Donut-Shaped Mixing Device for Multi-Bed Reactor Volume Reduction
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Solution Overview
Problem
Current multi-bed hydroprocessing reactors have a significant volume occupied by the quench section, which includes mixing devices, distributor trays, and catalyst support grids, limiting active reactor volume and requiring extensive space for maintenance and access, while existing mixers do not efficiently occupy less reactor space with minimal pressure drop.
Innovation Solution
A cylindrical mixing device with a donut shape is positioned between catalyst beds, featuring collecting, mixing, and discharging sections outside the reactor's center, utilizing circular arc divider walls for efficient 3-level mixing and minimizing reactor height, allowing for reduced volume occupation and easier maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional quench section components (mixing devices, distributor trays, catalyst support grids) are installed between catalyst beds, then cooling and mixing functions are achieved, but significant reactor volume is occupied and active reactor volume is limited
Solution Approach 1:
The patent combines the mixing device and distributor tray into a single integrated unit. The mixing device includes a mixing section with radial vanes for mixing fluid, and a distributor section with distribution holes directly below, eliminating the need for separate distributor trays and support grids. This merging reduces the number of components and the volume they occupy in the reactor.
Solution Approach 2:
The integrated mixing and distributor device performs multiple functions simultaneously: it cools the effluent from the upper catalyst bed, mixes the cooled fluid, and distributes the mixed fluid to the lower catalyst bed through distribution holes. This multi-functionality eliminates the need for separate dedicated components for each function, reducing overall volume occupation.
2Reliability
If multiple separate components (mixing devices, distributor trays, support grids) are installed in the quench section, then cooling and distribution functions are performed, but extensive space is required for installation, maintenance, and cleaning access
Solution Approach 1:
By merging the mixing device and distributor tray into one integrated component, the number of separate parts that require individual access for maintenance and cleaning is reduced. The integrated design allows for easier access and simpler maintenance procedures compared to navigating around multiple separate components.
Solution Approach 2:
The integrated mixing and distributor device can be designed as a removable module that can be extracted as a single unit for maintenance and cleaning. This extraction capability simplifies maintenance operations compared to disassembling and accessing multiple separate components individually.
3Stability of the object's composition
If conventional mixing devices are used in the quench section, then fluid mixing is achieved, but reactor height is increased and active reactor volume is reduced
Solution Approach 1:
The mixing device uses radial vanes arranged in a circular pattern to create rotational mixing action in the radial dimension, rather than relying on vertical mixing elements that would increase height. The fluid enters the mixing section and is mixed through radial circulation and rotation, achieving effective mixing without requiring additional vertical space.
Solution Approach 2:
The mixing device employs a circular arrangement of radial vanes that create curved flow paths for the fluid. This curved, rotational mixing action is more space-efficient than linear vertical mixing elements, achieving thorough mixing within a compact vertical footprint and reducing overall reactor height requirements.
4Ease of repair
If quench section components are installed with adequate spacing for maintenance access, then maintenance operations can be performed, but the volume occupied by components and access space is inactive reactor volume
Solution Approach 1:
The integrated mixing and distributor device reduces the total number of components that require maintenance access space. By combining multiple functions into one component, the volume required for accessing and maintaining individual components is reduced, thereby decreasing inactive reactor volume while still allowing necessary maintenance operations.
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
The solution achieves efficient cooling, mixing, and redistribution with minimal reactor volume usage, ensuring uniform fluid distribution to catalyst beds while providing ample space for maintenance and reducing reactor height, thus enhancing reactor efficiency and operational convenience.
Implementation Method 1
utilizing circular arc divider walls for efficient 3-level mixing
Implementation Method 2
the quench zone must achieve spatial uniformity of species / temperatures of the liquid phase leaving the section to the lower bed
Data Source
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AI summary
The present invention relates to a mixing device mounted between two catalyst beds in a multi-bed catalytic reactor with a cylindrical shape, said mixing device has a circular outer rim which corresponds to the inner wall of the reactor, the mixing device comprises; collecting means disposed in a collecting section for collecting fluid from an up- stream catalytic bed, mixing means disposed in a mixing section for mixing the collected fluid, and discharging means disposed in a discharging section for discharging the mixed fluid to a down-stream catalytic bed; wherein the collecting section, the mixing section and the discharging section are disposed outside the center of the circular cross-section of the reactor, as well as associated methods for mixing and the use of such a mixing device in catalytic reactors.