Fluid Distribution Device for Multibed Reactors
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Solution Overview
Problem
In co-current flow reactors, the existing systems face challenges in efficiently controlling and distributing fluid temperature and composition between catalyst beds, leading to uneven reactions and rapid catalyst deactivation due to hot spots, especially in hydrocarbon processing where space constraints limit the installation of new internals for improved mixing and distribution.
Innovation Solution
The introduction of a device and method that includes a collection tray, mixing chamber, rough distribution tray, and vapor chimneys with a radially inwardly tapered cross section to facilitate the mixing and distribution of fluids between catalyst beds, reducing the height of the interbed space while maintaining effective fluid distribution and temperature uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If complex mixing and distribution systems are used to improve temperature and composition distribution, then mixing effectiveness is improved, but device complexity and space consumption increase
Solution Approach 1:
The mixing and distribution system is segmented into distinct functional components: a collection tray for receiving fluid from the upper bed, a mixing chamber for temperature and composition mixing, a rough distribution tray for initial distribution, and a fine distribution tray for final uniform distribution. This segmentation allows each component to perform its specific function efficiently without requiring a complex integrated system.
Solution Approach 2:
A quench fluid is introduced as an intermediary substance in the interbed space to facilitate heat transfer and improve mixing. The quench fluid acts as a mediator between the hot effluent from the upper catalyst bed and the feed to the lower bed, enabling effective temperature control and composition mixing without complex mechanical mixing devices.
2Stability of the object's composition
If more space is allocated for quench fluid injection and mixing, then mixing effectiveness is improved, but the height of interbed space increases
Solution Approach 1:
The distribution trays utilize the radial dimension for fluid distribution, with outlets arranged circumferentially around the central mixing chamber outlet. This radial distribution approach allows effective mixing and distribution to occur in a compact vertical space, reducing the interbed height requirement while maintaining mixing effectiveness.
Solution Approach 2:
The fine distribution tray is positioned within the space defined by the rough distribution tray, creating a nested arrangement where the fine distribution outlets are located below and within the radial extent of the rough distribution tray. This nesting allows multiple distribution functions to occupy overlapping spatial envelopes, maximizing catalyst loading density while maintaining adequate mixing space.
3Stability of the object's composition
If the height of catalyst beds is reduced to accommodate new internals, then interbed space for mixing is improved, but catalyst loading capacity decreases
Solution Approach 1:
The distribution system is designed to be adaptable to different reactor configurations and operating conditions. The trays and chimneys can be adjusted or reconfigured to optimize performance for different catalyst bed heights and quench fluid injection rates, allowing the system to maintain effective mixing and distribution without requiring fixed catalyst bed dimensions.
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 solution enhances fluid mixing and distribution, reducing the height of the interbed space by up to 200 mm, minimizing temperature and composition differences, and extending catalyst life while maximizing catalyst loading and reducing capital expenses.
Implementation Method 1
a distribution tray vapor chimney of the distribution tray positioned radially outwardly of the mixing chamber outlet and an upper opening of the distribution tray vapor chimney above a normal operation liquid level of the distribution tray that provides fluid communication from above to below the rough distribution tray
Implementation Method 2
The space between catalyst beds is for the injection of a quench gas or liquid and for fluid mixing and distribution
Implementation Method 3
In hydrocarbon processing, the quench gas is often a cool hydrogen/hydrocarbon stream
Data Source
AI summary
A fluid distribution device and method is presented for the collection and distribution of fluid between reactor beds. According to various aspects, the method includes a collection tray, a mixing chamber in fluid communication with the collection tray, a rough distribution tray in fluid communication with the mixing chamber, and a fine distribution tray in fluid communication with the rough distribution tray. The rough distribution tray includes a vapor chimney.