C, an adiabatic temperature rise of 20 °C, a reactor outlet temperature of 140 °C, and a reaction pressure of 2.0 MPaG, the squalene conversion rate was 99.9% and the squalane selectivity was 98.2%.

[0068] Comparative Example 1 See Figure 2 The continuous production apparatus described in Example 1 is modified to a gas-liquid co-current flow, and the hydrogen circulation is eliminated. Specifically, a mixer 1 is added to the liquid phase feed pipe, the outlet of the circulating cooler 7 is connected upstream of the feed heater 4, and the outlet of the feed heater 4 and fresh hydrogen are connected to the inlet of the mixer 1. After the hydrogen and liquid phase material are mixed in the mixer 1, they enter the liquid phase hydrogenation reactor 5.

[0069] Based on the adjusted apparatus, continuous hydrogenation was carried out using the same operating parameters and catalytic system as in Example 2. The reactor inlet temperature was 100°C, the reactor adiabatic temperature rise was 51°C, the reactor outlet temperature was 151°C, the squalene conversion rate was 99.7 wt%, and the squalane selectivity was 95%. The byproduct content in the obtained squalane product was 4.94 wt%.

[0070] Comparative Example 2 Citation: Example 1 of the patent application "A Hydrogenation Method for Plant Olefins (CN201911054903.7)" filed by Yichun Dahai Turtle Life Science Co., Ltd.: Using plant squalene with a purity of 73.0% as raw material (iodine value 270), the raw material is first pretreated. Specifically, in the presence of toluene, activated clay and activated carbon are added for decolorization pretreatment of the 73.0% plant squalene. The added activated clay accounts for 3% of the mass of the plant squalene. The added activated carbon accounts for 3% of the mass of the plant squalene.

[0071] After the raw material pretreatment is completed, hydrogenation is carried out in two stages using toluene as a carrier; Stage 1: Initial temperature 125℃, pressure 1MPa, under the catalytic action of Pd / C catalyst, the amount of catalyst added is 3.0% of the mass of squalene raw material, hydrogenation is carried out steadily, slowly and gently until the iodine value of the product decreases to 28, completing Stage 1 hydrogenation; Stage 2: The temperature is raised to 200℃, pressure 9MPa, under the catalytic action of Pd / C catalyst, hydrogenation is carried out for 3 hours to complete the preparation of squalane.

[0072] The purity of the product was tested, and the final squalane had a purity of 72.8%, which was confirmed by GC. MS compositional analysis revealed that the squalane cyclic isomer content was 0.9%. Furthermore, a reuse test of the Pd / C catalyst used in the reaction process showed that the catalyst could be reused 13 times.

[0073] This comparative example employs a high-risk intermittent batch hydrogenation process. First, the catalyst, squalene raw material, and reaction solvent are sequentially added to the high-pressure hydrogenation reactor. After the closed system is purged and qualified, the temperature and pressure are gradually increased to carry out the first stage of hydrogenation reaction. After the reaction indicators are qualified by sampling and testing, the temperature and pressure are increased again to carry out the second stage of deep hydrogenation reaction. The reaction is terminated when the reaction test meets the standards. Subsequently, subsequent processes such as cooling, slow depressurization, hydrogen venting, and inert gas replacement are carried out according to specifications.

[0074] This intermittent hydrogenation process requires repeated heating and cooling, and frequent alternating pressure. The reaction equipment and pipelines are subjected to periodic and sudden changes in temperature and pressure over a long period of time. This places extremely high demands on the pressure resistance and fatigue aging resistance of the equipment materials, which can easily cause fatigue damage and sealing failure of the reactor body, seals, valves and pipelines. At the same time, the entire process requires frequent switching and control of key process parameters such as temperature, pressure and hydrogen flow rate. There are many points of manual intervention, large range of operating conditions, and very little room for operational error. This can easily lead to abnormal conditions such as material cross-contamination, hydrogen leakage, over-temperature and over-pressure, and localized overheating, which can then induce major safety accidents such as fire, explosion and reactor collapse. The process inherently carries high safety risks and is difficult to control.

[0075] Although the comparative example clearly states that the reaction time of the second stage is only 3 hours, when the reaction time of the first stage is added together, and the time for early feeding, heating and pressurization, segmented operation switching, intermediate sampling and testing, as well as the auxiliary operation time such as later cooling and depressurization, hydrogen emission, and inert gas replacement is taken into account, the total time for a single batch of the entire batch process can reach more than 10 hours, resulting in a long production cycle and low operating efficiency.

[0076] At the same time, the complex processes and frequent switching of operating conditions and operations will cause significant losses of process media such as nitrogen and hydrogen, and will also easily lead to the entrainment and loss of raw materials, catalyst loss and activity decay; the consumption of various raw and auxiliary materials and utilities will increase significantly, and the unit consumption of materials and energy will rise simultaneously, further increasing the overall production and operating costs and resulting in poor process economy.

Claims

1. A continuous production apparatus for preparing squalane from squalene, comprising a feeding unit, a reaction unit, and a separation unit connected in series; characterized in that: The reaction unit includes a liquid-phase hydrogenation reactor (5), which has a fixed catalyst bed inside for catalyzing the continuous hydrogenation reaction of squalene feedstock and hydrogen. The liquid-phase hydrogenation reactor (5) adopts gas-liquid countercurrent contact and is equipped with a gas-liquid dual-circulation temperature control system to circulate and cool the gaseous and liquid phase materials participating in the reaction, so as to strictly control the bed temperature distribution. The top of the liquid-phase hydrogenation reactor (5) is equipped with a liquid-phase feed pipe for supplying the liquid phase material to be hydrogenated into the reactor. The bottom of the liquid-phase hydrogenation reactor (5) is equipped with a discharge pipe for discharging the hydrogenated material. Liquid phase material; a liquid phase circulation pipe is connected between the discharge pipe and the liquid phase feed pipe, and a circulation pump (6) and a circulation cooler (7) are provided on the liquid phase circulation pipe; used to cool part of the hydrogenated liquid phase material and circulate it to the top of the hydrogenation reactor 5; at the same time, a hydrogenation pipe is provided at the bottom of the liquid phase hydrogenation reactor (5) for supplying hydrogen to the liquid phase hydrogenation reactor (5) below the bed layer; a hydrogen circulation pipe is provided at the top of the liquid phase hydrogenation reactor (5) to connect the hydrogenation pipe, and a circulating hydrogen compressor (8) and a circulating hydrogen cooler (9) are provided on the hydrogen circulation pipe.

2. The continuous production apparatus for preparing squalane from squalene as described in claim 1, characterized in that: The upstream of the liquid phase feed pipe is connected to the feed unit, which includes a mixer (1), a raw material tank (2), a raw material pump (3) and a feed heater (4) connected in series. The liquid phase feed pipe is connected to the outlet of the feed heater (4), and the connection position of the liquid phase circulation pipe and the liquid phase feed pipe is located downstream of the feed heater (4). The mixer (1) is used to mix the raw material squalene (101), fresh solvent (102) and circulating solvent (115).

3. The continuous production apparatus for preparing squalane from squalene as described in claim 2, characterized in that: A separation unit is connected downstream of the liquid phase hydrogenation reactor (5). The separation unit includes a three-stage flash evaporation system. The first-stage flash tank (10) is connected to the upper side wall and the bottom discharge pipe of the liquid phase hydrogenation reactor (5) to receive the reactor discharge (105) and the hydrogenation reactor purge gas (108). The top of the first-stage flash tank (10) is provided with a first-stage purge gas pipe with a first-stage purge gas condenser (11). The bottom of the first-stage flash tank (10) is connected to the second-stage flash tank (12). The bottom of the second-stage flash tank (12) is connected to the third-stage flash tank (15). The bottom of the third-stage flash tank (15) is provided with a squalane pump (18).

4. The continuous production apparatus for preparing squalane from squalene as described in claim 3, characterized in that: The bottom of the secondary flash tank (12) is provided with a secondary flash heater (13), and the top is provided with a secondary flash solvent tube with a secondary condenser (14); the bottom of the tertiary flash tank (15) is provided with a tertiary flash heater (16), and the top is provided with a tertiary flash solvent tube with a tertiary condenser (17).

5. The continuous production apparatus for preparing squalane from squalene as described in claim 4, characterized in that: The downstream of both the secondary condenser (14) and the tertiary condenser (17) is connected to a solvent circulation tank (19), the top of which is connected to a vacuum pump (21); the bottom of the solvent circulation tank (19) is connected to the inlet of the mixer (1) via a circulation pump (20).

6. The continuous production apparatus for preparing squalane from squalene according to any one of claims 1-5, characterized in that: The liquid-phase hydrogenation reactor (5) adopts a trickle bed type; the catalyst is a supported nickel catalyst.

7. A continuous production method for preparing squalane from squalene based on the apparatus of claim 5 or 6, characterized in that, Includes the following steps: (1) Raw material squalene (101), fresh solvent (102) and recycled solvent (115) are mixed by mixer (1) and then enter the raw material tank (2) for buffering. After being pressurized by raw material pump (3), they are sent to feed heater (4) and then mixed with the cooled recycled liquid (107) and enter the liquid phase hydrogenation reactor (5) from the top. Hydrogen enters the lower part of the liquid phase hydrogenation reactor (5) separately. (2) The liquid phase hydrogenation reactor (5) is equipped with a liquid distributor at the top. The gas (108) released from the hydrogenation reactor is sent to the first-stage flash tank (10) for separation and recovery of the solvent. Through the liquid phase hydrogenation reaction, squalene is basically hydrogenated into squalane. (3) The liquid phase product of the liquid phase hydrogenation reactor (5) is divided into two streams: one part of the reactor output is sent to the three-stage flash evaporation system as the product, and the other part is circulated as hydrogenation circulating quench liquid to dilute the raw material concentration and reduce the adiabatic temperature rise of the reactor; the hydrogenation circulating liquid (106) is first pressurized by the circulating pump (6), then sent to the circulating cooler (7) to be cooled to the operating temperature, and then mixed with the raw material; (4) In the first-stage flash tank (10), the gas and solvent-containing squalane are separated by low-pressure flash evaporation. The hydrogenated purge gas (109) is sent to the outside after the solvent is recovered by the first-stage flash purge gas condenser (11). The first-stage flash liquid (110) is sent to the second-stage flash tank (12). (5) In the secondary flash tank (12), a secondary flash heater (13) is provided as a reboiler. Most of the solvent is vaporized and then condensed by the secondary condenser (14). The secondary flash solvent (112) obtained by condensation is sent to the solvent circulation tank (19). The solvent concentration at the bottom of the secondary flash tank (12) is controlled by controlling the heating temperature. The concentrated secondary flash liquid (111) is sent to the tertiary flash tank (15). (6) In the three-stage flash tank (15), a three-stage flash heater (16) is provided as a reboiler to further vaporize the solvent, and then condense it through a three-stage condenser (17). The condensed three-stage flash solvent (114) is sent to the solvent circulation tank (19). By controlling the heating temperature, the solvent concentration at the bottom of the three-stage flash tank (15) is controlled to be ≤1wt%. The squalane (113) after solvent removal is then sent to the downstream for further purification through the squalane pump (18). (7) The circulating solvent (115) collected in the solvent circulation tank (19) is transported to the inlet of the mixer (1) via the solvent circulation pump (20) for solvent recycling.

8. The continuous production method for preparing squalane from squalene as described in claim 7, characterized in that: The operating conditions of the liquid phase hydrogenation reactor (5) are 70-180℃ and 1-6MPaG, preferably 100-150℃ and 2-4MPaG.

9. The continuous production method for preparing squalane from squalene as described in claim 7, characterized in that: After the raw material squalene (101), fresh solvent (102) and recycled solvent (115) are mixed, the mass ratio of squalene to solvent is 1:(0.5-20); the liquid phase recycling ratio of the liquid phase hydrogenation reactor (5) is (1-30):1; the fresh hydrogen ratio of the liquid phase hydrogenation reactor (5) is (1-1.5):1; and the hydrogen recycling ratio is (0.1-30):

1.

10. The continuous production method for preparing squalane from squalene as described in claim 7, characterized in that: The three-stage flash system adopts a step-by-step pressure reduction operation. The liquid flows by gravity from the upper flash tank to the lower flash tank. The operating pressure of the first-stage flash tank (10) is 0.1 to 1.0 MPaG, the operating pressure of the second-stage flash tank (12) is ≥0 MPaG and less than the operating pressure of the first-stage flash tank (10), and the operating pressure of the third-stage flash tank (15) is -0.1 to 0 MPaG.

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