Double Cone Fluidized Bed Reactor with Series Cyclones
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Solution Overview
Problem
Conventional fluidized bed reactors face issues with particle segregation, homogeneity, and operability due to broad particle size distribution and high risk of reactor shutdown from particle carryover and fouling, especially at high superficial gas velocities.
Innovation Solution
A double cone reactor structure with at least three cyclones connected in series for agglomerate removal, allowing for high superficial gas velocities and extended residence time of small particles, which results in a narrower particle size distribution and improved bed homogeneity without the need for mixing devices or distribution plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high superficial gas velocity is used to improve productivity, then production rate increases, but particle carryover and fouling risk increase leading to reactor shutdown
Solution Approach 1:
The invention extracts and removes particles from the gas stream using cyclones connected in series. The first cyclone removes larger particles, while subsequent cyclones remove finer particles, preventing carryover and fouling in the reactor while allowing high gas velocities for improved productivity
Solution Approach 2:
The cyclones act as intermediary devices between the reactor and the environment, capturing particles that would otherwise cause fouling and shutdowns. This mediator system allows the reactor to operate at high gas velocities without direct exposure of particles to downstream equipment
2Reliability
If conventional bubbling fluidized bed is used to maintain moderate gas velocity, then particle carryover is limited, but particle segregation and bed homogeneity deteriorate
Solution Approach 1:
The invention segments the particle separation process into multiple stages using series-connected cyclones. Each cyclone handles a specific particle size range, with the first cyclone removing larger particles and subsequent cyclones removing finer particles, achieving complete particle removal without segregation
Solution Approach 2:
The invention transitions from a single-dimension bubbling flow pattern to a multi-dimensional particle circulation system. Particles are circulated through multiple cyclones in series, creating complex flow paths that enhance mixing and prevent segregation while maintaining bed homogeneity
3Stability of the object's composition
If mixing devices and distribution plates are added to improve bed homogeneity, then particle distribution improves, but device complexity increases
Solution Approach 1:
The reactor system performs self-service for particle distribution and mixing through the cyclone circulation arrangement. The gas-solid flow pattern and cyclone-induced particle circulation automatically maintain bed homogeneity without requiring additional mixing devices or distribution plates
Solution Approach 2:
The invention removes unnecessary components (mixing devices and distribution plates) from the reactor structure. Instead of adding complexity, the system uses external cyclones to handle particle separation and circulation, simplifying the reactor design while maintaining bed homogeneity
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 configuration achieves reduced particle segregation, enhanced mixing, and stable reactor operation with improved mass and heat transfer, leading to polymers with uniform molecular properties and easier downstream processing.
Implementation Method 1
directing the first stream comprising fluidization gas and particles of olefin polymer to a series of at least three cyclones connected to the fluidized bed reactor thereby obtaining from the last cyclone in the series a final stream of fluidization gas depleted of olefin polymer particles
Implementation Method 2
polymerizing in a fluidized bed polymerization reactor comprising a fluidized bed in the reactor... in the presence of a polymerization catalyst and fluidization gas
Data Source
AI summary
A method and arrangement of producing polymer comprising polymerizing in reactor having a top zone having a generally conical shape, a middle zone in direct contact with and below said top zone having a generally cylindrical shape, a bottom zone having a generally conical shape thereby polymerizing at least one olefin, in the presence of a polymerization catalyst and fluidization gas to obtain (i) a first stream comprising fluidization gas and particles of olefin polymer, (ii) a second stream comprising fluidization gas and agglomerates of olefin polymer, (iii) a third olefin polymer product stream, —directing the first stream comprising fluidization gas and olefin polymer particles to a series of at least three cyclones connected to the fluidized bed reactor, —separating agglomerates of olefin polymer from the second stream, withdrawing from the fluidized bed polymerization reactor the third olefin polymer product stream.