Polyolefin Degassing Vessel Buffering for Uninterrupted Polymerization
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Solution Overview
Problem
Existing processes for producing polyolefin polymers require additional storage containers and pneumatic transport steps, increasing costs and complexity, as they need to buffer polyolefin particles before pelletizing, especially when the melt mixing device is stopped temporarily.
Innovation Solution
A process where polyolefin particles are degassed in a vessel that also acts as a buffer, allowing continued polymerization without additional storage, by using multiple degassing steps including a final step with a nitrogen stream, and transferring particles directly to a melt mixing device without intermediate storage, utilizing previously used nitrogen and steam for catalyst deactivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional storage containers and pneumatic transport steps are added to buffer polyolefin particles before pelletizing, then production flexibility is improved, but device complexity and costs increase
Solution Approach 1:
The degassing vessel is designed to serve dual functions: it performs the degassing operation and simultaneously acts as a buffer storage container for polyolefin particles. This multi-functionality eliminates the need for separate storage containers and reduces device complexity while maintaining production flexibility.
Solution Approach 2:
The invention merges the degassing function and buffer storage function into a single integrated vessel. By combining these two previously separate operations into one unit, the system reduces the number of components, simplifies the overall device structure, and eliminates intermediate pneumatic transport steps.
2Adaptability or versatility
If additional storage containers and pneumatic transport steps are added to buffer polyolefin particles, then production flexibility is improved, but costs increase
Solution Approach 1:
The degassing vessel performs multiple functions including degassing and buffer storage, eliminating the need for additional storage containers and associated pneumatic transport equipment. This reduction in equipment requirements directly lowers manufacturing costs while preserving production flexibility.
Solution Approach 2:
By combining degassing and buffer functions into one vessel, the invention reduces the total number of components that need to be manufactured, installed, and maintained, thereby reducing overall system costs while maintaining operational flexibility.
3Quantity of substance
If polyolefin particles are transferred through intermediate storage and pneumatic transport, then buffer capacity is improved, but loss of time and productivity occur
Solution Approach 1:
The degassing vessel is designed with sufficient volume to provide buffer capacity while eliminating intermediate transfer steps. Particles remain in the same vessel throughout the degassing process, avoiding time losses associated with pneumatic transport to and from separate storage containers.
Solution Approach 2:
The continuous degassing process occurs without interruption by intermediate transfers. The degassing vessel maintains a continuous supply of particles for the melt mixing device, ensuring uninterrupted production flow and maximizing productivity while providing necessary buffer capacity.
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 eliminates the need for intermediate storage and pneumatic transport, maintaining production flexibility and reducing costs by using the degassing vessel as a buffer, ensuring uninterrupted polymerization and simplified particle flow.
Implementation Method 1
contacting the polyolefin particles with a nitrogen stream in a degassing vessel
Implementation Method 2
de-gassing by a process comprising at least a final step of contacting the polyolefin particles with a nitrogen stream
Implementation Method 3
deactivating the polymerization catalyst and/or cocatalysts, e.g. by reacting the catalyst and/or cocatalysts with water
Implementation Method 4
transferred to a melt mixing device, in which the polyolefin particles are melted, mixed
Data Source
Figure 1
AI summary
Process for preparing a polyolefin polymer comprising the steps of a) forming a particulate polyolefin polymer by polymerizing one or more olefins in the presence of a polymerization catalyst system in a polymerization reactor; b) discharging the formed polyolefin particles from the polymerization reactor; c) degassing the polyolefin particles by a process comprising at least a final step of contacting the polyolefin particles with a nitrogen stream in a degassing vessel; and d) transferring the polyolefin particles from the vessel, in which the contacting of the polyolefin particles with the nitrogen stream is carried out, to a melt mixing device, in which the polyolefin particles are melted, mixed and thereafter pelletized, without passing the particles through a buffering device, wherein the degassing vessel is only partly filled with polyolefin particles and the empty volume within the degassing vessel is sufficient to take up additional polyolefin particles for at least 3 hours if the transfer of polyolefin particles of step d) from the degassing vessel to the melt mixing device is discontinued and the discharge of polyolefin particles from the polymerization reactor according to step b) is continued with unchanged rate.