Ultralow-viscosity silicone oil nanofiltration low-boiling-point removal device and low-boiling-point removal process
By using nanofiltration membrane separation technology in an ultra-low viscosity silicone oil nanofiltration de-oxidation unit, the problem of difficulty in reducing volatile matter in ultra-low viscosity silicone oil has been solved, achieving high yield and high quality silicone oil production.
Patent Information
- Application Number
- CN202511733188.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-24
- Publication Date
- 2026-01-27
AI Technical Summary
Existing technologies are unable to effectively reduce the volatiles in ultra-low viscosity silicone oils, especially small molecules with molecular weights between 200 and 500 Da, resulting in lower product quality. Furthermore, increasing the de-lowering temperature or time will affect the silicone oil yield.
An ultra-low viscosity silicone oil nanofiltration device is used, which utilizes TiO2, ZrO2, polyamide, sulfonated polysulfone or polyvinyl alcohol organic polymer membranes as nanofiltration membranes, combined with a rotary thin film evaporator and a sieve for separation, with a molecular weight cutoff of 500-2000 Da, to achieve the separation of gaseous low molecular weight silicone oil.
It significantly reduces the low molecular weight content in silicone oil to less than 1.0%, improves the yield and product quality of silicone oil, and meets the market demand for high-quality silicone oil.
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Figure CN121401682A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of ultra-low viscosity silicone oil descaling, specifically to an ultra-low viscosity silicone oil nanofiltration descaling device and descaling process. Background Technology
[0002] Ultra-low viscosity silicone oil typically refers to polysiloxanes with a viscosity of 0.65–20 cSt. During the preparation process, ultra-low viscosity silicone oil polymerizes and contains 30–50% small molecules. After conventional de-degradation using a thin-film evaporator, the volatile matter content of 20 cSt silicone oil can be reduced to less than 5%, while silicone oil below 10 cSt typically has a volatile matter content of 5%–20%, resulting in lower product quality. This is because the molecular weight of ultra-low viscosity silicone oil is below 3000 Da, the average molecular weight of 20 cSt silicone oil is 2600 Da, 10 cSt silicone oil is 1200 Da, and 5 cSt silicone oil is 700 Da. The low molecular weight molecules in silicone oil range from 200 to 500 Da. The small difference between the molecular weight of silicone oil and low molecular weight molecules means that during de-degradation under high temperature and vacuum conditions, silicone oil and low molecular weight molecules are almost simultaneously removed, making it difficult to achieve a significant reduction in volatile matter. Increasing the de-degradation temperature or time can indeed further reduce the volatile matter content, but this results in a significantly lower yield of silicone oil.
[0003] With the expansion of application areas and product upgrades, the market demand for silicone oil quality is increasing, and volatile matter is the most basic and important quality indicator of silicone oil. To solve the current problem of volatile matter in ultra-low viscosity silicone oil (5-20 cSt), a nanofiltration de-volatile matter removal device and process for ultra-low viscosity silicone oil are proposed. Summary of the Invention
[0004] To produce ultra-low viscosity silicone oil with low volatile content, this invention provides an ultra-low viscosity silicone oil nanofiltration de-lowering device and de-lowering process.
[0005] The de-lowering device includes a preheater, a rotary thin-film evaporator, a heavy component tank A, a sieve, a heavy component tank B, a condenser, a light component tank, and a vacuum system.
[0006] The preheater is connected to the feed inlet of a rotary thin-film evaporator. The bottom outlet of the rotary thin-film evaporator is connected to the heavy component tank A. The side vapor outlet of the rotary thin-film evaporator is connected to a sieve. The bottom outlet of the sieve is connected to the heavy component tank B. The side vapor outlet of the sieve is connected to a condenser. The bottom of the condenser is connected to a light component tank. The light component tank is connected to a vacuum system.
[0007] Furthermore, the sieve is equipped with a nanofiltration membrane, the nanofiltration membrane's retention side is connected to the heavy component tank B, and its permeation side is connected to the condenser.
[0008] Furthermore, the nanofiltration membrane in the sieve is made of TiO2 or ZrO2 ceramic membrane, and the membrane has a molecular weight cutoff of 500 to 2000 Da.
[0009] This invention also provides a method for nanofiltration de-lowering of ultra-low viscosity silicone oil using the above-mentioned de-lowering device: (1) Silicon oil preheating and de-lowering: After preheating, the ultra-low viscosity silicone oil is pumped into the rotary thin film evaporator. Under high temperature vacuum film scraping conditions, the unvaporized heavy components of the silicone oil are collected in the heavy component tank A, and the vaporized low molecular weight (the heavy components that have volatilized part of the doped part) enter the sieve with the vacuum.
[0010] (2) Sieving: The gaseous low molecules that enter the sieve move toward the nanofiltration membrane under vacuum. Small molecules in the gaseous low molecules pass through the nanofiltration membrane and enter the condenser for condensation and are collected in the light component tank. Large molecules (heavy components) in the gaseous low molecules are retained and collected in the heavy component tank B.
[0011] In step (1), the viscosity of the silicone oil is 5-20 cSt, the temperature of the silicone oil after preheating is 160-220℃, and the content of low components is 1-50%.
[0012] In step (1), the vacuum degree inside the rotary thin-film evaporator is 10–200 Pa, the material temperature is 160–220 °C, and the material flow rate is 0.7–1.3 m³ / s. 3 / h.
[0013] In some preferred embodiments, the vacuum level inside the rotary thin-film evaporator is 10–100 Pa, the material temperature is 180–220 °C, and the material flow rate is 0.7–1.2 m³ / s. 3 / h.
[0014] In step (2), the vaporized low molecular weight molecules in the sieve have a molecular weight of 200 to 500 Da.
[0015] Using the process described in this invention, the low molecular weight content is less than 1.0%, more preferably less than 0.8%, and even more preferably less than 0.5%.
[0016] Beneficial effects: Therefore, this invention uses a thin-film evaporator for descaling. The descaled gasified material contains approximately 70% low molecular weight (200-500 Da) and approximately 30% silicone oil (≥500 Da). Under negative pressure, the gasified material passes through a nanofiltration membrane with a retention capacity of ≥500 Da in a separator to separate the descaled low molecular weight from some of the ultra-low viscosity silicone oil, thereby ensuring a high yield of ultra-low viscosity silicone oil. Based on this, the descaling temperature can be appropriately increased, or a series of thin-film evaporators or short-molecule distillers can be added to reduce the low molecular weight content in the silicone oil. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the device of the present invention.
[0018] In the diagram: 1. Preheater; 2. Rotary thin-film evaporator; 3. Heavy component tank A; 4. Screener; 5. Heavy component tank B; 6. Condenser; 7. Light component tank; 8. Vacuum system; 9. Nanofiltration membrane. Detailed Implementation
[0019] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.
[0020] Example 1 An ultra-low volatile silicone oil atomization removal device. The removal device includes a preheater 1, a rotary thin-film evaporator 2, a heavy component tank A3, a sieve 4, a heavy component tank B5, a condenser 6, a light component tank 7, and a vacuum system 8. The preheater 1 is connected to the inlet of the rotary thin-film evaporator 2; the bottom outlet of the rotary thin-film evaporator 2 is connected to the heavy component tank A3; the side vapor outlet of the rotary thin-film evaporator 2 is connected to the sieve 4; the bottom outlet of the sieve 4 is connected to the heavy component tank B5; the side vapor outlet of the sieve 4 is connected to the condenser 6; the bottom of the condenser 6 is connected to the light component tank 7; and the light component tank 7 is connected to the vacuum system 8.
[0021] The sieve 4 is equipped with a nanofiltration membrane 9. The nanofiltration membrane 9 is connected to the heavy component tank B5 on the retention side and to the condenser 6 on the permeation side.
[0022] The nanofiltration membrane in the sieve is made of TiO2 ceramic membrane, and the membrane has a molecular weight cutoff of ≥500 Da.
[0023] Example 2 A nanofiltration process for removing low viscosity silicone oil, using the apparatus of Example 1, involves preheating 10cSt grade silicone oil with a volatile content of 40.03% to 200°C in preheater 1, followed by nanofiltration at 1m... 3 The silicone oil enters the rotary thin-film evaporator 2 at a flow rate of / h. The absolute pressure inside the thin-film evaporator is 100Pa, and the temperature of the silicone oil is 200℃. After the film is scraped, the volatile components in the silicone oil escape and enter the sieve. The vaporized low molecular weight molecules in the sieve are 200-500Da. Among them, small molecules with a molecular weight below 500Da pass through the TiO2 ceramic membrane with a molecular weight cutoff of ≥500Da in the sieve and enter the condenser for condensation and collection in the light component tank. The large molecular weight silicone oil with a molecular weight above 500Da is cut off by the nanofiltration membrane in the sieve and collected in the heavy component tank B. The silicone oil that has not volatilized in the thin-film evaporator is collected in the heavy component tank A. Finally, the materials in the heavy component tanks A and B are mixed to obtain the finished product.
[0024] Low molecular weight content: The molecular weight of silicone oil below 500 Da was determined by gas chromatography (GC).
[0025] Yield: Yield = Total amount of silicone oil in recombinant tank A and recombinant tank B / Total amount of silicone oil before desaturation.
[0026] Example 3 The operation steps are the same as in Example 2, except that the TiO2 ceramic film with a value of ≥500 Da in Example 2 is changed to a ZrO2 ceramic film with a value of ≥500 Da.
[0027] Example 4 The operation steps are the same as in Example 2, except that the TiO2 ceramic film with a capacity of ≥500 Da in Example 2 is changed to a polyamide organic polymer film with a capacity of ≥500 Da.
[0028] Example 5 The operating steps are the same as in Example 2, except that the TiO2 ceramic film with a capacity of ≥500 Da in Example 2 is changed to a sulfonated polysulfone organic polymer film with a capacity of ≥500 Da.
[0029] Example 6 The operation steps are the same as in Example 2, except that the TiO2 ceramic film with a capacity of ≥500 Da in Example 2 is changed to a polyvinyl alcohol organic polymer film with a capacity of ≥500 Da.
[0030] Table 1 shows the applicability of nanofiltration membranes of various materials in high-temperature environments in Examples 2, 3, 4, 5, and 6.
[0031] Table 1. Applicability of nanofiltration membrane materials in high-temperature environments
[0032] Example 7 The operation steps are the same as in Example 2, except that the TiO2 ceramic film with a value of ≥500 Da in Example 1 is adjusted to a TiO2 ceramic film with a value of ≥1000 Da.
[0033] Example 8 The operation steps are the same as in Example 2, except that the TiO2 ceramic film with a value of ≥500 Da in Example 1 is adjusted to a TiO2 ceramic film with a value of ≥1500 Da.
[0034] Example 9 The operation steps are the same as in Example 2, except that the TiO2 ceramic film with a value of ≥500 Da in Example 1 is adjusted to a TiO2 ceramic film with a value of ≥2000 Da.
[0035] The molecular content below 500 Da and the silicone oil yield results for Examples 2, 7, 8, and 9 are shown in Table 2.
[0036] Table 2. Effect of molecular weight cutoff on low molecular weight content and yield of 10cSt grade silicone oil
[0037] Example 10 The operating steps are the same as in Example 2, except that the 10cSt grade silicone oil with 40.03% volatile matter in Example 2 is replaced with 5cSt grade silicone oil with 43.81% volatile matter for de-lowering.
[0038] Example 11 The operation steps are the same as in Example 10, except that the TiO2 ceramic film with a value of ≥500 Da in Example 2 is adjusted to a TiO2 ceramic film with a value of ≥1000 Da.
[0039] Example 12 The operation steps are the same as in Example 10, except that the TiO2 ceramic film with a value of ≥500 Da in Example 2 is adjusted to a TiO2 ceramic film with a value of ≥1500 Da.
[0040] Example 13 The operation steps are the same as in Example 10, except that the TiO2 ceramic film with a value of ≥500 Da in Example 2 is adjusted to a TiO2 ceramic film with a value of ≥2000 Da.
[0041] The molecular content below 500 Da and the silicone oil yield results for Examples 10, 11, 12 and 13 are shown in Table 3.
[0042] Table 3. Effect of molecular weight cutoff on low molecular weight content and yield of 5cSt silicone oil
[0043] Example 14 The operating steps are the same as in Example 2, except that the 10cSt grade silicone oil with 40.03% volatile matter in Example 2 is replaced with 0.65cSt grade silicone oil with 53.58% volatile matter for de-lowering.
[0044] Example 15 The operation steps are the same as in Example 14, except that the TiO2 ceramic film with a value of ≥500 Da in Example 2 is adjusted to a TiO2 ceramic film with a value of ≥1000 Da.
[0045] Example 16 The operation steps are the same as in Example 14, except that the TiO2 ceramic film with a value of ≥500 Da in Example 2 is adjusted to a TiO2 ceramic film with a value of ≥1500 Da.
[0046] Example 17 The operation steps are the same as in Example 14, except that the TiO2 ceramic film with a value of ≥500 Da in Example 2 is adjusted to a TiO2 ceramic film with a value of ≥2000 Da.
[0047] The molecular content below 500 Da and the silicone oil yield results for Examples 14, 15, 16, and 17 are shown in Table 4.
[0048] Table 4. Effects of molecular weight cutoff on the low molecular weight content and yield of 0.65cSt silicone oil.
[0049] Example 18 The operating steps are the same as in Example 2, except that the 10cSt grade silicone oil with 40.03% volatile matter in Example 2 is replaced with 20cSt grade silicone oil with 27.69% volatile matter for de-lowering.
[0050] Example 19 The operation steps are the same as in Example 18, except that the TiO2 ceramic film with a value of ≥500 Da in Example 2 is adjusted to a TiO2 ceramic film with a value of ≥1000 Da.
[0051] Example 20 The operation steps are the same as in Example 18, except that the TiO2 ceramic film with a value of ≥500 Da in Example 2 is adjusted to a TiO2 ceramic film with a value of ≥2000 Da.
[0052] Example 21 The operation steps are the same as in Example 18, except that the TiO2 ceramic film with a value of ≥500 Da in Example 2 is adjusted to a TiO2 ceramic film with a value of ≥3000 Da.
[0053] The results of the molecular content below 500 Da in silicone oil and the yield of silicone oil in Examples 18, 19, 20 and Example 21 are shown in Table 5.
[0054] Table 5. Effect of molecular weight cutoff on low molecular weight content and yield of 20cSt grade silicone oil
[0055] Example 22 The operating steps are the same as in Example 2, except that the initial volatile content of silicone oil in Example 2 is 31.24%.
[0056] Example 23 The operating steps are the same as in Example 2, except that the initial volatile content of silicone oil in Example 2 is 35.07%.
[0057] Example 24 The operating steps are the same as in Example 2, except that the initial volatile content of silicone oil in Example 2 is 44.68%.
[0058] Example 25 The operating steps are the same as in Example 2, except that the initial volatile content of silicone oil in Example 2 is 49.42%.
[0059] The results of the molecular content below 500 Da and the yield of silicone oil in Examples 2, 22-25 are shown in Table 6.
[0060] Table 6. Effects of initial volatile matter content of silicone oil on low molecular weight content and yield after treatment.
[0061] Example 26 The operating steps are the same as in Example 2, except that the temperature of the silicone oil in the thin-film evaporator in Example 2 is adjusted to 140°C.
[0062] Example 27 The operating steps are the same as in Example 2, except that the temperature of the silicone oil in the thin-film evaporator in Example 2 is adjusted to 160°C.
[0063] Example 28 The operating steps are the same as in Example 2, except that the temperature of the silicone oil in the thin-film evaporator in Example 2 is adjusted to 180°C.
[0064] Example 29 The operating steps are the same as in Example 2, except that the temperature of the silicone oil in the thin-film evaporator in Example 2 is adjusted to 220°C.
[0065] The molecular content below 500 Da and the silicone oil yield results for Examples 2, 27-29 and Example 26 are shown in Table 7.
[0066] Table 7. Effect of temperature during silicone oil desliming on low molecular weight content and yield.
[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A nanofiltration descaling device for ultra-low viscosity silicone oil, comprising a preheater (1), a rotary thin-film evaporator (2), a heavy component tank A (3), a sieve (4), a heavy component tank B (5), a condenser (6), a light component tank (7), and a vacuum system (8); characterized in that, The preheater (1) is connected to the feed inlet of the rotary thin film evaporator (2). The bottom outlet of the rotary thin film evaporator (2) is connected to the heavy component tank A (3). The side gas phase outlet of the rotary thin film evaporator (2) is connected to the sieve (4). The bottom outlet of the sieve (4) is connected to the heavy component tank B (5). The side gas phase outlet of the sieve (4) is connected to the condenser (6). The bottom of the condenser (6) is connected to the light component tank (7). The light component tank (7) is connected to the vacuum system (8).
2. The nanofiltration descaling device for ultra-low viscosity silicone oil according to claim 1, characterized in that, The sieve (4) is equipped with a nanofiltration membrane (9). The nanofiltration membrane (9) is connected to the recombinant tank B (5) on the retention side and to the condenser (6) on the permeation side.
3. The ultra-low viscosity silicone oil nanofiltration desliming device according to claim 1, characterized in that, The nanofiltration membrane (9) in the sieve (4) is made of TiO2 or ZrO2 ceramic membrane, and the membrane has a molecular weight cutoff of 500 to 2000 Da.
4. A nanofiltration process for removing ultra-low viscosity silicone oil, characterized in that, The ultra-low viscosity silicone oil nanofiltration degradation device according to any one of claims 1-3 includes the following steps: (1) Silicone oil preheating and de-lowering: After preheating, the ultra-low viscosity silicone oil is pumped into the rotary thin film evaporator. Under high temperature vacuum film scraping conditions, the unvaporized heavy components of the silicone oil are collected in the heavy component tank A, and the vaporized low molecules enter the sieve with the vacuum. (2) Sieving: The gaseous low molecules that enter the sieve move toward the nanofiltration membrane under vacuum. Small molecules in the gaseous low molecules pass through the nanofiltration membrane and enter the condenser for condensation and are collected in the light component tank. Large molecules in the gaseous low molecules are retained and collected in the heavy component tank B.
5. The nanofiltration de-lowering process for ultra-low viscosity silicone oil according to claim 4, characterized in that, In step (1), the ultra-low viscosity silicone oil has a viscosity of 5-20 cSt, the temperature of the silicone oil after preheating is 160-220℃, and the content of low components is 1-50%.
6. The nanofiltration de-lowering process for ultra-low viscosity silicone oil according to claim 4, characterized in that, In step (1), the vacuum degree inside the rotary thin-film evaporator is 10–200 Pa, the material temperature is 160–220 °C, and the material flow rate is 0.7–1.3 m³ / s. 3 / h.
7. The nanofiltration de-lowering process for ultra-low viscosity silicone oil according to claim 6, characterized in that, In step (1), the vacuum degree inside the rotary thin film evaporator is 10-100 Pa, the material temperature is 180-220℃, and the material flow rate is 0.7-1.2 m³ / h.
8. The nanofiltration de-lowering process for ultra-low viscosity silicone oil according to claim 4, characterized in that, In step (2), the molecular weight of the gaseous low molecular weight molecules in the sieve is 200-500 Da.
9. The nanofiltration de-lowering process for ultra-low viscosity silicone oil according to claim 4, characterized in that, The nanofiltration membrane (9) is made of TiO2 or ZrO2 ceramic membrane, and the membrane has a molecular weight cutoff of 500 to 2000 Da.
10. The process according to any one of claims 4-9, characterized in that, The low molecular weight content is less than 1.0%, more preferably less than 0.8%, and even more preferably less than 0.5%.