Reactor Downcomer Helical Baffle for Gas-Catalyst Separation
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Solution Overview
Problem
In hydrocarbon upgrading reactors, the presence of gas bubbles in the downcomer reduces the efficiency of recirculation pumps and mixing, and there is a need to separate heavy, deactivated catalyst from active catalyst to facilitate regeneration.
Innovation Solution
A downcomer with a baffle structure that induces a downward helical flow, centrifugally separating denser components from less dense ones, allowing denser components to be collected and directed for regeneration while promoting gas bubble escape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gas bubbles are present in the downcomer, then the multi-phase mixture can be recirculated, but pump efficiency is reduced and mixing is impaired
Solution Approach 1:
The downcomer is divided into two distinct regions by a vertical barrier: an inner region where helical flow occurs and an outer region where gas bubbles are collected. This segmentation allows gas-liquid separation while maintaining recirculation efficiency.
Solution Approach 2:
The gas phase is extracted from the liquid stream through centrifugal separation in the inner region, allowing the liquid to be recirculated more efficiently. The gas is removed in the outer region and can be vented or reused.
2Productivity
If heavy deactivated catalyst is mixed with active catalyst, then the catalyst can be recirculated, but separation for regeneration is impaired
Solution Approach 1:
The downcomer interior is segmented into inner and outer regions separated by a vertical barrier. The baffle structure creates flow paths that separate denser deactivated catalyst from lighter active catalyst through centrifugal forces during helical flow.
Solution Approach 2:
Different regions of the downcomer have different functions: the inner region provides helical flow for centrifugal separation, while the outer region collects and channels the separated heavy catalyst for regeneration. This local differentiation improves separation efficiency.
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
Enhances the separation of gas from the multi-phase mixture, improves pump efficiency, and facilitates the removal and regeneration of heavy, deactivated catalyst, thereby optimizing the reactor's performance.
Implementation Method 1
a baffle structure arranged to induce the mixture to flow in a downward generally helical path such that denser components of the mixture are centrifugally urged outwardly away from a center of the downcomer and less dense components migrate toward the center
Implementation Method 2
Due to the degassing section being of relatively large diameter, travel of the multi-phase mixture therein is slower than the natural ascension velocity of the hydrogen gas bubbles, thereby facilitating escape of the bubbles from the rest of the multi-phase flow
Data Source
AI summary
A downcomer for a reactor for downwardly conducting a multi-phase mixture, the downcomer includes a transport section having an interior comprised of inner and outer regions separated horizontally by a vertical barrier, and a baffle structure disposed on an inner surface of the barrier. The baffle structure is arranged to induce the mixture to flow in a downward generally helical path such that denser components of the mixture are centrifugally urged outwardly away from a center of the downcomer and less dense components migrate toward the center. The barrier includes openings enabling the denser components to travel from the inner region to the outer region to be collected herein.