Vortex Mixing Device for Hydroprocessing Reactor Interbeds

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Solution Overview

Problem

In down-flow hydroprocessing reactors, poor interbed fluid mixing leads to temperature maldistribution, hot spots, and reduced reactor performance, necessitating improved mixing devices with a lower vertical footprint for efficient operation and retrofitting existing reactors.

Innovation Solution

A vortex-type mixing device with a horizontal top plate, base plate, inwardly-curved vanes, a vertical weir ring, and a bubble cap, designed to enhance mixing of gas and liquid phases in the interbed space of multi-bed reactors, reducing pressure drop and increasing throughput.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If traditional mixing devices are used in the interbed space, then fluid mixing can be achieved, but the vertical footprint is large which reduces catalyst loading volume

Engineering Contradiction:
Improvecatalyst loading volumeVSAvoidmixing device vertical footprint
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The mixing device transitions from a vertical stacking arrangement to a horizontal radial flow arrangement. Fluid enters at the periphery and moves radially inward through the mixing chamber, utilizing horizontal space rather than vertical space. This dimensional change allows effective mixing to occur within a compressed vertical envelope, thereby increasing catalyst loading volume without sacrificing mixing performance.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The mixing chamber employs curved surfaces including a domed top surface and a rounded bottom surface with a central outlet aperture. These curved geometries promote smooth fluid flow patterns and enhance mixing efficiency while maintaining a compact vertical profile. The spherical-like geometry allows the device to achieve effective mixing in a smaller vertical space compared to traditional linear or angular designs.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Productivity

If the interbed space is reduced to increase catalyst loading, then reactor throughput is improved, but fluid mixing becomes insufficient leading to temperature maldistribution

Engineering Contradiction:
Improvereactor throughputVSAvoidtemperature uniformity
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The device utilizes hydraulic principles to create a vortex flow pattern within the mixing chamber. The radial flow design combined with the curved surfaces generates rotational motion that enhances liquid-gas mixing and heat transfer. This hydraulic vortex action ensures uniform temperature distribution and effective fluid mixing within the reduced interbed space, preventing hot spots while maintaining high reactor throughput.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The mixing device changes the flow parameters of the liquid and gas streams by converting axial flow into radial and rotational flow components. This parameter transformation creates enhanced mixing conditions and improved heat transfer coefficients, allowing uniform temperature distribution to be achieved in a more compact interbed space, thereby supporting higher reactor throughput.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If mixing efficiency is increased to eliminate hot spots, then temperature distribution improves, but pressure drop increases

Engineering Contradiction:
Improvetemperature distributionVSAvoidpressure drop
Core Design Contradiction:
TemperatureVSStress or pressure

Solution Approach 1:

The distributed outlet apertures around the central outlet create a porous-like flow distribution pattern. Multiple small flow paths are provided instead of a single large opening, which distributes the pressure drop across numerous pathways. This approach maintains effective mixing and uniform temperature distribution while minimizing the overall pressure drop through the mixing device.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The outlet is segmented into multiple distributed apertures rather than a single centralized outlet. This segmentation creates multiple parallel flow paths that reduce resistance to flow and minimize pressure drop. Simultaneously, the distributed outlets maintain effective mixing by releasing fluid at multiple locations, ensuring uniform temperature distribution without the penalty of high pressure drop.

Inventive Principle:
Principle #1Segmentation

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 vortex-type mixing device achieves effective fluid mixing with a reduced vertical footprint, enhancing reactor performance, throughput, and allowing for efficient retrofitting of existing reactors, while minimizing pressure drop and maintaining uniform temperature distribution.

Implementation Method 1

A vortex-type mixing device with a horizontal top plate, base plate, inwardly-curved vanes, a vertical weir ring, and a bubble cap, designed to enhance mixing of gas and liquid phases in the interbed space of multi-bed reactors

Methodology Applied
Scientific EffectVortex flow: Vortex Ring

Implementation Method 2

vortex-type mixing device... achieves effective fluid mixing with a reduced vertical footprint

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2914375B1Vortex-type mixing device for a down-flow hydroprocessing reactor
Publication Date: 2020.01.08 CHEVRON USA INC
  • EP2914375B1 patent drawingFigure 1
  • EP2914375B1 patent drawingFigure 2
  • EP2914375B1 patent drawingFigure 3

AI summary

The present invention is directed to a vortex-type mixing device for a down- flow hydroprocessing reactor. In particular, the device improves the effectiveness of an existing mixing volume in mixing the gas phase and liquid phase of two-phase systems. According to the present invention, the mixing device helps create a highly arcuate flow to incoming effluents and a high degree of mixing within a constrained interbed space of a hydroprocessing reactor.