Fluidized-Bed Reactor Gas Inlet Nozzle Segmentation
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Solution Overview
Problem
Fluidized-bed reactors for gas-phase polymerization of olefins have inefficiencies due to the large volume below the gas distribution grid, which increases construction costs and allows polymer particles to be deposited in non-productive areas, reducing production efficiency.
Innovation Solution
The reactor design includes a gas recycle line that splits into two horizontal branches tangentially connected below the gas distribution grid, an inverted cone-shaped grid with annular modules, and a polymer discharge pipe integrated with the grid, along with a non-pressure-resistant divider plate to maintain pressure equality and prevent particle deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a large gas inlet nozzle is used to introduce high amounts of fluidization gas, then the gas distribution is improved, but the volume below the gas distribution grid increases, leading to larger reactor size and higher construction costs
Solution Approach 1:
The gas inlet nozzle is divided into multiple smaller nozzles arranged in a specific pattern below the gas distribution grid. This segmentation allows the same total gas flow to be distributed through multiple entry points, improving gas distribution uniformity while reducing the required volume below the grid compared to a single large nozzle
Solution Approach 2:
The gas inlet system transitions from a single large-dimensional nozzle to multiple smaller nozzles distributed in a two-dimensional arrangement below the grid. This dimensional change maintains the necessary gas introduction capacity while minimizing the vertical space requirement below the distribution grid
2Ease of operation
If a large volume is provided below the gas distribution grid for gas inlet, then gas introduction is facilitated, but polymer particles can be deposited in this non-productive area, reducing production efficiency
Solution Approach 1:
The gas introduction function is segmented into multiple small nozzles rather than one large opening, which reduces the surface area where polymer particles could deposit while maintaining effective gas distribution into the fluidized bed
Solution Approach 2:
The harmful function of the large volume below the grid (particle deposition zone) is eliminated by minimizing this space through the use of multiple small nozzles, extracting only the necessary gas introduction capability while removing the non-productive deposition area
3Volume of stationary object
If the gas recycle line is connected directly below the gas distribution grid, then the reactor volume is reduced, but polymer particles may be carried into the recycle line and deposited
Solution Approach 1:
The gas recycle line connection is positioned in a horizontal dimension below the gas distribution grid rather than vertically, creating a spatial separation that minimizes particle carry-over while maintaining compact reactor volume
Solution Approach 2:
The connection point of the gas recycle line is specifically positioned at a location below the gas distribution grid where gas velocity is lower and particle suspension is minimal, creating a local zone that is less prone to particle deposition while still achieving compact reactor design
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 reduces the non-productive volume below the gas distribution grid, enhances gas distribution for efficient polymerization, and prevents polymer particle deposition, thereby improving production efficiency and reducing construction costs.
Implementation Method 1
fluidized-bed reactors are used for carrying out such gas-phase polymerization processes and contain a bed of polymer particles which is maintained in a fluidized state by an upward flow of a fluidizing gas
Implementation Method 2
a recycle gas line in which coolers for removing the heat of polymerization
Implementation Method 3
a recycle gas compressor
Data Source
AI summary
Fluidized-bed reactor for the gas-phase polymerization of olefins including a gas distribution grid installed in a lower part of the fluidized-bed reactor and a gas recycle line, which is equipped with a compressor and a heat exchanger and which is connected at the upper end with the top of the fluidized-bed reactor, wherein the gas recycle line splits at the lower end in at least two horizontal branches which are connected tangentially with the fluidized-bed reactor below the gas distribution grid and a process for preparing an olefin polymer carried out in the fluidized-bed reactor.