Catalyst supply system and supply method for ethylene-propylene rubber production

Abstract

The application belongs to the technical field of ethylene-propylene rubber polymerization catalyst feeding, and particularly relates to a catalyst feeding system and method for ethylene-propylene rubber production. The system comprises a first catalyst unloading tank, wherein the first catalyst unloading tank is only communicated with an inlet of a first metering pump, and an outlet of the first metering pump is only communicated with a catalyst inlet of a polymerization reactor; and a second catalyst unloading tank, wherein the second catalyst unloading tank is only communicated with an inlet of a second metering pump, and an outlet of the second metering pump is only communicated with the catalyst inlet of the polymerization reactor. The system divides "one common pipeline" into "two independent channels which never meet".

Description

Technical Field

[0001] This application belongs to the field of catalyst supply technology for ethylene propylene rubber polymerization, and particularly relates to catalyst supply systems and methods for ethylene propylene rubber production. Background Technology

[0002] The industrial production of ethylene propylene rubber commonly employs solution polymerization, using hexane as a solvent, and copolymerization is carried out under a Ziegler-Natta vanadium-aluminum catalytic system. Traditional equipment uses only one catalyst delivery pipeline; the VX-catalyst generated from the reaction of vanadium oxychloride (V-catalyst) with alcohols must share the same tank, metering pump, and pipeline. When switching product grades, repeated flushing and replacement are necessary; otherwise, residual catalyst entering the reactor will cause the molecular chain structure to deviate from the design value, generating a large amount of "transition material." This material, due to non-compliance with Mooney viscosity, ethylene / propylene ratio, or third monomer content, must be downgraded and sold, with a loss rate reaching 15%–30% of the switching batch. Furthermore, the trace cross-contamination from the shared system amplifies batch-to-batch differences, causing the product consistency index CpK value to drop from 1.67 to below 1.1, leading to increased customer complaints in downstream high-end sealing and automotive parts sectors. Existing technologies reduce the probability of contamination by extending flushing time and increasing solvent consumption, but this increases auxiliary costs per batch by more than 8% and cannot completely eliminate structural differences. Summary of the Invention

[0003] This application provides a catalyst supply system and method for the production of ethylene propylene rubber to solve the following technical problem: how to achieve instant switching between V-catalyst and VX-catalyst with zero cross-contamination without rinsing.

[0004] In a first aspect, embodiments of this application provide a catalyst supply system for the production of ethylene propylene rubber, comprising: The first catalyst unloading tank is connected only to the inlet of the first metering pump, and the outlet of the first metering pump is connected only to the catalyst inlet of the polymerization reactor. The second catalyst unloading tank is connected only to the inlet of the second metering pump, and the outlet of the second metering pump is connected only to the catalyst inlet of the polymerization reactor. There are no shared pipelines, shared pumps, or shared tanks between the first catalyst unloading tank and the second catalyst unloading tank; The first catalyst unloading tank is used to receive and temporarily store vanadium oxychloride liquid catalyst; The second catalyst unloading tank is used to receive the vanadium oxychloride liquid catalyst and to complete the in-situ reaction of vanadium oxychloride with alcohols to generate VX catalyst within the second catalyst unloading tank; The first metering pump is used to quantitatively deliver the vanadium oxychloride liquid catalyst temporarily stored in the first catalyst unloading tank to the polymerization reactor; The second metering pump is used to quantitatively deliver the VX catalyst generated in the second catalyst unloading tank to the polymerization reactor.

[0005] Optionally, the first catalyst unloading tank and the second catalyst unloading tank are each independently equipped with a nitrogen pressurization pipeline. The nitrogen pressurization pipeline is used to apply a constant pressure of 0.03 MPaG to 0.08 MPaG to the corresponding tank to maintain the flow dynamics of the catalyst or VX catalyst.

[0006] Optionally, the first catalyst unloading tank and the second catalyst unloading tank are each independently equipped with an ethylene glycol aqueous solution cooling coil, which is used to maintain the temperature inside the corresponding tank at 5 ℃ to 20 ℃.

[0007] Optionally, the effective volume of the first catalyst unloading tank and the second catalyst unloading tank are each independently set to 1 m3 to 5 m3. The effective volume is used to receive 1 to 5 standard catalyst containers of vanadium oxychloride liquid catalyst at one time, and each standard catalyst container holds 0.8 t to 1.2 t of vanadium oxychloride liquid catalyst.

[0008] Secondly, embodiments of this application provide a method for switching the supply of ethylene propylene rubber catalyst, the method comprising: Upon receiving the instruction to produce the first grade of ethylene propylene rubber, the first vanadium trichloride liquid catalyst is unloaded into the first catalyst unloading tank, and the first vanadium trichloride liquid catalyst is prohibited from entering the second catalyst unloading tank. The first vanadium trichloride liquid catalyst is delivered to the polymerization reactor at a constant flow rate through the first metering pump until the production of the first grade of ethylene propylene rubber is completed. Upon receiving the instruction to produce the second grade of ethylene propylene rubber, the second vanadium trichloride liquid catalyst is unloaded into the second catalyst unloading tank, and anhydrous ethanol is added to the second catalyst unloading tank to allow the vanadium trichloride in the second vanadium trichloride liquid catalyst to react in situ with the anhydrous ethanol to generate the VX catalyst. The VX catalyst is delivered to the polymerization reactor at a constant flow rate via a second metering pump until the production of the second grade ethylene propylene rubber is completed. Throughout the entire process described above, the first catalyst unloading tank and the second catalyst unloading tank remain physically isolated.

[0009] Optionally, the unloading operation is carried out under nitrogen pressurization, wherein the nitrogen pressurization controls the absolute pressure inside the corresponding tank to be between 0.03 MPaG and 0.08 MPaG.

[0010] Optionally, the unloading operation is carried out within a temperature range of 5 ℃ to 20 ℃, and the temperature range is achieved by using an ethylene glycol aqueous solution cooling coil.

[0011] Optionally, each constant flow rate is independently set to 5 kg / h to 50 kg / h, and the constant flow rate is achieved by adjusting the stroke and frequency of the corresponding metering pump.

[0012] Optionally, the molar ratio of anhydrous ethanol to vanadium trichloride is 1:1 to 3:1, and the molar ratio is controlled by a metering valve for adding anhydrous ethanol.

[0013] Optionally, after stopping the first metering pump, the pipeline from the first metering pump to the polymerization reactor is isolated and flushed using hexane solvent. The flushing liquid is directly discharged to the waste liquid system and does not enter the second catalyst unloading tank, the second metering pump, or their downstream pipelines.

[0014] The technical solutions provided in this application have the following advantages compared with the prior art: This application provides a catalyst supply system for ethylene propylene rubber production, which splits a single shared pipeline into two independent channels that never intersect. Vanadium oxychloride (V-catalyst) and VX-catalyst each have their own dedicated unloading tank, metering pump, and outlet pipeline. There are no shared volumes, valves, or pumps between the three, and they are physically isolated. During switching, only one channel needs to be stopped and the other started. Residual liquid from the previous channel is sealed within its own pipeline and cannot cross the vacuum barrier to enter the other channel, thus achieving instantaneous switching within seconds with zero cross-contamination without the need for flushing. Simultaneously, the VX catalyst is prepared in situ within the tank in a single step, avoiding the residual risks associated with repeated transport. Attached Figure Description

[0015] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0017] Figure 1 This is a schematic diagram of a catalyst supply system for the production of ethylene propylene rubber according to an embodiment of this application; in the figure: 1. Second catalyst unloading tank; 2. First catalyst unloading tank; 3. Second metering pump; 4. First metering pump. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] The range descriptions used herein, such as numerical ranges and proportional ranges, include all possible sub-ranges and single numerical values ​​within that range. For example, the range descriptions of "1 to 6" or "1~6" cover all sub-ranges (such as 1 to 3, 2 to 5, etc.) and single numbers (such as 1, 2, 3, 4, 5, 6) between 1 and 6. Unless otherwise specified, the terms "including" and "contains" as used herein mean "including but not limited to"; relational terms such as "first" and "second" are used only to distinguish different entities or operations and do not imply an actual order or relationship; "and / or" indicates that multiple situations can exist individually or simultaneously; expressions such as "at least one," "multiple," and "at least one" refer to any combination of the corresponding objects, including combinations of single or multiple objects. The proportional relationships mentioned herein, such as mass ratios and molar ratios, should be understood as the correspondence between the first and second terms of a proportional formula, according to the order of description. The raw materials, reagents, instruments, and equipment used herein can all be obtained through commercial purchase or prepared using existing methods.

[0020] Figure 1 This is a schematic diagram of a catalyst supply system for the production of ethylene propylene rubber according to an embodiment of this application. Please refer to [link / reference]. Figure 1 : In a first aspect, embodiments of this application provide a catalyst supply system for the production of ethylene propylene rubber, comprising: The first catalyst unloading tank 2 is connected only to the inlet of the first metering pump 4, and the outlet of the first metering pump 4 is connected only to the catalyst inlet of the polymerization reactor. The second catalyst unloading tank 1 is connected only to the inlet of the second metering pump 3, and the outlet of the second metering pump 3 is connected only to the catalyst inlet of the polymerization reactor. There are no shared pipelines, shared pumps, or shared tanks between the first catalyst unloading tank 2 and the second catalyst unloading tank 1; The first catalyst unloading tank 2 is used to receive and temporarily store vanadium oxychloride liquid catalyst; The second catalyst unloading tank 1 is used to receive the vanadium oxychloride liquid catalyst and to complete the in-situ reaction of vanadium oxychloride with alcohols in the second catalyst unloading tank 1 to generate VX catalyst; The first metering pump 4 is used to quantitatively deliver the vanadium trichloride liquid catalyst temporarily stored in the first catalyst unloading tank 2 to the polymerization reactor; The second metering pump 3 is used to quantitatively deliver the VX catalyst generated in the second catalyst unloading tank 1 to the polymerization reactor.

[0021] The first catalyst unloading tank 2 is only connected to the inlet of the first metering pump 4, and the outlet of the first metering pump 4 is only connected to the catalyst inlet of the polymerization reactor. Thus, after the vanadium oxychloride liquid catalyst flows out of the first catalyst unloading tank 2, it can only flow through the first metering pump 4 and the catalyst inlet of the polymerization reactor in sequence, thereby completely eliminating any possibility of the vanadium oxychloride liquid catalyst flowing into the second catalyst unloading tank 1, the second metering pump 3, or the outlet pipeline of the second metering pump 3. The second catalyst unloading tank 1 is only connected to the inlet of the second metering pump 3, and the outlet of the second metering pump 3 is only connected to the catalyst inlet of the polymerization reactor. Thus, after the VX catalyst flows out of the second catalyst unloading tank 1, it can only flow through the second metering pump 3 and the catalyst inlet of the polymerization reactor in sequence, thereby completely eliminating any possibility of the VX catalyst flowing into the first catalyst unloading tank 2, the first metering pump 4, or the outlet pipeline of the first metering pump 4. There are no shared pipelines, shared pumps or shared tanks between the first catalyst unloading tank 2 and the second catalyst unloading tank 1, so that the vanadium oxychloride liquid catalyst and the VX catalyst do not have any form of overlapping volume in the entire flow path, thereby completely eliminating the residual mixing of the two catalysts caused by shared elements. The first catalyst unloading tank 2 is used to receive and temporarily store vanadium oxychloride liquid catalyst, so that when it is necessary to switch to V-catalyst grade, the vanadium oxychloride liquid catalyst can be immediately delivered by the first metering pump 4, thereby realizing the independent readiness of the V-catalyst supply path; The second catalyst unloading tank 1 is used to receive the liquid vanadium oxychloride catalyst and complete the in-situ reaction of vanadium oxychloride with alcohols in the second catalyst unloading tank 1 to generate VX catalyst. Thus, the preparation and storage of VX catalyst are completed in the same closed tank, thereby preventing VX catalyst from entering other pipelines during the transfer process. The first metering pump 4 is used to quantitatively transport the vanadium trichloride liquid catalyst temporarily stored in the first catalyst unloading tank 2 to the polymerization reactor. Thus, only the first metering pump 4 is used in the V-catalyst grade production stage, and there is no need to start the second metering pump 3 and its pipeline. The second metering pump 3 is used to quantitatively transport the VX catalyst generated in the second catalyst unloading tank 1 to the polymerization reactor. Thus, only the second metering pump 3 is used in the VX-catalyst grade production stage, and the first metering pump 4 and its pipeline are not required to be started at all. All of the above features work together to ensure that the two catalysts are absolutely isolated in terms of physical space, flow path and power element, so that either path can be started or stopped instantly without any flushing, thereby achieving instant switching between V-catalyst and VX-catalyst with zero cross-contamination.

[0022] In some embodiments, the first catalyst unloading tank 2 and the second catalyst unloading tank 1 are each independently equipped with a nitrogen pressurization line, which is used to apply a constant pressure of 0.03 MPaG to 0.08 MPaG to the corresponding tank to maintain the flow kinetics of the catalyst or VX catalyst.

[0023] The first catalyst unloading tank 2 is independently equipped with a nitrogen pressurization pipeline, and the second catalyst unloading tank 1 is independently equipped with a nitrogen pressurization pipeline. The two nitrogen pressurization pipelines apply any one of the constant pressures of 0.03 MPaG, 0.04 MPaG, 0.05 MPaG, 0.06 MPaG, 0.07 MPaG, and 0.08 MPaG to the first catalyst unloading tank 2 and the second catalyst unloading tank 1, respectively. In this way, both catalysts obtain flow power by relying on their own independent nitrogen pressure sources, thereby eliminating the risk of pressure fluctuations or reverse crossflow caused by sharing a nitrogen source, and further ensuring that the two catalysts will not cause backflow or residual mixing due to pressure imbalance at the moment of switching.

[0024] In some embodiments, the first catalyst unloading tank 2 and the second catalyst unloading tank 1 are each independently equipped with an ethylene glycol aqueous solution cooling coil, which is used to maintain the temperature inside the corresponding tank at 5 ℃ to 20 ℃.

[0025] The first catalyst unloading tank 2 is independently equipped with an ethylene glycol aqueous solution cooling coil, and the second catalyst unloading tank 1 is also independently equipped with an ethylene glycol aqueous solution cooling coil. The two cooling coils maintain the temperature in the first catalyst unloading tank 2 and the second catalyst unloading tank 1 at any one of the following temperatures: 5 ℃, 6 ℃, 7 ℃, 8 ℃, 9 ℃, 10 ℃, 11 ℃, 12 ℃, 13 ℃, 14 ℃, 15 ℃, 16 ℃, 17 ℃, 18 ℃, 19 ℃, and 20 ℃. This ensures that the active components of both the vanadium oxychloride liquid catalyst and the VX catalyst are preserved at a constant low temperature, thereby avoiding self-decomposition or side reactions caused by temperature rise. Furthermore, it ensures that the properties of the two catalysts are stable in their respective tanks and that no deterioration or cross-contamination will occur before switching.

[0026] In some embodiments, the effective volume of the first catalyst unloading tank 2 and the second catalyst unloading tank 1 is independently set to 1 m3 to 5 m3. The effective volume is used to receive 1 to 5 standard catalyst containers of vanadium oxychloride liquid catalyst at one time, and each standard catalyst container holds 0.8 t to 1.2 t of vanadium oxychloride liquid catalyst.

[0027] The effective volume of the first catalyst unloading tank 2 is independently set to 1 m³. 3 The effective volume of the second catalyst unloading tank 1 is independently set to 1 m³, which can be any of the following volumes: 1.5 m³, 2 m³, 2.5 m³, 3 m³, 3.5 m³, 4 m³, 4.5 m³, or 5 m³. 3 It can accommodate any volume of 1.5 m3, 2 m3, 2.5 m3, 3 m3, 3.5 m3, 4 m3, 4.5 m3, or 5 m3, allowing each tank to receive any number of standard catalyst containers at a time, ranging from 1 to 5. Each standard catalyst container can hold any mass of vanadium oxychloride liquid catalyst, ranging from 0.8 t, 0.9 t, 1.0 t, 1.1 t, or 1.2 t. This extends the continuous catalyst supply time of a single tank to several hours to tens of hours, further reducing the switching frequency and lowering the residual risk caused by frequent start-ups and shutdowns. As a result, it can maintain long-term zero-cross-contamination operation without flushing.

[0028] Secondly, embodiments of this application provide a method for switching the supply of ethylene propylene rubber catalyst, the method comprising: Upon receiving the instruction to produce the first grade of ethylene propylene rubber, the first vanadium trichloride liquid catalyst is unloaded into the first catalyst unloading tank 2, and the first vanadium trichloride liquid catalyst is prohibited from entering the second catalyst unloading tank 1. The first vanadium oxychloride liquid catalyst is delivered to the polymerization reactor at a constant flow rate through the first metering pump 4 until the production of the first grade of ethylene propylene rubber is completed. Upon receiving the instruction to produce the second grade of ethylene propylene rubber, the second vanadium trichloride liquid catalyst is unloaded into the second catalyst unloading tank 1, and anhydrous ethanol is added to the second catalyst unloading tank 1 to allow the vanadium trichloride in the second vanadium trichloride liquid catalyst to react in situ with the anhydrous ethanol to generate the VX catalyst. The VX catalyst is delivered to the polymerization reactor at a constant flow rate via the second metering pump 3 until the production of the second grade ethylene propylene rubber is completed. Throughout the entire process described above, the first catalyst unloading tank 2 and the second catalyst unloading tank 1 are physically isolated from each other.

[0029] Upon receiving the instruction to produce the first grade of ethylene propylene rubber, the first vanadium trichloride liquid catalyst is unloaded into the first catalyst unloading tank 2, and the first vanadium trichloride liquid catalyst is prohibited from entering the second catalyst unloading tank 1, thus the V-catalyst path is uniquely determined at the source. The first vanadium trichloride liquid catalyst is delivered to the polymerization reactor at a constant flow rate through the first metering pump 4 until the production of the first grade of ethylene propylene rubber is completed. Thus, the entire production stage only uses the first catalyst unloading tank 2, the first metering pump 4 and its pipeline. Upon receiving the instruction to produce the second grade of ethylene propylene rubber, the second vanadium trichloride liquid catalyst is unloaded into the second catalyst unloading tank 1, and anhydrous ethanol is added to the second catalyst unloading tank 1 to allow the vanadium trichloride in the second vanadium trichloride liquid catalyst to react in situ with the anhydrous ethanol to generate VX catalyst. Thus, the preparation and storage of VX catalyst are completed within the second catalyst unloading tank 1, without the need for external transportation. The VX catalyst is delivered to the polymerization reactor at a constant flow rate through the second metering pump 3 until the production of the second grade of ethylene propylene rubber is completed. Thus, the entire production stage only uses the second catalyst unloading tank 1, the second metering pump 3 and its pipelines. Throughout the entire process, the first catalyst unloading tank 2 and the second catalyst unloading tank 1 are physically isolated, so that the two catalysts do not share a volume or intersect at any time, thereby achieving instant switching without rinsing and zero cross-contamination.

[0030] In some embodiments, the unloading operation is carried out under nitrogen pressurization, which controls the absolute pressure inside the corresponding tank at 0.03 MPaG to 0.08 MPaG.

[0031] All unloading operations are carried out under nitrogen pressurization. Nitrogen pressurization controls the absolute pressure inside the corresponding tank to any one of the following pressures: 0.03 MPaG, 0.04 MPaG, 0.05 MPaG, 0.06 MPaG, 0.07 MPaG, and 0.08 MPaG. This ensures that the two catalysts are sealed by their respective independent positive pressures during the unloading stage, thereby preventing backflow of air or cross-contamination caused by negative pressure or normal pressure. This further ensures the purity of the atmosphere inside the tank at the moment of switching and avoids foreign impurities or cross-residues.

[0032] In some embodiments, the unloading operation is carried out within a temperature range of 5°C to 20°C, which is achieved by using an ethylene glycol aqueous solution cooling coil.

[0033] The unloading operation is carried out within any temperature range of 5 ℃, 6 ℃, 7 ℃, 8 ℃, 9 ℃, 10 ℃, 11 ℃, 12 ℃, 13 ℃, 14 ℃, 15 ℃, 16 ℃, 17 ℃, 18 ℃, 19 ℃, and 20 ℃. The temperature range is achieved by using an ethylene glycol aqueous solution with a cooling coil. This ensures that the reaction rate of the vanadium oxychloride liquid catalyst and anhydrous ethanol is precisely controlled within the low temperature range, thereby avoiding side reactions or overheating decomposition. Furthermore, it ensures the consistency of VX catalyst composition, making the catalyst activity in the reactor instantly stable after switching and eliminating cross-contamination caused by activity differences.

[0034] In some implementations, the constant flow rate is independently set to 5 kg / h to 50 kg / h, and the constant flow rate is achieved by adjusting the stroke and frequency of the corresponding metering pump.

[0035] The constant flow rate is independently set to any one of the following: 5 kg / h, 10 kg / h, 15 kg / h, 20 kg / h, 25 kg / h, 30 kg / h, 35 kg / h, 40 kg / h, 45 kg / h, and 50 kg / h. The constant flow rate is achieved by adjusting the stroke and frequency of the corresponding metering pump. This ensures that both catalysts maintain a laminar steady state during transport, thereby avoiding pipeline residual scouring or backflow caused by flow fluctuations. Furthermore, it ensures that the old catalyst is completely pushed away by the new catalyst at the moment of switching, and zero cross-contamination can be achieved without additional rinsing.

[0036] In some embodiments, the molar ratio of anhydrous ethanol to vanadium trichloride is 1:1 to 3:1, and the molar ratio is controlled by a metering valve for adding anhydrous ethanol.

[0037] The molar ratio of anhydrous ethanol to vanadium oxychloride is any one of 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1, 2:1, 2.2:1, 2.4:1, 2.6:1, 2.8:1, or 3:1. The molar ratio is controlled by a metering valve for adding anhydrous ethanol, thereby precisely locking the chemical composition of the VX catalyst in one step. This avoids byproduct residues caused by excess or insufficient ethanol, and further ensures that the VX catalyst will not carry alcohols or byproducts that could contaminate the next V-catalyst brand after switching into the polymerization reactor, achieving zero cross-contamination without rinsing.

[0038] In some embodiments, after the first metering pump 4 is stopped, the pipeline from the first metering pump 4 to the polymerization reactor is isolated and flushed with hexane solvent. The flushing liquid is directly discharged to the waste liquid system and does not enter the second catalyst unloading tank 1, the second metering pump 3 and their downstream pipelines.

[0039] After stopping the first metering pump 4, hexane solvent is used to isolate and flush the pipeline from the first metering pump 4 to the polymerization reactor. The flushing liquid is directly discharged to the waste liquid system and does not enter the second catalyst unloading tank 1, the second metering pump 3 and their downstream pipelines. Thus, the V-catalyst residue is carried out by the hexane solvent in one go and completely removed from the system, thereby avoiding the subsequent pollution that may be caused by the V-catalyst residue standing in the common outlet section. Since the flushing liquid is forcibly discharged to the waste liquid system and has no connection with the VX catalyst side, the local isolation cleaning of "flushing only the outlet and not the system" is achieved, further ensuring zero cross-contamination without flushing the main system.

[0040] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to industry standards. If there is no corresponding industry standard, then generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0041] I. Implementation Examples Example 1 The method for switching the supply of ethylene propylene rubber catalyst includes the following steps in sequence: a) Upon receiving the instruction to produce the first grade of ethylene propylene rubber, the first vanadium trichloride liquid catalyst is unloaded into the first catalyst unloading tank 2, and the first vanadium trichloride liquid catalyst is prohibited from entering the second catalyst unloading tank 1. b) The first vanadium trichloride liquid catalyst is delivered to the polymerization reactor at a constant flow rate of 5 kg / h via the first metering pump 4 until the production of the first grade of ethylene propylene rubber is completed; c) Upon receiving the instruction to produce the second grade of ethylene propylene rubber, the second vanadium trichloride liquid catalyst is unloaded into the second catalyst unloading tank 1, and anhydrous ethanol is added to the second catalyst unloading tank 1. The molar ratio of anhydrous ethanol to vanadium trichloride is 1:1, so that the vanadium trichloride in the second vanadium trichloride liquid catalyst reacts with anhydrous ethanol in situ to generate VX catalyst. d) The VX catalyst is delivered to the polymerization reactor at a constant flow rate of 5 kg / h via the second metering pump 3 until the production of the second grade ethylene propylene rubber is completed; e) Throughout the entire process described above, the first catalyst unloading tank 2 and the second catalyst unloading tank 1 are physically isolated from each other.

[0042] Example 2 Except for the constant flow rate of 20 kg / h in steps b) and d), the other steps are exactly the same as in Example 1.

[0043] Example 3 Except for the constant flow rate of 50 kg / h in steps b) and d), the other steps are exactly the same as in Example 1.

[0044] Example 4 Except for step c), where the molar ratio of anhydrous ethanol to vanadium trichloride is 2:1, the other steps are exactly the same as in Example 1.

[0045] Example 5 Except for step c), where the molar ratio of anhydrous ethanol to vanadium trichloride is 3:1, the other steps are exactly the same as in Example 1.

[0046] Example 6 Except for the constant flow rate of 30 kg / h in steps b) and d), and the molar ratio of 2:1 in step c), the other steps are exactly the same as in Example 1.

[0047] II. Comparative Example Comparative Example 1 The method for supplying ethylene propylene rubber catalyst includes the following steps in sequence: a) Upon receiving the instruction to produce the first grade of ethylene propylene rubber, the first vanadium trichloride liquid catalyst is unloaded into the shared catalyst unloading tank; b) The first vanadium trichlorooxychloride liquid catalyst is delivered to the polymerization reactor at a constant flow rate of 5 kg / h via a shared metering pump until the production of the first grade of ethylene propylene rubber is completed; c) Flush the shared catalyst unloading tank, shared metering pump and shared pipeline with hexane, and discharge the flushing solution into the waste liquid system; d) Upon receiving the instruction to produce the second grade of ethylene propylene rubber, the second vanadium trichloride liquid catalyst is unloaded into the same common catalyst unloading tank, and anhydrous ethanol is added. The molar ratio of anhydrous ethanol to vanadium trichloride is 1:1, so that the vanadium trichloride in the second vanadium trichloride liquid catalyst reacts with anhydrous ethanol to generate VX catalyst. e) The VX catalyst is delivered to the polymerization reactor at a constant flow rate of 5 kg / h using the same common metering pump until the production of the second grade ethylene propylene rubber is completed.

[0048] Comparative Example 2 Except for the constant flow rate of 20 kg / h in steps b) and d), the other steps are exactly the same as those in Comparative Example 1.

[0049] Comparative Example 3 Except for the constant flow rate of 50 kg / h in steps b) and d), the other steps are exactly the same as those in Comparative Example 1.

[0050] III. Results Data Experimental methods for evaluating results: Switching time: Records the time required from the stop of the first brand of metering pump to the start of the second brand of metering pump and the achievement of the set flow rate, using a stopwatch and converted to minutes.

[0051] Transition material quantity: Collect all materials from the outlet of the polymerization reactor after the switchover, where the Mooney viscosity at three consecutive points is within the target value ±1 mL, and weigh and record the weight.

[0052] Vanadium residue: The vanadium concentration was determined by ICP-OES in the first product sample after switching and converted to ppm.

[0053] Alcohol residue: The ethanol concentration in the first product sample after switching was determined by gas chromatography and converted to ppm.

[0054] Mooney viscosity fluctuation ΔML: Take 10 batches of samples consecutively, determine the Mooney viscosity according to GB / T 1232, and calculate the difference between the maximum and minimum values.

[0055] Batch pass rate: The percentage of batches that meet the target specifications in terms of Mooney viscosity, ethylene content, and third monomer content out of 30 consecutive batches.

[0056] Table 1. Results data for both the examples and comparative examples.

[0057] As shown in Table 1, the technological advancements of this application's technical solution include: 1. The switching time is reduced from a minimum of 35 minutes in the comparative example to 0 minutes in the example, thereby completely eliminating the downtime caused by flushing / displacement, and thus realizing the instantaneous switching between V-catalyst and VX-catalyst.

[0058] 2. The amount of transition material is reduced from a minimum of 175 kg in the comparative example to 0 kg in the example, thereby completely avoiding the generation of unqualified "transition material" or "substandard product", and thus directly eliminating the material downgrade loss caused by grade switching.

[0059] 3. Vanadium residue was reduced from a minimum of 18 ppm in the comparative example to <1 ppm in the example, thereby reducing metal contamination of the first grade catalyst in the subsequent grade product by more than an order of magnitude, thus meeting the stringent requirement of ≤5 ppm for catalyst impurities in high-end ethylene propylene rubber.

[0060] 4. The alcohol residue was reduced from a minimum of 12 ppm in the comparative example to <1 ppm in the example, thereby completely eliminating the risk of alcohol byproducts remaining in subsequent V-catalyst grades, and thus avoiding polymerization activity drift and product performance fluctuations caused by alcohol residue.

[0061] 5. The Mooney viscosity fluctuation ΔML was reduced from a minimum of 2.1 ML in the comparative example to a maximum of 0.4 ML in the example, thereby reducing the batch-to-batch Mooney viscosity difference to less than 1 / 5 of the original technology, thus significantly improving product consistency and reducing customer complaint rate.

[0062] 6. The batch pass rate is increased from a maximum of 86% in the comparative example to 100% in the example, thereby achieving zero non-conformities within 30 consecutive batches, which in turn increases the monthly capacity utilization rate of the equipment by ≥14% and completely eliminates economic claims caused by quality deviations.

[0063] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A catalyst supply system for the production of ethylene propylene rubber, characterized in that, include: The first catalyst unloading tank is connected only to the inlet of the first metering pump, and the outlet of the first metering pump is connected only to the catalyst inlet of the polymerization reactor. The second catalyst unloading tank is connected only to the inlet of the second metering pump, and the outlet of the second metering pump is connected only to the catalyst inlet of the polymerization reactor. There are no shared pipelines, shared pumps, or shared tanks between the first catalyst unloading tank and the second catalyst unloading tank; The first catalyst unloading tank is used to receive and temporarily store vanadium oxychloride liquid catalyst; The second catalyst unloading tank is used to receive the vanadium oxychloride liquid catalyst and to complete the in-situ reaction of vanadium oxychloride with alcohols to generate VX catalyst within the second catalyst unloading tank; The first metering pump is used to quantitatively deliver the vanadium oxychloride liquid catalyst temporarily stored in the first catalyst unloading tank to the polymerization reactor; The second metering pump is used to quantitatively deliver the VX catalyst generated in the second catalyst unloading tank to the polymerization reactor.

2. The catalyst supply system according to claim 1, characterized in that, The first catalyst unloading tank and the second catalyst unloading tank are each independently equipped with a nitrogen pressurization pipeline. The nitrogen pressurization pipeline is used to apply a constant pressure of 0.03 MPaG to 0.08 MPaG to the corresponding tank to maintain the flow dynamics of the catalyst or VX catalyst.

3. The catalyst supply system according to claim 1, characterized in that, The first catalyst unloading tank and the second catalyst unloading tank are each independently equipped with an ethylene glycol aqueous solution cooling coil, which is used to maintain the temperature inside the corresponding tank at 5 ℃~20 ℃.

4. The catalyst supply system according to claim 1, characterized in that, The effective volumes of the first catalyst unloading tank and the second catalyst unloading tank are each independently set to 1 m³. 3 ~5 m 3 The effective volume is used to receive 1 to 5 standard catalyst containers of vanadium oxychloride liquid catalyst at one time, and each standard catalyst container holds 0.8 t to 1.2 t of vanadium oxychloride liquid catalyst.

5. A method for switching the supply of ethylene propylene rubber catalyst, characterized in that, The method includes: Upon receiving the instruction to produce the first grade of ethylene propylene rubber, the first vanadium trichloride liquid catalyst is unloaded into the first catalyst unloading tank, and the first vanadium trichloride liquid catalyst is prohibited from entering the second catalyst unloading tank. The first vanadium trichloride liquid catalyst is delivered to the polymerization reactor at a constant flow rate through the first metering pump until the production of the first grade of ethylene propylene rubber is completed. Upon receiving the instruction to produce the second grade of ethylene propylene rubber, the second vanadium trichloride liquid catalyst is unloaded into the second catalyst unloading tank, and anhydrous ethanol is added to the second catalyst unloading tank to allow the vanadium trichloride in the second vanadium trichloride liquid catalyst to react in situ with the anhydrous ethanol to generate the VX catalyst. The VX catalyst is delivered to the polymerization reactor at a constant flow rate via a second metering pump until the production of the second grade ethylene propylene rubber is completed. Throughout the entire process described above, the first catalyst unloading tank and the second catalyst unloading tank remain physically isolated.

6. The method according to claim 5, characterized in that, All unloading operations are carried out under nitrogen pressurization, which controls the absolute pressure inside the corresponding tank at 0.03 MPaG to 0.08 MPaG.

7. The method according to claim 5, characterized in that, The unloading operations are all carried out within a temperature range of 5 ℃ to 20 ℃, which is achieved by using an ethylene glycol aqueous solution cooling coil.

8. The method according to claim 5, characterized in that, The constant flow rates are each independently set to 5 kg / h to 50 kg / h, and the constant flow rates are achieved by adjusting the stroke and frequency of the corresponding metering pump.

9. The method according to claim 5, characterized in that, The molar ratio of anhydrous ethanol to vanadium trichloride is 1:1 to 3:1, and the molar ratio is controlled by a metering valve for adding anhydrous ethanol.

10. The method according to claim 5, characterized in that, After stopping the first metering pump, the pipeline from the first metering pump to the polymerization reactor is isolated and flushed with hexane solvent. The flushing liquid is directly discharged to the waste liquid system and does not enter the second catalyst unloading tank, the second metering pump, or their downstream pipelines.

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