Diglycerol Oleate Antistatic Control in Metallocene Olefin Polymerization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for controlling static charge in metallocene catalyst systems are ineffective, leading to sheeting and drooling phenomena in fluidized bed reactors, which disrupt continuous operation and reduce catalyst productivity.
Innovation Solution
An olefin polymerization method using an antistatic agent comprising diglycerol oleate mixed with a low molecular weight hydrocarbon, applied in a two-reactor system comprising a prepolymerization loop reactor and a fluidized bed reactor, to effectively manage static electricity and prevent reactor fouling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional static control agents are used in metallocene catalyst systems, then static charge is reduced, but sheeting and drooling phenomena still occur disrupting continuous operation
Solution Approach 1:
The patent changes the chemical composition parameters of the static control agent from conventional options to a specific mixture comprising isoparaffin (70-90 wt%), naphthenic hydrocarbon (5-20 wt%), and aromatic hydrocarbon (0-10 wt%). This parameter change in composition resolves the contradiction by achieving effective static control without causing sheeting or drooling phenomena, enabling continuous operation.
Solution Approach 2:
The patent uses a composite hydrocarbon mixture as the static control agent rather than a single conventional agent. The composite comprises multiple hydrocarbon types (isoparaffin, naphthenic, and aromatic hydrocarbons) in specific proportions, which synergistically provide static control functionality while preventing the harmful sheeting and drooling effects that occur with conventional agents.
2Object-generated harmful factors
If static control agents are introduced to prevent sheeting, then reactor wall adhesion is reduced, but catalyst productivity decreases
Solution Approach 1:
The patent optimizes the concentration parameter of the static control agent to 1-1000 ppm in the polymer product. This precise parameter control achieves sufficient static charge reduction to prevent wall adhesion while minimizing catalyst deactivation, thereby maintaining high catalyst productivity.
Solution Approach 2:
The patent uses a hydrocarbon-based static control agent that mimics the chemical environment of the polymerization system. Since the agent is composed of hydrocarbons similar to the monomer and polymer system, it effectively controls static charge without introducing foreign substances that would significantly interfere with catalyst activity or polymerization kinetics.
3Stability of the object's composition
If metallocene catalysts are used to achieve narrow molecular weight distribution, then product structural performance is improved, but sheeting and drooling occur in fluidized bed reactors
Solution Approach 1:
The patent introduces a hydrocarbon-based static control agent as an intermediary substance in the fluidized bed reactor. This intermediary controls the static charge between the polymer particles and reactor wall, preventing adhesion (sheeting and drooling) while allowing the metallocene catalyst to maintain its advantage of producing polymers with narrow molecular weight distribution and improved structural performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method enables long-term continuous operation and produces polyolefins suitable for various applications, including food contact uses, by maintaining stable reactor conditions and enhancing catalyst productivity.
Implementation Method 1
static electricity plays an important role in sheeting processes using Ziegler-Natta catalysts. When the static charge level on the catalyst and resin particles exceeds a certain critical level, the particles are attached to the grounded metal wall of the reactor by static forces.
Data Source
Figure 1~2
Figure 3
AI summary
Disclosed is an antistatic agent for a metallocene olefin polymerization process and a polymerization method using the same, by which discontinuity event due to sheeting or drooling occurring in the olefin polymerization process can be effectively reduced, enabling continuous operation for a long time, and the obtained final product can be applied to various applications including food contact use. The present disclosure includes an olefin polymerization method, which comprises forming a mixture in which an antistatic agent containing diglycerol oleate is mixed with a low molecular weight hydrocarbon, supplying the antistatic agent mixture and a metallocene-based catalyst composition comprising a metallocene catalyst and aluminoxane to two or more polymerization reactors, and polymerizing one or more alpha-olefins in the presence of the antistatic agent mixture and catalyst composition.