A process and system for the production of polyethers in batch mode and the polyethers obtained

Abstract

This invention discloses a system and method for batch production of polyether, and the resulting polyether. The system includes a reactor, within which a cooling inner coil, a temperature detector, and a pressure detector are installed. A cooling medium inlet line and a cooling medium outlet line are installed on the cooling inner coil, and a flow control valve V1 is installed on the cooling medium outlet line. A reaction product outlet line is located at the bottom of the reactor, and a reaction product circulation line is located between the bottom and top of the reactor or between the bottom and upper part of the reactor. This invention mainly solves problems such as maximizing reactor efficiency, automating feeding, and coupling temperature and pressure control with feed control in the batch polyether process.

Description

Technical Field

[0001] This invention belongs to the field of polyether production, and particularly relates to the batch process for producing polyether, specifically to the control process and system for the batch process for producing polyether. Background Technology

[0002] Polyether is an important chemical raw material and a primary raw material for the production of polyurethane products. These products are widely used in high-resilience, self-skinning foams, elastomers, adhesives, and reaction injection molding, among other polymeric applications. The synthesis of polyether generally involves using low-molecular-weight compounds containing active hydrogen, such as polyols and polyamines, as initiators. In the presence of a catalyst, propylene oxide, ethylene oxide, tetrahydrofuran, or other epoxides undergo ring-opening polymerization to form a high-molecular-weight compound. The molecular weight, viscosity, and degree of unsaturation of the product depend on the reaction conditions and control strategies of the synthesis process, while the volatile matter and impurities depend on subsequent post-treatment processes such as hydrolysis and neutralization.

[0003] Polyether production processes can be mainly divided into two types: continuous and batch processes. Continuous production is limited in its application due to the inconvenience of changing products. Batch production generally uses a batch reactor, which has simpler equipment and processes, and facilitates product switching. However, it suffers from drawbacks such as poor batch product quality stability and high production costs. Nevertheless, the batch process remains the primary method used for polyether production worldwide. This is because the polyurethane industry requires a wide variety of polyethers, market demand for these polyethers fluctuates greatly, and product demand is difficult to predict, requiring manufacturers to frequently change the types of polyethers they produce.

[0004] CN108070082A discloses a method for preparing low-viscosity high-molecular-weight polyether polyols. This method uses a polymetallic cyanide complex catalyst to intermittently synthesize high-molecular-weight polyether polyols. By controlling the polymerization rate of epoxides and continuously adding small-molecule initiators, the viscosity of the polyether polyol can be kept at a low level. However, the reactor wall of this method is prone to sticking with high-molecular-weight polymers, which leads to increased viscosity and unstable quality when preparing the next batch of high-molecular-weight polyether.

[0005] CN101302287B discloses a continuous preparation method for low-unsaturation polyether polyols. This method prepares low-unsaturation polyether polyols by continuously adding a polymetallic cyanide complex catalyst, an initiator, and an oxidized olefin into a reactor. This method solves the technical problem of catalyst pre-activation in continuous production processes. However, this method does not have a strategy for controlling the viscosity of the product, which limits its use in practical applications.

[0006] CN116082619A discloses a batch production method for low-odor polyether polyols. This method utilizes the relative acidity difference between the initiator and the crude polyether polyol. Based on chemical equilibrium, alkali metal ions are transferred from the crude polyether to the small molecule alcohol. Then, based on the differences in hydrophilicity / hydrophobicity and density between the two, hydrophobic materials are used to separate them to obtain qualified polyether polyol products. The small molecule alcohol containing alkali metal ions can be used as an initiator to continue the reaction to prepare crude polyether. This method reduces the odor of the product from the source, and the alkali metal catalyst can be recycled, with no inorganic salt waste generated, shortening the production cycle and reducing costs.

[0007] CN215139926U discloses a reactor for batch production of polyether polyols. This reactor, by setting multiple feeding tanks at the top and a solenoid valve at the bottom, ensures that the operator can add materials reasonably according to the scale lines on the feeding tanks. At the same time, the reactor controller can achieve precise control of the amount of additives in the production materials of polyether polyols by controlling the operation of the solenoid valve, thus ensuring the production quality of polyether polyols.

[0008] CN218131843U discloses a reaction apparatus for batch production of polyether polyols. The reactor is equipped with a stirring scraper, which allows the raw materials to be automatically sprayed into the reactor in a ring shape while stirring, thus improving the mixing uniformity of the polymerization raw materials. At the same time, the polymerization raw materials are added in batches in this apparatus, mixing and adding simultaneously, without the need for manual operation, ensuring the preparation effect and efficiency of polyether polyols.

[0009] In summary, there are currently no patents or literature focusing on maximizing the energy efficiency of batch reactors, automated control of feed in batch reaction processes, and the coupling of temperature and pressure control with feed control. Summary of the Invention

[0010] To overcome the problems existing in the prior art, the present invention provides a system and method for producing polyether by batch process, as well as the obtained polyether, mainly solving problems such as maximizing reactor efficiency, automating feeding, and coupling temperature and pressure control with feed control in the batch process of polyether.

[0011] One objective of this invention is to provide a system for batch production of polyether, comprising a reactor, a cooling inner coil, a temperature detector, and a pressure detector disposed within the reactor; a cooling medium inlet line and a cooling medium outlet line disposed on the cooling inner coil; a flow control valve V1 (for controlling the discharge flow rate of the cooling medium on the cooling inner coil) disposed on the cooling medium outlet line; a reaction product outlet line disposed at the bottom of the reactor; a reaction product circulation line disposed between the bottom and top of the reactor or between the bottom and upper part of the reactor; an external circulation cooler disposed on the reaction product circulation line; a cooling medium inlet line and a cooling medium outlet line disposed on the external circulation cooler; and a flow control valve V2 (for controlling the discharge flow rate of the cooling medium on the external circulation cooler) disposed on the cooling medium outlet line.

[0012] In a preferred embodiment, the system further includes a first TC controller (HS1 in the figure), which is electrically connected to a temperature detector (TC in the figure) and a flow control valve V1 to form an electrical connection loop one, for controlling the opening degree of the flow control valve V1 by the temperature inside the reactor.

[0013] In a further preferred embodiment, the first TC controller controls the opening of the flow control valve V1 as follows: when the temperature detected by the temperature detector (TC in the figure) is higher than the set temperature T1, the opening of the flow control valve V1 is increased; when the temperature detected by the temperature detector (TC in the figure) is lower than the set temperature T1, the opening of the flow control valve V1 is decreased.

[0014] In a further preferred embodiment, after the alkyl epoxide feed is completed or after the flow control valve V3 is closed and T2 < reactor internal temperature ≤ 115°C (preferably T2 = 100°C to 113°C), the first TC controller type (IV) controls the flow control valve V1 to gradually close.

[0015] In a preferred embodiment, the system further includes a second TC controller (HS2 in the figure); wherein the second TC controller is electrically connected to a temperature detector (TC in the figure) and a flow control valve V2 to form an electrical connection loop two, for controlling the opening degree of the flow control valve V2 by temperature.

[0016] In a further preferred embodiment, the second TC controller controls the opening of the flow control valve V2 as follows: when the temperature detected by the temperature detector (TC in the figure) is higher than the set temperature T1, the opening of the flow control valve V2 is increased; when the temperature detected by the temperature detector (TC in the figure) is lower than the set temperature T1, the opening of the flow control valve V2 is decreased.

[0017] In a further preferred embodiment, after the alkyl epoxide feed is completed or after the flow control valve V3 is closed and 115°C < reactor internal temperature ≤ T1 (preferably T1 = 117°C ~ 130°C), the first TC controller controls the flow control valve V1 to gradually close via formula (IV).

[0018] In a preferred embodiment, a raw material feed line is provided at the top or upper part of the reactor.

[0019] In a further preferred embodiment, a flow control valve V3 is provided on the raw material feed pipeline to control the flow rate of the raw material feed.

[0020] In a preferred embodiment, the system further includes a TC-PC selection controller (HS3 in the figure), which is electrically connected to the temperature controller, the pressure controller and the flow control valve V3 to form an electrical connection loop three.

[0021] In a further preferred embodiment, the TC-PC selection controller receives a pressure signal from the pressure controller and then controls the opening degree of the flow control valve V3 according to the pressure signal:

[0022] (1) When the pressure inside the vessel is disturbed from the equilibrium state and P1 < the internal pressure P of the reactor (preferably ≤ P2), the TC-PC selector controller controls the opening of the flow control valve V3 by the pressure controller; (2) When the pressure inside the vessel is disturbed from the equilibrium state and 0.0 MPaG < the internal pressure P of the reactor ≤ P1, the TC-PC selector controller controls the opening of the flow control valve V3 by the temperature controller.

[0023] Wherein, P1 = 0.1–0.3 MPaG, P2 = 0.3–0.5 MPaG and excluding 0.3 MPaG (P2 is the highest pressure in experimental and industrial reaction processes), and P1 < P2. For example, P1 = 0.1 MPaG, 0.2 MPaG, or 0.3 MPaG, P2 = 0.3 MPaG, 0.4 MPaG, or 0.5 MPaG, P2 = 0.3 MPaG, 0.35 MPaG, 0.4 MPaG, 0.45 MPaG, or 0.5 MPaG.

[0024] In a further preferred embodiment, when the pressure inside the reactor is disturbed from its equilibrium state and P1 < the internal pressure P of the reactor (preferably ≤ P2), the TC-PC selection controller receives the pressure signal from the pressure controller and controls the opening of the flow control valve V3 according to formula (I):

[0025]

[0026] Where P0 represents the stable pressure value before the pressure disturbance, V3 opening 0 represents the valve opening value of V3 before the pressure disturbance, P represents the real-time pressure value inside the vessel after the disturbance, K1 is a constant value of 1 to 4 (e.g., 1, 2, 3 or 4), and n1 is a constant value of 1 to 4 (e.g., 1, 2, 3 or 4).

[0027] When P1 < the internal pressure of the reactor, formula (I) is used for control. Specifically: when the internal pressure of the reactor is disturbed from the equilibrium state, if the internal pressure increases (i.e., P > P0), the opening of V3 will decrease rapidly; if the internal pressure decreases (i.e., P < P0), the opening of V3 will increase rapidly. The greater the difference between P and P0, the larger the ratio, and the greater the change in the opening of V3. As P gradually approaches P0, the change in the opening of V3 will decrease. The constant n1 was determined by the inventors after extensive experimental research. It is used to amplify the proportional relationship between P and P0, facilitating a rapid return to a new equilibrium state.

[0028] In a further preferred embodiment, when the pressure inside the reactor is disturbed from its equilibrium state and 0.0 MPaG < reactor internal pressure P ≤ P1, the TC-PC selector receives the temperature change signal from the temperature controller and controls the opening of the flow control valve V3 according to formula (II):

[0029]

[0030] Wherein, V3 opening degree 0 represents the opening value of valve V3 before pressure disturbance, T0 represents the stable temperature value before temperature change, T1 represents the real-time temperature value inside the vessel after temperature change, K2 is a constant value of 1 to 4 (e.g., 1, 2, 3 or 4), and n2 is a constant value of 5 to 8 (e.g., 5, 6, 7 or 8). The inventors found through experiments that because temperature has a hysteresis effect, the value of n2 should be greater than that of n1.

[0031] When the pressure inside the reactor is disturbed from the equilibrium state and 0.0 MPaG < reactor internal pressure ≤ P1, formula (II) is used for control. Specifically: when the control system in the equilibrium state is disturbed, and the temperature rises (T > T0), the opening of V3 will decrease rapidly; when the temperature decreases (T < T0), the opening of V3 will increase rapidly; the greater the difference between T and T0, the greater the proportion, and the greater the change in the opening of V3. As T gradually approaches T0, the change in the opening of V will decrease. The constant n2 was determined by the inventors after extensive experimental research and is used to amplify the proportional relationship between T and T0, facilitating a rapid return to a new equilibrium state.

[0032] In a preferred embodiment, a flow controller FC is further provided on the raw material feed line for detecting the feed rate of the raw material.

[0033] In a further preferred embodiment, the flow controller FC and the flow control valve V3 are electrically connected to form an electrical connection loop four, wherein when the flow controller FC detects that the raw material feed rate has reached a set value (the feed rate required for the intermittent flow), it controls the flow control valve V3 to close.

[0034] In a preferred embodiment, a stirrer is further provided inside the reaction vessel.

[0035] In a preferred embodiment, a jacket is provided on the reactor for heating; preferably, steam or heat transfer oil is used for heating.

[0036] In a preferred embodiment, an external circulation pump is provided on the reaction product circulation pipeline.

[0037] The material inside the reactor is pressurized by an external circulation pump and then sent to an external circulation cooler for cooling before returning to the reactor.

[0038] A second objective of this invention is to provide a batch method for producing polyethers, using the system described in one objective of this invention, the method comprising:

[0039] (1) Add raw materials including basic polyether and catalyst into the reactor and heat it to the set temperature I (for example, heat the material through the jacket of the reactor and turn off the jacket heating after reaching the set temperature I).

[0040] (2) Epoxy alkane is introduced into the reactor through the raw material feed pipeline, wherein the opening of the flow control valve V3 is gradually opened to 10%≤V3≤40% (e.g. 10%, 15%, 20%, 25%, 30%, 35% or 40%), and the opening of the flow control valve V1 is controlled through the electrical connection circuit to control the temperature inside the reactor.

[0041] (3) Continue to gradually increase the opening of the flow control valve V3 to 40% < V3 ≤ 100% (preferably 40% < V3 ≤ 80%) to feed epoxide alkane. When the opening of the flow control valve V1 reaches 70% to 100%, control the opening of the flow control valve V2 through the electrical connection circuit II to control the temperature inside the reactor at the set temperature II.

[0042] (4) When the opening degree of flow control valve V2 reaches 60% to 100%, the opening degree of flow control valve V3 is controlled by electrical connection circuit three.

[0043] (5) When the feed rate of epoxide alkane reaches the set value, the flow control valve V3 is closed (stop feeding) through the electrical connection circuit four control.

[0044] In a preferred embodiment, in step (1), the molecular weight of the base polyether is 200 to 6000, preferably 200 to 4000, for example 200, 500, 800, 1000, 1200, 1500, 1800, 2000, 2200, 2500, 2800, 3000, 3200, 3500, 3800, 4000, 4500, 5000, 5500 or 6000.

[0045] In a preferred embodiment, in step (1), the catalyst is selected from commonly used catalysts for preparing polyethers in the art, such as one or more of sodium hydroxide (NaOH), potassium hydroxide (KOH), cesium hydroxide (CsOH), and dimethylamine hydrochloride.

[0046] In a preferred embodiment, the oxygen content in the reactor is controlled to be less than 150 ppm before step (1).

[0047] In a preferred embodiment, the set temperature I in step (1) is 90 to 110°C, preferably 95 to 110°C, for example 90°C, 95°C, 100°C, 105°C or 110°C.

[0048] In a preferred embodiment, in step (2), the flow control valve V3 is gradually opened to 20-35%, for example, 20%, 25%, 30% or 35%.

[0049] In a preferred embodiment, in step (2), the following control is performed through the electrical connection circuit: the first TC controller controls the opening of the flow control valve V1 according to the temperature inside the reactor, so as to control the temperature inside the reactor at the set temperature II.

[0050] In a further preferred embodiment, the set temperature II is 100-135°C, preferably 100-130°C, for example 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C or 135°C.

[0051] In a further preferred embodiment, the set temperature II is higher than the set temperature I.

[0052] In a preferred embodiment, in step (3), when the opening of the flow control valve V1 reaches 85% to 100% (e.g., 85%, 90%, 95% or 100%), the temperature inside the reactor is controlled at the set temperature II by the electrical connection circuit II.

[0053] In a further preferred embodiment, in step (3), the following control is performed through the electrical connection circuit two: the second TC controller controls the opening of the flow control valve V2 according to the temperature inside the reactor, so as to control the temperature inside the reactor at the set temperature II.

[0054] In a preferred embodiment, in step (4), when the opening degree of the flow control valve V2 reaches 70-90% (e.g., 70%, 75%, 80%, 85% or 90%), the opening degree of the flow control valve V3 is controlled by the electrical connection loop three.

[0055] In a preferred embodiment, in step (4), the electrical connection circuit three controls the opening of the flow control valve V3 in the following manner: the TC-PC selection controller receives a pressure signal from the pressure controller, and then controls the opening of the flow control valve V3 according to the pressure signal:

[0056] (1) When the pressure inside the reactor is disturbed from the equilibrium state and P1 < the internal pressure P of the reactor (preferably ≤ P2), the TC-PC selector controller controls the opening of the flow control valve V3 by the pressure controller; (2) When 0.0MPaG < the internal pressure P of the reactor ≤ P1, the TC-PC selector controller controls the opening of the flow control valve V3 by the temperature controller.

[0057] Wherein, P1 = 0.1–0.3 MPaG, P2 = 0.3–0.5 MPaG and excluding 0.3 MPaG (P2 is the highest pressure in experimental and industrial reaction processes), and P1 < P2. For example, P1 = 0.1 MPaG, 0.2 MPaG, or 0.3 MPaG, and P2 = 0.3 MPaG, 0.4 MPaG, or 0.5 MPaG.

[0058] The control method of the above-mentioned electrical connection circuit three can ensure that the entire reactor does not exceed the pressure (not exceeding P1).

[0059] In a further preferred embodiment, when the pressure inside the reactor is disturbed from its equilibrium state and P1 < the internal pressure P of the reactor (preferably ≤ P2), the TC-PC selector receives the pressure change signal from the pressure controller and controls the opening of the flow control valve V3 according to formula (I):

[0060]

[0061] Wherein, P0 represents the stable pressure value before the pressure disturbance, V3 opening 0 represents the stable valve opening value of V3 before the pressure disturbance, P represents the real-time pressure value inside the vessel after the disturbance, K1 is a constant value of 1 to 4 (e.g., 1, 2, 3 or 4), and n1 is a constant value of 1 to 4 (e.g., 1, 2, 3 or 4).

[0062] When too much alkyl epoxide is added, the amount of alkyl epoxide that can dissolve inside the reactor is limited, while the remainder exists in the gas phase space or as bubbles in the liquid phase system, causing the pressure inside the reactor to increase. In this case, pressure is used to control the rate of addition of alkyl epoxide.

[0063] In a further preferred embodiment: when the pressure inside the reactor is disturbed from the equilibrium state and 0.0 MPaG < reactor internal pressure P ≤ P1, the TC-PC selector receives the temperature change signal from the temperature controller and controls the opening of the flow control valve V3 according to equation (II):

[0064]

[0065] Wherein, V3 opening degree 0 represents the opening value of valve V3 before temperature disturbance, T0 represents the stable temperature value before temperature change (set temperature II), T represents the real-time temperature value inside the vessel after temperature disturbance, K2 is a constant value of 1 to 4 (e.g., 1, 2, 3 or 4), and n2 is a constant value of 5 to 8 (e.g., 5, 6, 7 or 8). The inventors found through experiments that because temperature has a hysteresis effect, the value of n2 should be greater than that of n1.

[0066] When the amount of alkyl epoxide added is less than the capacity that the system can withstand, the system temperature will gradually approach the lower limit of the reaction temperature range because the addition rate is less than the reaction rate. This will cause the system pressure to gradually decrease, thus reducing the utilization efficiency of the reactor. In this case, temperature is suitable for controlling the addition rate of alkyl epoxide.

[0067] In a preferred embodiment, in step (5), the electrical connection circuit four is controlled as follows: when the flow controller FC detects that the feed amount of alkyl epoxide reaches the set value, it controls the flow control valve V3 to close and stops the feed of alkyl epoxide.

[0068] In a preferred embodiment, in step (5), after closing the flow control valve V3, the flow control valve V2 and the flow control valve V1 are closed sequentially.

[0069] In a further preferred embodiment, after closing the flow control valve V3 in step (5), the following control continues:

[0070] (a) When 115°C < reactor internal temperature ≤ T1 (preferably T1 = 117°C ~ 130°C, for example 117°C, 120°C, 122°C, 124°C, 126°C, 128°C or 130°C), the second TC controller controls the flow control valve V2 to gradually close through the electrical connection loop two.

[0071] (b) When T2 < reactor internal temperature ≤ 115℃ (preferably T2 = 100℃ to 113℃, for example 100℃, 102℃, 104℃, 106℃, 108℃, 110℃, 111℃, 112℃ or 113℃), the first TC controller gradually closes the flow control valve V1 through an electrical connection loop.

[0072] In a further preferred embodiment, in step (a), the second TC controller controls the opening of the flow control valve V2 using equation (III) as follows:

[0073]

[0074] Where T0 represents the initial temperature value (set temperature II), T represents the real-time temperature value inside the vessel, V2 opening degree 0 refers to the valve V2 opening degree when the flow control valve V3 is closed, and K3 is a constant value of 8 to 12 (e.g., 8, 9, 10, 11 or 12).

[0075] In a further preferred embodiment, in step (b), the first TC controller controls the flow control valve V1 to gradually close via formula (IV):

[0076]

[0077] Where T0 represents the initial temperature value (set temperature II), T represents the real-time temperature value inside the vessel, V1 opening degree 0 refers to the opening degree of valve V1 when the flow control valve V3 is closed, and K4 is a constant value of 8 to 12.

[0078] In a preferred embodiment, the inlet and outlet temperature difference of the external circulation cooler is 2 to 15°C, preferably 2 to 10°C, for example 2°C, 4°C, 6°C, 8°C, 10°C, 12°C, 14°C or 15°C.

[0079] A third objective of this invention is to provide polyethers obtained using the system described in one objective of this invention or the method described in another objective of this invention.

[0080] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values; these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In the following, various technical solutions can, in principle, be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein.

[0081] Compared with the prior art, the present invention has the following beneficial effects:

[0082] (1) In this invention, the system or method described in this invention is used to control the feeding of epoxide alkane, which can avoid the problems of overheating due to excessive feeding and low reactor utilization and reduced efficiency of batch reactor due to insufficient feeding during the manual feeding process.

[0083] (2) In this invention, the batch production process can be automatically controlled from the start of feeding to the final reaction and product output;

[0084] (3) The batch process for producing polyether described in this invention solves the problems of low energy efficiency of existing batch reactors, safety risks of overheating and overpressure due to manual feeding, and coupling of temperature and pressure control with feed control. It has high reactor energy efficiency, automated feeding process, and coupling of temperature and pressure control with feed control to make the reaction process safe and stable. Attached Figure Description

[0085] Figure 1 A schematic diagram of the system described in this invention is shown;

[0086] exist Figure 1 In the diagram, 111 represents the reaction feed stream, 112 represents the reactor feed stream, 113 represents the reactor bottom discharge stream, 114 represents the pressurized stream, 115 represents the product stream, 116 represents the circulating stream, 117 represents the cooled circulating stream, 131 represents the cooling medium feed stream of the cooling inner coil, 132 represents the cooling medium discharge stream of the cooling inner coil, 133 represents the cooling medium feed stream of the external circulating cooler, 134 represents the cooling medium discharge stream of the external circulating cooler, E1 represents the external circulating cooler, R1 represents the reactor, P1 represents the external circulating pump, V1 represents the flow control valve V1 for the cooling medium discharge of the cooling inner coil, V2 represents the flow control valve V2 for the cooling medium discharge of the external circulating cooler, V3 represents the flow control valve V3 for the reactor feed stream, HS1 represents the first TC controller, HS2 represents the second TC controller, HS3 represents the TC-PC selection controller, and FC represents the flow controller FC for the reactor feed stream.

[0087] In this invention, the reaction feed stream 111 passes through the flow controller FC and the flow control valve V3 to obtain the reactor feed stream 112. Stream 112 enters the reactor R1, and the reactor bottom discharge stream 113 enters the external circulation pump P1 for pressurization to obtain the pressurized stream 114. The pressurized stream 114 is connected to the circulating stream 116 during the reaction process and sent to the external circulation cooler E1 to obtain the cooled circulating stream 117, which returns to the reactor R1. After the reaction is completed, when discharging, the pressurized stream 114 is connected to the product stream 115 during the reaction process.

[0088] Logistics 131 is the feed logistics for the cooling medium of the cooling inner coil, and logistics 132 is the discharge logistics for the cooling medium of the cooling inner coil. The flow rates of logistics 131 and 132 are adjusted by the flow control valve V1.

[0089] Logistics 133 is the feed logistics of the cooling medium for the external circulation cooler, and logistics 134 is the discharge logistics of the cooling medium for the external circulation cooler. The flow rates of logistics 133 and 134 are regulated by flow control valve V2. Detailed Implementation

[0090] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0091] It should also be noted that the various specific technical features described in the following embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the various possible combinations will not be described separately in this invention.

[0092] Furthermore, various embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention. The resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0093] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0094] In the examples, the reactor utilization rate was obtained as follows:

Example 1

[0095] A system for batch production of polyethers:

[0096] like Figure 1As shown, the system includes a reactor, inside which is installed a heat-reducing inner coil, a temperature detector TC, and a pressure detector PC. A heat-reducing medium inlet line and a heat-reducing medium outlet line are installed on the heat-reducing inner coil. A flow control valve V1 (for controlling the outflow rate of the heat-reducing medium from the heat-reducing inner coil) is installed on the heat-reducing medium outlet line. A reaction product outlet line is installed at the bottom of the reactor. A reaction product circulation line is installed between the bottom and top of the reactor. An external circulation cooler E1 is installed on the reaction product circulation line. A cooling medium inlet line and a cooling medium outlet line are installed on the external circulation cooler E1. A flow control valve V2 (for controlling the outflow rate of the cooling medium from the external circulation cooler) is installed on the cooling medium outlet line.

[0097] The system further includes a first TC controller HS1, which is electrically connected to a temperature detector TC and a flow control valve V1 to form an electrical connection loop one, and is used to control the opening degree of the flow control valve V1 by temperature.

[0098] The system further includes a second TC controller HS2; wherein the second TC controller is electrically connected to the temperature detector and the flow control valve V2 to form an electrical connection loop two, and is used to control the opening degree of the flow control valve V2 by temperature.

[0099] A raw material feed line is installed at the top of the reactor, and a flow control valve V3 is installed on the raw material feed line to control the flow rate of the raw material. The system further includes a TC-PC selector controller HS3, which is electrically connected to a temperature controller TC, a pressure controller PC, and a flow control valve V3 to form an electrical connection loop three. Equations (I) and (II) are configured within the TC-PC selector controller.

[0100] A flow controller FC is further installed on the raw material feed line to detect the feed rate of the raw material. The flow controller FC is electrically connected to the flow control valve V3 to form an electrical connection loop four. When the flow controller FC detects that the feed rate of the raw material reaches a set value (the feed rate required for the intermittent flow), it controls the flow control valve V3 to close.

[0101] A stirrer is further installed inside the reactor; a jacket is installed on the reactor for heating. An external circulation pump P1 is installed on the reaction product circulation pipeline. The material in the reactor is pressurized by the external circulation pump and sent to the external circulation cooler for cooling before returning to the reactor.

[0102]

Example 2

[0103] Using the system described in Example 1, temperature I was set to 95°C, temperature II to 100°C, the base polyether was a trifunctional polyether with a molecular weight of 2000, the catalyst was KOH, the epoxide was propylene oxide, the amount of base polyether was 12 wt%, the amount of catalyst was 0.34 wt%, and the amount of epoxide was 87.66 wt%. The oxygen content in the reactor was controlled to be less than 150 ppm.

[0104] The method includes:

[0105] (1) Add raw materials including basic polyether and catalyst into the reactor, and heat the materials through the jacket of the reactor until the set temperature I (105℃) is reached, then turn off the jacket heating.

[0106] (2) Epoxy alkane is introduced into the reactor through the raw material feed pipeline. The flow control valve V3 is gradually opened to 38%, and the flow control valve V1 is controlled through the electrical connection circuit to control the temperature in the reactor at the set temperature II.

[0107] (3) Continue to gradually increase the opening of the flow control valve V3 to 50% to feed the epoxide alkane. When the opening of the flow control valve V1 reaches 95%, the opening of the flow control valve V2 is controlled by the electrical connection circuit II, thereby controlling the temperature inside the reactor at the set temperature II.

[0108] (4) When the opening degree of flow control valve V2 reaches 85%, the opening degree of flow control valve V3 is controlled through electrical connection circuit three; in step (4), the opening degree of flow control valve V3 is controlled by electrical connection circuit three in the following manner:

[0109] The TC-PC selector receives a pressure signal from the pressure controller: when P1 < internal pressure of the reactor ≤ P2 (P1 = 0.3 MPaG, P2 = 0.48 MPaG), the TC-PC selector receives the pressure signal from the pressure controller and controls the opening of the flow control valve V3 according to formula (I), where K1 is 1 and n1 is 2.

[0110] When 0.0MPaG < reactor internal pressure ≤ 0.30MPaG, the TC-PC selector receives the temperature signal from the temperature controller and controls the opening of the flow control valve V3 according to formula (II). In formula (I), K2 is 1 and n2 is 5.

[0111] (5) When the feed rate of alkyl epoxides reaches the set value, the flow control valve V3 is closed via electrical connection loop four to stop the feed. In step (5), the electrical connection loop four performs the following control: when the flow controller FC detects that the feed rate of alkyl epoxides reaches the set value, it controls the flow control valve V3 to close to stop the feed of alkyl epoxides.

[0112] After closing the flow control valve V3 in step (5), the following control continues:

[0113] (a) When 115℃ < reactor internal temperature ≤ T1 (T1 = 120℃), the second TC controller controls the flow control valve V2 to gradually close according to formula (III), where K3 is 8;

[0114] (b) When T2 < reactor internal temperature ≤ 115℃ (T2 = 110℃), the first TC controller controls the flow control valve V1 to gradually close according to formula (IV), in which K4 is 8.

[0115] Throughout the entire process, the average temperature difference between the inlet and outlet of the external circulation cooler is 10°C.

[0116] The average number-average molecular weight of the obtained polyether product was 6200, the average molecular weight distribution was 3.0, the molecular weight distribution index deviation between batches of polyether product was ±2.48%, and the reactor utilization rate was 98.5%.

[0117]

Example 3

[0118] Using the system described in Example 1, temperature I was set to 100°C, temperature II to 110°C, the base polyether was a trifunctional polyether with a molecular weight of 2000, the catalyst was KOH, the epoxide was propylene oxide, the amount of base polyether was 8%, the amount of catalyst was 0.22%, and the amount of epoxide was 91.78%. The oxygen content in the reactor was controlled to be less than 150 ppm.

[0119] The method includes:

[0120] (1) Add raw materials including basic polyether and catalyst into the reactor, and heat the materials through the jacket of the reactor until the set temperature I is reached, then turn off the jacket heating.

[0121] (2) Epoxy alkane is introduced into the reactor through the raw material feed pipeline, wherein the flow control valve V3 is gradually opened to 29%, and the opening of the flow control valve V1 is controlled through the electrical connection circuit to control the temperature inside the reactor.

[0122] (3) Continue to gradually increase the opening of the flow control valve V3 to 65% to feed the epoxide alkane. When the opening of the flow control valve V1 reaches 88%, the opening of the flow control valve V2 is controlled by the electrical connection circuit II to control the temperature inside the reactor at the set temperature II.

[0123] (4) When the opening degree of flow control valve V2 reaches 76%, the opening degree of flow control valve V3 is controlled through electrical connection circuit three; in step (4), the opening degree of flow control valve V3 is controlled by electrical connection circuit three in the following manner:

[0124] The TC-PC selector receives a pressure signal from the pressure controller: when P1 < internal pressure of the reactor ≤ P2 (P1 = 0.25 MPaG, P2 = 0.45 MPaG), the TC-PC selector receives the pressure signal from the pressure controller and controls the opening of the flow control valve V3 according to formula (I), where K1 is 1 and n1 is 2.

[0125] When 0.0MPaG < reactor internal pressure ≤ P1 (P1 = 0.25MPaG), the TC-PC selector receives the temperature signal from the temperature controller and controls the opening of the flow control valve V3 according to formula (II). In formula (I), K2 is 1 and n2 is 5.

[0126] (5) When the feed rate of alkyl epoxides reaches the set value, the flow control valve V3 is closed via electrical connection loop four to stop the feed. In step (5), the electrical connection loop four performs the following control: when the flow controller FC detects that the feed rate of alkyl epoxides reaches the set value, it controls the flow control valve V3 to close to stop the feed of alkyl epoxides.

[0127] After closing the flow control valve V3 in step (5), the following control continues:

[0128] (a) When 115℃ < reactor internal temperature ≤ T1 (T1 = 125℃), the second TC controller controls the flow control valve V2 to gradually close according to formula (III), where K3 is 9;

[0129] (b) When T2 < reactor internal temperature ≤ 115℃ (T2 = 105℃), the first TC controller controls the flow control valve V1 to gradually close according to formula (IV), in formula (IV), K4 is 10.

[0130] Throughout the entire process, the average temperature difference between the inlet and outlet of the external circulation cooler is 9°C.

[0131] The average number-average molecular weight of the obtained polyether product was 6250, the average molecular weight distribution was 2.85, the molecular weight distribution index deviation between batches of polyether product was ±2.40%, and the reactor utilization rate was 98.80%.

[0132]

Example 4

[0133] Using the system described in Example 1, temperature I was set to 105°C, temperature II to 120°C, the base polyether was a tetrafunctional polyether with a molecular weight of 3000, the catalyst was NaOH, the epoxide was epoxide butane, the amount of base polyether was 14 wt%, the amount of catalyst was 0.19 wt%, and the amount of epoxide was 85.81 wt%. The oxygen content in the reactor was controlled to be less than 150 ppm.

[0134] The method includes:

[0135] (1) Add raw materials including basic polyether and catalyst into the reactor, and heat the materials through the jacket of the reactor until the set temperature I is reached, then turn off the jacket heating.

[0136] (2) Epoxy alkane is introduced into the reactor through the raw material feed pipeline, wherein the flow control valve V3 is gradually opened to 18%, and the opening of the flow control valve V1 is controlled through the electrical connection circuit to control the temperature inside the reactor.

[0137] (3) Continue to gradually increase the opening of the flow control valve V3 to 80% for feeding epoxide alkane. When the opening of the flow control valve V1 reaches 79%, control the opening of the flow control valve V2 through the electrical connection circuit II, thereby controlling the temperature inside the reactor at the set temperature II.

[0138] (4) When the opening degree of flow control valve V2 reaches 95%, the opening degree of flow control valve V3 is controlled through electrical connection circuit three; in step (4), the opening degree of flow control valve V3 is controlled by electrical connection circuit three in the following manner:

[0139] The TC-PC selector receives a pressure signal from the pressure controller: when P1 < internal pressure of the reactor ≤ P2 (P1 = 0.2 MPaG, P2 = 0.4 MPaG), the TC-PC selector receives the pressure signal from the pressure controller and controls the opening of the flow control valve V3 according to formula (I), where K1 is 1 and n1 is 3.

[0140] When 0.0MPaG < reactor internal pressure ≤ P1 (P1 = 0.2MPaG), the TC-PC selector receives the temperature signal from the temperature controller and controls the opening of the flow control valve V3 according to formula (II). In formula (I), K2 is 1 and n2 is 7.

[0141] (5) When the feed rate of alkyl epoxides reaches the set value, the flow control valve V3 is closed via electrical connection loop four to stop the feed. In step (5), the electrical connection loop four performs the following control: when the flow controller FC detects that the feed rate of alkyl epoxides reaches the set value, it controls the flow control valve V3 to close to stop the feed of alkyl epoxides.

[0142] After closing the flow control valve V3 in step (5), the following control continues:

[0143] (a) When 115℃ < reactor internal temperature ≤ T1 (T1 = 128℃), the second TC controller controls the flow control valve V2 to gradually close according to formula (III), in formula (III), K3 is 11;

[0144] (b) When T2 < reactor internal temperature ≤ 115℃ (T2 = 100℃), the first TC controller controls the flow control valve V1 to gradually close according to formula (IV), in formula (IV), K4 is 10.

[0145] Throughout the entire process, the average temperature difference between the inlet and outlet of the external circulation cooler is 7°C.

[0146] The average number-average molecular weight of the obtained polyether product was 6400, the average molecular weight distribution was 2.9, the molecular weight distribution index deviation between batches of polyether product was ±2.43%, and the reactor utilization rate was 99.20%.

[0147]

Example 5

[0148] Using the system described in Example 1, temperature I was set to 110°C, temperature II to 130°C, the base polyether was a difunctional polyether with a molecular weight of 4000, the catalyst was CsOH, the epoxide was epoxide butane, the amount of base polyether was 16 wt%, the amount of catalyst was 0.60 wt%, and the amount of epoxide was 83.4 wt%. The oxygen content in the reactor was controlled to be less than 150 ppm.

[0149] The method includes:

[0150] (1) Add raw materials including basic polyether and catalyst into the reactor, and heat the materials through the jacket of the reactor until the set temperature I is reached, then turn off the jacket heating.

[0151] (2) Epoxy alkane is introduced into the reactor through the raw material feed pipeline, wherein the flow control valve V3 is gradually opened to 11%, and the opening of the flow control valve V1 is controlled through the electrical connection circuit to control the temperature inside the reactor.

[0152] (3) Continue to gradually increase the opening of the flow control valve V3 to 95% to feed the epoxide alkane. When the opening of the flow control valve V1 reaches 71%, the opening of the flow control valve V2 is controlled by the electrical connection circuit II to control the temperature inside the reactor at the set temperature II.

[0153] (4) When the opening degree of flow control valve V2 reaches 65%, the opening degree of flow control valve V3 is controlled through electrical connection circuit three; in step (4), the opening degree of flow control valve V3 is controlled by electrical connection circuit three in the following manner:

[0154] The TC-PC selector receives a pressure signal from the pressure controller: when P1 < internal pressure of the reactor ≤ P2 (P1 = 0.1 MPaG, P2 = 0.35 MPaG), the TC-PC selector receives the pressure signal from the pressure controller and controls the opening of the flow control valve V3 according to formula (I), where K1 is 1 and n1 is 4.

[0155] When 0.0MPaG < reactor internal pressure ≤ P1 (P1 = 0.1MPaG), the TC-PC selector receives the temperature signal from the temperature controller and controls the opening of the flow control valve V3 according to formula (II). In formula (I), K2 is 1 and n2 is 8.

[0156] (5) When the feed rate of alkyl epoxides reaches the set value, the flow control valve V3 is closed via electrical connection loop four to stop the feed. In step (5), the electrical connection loop four performs the following control: when the flow controller FC detects that the feed rate of alkyl epoxides reaches the set value, it controls the flow control valve V3 to close to stop the feed of alkyl epoxides.

[0157] After closing the flow control valve V3 in step (5), the following control continues:

[0158] (a) When 115℃ < reactor internal temperature ≤ T1 (T1 = 117℃), the second TC controller controls the flow control valve V2 to gradually close according to formula (III), where K3 is 12;

[0159] (b) When T2 < reactor internal temperature ≤ 115℃ (T2 = 113℃), the first TC controller controls the flow control valve V1 to gradually close according to formula (IV), in formula (IV), K4 is 12.

[0160] Throughout the entire process, the average temperature difference between the inlet and outlet of the external circulation cooler was 11°C.

[0161] The average number-average molecular weight of the obtained polyether product was 6500, the average molecular weight distribution was 2.95, the molecular weight distribution index deviation between batches of polyether product was ±2.46%, and the reactor utilization rate was 99.5%.

[0162] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A system for batch production of polyether, comprising a reactor, wherein a cooling inner coil, a temperature detector, and a pressure detector are provided inside the reactor; a cooling medium inlet line and a cooling medium outlet line are provided on the cooling inner coil, and a flow control valve V1 is provided on the cooling medium outlet line; a reaction product outlet line is provided at the bottom of the reactor, and a reaction product circulation line is provided between the bottom and top of the reactor or between the bottom and upper part of the reactor.

2. The system according to claim 1, characterized in that, An external circulation cooler is provided on the reaction product circulation pipeline. A cooling medium inlet pipeline and a cooling medium outlet pipeline are provided on the external circulation cooler. A flow control valve V2 is provided on the cooling medium outlet pipeline.

3. The system according to claim 2, characterized in that, The system further includes a first TC controller; wherein the first TC controller is electrically connected to a temperature detector and a flow control valve V1 respectively to form an electrical connection loop one, for controlling the opening degree of the flow control valve V1 by temperature; and / or, The system further includes a second TC controller; wherein the second TC controller is electrically connected to the temperature detector and the flow control valve V2 to form an electrical connection loop two, and is used to control the opening degree of the flow control valve V2 by temperature.

4. The system according to claim 1, characterized in that, A raw material feed line is provided at the top or upper part of the reactor; preferably, a flow control valve V3 is provided on the raw material feed line to control the flow rate of the raw material.

5. The system according to claim 4, characterized in that, The system further includes a TC-PC selection controller, which is electrically connected to the temperature controller, the pressure controller, and the flow control valve V3 to form an electrical connection loop three. Preferably, the TC-PC selection controller receives a pressure signal from the pressure controller and then controls the opening degree of the flow control valve V3 according to the pressure signal: (1) When the pressure inside the reactor is disturbed from the equilibrium state and P1 < the internal pressure P of the reactor, the TC-PC selector controller controls the opening of the flow control valve V3 by the pressure controller; (2) When the pressure inside the reactor is disturbed from the equilibrium state and 0.0MPaG < the internal pressure P of the reactor ≤ P1, the TC-PC selector controller controls the opening of the flow control valve V3 by the temperature controller. Wherein, P1 = 0.1~0.3MPaG.

6. The system according to claim 5, characterized in that, When the pressure inside the reactor is disturbed from its equilibrium state and P1 < the internal pressure P of the reactor, the TC-PC selector receives the pressure change signal from the pressure controller and controls the opening of the flow control valve V3 according to formula (I): Wherein, P0 represents the stable pressure value before the pressure disturbance, V3 opening 0 represents the stable valve V3 opening value before the pressure disturbance, P represents the real-time pressure value inside the vessel after the disturbance, K1 is a constant with a value of 1 to 4, and n1 is a constant with a value of 1 to 4. And / or, When the pressure inside the reactor is disturbed from its equilibrium state and 0.0 MPaG < reactor internal pressure P ≤ P1, the TC-PC selector receives the temperature change signal from the temperature controller and controls the opening of the flow control valve V3 using equation (II): Wherein, V3 opening degree 0 represents the opening degree of valve V3 before pressure disturbance, T0 represents the stable temperature value before temperature change, T represents the real-time temperature value inside the vessel after temperature change, K2 is a constant with a value of 1 to 4, and n2 is a constant with a value of 5 to 8.

7. The system according to any one of claims 1 to 6, characterized in that, A flow controller FC is further provided on the raw material feed pipeline to detect the feed amount of the raw material; preferably, the flow controller FC is electrically connected to the flow control valve V3 to form an electrical connection loop four, wherein when the flow controller FC detects that the feed amount of the raw material reaches the set value, it controls the flow control valve V3 to close.

8. A method for batch production of polyether, carried out using the system described in any one of claims 1 to 7, the method comprising: (1) Add raw materials, including basic polyether and catalyst, into the reactor and heat to the set temperature I; (2) Epoxy alkane is introduced into the reactor through the raw material feed pipeline. The flow control valve V3 is gradually opened to 10% ≤ V3 ≤ 40%. At the same time, the flow control valve V1 is controlled through the electrical connection circuit to control the temperature in the reactor at the set temperature II. (3) Continue to gradually increase the opening of the flow control valve V3 to 40% < V3 ≤ 100% for feeding epoxide alkane. When the opening of the flow control valve V1 reaches 70% to 100%, control the opening of the flow control valve V2 through the electrical connection circuit II to control the temperature inside the reactor at the set temperature II. (4) When the opening degree of flow control valve V2 reaches 60-100%, the opening degree of flow control valve V3 is controlled by electrical connection circuit three. (5) When the feed rate of epoxide alkane reaches the set value, the flow control valve V3 is closed by controlling the circuit four via electrical connection.

9. The method according to claim 8, characterized in that, Prior to step (1), the oxygen content in the reactor is controlled to be less than 150 ppm; and / or, The set temperature I in step (1) is 90–110°C, preferably 95–110°C; and / or, In step (2), the set temperature II is 100-135°C, preferably 100-130°C.

10. The method according to claim 8, characterized in that, In step (2), the following control is performed through the electrical connection circuit: the first TC controller controls the opening of the flow control valve V1 according to the temperature inside the reactor, so as to control the temperature inside the reactor at the set temperature II; And / or, In step (3), the following control is performed through the electrical connection circuit 2: the second TC controller controls the opening of the flow control valve V2 according to the temperature inside the reactor, so as to control the temperature inside the reactor at the set temperature II.

11. The method according to any one of claims 8 to 10, characterized in that, In step (4), the electrical connection loop three controls the opening of the flow control valve V3 in the following manner: the TC-PC selector receives the pressure signal sent from the pressure controller, and then controls the opening of the flow control valve V3 according to the pressure signal: (1) when the pressure inside the reactor is disturbed from the equilibrium state and P1 < the internal pressure P of the reactor, the TC-PC selector controls the pressure controller to control the opening of the flow control valve V3; (2) when the pressure inside the reactor is disturbed from the equilibrium state and 0.0MPaG < the internal pressure P of the reactor ≤ P1, the TC-PC selector controls the temperature controller to control the opening of the flow control valve V3; wherein, P1 = 0.1~0.3MPaG.

12. The method according to claim 11, characterized in that, In step (5), the electrical connection circuit four is controlled as follows: when the flow controller FC detects that the feed amount of epoxy alkane reaches the set value, it controls the flow control valve V3 to close and stops the feed of epoxy alkane; Preferably, in step (5), after closing the flow control valve V3, the flow control valve V2 and the flow control valve V1 are closed sequentially and gradually. More preferably, in step (5), after closing the flow control valve V3, the following control continues: (a) When 115℃ < reactor internal temperature ≤ T1 (preferably T1 = 117℃ ~ 130℃), the second TC controller controls the flow control valve V2 to gradually close through the electrical connection loop two; (b) When T2 < reactor internal temperature ≤ 115℃ (preferably T2 = 100℃ ~ 113℃), the first TC controller gradually closes the flow control valve V1 through the electrical connection loop.

13. A polyether obtained using the system of any one of claims 1 to 7 or the method of any one of claims 8 to 12.

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