Device and method for producing poly alpha-olefin by continuous method
阅读说明：本技术 连续法生产聚α-烯烃的装置及方法 (Device and method for producing poly alpha-olefin by continuous method ) 是由 刘健 聂毅强 李方尧 于 2018-06-21 设计创作，主要内容包括：本发明公开了一种连续法生产聚α-烯烃的装置及方法,包括催化剂配制器,罐体外围设有第一冷却夹套；多级反应器包括相互串联的多个反应器,第一级为搅拌釜式反应器,其余为搅拌釜式反应器或者管式反应器；第一级反应器的釜体外围设置有第二冷却夹套,内部设有内置盘管；其余反应器的器壁外围均设有冷却夹套；催化剂计量泵与催化剂配制器和第一级反应器连通；冷冻水单元包括冷冻机组和与冷冻机组连通的冷冻水供水管和回水管,冷冻水供水管和回水管均与所有冷却夹套和内置盘管连通,形成多个外循环。本发明的连续法生产聚α-烯烃的装置及生产方法填补了国内商业化生产聚α-烯烃(PAO)的空白,能够实现大规模生产PAO合成油初产物。(The invention discloses a device and a method for producing poly-alpha-olefin by a continuous method, comprising a catalyst preparation device, wherein the periphery of a tank body is provided with a first cooling jacket; the multistage reactor comprises a plurality of reactors which are connected in series, the first stage is a stirred tank reactor, and the rest are stirred tank reactors or tubular reactors; a second cooling jacket is arranged at the periphery of the kettle body of the first-stage reactor, and a built-in coil pipe is arranged inside the kettle body; cooling jackets are arranged on the peripheries of the walls of the other reactors; the catalyst metering pump is communicated with the catalyst preparation device and the first-stage reactor; the chilled water unit comprises a refrigerating unit and a chilled water supply pipe and a water return pipe which are communicated with the refrigerating unit, wherein the chilled water supply pipe and the water return pipe are communicated with all cooling jackets and built-in coil pipes to form a plurality of external circulations. The device and the production method for producing the poly-alpha-olefin by the continuous method fill the blank of domestic commercial production of the poly-alpha-olefin (PAO), and can realize large-scale production of the PAO synthetic oil primary product.)
1. An apparatus for producing polyalphaolefins in a continuous process, the apparatus comprising:
the catalyst preparation device is characterized in that a first cooling jacket is arranged on the periphery of a tank body of the catalyst preparation device, and a cooling cavity is formed between the first cooling jacket and the tank body;
the multistage reactor comprises a plurality of reactors which are connected in series, and a discharge pump is arranged between every two adjacent reactors; wherein, the first stage of the reactors is a stirred tank reactor, and the rest are stirred tank reactors or tubular reactors; a second cooling jacket is arranged on the periphery of the kettle body of the first-stage reactor, a cooling cavity is formed between the second cooling jacket and the kettle body, and a built-in coil is arranged inside the second cooling jacket; cooling jackets are arranged on the peripheries of the walls of the other reactors, and cooling cavities are formed between the cooling jackets and the walls of the reactors;
the catalyst metering pump is communicated with the catalyst preparation device and the first-stage reactor;
the chilled water unit comprises a refrigerating unit and a chilled water supply pipe and a chilled water return pipe which are communicated with the refrigerating unit, wherein the chilled water supply pipe and the chilled water return pipe are communicated with all cooling jackets and built-in coils to form a plurality of external circulations.
2. The apparatus of claim 1, wherein the catalyst formulator is two.
3. The device of claim 1, wherein the catalyst dispenser comprises a tank and a first stirring mechanism, wherein the first stirring mechanism comprises a stirring shaft extending vertically downward from the top of the tank to the bottom of the tank, a stirring paddle arranged on the stirring shaft, and a power unit driving the stirring shaft and the stirring paddle to rotate; the tank body is also provided with a catalyst feed inlet, an accelerant feed inlet, a material outlet, a temperature measuring port and a liquid level measuring port.
4. The device of claim 1, wherein the stirred tank reactor comprises a tank body and a second stirring mechanism, the second stirring mechanism comprises a stirring shaft extending vertically downwards from the top of the tank body to the bottom of the tank body, a stirring paddle arranged on the stirring shaft, and a power unit driving the stirring shaft and the stirring paddle to rotate; the tank body is also provided with an alpha-olefin feed inlet, a catalyst feed inlet, a material outlet, a temperature measuring port and a liquid level measuring port.
5. The apparatus of claim 1, wherein the internal surface area of the internal coil is not less than the internal surface area of the second cooling jacket; preferably, the internal surface area of the built-in coil is (1-5) S based on the internal surface area S of the second jacket.
6. The apparatus according to claim 1, wherein the length to diameter ratio of the tubular reactor is equal to or greater than 50, preferably equal to or greater than 1000.
7. The apparatus of claim 1, further comprising a level controller and/or a temperature controller for monitoring a liquid level and/or a temperature in the catalyst formulator and multistage reactor.
8. A method for producing polyalphaolefins using the apparatus of any one of claims 1 to 7, comprising:
mixing a catalyst and an accelerant in a catalyst preparation device to obtain a catalyst complex, allowing the catalyst complex to enter a first-stage reactor through a catalyst metering pump, performing a first-stage polymerization reaction with alpha-olefin dissolved and mixed with the catalyst, and allowing an obtained first-stage polymerization product to enter a subsequent reactor through a discharge pump to finally obtain poly-alpha-olefin;
wherein, the heat generated in the catalyst preparation device and each stage of reactor is removed through a chilled water unit;
the catalyst is preferably formulated in a batch process.
9. The process according to claim 8, wherein the first stage polymerization has an α -olefin conversion of 20-85%, preferably 40-80%;
the pressure in the tank body of the catalyst preparation device is 0.01-0.5MPag, the preparation temperature is 10-40 ℃, and the temperature is preferably the same as the first polymerization reaction temperature;
the first stage polymerization reaction is carried out under the pressure of 0.01-0.5MPag, at the temperature of 10-40 ℃, preferably 20-30 ℃ and for 1.0-2.0h, and the adding amount of the catalyst is 0.3-3 wt% of the total amount of reactants.
10. The method of claim 8, wherein,
the alpha-olefin is C6-C14Preferably 1-decene and/or 1-decene with at least one C8-C12The mixture of alpha-olefins of (1), the content of 1-decene in the mixture being 50 mol% or more;
the catalyst is BF3The promoter is one or two proton donors, and the proton donor is C2To C8And/or C2To C8The carboxylic acid of (1) is preferably n-butanol.
Technical Field
The invention belongs to the field of alpha-olefin oligomerization, and particularly relates to a device and a method for producing poly-alpha-olefin by a continuous method.
Background
PAO (Poly-Alpha-Olefin) base oil is a product (dimer, trimer, tetramer and the like) obtained by oligomerization of linear Alpha-Olefin (usually 1-decene, and also 1-hexene to 1-tetradecene mixed Alpha-Olefin), is the most important IV synthetic lubricating oil base oil, has the characteristics of high viscosity index, low pour point, high flash point, good stability and thermal oxidation, excellent high and low temperature performance, long service life and the like, and is particularly suitable for the industries of aerospace, military, transportation, cosmetics and the like. The PAO synthetic oil has the advantages of low viscosity, medium and high viscosity and ultrahigh viscosity, wherein the low viscosity PAO accounts for about 70-80% of the PAO market, the low viscosity PAO is mainly produced by taking BF3 and proton donor promoter as catalysts, the production process technology and products are mainly concentrated in several companies in Europe and America, the production process technology and the products are strictly kept secret, and the similar commercialized process technology is not available in China.
It is well known that the oligomerization of alpha-olefins to poly-alpha-olefins (PAO) is a cationic polymerization, Lewis acid (BF)3、AlCl3Etc.) are commonly used cationic initiators, but pure lewis acids have low initiating activity and must form complexes and ion pairs with proton donor promoters to initiate oligomerization. Catalyst BF3Or initiator, and co-initiator or accelerator (HA) will give off heat during the complexation process. BF (BF) generator3The accelerator-initiated oligomerization cationic polymerization of alpha-olefins is an exothermic reaction, the main products being trimers and tetramers, the higher the alpha-olefin conversion the better. Maintaining uniform and stable reaction conditions is a key technical problem in production, which includes thorough mixing of the reaction system, withdrawal of reaction heat, temperature control, and the like.Commercial PAO plants operating continuously are generally larger in scale, larger plants are configured with larger reactor volumes, and large volume stirred tank reactors have difficulties in mixing and heat removal, and a wider distribution of reaction residence times affects product composition.
Disclosure of Invention
The invention aims to provide a device and a method for producing poly-alpha-olefin by a continuous method, which can realize large-scale industrial production of PAO synthetic oil primary products, can effectively regulate and control reaction conditions and final product composition, and can produce various low-viscosity PAO synthetic oil primary products.
In order to accomplish the above objects, an aspect of the present invention provides an apparatus for producing polyalphaolefins by a continuous process, the apparatus comprising:
the catalyst preparation device is characterized in that a first cooling jacket is arranged on the periphery of a tank body of the catalyst preparation device, and a cooling cavity is formed between the first cooling jacket and the tank body;
the multistage reactor comprises a plurality of reactors which are connected in series, and a discharge pump is arranged between every two adjacent reactors; wherein, the first stage of the reactors is a stirred tank reactor, and the rest are stirred tank reactors or tubular reactors; a second cooling jacket is arranged on the periphery of the kettle body of the first-stage reactor, a cooling cavity is formed between the second cooling jacket and the kettle body, and a built-in coil is arranged inside the second cooling jacket; cooling jackets are arranged on the peripheries of the walls of the other reactors, and cooling cavities are formed between the cooling jackets and the walls of the reactors;
the catalyst metering pump is communicated with the catalyst preparation device and the first-stage reactor;
the chilled water unit comprises a refrigerating unit and a chilled water supply pipe and a chilled water return pipe which are communicated with the refrigerating unit, wherein the chilled water supply pipe and the chilled water return pipe are communicated with all cooling jackets and built-in coils to form a plurality of external circulations.
Another aspect of the present invention provides a method for producing polyalphaolefin using the above apparatus, the method comprising:
mixing a catalyst and an accelerant in a catalyst preparation device to obtain a catalyst complex, and feeding the catalyst complex into a first-stage reactor through a catalyst metering pump; carrying out first-stage polymerization reaction with the alpha-olefin dissolved and mixed with the catalyst, and feeding the obtained first-stage polymerization product into a subsequent reactor through a discharge pump to finally obtain poly alpha-olefin;
wherein the heat generated in the catalyst formulator and the reactors of each stage is withdrawn by a chilled water unit.
The technical scheme of the invention has the following advantages:
the device and the production method for producing the poly-alpha-olefin by the continuous method fill the blank of domestic commercial production of the poly-alpha-olefin (PAO), and can realize large-scale production of the PAO synthetic oil primary product.
The device of the invention carries out batch preparation of the catalyst complex by the catalyst preparation device, continuously and accurately meters the catalyst complex by the catalyst metering pump, controls the conversion rate of alpha-olefin and the composition of a target PAO product by combining a multistage reactor and flexibly regulating and controlling each reaction parameter, and withdraws the heat of the complex reaction and the polymerization reaction by cooling jacket and/or chilled water flowing in a built-in coil.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Drawings
The above and other objects, features and advantages of the present invention will become more apparent by describing in more detail exemplary embodiments thereof with reference to the attached drawings.
Fig. 1 shows a schematic diagram of an apparatus for producing polyalphaolefin according to the continuous process of example 1 of the present invention.
Fig. 2 shows a schematic diagram of an apparatus for producing polyalphaolefin according to the continuous process of example 2 of the present invention.
Description of the reference numerals
1. A first stirring mechanism; 2. a catalyst preparation device; 3. a catalyst metering pump; 4. a first stage reactor; 5. a second stirring mechanism; 6. a discharge pump; 7. a second stage reactor.
Detailed Description
Preferred embodiments of the present invention will be described in more detail below. While the following describes preferred embodiments of the present invention, it should be understood that the present invention may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
An aspect of the present invention provides an apparatus for producing polyalphaolefin in a continuous process, the apparatus comprising:
the catalyst preparation device is characterized in that a first cooling jacket is arranged on the periphery of a tank body of the catalyst preparation device, and a cooling cavity is formed between the first cooling jacket and the tank body;
the multistage reactor comprises a plurality of reactors which are connected in series, and a discharge pump is arranged between every two adjacent reactors; wherein, the first stage of the reactors is a stirred tank reactor, and the rest are stirred tank reactors or tubular reactors; a second cooling jacket is arranged on the periphery of the kettle body of the first-stage reactor, a cooling cavity is formed between the second cooling jacket and the kettle body, and a built-in coil is arranged inside the second cooling jacket; cooling jackets are arranged on the peripheries of the walls of the other reactors, and cooling cavities are formed between the cooling jackets and the walls of the reactors;
the catalyst metering pump is communicated with the catalyst preparation device and the first-stage reactor;
the chilled water unit comprises a refrigerating unit and a chilled water supply pipe and a chilled water return pipe which are communicated with the refrigerating unit, wherein the chilled water supply pipe and the chilled water return pipe are communicated with all cooling jackets and built-in coils to form a plurality of external circulations.
As a preferred scheme, at most three layers of inner coil pipes are arranged in the kettle body of the stirred-kettle type reactor.
The multistage reactor in the present invention is preferably two-stage or three-stage.
In the invention, low-temperature water for heat removal is provided by a refrigerating unit, the temperature of the sent low-temperature water is 5-20 ℃, and the low-temperature water is respectively sent to a first cooling jacket of a catalyst preparation device, a cooling jacket of a multistage reactor and an inner coil of a reaction kettle through low-temperature water pipelines. The flow rate of the low-temperature water is determined by the temperature in each device and is controlled by a regulating valve, and the purpose is to stably control the temperature in each reaction kettle and reduce the temperature fluctuation of the polymerization reaction. The low-temperature water backwater returns to the refrigerating unit for recycling.
In the invention, the catalyst complex is prepared by adopting the catalyst preparation device with the cooling jacket, so that the heat removal problem of the complex reaction can be solved. The first-stage reactor adopts a stirred tank reactor with a heat removal jacket and an inner coil pipe, so that the full mixing of a polymerization reaction system can be ensured, and the effective withdrawal of reaction heat and the control of reaction temperature are realized. A multistage reactor is adopted for polymerization reaction, the polymerization reaction is divided into a plurality of reactors, the distribution of reaction residence time is improved, and an ideal PAO product composition is finally obtained; solves the problems that the mixing and heat removal are difficult and the distribution of reaction residence time is wider to influence the product composition by adopting a single large-volume stirred tank reactor.
In the present invention, the number of the catalyst formulators may be one or more, and as a preferred embodiment, the number of the catalyst formulators is two. When the device carries out continuous reaction, the catalyst is prepared by adopting an intermittent batch preparation method.
Two catalyst preparation devices are adopted to prepare initiator BF for oligomerization reaction in batch3-a promoter complex, continuously feeding the catalyst complex to the multistage reactor by means of a catalyst metering pump to initiate the reaction. Two catalyst formulators feed the reactor one and formulate the catalyst complex one to achieve alternating feeding of the catalyst complex into the multistage reactor.
As a preferred embodiment, the catalyst formulator comprises a tank body and a first stirring mechanism, wherein the first stirring mechanism comprises a stirring shaft vertically extending downwards from the top of the tank body to the bottom of the tank body, a stirring paddle arranged on the stirring shaft and a power unit driving the stirring shaft and the stirring paddle to rotate; the tank body is also provided with a catalyst feed inlet, an accelerant feed inlet, a material outlet, a temperature measuring port and a liquid level measuring port.
As a preferred embodiment, the stirred tank reactor comprises a tank body and a second stirring mechanism, wherein the second stirring mechanism comprises a stirring shaft vertically extending downwards from the top of the tank body to the bottom of the tank body, a stirring paddle arranged on the stirring shaft, and a power unit driving the stirring shaft and the stirring paddle to rotate; the tank body is also provided with an alpha-olefin feed inlet, a catalyst feed inlet, a material outlet, a temperature measuring port and a liquid level measuring port.
Preferably, the stirring paddle is a multilayer stirring paddle, and further preferably, the stirring paddle (4) is a 2-4-layer stirring paddle; the height H of the kettle body (1) is used as a reference, the distance between the stirring paddle at the lowest layer and the bottom of the kettle body (1) is H/4-H/3, and the distance between the stirring paddle at the uppermost layer and the bottom of the kettle body (1) is 2H/5-3H/5.
In the invention, the power unit is a variable frequency motor, and the control rotating speed range is 30-300 rpm.
As a preferred embodiment, the internal surface area of the internally disposed coil is not less than the internal surface area of the second cooling jacket; preferably, the internal surface area of the built-in coil is (1-5) S based on the internal surface area S of the second jacket.
In a preferred embodiment, the length/diameter ratio of the tubular reactor is greater than or equal to 50, preferably greater than or equal to 1000.
In the invention, from the viewpoint of reducing back mixing, the reactors except the first-stage reactor are preferably tubular reactors, the larger the length-diameter ratio is, the better the length-diameter ratio is, the material back mixing is reduced, the length-diameter ratio is at least 50, and the length-diameter ratio is preferably more than 1000. The volume and length to diameter ratio of the tubular reactor can be adjusted as desired by those skilled in the art to achieve the desired conversion of alpha-olefins.
As a preferred embodiment, the apparatus further comprises a level controller and/or a temperature controller for monitoring the liquid level and/or temperature in the catalyst dispenser and the multistage reactor, respectively.
Another aspect of the present invention provides a method for producing polyalphaolefin using the above apparatus, the method comprising:
mixing a catalyst and an accelerant in a catalyst preparation device to obtain a catalyst complex, allowing the catalyst complex to enter a first-stage reactor through a catalyst metering pump, performing a first-stage polymerization reaction with alpha-olefin dissolved and mixed with the catalyst, and allowing an obtained first-stage polymerization product to enter a subsequent reactor through a discharge pump to finally obtain poly-alpha-olefin;
wherein the heat generated in the catalyst formulator and the reactors of each stage is withdrawn by a chilled water unit.
According to the present invention, preferably, the catalyst formulation is a batch formulation process. I.e. more than two catalyst formulators are employed.
According to the present invention, preferably, the first stage polymerization has an α -olefin conversion of 20 to 85%, preferably 40% to 80%;
in the present invention, the α -olefin conversion and product composition of each reactor can be independently controlled. The alpha-olefin conversion in the first reactor can be adjusted in the range of 20-85%, but desirably at least 40% or more, preferably 40-80% from the standpoint of mixing and heat removal.
From the viewpoint of production efficiency, it is desirable that the total conversion of the α -olefin in the first reactor is as high as possible, but if the target product is to produce as much trimer as possible, the total conversion is controlled to be lower, preferably 40% to 80%, in which case the catalyst and the α -olefin are supplemented to the second reactor as necessary.
The pressure in the tank body of the catalyst preparation device is 0.01-0.5MPag, the preparation temperature is 10-40 ℃, and the temperature is preferably the same as the first polymerization reaction temperature;
in the invention, the preparation process of the catalyst complex comprises the steps of firstly adding a quantitative liquid accelerator into a preparation tank, and introducing BF while stirring3Controlling the pressure of the preparation tank to be 0.01-0.5MPag to ensure BF3Dissolved in a promoter to form BF3HA Complex, preparation temperature 10-40 ℃, preferably the same as the first polymerization temperature. Preferably, the batch is dosed at least in an amount sufficient to polymerize for more than half a day.
The pressure of the first-stage polymerization reaction is 0.01-0.5MPag, the temperature is 10-40 ℃, preferably 20-30 ℃, the time is 1.0-2.0h, and the adding amount of the catalyst is 0.3-3 wt% of the total amount of reactants; too small and too large amount of catalyst added is not favorable for production.
In the invention, the first stage reactor is continuously added with BF which is saturated and dissolved in advance3Or the alpha-olefin and the catalyst complex, or the alpha-olefin and BF are added separately and continuously3And a catalyst complex, the gas phase pressure is controlled to be 0.01-0.5MPag, the reaction temperature is controlled to be 10-40 ℃, the reaction temperature is preferably 20-30 ℃, and the reaction time is usually 1-1.5 h. The reaction residence time and the reaction rate are key parameters influencing the oligomerization degree of the alpha-olefin in the first-stage reactor, and the oligomerization degree and the product composition are controlled by adjusting the parameters of the alpha-olefin and the catalyst feeding amount, the reaction temperature, the reaction liquid level and the like of the first reactor. The reaction heat is withdrawn by the chilled water flowing through the cooling jacket and the inner coil, and the temperature of the reactor is controlled by regulating and controlling the flow of the chilled water flowing through the inner coil.
In the present invention, the alpha-olefin is C6-C14Preferably 1-decene and/or 1-decene with at least one C8-C12The mixture of alpha-olefins of (1), the content of 1-decene in the mixture being 50 mol% or more;
the catalyst is BF3The promoter is one or two proton donors, and the proton donor is C2To C8And/or C2To C8The carboxylic acid of (1) is preferably n-butanol.
The PAO synthetic oil initial product prepared by the invention is separated from unreacted alpha-olefin in a separation unit at the downstream of polymerization and recycled to the first-stage reactor. The PAO synthetic oil products with different brands can be prepared by hydrogenating and saturating the primary product of the PAO synthetic oil.
The invention is further illustrated by the following examples: