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CN-121994634-A - Investigation method for polymerization performance of reactor wall surface chemical treatment agent before application

CN121994634ACN 121994634 ACN121994634 ACN 121994634ACN-121994634-A

Abstract

The invention relates to a method for investigating polymerization performance of a reactor wall surface chemical treatment agent before application, which comprises the following steps of carrying out high-temperature activation on a carrier to obtain a high-temperature activated carrier, uniformly mixing the high-temperature activated carrier, a solvent and the surface chemical treatment agent, recovering the solvent, cooling with liquid nitrogen and hydrazine to obtain a loaded surface chemical treatment agent to be evaluated, adding the loaded surface chemical treatment agent to be evaluated, a cocatalyst and the solvent into a reaction kettle, introducing ethylene for polymerization reaction, separating polyethylene powder, drying the polyethylene powder, weighing, calculating the ratio of the weight of the polyethylene powder to the dosage of the loaded surface chemical treatment agent to be evaluated, and judging that the surface chemical treatment agent meets application requirements when the ratio is more than 10. The invention provides a method for inspecting polymerization performance of a reactor wall surface treating agent before application, and avoids the condition that the surface chemical treating agent is qualified after leaving a factory and is not used in application.

Inventors

  • CAI XIANGJUN
  • SUN QIAOQIAO
  • BAI LINLIN
  • CUI YU

Assignees

  • 上海立得催化剂有限公司

Dates

Publication Date
20260508
Application Date
20241104

Claims (10)

  1. 1. A method for investigating polymerization properties of a reactor wall surface chemical treatment agent before application, comprising the steps of: s1, carrying out high-temperature activation on a carrier to obtain a high-temperature activated carrier; s2, uniformly mixing the high-temperature activated carrier, the solvent and the surface chemical treatment agent, recovering the solvent, and cooling the liquid nitrogen cold hydrazine to obtain the loaded surface chemical treatment agent to be evaluated; s3, adding the loaded surface chemical treating agent to be evaluated, a cocatalyst and a solvent into a reaction kettle, introducing ethylene, carrying out polymerization reaction, and separating polyethylene powder; S4, weighing the polyethylene powder after drying, calculating the ratio of the weight (g) of the polyethylene powder to the dosage (g) of the surface chemical treatment agent to be evaluated after loading, and judging that the surface chemical treatment agent meets the application requirement when the ratio is more than 10; wherein the surface chemical treating agent contains chromium element, the promoter contains aluminum element, and the aluminum-chromium ratio is 0.01-60.
  2. 2. The method for examining the polymerization performance of the reactor wall surface chemical treatment agent before application according to claim 1, wherein in S1, the step of high-temperature activation of the carrier is specifically that the temperature is increased from room temperature to 200-250 ℃ in an equal gradient manner, the temperature is kept for 0.5-1h and 200-250 ℃ for 0.5-3h during heating, the temperature is increased for 500-600 ℃ in an equal gradient manner again, the temperature is kept for 3-4h at 1-1.5h and 500-600 ℃ during heating, and finally the temperature is reduced to room temperature in an equal gradient manner, and the temperature is reduced for 2-4h during cooling.
  3. 3. The method for examining polymerization properties before application of a chemical treatment agent for reactor wall surface according to claim 1, wherein in S1, the carrier is macroporous amorphous silica gel, and the specific surface area is not less than 200m 2 /g.
  4. 4. A method for investigating the polymerization properties of a reactor wall surface chemical treatment agent before application according to claim 3, characterized in that the specific surface area of the macroporous amorphous silica gel is 200-600m 2 /g, the pore volume is 1.0-3.8ml/g and the pore size is 25-100 μm.
  5. 5. The method for examining polymerization properties before application of a reactor wall surface chemical treatment according to claim 1, wherein in S2, the ratio of Gao Wenhuo carrier, hexane and surface chemical treatment is 10g:80ml:1.6g.
  6. 6. The method for examining polymerization properties before application of a chemical treatment agent for reactor wall surface according to claim 1, wherein in S2, the solvent is one or more of pentane, n-hexane, cyclohexane, n-heptane and toluene.
  7. 7. The method for examining polymerization properties before application of a chemical treatment agent for reactor wall surface according to claim 1, wherein in S2, the particle size of the catalyst is 25-100 μm.
  8. 8. The method for examining the polymerization properties of a reactor wall surface chemical treatment agent before application according to claim 1, wherein in S3, said cocatalyst is an aluminum alkyl.
  9. 9. The method for examining the polymerization properties of a reactor wall surface chemical treatment agent before application according to claim 1, wherein in S3, the cocatalyst is triethylaluminum or triisobutylaluminum.
  10. 10. The method for examining the polymerization performance of the reactor wall surface chemical treatment agent before application, which is characterized in that S3 is specifically that a reaction kettle is heated to 60-70 ℃ and vacuumized, air in the reaction kettle is replaced by nitrogen, the loaded surface chemical treatment agent to be evaluated, a cocatalyst and hexane are added, ethylene is introduced to replace nitrogen, ethylene is continuously introduced, the temperature is raised to 75-85 ℃ and the reaction is carried out for 2 hours, and the stirring speed is 350-550rpm.

Description

Investigation method for polymerization performance of reactor wall surface chemical treatment agent before application Technical Field The invention relates to the technical field of chemical engineering, in particular to a method for investigating polymerization performance of a reactor wall surface chemical treatment agent before application. Background The reactor wall of the reactor system of the Univation-like gas-phase polyethylene device needs to be subjected to chemical treatment before starting, and the action principle of the chemical treatment agent on the surface of the reactor wall mainly ensures that a certain specific chromium ion is deposited on the wall of the reaction system, so that the sensitivity of the inner wall of the gas-phase polyethylene reactor system to static electricity can be effectively reduced. This mode of treatment is critical to ensure smooth start-up and operation of the gas phase polyethylene apparatus, as it can promote reactor performance and stability, while also contributing to improved production efficiency and product quality. In addition, the use of such surface chemistry treatments can also extend the life of the reactor to some extent, reducing the frequency of maintenance and repair, and thus reducing overall operating costs. One of the criteria for judging the quality of the surface chemical treatment agent is that a polyethylene film can be formed on the reactor wall after ethylene is introduced into the reactor. In the prior art, the appearance, the components and the like of the surface chemical treatment agent are analyzed, so that whether the surface chemical treatment agent meets a certain technical index can be judged, but the polymerization performance of the surface chemical treatment agent before application cannot be judged, the effective components of the surface chemical treatment agent are sensitive to impurities such as water and oxygen, and if the influence of the water and oxygen impurities exists, the usability, namely the polymerization performance, of the surface chemical treatment agent is greatly influenced, so that the surface chemical treatment agent is not enough in activity in the treatment reaction, and the condition that the surface chemical treatment agent is qualified in delivery and is not used in the application is easy to appear. Disclosure of Invention In order to avoid the condition that the surface chemical treating agent is qualified after leaving a factory and is not used in application, the invention provides a method for inspecting polymerization performance of the surface chemical treating agent of a reactor wall before application. The aim of the invention can be achieved by the following technical scheme: a method for examining polymerization performance of a reactor wall surface chemical treatment agent before application comprises the following steps: s1, carrying out high-temperature activation on a carrier to obtain a high-temperature activated carrier; s2, uniformly mixing the high-temperature activated carrier, the solvent and the surface chemical treatment agent, recovering the solvent, and cooling the liquid nitrogen cold hydrazine to obtain the loaded surface chemical treatment agent to be evaluated; s3, adding the loaded surface chemical treating agent to be evaluated, a cocatalyst and a solvent into a reaction kettle, introducing ethylene, carrying out polymerization reaction, and separating polyethylene powder; S4, drying polyethylene powder, weighing, calculating the ratio of the weight (g) of the polyethylene powder to the amount (g) of the surface chemical treating agent to be evaluated after loading, judging that the activity of the surface chemical treating agent is not affected when the ratio is more than or equal to 10, preferably 10-125, supposing that the surface chemical treating agent can be successfully polymerized to generate polyethylene when being applied, and meeting the application requirements, and according to industrial application experience, considering that the polyethylene can not be completely covered on the surface of a reactor in actual application, the requirement that the polyethylene combined on the surface of the reactor after the surface treatment is polymerized to be 10-125 times of the surface chemical treating agent can be met. Wherein the surface chemical treating agent contains chromium element, the promoter contains aluminum element, and the aluminum-chromium ratio is 0.01-60, preferably 10-60. Further, in S1, the high-temperature activation of the carrier is carried out by heating from room temperature to 200-250 ℃ in an equal gradient manner, heating for 0.5-1h, preserving heat for 0.5-3h at 200-250 ℃, heating for 500-600 ℃ in an equal gradient manner again, preserving heat for 3-4h at 1-1.5h and 500-600 ℃, and finally cooling to room temperature in an equal gradient manner, and cooling for 2-4h. The key components of the surface chemical treatment agent are sensi