Polymerization Catalyst Delivery Control
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Solution Overview
Problem
Conventional catalyst feeding systems in polyolefin production require complex and costly equipment for mixing and dilution, leading to inconsistent catalyst concentration and reaction rates, resulting in variable polyolefin properties.
Innovation Solution
A continuous process and system for detecting changes in catalyst and monomer concentrations, and polymer production rates to adjust catalyst flow rates, eliminating the need for extensive mixing and dilution tanks, and utilizing a precontactor with multiple mixing stages to ensure consistent catalyst contact time and equilibrium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mixing and dilution tanks with diaphragm slurry pumps are used to deliver catalyst, then catalyst delivery is achieved, but the equipment becomes massive, complex, and expensive to install and maintain
Solution Approach 1:
The patent extracts and eliminates the complex mixing and dilution tanks with diaphragm slurry pumps from the catalyst delivery system. Instead, it uses a simplified system with a catalyst feeder that directly introduces catalyst components into the polymerization reactor, removing the problematic equipment while maintaining catalyst delivery functionality
Solution Approach 2:
The patent introduces a mud pot as an intermediary device between the catalyst source and the reactor. The mud pot contains a small amount of liquid to facilitate catalyst flow and ensures consistent delivery without requiring the complex tank and pump system, acting as a simple mediator that solves the delivery problem without the complexity
2Productivity
If ball check feeders are used to introduce catalyst components, then catalyst feeding is achieved, but the amount of catalyst components filling the cavity varies during rotation, resulting in inconsistent feed amounts
Solution Approach 1:
The patent implements a feedback control system that monitors the actual catalyst feed rate and adjusts the feeder operation to maintain the desired feed rate. This closed-loop control compensates for variations in cavity filling during rotation, ensuring consistent catalyst concentration and resolving the precision problem while maintaining productivity
Solution Approach 2:
The patent makes the catalyst feeding system dynamic and adjustable by using a controlled feeder mechanism that can adapt its operation based on process conditions. The system transitions from a static, fixed-feed-rate mechanism to a dynamic, controllable system that maintains precision despite variations in operation
3Adaptability or versatility
If multiple catalysts are used in polyolefin plants, then catalyst versatility is improved, but the tank requirement increases
Solution Approach 1:
The patent designs a universal catalyst delivery system that can handle multiple catalyst types through a single integrated setup. The catalyst feeder and mud pot configuration is adaptable to different catalyst forms and properties, eliminating the need for separate tank systems for each catalyst type while maintaining versatility
Data Source
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AI summary
A process is described for introducing a catalyst into a polymerization zone by detecting one or a combination of (i) a change in a concentration of the catalyst in a catalyst feed stream upstream of the polymerization zone, (ii) a change in a concentration of monomer in the polymerization zone, and (iii) a change in a polymer production rate of the polymerization zone, adjusting a first catalyst flow rate of the catalyst in the catalyst feed stream to a second catalyst flow rate based on the one or a combination of (i), (ii), and (iii), and introducing the catalyst into the polymerization zone downstream of a location in the catalyst feed stream where the step of adjusting is performed. A catalyst injection system for carrying out such a process is also provided.