Chromium Catalyst Activation via Variable Temperature Ramp
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Solution Overview
Problem
The polyolefin production process is limited by the catalyst activation capacity and activity, leading to deteriorated catalyst quality and subsequent losses in polymer properties, with existing activation systems often overloaded, resulting in reduced polymerization rates and product quality.
Innovation Solution
Implementing a novel control of the catalyst activation process by manipulating temperature ramp rates and air flow through the catalyst activator vessel, using a multi-linear or non-linear temperature ramp and increasing air flow during the activation process to enhance catalyst conversion, specifically converting Cr3+ to Cr6+, thereby increasing catalyst activity and polyolefin production capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the catalyst activator system is overloaded to increase production capacity, then the throughput is improved, but the catalyst activation quality deteriorates leading to reduced catalyst activity
Solution Approach 1:
The patent applies dynamics by implementing variable temperature ramp rates during catalyst activation. The system transitions from a static, constant heating rate to a dynamic profile where the heating rate changes over time - initially higher to quickly activate catalyst and then reduced to maintain activation quality. This dynamic approach allows the system to handle higher catalyst loads while preserving activation quality, resolving the contradiction between throughput and quality.
2Productivity
If the temperature ramp rate is increased to reduce activation time, then the productivity is improved, but the catalyst conversion efficiency deteriorates
Solution Approach 1:
The patent segments the temperature ramp process into multiple stages with different ramp rates. The activation process is divided into an initial phase with a higher ramp rate for rapid heating, followed by a second phase with a lower ramp rate for precise control of the activation reaction. This segmentation allows the system to achieve both fast activation and high conversion efficiency by applying appropriate heating rates at different stages of the process.
3Reliability
If the air flow rate is increased to improve oxygen supply for catalyst conversion, then the catalyst activity is improved, but the energy consumption increases
Solution Approach 1:
The patent applies preliminary action by providing a controlled atmosphere in the catalyst activator vessel before and during the activation process. Instead of relying solely on high air flow rates to supply oxygen, the system pre-establishes an oxygen-containing atmosphere that facilitates catalyst conversion. This preliminary preparation of the reaction environment reduces the need for high energy-consuming air flow rates while maintaining effective oxygen supply for catalyst activation.
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
This approach increases catalyst activity, improves polyolefin properties, and enhances production capacity without penalizing polyolefin production rates, leading to cost savings and better reactor operability, with options for balancing conversion rates and activation times to optimize throughput and activity.
Implementation Method 1
a catalyst activator upstream of the polymerization reactor may convert Cr³⁺ to Cr⁶⁺, for example, to improve the quality of the catalyst and to increase the activity of the catalyst
Implementation Method 2
manipulating temperature ramp rates and air flow through the catalyst activator vessel, using a multi-linear or non-linear temperature ramp
Data Source
AI summary
A system and method for activating chromium catalyst, including: increasing temperature of a chromium catalyst at a first rate for a first period of time to a first temperature; and increasing temperature of the chromium catalyst at a second rate for a second period of time from the first temperature to a second temperature, wherein the first rate is greater than the second rate, and wherein the first period precedes the second period.