Multiple-bed Downflow Reactor Mixing Device for Temperature Homogeneity
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Solution Overview
Problem
Multiple-bed downflow reactors face challenges in achieving uniform distribution of liquid and gas, leading to uneven reaction and temperature distribution across reaction beds, which affects process efficiency in hydrocarbon processing.
Innovation Solution
A mixing device with a loop of first nozzles directed inwardly and a loop of second nozzles directed outwardly around a vertical axis, where the ejection directions are defined by orthogonal vectors, promoting opposite circumferential directions to enhance mixing and reduce vertical height requirements, allowing for more homogeneous temperature distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a conventional mixing device with single-direction nozzles is used, then the device structure is simple, but the temperature distribution uniformity deteriorates
Solution Approach 1:
The mixing device is segmented into multiple nozzle loops (first loop, second loop, third loop) with different ejection directions. Each loop handles a specific directional component of the fluid mixture, dividing the complex mixing task into manageable segments that collectively achieve uniform temperature distribution.
Solution Approach 2:
Different nozzle loops are positioned and oriented to address specific local mixing requirements within the inter-bed space. The first loop targets radial mixing, the second loop addresses tangential mixing, and the third loop handles axial mixing, ensuring that each region receives appropriate mixing intensity and direction.
2Productivity
If the inter-bed vertical height is reduced by 20-40%, then reactor productivity increases, but the mixing effectiveness deteriorates
Solution Approach 1:
The mixing device utilizes three-dimensional nozzle arrangements with components in radial, tangential, and axial directions. This multi-dimensional approach to fluid ejection ensures effective mixing is achieved within a compressed vertical space, maintaining mixing quality while reducing the inter-bed height.
Solution Approach 2:
The mixing device creates dynamic fluid motion through multiple ejection directions and utilizes the natural downward flow of liquid from the upper bed. The combination of injected gas/liquid from nozzles and the descending liquid creates turbulent mixing that is effective in reduced vertical distances.
3Stability of the object's composition
If multiple nozzle loops with different ejection directions are added, then the temperature homogeneity improves, but the device complexity increases
Solution Approach 1:
The multiple nozzle loops serve universal mixing functions despite their different orientations. All loops work together to achieve the same overall goal of temperature homogenization, with each loop contributing a specific directional component to the mixed fluid stream.
Solution Approach 2:
The first, second, and third nozzle loops are merged into a single integrated mixing device assembly. Their combined effect creates comprehensive three-dimensional mixing action, merging their individual contributions to achieve superior temperature homogeneity that neither loop could accomplish alone.
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 increases reactor performance by reducing the vertical height of inter bed spaces by 20-40%, enabling more beds or increased performance, with improved temperature homogeneity and reduced standard deviation of temperature across the reactor.
Implementation Method 1
promoting opposite circumferential directions to enhance mixing
Implementation Method 2
a loop of first nozzles distributed around a vertical axis and arranged for ejecting a fluid in a first ejection direction
Implementation Method 3
a swirler, which swirler is located above the collecting tray around the central gas passage, and is provided with vanes defining a swirl direction and being arranged to impart a swirling motion to gas passing through the central gas passage
Data Source
AI summary
The present invention relates to a multiple-bed downflow reactor comprising vertically spaced beds of solid contact material and a mixing device positioned in an inter bed space between adjacent beds. The mixing device comprises a loop of first nozzles distributed around a vertical axis and arranged for ejecting a fluid in a first ejection direction into said inter bed space, on the one hand, and a loop of second nozzles distributed around the vertical axis and arranged for ejecting a fluid in a second ejection direction into said inter bed space, on the other hand. The first ejection direction is directed inwardly with respect to the loop of first nozzles. The second ejection direction is directed outwardly with respect to the loop of second nozzles.