CN109593591B

CN109593591B - Low-viscosity poly-alpha-olefin lubricating oil base oil and preparation method and system thereof

Info

Publication number: CN109593591B
Application number: CN201710938311.6A
Authority: CN
Inventors: 丁晖殿; 施昌智; 黄作鑫; 苏朔; 段庆华; 徐冰; 成欣; 么佳耀; 辛世豪; 赵敏
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2017-09-30
Filing date: 2017-09-30
Publication date: 2022-05-17
Anticipated expiration: 2037-09-30
Also published as: CN109593591A

Abstract

The present disclosure relates to a low viscosity polyalphaolefin lubricant base oil, a method and a system for preparing the same, the method comprising the steps of: (1) reacting a feed containing an alpha-olefin with a feed containing BF₃The catalyst and the reaction assistant are subjected to a polymerization reaction in a polymerization reaction device to obtain a product containing BF₃A mixed product of a catalyst, a reaction aid and a polyalphaolefin; (2) the mixed product is sent into a gas-liquid separation device to be heated for gas-liquid separation, and BF is mainly contained₃A gas phase product of the catalyst and a liquid phase product comprising predominantly polyalphaolefin; and (3) returning at least a portion of the gas phase product to the polymerization reaction unit. The disclosed process enables the production of polyalphaolefins having acceptable F content and the continuous separation of BF from polyalphaolefin products₃The catalyst does not need manual intermittent material pouring, does not generate F-containing wastewater in the production process, and can recycle BF₃The catalyst reduces the catalyst waste.

Description

Low-viscosity poly-alpha-olefin lubricating oil base oil and preparation method and system thereof

Technical Field

The disclosure relates to the field of preparation of lubricant base oil, and in particular relates to low-viscosity poly-alpha-olefin lubricant base oil and a preparation method and system thereof.

Background

Lubricating oil specifications are becoming increasingly stringent, and the demand for high quality lubricating and synthetic oils is increasing dramatically, with polyalphaolefins being one of the fastest growing varieties. The lubricating oil has the advantages of wide operating temperature range, good stability at low temperature and high temperature, low pour point, low volatility, good viscosity-temperature performance, high oxidation resistance, high viscosity index and the like, and can be applied to preparing various high-grade engine oils, such as gasoline engine oil, diesel engine oil, compressor oil, military lubricating oil and the like.

The poly-alpha-olefin is mainly long-chain alkane obtained by carrying out polymerization reaction on C8-C12 alpha-olefin under the action of a catalyst and carrying out a series of processes such as separation, hydrogenation and the like. The polyalphaolefins are used in maximum amounts with viscosities of 4cSt and 6cSt at 100 ℃ under the designations PAO-4 and PAO-6. The straight chain alkane skeleton of poly alpha-olefin can ensure good viscosity-temperature characteristic, and its short, more side chains can maintain low-temperature fluidity, and in addition, it contains no aromatic hydrocarbon, cycloparaffin and other groups, and is favorable for physical and chemical stability. Therefore, polyalphaolefins are desirable lubricant base oils.

Catalyst for low viscosity polyalphaolefin lubricants and BF₃Mainly, in the traditional production process, after the reaction is finished, the processes of material pouring, replacement, alkali washing, water washing and the like are required to be carried out to completely remove F ions (below 1 ppm), a large amount of F ion-containing wastewater is generated in the process, and a large amount of BF is consumed₃A catalyst. Therefore, a matched wastewater treatment plant containing F ions needs to be newly built, so that the environmental protection pressure is increased; the catalyst can not be recovered after alkaline washing and water washing, so that the operation cost is increased; if the alkali washing tank and the water washing tank are operated intermittently, the labor cost is increased, and the production hidden trouble is caused.

Disclosure of Invention

It is an object of the present disclosure to provide a method and system for preparing a low viscosity polyalphaolefin lubricant base oil, which can reduce contamination generated in the preparation of the polyalphaolefin lubricant base oil and improve production efficiency.

It is another object of the present disclosure to provide a low viscosity polyalphaolefin lubricant base stock prepared by the above method.

In order to achieve the above object, a first aspect of the present disclosure provides a method for preparing a low viscosity polyalphaolefin lubricant base oil, comprising the steps of: (1) reacting a feed containing an alpha-olefin with a feed containing BF₃The catalyst and the reaction auxiliary agent are subjected to polymerization reaction in a polymerization reaction device to obtain the product containing BF₃A mixed product of a catalyst, a reaction aid and a polyalphaolefin; (2) the mixed product is sent into a gas-liquid separation device to be heated for gas-liquid separation, and BF is mainly contained₃A gas phase product of the catalyst and a liquid phase product comprising predominantly polyalphaolefin; and (3) returning at least a portion of the gas phase product to the polymerization reaction unit.

Optionally, the gas-liquid separation device comprises at least one of a gas-liquid separation column, a gas-liquid separation tank, and a heat exchanger.

Optionally, the gas-liquid separation tower is one of a pressurized separation tower, an atmospheric separation tower and a reduced pressure separation tower, and the number of the tower plates of the gas-liquid separation tower is 1-100.

Optionally, the temperature of the tower kettle of the gas-liquid separation tower is 50-400 ℃.

Optionally, the alpha-olefin feedstock is a C6 to C14 alpha-olefin.

Optionally, the reaction auxiliary agent is at least one of alcohol with 1-20 carbon atoms, ether with 1-20 carbon atoms, carboxylic acid with 1-20 carbon atoms, ester with 1-20 carbon atoms and phenol with 1-20 carbon atoms.

Alternatively, the conditions of the polymerization reaction include: the reaction temperature is-50 to 100 ℃; the reaction pressure is 10Pa to 5 MPa; said alpha-olefin feedstock, said BF₃The molar ratio of the catalyst to the reaction auxiliary agent is 1: (0.001-0.2): (0.001-0.4).

Optionally, the method further comprises: measuring the content of the F element in the liquid-phase product on line; when the content of the F element is higher than a defined standard, returning at least one part of the liquid-phase product to the gas-liquid separation device for gas-liquid separation, and adjusting the separation temperature of the gas-liquid separation device when necessary; when the content of F element does not exceed the defined standard, the liquid phase product is directly subjected to the hydrotreatment.

Optionally, the defined criterion is that the content of element F is not more than 100 ppm.

Optionally, the method further comprises: carrying out heat exchange cooling on the gas-phase product and the mixed product in a first heat exchanger to obtain a first heat exchange product containing a gas phase and a liquid phase; returning at least a portion of the gas phase in the first heat exchanged product to the polymerization reaction unit and optionally discharging another portion of the gas phase in the first heat exchanged product as a tail gas; and refluxing the liquid phase in the first heat exchange product to the gas-liquid separation device through a reflux device at a mass reflux ratio of 0.1-50.

Optionally, the method further comprises: further cooling said first heat exchanged product to obtain a cooled product comprising a gas phase and a liquid phase; returning at least a portion of the gas phase in the cooled product to the polymerization reaction unit and optionally discharging another portion of the gas phase in the cooled product as a tail gas; and refluxing the liquid phase in the cooling product to the gas-liquid separation device through a reflux device at a mass reflux ratio of 0.1-50.

Optionally, the method further comprises: a portion of the liquid phase in the reflux unit is discharged from the reflux unit.

Optionally, the method further comprises: and heating at least one part of the liquid phase product, and then, introducing the heated liquid phase product into a hydrogenation system for hydrogenation treatment to obtain a hydrogenation product with reduced olefin content and serving as the initial product of the lubricating oil base oil.

Optionally, the method further comprises: and (3) carrying out heat exchange treatment on the hydrogenation product and the liquid-phase product in a second heat exchanger.

A second aspect of the present disclosure provides a low viscosity polyalphaolefin lubricant base stock prepared by the process of the first aspect of the disclosure.

A third aspect of the present disclosure provides a system for preparing a low-viscosity polyalphaolefin lubricant base oil, the system comprising a feed inlet, a polymerization reaction device, a gas-liquid separation device and a discharge outlet; the feed inlet is communicated with a reactant inlet of the polymerization reaction device, a product outlet of the polymerization reaction device is communicated with an inlet of the gas-liquid separation device, a liquid outlet of the gas-liquid separation device is communicated with the discharge outlet, and a gas outlet of the gas-liquid separation device is communicated with the reactant inlet of the polymerization reaction device.

Optionally, the system further comprises an online detection device for detecting the impurity elements in the heat exchange medium.

Optionally, the system further comprises a first heat exchanger and a reflux device; the first inlet of the first heat exchanger is communicated with the gas outlet of the gas-liquid separation device, the second inlet of the first heat exchanger is communicated with the product outlet of the polymerization reaction device, the first outlet of the first heat exchanger is communicated with the inlet of the reflux device, the second outlet of the first heat exchanger is communicated with the inlet of the gas-liquid separation device, the liquid outlet of the reflux device is communicated with the inlet of the gas-liquid separation device and is optionally evacuated, and the gas outlet of the reflux device is communicated with the reactant inlet of the polymerization reaction device and is optionally evacuated.

Optionally, the system further comprises a cooling device, the first outlet of the first heat exchanger is communicated with the inlet of the cooling device, and the outlet of the cooling device is communicated with the inlet of the reflux device.

Optionally, the system further comprises a hydrogenation device, an inlet of the hydrogenation device is communicated with a liquid outlet of the gas-liquid separation device, and an outlet of the hydrogenation device is communicated with the discharge hole.

Optionally, the system further comprises a second heat exchanger, a first inlet of the second heat exchanger is communicated with an outlet of the hydrogenation device, a second inlet of the second heat exchanger is communicated with a liquid outlet of the gas-liquid separation device, a first outlet of the second heat exchanger is communicated with the discharge hole, and a second outlet of the second heat exchanger is communicated with the inlet of the hydrogenation device and optionally communicated with an inlet of the gas-liquid separation device.

By the technical scheme, the method for preparing the low-viscosity poly-alpha-olefin lubricating oil base oil disclosed by the invention heats the reaction auxiliary agent and BF in the gas-liquid separation device₃The formed complex is depolymerized, the polyalpha-olefin with qualified F content can be prepared, and BF in the polyalpha-olefin product can be continuously separated₃The catalyst does not need to be poured manually and intermittently, so that the potential safety hazard of production is greatly reduced; the process and system enable polyalphaolefin products to be reacted with BF₃The catalyst is thoroughly separated, no F-containing wastewater is generated in the production process, and BF can be recycled₃The catalyst reduces the catalyst waste. The poly-alpha-olefin lubricating oil base oil prepared by the method has low viscosity and low F element content.

Additional features and advantages of the disclosure will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure without limiting the disclosure. In the drawings:

FIG. 1 is a process flow diagram of one embodiment of the process of making a low viscosity polyalphaolefin lubricant base stock of the present disclosure.

Description of the reference numerals

1 contains BF₃Catalyst 2 containing a-olefin feedstock

3 reaction auxiliary agent 4 polymerization reaction device

5 gas-liquid separation tower 6 first heat exchanger

7 cooler 8 reflux tank

9 heating furnace 10 hydrogenation system

11 compressor 12 second heat exchanger

Detailed Description

The following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.

The present disclosure provides a method for preparing a low viscosity polyalphaolefin lubricant base stock, comprising the steps of: (1) reacting a feed containing an alpha-olefin with a feed containing BF₃The catalyst and the reaction auxiliary agent are subjected to polymerization reaction in a polymerization reaction device to obtain the product containing BF₃A mixed product of a catalyst, a reaction aid and a polyalphaolefin; (2) the mixed product is sent into a gas-liquid separation device to be heated for gas-liquid separation until the mixed product mainly contains BF₃A gas phase product of the catalyst and a liquid phase product comprising predominantly polyalphaolefin; and (3) returning at least a portion of the gas phase product to the polymerization reaction unit.

The disclosed method for preparing a low-viscosity polyalphaolefin lubricant base oil enables a reaction auxiliary and BF to be heated in a gas-liquid separation device₃The formed complex is depolymerized, the polyalpha-olefin with qualified F content can be prepared, and BF in the polyalpha-olefin product can be continuously separated₃The catalyst does not need to be poured manually and intermittently, so that the potential safety hazard of production is greatly reduced; the process enables the production of polyalphaolefin products with BF₃The catalyst is thoroughly separated, no F-containing wastewater is generated in the production process, and BF can be recycled₃The catalyst reduces the catalyst waste.

According to the present disclosure, the gas-liquid separating device may include at least one of a gas-liquid separating tower, a gas-liquid separating tank, and a heat exchanger, preferably the gas-liquid separating tower, so as to control separation operation conditions and improve separation efficiency.

According to the present disclosure, the gas-liquid separation column may be a separation column of a type conventional in the art, the operating conditions of the gas-liquid separation column may be varied within a wide range, and in order to secure the gas-liquid separation efficiency, preferably, the gas-liquid separation column may be one of a pressurized separation column, an atmospheric separation column and a reduced-pressure separation column, preferably, a reduced-pressure separation column; the number of the tower plates of the gas-liquid separation tower can be 1-100, preferably 5-80; the temperature of the tower kettle of the gas-liquid separation tower can be 50-400 ℃, and preferably 100-300 ℃.

In accordance with the present disclosure, the reaction raw material and the catalyst for performing the polymerization of α -olefin may be a conventional kind in the art, and the α -olefin raw material may be an α -olefin having 6 to 14 carbon atoms, for example, at least one selected from the group consisting of 1-decene, 1-octene and 1-dodecene; the reaction auxiliary agent can be at least one of alcohol with 1-20 carbon atoms, ether with 1-20 carbon atoms, carboxylic acid with 1-20 carbon atoms, ester with 1-20 carbon atoms and phenol with 1-20 carbon atoms, and preferably alcohol with 2-8 carbon atoms; containing BF₃In a catalyst of₃The molar content of (a) may be from 10% to 100%, and the catalyst may also contain small amounts of inert components.

In accordance with the present disclosure, the conditions under which the alpha-olefin feedstock is polymerized may be conventional in the art, and to further increase the reaction conversion, the polymerization conditions may include: the reaction temperature is-50 ℃ to 100 ℃, and preferably 0 ℃ to 80 ℃; the reaction pressure is 10-5 MPa, preferably 0.1-2 MPa; alpha-olefin feedstock, BF₃The molar ratio of catalyst to reaction promoter may be 1: (0.001-0.2): (0.001 to 0.4), preferably 1: (0.005-0.1): (0.005-0.2).

According to the present disclosure, in order to further improve the gas-liquid separation efficiency and fully utilize the heat in the reaction system, the method may further include: carrying out heat exchange and cooling on the gas-phase product and the mixed product in a first heat exchanger to obtain a first heat exchange product containing a gas phase and a liquid phase; returning at least a portion of the gas phase in the first heat exchanged product to the polymerization reaction unit, optionally allowing another portion of the gas phase in the first heat exchanged product to be vented as a tail gas in order to prevent the accumulation of inert gases; and the liquid phase in the first heat exchange product can flow back to the gas-liquid separation device through the reflux device at a mass reflux ratio of 0.1-50. Wherein, the reflux device can be a reflux tank; the first heat exchanger may be of the kind and form conventional in the art, such as a plate heat exchanger, a shell-and-tube heat exchanger, etc., and the disclosure does not make particular demands; the mass reflux ratio of the liquid phase in the first heat exchange product can be further preferably 0.2-20.

Further, in order to enhance the cooling effect of the first heat exchange product, the method may comprise: further cooling the first heat exchange product to obtain a cooled product comprising a gas phase and a liquid phase; returning at least a portion of the gas phase in the cooled product to the polymerization unit, likewise optionally another portion of the gas phase in the first heat exchanged product can be vented as a tail gas to prevent inert gas build-up; and refluxing the liquid phase in the cooled product to the gas-liquid separation device through the overhead reflux tank at a mass reflux ratio of 0.1-50, preferably 0.2-20.

In a specific embodiment of the present disclosure, the method may include: discharging a part of the liquid phase in the reflux unit from the reflux unit, preferably discharging light components in the liquid phase, to reduce the BF reflux to the gas-liquid separation unit₃Catalytic amount to increase BF₃Catalyst separation efficiency from polymerization reaction products.

In accordance with the present disclosure, the liquid phase product containing polyalphaolefin can be subjected to conventional post-treatment steps to obtain polyalphaolefin lubricant base oils, and in one embodiment of the present disclosure, the liquid phase product containing polyalphaolefin can be further subjected to hydrotreating to obtain paraffinic hydrocarbons useful as lubricant base oils, and the process of the present disclosure can further comprise: at least one part of the liquid phase product is heated and enters a hydrogenation system for hydrogenation treatment to obtain a hydrogenation product with reduced olefin content as a lubricating oil base oil primary product, and the hydrogenation product can be further subjected to a conventional treatment method to obtain the polyalphaolefin lubricating oil base oil. The conditions in which the hydrotreating is carried out may be reaction conditions conventional in the art, for example, the hydrogenation conditions may include: the reaction temperature is 200-400 ℃, preferably 220-380 ℃, the hydrogen partial pressure is 2-20 MPa, preferably 5-15 MPa, and the liquid hourly space velocity is 0.05-5 hours^-1Preferably 0.1 to 3 hours^-1The volume ratio of hydrogen to oil is 200 to 1000 standard cubic meters per cubic meter, preferably 300 to 800 standard cubic meters per cubic meter.

Further, to increase the heat utilization of the hydrogenated product, the process may comprise: and performing heat exchange treatment on the hydrogenation product and the liquid phase product in a second heat exchanger to use the hydrogenation product with higher temperature as a heating heat source of the gas-liquid separation device.

In accordance with the present disclosure, BF is increased for real-time monitoring of elemental F content in a polymerization reaction product₃The efficiency of the separation of the catalyst from the polymerization reaction product, the process may further comprise: measuring the content of the F element in the liquid phase product on line; when the content of the F element is higher than a limited standard, returning at least one part of the liquid-phase product to the gas-liquid separation device for gas-liquid separation; the mass reflux ratio of the liquid-phase product returned to the gas-liquid separation device can be 0.1-50, preferably 0.2-20, and when the reflux ratio is adjusted to be larger, the content of the F element in the liquid-phase product can not reach the limited standard, the separation temperature of the gas-liquid separation device can be adjusted; when the content of the F element does not exceed a defined standard, the liquid phase product can be directly subjected to hydrotreatment.

Wherein, the limiting standard of the content of the F element in the liquid phase product can be defined according to the requirements of the lubricating oil product, for example, the limiting standard can be that the content of the F element is not more than 100ppm, preferably not more than 10 ppm.

It is to be noted that, if not specifically required, the hydrogenation catalyst, the hydrogenation apparatus and the polymerization apparatus used in the method of the present invention may be any of those conventionally used in the art. For example, the hydrogenation catalyst may be a metal catalyst of a transition metal element, a metal oxide, a sulfide, a complex catalyst, or the like, and the hydrogenation apparatus and the polymerization reaction apparatus may be a fixed bed, a slurry bed, a tubular reactor, or the like.

In a second aspect of the present disclosure, there is provided a low viscosity polyalphaolefin lubricant base stock prepared according to the process of the first aspect of the present disclosure. The content of the F element in the poly alpha-olefin lubricating oil base oil is low.

In a third aspect of the present disclosure, there is provided a system for preparing a low-viscosity polyalphaolefin lubricant base oil, as shown in fig. 1, the system comprising a feed inlet, a polymerization reaction device 4, a gas-liquid separation device 5 and a discharge outlet; the feed inlet is communicated with a reactant inlet of the polymerization reaction device 4, a product outlet of the polymerization reaction device 4 is communicated with an inlet of the gas-liquid separation device 5, a liquid outlet of the gas-liquid separation device 5 is communicated with the discharge outlet, and a gas outlet of the gas-liquid separation device 5 is communicated with the reactant inlet of the polymerization reaction device 4.

According to the present disclosure, the gas-liquid separation device 5 may include at least one of a gas-liquid separation tower, a gas-liquid separation tank, and a heat exchanger, preferably the gas-liquid separation tower. The gas-liquid separation tower can be one of a pressurization separation tower, an atmospheric separation tower and a decompression separation tower, preferably the decompression separation tower, and the number of the tower plates of the gas-liquid separation tower can be 1-100, preferably 5-80.

Further, in order to reduce the content of the impurity elements in the product and ensure the quality of the product, the system can also comprise an online detection device for detecting the impurity elements in the heat exchange medium.

To further improve the gas-liquid separation efficiency, in one embodiment of the present disclosure, as shown in fig. 1, the system may further include a first heat exchanger 6 and a reflux device 8; the first inlet of the first heat exchanger 6 may be in communication with a gas outlet of the gas-liquid separation device 5, the second inlet of the first heat exchanger 6 may be in communication with a product outlet of the polymerization reaction device 4, the first outlet of the first heat exchanger 6 may be in communication with an inlet of the reflux device 8, the second outlet of the first heat exchanger 6 may be in communication with an inlet of the gas-liquid separation device 5, the liquid outlet of the reflux device 8 may be in communication with an inlet of the gas-liquid separation device 5 and optionally evacuated to discharge the inert gas, and the gas outlet of the reflux device 8 may be in communication with a reactant inlet of the polymerization reaction device 4 and optionally evacuated.

In this case, in order to further improve the gas-liquid separation efficiency, the system may further include a cooling device, and in this case, the first outlet of the first heat exchanger 6 may communicate with an inlet of the cooling device, and an outlet of the cooling device may communicate with an inlet of the reflux device 8.

According to the present disclosure, the liquid product of the gas-liquid separation device may be further hydrogenated to obtain a lubricant base oil initial product, in a specific embodiment of the present disclosure, the system may further include a hydrogenation device 10, an inlet of the hydrogenation device 10 may be communicated with the liquid outlet of the gas-liquid separation device 5, and an outlet of the hydrogenation device 10 may be communicated with the discharge hole.

Further, in order to improve the heat utilization efficiency of the system, the system may further include a second heat exchanger 12, a first inlet of the second heat exchanger 12 may be communicated with the outlet of the hydrogenation device 10, a second inlet of the second heat exchanger 12 may be communicated with the liquid outlet of the gas-liquid separation device 5, a first outlet of the second heat exchanger 12 may be communicated with the discharge port, and a second outlet of the second heat exchanger 12 may be communicated with the inlet of the hydrogenation device 10 and optionally the inlet of the gas-liquid separation device 5.

In a preferred embodiment of the present disclosure, the gas-liquid separation device may be a gas-liquid separation column, which may have a plurality of inlets, for example, including a feed inlet, an overhead reflux inlet and a bottom reflux inlet, and in the case where the system of the present disclosure includes the first heat exchanger 6 and the reflux device 8, the liquid outlet of the reflux device 8 may be communicated with the overhead reflux inlet of the gas-liquid separation column and optionally evacuated, which can further improve the efficiency of the gas-liquid separation; in the case that the system of the present disclosure includes the hydrogenation apparatus 10 and the second heat exchanger 12, the second outlet of the second heat exchanger 12 may be communicated with the inlet of the hydrogenation apparatus 10 and optionally communicated with the bottom reflux inlet of the gas-liquid separation tower, and at this time, the product of the hydrogenation apparatus may be used as a heating source of the bottom of the gas-liquid separation tower, so that the energy utilization rate of the system is improved.

The invention will be further illustrated by the following examples, but is not to be construed as being limited thereto. The instruments, devices and reagents used in the examples of the present invention are, unless otherwise specified, conventional in the art, and among them, BF is a group of instruments, devices and reagents used in the examples of the present invention₃The catalyst separation ratio is defined as: BF in overhead gas phase product₃Mass of BF3 was contained per mass of catalyst feed x 100%.

Example 1

As shown in fig. 1, the gas-liquid separation column 1 is employed as the gas-liquid separation means in this embodiment,the raw material containing alpha-olefin is 1-decene and contains BF₃In a catalyst of₃The content is 90%, the reaction auxiliary agent is 1-octanol, and the F content of the liquid phase product at the bottom of the tower is measured on line by adopting combustion ion chromatography (the specific method refers to ASTM D7359).

Starting material 1-decene of alpha-olefin, containing BF₃The catalyst, the circulating catalyst and the reaction auxiliary agent 1-octanol enter a polymerization reaction device 4 for polymerization reaction, and the reaction temperature is 25 ℃; the reaction pressure is 0.15 MPa; feed containing alpha-olefin, BF₃The molar ratio of the catalyst to the 1-octanol was 1: 0.01: 0.01, yield BF-containing₃The mixed product of the catalyst, 1-octanol and poly-1-decene is heated in a gas-liquid separation tower 5 (the number of tower plates is 8, the temperature of a tower kettle is 220 ℃) to carry out gas-liquid separation, and BF which mainly contains is obtained from the top of the tower and the bottom of the tower respectively₃A top gas phase product of the catalyst and the reaction aid and a bottom liquid phase product mainly containing polyalphaolefin;

carrying out heat exchange cooling on the tower top gas phase product and the mixed product in a first heat exchanger 6 to obtain a first heat exchange product, and further cooling the first heat exchange product in a cooler 7 to obtain a cooled product containing a gas phase and a liquid phase; at least a part of the gas phase in the cooled product is returned to the polymerization reaction device 4 after being compressed by the reflux tank 8 and the compressor 11, the rest of the gas phase is discharged as tail gas, the liquid phase in the cooled product is refluxed to the gas-liquid separation tower 5 by the mass reflux ratio of 1 through the reflux tank 8 at the top of the tower, and the light component of the liquid phase in the reflux tank 8 is discharged at random.

Measuring the content of F in the tower bottom liquid phase product on line, if the content of F is more than 10ppm, enabling the tower bottom liquid phase product to be completely re-pumped into an inlet of a gas-liquid separation tower 5 for separation, if the content of F is not more than 10ppm, enabling the tower bottom liquid phase product to be used as a qualified material to enter a hydrogenation system 10 for hydrogenation after being heated by a heating furnace 9, wherein the conditions of the hydrogenation are that the inlet hydrogen partial pressure is 10MPa, the reaction temperature is 270 ℃, and the volume space velocity is 0.8h^-1And the volume ratio of hydrogen to oil is 700, and the hydrogenation product is used as a heating heat source and sent into the second heat exchanger 12 to exchange heat with the tower bottom liquid of the gas-liquid separation tower 5.

According to the method of the embodiment, after stable operation, the mixed product enters gas-liquid separationThe treatment capacity of the separation tower is 1kg/h, and BF in the mixed product₃The separation rate of the catalyst was 100%, and the F content in the hydrogenated product was 0 ppm.

Example 2

The treatment was carried out in the same manner as in example 1 except that the overhead gas-phase product of the gas-liquid separation column 5 was directly returned to the polymerization reaction apparatus without passing through the first heat exchanger 6 and the cooler 7.

According to the method of the present example, after stable operation, the treatment amount of the mixed product into the gas-liquid separation column was 1kg/h, and BF was contained in the mixed product₃The separation rate of the catalyst was 99.99%, and the F content in the hydrogenated product was 2 ppm.

Comparative example 1

The process was carried out as in example 1, except that the polymerization mixture was subjected to alkali washing and water washing to separate polyalphaolefin and BF₃The catalyst can be specifically referred to.

According to the method of the comparative example, after stable operation, the treatment capacity of the mixed product entering the gas-liquid separation tower is 1kg/h, and BF in the mixed product₃The separation rate of the catalyst was 99.999% and the F content in the hydrogenated product was 10 ppm.

As can be seen from the data of examples 1-2 and comparative example 1, the process of the present disclosure enables the polymerization of alpha-olefins and BF₃The catalyst is continuously and effectively separated, manual intermittent material pouring is not needed, the treatment speed of the mixed product is high, the content of the polymerization product F reaches the standard, and F-containing wastewater is not generated. Moreover, when the gas-phase product at the top of the gas-liquid separation tower returns to the polymerization reaction device after heat exchange and the liquid-phase product at the bottom of the gas-liquid separation tower monitors the content of F on line to ensure that the unqualified liquid-phase product at the bottom of the gas-liquid separation tower refluxes, the BF can be further improved₃The separation rate of the catalyst and the quality of the polymerization reaction product.

The preferred embodiments of the present disclosure are described in detail with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and the simple modifications all belong to the protection scope of the present disclosure

It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. In order to avoid unnecessary repetition, various possible combinations will not be separately described in this disclosure.

In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.

Claims

1. A process for preparing a low viscosity polyalphaolefin lubricant base stock comprising the steps of:

(1) reacting a feed containing an alpha-olefin with a feed containing BF₃The catalyst and the reaction auxiliary agent are subjected to polymerization reaction in a polymerization reaction device to obtain the product containing BF₃A mixed product of a catalyst, a reaction aid and a polyalphaolefin; the reaction auxiliary agent is at least one of alcohol with 1-20 carbon atoms, ether with 1-20 carbon atoms, carboxylic acid with 1-20 carbon atoms, ester with 1-20 carbon atoms and phenol with 1-20 carbon atoms, the alpha-olefin raw material is alpha-olefin with C6-C14, and the reaction temperature of the polymerization reaction is 25-100 ℃;

(2) the mixed product is sent into a gas-liquid separation device to be heated for gas-liquid separation, and BF is mainly contained₃A gas phase product of the catalyst and a liquid phase product comprising predominantly polyalphaolefin; and

(3) returning at least a portion of the gas-phase product to the polymerization reaction unit;

the method further comprises the following steps: exchanging heat between the gas-phase product and the mixed product in a first heat exchanger to obtain a first heat exchange product containing a gas phase and a liquid phase;

returning at least a portion of the gas phase in the first heat exchanged product to the polymerization reaction unit and discharging another portion of the gas phase in the first heat exchanged product as a tail gas; enabling a liquid phase in the first heat exchange product to flow back to the gas-liquid separation device through a reflux device at a mass reflux ratio of 0.1-50;

further cooling said first heat exchanged product to obtain a cooled product comprising a gas phase and a liquid phase;

returning at least a portion of the gas phase in the cooled product to the polymerization reaction unit and discharging another portion of the gas phase in the cooled product as a tail gas; and refluxing the liquid phase in the cooling product to the gas-liquid separation device through a reflux device at a mass reflux ratio of 0.1-50.

2. The method of claim 1, wherein the gas-liquid separation device comprises at least one of a gas-liquid separation column, a gas-liquid separation tank, and a heat exchanger.

3. The method according to claim 2, wherein the gas-liquid separation column is one of a pressurized separation column, an atmospheric separation column and a vacuum separation column, and the number of the gas-liquid separation column plates is 1 to 100.

4. The method according to claim 2, wherein the gas-liquid separation tower has a bottom temperature of 50 to 400 ℃.

5. The process according to claim 1, wherein the polymerization conditions comprise: the reaction pressure is 10 Pa-5 MPa; said alpha-olefin feedstock, said BF₃The molar ratio of the catalyst to the reaction auxiliary agent is 1: (0.001-0.2): (0.001-0.4).

6. The method of claim 1, further comprising:

measuring the content of the F element in the liquid-phase product on line;

when the content of the F element is higher than a defined standard, returning at least one part of the liquid-phase product to the gas-liquid separation device for gas-liquid separation, and adjusting the separation temperature of the gas-liquid separation device;

when the content of the F element does not exceed the defined standard, directly subjecting the liquid phase product to hydrotreatment.

7. The method of claim 6, wherein the defined criterion is an elemental F content of no greater than 100 ppm.

8. The method of claim 1, further comprising: a portion of the liquid phase in the reflux unit is discharged from the reflux unit.

9. The method of claim 1, further comprising: and heating at least one part of the liquid phase product, and then, introducing the heated liquid phase product into a hydrogenation system for hydrogenation treatment to obtain a hydrogenation product with reduced olefin content and serving as the initial product of the lubricating oil base oil.

10. The method of claim 9, further comprising: and (3) carrying out heat exchange treatment on the hydrogenation product and the liquid-phase product in a second heat exchanger.

11. A low viscosity polyalphaolefin lubricant base stock prepared by the process of any one of claims 1 to 10.

12. A system for preparing low-viscosity poly-alpha-olefin lubricating oil base oil is characterized by comprising a feeding hole, a polymerization reaction device, a gas-liquid separation device and a discharging hole; the feed inlet is communicated with a reactant inlet of the polymerization reaction device, a product outlet of the polymerization reaction device is communicated with an inlet of the gas-liquid separation device, a liquid outlet of the gas-liquid separation device is communicated with the discharge outlet, and a gas outlet of the gas-liquid separation device is communicated with the reactant inlet of the polymerization reaction device;

the system also includes a first heat exchanger and a reflux unit; a first inlet of the first heat exchanger is communicated with a gas outlet of the gas-liquid separation device, a second inlet of the first heat exchanger is communicated with a product outlet of the polymerization reaction device, a first outlet of the first heat exchanger is communicated with an inlet of the reflux device, a second outlet of the first heat exchanger is communicated with an inlet of the gas-liquid separation device, a liquid outlet of the reflux device is communicated with the inlet of the gas-liquid separation device and is emptied, and a gas outlet of the reflux device is communicated with a reactant inlet of the polymerization reaction device and is emptied;

the system further comprises a cooling device, wherein the first outlet of the first heat exchanger is communicated with the inlet of the cooling device, and the outlet of the cooling device is communicated with the inlet of the backflow device.

13. The system of claim 12, wherein the gas-liquid separation device comprises at least one of a gas-liquid separation column, a gas-liquid separation tank, and a heat exchanger.

14. The system of claim 13, wherein the gas-liquid separation column is one of a pressurized separation column, an atmospheric separation column, and a reduced pressure separation column, and the gas-liquid separation column has 1 to 100 plates.

15. The system of claim 12, further comprising an in-line detection device for detecting impurity elements in the heat exchange medium.

16. The system of claim 12, further comprising a hydrogenation unit, wherein an inlet of the hydrogenation unit is in communication with the liquid outlet of the gas-liquid separation device, and an outlet of the hydrogenation unit is in communication with the discharge port.

17. The system of claim 16, further comprising a second heat exchanger, wherein a first inlet of the second heat exchanger is in communication with the outlet of the hydrogenation apparatus, a second inlet of the second heat exchanger is in communication with the liquid outlet of the gas-liquid separation apparatus, a first outlet of the second heat exchanger is in communication with the discharge port, and a second outlet of the second heat exchanger is in communication with the inlet of the hydrogenation apparatus and the inlet of the gas-liquid separation apparatus.