Method for Rapid Establishment of Ethylene Polymerization/Copolymerization in Gas Phase Fluidized Bed Reactor

Abstract

The invention discloses a method for quickly building ethylene polymerization / copolymerization reaction in a gas phase fluidized bed reactor. The method is characterized by comprising the following steps: after a proper seed bed is filled, feeding nitrogen to replace trace water oxygen in a reaction system, switching into ethylene, hydrogen and copolymerization monomers for component adjustment, then initiating polymerization reaction by adopting an organic chromium family S-2 type catalyst, switching into a conventional chromium family catalyst, stopping adding the organic chromium family S-2type catalyst at the same time, and carrying out catalytic ethylene polymerization / copolymerization by adopting the conventional chromium family catalyst to produce a corresponding polymer. The invention provides a method for quickly building polymerization reaction in an ethylene polymerization / copolymerization gas phase fluidized bed reactor, and in the method, change of polymerization reactionparameters is not needed, the seed bed does not need to be switched, and a small quantity of raw materials are used and the energy consumption is low during replacement of the reaction system, so that production accidents such as sheeting of the reaction system, big static electricity of a polymerization device, high content of polymer fine powder, equipment shutdown and the like are avoided, andthe production period is shortened.

Description

technical field [0001] The invention is a method for rapidly establishing ethylene polymerization / copolymerization reaction in a gas-phase fluidized bed reactor. It belongs to the preparation method of polyethylene. It particularly relates to a method for preparing corresponding polymers by catalyzing ethylene polymerization / copolymerization with conventional chromium series catalysts. Background technique [0002] The gas phase polyethylene process has the advantages of short process, small equipment footprint, low equipment investment, mild operating conditions, production unit consumption and low environmental pollution. Therefore, it was developed in the 1970s and after 30 years of rapid development. It has become the mainstream of polyethylene production technology. At present, the relatively advanced and mature full-density gas-phase process in the world mainly includes the Uniopl process of Univation Company, the Innovene G process of Ineos Company, the Spherilene p...

AI Technical Summary

Problems solved by technology

This method has the following problems: the method uses a metallocene catalyst to initiate polymerization, but the metallocene catalyst and the conventional chromium-based catalyst are poisonous to each other, and the metallocene replacement does not cut the bottom during the switching process of the catalyst. It is difficult to establish a reaction, and the consequences are to affect the quality of subsequent products and produce a large amount of transitional materials. In severe cases, it is only possible to stop the machine and change the bed

Due to the control characteristics of the fluidized bed reactor, the fluctuation of the reaction temperature will cause large static electricity and severe flakes, which will eventually lead to the shutdown of the device

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