Method for investigating polymerization performance of reactor wall surface chemical treatment agent before application
By evaluating the polymerization performance of a carrier activated at high temperature with a surface chemical treatment agent, the problem of not being able to determine the polymerization performance of chemical treatment agents in existing technologies is solved, ensuring the stability and production efficiency of the reactor.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI LEADER CATALYST
- Filing Date
- 2024-11-04
- Publication Date
- 2026-05-08
AI Technical Summary
Existing technologies cannot effectively determine the polymerization performance of chemical treatment agents on reactor wall surfaces, which may result in products that are qualified at the factory but may perform poorly in application, affecting the performance and stability of the reactor.
The polymerization reaction is carried out by mixing a high-temperature activated carrier with a surface chemical treatment agent. The ratio of polyethylene powder to chemical treatment agent is calculated to determine its polymerization performance and ensure that it can successfully generate polyethylene during application.
Effectively assess the polymerization performance of surface chemical treatment agents to avoid problems where the product is qualified at the factory but performs poorly during application, thus ensuring the stability and production efficiency of the reactor.
Smart Images
Figure CN121994634A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of chemical engineering technology, and specifically to a method for examining the polymerization performance of a chemical treatment agent for reactor wall surface before application. Background Technology
[0002] Before start-up, reactor walls in gas-phase polyethylene (GPE) plants like Univation require chemical treatment. The working principle of surface chemical treatment agents is to deposit specific chromium ions onto the reactor walls, effectively reducing the sensitivity to static electricity generated on the inner walls of the GPE reactor system. This treatment is crucial for ensuring the smooth start-up and operation of the GPE plant, as it improves reactor performance and stability, while also contributing to increased production efficiency and product quality. Furthermore, the use of these surface chemical treatment agents can extend the reactor's lifespan to some extent, reducing the frequency of maintenance and repairs, thereby lowering overall operating costs.
[0003] One criterion for judging the performance of surface chemical treatment agents is their ability to form a polyethylene film on the reactor wall after ethylene is introduced into the reactor. Current technologies often analyze the appearance and composition of surface chemical treatment agents to determine if they meet certain technical specifications. However, this cannot assess the polymerization performance of the surface chemical treatment agent before application. The active ingredients of surface chemical treatment agents are sensitive to impurities such as water and oxygen. The presence of these impurities significantly affects their performance, i.e., their polymerization performance, resulting in insufficient activity during the treatment reaction. This can easily lead to situations where the surface chemical treatment agent is "qualified at the factory but unusable in application." Summary of the Invention
[0004] To avoid situations where surface chemical treatment agents are "qualified at the factory but fail to work properly in application," this invention provides a method for examining the polymerization performance of surface chemical treatment agents for reactor walls before application.
[0005] The objective of this invention can be achieved through the following technical solutions:
[0006] A method for evaluating the polymerization performance of a reactor wall surface chemical treatment agent before application, comprising the following steps:
[0007] S1. The carrier is activated at high temperature to obtain a high-temperature activated carrier;
[0008] S2. Mix the high-temperature activated carrier, solvent and surface chemical treatment agent evenly, recover the solvent, and cool with liquid nitrogen and hydrazine to obtain the surface chemical treatment agent to be evaluated after loading.
[0009] S3. Add the loaded surface chemical treatment agent, co-catalyst and solvent to the reactor, introduce ethylene to carry out the polymerization reaction, and separate the polyethylene powder.
[0010] S4. After drying the polyethylene powder, weigh it and calculate the ratio of the polyethylene powder weight (g) to the amount of surface chemical treatment agent to be evaluated after loading (g). When the ratio is greater than or equal to 10, preferably 10-125, it is determined that the activity of the surface chemical treatment agent has not been affected, and it is speculated that the surface chemical treatment agent can be successfully polymerized to produce polyethylene when applied, which meets the application requirements. According to industrial application experience, considering that polyethylene cannot completely cover the reactor surface in actual application, it is required that the amount of polyethylene polymerized and bonded to the reactor surface after surface treatment is between 10-125 times that of the surface chemical treatment agent to meet the requirements.
[0011] The surface chemical treatment agent contains chromium, and the co-catalyst contains aluminum, with an aluminum-chromium ratio of 0.01-60, preferably 10-60.
[0012] Further, in S1, the high-temperature activation step of the carrier specifically involves: gradually increasing the temperature from room temperature to 200-250℃ for 0.5-1 h, and holding at 200-250℃ for 0.5-3 h; then gradually increasing the temperature again to 500-600℃ for 1-1.5 h, and holding at 500-600℃ for 3-4 h; and finally gradually cooling down to room temperature for 2-4 h.
[0013] Key components of surface chemical treatment agents are sensitive to water and oxygen. Amorphous silica gel absorbs moisture during production and transportation and contains a large number of hydroxyl groups, all of which affect the surface chemical treatment agent. Therefore, amorphous silica gel needs to be treated. Because the amorphous silica gel used has a certain porous structure, it needs to undergo high-temperature activation treatment under a specific procedure, as shown below:
[0014] The temperature is gradually increased from room temperature to 200℃, taking 1 hour to heat and then held at 200℃ for 1 hour; then gradually increased to 600℃, taking 1.5 hours to heat and then held at 600℃ for 3 hours; finally, the temperature is gradually decreased to room temperature, taking 2 hours to decrease.
[0015] Nitrogen protection is required during cooling, and the sample is collected in a sealed container under nitrogen protection for future use.
[0016] Furthermore, in S1, the carrier is macroporous amorphous silica gel with a specific surface area ≥200m². 2 / g.
[0017] Furthermore, the specific surface area of the macroporous amorphous silicone is 200-600 m². 2 / g (preferably 300-450mg) 2A silica carrier with a pore volume of 1.0-3.8 ml / g (preferably 2.5-3.2 ml / g) and a pore size of 25-100 μm (preferably 35-60 μm).
[0018] Furthermore, the ratio of the high-temperature activated carrier, solvent, and surface chemical treatment agent is 10g:80ml:1.6g.
[0019] Further, in S2, the solvent is one or more selected from pentane, n-hexane, cyclohexane, n-heptane, and toluene. Specifically, the solvent is a long-chain saturated aliphatic hydrocarbon and toluene, and is not limited to pentane, n-hexane, cyclohexane, or n-heptane.
[0020] Furthermore, in S2, the particle size of the catalyst is 25-100 μm, preferably 35-60 μm.
[0021] Furthermore, in S2, the mixing temperature is 20-55℃ and the processing time is 1-6h.
[0022] Further, in S3, the co-catalyst is alkylaluminum. Preferably, in S3, the co-catalyst is triethylaluminum or triisobutylaluminum.
[0023] Further, S3 specifically involves: heating the reactor to 60-70°C and evacuating it, then replacing the air inside the reactor with nitrogen; adding the loaded surface chemical treatment agent to be evaluated, the co-catalyst, and hexane, and then introducing ethylene to replace the nitrogen; continuously introducing ethylene, raising the temperature to 75-85°C, reacting for 2 hours, and stirring at a speed of 350-550 rpm, preferably 450 rpm. The molar ratio of aluminum content in the co-catalyst to chromium content in the loaded surface chemical treatment agent to be evaluated is 10-60.
[0024] This invention provides a method for evaluating the polymerization performance of surface treatment agents before their application on reactor walls, thus avoiding situations where surface chemical treatment agents are "qualified at the factory but unusable during application". Attached Figure Description
[0025] Figure 1 This is a schematic diagram of the reaction vessel in this invention;
[0026] Figure 2 This is a schematic diagram of the carrier processing temperature control of the present invention;
[0027] Figure 3 This is an SEM image of the carrier in Example 1 (magnification: 500x). Detailed Implementation
[0028] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.
[0029] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. Unless otherwise specified, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.
[0030] The endpoints and any values of the ranges disclosed in this invention are not limited to the precise ranges or values, and 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 in this invention.
[0031] In this embodiment, the chromium content was tested using inductively coupled plasma (ICP) method.
[0032] Example 1
[0033] The carrier silicone was commercially available 955 silicone, and its SEM results are shown in [link to SEM image]. Figure 3 ,according to Figure 2 High-temperature activation treatment was performed to obtain a high-temperature activated carrier.
[0034] A catalyst preparation platform was constructed and purged with nitrogen for 3 hours. 10g of a high-temperature activated support and 80ml of pentane were added. The oil bath temperature was set to approximately 35℃, and the reactor temperature was raised to 30℃, with high-speed stirring for 1 hour. 1.6g of the surface chemical treatment agent solution (SLD-CRM-1) was drawn using a syringe, and the actual mass of the surface chemical treatment agent solution added to the reactor was recorded. The reaction was continued at 30℃ with stirring for 1 hour. The solvent-loaded surface chemical treatment agent powder to be evaluated was recovered and named SCRM-1. SCRM-1 was transferred to a siphon flask for later use.
[0035] A 2L stainless steel reactor was heated to 65℃ and evacuated, then purged with purified high-purity nitrogen. 1000mL of purified, dried hexane, 2g of SCRM-1, and triethylaluminum co-catalyst were added. The high-purity nitrogen in the reactor was replaced with ethylene, and stirring was started. Ethylene was continuously added, and the temperature was raised to 80℃. The reaction was carried out at 80℃ for 2 hours. After the polymerization reaction was completed, the ethylene reaction was stopped, and the polyethylene powder was separated from the hexane after cooling. The powder was dried, weighed, and the polymerization activity was calculated. The molar ratio of Al in the triethylaluminum co-catalyst to Cr in SCRM-1 was calculated, with Al / Cr taken as 30. The results are shown in Table 1.
[0036] Example 2
[0037] The carrier silica gel used was commercially available ES70W silica gel. During activation, the 600℃ isothermal phase lasted for 6 hours, and the remaining steps were performed according to... Figure 2 High-temperature activation treatment was performed to obtain a high-temperature activated carrier.
[0038] A catalyst preparation platform was constructed and purged with nitrogen for 3 hours. 10g of silica gel and 80ml of hexane were added. The oil bath was set to approximately 45℃ and stirred at high speed for 3 hours. 1.6g of the surface chemical treatment agent solution (SLD-CRM-2) was drawn up using a syringe, and the actual mass of the surface chemical treatment agent solution added to the reactor was recorded. The solvent was recovered to obtain the loaded surface chemical treatment agent powder to be evaluated, named SCRM-2. SCRM-2 was transferred to a siphon flask for later use.
[0039] A 2L stainless steel reactor was heated to 70℃ and evacuated, then purged with purified high-purity nitrogen. 1200mL of purified, dried hexane, 2.2g of SCRM-2, and the co-catalyst triisobutylaluminum were added. The high-purity nitrogen in the reactor was replaced with ethylene, and stirring was started. Ethylene was continuously added, and the temperature was raised to 78℃. The reaction was carried out at 78℃ for 2 hours. After the polymerization reaction was completed, the ethylene reaction was stopped, and the polyethylene powder was separated from the hexane after cooling. The powder was dried, weighed, and the polymerization activity was calculated. The molar ratio of Al in the co-catalyst triisobutylaluminum to Cr in SCRM-2 was calculated, with Al / Cr taken as 40. The results are shown in Table 1.
[0040] Example 3
[0041] The carrier silicone was commercially available ES757 silicone. During the high-temperature activation process, the temperature was raised from room temperature to a constant 250°C, and the rest was carried out according to... Figure 2 High-temperature activation treatment was performed to obtain a high-temperature activated carrier.
[0042] A catalyst preparation platform was constructed and purged with nitrogen for 3 hours. 10g of silica gel and 80ml of hexane were added. The oil bath was set to approximately 55℃, and the mixture was stirred at high speed for 3 hours. 1.6g of the surface chemical treatment agent solution (SLD-CRM-3) was drawn up using a syringe, and the actual mass of the surface chemical treatment agent solution added to the reactor was recorded. The reaction was continued at 30℃ with stirring for another 3 hours. The solvent was recovered to obtain the loaded surface chemical treatment agent powder to be evaluated, named SCRM-3. SCRM-3 was transferred to a siphon flask for later use.
[0043] A 2L stainless steel reactor was heated to 60℃ and evacuated, then purged with purified high-purity nitrogen. 1200mL of purified, dried hexane, 2.1g of SCRM-3, and triethylaluminum co-catalyst were added. After replacing the high-purity nitrogen in the reactor with ethylene, stirring was started, and ethylene was continuously added while the temperature was raised to 82℃. The reaction was carried out at 82℃ for 2 hours. After the polymerization reaction was completed, ethylene was stopped, and the mixture was cooled before separating the polyethylene powder from the hexane. The powder was dried, weighed, and the polymerization activity was calculated. The molar ratio of Al in the triethylaluminum co-catalyst to Cr in SCRM-3 was calculated, with Al / Cr taken as 30. The results are shown in Table 1.
[0044] Table 1
[0045]
[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.
Claims
1. A method for examining the polymerization performance of a chemical treatment agent for reactor wall surface before application, characterized in that, Includes the following steps: S1. The carrier is activated at high temperature to obtain a high-temperature activated carrier; S2. Mix the high-temperature activated carrier, solvent and surface chemical treatment agent evenly, recover the solvent, and cool with liquid nitrogen and hydrazine to obtain the surface chemical treatment agent to be evaluated after loading. S3. Add the loaded surface chemical treatment agent, co-catalyst and solvent to the reactor, introduce ethylene to carry out the polymerization reaction, and separate the polyethylene powder. S4. After drying the polyethylene powder, weigh it and calculate the ratio of the weight of the polyethylene powder (g) to the amount of surface chemical treatment agent to be evaluated after loading (g). When the ratio is >10, it is determined that the surface chemical treatment agent meets the application requirements. The surface chemical treatment agent contains chromium, and the co-catalyst contains aluminum, with an aluminum-chromium ratio of 0.01-60.
2. The method for examining the polymerization performance of a reactor wall surface chemical treatment agent before application, as described in claim 1, is characterized in that... In S1, the high-temperature activation step of the carrier is specifically as follows: the temperature is gradually increased from room temperature to 200-250℃ for 0.5-1h, and then held at 200-250℃ for 0.5-3h; the temperature is then gradually increased again to 500-600℃ for 1-1.5h, and then held at 500-600℃ for 3-4h; finally, the temperature is gradually decreased to room temperature for 2-4h.
3. The method for examining the polymerization performance of a reactor wall surface chemical treatment agent before application, as described in claim 1, is characterized in that... In S1, the carrier is macroporous amorphous silica gel with a specific surface area ≥200m². 2 / g.
4. The method for examining the polymerization performance of a reactor wall surface chemical treatment agent before application, as described in claim 3, is characterized in that... The specific surface area of the macroporous amorphous silica gel is 200-600 m². 2 / g, pore volume is 1.0-3.8ml / g, pore size is 25-100μm.
5. In the method for examining the polymerization performance of a reactor wall surface chemical treatment agent before application according to claim 1, in S2, the ratio of the high-temperature activated carrier, hexane, and surface chemical treatment agent is 10g:80ml:1.6g.
6. The method for examining the polymerization performance of a reactor wall surface chemical treatment agent before application according to claim 1, wherein in S2, the solvent is one or more of pentane, n-hexane, cyclohexane, n-heptane, and toluene.
7. In the method for examining the polymerization performance of a reactor wall surface chemical treatment agent before application according to claim 1, in S2, the particle size of the catalyst is 25-100 μm.
8. The method for examining the polymerization performance of a reactor wall surface chemical treatment agent before application, as described in claim 1, is characterized in that... In S3, the co-catalyst is alkylaluminum.
9. The method for examining the polymerization performance of a reactor wall surface chemical treatment agent before application, as described in claim 1, is characterized in that... In S3, the co-catalyst is triethylaluminum or triisobutylaluminum.
10. The method for examining the polymerization performance of a reactor wall surface chemical treatment agent before application, as described in claim 1, is characterized in that... S3 specifically involves: heating the reactor to 60-70℃ and evacuating it, replacing the air in the reactor with nitrogen; adding the loaded surface chemical treatment agent to be evaluated, the co-catalyst, and hexane, and then introducing ethylene to replace the nitrogen. Continuously introduce ethylene, raise the temperature to 75-85℃, react for 2 hours, and stir at 350-550 rpm.