Olefin Polymerization Reactor Integral Separator for Heat Removal
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Solution Overview
Problem
Current gas fluidized bed reactors for olefin polymerization face limitations in heat removal, leading to degradation of catalysts and polymers, agglomeration, and reduced production rates due to insufficient cooling capacity, which restricts the amount of liquid in the recycle stream without destabilizing the fluidized bed.
Innovation Solution
A process involving a vertically extended reactor with an integral gas/liquid separator allows for a higher percentage of liquid in the recycle stream by separating and reintroducing the liquid phase with a solid catalyst, forming a slurry stream that can be fed back into the reactor, enabling increased cooling and production rates without destabilizing the bed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the amount of liquid in the recycle stream is increased to improve heat removal, then the cooling capacity increases, but the fluidized bed becomes destabilized
Solution Approach 1:
The recycle stream is segmented into gas phase and liquid phase components. The gas phase is returned to the reactor to maintain fluidization, while the liquid phase is separated and used for cooling purposes, allowing independent optimization of both fluidization stability and heat removal capacity
Solution Approach 2:
The liquid phase is extracted from the recycle stream through a gas/liquid separator. This extracted liquid can be used for cooling without being reintroduced to the reactor, thereby removing the constraint that previously forced a trade-off between liquid amount and bed stability
2Productivity
If the cooling capacity is increased to improve production rate, then the polyolefin production rate increases, but the catalyst and polymer degradation occurs
Solution Approach 1:
The process utilizes phase transition of the condensable component from gas to liquid in the cooling section, and from liquid to vapor when reintroduced to the reactor. This phase change mechanism provides efficient heat removal capability that can support higher production rates without causing thermal degradation of catalyst or polymer
3Temperature
If external cooling systems are added to improve heat removal, then the cooling efficiency increases, but the device complexity increases
Solution Approach 1:
The recycle stream serves multiple functions: it maintains fluidization of the bed (gas phase), provides heat removal capacity (liquid phase through evaporation), and acts as a monomer feed source. This multi-functionality eliminates the need for separate dedicated cooling systems, maintaining simplicity while achieving efficient heat removal
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 process allows for up to 50% liquid in the reactor feed, increasing production rates by 20% and catalyst productivity by 10%, reducing fines and fouling, and enabling the production of polyolefins with higher bulk density and homogeneity.
Implementation Method 1
cooling the recycle stream to below its dew point to produce a mixture of cold gas and liquid
Implementation Method 2
the liquid portion will vaporize upon exposure to the heat of the reactor, which vaporization will remove heat from the reactor
Implementation Method 3
the heat of polymerization is used to vaporise the liquid condensable component
Data Source
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AI summary
The invention relates to a system suitable for the continuous polymerization of one or more α-olefin monomers of which at least one is ethylene or propylene comprising a reactor (8), a compressor (400), a cooling unit (5) and an external pipe (11) for the production of a prepolymer and/or polymer, wherein the reactor comprises a first outlet for a top recycle stream (40), wherein the system comprises apparatus for condensing the top recycle stream into a bottom recycle stream, wherein the reactor comprises a first inlet for receiving a bottom recycle stream (10), wherein the first inlet for receiving the bottom recycle stream is located underneath the distribution plate (6), wherein the reactor comprises an integral separator (1) for separation of the bottom recycle stream into a gas/liquid and a liquid phase, wherein the integral separator is located underneath the distribution plate (6), wherein the first inlet of the integral separator is connected to a first outlet for a liquid phase, wherein the first outlet for the liquid phase is connected to the second outlet of the reactor for the liquid phase, wherein the second outlet of the reactor provides the liquid phase to the first inlet of the external pipe (11), wherein the external pipe comprises a second inlet for receiving a solid polymerization catalyst (20), wherein the first outlet of the external pipe is connected to a second inlet of the reactor for receiving a slurry phase comprising the prepolymer and/or polymer, wherein the reactor comprises a third outlet for providing polyolefin (30), wherein the system comprises a first inlet for receiving a feed (60) and optionally a second inlet for receiving a feed (70).